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Jin Y, Yong S, Ke S, Zhang C, Liu Y, Wang J, Lu T, Sun Y, Wang H, Zhang J. Deep learning assisted fluid volume calculation for assessing anti-vascular endothelial growth factor effect in diabetic macular edema. Heliyon 2024; 10:e29775. [PMID: 38699726 PMCID: PMC11063453 DOI: 10.1016/j.heliyon.2024.e29775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 04/14/2024] [Accepted: 04/15/2024] [Indexed: 05/05/2024] Open
Abstract
Objective To develop an algorithm using deep learning methods to calculate the volume of intraretinal and subretinal fluid in optical coherence tomography (OCT) images for assessing diabetic macular edema (DME) patients' condition changes. Design Cross-sectional study. Participants Treatment-naive patients diagnosed with DME recruited from April 2020 to November 2021. Methods The deep learning network, which was built for autonomous segmentation utilizing an encoder-decoder network based on the U-Net architecture, was used to calculate the volume of intraretinal fluid (IRF) and subretinal fluid (SRF). The alterations of retinal vessel density and thickness, and the correlation between best-corrected visual acuity (BCVA) and OCT parameters were analyzed. Results 2,955 OCT images of fourteen eyes from DME patients with IRF and SRF who received anti-vascular endothelial growth factor (VEGF) agents were obtained. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve of the algorithm was 0.993 for IRF and 0.998 for SRF. The volumes of IRF and SRF were significantly decreased from 1.93 ± 0.58 /1.14 ± 0.25 mm3 (baseline) to 0.26 ± 0.13 /0.26 ± 0.18 mm3 (post-injection), respectively (p = 0.0170 for IRF, and p = 0.0004 for SRF). The Spearman correlation demonstrated that the reduction of IRF volume was negatively correlated with age (coefficient = -0.698, p = 0.006). Conclusion We developed a deep learning assisted fluid volume calculation algorithm with high sensitivity and specificity for assessing the volume of IRF and SRF in DME patients. Key words: deep learning; diabetic macular edema; optical coherence tomography.
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Affiliation(s)
- Yixiao Jin
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Clinical Research Center for Eye Diseases, Shanghai Key Clinical Specialty, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Shuanghao Yong
- School of Electrical Engineering and Automation, Anhui University, Hefei, China
| | - Shi Ke
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Clinical Research Center for Eye Diseases, Shanghai Key Clinical Specialty, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Chaoyang Zhang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Clinical Research Center for Eye Diseases, Shanghai Key Clinical Specialty, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Yan Liu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Clinical Research Center for Eye Diseases, Shanghai Key Clinical Specialty, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Jingyi Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Clinical Research Center for Eye Diseases, Shanghai Key Clinical Specialty, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Ting Lu
- Department of Ophthalmology, Jiading Branch of Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yong Sun
- Department of Ophthalmology, Jiading Branch of Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haiyan Wang
- Department of Ocular Fundus, Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, Shaanxi, China
| | - Jingfa Zhang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Clinical Research Center for Eye Diseases, Shanghai Key Clinical Specialty, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
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Kiany F, Sarafraz N, Tanideh N, Bordbar H, Andisheh-Tadbir A, Zare S, Farshidfar N, Zarei M. Bone repair potential of collagen-poly(3-hydroxybutyrate)-carbon nanotubes scaffold loaded with mesenchymal stem cells for the reconstruction of critical-sized mandibular defects. JOURNAL OF STOMATOLOGY, ORAL AND MAXILLOFACIAL SURGERY 2024; 125:101670. [PMID: 37907130 DOI: 10.1016/j.jormas.2023.101670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 10/10/2023] [Accepted: 10/25/2023] [Indexed: 11/02/2023]
Abstract
The poor structural stability of collagen (COL) upon hydration poses a significant challenge in tissue engineering (TE). To overcome this limitation, the incorporation of hydrophobic polymers such as poly(3-hydroxybutyrate) (PHB), and nanomaterials such as carbon nanotubes (CNTs) has been explored. In this study, we investigated the physical, chemical, and biological characteristics of COL-based scaffolds modified with PHB and CNTs for bone tissue engineering (BTE) applications. The tensile strength analysis revealed a substantial improvement in the ultimate tensile strength with the addition of 10 % PHB and 4 % CNTs. Scanning electron microscopy (SEM) images depicted a denser and more compact structure resulting from the presence of PHB and CNTs, enhancing the scaffold's mechanical properties. Fourier-transform infrared spectroscopy (FTIR) confirmed the successful incorporation of PHB and CNTs into the composite scaffold, maintaining the chemical integrity of COL. Stereological studies also conducted in a rat model with induced critical-sized bone defects in the mandibular bone further emphasize the substantial increase in bone formation and reduction in defect volume achieved by the scaffold loaded with stem cells. These findings underscore the promising approach to enhance bone healing, using COL-based scaffolds loaded with stem cells, and the favorable results obtained in this study can contribute to the advancement of BTE strategies.
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Affiliation(s)
- Farin Kiany
- Department of Periodontics, Oral and Dental Disease Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Najmeh Sarafraz
- Department of Periodontology, School of Dentistry, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
| | - Nader Tanideh
- Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hossein Bordbar
- Histomorphometry and Stereology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Azadeh Andisheh-Tadbir
- Department of Oral and Maxillofacial Pathology, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Shahrokh Zare
- Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Nima Farshidfar
- Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Moein Zarei
- Department of Polymer and Biomaterials Science, West Pomeranian University of Technology, Szczecin, Poland.
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3
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Pesta D. Mitochondrial density in skeletal and cardiac muscle. Mitochondrion 2024; 75:101838. [PMID: 38158151 DOI: 10.1016/j.mito.2023.101838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 11/27/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024]
Abstract
Kubat et al. provide a review on the role Mitochondrial density in skeletal and cardiac muscle of mitochondrial dysfunction in muscle atrophy. They stress mitochondria's pivotal function, citing a 52 % density in skeletal muscle. However, the reference to Park et al.'s work misinterprets their findings. Park et al. report citrate synthase (CS) activity, indicating mitochondrial density as 222 ± 13 μmol.min-1.mg-1 for cardiac muscle and 115 ± 2 μmol.min-1.mg-1 for skeletal muscle. Thus, the authors should clarify that skeletal muscle density is approximately 52 % of cardiac muscle, not an absolute 52 %. Mitochondrial volume density assessment, predominantly through TEM, establishes cardiomyocytes at 25-30 % and untrained skeletal muscle at 2-6 %, increasing to 11 % in trained athletes. However, this remains modest compared to myofibrils' 75 %-85 % of muscle fiber volume. Although the utility of CS activity is evident, TEM and other novel approaches such as three-dimensional focused ion beam scanning electron microscopy are likely superior for assessing mitochondrial volume density and morphology.
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Affiliation(s)
- D Pesta
- Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany; Centre for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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Lösel PD, Monchanin C, Lebrun R, Jayme A, Relle JJ, Devaud JM, Heuveline V, Lihoreau M. Natural variability in bee brain size and symmetry revealed by micro-CT imaging and deep learning. PLoS Comput Biol 2023; 19:e1011529. [PMID: 37782674 PMCID: PMC10569549 DOI: 10.1371/journal.pcbi.1011529] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 10/12/2023] [Accepted: 09/19/2023] [Indexed: 10/04/2023] Open
Abstract
Analysing large numbers of brain samples can reveal minor, but statistically and biologically relevant variations in brain morphology that provide critical insights into animal behaviour, ecology and evolution. So far, however, such analyses have required extensive manual effort, which considerably limits the scope for comparative research. Here we used micro-CT imaging and deep learning to perform automated analyses of 3D image data from 187 honey bee and bumblebee brains. We revealed strong inter-individual variations in total brain size that are consistent across colonies and species, and may underpin behavioural variability central to complex social organisations. In addition, the bumblebee dataset showed a significant level of lateralization in optic and antennal lobes, providing a potential explanation for reported variations in visual and olfactory learning. Our fast, robust and user-friendly approach holds considerable promises for carrying out large-scale quantitative neuroanatomical comparisons across a wider range of animals. Ultimately, this will help address fundamental unresolved questions related to the evolution of animal brains and cognition.
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Affiliation(s)
- Philipp D. Lösel
- Engineering Mathematics and Computing Lab (EMCL), Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
- Data Mining and Uncertainty Quantification (DMQ), Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
- Department of Materials Physics, Research School of Physics, The Australian National University, Canberra, Australia
| | - Coline Monchanin
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier – Toulouse III, Toulouse, France
- Department of Biological Sciences, Macquarie University, Sydney, Australia
| | - Renaud Lebrun
- Institut des Sciences de l’Evolution de Montpellier, CC64, Université de Montpellier, Montpellier, France
- BioCampus, Montpellier Ressources Imagerie, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Alejandra Jayme
- Engineering Mathematics and Computing Lab (EMCL), Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
- Data Mining and Uncertainty Quantification (DMQ), Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
| | - Jacob J. Relle
- Engineering Mathematics and Computing Lab (EMCL), Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
- Data Mining and Uncertainty Quantification (DMQ), Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
| | - Jean-Marc Devaud
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier – Toulouse III, Toulouse, France
| | - Vincent Heuveline
- Engineering Mathematics and Computing Lab (EMCL), Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
- Data Mining and Uncertainty Quantification (DMQ), Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany
- Heidelberg University Computing Centre (URZ), Heidelberg, Germany
| | - Mathieu Lihoreau
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier – Toulouse III, Toulouse, France
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Mahadev Bhat S, Yap JQ, Ramirez-Ramirez OA, Delmotte P, Sieck GC. Cell-Based Measurement of Mitochondrial Function in Human Airway Smooth Muscle Cells. Int J Mol Sci 2023; 24:11506. [PMID: 37511264 PMCID: PMC10380259 DOI: 10.3390/ijms241411506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/11/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Cellular mitochondrial function can be assessed using high-resolution respirometry that measures the O2 consumption rate (OCR) across a number of cells. However, a direct measurement of cellular mitochondrial function provides valuable information and physiological insight. In the present study, we used a quantitative histochemical technique to measure the activity of succinate dehydrogenase (SDH), a key enzyme located in the inner mitochondrial membrane, which participates in both the tricarboxylic acid (TCA) cycle and electron transport chain (ETC) as Complex II. In this study, we determine the maximum velocity of the SDH reaction (SDHmax) in individual human airway smooth muscle (hASM) cells. To measure SDHmax, hASM cells were exposed to a solution containing 80 mM succinate and 1.5 mM nitroblue tetrazolium (NBT, reaction indicator). As the reaction proceeded, the change in optical density (OD) due to the reduction of NBT to its diformazan (peak absorbance wavelength of 570 nm) was measured using a confocal microscope with the pathlength for light absorbance tightly controlled. SDHmax was determined during the linear period of the SDH reaction and expressed as mmol fumarate/liter of cell/min. We determine that this technique is rigorous and reproducible, and reliable for the measurement of mitochondrial function in individual cells.
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Affiliation(s)
| | | | | | | | - Gary C. Sieck
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA; (S.M.B.); (J.Q.Y.); (O.A.R.-R.); (P.D.)
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Li X, Helleringer R, Martucci LL, Dallérac G, Cancela JM, Galante M. Low Temperature Delays the Effects of Ischemia in Bergmann Glia and in Cerebellar Tissue Swelling. Biomedicines 2023; 11:biomedicines11051363. [PMID: 37239034 DOI: 10.3390/biomedicines11051363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/23/2023] [Accepted: 04/29/2023] [Indexed: 05/28/2023] Open
Abstract
Cerebral ischemia results in oxygen and glucose deprivation that most commonly occurs after a reduction or interruption in the blood supply to the brain. The consequences of cerebral ischemia are complex and involve the loss of metabolic ATP, excessive K+ and glutamate accumulation in the extracellular space, electrolyte imbalance, and brain edema formation. So far, several treatments have been proposed to alleviate ischemic damage, yet few are effective. Here, we focused on the neuroprotective role of lowering the temperature in ischemia mimicked by an episode of oxygen and glucose deprivation (OGD) in mouse cerebellar slices. Our results suggest that lowering the temperature of the extracellular 'milieu' delays both the increases in [K+]e and tissue swelling, two dreaded consequences of cerebellar ischemia. Moreover, radial glial cells (Bergmann glia) display morphological changes and membrane depolarizations that are markedly impeded by lowering the temperature. Overall, in this model of cerebellar ischemia, hypothermia reduces the deleterious homeostatic changes regulated by Bergmann glia.
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Affiliation(s)
- Xia Li
- Institut des Neurosciences Paris-Saclay, CNRS, Université Paris-Saclay, 91400 Saclay, France
| | - Romain Helleringer
- Institut des Neurosciences Paris-Saclay, CNRS, Université Paris-Saclay, 91400 Saclay, France
| | - Lora L Martucci
- Institut des Neurosciences Paris-Saclay, CNRS, Université Paris-Saclay, 91400 Saclay, France
| | - Glenn Dallérac
- Institut des Neurosciences Paris-Saclay, CNRS, Université Paris-Saclay, 91400 Saclay, France
| | - José-Manuel Cancela
- Institut des Neurosciences Paris-Saclay, CNRS, Université Paris-Saclay, 91400 Saclay, France
| | - Micaela Galante
- Institut des Neurosciences Paris-Saclay, CNRS, Université Paris-Saclay, 91400 Saclay, France
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Fogarty MJ, Sieck GC. Aging affects the number and morphological heterogeneity of rat phrenic motor neurons and phrenic motor axons. Physiol Rep 2023; 11:e15587. [PMID: 36695744 PMCID: PMC9875821 DOI: 10.14814/phy2.15587] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 01/26/2023] Open
Abstract
Diaphragm muscle (DIAm) motor units comprise a phrenic motor neuron (PhMN), the phrenic nerve and the muscle fibers innervated, with the size of PhMNs and axons characteristic of motor unit type. Smaller PhMNs and their axons comprise slow (type S) and fatigue-resistant (type FR) DIAm motor units, while larger PhMNs and their axons comprise more fatigable (type FF) motor units. With aging, we have shown a loss of larger PhMNs, consistent with selective atrophy of type IIx/IIb DIAm fibers and reduced maximum DIAm force. In the present study, we hypothesized that with aging there is a loss of larger myelinated phrenic α motor axons. Female and male young (6 months) and old (24 months) Fischer 344 rats were studied. PhMNs were retrogradely labeled by intrapleural injection of 488-conjugated CTB. The phrenic nerves were excised ~1 cm from the DIAm insertion and mounted in resin, and phrenic α motor axons were delineated based on size (i.e., >4 μm diameters). In older rats, the number of larger PhMNs and larger phrenic α motor axons were reduced. There were no differences in non-α axons. In addition, there was evidence of demyelination of larger phrenic α motor axons in older rats. Together, these findings are consistent with the selective age-related vulnerability of larger PhMNs and denervation of type FF motor units, which may underlie DIAm sarcopenia.
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Affiliation(s)
- Matthew J. Fogarty
- Department of Physiology & Biomedical EngineeringMayo ClinicRochesterMinnesotaUSA
| | - Gary C. Sieck
- Department of Physiology & Biomedical EngineeringMayo ClinicRochesterMinnesotaUSA
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Jakovljevic A, Agatonovic G, Aleksic D, Aksic M, Reiss G, Förster E, Stamatakis A, Jakovcevski I, Poleksic J. The impact of early life maternal deprivation on the perineuronal nets in the prefrontal cortex and hippocampus of young adult rats. Front Cell Dev Biol 2022; 10:982663. [DOI: 10.3389/fcell.2022.982663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 11/07/2022] [Indexed: 11/29/2022] Open
Abstract
Early life stress negatively impacts brain development and affects structure and function of parvalbumin immunopositive (PV+) inhibitory neurons. Main regulators of PV+ interneurons activity and plasticity are perineuronal nets (PNNs), an extracellular matrix formation that enwraps PV+ interneurons mainly in the neocortex and hippocampus. To experimentally address the impact of early life stress on the PNNs and PV+ interneurons in the medial prefrontal cortex and dorsal hippocampus in rats, we employed a 24 h maternal deprivation protocol. We show that maternal deprivation in the medial prefrontal cortex of adult rats caused a decrease in density of overall PNNs and PNNs that enwrap PV+ interneurons in the rostral cingulate cortex. Furthermore, a staining intensity decrease of overall PNNs and PNN+/PV+ cells was found in the prelimbic cortex. Finally, a decrease in both intensity and density of overall PNNs and PNNs surrounding PV+ cells was observed in the infralimbic cortex, together with increase in the intensity of VGAT inhibitory puncta. Surprisingly, maternal deprivation did not cause any changes in the density of PV+ interneurons in the mPFC, neither had it affected PNNs and PV+ interneurons in the hippocampus. Taken together, our findings indicate that PNNs, specifically the ones enwrapping PV+ interneurons in the medial prefrontal cortex, are affected by early life stress.
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Brown AD, Fogarty MJ, Davis LA, Dasgupta D, Mantilla CB, Sieck GC. Mitochondrial adaptations to inactivity in diaphragm muscle fibers. J Appl Physiol (1985) 2022; 133:191-204. [PMID: 35678745 PMCID: PMC9291409 DOI: 10.1152/japplphysiol.00090.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Type I and IIa diaphragm muscle (DIAm) fibers comprise slow and fast fatigue-resistant motor units that are recruited to accomplish breathing and thus have a high duty cycle. In contrast, type IIx/IIb fibers comprise more fatigable fast motor units that are infrequently recruited for airway protective and straining behaviors. We hypothesize that mitochondrial structure and function in type I and IIa DIAm fibers adapt in response to inactivity imposed by spinal cord hemisection at C2 (C2SH). At 14 days after C2SH, the effect of inactivity on mitochondrial structure and function was assessed in DIAm fibers. Mitochondria in DIAm fibers were labeled using MitoTracker Green (Thermo Fisher Scientific), imaged in three-dimensions (3-D) by fluorescence confocal microscopy, and images were analyzed for mitochondrial volume density (MVD) and complexity. DIAm homogenate from either side was assessed for PGC1α, Parkin, MFN2, and DRP1 using Western blot. In alternate serial sections of the same DIAm fibers, the maximum velocity of the succinate dehydrogenase reaction (SDHmax) was determined using a quantitative histochemical technique. In all groups and both sides of the DIAm, type I and IIa DIAm fibers exhibited higher MVD, with more filamentous mitochondria and had higher SDHmax normalized to both fiber volume and mitochondrial volume compared with type IIx/IIb Diam fibers. In the inactive right side of the DIAm, mitochondria became fragmented and MVD decreased in all fiber types compared with the intact side and sham controls, consistent with the observed reduction in PGC1α and increased Parkin and DRP1 expression. In the inactive side of the DIAm, the reduction in SDHmax was found only for type I and IIa fibers. These results show that there are intrinsic fiber-type-dependent differences in the structure and function of mitochondria in DIAm fibers. Following C2SH-induced inactivity, mitochondrial structure (MVD and fragmentation) and function (SDHmax) were altered, indicating that inactivity influences all DIAm fiber types, but inactivity disproportionately affected SDHmax in the more intrinsically active type I and IIa fibers.NEW & NOTEWORTHY Two weeks of diaphragm (DIAm) inactivity imposed by C2SH caused reduced mitochondrial volume density, mitochondrial fragmentation, and a concomitant reduction of SDHmax in type I and IIa DIAm fibers on the lesioned side. Type I and IIa DIAm fibers were far more sensitive to inactivation than type IIx/IIb fibers, which exhibited little pathology. Our results indicate that mitochondria in DIAm fibers are plastic in response to varying levels of activity.
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Cervical spinal hemisection alters phrenic motor neuron glutamatergic mRNA receptor expression. Exp Neurol 2022; 353:114030. [PMID: 35247372 DOI: 10.1016/j.expneurol.2022.114030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 02/18/2022] [Accepted: 02/27/2022] [Indexed: 11/22/2022]
Abstract
Upper cervical spinal cord injuries (SCI) disrupt descending inputs to phrenic motor neurons (PhMNs), impairing respiratory function. Unilateral spinal hemisection at C2 (C2SH) results in loss of ipsilateral rhythmic diaphragm muscle (DIAm) EMG activity associated with lower force behaviors accomplished by recruitment of smaller PhMNs that recovers over time in rats. Activity during higher force, non-ventilatory behaviors that recruit larger PhMNs is minimally impaired following C2SH. We previously showed neuroplasticity in glutamatergic receptor expression in PhMN post-C2SH with changes in NMDA receptor expression reflecting functional recovery. We hypothesize that C2SH-induced changes in glutamatergic receptor (AMPA and NMDA) mRNA expression in PhMNs vary with motor neuron size, with more pronounced changes in smaller PhMNs. Retrogradely-labelled PhMNs were classified in tertiles according to somal surface area and mRNA expression was measured using single-cell, multiplex fluorescence in situ hybridization. Ipsilateral to C2SH, a pronounced reduction in NMDA mRNA expression in PhMNs was evident at 3 days post-injury with similar impact on PhMNs in the lower size tertile (~68% reduction) and upper tertile (~60%); by 21DSH, there was near complete restoration of NMDA receptor mRNA expression across all PhMNs. There were no changes in NMDA mRNA expression contralateral to C2SH. There were no changes in AMPA mRNA expression at PhMNs on either side of the spinal cord or at any time-point post-C2SH. In summary, following C2SH there is ipsilateral reduction in PhMN NMDA mRNA expression at 3DSH that is not limited to smaller PhMN recruited in the generation of lower force ventilatory behaviors. The recovery of NMDA mRNA expression by 21DSH is consistent with evidence of spontaneous recovery of ipsilateral DIAm activity at this timepoint. These findings suggest a possible role for NMDA receptor mediated glutamatergic signaling in mechanisms supporting postsynaptic neuroplasticity at the PhMN pool and recovery of DIAm activity after cervical SCI.
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Fragiotta S, Costanzo E, Viggiano P, De Geronimo D, Scuderi G, Varano M, Parravano M. Functional Correlates of Outer Retina Remodeling in Intermediate Age-Related Macular Degeneration Using Microperimetry. Invest Ophthalmol Vis Sci 2022; 63:16. [PMID: 35289843 PMCID: PMC8934566 DOI: 10.1167/iovs.63.3.16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To assess the effect of drusen morphometric changes and choroidal vascular modifications on retinal sensitivity (RS) evaluated through microperimetry in intermediate age-related macular degeneration (iAMD). Methods A retrospective review of 18 iAMD patients (18 eyes) with a 12-month follow-up was performed. Eye-tracked spectral-domain optical coherence tomography was obtained, with automatic segmentation of the outer retinal layer (ORL) delineating the drusen area from the external limiting membrane to Bruch's membrane and outer nuclear layer (ONL) thickness maps adjusted manually, as needed. Advanced retinal pigment epithelium analysis was also performed with a ZEISS PLEX Elite 900. Microperimetry obtained under mesopic conditions was overlaid with the corresponding thickness maps with Fiji software. The choroidal vascularity index (CVI) was calculated in the subfoveal b-scan and volumetric in the central 1-mm subfield. Results A reduced central ONL thickness was strongly associated with RS decline at the same region (r = 0.69, P = 0.002) and globally (r = 0.80, P < 0.001) at baseline, but also at 1 year in the central subfield (central: r = 0.70, P = 0.001). One-year subfoveal CVI variation, differently from volumetric CVI, directly influenced the central (r = 0.64, P = 0.004) and global RS (r = 0.59, P = 0.009), indicating that a CVI reduction negatively affected RS. A greater volumetric CVI within central 1-mm was associated with ORL thickening at 1 year (r = 0.61, P = 0.008). Conclusions Progressive degeneration of the ONL is related to irreversible photoreceptor dysfunction in iAMD. Likewise, choroidal vascular modifications are associated with a significant functional decline in the central region and diffusely.
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Affiliation(s)
- Serena Fragiotta
- Ophthalmology Unit, "Sapienza" University of Rome, NESMOS Department, St. Andrea Hospital, Rome, Italy
| | | | | | | | - Gianluca Scuderi
- Ophthalmology Unit, "Sapienza" University of Rome, NESMOS Department, St. Andrea Hospital, Rome, Italy
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12
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Mitochondrial morphology and function varies across diaphragm muscle fiber types. Respir Physiol Neurobiol 2022; 295:103780. [PMID: 34478909 PMCID: PMC8604766 DOI: 10.1016/j.resp.2021.103780] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/26/2021] [Accepted: 08/29/2021] [Indexed: 01/03/2023]
Abstract
In diaphragm muscle (DIAm), type I and IIa fibers are recruited to accomplish breathing, while type IIx/IIb fibers are recruited only during expulsive/straining behaviors. Thus, type I and IIa DIAm fibers are much more active (duty cycle of ∼40 %) than type IIx/IIb fibers (duty cycle of <1%), which we hypothesized underlies intrinsic differences in mitochondrial structure and function. MitoTracker Green labeled mitochondria were imaged in 3-D using confocal microscopy. Mitochondrial volume density (MVD, per muscle fiber volume) was higher, and mitochondria were more filamentous in type I and IIa DIAm compared to type IIx/IIb fibers. The maximum velocity of the succinate dehydrogenase reaction (SDHmax), measured using a quantitative histochemical technique was found to be higher in type I and IIa DIAm fibers compared to type IIx/IIb fibers with and without normalizing for MVD. These results are consistent with fiber type differences in the intrinsic structural and functional properties of DIAm fibers and closely match differences in energetic demands.
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13
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Gribaudo S, Saraulli D, Nato G, Bonzano S, Gambarotta G, Luzzati F, Costanzi M, Peretto P, Bovetti S, De Marchis S. Neurogranin Regulates Adult-Born Olfactory Granule Cell Spine Density and Odor-Reward Associative Memory in Mice. Int J Mol Sci 2021; 22:ijms22084269. [PMID: 33924098 PMCID: PMC8074334 DOI: 10.3390/ijms22084269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 11/16/2022] Open
Abstract
Neurogranin (Ng) is a brain-specific postsynaptic protein, whose role in modulating Ca2+/calmodulin signaling in glutamatergic neurons has been linked to enhancement in synaptic plasticity and cognitive functions. Accordingly, Ng knock-out (Ng-ko) mice display hippocampal-dependent learning and memory impairments associated with a deficit in long-term potentiation induction. In the adult olfactory bulb (OB), Ng is expressed by a large population of GABAergic granule cells (GCs) that are continuously generated during adult life, undergo high synaptic remodeling in response to the sensory context, and play a key role in odor processing. However, the possible implication of Ng in OB plasticity and function is yet to be investigated. Here, we show that Ng expression in the OB is associated with the mature state of adult-born GCs, where its active-phosphorylated form is concentrated at post-synaptic sites. Constitutive loss of Ng in Ng-ko mice resulted in defective spine density in adult-born GCs, while their survival remained unaltered. Moreover, Ng-ko mice show an impaired odor-reward associative memory coupled with reduced expression of the activity-dependent transcription factor Zif268 in olfactory GCs. Overall, our data support a role for Ng in the molecular mechanisms underlying GC plasticity and the formation of olfactory associative memory.
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Affiliation(s)
- Simona Gribaudo
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
| | - Daniele Saraulli
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council, 00143 Rome, Italy;
| | - Giulia Nato
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
| | - Sara Bonzano
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
| | - Giovanna Gambarotta
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
- Department of Clinical and Biological Sciences (DSCB), University of Torino, 10043 Turin, Italy
| | - Federico Luzzati
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
| | - Marco Costanzi
- Department of Human Sciences, LUMSA University, 00193 Rome, Italy;
| | - Paolo Peretto
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
| | - Serena Bovetti
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
- Correspondence: (S.B.); (S.D.M.)
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
- Correspondence: (S.B.); (S.D.M.)
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14
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Fogarty MJ, Rana S, Mantilla CB, Sieck GC. Quantifying mitochondrial volume density in phrenic motor neurons. J Neurosci Methods 2021; 353:109093. [PMID: 33549636 PMCID: PMC7990712 DOI: 10.1016/j.jneumeth.2021.109093] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 12/31/2022]
Abstract
BACKGROUND Previous assessments of mitochondrial volume density within motor neurons used electron microscopy (EM) to image mitochondria. However, adequate identification and sampling of motor neurons within a particular motor neuron pool is largely precluded using EM. Here, we present an alternative method for determining mitochondrial volume density in identified motor neurons within the phrenic motor neuron (PhMN) pool, with greatly increased sampling. NEW METHOD This novel method for assessing mitochondrial volume density in PhMNs uses a combination of intrapleural injection of Alexa 488-conjugated cholera toxin B (CTB) to retrogradely label PhMNs, followed by intrathecal application of MitoTracker Red to label mitochondria. This technique was validated by comparison to 3D EM determination of mitochondrial volume density as a "gold standard". RESULTS A mean mitochondrial volume density of ∼11 % was observed across PhMNs using the new MitoTracker Red method. This compared favourably with mitochondrial volume density (∼11 %) measurements using EM. COMPARISON WITH EXISTING METHOD The range, mean and variance of mitochondrial volume density estimates in PhMNs were not different between EM and fluorescent imaging techniques. CONCLUSIONS Fluorescent imaging may be used to estimate mitochondrial volume density in a large sample of motor neurons, with results similar to EM, although EM did distinguish finer mitochondrion morphology compared to MitoTracker fluorescence. Compared to EM methods, the assessment of a larger sample size and unambiguous identification of motor neurons belonging to a specific motor neuron pool represent major advantages over previous methods.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States; School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Sabhya Rana
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States
| | - Carlos B Mantilla
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States; Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, 55905, United States
| | - Gary C Sieck
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States.
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15
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Miura M, Makita S, Yasuno Y, Iwasaki T, Azuma S, Mino T, Yamaguchi T. Evaluation of retinal pigment epithelium changes in serous pigment epithelial detachment in age-related macular degeneration. Sci Rep 2021; 11:2764. [PMID: 33531591 PMCID: PMC7854605 DOI: 10.1038/s41598-021-82563-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 01/21/2021] [Indexed: 11/28/2022] Open
Abstract
The purpose of this study was to quantitatively evaluate retinal pigment epithelium (RPE) changes in serous pigment epithelial detachment (PED) among patients with age-related macular degeneration by means of prototype multi-contrast optical coherence tomography (OCT), which is capable of simultaneous collection of OCT angiography, polarization-sensitive OCT, and standard OCT images. We evaluated 26 eyes of 21 patients with serous PED. RPE-melanin OCT images were calculated from the multi-contrast OCT dataset and compared with near-infrared autofluorescence images. An active RPE lesion was defined as an area of thickened RPE-melanin (≥ 70 μm; RPE70) on RPE-melanin OCT. Each PED area was divided into peak and slope regions. RPE70 area ratios were compared with the maximum PED height, PED area, PED volume, and slope area ratio (area of slope region/area of whole PED). RPE-melanin OCT images were consistent with near-infrared autofluorescence images. The RPE70 area ratio in the slope region was significantly negatively correlated with the slope area ratio. Development of active RPE lesions in the slope region was correlated with the PED configuration. Multi-contrast OCT is useful for objective evaluation of changes in the RPE in patients with age-related macular degeneration.
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Affiliation(s)
- Masahiro Miura
- Department of Ophthalmology, Tokyo Medical University, Ibaraki Medical Center, 3-20-1 Chuo, Ami, Inashiki, Ibaraki, 300395, Japan.
| | - Shuichi Makita
- Computational Optics Group, University of Tsukuba, Tsukuba, Japan
| | - Yoshiaki Yasuno
- Computational Optics Group, University of Tsukuba, Tsukuba, Japan
| | - Takuya Iwasaki
- Department of Ophthalmology, Tokyo Medical University, Ibaraki Medical Center, 3-20-1 Chuo, Ami, Inashiki, Ibaraki, 300395, Japan
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16
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Trova S, Bovetti S, Pellegrino G, Bonzano S, Giacobini P, Peretto P. HPG-Dependent Peri-Pubertal Regulation of Adult Neurogenesis in Mice. Front Neuroanat 2020; 14:584493. [PMID: 33328903 PMCID: PMC7732626 DOI: 10.3389/fnana.2020.584493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/29/2020] [Indexed: 11/13/2022] Open
Abstract
Adult neurogenesis, a striking form of neural plasticity, is involved in the modulation of social stimuli driving reproduction. Previous studies on adult neurogenesis have shown that this process is significantly modulated around puberty in female mice. Puberty is a critical developmental period triggered by increased secretion of the gonadotropin releasing hormone (GnRH), which controls the activity of the hypothalamic-pituitary-gonadal axis (HPG). Secretion of HPG-axis factors at puberty participates to the refinement of neural circuits that govern reproduction. Here, by exploiting a transgenic GnRH deficient mouse model, that progressively loses GnRH expression during postnatal development (GnRH::Cre;Dicer loxP/loxP mice), we found that a postnatally-acquired dysfunction in the GnRH system affects adult neurogenesis selectively in the subventricular-zone neurogenic niche in a sexually dimorphic way. Moreover, by examining adult females ovariectomized before the onset of puberty, we provide important evidence that, among the HPG-axis secreting factors, the circulating levels of gonadal hormones during pre-/peri-pubertal life contribute to set-up the proper adult subventricular zone-olfactory bulb neurogenic system.
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Affiliation(s)
- Sara Trova
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy.,Univ.Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience and Cognition, Laboratory of the Development and Plasticity of Neuroendocrine Brain, Lille, France
| | - Serena Bovetti
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
| | - Giuliana Pellegrino
- Univ.Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience and Cognition, Laboratory of the Development and Plasticity of Neuroendocrine Brain, Lille, France
| | - Sara Bonzano
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
| | - Paolo Giacobini
- Univ.Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience and Cognition, Laboratory of the Development and Plasticity of Neuroendocrine Brain, Lille, France
| | - Paolo Peretto
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
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17
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Rana S, Zhan WZ, Mantilla CB, Sieck GC. Disproportionate loss of excitatory inputs to smaller phrenic motor neurons following cervical spinal hemisection. J Physiol 2020; 598:4693-4711. [PMID: 32735344 DOI: 10.1113/jp280130] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/20/2020] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS Motor units, comprising a motor neuron and the muscle fibre it innervates, are activated in an orderly fashion to provide varying amounts of force. A unilateral C2 spinal hemisection (C2SH) disrupts predominant excitatory input from medulla, causing cessation of inspiratory-related diaphragm muscle activity, whereas higher force, non-ventilatory diaphragm activity persists. In this study, we show a disproportionately larger loss of excitatory glutamatergic innervation to small phrenic motor neurons (PhMNs) following C2SH, as compared with large PhMNs ipsilateral to injury. Our data suggest that there is a dichotomy in the distribution of inspiratory-related descending excitatory glutamatergic input to small vs. large PhMNs that reflects their differential recruitment. ABSTRACT Excitatory glutamatergic input mediating inspiratory drive to phrenic motor neurons (PhMNs) emanates primarily from the ipsilateral ventrolateral medulla. Unilateral C2 hemisection (C2SH) disrupts this excitatory input, resulting in cessation of inspiratory-related diaphragm muscle (DIAm) activity. In contrast, after C2SH, higher force, non-ventilatory DIAm activity persists. Inspiratory behaviours require recruitment of only smaller PhMNs, whereas with more forceful expulsive/straining behaviours, larger PhMNs are recruited. Accordingly, we hypothesize that C2SH primarily disrupts glutamatergic synaptic inputs to smaller PhMNs, whereas glutamatergic synaptic inputs to larger PhMNs are preserved. We examined changes in glutamatergic presynaptic input onto retrogradely labelled PhMNs using immunohistochemistry for VGLUT1 and VGLUT2. We found that 7 days after C2SH there was an ∼60% reduction in glutamatergic inputs to smaller PhMNs compared with an ∼35% reduction at larger PhMNs. These results are consistent with a more pronounced impact of C2SH on inspiratory behaviours of the DIAm, and the preservation of higher force behaviours after C2SH. These results indicate that the source of glutamatergic synaptic input to PhMNs varies depending on motor neuron size and reflects different functional control - perhaps separate central pattern generator and premotor circuits. For smaller PhMNs, the central pattern generator for inspiration is located in the pre-Bötzinger complex and premotor neurons in the ventrolateral medulla, sending predominantly ipsilateral projections via the dorsolateral funiculus. C2SH disrupts this glutamatergic input. For larger PhMNs, a large proportion of excitatory inputs appear to exist below the C2 level or from contralateral regions of the brainstem and spinal cord.
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Affiliation(s)
- Sabhya Rana
- Departments of Physiology & Biomedical Engineering and
| | - Wen-Zhi Zhan
- Departments of Physiology & Biomedical Engineering and
| | - Carlos B Mantilla
- Departments of Physiology & Biomedical Engineering and.,Anaesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN
| | - Gary C Sieck
- Departments of Physiology & Biomedical Engineering and.,Anaesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN
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18
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Vanhecke D, Crippa F, Lattuada M, Balog S, Rothen-Rutishauser B, Petri-Fink A. Characterization of the Shape Anisotropy of Superparamagnetic Iron Oxide Nanoparticles during Thermal Decomposition. MATERIALS 2020; 13:ma13092018. [PMID: 32344889 PMCID: PMC7254344 DOI: 10.3390/ma13092018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/22/2020] [Accepted: 04/22/2020] [Indexed: 12/30/2022]
Abstract
Magnetosomes are near-perfect intracellular magnetite nanocrystals found in magnetotactic bacteria. Their synthetic imitation, known as superparamagnetic iron oxide nanoparticles (SPIONs), have found applications in a variety of (nano)medicinal fields such as magnetic resonance imaging contrast agents, multimodal imaging and drug carriers. In order to perform these functions in medicine, shape and size control of the SPIONs is vital. We sampled SPIONs at ten-minutes intervals during the high-temperature thermal decomposition reaction. Their shape (sphericity and anisotropy) and geometric description (volume and surface area) were retrieved using three-dimensional imaging techniques, which allowed to reconstruct each particle in three dimensions, followed by stereological quantification methods. The results, supported by small angle X-ray scattering characterization, reveal that SPIONs initially have a spherical shape, then grow increasingly asymmetric and irregular. A high heterogeneity in volume at the initial stages makes place for lower particle volume dispersity at later stages. The SPIONs settled into a preferred orientation on the support used for transmission electron microscopy imaging, which hides the extent of their anisotropic nature in the axial dimension, there by biasing the interpretation of standard 2D micrographs. This information could be feedback into the design of the chemical processes and the characterization strategies to improve the current applications of SPIONs in nanomedicine.
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Affiliation(s)
- Dimitri Vanhecke
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Federica Crippa
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Marco Lattuada
- Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
| | - Sandor Balog
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | | | - Alke Petri-Fink
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
- Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
- Correspondence: ; Tel.: +41-(0)-26-300-9501
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19
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Brandenburg JE, Fogarty MJ, Brown AD, Sieck GC. Phrenic motor neuron loss in an animal model of early onset hypertonia. J Neurophysiol 2020; 123:1682-1690. [PMID: 32233911 DOI: 10.1152/jn.00026.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Phrenic motor neuron (PhMN) development in early onset hypertonia is poorly understood. Respiratory disorders are one of the leading causes of morbidity and mortality in individuals with early onset hypertonia, such as cerebral palsy (CP), but they are largely overshadowed by a focus on physical function in this condition. Furthermore, while the brain is the focus of CP research, motor neurons, via the motor unit and neurotransmitter signaling, are the targets in clinical interventions for hypertonia. Furthermore, critical periods of spinal cord and motor unit development also coincide with the timing that the supposed brain injury occurs in CP. Using an animal model of early-onset spasticity (spa mouse [B6.Cg-Glrbspa/J] with a glycine receptor mutation), we hypothesized that removal of effective glycinergic neurotransmitter inputs to PhMNs during development will result in fewer PhMNs and reduced PhMN somal size at maturity. Adult spa (Glrb-/-), and wild-type (Glrb+/+) mice underwent unilateral retrograde labeling of PhMNs via phrenic nerve dip in tetramethylrhodamine. After three days, mice were euthanized, perfused with 4% paraformaldehyde, and the spinal cord excised and processed for confocal imaging. Spa mice had ~30% fewer PhMNs (P = 0.005), disproportionately affecting larger PhMNs. Additionally, a ~22% reduction in PhMN somal surface area (P = 0.019), an 18% increase in primary dendrites (P < 0.0001), and 24% decrease in dendritic surface area (P = 0.014) were observed. Thus, there are fewer larger PhMNs in spa mice. Fewer and smaller PhMNs may contribute to impaired diaphragm neuromotor control and contribute to respiratory morbidity and mortality in conditions of early onset hypertonia.NEW & NOTEWORTHY Phrenic motor neuron (PhMN) development in early-onset hypertonia is poorly understood. Yet, respiratory disorders are a common cause of morbidity and mortality. In spa mice, an animal model of early-onset hypertonia, we found ~30% fewer PhMNs, compared with controls. This PhMN loss disproportionately affected larger PhMNs. Thus, the number and heterogeneity of the PhMN pool are decreased in spa mice, likely contributing to the hypertonia, impaired neuromotor control, and respiratory disorders.
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Affiliation(s)
- Joline E Brandenburg
- Department of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Rochester, Minnesota.,Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota.,School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Alyssa D Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Gary C Sieck
- Department of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
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20
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Rana S, Sieck GC, Mantilla CB. Heterogeneous glutamatergic receptor mRNA expression across phrenic motor neurons in rats. J Neurochem 2019; 153:586-598. [PMID: 31563147 DOI: 10.1111/jnc.14881] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/16/2019] [Accepted: 09/23/2019] [Indexed: 12/12/2022]
Abstract
The diaphragm muscle comprises various types of motor units that are recruited in an orderly fashion governed by the intrinsic electrophysiological properties (membrane capacitance as a function of somal surface area) of phrenic motor neurons (PhMNs). Glutamate is the main excitatory neurotransmitter at PhMNs and acts primarily via fast acting AMPA and N-methyl-D-aspartic acid (NMDA) receptors. Differences in receptor expression may also contribute to motor unit recruitment order. We used single cell, multiplex fluorescence in situ hybridization to determine glutamatergic receptor mRNA expression across PhMNs based on their somal surface area. In adult male and female rats (n = 9) PhMNs were retrogradely labeled for analyses (n = 453 neurons). Differences in the total number and density of mRNA transcripts were evident across PhMNs grouped into tertiles according to somal surface area. A ~ 25% higher density of AMPA (Gria2) and NMDA (Grin1) mRNA expression was evident in PhMNs in the lower tertile compared to the upper tertile. These smaller PhMNs likely comprise type S motor units that are recruited first to accomplish lower force, ventilatory behaviors. In contrast, larger PhMNs with lower volume densities of AMPA and NMDA mRNA expression presumably comprise type FInt and FF motor units that are recruited during higher force, expulsive behaviors. Furthermore, there was a significantly higher cytosolic NMDA mRNA expression in small PhMNs suggesting a more important role for NMDA-mediated glutamatergic neurotransmission at smaller PhMNs. These results are consistent with the observed order of motor unit recruitment and suggest a role for glutamatergic receptors in support of this orderly recruitment. Cover Image for this issue: doi: 10.1111/jnc.14747.
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Affiliation(s)
- Sabhya Rana
- Departments of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Gary C Sieck
- Departments of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA.,Departments of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Carlos B Mantilla
- Departments of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA.,Departments of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
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21
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Rana S, Mantilla CB, Sieck GC. Glutamatergic input varies with phrenic motor neuron size. J Neurophysiol 2019; 122:1518-1529. [PMID: 31389739 DOI: 10.1152/jn.00430.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Like all skeletal muscles, the diaphragm muscle accomplishes a range of motor behaviors by recruiting different motor unit types in an orderly fashion. Recruitment of phrenic motor neurons (PhMNs) is generally assumed to be based primarily on the intrinsic properties of PhMNs with an equal distribution of descending excitatory inputs to all PhMNs. However, differences in presynaptic excitatory input across PhMNs of varying sizes could also contribute to the orderly recruitment pattern. In the spinal cord of Sprague-Dawley rats, we retrogradely labeled PhMNs using cholera toxin B (CTB) and validated a robust confocal imaging-based technique that utilizes semiautomated processing to identify presynaptic glutamatergic (Glu) terminals within a defined distance around the somal membrane of PhMNs of varying size. Our results revealed an ~10% higher density of Glu terminals at PhMNs in the lower tertile of somal surface area. These smaller PhMNs are likely recruited first to accomplish lower force ventilatory behaviors of the diaphragm as compared with larger PhMNs in the upper tertile that are recruited to accomplish higher force expulsive behaviors. These results suggest that differences in excitatory synaptic input to PhMNs may also contribute to the orderly recruitment of diaphragm motor units.NEW & NOTEWORTHY The distribution of excitatory glutamatergic synaptic input to phrenic motor neurons differs across motor neurons of varying size. These findings support the size principle of motor unit recruitment that underlies graded force generation in a muscle, which is based on intrinsic electrophysiological properties of motor neurons resulting from differences in somal surface area. A higher density of glutamatergic inputs at smaller, more excitable motor neurons substantiates the earlier and more frequent recruitment of these units.
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Affiliation(s)
- Sabhya Rana
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Carlos B Mantilla
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
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22
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Evaluation of focal damage in the retinal pigment epithelium layer in serous retinal pigment epithelium detachment. Sci Rep 2019; 9:3278. [PMID: 30824736 PMCID: PMC6397318 DOI: 10.1038/s41598-019-39688-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 01/28/2019] [Indexed: 11/28/2022] Open
Abstract
The purpose of this study was to evaluate focal damage in the retinal pigment epithelium (RPE) layer in serous retinal pigment epithelium detachment (PED) with multi-contrast optical coherence tomography (OCT), which is capable of simultaneous measurement of OCT angiography, polarization-sensitive OCT and standard OCT images. We evaluated 37 eyes with age-related macular degeneration that had serous PED. Focal RPE damage was indicated by hyper-transmission beneath the RPE-Bruch’s membrane band in standard OCT images. Distribution of RPE melanin was calculated using the dataset from multi-contrast OCT. Twenty-four points with hyper-transmission were detected in 21 of the 37 eyes. Standard OCT images failed to show disruption of the RPE-Bruch’s membrane band at 5 of the 24 hyper-transmission points. Conversely, multi-contrast OCT images clearly showed melanin defects in the RPE-Bruch’s membrane band at all points. Areas of melanin defects with disruption of the RPE-Bruch’s membrane band were significantly larger than those without disruption. The volume of intraretinal hyper-reflective foci was significantly larger in eyes with hyper-transmission than that in eyes without hyper-transmission. Multi-contrast OCT is more sensitive than standard OCT for displaying changes at the RPE-Bruch’s membrane band when there are small areas of RPE damage.
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Cell Kinetics in the Adult Neurogenic Niche and Impact of Diet-Induced Accelerated Aging. J Neurosci 2019; 39:2810-2822. [PMID: 30737307 PMCID: PMC6462444 DOI: 10.1523/jneurosci.2730-18.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/21/2018] [Accepted: 01/31/2019] [Indexed: 01/08/2023] Open
Abstract
Neurogenesis in the adult brain, a powerful mechanism for neuronal plasticity and brain repair, is altered by aging and pathological conditions, including metabolic disorders. The search for mechanisms and therapeutic solutions to alter neurogenesis requires understanding of cell kinetics within neurogenic niches using a high-throughput quantitative approach. The challenge is in the dynamic nature of the process and multiple cell types involved, each having several potential modes of division or cell fate. Here we show that cell kinetics can be revealed through a combination of the BrdU/EdU pulse-chase, based on the circadian pattern of DNA replication, and a differential equations model that describes time-dependent cell densities. The model is validated through the analysis of cell kinetics in the cerebellar neurogenic niche of normal young adult male zebrafish, with cells quantified in 2D (sections), and with neuronal fate and reactivation of stem cells confirmed in 3D whole-brain images (CLARITY). We then reveal complex alterations in cell kinetics associated with accelerated aging due to chronic high caloric intake. Low activity of neuronal stem cells in this condition persists 2 months after reverting to normal diet, and is accompanied by overproduction of transient amplifying cells, their accelerated cell death, and slow migration of postmitotic progeny. This combined experimental and mathematical approach should allow for relatively high-throughput analysis of early signs of pathological and age-related changes in neurogenesis, evaluation of specific therapeutic targets, and drug efficacy.SIGNIFICANCE STATEMENT Understanding normal cell kinetics of adult neurogenesis and the type of cells affected by a pathological process is needed to develop effective prophylactic and therapeutic measures directed at specific cell targets. Complex time-dependent mechanisms involved in the kinetics of multiple cell types require a combination of experimental and mathematical modeling approaches. This study demonstrates such a combined approach by comparing normal neurogenesis with that altered by diet-induced accelerated aging in adult zebrafish.
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Intermittent Hypoxia Disrupts Adult Neurogenesis and Synaptic Plasticity in the Dentate Gyrus. J Neurosci 2018; 39:1320-1331. [PMID: 30587544 DOI: 10.1523/jneurosci.1359-18.2018] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 09/03/2018] [Accepted: 09/27/2018] [Indexed: 01/06/2023] Open
Abstract
Individuals with sleep apnea often exhibit changes in cognitive behaviors consistent with alterations in the hippocampus. It is hypothesized that adult neurogenesis in the dentate gyrus is an ongoing process that maintains normal hippocampal function in many mammalian species, including humans. However, the impact of chronic intermittent hypoxia (IH), a principal consequence of sleep apnea, on hippocampal adult neurogenesis remains unclear. Using a murine model, we examined the impact of 30 d of IH (IH30) on adult neurogenesis and synaptic plasticity in the dentate gyrus. Although IH30 did not affect paired-pulse facilitation, IH30 suppressed long-term potentiation (LTP). Immunohistochemical experiments also indicate that IH perturbs multiple aspects of adult neurogenesis. IH30 increased the number of proliferating Sox2+ neural progenitor cells in the subgranular zone yet reduced the number of doublecortin-positive neurons. Consistent with these findings, cell lineage tracing revealed that IH30 increased the proportion of radial glial cells in the subgranular zone, yet decreased the proportion of adult-born neurons in the dentate gyrus. While administration of a superoxide anion scavenger during IH did not prevent neural progenitor cell proliferation, it mitigated the IH-dependent suppression of LTP and prevented adult-born neuron loss. These data demonstrate that IH causes both reactive oxygen species-dependent and reactive oxygen species-independent effects on adult neurogenesis and synaptic plasticity in the dentate gyrus. Our findings identify cellular and neurophysiological changes in the hippocampus that may contribute to cognitive and behavioral deficits occurring in sleep apnea.SIGNIFICANCE STATEMENT Individuals with sleep apnea experience periods of intermittent hypoxia (IH) that can negatively impact many aspects of brain function. Neurons are continually generated throughout adulthood to support hippocampal physiology and behavior. This study demonstrates that IH exposure attenuates hippocampal long-term potentiation and reduces adult neurogenesis. Antioxidant treatment mitigates these effects indicating that oxidative signaling caused by IH is a significant factor that impairs synaptic plasticity and reduces adult neurogenesis in the hippocampus.
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25
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Mbanga B, van Dyk C, Maina JN. Morphometric and morphological study of the respiratory organs of the bimodally-breathing African sharptooth catfish (Clarias gariepinus): Burchell (1822). ZOOLOGY 2018; 130:6-18. [PMID: 30502840 DOI: 10.1016/j.zool.2018.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 12/01/2022]
Abstract
The respiratory organs of the African sharptooth catfish, Clarias gariepinus, were studied to broaden existing understanding of the adaptive stratagems that have evolved for air-breathing in fish. The gills were well-developed and the air-breathing organs (ABOs) comprised labyrinthine organs (LOs), suprabranchial chamber membranes (SBCMs) and gill fans (GFns). Respectively, the gills and the LOs had the highest mass-specific respiratory surface areas of 133.7 and 141.9 mm2 per gram and among the ABOs, with a harmonic mean thickness of the blood-barrier (BGB) of 0.39 μm, the LOs had the thinnest BGB followed by the GFns (0.48 μm) and the SBCMs (0.49 μm): the water-blood barrier of the gills was relatively much thicker (7.93 μm). Vindicating why C. gariepinus is an obligate air-breather, the total mass-specific morphometric (anatomical) diffusing capacity of the ABOs for O2 per unit body weight (W) (Dto2/W) comprised 90.5% of the mean total value for all the respiratory organs. Compared with the East African catfish, Clarias mossambicus, the Dto2/W of the ABOs of C. gariepinus was 5.7 times greater. The difference between the two species of fish may be explained by the physicochemical differences of the aquatic habitats they occupy: the former occupies a seasonal river which dries up during the summer months leaving shallow pools of water in which the O2 concentrations are very low and CO2 very high while the later populates a highly eutrophic dam where the O2 levels greatly fluctuate seasonally.
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Affiliation(s)
- Blandine Mbanga
- Department of Zoology, University of Johannesburg, Auckland Park Campus 2006, Kingsway, Johannesburg, South Africa
| | - Cobus van Dyk
- Department of Zoology, University of Johannesburg, Auckland Park Campus 2006, Kingsway, Johannesburg, South Africa
| | - John N Maina
- Department of Zoology, University of Johannesburg, Auckland Park Campus 2006, Kingsway, Johannesburg, South Africa.
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26
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Mantilla CB, Zhan WZ, Gransee HM, Prakash YS, Sieck GC. Phrenic motoneuron structural plasticity across models of diaphragm muscle paralysis. J Comp Neurol 2018; 526:2973-2983. [PMID: 30411341 DOI: 10.1002/cne.24503] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/09/2018] [Indexed: 12/19/2022]
Abstract
Structural plasticity in motoneurons may be influenced by activation history and motoneuron-muscle fiber interactions. The goal of this study was to examine the morphological adaptations of phrenic motoneurons following imposed motoneuron inactivity while controlling for diaphragm muscle inactivity. Well-characterized rat models were used including unilateral C2 spinal hemisection (SH; ipsilateral phrenic motoneurons and diaphragm muscle are inactive) and tetrodotoxin phrenic nerve blockade (TTX; ipsilateral diaphragm muscle is paralyzed while phrenic motoneuron activity is preserved). We hypothesized that inactivity of phrenic motoneurons would result in a decrease in motoneuron size, consistent with a homeostatic increase in excitability. Phrenic motoneurons were retrogradely labeled by ipsilateral diaphragm muscle injection of fluorescent dextrans or cholera toxin subunit B. Following 2 weeks of diaphragm muscle paralysis, morphological parameters of labeled ipsilateral phrenic motoneurons were assessed quantitatively using fluorescence confocal microscopy. Compared to controls, phrenic motoneuron somal volumes and surface areas decreased with SH, but increased with TTX. Total phrenic motoneuron surface area was unchanged by SH, but increased with TTX. Dendritic surface area was estimated from primary dendrite diameter using a power equation obtained from three-dimensional reconstructed phrenic motoneurons. Estimated dendritic surface area was not significantly different between control and SH, but increased with TTX. Similarly, TTX significantly increased total phrenic motoneuron surface area. These results suggest that ipsilateral phrenic motoneuron morphological adaptations are consistent with a normalization of motoneuron excitability following prolonged alterations in motoneuron activity. Phrenic motoneuron structural plasticity is likely more dependent on motoneuron activity (or descending input) than muscle fiber activity.
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Affiliation(s)
- Carlos B Mantilla
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota.,Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Wen-Zhi Zhan
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Heather M Gransee
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Y S Prakash
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota.,Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Gary C Sieck
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota.,Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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27
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Brandenburg JE, Gransee HM, Fogarty MJ, Sieck GC. Differences in lumbar motor neuron pruning in an animal model of early onset spasticity. J Neurophysiol 2018; 120:601-609. [PMID: 29718808 DOI: 10.1152/jn.00186.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Motor neuron (MN) development in early onset spasticity is poorly understood. For example, spastic cerebral palsy (sCP), the most common motor disability of childhood, is poorly predicted by brain imaging, yet research remains focused on the brain. By contrast, MNs, via the motor unit and neurotransmitter signaling, are the target of most therapeutic spasticity treatments and are the final common output of motor control. MN development in sCP is a critical knowledge gap, because the late embryonic and postnatal periods are not only when the supposed brain injury occurs but also are critical times for spinal cord neuromotor development. Using an animal model of early onset spasticity [ spa mouse (B6.Cg- Glrbspa/J) with a glycine (Gly) receptor mutation], we hypothesized that removal of effective glycinergic neurotransmitter inputs to MNs during development will influence MN pruning (including primary dendrites) and MN size. Spa (Glrb-/-) and wild-type (Glrb+/+) mice, ages 4-9 wk, underwent unilateral retrograde labeling of the tibialis anterior muscle MNs via peroneal nerve dip in tetramethylrhodamine. After 3 days, mice were euthanized and perfused with 4% paraformaldehyde, and the spinal cord was excised and processed for confocal imaging. Spa mice had ~61% fewer lumbar tibialis anterior MNs ( P < 0.01), disproportionately affecting larger MNs. Additionally, a ~23% reduction in tibialis anterior MN somal surface area ( P < 0.01) and a 12% increase in primary dendrites ( P = 0.046) were observed. Thus MN pruning and MN somal surface area are abnormal in early onset spasticity. Fewer and smaller MNs may contribute to the spastic phenotype. NEW & NOTEWORTHY Motor neuron (MN) development in early onset spasticity is poorly understood. In an animal model of early onset spasticity, spa mice, we found ~61% fewer lumbar tibialis anterior MNs compared with controls. This MN loss disproportionately affected larger MNs. Thus number and heterogeneity of the MN pool are decreased in spa mice, likely contributing to the spastic phenotype.
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Affiliation(s)
- Joline E Brandenburg
- Department of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine , Rochester, Minnesota.,Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine , Rochester, Minnesota
| | - Heather M Gransee
- Department of Anesthesiology, Mayo Clinic College of Medicine , Rochester, Minnesota
| | - Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine , Rochester, Minnesota.,School of Biomedical Sciences, The University of Queensland , Brisbane , Australia
| | - Gary C Sieck
- Department of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine , Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine , Rochester, Minnesota.,Department of Anesthesiology, Mayo Clinic College of Medicine , Rochester, Minnesota
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28
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Malloul H, Bennis M, Bonzano S, Gambarotta G, Perroteau I, De Marchis S, Ba-M'hamed S. Decreased Hippocampal Neuroplasticity and Behavioral Impairment in an Animal Model of Inhalant Abuse. Front Neurosci 2018; 12:35. [PMID: 29472835 PMCID: PMC5810293 DOI: 10.3389/fnins.2018.00035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 01/15/2018] [Indexed: 12/22/2022] Open
Abstract
Thinners are highly toxic chemicals widely employed as organic solvents in industrial and domestic use. They have psychoactive properties when inhaled, and their chronic abuse as inhalants is associated with severe long-term health effects, including brain damage and cognitive-behavioral alterations. Yet, the sites and mechanisms of action of these compounds on the brain are far from being fully understood. Here, we investigated the consequences of paint thinner inhalation in adult male mice. Depression-like behaviors and an anxiolytic effect were found following repeated exposure in chronic treatments lasting 12 weeks. Both subchronic (6 weeks) and chronic treatments impaired learning and memory functions, while no changes were observed after acute treatment. To investigate possible molecular/structural alterations underlying such behavioral changes, we focused on the hippocampus. Notably, prolonged, but not acute thinner inhalation strongly affected adult neurogenesis in the dentate gyrus (DG), reducing progenitor cell proliferation after chronic treatments and impairing the survival of newborn neurons following both chronic and subchronic treatments. Furthermore, a down-regulation in the expression of BDNF and NMDA receptor subunits as well as a reduction in CREB expression/phosphorylation were found in the hippocampi of chronically treated mice. Our findings demonstrate for the first time significant structural and molecular changes in the adult hippocampus after prolonged paint thinner inhalation, indicating reduced hippocampal neuroplasticity and strongly supporting its implication in the behavioral dysfunctions associated to inhalant abuse.
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Affiliation(s)
- Hanaa Malloul
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
| | - Mohammed Bennis
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
| | - Sara Bonzano
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy.,Neuroscience Institute Cavalieri Ottolenghi, Orbassano, Italy
| | - Giovanna Gambarotta
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Italy
| | - Isabelle Perroteau
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Italy
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy.,Neuroscience Institute Cavalieri Ottolenghi, Orbassano, Italy
| | - Saadia Ba-M'hamed
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
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29
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Fogarty MJ, Omar TS, Zhan WZ, Mantilla CB, Sieck GC. Phrenic motor neuron loss in aged rats. J Neurophysiol 2018; 119:1852-1862. [PMID: 29412773 DOI: 10.1152/jn.00868.2017] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Sarcopenia is the age-related reduction of muscle mass and specific force. In previous studies, we found that sarcopenia of the diaphragm muscle (DIAm) is evident by 24 mo of age in both rats and mice and is associated with selective atrophy of type IIx and IIb muscle fibers and a decrease in maximum specific force. These fiber type-specific effects of sarcopenia resemble those induced by DIAm denervation, leading us to hypothesize that sarcopenia is due to an age-related loss of phrenic motor neurons (PhMNs). To address this hypothesis, we determined the number of PhMNs in young (6 mo old) and old (24 mo old) Fischer 344 rats. Moreover, we determined age-related changes in the size of PhMNs, since larger PhMNs innervate type IIx and IIb DIAm fibers. The PhMN pool was retrogradely labeled and imaged with confocal microscopy to assess the number of PhMNs and the morphometry of PhMN soma and proximal dendrites. In older animals, there were 22% fewer PhMNs, a 19% decrease in somal surface area, and a 21% decrease in dendritic surface area compared with young Fischer 344 rats. The age-associated loss of PhMNs involved predominantly larger PhMNs. These results are consistent with an age-related denervation of larger, more fatigable DIAm motor units, which are required primarily for high-force airway clearance behaviors. NEW & NOTEWORTHY Diaphragm muscle sarcopenia in rodent models is well described in the literature; however, the relationship between sarcopenia and frank phrenic motor neuron (MN) loss is unexplored in these models. We quantify a 22% loss of phrenic MNs in old (24 mo) compared with young (6 mo) Fischer 344 rats. We also report reductions in phrenic MN somal and proximal dendritic morphology that relate to decreased MN heterogeneity in old compared with young Fischer 344 rats.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,School of Biomedical Sciences, The University of Queensland , Brisbane , Australia
| | - Tanya S Omar
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Wen-Zhi Zhan
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology, Mayo Clinic College of Medicine , Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology, Mayo Clinic College of Medicine , Rochester, Minnesota
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30
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Stankiewicz AJ, McGowan EM, Yu L, Zhdanova IV. Impaired Sleep, Circadian Rhythms and Neurogenesis in Diet-Induced Premature Aging. Int J Mol Sci 2017; 18:E2243. [PMID: 29072584 PMCID: PMC5713213 DOI: 10.3390/ijms18112243] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/13/2017] [Accepted: 10/22/2017] [Indexed: 01/02/2023] Open
Abstract
Chronic high caloric intake (HCI) is a risk factor for multiple major human disorders, from diabetes to neurodegeneration. Mounting evidence suggests a significant contribution of circadian misalignment and sleep alterations to this phenomenon. An inverse temporal relationship between sleep, activity, food intake, and clock mechanisms in nocturnal and diurnal animals suggests that a search for effective therapeutic approaches can benefit from the use of diurnal animal models. Here, we show that, similar to normal aging, HCI leads to the reduction in daily amplitude of expression for core clock genes, a decline in sleep duration, an increase in scoliosis, and anxiety-like behavior. A remarkable decline in adult neurogenesis in 1-year old HCI animals, amounting to only 21% of that in age-matched Control, exceeds age-dependent decline observed in normal 3-year old zebrafish. This is associated with misalignment or reduced amplitude of daily patterns for principal cell cycle regulators, cyclins A and B, and p20, in brain tissue. Together, these data establish HCI in zebrafish as a model for metabolically induced premature aging of sleep, circadian functions, and adult neurogenesis, allowing for a high throughput approach to mechanistic studies and drug trials in a diurnal vertebrate.
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Affiliation(s)
- Alexander J Stankiewicz
- Department of Preclinical Research and Development, BioChron LLC, Worcester, MA 01605, USA.
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Erin M McGowan
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Lili Yu
- Department of Preclinical Research and Development, BioChron LLC, Worcester, MA 01605, USA.
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Irina V Zhdanova
- Department of Preclinical Research and Development, BioChron LLC, Worcester, MA 01605, USA.
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA.
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31
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Malloul H, Mahdani FM, Bennis M, Ba-M'hamed S. Prenatal Exposure to Paint Thinner Alters Postnatal Development and Behavior in Mice. Front Behav Neurosci 2017; 11:171. [PMID: 28959195 PMCID: PMC5604056 DOI: 10.3389/fnbeh.2017.00171] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 08/29/2017] [Indexed: 01/17/2023] Open
Abstract
Occupational exposure and sniffing of volatile organic solvents continue to be a worldwide health problem, raising the risk for teratogenic sequelae of maternal inhalant abuse. Real life exposures usually involve simultaneous exposures to multiple solvents, and almost all the abused solvents contain a mixture of two or more different volatile compounds. However, several studies examined the teratogenicity due to industrial exposure to a single volatile solvent but investigating the teratogenic potential of complex chemical mixture such as thinner remains unexplored. This study was undertaken to evaluate developmental neurotoxicity of paint thinner using a mouse model. Mated female mice (N = 21) were, therefore, exposed to repeated and brief inhalation episodes of 0, 300 or 600 ppm of thinner during the entire period of pregnancy. Females weigh was recorded and their standard fertility and reproductive parameters were assessed. After birth postnatal day 1 (PND1), offspring (N = 88) length and body weight were measured in a daily basis. At PND5, the pups were assessed for their postnatal growth, physical maturation, reflex development, neuromotor abilities, sensory function, activity level, anxiety, depression, learning and memory functions. At adulthood, structural changes of the hippocampus were examined by estimating the total volume of the dentate gyrus. Except one case of thinner induced abortion at the higher dose, our results showed that the prenatal exposure to the solvent did not cause any maternal toxicity or decrease in the viability of the offspring. Therefore, a lower birth weight, decrease in the litter size and delayed reflexes ontogeny were registered in prenatally exposed offspring to both 300 ppm and 600 ppm of thinner. In addition, prenatally exposure to thinner resulted in increased anxiolytic- and depression-like behaviors. In contrast, impaired learning and memory functions and decreased hippocampal dentate gyrus volume were revealed only in the prenatally treated offspring by 600 ppm of thinner. Based on these results, we can conclude that prenatally exposure to paint thinner causes a long-lasting developmental neurotoxicity and alters a wide range of behavioral functions in mice. This shows the risk that mothers who abuse thinner paint expose their offspring.
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Affiliation(s)
- Hanaa Malloul
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, University Cadi AyyadMarrakech, Morocco
| | - Ferdaousse M Mahdani
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, University Cadi AyyadMarrakech, Morocco
| | - Mohammed Bennis
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, University Cadi AyyadMarrakech, Morocco
| | - Saadia Ba-M'hamed
- Laboratory of Pharmacology, Neurobiology and Behavior (URAC-37), Faculty of Sciences Semlalia, University Cadi AyyadMarrakech, Morocco
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32
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Tan ACS, Astroz P, Dansingani KK, Slakter JS, Yannuzzi LA, Curcio CA, Freund KB. The Evolution of the Plateau, an Optical Coherence Tomography Signature Seen in Geographic Atrophy. Invest Ophthalmol Vis Sci 2017; 58:2349-2358. [PMID: 28437524 PMCID: PMC5413303 DOI: 10.1167/iovs.16-21237] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Purpose Histologic details of progression routes to geographic atrophy (GA) in AMD are becoming available through optical coherence tomography (OCT). We studied the origins and evolution of an OCT signature called plateau in eyes with GA and suggested a histologic correlate. Methods Serial eye-tracked OCT scans and multimodal imaging were acquired from eight eyes of seven patients with GA and plateau signatures over a mean follow-up of 7.7 years (range, 3.7–11.6). The histology of unrelated donor eyes with AMD was reviewed. Results Drusenoid pigment epithelial detachment (PED) on OCT imaging progressed into wide-based mound-like signatures with flattened apices characterized by a hyporeflective yet heterogeneous interior and an overlying hyperreflective exterior, similar to outer retinal corrugations previously ascribed to persistent basal laminar deposit (BLamD) but larger. These new signatures are described as “plateaus.” An initial increase of the PED volume and hyporeflectivity of its contents was followed by a decrease in PED volume and thinning of an overlying hyperreflective band attributable to the loss of the overlying RPE leaving persistent BLamD. Both imaging and histology revealed persistent BLamD with defects through which gliotic Müller cell processes pass. Conclusions Plateaus can be traced back to drusenoid PEDs on OCT imaging. We hypothesize that during progressive RPE atrophy, Müller cell extension through focal defects in the residual persistent BLamD may contribute to the heterogeneous internal reflectivity of these entities. The role of Müller cell activation and extension in the pathogenesis of AMD should be explored in future studies.
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Affiliation(s)
- Anna C S Tan
- Vitreous Retina Macula Consultants of New York, New York, New York, United States 2The LuEsther T. Mertz Retinal Research Center, New York, New York, United States 3Singapore National Eye Center/Singapore Eye Research Institute/Duke-NUS Medical School, Singapore, Singapore
| | - Polina Astroz
- Vitreous Retina Macula Consultants of New York, New York, New York, United States 4Department of Ophthalmology, Intercity Hospital and University Paris Est, Creteil, France
| | - Kunal K Dansingani
- Vitreous Retina Macula Consultants of New York, New York, New York, United States 2The LuEsther T. Mertz Retinal Research Center, New York, New York, United States 5Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Jason S Slakter
- Vitreous Retina Macula Consultants of New York, New York, New York, United States
| | - Lawrence A Yannuzzi
- Vitreous Retina Macula Consultants of New York, New York, New York, United States 2The LuEsther T. Mertz Retinal Research Center, New York, New York, United States
| | - Christine A Curcio
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, Alabama, United States
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, New York, United States 2The LuEsther T. Mertz Retinal Research Center, New York, New York, United States 7Department of Ophthalmology, New York University School of Medicine, New York, New York, United States
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Evaluation of intraretinal migration of retinal pigment epithelial cells in age-related macular degeneration using polarimetric imaging. Sci Rep 2017; 7:3150. [PMID: 28600515 PMCID: PMC5466639 DOI: 10.1038/s41598-017-03529-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/28/2017] [Indexed: 02/07/2023] Open
Abstract
The purpose of the present study was to evaluate the intraretinal migration of the retinal pigment epithelium (RPE) cells in age-related macular degeneration (AMD) using polarimetry. We evaluated 155 eyes at various AMD stages. Depolarized light images were computed using a polarization-sensitive scanning laser ophthalmoscope (PS-SLO), and the degree of polarization uniformity was calculated using polarization-sensitive optical coherence tomography (OCT). Each polarimetry image was compared with the corresponding autofluorescence (AF) images at 488 nm (SW-AF) and at 787 nm (NIR-AF). Intraretinal RPE migration was defined by the presence of depolarization at intraretinal hyperreflective foci on PS-SLO and PS-OCT images, and by the presence of hyper-AF on both NIR-AF and SW-AF images. RPE migration was detected in 52 of 155 eyes (33.5%) and was observed in drusenoid pigment epithelial detachment (PED) and serous PED with significantly higher frequencies than in other groups (P = 0.015). The volume of the migrated RPE cluster in serous PED was significantly correlated with the volume of the PED (R2 = 0.26; P = 0.011). Overall, our results showed that intraretinal RPE migrations occurred in various AMD stages, and that they occurred more commonly in eyes with serous and drusenoid PED.
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34
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Balaratnasingam C, Yannuzzi LA, Curcio CA, Morgan WH, Querques G, Capuano V, Souied E, Jung J, Freund KB. Associations Between Retinal Pigment Epithelium and Drusen Volume Changes During the Lifecycle of Large Drusenoid Pigment Epithelial Detachments. Invest Ophthalmol Vis Sci 2017; 57:5479-5489. [PMID: 27760262 PMCID: PMC5072538 DOI: 10.1167/iovs.16-19816] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Purpose Drusenoid pigment epithelial detachments (PEDs) are a defined path to atrophy in age-related macular degeneration (AMD). We analyzed the relationships between retinal pigment epithelium (RPE) and drusen volume changes during the PED lifecycle, using spectral-domain optical coherence tomography (SD-OCT). Methods Twenty-one cases of drusenoid PED tracked using SD-OCT through periods of growth and collapse were evaluated. Volumetric calculations and piece-wise linear regression analysis were used to determine the breakpoint between growth and collapse. Spectral-domain OCT scans were independently evaluated for the appearance of intraretinal hyperreflective foci, acquired vitelliform lesions (AVLs), and disruptions to the RPE+basal lamina band. Timing of these events with respect to the breakpoint was statistically evaluated. Morphometric characteristics of drusenoid PEDs were correlated with rate of PED collapse and final visual acuity. Results Mean age of subjects was 75.3 years and mean period of follow up was 4.1 years (median 4.5 years; range, 0.6–6.6 years). The lifecycle of drusenoid PEDs was asymmetric, in that the rate of collapse (0.199 mm3/month) is significantly faster (P < 0.001) than the rate of growth (0.022 mm3/month). Appearance of intraretinal hyperreflective foci and AVLs preceded the breakpoint (both P < 0.001). The timing of disruptions to the RPE+basal lamina band did not differ from the breakpoint (P = 0.510). Maximal height, volume, and diameter of drusenoid PEDs were inversely correlated with final visual acuity (all P < 0.001) and positively correlated with the rate of PED collapse (all P < 0.001). Conclusions Spectral-domain OCT signatures, plausibly attributable to anteriorly migrated RPE and disintegration of the RPE layer, precede or occur simultaneously with changes in volume of drusenoid PED during the lifecycle of this lesion.
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Affiliation(s)
- Chandrakumar Balaratnasingam
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York, United States 2Vitreous-Retina-Macula Consultants of New York, New York, United States 3Department of Ophthalmology, New York University School of Medicine, New York, New York, United States 4Department of Physiology and Pharmacology, Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, Australia
| | - Lawrence A Yannuzzi
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York, United States 2Vitreous-Retina-Macula Consultants of New York, New York, United States
| | - Christine A Curcio
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, Alabama, United States
| | - William H Morgan
- Department of Ophthalmology, New York University School of Medicine, New York, New York, United States
| | - Giuseppe Querques
- Department of Ophthalmology, Hospital Intercommunal de Creteil, University Paris Est Creteil, Creteil, France 7Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, University Vita-Salute San Raffaele, Milan, Italy
| | - Vittorio Capuano
- Department of Ophthalmology, Hospital Intercommunal de Creteil, University Paris Est Creteil, Creteil, France
| | - Eric Souied
- Department of Ophthalmology, Hospital Intercommunal de Creteil, University Paris Est Creteil, Creteil, France 7Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, University Vita-Salute San Raffaele, Milan, Italy
| | - Jesse Jung
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York, United States 2Vitreous-Retina-Macula Consultants of New York, New York, United States 8East Bay Retina Consultants, Inc., Oakland, California, United States
| | - K Bailey Freund
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York, United States 2Vitreous-Retina-Macula Consultants of New York, New York, United States 3Department of Ophthalmology, New York University School of Medicine, New York, New York, United States
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Ilkan Z, Wright JR, Goodall AH, Gibbins JM, Jones CI, Mahaut-Smith MP. Evidence for shear-mediated Ca 2+ entry through mechanosensitive cation channels in human platelets and a megakaryocytic cell line. J Biol Chem 2017; 292:9204-9217. [PMID: 28416610 PMCID: PMC5454102 DOI: 10.1074/jbc.m116.766196] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 04/17/2017] [Indexed: 02/02/2023] Open
Abstract
The role of mechanosensitive (MS) Ca2+-permeable ion channels in platelets is unclear, despite the importance of shear stress in platelet function and life-threatening thrombus formation. We therefore sought to investigate the expression and functional relevance of MS channels in human platelets. The effect of shear stress on Ca2+ entry in human platelets and Meg-01 megakaryocytic cells loaded with Fluo-3 was examined by confocal microscopy. Cells were attached to glass coverslips within flow chambers that allowed applications of physiological and pathological shear stress. Arterial shear (1002.6 s-1) induced a sustained increase in [Ca2+] i in Meg-01 cells and enhanced the frequency of repetitive Ca2+ transients by 80% in platelets. These Ca2+ increases were abrogated by the MS channel inhibitor Grammostola spatulata mechanotoxin 4 (GsMTx-4) or by chelation of extracellular Ca2+ Thrombus formation was studied on collagen-coated surfaces using DiOC6-stained platelets. In addition, [Ca2+] i and functional responses of washed platelet suspensions were studied with Fura-2 and light transmission aggregometry, respectively. Thrombus size was reduced 50% by GsMTx-4, independently of P2X1 receptors. In contrast, GsMTx-4 had no effect on collagen-induced aggregation or on Ca2+ influx via TRPC6 or Orai1 channels and caused only a minor inhibition of P2X1-dependent Ca2+ entry. The Piezo1 agonist, Yoda1, potentiated shear-dependent platelet Ca2+ transients by 170%. Piezo1 mRNA transcripts and protein were detected with quantitative RT-PCR and Western blotting, respectively, in both platelets and Meg-01 cells. We conclude that platelets and Meg-01 cells express the MS cation channel Piezo1, which may contribute to Ca2+ entry and thrombus formation under arterial shear.
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Affiliation(s)
- Zeki Ilkan
- From the Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - Joy R Wright
- From the Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom.,the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research (NIHR) Cardiovascular Biomedical Research Unit, Glenfield Hospital, Leicester LE3 9QP, United Kingdom, and
| | - Alison H Goodall
- the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research (NIHR) Cardiovascular Biomedical Research Unit, Glenfield Hospital, Leicester LE3 9QP, United Kingdom, and
| | - Jonathan M Gibbins
- the School of Biological Sciences, University of Reading, Reading RG6 6AS, United Kingdom
| | - Chris I Jones
- the School of Biological Sciences, University of Reading, Reading RG6 6AS, United Kingdom
| | - Martyn P Mahaut-Smith
- From the Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom,
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Balaratnasingam C, Messinger JD, Sloan KR, Yannuzzi LA, Freund KB, Curcio CA. Histologic and Optical Coherence Tomographic Correlates in Drusenoid Pigment Epithelium Detachment in Age-Related Macular Degeneration. Ophthalmology 2017; 124:644-656. [PMID: 28153442 DOI: 10.1016/j.ophtha.2016.12.034] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 12/22/2016] [Accepted: 12/26/2016] [Indexed: 11/17/2022] Open
Abstract
PURPOSE Drusenoid pigment epithelium detachment (DPED) is a known precursor to geographic atrophy in age-related macular degeneration (AMD). We sought histologic correlates for spectral-domain (SD) optical coherence tomography (OCT) signatures in DPED and determined the frequency and origin of these OCT signatures in a clinical cohort of DPED eyes. DESIGN Laboratory imaging and histologic comparison, and retrospective, observational cohort study. PARTICIPANTS Four donor eyes with histopathologic diagnosis of AMD (2 with nonneovascular DPED and 2 with neovascular pigment epithelium detachment [PED]) and 49 eyes of 33 clinic patients with nonneovascular DPED more than 2 mm in diameter. METHODS Donor eyes underwent multimodal ex vivo imaging, including SD OCT, then processing for high-resolution histologic analysis. All clinic patients underwent SD OCT, near-infrared reflectance, and color photography. MAIN OUTCOME MEASURES Histologic correlates for SD OCT signatures in DPED, estimate of coverage by different retinal pigment epithelium (RPE) phenotypes in the DPED surface; frequency and origin of histologically verified SD OCT signatures in a clinical cohort of DPED eyes, and comparisons of histologic features between neovascular PED and DPED resulting from AMD. RESULTS Intraretinal and subretinal hyperreflective foci as seen on SD OCT correlated to RPE cells on histologic examination. Hypertransmission of light below the RPE-basal lamina band correlated with dissociated RPE. Subretinal hyperreflective material resulting from acquired vitelliform lesions corresponded to regions of apically expelled RPE organelles. In the clinical cohort, all histologically verified reflectivity signatures were visible and quantifiable. The appearance of intraretinal hyperreflective foci was preceded by thickening of the RPE-basal lamina band. Compared with PEDs associated with neovascular AMD, DPEDs had different crystallization patterns, no lipid-filled cells, and thinner basal laminar deposits. CONCLUSIONS Multiple RPE fates in AMD, including intraretinal cells that are highly prognostic for progression, can be followed and quantified reliably using eye-tracked serial SD OCT. This information may be particularly useful for obtaining an accurate timeline of incipient geographic atrophy in clinic populations and for quantifying anatomic end points and response to therapy in AMD clinical trials.
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Affiliation(s)
- Chandrakumar Balaratnasingam
- Vitreous Retina Macula Consultants of New York, New York, New York; LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Institute, New York, New York; Department of Ophthalmology, New York University Langone School of Medicine, New York, New York; Center for Ophthalmology and Visual Sciences, University of Western Australia, Perth, Australia
| | - Jeffrey D Messinger
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, Alabama
| | - Kenneth R Sloan
- Department of Computer and Information Sciences, University of Alabama at Birmingham, Birmingham, Alabama; Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, Alabama
| | - Lawrence A Yannuzzi
- Vitreous Retina Macula Consultants of New York, New York, New York; LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Institute, New York, New York
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, New York; LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Institute, New York, New York; Department of Ophthalmology, New York University Langone School of Medicine, New York, New York
| | - Christine A Curcio
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, Alabama.
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Circadian Kinetics of Cell Cycle Progression in Adult Neurogenic Niches of a Diurnal Vertebrate. J Neurosci 2017; 37:1900-1909. [PMID: 28087763 PMCID: PMC5320617 DOI: 10.1523/jneurosci.3222-16.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/08/2016] [Accepted: 01/05/2017] [Indexed: 01/03/2023] Open
Abstract
The circadian system may regulate adult neurogenesis via intracellular molecular clock mechanisms or by modifying the environment of neurogenic niches, with daily variation in growth factors or nutrients depending on the animal's diurnal or nocturnal lifestyle. In a diurnal vertebrate, zebrafish, we studied circadian distribution of immunohistochemical markers of the cell division cycle (CDC) in 5 of the 16 neurogenic niches of adult brain, the dorsal telencephalon, habenula, preoptic area, hypothalamus, and cerebellum. We find that common to all niches is the morning initiation of G1/S transition and daytime S-phase progression, overnight increase in G2/M, and cycle completion by late night. This is supported by the timing of gene expression for critical cell cycle regulators cyclins D, A2, and B2 and cyclin-dependent kinase inhibitor p20 in brain tissue. The early-night peak in p20, limiting G1/S transition, and its phase angle with the expression of core clock genes, Clock1 and Per1, are preserved in constant darkness, suggesting intrinsic circadian patterns of cell cycle progression. The statistical modeling of CDC kinetics reveals the significant circadian variation in cell proliferation rates across all of the examined niches, but interniche differences in the magnitude of circadian variation in CDC, S-phase length, phase angle of entrainment to light or clock, and its dispersion. We conclude that, in neurogenic niches of an adult diurnal vertebrate, the circadian modulation of cell cycle progression involves both systemic and niche-specific factors. SIGNIFICANCE STATEMENT This study establishes that in neurogenic niches of an adult diurnal vertebrate, the cell cycle progression displays a robust circadian pattern. Common to neurogenic niches located in diverse brain regions is daytime progression of DNA replication and nighttime mitosis, suggesting systemic regulation. Differences between neurogenic niches in the phase and degree of S-phase entrainment to the clock suggest additional roles for niche-specific regulatory mechanisms. Understanding the circadian regulation of adult neurogenesis can help optimize the timing of therapeutic approaches in patients with brain traumas or neurodegenerative disorders and preserve neural stem cells during cytostatic cancer therapies.
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Clinical Characteristics, Choroidal Neovascularization, and Predictors of Visual Outcomes in Acquired Vitelliform Lesions. Am J Ophthalmol 2016; 172:28-38. [PMID: 27640006 DOI: 10.1016/j.ajo.2016.09.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/07/2016] [Accepted: 09/07/2016] [Indexed: 01/29/2023]
Abstract
PURPOSE To quantify the temporal properties of the acquired vitelliform lesion (AVL) life cycle, define the clinical characteristics of choroidal neovascularization (NV) in this setting, and determine the predictors of long-term visual outcomes. DESIGN Retrospective cohort study. METHODS Clinical and imaging data from 199 eyes of 124 consecutive patients with AVLs associated with age-related macular degeneration (AMD) and adult-onset foveomacular vitelliform dystrophy (AOFVD) were analyzed. Volumetric calculations of vitelliform material were determined using spectral-domain optical coherence tomography and the temporal properties of the AVL life cycle were quantified. The clinical characteristics of NV were assessed, as were the predictors of final best-corrected visual acuity (BCVA) and change in BCVA. RESULTS Mean age was 79.2 ± 12.1 years. AVLs grew and collapsed at approximately the same rate (P = .275). Fifteen eyes (7.5%) developed NV, of which all were type 1. In 13 of these eyes, NV occurred during the collapse phase of the AVL life cycle, after the peak AVL volume was reached. The risk of NV (P = .006) and the decline in BCVA (P = .001) were both significantly greater among eyes with AMD. Foveal atrophy was the characteristic most significantly associated with final BCVA and change in BCVA from baseline (both P < .0005). The development of NV was not predictive of long-term visual outcomes (all P = .216). CONCLUSIONS Complications associated with AVLs typically occur during the collapse phase of the AVL life cycle. Visual outcomes and risk of NV are related to the underlying disease associated with AVLs.
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Design-Based Stereology for Evaluation of Histological Parameters. J Mol Neurosci 2016; 61:325-342. [PMID: 27826759 DOI: 10.1007/s12031-016-0858-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 10/21/2016] [Indexed: 12/21/2022]
Abstract
Valid quantification of organ volume and total cell numbers are crucial parameters for morphometric studies. The number of a specific cell type cannot be simply deduced from the number of its profiles found in thin tissue sections, as this parameter also depends on cell volume, tissue orientation as well as tissue atrophy. Design-based stereology has become the method of choice for unbiased, reproducible total cell number quantification. Steps described in this protocol include transcardial perfusion of mice, postfixation, and cryoprotection of the region of interest (ROI), followed by the preparation of a systematically and randomly sampled series of thick sections through the entire ROI. Furthermore, it is described how to perform immuno-histochemical staining of such thick cryo-sections, followed by providing a guidance for quantification of the ROI volume, the generation of unbiased virtual counting spaces, and steps to work with these counting spaces to obtain an unbiased estimate of total cell numbers.
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Oxidative insult can induce malaria-protective trait of sickle and fetal erythrocytes. Nat Commun 2016; 7:13401. [PMID: 27824335 PMCID: PMC5105170 DOI: 10.1038/ncomms13401] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 09/29/2016] [Indexed: 01/06/2023] Open
Abstract
Plasmodium falciparum infections can cause severe malaria, but not every infected person develops life-threatening complications. In particular, carriers of the structural haemoglobinopathies S and C and infants are protected from severe disease. Protection is associated with impaired parasite-induced host actin reorganization, required for vesicular trafficking of parasite-encoded adhesins, and reduced cytoadherence of parasitized erythrocytes in the microvasculature. Here we show that aberrant host actin remodelling and the ensuing reduced cytoadherence result from a redox imbalance inherent to haemoglobinopathic and fetal erythrocytes. We further show that a transient oxidative insult to wild-type erythrocytes before infection with P. falciparum induces the phenotypic features associated with the protective trait of haemoglobinopathic and fetal erythrocytes. Moreover, pretreatment of mice with the pro-oxidative nutritional supplement menadione mitigate the development of experimental cerebral malaria. Our results identify redox imbalance as a causative principle of protection from severe malaria, which might inspire host-directed intervention strategies.
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Balaratnasingam C, Inoue M, Ahn S, McCann J, Dhrami-Gavazi E, Yannuzzi LA, Freund KB. Visual Acuity Is Correlated with the Area of the Foveal Avascular Zone in Diabetic Retinopathy and Retinal Vein Occlusion. Ophthalmology 2016; 123:2352-2367. [PMID: 27523615 DOI: 10.1016/j.ophtha.2016.07.008] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/03/2016] [Accepted: 07/10/2016] [Indexed: 01/01/2023] Open
Abstract
PURPOSE To determine if the area of the foveal avascular zone (FAZ) is correlated with visual acuity (VA) in diabetic retinopathy (DR) and retinal vein occlusion (RVO). DESIGN Cross-sectional study. PARTICIPANTS Ninety-five eyes of 66 subjects with DR (65 eyes), branch retinal vein occlusion (19 eyes), and central retinal vein occlusion (11 eyes). METHODS Structural optical coherence tomography (OCT; Spectralis, Heidelberg Engineering) and OCT angiography (OCTA; Avanti, Optovue RTVue XR) data from a single visit were analyzed. FAZ area, point thickness of central fovea, central 1-mm subfield thickness, the occurrence of intraretinal cysts, ellipsoid zone disruption, and disorganization of retinal inner layers (DRIL) length were measured. VA was also recorded. Correlations between FAZ area and VA were explored using regression models. Main outcome measure was VA. RESULTS Mean age was 62.9±13.2 years. There was no difference in demographic and OCT-derived anatomic measurements between branch retinal vein occlusion and central retinal vein occlusion groups (all P ≥ 0.058); therefore, data from the 2 groups were pooled together to a single RVO group for further statistical comparisons. Univariate and multiple regression analysis showed that the area of the FAZ was significantly correlated with VA in DR and RVO (all P ≤ 0.003). The relationship between FAZ area and VA varied with age (P = 0.026) such that for a constant FAZ area, an increase in patient age was associated with poorer vision (rise in logarithm of the minimum angle of resolution visual acuity). Disruption of the ellipsoid zone was significantly correlated with VA in univariate and multiple regression analysis (both P < 0.001). Occurrence of intraretinal cysts, DRIL length, and lens status were significantly correlated with VA in the univariate regression analysis (P ≤ 0.018) but not the multiple regression analysis (P ≥ 0.210). Remaining variables evaluated in this study were not predictive of VA (all P ≥ 0.225). CONCLUSIONS The area of the FAZ is significantly correlated with VA in DR and RVO and this relationship is modulated by patient age. Further study about FAZ area and VA correlations during the natural course of retinal vascular diseases and following treatment is warranted.
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Affiliation(s)
- Chandrakumar Balaratnasingam
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York; Vitreous Retina Macula Consultants of New York, New York, New York; Department of Ophthalmology, New York University School of Medicine, New York, New York; Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, Australia.
| | - Maiko Inoue
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York; Vitreous Retina Macula Consultants of New York, New York, New York
| | - Seungjun Ahn
- Department of Biostatistics, Columbia University Medical Center, New York, New York
| | - Jesse McCann
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York; Vitreous Retina Macula Consultants of New York, New York, New York; Department of Ophthalmology, New York University School of Medicine, New York, New York
| | - Elona Dhrami-Gavazi
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York; Vitreous Retina Macula Consultants of New York, New York, New York; Department of Ophthalmology, New York University School of Medicine, New York, New York
| | - Lawrence A Yannuzzi
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York; Vitreous Retina Macula Consultants of New York, New York, New York
| | - K Bailey Freund
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, New York; Vitreous Retina Macula Consultants of New York, New York, New York; Department of Ophthalmology, New York University School of Medicine, New York, New York
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Alvarez-Argote S, Gransee HM, Mora JC, Stowe JM, Jorgenson AJ, Sieck GC, Mantilla CB. The Impact of Midcervical Contusion Injury on Diaphragm Muscle Function. J Neurotrauma 2015; 33:500-9. [PMID: 26413840 DOI: 10.1089/neu.2015.4054] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Midcervical contusion injuries disrupt descending ipsilateral excitatory bulbospinal projections to phrenic motoneurons, compromising ventilation. We hypothesized that a unilateral contusion injury at C3 versus C5 would differentially impact phrenic activity reflecting more prominent disruption of ipsilateral descending excitatory drive to more caudal segments of the phrenic motor pool with more cranial injuries. Phrenic motoneuron counts and evidence of diaphragm muscle denervation at individual neuromuscular junctions (NMJ) were evaluated at 14 days post-injury after unilateral contusion injury (100 kDynes). Whole body plethysmography and chronic diaphragm EMG were measured before the injury and at 3, 7, and 14 days post-injury. Contusion injuries at either level resulted in a similarly sized cavity. C3 contusion resulted in loss of 39 ± 13% of ipsilateral phrenic motoneurons compared with 13 ± 21% after C5 contusion (p = 0.003). Cervical contusion injuries resulted in diaphragm muscle denervation (C3 contusion: 17 ± 4%; C5 contusion: 7 ± 4%; p = 0.047). The pattern of denervation revealed segmental innervation of the diaphragm muscle, with greater denervation ventrally after C3 contusion and dorsally after C5 contusion. Overall, diaphragm root mean square electromyography activity did not change ipsilaterally after C3 or C5 contusion, but increased contralaterally (∼ 11%) after C3 contusion only on the first day post-injury (p = 0.026). Similarly, there were no significant changes in breathing parameters during eupnea or exposure to hypoxia (10% O2) - hypercapnia (5% CO2) at any time post-injury. Unilateral midcervical contusions minimally impair ventilatory behaviors despite phrenic motoneuron loss and diaphragm muscle denervation.
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Affiliation(s)
| | - Heather M Gransee
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Juan C Mora
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Jessica M Stowe
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Amy J Jorgenson
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Gary C Sieck
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,2 Department of Anesthesiology, Mayo Clinic , Rochester, Minnesota
| | - Carlos B Mantilla
- 1 Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,2 Department of Anesthesiology, Mayo Clinic , Rochester, Minnesota
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Greising SM, Stowe JM, Sieck GC, Mantilla CB. Role of TrkB kinase activity in aging diaphragm neuromuscular junctions. Exp Gerontol 2015; 72:184-91. [PMID: 26517952 DOI: 10.1016/j.exger.2015.10.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/23/2015] [Accepted: 10/26/2015] [Indexed: 11/30/2022]
Abstract
Brain derived neurotrophic factor (BDNF) acting through the tropomyosin-related kinase receptor B (TrkB) enhances neuromuscular transmission in the diaphragm muscle of adult mice, reflecting presynaptic effects. With aging, BDNF enhancement of neuromuscular transmission is lost. We hypothesize that disrupting BDNF/TrkB signaling in early old age will reveal a period of susceptibility evident by morphological changes at neuromuscular junctions (NMJ). Adult, male TrkB(F616A) mice (n=25) at 6 and 18 months of age, were used to examine the structural properties of diaphragm muscle NMJs (n=1097). Confocal microscopy was used to compare pre- and post-synaptic morphology and denervation following a 7 day treatment with the phosphoprotein phosphatase-1 derivative 1NMPP1, which inhibits TrkB kinase activity in TrkB(F616A) mice vs. vehicle treatment. In early old age (18 months), presynaptic terminal volume decreased compared to 6 month old diaphragm NMJs (~20%). Inhibition of TrkB kinase activity significantly decreased the presynaptic terminal volume (~20%) and motor end-plate 2D planar area (~10%), independent of age group. Inhibition of TrkB kinase activity in early old age significantly reduced overlap of pre- and post-synaptic structures and increased the proportion of denervated NMJs (to ~20%). Collectively these results support a period of susceptibility in early old age when BDNF/TrkB signaling at diaphragm NMJs supports the maintenance of NMJs structure and muscle innervation.
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Affiliation(s)
- Sarah M Greising
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Jessica M Stowe
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; Department of Anesthesiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; Department of Anesthesiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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Bonzano S, Bovetti S, Fasolo A, Peretto P, De Marchis S. Odour enrichment increases adult-born dopaminergic neurons in the mouse olfactory bulb. Eur J Neurosci 2014; 40:3450-7. [DOI: 10.1111/ejn.12724] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 08/13/2014] [Accepted: 08/15/2014] [Indexed: 10/24/2022]
Affiliation(s)
- Sara Bonzano
- Department of Life Sciences and Systems Biology; University of Torino; Via Accademia Albertina 13 10123 Torino Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO); Orbassano Italy
| | - Serena Bovetti
- Department of Life Sciences and Systems Biology; University of Torino; Via Accademia Albertina 13 10123 Torino Italy
| | - Aldo Fasolo
- Department of Life Sciences and Systems Biology; University of Torino; Via Accademia Albertina 13 10123 Torino Italy
| | - Paolo Peretto
- Department of Life Sciences and Systems Biology; University of Torino; Via Accademia Albertina 13 10123 Torino Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO); Orbassano Italy
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology; University of Torino; Via Accademia Albertina 13 10123 Torino Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO); Orbassano Italy
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Mantilla CB, Stowe JM, Sieck DC, Ermilov LG, Greising SM, Zhang C, Shokat KM, Sieck GC. TrkB kinase activity maintains synaptic function and structural integrity at adult neuromuscular junctions. J Appl Physiol (1985) 2014; 117:910-20. [PMID: 25170066 DOI: 10.1152/japplphysiol.01386.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Activation of the tropomyosin-related kinase receptor B (TrkB) by brain-derived neurotrophic factor acutely regulates synaptic transmission at adult neuromuscular junctions (NMJs). The role of TrkB kinase activity in the maintenance of NMJ function and structure at diaphragm muscle NMJs was explored using a chemical-genetic approach that permits reversible inactivation of TrkB kinase activity in TrkB(F616A) mice by 1NMPP1. Inhibiting TrkB kinase activity for 7 days resulted in significant, yet reversible, impairments in neuromuscular transmission at diaphragm NMJs. Neuromuscular transmission failure following 2 min of repetitive phrenic nerve stimulation increased from 42% in control to 59% in 1NMPP1-treated TrkB(F616A) mice (P = 0.010). Recovery of TrkB kinase activity following withdrawal of 1NMPP1 treatment improved neuromuscular transmission (P = 0.006). Electrophysiological measurements at individual diaphragm NMJs documented lack of differences in quantal content in control and 1NMPP1-treated mice (P = 0.845). Morphological changes at diaphragm NMJs were modest following inhibition and recovery of TrkB kinase activity. Three-dimensional reconstructions of diaphragm NMJs revealed no differences in volume at motor end plates (labeled by α-bungarotoxin; P = 0.982) or presynaptic terminals (labeled by synaptophysin; P = 0.515). Inhibition of TrkB kinase activity by 1NMPP1 resulted in more compact NMJs, with increased apposition of presynaptic terminals and motor end plates (P = 0.017) and reduced fragmentation of motor end plates (P = 0.005). Recovery of TrkB kinase activity following withdrawal of 1NMPP1 treatment resulted in postsynaptic remodeling likely reflecting increased gutter depth (P = 0.007), without significant presynaptic changes. These results support an essential role for TrkB kinase activity in maintaining synaptic function and structural integrity at NMJs in the adult mouse diaphragm muscle.
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Affiliation(s)
- Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota; Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota; and
| | - Jessica M Stowe
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Dylan C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Leonid G Ermilov
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Sarah M Greising
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Chao Zhang
- Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, California
| | - Kevan M Shokat
- Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, California
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota; Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota; and
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Bovetti S, Bonzano S, Garzotto D, Giannelli SG, Iannielli A, Armentano M, Studer M, De Marchis S. COUP-TFI controls activity-dependent tyrosine hydroxylase expression in adult dopaminergic olfactory bulb interneurons. Development 2013; 140:4850-9. [DOI: 10.1242/dev.089961] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
COUP-TFI is an orphan nuclear receptor acting as a strong transcriptional regulator in different aspects of forebrain embryonic development. In this study, we investigated COUP-TFI expression and function in the mouse olfactory bulb (OB), a highly plastic telencephalic region in which continuous integration of newly generated inhibitory interneurons occurs throughout life. OB interneurons belong to different populations that originate from distinct progenitor lineages. Here, we show that COUP-TFI is highly expressed in tyrosine hydroxylase (TH)-positive dopaminergic interneurons in the adult OB glomerular layer (GL). We found that odour deprivation, which is known to downregulate TH expression in the OB, also downregulates COUP-TFI in dopaminergic cells, indicating a possible correlation between TH- and COUP-TFI-activity-dependent action. Moreover, we demonstrate that conditional inactivation of COUP-TFI in the EMX1 lineage results in a significant reduction of both TH and ZIF268 expression in the GL. Finally, lentiviral vector-mediated COUP-TFI deletion in adult-generated interneurons confirmed that COUP-TFI acts cell-autonomously in the control of TH and ZIF268 expression. These data indicate that COUP-TFI regulates TH expression in OB cells through an activity-dependent mechanism involving ZIF268 induction and strongly argue for a maintenance rather than establishment function of COUP-TFI in dopaminergic commitment. Our study reveals a previously unknown role for COUP-TFI in the adult brain as a key regulator in the control of sensory-dependent plasticity in olfactory dopaminergic neurons.
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Affiliation(s)
- Serena Bovetti
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Torino, Italy
| | - Sara Bonzano
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Torino, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gerzole 10, 10043, Orbassano, Italy
| | - Donatella Garzotto
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Torino, Italy
| | - Serena Gea Giannelli
- San Raffaele Telethon Institute for Gene Therapy (HSR-TIGET), Division of Regenerative Medicine, Stem Cells, and Gene Therapy, San Raffaele Scientific Institute, Via Olgettina28, 20132, Milano, Italy
| | - Angelo Iannielli
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Torino, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gerzole 10, 10043, Orbassano, Italy
| | - Maria Armentano
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gerzole 10, 10043, Orbassano, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Via P. Castellino 111, 80131, Napoli, Italy
| | - Michèle Studer
- Telethon Institute of Genetics and Medicine (TIGEM), Via P. Castellino 111, 80131, Napoli, Italy
- University of Nice Sophia-Antipolis, Parc Valrose, 28 Avenue Valrose, F-06108 Nice, France
- INSERM UMR 1091, Parc Valrose, 28 Avenue Valrose, F-06108 Nice, France
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Torino, Italy
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Regione Gerzole 10, 10043, Orbassano, Italy
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Mantilla CB, Gransee HM, Zhan WZ, Sieck GC. Motoneuron BDNF/TrkB signaling enhances functional recovery after cervical spinal cord injury. Exp Neurol 2013; 247:101-9. [PMID: 23583688 DOI: 10.1016/j.expneurol.2013.04.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/02/2013] [Accepted: 04/03/2013] [Indexed: 01/09/2023]
Abstract
A C2 cervical spinal cord hemisection (SH) interrupts descending inspiratory-related drive to phrenic motoneurons located between C3 and C5 in rats, paralyzing the ipsilateral hemidiaphragm muscle. There is gradual recovery of rhythmic diaphragm muscle activity ipsilateral to cervical spinal cord injury over time, consistent with neuroplasticity and strengthening of spared, contralateral descending premotor input to phrenic motoneurons. Brain-derived neurotrophic factor (BDNF) signaling through the tropomyosin related kinase receptor subtype B (TrkB) plays an important role in neuroplasticity following spinal cord injury. We hypothesized that 1) increasing BDNF/TrkB signaling at the level of the phrenic motoneuron pool by intrathecal BDNF delivery enhances functional recovery of rhythmic diaphragm activity after SH, and 2) inhibiting BDNF/TrkB signaling by quenching endogenous neurotrophins with the soluble fusion protein TrkB-Fc or by knocking down TrkB receptor expression in phrenic motoneurons using intrapleurally-delivered siRNA impairs functional recovery after SH. Diaphragm EMG electrodes were implanted bilaterally to verify complete hemisection at the time of SH and 3days post-SH. After SH surgery in adult rats, an intrathecal catheter was placed at C4 to chronically infuse BDNF or TrkB-Fc using an implanted mini-osmotic pump. At 14days post-SH, all intrathecal BDNF treated rats (n=9) displayed recovery of ipsilateral hemidiaphragm EMG activity, compared to 3 out of 8 untreated SH rats (p<0.01). During eupnea, BDNF treated rats exhibited 76±17% of pre-SH root mean squared EMG vs. only 5±3% in untreated SH rats (p<0.01). In contrast, quenching endogenous BDNF with intrathecal TrkB-Fc treatment completely prevented functional recovery up to 14days post-SH (n=7). Immunoreactivity of the transcription factor cAMP response element-binding protein (CREB), a downstream effector of TrkB signaling, increased in phrenic motoneurons following BDNF treatment (n=6) compared to artificial cerebrospinal fluid treatment (n=6; p<0.001). Intrapleural injections of non-sense or TrkB siRNA were administered after SH to specifically target phrenic motoneurons. At 14days post-SH, none out of 9 TrkB siRNA treated rats displayed functional recovery compared to 5 out of 9 non-sense siRNA treated rats. These results indicate that BDNF/TrkB signaling in phrenic motoneuron pool plays a critical role in functional recovery after cervical spinal cord injury.
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Affiliation(s)
- Carlos B Mantilla
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
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Pugh N, Jarvis GE, Koch A, Sakariassen KS, Davis B, Farndale RW. The impact of factor Xa inhibition on axial dependent arterial thrombus formation triggered by a tissue factor rich surface. J Thromb Thrombolysis 2011; 33:6-15. [PMID: 22120925 DOI: 10.1007/s11239-011-0658-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This study was designed to assess the effect of Factor Xa antagonists on thrombus formation at various axial positions on a tissue factor rich surface under arterial blood flow conditions. Non-anticoagulated, flowing human blood, drawn directly from an antecubital vein, was perfused over a tissue factor coated cover slip in a parallel-plate perfusion chamber. Thrombus surface coverage, thrombus mean height and fibrin surface coverage were measured at six different axial positions by confocal microscopy. Both thrombus surface coverage and mean height decreased along the cover slip axis whereas the fibrin surface coverage increased. Pre-chamber treatment of blood with the direct Factor Xa inhibitors Razaxaban and 813893 resulted in significantly reduced thrombus and fibrin formation at all axial positions investigated (P < 0.05). Thrombus and fibrin deposition in a laminar flow chamber changed with axial position with surface coverage measurements being more reproducible than thrombus mean height. Data were more reproducible towards the centre of the flow chamber than at the extremities. Razaxaban and 813893 inhibited thrombus and fibrin formation at the highest concentrations tested. No difference in drug effect was apparent at different axial positions. In conclusion, axial position influences the degree of thrombus and fibrin deposition with measurements being less reproducible at the extremities of the flow chamber. This technique may prove useful for analysing anti-thrombotic drug effects before progression to clinical trials.
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Affiliation(s)
- Nicholas Pugh
- Department of Biochemistry, University of Cambridge, Cambridge CB1 2QW, UK.
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Sieck DC, Zhan WZ, Fang YH, Ermilov LG, Sieck GC, Mantilla CB. Structure-activity relationships in rodent diaphragm muscle fibers vs. neuromuscular junctions. Respir Physiol Neurobiol 2011; 180:88-96. [PMID: 22063925 DOI: 10.1016/j.resp.2011.10.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 10/20/2011] [Accepted: 10/21/2011] [Indexed: 12/01/2022]
Abstract
The diaphragm muscle (DIAm) is a highly active muscle of mixed fiber type composition. We hypothesized that consistent with greater activation history and proportion of fatigue-resistant fibers, neuromuscular transmission failure is lower in the mouse compared to the rat DIAm, and that neuromuscular junction (NMJ) morphology will match their different functional demands. Minute ventilation and duty cycle were higher in the mouse than in the rat. The proportion of fatigue-resistant fibers was similar in the rat and mouse; however the contribution of fatigue-resistant fibers to total DIAm mass was higher in the mouse. Neuromuscular transmission failure was less in mice than in rats. Motor end-plate area differed across fibers in rat but not in mouse DIAm, where NMJs displayed greater complexity overall. Thus, differences across species in activation history and susceptibility to neuromuscular transmission failure are reflected in the relative contribution of fatigue resistant muscle fibers to total DIAm mass, but not in type-dependent morphological differences at the NMJ.
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Affiliation(s)
- Dylan C Sieck
- Department of Anesthesiology, College of Medicine, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
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Abstract
The neuregulin (NRG) family of trophic factors is present in the central and peripheral nervous systems and participates in the survival, proliferation, and differentiation of many different cell types, including motoneurons. NRG1 was first characterized by its role in the formation of the neuromuscular junction, and recently it was shown to play a crucial role in modulating glutamatergic and cholinergic transmission in the central nervous system of adult rats. However, little is known about NRG1's role in adult motor systems. Motoneurons receive dense glutamatergic and cholinergic input. We hypothesized that NRG1 is present at synapses on phrenic motoneurons. Confocal microscopy and 3D reconstruction techniques were used to determine the distribution of NRG1 and its colocalization with these different neurotransmitter systems. We found that NRG1 puncta are present around retrogradely labeled motoneurons and are distributed predominantly at motoneuron somata and primary dendrites. NRG1 is present exclusively at synaptic sites (identified using the presynaptic marker synaptophysin), making up ∼30% of all synapses at phrenic motoneurons. Overall, NRG1 immunoreactivity is found predominantly at cholinergic synapses (75% ± 14% colocalize with the vesicular acetylcholine transporter; VAChT). Nearly all (99% ± 1%) VAChT-immunoreactive synapses expressed NRG1. NRG1 also is present at a subset of glutamatergic synapses expressing the vesicular glutamate transporter (VGLUT) type 2 (∼6%) but not those expressing VGLUT type 1. Overall, 26% ± 6% of NRG1 synapses are VGLUT2 immunoreactive. These findings provide the first evidence suggesting that NRG1 may modulate synaptic activity in adult motor systems.
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Affiliation(s)
- Amine N Issa
- Department of Physiology and Biomedical Engineering, College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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