1
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Corridon PR. Enhancing the expression of a key mitochondrial enzyme at the inception of ischemia-reperfusion injury can boost recovery and halt the progression of acute kidney injury. Front Physiol 2023; 14:1024238. [PMID: 36846323 PMCID: PMC9945300 DOI: 10.3389/fphys.2023.1024238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
Hydrodynamic fluid delivery has shown promise in influencing renal function in disease models. This technique provided pre-conditioned protection in acute injury models by upregulating the mitochondrial adaptation, while hydrodynamic injections of saline alone have improved microvascular perfusion. Accordingly, hydrodynamic mitochondrial gene delivery was applied to investigate the ability to halt progressive or persistent renal function impairment following episodes of ischemia-reperfusion injuries known to induce acute kidney injury (AKI). The rate of transgene expression was approximately 33% and 30% in rats with prerenal AKI that received treatments 1 (T1hr) and 24 (T24hr) hours after the injury was established, respectively. The resulting mitochondrial adaptation via exogenous IDH2 (isocitrate dehydrogenase 2 (NADP+) and mitochondrial) significantly blunted the effects of injury within 24 h of administration: decreased serum creatinine (≈60%, p < 0.05 at T1hr; ≈50%, p < 0.05 at T24hr) and blood urea nitrogen (≈50%, p < 0.05 at T1hr; ≈35%, p < 0.05 at T24hr) levels, and increased urine output (≈40%, p < 0.05 at T1hr; ≈26%, p < 0.05 at T24hr) and mitochondrial membrane potential, Δψm, (≈ by a factor of 13, p < 0.001 at T1hr; ≈ by a factor of 11, p < 0.001 at T24hr), despite elevated histology injury score (26%, p < 0.05 at T1hr; 47%, p < 0.05 at T24hr). Therefore, this study identifies an approach that can boost recovery and halt the progression of AKI at its inception.
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Affiliation(s)
- Peter R. Corridon
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates,Healthcare Engineering Innovation Center, Khalifa University, Abu Dhabi, United Arab Emirates,Center for Biotechnology, Khalifa University, Abu Dhabi, United Arab Emirates,*Correspondence: Peter R. Corridon,
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2
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Sun XS, Wang XL, Bai M, Song C, Eaton DC, Yue Q, Martin KK, Cai H, Garraway S, Wang LH, Ma HP. Atrial Natriuretic Peptide and the Epithelial Sodium Channel Contribute to Spinal Cord Injury-Induced Polyuria in Mice. J Neurotrauma 2022; 39:724-734. [PMID: 35216518 PMCID: PMC9081061 DOI: 10.1089/neu.2021.0305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Polyuria is found in patients with spinal cord injury (SCI). However, the underlying cellular and molecular mechanism is unknown. Here, we show that mice had elevated urine for 7 days after T10 contusion. Using multi-photon confocal microscopy, we performed intra-vital imaging experiments to evaluate water reabsorption in kidney tubules by examining fluorescent intensity in the lumen of the distal tubule from live mice. The data show that SCI significantly reduced the concentrating function of kidney tubules. The reduced water reabsorption appears to be mediated by atrial natriuretic peptide (ANP) because SCI increased the expression levels of both ANP and natriuretic peptide receptor A (NPR-A) in the kidney cortex. Our patch-clamp single-channel recordings from split-open distal tubules show that SCI decreased the activity of the epithelial sodium channel (ENaC). Western blot combined with confocal microscopy data show that the levels of 70 kD γ-ENaC, which is an active isoform because of proteolytic cleavage, were significantly reduced in distal tubule principal cells. An NPR-A inhibitor (A71915) given intravenously eliminated the effects of SCI on ENaC and polyuria. These data together with previous studies suggest that SCI causes polyuria, probably by reducing ENaC activity through elevating ANP and NPR-A. Further investigation of the signal transduction pathways may provide useful information for discovering an efficient drug to treat SCI-induced polyuria.
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Affiliation(s)
- Xue-Song Sun
- Department of Neurology, the Second Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China.,Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Xiao-Long Wang
- Department of Orthopedic Surgery, Cancer Hospital of Harbin Medical University, Harbin, People's Republic of China
| | - Ming Bai
- Department of Neurology, the Second Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China
| | - Chang Song
- Department of Neurology, the Second Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China.,Renal Division, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Douglas C. Eaton
- Renal Division, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Qiang Yue
- Renal Division, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Karmarcha K. Martin
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Hui Cai
- Renal Division, Emory University School of Medicine, Atlanta, Georgia, USA.,Section of Nephrology, Atlanta VA Medical Center, Decatur, Georgia, USA
| | - Sandra Garraway
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Li-Hua Wang
- Department of Neurology, the Second Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China.,Address correspondence to: Li-Hua Wang, MD, Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China
| | - He-Ping Ma
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA.,He-Ping Ma, MD, Department of Cell Biology, Emory University School of Medicine, 615 Michael ST, Suite 601, Atlanta, GA 30322, USA
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3
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Abstract
Fluorescence microscopy has represented a crucial technique to explore the cellular and molecular mechanisms in the field of biomedicine. However, the conventional one-photon microscopy exhibits many limitations when living samples are imaged. The new technologies, including two-photon microscopy (2PM), have considerably improved the in vivo study of pathophysiological processes, allowing the investigators to overcome the limits displayed by previous techniques. 2PM enables the real-time intravital imaging of the biological functions in different organs at cellular and subcellular resolution thanks to its improved laser penetration and less phototoxicity. The development of more sensitive detectors and long-wavelength fluorescent dyes as well as the implementation of semi-automatic software for data analysis allowed to gain insights in essential physiological functions, expanding the frontiers of cellular and molecular imaging. The future applications of 2PM are promising to push the intravital microscopy beyond the existing limits. In this review, we provide an overview of the current state-of-the-art methods of intravital microscopy, focusing on the most recent applications of 2PM in kidney physiology.
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4
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Costanzo V, D’Apolito L, Sardella D, Iervolino A, La Manna G, Capasso G, Frische S, Trepiccione F. Single nephron glomerular filtration rate measured by linescan multiphoton microscopy compared to conventional micropuncture. Pflugers Arch 2022; 474:733-741. [PMID: 35397662 PMCID: PMC9192459 DOI: 10.1007/s00424-022-02686-8] [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] [Received: 12/02/2021] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 12/19/2022]
Abstract
Renal micropuncture, which requires the direct access to the renal tubules, has for long time been the technique of choice to measure the single nephron glomerular filtration rate (SNGFR) in animal models. This approach is challenging by virtue of complex animal preparation and numerous technically difficult steps. The introduction of intravital multiphoton microscopy (MPM) offers another approach to the measure of the SNGFR by mean of the high laser-tissue penetration and the optical sectioning capacity. Previous MPM studies measuring SNGFR in vivo relied on fast full-frame acquisition during the filtration process obtainable with high performance resonant scanners. In this study, we describe an innovative linescan–based MPM method. The new method can discriminate SNGFR variations both in conditions of low and high glomerular filtration, and shows results comparable to conventional micropuncture both for rats and mice. Moreover, this novel approach has improved spatial and time resolution and is faster than previous methods, thus enabling the investigation of SNGFR from more tubules and improving options for data-analysis.
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5
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Molitoris BA, Sandoval RM, Yadav SPS, Wagner MC. Albumin Uptake and Processing by the Proximal Tubule: Physiologic, Pathologic and Therapeutic Implications. Physiol Rev 2022; 102:1625-1667. [PMID: 35378997 PMCID: PMC9255719 DOI: 10.1152/physrev.00014.2021] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
For nearly 50 years the proximal tubule (PT) has been known to reabsorb, process, and either catabolize or transcytose albumin from the glomerular filtrate. Innovative techniques and approaches have provided insights into these processes. Several genetic diseases, nonselective PT cell defects, chronic kidney disease (CKD), and acute PT injury lead to significant albuminuria, reaching nephrotic range. Albumin is also known to stimulate PT injury cascades. Thus, the mechanisms of albumin reabsorption, catabolism, and transcytosis are being reexamined with the use of techniques that allow for novel molecular and cellular discoveries. Megalin, a scavenger receptor, cubilin, amnionless, and Dab2 form a nonselective multireceptor complex that mediates albumin binding and uptake and directs proteins for lysosomal degradation after endocytosis. Albumin transcytosis is mediated by a pH-dependent binding affinity to the neonatal Fc receptor (FcRn) in the endosomal compartments. This reclamation pathway rescues albumin from urinary losses and cellular catabolism, extending its serum half-life. Albumin that has been altered by oxidation, glycation, or carbamylation or because of other bound ligands that do not bind to FcRn traffics to the lysosome. This molecular sorting mechanism reclaims physiological albumin and eliminates potentially toxic albumin. The clinical importance of PT albumin metabolism has also increased as albumin is now being used to bind therapeutic agents to extend their half-life and minimize filtration and kidney injury. The purpose of this review is to update and integrate evolving information regarding the reabsorption and processing of albumin by proximal tubule cells including discussion of genetic disorders and therapeutic considerations.
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Affiliation(s)
- Bruce A. Molitoris
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
- Dept.of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Ruben M. Sandoval
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Shiv Pratap S. Yadav
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Mark C. Wagner
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
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6
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Intravital imaging of real-time endogenous actin dysregulation in proximal and distal tubules at the onset of severe ischemia-reperfusion injury. Sci Rep 2021; 11:8280. [PMID: 33859322 PMCID: PMC8050301 DOI: 10.1038/s41598-021-87807-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/05/2021] [Indexed: 11/15/2022] Open
Abstract
Severe renal ischemia-reperfusion injury (IRI) can lead to acute and chronic kidney dysfunction. Cytoskeletal modifications are among the main effects of this condition. The majority of studies that have contributed to the current understanding of IRI have relied on histological analyses using exogenous probes after the fact. Here we report the successful real-time visualization of actin cytoskeletal alterations in live proximal and distal tubules that arise at the onset of severe IRI. To achieve this, we induced fluorescent actin expression in these segments in rats with hydrodynamic gene delivery (HGD). Using intravital two-photon microscopy we then tracked and quantified endogenous actin dysregulation that occurred by subjecting these animals to 60 min of bilateral renal ischemia. Rapid (by 1-h post-reperfusion) and significant (up to 50%) declines in actin content were observed. The decline in fluorescence within proximal tubules was significantly greater than that observed in distal tubules. Actin-based fluorescence was not recovered during the measurement period extending 24 h post-reperfusion. Such injury decimated the renal architecture, in particular, actin brush borders, and hampered the reabsorptive and filtrative capacities of these tubular compartments. Thus, for the first time, we show that the combination of HGD and intravital microscopy can serve as an experimental tool to better understand how IRI modifies the cytoskeleton in vivo and provide an extension to current histopathological techniques.
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7
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Ranjit S, Lanzanò L, Libby AE, Gratton E, Levi M. Advances in fluorescence microscopy techniques to study kidney function. Nat Rev Nephrol 2020; 17:128-144. [PMID: 32948857 DOI: 10.1038/s41581-020-00337-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2020] [Indexed: 02/07/2023]
Abstract
Fluorescence microscopy, in particular immunofluorescence microscopy, has been used extensively for the assessment of kidney function and pathology for both research and diagnostic purposes. The development of confocal microscopy in the 1950s enabled imaging of live cells and intravital imaging of the kidney; however, confocal microscopy is limited by its maximal spatial resolution and depth. More recent advances in fluorescence microscopy techniques have enabled increasingly detailed assessment of kidney structure and provided extraordinary insights into kidney function. For example, nanoscale precise imaging by rapid beam oscillation (nSPIRO) is a super-resolution microscopy technique that was originally developed for functional imaging of kidney microvilli and enables detection of dynamic physiological events in the kidney. A variety of techniques such as fluorescence recovery after photobleaching (FRAP), fluorescence correlation spectroscopy (FCS) and Förster resonance energy transfer (FRET) enable assessment of interaction between proteins. The emergence of other super-resolution techniques, including super-resolution stimulated emission depletion (STED), photoactivated localization microscopy (PALM), stochastic optical reconstruction microscopy (STORM) and structured illumination microscopy (SIM), has enabled functional imaging of cellular and subcellular organelles at ≤50 nm resolution. The deep imaging via emission recovery (DIVER) detector allows deep, label-free and high-sensitivity imaging of second harmonics, enabling assessment of processes such as fibrosis, whereas fluorescence lifetime imaging microscopy (FLIM) enables assessment of metabolic processes.
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Affiliation(s)
- Suman Ranjit
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC, USA. .,Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA, USA.
| | - Luca Lanzanò
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy.,Department of Physics and Astronomy "Ettore Majorana", University of Catania, Catania, Italy
| | - Andrew E Libby
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC, USA
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA, USA.
| | - Moshe Levi
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC, USA.
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8
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Bordoni L, Sardella D, Schiessl IM. A Porthole over AKI: Cell Dynamics in Damage and Repair. Nephron Clin Pract 2020; 144:650-654. [PMID: 32604088 DOI: 10.1159/000508504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/07/2020] [Indexed: 11/19/2022] Open
Abstract
Acute kidney injury (AKI) is associated with an increased risk of CKD. Injury-induced multifaceted renal cell-to-cell crosstalk can either lead to successful self-repair or chronic fibrosis and inflammation. In this mini-review, we will discuss critical renal cell types acting as victims or executioners in AKI pathology and introduce intravital imaging as a powerful technique to further dissect these cell-to-cell interactions.
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Affiliation(s)
- Luca Bordoni
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Donato Sardella
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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9
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De Niz M, Carvalho T, Penha-Gonçalves C, Agop-Nersesian C. Intravital imaging of host-parasite interactions in organs of the thoracic and abdominopelvic cavities. Cell Microbiol 2020; 22:e13201. [PMID: 32149435 DOI: 10.1111/cmi.13201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/03/2020] [Accepted: 03/06/2020] [Indexed: 12/16/2022]
Abstract
Infections with protozoan and helminthic parasites affect multiple organs in the mammalian host. Imaging pathogens in their natural environment takes a more holistic view on biomedical aspects of parasitic infections. Here, we focus on selected organs of the thoracic and abdominopelvic cavities most commonly affected by parasites. Parasitic infections of these organs are often associated with severe medical complications or have health implications beyond the infected individual. Intravital imaging has provided a more dynamic picture of the host-parasite interplay and contributed not only to our understanding of the various disease pathologies, but has also provided fundamental insight into the biology of the parasites.
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Affiliation(s)
- Mariana De Niz
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Instituto de Medicina Molecular - João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Tânia Carvalho
- Instituto de Medicina Molecular - João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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10
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Miyazaki T, Gharib SA, Hsu YWA, Xu K, Khodakivskyi P, Kobayashi A, Paragas J, Klose AD, Francis KP, Dubikovskaya E, Page-McCaw PS, Barasch J, Paragas N. Cell-specific image-guided transcriptomics identifies complex injuries caused by ischemic acute kidney injury in mice. Commun Biol 2019; 2:326. [PMID: 31508501 PMCID: PMC6718519 DOI: 10.1038/s42003-019-0571-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 08/09/2019] [Indexed: 01/20/2023] Open
Abstract
The kidney's inherent complexity has made identifying cell-specific pathways challenging, particularly when temporally associating them with the dynamic pathophysiology of acute kidney injury (AKI). Here, we combine renal cell-specific luciferase reporter mice using a chemoselective luciferin to guide the acquisition of cell-specific transcriptional changes in C57BL/6 background mice. Hydrogen peroxide generation, a common mechanism of tissue damage, was tracked using a peroxy-caged-luciferin to identify optimum time points for immunoprecipitation of labeled ribosomes for RNA-sequencing. Together, these tools revealed a profound impact of AKI on mitochondrial pathways in the collecting duct. In fact, targeting the mitochondria with an antioxidant, ameliorated not only hydrogen peroxide generation, but also significantly reduced oxidative stress and the expression of the AKI biomarker, LCN2. This integrative approach of coupling physiological imaging with transcriptomics and drug testing revealed how the collecting duct responds to AKI and opens new venues for cell-specific predictive monitoring and treatment.
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Affiliation(s)
- Tomoaki Miyazaki
- 1Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98195 USA
- 2Division of Nephrology, Department of Medicine, Showa University, Yokohama, Japan
| | - Sina A Gharib
- 3Computational Medicine Core, Center for Lung Biology, University of Washington, Seattle, WA 98195 USA
| | - Yun-Wei A Hsu
- 1Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98195 USA
| | - Katherine Xu
- 4Renal Division, Department of Medicine, Columbia University, New York, NY 10027 USA
| | - Pavlo Khodakivskyi
- 5Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology of Lausanne (EPFL), Lausanne, Switzerland
| | - Akio Kobayashi
- 1Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98195 USA
| | | | | | | | - Elena Dubikovskaya
- 5Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology of Lausanne (EPFL), Lausanne, Switzerland
| | - Patrick S Page-McCaw
- 9Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Jonathan Barasch
- 4Renal Division, Department of Medicine, Columbia University, New York, NY 10027 USA
| | - Neal Paragas
- 1Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98195 USA
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11
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Gyarmati G, Kadoya H, Moon JY, Burford JL, Ahmadi N, Gill IS, Hong YK, Dér B, Peti-Peterdi J. Advances in Renal Cell Imaging. Semin Nephrol 2019; 38:52-62. [PMID: 29291762 DOI: 10.1016/j.semnephrol.2017.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A great variety of cell imaging technologies are used routinely every day for the investigation of kidney cell types in applications ranging from basic science research to drug development and pharmacology, clinical nephrology, and pathology. Quantitative visualization of the identity, density, and fate of both resident and nonresident cells in the kidney, and imaging-based analysis of their altered function, (patho)biology, metabolism, and signaling in disease conditions, can help to better define pathomechanism-based disease subgroups, identify critical cells and structures that play a role in the pathogenesis, critically needed biomarkers of disease progression, and cell and molecular pathways as targets for novel therapies. Overall, renal cell imaging has great potential for improving the precision of diagnostic and treatment paradigms for individual acute kidney injury or chronic kidney disease patients or patient populations. This review highlights and provides examples for some of the recently developed renal cell optical imaging approaches, mainly intravital multiphoton fluorescence microscopy, and the new knowledge they provide for our better understanding of renal pathologies.
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Affiliation(s)
- Georgina Gyarmati
- Department of Physiology and Neuroscience, Department of Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Hiroyuki Kadoya
- Department of Physiology and Neuroscience, Department of Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA; Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Japan
| | - Ju-Young Moon
- Department of Physiology and Neuroscience, Department of Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA; Division of Nephrology, Department of Internal Medicine, Kyung Hee University, College of Medicine, Seoul, Korea
| | - James L Burford
- Department of Physiology and Neuroscience, Department of Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Nariman Ahmadi
- Institute of Urology, Catherine & Joseph Aresty Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Inderbir S Gill
- Institute of Urology, Catherine & Joseph Aresty Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Young-Kwon Hong
- Department of Surgery and Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Bálint Dér
- Department of Physiology and Neuroscience, Department of Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - János Peti-Peterdi
- Department of Physiology and Neuroscience, Department of Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA.
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12
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Li X, Chen H, Liu F, Chen Y, Zhang H, Wang Z. Accurate Monitoring of Renal Injury State through in Vivo Magnetic Resonance Imaging with Ferric Coordination Polymer Nanodots. ACS OMEGA 2018; 3:4918-4923. [PMID: 30221228 PMCID: PMC6130784 DOI: 10.1021/acsomega.8b00514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 04/25/2018] [Indexed: 06/08/2023]
Abstract
It is highly challenging to detect the pathophysiology of the diseased kidneys and achieve precise diagnosis because there are few in vivo noninvasive imaging techniques to quantitatively assess kidney dysfunction. This longstanding challenge is normally attributed to the limited molecular contrast agents which can be addressed with renal clearable nanoprobes. In this report, we demonstrate the use of magnetic resonance imaging along with renal clearable ferric coordination polymer nanodots (Fe-CPNDs) for in vivo monitoring the kidney dysfunction effects following drug (daunomycin)-induced kidney injury. After intravenous injection of Fe-CPNDs, the change of the MR signal in the kidney can be precisely correlated with local pathological lesion which is demonstrated by renal anatomic details and biochemical examinations of urine and blood. This finding opens the door to the possibility of noninvasively assessing kidney dysfunction and local injuries.
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Affiliation(s)
- Xiaodong Li
- Department
of Radiology, The First Hospital of Jilin
University, Changchun 130021, China
| | - Hongda Chen
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of
Sciences, Changchun 130022, China
- University
of Chinese Academy of Sciences, Beijing 100039, China
| | - Fuyao Liu
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of
Sciences, Changchun 130022, China
| | - Yixin Chen
- Department
of Radiology, The First Hospital of Jilin
University, Changchun 130021, China
| | - Huimao Zhang
- Department
of Radiology, The First Hospital of Jilin
University, Changchun 130021, China
| | - Zhenxin Wang
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute
of Applied Chemistry, Chinese Academy of
Sciences, Changchun 130022, China
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13
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Ow CPC, Ngo JP, Ullah MM, Hilliard LM, Evans RG. Renal hypoxia in kidney disease: Cause or consequence? Acta Physiol (Oxf) 2018; 222:e12999. [PMID: 29159875 DOI: 10.1111/apha.12999] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 11/10/2017] [Accepted: 11/15/2017] [Indexed: 02/06/2023]
Abstract
Tissue hypoxia has been proposed as an important factor in the pathophysiology of both chronic kidney disease (CKD) and acute kidney injury (AKI), initiating and propagating a vicious cycle of tubular injury, vascular rarefaction, and fibrosis and thus exacerbation of hypoxia. Here, we critically evaluate this proposition by systematically reviewing the literature relevant to the following six questions: (i) Is kidney disease always associated with tissue hypoxia? (ii) Does tissue hypoxia drive signalling cascades that lead to tissue damage and dysfunction? (iii) Does tissue hypoxia per se lead to kidney disease? (iv) Does tissue hypoxia precede pathology? (v) Does tissue hypoxia colocalize with pathology? (vi) Does prevention of tissue hypoxia prevent kidney disease? We conclude that tissue hypoxia is a common feature of both AKI and CKD. Furthermore, at least under in vitro conditions, renal tissue hypoxia drives signalling cascades that lead to tissue damage and dysfunction. Tissue hypoxia itself can lead to renal pathology, independent of other known risk factors for kidney disease. There is also some evidence that tissue hypoxia precedes renal pathology, at least in some forms of kidney disease. However, we have made relatively little progress in determining the spatial relationships between tissue hypoxia and pathological processes (i.e. colocalization) or whether therapies targeted to reduce tissue hypoxia can prevent or delay the progression of renal disease. Thus, the hypothesis that tissue hypoxia is a "common pathway" to both AKI and CKD still remains to be adequately tested.
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Affiliation(s)
- C. P. C. Ow
- Cardiovascular Disease Program Biomedicine Discovery Institute and Department of Physiology Monash University Melbourne Vic. Australia
| | - J. P. Ngo
- Cardiovascular Disease Program Biomedicine Discovery Institute and Department of Physiology Monash University Melbourne Vic. Australia
| | - M. M. Ullah
- Cardiovascular Disease Program Biomedicine Discovery Institute and Department of Physiology Monash University Melbourne Vic. Australia
| | - L. M. Hilliard
- Cardiovascular Disease Program Biomedicine Discovery Institute and Department of Physiology Monash University Melbourne Vic. Australia
| | - R. G. Evans
- Cardiovascular Disease Program Biomedicine Discovery Institute and Department of Physiology Monash University Melbourne Vic. Australia
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14
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Dunn KW, Sutton TA, Sandoval RM. Live-Animal Imaging of Renal Function by Multiphoton Microscopy. ACTA ACUST UNITED AC 2018; 83:12.9.1-12.9.25. [PMID: 29345326 DOI: 10.1002/cpcy.32] [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] [Indexed: 12/17/2022]
Abstract
Intravital microscopy, microscopy of living animals, is a powerful research technique that combines the resolution and sensitivity found in microscopic studies of cultured cells with the relevance and systemic influences of cells in the context of the intact animal. The power of intravital microscopy has recently been extended with the development of multiphoton fluorescence microscopy systems capable of collecting optical sections from deep within the kidney at subcellular resolution, supporting high-resolution characterizations of the structure and function of glomeruli, tubules, and vasculature in the living kidney. Fluorescent probes are administered to an anesthetized, surgically prepared animal, followed by image acquisition for up to 3 hr. Images are transferred via a high-speed network to specialized computer systems for digital image analysis. This general approach can be used with different combinations of fluorescent probes to evaluate processes such as glomerular permeability, proximal tubule endocytosis, microvascular flow, vascular permeability, mitochondrial function, and cellular apoptosis/necrosis. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Kenneth W Dunn
- Indiana University School of Medicine, Indianapolis, Indiana
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Abstract
Kidney cell death plays a key role in the progression of life-threatening renal diseases, such as acute kidney injury and chronic kidney disease. Injured and dying epithelial and endothelial cells take part in complex communication with the innate immune system, which drives the progression of cell death and the decrease in renal function. To improve our understanding of kidney cell death dynamics and its impact on renal disease, a study approach is needed that facilitates the visualization of renal function and morphology in real time. Intravital multiphoton microscopy of the kidney has been used for more than a decade and made substantial contributions to our understanding of kidney physiology and pathophysiology. It is a unique tool that relates renal structure and function in a time- and spatial-dependent manner. Basic renal function, such as microvascular blood flow regulation and glomerular filtration, can be determined in real time and homeostatic alterations, which are linked inevitably to cell death and can be depicted down to the subcellular level. This review provides an overview of the available techniques to study kidney dysfunction and inflammation in terms of cell death in vivo, and addresses how this novel approach can be used to improve our understanding of cell death dynamics in renal disease.
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Pannabecker TL. Renal vascular pericytes: long overlooked and poorly understood, but clearly important, and what about those regulatory pathways? Am J Physiol Renal Physiol 2017; 314:F67-F69. [PMID: 28971993 DOI: 10.1152/ajprenal.00468.2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Thomas L Pannabecker
- Department of Physiology, Banner-University Medical Center, University of Arizona , Tucson, Arizona
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Abstract
PURPOSE OF REVIEW The review aims to provide a brief summary and evaluation of the current state of research that uses multiphoton fluorescence microscopy for intravital kidney imaging. RECENT FINDINGS Direct visualization of the glomerular filter, proximal and distal tubule segments, and the renal vasculature in the living, intact kidney in zebrafish, mouse, and rat models with high temporal and spatial resolution provided new insights into the function of the normal and diseased kidney. New technical developments in fluorescence excitation and detection, in combination with transgenic animal models for cell function and fate mapping, and serial imaging of the same glomerulus in the same animal over several days further advanced the field of nephrology research, and the understanding of disease mechanisms. SUMMARY Intravital multiphoton imaging has solved many critical technical barriers in kidney research and allowed the dynamic portrayal of the structure and function of various renal cell types in vivo. It has become a widely used research technique, with significant past achievements, and tremendous potential for future development and applications for the study and better understanding of kidney diseases.
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Schießl IM, Castrop H. Deep insights: intravital imaging with two-photon microscopy. Pflugers Arch 2016; 468:1505-16. [PMID: 27352273 DOI: 10.1007/s00424-016-1832-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 04/26/2016] [Indexed: 01/03/2023]
Abstract
Intravital multiphoton microscopy is widely used to assess the structure and function of organs in live animals. Although different tissues vary in their accessibility for intravital multiphoton imaging, considerable progress has been made in the imaging quality of all tissues due to substantial technical improvements in the relevant imaging components, such as optics, excitation laser, detectors, and signal analysis software. In this review, we provide an overview of the technical background of intravital multiphoton microscopy. Then, we note a few seminal findings that were made through the use of multiphoton microscopy. Finally, we address the technical limitations of the method and provide an outlook for how these limitations may be overcome through future technical developments.
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Affiliation(s)
- Ina Maria Schießl
- Institute of Physiology, University of Regensburg, Universitätsstr. 31, 93040, Regensburg, Germany.
| | - Hayo Castrop
- Institute of Physiology, University of Regensburg, Universitätsstr. 31, 93040, Regensburg, Germany
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Autophagy, Innate Immunity and Tissue Repair in Acute Kidney Injury. Int J Mol Sci 2016; 17:ijms17050662. [PMID: 27153058 PMCID: PMC4881488 DOI: 10.3390/ijms17050662] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/14/2016] [Accepted: 04/20/2016] [Indexed: 01/09/2023] Open
Abstract
Kidney is a vital organ with high energy demands to actively maintain plasma hemodynamics, electrolytes and water homeostasis. Among the nephron segments, the renal tubular epithelium is endowed with high mitochondria density for their function in active transport. Acute kidney injury (AKI) is an important clinical syndrome and a global public health issue with high mortality rate and socioeconomic burden due to lack of effective therapy. AKI results in acute cell death and necrosis of renal tubule epithelial cells accompanied with leakage of tubular fluid and inflammation. The inflammatory immune response triggered by the tubular cell death, mitochondrial damage, associative oxidative stress, and the release of many tissue damage factors have been identified as key elements driving the pathophysiology of AKI. Autophagy, the cellular mechanism that removes damaged organelles via lysosome-mediated degradation, had been proposed to be renoprotective. An in-depth understanding of the intricate interplay between autophagy and innate immune response, and their roles in AKI pathology could lead to novel therapies in AKI. This review addresses the current pathophysiology of AKI in aspects of mitochondrial dysfunction, innate immunity, and molecular mechanisms of autophagy. Recent advances in renal tissue regeneration and potential therapeutic interventions are also discussed.
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Abstract
This article summarizes the past, present, and future promise of multiphoton excitation fluorescence microscopy for intravital kidney imaging. During the past 15years, several high-power visual research approaches have been developed using multiphoton imaging to study the normal functions of the healthy, intact, living kidney, and the various molecular and cellular mechanisms of the development of kidney diseases. In this review, the main focus will be on intravital multiphoton imaging of the glomerulus, the structure and function of the glomerular filtration barrier, especially the podocyte. Examples will be given for the combination of two powerful research tools, in vivo multiphoton imaging and mouse genetics using commercially available whole animal models for the detailed characterization of glomerular cell types, their function and fate, and for the better understanding of the molecular mechanisms of glomerular pathologies. One of the new modalities of multiphoton imaging, serial imaging of the same glomerulus in the same animal over several days will be emphasized for its potential for further advancing the field of nephrology research.
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Affiliation(s)
- János Peti-Peterdi
- Departments of Physiology and Biophysics, and Medicine, Zilkha Neurogenetic Institute, ZNI355, University of Southern California, 1501 San Pablo Street, Los Angeles, CA 90033, USA.
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Mayrhofer JM, Haiss F, Haenni D, Weber S, Zuend M, Barrett MJP, Ferrari KD, Maechler P, Saab AS, Stobart JL, Wyss MT, Johannssen H, Osswald H, Palmer LM, Revol V, Schuh CD, Urban C, Hall A, Larkum ME, Rutz-Innerhofer E, Zeilhofer HU, Ziegler U, Weber B. Design and performance of an ultra-flexible two-photon microscope for in vivo research. BIOMEDICAL OPTICS EXPRESS 2015; 6:4228-37. [PMID: 26600989 PMCID: PMC4646533 DOI: 10.1364/boe.6.004228] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 09/28/2015] [Accepted: 09/28/2015] [Indexed: 05/12/2023]
Abstract
We present a cost-effective in vivo two-photon microscope with a highly flexible frontend for in vivo research. Our design ensures fast and reproducible access to the area of interest, including rotation of imaging plane, and maximizes space for auxiliary experimental equipment in the vicinity of the animal. Mechanical flexibility is achieved with large motorized linear stages that move the objective in the X, Y, and Z directions up to 130 mm. 360° rotation of the frontend (rotational freedom for one axis) is achieved with the combination of a motorized high precision bearing and gearing. Additionally, the modular design of the frontend, based on commercially available optomechanical parts, allows straightforward updates to future scanning technologies. The design exceeds the mobility of previous movable microscope designs while maintaining high optical performance.
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Affiliation(s)
- Johannes M. Mayrhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Florent Haiss
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- IZKF Aachen, Medical Faculty of the RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
- Institute for Neuropathology, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Dominik Haenni
- Center for Microscopy and Image Analysis, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Stefan Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Matthew J. P. Barrett
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Philipp Maechler
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Aiman S. Saab
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Jillian L. Stobart
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Matthias T. Wyss
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Helge Johannssen
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Harald Osswald
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Lucy M. Palmer
- Florey Instittue, University of Melbourne, 30 Royal Parade, Melbourne, Victoria, 3010, Australia
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Vincent Revol
- CSEM Suisse d’Electronique et de Microtechnique, Technoparkstrasse 1, 8005 Zurich, Switzerland
| | - Claus-Dieter Schuh
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Claus Urban
- CSEM Suisse d’Electronique et de Microtechnique, Technoparkstrasse 1, 8005 Zurich, Switzerland
| | - Andrew Hall
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Matthew E. Larkum
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Edith Rutz-Innerhofer
- CSEM Suisse d’Electronique et de Microtechnique, Technoparkstrasse 1, 8005 Zurich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Urs Ziegler
- Center for Microscopy and Image Analysis, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Matejovic M, Ince C, Chawla LS, Blantz R, Molitoris BA, Rosner MH, Okusa MD, Kellum JA, Ronco C. Renal Hemodynamics in AKI: In Search of New Treatment Targets. J Am Soc Nephrol 2015; 27:49-58. [PMID: 26510884 DOI: 10.1681/asn.2015030234] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Novel therapeutic interventions are required to prevent or treat AKI. To expedite progress in this regard, a consensus conference held by the Acute Dialysis Quality Initiative was convened in April of 2014 to develop recommendations for research priorities and future directions. Here, we highlight the concepts related to renal hemodynamics in AKI that are likely to reveal new treatment targets on investigation. Overall, we must better understand the interactions between systemic, total renal, and glomerular hemodynamics, including the role of tubuloglomerular feedback. Furthermore, the net consequences of therapeutic maneuvers aimed at restoring glomerular filtration need to be examined in relation to the nature, magnitude, and duration of the insult. Additionally, microvascular blood flow heterogeneity in AKI is now recognized as a common occurrence; timely interventions to preserve the renal microcirculatory flow may interrupt the downward spiral of injury toward progressive kidney failure and should, therefore, be investigated. Finally, development of techniques that permit an integrative physiologic approach, including direct visualization of renal microvasculature and measurement of oxygen kinetics and mitochondrial function in intact tissue in all nephron segments, may provide new insights into how the kidney responds to various injurious stimuli and allow evaluation of new therapeutic strategies.
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Affiliation(s)
- Martin Matejovic
- First Medical Department and Biomedical Centre, Faculty of Medicine in Plzen, Charles University in Prague, Teaching Hospital in Plzen, Plzen, Czech Republic
| | - Can Ince
- Department of Intensive Care, Erasmus Medical Center University Hospital, Rotterdam, The Netherlands
| | - Lakhmir S Chawla
- Department of Medicine, Division of Intensive Care Medicine and Division of Nephrology, Veterans Affairs Medical Center, Washington, DC
| | - Roland Blantz
- Nephrology-Hypertension Division, University of California, San Diego School of Medicine and Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Bruce A Molitoris
- Department of Medicine, Division of Nephrology and Department of Cellular and Integrative Physiology, Indiana University School of Medicine and the Rouderbush Veterans Affairs Medical Center, Indianapolis, Indiana
| | - Mitchell H Rosner
- Division of Nephrology, Center for Immunity, Inflammation and Regenerative Medicine, University of Virginia Health System, Charlottesville, Virginia;
| | - Mark D Okusa
- Division of Nephrology, Center for Immunity, Inflammation and Regenerative Medicine, University of Virginia Health System, Charlottesville, Virginia
| | - John A Kellum
- Center for Critical Care Nephrology and Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Claudio Ronco
- Department of Nephrology Dialysis and Transplantation, San Bortolo Hospital and the International Renal Research Institute, Vicenza, Italy
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Endres BT, Staruschenko A, Schulte M, Geurts AM, Palygin O. Two-photon Imaging of Intracellular Ca2+ Handling and Nitric Oxide Production in Endothelial and Smooth Muscle Cells of an Isolated Rat Aorta. J Vis Exp 2015:e52734. [PMID: 26132549 DOI: 10.3791/52734] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Calcium is a very important regulator of many physiological processes in vascular tissues. Most endothelial and smooth muscle functions highly depend on changes in intracellular calcium ([Ca(2+)]i) and nitric oxide (NO). In order to understand how [Ca(2+)]i, NO and downstream molecules are handled by a blood vessel in response to vasoconstrictors and vasodilators, we developed a novel technique that applies calcium-labeling (or NO-labeling) dyes with two photon microscopy to measure calcium handling (or NO production) in isolated blood vessels. Described here is a detailed step-by-step procedure that demonstrates how to isolate an aorta from a rat, label calcium or NO within the endothelial or smooth muscle cells, and image calcium transients (or NO production) using a two photon microscope following physiological or pharmacological stimuli. The benefits of using the method are multi-fold: 1) it is possible to simultaneously measure calcium transients in both endothelial cells and smooth muscle cells in response to different stimuli; 2) it allows one to image endothelial cells and smooth muscle cells in their native setting; 3) this method is very sensitive to intracellular calcium or NO changes and generates high resolution images for precise measurements; and 4) described approach can be applied to the measurement of other molecules, such as reactive oxygen species. In summary, application of two photon laser emission microscopy to monitor calcium transients and NO production in the endothelial and smooth muscle cells of an isolated blood vessel has provided high quality quantitative data and promoted our understanding of the mechanisms regulating vascular function.
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Affiliation(s)
- Bradley T Endres
- Departments of Physiology, Medical College of Wisconsin; Human and Molecular Genetics Center, Medical College of Wisconsin
| | | | | | - Aron M Geurts
- Departments of Physiology, Medical College of Wisconsin; Human and Molecular Genetics Center, Medical College of Wisconsin; Cardiovascular Center, Medical College of Wisconsin
| | - Oleg Palygin
- Departments of Physiology, Medical College of Wisconsin
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25
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Novel in vivo techniques to visualize kidney anatomy and function. Kidney Int 2015; 88:44-51. [PMID: 25738253 PMCID: PMC4490063 DOI: 10.1038/ki.2015.65] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 01/05/2015] [Accepted: 01/06/2015] [Indexed: 12/11/2022]
Abstract
Intravital imaging using multiphoton microscopy (MPM) has become an increasingly popular and widely used experimental technique in kidney research over the past few years. MPM allows deep optical sectioning of the intact, living kidney tissue with submicron resolution which is unparalleled among intravital imaging approaches. MPM has solved a long-standing critical technical barrier in renal research to study several complex and inaccessible cell types and anatomical structures in vivo in their native environment. Comprehensive and quantitative kidney structure and function MPM studies helped our better understanding of the cellular and molecular mechanisms of the healthy and diseased kidney. This review summarizes recent in vivo MPM studies with a focus on the glomerulus and the filtration barrier, although select, glomerulus-related renal vascular and tubular functions are also mentioned. The latest applications of serial MPM of the same glomerulus in vivo, in the intact kidney over several days, during the progression of glomerular disease are discussed. This visual approach, in combination with genetically encoded fluorescent markers of cell lineage, has helped to track the fate and function (e.g. cell calcium changes) of single podocytes during the development of glomerular pathologies, and provided visual proof for the highly dynamic rather than static nature of the glomerular environment. Future intravital imaging applications have the promise to further push the limits of optical microscopy, and to advance our understanding of the mechanisms of kidney injury. Also, MPM will help to study new mechanisms of tissue repair and regeneration, a cutting edge area of kidney research.
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