1
|
Krogager ME, Dahl RH, Poulsgaard L, Fugleholm K, Sehested T, Mikkelsen R, Tranum-Jensen J, Mathiesen TI, Benndorf G. Combined cone-beam CT imaging and microsurgical dissection of cadaver specimens to study cerebral venous anatomy: a technical note. Surg Radiol Anat 2023; 45:1177-1184. [PMID: 37542573 PMCID: PMC10514096 DOI: 10.1007/s00276-023-03195-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 06/28/2023] [Indexed: 08/07/2023]
Abstract
PURPOSE Cadaver dissections and X-ray based 3D angiography are considered gold standards for studying neurovascular anatomy. We sought to develop a model that utilize the combination of both these techniques to improve current tools for anatomical research, teaching and preoperative surgical planning, particularly addressing the venous system of the brain. MATERIALS AND METHODS Seven ethanol-fixed human cadaveric heads and one arm were injected with a latex-barium mixture into the internal jugular veins and the brachial artery. After the ethanol-based fixation, specimens were scanned by high-resolution cone-beam CT and images were post-processed on a 3D-workstation. Subsequent, microsurgical dissections were performed by an experienced neurosurgeon and venous anatomy was compared with relevant 3D venograms. RESULTS Latex-barium mixtures resulted in a homogenous cast with filling of the cerebral venous structures down to 150 μm in diameter. The ethanol-based preparation of the cadaveric brains allowed for near-realistic microsurgical maneuverability during dissection. The model improves assessment of the venous system for anatomical education and hands-on surgical training. CONCLUSION To our knowledge we describe the first preparation method which combines near-realistic microsurgical dissection of human heads with high-resolution 3D imaging of the cerebral venous system in the same specimens.
Collapse
Affiliation(s)
- Markus E Krogager
- Department of Neurosurgery, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark.
| | - Rasmus H Dahl
- Department of Radiology, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
- Department of Radiology, Hvidovre Hospital, Copenhagen, Denmark
| | - Lars Poulsgaard
- Department of Neurosurgery, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Kåre Fugleholm
- Department of Neurosurgery, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Tom Sehested
- Department of Neurosurgery, Aarhus University Hospital, Aarhus, Denmark
| | - Ronni Mikkelsen
- Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Jørgen Tranum-Jensen
- Department of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Tiit I Mathiesen
- Department of Neurosurgery, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Goetz Benndorf
- Department of Radiology, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
- Department of Radiology, Baylor College of Medicine, Houston, TX, USA
| |
Collapse
|
2
|
Hartmann JP, Dahl RH, Nymand S, Munch GW, Ryrsø CK, Pedersen BK, Thaning P, Mortensen SP, Berg RMG, Iepsen UW. Regulation of the microvasculature during small muscle mass exercise in chronic obstructive pulmonary disease vs. chronic heart failure. Front Physiol 2022; 13:979359. [PMID: 36134330 PMCID: PMC9483770 DOI: 10.3389/fphys.2022.979359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/08/2022] [Indexed: 11/21/2022] Open
Abstract
Aim: Skeletal muscle convective and diffusive oxygen (O2) transport are peripheral determinants of exercise capacity in both patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). We hypothesised that differences in these peripheral determinants of performance between COPD and CHF patients are revealed during small muscle mass exercise, where the cardiorespiratory limitations to exercise are diminished. Methods: Eight patients with moderate to severe COPD, eight patients with CHF (NYHA II), and eight age- and sex-matched controls were studied. We measured leg blood flow (Q̇leg) by Doppler ultrasound during submaximal one-legged knee-extensor exercise (KEE), while sampling arterio-venous variables across the leg. The capillary oxyhaemoglobin dissociation curve was reconstructed from paired femoral arterial-venous oxygen tensions and saturations, which enabled the estimation of O2 parameters at the microvascular level within skeletal muscle, so that skeletal muscle oxygen conductance (DSMO2) could be calculated and adjusted for flow (DSMO2/Q̇leg) to distinguish convective from diffusive oxygen transport. Results: During KEE, Q̇leg increased to a similar extent in CHF (2.0 (0.4) L/min) and controls (2.3 (0.3) L/min), but less in COPD patients (1.8 (0.3) L/min) (p <0.03). There was no difference in resting DSMO2 between COPD and CHF and when adjusting for flow, the DSMO2 was higher in both groups compared to controls (COPD: 0.97 (0.23) vs. controls 0.63 (0.24) mM/kPa, p= 0.02; CHF 0.98 (0.11) mM/kPa vs. controls, p= 0.001). The Q̇-adjusted DSMO2 was not different in COPD and CHF during KEE (COPD: 1.19 (0.11) vs. CHF: 1.00 (0.18) mM/kPa; p= 0.24) but higher in COPD vs. controls: 0.87 (0.28) mM/kPa (p= 0.02), and only CHF did not increase Q̇-adjusted DSMO2 from rest (p= 0.2). Conclusion: Disease-specific factors may play a role in peripheral exercise limitation in patients with COPD compared with CHF. Thus, low convective O2 transport to contracting muscle seemed to predominate in COPD, whereas muscle diffusive O2 transport was unresponsive in CHF.
Collapse
Affiliation(s)
- Jacob Peter Hartmann
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Rasmus H Dahl
- Department of Radiology, Hvidovre Hospital, Copenhagen, Denmark.,Department of Radiology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Stine Nymand
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gregers W Munch
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Camilla K Ryrsø
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Pulmonary and Infectious Diseases, Copenhagen University Hospital, North Zealand, Hillerød, Denmark
| | - Bente K Pedersen
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Pia Thaning
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Respiratory Medicine, Copenhagen University Hospital, Hvidovre Hospital, Copenhagen, Denmark
| | - Stefan P Mortensen
- Department of Cardiovascular and Renal Research, University of Southern Denmark, Copenhagen, Denmark
| | - Ronan M G Berg
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, United Kingdom
| | - Ulrik Winning Iepsen
- Centre for Physical Activity Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Anaesthesiology and Intensive Care, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark
| |
Collapse
|
3
|
Kristensen AW, Greve AM, Dahl RH, Perch M, Mortensen J, Berg RMG. Evidence of unilateral diaphragmatic paralysis on lung scintigraphy after double lung transplantation: impact on lung function and survival. Scand J Clin Lab Invest 2020; 80:454-455. [PMID: 33000658 DOI: 10.1080/00365513.2020.1781244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Anna Warncke Kristensen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Anders Møller Greve
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus H Dahl
- Department of Neuroanaesthesiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Michael Perch
- Department of Cardiology, Section for Lung Transplantation, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jann Mortensen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Medicine, The National Hospital, Torshavn, Faroe Islands
| | - Ronan M G Berg
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
4
|
Kristensen AW, Berg RM, Greve AM, Dahl RH, Perch M, Mortensen J. Survival in patients with scintigraphic evidence of pulmonary thromboembolism 12 weeks after double lung transplantation. J Heart Lung Transplant 2020; 39:719-721. [DOI: 10.1016/j.healun.2020.02.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/29/2020] [Accepted: 02/20/2020] [Indexed: 10/24/2022] Open
|
5
|
Dahl RH, Taudorf S, Bailey DM, Møller K, Berg RMG. A method for modelling the oxyhaemoglobin dissociation curve at the level of the cerebral capillary in humans. Exp Physiol 2020; 105:1063-1070. [PMID: 32436618 DOI: 10.1113/ep088615] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 05/18/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Can the change in haemoglobin's affinity for oxygen in the human cerebral circulation be modelled in vivo? What is the main finding and its importance? We provide a novel method for modelling the oxyhaemoglobin dissociation curve at the cerebral capillary level in humans, so that the cerebral capillary and mitochondrial oxygen tensions can reliably be estimated. This may be useful in future human-experimental studies on cerebral oxygen transport. ABSTRACT We provide a method for modelling the oxyhaemoglobin dissociation curve (ODC) in the cerebral capillary in humans. In contrast to most previous approaches, our method involves the construction of an averaged ODC based on paired arterial-jugular venous blood gas values, which enables the estimation of oxygen parameters in cerebral capillary blood. The method was used to determine the mean cerebral capillary oxygen saturation and tension from data previously collected from 30 healthy volunteers. The averaged ODC provided systematically higher capillary oxygen tensions than when assuming a 'fixed' standard arterial ODC. When the averaged and measured arterial ODC were used for constructing the capillary ODC, similar values were obtained during resting breathing, but not when the arterial ODC was modulated by hypocapnia. The findings suggest that our method for modelling the cerebral capillary ODC provides robust and physiologically reliable estimates of the cerebral capillary oxygen tension, which may be of use in future studies of cerebral oxygen transport in humans.
Collapse
Affiliation(s)
- Rasmus H Dahl
- Department of Neuroanaesthesiology, University Hospital Rigshospitalet, Copenhagen, Denmark.,Department of Radiology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Sarah Taudorf
- Department of Neurology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Kirsten Møller
- Department of Neuroanaesthesiology, University Hospital Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ronan M G Berg
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Physiology, Nuclear Medicine & PET and Centre for Physical Activity Research, University Hospital Rigshospitalet, Copenhagen, Denmark
| |
Collapse
|
6
|
Dahl RH, Berg RMG, Taudorf S, Bailey DM, Lundby C, Christensen M, Larsen FS, Møller K. Transcerebral exchange kinetics of large neutral amino acids during acute inspiratory hypoxia in humans. Scand J Clin Lab Invest 2019; 79:595-600. [PMID: 31657241 DOI: 10.1080/00365513.2019.1683762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Hypoxaemia is present in many critically ill patients, and may contribute to encephalopathy. Changes in the passage of large neutral amino acids (LNAAs) across the blood-brain barrier (BBB) with an increased cerebral influx of aromatic amino acids into the brain may concurrently be present and also contribute to encephalopathy, but it has not been established whether hypoxaemia per se may trigger such changes. We measured cerebral blood flow (CBF) in 11 healthy men using the Kety-Schmidt technique and obtained paired arterial and jugular-venous blood samples for the determination of LNAAs by high performance liquid chromatography at baseline and after 9 hours of poikilocapnic normobaric hypoxia (12% O2). Transcerebral net exchange was determined by the Fick principle, and transport of LNAAs across the BBB was determined mathematically. Hypoxia increased both the systemic and corresponding cerebral delivery of the aromatic amino acid phenylalanine, and the branched-chain amino acids leucine and isoleucine. Despite this, the transcerebral net exchange values and mathematically derived brain extracellular concentrations for all LNAAs were unaffected. In conclusion, the observed changes in circulating LNAAs triggered by hypoxaemia do not affect the transcerebral exchange kinetics of LNAAs to such an extent that their brain extracellular concentrations are affected.
Collapse
Affiliation(s)
- Rasmus H Dahl
- Department of Neuroanaesthesiology, Rigshospitalet, Copenhagen, Denmark
| | - Ronan M G Berg
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontyprid, UK
| | - Sarah Taudorf
- Department of Neurology 2082, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontyprid, UK
| | - Carsten Lundby
- Centre for Physical Activity Research, Rigshospitalet, Copenhagen, Denmark
| | - Mette Christensen
- Department of Clinical Genetics, Rigshospitalet, Copenhagen, Denmark
| | - Fin S Larsen
- Department of Hepatology, Rigshospitalet, Copenhagen, Denmark
| | - Kirsten Møller
- Department of Neuroanaesthesiology, Rigshospitalet, Copenhagen, Denmark
| |
Collapse
|
7
|
Dahl RH, Holtmannspötter M, Gutte H, Cortsen M, Hauerberg J, Benndorf G. Snaring of a Glued Microcatheter During Embolization of an Arteriovenous Malformation with N-Butyl Cyanoacrylate. World Neurosurg 2018; 120:343-348. [DOI: 10.1016/j.wneu.2018.08.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 11/16/2022]
|
8
|
Berg RMG, Taudorf S, Bailey DM, Dahl RH, Lundby C, Møller K. Transcerebral net exchange of vasoactive peptides and catecholamines during lipopolysaccharide-induced systemic inflammation in healthy humans. Can J Physiol Pharmacol 2017; 96:313-316. [PMID: 28898586 DOI: 10.1139/cjpp-2017-0266] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The systemic inflammatory response triggered by lipopolysaccharide (LPS) is associated with cerebral vasoconstriction, but the underlying mechanisms are unknown. We therefore examined whether a 4-hour intravenous LPS infusion (0.3 ng·kg-1) induces any changes in the transcerebral net exchange of the vasoactive peptides endothelin-1 (ET-1) and calcitonin-gene related peptide (CGRP) and catecholamines in human volunteers. Cerebral blood flow was measured by the Kety-Schmidt technique, and paired arterial-to-jugular venous blood samples were obtained for estimating the transcerebral exchange of ET-1, CGRP, and catecholamines by the Fick principle in 12 volunteers before and after LPS infusion. The cerebrovascular release of ET-1 was enhanced, whereas the transcerebral net exchange of CGRP and catecholamines was unaffected. Our findings thus point towards locally produced ET-1 within the cerebrovasculature as a contributor to cerebral vasoconstriction after LPS infusion.
Collapse
Affiliation(s)
- Ronan M G Berg
- a Centre of Inflammation & Metabolism, University Hospital Rigshospitalet, Copenhagen, Denmark.,b Department of Clinical Physiology & Nuclear Medicine, Bispebjerg and Frederiksberg Hospitals, Copenhagen, Denmark
| | - Sarah Taudorf
- a Centre of Inflammation & Metabolism, University Hospital Rigshospitalet, Copenhagen, Denmark.,c Department of Neurology 2082, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Damian M Bailey
- d Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Rasmus H Dahl
- e Department of Neuroanaesthesiology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Carsten Lundby
- f Zürich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland
| | - Kirsten Møller
- a Centre of Inflammation & Metabolism, University Hospital Rigshospitalet, Copenhagen, Denmark.,e Department of Neuroanaesthesiology, University Hospital Rigshospitalet, Copenhagen, Denmark
| |
Collapse
|
9
|
Dahl RH, Berg RMG, Taudorf S, Bailey DM, Lundby C, Larsen FS, Møller K. A reassessment of the blood-brain barrier transport of large neutral amino acids during acute systemic inflammation in humans. Clin Physiol Funct Imaging 2017; 38:656-662. [PMID: 28795486 DOI: 10.1111/cpf.12463] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 07/03/2017] [Indexed: 11/30/2022]
Abstract
We reassessed data from a previous study on the transcerebral net exchange of large neutral amino acids (LNAAs) using a novel mathematical model of blood-brain barrier (BBB) transport. The study included twelve healthy volunteers who received a 4-h intravenous lipopolysaccharide (LPS) infusion (total dose: 0·3 ng/kg), a human experimental model of the systemic inflammatory response during the early stages of sepsis. Cerebral blood flow and arterial-to-jugular venous LNAA concentrations were measured prior to and after LPS, and the BBB transport and brain extracellular concentrations of LNAAs were calculated. The arterial concentration and unidirectional cerebral influx of phenylalanine increased after LPS. The BBB transport of tyrosine was unaffected, while its concentration in the brain extracellular fluid increased. These findings suggest that LPS infusion leads to an increased cerebral uptake of phenylalanine, which is then metabolized to tyrosine. This may reflect a neuroprotective mechanism that 'detoxifies' excess intracerebral phenylalanine in the clinical setting of sepsis.
Collapse
Affiliation(s)
- Rasmus H Dahl
- Neurointensive Care Unit 2093, Department of Neuroanaesthesiology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Ronan M G Berg
- Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospitals, Copenhagen, Denmark.,Centre of Inflammation and Metabolism, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Sarah Taudorf
- Centre of Inflammation and Metabolism, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Treforest, UK
| | - Carsten Lundby
- Center for Integrative Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Fin S Larsen
- Department of Hepatology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Kirsten Møller
- Neurointensive Care Unit 2093, Department of Neuroanaesthesiology, University Hospital Rigshospitalet, Copenhagen, Denmark.,Centre of Inflammation and Metabolism, University Hospital Rigshospitalet, Copenhagen, Denmark
| |
Collapse
|
10
|
White P, Doctor RB, Dahl RH, Chen J. Coincident microvillar actin bundle disruption and perinuclear actin sequestration in anoxic proximal tubule. Am J Physiol Renal Physiol 2000; 278:F886-93. [PMID: 10836976 DOI: 10.1152/ajprenal.2000.278.6.f886] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present studies investigated acute disruption of microvillar actin cytoskeleton and actin association with other cytoskeletal components in ATP-depleted rabbit proximal tubular cells. Video-enhanced differential-interference contrast microscopy and confocal microscopy were used to follow the fate of F-actin during the disruption of microvilli. Within individual cells, all microvilli collapsed simultaneously. Microvillar actin filaments underwent a parallel decrease in length. Using a sequential cytoskeletal extraction protocol and electron microscopy, we revealed in the present studies the coincident sequestration of a distinct, perinuclear pool of actin that was primarily absent in control cells. Actin sequestration progressed in a duration-dependent manner, occurring as early as 15 min of anoxia when cellular ATP dropped to <5% of control level. Phalloidin staining and depolymerization treatment showed the majority (>90%) of this sequestered actin to be F-actin. A microvillar actin bundling protein villin was also sequestered in the same perinuclear complex of anoxic proximal tubules. In conclusion, the present results demonstrate a coincident microvillar actin bundle disruption and the perinuclear sequestration of F-actin in ATP-depleted proximal tubular cells.
Collapse
Affiliation(s)
- P White
- Department of Life Sciences, Indiana State University, Terre Haute 47809, USA
| | | | | | | |
Collapse
|
11
|
Abstract
Intrahepatic bile ducts (BD) are a critical target of injury in the postischemic liver. Decreased vascular perfusion causes characteristic changes in the morphology of the ductular epithelia including a loss of secondary membrane structures and a decrease in plasma membrane surface area. Using adenosine triphosphate (ATP) depletion of cultured normal rat cholangiocytes (NRC) to model ischemic ducts, the present studies examined the fate of apical membrane proteins to determine whether membrane recycling might contribute to rapid functional recovery. Apical proteins, including gamma-glutamyl transpeptidase (GGT), Na(+)-glucose cotransporter (SGLT1), and apically biotinylated proteins, were not shed into the luminal space during ATP depletion. Instead, labeling of surface proteins after ATP depletion showed a significant decrease in GGT and SGLT1, consistent with membrane internalization. Similarly, z-axis confocal microscopy of biotinylated apical proteins also showed protein internalization. During ATP recovery, SGLT1 transport activity remained profoundly depressed even after 24 hours of recovery, indicating that the function of the internalized apical proteins is not rapidly recovered. These studies suggest that the membrane internalization in ATP-depleted cholangiocytes is a unidirectional process that contributes to prolonged functional deficits after restoration of normal cellular ATP levels. This sustained decrease in transport capacity may contribute to the development of ductular injury in postischemic livers.
Collapse
Affiliation(s)
- R B Doctor
- University of Colorado Health Sciences Center, Denver, CO 80262, USA.
| | | | | | | | | | | |
Collapse
|
12
|
Gumpricht E, Devereaux MW, Dahl RH, Sokol RJ. Glutathione status of isolated rat hepatocytes affects bile acid-induced cellular necrosis but not apoptosis. Toxicol Appl Pharmacol 2000; 164:102-11. [PMID: 10739750 DOI: 10.1006/taap.2000.8894] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An accumulation of hydrophobic bile acids is implicated in the pathogenesis of cholestatic liver diseases. In the present study, we determined if hydrophobic bile acid-induced cellular injury compromised hepatocyte glutathione (GSH) status, and if modulating intracellular GSH levels prevented or facilitated bile acid-induced cellular cytotoxicities. Freshly isolated rat hepatocytes incubated with >/=125 microM of the hydrophobic bile acid, glycochenodeoxycholic acid (GCDC), underwent a time- and dose-dependent decrease of intracellular GSH levels by 4-h incubation. This loss of intracellular GSH was not associated with an increase of intracellular GSH disulfide (GSSG). Rather, GCDC stimulated the dose-dependent accumulation of extracellular GSSG. The mechanism for extracellular GSSG accumulation by GCDC was through increased efflux of reduced GSH from hepatocytes into the media, where it subsequently oxidized to GSSG. Treatment of hepatocytes with GCDC (0-750 microM) did not directly alter GSH-dependent enzyme activities. The reduction of intracellular GSH with 125 microM GCDC correlated with extensive apoptosis at this concentration as determined by fluorescence microscopy of DAPI (4, 6-diamindino-2-phenylindole hydrochloride)-stained nuclei. Higher concentrations of GCDC (>/=500 microM) favored cellular necrosis and lipid peroxidation. Depleting GSH by treating hepatocytes with 1-bromoheptane increased their sensitivity toward GCDC-induced cellular necrosis, but not apoptosis. However, enhancing the hepatocyte GSH content by supplementation with GSH-ethylester (GSH-EE) failed to protect hepatocytes against either mode of cellular death. In conclusion, while GCDC-induced cytotoxicities were associated with an increased efflux of GSH from rat hepatocytes, GSH status modulated GCDC-induced necrosis, but not apoptosis.
Collapse
Affiliation(s)
- E Gumpricht
- Center for Human Nutrition, University of Colorado School of Medicine and The Children's Hospital, Denver, Colorado, 80218, USA
| | | | | | | |
Collapse
|
13
|
Abstract
Cholangiocytes contribute significantly to bile formation through the vectorial secretion of water and electrolytes and are a focal site of injury in a number of diseases including liver ischemia and post-transplantation liver failure. Using ischemia in intact liver and adenosine triphosphate (ATP) depletion in cultured cells to model cholangiocyte injury, these studies examined the effects of metabolic inhibition on cholangiocyte viability and structure. During 120 minutes of ischemia or ATP depletion, cell viability and tight junctional integrity in cholangiocytes were maintained. However, both the in vivo and in vitro models displayed striking alterations in the secondary structure of the plasma membrane. After 120 minutes, the basolateral (BL) interdigitations were diminished and the apical (Ap) microvilli were significantly decreased in number. The BL and Ap membrane surface areas decreased by 42 +/- 8% and 63 +/- 2%, respectively. Despite these changes, F-actin remained predominantly localized to the membrane domains. In contrast, in a time course that paralleled the loss of microvilli, the actin-membrane linking protein ezrin progressively dissociated from the cytoskeleton. These studies indicate that cholangiocyte ATP depletion induces characteristic, domain-specific changes in the plasma membrane and implicate alterations in the membrane-cytoskeletal interactions in the initiation of the changes. Pending the re-establishment of the differentiated domains, the loss of specific secondary structures may contribute to impaired vectorial bile duct secretion and postischemic cholestasis.
Collapse
Affiliation(s)
- R B Doctor
- University of Colorado Health Sciences Center, Division of Gastroenterology and Hepatology, Denver, CO 80262, USA.
| | | | | | | |
Collapse
|
14
|
Taylor RS, Jones SM, Dahl RH, Nordeen MH, Howell KE. Characterization of the Golgi complex cleared of proteins in transit and examination of calcium uptake activities. Mol Biol Cell 1997; 8:1911-31. [PMID: 9348533 PMCID: PMC25639 DOI: 10.1091/mbc.8.10.1911] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/1997] [Accepted: 07/28/1997] [Indexed: 02/05/2023] Open
Abstract
To characterize endogenous molecules and activities of the Golgi complex, proteins in transit were > 99% cleared from rat hepatocytes by using cycloheximide (CHX) treatment. The loss of proteins in transit resulted in condensation of the Golgi cisternae and stacks. Isolation of a stacked Golgi fraction is equally efficient with or without proteins in transit [control (CTL SGF1) and cycloheximide (CHX SGF1)]. Electron microscopy and morphometric analysis showed that > 90% of the elements could be positively identified as Golgi stacks or cisternae. Biochemical analysis showed that the cis-, medial-, trans-, and TGN Golgi markers were enriched over the postnuclear supernatant 200- to 400-fold with and 400- to 700-fold without proteins in transit. To provide information on a mechanism for import of calcium required at the later stages of the secretory pathway, calcium uptake into CTL SGF1 and CHX SGF1 was examined. All calcium uptake into CTL SGF1 was dependent on a thapsigargin-resistant pump not resident to the Golgi complex and a thapsigargin-sensitive pump resident to the Golgi. Experiments using CHX SGF1 showed that the thapsigargin-resistant activity was a plasma membrane calcium ATPase isoform in transit to the plasma membrane and the thapsigargin-sensitive pump was a sarcoplasmic/endoplasmic reticulum calcium ATPase isoform. In vivo both of these calcium ATPases function to maintain millimolar levels of calcium within the Golgi lumen.
Collapse
Affiliation(s)
- R S Taylor
- Department of Cellular and Structural Biology, University of Colorado School of Medicine, Denver 80262, USA
| | | | | | | | | |
Collapse
|
15
|
Ford DM, Dahl RH, Lamp CA, Molitoris BA. Apically and basolaterally internalized aminoglycosides colocalize in LLC-PK1 lysosomes and alter cell function. Am J Physiol 1994; 266:C52-7. [PMID: 8304430 DOI: 10.1152/ajpcell.1994.266.1.c52] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Aminoglycosides bind to apical and basolateral (BL) membranes of renal epithelial cells. However, little is known regarding differential uptake and intracellular processing after internalization across these distinct surface membrane domains. To examine these processes independently, LLC-PK1 cells were grown on porous filters, which allow selective access to both domains. Apical and BL membrane uptakes of gentamicin (0.5 mM), quantified using [3H]gentamicin, were linear from 2 to 24 h (r = 0.99). The 4-h apical gentamicin uptake was 667 +/- 59 pmol/mg protein, the BL 748 +/- 26 pmol/mg protein, and concurrent apical and BL uptake 1,389 +/- 22 pmol/mg protein. Aminoglycoside uptake, documented using indirect immunogold techniques, occurred via the apical and BL endocytic systems and colocalized with cationic ferritin. Aminoglycosides internalized via the apical (gentamicin) and BL (tobramycin) membrane converged at the lysosomal level. Gentamicin incorporated via either domain significantly decreased lysosomal N-acetylglucosaminidase below control values (P < 0.05). We conclude that, after binding, aminoglycosides are internalized equally across apical and BL membranes of LLC-PK1 cells via receptor-mediated endocytosis, colocalize within the lysosomal compartment, and alter cellular function similarly.
Collapse
Affiliation(s)
- D M Ford
- Department of Pediatrics, University of Colorado Health Sciences Center, Children's Hospital, Denver 80218
| | | | | | | |
Collapse
|
16
|
Abstract
In proximal tubular cells ischemia is known to result in the redistribution of apical and basolateral domain-specific lipids and proteins into the alternate surface membrane domain. Since tight junctions are required for the maintenance of surface membrane polarity, the effect of ischemia on tight junction functional integrity was investigated. In vivo microperfusion of early loops of proximal tubules with ruthenium red (0.2%) in glutaraldehyde (2%) was used to gain selective access to and outline the apical surface membrane. Under control situations ruthenium red penetrated less than 10% of the tight junctions. After 5, 15, and 30 min of ischemia, however, there was a successive stepwise increase in tight junction penetration by ruthenium red to 29, 50, and 62%, respectively. This was associated with the rapid duration-dependent redistribution of basolateral membrane domain-specific lipids and NaK-ATPase into the apical membrane domain. Taken together, these data indicate that during ischemia proximal tubule tight junctions open, which in turn leads to the lateral intramembranous diffusion of membrane components into the alternate surface membrane domain.
Collapse
Affiliation(s)
- B A Molitoris
- Department of Medicine, University of Colorado Medical Center, Denver
| | | | | |
Collapse
|
17
|
|
18
|
|
19
|
Dahl RH, Morrissey A, Puck TT, Morse ML. Carbohydrate energy sources for Chinese hamster cells in culture. Proc Soc Exp Biol Med 1976; 153:251-3. [PMID: 995956 DOI: 10.3181/00379727-153-39521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
20
|
Abstract
Histochemical tests, employing the Wachstein-Meisel medium, indicate that nucleoside triphosphatase activity is found predominantly in two areas of the frog skin epidermis: (1) in mitochondria, where activity is enhanced by dinitrophenol, Mg(2+) dependent, but inhibited by fixation; and (2) apparently associated with cell membranes of the middle and outer portions of the epidermis, where activity is inhibited by Mg(2+), unaffected by dinitrophenol, and only slightly reduced by fixation. Spectrophotometric analysis shows that Mg(2+) in the medium does not increase spontaneous hydrolysis of ATP, thus obviating the possible explanation that changes in substrate concentrations in the medium lead to alterations in the "staining" distributions. It is postulated that perhaps the two enzymes differ in their requirements for substrate-one requiring the polyphosphate to be in complexed form with Mg(2+), the other uncomplexed. Concentrations of Mg(2+) required to inhibit cell membrane nucleoside triphosphatase activity also inhibit the electrical potential difference and short-circuit current of the frog skin. Although these observations might be taken as presumptive evidence of the cell membrane enzyme as a component of the ion pump system, because of certain dissimilarities with respect to the biochemists' "transport ATPase" and for other reasons discussed in the paper, any definite conclusions in this regard are premature.
Collapse
|