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Habas E, Al Adab A, Arryes M, Alfitori G, Farfar K, Habas AM, Akbar RA, Rayani A, Habas E, Elzouki A. Anemia and Hypoxia Impact on Chronic Kidney Disease Onset and Progression: Review and Updates. Cureus 2023; 15:e46737. [PMID: 38022248 PMCID: PMC10631488 DOI: 10.7759/cureus.46737] [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] [Accepted: 10/09/2023] [Indexed: 12/01/2023] Open
Abstract
Chronic kidney disease (CKD) is caused by hypoxia in the renal tissue, leading to inflammation and increased migration of pathogenic cells. Studies showed that leukocytes directly sense hypoxia and respond by initiating gene transcription, encoding the 2-integrin adhesion molecules. Moreover, other mechanisms participate in hypoxia, including anemia. CKD-associated anemia is common, which induces and worsens hypoxia, contributing to CKD progression. Anemia correction can slow CKD progression, but it should be cautiously approached. In this comprehensive review, the underlying pathophysiology mechanisms and the impact of renal tissue hypoxia and anemia in CKD onset and progression will be reviewed and discussed in detail. Searching for the latest updates in PubMed Central, Medline, PubMed database, Google Scholar, and Google search engines were conducted for original studies, including cross-sectional studies, cohort studies, clinical trials, and review articles using different keywords, phrases, and texts such as "CKD progression, anemia in CKD, CKD, anemia effect on CKD progression, anemia effect on CKD progression, and hypoxia and CKD progression". Kidney tissue hypoxia and anemia have an impact on CKD onset and progression. Hypoxia causes nephron cell death, enhancing fibrosis by increasing interstitium protein deposition, inflammatory cell activation, and apoptosis. Severe anemia correction improves life quality and may delay CKD progression. Detection and avoidance of the risk factors of hypoxia prevent recurrent acute kidney injury (AKI) and reduce the CKD rate. A better understanding of kidney hypoxia would prevent AKI and CKD and lead to new therapeutic strategies.
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Affiliation(s)
| | - Aisha Al Adab
- Internal Medicine, Hamad General Hospital, Doha, QAT
| | - Mehdi Arryes
- Internal Medicine, Hamad General Hospital, Doha, QAT
| | | | | | - Ala M Habas
- Internal Medicine, Tripoli University, Tripoli, LBY
| | - Raza A Akbar
- Internal Medicine, Hamad General Hospital, Doha, QAT
| | - Amnna Rayani
- Hemat-oncology Department, Pediatric Tripoli Hospital, Tripoli University, Tripoli, LBY
| | - Eshrak Habas
- Internal Medicine, Tripoli University, Tripoli, LBY
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Edwards A, Kurtcuoglu V. Renal blood flow and oxygenation. Pflugers Arch 2022; 474:759-770. [PMID: 35438336 PMCID: PMC9338895 DOI: 10.1007/s00424-022-02690-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 02/07/2023]
Abstract
Our kidneys receive about one-fifth of the cardiac output at rest and have a low oxygen extraction ratio, but may sustain, under some conditions, hypoxic injuries that might lead to chronic kidney disease. This is due to large regional variations in renal blood flow and oxygenation, which are the prerequisite for some and the consequence of other kidney functions. The concurrent operation of these functions is reliant on a multitude of neuro-hormonal signaling cascades and feedback loops that also include the regulation of renal blood flow and tissue oxygenation. Starting with open questions on regulatory processes and disease mechanisms, we review herein the literature on renal blood flow and oxygenation. We assess the current understanding of renal blood flow regulation, reasons for disparities in oxygen delivery and consumption, and the consequences of disbalance between O2 delivery, consumption, and removal. We further consider methods for measuring and computing blood velocity, flow rate, oxygen partial pressure, and related parameters and point out how limitations of these methods constitute important hurdles in this area of research. We conclude that to obtain an integrated understanding of the relation between renal function and renal blood flow and oxygenation, combined experimental and computational modeling studies will be needed.
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Affiliation(s)
- Aurelie Edwards
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA, 02215, USA
| | - Vartan Kurtcuoglu
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland. .,National Center of Competence in Research, Kidney.CH, University of Zurich, Zurich, Switzerland. .,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
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Kuo W, Le NA, Spingler B, Wenger RH, Kipar A, Hetzel U, Schulz G, Müller B, Kurtcuoglu V. Simultaneous Three-Dimensional Vascular and Tubular Imaging of Whole Mouse Kidneys With X-ray μCT. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:731-740. [PMID: 32627730 DOI: 10.1017/s1431927620001725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Concurrent three-dimensional imaging of the renal vascular and tubular systems on the whole-kidney scale with capillary level resolution is labor-intensive and technically difficult. Approaches based on vascular corrosion casting and X-ray micro computed tomography (μCT), for example, suffer from vascular filling artifacts and necessitate imaging with an additional modality to acquire tubules. In this work, we report on a new sample preparation, image acquisition, and quantification protocol for simultaneous vascular and tubular μCT imaging of whole, uncorroded mouse kidneys. The protocol consists of vascular perfusion with the water-soluble, aldehyde-fixable, polymeric X-ray contrast agent XlinCA, followed by laboratory-source μCT imaging and structural analysis using the freely available Fiji/ImageJ software. We achieved consistent filling of the entire capillary bed and staining of the tubules in the cortex and outer medulla. After imaging at isotropic voxel sizes of 3.3 and 4.4 μm, we segmented vascular and tubular systems and quantified luminal volumes, surface areas, diffusion distances, and vessel path lengths. This protocol permits the analysis of vascular and tubular parameters with higher reliability than vascular corrosion casting, less labor than serial sectioning and leaves tissue intact for subsequent histological examination with light and electron microscopy.
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Affiliation(s)
- Willy Kuo
- University of Zurich, Institute of Physiology, Winterthurerstrasse 190, 8057Zurich, Switzerland
- University of Zurich, National Centre of Competence in Research, Kidney. CH, Winterthurerstrasse 190, 8057Zurich, Switzerland
- University of Basel, Biomaterials Science Center, Department of Biomedical Engineering, Gewerbestrasse 14, 4123Allschwil, Switzerland
| | - Ngoc An Le
- University of Zurich, Department of Chemistry, Winterthurerstrasse 190, 8057Zurich, Switzerland
| | - Bernhard Spingler
- University of Zurich, Department of Chemistry, Winterthurerstrasse 190, 8057Zurich, Switzerland
| | - Roland H Wenger
- University of Zurich, Institute of Physiology, Winterthurerstrasse 190, 8057Zurich, Switzerland
- University of Zurich, National Centre of Competence in Research, Kidney. CH, Winterthurerstrasse 190, 8057Zurich, Switzerland
| | - Anja Kipar
- University of Zurich, Laboratory for Animal Model Pathology (LAMP), Institute of Veterinary Pathology, Vetsuisse Faculty, Winterthurerstrasse 268, 8057Zurich, Switzerland
| | - Udo Hetzel
- University of Zurich, Electron Microscopy Unit, Institute of Veterinary Pathology, Vetsuisse Faculty, Winterthurerstrasse 268, 8057Zurich, Switzerland
| | - Georg Schulz
- University of Basel, Biomaterials Science Center, Department of Biomedical Engineering, Gewerbestrasse 14, 4123Allschwil, Switzerland
| | - Bert Müller
- University of Basel, Biomaterials Science Center, Department of Biomedical Engineering, Gewerbestrasse 14, 4123Allschwil, Switzerland
| | - Vartan Kurtcuoglu
- University of Zurich, Institute of Physiology, Winterthurerstrasse 190, 8057Zurich, Switzerland
- University of Zurich, National Centre of Competence in Research, Kidney. CH, Winterthurerstrasse 190, 8057Zurich, Switzerland
- University of Zurich, Zurich Center for Integrative Human Physiology, 8057Zurich, Switzerland
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Gardiner BS, Smith DW, Lee C, Ngo JP, Evans RG. Renal oxygenation: From data to insight. Acta Physiol (Oxf) 2020; 228:e13450. [PMID: 32012449 DOI: 10.1111/apha.13450] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/14/2020] [Accepted: 01/30/2020] [Indexed: 12/14/2022]
Abstract
Computational models have made a major contribution to the field of physiology. As the complexity of our understanding of biological systems expands, the need for computational methods only increases. But collaboration between experimental physiologists and computational modellers (ie theoretical physiologists) is not easy. One of the major challenges is to break down the barriers created by differences in vocabulary and approach between the two disciplines. In this review, we have two major aims. Firstly, we wish to contribute to the effort to break down these barriers and so encourage more interdisciplinary collaboration. So, we begin with a "primer" on the ways in which computational models can help us understand physiology and pathophysiology. Second, we aim to provide an update of recent efforts in one specific area of physiology, renal oxygenation. This work is shedding new light on the causes and consequences of renal hypoxia. But as importantly, computational modelling is providing direction for experimental physiologists working in the field of renal oxygenation by: (a) generating new hypotheses that can be tested in experimental studies, (b) allowing experiments that are technically unfeasible to be simulated in silico, or variables that cannot be measured experimentally to be estimated, and (c) providing a means by which the quality of experimental data can be assessed. Critically, based on our experience, we strongly believe that experimental and theoretical physiology should not be seen as separate exercises. Rather, they should be integrated to permit an iterative process between modelling and experimentation.
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Affiliation(s)
- Bruce S. Gardiner
- College of Science Health, Engineering and Education Murdoch University Perth Australia
- Faculty of Engineering and Mathematical Sciences The University of Western Australia Perth Australia
| | - David W. Smith
- Faculty of Engineering and Mathematical Sciences The University of Western Australia Perth Australia
| | - Chang‐Joon Lee
- College of Science Health, Engineering and Education Murdoch University Perth Australia
- Faculty of Engineering and Mathematical Sciences The University of Western Australia Perth Australia
| | - Jennifer P. Ngo
- Cardiovascular Disease Program Biomedicine Discovery Institute and Department of Physiology Monash University Melbourne Australia
- Department of Cardiac Physiology National Cerebral and Cardiovascular Research Center Osaka Japan
| | - Roger G. Evans
- Cardiovascular Disease Program Biomedicine Discovery Institute and Department of Physiology Monash University Melbourne Australia
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Evans RG, Smith DW, Lee C, Ngo JP, Gardiner BS. What Makes the Kidney Susceptible to Hypoxia? Anat Rec (Hoboken) 2019; 303:2544-2552. [DOI: 10.1002/ar.24260] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/24/2019] [Accepted: 05/13/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Roger G. Evans
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology Monash University Melbourne Victoria Australia
| | - David W. Smith
- Faculty of Engineering and Mathematical Sciences The University of Western Australia Perth Western Australia Australia
| | - Chang‐Joon Lee
- Faculty of Engineering and Mathematical Sciences The University of Western Australia Perth Western Australia Australia
- College of Science, Health, Engineering and Education Murdoch University Perth Western Australia Australia
| | - Jennifer P. Ngo
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology Monash University Melbourne Victoria Australia
| | - Bruce S. Gardiner
- Faculty of Engineering and Mathematical Sciences The University of Western Australia Perth Western Australia Australia
- College of Science, Health, Engineering and Education Murdoch University Perth Western Australia Australia
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Ngo JP, Le B, Khan Z, Kett MM, Gardiner BS, Smith DW, Melhem MM, Maksimenko A, Pearson JT, Evans RG. Micro-computed tomographic analysis of the radial geometry of intrarenal artery-vein pairs in rats and rabbits: Comparison with light microscopy. Clin Exp Pharmacol Physiol 2017; 44:1241-1253. [PMID: 28795785 DOI: 10.1111/1440-1681.12842] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 08/01/2017] [Accepted: 08/01/2017] [Indexed: 02/06/2023]
Abstract
We assessed the utility of synchrotron-radiation micro-computed tomography (micro-CT) for quantification of the radial geometry of the renal cortical vasculature. The kidneys of nine rats and six rabbits were perfusion fixed and the renal circulation filled with Microfil. In order to assess shrinkage of Microfil, rat kidneys were imaged at the Australian Synchrotron immediately upon tissue preparation and then post fixed in paraformaldehyde and reimaged 24 hours later. The Microfil shrank only 2-5% over the 24 hour period. All subsequent micro-CT imaging was completed within 24 hours of sample preparation. After micro-CT imaging, the kidneys were processed for histological analysis. In both rat and rabbit kidneys, vascular structures identified in histological sections could be identified in two-dimensional (2D) micro-CT images from the original kidney. Vascular morphology was similar in the two sets of images. Radial geometry quantified by manual analysis of 2D images from micro-CT was consistent with corresponding data generated by light microscopy. However, due to limited spatial resolution when imaging a whole organ using contrast-enhanced micro-CT, only arteries ≥100 and ≥60 μm in diameter, for the rat and rabbit respectively, could be assessed. We conclude that it is feasible and valid to use micro-CT to quantify vascular geometry of the renal cortical circulation in both the rat and rabbit. However, a combination of light microscopic and micro-CT approaches are required to evaluate the spatial relationships between intrarenal arteries and veins over an extensive range of vessel size.
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Affiliation(s)
- Jennifer P Ngo
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
| | - Bianca Le
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
| | - Zohaib Khan
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, WA, Australia.,School of Information Technology and Mathematical Sciences, University of South Australia, Adelaide, SA, Australia
| | - Michelle M Kett
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
| | - Bruce S Gardiner
- School of Engineering and Information Technology, Murdoch University, Perth, WA, Australia
| | - David W Smith
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, WA, Australia
| | - Mayer M Melhem
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
| | - Anton Maksimenko
- Imaging and Medical Beamline, Australian Synchrotron, Clayton, Vic., Australia
| | - James T Pearson
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia.,Monash Biomedical Imaging Facility, Monash University, Melbourne, Vic., Australia.,Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Roger G Evans
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Vic., Australia
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Lee CJ, Ngo JP, Kar S, Gardiner BS, Evans RG, Smith DW. A pseudo-three-dimensional model for quantification of oxygen diffusion from preglomerular arteries to renal tissue and renal venous blood. Am J Physiol Renal Physiol 2017; 313:F237-F253. [DOI: 10.1152/ajprenal.00659.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/24/2017] [Accepted: 04/02/2017] [Indexed: 01/13/2023] Open
Abstract
To assess the physiological significance of arterial-to-venous (AV) oxygen shunting, we generated a new pseudo-three-dimensional computational model of oxygen diffusion from intrarenal arteries to cortical tissue and veins. The model combines the 11 branching levels (known as “Strahler” orders) of the preglomerular renal vasculature in the rat, with an analysis of an extensive data set obtained using light microscopy to estimate oxygen mass transfer coefficients for each Strahler order. Furthermore, the AV shunting model is now set within a global oxygen transport model that includes transport from arteries, glomeruli, peritubular capillaries, and veins to tissue. While a number of lines of evidence suggest AV shunting is significant, most importantly, our AV oxygen shunting model predicts AV shunting is small under normal physiological conditions (~0.9% of total renal oxygen delivery; range 0.4–1.4%), but increases during renal ischemia, glomerular hyperfiltration (~2.1% of total renal oxygen delivery; range 0.84–3.36%), and some cardiovascular disease states (~3.0% of total renal oxygen delivery; range 1.2–4.8%). Under normal physiological conditions, blood Po2 is predicted to fall by ~16 mmHg from the root of the renal artery to glomerular entry, with AV oxygen shunting contributing ~40% and oxygen diffusion from arteries to tissue contributing ~60% of this decline. Arterial Po2 is predicted to fall most rapidly from Strahler order 4, under normal physiological conditions. We conclude that AV oxygen shunting normally has only a small impact on renal oxygenation, but may exacerbate renal hypoxia during renal ischemia, hyperfiltration, and some cardiovascular disease states.
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Affiliation(s)
- Chang-Joon Lee
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Jennifer P. Ngo
- Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Sydney, Australia; and
| | - Saptarshi Kar
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Bruce S. Gardiner
- School of Engineering and Information Technology, Murdoch University, Perth, Western Australia, Australia
| | - Roger G. Evans
- Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Sydney, Australia; and
| | - David W. Smith
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
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