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Postepy Higieny I Medycyny... Jul 2015Interstitium - the renal tubulointerstitial compartment - is located between the renal tubule basement membrane and microcirculation vessels. Interstitial fibroblasts... (Review)
Review
Interstitium - the renal tubulointerstitial compartment - is located between the renal tubule basement membrane and microcirculation vessels. Interstitial fibroblasts produce the extracellular matrix and constitute the structure's cellular skeleton, regulating spatial relationships between its components (microenvironment). The tubular epithelium and endothelium cooperate within an integrated microenvironment. Structural or functional impairment of the extracellular matrix, microcirculation vessels or tubular epithelium results in disturbances of tubulointerstitial compartment components. In the course of glomerular kidney diseases, the intrarenal RAA system becomes activated and inflammatory mediators are released. Interstitial inflammation and microcirculatory disorders develop, inducing adverse consequences, manifested mainly through the process of hypoxia and inflammation. Inflammation-induced increase in interleukin-1 (TNF-α) expression leads to increased concentrations of VEGF, ICAM-1, angiotensin II, IL-6 and IL-8. Cytokines activate fibroblasts, myofibroblasts and endothelial cells. Fibrosis is also triggered by HIF-1alpha pathway activation, resulting in vascular growth and fibroblast proliferation. This reaction likewise occurs through activation of NF-ĸβ, EPO, GLUT-1, IGF-1 and INOS. Interstitial fibrosis is one of the factors determining the clinical course of kidney diseases. Apart from inducing fibrosis, microcirculatory disorders lead to the progression of hypoxia. Angiogenesis is a part of the repair process accompanying fibrosis. Its determinant is the normal function and structure of endothelial cells manifested by their ability to migrate and proliferate in response to, inter alia, angiopoietins, VEGF and nitric oxide synthase. Administering a three-drug RAAS-inhibiting therapy to patients with chronic glomerulopathies improves tubular function, measured by the decrease in excretion of NAG and propeptide of type III procollagen fibres, and contributes to the improvement in microcirculation functioning.
Topics: Cell Proliferation; Disease Progression; Endothelial Cells; Fibroblasts; Humans; Renal Insufficiency, Chronic
PubMed: 26206996
DOI: 10.5604/17322693.1162570 -
Advances in Physiology Education Sep 2023An Australia-wide consensus was reached on seven core concepts of physiology, one of which was "structure and function" with the descriptor "Structure and function are...
An Australia-wide consensus was reached on seven core concepts of physiology, one of which was "structure and function" with the descriptor "Structure and function are intrinsically related to all levels of the organism. In all physiological systems, the structure from a microscopic level to an organ level dictates its function." As a framework for the structure and function core concept, the renal system was unpacked by a team of 5 Australian Physiology educators from different universities with extensive teaching experience into hierarchical levels, with 5 themes and 25 subthemes up to 3 levels deep. Within , the structures that comprise the renal system were unpacked. Within , the physiological processes within the nephron such as filtration, reabsorption, and secretion were unpacked. Within , the processes involved in micturition were unpacked. In , the structures and processes involved in regulating renal blood flow and glomerular filtration were unpacked; and within , the role of the kidney in red blood cell production was unpacked. Twenty-one academics rated the difficulty and importance of each theme/subtheme, and results were analyzed using a one-way ANOVA. All identified themes were validated as "essential" to "important"/"moderately important" and rated between "difficult" to "not difficult." A similar framework consisting of structure, physiological processes, physical processes, and regulation can be used to unpack other body systems. Unpacking of the body systems will provide a list of what students should be taught in curricula across Australian universities and inform assessment and learning activities. This is the first attempt to unpack and validate the "structure and function" core concept in physiology with all Australian educators. We unpacked the renal system into themes with hierarchical levels, which were validated by an experienced team of Australian physiology educators. Our unpacking of the "structure and function" core concept provides a specific framework for educators to apply this important concept in physiology education.
Topics: Humans; Australia; Curriculum; Kidney; Learning; Physiology; Universities
PubMed: 37199738
DOI: 10.1152/advan.00150.2022 -
American Journal of Nephrology 2018
Topics: Atrial Fibrillation; Cardio-Renal Syndrome; Cause of Death; Electrophysiology; Humans; Hypertension; Renal Insufficiency, Chronic
PubMed: 30032155
DOI: 10.1159/000491024 -
Liver Transplantation : Official... Jun 2016An alternative to liver transplantation for patients with liver failure remains an unmet need. In acute liver failure, the ideal extracorporeal liver support device... (Review)
Review
An alternative to liver transplantation for patients with liver failure remains an unmet need. In acute liver failure, the ideal extracorporeal liver support device (ELSD) would replace the functions of the failing liver in order to permit spontaneous recovery, given the incredible regenerative potential of the liver, negating the need for transplantation. In acute-on-chronic liver failure, an ELSD would ideally support hepatic function until a recovery to liver function before acute decompensation or until liver transplantation. In decompensated cirrhosis, an ELSD could again be used to support hepatic function until transplant. In addition, ELSDs may have the potential to treat the multiorgan failure that accompanies liver failure including hepatic encephalopathy, renal failure, and immune dysfunction or indeed potential to promote liver regeneration. Creation of an extracorporeal bioartificial liver able to completely replace liver function remains an unmet need. This review will describe a number of technologies suitable for clinical trials in humans, which have resulted from decades of engineering and biological research to develop a bioreactor able to adequately sustain functional hepatocytes. In addition, this review will describe artificial liver support devices that are primarily designed to replace the detoxifying functions of the liver and will consider the current data available or studies required to support their use in liver failure patients on the transplant waiting list. Liver Transplantation 22 839-848 2016 AASLD.
Topics: Bioreactors; Clinical Trials as Topic; Dialysis; Hepatocytes; Humans; Liver; Liver Failure; Liver Regeneration; Liver Transplantation; Liver, Artificial; Plasma Exchange; Renal Insufficiency; Waiting Lists
PubMed: 26785141
DOI: 10.1002/lt.24396 -
Circulation Research Apr 2023The endothelium is considered to be the gatekeeper of the vessel wall, maintaining and regulating vascular integrity. In patients with chronic kidney disease, protective... (Review)
Review
The endothelium is considered to be the gatekeeper of the vessel wall, maintaining and regulating vascular integrity. In patients with chronic kidney disease, protective endothelial cell functions are impaired due to the proinflammatory, prothrombotic and uremic environment caused by the decline in kidney function, adding to the increase in cardiovascular complications in this vulnerable patient population. In this review, we discuss endothelial cell functioning in healthy conditions and the contribution of endothelial cell dysfunction to cardiovascular disease. Further, we summarize the phenotypic changes of the endothelium in chronic kidney disease patients and the relation of endothelial cell dysfunction to cardiovascular risk in chronic kidney disease. We also review the mechanisms that underlie endothelial changes in chronic kidney disease and consider potential pharmacological interventions that can ameliorate endothelial health.
Topics: Humans; Cardiovascular Diseases; Endothelium, Vascular; Risk Factors; Renal Insufficiency, Chronic; Vascular Diseases; Endothelial Cells; Heart Disease Risk Factors
PubMed: 37053275
DOI: 10.1161/CIRCRESAHA.123.321752 -
Cellular Physiology and Biochemistry :... Oct 2022The functioning of complex organisms requires a constant and delicate balance of processes both between and within cells, tissues, and organ systems. There is growing... (Review)
Review
The functioning of complex organisms requires a constant and delicate balance of processes both between and within cells, tissues, and organ systems. There is growing appreciation for the role of signalling crosstalk connecting different organ systems of the body, even from tissues traditionally classified as "inert" in terms of their capacity to produce chemical signals that can act on other organ systems. Many of these secreted molecules have been shown to contribute to, or exacerbate, a variety of functions and diseases in other organ systems, even if the two organs are not functionally linked. For example, there is a strong association with skeletal muscle atrophy and dysfunction in patients with chronic kidney disease (CKD). Identification of molecules produced and secreted by skeletal muscle has existed for some time, and there is emerging evidence that skeletal muscle may directly affect kidney function. Conversely, factors produced and secreted by the kidneys in various models of CKD have been shown to contribute to reduced muscle functionality. This review will focus on crosstalk in both directions between skeletal muscle and the kidneys. The emphasis will be on direct interaction between these organs using examples of secreted factors that are produced by the muscle or kidneys (including activin A, myostatin, microRNA's, irisin and mitsugumin 53), often under pathophysiological conditions. Our understanding of how the kidneys and skeletal muscle interact with each other is key to elucidating the pathophysiology processes that drive health and disease.
Topics: Animals; Humans; Myostatin; Fibronectins; Disease Models, Animal; Muscle, Skeletal; Renal Insufficiency, Chronic; Kidney; MicroRNAs
PubMed: 36285606
DOI: 10.33594/000000578 -
Philosophical Transactions of the Royal... Dec 1997In youth, most physiological functions have generous spare capacity. Even in health, however, increasing age is characterized by progressive erosion of these 'safety... (Review)
Review
In youth, most physiological functions have generous spare capacity. Even in health, however, increasing age is characterized by progressive erosion of these 'safety margins'. Examples include the decline of bone mass (towards a threshold for likelihood of fracture), of glomerular filtration rate (towards a threshold for susceptibility to clinical renal failure), of renal tubular function (towards a threshold for clinically important susceptibility to dehydration), of hepatic function (towards a threshold for accumulation following conventional 'young adult' doses of common medications), or of lower limb explosive power (towards thresholds for impaired functional mobility). Increasing age is also characterized by a rising prevalence of chronic pathologies, complicating attempts to determine the rate or the mechanism of the age-related decline in a physiological function. Nevertheless, it is clear that in many organs the loss of function is largely attributable to the loss of functioning cells, even in the absence of overt disease. This apparently fundamental aspect of ageing remains poorly understood.
Topics: Adult; Aged; Aged, 80 and over; Aging; Bone Diseases; Cachexia; Exercise; Female; Hand Strength; Health Status; Humans; Kidney Diseases; Liver Diseases; Male; Middle Aged; Muscle Development; Muscle, Skeletal; Muscular Diseases
PubMed: 9460068
DOI: 10.1098/rstb.1997.0169 -
Biochimica Et Biophysica Acta Apr 2009The epithelial cell tight junction has several functions including the control of paracellular transport between epithelial cells. Renal paracellular transport has been... (Review)
Review
The epithelial cell tight junction has several functions including the control of paracellular transport between epithelial cells. Renal paracellular transport has been long recognized to exhibit unique characteristics within different segments of the nephron, functions as an important component of normal renal physiology and has been speculated to contribute to renal related pathology if functioning abnormally. The discovery of a large family of tight junction associated 4-transmembrane spanning domain proteins named claudins has advanced our understanding on how the paracellular permeability properties of tight junctions are determined. In the kidney, claudins are expressed in a nephron-specific pattern and are major determinants of the paracellular permeability of tight junctions in different nephron segments. The combination of nephron segment claudin expression patterns, inherited renal diseases, and renal epithelial cell culture models is providing important clues about how tight junction claudin molecules function in different segments of the nephron under normal and pathological conditions. This review discusses early observations of renal tubule paracellular transport and more recent information on the discovery of the claudin family of tight junction associated membrane proteins and how they relate to normal renal function as well as diseases of the human kidney.
Topics: Acid-Base Equilibrium; Animals; Claudin-1; Gitelman Syndrome; Homeostasis; Humans; Intracellular Signaling Peptides and Proteins; Kidney; Kidney Diseases; Membrane Proteins; Minor Histocompatibility Antigens; Protein Serine-Threonine Kinases; Tight Junctions; WNK Lysine-Deficient Protein Kinase 1
PubMed: 18675779
DOI: 10.1016/j.bbamem.2008.07.004 -
American Journal of Physiology. Renal... Jun 2017
Topics: Awards and Prizes; Biomedical Research; History, 20th Century; History, 21st Century; Humans; Kidney; Nephrology; Physiology; Potassium; Water-Electrolyte Balance
PubMed: 28381461
DOI: 10.1152/ajprenal.00171.2017 -
Canadian Medical Association Journal Oct 1964The possible relationship between the renal mechanism of volume control and blood pressure regulation is discussed. Expansion of the extracellular fluid (ECF) and plasma... (Review)
Review
The possible relationship between the renal mechanism of volume control and blood pressure regulation is discussed. Expansion of the extracellular fluid (ECF) and plasma volumes was demonstrated following renal artery constriction in the rat; after about one month ECF volume returned to normal although hypertension persisted. Measurements of cardiac output in the unanesthetized rat by an implanted electromagnetic flowmeter showed an initial rise in cardiac output after renal artery constriction, returning to normal in 10 to 15 days. A homeostatic hypothesis for the production of renal hypertension is put forward in which changes in ECF volume, capacity vessel tone and myocardial contractility participate in the development of hypertension by elevating cardiac output. Autoregulation of peripheral flow then occurs and the consequent restoration of blood pressure at a renal pressure receptor results in return to normal of cardiac output by negative feedback. Thus in chronic hypertension the high peripheral resistance is maintained by autoregulation.
Topics: Aldosterone; Angiotensins; Blood Pressure; Cardiac Output; Hypertension; Hypertension, Renal; Kidney; Physiology; Rats; Renal Artery Obstruction; Renin; Research; Sodium; Vascular Resistance; Vasomotor System; Water-Electrolyte Balance
PubMed: 14217261
DOI: No ID Found