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Pathogenetic mechanisms of nephrotoxicity: insights into cyclosporine nephrotoxicity
Abstract:
Drugs may produce acute renal failure by prerenal, intrarenal and obstructive (postrenal) mechanisms. Prerenal processes usually develop from an imbalance of the normal counterbalancing vasoconstrictor and vasodilatory substances regulating RBF, resulting in a predominant vasoconstrictive state. Intrarenal processes develop from toxic renal tubule epithelial cell injury. The pathogenesis of renal cell injury is a complex interplay among derangements in subcellular membrane functions and mediators of injurious processes. Plasma and subcellular membrane injury and resulting membrane dysfunction appear most important. Cyclosporine has the ability to interact with renal tubular cell membranes in a relatively specific manner and at low concentrations. Despite this interaction, the acute declines in renal excretory function produced by cyclosporine is due predominantly to functional declines in RBF rather than structural derangements in renal tubular cell integrity. Cyclosporine-induced acute renal failure, thus, appears to be due predominantly to prerenal, rather than intrarenal, processes in the experimental animal. Cyclosporine does, however, possess a limited toxic potential to injure renal cortical cells, so that a chronic tubulointerstitial nephropathy may develop with long-term use of this immunosuppressive agent.
Insights
Cyclosporine causes acute renal failure primarily through prerenal mechanisms, affecting renal blood flow (RBF) rather than direct kidney cell damage. Long-term use may lead to chronic kidney injury.
Area of Science:
- Nephrology
- Pharmacology
- Toxicology
Background:
- Drugs can induce acute renal failure via prerenal (hemodynamic), intrarenal (cellular injury), or obstructive pathways.
- Prerenal failure stems from an imbalance in renal blood flow (RBF) regulation, favoring vasoconstriction.
- Intrarenal failure involves direct toxic injury to renal tubule epithelial cells.
Purpose of the Study:
- To investigate the mechanisms of cyclosporine-induced acute renal failure.
- To differentiate between prerenal and intrarenal contributions to cyclosporine nephrotoxicity.
Main Methods:
- The study focuses on the pathogenetic mechanisms of drug-induced acute renal failure.
- Analysis of cyclosporine's interaction with renal tubular cell membranes and its effects on RBF and renal cell integrity.
Main Results:
- Cyclosporine interacts with renal tubular cell membranes, but acute functional decline is mainly due to reduced RBF (prerenal effect).
- Structural damage to renal tubular cells (intrarenal effect) is less significant in acute cyclosporine toxicity.
- Experimental animals show cyclosporine-induced acute renal failure is predominantly prerenal.
Conclusions:
- Acute cyclosporine nephrotoxicity is primarily mediated by prerenal mechanisms affecting renal blood flow.
- While acute effects are mainly functional, chronic cyclosporine administration may lead to tubulointerstitial nephropathy due to limited direct cellular toxicity.