A role for leukotrienes in cyclosporine nephrotoxicity
1区 · 医学
作者: Butterly, David W. ; Spurney, Robert F. ; Ruiz, Phillip ; Griffiths, Robert ; Albrightson, Christine ; Coffman, Thomas M.
Nephrotoxicity associated with cyclosporine A (CsA) administration is characterized by marked renal vasoconstriction, interstitial fibrosis, and arteriolar hypertrophy. While the molecular mechanisms of CsA toxicity are not well characterized, previous studies have demonstrated that altered arachidonic acid (AA) metabolism plays a role its pathogenesis. Using a rat renal transplant model, the purpose of this study was to examine the effects of CsA on the 5-lipoxygenase (5-LO) pathway of AA metabolism.
The PVG (RT1c) strain of rats underwent kidney transplantation, and recipients of nonrejecting kidney transplants were treated with either 50 mg/kg/day CsA or vehicle (N = 24). To determine the physiologic significance of increased leukotriene (LT) production, the peptidoleukotriene receptor antagonist SKF 106203 was administered to CsA-treated animals for six days.
CsA caused a substantial reduction in glomerular filtration rate (GFR) in the transplanted rats compared with the vehicle-treated controls (1.5 +/- 0.6 vs. 4.1 +/- 0.8 mL/min/kg, P < 0.05). The reduction in renal function was associated with enhanced urinary excretion of the peptidoleukotriene metabolites LTE4 (1431 +/- 207 vs. 953 +/- 125 pg/24 h, P < 0.05) and N-acetyl-LTE4 (4411 +/- 848 vs. 463 +/- 70 pg/24 h, P < 0.001). LT receptor blockade had a significant protective effect on renal transplant function in CsA-treated animals (GFR, 4.8 +/- 1.1 vs. 1.7 +/- 0.9 mL/min/kg, P < 0.05), such that CsA-treated animals that received SKF106203 maintained GFR at levels similar to controls that never received CsA (4.1 +/- 0.8 mL/min/kg). Peptidoleukotriene receptor blockade also prevented the histomorphological abnormalities caused by CsA, including tubular vacuolization.
These studies identify a critical role for LTs in the pathophysiology of CsA nephrotoxicity and suggest that LT antagonists may be useful in preventing CsA-associated kidney toxicity.
1994-01-15·Journal of Immunology2区 · 医学
Leukotrienes in renal transplant rejection in rats. Distinct roles for leukotriene B4 and peptidoleukotrienes in the pathogenesis of allograft injury
2区 · 医学
作者: Spurney, Robert F. ; Ibrahim, Sherif ; Butterly, David ; Klotman, Paul E. ; Sanfilippo, Fred ; Coffman, Thomas M.
To investigate the role of leukotrienes in renal allograft rejection, we studied the effects of specific leukotriene inhibitors in a rat kidney transplant model. The enhanced renal production of leukotrienes observed in allograft recipients was reduced in a dose-dependent manner by the specific 5-lipoxygenase inhibitor MK886. This suppression of leukotriene production caused a substantial improvement in renal function. Inhibition of 5-lipoxygenase also reduced the severity of vascular inflammation and endothelial injury in allografts, and profoundly inhibited expression of donor MHC class II Ag on kidney cells. Survival of renal allograft recipients was prolonged from 10 +/- 1 days in controls to 16 +/- 1 days in animals that received a 6-day course of MK886 (p < 0.05). To investigate the relative roles of LTB4 compared to peptidoleukotrienes in these processes, we treated a separate group of animals with the specific peptidoleukotriene receptor antagonist SKF106203. This agent inhibits the interaction of peptidoleukotrienes with their receptor(s) but does not affect the biologic actions of LTB4. In these studies, SKF106203 caused a modest improvement in renal allograft function that was of lesser magnitude than that seen with the 5-lipoxygenase inhibitor. SKF106203 also reduced vascular inflammation in allografts, but had no effect on expression of MHC class II Ag. We conclude that leukotrienes play a key role in the pathogenesis of renal allograft rejection. Furthermore, the detrimental effects of leukotrienes in rejection are mediated by distinct actions of LTB4 and peptidoleukotrienes.
1993-02-12·Journal of Chromatography
Column-switching high-performance liquid chromatographic method for the determination of SKF 106203 in human plasma after fluorescence derivatization with 9-anthryldiazomethane
作者: Miller-Stein, Cynthia ; Hwang, Bruce Y.-H. ; Rhodes, Gerald R. ; Boppana, Venkata K.
A sensitive and selective high-performance liquid chromatographic method was developed for the determination of SK&F 106203 3-(2-carboxyethylthio)-3-[2-(8-phenyloctyl)phenyl]propanoic acid, a potent peptidoleukotriene end organ receptor antagonist, in human plasma. The method involves isolation of SK&F 106203 and the internal standard (SK&F 104736) from plasma samples by liquid-liquid extraction prior to derivatization with 9-anthryldiazomethane. The derivatized samples were first subjected to a solid-phase extraction procedure prior to injection onto a short silica column, which is part of a chromatographic system equipped with an automated column-switching device. Column switching was used to heart-cut the chromatographic zone containing the peaks of interest from this first column and transfer it to an analytical silica column for further chromatographic separation. The peaks were quantified with an in-line fluorometer by measuring the fluorescence emission intensity at 415 nm after excitation at 365 nm. An on-column detection limit of 0.625 ng was achieved for SK&F 106203 by optimizing the derivatization and chromatography conditions. The limit of quantification for SK&F 106203, using 250 microliters of plasma, was 20 ng/ml. Linear response in SK&F 106203/internal standard peak-height ratios was observed for SK&F 106203 concentrations ranging from 10 to 5000 ng/ml of plasma. Precision and accuracy were within 5% across the calibration range. The assay was sufficiently sensitive, accurate, and precise to support pharmacokinetic studies in humans.