Journal of the American Society of Nephrology : JASN
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J. Am. Soc. Nephrol. · Feb 2000
Ischemic acute renal failure induces differential expression of small heat shock proteins.
AlphaB-crystallin and heat shock protein (hsp) 25 are structurally and functionally related small stress proteins induced by a variety of insults, including heat and ischemia. Cytoprotection by these two hsp is thought to result from molecular chaperoning and/or cytoskeletal stabilization. Because renal ischemia is characterized by disruption of the renal tubular cell actin cytoskeleton, this study was conducted to determine the localization and quantify the expression and phosphorylation of both hsp in renal cortex, isolated glomeruli, outer medulla, and inner medulla of rats after bilateral renal ischemia. ⋯ In sham-operated kidneys, hsp25 localized to glomeruli, vessels, and collecting ducts, with alphaB-crystallin primarily in medullary thin limbs and collecting ducts. After ischemia, hsp25 accumulated in proximal tubules in cortex and outer medulla, while alphaB-crystallin labeling became nonhomogeneous in outer medulla, and increased in Bowman's capsule. It is concluded that: (1) There is striking differential expression of hsp25 and alphaB-crystallin in various renal compartments; and (2) Renal ischemia results in differential accumulation of hsp25 and alphaB-crystallin, with hsp25 part of a generalized stress response in renal proximal tubular cells, which may play a role in recovery from ischemia-induced actin filament disruption.
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J. Am. Soc. Nephrol. · Feb 2000
Comparative StudyRenal transplantation from non-heart beating donors: a promising alternative to enlarge the donor pool.
The aim of this study was to compare the survival and midterm function of kidneys from non-heart beating donors (NHBD) with those of kidneys from heart beating donors (HBD). From 1989 to 1998, 144 kidneys were procured from NHBD at the Hospital Clínico San Carlos in Madrid, of which 95 were transplanted. The kidney grafts were maintained from the moment of the diagnosis of cardiac arrest until the time of procurement by cardiopulmonary bypass. ⋯ Fifty-four of these kidneys were transplanted and all showed primary function. When a strict protocol is adhered to, the outcome of renal transplant from NHBD compares well with that from HBD. It is believed that the high number of organs obtained from subjects undergoing irreversible cardiac arrest on the street might encourage the adoption of new criteria for the management of this type of pathology with the ultimate goal of kidney donation.
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J. Am. Soc. Nephrol. · Feb 2000
Effects of tetrahydrobiopterin on endothelial dysfunction in rats with ischemic acute renal failure.
The role of nitric oxide (NO) in ischemic renal injury is still controversial. NO release was measured in rat kidneys subjected to ischemia and reperfusion to determine whether (6R)-5,6,7,8-tetrahydro-L-biopterin (BH4), a cofactor of NO synthase (NOS), reduces ischemic injury. Twenty-four hours after bilateral renal arterial clamp for 45 min, acetylcholine-induced vasorelaxation and NO release were reduced and renal excretory function was impaired in Wistar rats. ⋯ However, it was restored by BH4 (control 5.0 +/- 0.9, ischemia 2.2 +/- 0.4, ischemia + BH4 4.3 +/- 1.2 pmol/min per mg protein). Immunoblot after low-temperature sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the dimeric form of endothelial NOS decreased in the ischemic kidney and that it was restored by BH4. These results suggest that the decreased activity of endothelium-derived NO may worsen the ischemic tissue injury, in which depletion of BH4 may be involved.