Previous investigations of acute renal failure have described impairment in regulation of vasomotor tone within the renal circulation, ranging from persistent vasoconstriction to abnormalities in the vascular response to a number of vasodilators and vasoconstrictors. In large part these observations remain without further explanatory mechanisms. Of interest in this regard is the explosion of new information indicating that endothelial cells elaborate powerful vasodilating (endothelium-derived relaxation factor, EDRF) and vasoconstricting (endothelin) substances which can regulate local vascular tone, regional blood flow and, in the kidney, the potential to modulate the process of glomerular filtration. Preliminary data collected thus far, support important roles for both EDRF and endothelin in modulating the renal circulation and GFR. The studies will be performed in Munich-Wistar rats with renal injury secondary to ischemia/reperfusion, exposure to endotoxin and activated polymorphonuclear leukocytes. The proposed projects include a newly developed technique which allows experimental manipulations of portions of a kidney: infusion of a branch of the main renal artery (endothelin, endothelin antibody, endotoxin etc). Micropuncture techniques can compare hemodynamics and morphological techniques can compare the structural changes in manipulated and non manipulated glomeruli/vasculature within that kidney.
The specific aims i nclude: 1) Physiologic assessment of the contribution of endothelial cells to abnormal renal hemodynamics in several forms of acute renal failure and the role of reactive oxygen species in these phenomenon. 2) Morphological assessment within the renal microcirculation to exogenous/endogenous endothelin. 3) Assessment of modulation by endothelium-derived substances by measuring biochemical markers in normal and injured kidneys, glomeruli and mesangial cells. 4) Assessment of endothelin in plasma and other physiologic fluids in conditions having injured endothelial cells. 5) Characterization of glomerular endothelin receptors in injured kidneys.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK042159-02
Application #
3243200
Study Section
Cardiovascular and Renal Study Section (CVB)
Project Start
1990-07-01
Project End
1993-06-30
Budget Start
1991-07-01
Budget End
1992-06-30
Support Year
2
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Hunley, T E; Kon, V (2001) Update on endothelins - biology and clinical implications. Pediatr Nephrol 16:752-62
Hunley, T E; Tamura, M; Stoneking, B J et al. (2000) The angiotensin type II receptor tonically inhibits angiotensin- converting enzyme in AT2 null mutant mice. Kidney Int 57:570-7
Hohenfellner, K; Hunley, T E; Yerkes, E et al. (1999) Angiotensin II, type 2 receptor in the development of vesico-ureteric reflux. BJU Int 83:318-22
Hohenfellner, K; Hunley, T E; Schloemer, C et al. (1999) Angiotensin type 2 receptor is important in the normal development of the ureter. Pediatr Nephrol 13:187-91
Gainer, J V; Hunley, T E; Kon, V et al. (1997) Angiotensin II type I receptor polymorphism in African Americans lower frequency of the C1166 variant. Biochem Mol Biol Int 43:227-31
Hunley, T E; Julian, B A; Phillips 3rd, J A et al. (1996) Angiotensin converting enzyme gene polymorphism: potential silencer motif and impact on progression in IgA nephropathy. Kidney Int 49:571-7
Fogo, A; Kon, V (1996) Treatment of hypertension. Semin Nephrol 16:555-66
Kon, V; Hunley, T E; Fogo, A (1995) Combined antagonism of endothelin A/B receptors links endothelin to vasoconstriction whereas angiotensin II effects fibrosis. Studies in chronic cyclosporine nephrotoxicity in rats. Transplantation 60:89-95
Hunley, T E; Iwasaki, S; Homma, T et al. (1995) Nitric oxide and endothelin in pathophysiological settings. Pediatr Nephrol 9:235-44
Hunley, T E; Fogo, A; Iwasaki, S et al. (1995) Endothelin A receptor mediates functional but not structural damage in chronic cyclosporine nephrotoxicity. J Am Soc Nephrol 5:1718-23

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