Rho kinase inhibition protects kidneys from diabetic nephropathy without reducing blood pressure.
Rho-associated kinases (ROCK) are activated in the kidney as well as in cultured cells of diabetic models and have been implicated in renal pathophysiology. To explore whether inhibition of ROCK is protective, we studied its role in a model of accelerated diabetic nephropathy where uninephrectomized rats were made diabetic by streptozotocin. After establishing diabetes, rats were treated with the ROCK inhibitor fasudil continuously or for the final 6 weeks of an 18-week experimental period. The results were compared to similar rats given losartan, an established treatment of clinical and experimental diabetic nephropathy, or a combination of both agents. Vehicle-treated diabetic and non-diabetic uninephrectomized rats served as controls. Diabetes resulted in a rapid development of albuminuria, higher glomerulosclerosis and interstitial fibrosis scores, lower glomerular filtration rates, and increased expression of several molecular markers of diabetic nephropathy. Eighteen weeks of fasudil treatment reduced renal ROCK activity, and ameliorated diabetes-induced structural changes in the kidney and expression of the molecular markers in association with a modest anti-proteinuric effect but no change in blood pressure. Late intervention with fasudil reduced glomerulosclerosis, but did not influence proteinuria. Most effects of fasudil were comparable to those of losartan, although losartan lowered blood pressure and further lowered proteinuria. The combination of both treatments was no different than losartan alone. Thus, ROCK inhibition protected the kidney from diabetic nephropathy even though it did not reduce the blood pressure.
Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon 97239-2940, USA. komersr@ohsu.edu
Radko
R
Komers
Terry T
TT
Oyama
Douglas R
DR
Beard
Chris
C
Tikellis
Bei
B
Xu
Daniel F
DF
Lotspeich
Sharon
S
Anderson
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000201:enzymology; D003928:Diabetic Nephropathies / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D007668:Kidney / Q000187:drug effects* / Q000201:enzymology* / Q000473:pathology; D019808:Losartan / Q000494:pharmacology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009392:Nephrectomy; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors*
D047228:Angiotensin II Type 1 Receptor Blockers; D008565:Membrane Proteins; D047428:Protein Kinase Inhibitors; D042461:Vascular Endothelial Growth Factor A; C113267:nephrin; C467498:vascular endothelial growth factor A, rat; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D054460:rho-Associated Kinases; D019808:Losartan; C049347:fasudil