Angiotensin Receptor Blockade Improves Renal Blood Flow in Diabetics

Chronic angiotensin II receptor blockade with olmesartan improves renal vascular perfusion despite significant blood pressure reductions in patients with type 2 diabetes.

Dr. Danilo Fliser from Medical School Hannover stated that, "Angiotensin II subtype 1 receptor antagonists (AT1-RA) not only lower blood pressure, but at the same time lower intraglomerular pressure and increase renal perfusion." "Thus, their use offers a complete prevention of hemodynamically mediated damage to the diabetic kidney."

Dr. Fliser and colleagues examined the effect of 12 weeks of treatment with the AT1-RA olmesartan on renal hemodynamics in 35 patients with type 2 diabetes.

Blood pressure fell significantly with olmesartan treatment, the authors report, but did not change significantly in patients that received placebo.

Olmesartan treatment was associated with a significant increase in effective renal plasma flow and decreases in filtration fraction and renal vascular resistance, but glomerular filtration rate did not change with AT1-RA blockade. In contrast, patients that received placebo experienced a significant increase in filtration fraction and a nonsignificant increase in renal vascular resistance.
Reductions in isoprostane generation in the patients treated with olmesartan suggest that chronic AT1-RA blockade may prevent renal vascular damage not only by direct hemodynamic effects but also by reducing inflammation and/or reactive oxygen species generation, the investigators explain.

"Our results document that the favorable renal hemodynamic action of AT1-RA observed in acute experiments in individuals with type 2 diabetes persists even after prolonged AT1-receptor blockade," the authors conclude. "This effect may contribute to the renoprotective effect of AT1-RA documented in large prospective trials on prevention of progression of diabetic nephropathy."

Dr. Fliser added that "our findings support the routine use of AT1-RA, at least in diabetic patients with hypertension and/or presence of renal involvement."
J Am Soc Nephrol 2005

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FACT:
In patients with type 2 diabetes, treatment with lipid-lowering agents reduces cardiovascular risk. "Most patients, including those whose baseline LDL cholesterol levels are below 115 mg/dL, and possibly below 100 mg/dL, benefit from statins. Moderate doses of these drugs suffice in most patients with diabetes."
Ann Intern Med. 2004;140:644-649, 650-658