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Nitric oxide modulation of renal and cardiac hemodynamics in type 2 diabetes
Michele Dalla Vestra1, David Sacerdoti, Giancarlo Bombonato
1Department of Medical and Surgical Sciences, Clinica Medica I, University of Padova, Via Giustiniani 2, 35128, Italy. michele.dallavestra@unipd.it
Objective:
To evaluate endothelial function in type 2 diabetic patients with and without diabetic nephropathy.
Methods:
We studied the effects of systemic infusion of the nitric oxide (NO) synthase inhibitor NG-monomethyl-l-arginine (L-NMMA) on cardiovascular and renal hemodynamics in six type 2 diabetic patients with microalbuminuria (D2-MA), six type 2 diabetic patients with normoalbuminuria (D2-NA) and five control subjects. Both type 2 diabetic patients and control subjects had mild arterial hypertension.
Results:
L-NMMA infusion decreased the cardiac index in all groups. A reduction in glomerular filtration rate (GFR) and an increase in filtration fraction were observed only in controls. Renal plasma flow decreased in controls and D2-NA patients and renal vascular resistance increased in all groups.
Conclusions:
The effect of L-NMMA on cardiac output was similar in controls and type 2 diabetic patients with and without diabetic nephropathy. In contrast, the effect on GFR was impaired in both diabetic groups, suggesting that glomerular NO homeostasis is altered in type 2 diabetes. Moreover the discrepancy, in diabetic patients, between cardiac and renal effects during L-NMMA infusion suggests that the modulation of glomerular hemodynamics is independent from NO-regulated cardiac output.