| Abstract
| - Background. Few studies have addressed the effect of vasodilatory stimuli on the intrarenal arterial system in type 2 diabetes mellitus (DM), and factors affecting its responsiveness. Methods. One hundred twenty-four patients with type 2 DM without renal failure were enrolled, and 25 subjects served as controls. Using duplex Doppler sonography, resistive indices (RI) of interlobar arteries were measured before and after sublingual nitroglycerine (NTG) (0.3 mg) spray over a 10-min period. Results. Per cent changes in RI (%ΔRI) in the DM group were significantly less than in controls (P<0.05), as was the area over the %ΔRI-time curve (AOC-%ΔRI, total responsiveness to nitroglycerine) (P<0.05). In the DM group, significant negative correlations were found between AOC-%ΔRI and age (r=−0.492, P<0.0001). AOC-%ΔRI in DM patients with proteinuria was significantly lower than without it (P<0.003). AOC-%ΔRI in smokers was also significantly lower than in nonsmokers (P<0.05). By multiple regression analysis of the DM group, AOC-%ΔRI was found to be significantly and independently affected by age (β=−0.394), smoking (β=−0.211), and the presence of proteinuria (β=−0.270; R2=0.354, P<0.0001). Conclusions. Diabetic patients have a lower level of responsiveness to NTG. Advanced age, smoking, and proteinuria significantly affect response to NTG in DM patients, suggesting that advanced intrarenal arteriosclerosis may be contributory. Smoking is suggested to be a risk factor for progression of diabetic nephropathy, likely contributing to poor responsiveness of the intrarenal arterial system to vasodilatory stimuli.
|
