Aims: Endothelin-1 levels are elevated in patients with type 2 diabetes mellitus and may contribute to impaired microvascular function. We investigated the effect of selective endothelin-A (ET(A)) receptor blockade (BQ123) on skin microcirculation in patients with type 2 diabetes and albuminuria.
Methods: Ten type 2 diabetes patients and 8 non-diabetic controls were investigated. Nutritive skin capillary circulation, investigated by videophotometric capillaroscopy, and total skin microcirculation, assessed by laser Doppler flux-metry (LDF), were studied during intra-arterial infusion of saline for 15 min, followed by BQ123 infusion for 60 min.
Results: Following BQ123 infusion there was a significant increase in resting capillary blood cell velocity (CBV) in patients with type 2 diabetes from 0.24 (0.20-0.34) mm/s at baseline to 0.61 (0.46-0.88) mm/s at 60 min, but no significant change in the control subjects [0.55 (0.10-0.68) vs. 0.38 (0.13-0.88) mm/s; p < 0.005 for difference between groups]. Peak CBV following arterial occlusion and skin temperature increased significantly in the type 2 diabetes group but not in the control group during BQ123 infusion. There were no significant changes in LDF parameters during infusion of BQ123 in either group.
Conclusion: ET(A) receptor blockade improves nutritive skin capillary circulation in patients with type 2 diabetes and microangiopathy.
(c) 2008 S. Karger AG, Basel.