Skin microvascular reactivity correlates to clinical microangiopathy in type 1 diabetes: A pilot study

AIM: The aim of this study was to investigate the correlation between skin microvascular reactivity and clinical microangiopathy in patients with type 1 diabetes. METHODS: We included 61 patients with type 1 diabetes, that is, 31 patients with and 30 without clinical microangiopathy, and 31 healthy controls. A microangiopathy scoring system was introduced for comparison of data between patients with microangiopathy. Responses to iontophoresis of acetylcholine and sodium nitroprusside were assessed by laser Doppler imaging. RESULTS: Patients with microangiopathy had reduced acetylcholine- and sodium nitroprusside-mediated flux in forearm skin microcirculation compared to healthy controls (p = 0.03 and p < 0.001, respectively, repeated measures analysis of variance), whereas no significant differences were found between patients without microangiopathy and controls. Skin reactivity was reduced in patients with microangiopathy compared to patients without microangiopathy: 1.43 ± 0.38 versus 1.59 ± 0.39 arbitrary units for acetylcholine-mediated peak flux and 1.44 ± 0.46 versus 1.74 ± 0.34 arbitrary units for sodium nitroprusside-mediated peak flux (p < 0.05 for both). A tendency of gradual decrease in acetylcholine and sodium nitroprusside responses was found in patients with increasing microangiopathy scores. CONCLUSION: We conclude that skin microvascular reactivity is associated with clinical microangiopathy in patients with type 1 diabetes. Impaired skin microvascular function in type 1 diabetes seems to be multifactorial and involves both endothelial-dependent and endothelial-independent pathways. We introduce a novel microangiopathy score that could easily be used in a clinical setting for comparison of patients with various degrees of microangiopathy.