Detection and characterisation of microcirculatory abnormalities in the skin of diabetic patients with microvascular complications.

The aim of this study was to characterise microvascular blood flow in the skin and to compare it with biomarkers of endothelial dysfunction and tissue inflammation in patients with type 2 diabetes with (n=20) or without (n=20) microvascular complications and 20 control subjects. Microvascular function was measured by laser Doppler velocimetry in combination with iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP). Blood was collected for measurement of biomarkers including plasminogen activator inhibitor-1 (PAI-1), soluble intercellular adhesion molecule (sICAM), soluble vascular cell adhesion molecule (sVCAM) and high-sensitivity C-reactive protein (hsCRP). Both ACh and SNP responses fall progressively with the development of diabetes and microvascular complications. For the total cohort, there was a significant overall correlation between ACh and SNP response (r=0.7, p<0.0001), and this relationship was particularly strong in those with microvascular complications. There was a trend towards higher hsCRP levels across the three groups, but no difference in other biomarkers. Abnormalities of microvascular blood flow are evident in diabetes and become more marked with the development of microvascular complications. This relationship was similar to that shown by the marker of inflammation (hsCRP), but stronger than that pertaining to biomarkers of endothelial function. As both ACh and SNP responses are attenuated, the disturbance is not characteristic of endothelial dysfunction alone.