Women with a history of gestational diabetes mellitus have preserved sensory nerve-mediated dilatation in the cutaneous microvasculature.

Women with a history of gestational diabetes mellitus (GDM) have a greater risk of developing type 2 diabetes mellitus and cardiovascular disease than healthy control (HC) women who had an uncomplicated pregnancy. Microvascular endothelial dysfunction, mediated by reduced nitric oxide (NO)-dependent mechanisms, persists after GDM. However, it is unknown whether cutaneous sensory nerve-mediated dilatation is similarly reduced in these women. We hypothesised that women with a history of GDM would exhibit attenuated sensory nerve-mediated vasodilatation compared with HC women. One intradermal microdialysis fibre was placed in the ventral forearm of 30 HC and 22 GDM women for the local delivery of lactated Ringer's solution during a local heating protocol (42°C; 0.1°C s-1). The heater remained at 42°C until blood flow plateaued (∼40 min). Next, the site was perfused with 15 mM NG-nitro-l-arginine methyl ester (a NO synthase inhibitor; ∼40 min) to determine NO-dependent dilatation. Red blood cell flux was measured by laser-Doppler flowmetry (LDF). Cutaneous vascular conductance was calculated (CVC = LDF/mean arterial pressure) and normalized to maximum (28 mM sodium nitroprusside + local heat 43°C). The initial sensory nerve-mediated peak response was not different between groups (P = 0.623). The endothelium-dependent plateau (P < 0.001) and NO contribution to the plateau (P < 0.01) were attenuated in GDM compared with HC women. Our findings suggest that despite reductions in endothelium- and NO-dependent dilatation, women who had GDM do not exhibit impairments in local cutaneous sensory nerve-mediated vasodilatation compared with HC women.