Microvascular reactivity to thermal stimulation in patients with diabetes mellitus and polyneuropathy

The study aimed to investigate local thermally induced microvascular reactivity in patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM) and polyneuropathy and to compare it with healthy controls. A hundred and fourteen subjects were investigated divided into 3 groups: 1st group -20 patients with T1DM; 2nd group -50 patients with T2DM; 3rd group -44 healthy controls. The skin perfusions of the first tiptoe were monitored by laser Doppler flowmetry during thermal test. The initial (PUi) and basal perfusions at 32°C (PUb) tended to be higher in the DM groups and the PUb of T1DM group was higher compared with the healthy subjects. The perfusion responses to heating were attenuated in the patients compared with the controls. The calculated vasodilator heat-induced indices were significantly lower and the vasoconstrictor indices during relative cooling in the recovery period were significantly higher in DM patients related to the healthy subjects. The reduced cutaneous microvascular responses to local thermal stimulation in the plantar sides of the toes of both T1DM and T2DM patients with polyneuropathy were similar to those found by previous studies in other investigated sites of glabrous and nonglabrous skin of patients with DM.