Differences in Skin Microcirculation on the Upper and Lower Extremities in Patients with Diabetes Mellitus: Relationship of Diabetic Neuropathy and Skin Microcirculation

Introduction: During recent years, the role of microcirculation has received increasing attention especially for its potential pathogenic role in the development of diabetes complications, particularly diabetic foot syndrome. The aim of this study was to evaluate the differences in the skin microcirculatory reactivity on the upper and lower extremities (UE and LE, respectively) in the patient with type 2 diabetes mellitus (T2DM). We also evaluated the changes in the skin microcirculation independently of the individual test for peripheral diabetic neuropathy (DN) diagnosis (Semmes-Weinstein monofilaments, Bio-Thesiometer [Bio-Medical Instrument Co., Newbury, OH], and Neuropad((R)) [TRIGOcare International GmbH, Wiehl, Germany]). Patients and Methods: Fifty-two patients with T2DM were enrolled. Microvascular reactivity was measured by laser Doppler iontophoresis, using 1% acetylcholine chloride (ACH) and 1% sodium nitroprusside. Results: Significant reduction of perfusion was found in LE compared with UE when using ACH. In patients with DN skin microvascular reactivity on LE and UE was reduced, compared with patients without DN. Impaired skin microvascular reactivity to ACH (dominant on LE) was demonstrated in all patients who were positive in at least one of the tests for the presence of DN. Conclusions: Reactivity of the skin microcirculation is worse on the foot than on the hand. This study confirmed a close relationship of DN and impaired skin microcirculation. It seems that autonomous neuropathy (assessed using the Neuropad) precedes the manifestation of somatosensory neuropathy.