THE AUTOREGULATION OF THE SKIN MICROCIRCULATION IN HEALTHY-SUBJECTS AND DIABETIC-PATIENTS WITH AND WITHOUT VASCULAR COMPLICATIONS

The skin microvascular autoregulatory capacity was investigated in hea lthy volunteers and diabetic patients without or with vascular complic ations. To assess this capacity, skin blood flux (SBF) of different ar eas was examined during different procedures of venous stasis, standin g position, and passive lowering of the leg. SBF was evaluated by lase r doppler fluxmetry. There was, in healthy control subjects, the same degree of vasoconstriction, i.e., the same reduction in SBF irrespecti ve of the site of measurement and the procedure used. In diabetic pati ents, the vasoconstriction elicited in the finger pulp by venous stasi s was normal. By contrast, the vasoconstrictor responses to standing o r lowering of the leg were impaired. In fact there was, in some patien ts, an increased SBF instead of a decreased one during standing or low ering of the leg. Impaired vasoconstrictor responses to standing or lo wering of the leg was observed even in patients without complications; the impairment, however, was more marked in patients with complicatio ns. Thus, the inability of the diabetic skin microvasculature to respo nd normally to postural changes may be an important factor initiating the development of foot complications. The contribution of local and c entral reflexes to microvascular autoregulation in diabetic patients a nd control subjects was also discussed.