  Timely diagnostics of microcirculatory system abnormalities which are the
most severe diabetic complications, is a significant problem of modern health
care. Functional abnormalities manifest themselves earlier than the structural
one and their assessment is the focus of present-day studies. In this study,
the Laser Doppler flowmetry, a noninvasive technique for the cutaneous blood
flow monitoring, was used together with local temperature tests and wavelet
analysis. The study of the blood flow in the microvascular bed of toes was
carried out in control group of 40 subjects, and two diabetic groups differing
in the type of diabetes mellitus (17 of DM1 and 23 of DM2).
  The temperature tests demonstrated that diabetic patients have impaired
vasodilation in response to local heating. The study of oscillating components
shows a significant difference of the spectral properties even in the basal
conditions. Low frequency pulsations of the blood flow associated with
endothelial and activities are lower in both diabetes groups as well as the
ones connected with cardiac activity. Local thermal tests induce variations
both in the perfusion and its spectral characteristics, which are different in
the groups under consideration. We assume that the results obtained provide a
deeper understanding of pathological processes involved in the progress of
microvascular abnormalities due to diabetes mellitus.
