Recovery of 0,1 Hz microvascular skin blood flow in dysautonomic diabetic (Type 2) neuropathy by using frequency rhythmic electrical modulation system (FREMS)

Abstract

Synchronized oscillation of smooth muscle cells tension in arterioles is the main control system of microvascular skin blood flow. An important autogenic vasomotion activity is recognized in the 0,1 Hz oscillations observed with power spectrum analysis of laser doppler flowmetry. Severe dysautonomia in diabetic neuropathy is correlated with the loss of 0,1 Hz vasomotion activity, hence with the impaired blood microcirculation. FREMS (Aptiva, Lorenz Biotech Spa - Italy) is a novel transcutaneous electrotherapy characterized by sequences of high voltage and low pulse duration electrical stimuli which vary in both frequency and duration. We evaluated the changes in laser doppler flow (Periflux System 5000 Perimed) in the volar part of the forearm before, during and after FREMS stimulation. Normal controls (n=10, 6 female, age range 21-39 years) demonstrated significant 0,1 Hz vasomotion power spectra in the basal condition associated with large oscillations of adrenergic cuteanous sweath activity (CED Model 2502 Skin Conductance unit) sampled from the hand; diabetics of type 2 with severe dysautonomic impairment (n = 10, 5 female, age range 63-75 years) displayed a near total absence (n=4) or an important decrease (n = 6) of 0,1 Hz vasomotion power spectra. During and until few minutes after FREMS application in both control and diabetics groups we observed a significant (p < 0,001) increase of 0,1 Hz vasomotion power spectra, despite in diabetics group adrenergic cutaneous sweath activity remained suppressed. These vasomotion power spectral variations were always related to the variations of blood flow velocity. Synchronization of smooth muscle cell activity is thought to initiate in the presence of endothelium and is related to repetitive transitory cGMP mediated release and reuptake of calcium from the sarcoplasmic reticulum of the smooth cells. We suggest that FREMS is able to synchronize the smooth cells activity, inducing and increasing 0,1 Hz vasomotion activity, indipendently from the autonomic nervous system.