Systemic effects of low-intensity laser irradiation on skin microcirculation in patients with diabetic microangiopathy

Low-intensity laser irradiation has been shown to induce wound healing in conditions of reduced microcirculation, which is in part explained by systemic effects. We therefore investigated such a potential systemic effect of low-intensity laser irradiation on skin blood circulation in patients with diabetic microangiopathy. Patients with diabetic microangiopathy were randomized to receive either a single helium-neon (HeNe, 632.8 nm) low-intensity laser irradiation with a dose of 30 j/cm(2) or a sham irradiation over the forefoot region in a double-blind, placebo-controlled clinical study. Skin blood circulation by means of temperature recordings over forefoot regions was detected by infrared thermography. Following a single transcutaneous low-intensity laser irradiation, a rise in skin temperature in both feet of the subjects in the laser group was noted, whereas in both feet of the subjects in the placebo group a drop in skin temperature occurred. The baseline-adjusted skin temperature 15 min after the end of the irradiation was significantly higher in the laser-treated forefeet compared to the placebo"treated" forefeet (p < 0.0001); the baseline-adjusted difference in the temperature was 1.94 +/- 0.35degreesC. Simultaneously, the baseline-adjusted skin temperature was significantly higher in the laser-untreated forefeet compared to the placebo-"untreated" forefeet (P < 0.0001); the baseline-adjusted difference was 1.70 +/- 0.33degreesC. Our data show a significant increase in skin circulation due to athermic laser irradiation in patients with diabetic microangiopathy and point to the possibility of inducing systemic effects. (C) 2002 Elsevier Science (USA).