BIOLOGICAL-ACTIVITY OF C-PEPTIDE ON THE SKIN MICROCIRCULATION IN PATIENTS WITH INSULIN-DEPENDENT DIABETES-MELLITUS

19 insulin-dependent diabetes mellitus (IDDM) patients participated in a randomized double-blind crossover investigation to investigate the impact of human C-peptide on skin microvascular blood flow, The invest igation was also carried out with 10 healthy volunteers. Blood pressur e, heart rate, blood sugar, and C-peptide levels were monitored during a 60-min intravenous infusion period of C-peptide (8 pmol kg(-1) min( -1)) or saline solution (154 mmol liter(-1) NaCl), and 30 min after st opping the infusion. During the same time period, capillary blood cell velocity (CBV), laser Doppler nux (LDF), and skin temperature were as sessed in the feet. In the verum arm, C-peptide levels increased after starting infusion to reach a maximum of 2.3+/-0.2 nmol liter(-1) afte r 45 min, but remained below 0.15 nmol liter(-1) during the saline tre atment. Baseline CBV was lower in diabetic patients compared with heal thy subjects (147+/-3.6 vs. 162+/-4.2 mu m s(-1); P < 0.01). During C- peptide administration, CBV in IDDM patients increased progressively f rom 147+/-3.6 to 167+/-3.7 mu m s(-1); P < 0.001), whereas no signific ant change occurred during saline infusion or in healthy subjects. In contrast to the CBV measurements, the investigation of LDF, skin tempe rature, blood pressure, heart rate, or blood sugar did not demonstrate any significant change during the study. Replacement of human C-pepti de in IDDM patients leads to a redistribution in skin microvascular bl ood flow levels comparable to levels in healthy subjects by increasing the nutritive CBV relative to subpapillary arteriovenous shunt flow.