Effects of C-peptide on forearm blood flow and brachial artery dilatation in patients with type 1 diabetes mellitus.
Recent studies suggest that C-peptide increases blood flow in both exercising and resting forearm in patients with type 1 diabetes. Now we have studied the effect of C-peptide administration on endothelial-mediated and non-endothelial-mediated arterial responses as well as central haemodynamics in 10 patients with type 1 diabetes in a placebo-controlled double-blind study. Euglycaemia was maintained with an i.v. insulin infusion before and during the study. A high-resolution ultrasound technique and Doppler echocardiography were used to assess haemodynamic functions. Brachial artery blood flow and brachial artery diameter were measured in the basal state, 1 and 10 min after reactive hyperaemia and 4 min after sublingual glyceryl trinitrate administration (GTN; endothelial-independent vasodilatation), both before and after the end of 60-min C-peptide (6 pmol kg-1 min-1) or saline infusion periods. Echocardiographic measurements were also performed before and at the end of the infusion periods. Seven healthy age-matched males served as controls for vascular studies. The patients showed a blunted brachial dilatation after reactive hyperaemia in comparison with the healthy controls (2.1 +/- 0.5% vs. 9.3 +/- 0.3%, P < 0.001), indicating a disturbed endothelial function. C-peptide infusion compared with saline resulted in increased basal blood flow (33 +/- 6%, P < 0.001) and brachial arterial dilatation (4 +/- 1%, P < 0.05). Left ventricular ejection fraction seemed to be improved (5 +/- 2%, P < 0.05) at the end of C-peptide infusion compared with placebo. The vascular response to reactive hyperaemia and GTN was not affected by C-peptide infusion. Our results demonstrate that physiological concentrations of C-peptide increase resting forearm blood flow, brachial artery diameter and left ventricular systolic function in patients with type 1 diabetes.
Fernqvist-Forbes
E
E
Department of Surgical Sciences, Section of Clinical Physiology, Karolinska Hospital, Stockholm, Sweden.
Johansson
B L
BL
Eriksson
M J
MJ
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D001916:Brachial Artery / Q000187:drug effects*; D002096:C-Peptide / Q000494:pharmacology*; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D015150:Echocardiography, Doppler; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D012039:Regional Blood Flow / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin