C-Peptide Exerts Beneficial Effects on Myocardial Blood Flow and Function in Patients With Type 1 Diabetes

C-Peptide Exerts Beneficial Effects on Myocardial Blood Flow and Function in Patients With Type 1 Diabetes Alexander Hansen 1 , Bo-Lennart Johansson 2 , John Wahren 2 and Helene von Bibra 1 1 Section of Cardiology, Department of Medicine, Karolinska Hospital, Stockholm, Sweden 2 Section of Clinical Physiology, Department of Surgical Sciences, Karolinska Hospital, Stockholm, Sweden Abstract Myocardial dysfunction, perfusion abnormalities, and the extent to which these abnormalities may be reversed by C-peptide administration was assessed in type 1 diabetic patients. Eight patients were studied before and during a 0.84-mg/kg dipyridamole administration using a randomized double-blind crossover protocol with infusion of C-peptide (6 pmol · kg −1 · min −1 ) or saline during 60 min on two different days. Myocardial function was measured as peak myocardial velocity during systole (Vs) and early diastole (Vd) by pulsed tissue Doppler imaging. Myocardial contrast echocardiography was used for assessment of myocardial blood volume (SI max ) and myocardial blood flow index (MBFI) calculated from the relation between trigger interval and signal intensity. Eight age-matched healthy volunteers served as control subjects. In the basal state, Vd (13.8 ± 0.6 vs. 15.6 ± 0.5 cm/s, P < 0.04) and SI max (6.6 ± 0.6 vs. 8.2 ± 0.6 a.u. P < 0.04) were reduced in patients compared with control subjects. Dipyridamole administration significantly increased indexes of myocardial function and blood flow to a similar extent in patients and control subjects. During C-peptide administration, Vs and Vd increased by 12% ( P = 0.03), SI max increased from 6.6 ± 0.6 to 8.1 ± 0.7 a.u. ( P < 0.02), and MBFI increased from 3.3 ± 0.4 to 5.3 ± 0.9 ( P < 0.05). The results demonstrate that type 1 diabetic patients have impaired myocardial function and perfusion in the basal state that can be improved by short-term replacement of C-peptide. Footnotes Address correspondence and reprint requests to Professor Helene von Bibra, Section of Cardiology N3:05, Karolinska Hospital, SE-17176 Stockholm, Sweden. E-mail: helene.vonbibra{at}ks.se . Received for publication 21 February 2002 and accepted in revised form 12 July 2002. CV, coefficient of variation; MBFI, myocardial blood flow index; PET, positron emission tomography; SI, signal intensity; SI max , myocardial blood volume; Va, late diastolic velocity; Vd, velocity during early diastole; Vs, velocity during systole. DIABETES