AIMS/HYPOTHESIS: In recent years, evidence has arisen that proinsulin C-peptide exerts biological effects especially on microcirculation, e.g. C-peptide has been shown to increase skin microcirculation in patients with Type I (insulin-dependent) diabetes mellitus and to activate endothelial nitric oxide synthase. This study aimed to investigate the influence of pro-insulin C-peptide on erythrocyte deformability which was assessed by means of laser diffractoscopy. METHODS: Blood samples from healthy control subjects (n = 10) and Type I diabetic patients (n = 15) completely deficient of C-peptide were analysed at shear stresses ranging from 0.3 to 30 Pa. RESULTS: Erythrocyte deformability was lower in the group of Type I diabetic patients than in the control subjects. Preincubation of the diabetic blood samples with various concentrations of human proinsulin C-peptide for 8 h restored the deformability of erythrocytes, almost reaching the values of control samples. In contrast, proinsulin C-peptide did not modify the erythrocyte deformability of control subjects. CONCLUSION/ INTERPRETATION: We conclude that proinsulin C-peptide is able to ameliorate the impaired deformability of erythrocytes in Type I diabetic patients and we hypothesise that this effect is mediated by restoration of Na(+)-K(+)-ATPase activity, which is known to be attenuated in diabetic patients.
AIMS/HYPOTHESIS: In recent years, evidence has arisen that proinsulin C-peptide exerts biological effects especially on microcirculation, e.g. C-peptide has been shown to increase skin microcirculation in patients with Type I (insulin-dependent) diabetes mellitus and to activate endothelial nitric oxide synthase. This study aimed to investigate the influence of pro-insulin C-peptide on erythrocyte deformability which was assessed by means of laser diffractoscopy. METHODS: Blood samples from healthy control subjects (n = 10) and Type I diabeticpatients (n = 15) completely deficient of C-peptide were analysed at shear stresses ranging from 0.3 to 30 Pa. RESULTS: Erythrocyte deformability was lower in the group of Type I diabeticpatients than in the control subjects. Preincubation of the diabetic blood samples with various concentrations of humanproinsulin C-peptide for 8 h restored the deformability of erythrocytes, almost reaching the values of control samples. In contrast, proinsulin C-peptide did not modify the erythrocyte deformability of control subjects. CONCLUSION/ INTERPRETATION: We conclude that proinsulin C-peptide is able to ameliorate the impaired deformability of erythrocytes in Type I diabeticpatients and we hypothesise that this effect is mediated by restoration of Na(+)-K(+)-ATPase activity, which is known to be attenuated in diabeticpatients.
Authors: R Rigler; A Pramanik; P Jonasson; G Kratz; O T Jansson; P Nygren; S Stâhl; K Ekberg; B Johansson; S Uhlén; M Uhlén; H Jörnvall; J Wahren Journal: Proc Natl Acad Sci U S A Date: 1999-11-09 Impact factor: 11.205