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Acute, local effects of iontophoresed insulin and C‐peptide on cutaneous microvascular function in Type 1 diabetes mellitus
Author(s) -
Delaney C.,
Shaw J.,
Day T.
Publication year - 2004
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.2004.01167.x
Subject(s) - medicine , c peptide , sodium nitroprusside , vasodilation , iontophoresis , insulin , endocrinology , diabetes mellitus , endothelium , peptide , microcirculation , acetylcholine , type 2 diabetes mellitus , pharmacology , nitric oxide , biochemistry , biology , radiology
Aim The aim of the present study was to demonstrate acute, local vasodilatatory effects of insulin and C‐peptide on cutaneous microvascular function in Type 1 diabetic subjects. There are no published data available examining physiological effects of C‐peptide delivered in this way. Methods The study included 20 participants with C‐peptide‐deficient Type 1 diabetes mellitus. Cutaneous microvascular function was assessed on the forearm using laser Doppler velocimetry. Insulin, C‐peptide, acetylcholine (ACh), sodium nitroprusside (SNP) and saline were delivered through the skin using iontophoresis. The response was measured as percentage increase in flux above baseline. Results C‐peptide delivered by iontophoresis produced a vasodilatatory response greater than the response to saline (289.5 ± 265.9% vs. 105.1 ± 163.6%, P = 0.003). The response to C‐peptide was also shown to be dose dependent. Further, the size of the response to C‐peptide correlated well with the size of the response to the endothelium‐dependent vasodilatator ACh ( r = 0.666, P = 0.001) but not with the size of the response to the endothelium‐independent vasodilator SNP ( r = 0.345, P > 0.05). Conclusions Physiological effects of C‐peptide on cutaneous microvascular function could be demonstrated in individuals with Type 1 diabetes. The results support both physiological activity of C‐peptide and an endothelium‐dependent mechanism similar to that of ACh. The technique reported may be useful in investigating vasoactive actions of C‐peptide in a safe and non‐invasive way.