Association between insulin resistance and endothelial dysfunction in renal transplant recipients.
BACKGROUND
Endothelial dysfunction is a common finding in renal transplant recipients (RTR) and is related to impaired local regulation of vasodilative and vasoconstrictive substances, such as nitric monoxide (NO) and endothelin-1 (ET-1). In non-transplanted patients, an association between impaired endothelial function and insulin resistance has been shown. Whether such an association also exists in RTR is unknown.


OBJECTIVE
The aim of the present study was to examine whether insulin resistance is associated with endothelial dysfunction in RTR.


METHODS
A total of 47 RTR in a stable phase six yr post-transplant were included in the statistical analysis. The immunosuppressive therapy was based on cyclosporine and prednisolone. Non-invasive assessment of endothelial function was performed with laser Doppler flowmetry of the forearm skin vasculature after local acetylcholine stimulation. Oral glucose tolerance tests comprising both glucose and insulin measurements were used to calculate insulin sensitivity (IS) indices. NO, ET-1 and von Willebrand factor were measured in fasting plasma samples.


RESULTS
Normal glucose tolerance was found in 31 RTR. In these subjects, both IS (r(2) = 0.164, p = 0.044) and plasma NO (r(2) = 0.326, p = 0.002) were significantly correlated with endothelial function. Patients with glucose intolerance (n = 16) had higher plasma ET-1 and lower NO levels, but the association between IS and endothelial function was not significant in these subjects. In the total patient cohort, IS and endothelial function tended to be correlated (p = 0.127).


CONCLUSIONS
Endothelial dysfunction is significantly associated with insulin resistance in normoglycemic RTR but explains a rather small part of the variation. In glucose-intolerant recipients, IS appears to be more critically dependent on other factors not revealed in the present study.
Voytovich
Monica Hagen
MH
Department of Medicine, Section of Nephrology, Rikshospitalet University Hospital, Oslo, Norway. monica.hagen@rikshospitalet.no
Asberg
Anders
A
Hjelmesaeth
Jøran
J
Jenssen
Trond
T
Hartmann
Anders
A
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D019332:Endothelin-1 / Q000502:physiology; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance; D016030:Kidney Transplantation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000502:physiology; D011183:Postoperative Complications / Q000503:physiopathology; D012189:Retrospective Studies; D014661:Vasoconstriction; D014664:Vasodilation
D001786:Blood Glucose; D019332:Endothelin-1; D009569:Nitric Oxide