We investigated an effect of uraemia on structural and functional features of human resistance vasculature. Arteries (≈ 200 μm) isolated from subcutaneous fat biopsies obtained from 35 ESRD (end-stage renal disease) patients starting peritoneal dialysis and 30 matched controls were studied using isolated small artery bioassays. Flow-mediated dilatation was attenuated in ESRD patients compared with controls. NO (nitric oxide) contribution to flow was lacking in ESRD patients, but present in the controls. ADMA (asymmetrical dimethyl L-arginine) levels were higher in the ESRD group compared with the control group. Dilatation in response to acetylcholine was reduced in ESRD patients compared with controls, but response to NO donor was similar. Expression of nitrotyrosine and heat shock proteins 70 and 27, but not 90, was increased in arteries from ESRD patients compared with controls. Arterial remodelling was absent in ESRD patients. There was no difference between the groups in myogenic tone, vascular reactivity or sensitivity to several vasoconstrictors. Arterial distensibility, reflecting passive properties of the vascular wall, was reduced in ESRD patients compared with controls. Exclusion of ESRD patients with diabetes and/or cardiovascular disease from analyses had no influence on the main findings. Thus we propose that uraemia has a strong impact on endothelial function and passive properties of the arterial wall of human peripheral resistance vasculature. The reduced contribution of NO to flow stimulus via enhanced nitrosative stress and higher plasma concentrations of ADMA may suggest potential mechanisms behind endothelial dysfunction in the resistance peripheral circulation in ESRD.

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