Attenuated cutaneous microvascular function in healthy young African Americans: Role of intradermal l-arginine supplementation

Publication date: July 2018 Source:Microvascular Research, Volume 118 Author(s): Kiyoung Kim, Chansol Hurr, Jordan C. Patik, R. Matthew Brothers It has been established that endothelial function in conduit vessels is reduced in young African Americans (AA) relative to Caucasian Americans (CA). However, less is known regarding endothelial function in microvasculature of young AA. We hypothesized that microvascular function in response to local heating of skin is attenuated in young AA relative to age-matched CA due largely to the lack of NO bioavailability, which is in turn improved by intradermal l-arginine supplementation and/or inhibition of arginase. Nine AA and nine CA adults participated in this study. Participants were instrumented with four microdialysis membranes in the cutaneous vasculature of one forearm and were randomly assigned to receive 1) lactated Ringer's solution as a control site; 2) 20 mM NG-nitro-l-arginine (l-NAME) to inhibit NO synthase activity; 3) 10 mM l-arginine to local supplement l-arginine; or 4) a combination of 5.0 mM (S)-(2‑boronoethyl)-l-cysteine-HCL (BEC) and 5.0 mM Nω-hydroxy-nor-l-arginine (nor-NOHA) at a rate of 2.0 μl/min to locally inhibit arginase activity. Cutaneous vascular conductance (CVC) was calculated as red blood cell flux divided by mean arterial pressure. All CVC data were presented as a percentage of maximal CVC (%CVCmax) that was determined by maximal cutaneous vasodilation induced by 44 °C heating pl...
Source: Microvascular Research - Category: Biochemistry Source Type: research