L-arginine: a new opportunity in the management of clinical derangements in dialysis patients.

L-Arginine is an essential amino acid for infants and growing children, as well as for pregnant women. This amino acid is a substrate for at least 5 enzymes identified in mammals, including arginase, arginine-glycine transaminase, kyotorphine synthase, nitric oxide synthase, and arginine decarboxylase. L-arginine is essential for the synthesis of creatine, urea, polyamines, nitric oxide, and agmatine. Arginine may be considered an essential amino acid in sepsis, and its supplementation could be beneficial in this clinical setting by improving microcirculation and protein anabolism. Rats receiving arginine-supplemented parenteral nutrition showed an increased ability to synthesize acute phase proteins when challenged with sepsis. Finally, L-arginine exerts antihypertensive and antiproliferative effects on vascular smooth muscles. It has been shown to reduce systemic blood pressure in some forms of experimental hypertension. Endothelial dysfunction and reduced nitric oxide bioactivity are associated with increased incidence of cardiovascular diseases. A beneficial effect of acute and chronic L-arginine supplementation on endothelial derived nitric oxide production and endothelial function has been shown. In end-stage renal disease patients, the rate of de novo arginine synthesis seemed to be preserved. Our preliminary data on a group of dialysis patients showed that predialysis arginine levels were stable in a normal range during the dialysis session and that hypertensive patients had lower arginine-citrulline ratio than normotensive patients.