Arginine, arginine analogs and nitric oxide production in chronic kidney disease

Production of nitric oxide (NO) is reduced in chronic kidney disease and end-stage renal disease. Data support the conclusion that low NO levels, probably a function of perturbed endothelial synthesis, contribute to progressive kidney dysfunction. Chris Baylis outlines the mechanisms by which NO deficiency can develop in renal disease states, and discusses the potential for developing new treatments by manipulating NO biosynthetic pathways. Nitric oxide (NO) production is reduced in renal disease, partially due to decreased endothelial NO production. Evidence indicates that NO deficiency contributes to cardiovascular events and progression of kidney damage. Two possible causes of NO deficiency are substrate ( L -arginine) limitation and increased levels of circulating endogenous inhibitors of NO synthase (particularly asymmetric dimethylarginine [ADMA]). Decreased L -arginine availability in chronic kidney disease (CKD) is due to perturbed renal biosynthesis of this amino acid. In addition, inhibition of transport of L -arginine into endothelial cells and shunting of L -arginine into other metabolic pathways (e.g. those involving arginase) might also decrease availability. Elevated plasma and tissue levels of ADMA in CKD are functions of both reduced renal excretion and reduced catabolism by dimethylarginine dimethylaminohydrolase (DDAH). The latter might be associated with loss-of-function polymorphisms of a DDAH gene, functional inhibition of the enzyme by oxidative stress in CKD and end-stage renal disease, or both. These findings provide the rationale for novel therapies, including supplementation of dietary L -arginine or its precursor L -citrulline, inhibition of non-NO-producing pathways of L -arginine utilization, or both. Because an increase in ADMA has emerged as a major independent risk factor in end-stage renal disease (and probably also in CKD), lowering ADMA concentration is a major therapeutic goal; interventions that enhance the activity of the ADMA-hydrolyzing enzyme DDAH are under investigation. Key Points Production of nitric oxide (NO; from L -arginine and O 2 via nitric oxide synthase [NOS]) is reduced in renal disease As chronic NOS inhibition produces hypertension and renal dysfunction in animals, NO deficiency probably contributes to progression of kidney disease in humans Net NO deficiency can develop in response to decreased substrate availability (e.g. perturbed synthesis or transport of arginine) and the action of endogenous NOS