title: L-arginine supplementation improves exercise capacity after a heart transplant.
abstract: BACKGROUND
  Endothelial dysfunction is associated with the decreased exercise capacity observed in heart-transplant (HTx) recipients. L-arginine supplementation (LAS) stimulates the nitric oxide (NO) pathway and restores endothelial function.
  
  
  OBJECTIVE
  We compared exercise capacity in healthy subjects and HTx patients and investigated whether chronic LAS might improve exercise capacity and NO/endothelin balance after an HTx.
  
  
  METHODS
  Clinical, echocardiographic, and exercise characteristics were measured in 11 control subjects and 22 HTx recipients. In a prospective, double-blind study, the 22 HTx recipients performed a 6-min exercise [6-min-walk test (6MWT)] and a maximal bicycle exercise test before and after a 6-wk period of placebo intake or LAS. Endothelial function was measured by analyzing blood NO metabolites, endothelin, and the resulting NO/endothelin balance.
  
  
  RESULTS
  Exercise capacity decreased after transplantation. Unlike with the placebo intake, 6 wk of LAS improved quality of life in HTx recipients (mean +/- SEM Minnesota Score: from 15.3 +/- 1.3 to 10.6 +/- 1.1; P < 0.001) and their submaximal exercise capacity. The distance walked during the 6MWT increased (from 525 +/- 20 to 580 +/- 20 m; P = 0.002), and the ventilatory threshold during the incremental test was delayed by 1.2 min (P = 0.01). Central factors such as resting stroke volume, systolic pulmonary arterial pressure, cardiac systolodiastolic functions, and heart-rate reserve were not modified, but LAS significantly increased the NO:endothelin ratio (from 2.49 +/- 0.38 to 3.31 +/- 0.39; P = 0.03).
  
  
  CONCLUSIONS
  Oral LAS may be a useful adjuvant therapeutic to improve quality of life and exercise tolerance in HTx recipients.
authors.affiliation: Medicine Faculty, Physiology Institute, Strasbourg, France. stephane.doutreleau@chru-strasbourg.fr
authors.forename: Stéphane
authors.initials: S
authors.lastname: Doutreleau
authors.forename: Olivier
authors.initials: O
authors.lastname: Rouyer
authors.forename: Paola
authors.initials: P
authors.lastname: Di Marco
authors.forename: Evelyne
authors.initials: E
authors.lastname: Lonsdorfer
authors.forename: Ruddy
authors.initials: R
authors.lastname: Richard
authors.forename: François
authors.initials: F
authors.lastname: Piquard
authors.forename: Bernard
authors.initials: B
authors.lastname: Geny
mesh_terms: D001120:Arginine / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D016572:Cyclosporine / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D004452:Echocardiography; D019332:Endothelin-1 / Q000097:blood; D016232:Endothelins / Q000097:blood; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D016027:Heart Transplantation / Q000502:physiology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood / Q000627:therapeutic use; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood; D018579:Patient Selection; D010919:Placebos; D011651:Pulmonary Artery / Q000187:drug effects / Q000502:physiology / Q000503:physiopathology; D011788:Quality of Life
chemical_list: D019332:Endothelin-1; D016232:Endothelins; D007166:Immunosuppressive Agents; D010919:Placebos; D009569:Nitric Oxide; D016572:Cyclosporine; D001120:Arginine