title: Effects of L-arginine supplementation on blood flow, oxidative stress status and exercise responses in young adults with uncomplicated type I diabetes.
abstract: OBJECTIVE
  Vascular disease is the principal cause of death and disability in patients with diabetes, and endothelial dysfunction seems to be the major cause in its pathogenesis. Since L-arginine levels are diminished in conditions such as type 1 and type 2 diabetes, in this work we aimed to verify the effects of L-arginine supplementation (7 g/day) over the endothelial function and oxidative stress markers in young male adults with uncomplicated type 1 diabetes. We also investigated the influences of L-arginine administration on vascular/oxidative stress responses to an acute bout of exercise.
  
  
  METHODS
  Ten young adult male subjects with uncomplicated type 1 diabetes and twenty matched controls volunteered for this study. We analysed the influence of L-arginine supplementation (7 g/day during 1 week) over lower limb blood flow (using a venous occlusion plethysmography technique), oxidative stress marker (TBARS, Carbonyls), anti-oxidant parameters (uric acid and TRAP) and total tNOx in rest conditions and after a single bout of submaximal exercise (VO₂ at 10 % below the second ventilatory threshold). Data described as mean ± standard error (SE). Alpha level was P < 0.05.
  
  
  RESULTS
  Glycaemic control parameters were altered in type 1 diabetic subjects, such as HbA1c (5.5 ± 0.03 vs. 8.3 ± 0.4 %) and fasted glycaemia (94.8 ± 1.4 vs. 183 ± 19 mg/dL). Oxidative stress/damage markers (carbonyls and TBARS) were increased in the diabetic group, while uric acid was decreased. Rest lower limb blood flow was lower in type 1 diabetic subjects than in healthy controls (3.53 ± 0.35 vs. 2.66 ± 0.3 ml 100 ml⁻¹ min⁻¹). L-Arginine supplementation completely recovered basal blood flow to normal levels in type 1 diabetics' subjects (2.66 ± 0.3 to 4.74 ± 0.86 ml 100 ml⁻¹ min⁻¹) but did not interfere in any parameter of redox state or exercise.
  
  
  CONCLUSIONS
  Our findings highlight the importance of L-arginine for the improvement of vascular function in subjects with diabetes, indicating that L-arginine supplementation could be an essential tool for the treatment for the disease complications, at least in non-complicated diabetes. However, based on our data, it is not possible to draw conclusions regarding the mechanisms by which L-arginine therapy is inducing improvements on cardiovascular function, but this important issue requires further investigations.
authors: Laboratório de Pesquisa do Exercício, Escola de Educação Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors: Ana Paula Trussardi
authors: AP
authors: Fayh
authors: Mauricio
authors: M
authors: Krause
authors: Josianne
authors: J
authors: Rodrigues-Krause
authors: Jerri Luiz
authors: JL
authors: Ribeiro
authors: Jorge Pinto
authors: JP
authors: Ribeiro
authors: Rogério
authors: R
authors: Friedman
authors: José Cláudio Fonseca
authors: JC
authors: Moreira
authors: Alvaro
authors: A
authors: Reischak-Oliveira
mesh_terms: D000293:Adolescent; D000328:Adult; D001120:Arginine / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D001775:Blood Circulation; D001938:Brazil / Q000453:epidemiology; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications / Q000178:diet therapy* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000453:epidemiology / Q000517:prevention & control*; D019587:Dietary Supplements; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000503:physiopathology; D005080:Exercise Test; D006801:Humans; D035002:Lower Extremity / Q000098:blood supply; D008297:Male; D009043:Motor Activity; D018384:Oxidative Stress; D012039:Regional Blood Flow; D012307:Risk Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001120:Arginine