title: Aerobic training workload affects human endothelial cells redox homeostasis.
abstract: OBJECTIVE
  Moderate aerobic exercise reduces oxidative stress, whereas intense physical activity may produce the opposite result. At present, the effects of different exercise loads on oxidative stress markers and the response of human cells to different exercise volumes have not been fully elucidated.
  
  
  METHODS
  Human (Eahy-926) endothelial cells (EC), exposed or not exposed to oxidative stress, were conditioned with sera from two groups of triathletes practicing at different workloads.
  
  
  RESULTS
  Although no differences in functional and hemodynamic variables were observed between the two groups of triathletes, significant changes in some markers for oxidative stress were found in their sera. Thiobarbituric acid reactive substances and superoxide dismutase activity were similar, but triathletes practicing the sport at lower volume (T1) had higher serum nitric oxide and lower catalase activity than triathletes performing the training at greater load (T2). The EC conditioned with serum from T1 (T1-EC) showed higher survival and proliferation rates and lower senescence levels than the EC supplemented with T2 (T2-EC) serum both before and after oxidative stress induction. These effects depended on catalase as demonstrated via enzyme activity inhibition using 3-amino-1,2,4-triazole. After oxidative stress induction, Sirt1 activity, a regulator of the oxidative stress response, was significantly increased in the T1-EC but not in the T2-EC. Moreover, the T1-EC required less catalase activity than the T2-EC to counteract an equal amount of oxidative stress after H2O2 administration.
  
  
  CONCLUSIONS
  This study demonstrates that the beneficial effects of aerobic exercise are eliminated when the training is performed at a greater workload. Moreover, we suggest an oxidative stress marker, serum catalase activity, as a valid tool to use in the supervision of changes to exercise volume.
authors.affiliation: University of Salerno Medical School, Salerno, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Conti
authors.forename: Giusy
authors.initials: G
authors.lastname: Russomanno
authors.forename: Graziamaria
authors.initials: G
authors.lastname: Corbi
authors.forename: Germano
authors.initials: G
authors.lastname: Guerra
authors.forename: Concetta
authors.initials: C
authors.lastname: Grasso
authors.forename: Walter
authors.initials: W
authors.lastname: Filippelli
authors.forename: Virginia
authors.initials: V
authors.lastname: Paribello
authors.forename: Nicola
authors.initials: N
authors.lastname: Ferrara
authors.forename: Amelia
authors.initials: A
authors.lastname: Filippelli
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002374:Catalase / Q000032:analysis; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D042783:Endothelial Cells / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006706:Homeostasis / Q000235:genetics; D006801:Humans; D007558:Italy; D008297:Male; D008969:Molecular Sequence Data; D058451:Oxidative Coupling; D018384:Oxidative Stress / Q000235:genetics; D005082:Physical Exertion / Q000502:physiology*; D013147:Spirometry; D055815:Young Adult
chemical_list: D015415:Biomarkers; D017077:Culture Media, Conditioned; D002374:Catalase