title: Effects of moderate-intensity physical exercise on pharmacokinetics of factor VIII and von Willebrand factor in young adults with severe haemophilia A: a pilot study.
abstract: BACKGROUND
  In persons with severe haemophilia A (pwshA), infused factor VIII (FVIII) half-life can vary according to such determinants as blood group, von Willebrand factor (VWF) level or age; however, FVIII pharmacokinetics (PK) has not been well studied in pwshA during exercise.
  
  
  OBJECTIVE
  To investigate FVIII PK in pwshA performing moderate-intensity aerobic exercise.
  
  
  METHODS
  Twelve young-adult pwshA with the intron-22 inversion mutation, on relatively low-dose FVIII prophylaxis regimens, and relatively good musculoskeletal status were recruited. Abbreviated PK of FVIII activity and von Willebrand factor antigen (VWF:Ag) level were compared - during rest, and with 60-min exercise (2 × 15 min each of moderate-intensity stationary cycling and treadmill walking). During rest and exercise visits, a baseline blood specimen was drawn, routine prophylaxis FVIII infused; then six blood specimens were taken over the following 24 h.
  
  
  RESULTS
  For all subjects, mean half-life of infused FVIII did not change significantly with exercise vs. at rest (577 ± 190 vs. 614 ± 163 min; P = 0.4131). VWF:Ag rose transiently by 40-50% for 6-8 h with exercise (P < 0.01), particularly in non-O blood group subjects. No musculoskeletal bleeds occurred during the study.
  
  
  CONCLUSIONS
  Four × 15 min of moderate-intensity aerobic exercise increased VWF:Ag levels for 6-8 h, and showed no evidence of accelerated FVIII clearance or of musculoskeletal bleeding in these young-adult pwshA with relatively good musculoskeletal status, on relatively low-dose FVIII prophylaxis regimens. However, O blood group impact would merit larger studies, with longer durations of similar or more vigorous exercise intensities.
authors.affiliation: Centre d'hémostase pédiatrique et adulte du CHU Sainte-Justine, Montréal, QC, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Zourikian
authors.affiliation: Centre d'hémostase pédiatrique et adulte du CHU Sainte-Justine, Montréal, QC, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Merlen
authors.affiliation: Centre d'hémostase pédiatrique et adulte du CHU Sainte-Justine, Montréal, QC, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Bonnefoy
authors.affiliation: Centre d'hémostase pédiatrique et adulte du CHU Sainte-Justine, Montréal, QC, Canada.
authors.forename: J
authors.initials: J
authors.lastname: St-Louis
authors.affiliation: Centre d'hémostase pédiatrique et adulte du CHU Sainte-Justine, Montréal, QC, Canada.
authors.forename: G E
authors.initials: GE
authors.lastname: Rivard
mesh_terms: D000293:Adolescent; D000328:Adult; D001780:Blood Coagulation Tests; D001789:Blood Group Antigens / Q000378:metabolism; D018450:Disease Progression; D015444:Exercise; D005169:Factor VIII / Q000493:pharmacokinetics* / Q000627:therapeutic use; D005260:Female; D006207:Half-Life; D006467:Hemophilia A / Q000188:drug therapy*; D006801:Humans; D008297:Male; D010865:Pilot Projects; D055815:Young Adult; D014841:von Willebrand Factor / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D001789:Blood Group Antigens; D014841:von Willebrand Factor; D005169:Factor VIII
keywords: exercise; factor VIII; half-life; pharmacokinetics; severe haemophilia A; von Willebrand factor