title: Normal muscle oxygen consumption and fatigability in sickle cell patients despite reduced microvascular oxygenation and hemorheological abnormalities.
abstract: OBJECTIVE
  Although it has been hypothesized that muscle metabolism and fatigability could be impaired in sickle cell patients, no study has addressed this issue.
  
  
  METHODS
  We compared muscle metabolism and function (muscle microvascular oxygenation, microvascular blood flow, muscle oxygen consumption and muscle microvascular oxygenation variability, which reflects vasomotion activity, maximal muscle force and local muscle fatigability) and the hemorheological profile at rest between 16 healthy subjects (AA), 20 sickle cell-hemoglobin C disease (SC) patients and 16 sickle cell anemia (SS) patients.
  
  
  RESULTS
  Muscle microvascular oxygenation was reduced in SS patients compared to the SC and AA groups and this reduction was not related to hemorhelogical abnormalities. No difference was observed between the three groups for oxygen consumption and vasomotion activity. Muscle microvascular blood flow was higher in SS patients compared to the AA group, and tended to be higher compared to the SC group. Multivariate analysis revealed that muscle oxygen consumption was independently associated with muscle microvascular blood flow in the two sickle cell groups (SC and SS). Finally, despite reduced muscle force in sickle cell patients, their local muscle fatigability was similar to that of the healthy subjects.
  
  
  CONCLUSIONS
  Sickle cell patients have normal resting muscle oxygen consumption and fatigability despite hemorheological alterations and, for SS patients only, reduced muscle microvascular oxygenation and increased microvascular blood flow. Two alternative mechanisms can be proposed for SS patients: 1) the increased muscle microvascular blood flow is a way to compensate for the lower muscle microvascular oxygenation to maintain muscle oxygen consumption to normal values or 2) the reduced microvascular oxygenation coupled with a normal resting muscle oxygen consumption could indicate that there is slight hypoxia within the muscle which is not sufficient to limit mitochondrial respiration but increases muscle microvascular blood flow.
authors.affiliation: Inserm 665, Université des Antilles et de la Guyane, Pointe-à-Pitre, Guadeloupe, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Waltz
authors.forename: Aurélien
authors.initials: A
authors.lastname: Pichon
authors.forename: Nathalie
authors.initials: N
authors.lastname: Lemonne
authors.forename: Danièle
authors.initials: D
authors.lastname: Mougenel
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Lalanne-Mistrih
authors.forename: Yann
authors.initials: Y
authors.lastname: Lamarre
authors.forename: Vanessa
authors.initials: V
authors.lastname: Tarer
authors.forename: Benoit
authors.initials: B
authors.lastname: Tressières
authors.forename: Maryse
authors.initials: M
authors.lastname: Etienne-Julan
authors.forename: Marie-Dominique
authors.initials: MD
authors.lastname: Hardy-Dessources
authors.forename: Olivier
authors.initials: O
authors.lastname: Hue
authors.forename: Philippe
authors.initials: P
authors.lastname: Connes
mesh_terms: D000328:Adult; D000755:Anemia, Sickle Cell / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D005542:Forearm / Q000098:blood supply; D005583:Fourier Analysis; D018056:Hemorheology / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D008297:Male; D055806:Microvessels / Q000378:metabolism* / Q000503:physiopathology; D015999:Multivariate Analysis; D018763:Muscle Fatigue / Q000502:physiology*; D009132:Muscles / Q000378:metabolism / Q000503:physiopathology*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D012039:Regional Blood Flow; D012146:Rest
chemical_list: D010100:Oxygen