Oxidative stress and metabolism at rest and during exercise in persons with Down syndrome

  1. Patrice Florea,b⇓
  2. Véronique-A Bricouta,b
  3. Debbie van Biesena,g
  4. Michel Guinotb
  5. François Laportec
  6. Jean-Louis Pépind,e
  7. Yves Eberhardf
  8. Anne Favre-Juvinb
  9. Bernard Wuyama,b
  10. Peter van de Vlietg
  11. Patrice Faurec,e
  1. a Grenoble 1 University (Joseph Fourier) (UFRAPS and UFR Santé), IFR 1, Research on Exercise and Health Laboratory, South Hospital, Grenoble University Hospital
  2. b Grenoble University Hospital, Medical Unit of Sport Medicine, Traumatology and of Clinical Research on Exercise, Physiology, Sleep and Exercise Clinic, Physiology – Reeducation Center, South Hospital
  3. c Integrated Biology Department, Grenoble University Hospital
  4. d Grenoble University Hospital, Sleep Laboratory, Physiology, Sleep and Exercise Clinic, Physiology – Reeducation Center
  5. e INSERM, ERI17, Université Grenoble 1 (Joseph Fourier), IFR 1, Laboratoire HP2
  6. f Grenoble 1 University (Joseph Fourier), IFR1, Fundamental and Applied Biology Laboratory, INSERM E221, Grenoble cedex, France
  7. g Department of Rehabilitation Sciences, Katholieke Universiteit Leuven, Belgium
  1. Correspondence to Patrice Flore, UF de Recherche Clinique sur l’Exercice Musculaire, Hôpital Sud, BP185, 38042 Grenoble Cedex 09, France Tel: +33 4 76 76 54 94; fax: +33 4 76 76 89 21; e-mail: PFlore@chu-grenoble.fr

Abstract

Background Down syndrome (DS) is a risk factor for metabolic syndrome and cardiovascular disease. The greater oxidative stress described in DS can increase this risk owing to its potential deleterious effects on insulin sensitivity. We hypothesized that metabolic syndrome or its markers, at rest and during exercise, are more pronounced in young adults with DS.

Design The study design is that of a controlled study.

Methods Thirteen physically active young adults with DS, after overnight polysomnography, plasma-lipid profile, and insulin-resistance [Homeostasis Model Assessment Insulin Resistance (HOMA-IR)] assessments, underwent a sub-maximal progressive treadmill exercise (10 min at 30 and 50%, and 20 min at 75% of Vo2 max), allowing for maximal fat-oxidation rate and blood-oxidative stress determinations. They were compared with 15 healthy control participants (C).

Results Vo2 max of DS participants was lower than that of C (60.8 ±2.4 versus 44.4 ± 3.3 ml/kg/min; P < 0.001) but was close to the predicted value (95 ±6%). In DS participants, as expected, oxidative stress was greater than in C (+ 15%; P < 0.001) at rest and all through the exercise protocol. Although a greater fat mass (DS: 19.9 ±1.3%; C: 13.5 ±0.9%; P < 0.001), and a lower insulin sensitivity (HOMA-IR in DS: 1.09±0.16; in C: 0.64±0.13; P < 0.05) was observed for DS participants, a metabolic syndrome could not be shown. Maximal fat-oxidation rate was lower in DS participants (394.2 ±69.9 versus 486.1 ±134.8mg/min in C; P < 0.01), but it was in the normal range.

Conclusion Despite greater oxidative stress and lower insulin sensitivity, the DS group involved in our study did not display clear metabolic abnormalities. The young age and lifestyle of this group might, partially, have accounted for this apparently healthy metabolic status.

 

  • Received December 30, 2006.
  • Accepted September 28, 2007.

 

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