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


METHODS
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 submaximal progressive treadmill exercise (10 min at 30 and 50%, and 20 min at 75% of V O2max), allowing for maximal fat-oxidation rate and blood-oxidative stress determinations. They were compared with 15 healthy control participants (C).


RESULTS
V O2max 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+/-134.8 mg/min in C; P<0.01), but it was in the normal range.


CONCLUSIONS
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.
Flore
Patrice
P
Grenoble 1 University (Joseph Fourier) (UFRAPS and UFR Santé), IFR 1, Research on Exercise and Health Laboratory, South Hospital, Grenoble University Hospital, Grenoble cedex, France. PFlore@chu-grenoble.fr
Bricout
Véronique-A
VA
van Biesen
Debbie
D
Guinot
Michel
M
Laporte
François
F
Pépin
Jean-Louis
JL
Eberhard
Yves
Y
Favre-Juvin
Anne
A
Wuyam
Bernard
B
van de Vliet
Peter
P
Faure
Patrice
P
D000328:Adult; D000704:Analysis of Variance; D001795:Blood Pressure Determination; D016022:Case-Control Studies; D004314:Down Syndrome / Q000378:metabolism* / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D018384:Oxidative Stress; D017286:Polysomnography; D012146:Rest