Objective: This study try to assess the endothelial function in vivo using flow mediated dilatation (FMD) and several biomarkers of endothelium formation/restoration and damage in patients with obstructive sleep apnoea (OSA) syndrome at baseline and after three months with CPAP therapy.
Design and method: Observational study, before and after CPAP therapy. We studied 30 patients with apnoea/hypopnoea index > 15/h that were compared with themselves after three months of CPAP therapy. Flow mediated dilatation (FMD) was assessed non-invasively by in vivo using the Laser-Doppler flowmetry. Circulating cell free DNA (cf-DNA) and microparticles (MPs) were measured as markers of endothelial damage and the vascular endothelial growth factor (VEGF) was determined as a marker of endothelial restoration process.
Results: After three month with CPAP, FMD significantly increased (1072.26 +/- 483.21 vs. 1604.38 +/- 915.69 PU, p < 0.005), and cf-DNA and MPs significantly decreased (respectively: 187.93 +/- 115.81 vs. 121.28 +/- 78.98 pg/ml, p < 0.01 and 69.60 +/- 62.60 vs. 39.82 +/- 22.14 U/[mu]L, p < 0.05). Finally, VEGF increased (585.02 +/- 246.06 vs. 641.11 +/- 212.69 pg/ml, p < 0.05). These changes were higher in patients with more severe disease. There was a relationship between markers of damage (r = -0.53, p < 0.005) but not among markers of damage and restoration, thus suggesting that both types of markers should be measured together.
Conclusions: CPAP therapy improves FMD. This improvement may be related to an increase of endothelial restoration process and a decrease of endothelial damage.
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