Leptin, Obestatin and Apelin levels in patients with obstructive sleep apnoea syndrome

BACKGROUND Recent studies suggest that adipose tissue hormones are involved in the pathogenesis of obstructive sleep apnoea syndrome (OSAS). The role of leptin, obestatin and apelin still needs to be established. MATERIAL/METHODS Ten patients with newly diagnosed OSAS (AHI >10/h and ESS >10 points) were enrolled in the study as well as ten healthy volunteers as controls. All underwent measurements for Leptin, Obestatin and Apelin in four hour intervals during diagnostic polysomnography for 24 h and the patients also three months after onset of CPAP treatment. Furthermore the HOMA-index and body composition were quantified. RESULTS Plasma apelin levels in the patients decreased under CPAP therapy, but showed no significant difference in patients and volunteers. We found a positive correlation to AHI, BMI in the therapy group at all observation points. Leptin plasma levels were higher in the patient group and decreased after onset of CPAP therapy. Leptin plasma levels were positively correlated to the BMI, min. 02 and AHI in the patient group before therapy. Plasma obestatin levels did not differ significantly in these three observation groups, but were partly correlated to AHI and weight in the newly diagnosed OSAS group. CONCLUSIONS In agreement with previous investigations, we could demonstrate a difference in leptin plasma levels between healthy volunteers and patients with newly diagnosed OSAS. Apelin decreases under CPAP therapy, but not significantly. Obestatin remains unchanged after onset of CPAP. We further found a linkage between leptin plasma levels and BMI, AHI and weight in the untreated patient group.