Abstract:

Objective   To explore the changes of plasma  beta-endorphin(β-EP), neuropeptide Y(NPY) and Ghrelin levels in the patients with obstructive sleep apnea hypopnea syndrom (OSAHS) and their correlations with PSG indicators, and observe the changes of  the three peptides after CPAP treatment. Methods   There were three groups, including 32 cases of obese OSAHS patients (OSAHS group), 26 cases of obese adult without OSAHS (simple obesity group) and 27 normal healthy adults (normal controls group). Polysomnography (PSG) was performed in OSAHS group and simple obesity group. The concentrations of plasmaβ-EP, NPY, Ghrelin were determined by enzyme-linked immunosorbent(ELISA). Results   Plasma β-EP concentration in OSAHS group  was significantly higher than those in simple obesity group and normal control group (P<0.01), and there was positive correlations betweenβ-EP and sleep apnea hypopnea index (AHI) or the longest sleep apnoea time (LAT) (P<0.05). There was negative correlation betweenβ-EP and lowest oxygen saturation (LSaO2) or mean oxygen saturation (MSaO2)( P=0.016, 0.000 respectively). Plasma NPY concentration in OSAHS group was significantly higher than those in simple obesity group  (P<0.05) and normal control group (P<0.01). Plasma NPY level in the OSAHS group was correlated positively with BMI, AHI, arousal index (MAI), or Epworth Sleepiness Scale (ESS score)   (P<0.01). NPY changes in simple  obesity group were positively correlated with BMI (P<0.05). Plasma Ghrelin concentration in OSAHS group was lower than those in simple obesity group and normal control group (P<0.01).  No significant correlation was found with PSG indicators. After continuous positive airway pressure (CPAP) treatment for 3 months, β-EP, NPY levels were decreased (P<0.05) and Ghrelin levels rose higher than that before the treatment without significant difference. Conclusion   In OSAHS group, the plasma β-EP, NPY levels were increased, and Ghrelin levels were decreased due to repeated apnea and hypopnea. In addition to obesity, recurrent apnea and arousal may play a more important role for the changes of NPY levels . Elevated NPY plays a catalytic role on the daytime sleepiness in the patients with OSAHS. CPAP treatment for 3 months can reduce β-EP and NPY levels to some extent, but exert limited role for  Ghrelin.

Key words: Obstructive sleep apnea hypopnea syndrom; βendorphin ；Neuropeptide Y; Ghrelin；Continuous positive airway pressure