The Effect Of Ectopic Accumulation Of Lipid And Leptin On The Pathogenesis Of OSAHS

Objective: To study the effct of ectopic accumulation of lipid and leptin on the pathogenesis and development of OSAHS.Methods: Thirty-eight cases were intermittently selected from the patients in hospital and devided into two groups. Each group had 19 cases. The test group were OSAHS patients, including 17 males and 2 females, ranging 26-47 years (35.11±5.92). All the patients were diagnosed according to the criteria in the Chinese Journal of Otolaryngology in December of 2002, and the cases caused by non-obesity factors or accompanied severe complications, such as hypertensive crisis, heart failure, were eliminated. The control group had 11 males and 8 females, raging 18-45 years (31.32±6.27), and the majority suffered chronic tonsillitis. The age of two groups showed no distinctive difference (P>0.05). The tissue sample was gotten by surgery, and the plasma sample was venous blood collected on empty stomach at early morning. HE staining, Youhong-O lipid staining, and electron microscope were used to observe the pathologic characteristic of the pharyngeal tissue, especially the ectopic accumulation of lipid. The immunohistochemical method of SABC was adopted to investigate the expression of leptin and its functional receptor (Ob-Rb) in the pharyngeal tissue, and the result was semi-quantitative analysed by RT-PCR. The level of lipid and leptin in plasma was tested by biochemical and radio-immunity methods respectively. The statistic methods were t-test and the correlation analysis. Results: There existed obvious fatty infiltration in the pharyngeal tissue of OSAHS patients. The regulated arrangement and continuity of the muscle fibers and the elastic fibers were destroyed, and the type and modality of the minor salivary glands were changed. The ultrastructure showed the corresponding changes and the cellular anoxic changes.In both of two groups, the positive expression of leptin and Ob-Rb located at the mucous layer, the wall of the small vessels and the edge of the minor salivary glands. The image and semi-quantitative analysis didn't show obvious difference between the two groups (P>0.05).The TC, TG, LDL and leptin level in plasma of OSAHS patients was higher than that of the control group (t=5.591,5.268,2.280,3.493,P<0.05), and significantly correlated with AHI (r=0.770,0.797,0.639,0.854,P<0.05). The HDL level was lower than the control group (t=-3.535,P<0.05), but the ApoB level had no difference from the control group (t=-3.535,P>0.05), and both of them had no correlation with AHI (r=-0.119,P>0.05;r=-0.109,P>0.05).Conclusion: Fatty infiltration in the pharyngeal tissue of OSAHS patients may lead the pharyngeal airway to sink during sleep.The epithelial cells of mucosa, endothelial cells of small vessels and glandular cells of minor salivary glands can produce leptin potentially. Leptin existing with its functional receptor shows the peripheral action of leptin. The positive expression of both has no significant difference from the control group, which may explain the ectopic accumulation of lipid. Contrarily, this can also show leptin is not correlated with the important mechanism influencing the occurrence and development of OSAHS.The OSAHS patients have disordered lipid metabolism, which significantly correlated with the severity of OSAHS. But it may not be the determinant factors of the pathogenesis.Endogenous hyperleptinmia characterizing OSAHS patients may be the protective response to the respiratory disturbance and the disordered lipid metabolism, also associated with the continuous hypersympathetic activity. The level of leptin in plasma has positive correlation with the severity of OSAHS.