Correlation of serum nicotinamide phosphoribosyl transferase with hypoxia and Framingham risk score in patients with obstructive sleep apnea-hypopnea syndrome

Background: Obstructive sleep apnea-hypopnea syndrome (OSAHS) is an independent risk factor for atherosclerosis (AS), but the mechanism is different from classical AS risk factors. Nicotinamide phosphoribosyltransferase (NAMPT) is involved in the pathophysiology of AS via multiple pathways, and its expression is closely related to hypoxia. The association of NAMPT with hypoxia and the risk of cardiovascular morbidity in the patients of OSAHS remains to be defined. Therefore, we carried out this study to investigate the association of NAM PT with hypoxia and the risk of early cardiovascular disease [based on the Framingham risk score (FRS)] in patients with OSAHS. Methods: A total of 82 patients diagnosed with OSAHS were enrolled in this cross-sectional survey design, along with 18 healthy controls who were age- and gender-matched. The general characteristic parameters including height and weight as well as biochemical parameters including blood glucose and lipid were collected from the subjects. The Framingham vascular risk score calculates the risk of developing vascular disease based on the above indicators. Polysomnography was performed in patients with OSAHS, and blood oxygen saturation and apnea-hypopnea index (AHI) were collected, and patients were grouped by disease extent by AHI. The serum NAMPT level of the research subjects was detected using an enzymelinked immunosorbent assay. Spearman correlation analysis and multiple linear regression to explore the independent correlations of hypoxia on serum NTAMPT activity in OSAHS patients. Results: Serum NAMPT level in patients with OSAHS increased with the severity of the disease. Correlation analysis showed that NAMPT was significantly positively correlated with FRS in patients with OSAHS (r=0.829, P<0.05). Multiple linear regression analysis with FRS as the outcome measure showed that NAMPT activity and minimum blood oxygen saturation were independent associated with the risk of developing cardiovascular disease (13=0.03, P=0.000; 13=-0.13, P=0.034). Univariate and multivariate regression analyses revealed that hypoxia was significantly associated with NAMPT levels in OSAHS patients, and the oxygen desaturation index (ODI) was independent associated with the expression of NAMPT activity (beta=4.09, P=0.000). Conclusions: In patients with OSAHS, hypoxia is independently associated with NTAMPT. NAMPT increases the risk of cardiovascular morbidity in this population may be influenced by hypoxia.