Renalase and hypertension—demographic and clinical correlates in obstructive sleep apnea

BACKGROUND: Renalase plays an important role in blood pressure regulation. Obstructive sleep apnea (OSA) is a common respiratory disorder associated with hypertension and cardiovascular complications. The aim of the study was to assess the relationship between sleep apnea and renalase concentration. MATERIAL AND METHODS: Adult patients (n = 113) were evaluated for OSA in a sleep laboratory using polysomnography. The respiratory events were scored according to the standards developed by the American Academy of Sleep Medicine. The blood renalase concentration was determined by the ELISA (enzyme-linked immunosorbent assay) test. RESULTS: OSA (AHI ≥ 5) was diagnosed in 71% (n = 80) of the studied population. Renalase concentration was statistically significantly lower in the group with moderate-to-severe OSA (AHI ≥ 15) compared with the group without OSA (AHI < 5) (139.56 ± 175.72 ng/ml vs. 230.97 ± 240.50 ng/ml, p = 0.042). We have found statistically significant negative correlation between renalase and AHI in hypertensives, but not in normotensives. The statistically significant negative correlation was observed between AHI and renalase in the whole studied group, in males, and in the group of age < 60 years old. There was not such a correlation in females and in the group > 60 years old. Based on the regression model, it was shown that lower renalase concentration, hypertension, higher BMI, and male gender are independently associated with higher AHI. CONCLUSIONS: There is a relationship between the blood renalase concentration and the severity of OSA, which may influence hypertension development in OSA.