Background: Neuroglobin (Ngb) is highly expressed in the suprachiasmatic nucleus, and can regulate Per1 gene expression. It is still not known whether Ngb also influences Cryptochrome (Cry). Cry is implicated in hypertension and primary aldosteronism (PA) in mice. There is a strong correlation between Obstructive Sleep Apnea (OSA) and PA. We propose to prove that Ngb and Cry play a role in OSA with PA.
Methods: Subjects were recruited consecutively from residents of Jakarta, Indonesia; subjects aged 30-65 years with moderate to severe OSA and hypertension were included in the study. OSA was diagnosed using an unattended type 2 portable monitor (Alice Pdx), hypertension was diagnosed when morning blood pressure exceeded 140/90 mmHg or when taking anti-hypertensive drugs. Serum concentration of aldosterone, renin, Cry1, Cry2 and Ngb protein were determined using ELISA method. Primary aldosteronism (PA) was defined as ARR ≥20.
Results: Forty subjects were recruited, 26 male and 14 female, median age 52.5 years, BMI 27.46 kg/m2, and AHI 34.8 times/hour. We found 16 subjects with PA and 24 non PA. Cry1 and Cry2 did not correlate with ARR in PA and non PA groups. Ngb correlated positively with Cry1 (Spearman's rho = 0.455, p = 0.038) but not Cry2 in PA patients. Cry1 concentration decreased in severe hypoxia.
Conclusions: Ngb correlates with Cry1 in OSA with PA. There is no correlation between Cry1 or Cry2 with PA.