According to a recent study, hypoxia associated with episodes of upper airway obstruction in patients with obstructive sleep apnea syndrome may increase the levels of α‐synuclein in the blood and thus may contribute to the development of Parkinson disease.
PD is a disease that primarily affects the motor system of the middle-aged and elderly population, although it can also contribute to sleep problems and present with neuropsychiatric symptoms. The disease also seems to be associated with the overproduction of α‐synuclein, which when clumped together forms dangerous Lewy bodies that attack and eventually kill brain cells. Prior research has identified OSAS as a risk factor for PD onset, and hypoxia may have contributed to this finding. Investigators of a recently published study sought to identify the association between α‐synuclein levels and hypoxia in patients with OSAS.
From September to December 2014, the study recruited 42 patients with OSAS to the intervention group and 46 patients with snoring to the control group. Among the participants in the intervention group, 8 patients had mild OSAS, 16 had a moderate form of the disease, and 18 experienced a severe form of the disease. The levels of total of total and phosphorylated α‐synuclein in the patients’ blood plasma were measured by enzyme-linked immunosorbent assay, and the results found that patients with OSAS had significantly higher levels of both total (37.68 ng/mL vs 21.08 ng/mL) and phosphorylated (26.87 ng/mL vs 14.61 ng/mL) α-synuclein in their plasma compared with controls.
However, the levels of both total and phosphorylated α‐synuclein were negatively correlated with the lowest and mean oxyhemoglobin saturations.
“In summary, the present study found that increased α‐synuclein levels in the plasma are correlated with the degree of hypoxia in OSAS, indicating that chronic hypoxia caused by OSAS may be involved in the pathogenesis of PD,” wrote the authors. In terms of future studies, researchers recommend conducting prospective studies with larger sample sizes in order to explore the clinical significance of elevated plasma α‐synuclein levels in patients with OSAS for predicting the risk of developing into PD.
Sun HL, Sun BL, Chen DW, et al. Plasma α‐synuclein levels are increased in patients with obstructive sleep apnea syndrome [published online March 12, 2019]. Ann Clin Transl Neurol. doi: 10.1002/acn3.756.