Tau protein and brain-derived neurotrophic factor levels in blood serum of patients with obstructive sleep apnea (pilot study)

Background. Tau protein is considered one of the indicators of risk or progression of neurodegenerative processes. Brain-derived neurotrophic factor (BDNF), on the contrary, is one of the modulators of neuronal survival and differentiation, which prevents their damage. Obstructive sleep apnea (OSA) is an independent risk factor for neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease due to chronic hypoxia, sleep fragmentation, systemic inflammation, and oxidative stress. At the moment, not much work has been done on the relationship between the content of tau protein and BDNF in the blood of patients with OSA, but the available data also presents contradictory results that do not fully disclose this relationship.

Objective. To evaluate the content of tau protein and brain-derived neurotrophic factor in patients with severe OSA.

Materials and methods. We performed a cross-sectional comparative study in 23 patients (16 men; 7 women), with an average age of 41 [37;43] years with a severe form of OSA. The diagnosis was confirmed by standard polysomnography. The control group consisted of 17 people (10 men; 7 women), of the “copy – pair” type, with an average age of 37 [21;44.5] years. The levels of tau protein and BDNF were determined by enzyme immunoassay. The data is presented as the median, upper and lower percentiles. Intergroup comparisons were performed using the Mann – Whitney U-test.

Results. The polysomnography (PSG) results obtained by us demonstrate the characteristic breathing pattern and features of the macrostructure of sleep in patients with OSA. The assessment of the content of tau protein and BDNF in blood plasma demonstrates a statistically significant increase in the content of tau protein and BDNF in patients with CCA compared with the indicators of the control group.

Conclusion. The results obtained suggest the presence of an adaptive profile in the processes of neuroplasticity against the background of the incipient processes of neurodegeneration in patients with OSA.

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