Accumulating data suggest that various neurologic manifestations are reported in critically-ill COVID-19 patients. Although low testosterone levels were associated with poor outcomes, the relationship between testosterone levels and indices of brain injury are still poorly understood. Therefore, we aimed to explore whether testosterone levels are associated with glial fibrillary acidic protein (GFAP) and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), biomarkers of brain injury, in patients with a severe form of COVID-19. The present study was conducted on 65 male patients aged 18−65 with severe COVID-19. Blood samples were collected at three time points: upon admission to ICU, 7 days after, and 14 days after. In patients with neurological sequels (n = 20), UCH-L1 serum concentrations at admission were markedly higher than in patients without them (240.0 (155.4−366.4) vs. 146.4 (92.5−243.9) pg/mL, p = 0.022). GFAP concentrations on admission did not differ between the groups (32.2 (24.2−40.1) vs. 29.8 (21.8−39.4) pg/mL, p = 0.372). Unlike GFAP, UCH-L1 serum concentrations exhibited a negative correlation with serum testosterone in all three time points (r = −0.452, p < 0.001; r = −0.430, p < 0.001 and r = −0.476, p = 0.001, respectively). The present study suggests that the traumatic brain injury biomarker UCH-L1 may be associated with neurological impairments seen in severe COVID-19. Moreover, a negative correlation between UCH-L1 and serum testosterone concentrations implies that testosterone may have a role in the development of neurological sequels in critically-ill COVID-19 patients.
Keywords: COVID-19; GFAP; SARS-CoV-2; UCH-L1; neurovascular damage; testosterone.