Aging and the effects of chronic intermittent hypoxia caused by obstructive sleep apnea

Background: Obstructive sleep apnea (OSA) is one of the most common sleep disorders and is characterized by intermittent hypoxia (IH) and sleep fragmentation. It is known that aging is a risk factor for OSA development, however, the potential influences of OSA on the aging have not been widely investigated. Objective: In this study, we evaluated the impact of intermittent hypoxia (IH) on elderly mouse model. Results: The mice were randomly divided into four groups: young + room air (RA) (YC), elderly + RA (EC), young + IH (YI), and elderly + IH (EI). Mice (C57BL/6, female) were exposed to RA or IH (20 cycles/h, FiO₂ nadir 7 ± 0.5%, 8 h/day) for 4 weeks. The mice were sacrificed at day 28. The EI group showed a trend of more severe inflammation, fibrosis, and oxidative stress compared to the other groups, including the YC group. Inflammatory cytokines such as IL12p70, TNF, IFN-γ, IL-10, IL-6 from serum increased significantly in the EI group compared to the other groups. In addition, the EI group showed significantly more increased leukocyte count compared to room air-treated groups and a trend of more inflammatory cytokines in the bronchoalveolar (BAL) fluid compared to other groups. In neuromuscular coordination test, the elderly mouse showed a significant decrease compared to the young mouse, particularly in the elderly mouse with IH-induced sleep apnea. Conclusion: This study shows the possible harmful impact of IH on aging in a mouse model. This result suggests that older patients with OSA may be more of a concern. Further research into the mechanisms underlying the effects of IH on systemic and lung infection in aging is needed.