Is vagal nerve function impaired and its correlation to CD4+ T-cell populations altered in patients with neovascular age-related macular degeneration compared to healthy individuals?
Patients with neovascular age-related macular degeneration exhibit impaired vagal tone and an altered regulatory T-cell profile, suggesting a disrupted neuroimmune axis that may contribute to systemic inflammation.
Purpose: The purpose of this study was to investigate vagal nerve function and correlation to CD4+ T-cell population in patients with neovascular age-related macular degeneration (nvAMD) and healthy individuals. Methods: This study is a prospective case-control study including 36 patients with nvAMD and 40 healthy individuals. We measured the proxy of vagus nerve activity, the resting heart rate variability (HRV). Freshly sampled venous blood was prepared to measure CD4+ T-cell populations regulated by the vagal tone (regulatory T cells Tregs, recently thymic emigrant Tregs, naïve Tregs, and effector memory T cells). Results: Compared with healthy individuals, patients with nvAMD had significantly lower HRV (low frequency/high frequency LF/HR ratio, P = 0.037 and standard deviation SD ratio, P = 0.011), indicating impaired vagal function. HRV measures negatively correlated to the proportion of Tregs (square root of the mean squared difference of successive NN intervals RMSSD, P = 0.046) and memory T cells (RMSSD, P = 0.046) in healthy individuals, suggesting an intact regulatory capacity. These correlations were not found in patients with neovascular AMD, suggesting an impaired vagus nerve-regulatory T cell axis. Patients with nvAMD had significantly higher Tregs (P = 0.0005), naïve Tregs (P = 0.016), and recent thymic emigrant Tregs (P = 0.015). Conclusions: Vagal tone is impaired in patients with nvAMD which disharmonizes with increased Tregs in the systemic circulation. These altered regulators may be the key to increased systemic inflammation, present in patients with nvAMD.
Molbech et al. (Wed,) studied this question.