Cognitive Physiology in Healthy Young Adults: Links to Ciliary Neurotrophic Factor and Retinal Biomarkers

Background: Ciliary neurotrophic factor (CNTF) is a neurotrophic cytokine involved in neuronal survival, synaptic plasticity, and retinal ganglion cell health, and it correlates with different stages of cognitive impairment. Mild cognitive impairment (MCI) is difficult to diagnose, as these patients perform normally on standardized cognitive tests. It is important to diagnose patients with MCI early to prevent its progression and to maintain their quality of life. Alterations in retinal morphology mirror central nervous system pathology, including cognitive impairment. Objective: This cross-sectional study investigates the association between retinal structural changes and plasma CNTF levels and assesses their possible clinical value for screening early cognitive impairment. Methods: Retinal morphology was assessed by optical coherence tomography (OCT), and plasma CNTF was measured by enzyme-linked immunosorbent assay (ELISA) in 69 healthy participants. We correlated retinal biomarkers and CNTF levels with cognitive function as measured by the Montreal Cognitive Assessment (MoCA). Results: CNTF levels were significantly higher in the low MoCA group (median = 287.6, IQR: 235.90–359.7) compared to the normal cognition group (median = 185.90, IQR: 162.1–277.5) (p < 0.001). Average central thickness and retinal nerve fiber layer (RNFL) were positively associated with CNTF (p < 0.05). Conclusions: Our results indicate that CNTF is negatively associated with cognition and positively correlated with RNFL and average central thickness. Screening for MCI with non-invasive OCT imaging and plasma CNTF may aid in the early detection of cognitive impairment. Future pharmacological interventions with CNTF analogs may preserve or even restore cognitive function.