Objective To investigate the relationships of serum levels of human fractalkine (CX3CL1) and chitinase-3-like protein 1 (YKL-40) with early cognitive impairment in elderly patients with Alzheimer's disease (AD).
Methods A total of 110 AD patients in the Second Affiliated Hospital of Xinxiang Medical University from February 2021 to December 2023 were selected as AD group, and 50 healthy individuals with physical examination during the same period were selected as control group. Clinical materials and serum levels of CX3CL1 and YKL-40 were compared between the two groups, and multivariate Logistic regression models were used to analyze the influencing factors of cognitive impairment in AD patients. Based on the Mini-Mental State Examination (MMSE) score, the 110 AD patients were divided into mild cognitive impairment group (n=47), moderate cognitive impairment group (n=36), and severe cognitive impairment group (n=27). Spearman correlation analysis was performed to explore the relationships of serum CX3CL1 and YKL-40 with MMSE score, Addenbrooke's Cognitive Examination-Ⅲ (ACE-Ⅲ) score, and Montreal Cognitive Assessment (MoCA) score.
Results The AD group had higher proportions of patients aged over 80 years, with an education level of primary school or below, smoking history, alcohol consumption history, diabetes mellitus, hypertension, AD family history, and living alone as well as higher serum levels of CX3CL1 and YKL-40 compared to the control group; conversely, the AD group had a lower proportion of patients engaging in no physical exercise/labor, and lower MMSE, ACE-Ⅲ, and MoCA scores, with significant between-group differences (P < 0.05). Advanced age, diabetes mellitus, and high serum levels of CX3CL1 and YKL-40 were independent risk factors for cognitive impairment in AD patients (P < 0.05), while an education level of college or above was a protective factor (P < 0.05). Compared with the mild cognitive impairment group, the moderate and severe cognitive impairment groups had higher serum levels of CX3CL1 and YKL-40, and the severe cognitive impairment group had higher serum levels of CX3CL1 and YKL-40 than the moderate group, with significant between-group differences (P < 0.05). Spearman correlation analysis revealed that serum CX3CL1 and YKL-40 were negatively correlated with MMSE, ACE-Ⅲ, and MoCA scores (P < 0.05).
Conclusion Serum CX3CL1 and YKL-40 are highly expressed in elderly AD patients, and are closely related to early cognitive impairment in elderly AD patients.