Chitinase-3-Like 1 Protein (CHI3L1) Levels in Patients With Cognitive Deficits and Movement Disorders: Comparison With Other Biomarkers.

INTRODUCTION: Chitinase-3-like protein 1 (CHI3L1) is a glycoprotein implicated in various neurological conditions. It is associated with neuroinflammation and tissue remodeling. The study aimed to validate the reference interval (RI) of serum (S) CHI3L1 in a control group, to correlate S CHI3L1 values with other biomarkers of neurodegenerative damage, and to estimate the diagnostic accuracy of S CHI3L1. METHODS: Samples from 108 healthy volunteers were used to estimate the S CHI3L1 RI. For the comparison, we used cerebrospinal fluid (CSF) and serum (S) samples from 121 patients with cognitive disorders, and cognitive deterioration was assessed using the Mini-Mental State Examination (MMSE). ELISA assays were used to determine the S CHI3L1, CSF, and S neurofilament light chain (NfL) levels; CSF and plasma β-amyloid peptide(42); CSF and plasma β-amyloid peptide(40); CSF total tau protein; CSF phosphorylated tau protein; and CSF alpha-synuclein. RESULTS: The estimated RI of S CHI3L1 was 14.44 to 63.11 µg/L. The cut-off value of S CHI3L1 was 34.37 µg/L. ROC analysis showed that S CHI3L1 has 81.4% sensitivity and 76.9% specificity. We found a moderate Spearman's rank correlation coefficient between the S CHI3L1 and age (r(S )= 0.486; p < 0.001) and between S CHI3L1 and S NfL (r(S) = 0.489; p < 0.001) in all groups. The Kruskal-Wallis test showed a significant overall difference in S CHI3L1 among diagnostic groups (p = 0.013). S CHI3L1 and CSF NfL had statistically significant effects on MMSE values (multiple R(2) was 0.431). CONCLUSIONS: Our results suggest that S CHI3L1 reflects the severity of cognitive deficits assessed by MMSE. It can be used as a supportive biomarker in neurodegenerative diseases.