Associations of plasma CDR1as with memory function and mild cognitive impairment in type 2 diabetes: the mediating effect of α-synuclein

Antisense to the cerebellar degeneration-related protein 1 transcript (CDR1as) and α-synuclein (α-Syn) are involved in the pathophysiology of type 2 diabetes mellitus (T2DM) and mild cognitive impairment (MCI). CDR1as affects α-Syn gene expression, but further investigation is required to elucidate the relationship and potential mechanisms. Our objective was to examine the correlation between plasma CDR1as and MCI in T2DM patients, as well as the mediating role of α-Syn. The 579 recruited T2DM subjects were divided into 273 individuals with MCI and 306 controls with normal cognition. Plasma CDR1as and α-Syn levels were measured, and neuropsychological assessment data were analyzed. We evaluated the associations of CDR1as and α-Syn with MCI and memory function using multivariable regression analyses and restricted cubic spline (RCS) functions. Moreover, we examined the mediating effect of α-Syn by mediation analysis. After adjusting for confounders, CDR1as exhibited a protective association with MCI and memory function (OR = 0.45, 95 % confidence interval [CI]: 0.31–0.65; β = 0.29, 95 % CI: 0.17–0.40). α-Syn showed an inverse association with MCI and a positive correlation with memory function. CDR1as was positively associated with α-Syn. Additionally, mediation analysis revealed that the impact of CDR1as on MCI and memory function was partially mediated by α-Syn, with mediation effects of 34.03 % and 31.71 %, respectively. Elevated plasma CDR1as levels are associated with a protective effect against MCI, especially regarding memory function, and α-Syn may partially mediate this association.