Decreased Plasma Level of Lipoprotein Lipase Predicted Verbal Disfluency in Chinese Type 2 Diabetes Mellitus Patients with Early Cognitive Deficits

Background: Lipoprotein Lipase (LPL) is the rate-limiting enzyme catalyzing the hydrolysis of triglycerides and contributes to the amyloid-β formation, which shows promise as a pathological factor of cognitive decline in Type 2 Diabetes Mellitus (T2DM). This study aimed to investigate the pathogenetic roles of LPL and rs328 polymorphism in Mild Cognitive Impairment (MCI) in patients with T2DM. Methods: Chinese patients with T2DM were recruited and divided into two groups based on the Montreal Cognitive Assessment score. Demographic data were collected, LPL was measured and neuropsychological test results were examined. Results: Seventy-nine patients with diabetes and MCI had significantly decreased plasma LPL levels (p = 0.007) when compared with health-cognition controls (n = 91). Correlation analysis revealed that LPL was positively correlated with clock drawing test (r = 0.158, p = 0.043) and logical memory test (r = 0.162, p = 0.037), while lipoprotein a (r = -0.214, p = 0.006) was inversely associated with LPL. Logistic regression analysis further demonstrated that LPL concentration was an independent factor for diabetic MCI (p = 0.036). No significant differences were observed in the distributions of rs328 variants between patients with MCI and the controls. Moreover, no remarkable association was found among plasma LPL levels, cognitive performances, and lipid levels between the genotypic subgroups. The trail making test A was increased in the GC group when compared with the CC genotype in the control group. Conclusion: Decreased plasma level of LPL could probably predict early cognitive deficits, especially verbal disfluency.