Correlation between Aβ(1–42), Dnmt3a2, urinary AD7c-NTP and cognitive dysfunction in first-episode and recurrent MDD: A case–control study

BACKGROUND AND AIM: Major depressive disorder (MDD) is one of the most prevalent mental illnesses worldwide and involves cognitive dysfunction that may negatively impact clinical and social outcomes. Previous studies have suggested that beta-amyloid peptide (Aβ(1–42)), DNA methyltransferase (Dnmt3a2), and urinary Alzheimer-associated neuronal thread protein (AD7c-NTP) are associated with cognitive impairment. However, there are no relevant studies in MDD. The aim of this study was to assess the correlation between serum Aβ(1–42), Dnmt3a2, and urinary AD7c-NTP and cognitive dysfunction in MDD. MATERIALS AND METHODS: A total of 59 eligible patients were included in the study, including 29 patients with first-episode MDD (FEDs) and 30 patients with recurrent MDD (RMDDs), and 30 matched healthy controls (HCs) were selected. Participants’ cognitive functioning was evaluated using the MATRICS consensus cognitive battery (MCCB). The enzyme-linked immunosorbent assay (ELISA) method was used to measure the concentrations of the three proteins. Statistical analysis was completed using Statistical Package for the Social Sciences (SPSS) 20.0. The statistical significance was set as P < 0.05. RESULTS: Serum Dnmt3a2 and urinary AD7c-NTP showed significant differences among the three groups (both P < 0.001), but there were no significant differences in Aβ(1–42) levels. Upon examining the results of cognitive testing, we found that serum Aβ(1–42) was negatively associated with working memory scores in RMDDs (P = 0.020), but Dnmt3a2 was positively associated with working memory and verbal learning scores in the same cohort (P = 0.012 and P = 0.037, respectively). In contrast, urinary AD7c-NTP was negatively correlated with verbal learning scores in FEDs (P = 0.013). CONCLUSIONS: Serum Dnmt3a2 and Aβ(1–42) levels may be associated with cognitive impairment in RMDDs and may act as potential biomarkers of cognitive impairment. Although urinary AD7c-NTP was closely related to cognitive dysfunction in FEDs, this relationship did not hold in RMDDs.