Abstract:Objective To analyze the serum levels of long non-coding RNAs (lncRNAs) metastasis associated lung adenocarcinoma transcript 1 (MALAT1) and nuclear paraspeckle assembly transcript 1 (NEAT1) in patients with Alzheimer's disease (AD) and to explore whether they are involved in the inflammatory response and cognitive impairment in AD.Methods A total of 93 patients with AD admitted to our hospital from January 2018 to January 2021 were selected as the AD group, and another 54 healthy individuals undergoing physical examination during the same period were selected as the control group. Serum levels of lncRNAs MALAT1 and NEAT1 were measured by qRT-PCR, and serum levels of high-sensitivity C-reactive protein (hs-CRP), interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) were measured by ELISA. The cognitive function of patients was assessed by the Mini-Mental State Examination (MMSE). Pearson or Spearman method was used to analyze the correlations between serum levels of lncRNAs MALAT1 and NEAT1 and the disease duration, MMSE scores and inflammatory factors in AD patients. ROC curves were used to analyze the diagnostic values of serum inflammatory indicators and expressions of lncRNAs MALAT1 and NEAT1 for AD.Results The serum expression of MALAT1 (Z = -8.381, P = 0.000) and MMSE score (Z = -9.904, P = 0.000) in AD group were lower than those in control group, while the serum expression of NEAT1 (t = 10.479, P = 0.000) in AD group was higher than that in the control group. The serum levels of hs-CRP (t = 14.575, P = 0.000), IL-1β (t = 8.503, P = 0.000), IL-6 (t = 10.739, P = 0.000), and TNF-α (t = 6.522, P = 0.000) in AD group were higher than those in control group (P < 0.05). Pearson or Spearman correlation analysis showed that the expression of serum MALAT1 was positively correlated with MMSE score (rs = 0.587, P = 0.000), and negatively correlated with hs-CRP (rs = -0.522, P = 0.000), IL-1β (rs = -0.601, P = 0.000), IL-6 (rs = -0.574, P = 0.000), and TNF-α levels (rs = -0.577, P =0.000) in AD patients. The expression of NEAT1 was negatively correlated with MMSE score (rs = -0.593, P = 0.000), and positively correlated with the levels of hs-CRP (r = 0.487, P = 0.000), IL-1β (r = 0.588, P = 0.000), IL-6 (rs = 0.611, P = 0.000) and TNF-α (r = 0.573, P = 0.000). The ROC curve analysis showed that the AUC of serum MALAT1 for the diagnosis of AD was 0.915 (95% CI: 0.858, 0.955), and the optimal cut-off value was 0.98, with the corresponding sensitivity being 94.62% (95% CI: 87.92, 98.22) and the specificity being 81.48% (95% CI: 68.61, 90.70). The AUC of serum NEAT1 for the diagnosis of AD was 0.858 (95% CI: 0.791, 0.910), and the optimal cut-off value was 2.37, with the corresponding sensitivity being 90.32% (95% CI: 82.45, 95.52) and the specificity being 72.22% (95% CI: 58.44, 83.57).Conclusions The low expression of lncRNA MALAT1 and the high expression of lncRNA NEAT1 in the serum may be associated with the inflammatory response and cognitive impairment in AD patients. Thus, they can be established as potential diagnostic markers for AD.