Development of an improved ELISA method based on gold nanoparticles to evaluate the correlation of serum occludin and zonula occludin-1 (ZO-1) levels with cognitive impairment in elderly patients with acute cerebral infarction

The present study evaluated an improved Enzyme linked immunosorbent assay (ELISA) method based on gold nanoparticles by investigating the correlations of measured serum occludin and zonula occludin-1 (ZO-1) levels with cognitive impairment in elderly patients with acute cerebral infarction (ACI). The present study comprised a total of 98 patients with ACI that were divided into patients with normal cognitive function (normal group) and patients with cognitive impairment (PSCI group) according to mini-mental state examination (MMSE) scores. Serum levels of triglycerides, total cholesterol, and low-density lipoprotein were measured using an automatic biochemical analyzer. Serum occludin and ZO-1 levels in both groups were measured using a modified ELISA assay with nanogold particles. Neurological function in elderly patients with ACI was assessed using the National Institutes of Health Stroke Scale (NIHSS) score. Pearson’s correlation coefficient was calculated for the correlations between serum occludin levels, serum ZO-1 levels, and cognitive impairment in elderly patients with ACI. Receiver operating characteristics (ROC) curves were used to analyze the diagnostic value of serum occludin and ZO-1 levels in detecting cognitive impairment in elderly patients with ACI. Logistic regression analysis was used to identify factors associated with cognitive impairment in elderly patients with ACI. In the PSCI group, a significantly higher proportion of patients had hypertension, coronary heart disease, and diabetes compared to the normal group. Serum occludin and ZO-1 levels were significantly lower in the PSCI group compared to the normal group ( P <0.05). Serum occludin and ZO-1 levels in elderly patients with ACI were negatively associated with NIHSS score ( P <0.05). Receiver operating characteristic analysis demonstrated that the area under the curve (AUC) of serum occludin and ZO-1 in detecting cognitive impairment in elderly patients with ACI was 0.926 and 0.824 respectively, with a combined AUC of 0.945 indicating a synergistic effect in detecting cognitive impairment. Logistic regression analysis showed that hypertension, diabetes, coronary heart disease, and lower serum occludin, and ZO-1 levels were all independent risk factors for cognitive impairment in elderly patients with ACI. Lower serum levels of occludin and ZO-1 level had diagnostic value in detecting cognitive impairment in elderly patients with ACI and may have utility as an auxiliary diagnostic index for cognitive dysfunction in patients with ACI.