Fig. 3

Identification of the expression and structure of the cystatin F protein in the plasma of AD patients and analysis of its correlation with AD clinical manifestations. A Western blot analysis of the expression and structure of the cystatin F protein in plasma from patients with AD (n = 6) and controls (n = 6) by using a nondenaturing gel. The total protein in the plasma was stained with CBB as an internal control. B The structure of cystatin F in human plasma was determined by western blot assay, and DTT was added to the sample to reduce the dimers to the monomers. C ELISA analysis of secreted cystatin F levels in plasma from patients with AD (n = 45) and controls (n = 40). D ELISA analysis of secreted cystatin F in plasma according to the AD stage from mild (n = 15) to moderate (n = 15) to severe dementia (n = 15). E, F Correlations of the cystatin F level with the Aβ40 and Aβ42 levels in the plasma of patients with AD by Pearson correlation coefficient analysis. G-K Correlations of cystatin F levels with MMSE, MoCA, RAVLT-I, RAVLT-D and CDR scores by Pearson correlation coefficient analysis. The data are presented as the means ± SD and were analysed using Student’s t test and one-way ANOVA. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001