TRPC6 mRNA levels in peripheral leucocytes of patients with Alzheimer's disease and mild cognitive impairment: A case-control study.

BACKGROUND: Transient receptor potential canonical (TRPC) 6 inhibits Aβ in Alzheimer's disease (AD) mouse brain and improves the behavioral performance.

AIMS: To evaluate the association of TRPC6 expression in peripheral leucocytes from AD and mild cognitive impairment (MCI) patients and to explore its potential value in early diagnosis of AD.

METHODS: TRPC6 mRNA levels in peripheral leucocytes were detected by quantitative real-time PCR. The Spearman correlation test was used to ascertain the associations between TRPC6 and the scores of MMSE, ADL, CSDD, CDR. The Receiver Operating Characteristic (ROC) curve was drawn to evaluate the diagnostic potential of TRPC6 for AD and MCI.

RESULTS: There were 108 CE, 136 MCI, 164 Con and 60 PD in the study. The expression of TRPC6 mRNA level in peripheral leucocytes was significantly lower: 1) in patients with AD and MCI compared to Con; 2) in AD compared to MCI; 3) in hospitalized AD compared to AD from communities. There was a significantly positive correlation between TRPC6 mRNA and MMSE score (p = .001, R = 0.327). Significantly inverse correlations were found between TRPC6 and CDR score (p < 0.001, R = -0.303) as well as between TRPC6 and ADL score (p = .001, R = -0.342) for all AD. The area under curve of ROC was 0.881 for the classification of AD, and 0.706 for the classification of MCI, respectively.

CONCLUSION: TRPC6 expression is inversely correlated with cognitive performance of AD. TRPC6 in peripheral leucocytes may be a potential biomarker for the diagnosis of AD.