Early Diagnosis Value Of Serum β Amyloid Protein And Tau Protein In Patients With Subcortical Ischemic Vascular Dementia

Objective We respectively detected the serum levels of Aβ_38, Aβ₄₀, Aβ₄₂, tau protein and excessive phosphorylated tau protein (p-tau) in SIVD(subcortical ischemic vascular disease), vascular mild cognitive impairment (MCI-V) and controls in order to explore the value of early diagnosis on patients with SIVD.Methods We chose 38 cases of patients with SIVD (SIVD group), 42 cases of patients with MCI-V (MCI-V group), and 36 normal elderly as control group. SIVD was defined based on the diagnostic criteria for SIVD by Erkinjuntti and colleagues. MCI-V was defined based on the diagnostic criteria for MCI-V by Frisoni and colleagues. We investigated vascular risk factors such as smoking, alcohol consumption, hypertension, diabetes, dyslipidemia and heart disease. Test the blood pressure, electrocardiogram, fasting glucose, triglycerides (TG), serum total cholesterol (TCH), high-density lipoprotein cholesterol (HDL-C) and Aβ38, Aβ40, Aβ42, tau and p-tau protein levels of fasting serum by ELISA. We evaluated cognitive function by Mini-mental state examination (MMSE) and degree of cognitive impairment by Clinical Dementia Rating Scale (CDR). The statistical software package SPSS, version 10.0 was used for computations. Continuous variable was characterized by mean and standard deviation. Significant group differences of count data were evaluated withχ₂ test. Comparisons of three groups measurement data were evaluated by the SNK-q test. Standard test of significance are P <0.05.Results 1. There are not significantly differences in sex, age, educational year, smoking, alcohol consumption, hypertension, diabetes, heart disease and dyslipidemia among three groups. MMSE of SIVD group was significantly lower than the other groups (P<0.01), while MCI-V group was significantly lower than control group (P<0.01). 2. Aβ₄₀ level of SIVD group was significantly higher than the other groups (P<0.01), while this level of MCI-V group was higher than control group (P<0.05). The serum levels of Aβ₃₈ and Aβ₄₂ in MCI-V group were higher than control, Aβ₃₈ and Aβ₄₂ levels tended to decrease with disease progression and cognitive impairment increased, the levels of in SIVD were lower than the other groups; however the levels of Aβ₃₈ and Aβ₄₂ did not differ among three groups (P>0.05). Tau protein level of SIVD group was significantly higher than the other groups (P<0.01), while this level of MCI-V group was higher than control group (P<0.05); p-tau level of SIVD group was higher than the other groups (P<0.05), while there was no difference between MCI-V group and control group(P>0.05).Conclusions 1. Serum Aβ₄₀ and tau protein may be the meaningful biomarker of early diagnosis and severity for SIVD. 2. In early SIVD the serum levels of Aβ₃₈ and Aβ₄₂ were increase. Aβ₃₈ and Aβ₄₂ levels tended to decrease with disease progression and cognitive impairment increased. However, there was no significant difference; the results need to be verified by larger sample studies. 3. Serum p-tau protein may be the meaningful biomarker of severity for SIVD.