Objective To investigate changes in serum brain-derived neurotrophic factor (BDNF)levels in patients with Alzheimer's disease(AD).Methods Venous blood samples were collected from 40 AD patients,40 amnestic mild cognitive impairment(aMCI)patients and 40 normal controls.Serum BDNF levels were analyzed by enzyme-linked immunosorbent assay (ELISA).The relationships of serum BDNF levels with age,gender,educational level,mini-mental state examination (MMSE) score and Beck depression scale-Ⅱ (BD Ⅰ-Ⅱ)score in AD patients were analyzed.Results Serum BDNF levels were lower in AD patients than in patients with aMCI and normal controls(4.6± 1.9 μg/L vs.9.3 ± 4.7 μg/L,10.2 ± 1.8 μg/L,F =71.083,P ＜0.05).There were 12 mild AD patients,18 moderate AD patients and 10 severe AD patients,and serum BDNF levels decreased with increased disease severity(5.5±5.4 μg/L,4.9±4.2 μg/L vs.3.8±3.0 μg/L,F=78.214,P＜0.05).Serum BDNF levels decreased in 29 AD patients aged over 65 years compared with 11 AD patients aged 65 years and younger(3.6±2.2 μg/L vs.4.64±1.06 μg/L,P＜0.05).Serum BDNF levels had no correlation with gender,educational level or BD Ⅰ-Ⅱ score(P＞0.05).Pearson correlation analysis showed that serum BDNF levels had a positive correlation with MMSE score(r =0.428,P＜0.05).Conclusions Advanced age is associated with decreased serum levels of BDNF in AD patients.Decreased serum levels of BDNF in AD patients are related to the severity of cognitive impairment.There is no correlation between serum BDNF levels and depressive symptoms in AD patients.

Sodium prasterone sulfate (DHEAS) and dehydroepiandrosterone (DHEA) are endogenous steroid compounds, which are synthesized and secreted by adrenal gland.They are the precursors of steroid hormones,including sex hormone.Based on intracrine theory,the majority of postmenopausal women will have vaginal atrophy,which is caused by the absence of endogenous hormones,DHEAS or DHEA.Moderate supplementation of DHEAS can relieve the associated symptoms of vaginal atrophy.Many clinical researches have demonstrated that DHEAS can efficiently alleviate the related symptoms of vaginal atrophy.The concentration of androgen and estrogen in patients with long term use of DHEAS are still in the normal intracrine physiological range.Therefore,DHEAS may become the first drug for the treatment of vaginal atrophy in the future.