Decreased serum levels of the angiogenic factors VEGF and TGF-β1 in Alzheimer's disease and amnestic mild cognitive impairment

Growing evidence suggests that angiogenesis might represent a new pathogenic mechanism involved in the progression of Alzheimer's disease (AD). Vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGF-β1) are two cytokines having a pivotal role in angiogenesis. In the present study, serum VEGF and TGF-β1 levels were measured with ELISA in 31 AD patients, 28 amnestic mild cognitive impairment (aMCI) patients and 29 controls. VEGF concentration in serum of AD patients was significantly lower than that in aMCI patients and controls (p < 0.05). Serum VEGF levels in aMCI patients were also significantly decreased compared to controls (p < 0.05). Serum TGF-β1 levels in AD patients were significantly lower than those in controls (p < 0.05). There was a negative correlation between serum VEGF/TGF-β1 levels and the Clinical Dementia Rating (CDR) scores (p < 0.05) and a positive correlation between serum VEGF levels and TGF-β1 levels (p < 0.05). These observations suggest that angiogenesis might be involved in the onset process of AD and the decrease of angiogenic factors might be related to the severity of cognitive impairment.