Serum Homocysteine, Dehydroepiandrosterone Sulphate and Lipoprotein (a) in Alzheimer's Disease and Vascular Dementia

Alzheimer's disease (AD) and vascular dementia (VAD) are the major forms of dementia affecting elderly people, in which the levels of many metabolites are altered in cerebrospinal fluid (CSF) and serum. These metabolites could be risk factors or potential biomarkers, but the significance of some of these are not clearly understood in the context of the disease pathogenesis. In the present study serum levels of homocysteine, dehydroepiandrosterone sulphate (DHEA-S) and lipoprotein (a) or Lp(a) have been measured by ELISA using commercial kits in AD (n = 40), VAD (n = 40) and age matched control subjects (n = 40). The data are compared by ANOVA and post-hoc analysis. The serum homocysteine is markedly elevated compared to control both in AD and VAD subjects, but to a significantly higher extent in the latter. Lp(a) is increased in the serum of VAD subjects only compared to control. Likewise, serum DHEA-S level is lowered in AD but not in VAD compared to control. The analysis of the present data and those published by others suggest that alterations in homocysteine and Lp(a) in serum are indicators of vascular pathology in AD or VAD, while the lowering of serum DHEA-S is a consequence of AD pathology.