Lipoprotein(a) phenotypes in patients with vascular dementia

We tried to examine if there is a particular distribution pattern of lipoprotein(a) [Lp(a)] phenotypes specific for patients with vascular dementia (VD). Fourteen cases of VD (9 males and 5 females), 18 cases of dementia of the Alzheimer type (DAT)(7 males and 11 females), 29 cases of cerebrovascular disease (CVD) in the chronic phase (18 males and 11 females) and 47 healthy individuals as controls (25 males and 22 females) were examined for serum Lp(a). Serum concentrations and phenotypes of Lp(a) were assessed by ELISA and a test kit for the Lp(a) phenotype, respectively. Serum concentrations of Lp(a) were significantly higher in patients with VD (p < 0.05) as well as patients with CVD (p < 0.01) compared with those in healthy individuals. Serum concentrations of Lp(a) did not significantly differ between patients with DAT and healthy individuals. The incidences of Lp(a) phenotypes containing relatively low-molecular-weight apolipoprotein(a) isoforms were significantly higher in patients with CVD in the chronic phase (p < 0.05) or those with VD (p < 0.01) compared with those in healthy individuals. Distribution patterns of Lp(a) phenotypes did not differ between patients with DAT and healthy individuals. Thus, high serum levels of Lp(a) could be considered a clinical hallmark to distinguish VD from DAT. Abnormally high serum levels of Lp(a) in patients with CVD and VD seemed to be due to specific increases in low-molecular-weight apolipoprotein(a) isoforms in Lp(a).