PLATELET MAO-B ACTIVITY AND VITAMIN-B12 IN OLD-AGE DEMENTIAS

Platelet MAO-B activity, serum vitamin B-12 levels, and plasma folate were measured in patients suffering from presenile (AD) and senile (SDAT) dementia of Alzheimer-type, and vascular dementia (VD). MAO-B was higher in the SDAT group than in AD and controls. An inverse relationship between MAO-B activity and vit. B-12 levels was documented in the whole group and in each category studied; furthermore, MAO-B was positively related to age. All the patients were then divided into two groups, according to vit. B-12 levels (Group. I: < 200 pg/mL; Group II: greater-than-or-equal-to 200 pg/mL); Group I showed a significantly higher MAO-B activity with respect to Group II. The results indicate the existence of a negative association between platelet MAO-B activity and serum levels of vitamin B-12 and confirm the existence of biological differences between presenile and senile dementia of Alzheimer type.