title: Analogues, ageing and aberrant assimilation of vitamin B12 in Alzheimer's disease.
abstract: Vitamin B12 assimilation might be disrupted in patients with Alzheimer's disease. We therefore measured B12 carrier protein saturation and inactive B12 'analogues' in patients compared with healthy elderly individuals in a prospective case-controlled survey. Twenty-three patients, aged 60 or over, with features compatible with DSM-IV criteria for primary degenerative dementia of the Alzheimer type were recruited together with 18 cognitively intact age-matched control subjects. Total vitamin B12 (active corrinoids), holo- and apo-haptocorrin and transcobalamin were measured in serum. B12 analogues (inactive corrinoids) were estimated from the difference between R-binder-determined corrinoids and an intrinsic factor based B12 assay. Alzheimer patients had significantly lower active corrinoid than control subjects and the analogue/corrinoid ratio was significantly higher in the Alzheimer group. The inter-relationship between age, analogues and transcobalamin polarised patients into two distinct groups. Two disparate mechanisms might exist for the development of cerebral B12 deficiency in Alzheimer's disease, although both imply a disruption of selective B12 assimilation and analogue elimination in such patients.
authors.affiliation: Gardden Road Surgery, Rhosllanerchrugog, Wrexham, North Wales, UK. Andrew@mccaddon.demon.co.uk
authors.forename: A
authors.initials: A
authors.lastname: McCaddon
authors.forename: P
authors.initials: P
authors.lastname: Hudson
authors.forename: L
authors.initials: L
authors.lastname: Abrahamsson
authors.forename: H
authors.initials: H
authors.lastname: Olofsson
authors.forename: B
authors.initials: B
authors.lastname: Regland
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D000544:Alzheimer Disease / Q000097:blood*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000097:blood*
chemical_list: D014805:Vitamin B 12