title: Age-related changes of vitamin A status.
abstract: Ageing is an independent risk factor for the development of cardiovascular disease. The ageing process is known to be associated with increased oxidative stress and an increased risk for cardiovascular and other diseases, such as cancer. To delay this process, therapeutic strategies involving the use of naturally occurring antioxidants, such as vitamin A, have gained considerable interest. Therefore, we wanted to investigate in a model of mammalian ageing whether changes in tissue and plasma levels of vitamin A occur with increasing age. This would constitute a prime rationale for its dietary supplementation. Experiments were performed in three different age groups (4-6 months old, 19 months old, 32-35 months old) of F1 (F344 x BN) healthy male rats that were fed a normal diet without any additional supplementation. Vitamin A and carotenoids in plasma and major organs were measured by reverse-phase high-performance liquid chromatography. In 3-year-old rats, vitamin A levels were found to be decreased in plasma (P < 0.0001) as compared with young and middle-aged animals. However, they were markedly increased in the main storage organ (ie, the liver) (P < 0.01-0.0001), and also in the aortic vessel wall. They were undetectable in the heart, irrespective of age. Increased tissue levels of vitamin A, especially in the vasculature, may be part of an age-associated self-regulatory process of adaptation, possibly as a counter-regulation against oxidative tissue damage. Based upon the assumption that in elderly humans, as in our animal model, a similar demand-regulated mechanism may work independently of additional dietary vitamin A supplementation, one may question the strategy of large clinical interventional trials using vitamin A or its derivatives beyond normal dietary intake.
authors.affiliation: Division of Cardiology, Cardiovascular Centre, University Hospital Zurich, Switzerland.
authors.forename: Bernd
authors.initials: B
authors.lastname: van der Loo
authors.forename: Ralf
authors.initials: R
authors.lastname: Labugger
authors.forename: Claude P
authors.initials: CP
authors.lastname: Aebischer
authors.forename: Markus
authors.initials: M
authors.lastname: Bachschmid
authors.forename: Volker
authors.initials: V
authors.lastname: Spitzer
authors.forename: Juliane
authors.initials: J
authors.lastname: Kilo
authors.forename: Lukas
authors.initials: L
authors.lastname: Altwegg
authors.forename: Volker
authors.initials: V
authors.lastname: Ullrich
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Lüscher
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D002318:Cardiovascular Diseases / Q000209:etiology; D002851:Chromatography, High Pressure Liquid; D008099:Liver / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism; D051381:Rats; D014018:Tissue Distribution; D014801:Vitamin A / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D014801:Vitamin A