title: The age-related decline in intestinal lipid uptake is associated with a reduced abundance of fatty acid-binding protein.
abstract: Aging is associated with changes in the absorptive capacity of the small intestine. We tested the hypotheses that (i) aging is associated with a decline in lipid absorption, and that (ii) this decreased lipid absorption is due to a decline in the abundance of mRNA and/or the enterocyte cytosolic intestinal FA-binding protein (I-FABP), the liver FA-binding protein (L-FABP), and the ileal lipid-binding protein (ILBP). In vitro uptake studies were performed on Fischer 344 rats at ages 1, 9, and 24 mon. Northern blotting (L-FABP, ILBP) and immunohistochemistry (I-FABP, ILBP) were performed. Aging was associated with decreased animal weights, but the surface area of the intestine was not significantly altered with age. The rates of ileal uptake of 16:0, 18:0, 18:1, and 18:2 were reduced by greater than 50% with aging when expressed on the basis of mucosal weight. This decline was not associated with reduced expression of mRNA for L-FABP or ILBP but was associated with a 50% decrease in the abundance of I-FABP and a 40% decrease in the abundance of ILBP. Thus, the decrease with aging in the ileal uptake of some FA when rates were expressed on the basis of mucosal weight was associated with a reduced abundance of I-FABP and ILBP.
authors.affiliation: Nutrition and Metabolism Group, Division of Gastroenterology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Trudy D
authors.initials: TD
authors.lastname: Woudstra
authors.forename: Laurie A
authors.initials: LA
authors.lastname: Drozdowski
authors.forename: Gary E
authors.initials: GE
authors.lastname: Wild
authors.forename: M T
authors.initials: MT
authors.lastname: Clandinin
authors.forename: Luis B
authors.initials: LB
authors.lastname: Agellon
authors.forename: Alan B R
authors.initials: AB
authors.lastname: Thomson
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001835:Body Weight; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D050556:Fatty Acid-Binding Proteins; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology*; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism; D007421:Intestine, Small / Q000033:anatomy & histology / Q000378:metabolism; D050356:Lipid Metabolism; D009929:Organ Size; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D002352:Carrier Proteins; C493319:FABP1 protein, human; C493321:Fabp1 protein, rat; D050556:Fatty Acid-Binding Proteins; D020033:Protein Isoforms