title: Vitamin A and urolithiasis.
abstract: The effects of vitamin A deficiency on urolithiasis were investigated in male rats. A vitamin A-deficient diet caused important changes in the composition of the urine of the treated rats when compared with controls. One of the main effects was a decrease in the concentration of urinary glycosaminoglycans and zinc in the rats receiving the vitamin A-deficient diet. Significant differences were also found in plasma vitamin E and in the relation of vit E/vit A between treated and control groups but, in general, with no important differences in vitamin A. Nevertheless, significant differences in kidney content of vitamin A were observed between both groups. On the other hand, lesions of the cuboidal epithelium that covers the papillae in rats treated with the vitamin A-deficient diet were severe when compared with controls. The vitamin A and E plasma levels in urolithiasic humans were also investigated and compared with those found in a control group. No significant differences were observed in plasma vitamin A levels; nevertheless a significant increase in vitamin E and in the vit E/vit A ratio was clearly observed. These results could be related to a possible deficit of vitamin A in kidneys of stone formers, this being one of the diverse factors that can contribute to urolith development. Moreover, the deficit of important urinary crystallization inhibitors normally found in stone-formers, such as pyrophosphate and phytate, can also be related to the presence of low levels of renal vitamin A which prevents the enzymatic degradation of such inhibitors.
authors.affiliation: Department of Chemistry, University of Balearic Islands, Palma de Mallorca, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Grases
authors.forename: R
authors.initials: R
authors.lastname: Garcia-Gonzalez
authors.forename: C
authors.initials: C
authors.lastname: Genestar
authors.forename: J J
authors.initials: JJ
authors.lastname: Torres
authors.forename: J G
authors.initials: JG
authors.lastname: March
mesh_terms: D000818:Animals; D006801:Humans; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014545:Urinary Calculi / Q000209:etiology*; D014801:Vitamin A / Q000097:blood; D014802:Vitamin A Deficiency / Q000150:complications*; D014810:Vitamin E / Q000097:blood
chemical_list: D014801:Vitamin A; D014810:Vitamin E