Grases F, Garcia-Gonzalez R, Genestar C, Torres J J, March J G
Department of Chemistry, University of Balearic Islands, Palma de Mallorca, Spain.
Clin Chim Acta. 1998 Jan 30;269(2):147-57. doi: 10.1016/s0009-8981(97)00198-8.
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.
在雄性大鼠中研究了维生素A缺乏对尿石症的影响。与对照组相比，缺乏维生素A的饮食导致受试大鼠尿液成分发生重要变化。主要影响之一是接受缺乏维生素A饮食的大鼠尿中糖胺聚糖和锌的浓度降低。在治疗组和对照组之间还发现血浆维生素E以及维生素E/维生素A的比例存在显著差异，但总体而言，维生素A没有重要差异。然而，两组之间维生素A的肾脏含量存在显著差异。另一方面，与对照组相比，用缺乏维生素A的饮食处理的大鼠覆盖乳头的立方上皮病变严重。还研究了尿石症患者的血浆维生素A和E水平，并与对照组进行了比较。血浆维生素A水平未观察到显著差异；然而，明显观察到维生素E以及维生素E/维生素A的比例显著增加。这些结果可能与结石形成者肾脏中可能存在的维生素A缺乏有关，这是导致尿石形成的多种因素之一。此外，结石形成者中通常存在的重要尿结晶抑制剂如焦磷酸盐和植酸盐的缺乏，也可能与肾脏中维生素A水平低有关，而维生素A水平低会阻止此类抑制剂的酶促降解。
