Kancha R K, Anasuya A
Department of Biophysics, National Institute of Nutrition, Hyderabad, India.
Biochem Med Metab Biol. 1992 Feb;47(1):1-9. doi: 10.1016/0885-4505(92)90002-g.
Studies in experimental animals showed that vitamin A deficiency enhanced the severity of urinary calculi disease. In India, children with low socioeconomic status are the major victims of bladder stone disease, and vitamin A deficiency is also more prevalent among these children. However, no systematic study is available to correlate the vitamin A-deficient status of children with their predisposition to urinary calculi disease. Vitamin A-deficient and normal boys were the subjects of this study. Twenty-four-hour samples of urine were collected from all the children at the beginning of the study and after normalizing the vitamin A status of the deficient children. Important risk factors were estimated in urine. Plasma vitamin A levels were also measured in these children. Among the deficient group, only children with plasma vitamin A levels of 15 micrograms and lower exhibited calcium oxalate crystalluria. Most importantly, abnormal crystalluria was observed in all children whose plasma vitamin A levels were 13 micrograms/dl or less. Compared to normal children the urine of vitamin A-deficient children showed the following changes: (a) reduced concentration of crystal growth inhibitors, namely citrate and glycosaminoglycans; (b) a decline in inhibitory activity toward calcium oxalate crystal growth; and (c) enhanced excretion of high risk factors, namely calcium and oxalate. Correction of vitamin A status normalized the above abnormal properties of urine. The results of this study strongly support the hypothesis that the vitamin A-deficient state is one of the factors that can enhance the risk of urolithiasis in susceptible populations.
对实验动物的研究表明，维生素A缺乏会加重尿路结石疾病的严重程度。在印度，社会经济地位低下的儿童是膀胱结石疾病的主要受害者，并且维生素A缺乏在这些儿童中也更为普遍。然而，尚无系统研究将儿童维生素A缺乏状态与其尿路结石疾病易感性相关联。本研究以维生素A缺乏和正常的男孩为对象。在研究开始时以及使缺乏维生素A的儿童的维生素A状态正常化之后，收集了所有儿童24小时的尿液样本。对尿液中的重要危险因素进行了评估。还测量了这些儿童的血浆维生素A水平。在缺乏维生素A的组中，只有血浆维生素A水平为15微克及以下的儿童出现草酸钙结晶尿。最重要的是，在所有血浆维生素A水平为13微克/分升或更低的儿童中均观察到异常结晶尿。与正常儿童相比，维生素A缺乏儿童的尿液呈现出以下变化：（a）晶体生长抑制剂（即柠檬酸盐和糖胺聚糖）的浓度降低；（b）对草酸钙晶体生长的抑制活性下降；（c）高风险因素（即钙和草酸盐）的排泄增加。维生素A状态的纠正使尿液的上述异常特性恢复正常。本研究结果有力地支持了以下假设：维生素A缺乏状态是可增加易感人群尿路结石风险的因素之一。
