Gavrilov V, Yermiahu T, Gorodischer R
Pediatric Pharmacology Laboratory, Soroka Medical Center and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Kidney Int. 2006 Jan;69(1):173-7. doi: 10.1038/sj.ki.5000024.
Renal dysfunction is a common and serious complication in multiple myeloma (MM) patients. Renal proximal tubule injury is characteristic in MM, and may result in disturbed renal handling of various vitamins. The abnormal excretion of vitamins in urine may result in their low serum levels. The goal of this study was to investigate the urinary excretion of retinol in MM and its relationship with serum retinol concentration. For this purpose, 24 MM patients and 10 healthy individuals were studied. Serum and urinary retinol and retinol-binding protein (RBP) were measured by the high-performance liquid chromatography method and enzyme-linked immunosorbent assay, respectively. The study showed that 58% of MM patients excreted retinol in urine, while only 29% had elevated serum creatinine (P<0.05). There was a strong and highly significant correlation between urinary retinol and RBP (r=0.973, P<0.006). Patients with normal and mildly elevated serum creatinine who excreted retinol in urine had a marked decrease in serum retinol (P<0.007). On the other hand, serum retinol was not decreased in patients with moderate or severe renal failure, despite its urinary loss. Our data indicate that (i) urinary retinol is a more frequent marker of renal dysfunction than elevated serum creatinine in MM patients, (ii) serum retinol is decreased in MM with normal or mildly elevated serum creatinine, but not in patients with moderate/severe renal failure, and (iii) urinary retinol may serve as a diagnostic marker of renal proximal tubule dysfunction in MM patients.
肾功能不全是多发性骨髓瘤（MM）患者常见且严重的并发症。肾近端小管损伤是MM的特征性表现，可能导致肾脏对各种维生素的处理紊乱。维生素经尿液异常排泄可能导致其血清水平降低。本研究的目的是调查MM患者尿液中视黄醇的排泄情况及其与血清视黄醇浓度的关系。为此，对24例MM患者和10名健康个体进行了研究。血清和尿液中的视黄醇及视黄醇结合蛋白（RBP）分别采用高效液相色谱法和酶联免疫吸附测定法进行检测。研究表明，58%的MM患者尿液中排泄视黄醇，而仅有29%的患者血清肌酐升高（P<0.05）。尿液视黄醇与RBP之间存在强且高度显著的相关性（r=0.973，P<0.006）。尿液中排泄视黄醇的血清肌酐正常和轻度升高的患者血清视黄醇显著降低（P<0.007）。另一方面，尽管存在尿液丢失，但中度或重度肾衰竭患者的血清视黄醇并未降低。我们的数据表明：（i）在MM患者中，尿液视黄醇是比血清肌酐升高更常见的肾功能不全标志物；（ii）血清肌酐正常或轻度升高的MM患者血清视黄醇降低，但中度/重度肾衰竭患者并非如此；（iii）尿液视黄醇可作为MM患者肾近端小管功能障碍的诊断标志物。
