Pazianas M, Zaidi M, Subhani J M, Finch P J, Ang L, Maxwell J D
Ralston Penn Center Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
Calcif Tissue Int. 2003 Apr;72(4):485-90. doi: 10.1007/s00223-001-2135-2. Epub 2003 Feb 10.
Animal studies have demonstrated that the highest concentration of vitamin D receptors (and greatest capacity for active calcium absorption) occurs in the proximal duodenum. By passing the duodenum following Polya/Billroth II gastrectomy could result in the development of a metabolic bone disease and low bone mineral density (BMD). We thus compared the vitamin D receptor (VDR) concentration in mucosal biopsies taken at endoscopy from two functionally corresponding areas of the small intestine: the jejunum (or efferent loop) in 21 patients with a history of Polya/Billroth II gastrectomy and the second part of the duodenum in age/sex-matched control subjects. We also measured the BMD by dual energy X-ray absorptiometry. The mean VDR concentration was not significantly different between the two groups (patients vs controls, fmol/mg protein, mean +/- SE: 34.99 +/- 2.57 vs 34.67 +/- 3.71; P = 0.22), even when subgrouped as males (36.22 +/- 3.16 vs 31.2 +/- 4.24; P = 0.351) or females (31.93 +/- 4.7 vs 43 +/- 6.76; P = 0.193). In Polya/Billroth II gastrectomy patients, the VDR concentration in the efferent loop declined with age (r = -0.78, P = 0.02). In the same group, BMD, as compared with matched controls, was significantly reduced at the lumbar spine (Z-score: patients vs controls: -1.138 vs 0.099, P = 0.01), but not at the femoral neck (Z-score: -0.69 vs 0.7, P = 0.084). There was no correlation between VDR and time since operation or BMD. These results suggest that following Polya/Billroth II gastrectomy, the functional capacity of the jejunal efferent loop in reference to VDR concentration is similar to that of the second part of the duodenum in normal subjects. Therefore, the reduced BMD in our patients, also a common finding in other studies, may not be secondary to the reduced capacity of the VDR system that facilitates the active calcium transport pathway in the proximal small intestine.
动物研究表明，维生素D受体浓度最高（以及活性钙吸收能力最强）的部位是十二指肠近端。波利亚/毕罗Ⅱ式胃切除术后绕过十二指肠可能会导致代谢性骨病和低骨矿物质密度（BMD）的发生。因此，我们比较了通过内镜检查从两个功能相对应的小肠区域获取的黏膜活检组织中的维生素D受体（VDR）浓度：21例有波利亚/毕罗Ⅱ式胃切除术病史患者的空肠（或输出袢），以及年龄/性别匹配的对照受试者的十二指肠第二部。我们还通过双能X线吸收法测量了骨矿物质密度。两组之间的平均VDR浓度无显著差异（患者组与对照组，fmol/mg蛋白，均值±标准误：34.99±2.57 vs 34.67±3.71；P = 0.22），即使分为男性亚组（36.22±3.16 vs 31.2±4.24；P = 0.351）或女性亚组（31.93±4.7 vs 43±6.76；P = 0.193）也是如此。在波利亚/毕罗Ⅱ式胃切除术患者中，输出袢中的VDR浓度随年龄下降（r = -0.78，P = 0.02）。在同一组中，与匹配的对照组相比，腰椎的骨矿物质密度显著降低（Z值：患者组与对照组：-1.138 vs 0.099，P = 0.01），但股骨颈处未降低（Z值：-0.69 vs 0.7，P = 0.084）。VDR与术后时间或骨矿物质密度之间无相关性。这些结果表明，波利亚/毕罗Ⅱ式胃切除术后，空肠输出袢在VDR浓度方面的功能能力与正常受试者十二指肠第二部相似。因此，我们患者中骨矿物质密度降低的情况，其他研究中也常见，可能并非继发于促进近端小肠中活性钙转运途径的VDR系统功能降低。
