Histopathological study of Barrett's adenocarcinoma using analyses of mitochondrial DNA mutations

为阐明Barrett‘s食道(BE)进展为食管腺癌(EAC)的组织起源，我们检测了不同病变(BE、EAC、鳞状上皮异型增生和鳞癌)的线粒体DNA突变和细胞色素C氧化酶的免疫组织化学染色。这些损伤是在大鼠十二指肠内容物反流模型上诱导的，这是以前报道的没有胃切除的食道空肠吻合术的模型。在此之前，我们曾报道过高饮食动物脂肪通过增加胆汁中牛磺酸结合物的浓度来改变胆汁酸的组成。这些增加的胆汁酸促进了BE和Barrett异型增生的发展，进展为EAC。在本研究中，反流动物模型根据饮食的不同分为两组。标准日粮组饲喂低豆油日粮(CE-2)，高脂组饲喂高牛脂日粮(Quick Fat)。术后10周、20周和30周处死存活的动物。采用免疫组织化学和酶组织化学方法对切除的食道组织中细胞色素c氧化酶进行分析。在显示线粒体突变的病例中，检测到细胞色素c氧化酶阴性的病灶，这些病灶以时间依赖的方式增加。与标准饮食组相比，高脂组的病灶数量明显增加。我们观察到，细胞色素c氧化酶阴性灶首先出现在BE的增殖区和杯状细胞，然后以类似于肠隐窝分裂的方式增殖。在正常的再生鳞状上皮中也可检测到这些病灶。然而，我们不能证明BE的发生与线粒体突变之间的关系。

To elucidate the histogenesis of Barrett's esophagus (BE) progressing to esophageal adenocarcinoma (EAC), we examined mitochondrial DNA mutations and performed immunohistochemical staining and enzyme histochemistry of cytochrome c oxidase in various lesions (BE, EAC, squamous dysplasia, and squamous cell carcinoma). These lesions were induced in rat duodenal contents reflux models, which were previously reported models that had undergone esophagojejunostomy without gastrectomy. Previously, we reported that high dietary animal fat alters bile acid composition by increasing the concentration of taurine conjugates in bile. These increased bile acids promote the development of BE and Barrett's dysplasia progressing to EAC. In the present study, the reflux animal models were divided into two groups on the basis of their diet. The standard diet group was fed with a low soybean oil diet (CE-2) and the high-fat group was fed with a high cow fat diet (Quick Fat). The animals that survived the operation were sacrificed at postoperative weeks 10, 20, and 30. Cytochrome c oxidase was analyzed in the resected esophagi by both immunohistochemical staining and enzyme histochemistry. Cytochrome c oxidase-negative foci were detected in cases that demonstrated mitochondrial mutations, and these foci increased in a time-dependent manner. A significantly higher number of foci were observed in the high-fat group compared with the standard diet group. We observed that cytochrome c oxidase-negative foci first appeared in the proliferative zone of BE with goblet cells, and then proliferated in a manner similar to crypt fission of intestine. These foci were also detected in the normal regenerative squamous epithelium. However, we could not demonstrate the relationship between BE carcinogenesis and mitochondrial mutations.