Immunolocalization of duodenal cytochrome B: a relationship with circulating markers of iron status
Immunolocalization of duodenal cytochrome B: a relationship with circulating markers of iron status
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DOI：
10.1111/j.1365-2362.2006.01732.x
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发表时间：
2006-12-01
影响因子：
5.5
通讯作者：
Powell, J. J.
中科院分区：
文献类型：
--
作者：
Li, A. C. Y.;Warley, A.;Powell, J. J.
背景刷状缘铁还原酶（Dcytb）在十二指肠上皮细胞刷状缘表达，对膳食铁的吸收至关重要。在严重缺铁性贫血中Dcytb表达增加，但在更典型的轻度缺铁性贫血中的情况尚不清楚。本研究探讨了正常铁状态和轻度铁缺乏患者中Dcytb的表达及其与肠上皮细胞铁状态的关系。材料与方法32例常规上消化道内镜检查患者的十二指肠活检标本和血液标本。二十三个标本（6铁缺乏和17铁充满）进行处理的光学显微镜（LM）和免疫组化与抗体对Dcytb和重/轻链铁蛋白亚基。剩下的9个活组织检查（3个缺铁和6个充满铁）进行了电子显微镜（EM）。结果LM过程显示Dcytb在肠上皮细胞刷状缘上的免疫标记强度与血清铁饱和度呈强负相关（P < 0.001），但该抗原与血红蛋白（P = 0.08）或血清铁蛋白浓度（P = 0.4）仅呈弱负相关。电镜证实抗Dcytb抗体优先标记微绒毛而非肠上皮细胞胞浆（P = 0.001），而抗铁蛋白抗体优先标记胞浆（P < 0.02）。结论轻度缺铁时肠上皮细胞刷状缘Dcytb表达增加，可能与血清铁饱和度有关。与肠细胞铁蛋白表达缺乏相关性值得进一步研究，直接测量细胞内铁。
Background The brush border ferric reductase (Dcytb) is critical for the absorption of dietary iron and appears to be expressed on the duodenal enterocyte brush border. The Dcytb expression is increased in severe iron-deficient anaemia, but the situation in a more typical mild iron deficiency is unclear. This study investigated Dcytb expression in patients with normal iron status or mild iron deficiency and its relationships with enterocyte iron status.Materials and methods Duodenal biopsy specimens and blood samples were obtained from 32 patients undergoing routine upper gastrointestinal endoscopy. Twenty-three specimens (six iron-deficient and 17 iron-replete) were processed for light-microscopy (LM) and for immunohistochemistry with antibodies against Dcytb and heavy/light chain ferritin subunits. The nine remaining biopsies (three iron-deficient and six iron-replete) were processed for electron microscopy (EM). Immunolocalization of Dcytb and intracellular ferritin was performed with appropriate primary antibodies followed by 10-nm gold conjugate labels.Results The LM process showed a strong negative correlation between immunolabelling intensity of Dcytb on the enterocyte brush border and serum iron saturation (P < 0.001), but only a weak negative correlation between this antigen and haemoglobin (P = 0.08) or serum ferritin concentrations (P = 0.4). EM confirmed anti-Dcytb preferential labelling of microvilli rather than enterocyte cytoplasm (P = 0.001), but preferential antiferritin labelling of cytoplasm (P < 0.02). There was no correlation with enterocyte cytoplasmic ferritin labelling (i.e. enterocyte iron status and Dcytb expression).Conclusion Enterocyte Dcytb brush border expression is increased even in mild iron deficiency and may be related to serum iron saturation. The lack of correlation with enterocyte ferritin expression deserves further study with direct measurement of intracellular iron.