Higaki S, Akazawa A, Nakamura H, Yanai H, Yoshida T, Okita K
First Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan.
J Gastroenterol Hepatol. 1999 Jul;14(7):709-14. doi: 10.1046/j.1440-1746.1999.01938.x.
The metaplastic polyp of the colon is a non-neoplastic lesion that is generally identified as white, flat and having a smooth surface. In general, this polyp is small, is less than 5 mm in diameter but is occasionally larger than 5 mm in diameter, and forms a swelling. The aims of the present study were to clarify the factors that determine the morphology of protruding metaplastic polyps. More specifically, we investigated whether the metaplastic polyp forms as a result of an abnormality in cell proliferation or inflammation of the region.
We examined 15 endoscopically resected metaplastic polyps of the colon having a longitudinal diameter of more than 5 mm. To study aspects of cell proliferation, we used proliferating-cell nuclear antigen (PCNA) staining. For examination of histological changes caused by inflammation, we used alpha-smooth muscle actin (alphaSMA) staining, in which myofibroblasts are specifically stained.
Metaplastic polyps showed significantly higher expression of PCNA, not only in the deep layer, but also in the intermediate and superficial layers, compared with the normal mucosa of the colon. In the protruding metaplastic polyps, anti-alphaSMA staining revealed bundle-like myofibroblasts in the interstitium.
The factors responsible for the formation of non-neoplastic metaplastic polyps larger than 5 mm with a protruding morphology are: an increased number of epithelial cells due to the movement of these cells toward the ductal epithelium in the proliferating zone; and expansion of interstitial tissues due to infiltration of myofibroblasts and other inflammatory cells in response to inflammation.
结肠化生息肉是一种非肿瘤性病变，通常表现为白色、扁平且表面光滑。一般来说，这种息肉较小，直径小于5mm，但偶尔直径会大于5mm并形成隆起。本研究的目的是阐明决定突出型化生息肉形态的因素。更具体地说，我们调查了化生息肉是否是由于细胞增殖异常或该区域的炎症所致。
我们检查了15例经内镜切除的纵向直径大于5mm的结肠化生息肉。为了研究细胞增殖方面，我们使用增殖细胞核抗原（PCNA）染色。为了检查由炎症引起的组织学变化，我们使用α-平滑肌肌动蛋白（αSMA）染色，其中肌成纤维细胞会被特异性染色。
与结肠正常黏膜相比，化生息肉不仅在深层，而且在中层和表层均显示出PCNA表达显著更高。在突出型化生息肉中，抗αSMA染色显示间质中有束状肌成纤维细胞。
导致形态突出的、直径大于5mm的非肿瘤性化生息肉形成的因素为：增殖区的上皮细胞向导管上皮移动导致上皮细胞数量增加；以及肌成纤维细胞和其他炎症细胞因炎症浸润而导致间质组织扩张。
