Immunohistochemical identification of Ito cells and their myofibroblastic transformation in adult human liver

To identify Ito cells in normal and pathological adult human livers, immunohistochemical studies were performed by the avidin-biotin-peroxidase complex method using monoclonal antibodies for -smooth muscle actin (ASMA), desmin, and vimentin. Fifty one needle biopsies, 7 surgically resected specimens, and 5 autopsy specimens were studied. In the normal adult liver vascular smooth muscle cells and pericytes, together with perisinusoidal cells with thin cytoplasmic processes were positive for ASMA. These latter cells formed a loose and discontinuous layer along the sinusoidal walls. Immunoelectron microscopy showed that the ASMA-positive perisinusoidal cells were Ito cells containing fat droplets. The other sinusoidal lining cells were negative for ASMA. In chronic liver disease, ASMA-positive Ito cells showed an increase in number, size, and the intensity of immunostaining in areas of piecemeal necrosis), and formed a continuous cellular network. These cells were dendritic in shape with irregularly elongated cytoplasmic processes and contained an increased amount of microfilaments, in association with loss of the characteristic fat droplets. Thus, their ultrastructural features corresponded to those of myofibroblastic cells. Ito cells showed no staining for desmin in both normal and pathological livers. These results indicate that immunohistochemistry using an anti-ASMA antibody is a sensitive and reliable method for the identification of both normal and transformed Ito cells in adult human livers.     

CD34<Superscript>+</Superscript> fibrocytes, α-smooth muscle antigen-positive myofibroblasts,and CD117 expression in the stroma of invasive squamous cell carcinomas of the oral cavity,pharynx, and larynx

We investigated tumor-free mucosa and squamous cell carcinomas of the oral cavity, the pharynx, and larynx with respect to the presence of stromal CD34⁺ fibrocytes and -smooth muscle antigen (SMA)-positive myofibroblasts. Additionally, stromal expression of CD117 was analyzed. A total of 39 squamous cell carcinomas were assessed immunohistochemically. In all cases investigated, CD34⁺ fibrocytes were found in the tumor-free stroma, whereas -SMA-positive myofibroblasts were lacking. Areas of lymphocytic infiltration disclosed a focal reduction of CD34⁺ fibrocytes. CD117 expression was absent from the tumor-free stroma. Of 39 squamous cell carcinomas, 33 were free of stromal CD34⁺ fibrocytes, and, in 31 carcinomas, stromal -SMA-positive myofibroblasts occurred at least focally. CD117-positive stromal spindle cells were found in 25 carcinomas. Compared with tumor-free mucosa, the number of tissue mast cells was significantly increased in carcinomas. We conclude that stromal remodeling induced by invasive carcinomas is characterized by a loss of CD34⁺ fibrocytes and subsequent gain of -SMA-positive myofibroblasts. The diagnostic impact of this finding is, however, limited by the fact that chronic inflammation may also be accompanied by a focal loss of CD34⁺ fibrocytes.     

Cytoskeletal characteristics of myofibroblasts in benign neoplastic and reactive fibroblastic lesions

Summary The characteristics of the cytoskeleton of myofibroblasts were examined immunohistochemically in 10 extra-abdominal desmoid tumours, 3 palmar and 2 plantar fibromatoses and 5 nodular fasciites; in the cultured cells of one desmoid tumour, and also ultrastructurally in 3 desmoid tumours. Polyclonal anti-desmin antibody reacted with the cells in 7 extra-abdominal desmoid tumours, 1 palmar fibromatosis, 1 plantar fibromatosis and 3 nodular fasciites. Monoclonal antidesmin antibody reacted with cells in only 2 desmoid tumours. Desmin-positive spindle cells were scattered throughout these lesions. There were no marked ultrastructural differences between desmin-positive and desmin-negative desmoids. All specimens except one specimen of nodular fasciitis showed immunoreactivity for alpha-smooth muscle actin and vimentin. Muscle actin-positive cells were observed in all specimens. Cultured cells gave positive reactions with polyclonal desmin antibody as well as to vimentin antibodies and two preparations of actin antibodies, whereas the original tumour did not react with desmin antibody. The present studies suggested that the cytoskeleton of some myofibroblasts in both neoplastic and reactive lesions resembles that of smooth muscle cells.     

Myofibroblasts and myoepithelial cells in human breast carcinoma

Summary Ultrastructural studies of 11 human breast carcinomata revealed that most stromal cells could be arranged in a cell spectrum from fibroblasts, with abundant rough endoplasmic reticulum, to myofibroblasts. In 4 out of 11 cases, myoepithelial cells were observed in the parenchyma at the periphery of some carcinomatous duct-like structures or carcinoma cell nests. The distinction between myofibroblasts and myoepithelial cells was usually easy from their respective locations. Their ultrastructural features were summarized as follows. Myofibroblasts: (1) abundance of rough ER and other cytoplasmic organelles; (2) bundles of microfilaments, 50–70 Å in diameter and associated dense bodies. Myoepithelial cells: (1) bundles of microfilaments 50–70 Å in diameter and associated dense bodies (a common feature); (2) dense bundles of tonofilaments, 80–100 Å in diameter; (3) typical desmosomes which connected them with adjacent myoepithelial or carcinoma cells. Myofibroblasts were occasionally located closely contiguous with carcinoma cells, giving an appearance resembling myoepithelial cells. Even in these instances a distinction between myofibroblasts and myoepithelial cells was possible, since myoepithelial cells had dense bundles of tonofilaments and typical desmosomes, which were not observed in myofibroblasts. No cell types intermediate between myofibroblasts and myoepithelial cells were detected. We could not decide whether myoepithelial cells were neoplastic or not despite the facts that they showed obscured polarity and had partially or completely lost their basal lamina. We conclude that fibroblasts, myofibroblasts and probably some, if not all, smooth muscle cells belong to the same cell system. Myofibroblasts in our material are derived from fibroblasts, while myoepithelial cells are epithelial in origin.Supported in part by Public Health Service Contract No. 1CP23213 from National Cancer Institute, U.S.A. and by a Grant-in-Aid for Cancer Research No. 51-7 from the Ministry of Health and Welfare, Japan     

Stromal myofibroblasts in primary invasive and metastatic carcinomas

Summary A series of 23 primary invasive and 7 metastatic carcinomas was examined by light microscopy (LM), transmission electron microscopy (TEM) and immunofluorescence (IF), the latter employing an anti-actin antibody. The results were correlated with macroscopic features such as retraction and consistency. Stromal cells rich in actin, readily identified by IF in firm and retracted carcinomas, were rare or absent in neoplasms lacking these features. TEM established the myofibroblastic nature of these stromal cells. Alternate sections (LM, IF) of each neoplasm demonstrated that myofibroblasts were more numerous in young mesenchymal stroma than in densely sclerotic areas. The connective tissue adjacent to intraductal mammary carcinoma lacked myofibroblasts, suggesting that epithelial stromal invasion is required to evoke a myofibroblastic stromal response. Myofibroblasts which possess synthetic (type III collagen) and contractile properties may well contribute to the firm consistency and retraction which characterize many carcinomas. The induction of myofibroblasts might represent an important host stromal response directed toward containment of invasive and/or metastatic carcinoma. This response may be especially important in neoplasms with weak antigenicity and/or slow doubling times.Presented in part at the XIIIth Congress of the International Academy of Pathology. Paris, September 15–19, 1980     

Collagen secretion granules in reactive stromal myofibroblasts,with preliminary observations on their occurrence in spindle cell tumours

Summary Collagen secretion granules, representing stages in the intracellular packaging, transport and secretion of collagen-fibril precursor, have been studied by transmission electron microscopy in non-neoplastic human myofibroblasts and in neoplastic cells from a preliminary study of tumours exclusively or partly of spindle cell type. Vesicles, newly separated from Golgi saccules and containing finely fibrillar material, were identified as early presecretory granules, the most immature type of granule. Later stages exhibited longitudinally arranged, densely fibrillar bundles. Subsequently, secretory granules developed more homogeneously dense content. Fibril-containing cisternae near the plasma membrane were interpreted as either endocytotic or lysosomal structures, or as participants in the final stages of secretion. The features by which collagen secretion granules can be distinguished from other Golgi products, in particular melanosomes, Weibel-Palade bodies and lysosomes, are pointed out. The significance of these organelles for cell identification and tumour diagnosis is discussed.     

兔唇创口愈合中肌成纤维细胞变化的实验研究

目的在动物模型中观察肌成纤维细胞的形态学变化,探讨肌成纤维细胞在创口愈合和瘢痕形成过程中的作用.方法选用同一子代纯种新西兰白兔40只,采用Millard's唇裂修复术,制造出创伤愈合瘢痕模型,分别在术后7d、21d、30d、60d、90d进行肉眼观察和瘢痕体积测量,切取上唇肉芽和瘢痕组织在光镜和电镜下进行病理观察.结果肉眼观察兔唇创口愈合在不同时期有不同的变化.测量瘢痕体积的变化,在术后30d,瘢痕收缩较为明显,与7d、90d时有显著意义(P<0.01),在不同时段MFB数量在30d时与其他时段比较有显著意义(P<0.01),呈正态分布.光电镜下观察,术后7d未出现肌成纤维细胞,21d可见少量,术后30d表现得十分活跃,60d后又逐渐减少,90d时基本消失.结论瘢痕体积的缩小,与肌成纤维细胞的参与及胶原收缩、溶解有关.肌成纤维细胞是创口愈合和瘢痕形成过程中的一过性细胞,在参与细胞外基质形成和瘢痕收缩起着重要功能作用.     

增生性烧伤瘢痕的超微病理改变

采用电子显微镜对４例正常皮肤，２０例增生性烧伤瘢痕进行透射电镜和扫描电镜下的超微结构观察。结果显示，增生性烧伤瘢痕与正常皮肤在超微结构方面存在显著的不同．增生性烧伤的超微病理变化表现为：瘢痕上皮细胞间水肿；皮肤附件缺如；成纤维细胞及成肌纤维细胞增殖、功能活跃；胶原纤维排列紊乱，致密分布，其胶原纤维表面有粘多糖沉积，毛细血管管腔闭塞或半闭塞。研究增生性烧伤的超微结构对于阐明其瘢痕增生的机理及探索其防治方法均有重要意义。     

Desmoplasia in Different Degrees of Invasion of Carcinoma Ex-Pleomorphic Adenoma

Stroma desmoplasia was studied by immunohistochemistry for α-smooth muscle actin (α-SMA) in 17 instances of carcinoma ex-pleomorphic adenoma (CXPA) classified according to the presence of epithelial and myoepithelial cells and the degree of invasion: intracapsular, minimally and frankly invasive carcinoma. In “resident” pleomorphic adenoma, no desmoplasia was detected. In invasive areas of the intracapsular type of CXPA with only an epithelial component, desmoplasia started to be revealed by the presence of myofibroblasts close to the capsule. In the minimally invasive type, myofibroblasts were seen in the septum between islands of malignant cells and in focal peripheral areas of the tumor interpreted as the actual front of invasion. In the frankly invasive type of CXPA showing large blocks of cells, intense desmoplasia was seen, also separating the tumor cells from the neighboring normal tissue. In tumors with cords and/or small nests of cells, desmoplasia was very slight. In the invasive type of CXPA with a myoepithelial component, α-SMA expression was seen in the septum between the islands of cells. The expression was less intense and not present in all areas of the stroma. In CXPA with epithelial and myoepithelial cells, myofibroblasts were rarely seen in the septum separating sheets of cells. Thus, we may deduce that the presence of desmoplasia parallels the capacity of invasion of CXPA by epithelial cells, being minimum in the intracapsular and minimally invasive type of CXPA and increasing as the tumor becomes frankly invasive. Furthermore, we may also conclude that in CXPA with a myoepithelial component, desmoplasia is very rare.     

缬沙坦抑制人类肾小管上皮细胞转分化的初步研究

目的：探讨血管紧张素ⅡⅠ型受体拮抗剂缬沙坦（ｖａｌｓａｒｔａｎ,Ｖａｌ）在人类肾小管上皮细胞系（ＨＫＣ）转分化中的作用。方法将培养的ＨＫＣ细胞分为（１）无血清培养培养对照组;（２）阳性对照组（ＭＣＰ－１＋ＡＡＩ组）：培养液中加入马兜铃酸－Ｉ（ＡＡＩ）和单核细胞趋化蛋白－１）ＭＣＰ－１）：（３）Ｖａｌ组：培养液中加入Ｖａｌ;（４）ＭＣＰ－１＋ＡＡＩ＋Ｖａｌ组。应用间接酶标免疫组织化学方法（ＩＥＩ）检