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Inflammation and Cytokines in Airway Wall Remodelling
Published in Alastair G. Stewart, AIRWAY WALL REMODELLING in ASTHMA, 2020
Although fibroblasts are capable of tissue migration, their location within the airway during chronic stable asthma may well dictate their functional capacity. Although easily identified beneath the true basement membrane by electronmicroscopy,289 similar cells are found deeper within the submucosa (Figure 4). Staining of bronchial biopsies from patients with asthma with PR2D3 shows positive cells within bronchial and vascular smooth muscle, as well as a concentration below the bronchial epithelium. As much as 50% of cells express α-smooth muscle actin, indicating a proportion of myofibroblasts to be heterogeneous in phenotype with the ability to express this protein.289,295 The distribution of myofibroblasts deeper in the submucosa is reduced when compared with the subepithelial region (Figure 5).
The locomotor system
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
This tumour usually affects middle-aged and elderly people. About half of soft tissue leiomyosarcomas arise in the retroperitoneum and have a poor prognosis, with less than 30% of patients surviving 5 years. Of the remainder, most are found in the dermis or subcutaneous tissue. In keeping with other superficially situated sarcomas the prognosis for these tumours is better, with over 90% of patients with dermal tumours and 65% with subcutaneous lesions surviving 5 years. Histologically, leiomyosarcomas consist of spindle-shaped cells resembling normal smooth muscle cells, which are arranged in long interlacing fascicles. Many tumours express desmin and smooth muscle actin. The principal criterion in distinguishing malignant and benign smooth muscle tumours is the number of mitotic figures. Nuclear pleomorphism without mitotic activity may be found in leiomyomas.
Abnormalities of the Calcium Pump in Primary Hypertension
Published in Antonio Coca, Ricardo P. Garay, Ionic Transport in Hypertension: New Perspectives, 2019
Alejandro De la Sierra, Javier Sobrino, Antonio Coca
Contraction of the smooth muscle cells begins with the opening of voltage-operated and receptor-operated calcium channels, located in the cell membrane and in the sarcoplasmic reticulum. All this results in the increase of free cytosolic Ca2+ content. Calcium acts on the contractile proteins of the smooth muscle (actin and myosin) that change their spatial conformation, interacting with each other to cause the cell contraction.
Hyalocytes in proliferative vitreo-retinal diseases
Published in Expert Review of Ophthalmology, 2022
Charlotte H. Jones, Wei Gui, Ricarda G. Schumann, Stefaniya K. Boneva, Clemens A. K. Lange, Koen A. van Overdam, Toco Y. P. Chui, Richard B. Rosen, Michael Engelbert, J. Sebag
Transdifferentiation of hyalocytes into myofibroblasts appears to occur early in various vitreo-retinal disorders, including paucicellular tractional vitreo-maculopathies such as macular holes [85]. Myofibroblasts are a subset of fibroblasts distinguished by cytoplasmic aggregates of actin microfilaments forming stress bundles. Similar to smooth muscle cells, they are characterized by α-smooth muscle actin (α-SMA) immunoreactivity. When cultured on collagen lattice in vitro, human myofibroblasts were shown to generate more potent traction forces than smooth muscle cells [37,105]. In VMTS, myofibroblasts were reported to predominate the cellular composition of fibrocellular membranes [96]. Further, hyalocytes are not only believed to undergo phenotypic changes developing contractile properties, but are also capable of collagen production within the premacular cell population [98], first described by Newsome in 1976 [106] and more recently reported in a porcine hyalocyte cell line in vitro [107]. Most hyalocytes found in pathologic membranes are situated on a collagen fibril network identified as native vitreous collagen. In contrast, myofibroblast-like cells were demonstrated in masses mostly embedded in layers of newly formed collagen.
Cyclo-VEGI inhibits bronchial artery remodeling in a murine model of chronic asthma
Published in Experimental Lung Research, 2021
Kyung Hoon Kim, Jung Hur, Hwa Young Lee, Eung Gu Lee, Sook Young Lee
Six-micrometer-thick sections of lung tissues from each paraffin block were deparaffinized in xylene and rehydrated in ethanol. The sections were subjected to immunohistochemical staining for alpha-smooth muscle actin (α-SMA) to assess changes involving α-SMA area. The lung sections were incubated overnight at 4 °C with primary mouse monoclonal antibodies (Dako, High Wycombe, UK) directed against α-SMA. Immunoreactivity was detected by sequentially incubating the lung sections with a biotinylated secondary antibody, followed by peroxidase reagent (Vector Laboratories, Burlingame, CA, USA) and diaminobenzidine chromogen (Invitrogen, Carlsbad, CA, USA). Immunostained areas of α-SMA were estimated from the α-SMA-positive areas using an image processing software (Pannoramic MIDI; 3 D Histech, Budapest, Hungary). The results were expressed as the immunostained area per micrometer length of the basement membrane of the bronchioles (internal diameter, 150−200 μm) and bronchial arteries. The immunostained areas of the bronchial arteries and bronchi were measured separately using an image analysis system attached to a light microscope (BX50, Olympus, Tokyo, Japan).
Intractable cardiac inflammatory myofibroblastic tumour causing refractory right heart failure: a case report
Published in Acta Cardiologica, 2020
Irfan Veysel Duzen, Yasemin Akca, Hale Colakoglu, Mehmet Adnan Celkan, Mert Deniz Savcilioglu, Enes Alıc, Ugur Sener, Murat Sucu
A 37-year-old male patient was referred to our clinic due to refractory right-sided heart failure. Physical examination showed generalised oedema in lower extremities bilaterally, ascites and hepatomegaly. Electrocardiography showed sinus tachycardia. A confluencing tumour-like mass occupying the right atrium and ventricle with restricted motion of the tricuspid valve and pulmonary valve was observed on echocardiography (Figure 1). CT scan confirmed the heterogeneous mass involving the lateral wall of the right atrium, tricuspid valve up to the right ventricle that caused obstruction at both tricuspid and pulmonary artery levels (Figure 2). He was referred to cardiovascular surgery. During surgery, incomplete resection of the tumour tissue could be achieved which was attached to the heart, totally occluding the tricuspid valve (Figure 3). He was admitted to the intensive care unit and died postoperatively due to right ventricular dysfunction, hypotension and cardiogenic shock. Histological examination of the tumour sample demonstrated a lesion which was partly attached to the striated muscle fibres and partly invading the striated muscle cells and composed of many chronic active inflammatory cells and spindle cells with oval nuclei and distinct nucleoli, rich in inflammatory cells embedded in a myxoid matrix (Figure 4). Obvious pleomorphism, atypical mitosis and necrosis were absent. Immunohistochemical staining revealed positive staining with smooth muscle actin and vimentin. A cardiac inflammatory myofibroblastic tumour (IMFT) was diagnosed based on these findings.