Integrin-Focal Adhesion Coupling and Substrate Stiffness Affect Smooth Muscle Alpha Actin Expression in Fibroblasts

Author(s):  
Alison K. Schroer ◽  
W. David Merryman

Fibroblast cells play a key role in producing and maintaining connective tissue throughout the body. The ability of these cells to differentiate into a more active myofibroblastic phenotype is important during development and wound healing, but prolonged myofibroblast activation can lead to overproduction of extracellular matrix proteins and stiffening of the surrounding tissue. This stiffening can cause heightened differentiation of neighboring fibroblast through force transduction pathways and can lead to detrimental fibrotic pathologies in many organ systems. Atherosclerosis, interstitial lung disease, cirrhosis and heart valve disease are fibrotic diseases that cause significant cost and mortality in our society. Understanding the processes by which cells sense and respond to substrate stiffness is crucial to the treatment of connective tissue diseases. One primary indicator of the myofibroblastic phenotype is the production of α smooth muscle actin (αSMA) bundles called stress fibers which help transmit stress inside the cell and increases the contractility of the cells and their surrounding tissue [1].

1997 ◽  
Vol 33 (8) ◽  
pp. 622-627 ◽  
Author(s):  
M. Reza Ghassemifar ◽  
Roy W. Tarnuzzer ◽  
Nasser Chegini ◽  
Erkki Tarpila ◽  
Gregory S. Schultz ◽  
...  

1998 ◽  
Vol 17 (4) ◽  
pp. 449-463 ◽  
Author(s):  
John A. Todhunter ◽  
Michael G. Farrow

Whether the constellation of various symptoms reported in various case-study reports on some patients who have had augmentation mammoplasty with silicone implants reflects a distinct, novel “silicone syndrome”or disease is important to settingproper endpoints for the epidemiological study of this patient population. To date, epidemiology studies on breast implant patients have focused on end-points which are typical of connective tissue disease, rheumatoid disease, and/ or autoimmune disorders. The consensus at this time, as was recently stated in a paper authored by Food and Drug Administration (FDA) personnel, is that the weight of the evidence from existing epidemiology studies is that silicone breast implants do not appreciably, if at all, increase the risk of these types of diseases. Critics of the epidemiology database have countered that had the analysis of association in these studies been done for a “silicone syndrome,” as opposed to the disease types which were analyzed, an association between silicone breast implantation and increased risk of “silicone syndrome” would have been observed. In the present analysis, this question is approached from two directions: First, the available single or multi-patient case reports available in the open literature were evaluated. The objective was to define those symptoms/ complaints that were reported in all studies or in at least 50% of the patients reported and to assign frequency distributions to individual symptoms or complaints reported in breast implant patients presenting for various complaints. By definition, if a “silicone syndrome” exists, then it can only be characterized by those symptoms or complaints which appear with regular frequency in patients so afflicted. Second, the symptoms or complaints which were used as criteria in the existing epidemiology studies were correlated with their frequency of occurrence among single or multi-patient case-reported breast implant patients. The working hypothesis in this present study is that if the number of “silicone syndrome” symptoms or complaints that also are symptoms of the existing epidemiology endpoints is large, then a distinct “silicone syndrome” is not likely to exist, and it can be concluded that existing epidemiology studies have adequately addressed the relevant issues. Also, to the extent that the frequency of symptom occurrence in “silicone syndrome” is similar to the distribution seen for known connective tissue, rheumatoid, and/ or autoimmune diseases, this will then add to the weight of evidence that no distinct “silicone syndrome” needs be postulated. Conversely, if a different set of symptoms or complaints occurs in silicone breast-implanted patients than is seen in patients with connective tissue diseases, this will argue that a distinct syndrome may exist. In the present study, the more recent suggestion that silicone may be broken down to silica in the body, and evidence for and against this suggestion are also discussed. The present analysis does not support the contention that a distinct “silicone syndrome” exists, but does support the contention that the disease endpoints used in existing epidemiology studies are adequate for examining the patient population. Also, consideration of the chemistry of silicone and its potential hydrolysis or oxidative cleavage indicates that if such reactions occur in the body at any significant rate, the product will be silicic acid, a normal and necessary constituent of the body, and not silica (i.e., silicon dioxide).


2010 ◽  
Vol 67 (12) ◽  
pp. 977-982 ◽  
Author(s):  
Aleksandra Mladenovic-Mihailovic ◽  
Zorica Mladenovic-Bogdanovic ◽  
Predrag Mitrovic ◽  
Irena Tanaskovic ◽  
Slavica Usaj-Knezevic ◽  
...  

Background/Aim. Myomas of the uterus, the most common benign tumors, have been studied for decades from the aspects of different basic and clinical disciplines. Despite this fact, their pathogenesis is still poorly understood. The aim of this study was to determine immunocytochemical characteristics of smooth muscle cells and connective tissue components of submucosal myomas of the uterus. Method. During the course of this study, 25 samples of submucosal myomas of the uterus were analyzed, all of them obtained during the surgery, after abdominal histerctomy by Aldridge. The samples were fixed in 4% formalin and embedded in paraffin. Sections of 5 ?m thickness were stained immunocytochemically using the DAKO LSAB+/HRP technique to identify ?- smooth muscle actin (?-SMA), vimentin, desmin, CD34, CD45, CD68 and PCNA (DAKO specification). Results. Our results suggest that submucosal myomas of the uterus are build-up of smooth muscle cells which are immunoreactive to ?-SMA and desmin, but also to a certain number of smooth muscle cells which are immunoreactive to ?-SMA and vimentin. Some of vimentin-immunoreactive cells also show an immunoreactivity of PCNA. In the build-up of connective stroma CD34-immunoreactive fibroblasts and neovascular formations are also present. By examining the distribution of CD45 antigen, at all the analyzed samples we observed a weak reaction. Conclusion. Submucosal myomas of the uterus are made-up of smooth muscle cells of the highly differentiated contractile phenotype (?-SMA- and desminimmunoreactivity), as well as smooth muscle cell of the synthetic phenotype which proliferate (?-SMA-, vimentin- and PCNA-immunoreactivity). In submucosal myoma of the uterus there is a significant presence of connective tissue as a result of synthetic activity of fibroblasts, which clearly differ in their immunocytochemical characteristics from smooth muscle cells of the synthetic phenotype.


2013 ◽  
Vol 6 (3) ◽  
pp. 159-171
Author(s):  
Ishita Patel ◽  
Alia Ahmed

Connective tissue diseases are a rare and diverse group of disorders that result in pathology of the connective tissues of the body. This article focuses on the systemic autoimmune connective tissue diseases, and aims to provide a practical overview of these conditions for use in primary care.


2007 ◽  
Vol 127 (5) ◽  
pp. 523-530 ◽  
Author(s):  
Kirsten N. Storch ◽  
Douglas J. Taatjes ◽  
Nicole A. Bouffard ◽  
Sarah Locknar ◽  
Nicole M. Bishop ◽  
...  

2017 ◽  
Vol 16 (2) ◽  
pp. 61-67
Author(s):  
Maria Trojanowska

Systemic sclerosis (SSc) is characterized by autoimmunity, small-vessel vasculopathy, and fibrosis causing damage in multiple organ systems. Pulmonary arterial hypertension (PAH) is a serious and often fatal complication of SSc, occurring in patients with the limited (lcSSc) and diffuse (dcSSc) forms of the disease and affecting 8% to 15% of patients.12 While pulmonary hypertension associated with connective tissue disease (CTD-PAH) has similar clinical features as idiopathic PAH, 1-year survival and freedom from hospitalization are lower in CTD-PAH.3 SSc-PAH has the worst 1-year survival rate at 82% compared with other connective tissue diseases, including systemic lupus erythematosus, mixed connective tissue disease, and rheumatoid arthritis.34 Despite the recent progress in the development of disease-targeted therapies, patients with SSc-PAH have a poorer response to treatment and a worse prognosis than other subgroups of PAH.1 Autoimmunity and prolonged vasculopathy preceding the development of clinical manifestations of SSc-PAH may play a critical role in the poorer outcome of SSc-PAH patients.1 This article will provide an overview of the recent findings related to cellular and molecular mechanisms associated with the development of PAH, with an emphasis on SSc-PAH.


Author(s):  
Ruchi Nagpal ◽  
Arvind Ahuja

Myopericytoma is a benign tumor that shows a pericytic line of differentiation. The lesion is generally located in the dermis and subcutaneous tissue and has a predilection for distal extremities, but may be found in any part of the body. We present a case of 48-year old male who came with painful swelling in right middle finger for the past 2 years. Histopathology showed proliferation of spindle-shaped cells exhibiting a hemangio-pericytomatous pattern with various sized vessels lined by flattened endothelium and surrounded by a concentric arrangement of spindle-shaped cells. Tumor cells show membranous positivity for smooth muscle actin but negative for desmin and CD 34. Hence diagnosis of intravenous myopericytoma was established.


2010 ◽  
Vol 128 (6) ◽  
pp. 360-366 ◽  
Author(s):  
Shi-Min Yuan ◽  
Hua Jing

Marfan's syndrome is an autosomal dominant condition with an estimated prevalence of one in 10,000 to 20,000 individuals. This rare hereditary connective tissue disorder affects many parts of the body. The diagnosis of Marfan's syndrome is established in accordance with a review of the diagnostic criteria, known as the Ghent nosology, through a comprehensive assessment largely based on a combination of major and minor clinical manifestations in various organ systems and the family history. Aortic root dilation and mitral valve prolapse are the main presentations among the cardiovascular malformations of Marfan's syndrome. The pathogenesis of Marfan's syndrome has not been fully elucidated. However, fibrillin-1 gene mutations are believed to exert a dominant negative effect. Therefore, Marfan's syndrome is termed a fibrillinopathy, along with other connective tissue disorders with subtle differences in clinical manifestations. The treatment may include prophylactic β-blockers and angiotensin II-receptor blockers in order to slow down the dilation of the ascending aorta, and prophylactic aortic surgery. Importantly, β-blocker therapy may reduce TGF-β activation, which has been recognized as a contributory factor in Marfan's syndrome. The present article aims to provide an overview of this rare hereditary disorder.


Sign in / Sign up

Export Citation Format

Share Document