Home About us Contact
|
Home About us Contact | ||
|
|
||
Valve Tissue (valve + tissue)
Selected AbstractsCritical Left Ventricular Outflow Tract Obstruction Due to Accessory Mitral Valve TissueECHOCARDIOGRAPHY, Issue 2 2000RAFFAELE CALABRO M.D. Left ventricular outflow tract (LVOT) obstruction due to anomalous tissue tag arising from the mitral valve is a rare congenital cardiac anomaly. It generally becomes symptomatic during the first decade of life as exercise intolerance, chest pain, or syncope at effort. To date, only a few cases of critical systemic obstruction due to isolated mitral valve anomaly in neonates have been reported. We report the case of a neonate who was a few hours old and was referred in severe clinical condition due to critical left ventricular outflow obstruction resulting from an anomalous tissue tag of mitral valve origin. [source] Periostin promotes a fibroblastic lineage pathway in atrioventricular valve progenitor cellsDEVELOPMENTAL DYNAMICS, Issue 5 2009Russell A. Norris Abstract Differentiation of prevalvular mesenchyme into valve fibroblasts is an integral step towards the development of functionally mature cardiac valves. Although clinically relevant, little is known regarding the molecular and cellular mechanisms by which this process proceeds. Genes that are regulated in a spatio-temporal pattern during valve remodeling are candidates for affecting this differentiation process. Based on its expression pattern, we have focused our studies on the role of the matricellular gene, periostin, in regulating the differentiation of cushion mesenchymal cells into valve fibroblasts. Herein, we demonstrate that periostin expression is coincident with and regulates type I collagen protein production, a major component of mature valve tissue. Adenoviral-mediated knock-down of periostin in atrioventricular mesenchyme resulted in a decrease in collagen I protein expression and aberrant induction of myocyte markers indicating an alteration in AV mesenchyme differentiation. In vitro analyses using a novel "cardiotube" assay further demonstrated that expression of periostin regulates lineage commitment of valve precursor cells. In these cells, expression of periostin and collagen I are regulated, in part, by TGF,-3. We further demonstrate that TGF,-3, through a periostin/collagen pathway, enhances the viscoelastic properties of AV cushion tissue surface tension and plays a crucial role in regulating valve remodeling. Thus, data presented here demonstrate that periostin, a TGF,-3 responsive gene, functions as a crucial mediator of chick AV valve maturation via promoting mesenchymal-to-fibroblast differentiation while blocking differentiation of alternative cell types (myocytes). Developmental Dynamics 238:1052,1063, 2009. © 2009 Wiley-Liss, Inc. [source] Insights into Serotonin Signaling Mechanisms Associated with Canine Degenerative Mitral Valve DiseaseJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2010M.A. Oyama Little is known about the molecular abnormalities associated with canine degenerative mitral valve disease (DMVD). The pathology of DMVD involves the differentiation and activation of the normally quiescent mitral valvular interstitial cell (VIC) into a more active myofibroblast phenotype, which mediates many of the histological and molecular changes in affected the valve tissue. In both humans and experimental animal models, increased serotonin (5-hydroxytryptamine, 5HT) signaling can induce VIC differentiation and myxomatous valve damage. In canine DMVD, numerous lines of evidence suggest that 5HT and related molecules such as transforming growth factor-, play a critical role in the pathogenesis of this disease. A variety of investigative techniques, including gene expression, immunohistochemistry, protein blotting, and cell culture, shed light on the potential role of 5HT in the differentiation of VIC, elaboration of myxomatous extracellular matrix components, and activation of mitogen-activated protein kinase pathways. These studies help support a hypothesis that 5HT and its related pathways serve as an important stimulus in canine DMVD. This review describes the pathological characteristics of canine DMVD, the organization and role of the 5HT pathway in valve tissue, involvement of 5HT in human and experimental models of valve disease, avenues of evidence that suggest a role for 5HT in naturally occurring DMVD, and finally, a overarching hypothesis describing a potential role for 5HT in canine DMVD. [source] Clinically and histologically silent Q fever endocarditis accidentally diagnosed by PCRCLINICAL MICROBIOLOGY AND INFECTION, Issue 2 2002B. Issartel A case of Q fever endocarditis was diagnosed in a patient with no sign of active endocarditis by performing PCR targeting eubacterial 16S rDNA on the resected mitral valve. The diagnosis was confirmed by detection of high levels of anti- Coxiella burnetti antibodies, positive immunohistologic analysis of the valve tissue with specific antibodies and culture of C. burnetti from the valve tissue. As this patient had an unexplained aggravation of valve dysfunction, we recommended routine serologic testing for C. burnetti to allow the diagnosis of Q fever endocarditis at a very early stage. [source] Differential protein expression between normal, early-stage, and late-stage myxomatous mitral valves from dogsPROTEOMICS - CLINICAL APPLICATIONS, Issue 12 2009Carla M. R. Lacerda Abstract Valvular heart disease accounts for over 20,000 deaths and 90,000 hospitalizations yearly in the United States. Myxomatous valve disease (MVD) is the most common disease of the mitral valve in humans and dogs. MVD is pathologically identical in these species and its pathogenesis is poorly understood. The objectives of this study were to (i) develop proteomic methodology suitable for analysis of extracellular matrix-rich heart valve tissues and (ii) survey over- and under-expressed proteins that could provide mechanistic clues into the pathogenesis of MVD. Normal, early-stage, and late-stage myxomatous mitral valves from dogs were studied. A shotgun proteomic analysis was used to quantify differential protein expression. Proteins were classified by function and clustered according to differential expression patterns. More than 300 proteins, with 117 of those being differentially expressed, were identified. Hierarchical sample clustering of differential protein profiles showed that early- and late-stage valves were closely related. This finding suggests that proteome changes occur in early degeneration stages and these persist in late stages, characterizing a diseased proteome that is distinct from normal. Shotgun proteome analysis of matrix-rich canine heart valves is feasible, and should be applicable to human heart valves. This study provides a basis for future investigations into the pathogenesis of MVD. [source] | |||||||||||||