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Valve interstitial cell phenotypes and signaling pathways involved with canine myxomatous degenerative mitral valve disease

dc.contributor.authorDisatian, Sirilak, author
dc.contributor.authorOrton, E. Christopher, advisor
dc.date.accessioned2024-03-13T19:26:12Z
dc.date.available2024-03-13T19:26:12Z
dc.date.issued2008
dc.description.abstractMyxomatous mitral valve disease is a common heart disease of dogs that is similar to myxomatous mitral valve disease in humans. The first hypothesis of this dissertation is that interstitial cell phenotype transformation described in human myxomatous valves also occurs in dogs with myxomatous mitral valves and correlates with disease severity. Normal and early-, intermediate-, and late-stage myxomatous canine mitral valves were examined by immunohistochemistry for cytoskeletal (vimentin, desmin, smooth muscle α-actin, smooth muscle myosin, and non-muscle myosin), collagenolytic (MMP-1, MMP-13), cell surface (CD-31, CD-45, CD-68) and proliferation (Ki-67) proteins. Normal canine mitral valve interstitial cells were positive for vimentin, but negative for α-actin, desmin, and non-muscle myosin (i.e. fibroblast phenotype). Interstitial cells from myxomatous valves showed increased positive staining for α-actin and desmin, but were negative for smooth muscle myosin (i.e. myofibroblast phenotype). Positive cells first appeared as clusters in the subendocardial region of the lamina atrialis and extended into deeper layers with increasing severity. Interstitial cells from myxomatous valves showed positive staining for non-muscle myosin (i.e. activated mesenchymal cell phenotype). Positive staining cells increased with disease severity and were dispersed throughout the valve layers. Expression of MMP-1 and MMP-13 correlated with disease severity. Interstitial cellularity increased in degenerative valves however Ki-67 staining was mildly increased. In conclusion, two patterns of interstitial cell phenotype transformation were identified in dogs with myxomatous mitral valve disease and both correlated with disease severity.
dc.description.abstractMyxomatous mitral valve disease in dogs shares similar pathological lesions to serotonin induced heart valve disease in humans. The second hypothesis of this dissertation is that serotonin and transforming growth factor β1 (TGFβ1) signaling play a role in canine myxomatous mitral valve disease. Septal mitral valve leaflets from dogs affected by late-stage myxomatous disease and normal dogs were collected. Immunohistochemistry and Western blotting were performed to determine the expression of target proteins involved in serotonin and TGFβ1 signaling in canine normal and myxomatous mitral valves. Immuohistochemistry and Western blotting demonstrated the up-regulation of 5HT2B receptor, phosphorylated ERK1/2, and TGFβ1 receptor I and II, latent TGFβ1 and tryptophan hydroxylase 1 (TPH1) in myxomatous valves whereas the expression of serotonin transporter (SERT) was down-regulated in myxomatous valves. In conclusion, serotonin and TGFβ1 signaling are associated with canine myxomatous mitral valve disease. This study provides preliminary data for further studies investigating exact roles of these signaling transduction pathways in pathogenesis of myxomatous mitral valve disease in dogs.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierETDF_Disatian_2008_3332723.pdf
dc.identifier.urihttps://hdl.handle.net/10217/237687
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.rights.licensePer the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users.
dc.subjectcanine
dc.subjectmyxomatous degenerative mitral valve disease
dc.subjectserotonin
dc.subjectvalve interstitial cells
dc.titleValve interstitial cell phenotypes and signaling pathways involved with canine myxomatous degenerative mitral valve disease
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineClinical Sciences
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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