Age-Related Collagen and Elastin Content of Human Heart Valves

Bashey, Reza I.; Torii, Shinichiro; Angrist, Alfred

doi:10.1093/geronj/22.2.203

Cited by 83 publications

(47 citation statements)

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“…19 Human valve cusps are Ϸ43% to 55% collagen (predominantly type I but also some type III, as measured in bovine valve) 20 and 11% elastin (dry weight ratio); together they comprise Ϸ80% of total valvular protein. 21 The quantity, quality, and architecture of the valvular ECM, particularly collagen, elastin, and glycosaminoglycans, are the major determinants of not only the cyclical functional mechanics over the second-to-second periodicity of the cardiac cycle, as described above, but also the long-term (lifetime) durability of a valve. The macroscopic mechanical stimuli, both shear and solid stresses that occur during normal valvular function, are translated into microscopic forces that affect biological phenomena at the tissue and cellular levels.…”

Section: The Functional Role Of Valvular Extracellular Matrixmentioning

confidence: 99%

Evolving Concepts of Cardiac Valve Dynamics

2008

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Abstract-Considerable progress has been made in recent years toward elucidating a conceptual framework that integrates the dynamic functional structure, mechanical properties, and pathobiological behavior of the cardiac valves. This communication reviews the evolving paradigm of a continuum of heart valve structure, function, and pathobiology and explores its implications. Specifically, we discuss (1) the interactions of valve biology and biomechanics (eg, correlations of function with structure at the cell, tissue, and organ levels and mechanical considerations, development, endothelial cell and interstitial cell biology, extracellular matrix biology, homeostasis, and adaptation to environmental change); (2) Key Words: aortic valve Ⅲ mitral valve Ⅲ pathology Ⅲ prosthesis Ⅲ tissue engineering I mportant conceptual advances, new data, and evolution in our understanding and application of the principles underlying the dynamic functional, biological, and mechanical behavior of the cardiac valves have occurred in recent years. Research in heart valve biology and disease has been enabled by the availability of cultures of heart valve cells, computational methodology, the design and use of in vitro and in vivo experimental systems that model elements of valve biological and pathobiological activity, and targeted study of normally functioning and pathological native and substitute human valves. Collectively, these developments have facilitated a growing understanding of how shortand long-term biomechanical valve function at the organ level relates to tissue and cell structure and normal valve function, elucidated the pathological anatomy and mechanisms of valvular dysfunction, fostered improvements in tissue heart valve substitutes and surgical repairs, and informed innovative approaches to heart valve tissue engineering and regeneration. [1][2][3][4] In this communication, we highlight key recent insights into heart valve function and dysfunction and their implications for the prevention, diagnosis, and treatment of clinical heart valve disease, currently and in the future. The heart valves are tissue structures whose motions are driven by mechanical forces exerted by the surrounding blood and heart. The ability of the valves to permit unobstructed forward flow depends on the mobility, pliability, and structural integrity of their leaflets (in the TV and MV) and cusps (in the PV and AV).The individual AV cusps attach to the aortic wall in a crescentic (or semilunar) fashion, ascending to the commissures (where adjacent cusps come together at the aorta) and descending to the basal attachment of each cusp to the aortic wall. Behind the cusps are dilated pockets in the aortic root, called sinuses of Valsalva, which bulge with each ejection of blood. The AV cusps and their respective sinuses are named for their relationship to the coronary artery ostia that arise from them, normally a left, a right, and a noncoronary (cusp and associated sinus). In the middle of the free edge of each cusp on the ventricular surface is a ...

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Section: The Functional Role Of Valvular Extracellular Matrixmentioning

confidence: 99%

Evolving Concepts of Cardiac Valve Dynamics

2008

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“…13 Interstitial collagenases mediate the initial step of collagen degradation by breakdown of the native helix of the fibrillar collagen network (type I is most abundant, comprising Ϸ70% of the total collagen in valves). 20 These fragments then become accessible to the other proteases, such as gelatinases, which further catabolize collagen. 21 Cathepsins S and K are also involved in ECM remodeling, particularly elastin.…”

Section: Role and Mechanisms Of Matrix Remodelling In Myxomatous Mitrmentioning

confidence: 99%

Activated Interstitial Myofibroblasts Express Catabolic Enzymes and Mediate Matrix Remodeling in Myxomatous Heart Valves

Rabkin

Aikawa²,

Stone³

et al. 2001

Circulation

537

490

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Background-The mechanisms of extracellular matrix changes accompanying myxomatous valvular degeneration are uncertain. Methods and Results-To test the hypothesis that valvular interstitial cells mediate extracellular matrix degradation in myxomatous degeneration by excessive secretion of catabolic enzymes, we examined the functional characteristics of valvular interstitial cells in 14 mitral valves removed for myxomatous degeneration from patients with mitral regurgitation and in 11 normal mitral valves obtained at autopsy. Immunohistochemical staining assessed (1) cell phenotype using antibodies to ␣-actin (microfilaments), vimentin and desmin (intermediate filaments), smooth muscle myosin (SM1), and SMemb (a nonmuscle myosin produced by activated mesenchymal cells) and (2) the expression of proteolytic activity using antibodies to collagenases (matrix metalloproteinase [MMP]-1, MMP-13), gelatinases (MMP-2, MMP-9), cysteine endoproteases (cathepsin S and K), and interleukin-1␤, a cytokine that can induce secretion of proteolytic enzymes. Although interstitial cells in normal valves stained positively for vimentin, but not ␣-actin or desmin, cells in myxomatous valves contained both vimentin and ␣-actin or desmin (characteristics of myofibroblasts). Moreover, cells in myxomatous valves strongly expressed SMemb, MMPs, cathepsins, and interleukin-1␤, which were weakly stained in controls. Nevertheless, interstitial cells in both groups strongly expressed procollagen-I mRNA (in situ hybridization), suggesting preserved ability to synthesize collagen in myxomatous valves. Conclusions-Interstitial cells in myxomatous valves have features of activated myofibroblasts and express excessive levels of catabolic enzymes, without altered levels of interstitial collagen mRNA. We conclude that valvular interstitial cells regulate matrix degradation and remodeling in myxomatous mitral valve degeneration.

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“…Todos os tecidos e órgãos apresentam um ciclo vital, que modifica sua estrutura e função em decorrência do envelhecimento, parede arterial, massa corporal, órgãos do sistema reprodutor, músculos, fígado, moléculas de colágeno e tecido elástico (Verzár 1956, 1960, Schaub 1964, Bashey et al 1967, Zwolinski et al 1976). Imayama & Braverman, 1989, observaram que na pele o envelhecimento faz com que as fibras elásticas se tornem progressivamente tortuosas e com superfície irregular, as tortuosidades significariam que as fibras foram estiradas e a seguir perderam a elasticidade, determinando, como conseqüência, dobras ou rugas.…”

Section: Discussionunclassified

“…Nosso trabalho analisou e quantificou o colágeno tipo I e III, pois são os dois tipos predominantes em envoltórios conjuntivos que mantêm a arquitetura e servem de proteção a determinados órgãos e vísceras. Na literatura, foi verificado que as fibras colágenas podem aumentar ou se manter estáveis, assim como diminuírem com o envelhecimento, dependendo da região ou espécie analisada (Schaub 1964, Verzár 1956, Bashey et al 1967, Zwolinski et al 1976, Ding et al 1998, Hamann et al 1998, Ferreira 2005.…”

Section: Discussionunclassified

Histomorfometria das meninges encefálicas de ratos Wistar em diferentes faixas etárias

et al. 2010

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Pesquisa Veterinária Brasileira 30(11):996-1002. Curso de Ciências Biológicas, Universidade Federal de Goiás, Unidade Jatobá, Setor Parque Industrial, Jataí, GO 75800-000, Brazil. E-mail: kpereira@usp.brThe development of the nervous system is very complex and there are few studies about the organization of the brain envoltories related to the encephalus growing. Using the rat as an animal model, it was proposed to evaluate the several structural aspects of paquimeninge and leptomeninge in different ages. It was used 4 groups of different ages and processed according to the techniques of the light and transmission microscopy. It was verified that the adult rats present a higher area of collagen fibers of type I and III, if compared to the others groups. It was found that, the collagen fibers of type III occupy, in all analyzed groups, a higher area when compared to type I fibers. The results reveal that the Weigert Oxona's staining, which shows elastics, elauninics, and oxitalanics fibers, showed a statistically difference when compared to the Weigert's staining and Verhoeff's staining that show elauninics and elastics fibers, respectively. The ultra-structural aspects demonstrated the presence of many fibroblasts and mitochondria in the paquimeninge and also in the leptomeninges of the neonats and adults groups, indicating the high cellular activity and consequently, an intense formation of conjunctive tissue. As collagen fibers of type III acting on the structural maintenance of delicate and expansive tissues, the study shows that the function of the encephalic meninges are not only related to the to resistance to tractions and tensions that the encephalus is subjected. But also the function related to the distensibility of the meningeos and brain vases according to the sanguineous apport in several specific functions of the nervous system. Aceito para publicação em 24 de agosto de 2010.

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Age-Related Collagen and Elastin Content of Human Heart Valves

Cited by 83 publications

References 0 publications

Evolving Concepts of Cardiac Valve Dynamics

Evolving Concepts of Cardiac Valve Dynamics

Activated Interstitial Myofibroblasts Express Catabolic Enzymes and Mediate Matrix Remodeling in Myxomatous Heart Valves

Histomorfometria das meninges encefálicas de ratos Wistar em diferentes faixas etárias

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