Collagen Synthesis Is Upregulated in Mitral Valves Subjected to Altered Stress

Quick, David W.; Kunzelman, Karyn S.; Kneebone, James M.; Cochran, Richard P.

doi:10.1097/00002480-199743030-00011

Cited by 4 publications

(3 citation statements)

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“…Numerical simulations of the mitral valve components have been performed to examine the role of different valvular parts; for instance the role of the chordate tendineae [28] or the effect of annular dilation and correction [29].…”

Section: Progress and Trend Of Nature Heart Valve Simulationmentioning

confidence: 99%

Numerical Simulation of the Dynamics of Heart Valves: A Literature Review

Zhong

Zeng

Xiao

et al. 2013

AMM

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Imaging techniques allow the visualization of the heart valves, but do not yields any information regarding the load applied to the heart valve information that provides key clues to the cause of valve deterioration. Numerical simulation, which is able to replicate and understand the dynamics of the valve, would benefit studies on heart valves surgical repair and prostheses design. Modeling and simulation of heart valves dynamics is a challenging biomechanical problem. Many researchers have taken various approaches to model the heart valve. But systematical categorization and development tendency of their research have never been discussed before. This paper reviews their models and divides them into wet models or dry models, in the light of whether considering blood flow and valve interaction. These simulations also can be categorized as native heart valve or artificial heart valve simulation by a different model prototype. The critical issues for future research are presented.

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Section: Progress and Trend Of Nature Heart Valve Simulationmentioning

confidence: 99%

Numerical Simulation of the Dynamics of Heart Valves: A Literature Review

Zhong

Zeng

Xiao

et al. 2013

AMM

View full text Add to dashboard Cite

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“…Quick and Kunzelman reported that MV leaflets with abundant fibroblast-like valve interstitial cells have altered collagen concentration when subjected to mechanical strain. 7,8 Grande-Allen et al found that in heart failure patients with chronic MV tethering and systemic inflammation, the leaflets are significantly thicker and stiffer. 9,10 In a more recent series of investigations, Dal-Bianco et al demonstrated that tethering and inflammation have a dual mode effect on activating MV interstitial cells.…”

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confidence: 99%

Pathological Remodeling of Mitral Valve Leaflets from Unphysiologic Leaflet Mechanics after Undersized Mitral Annuloplasty to Repair Ischemic Mitral Regurgitation

Sielicka

Sarin

Shi

et al. 2018

JAHA

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Background Undersized ring annuloplasty is a commonly used surgical repair for ischemic mitral regurgitation, in which annular downsizing corrects regurgitation, but alters valve geometry and elevates tissue stresses. In this study, we investigated if unphysiological leaflet kinematics after annuloplasty might cause pathogenic biological remodeling of the mitral valve leaflets, and if preserving physiologic leaflet kinematics with a better technique can moderate such adverse remodeling. Methods and Results Twenty‐nine swine were induced with ischemic mitral regurgitation, and survivors were assigned to groups: 7 underwent annuloplasty, 12 underwent annuloplasty with papillary‐muscle approximation, 6 underwent papillary‐muscle approximation, and 3 were sham controls. Pre‐and post‐surgery leaflet kinematics were measured, and valve tissue was explanted after 3 months to assess biological changes. Anterior leaflet excursion was unchanged across groups, but persistent tethering was observed with annuloplasty. Posterior leaflet was vertically immobile after annuloplasty, better mobile with the combined approach, and substantially ( P =0.0028) mobile after papillary‐muscle approximation. Procollagen‐1 was higher in leaflets from annuloplasty compared with the other groups. Heat shock protein‐47 and lysyl oxidase were higher in groups receiving annuloplasty compared with sham. α‐ SMA was elevated in leaflets from animals receiving an annuloplasty, indicating activation of quiescent valve interstitial cells, paralleled by elevated transforming growth factor‐β expression. Conclusions This is the first study to demonstrate that surgical valve repairs that impose unphysiological leaflet mechanics have a deleterious, pathological impact on valve biology. Surgeons may need to consider restoring physiologic leaflet stresses as well as valve competence, while also exploring pharmacological methods to inhibit the abnormal signaling cascades.

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“…To determine whether uneven clipping plays a role in MR recurrence, we investigated the effect of uneven clipping on leaflet stress, which is implicated in repair failure. Leaflets excised after failed MitraClip show significant tissue damage, including large perforations; furthermore, in vitro studies have shown that increased leaflet stress alters collagen and proteoglycan synthesis, resulting in leaflet thickening and increased compliance . Leaflet stress after uneven clip application has not been previously studied.…”

mentioning

confidence: 99%