scholarly journals Immune Privilege of Heart Valves

2021 ◽  
Vol 12 ◽  
Author(s):  
Morgan Ashley Hill ◽  
Jennie H. Kwon ◽  
Brielle Gerry ◽  
William A. Hardy ◽  
Olivia Agata Walkowiak ◽  
...  
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Clinical Evidence ◽  
Corneal Transplantation ◽  
Immune Privilege ◽  
Collateral Damage ◽  
Vital Function ◽  
Regenerative Capacity ◽  
The Brain ◽  
Evolutionary Fitness

Immune privilege is an evolutionary adaptation that protects vital tissues with limited regenerative capacity from collateral damage by the immune response. Classical examples include the anterior chamber of the eye and the brain. More recently, the placenta, testes and articular cartilage were found to have similar immune privilege. What all of these tissues have in common is their vital function for evolutionary fitness and a limited regenerative capacity. Immune privilege is clinically relevant, because corneal transplantation and meniscal transplantation do not require immunosuppression. The heart valves also serve a vital function and have limited regenerative capacity after damage. Moreover, experimental and clinical evidence from heart valve transplantation suggests that the heart valves are spared from alloimmune injury. Here we review this evidence and propose the concept of heart valves as immune privileged sites. This concept has important clinical implications for heart valve transplantation.

scholarly journals Fourier transform infrared spectroscopy coupled with machine learning classification for identification of oxidative damage in freeze-dried heart valves

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dejia Liu ◽  
Sükrü Caliskan ◽  
Bita Rashidfarokhi ◽  
Harriëtte Oldenhof ◽  
Klaus Jung ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Oxidative Damage ◽  
Fourier Transform Infrared Spectroscopy ◽  
Heart Valve ◽  
Freeze Drying ◽  
Heart Valves ◽  
Fourier Transform Infrared ◽  
Freeze Dried ◽  
Nbt Staining

AbstractFreeze-drying can be used to ensure off-the-shelf availability of decellularized heart valves for cardiovascular surgery. In this study, decellularized porcine aortic heart valves were analyzed by nitroblue tetrazolium (NBT) staining and Fourier transform infrared spectroscopy (FTIR) to identify oxidative damage during freeze-drying and subsequent storage as well as after treatment with H2O2 and FeCl3. NBT staining revealed that sucrose at a concentration of at least 40% (w/v) is needed to prevent oxidative damage during freeze-drying. Dried specimens that were stored at 4 °C depict little to no oxidative damage during storage for up to 2 months. FTIR analysis shows that fresh control, freeze-dried and stored heart valve specimens cannot be distinguished from one another, whereas H2O2- and FeCl3-treated samples could be distinguished in some tissue section. A feed forward artificial neural network model could accurately classify H2O2 and FeCl3 treated samples. However, fresh control, freeze-dried and stored samples could not be distinguished from one another, which implies that these groups are very similar in terms of their biomolecular fingerprints. Taken together, we conclude that sucrose can minimize oxidative damage caused by freeze-drying, and that subsequent dried storage has little effects on the overall biochemical composition of heart valve scaffolds.

Dialdehyde pectin-crosslinked and hirudin-loaded decellularized porcine pericardium with improved matrix stability, enhanced anti-calcification and anticoagulant for bioprosthetic heart valves

2021 ◽  
Author(s):  
Mengyue Hu ◽  
Xu Peng ◽  
Yang Zhao ◽  
Xiaoshuang Yu ◽  
Can Cheng ◽  
...  
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Heart Valve Diseases ◽  
Bioprosthetic Heart Valves ◽  
Matrix Stability ◽  
Transcatheter Valve ◽  
Valve Diseases ◽  
Porcine Pericardium

To conveniently and effectively cure heart valve diseases or defects, combining with transcatheter valve technology, bioprosthetic heart valves (BHVs) originated from the decellularized porcine pericardium (D-PP) have been broadly used...

scholarly journals Inflammatory Regulation of Valvular Remodeling: The Good(?), the Bad, and the Ugly

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Gretchen J. Mahler ◽  
Jonathan T. Butcher
Keyword(s):  
Heart Valve ◽  
Cell Biology ◽  
Heart Valves ◽  
Valve Disease ◽  
Heart Valve Disease ◽  
Inflammatory Signaling ◽  
Current State ◽  
Valve Remodeling ◽  
Inflammatory Regulation ◽  
Key Questions

Heart valve disease is unique in that it affects both the very young and very old, and does not discriminate by financial affluence, social stratus, or global location. Research over the past decade has transformed our understanding of heart valve cell biology, yet still more remains unclear regarding how these cells respond and adapt to their local microenvironment. Recent studies have identified inflammatory signaling at nearly every point in the life cycle of heart valves, yet its role at each stage is unclear. While the vast majority of evidence points to inflammation as mediating pathological valve remodeling and eventual destruction, some studies suggest inflammation may provide key signals guiding transient adaptive remodeling. Though the mechanisms are far from clear, inflammatory signaling may be a previously unrecognized ally in the quest for controlled rapid tissue remodeling, a key requirement for regenerative medicine approaches for heart valve disease. This paper summarizes the current state of knowledge regarding inflammatory mediation of heart valve remodeling and suggests key questions moving forward.

scholarly journals Regeneration, Plasticity, and Induced Molecular Programs in Adult Zebrafish Brain

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mehmet Ilyas Cosacak ◽  
Christos Papadimitriou ◽  
Caghan Kizil
Keyword(s):  
Neural Plasticity ◽  
Molecular Mechanisms ◽  
Clinical Settings ◽  
Regenerative Capacity ◽  
Zebrafish Brain ◽  
Aquatic Vertebrates ◽  
Neural Stem Progenitor Cells ◽  
Set Up ◽  
Regenerative Therapies ◽  
The Brain

Regenerative capacity of the brain is a variable trait within animals. Aquatic vertebrates such as zebrafish have widespread ability to renew their brains upon damage, while mammals have—if not none—very limited overall regenerative competence. Underlying cause of such a disparity is not fully evident; however, one of the reasons could be activation of peculiar molecular programs, which might have specific roles after injury or damage, by the organisms that regenerate. If this hypothesis is correct, then there must be genes and pathways that (a) are expressed only after injury or damage in tissues, (b) are biologically and functionally relevant to restoration of neural tissue, and (c) are not detected in regenerating organisms. Presence of such programs might circumvent the initial detrimental effects of the damage and subsequently set up the stage for tissue redevelopment to take place by modulating the plasticity of the neural stem/progenitor cells. Additionally, if transferable, those “molecular mechanisms of regeneration” could open up new avenues for regenerative therapies of humans in clinical settings. This review focuses on the recent studies addressing injury/damage-induced molecular programs in zebrafish brain, underscoring the possibility of the presence of genes that could be used as biomarkers of neural plasticity and regeneration.

scholarly journals Comparison of Heart Valve Circumference Examined Before and After 10% Formalin Fixation

2021 ◽  
Vol 73 (7) ◽  
pp. 478-484
Author(s):  
Watcharit Anantakal ◽  
◽  
Somboon Thamtakerngkit ◽  
Vijarn Vachirawongsakorn ◽  
◽  
...  
Keyword(s):  
Mitral Valve ◽  
Aortic Valve ◽  
Heart Valve ◽  
Tricuspid Valve ◽  
Heart Valves ◽  
Formalin Fixation ◽  
Pulmonic Valve ◽  
Fresh State ◽  
Before And After ◽  
Formalin Fixed

Objective: To compare the heart valve circumference before and after 10% formalin fixation. Materials and Methods: The study analyzed 63 Thai human cadaveric hearts. Each heart valve circumference was separately measured in the fresh state by specifically designed equipment. After that, the hearts were fixed in 10% formalin for 3 days. Then each heart valve circumference was measured by the same equipment and by the thread and ruler technique. The results were analyzed using SPSS package to find the association between the heart valve circumference before and after formalin fixation. Results: This study showed that the average circumferences of the heart valve measured in the fresh state were 13.329 cm in the tricuspid valve, 10.617 cm in the mitral valve, 8.416 cm in the pulmonic valve, and 7.122 cm in the aortic valve. The average circumferences of the heart valve measured after 10% formalin fixation were 11.019 cm in the tricuspid valve, 8.714 cm in the mitral valve, 6.751 cm in the pulmonic valve, and 6.089 cm in the aortic valve. The average ratios of the heart valve circumference measured fresh and after 10% formalin fixation were 0.8267 in the tricuspid valve, 0.8235 in the mitral valve, 0.8050 in the pulmonic valve, and 0.8573 in the aortic valve. There were significant differences in the heart valve circumference between the fresh state and after formalin fixation (p < 0.001). Conclusion: This study revealed important information on the dimensional changes of all the formalin-fixed heart valves. We found that the heart valve shrank after formalin fixation, with the formalin-fixed hearts an estimated 0.8 times smaller than the fresh cadaveric hearts.

scholarly journals History of the use of autologous materials in aortic valve surgery

2021 ◽  
Vol 25 (3) ◽  
pp. 106
Author(s):  
R. N. Komarov ◽  
A. O. Simonyan ◽  
I. A. Borisov ◽  
V. V. Dalinin ◽  
A. M. Ismailbaev ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Heart Valve ◽  
Heart Valves ◽  
Surgical Techniques ◽  
Valve Surgery ◽  
Aortic Valve Surgery ◽  
Short Service Life ◽  
Wide Range ◽  
Valve Reconstruction ◽  
History Of

<p>Various types of autologous materials are used in heart valve surgery, particularly the aortic valve, and this article describes their historical development. The evolution of the use of various autogenous tissues, such as the aortic wall, fascia lata of the thigh, pericardium and others is described and discussed in detail. This paper presents the results of experimental and clinical publications devoted to the surgical techniques and the outcomes of heart valve reconstruction using such materials. The negative aspects of the use of a wide range of autografts are discussed, including the short service life and low strength, which led to declining interest in this group of reconstructive interventions. The method for treating the autopericardium with glutaraldehyde, proposed in 1986 by C.S. Love, J.W. Love and colleagues, raised the use of autologous materials in the reconstruction of heart valves to a new level, allowing surgeons to strengthen the autopericardial flaps and increase resistance to hemodynamic stress. Many surgeons, their interest in such treatment methods increased by this discovery, then reported their observations and further developed ways of using the treated autopericardium in aortic valve surgery. Particularly, the method of neocuspidisation of the aortic valve, introduced into wide practice by M.G. Duran and S. Ozaki, has become the quintessential reconstructive valve surgery involving the use of autologous materials.</p><p>Received 14 March 2021. Revised 26 April 2021. Accepted 27 April 2021.</p><p><strong>Funding:</strong> The study did not have sponsorship.</p><p><strong>Conflict of interest:</strong> The authors declare no conflicts of interests.</p><p><strong>Contribution of the authors</strong><br />Conception and study design: A.O. Simonyan, A.M. Ismailbaev<br />Drafting the article: A.O. Simonyan, A.M. Ismailbaev, N.O. Kurasov, M.I. Tcheglov<br />Critical revision of the article: R.N. Komarov, V.V. Dalinin, I.A. Borisov<br />Final approval of the version to be published: R.N. Komarov, A.O. Simonyan, I.A. Borisov, V.V. Dalinin, A.M. Ismailbaev, N.O. Kurasov, M.I. Tcheglov</p>

TTK Chitra tilting disc heart valve model TC2: An assessment of fatigue life and durability

2017 ◽  
Vol 231 (8) ◽  
pp. 758-765 ◽  
Author(s):  
NN Subhash ◽  
Adathala Rajeev ◽  
Sreedharan Sujesh ◽  
CV Muraleedharan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Heart Valve ◽  
Life Prediction ◽  
Heart Valves ◽  
Failure Modes ◽  
Fatigue Life Prediction ◽  
Element Analysis ◽  
Valve Model

Average age group of heart valve replacement in India and most of the Third World countries is below 30 years. Hence, the valve for such patients need to be designed to have a service life of 50 years or more which corresponds to 2000 million cycles of operation. The purpose of this study was to assess the structural performance of the TTK Chitra tilting disc heart valve model TC2 and thereby address its durability. The TC2 model tilting disc heart valves were assessed to evaluate the risks connected with potential structural failure modes. To be more specific, the studies covered the finite element analysis–based fatigue life prediction and accelerated durability testing of the tilting disc heart valves for nine different valve sizes. First, finite element analysis–based fatigue life prediction showed that all nine valve sizes were in the infinite life region. Second, accelerated durability test showed that all nine valve sizes remained functional for 400 million cycles under experimental conditions. The study ensures the continued function of TC2 model tilting disc heart valves over duration in excess of 50 years. The results imply that the TC2 model valve designs are structurally safe, reliable and durable.

scholarly journals Adverse Hemodynamic Conditions Associated with Mechanical Heart Valve Leaflet Immobility

2018 ◽  
Vol 5 (3) ◽  
pp. 74 ◽  
Author(s):  
Fardin Khalili ◽  
Peshala Gamage ◽  
Richard Sandler ◽  
Hansen Mansy
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Computational Study ◽  
Cell Damage ◽  
Mechanical Heart Valve ◽  
Flow Characteristics ◽  
Maximal Velocity ◽  
Valve Dysfunction ◽  
Promising Tool ◽  
Artificial Heart Valves

Artificial heart valves may dysfunction, leading to thrombus and/or pannus formations. Computational fluid dynamics is a promising tool for improved understanding of heart valve hemodynamics that quantify detailed flow velocities and turbulent stresses to complement Doppler measurements. This combined information can assist in choosing optimal prosthesis for individual patients, aiding in the development of improved valve designs, and illuminating subtle changes to help guide more timely early intervention of valve dysfunction. In this computational study, flow characteristics around a bileaflet mechanical heart valve were investigated. The study focused on the hemodynamic effects of leaflet immobility, specifically, where one leaflet does not fully open. Results showed that leaflet immobility increased the principal turbulent stresses (up to 400%), and increased forces and moments on both leaflets (up to 600% and 4000%, respectively). These unfavorable conditions elevate the risk of blood cell damage and platelet activation, which are known to cascade to more severe leaflet dysfunction. Leaflet immobility appeared to cause maximal velocity within the lateral orifices. This points to the possible importance of measuring maximal velocity at the lateral orifices by Doppler ultrasound (in addition to the central orifice, which is current practice) to determine accurate pressure gradients as markers of valve dysfunction.

Large Displacement Flexural Properties of Tissue Engineered Heart Valve Scaffolds

2000 ◽  
Author(s):  
Michael S. Sacks ◽  
Sanjay Kaushal ◽  
John E. Mayer
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Critical Test ◽  
Bioprosthetic Heart Valves ◽  
Property Evaluation ◽  
Fundamental Information ◽  
Tissue Engineered Heart Valve ◽  
Valve Prostheses ◽  
Tissue Engineered Heart Valves

Abstract The need for improved heart valve prostheses is especially critical in pediatric applications, where growth and remodeling are essential. Tissue engineered heart valves (TEHV) have functioned in the pulmonary circulation of growing lambs for up to four months [1], and thus can potentially overcome limitations of current bioprosthetic heart valves. Despite these promising results, significant questions remain. In particular, the role of scaffold mechanical properties in optimal extra-cellular matrix development, as well as TEHV durability, are largely unexplored. We have previously demonstrated flexure testing as a sensitive and critical test for BHV tissue mechanical property evaluation [2]. The following study was conducted to determine the feasibility of using this technique to provide fundamental information required for optimizing TEHV scaffold designs.

Dental Pulp Stem Cells for Tissue Engineered Heart Valve

2020 ◽  
Author(s):  
Soontaree Petchdee ◽  
Wilairat Chumsing ◽  
Suruk Udomsom ◽  
Kittiya Thunsiri
Keyword(s):  
Stem Cells ◽  
Mitral Valve ◽  
Heart Valve ◽  
Heart Valves ◽  
Cell Types ◽  
Tensile Tests ◽  
Deciduous Teeth ◽  
Essential Information ◽  
Acquired Heart Disease ◽  
Tissue Engineered Heart Valves

Myxomatous mitral valve degeneration is the most acquired heart disease in dogs. To reduce the clinical progression of mitral valve degeneration and achieve the hemodynamic outcomes, many medical or surgical treatments have been motivated. The objectives of this study is to investigate the suitability of puppy deciduous teeth stem cells as a cell source for tissue engineered heart valves in dog with degenerative valve disease. Puppy deciduous teeth stem cells (pDSCs) were seeded on the scaffolds which made from polylactic acid (PLA), polycaprolactone (PLC) and silicone. The mechanical properties of the tissue engineered heart valves leaflets were characterized by biaxial tensile tests. Results showed that, deciduous teeth stem cells capable of differentiating into a variety of cell types. However, the ability of puppy deciduous teeth stem cells to differentiate declined with increasing passage number which correspond to the number of protein surface marker detection have been shown to decrease substantially by the fifth passage. PLA scaffold is significantly higher tensile strength than other materials. However, silicone showed the highest flaccidity. The results from this study may provide high regenerative capability and the essential information for future directions of heart valve tissue engineering.

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