Read by QxMD icon Read

Mechanical heart valve engineering

M Hirschvogel, M Bassilious, L Jagschies, S M Wildhirt, M W Gee
A model for patient-specific cardiac mechanics simulation is introduced, incorporating a 3-dimensional finite element model of the ventricular part of the heart which is coupled to a reduced-order 0-dimensional closed-loop vascular system, heart valve and atrial chamber model.The ventricles are modeled by a nonlinear orthotropic passive material law. The electrical activation is mimicked by a prescribed parametrized active stress acting along a generic muscle fiber orientation. Our activation function is constructed such that the start of ventricular contraction and relaxation as well as the active stress curve's slope are parameterized...
October 15, 2016: International Journal for Numerical Methods in Biomedical Engineering
Heather N Hutson, Taylor Marohl, Matthew Anderson, Kevin Eliceiri, Paul Campagnola, Kristyn S Masters
Disorganization of the valve extracellular matrix (ECM) is a hallmark of calcific aortic valve disease (CAVD). However, while microarchitectural features of the ECM can strongly influence the biological and mechanical behavior of tissues, little is known about the ECM microarchitecture in CAVD. In this work, we apply advanced imaging techniques to quantify spatially heterogeneous changes in collagen microarchitecture in CAVD. Human aortic valves were obtained from individuals between 50 and 75 years old with no evidence of valvular disease (healthy) and individuals who underwent valve replacement surgery due to severe stenosis (diseased)...
2016: PloS One
Luis G Hurtado-Aguilar, Shane Mulderrig, Ricardo Moreira, Nima Hatam, Jan Spillner, Thomas Schmitz-Rode, Stefan Jockenhoevel, Petra Mela
Tissue-engineered heart valves are developed in bioreactors where biochemical and mechanical stimuli are provided for extracellular matrix formation. During this phase, the monitoring possibilities are limited by the need to maintain the sterility and the integrity of the valve. Therefore, noninvasive and nondestructive techniques are required. As such, optical imaging is commonly used to verify valve's functionality in vitro. It provides important information (i.e. leaflet symmetry, geometric orifice area, closing and opening times) which is, however, usually limited to a singular view along the central axis from the outflow side...
September 27, 2016: Tissue Engineering. Part C, Methods
Ishita Tandon, Atefeh Razavi, Prashanth Ravishankar, Addison Walker, Nasya M Sturdivant, Ngoc Thien Lam, Jeffrey C Wolchok, Kartik Balachandran
Valve interstitial cells are dispersed throughout the heart valve and play an important role in maintaining its integrity, function, and phenotype. While prior studies have detailed the role of external mechanical and biological factors in the function of the interstitial cell, the role of cell shape in regulating contractile function, in the context of normal and diseased phenotypes, is not well understood. Thus, the aim of this study was to elucidate the link between cell shape, phenotype, and acute functional contractile output...
October 3, 2016: Journal of Biomechanics
Costantino Del Gaudio, Pier Luca Gasbarroni, Giovanni Paolo Romano
End-stage failing heart valves are currently replaced by mechanical or biological prostheses. Both types positively contribute to restore the physiological function of native valves, but a number of drawbacks limits the expected performances. In order to improve the outcome, tissue engineering can offer an alternative approach to design and fabricate innovative heart valves capable to support the requested function and to promote the formation of a novel, viable and correctly operating physiological structure...
December 2016: Journal of the Mechanical Behavior of Biomedical Materials
Maurizio Pesce, Rosaria Santoro
Although traditionally linked to the physiology of tissues in 'motion', the ability of the cells to transduce external forces into coordinated gene expression programs is emerging as an integral component of the fundamental structural organization of multicellular organisms with consequences for cell differentiation even from the beginning of embryonic development. The ability of the cells to 'feel' the surrounding mechanical environment, even in the absence of tissue motion, is then translated into 'positional' or 'social' sensing that instructs, before the organ renewal, the correct patterning of the embryos...
August 7, 2016: Pharmacology & Therapeutics
Frederick J Schoen
The clinical and pathological features of the most frequent intrinsic structural diseases that affect the heart valves are well established, but heart valve disease mechanisms are poorly understood, and effective treatment options are evolving. Major advances in the understanding of the structure, function and biology of native valves and the pathobiology, biomaterials and biomedical engineering, and the clinical management of valvular heart disease have occurred over the past several decades. This communication reviews contemporary considerations relative to the pathology of valvular heart disease, including (1) clinical significance and epidemiology of valvular heart disease; (2) functional and dynamic valvular macro-, micro- and ultrastructure; (3) causes, morphology and mechanisms of human valvular heart disease; and (4) pathologic considerations in valve replacement, repair and, potentially, regeneration of the heart valves...
August 8, 2016: Cardiovascular Engineering and Technology
Israel Gonzalez de Torre, Miriam Weber, Luis Quintanilla, Matilde Alonso, Stefan Jockenhoevel, José Carlos Rodríguez Cabello, Petra Mela
In the field of tissue engineering, the properties of the scaffolds are of crucial importance for the success of the application. Hybrid materials combine the properties of the different components that constitute them. In this study hybrid gels of Elastin-Like Recombinamer (ELR) and fibrin were prepared with a range of polymer concentrations and ELR-to-fibrin ratios. The correlation between SEM micrographs, porosities, swelling ratios and rheological properties was discussed and a poroelastic mechanism was suggested to explain the mechanical behavior of the hybrid gels...
August 16, 2016: Biomaterials Science
Ricardo Moreira, Christine Neusser, Magnus Kruse, Shane Mulderrig, Frederic Wolf, Jan Spillner, Thomas Schmitz-Rode, Stefan Jockenhoevel, Petra Mela
The mechanical properties of tissue-engineered heart valves still need to be improved to enable their implantation in the systemic circulation. The aim of this study is to develop a tissue-engineered valve for the aortic position - the BioTexValve - by exploiting a bio-inspired composite textile scaffold to confer native-like mechanical strength and anisotropy to the leaflets. This is achieved by multifilament fibers arranged similarly to the collagen bundles in the native aortic leaflet, fixed by a thin electrospun layer directly deposited on the pattern...
August 2016: Advanced Healthcare Materials
Hanif Ullah, Fazli Wahid, Hélder A Santos, Taous Khan
Bacterial cellulose (BC) synthesized by certain species of bacteria, is a fascinating biopolymer with unique physical and mechanical properties. BC's applications range from traditional dessert, gelling, stabilizing and thickening agent in the food industry to advanced high-tech applications, such as immobilization of enzymes, bacteria and fungi, tissue engineering, heart valve prosthesis, artificial blood vessels, bone, cartilage, cornea and skin, and dental root treatment. Various BC-composites have been designed and investigated in order to enhance its biological applicability...
October 5, 2016: Carbohydrate Polymers
Shaohua Wu, Bin Duan, Penghong Liu, Caidan Zhang, Xiaohong Qin, Jonathan T Butcher
Nanofibrous scaffolds with defined architectures and anisotropic mechanical properties are attractive for many tissue engineering and regenerative medicine applications. Here, a novel electrospinning system is developed and implemented to fabricate continuous processable uniaxially aligned nanofiber yarns (UANY). UANY were processed into fibrous tissue scaffolds with defined anisotropic material properties using various textile-forming technologies, i.e., braiding, weaving, and knitting techniques. UANY braiding dramatically increased overall stiffness and strength compared to the same number of UANY unbraided...
July 6, 2016: ACS Applied Materials & Interfaces
Cenk Sarı, Abdullah Nabi Aslan, Serdal Baştuğ, Murat Akçay, Nihal Akar Bayram, Emine Bilen, Hüseyin Ayhan, Hacı Ahmet Kasapkara, Tahir Durmaz, Telat Keleş, Engin Bozkurt
BACKGROUND: Chronic increased afterload due to severe aortic stenosis (AS) results in com-pensatory concentric left ventricular (LV) hypertrophy and LV dysfunction. These in turn cause remodeling of the left heart. The aim of this study was to investigate the acute effect of transcatheter aortic valve implantation (TAVI) on left atrial (LA) mechanics and LV diastolic function. METHODS: The study consisted of a total of 35 consecutive patients (mean age was 77.7 ± 5...
2016: Cardiology Journal
Frederick J Schoen, Avrum I Gotlieb
The past several decades have witnessed major advances in the understanding of the structure, function, and biology of native valves and the pathobiology and clinical management of valvular heart disease. These improvements have enabled earlier and more precise diagnosis, assessment of the proper timing of surgical and interventional procedures, improved prosthetic and biologic valve replacements and repairs, recognition of postoperative complications and their management, and the introduction of minimally invasive approaches that have enabled definitive and durable treatment for patients who were previously considered inoperable...
July 2016: Cardiovascular Pathology: the Official Journal of the Society for Cardiovascular Pathology
Andrew K Capulli, Luke A MacQueen, Blakely B O'Connor, Stephanie Dauth, Kevin Kit Parker
Medications based on ergoline-derived dopamine and serotonin agonists are associated with off-target toxicities that include valvular heart disease (VHD). Reports of drug-induced VHD resulted in the withdrawal of appetite suppressants containing fenfluramine and phentermine from the US market in 1997 and pergolide, a Parkinson's disease medication, in 2007. Recent evidence suggests that serotonin receptor activity affected by these medications modulates cardiac valve interstitial cell activation and subsequent valvular remodeling, which can lead to cardiac valve fibrosis and dysfunction similar to that seen in carcinoid heart disease...
July 2016: Cardiovascular Pathology: the Official Journal of the Society for Cardiovascular Pathology
Alicia A Blancas, Liezl R Balaoing, Francisca M Acosta, K Jane Grande-Allen
Heart valvular endothelial cells (VECs) are distinct from vascular endothelial cells (ECs), but have an uncertain context within the spectrum of known endothelial phenotypes, including lymphatic ECs (LECs). Profiling the phenotypes of the heart valve surface VECs would facilitate identification of a proper seeding population for tissue-engineered valves, as well as elucidate mechanisms of valvular disease. Porcine VECs and porcine aortic ECs (AECs) were isolated from pig hearts and characterized to assess known EC and LEC markers...
2016: Cells, Tissues, Organs
Daniel S Puperi, Ronan W O'Connell, Zoe E Punske, Yan Wu, Jennifer L West, K Jane Grande-Allen
Advanced tissue engineered heart valves must be constructed from multiple materials to better mimic the heterogeneity found in the native valve. The trilayered structure of aortic valves provides the ability to open and close consistently over a full human lifetime, with each layer performing specific mechanical functions. The middle spongiosa layer consists primarily of proteoglycans and glycosaminoglycans, providing lubrication and dampening functions as the valve leaflet flexes open and closed. In this study, hyaluronan hydrogels were tuned to perform the mechanical functions of the spongiosa layer, provide a biomimetic scaffold in which valve cells were encapsulated in 3D for tissue engineering applications, and gain insight into how valve cells maintain hyaluronan homeostasis within heart valves...
May 9, 2016: Biomacromolecules
Bin Duan
3D bioprinting is a group of rapidly growing techniques that allows building engineered tissue constructs with complex and hierarchical structures, mechanical and biological heterogeneity. It enables implementation of various bioinks through different printing mechanisms and precise deposition of cell and/or biomolecule laden biomaterials in predefined locations. This review briefly summarizes applicable bioink materials and various bioprinting techniques, and presents the recent advances in bioprinting of cardiovascular tissues, with focusing on vascularized constructs, myocardium and heart valve conduits...
April 11, 2016: Annals of Biomedical Engineering
Ying Lei, Zannatul Ferdous
With the increase in average life expectancy and growing aging population, lack of functional grafts for replacement surgeries has become a severe problem. Engineered tissues are a promising alternative to this problem because they can mimic the physiological function of the native tissues and be cultured on demand. Cyclic stretch is important for developing many engineered tissues such as hearts, heart valves, muscles, and bones. Thus a variety of stretch bioreactors and corresponding scaffolds have been designed and tested to study the underlying mechanism of tissue formation and to optimize the mechanical conditions applied to the engineered tissues...
May 2016: Biotechnology Progress
Daphne van Geemen, Ana L F Soares, Pim J A Oomen, Anita Driessen-Mol, Marloes W J T Janssen-van den Broek, Antoon J van den Bogaerdt, Ad J J C Bogers, Marie-José T H Goumans, Frank P T Baaijens, Carlijn V C Bouten
There is limited information about age-specific structural and functional properties of human heart valves, while this information is key to the development and evaluation of living valve replacements for pediatric and adolescent patients. Here, we present an extended data set of structure-function properties of cryopreserved human pulmonary and aortic heart valves, providing age-specific information for living valve replacements. Tissue composition, morphology, mechanical properties, and maturation of leaflets from 16 pairs of structurally unaffected aortic and pulmonary valves of human donors (fetal-53 years) were analyzed...
2016: PloS One
Marco Bartosch, Heiner Peters, Hendrik Spriestersbach, Darach O H-Ici, Felix Berger, Boris Schmitt
Transcatheter heart valve implantation is an emerging technology and an alternative to surgical valve replacement. Most existing systems consist of valves sewn into balloon-expandable stents with a delivery catheter functioning with the specific valve only. The aim of this study was to develop a universally applicable delivery system (DS) for plane stents, valves sewn into both balloon-expandable and self-expandable stents and feasible for use with different access routes. A DS was designed and manufactured in five different diameters...
September 2016: Annals of Biomedical Engineering
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"