Non-physiologic Bioreactor Processing Conditions for Heart Valve Tissue Engineering.

Purpose: Conventional methods of seeding decellularized heart valves for heart valve tissue engineering have led to inconsistent results in interstitial cellular repopulation, particularly of the distal valve leaflet, and notably distinct from documented re-endothelialization. The use of bioreactor conditioning mimicking physiologic parameters has been well explored but cellular infiltration remains challenging. Non-characteristic, non-physiologic conditioning parameters within a bioreactor, such as hypoxia and cyclic chamber pressure, may be used to increase the cellular infiltration leading to increased recellularization.

Comparison of Candidate Cell Populations for the Recellularization of Decellularized Heart Valves.

Introduction: Heart valve tissue engineering may provide improved treatment for valvular heart disease, yet development of a tissue engineered heart valve (TEHV) has been limited by incomplete recellularization of the valve leaflets. In this study, we compare the leaflet recellularization potential of candidate cell populations.

Methods: Four cell populations were tested: bone marrow mononuclear cells (MNC), 5 million bone marrow mesenchymal stem cells (MSC), 10 million bone marrow mesenchymal stem cells (MSC2), and 5 million valve interstitial cells (VIC).

Extended bioreactor conditioning of mononuclear cell-seeded heart valve scaffolds.

The tissue-engineered heart valve may be the ideal valve replacement option but still must overcome challenges in leaflet recellularization. This study sought to investigate the potential for leaflet matrix restoration and repopulation following mononuclear cell seeding and extended periods of bioreactor conditioning. Human aortic heart valves were seeded with mononuclear cells and conditioned in a pulsatile bioreactor for 3 days, 3 weeks, or 6 weeks.

Wharton's Jelly Matrix Decellularization for Tissue Engineering Applications.

Scaffolds, both natural and synthetic, used in tissue engineering provide mechanical support to cells. Tissue decellularization has been used to provide natural extracellular matrix scaffolds for tissue engineering purposes. In this chapter we focus on describing the methodology used to decellularize Wharton's jelly matrix, the mucous connective tissue that surrounds umbilical cord vessels, to obtain decellularized Wharton's jelly matrix (DWJM); an extracellular matrix that can be used for tissue engineering purposes.

Decellularized Wharton's Jelly from human umbilical cord as a novel 3D scaffolding material for tissue engineering applications.

In tissue engineering, an ideal scaffold attracts and supports cells thus providing them with the necessary mechanical support and architecture as they reconstruct new tissue in vitro and in vivo. This manuscript details a novel matrix derived from decellularized Wharton's jelly (WJ) obtained from human umbilical cord for use as a scaffold for tissue engineering application. This decellularized Wharton's jelly matrix (DWJM) contained 0.

Species-specific effects of aortic valve decellularization.

Unlabelled: Decellularized heart valves have great potential as a stand-alone valve replacement or as a scaffold for tissue engineering heart valves. Before decellularized valves can be widely used clinically, regulatory standards require pre-clinical testing in an animal model, often sheep. Numerous decellularization protocols have been applied to both human and ovine valves; however, the ways in which a specific process may affect valves of these species differently have not been reported.

Performance of allogeneic bioengineered replacement pulmonary valves in rapidly growing young lambs.

Background: Cardiac allometric organ growth after pediatric valve replacement can lead to patient-prosthesis size mismatch and valve re-replacement, which could be mitigated with allogeneic decellularized pulmonary valves treated with collagen conditioning solutions to enhance biological and mechanical performance, termed "bioengineered valves." In this study, we evaluated functional, dimensional, and biological responses of these bioengineered valves compared with traditional cryopreserved valves implanted in lambs during rapid somatic growth.

Methods: From a consanguineous flock of 13 lambs, the pulmonary valves of 10 lambs (mean weight, 19.

Pulse Duplicator Hydrodynamic Testing of Bioengineered Biological Heart Valves.

There are many heart valve replacements currently available on the market; however, these devices are not ideal for pediatric patients with congenital heart valve defects. Decellularized valve substitutes offer potential for improved clinical outcomes and require pre-clinical testing guidelines and testing systems suitable for non-crosslinked, biological heart valves. The objective of this study was to assess the hydrodynamic performance of intact, bioengineered pulmonary valves using a custom pulse duplicator capable of testing intact biological valved conduits.

Effects of cryopreservation, decellularization and novel extracellular matrix conditioning on the quasi-static and time-dependent properties of the pulmonary valve leaflet.

Decellularized allografts offer potential as heart valve substitutes and scaffolds for cell seeding. The effects of decellularization on the quasi-static and time-dependent mechanical behavior of the pulmonary valve leaflet under biaxial loading conditions have not previously been reported in the literature. In the current study, the stress-strain, relaxation and creep behaviors of the ovine pulmonary valve leaflet were investigated under planar-biaxial loading conditions to determine the effects of decellularization and a novel post-decellularization extracellular matrix (ECM) conditioning process.

Irreversible nanogel formation in surfactant solutions by microporous flow.

Self-assembly of surfactant molecules into micelles of various shapes and forms has been extensively used to synthesize soft nanomaterials. Translucent solutions containing rod-like surfactant micelles can self-organize under flow to form viscoelastic gels. This flow-induced structure (FIS) formation has excited much fundamental research and pragmatic interest as a cost-effective manufacturing route for active nanomaterials.