Long term efficacy and fate of a right ventricular outflow tract replacement using an elastomeric cardiac patch consisting of caprolactone and D,L-lactide copolymers.

For decades, researchers have investigated the ideal material for clinical use in the cardiovascular field. Several substitute materials are used clinically, but each has drawbacks. Recently we developed biodegradable and elastic poly(ε-caprolactone-co-D,L-lactide) (P(CL-DLLA)) copolymers by adjusting the CL/DLLA composition, and evaluated the long-term efficacy and outcomes of these copolymers when used for right ventricular outflow tract (RVOT) replacement.

Entire Circumferential Reconstruction of the Right Atrium Surrounded by Angiosarcoma.

Primary cardiac angiosarcomas are frequently found at a large size with infiltration into the adjacent heart structure owing to their asymptomatic characteristics until an advanced stage. Therefore, extensive resection is often required to achieve a good prognosis. We herein report a case of entire circumferential resection of the right atrium surrounded by angiosarcoma and excellent three-dimensional reconstruction of the right atrium.

Early and Late Outcomes of Thoracic Aortic Surgery in Hemodialysis Patients.

Background: The number of cardiovascular surgeries among hemodialysis patients is increasing according to the growing population of hemodialysis patients; however, the clinical outcome has not yet been clarified, especially in thoracic aortic surgery. The purpose of this study was to assess the early and late outcomes of thoracic aortic surgery in hemodialysis patients.

Methods: We retrospectively analyzed the outcomes of 700 consecutive open thoracic aortic surgeries from 2002 to 2014.

Impact of Surgical Stroke on the Early and Late Outcomes After Thoracic Aortic Operations.

Background: Thoracic aortic operations still remain associated with substantial risks of death and neurologic injury. This study investigated the impact of surgical stroke on the early and late outcomes, focusing on the physical status and quality of life (QOL).

Methods: From 1986 to 2008, 500 patients (aged 63 ± 13 years) underwent open thoracic aortic repair for root and ascending (31%), arch (39%), extended arch (10%), and descending and thoracoabdominal (19%) aneurysms.

Therapeutic potential of bone marrow-derived mesenchymal stem cells in formed aortic aneurysms of a mouse model.

Objectives: An aortic aneurysm (AA) is caused by atherosclerosis with chronic inflammation. Mesenchymal stem cells (MSCs) have potential anti-inflammatory properties. In this study, we examined whether an already-formed AA can be treated by intravenous injection of bone marrow-derived (BM)-MSCs in a mouse model.

The effect of polymer degradation time on functional outcomes of temporary elastic patch support in ischemic cardiomyopathy.

Biodegradable polyurethane patches have been applied as temporary mechanical supports to positively alter the remodeling and functional loss following myocardial infarction. How long such materials need to remain in place is unclear. Our objective was to compare the efficacy of porous onlay support patches made from one of three types of biodegradable polyurethane with relatively fast (poly(ester urethane)urea; PEUU), moderate (poly(ester carbonate urethane)urea; PECUU), and slow (poly(carbonate urethane)urea; PCUU) degradation rates in a rat model of ischemic cardiomyopathy.

Biodegradable elastic patch plasty ameliorates left ventricular adverse remodeling after ischemia-reperfusion injury: a preclinical study of a porous polyurethane material in a porcine model.

Objective: Myocardial infarction (MI) can lead to irreversible adverse left ventricular remodeling resulting in subsequent severe dysfunction. The objective of this study was to investigate the potential for biodegradable, elastomeric patch implantation to positively alter the remodeling process after MI in a porcine model.

Methods: Yorkshire pigs underwent a 60-minute catheter balloon occlusion of the left circumflex artery.

Placement of an elastic biodegradable cardiac patch on a subacute infarcted heart leads to cellularization with early developmental cardiomyocyte characteristics.

Background: Placement of an elastic biodegradable patch onto a subacute myocardial infarct (MI) provides temporary elastic support that may act to effectively alter adverse left ventricular (LV) remodeling processes.

Methods: Two weeks after permanent left coronary ligation in Lewis rats, the infarcted anterior wall was covered with polyester urethane urea (MI + PEUU; n = 15) or expanded polytetrafluoroethylene (MI + ePTFE; n = 15) patches, or had no implantation (MI + sham; n = 12). Eight weeks after surgery, cardiac function and histology were assessed.

Right ventricular outflow tract repair with a cardiac biologic scaffold.

Background: Surgical reconstruction of congenital heart defects is often limited by the nonresorbable material used to approximate normal anatomy. In contrast, biologic scaffold materials composed of resorbable non-cross-linked extracellular matrix (ECM) have been used for tissue reconstruction of multiple organs and are replaced by host tissue. Preparation of whole organ ECM by decellularization through vascular perfusion can maintain much of the native three-dimensional (3D) structure, strength, and tissue-specific composition.

Application of the HeartLander crawling robot for injection of a thermally sensitive anti-remodeling agent for myocardial infarction therapy.

The injection of a mechanical bulking agent into the left ventricular (LV) wall of the heart has shown promise as a therapy for maladaptive remodeling of the myocardium after myocardial infarct (MI). The HeartLander robotic crawler presented itself as an ideal vehicle for minimally-invasive, highly accurate epicardial injection of such an agent. Use of the optimal bulking agent, a thermosetting hydrogel developed by our group, presents a number of engineering obstacles, including cooling of the miniaturized injection system while the robot is navigating in the warm environment of a living patient.

Engineered fetal cardiac graft preserves its cardiomyocyte proliferation within postinfarcted myocardium and sustains cardiac function.

The goal of cellular cardiomyoplasty is to replace damaged myocardium by healthy myocardium achieved by host myocardial regeneration and/or transplantation of donor cardiomyocytes (CMs). In the case of CM transplantation, studies suggest that immature CMs may be the optimal cell type to survive and functionally integrate into damaged myocardium. In the present study, we tested the hypothesis that active proliferation of immature CMs contributes graft survival and functional recovery of recipient myocardium.

Intra-myocardial biomaterial injection therapy in the treatment of heart failure: Materials, outcomes and challenges.

Heart failure initiated by coronary artery disease and myocardial infarction (MI) is a widespread, debilitating condition for which there are a limited number of options to prevent disease progression. Intra-myocardial biomaterial injection following MI theoretically provides a means to reduce the stresses experienced by the infarcted ventricular wall, which may alter the pathological remodeling process in a positive manner. Furthermore, biomaterial injection provides an opportunity to concurrently introduce cellular components and depots of bioactive agents.

Tailoring the degradation kinetics of poly(ester carbonate urethane)urea thermoplastic elastomers for tissue engineering scaffolds.

Biodegradable elastomeric scaffolds are of increasing interest for applications in soft tissue repair and regeneration, particularly in mechanically active settings. The rate at which such a scaffold should degrade for optimal outcomes, however, is not generally known and the ability to select from similar scaffolds that vary in degradation behavior to allow such optimization is limited. Our objective was to synthesize a family of biodegradable polyurethane elastomers where partial substitution of polyester segments with polycarbonate segments in the polymer backbone would lead to slower degradation behavior.

Morphological and mechanical characteristics of the reconstructed rat abdominal wall following use of a wet electrospun biodegradable polyurethane elastomer scaffold.

Although a variety of materials are currently used for abdominal wall repair, general complications encountered include herniation, infection, and mechanical mismatch with native tissue. An approach wherein a degradable synthetic material is ultimately replaced by tissue mechanically approximating the native state could obviate these complications. We report here on the generation of biodegradable scaffolds for abdominal wall replacement using a wet electrospinning technique in which fibers of a biodegradable elastomer, poly(ester urethane)urea (PEUU), were concurrently deposited with electrosprayed serum-based culture medium.

Naive rat amnion-derived cell transplantation improved left ventricular function and reduced myocardial scar of postinfarcted heart.

Stem cells contained in the amniotic membrane may be useful for cellular repair of the damaged heart. Previously, we showed that amnion-derived cells (ADCs) express embryonic stem cell surface markers and pluripotent stem cell-specific transcription factor genes. These ADCs also possess the potential for mesoderm (cardiac) lineage differentiation.

A three-dimensional gel bioreactor for assessment of cardiomyocyte induction in skeletal muscle-derived stem cells.

Skeletal muscle-derived stem cells (MDSCs) are able to differentiate into cardiomyocytes (CMs). However, it remains to be investigated whether differentiated CMs contract similar to native CMs. Here, we developed a three-dimensional collagen gel bioreactor (3DGB) that induces a working CM phenotype from MDSCs, and the contractile properties are directly measured as an engineered cardiac tissue.

Synthesis, characterization and therapeutic efficacy of a biodegradable, thermoresponsive hydrogel designed for application in chronic infarcted myocardium.

Injection of a bulking material into the ventricular wall has been proposed as a therapy to prevent progressive adverse remodeling due to high wall stresses that develop after myocardial infarction. Our objective was to design, synthesize and characterize a biodegradable, thermoresponsive hydrogel for this application based on copolymerization of N-isopropylacrylamide (NIPAAm), acrylic acid (AAc) and hydroxyethyl methacrylate-poly(trimethylene carbonate) (HEMAPTMC). By evaluating a range of monomer ratios, poly(NIPAAm-co-AAc-co-HEMAPTMC) at a feed ratio of 86/4/10 was shown to be ideal since it formed a hydrogel at 37 degrees C, and gradually became soluble over a 5 month period in vitro through hydrolytic cleavage of the PTMC residues.

Elastase-sensitive elastomeric scaffolds with variable anisotropy for soft tissue engineering.

Purpose: To develop elastase-sensitive polyurethane scaffolds that would be applicable to the engineering of mechanically active soft tissues.

Methods: A polyurethane containing an elastase-sensitive peptide sequence was processed into scaffolds by thermally induced phase separation. Processing conditions were manipulated to alter scaffold properties and anisotropy.

Computer-assisted navigation applied to fetal cardiac intervention.

Background: Prenatal cardiac interventions (PCI) for human fetal aortic valve (AoV) stenosis can reduce left ventricular hypoplasia and restore ventricular growth and function. However, 'freehand' needle delivery from the maternal skin through the uterine wall, fetal chest and ventricular apex to cross the fetal AoV remains technically challenging and time intensive, and is the rate-limiting step in the procedure.

Methods: We developed a computer-assisted navigation (CANav) system that tracks the position and orientation of a two-dimensional (2D) ultrasound image relative to the trajectory of an electromagnetic (EM) embedded needle and stylet.

An elastic, biodegradable cardiac patch induces contractile smooth muscle and improves cardiac remodeling and function in subacute myocardial infarction.

Objectives: Our objective in this study was to apply an elastic, biodegradable polyester urethane urea (PEUU) cardiac patch onto subacute infarcts and to examine the resulting cardiac ventricular remodeling and performance.

Background: Myocardial infarction induces loss of contractile mass and scar formation resulting in adverse left ventricular (LV) remodeling and subsequent severe dysfunction.

Methods: Lewis rats underwent proximal left coronary ligation.

In vivo evaluation of a porous, elastic, biodegradable patch for reconstructive cardiac procedures.

Purpose: Several synthetic materials have been used for cardiac reconstruction in patients with complex congenital heart defects. These materials are not viable, do not grow with children, and may necessitate reoperation. We report here on the cardiac implantation of a recently developed, degradable porous material designed to facilitate cellular ingrowth during the healing process.

Preparation and characterization of highly porous, biodegradable polyurethane scaffolds for soft tissue applications.

In the engineering of soft tissues, scaffolds with high elastance and strength coupled with controllable biodegradable properties are necessary. To fulfill such design criteria we have previously synthesized two kinds of biodegradable polyurethaneureas, namely poly(ester urethane)urea (PEUU) and poly(ether ester urethane)urea (PEEUU) from polycaprolactone, polycaprolactone-b-polyethylene glycol-b-polycaprolactone, 1,4-diisocyanatobutane and putrescine. PEUU and PEEUU were further fabricated into scaffolds by thermally induced phase separation using dimethyl sulfoxide (DMSO) as a solvent.