Recent advances and challenges on application of tissue engineering for treatment of congenital heart disease

Cell-based therapy to boost right ventricular function and cardiovascular performance in hypoplastic left heart syndrome: Current approaches and future directions

Congenital heart disease remains one of the most frequently diagnosed congenital diseases of the newborn, with hypoplastic left heart syndrome (HLHS) being considered one of the most severe. This univentricular defect was uniformly fatal until the introduction, 40 years ago, of a complex surgical palliation consisting of multiple staged procedures spanning the first 4 years of the child's life. While survival has improved substantially, particularly in experienced centers, ventricular failure requiring heart transplant and a number of associated morbidities remain ongoing clinical challenges for these patients. Cell-based therapies aimed at boosting ventricular performance are under clinical evaluation as a novel intervention to decrease morbidity associated with surgical palliation. In this review, we will examine the current burden of HLHS and current modalities for treatment, discuss various cells therapies as an intervention while delineating challenges and future directions for this therapy for HLHS and other congenital heart diseases.

Promotion of right ventricular outflow tract reconstruction using a novel cardiac patch incorporated with hypoxia-pretreated urine-derived stem cells

Approximately 25% of patients with congenital heart disease require implantation of patches to repair. However, most of the currently available patches are made of inert materials with unmatched electrical conductivity and mechanical properties, which may lead to an increased risk for arrhythmia and heart failure. In this study, we have developed a novel Polyurethane/Small intestinal submucosa patch (PSP) with mechanical and electrical properties similar to those of the native myocardial tissue, and assessed its feasibility for the reconstruction of right ventricular outflow tract. A right ventricular outflow tract reconstruction model was constructed in 40 rabbits. Compared with commercially available bovine pericardium patch, the PSP patch has shown better histocompatibility and biodegradability, in addition with significantly improved cardiac function. To tackle the significant fibrosis and relatively poor vascularization during tissue remodeling, we have further developed a bioactive patch by incorporating the PSP composites with urine-derived stem cells (USCs) which were pretreated with hypoxia. The results showed that the hypoxia-pretreated bioactive patch could significantly inhibit fibrosis and promote vascularization and muscularization, resulting in better right heart function. Our findings suggested that the PSP patch combined with hypoxia-pretreated USCs may provide a better strategy for the treatment of congenital heart disease.

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A novel cardiac patch (PSP) with mechanical and electrical properties similar to native myocardium.

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PSP patch improved cardiac function in right ventricular outflow tract reconstruction model.

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Hypoxia pretreated USCs combined PSP patch promoted vascularization and inhibited fibrosis.

Prospect of 3D bioprinting over cardiac cell therapy and conventional tissue engineering in the treatment of COVID-19 patients with myocardial injury

Due to multiple mutations of SARS-CoV-2, the mystery of defeating the virus is still unknown. Cardiovascular complications are one of the most concerning effects of COVID-19 recently, originating from direct and indirect mechanisms. These complications are associated with long-term Cardio-vascular diseases and can induce sudden cardiac death in both infected and recovered COVID-19 patients. The purpose of this research is to do a competitive analysis between conventional techniques with the upgraded alternative 3D bioprinting to replace the damaged portion of the myocardium. Additionally, this study focuses on the potential of 3D bioprinting to be a novel alternative. Finally, current challenges and future perspective of 3D bioprinting technique is briefly discussed.

Umbilical Cord Pericytes Provide a Viable Alternative to Mesenchymal Stem Cells for Neonatal Vascular Engineering

Reconstructive surgery of congenital heart disease (CHD) remains inadequate due to the inability of prosthetic grafts to match the somatic growth of pediatric patients. Functionalization of grafts with mesenchymal stem cells (MSCs) may provide a solution. However, MSCs represent a heterogeneous population characterized by wide diversity across different tissue sources. Here we investigated the suitability of umbilical cord pericytes (UCPs) in neonatal vascular engineering. Explant outgrowth followed by immunomagnetic sorting was used to isolate neural/glial antigen 2 (NG2)+/CD31- UCPs. Expanded NG2 UCPs showed consistent antigenic phenotype, including expression of mesenchymal and stemness markers, and high proliferation rate. They could be induced to a vascular smooth muscle cell-like phenotype after exposure to differentiation medium, as evidenced by the expression of transgelin and smooth muscle myosin heavy chain. Analysis of cell monolayers and conditioned medium revealed production of extracellular matrix proteins and the secretion of major angiocrine factors, which conferred UCPs with ability to promote endothelial cell migration and tube formation. Decellularized swine-derived grafts were functionalized using UCPs and cultured under static and dynamic flow conditions. UCPs were observed to integrate into the outer layer of the graft and modify the extracellular environment, resulting in improved elasticity and rupture strain in comparison with acellular grafts. These findings demonstrate that a homogeneous pericyte-like population can be efficiently isolated and expanded from human cords and integrated in acellular grafts currently used for repair of CHD. Functional assays suggest that NG2 UCPs may represent a viable option for neonatal tissue engineering applications.

Recent advancements in cardiovascular bioprinting and bioprinted cardiac constructs

Three-dimensionally bioprinted cardiac constructs with biomimetic bioink helps to create native-equivalent cardiac tissues to treat patients with myocardial infarction.

Human cardiac extracellular matrix-chitosan-gelatin composite scaffold and its endothelialization

The present study developed a cardiac extracellular matrix-chitosan-gelatin (cECM-CG) composite scaffold that can be used as a tissue-engineered heart patch and investigated its endothelialization potential by incorporating CD34⁺ endothelial progenitor cells (EPCs). The cECM-CG composite scaffold was prepared by blending cardiac extracellular matrix (cECM) with biodegradable chitosan-gelatin (CG). The mixture was lyophilized using vacuum freeze-drying. CD34⁺ EPCs were isolated and seeded on the scaffolds, and then the endothelialization effect was subsequently investigated. Effects of the scaffolds on CD34⁺ EPCs survival and proliferation were evaluated by immunofluorescence staining and MTT assay. Cell differentiation into endothelial cells and the influence of the scaffolds on cell differentiation were investigated by reverse transcription-quantitative PCR (RT-qPCR), immunofluorescence staining and tube formation assay. The present results indicated that most cells were removed after decellularization, but the main extracellular matrix components were retained. Scanning electron microscopy imaging illustrated three-dimensional and porous scaffolds. The present results suggested the cECM-CG composite scaffold had a higher water absorption ability compared with the CG scaffold. Additionally, compared with the CG scaffold, the cECM-CG composite scaffold significantly increased cell survival and proliferation, which suggested its non-toxicity and biocompatibility. Furthermore, RT-qPCR, immunofluorescence and tube formation assay results indicated that CD34⁺ EPCs differentiated into endothelial cells, and the cECM-CG composite scaffold promoted this differentiation process. In conclusion, the present results indicated that the human cECM-CG composite scaffold generated in the present study was a highly porous, biodegradable three-dimensional scaffold which supported endothelialization of seeded CD34⁺ EPCs. The present results suggested that this cECM-CG composite scaffold may be a promising heart patch for use in heart tissue engineering for congenital heart disease.