Search

Congenital heart disease (CHD) is the most common birth defect, requiring invasive surgery often before a child's first birthday. Current materials used during CHD surgery lack the ability to grow, remodel, and regenerate. To solve those limitations, 3D bioprinting is an emerging tool with the capability to create tailored constructs based on patients' own imaging data with the ability to grow and remodel once implanted in children with CHD. It has the potential to integrate multiple bioinks with several cell types and biomolecules within 3D-bioprinted constructs that exhibit good structural fidelity, stability, and mechanical integrity. This review gives an overview of CHD and recent advancements in 3D bioprinting technologies with potential use in the treatment of CHD. Moreover, the selection of appropriate biomaterials based on their chemical, physical, and biological properties that are further manipulated to suit their application are also discussed. An introduction to bioink formulations composed of various biomaterials with emphasis on multiple cell types and biomolecules is briefly overviewed. Vasculogenesis and angiogenesis of prefabricated 3D-bioprinted structures and novel 4D printing technology are also summarized. Finally, we discuss several restrictions and our perspective on future directions in 3D bioprinting technologies in the treatment of CHD.

Objectives: Intermittent cold blood cardioplegia is commonly used in children, whereas intermittent warm blood cardioplegia is widely used in adults. We aimed to compare clinical and biochemical outcomes with these 2 methods., Methods: A single-centre, randomized controlled trial was conducted to compare the effectiveness of warm (≥34°C) versus cold (4-6°C) antegrade cardioplegia in children. The primary outcome was cardiac troponin T over the 1st 48 postoperative hours. Intensive care teams were blinded to group allocation. Outcomes were compared by intention-to-treat using linear mixed-effects, logistic or Cox regression., Results: 97 participants with median age of 1.2 years were randomized (49 to warm, 48 to cold cardioplegia); 59 participants (61%) had a risk-adjusted congenital heart surgery score of 3 or above. There were no deaths and 92 participants were followed to 3-months. Troponin release was similar in both groups [geometric mean ratio 1.07; 95% confidence interval (CI) 0.79-1.44; P = 0.66], as were other cardiac function measures (echocardiography, arterial and venous blood gases, vasoactive-inotrope score, arrhythmias). Intensive care stay was on average 14.6 h longer in the warm group (hazard ratio 0.52; 95% CI 0.34-0.79; P = 0.003), with a trend towards longer overall hospital stays (hazard ratio 0.66; 95% CI 0.43-1.02; P = 0.060) compared with the cold group. This could be related to more unplanned reoperations on bypass in the warm group compared to cold group (3 vs 1)., Conclusions: Warm blood cardioplegia is a safe and reproducible technique but does not provide superior myocardial protection in paediatric heart surgery., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

The materials available for the right ventricular outflow tract (RVOT) reconstruction in patients with tetralogy of fallot (TOF)/pulmonary atresia come with the severe limitation of long-term degeneration and lack of growth potential, causing right ventricular dysfunction, aneurysm formation, and arrhythmias, thus necessitating several high-risk reoperations throughout patients' lives. In this study, we evaluated the capacity of mesenchymal stem cells (MSCs) derived from the Wharton's Jelly (WJ-MSCs), the gelatinous inner portion of the umbilical cord, to grow and recellularize an extracellular matrix (ECM) graft in our optimized xeno-free, good manufacturing practice-compliant culture system. WJ-MSCs were phenotypically and functionally characterized by flow cytometry and multilineage differentiation capacity, respectively. The typical MSC immunophenotype and functional characteristics were retained in our xeno-free culture system, as well as the capacity to grow and engraft onto a naturally occurring scaffold. WJ-MSCs, from both human and swine source, showed excellent capacity to recellularize ECM graft producing a living cell-seeded construct. In addition, we have provided an in vivo proof of concept of feasibility of the cellularized conduit, engineered with swine WJ-MSCs, to be used in a novel porcine model of main pulmonary artery reconstruction, where it showed good integration within the host tissue. Our study indicates that the addition of WJ-MSCs to the ECM scaffold can upgrade the material, converting it into a living tissue, with the potential to grow, repair, and remodel the RVOT. These results could potentially represent a paradigm shift in pediatric cardiac intervention toward new modalities for effective and personalized surgical restoration of pulmonary artery and RVOT function in TOF/pulmonary atresia patients. Impact Statement The materials available for pulmonary artery reconstruction in pediatric patients with Congenital Heart Defect come with the limitation of long-term degeneration and lack of growth, thus necessitating several reoperations. Here, we describe a novel approach combining perinatal stem cells and naturally occurring scaffold to create a living tissue engineered conduit that showed good growth potential in a pulmonary artery reconstruction porcine model. We envision this approach is of great interest and relevance in tissue engineering field applied to cardiovascular regenerative medicine, as it may open up new avenues for correction of congenital cardiac defects, with remarkable medical and social benefits.

Lack of growth potential of available grafts represents a bottleneck in the correction of congenital heart defects. Here we used a swine small intestinal submucosa (SIS) graft functionalized with mesenchymal stem cell (MSC)-derived vascular smooth muscle cells (VSMCs), for replacement of the pulmonary artery in piglets. MSCs were expanded from human umbilical cord blood or new-born swine peripheral blood, seeded onto decellularized SIS grafts and conditioned in a bioreactor to differentiate into VSMCs. Results indicate the equivalence of generating grafts engineered with human or swine MSC-derived VSMCs. Next, we conducted a randomized, controlled study in piglets (12-15 kg), which had the left pulmonary artery reconstructed with swine VSMC-engineered or acellular conduit grafts. Piglets recovered well from surgery, with no casualty and similar growth rate in either group. After 6 months, grafted arteries had larger circumference in the cellular group (28.3 ± 2.3 vs 18.3 ± 2.1 mm, P < 0.001), but without evidence of aneurism formation. Immunohistochemistry showed engineered grafts were composed of homogeneous endothelium covered by multi-layered muscular media, whereas the acellular grafts exhibited a patchy endothelial cell layer and a thinner muscular layer. RESULTS: show the feasibility and efficacy of pulmonary artery reconstruction using clinically available grafts engineered with allogeneic VSMCs in growing swine., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Mesenchymal stem cells (MSCs) are attractive tools for regenerative medicine because of their multidifferentiation potential and immunomodulation capacity. In congenital heart defect surgical correction, replacement grafts lacking growth potential are commonly used. Tissue engineering promises to overcome the limitations of these grafts. In this study, we hypothesized that human thymus-derived MSCs are a suitable tool to tissue engineer a living vascular graft with good integration and patency once implanted in vivo. Human thymus-derived MSCs (hT-MSCs) were identified by the expression of MSC markers and mesenchymal differentiation potential. When cultured onto natural scaffold to produce tissue-engineered graft, hT-MSCs exhibited great proliferation potential and the ability to secrete their own extracellular matrix. In addition, when implanted in vivo in a piglet model of left pulmonary grafting, the engineered graft exhibited good integration within the host tissue, indicating potential suitability for corrective cardiovascular surgery. The optimized xeno-free, good manufacturing practices-compliant culture system proved to be optimum for large-scale expansion of hT-MSCs and production of tissue-engineered cardiovascular grafts, without compromising the quality of cells. This study demonstrated the feasibility of engineering clinical-grade living autologous replacement grafts using hT-MSCs and proved the compatibility of these grafts for in vivo implantation in a left pulmonary artery position.

Background: Living grafts produced by combining autologous heart-resident stem/progenitor cells and tissue engineering could provide a new therapeutic option for definitive correction of congenital heart disease. The aim of the study was to investigate the antigenic profile, expansion/differentiation capacity, paracrine activity, and pro-angiogenic potential of cardiac pericytes and to assess their engrafting capacity in clinically certified prosthetic grafts., Methods and Results: CD34(pos) cells, negative for the endothelial markers CD31 and CD146, were identified by immunohistochemistry in cardiac leftovers from infants and children undergoing palliative repair of congenital cardiac defects. Following isolation by immunomagnetic bead-sorting and culture on plastic in EGM-2 medium supplemented with growth factors and serum, CD34(pos)/CD31(neg) cells gave rise to a clonogenic, highly proliferative (>20 million at P5), spindle-shape cell population. The following populations were shown to expresses pericyte/mesenchymal and stemness markers. After exposure to differentiation media, the expanded cardiac pericytes acquired markers of vascular smooth muscle cells, but failed to differentiate into endothelial cells or cardiomyocytes. However, in Matrigel, cardiac pericytes form networks and enhance the network capacity of endothelial cells. Moreover, they produce collagen-1 and release chemo-attractants that stimulate the migration of c-Kit(pos) cardiac stem cells. Cardiac pericytes were then seeded onto clinically approved xenograft scaffolds and cultured in a bioreactor. After 3 weeks, fluorescent microscopy showed that cardiac pericytes had penetrated into and colonized the graft., Conclusions: These findings open new avenues for cellular functionalization of prosthetic grafts to be applied in reconstructive surgery of congenital heart disease., (© 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Gab1 (Grb2 associated binding protein 1) is a member of the scaffolding/docking proteins (Gab1, Gab2, and Gab3). It is required for fibroblast cell survival and maintaining cardiac function. Very little is known about human Gab1 expression in response to chronic hypoxia. The present study examined the hypothesis that hypoxia regulates Gab1 expression in human paediatric myocardium and cultured rat cardiomyocytes. Here we showed that Gab1 is expressed in myocardial tissue in acyanotic and cyanotic children with congenital heart defects. Gab1 protein was upregulated in cyanotic compared to acyanotic hearts suggesting that Gab1 upregulation is a component of the survival program initiated by hypoxia in cyanotic children. The expression of other Gab1 interacting partners was not affected by hypoxia and Gab1 regulation. Additionally, using an in vitro model, we demonstrated that overexpressing Gab1 in neonatal cardiomyocytes, under hypoxic condition, resulted in the reduction of apoptosis suggesting a role for this protein in cardiomyocyte survival. Altogether, our data provide strong evidence that Gab1 is important for heart cell survival following hypoxic stress.

Objective: Single-ventricle patients undergoing pediatric heart surgery are a high-risk group owing to reoxygenation injury during cardiopulmonary bypass (CPB). The present study investigated the effects of controlled reoxygenation CPB on biomarkers of organ damage, inflammation, stress, and long-term functional outcomes in cyanotic patients with either a single or double ventricle during open heart surgery., Methods: Cyanotic patients with either a single (n = 32) or double (n = 47) ventricle undergoing surgical correction were randomized to receive CPB using either standard oxygen levels or controlled reoxygenation. The markers of cardiac injury, inflammation, stress, and cerebral and hepatic injury were measured preoperatively, at 10 and 30 minutes after starting CPB, and at 10 minutes and 4 and 24 hours after CPB. The data were analyzed using a mixed regression model., Results: No difference was found in the pre- or intraoperative characteristics between the standard and controlled reoxygenation CPB groups for single- or double-ventricle patients. In the single-ventricle patients, controlled reoxygenation CPB significantly (P < .05) decreased the markers of organ damage, inflammation, stress, and oxidative stress. In contrast, the markers of inflammation and cardiac injury were not altered by controlled reoxygenation CPB in the double-ventricle patients., Conclusions: Controlled reoxygenation CPB decreased the markers of organ damage, stress, inflammation, and oxidative stress in single-ventricle patients undergoing cardiac surgery., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objectives: This study investigates the effects of controlled reoxygenation cardiopulmonary bypass on oxidative stress, inflammatory response, and organ function in children undergoing repair of cyanotic congenital heart defects., Methods: Sixty-seven cyanotic patients (median age 15 months, interquartile range 6-49 months) undergoing corrective cardiac surgery were randomized to receive either controlled normoxic (50-0 mm Hg; n = 35) or hyperoxic (150-180 mm Hg; n = 32) cardiopulmonary bypass. Troponin I and 8-isoprostane, C3a, interleukins 6, 8, and 10, cortisol, protein S100, and alpha-glutamate transferase were measured preoperatively and 10 and 30 minutes after starting bypass, on removal of the aortic crossclamp, and 12 and 24 hours thereafter., Results: Overall, troponin I and 8-isoprostane levels were lower in the controlled normoxic group (-29%, 95% CI -48% to -3%, P = .03, and -26%, 95% CI -44% to -2%, P = .03, respectively). Protein S100 release was also lower in the normoxic group 10 minutes after starting bypass (-26%, 95% CI -40% to -9%, P = .005) and 10 minutes after aortic crossclamp removal (-23%, 95% CI -38% to -3%, P = .02, respectively), but similar at other time points in the two groups (P >or= .17). The alpha-glutamate transferase release was significantly lower in the normoxic group 10 minutes after aortic crossclamp removal (-28%, 95% CI -44% to -9%, P = .006, respectively) but was similar at other times (P >or= .11). Release of C3a, interleukins 6, 8, and 10, and cortisol was similar in the two groups throughout (P >or= .15)., Conclusion: Controlled reoxygenation on starting cardiopulmonary bypass is associated with reduced myocardial damage, oxidative stress, and cerebral and hepatic injury compared with hyperoxic bypass and similar whole body inflammatory and stress response in cyanotic children undergoing open cardiac surgery.