Autologous Umbilical Cord Blood-Derived Mononuclear Cell Therapy Promotes Cardiac Proliferation and Adaptation in a Porcine Model of Right Ventricle Pressure Overload.

Congenital heart diseases, including single ventricle circulations, are clinically challenging due to chronic pressure overload and the inability of the myocardium to compensate for lifelong physiological demands. To determine the clinical relevance of autologous umbilical cord blood-derived mononuclear cells (UCB-MNCs) as a therapy to augment cardiac adaptation following surgical management of congenital heart disease, a validated model system of right ventricular pressure overload due to pulmonary artery banding (PAB) in juvenile pigs has been employed. PAB in a juvenile porcine model and intramyocardial delivery of UCB-MNCs was evaluated in three distinct 12-week studies utilizing serial cardiac imaging and end-of-study pathology evaluations. PAB reproducibly induced pressure overload leading to chronic right ventricular remodeling including significant myocardial fibrosis and elevation of heart failure biomarkers. High-dose UCB-MNCs (3 million/kg) delivered into the right ventricular myocardium did not cause any detectable safety issues in the context of arrhythmias or abnormal cardiac physiology. In addition, this high-dose treatment compared with placebo controls demonstrated that UCB-MNCs promoted a significant increase in Ki-67-positive cardiomyocytes coupled with an increase in the number of CD31+ endothelium. Furthermore, the incorporation of BrdU-labeled cells within the myocardium confirmed the biological potency of the high-dose UCB-MNC treatment. Finally, the cell-based treatment augmented the physiological adaptation compared with controls with a trend toward increased right ventricular mass within the 12 weeks of the follow-up period. Despite these adaptations, functional changes as measured by echocardiography and magnetic resonance imaging did not demonstrate differences between cohorts in this surgical model system. Therefore, this randomized, double-blinded, placebo-controlled pre-clinical trial establishes the safety of UCB-MNCs delivered via intramyocardial injections in a dysfunctional right ventricle and validates the induction of cardiac proliferation and angiogenesis as transient paracrine mechanisms that may be important to optimize long-term outcomes for surgically repaired congenital heart diseases.

Autologous stem cell therapy for hypoplastic left heart syndrome: Safety and feasibility of intraoperative intramyocardial injections.

OBJECTIVES: Staged surgical palliation for hypoplastic left heart syndrome results in an increased workload on the right ventricle serving as the systemic ventricle. Concerns for cardiac dysfunction and long-term heart failure have generated interest in first-in-infant, cell-based therapies as an additional surgical treatment modality. METHODS: A phase 1 clinical trial was conducted to evaluate the safety and feasibility of direct intramyocardial injection of autologous umbilical cord blood-derived mononuclear cells in 10 infants with hypoplastic left heart syndrome at the time of stage II palliation. RESULTS: All 10 patients underwent successful stage II palliation and intramyocardial injection of umbilical cord blood-derived mononuclear cells. Operative mortality was 0%. There was a single adverse event related to cell delivery: An injection site epicardial bleed that required simple oversew. The cohort did not demonstrate any significant safety concerns over 6 months. Additionally, the treatment group did not demonstrate any reduction in cardiac function in the context of the study related intramyocardial injections of autologous cells. CONCLUSIONS: This phase 1 clinical trial showed that delivering autologous umbilical cord blood-derived mononuclear cells directly into the right ventricular myocardium during planned stage II surgical palliation for hypoplastic left heart syndrome was safe and feasible. Secondary findings of preservation of baseline right ventricular function throughout follow-up and normalized growth rates support the design of a phase 2b follow-up trial.

Ultrasound guided percutaneous common carotid artery access in piglets for intracoronary stem cell infusion.

In pigs, the deep location of the common carotid artery and overlying sternomastoideus muscle in the neck has led to the recommendation for a surgical cutdown for common carotid access, as opposed to minimally invasive techniques for vascular access. We sought to determine if direct percutaneous common carotid artery access in piglets is attainable. Seventeen piglets were anesthetized and intubated. Under two-dimensional and color flow Doppler ultrasound guidance, a 21 gauge needle was utilized to access the right common carotid artery. Following arterial puncture, the Seldinger technique was applied to place a 4 or 5 French introducer. Upon completion of cardiac catheterization with intracoronary stem cell infusion the introducer was removed and manual pressure was applied to prevent hematoma development. Successful access with an introducer was achieved in all 17 piglets. The average weight was 8.5 ± 1.7 kg. One piglet developed a hematoma with hemorrhaging from the catheterization site and was euthanized. This piglet was given bivalirudin for the procedure. After this incident, subsequent piglets were not given anticoagulation and no other complications occurred. Ultrasound guided percutaneous common carotid artery access in piglets is attainable in a safe, reliable, and reproducible manner when performed by microvascular experts.

Cell-Based Therapy for Myocardial Dysfunction After Fontan Operation in Hypoplastic Left Heart Syndrome.

Myocardial dysfunction after Fontan palliation for univentricular congenital heart disease is a challenging clinical problem. The medical treatment has a limited impact, with cardiac transplant being the ultimate management step. Cell-based therapies are evolving as a new treatment for heart failure. Phase 1 clinical trials using regenerative therapeutic strategies in congenital heart disease are ongoing. We report the first case of autologous bone marrow-derived mononuclear cell administration for ventricular dysfunction, 23 years after Fontan operation in a patient with hypoplastic left heart syndrome. The cells were delivered into the coronary circulation by cardiac catheterization. Ventricular size decreased and several parameters reflecting ventricular function improved, with maximum change noted 3 months after cell delivery. Such regenerative therapeutic options may help in delaying and preventing cardiac transplant.

Stem Cell Therapy and Congenital Heart Disease.

For more than a decade, stem cell therapy has been the focus of intensive efforts for the treatment of adult heart disease, and now has promise for treating the pediatric population. On the basis of encouraging results in the adult field, the application of stem cell-based strategies in children with congenital heart disease (CHD) opens a new therapy paradigm. To date, the safety and efficacy of stem cell-based products to promote cardiac repair and recovery in dilated cardiomyopathy and structural heart disease in infants have been primarily demonstrated in scattered clinical case reports, and supported by a few relevant pre-clinical models. Recently the TICAP trial has shown the safety and feasibility of intracoronary infusion of autologous cardiosphere-derived cells in children with hypoplastic left heart syndrome. A focus on preemptive cardiac regeneration in the pediatric setting may offer new insights as to the timing of surgery, location of cell-based delivery, and type of cell-based regeneration that could further inform acquired cardiac disease applications. Here, we review the current knowledge on the field of stem cell therapy and tissue engineering in children with CHD, and discuss the gaps and future perspectives on cell-based strategies to treat patients with CHD.

Human umbilical cord blood-derived mononuclear cells improve murine ventricular function upon intramyocardial delivery in right ventricular chronic pressure overload.

INTRODUCTION: Stem cell therapy has emerged as potential therapeutic strategy for damaged heart muscles. Umbilical cord blood (UCB) cells are the most prevalent stem cell source available, yet have not been fully tested in cardiac regeneration. Herein, studies were performed to evaluate the cardiovascular safety and beneficial effect of mononuclear cells (MNCs) isolated from human umbilical cord blood upon intramyocardial delivery in a murine model of right ventricle (RV) heart failure due to pressure overload. METHODS: UCB-derived MNCs were delivered into the myocardium of a diseased RV cardiac model. Pulmonary artery banding (PAB) was used to produce pressure overload in athymic nude mice that were then injected intramyocardially with UCB-MNCs (0.4×10^6 cells/heart). Cardiac functions were then monitored by telemetry, echocardiography, magnetic resonance imaging (MRI) and pathologic analysis of heart samples to determine the ability for cell-based repair. RESULTS: The cardio-toxicity studies provided evidence that UCB cell transplantation has a safe therapeutic window between 0.4 to 0.8 million cells/heart without altering QT or ST-segments or the morphology of electrocardiograph waves. The PAB cohort demonstrated significant changes in RV chamber dilation and functional defects consistent with severe pressure overload. Using cardiac MRI analysis, UCB-MNC transplantation in the setting of PAB demonstrated an improvement in RV structure and function in this surgical mouse model. The RV volume load in PAB-only mice was 24.09±3.9 compared to 11.05±2.09 in the cell group (mm3, P-value<0.005). The analysis of pathogenic gene expression (BNP, ANP, Acta1, Myh7) in the cell-transplanted group showed a significant reversal with respect to the diseased PAB mice with a robust increase in cardiac progenitor gene expression such as GATA4, Kdr, Mef2c and Nkx2.5. Histological analysis indicated significant fibrosis in the RV in response to PAB that was reduced following UCB-MNC's transplantation along with concomitant increased Ki-67 expression and CD31 positive vessels as a marker of angiogenesis within the myocardium. CONCLUSIONS: These findings indicate that human UCB-derived MNCs promote an adaptive regenerative response in the right ventricle upon intramyocardial transplantation in the setting of chronic pressure overload heart failure.

Safety and feasibility for pediatric cardiac regeneration using epicardial delivery of autologous umbilical cord blood-derived mononuclear cells established in a porcine model system.

Congenital heart diseases (CHDs) requiring surgical palliation mandate new treatment strategies to optimize long-term outcomes. Despite the mounting evidence of cardiac regeneration, there are no long-term safety studies of autologous cell-based transplantation in the pediatric setting. We aimed to establish a porcine pipeline to evaluate the feasibility and long-term safety of autologous umbilical cord blood mononuclear cells (UCB-MNCs) transplanted into the right ventricle (RV) of juvenile porcine hearts. Piglets were born by caesarean section to enable UCB collection. Upon meeting release criteria, 12 animals were randomized in a double-blinded fashion prior to surgical delivery of test article (n=6) or placebo (n=6). The UCB-MNC (3×10(6) cells per kilogram) or control (dimethyl sulfoxide, 10%) products were injected intramyocardially into the RV under direct visualization. The cohorts were monitored for 3 months after product delivery with assessments of cardiac performance, rhythm, and serial cardiac biochemical markers, followed by terminal necropsy. No mortalities were associated with intramyocardial delivery of UCB-MNCs or placebo. Two animals from the placebo group developed local skin infection after surgery that responded to antibiotic treatment. Electrophysiological assessments revealed no arrhythmias in either group throughout the 3-month study. Two animals in the cell-therapy group had transient, subclinical dysrhythmia in the perioperative period, likely because of an exaggerated response to anesthesia. Overall, this study demonstrated that autologous UCB-MNCs can be safely collected and surgically delivered in a pediatric setting. The safety profile establishes the foundation for cell-based therapy directed at the RV of juvenile hearts and aims to accelerate cell-based therapies toward clinical trials for CHD.