[Usefulness of intracoronary therapy with progenitor cells in patients with dilated cardiomyopathy: Bridge or alternative to heart transplantation?]. An Pediatr (Barc). 2011;74:218-225. [PMID: 21398194 DOI: 10.1016/j.anpedi.2011.02.013]

An overview of stem cell therapy for paediatric heart failure

Significant achievements in paediatric cardiology, surgical treatment and intensive care of congenital heart disease have drastically changed clinical outcomes for paediatric patients. Nevertheless, late-onset heart failure in children after staged surgeries still remains a serious concern in the medical community. Heart transplantation is an option for treatment; however, the shortage of available organs is a persistent problem in many developed countries. In order to resolve these issues, advanced technologies, such as innovative mechanical circulatory support devices and regenerative therapies, are strongly desired. Accumulated evidence regarding cell-based cardiac regenerative therapies has suggested their safety and efficacy in treating adult heart failure. Given that young children seem to have a higher regenerative capacity than adults, stem cell-based therapies appear a promising treatment option for paediatric heart failure as well. Based on the findings from past trials and studies, we present the potential of various different types of stem cells, ranging from bone marrow mononuclear cells to cardiosphere-derived stem cells for use in paediatric cell-based therapies. Here, we assess both the current challenges associated with cell-based therapies and novel strategies that may be implemented in the future to advance stem cell therapy in the paediatric population.

Safety and efficacy of cell therapies in pediatric heart disease: a systematic review and meta-analysis

BACKGROUND

Adult clinical trials have reported safety and the therapeutic potential of stem cells for cardiac disease. These observations have now translated to the pediatric arena. We conducted a meta-analysis to assess safety and efficacy of cell-based therapies in animal and human studies of pediatric heart disease.

METHODS AND RESULTS

A literature search was conducted to examine the effects of cell-based therapies on: (i) safety and (ii) cardiac function. In total, 18 pre-clinical and 13 human studies were included. Pre-clinical: right ventricular dysfunction was the most common animal model (80%). Cardiac-derived (28%) and umbilical cord blood (24%) cells were delivered intravenously (36%) or intramyocardially (35%). Mortality was similar between cell-based and control groups (OR 0.94; 95% CI 0.05, 17.41). Cell-based treatments preserved ejection fraction by 6.9% (p < 0.01), while intramyocardial at a dose of 1-10 M cells/kg optimized ejection fraction. Clinical: single ventricle physiology was the most common cardiac disease (n = 9). Cardiac tissue was a frequent cell source, dosed from 3.0 × 105 to 2.4 × 107 cells/kg. A decrease in adverse events occurred in the cell-based cohort (OR 0.17, p < 0.01). Administration of cell-based therapies improved ejection fraction (MD 4.84; 95% CI 1.62, 8.07; p < 0.01).

CONCLUSIONS

In this meta-analysis, cell-based therapies were safe and improved specific measures of cardiac function. Implications from this review may provide methodologic recommendations (source, dose, route, timing) for future clinical trials. Of note, many of the results described in this study pattern those seen in adult stem cell reviews and meta-analyses.

Regenerative therapies in young hearts with structural or congenital heart disease

Pediatric heart failure (HF) is rare. The prognosis is generally poor. HF is most frequently related to cardiomyopathy or congenital heart disease (CHD). Associated phenotypes are HF with preserved (HFpEF) or reduced ejection fraction (HFrEF); both in children with biventricular or univentricular circulation. Cardiac growth, differentiation, proliferation and consecutively regenerative and repair mechanisms are inversely related to the patient's age; edaphic and circulating cardiac progenitor cells as well; in sum, there are enormous endogenous potentials repairing a diseased heart in particular in young children. Efforts supporting pediatric cardiac regeneration are clearly justified; cell-based therapies have been addressed in small series of children with end-stage HF of either the left or right ventricle, more recently in randomized clinical trials. Different cell populations like autologous bone marrow mononuclear cells, progenitor cells or cardiac derived cells have been injected into coronaries or directly into the myocardium. Beneficial at least transient improvement of cardiac function was observed in patients with dilative cardiomyopathy and CHD, mainly hypoplastic left heart syndrome (HLHS). Cellular repopulation and possibly more crucial, paracrine effects contributed in slowing down progression of pediatric end-stage HF. Our review summarizes the current knowledge in different scenarios of HF by cell-based cardiac therapies in critically ill children. Based on the actual clinical experience future work to distinguish responders from non-responders among other refinements will lead to individualized precision treatment of HF in children, what means a lot to a child on a long list waiting for heart transplantation (HTX).

Clinical cardiac regenerative studies in children

Although the incidence of pediatric heart failure is low, the mortality is relatively high, with severe clinical symptoms requiring repeated hospitalization or intensive care treatment in the surviving patients. Cardiac biopsy specimens have revealed a higher number of resident human cardiac progenitor cells, with greater proliferation and differentiation capacity, in the neonatal period as compared with adults, demonstrating the regeneration potential of the young heart, with rising interest in cardiac regeneration therapy in critically ill pediatric patients. We review here the available literature data, searching the MEDLINE, Google Scholar and EMBASE database for completed, and www.clinicaltrials.gov homepage for ongoing studies involving pediatric cardiac regeneration reports. Because of difficulties conducting randomized blinded clinical trials in pediatric patients, mostly case reports or cohort studies with a limited number of individuals have been published in the field of pediatric regenerative cardiology. The majority of pediatric autologous cell transplantations into the cardiac tissue have been performed in critically ill children with severe or terminal heart failure. Congenital heart disease, myocarditis, and idiopathic hypertrophic or dilated cardiomyopathy leading to congestive heart failure are some possible areas of interest for pediatric cardiac regeneration therapy. Autologous bone marrow mononuclear cells, progenitor cells, or cardiospheres have been applied either intracoronary or percutaneously intramyocardially in severely ill children, leading to a reported clinical benefit of cell-based cardiac therapies. In conclusion, compassionate use of autologous stem cell administration has led to at least short-term improvement in heart function and clinical stability in the majority of the critically ill pediatric patients.

Cardiac regeneration in children

Very young mammals have an impressive cardiac regeneration capacity. In contrast, cardiac regeneration is very limited in adult humans. The hearts of young children have a higher regenerative capacity compared with adults, as, for example, seen after surgical correction of an anomalous left coronary artery arising from the pulmonary artery or in children with univentricular hearts, who present enormous morphological changes after volume unloading. In addition, the enormous regenerative potential of growing children's hearts is reflected in the spontaneous courses of children with severely deteriorated cardiac function (e.g., patients with dilated cardiomyopathy). The extent of this regenerative capacity and its time dependency remain to be elucidated in the future and should be exploited to improve the treatment of children with severe heart insufficiency.

Follow-up of the patients after stem cell transplantation for pediatric dilated cardiomyopathy

Dilated cardiomyopathy is a serious problem in pediatric cardiology. Despite the relatively low incidence, the mortality is high. The conservative therapy does not improve the prognosis, and possibilities of heart transplantation are limited. There are multiple trials of use of stem cells for ischemic heart disease in the adult population. This allows us to believe that the method has perspectives in pediatric cardiology. We performed the cell therapy for seven patients, six of them had complete one yr follow-up after procedure. Five to 30 milliliters of bone marrow was aspirated from the iliac crest and 17 to 122 million BMCs were isolated. The average basal EF was 33.5%. We observed increasing of EF up to 54% (=9.54, p=0.00154) in a 6-month period and up to 54.5% (=10.82, p= 0.00315) after one yr. The changes of LVEDV also were observed. The LVEDV decreased in average per 13.05%. There were no observed side effects or heart rhythm disorders. Intramyocardial administration of bone marrow-derived progenitor cells proved to be a technically feasible and safe method. Up until now, the results obtained have been promising and we suppose that bone marrow-derived progenitor cell intramyocardial transplantation can be used.

Resveratrol and adipose-derived mesenchymal stem cells are effective in the prevention and treatment of doxorubicin cardiotoxicity in rats

Anthracyclines can cause severe cardiac toxicity leading to heart failure. The aim of this study was to determine the effects of cardioprotective polyphenolic compound resveratrol (RES) and adipose-derived mesenchymal stem cells (ADMSCs) on cardiac tissue of rats treated with doxorubicin (DOX). Forty-two female and three male Wistar-Albino rats were included in the study. The study groups and the control groups were as follows: Group I: DOX; Group II: DOX + RES; Group III: DOX + ADMSCs; Group IV: DOX + RES + ADMSCs; Group V: Sham operation; and Group VI: normal saline. ADMSCs obtained from male rats were defined with stem cell markers [CD11b/c(-), CD45(-), CD90(+), CD44(+), and CD49(+)]. DOX 12 mg/kg intraperitoneally (i.p.) was injected as a single dose in female rats. Resveratrol 100 mg/kg was injected three times i.p. in Groups II and IV. ADMSCs 2 × 10(6) cells/kg/dose were labeled with bromodeoxyuridine (BrdU) and injected i.p. for a total of three times in Groups III and IV. When the study was terminated after 4 weeks, the beating hearts were connected to a Langendorff setup and records were obtained for 30 minutes. Histopathological, immunhistochemical, and immunofluorescent examination with H&E, Troponin I, and BrdU stains were also performed. Also, ADMSCs were demonstrated in the myocardium of transplanted rats. Left ventricle functions and myocardial histology demonstrated significant impairment in DOX only group compared to groups with ADMSCs (P < .05). We suggest that RES and ADMSCs were successful in the prevention and treatment of the doxorubicin cardiomyopathy in rats. The hypothetical mechanisms of regeneration are multiple, including cell differentiation and autocrine/paracrine effects of ADMSCs.