RATIONALE:Autologous bone marrow mesenchymal stem cells (MSCs) and c-kit cardiac progenitor cells (CPCs) are 2 promising cell types being evaluated for patients with heart failure (HF) secondary to ...ischemic cardiomyopathy. No information is available in humans about the relative efficacy of MSCs and CPCs and whether their combination is more efficacious than either cell type alone.
OBJECTIVE:CONCERT-HF (Combination of Mesenchymal and c-kit Cardiac Stem Cells As Regenerative Therapy for Heart Failure) is a phase II trial aimed at elucidating these issues by assessing the feasibility, safety, and efficacy of transendocardial administration of autologous MSCs and CPCs, alone and in combination, in patients with HF caused by chronic ischemic cardiomyopathy (coronary artery disease and old myocardial infarction).
METHODS AND RESULTS:Using a randomized, double-blinded, placebo-controlled, multicenter, multitreatment, and adaptive design, CONCERT-HF examines whether administration of MSCs alone, CPCs alone, or MSCs+CPCs in this population alleviates left ventricular remodeling and dysfunction, reduces scar size, improves quality of life, or augments functional capacity. The 4-arm design enables comparisons of MSCs alone with CPCs alone and with their combination. CONCERT-HF consists of 162 patients, 18 in a safety lead-in phase (stage 1) and 144 in the main trial (stage 2). Stage 1 is complete, and stage 2 is currently randomizing patients from 7 centers across the United States.
CONCLUSIONS:CONCERT-HF will provide important insights into the potential therapeutic utility of MSCs and CPCs, given alone and in combination, for patients with HF secondary to ischemic cardiomyopathy.
CLINICAL TRIAL REGISTRATION:URLhttp://www.clinicaltrials.gov. Unique identifierNCT02501811.
The regenerative capacity of the heart after myocardial infarction is limited. Our previous study showed that ectopic introduction of 4 cell cycle factors (4F; CDK1 cyclin-dependent kinase 1, CDK4 ...cyclin-dependent kinase 4, CCNB cyclin B1, and CCND cyclin D1) promotes cardiomyocyte proliferation in 15% to 20% of infected cardiomyocytes in vitro and in vivo and improves cardiac function after myocardial infarction in mice.
Using temporal single-cell RNA sequencing, we aimed to identify the necessary reprogramming stages during the forced cardiomyocyte proliferation with 4F on a single cell basis. Using rat and pig models of ischemic heart failure, we aimed to start the first preclinical testing to introduce 4F gene therapy as a candidate for the treatment of ischemia-induced heart failure.
Temporal bulk and single-cell RNA sequencing and further biochemical validations of mature human induced pluripotent stem cell-derived cardiomyocytes treated with either LacZ or 4F adenoviruses revealed full cell cycle reprogramming in 15% of the cardiomyocyte population at 48 hours after infection with 4F, which was associated mainly with sarcomere disassembly and metabolic reprogramming (n=3/time point/group). Transient overexpression of 4F, specifically in cardiomyocytes, was achieved using a polycistronic nonintegrating lentivirus (NIL) encoding 4F; each is driven by a TNNT2 (cardiac troponin T isoform 2) promoter (TNNT2-4Fpolycistronic-NIL). TNNT2-4Fpolycistronic-NIL or control virus was injected intramyocardially 1 week after myocardial infarction in rats (n=10/group) or pigs (n=6-7/group). Four weeks after injection, TNNT2-4Fpolycistronic-NIL-treated animals showed significant improvement in left ventricular ejection fraction and scar size compared with the control virus-treated animals. At 4 months after treatment, rats that received TNNT2-4Fpolycistronic-NIL still showed a sustained improvement in cardiac function and no obvious development of cardiac arrhythmias or systemic tumorigenesis (n=10/group).
This study provides mechanistic insights into the process of forced cardiomyocyte proliferation and advances the clinical feasibility of this approach by minimizing the oncogenic potential of the cell cycle factors owing to the use of a novel transient and cardiomyocyte-specific viral construct.
Background The EXPEDITION study addressed the efficacy and safety of inhibiting the sodium hydrogen exchanger isoform-1 (NHE-1) by cariporide in the prevention of death or myocardial infarction (MI) ...in patients undergoing coronary artery bypass graft surgery. The premise was that inhibition of NHE-1 limits intracellcular Na accumulation and thereby limits Na/Ca-exchanger–mediated calcium overload to reduce infarct size. Methods High-risk coronary artery bypass graft surgery patients (n = 5,761) were randomly allocated to receive either intravenous cariporide (180 mg in a 1-hour preoperative loading dose, then 40 mg per hour over 24 hours and 20 mg per hour over the subsequent 24 hours) or placebo. The primary composite endpoint of death or MI was assessed at 5 days, and patients were followed for as long as 6 months. Results At 5 days, the incidence of death or MI was reduced from 20.3% in the placebo group to 16.6% in the treatment group ( p = 0.0002). Paradoxically, MI alone declined from 18.9% in the placebo group to 14.4% in the treatment group ( p = 0.000005), while mortality alone increased from 1.5% in the placebo group to 2.2% with cariporide ( p = 0.02). The increase in mortality was associated with an increase in cerebrovascular events. Unlike the salutary effects that were maintained at 6 months, the difference in mortality at 6 months was not significant. Conclusions The EXPEDITION study is the first phase III myocardial protection trial in which the primary endpoint was achieved and proof of concept demonstrated. As a result of increased mortality associated with an increase in cerebrovascular events, it is unlikely that cariporide will be used clinically. The findings suggest that sodium hydrogen exchanger isoform-1 inhibition holds promise for a new class of drugs that could significantly reduce myocardial injury associated with ischemia-reperfusion injury.
Overeating and obesity are major health problems in developed countries. Caloric restriction (CR) can counteract the deleterious aspects of obesity-related diseases and prolong lifespan. We have ...demonstrated that short-term CR improves myocardial ischemic tolerance and increases adiponectin levels. Here, we investigated the specific role of adiponectin in CR-induced cardioprotection.
Adiponectin antisense transgenic (Ad-AS) mice and wild-type (WT) mice were randomly assigned to a group fed ad libitum and a CR group (90% of caloric intake of ad libitum for 3 weeks, then 65% for 2 weeks). Isolated perfused mouse hearts were subjected to 25 minutes of ischemia, followed by 60 minutes of reperfusion. CR increased serum adiponectin levels by 84% in WT mice. Gel filtration analysis of the oligomeric complex distribution showed that CR produced a marked increase in the high-molecular-weight complex of adiponectin in WT mice; in contrast, CR did not change serum adiponectin levels or their oligomeric pattern in Ad-AS mice. CR improved the recovery of left ventricular function after ischemia/reperfusion and limited infarct size in WT mice; these effects were completely abrogated in Ad-AS mice. CR also increased the phosphorylated form of AMP-activated protein kinase and acetyl-CoA carboxylase in WT but not in Ad-AS mice. Recombinant adiponectin restored CR-induced cardioprotection in Ad-AS mice, and inhibition of AMP-activated protein kinase phosphorylation completely abrogated CR-induced cardioprotection in WT mice.
The cardioprotective effects of short-term CR are mediated by increased production of adiponectin and the associated activation of AMP-activated protein kinase.
The myocardium consists of numerous cell types embedded in organized layers of ECM (extracellular matrix) and requires an intricate network of blood and lymphatic vessels and nerves to provide ...nutrients and electrical coupling to the cells. Although much of the focus has been on cardiomyocytes, these cells make up <40% of cells within a healthy adult heart. Therefore, repairing or regenerating cardiac tissue by merely reconstituting cardiomyocytes is a simplistic and ineffective approach. In fact, when an injury occurs, cardiac tissue organization is disrupted at the level of the cells, the tissue architecture, and the coordinated interaction among the cells. Thus, reconstitution of a functional tissue must reestablish electrical and mechanical communication between cardiomyocytes and restore their surrounding environment. It is also essential to restore distinctive myocardial features, such as vascular patency and pump function. In this article, we review the current status, challenges, and future priorities in cardiac regenerative or reparative medicine. In the first part, we provide an overview of our current understanding of heart repair and comment on the main contributors and mechanisms involved in innate regeneration. A brief section is dedicated to the novel concept of rejuvenation or regeneration, which we think may impact future development in the field. The last section describes regenerative therapies, where the most advanced and disruptive strategies used for myocardial repair are discussed. Our recommendations for priority areas in studies of cardiac regeneration or repair are summarized in and .
The in vivo studies of myocardial infarct using c-ki⁺/Lin⁻ cardiac stem cells (CSCs) are still in the early stage with margin or no beneficial effects for cardiac function. One of the potential ...reasons may be related to the absence of fully understanding the properties of these cells both in vitro and in vivo. In the present study, we aimed to systematically examine how CSCs adapted to in vitro cell processes and whether there is any cell contamination after long-term culture. Human CSCs were enzymatically isolated from the atrial appendages of patients. The fixed tissue sections, freshly isolated or cultured CSCs were then used for identification of c-kit⁺/Lin⁻ cells, detection of cell contamination, or differentiation of cardiac lineages. By specific antibody staining, we demonstrated that tissue sections from atrial appendages contained less than 0.036% c-kit⁺/Lin⁻ cells. For the first time, we noted that without magnetic activated cell sorting (MACS), the percentages of c-kit⁺/Lin⁻ cells gradually increased up to ∼40% during continuously culture between passage 2 to 8, but could not exceed >80% unless c-kit MACS was carried out. The resulting c-kit⁺/Lin⁻ cells were negative for CD34, CD45, CD133, and Lin markers, but positive for KDR and CD31 in few patients after c-kit MACS. Lin depletion seemed unnecessary for enrichment of c-kit⁺/Lin⁻ cell population. Following induced differentiation, c-kit⁺/Lin⁻ CSCs demonstrated strong differentiation towards cardiomyocytes but less towards smooth and endothelial cells. We concluded that by using an enzymatic dissociation method, a large number, or higher percentage, of relative pure human CSCs with stable expression of c-kit⁺ could be obtained from atrial appendage specimens within ∼4 weeks following c-kit MACS without Lin depletion. This simple but cost-effective approach can be used to obtain enough numbers of stably-expressed c-kit⁺/Lin⁻ cells for clinical trials in repairing myocardial infarction.
Stem Cell Niches in the Adult Mouse Heart Urbanek, Konrad; Cesselli, Daniela; Rota, Marcello ...
Proceedings of the National Academy of Sciences - PNAS,
06/2006, Letnik:
103, Številka:
24
Journal Article
Recenzirano
Odprti dostop
Cardiac stem cells (CSCs) have been identified in the adult heart, but the microenvironment that protects the slow-cycling, undifferentiated, and self-renewing CSCs remains to be determined. We ...report that the myocardium possesses interstitial structures with the architectural organization of stem cell niches that harbor long-term BrdU-retaining cells. The recognition of long-term label-retaining cells provides functional evidence of resident CSCs in the myocardium, indicating that the heart is an organ regulated by a stem cell compartment. Cardiac niches contain CSCs and lineage-committed cells, which are connected to supporting cells represented by myocytes and fibroblasts. Connexins and cadherins form gap and adherens junctions at the interface of CSCs-lineage-committed cells and supporting cells. The undifferentiated state of CSCs is coupled with the expression of a4-integrin, which colocalizes with the α₂-chain of laminin and fibronectin. CSCs divide symmetrically and asymmetrically, but asymmetric division predominates, and the replicating CSC gives rise to one daughter CSC and one daughter committed cell. By this mechanism of growth kinetics, the pool of primitive CSCs is preserved, and a myocyte progeny is generated together with endothelial and smooth muscle cells. Thus, CSCs regulate myocyte turnover that is heterogeneous across the heart, faster at the apex and atria, and slower at the base-midregion of the ventricle.
The possibility that adult bone marrow cells (BMCs) retain a remarkable degree of developmental plasticity and acquire the cardiomyocyte lineage after infarction has been challenged, and the notion ...of BMC transdifferentiation has been questioned. The center of the controversy is the lack of unequivocal evidence in favor of myocardial regeneration by the injection of BMCs in the infarcted heart. Because of the interest in cell-based therapy for heart failure, several approaches including gene reporter assay, genetic tagging, cell genotyping, PCR-based detection of donor genes, and direct immunofluorescence with quantum dots were used to prove or disprove BMC transdifferentiation. Our results indicate that BMCs engraft, survive, and grow within the spared myocardium after infarction by forming junctional complexes with resident myocytes. BMCs and myocytes express at their interface connexin 43 and N-cadherin, and this interaction may be critical for BMCs to adopt the cardiomyogenic fate. With time, a large number of myocytes and coronary vessels are generated. Myocytes show a diploid DNA content and carry, at most, two sex chromosomes. Old and new myocytes show synchronicity in calcium transients, providing strong evidence in favor of the functional coupling of these two cell populations. Thus, BMCs transdifferentiate and acquire the cardiomyogenic and vascular phenotypes restoring the infarcted heart. Together, our studies reveal that locally delivered BMCs generate de novo myocardium composed of integrated cardiomyocytes and coronary vessels. This process occurs independently of cell fusion and ameliorates structurally and functionally the outcome of the heart after infarction.
Heme oxygenase-1 (HO-1) is one of the most powerful cytoprotective proteins known. The goal of this study was to explore the effects of HO-1 in c-kit-positive cardiac cells (CPCs). Lin
/c-kit
CPCs ...were isolated and expanded from wild-type (WT), HO-1 transgenic (TG), or HO-1 knockout (KO) mouse hearts. Compared with WT CPCs, cell proliferation was significantly increased in HO-1
CPCs and decreased in HO-1
CPCs. HO-1
CPCs also exhibited a marked increase in new DNA synthesis during the S-phase of cell division, not only under normoxia (21% O
) but after severe hypoxia (1% O
for 16 h). These properties of HO-1
CPCs were associated with nuclear translocation (and thus activation) of Nrf2, a key transcription factor that regulates antioxidant genes, and increased protein expression of Ec-SOD, the only extracellular antioxidant enzyme. These data demonstrate that HO-1 upregulates Ec-SOD in CPCs and suggest that this occurs via activation of Nrf2, which thus is potentially involved in the crosstalk between two antioxidants, HO-1 in cytoplasm and Ec-SOD in extracellular matrix. Overexpression of HO-1 in CPCs may improve the survival and reparative ability of CPCs after transplantation and thus may have potential clinical application to increase efficacy of cell therapy.
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