To demonstrate the safety of transendocardial stem cell injection (TESI) with autologous MSCs and BMCs in patients with ICM.• To assess prespecified outcomes of efficacy.

Background As mesenchymal stem cells (MSCs) induce proliferation and differentiation of c-kit+ cardiac stem cells (CSCs) in vivo and in vitro, we hypothesized that combining human (h)MSCs with c-kit+ hCSCs produces greater infarct size reduction compared to either cell administered alone after MI. Methods and Results Yorkshire swine underwent balloon occlusion of the LAD coronary artery followed by reperfusion, and were immunosuppressed after MI with cyclosporine and methylprednisolone. Intramyocardial injection of either: combination hCSCs/hMSCs (1M/200M, n=5), hCSCs alone (1M, n=5), hMSCs alone (200M, n=5), or placebo (PBS, n=5) was administered to the infarct border zones at 14 days post-MI. Phenotypic response to cell therapy was assessed by cardiac MRI and micromanometer conductance catheterization hemodynamics. While each cell therapy group had reduced MI size relative to placebo (p<0.05), the MI size reduction was 2-fold greater in combination vs. either cell therapy alone (p<0.05). Accompanying enhanced MI size reduction was substantial improvement in LV chamber compliance (end-diastolic pressure volume relationship, p<0.01) and contractility (preload recruitable stroke work and dP/dtmax, p<0.05) in combination treated swine. EF was restored to baseline in cell treated pigs, while placebo pigs had persistently depressed LV function (p<0.05). Immunohistochemistry showed 7-fold enhanced engraftment of stem cells in the combination therapy group vs. either cell type alone (P<0.001). Conclusions Combining hMSCs and hCSCs as a cell therapeutic enhances scar size reduction, and restores diastolic and systolic function toward normal after MI. Taken together these findings illustrate important biological interactions between c-kit+ CSCs and MSCs that enhance cell-based therapeutic responses.

Rationale Transcatheter, intramyocardial injections of bone marrow derived cell therapy produces reverse remodeling in large animal models of ischemic cardiomyopathy. Objective We used cardiac magnetic resonance imaging (CMR) in patients with LV dysfunction related to remote myocardial infarction (MI) to test the hypothesis that bone marrow progenitor cell injection cause functional recovery of scarred myocardium and reverse remodeling. Methods and Results Eight patients (age 57.2±13.3) received transendocardial, intramyocardial injection of autologous bone marrow progenitor cells (mononuclear or mesenchymal stem cells) in LV scar and border zone. All patients tolerated the procedure with no serious adverse events. CMR at 1-year demonstrated a decrease in end-diastolic volume (208.7±20.4 vs. 167.4±7.32mL; p=0.03), a trend towards decreased end-systolic volume (142.4±16.5 vs. 107.6±7.4mL; p=0.06), decreased infarct size (p<0.05), and improved regional LV function by peak Ecc in the treated infarct zone (-8.1±1.0 vs. -11.4±1.3; p=0.04). Improvements in regional function were evident at 3 months, while the changes in chamber dimensions were not significant until 6 months. Improved regional function in the infarct zone strongly correlated with reduction of EDV (r2=0.69, p=0.04) and ESV (r2=0.83, p=0.01). Conclusions These data suggest that transcatheter, intramyocardial injections of autologous bone marrow progenitor cells improve regional contractility of a chronic myocardial scar and these changes predict subsequent reverse remodeling. The findings support the potential clinical benefits of this new treatment strategy and ongoing randomized clinical trials.

Chitin is a ubiquitous polysaccharide in fungi, insects, and parasites. We hypothesized that chitin is a size-dependent regulator of innate immunity. To test this hypothesis, we characterized the effects of chitins of different sizes on murine bronchoalveolar or peritoneal macrophages. In these studies, large chitin fragments were inert, while both intermediate-sized chitin (40–70 μm) and small chitin (SC; &lt;40 μm, largely 2–10 μm) stimulated TNF elaboration. In contrast, only SC induced IL-10 elaboration. The effects of intermediate-sized chitin were mediated by pathways that involve TLR2, dectin-1, and NF-κB. In contrast, the effects of SC were mediated by TLR2-dependent and -independent, dectin-1-dependent pathways that involved the mannose receptor and spleen tyrosine kinase. Chitin contains size-dependent pathogen-associated molecular patterns that stimulate TLR2, dectin-1, and the mannose receptor, differentially activate NF-κB and spleen tyrosine kinase, and stimulate the production of pro- and anti-inflammatory cytokines.

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Strategies to increase enrollment in patient portals need to ensure patients understand patient portal features and receive follow-up reminders. Interventions to reduce racial disparities in enrollment must address attitudinal barriers and not focus solely on improving access.

Sustainable and reproducible large animal models that closely replicate the clinical sequelae of myocardial infarction (MI) are important for the translation of basic science research into bedside medicine. Swine are well accepted by the scientific community for cardiovascular research, and they represent an established animal model for preclinical trials for US Food and Drug Administration (FDA) approval of novel therapies. Here we present a protocol for using porcine models of MI created with a closed-chest coronary artery occlusion-reperfusion technique. This creates a model of MI encompassing the anteroapical, lateral and septal walls of the left ventricle. This model infarction can be easily adapted to suit individual study design and enables the investigation of a variety of possible interventions. This model is therefore a useful tool for translational research into the pathophysiology of ventricular remodeling and is an ideal testing platform for novel biological approaches targeting regenerative medicine. This model can be created in approximately 8–10 h.

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