Publications by authors named "Darcy L Difede"

: A loss of endogenous stem cells capable of tissue repair and regeneration drives the biological process that we recognize as "aging". Recovery of stem cell-mediated repair and regenerative functions in aged animals has been reported in murine heterochronic parabiosis experiments. : Herein we will review how pregnancy is an unusual form of heterochronic parabiosis, as the placenta prevents the exchange of most blood cells between parabionts.

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The U.S. Food and Drug Administration (FDA) provides guidance for expanded access to experimental therapies, which in turn plays an important role in the Twenty-first Century Cures Act mandate to advance cell-based therapy.

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Background: Despite limited human data, there is a growing interest in the use of stem cell therapy (SCT) for erectile dysfunction (ED).

Aim: To determine the effect of transendocardial stem cell injection on erectile function on men with cardiomyopathy and ED.

Methods: We used International Index of Erectile Function (IIEF) scores collected from men enrolled in 3 separate randomized controlled trials: Comparison of Allogeneic vs Autologous Bone Marrow-Derived Mesenchymal Stem Cells Delivered by Transendocardial Injection in Patients With Ischemic Cardiomyopathy (POSEIDON), Transendocardial Mesenchymal Stem Cells and Mononuclear Bone Marrow Cells for Ischemic Cardiomyopathy (TAC-HFT), and Dose Comparison Study of Allogeneic Mesenchymal Stem Cells in Patients With Ischemic Cardiomyopathy (TRIDENT).

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Background: Non-ischemic dilated cardiomyopathy (NIDCM) responds variably to intramyocardial injection of mesenchymal stem cells (MSCs). We hypothesized that NIDCM genotype may influence responsiveness to MSC therapy and performed genotyping on all patients in the POSEIDON-DCM trial.

Methods: POSEIDON-DCM patients (n = 34) underwent genetic sequence analysis and deletion/duplication testing.

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High-level quadriplegia is a devastating condition with limited treatment options. Bone marrow derived stem cells (BMSCs) are reported to have immunomodulatory and neurotrophic effects in spinal cord injury (SCI). We report a subject with complete C2 SCI who received three anatomically targeted intrathecal infusions of BMSCs under a single-patient expanded access investigational new drug (IND).

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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).

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Microgravity-induced alterations in the autonomic nervous system (ANS) contribute to derangements in both the mechanical and electrophysiological function of the cardiovascular system, leading to severe symptoms in humans following space travel. Because the ANS forms embryonically from neural crest (NC) progenitors, we hypothesized that microgravity can impair NC-derived cardiac structures. Accordingly, we conducted in vitro simulated microgravity experiments employing NC genetic lineage tracing in mice with cKit, Isl1nLacZ, and Wnt1-Cre reporter alleles.

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Background: Aging frailty, characterized by decreased physical and immunological functioning, is associated with stem cell depletion. Human allogeneic mesenchymal stem cells (allo-hMSCs) exert immunomodulatory effects and promote tissue repair.

Methods: This is a randomized, double-blinded, dose-finding study of intravenous allo-hMSCs (100 or 200-million [M]) vs placebo delivered to patients (n = 30, mean age 75.

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Despite advances in surgical technique and postoperative care, long-term survival of children born with hypoplastic left heart syndrome (HLHS) remains limited, with cardiac transplantation as the only alternative for patients with failing single ventricle circulations. Maintenance of systemic right ventricular function is crucial for long-term survival, and interventions that improve ventricular function and avoid or defer transplantation in patients with HLHS are urgently needed. We hypothesize that the young myocardium of the HLHS patient is responsive to the biological cues delivered by bone marrow-derived mesenchymal stem cells (MSCs) to improve and preserve right ventricle function.

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Rationale: Cell dose and concentration play crucial roles in phenotypic responses to cell-based therapy for heart failure.

Objective: To compare the safety and efficacy of 2 doses of allogeneic bone marrow-derived human mesenchymal stem cells identically delivered in patients with ischemic cardiomyopathy.

Methods And Results: Thirty patients with ischemic cardiomyopathy received in a blinded manner either 20 million (n=15) or 100 million (n=15) allogeneic human mesenchymal stem cells via transendocardial injection (0.

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Background: Impaired endogenous stem cell repair capacity is hypothesized to be a biologic basis of frailty. Therapies that restore regenerative capacity may therefore be beneficial. This Phase 1 study evaluated the safety and potential efficacy of intravenous, allogeneic, human mesenchymal stem cell (allo-hMSC)-based therapy in patients with aging frailty.

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Transendocardial stem cell injection in patients with ischemic cardiomyopathy (ICM) improves left ventricular function and structure but has ill-defined effects on ventricular arrhythmias. We hypothesized that mesenchymal stem cell (MSC) implantation is not proarrhythmic. Post hoc analyses were performed on ambulatory ECGs collected from the POSEIDON and TAC-HFT trials.

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Background: Although human mesenchymal stem cells (hMSCs) have been tested in ischemic cardiomyopathy, few studies exist in chronic nonischemic dilated cardiomyopathy (NIDCM).

Objectives: The authors conducted a randomized comparison of safety and efficacy of autologous (auto) versus allogeneic (allo) bone marrow-derived hMSCs in NIDCM.

Methods: Thirty-seven patients were randomized to either allo- or auto-hMSCs in a 1:1 ratio.

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Frailty is a syndrome associated with reduced physiological reserves that increases an individual's vulnerability for developing increased morbidity and/or mortality. While most clinical trials have focused on exercise, nutrition, pharmacologic agents, or a multifactorial approach for the prevention and attenuation of frailty, none have studied the use of cell-based therapies. We hypothesize that the application of allogeneic human mesenchymal stem cells (allo-hMSCs) as a therapeutic agent for individuals with frailty is safe and efficacious.

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An important stage in the development of any new therapeutic agent is establishment of the optimal dosage and route of administration. This can be particularly challenging when the treatment is a biologic agent that might exert its therapeutic effects via complex or poorly understood mechanisms. Multiple preclinical and clinical studies have shown paradoxical results, with inconsistent findings regarding the relationship between the cell dose and clinical benefit.

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Background: Both bone marrow-derived mesenchymal stem cells (MSCs) and c-kit(+) cardiac stem cells (CSCs) improve left ventricular remodeling in porcine models and clinical trials. Using xenogeneic (human) cells in immunosuppressed animals with acute ischemic heart disease, we previously showed that these 2 cell types act synergistically.

Objectives: To more accurately model clinical applications for heart failure, this study tested whether the combination of autologous MSCs and CSCs produce greater improvement in cardiac performance than MSCs alone in a nonimmunosuppressed porcine model of chronic ischemic cardiomyopathy.

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Background: Endothelial dysfunction, characterized by diminished endothelial progenitor cell (EPC) function and flow-mediated vasodilation (FMD), is a clinically significant feature of heart failure (HF). Mesenchymal stem cells (MSCs), which have pro-angiogenic properties, have the potential to restore endothelial function. Accordingly, we tested the hypothesis that MSCs increase EPC function and restore flow-mediated vasodilation (FMD).

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Background: The role of patient age in the efficacy of mesenchymal stem cell (MSC) therapy in ischemic cardiomyopathy (ICM) is controversial.

Objectives: This study sought to determine whether the therapeutic effect of culture-expanded MSCs persists, even in older subjects.

Methods: Patients with ICM who received MSCs via transendocardial stem cell injection (TESI) as part of the TAC-HFT (Transendocardial Autologous Cells in Ischemic Heart Failure) (n = 19) and POSEIDON (Percutaneous Stem Cell Injection Delivery Effects on Neomyogenesis) (n = 30) clinical trials were divided into 2 age groups: younger than 60 and 60 years of age and older.

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While accumulating clinical trials have focused on the impact of cell therapy in patients with acute myocardial infarction (MI) and ischemic cardiomyopathy, there are fewer efforts to examine cell-based therapy in patients with non-ischemic cardiomyopathy (NICM). We hypothesized that cell therapy could have a similar impact in NICM. The POSEIDON-DCM trial is a phase I/II trial designed to address autologous vs.

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Rationale: Although accumulating data support the efficacy of intramyocardial cell-based therapy to improve left ventricular (LV) function in patients with chronic ischemic cardiomyopathy undergoing CABG, the underlying mechanism and impact of cell injection site remain controversial. Mesenchymal stem cells (MSCs) improve LV structure and function through several effects including reducing fibrosis, neoangiogenesis, and neomyogenesis.

Objective: To test the hypothesis that the impact on cardiac structure and function after intramyocardial injections of autologous MSCs results from a concordance of prorecovery phenotypic effects.

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Importance: Whether culture-expanded mesenchymal stem cells or whole bone marrow mononuclear cells are safe and effective in chronic ischemic cardiomyopathy is controversial.

Objective: To demonstrate the safety of transendocardial stem cell injection with autologous mesenchymal stem cells (MSCs) and bone marrow mononuclear cells (BMCs) in patients with ischemic cardiomyopathy.

Design, Setting, And Patients: A phase 1 and 2 randomized, blinded, placebo-controlled study involving 65 patients with ischemic cardiomyopathy and left ventricular (LV) ejection fraction less than 50% (September 1, 2009-July 12, 2013).

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