A Phase 1 Open-Label Study of the Safety of Intravenous Allogeneic Neonatal Mesenchymal Cells (nMSCs) in Young Adult (1A) and Pediatric (1B) Patients With Dilated Cardiomyopathy (DCM)

Inclusion Criteria * Phase 1A: Age greater than or equal to 18 years and less than 30 years (≥18 years, \<30 years). * Phase 1B: Age greater than or equal to 4 years and less than 18 years (≥4 years, \<18 years) * Subjects must be able to sign their own consent for Phase 1A of the study. * Diagnosis of dilated cardiomyopathy (DCM) defined as * Any Congenital Cardiac Malformation with systemic ventricular systolic dysfunction; Idiopathic Cardiomyopathy; Familial/Inherited and/or Genetic Cardiomyopathy; History of Myocarditis; Acquired (Chemotherapy, Iatrogenic, Infection, Rheumatic, Nutritional); Ischemic (e.g. Kawasaki Disease, post-operative); Left ventricular noncompaction; Coronary Artery Disease * Left ventricular ejection fraction less than or equal to 45% documented by two-dimensional echocardiogram or cardiac MRI within the prior six months. * Left ventricular dilation as defined by echocardiography left ventricular and end-diastolic dimension Z score \> +2.0 * Biventricular physiology with systemic left ventricle * Must receive guideline directed heart failure as defined by the American Heart Association, American College of Cardiology, and Heart Failure Society of America 118 * Have been unresponsive or poorly responsive to at least 3 months of maximum guideline directed treatments. Exclusion Criteria * Listed for heart transplantation (as UNOS status 1A) or hospitalized while waiting for transplant (while on inotropes or with ventricular assist device) * Cardiovascular surgery of percutaneous intervention to palliate or correct congenital cardiovascular malformations within 3 months of the screening visit. Patients anticipated to undergo corrective heart surgery during the 12 months after entry into Part 1A/1B. * Previous heart transplant recipient * Unoperated primary obstructive or severe regurgitant valve (aortic, pulmonary, or tricuspid) disease, or significant systemic ventricular outflow obstruction or aortic arch obstruction. * Severe mitral valve disease * Restrictive or hypertrophic cardiomyopathy * Cardiogenic shock * Currently on extracorporeal membrane oxygenation support * Ventricular assist device support * Lethal, uncontrollable arrhythmia defined as an arrhythmia resulting in hemodynamic instability requiring need for defibrillation, continuous intravenous anti-arrhythmic medication or mechanical circulatory support * Patients with persistent atrial fibrillation requiring specific pharmacotherapy * Amyloidosis * Ischemic dilated cardiomyopathy * Clinical history of malignant neoplasm within 5 years (with the exception of curatively treated basal cell carcinoma, squamous cell carcinoma, or cervical carcinoma) * Serious neurologic disorder including loss of vision, stroke, or paralysis * High-grade pulmonary embolism requiring interventional catheter procedure or pulmonary hypertension requiring use of pulmonary vasodilators including phosphodiesterase inhibitor or nitric oxide * High-grade renal failure \[eGFR\<45\] mL/min/1.73 m2 - serum potassium \>5.3 mmol/L * Multiple organ failure * Non-cardiac condition that limits life span for \<1 year * Uncontrolled diabetes (HbA1c \>9%) at screening * Active infection (including endocarditis) requiring pharmacotherapy * Sepsis * Active hemorrhagic disease (e.g., gastrointestinal bleeding, injury) * History of cardiac transplantation * Immune system-altering medications, or immunosuppressive therapy at the time of enrolment or within the prior 12 weeks * Dystrophin-associated cardiomyopathy confirmed by standard cardiomyopathy panel testing * Confirmed myocarditis at time of screening * Elevated LFTs greater than 2 times upper limit of normal at time of consent * Elevated WBC greater than upper limit of normal as defined by local lab at time of consent * Presence of HLA antibodies specific for therapeutic study product * History of noncompliance, alcohol abuse, recreational drug use, or incarceration within the last year * Currently pregnant or breastfeeding