Phase 3 DREAM-HF Trial of Mesenchymal Precursor Cells in Chronic Heart Failure.

Advanced heart failure (HF) is a progressive disease characterized by recurrent hospitalizations and high risk of mortality. Indeed, outcomes in late stages of HF approximate those seen in patients with various aggressive malignancies. Clinical trials assessing beneficial outcomes of new treatments in patients with cancer have used innovative approaches to measure impact on total disease burden or surrogates to assess treatment efficacy. Although most cardiovascular outcomes trials continue to use time-to-first event analyses to assess the primary efficacy end point, such analyses do not adequately reflect the impact of new treatments on the totality of the chronic disease burden. Consequently, patient enrichment and other strategies for ongoing clinical trial design, as well as new statistical methodologies, are important considerations, particularly when studying a population with advanced chronic HF. The DREAM-HF trial (Double-Blind Randomized Assessment of Clinical Events With Allogeneic Mesenchymal Precursor Cells in Advanced Heart Failure) is an ongoing, randomized, sham-controlled phase 3 study of the efficacy and safety of mesenchymal precursor cells as immunotherapy in patients with advanced chronic HF with reduced ejection fraction. Mesenchymal precursor cells have a unique multimodal mechanism of action that is believed to result in polarization of proinflammatory type 1 macrophages in the heart to an anti-inflammatory type 2 macrophage state, inhibition of maladaptive adverse left ventricular remodeling, reversal of cardiac and peripheral endothelial dysfunction, and recovery of deranged vasculature. The objective of DREAM-HF is to confirm earlier phase 2 results and evaluate whether mesenchymal precursor cells will reduce the rate of nonfatal recurrent HF-related major adverse cardiac events while delaying or preventing progression of HF to terminal cardiac events. DREAM-HF is an example of an ongoing contemporary events-driven cardiovascular cell-based immunotherapy study that has utilized the concepts of baseline disease enrichment, prognostic enrichment, and predictive enrichment to improve its efficiency by using accumulating data from within as well as external to the trial. Adaptive enrichment designs and strategies are important components of a rational approach to achieve clinical research objectives in shorter clinical trial timelines and with increased cost-effectiveness without compromising ethical standards or the overall statistical integrity of the study. The DREAM-HF trial also presents an alternative approach to traditional composite time-to-first event primary efficacy end points. Statistical methodologies such as the joint frailty model provide opportunities to expand the scope of events-driven HF with reduced ejection fraction clinical trials to utilize time to recurrent nonfatal HF-related major adverse cardiac events as the primary efficacy end point without compromising the integrity of the statistical analyses for terminal cardiac events. In advanced chronic HF with reduced ejection fraction studies, the joint frailty model is utilized to reflect characteristics of the high-risk patient population with important unmet therapeutic needs. In some cases, use of the joint frailty model may substantially reduce sample size requirements. In addition, using an end point that is acceptable to the Food and Drug Administration and the European Medicines Agency, such as recurrent nonfatal HF-related major adverse cardiac events, enables generation of clinically relevant pharmacoeconomic data while providing comprehensive views of the patient's overall cardiovascular disease burden. The major goal of this review is to provide lessons learned from the ongoing DREAM-HF trial that relate to biologic plausibility and flexible clinical trial design and are potentially applicable to other development programs of innovative therapies for patients with advanced cardiovascular disease. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02032004.

A Path Forward for Regenerative Medicine.

Although clinical trials of cell-based approaches to cardiovascular disease have yielded some promising results, no cell-based therapy has achieved regulatory approval for a cardiovascular indication. To broadly assess the challenges to regulatory approval and identify strategies to facilitate this goal, the Cardiac Safety Research Consortium sponsored a session during the Texas Heart Institute International Symposium on Cardiovascular Regenerative Medicine in September 2017. This session convened leaders in cardiovascular regenerative medicine, including participants from academia, the pharmaceutical industry, the US Food and Drug Administration, and the Cardiac Safety Research Consortium, with particular focus on treatments closest to regulatory approval. A goal of the session was to identify barriers to regulatory approval and potential pathways to overcome them. Barriers identified include manufacturing and therapeutic complexity, difficulties identifying an optimal comparator group, limited industry capacity for funding pivotal clinical trials, and challenges to demonstrating efficacy on clinical end points required for regulatory decisions. Strategies to overcome these barriers include precompetitive development of a cell therapy registry network to enable dual-purposing of clinical data as part of pragmatic clinical trial design, development of standardized terminology for product activity and end points to facilitate this registry, use of innovative statistical methods and quality of life or functional end points to supplement outcomes such as death or heart failure hospitalization and reduce sample size, involvement of patients in determining the research agenda, and use of the Food and Drug Administration's new Regenerative Medicine Advanced Therapy designation to facilitate early discussion with regulatory authorities when planning development pathways.

TIME Trial: Effect of Timing of Stem Cell Delivery Following ST-Elevation Myocardial Infarction on the Recovery of Global and Regional Left Ventricular Function: Final 2-Year Analysis.

RATIONALE: The TIME trial (Timing in Myocardial Infarction Evaluation) was the first cell therapy trial sufficiently powered to determine if timing of cell delivery after ST-segment-elevation myocardial infarction affects recovery of left ventricular (LV) function. OBJECTIVE: To report the 2-year clinical and cardiac magnetic resonance imaging results and their modification by microvascular obstruction. METHODS AND RESULTS: TIME was a randomized, double-blind, placebo-controlled trial comparing 150 million bone marrow mononuclear cells versus placebo in 120 patients with anterior ST-segment-elevation myocardial infarctions resulting in LV dysfunction. Primary end points included changes in global (LV ejection fraction) and regional (infarct and border zone) function. Secondary end points included changes in LV volumes, infarct size, and major adverse cardiac events. Here, we analyzed the continued trajectory of these measures out to 2 years and the influence of microvascular obstruction present at baseline on these long-term outcomes. At 2 years (n=85), LV ejection fraction was similar in the bone marrow mononuclear cells (48.7%) and placebo groups (51.6%) with no difference in regional LV function. Infarct size and LV mass decreased ≥30% in each group at 6 months and declined gradually to 2 years. LV volumes increased ≈10% at 6 months and remained stable to 2 years. Microvascular obstruction was present in 48 patients at baseline and was associated with significantly larger infarct size (56.5 versus 36.2 g), greater adverse LV remodeling, and marked reduction in LV ejection fraction recovery (0.2% versus 6.2%). CONCLUSIONS: In one of the longest serial cardiac magnetic resonance imaging analyses of patients with large anterior ST-segment-elevation myocardial infarctions, bone marrow mononuclear cells administration did not improve recovery of LV function over 2 years. Microvascular obstruction was associated with reduced recovery of LV function, greater adverse LV remodeling, and more device implantations. The use of cardiac magnetic resonance imaging leads to greater dropout of patients over time because of device implantation in patients with more severe LV dysfunction resulting in overestimation of clinical stability of the cohort. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00684021.

Rationale and Design of the CONCERT-HF Trial (Combination of Mesenchymal and c-kit+ Cardiac Stem Cells As Regenerative Therapy for Heart Failure).

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: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02501811.

Evaluation of Cell Therapy on Exercise Performance and Limb Perfusion in Peripheral Artery Disease: The CCTRN PACE Trial (Patients With Intermittent Claudication Injected With ALDH Bright Cells).

BACKGROUND: Atherosclerotic peripheral artery disease affects 8% to 12% of Americans >65 years of age and is associated with a major decline in functional status, increased myocardial infarction and stroke rates, and increased risk of ischemic amputation. Current treatment strategies for claudication have limitations. PACE (Patients With Intermittent Claudication Injected With ALDH Bright Cells) is a National Heart, Lung, and Blood Institute-sponsored, randomized, double-blind, placebo-controlled, phase 2 exploratory clinical trial designed to assess the safety and efficacy of autologous bone marrow-derived aldehyde dehydrogenase bright (ALDHbr) cells in patients with peripheral artery disease and to explore associated claudication physiological mechanisms. METHODS: All participants, randomized 1:1 to receive ALDHbr cells or placebo, underwent bone marrow aspiration and isolation of ALDHbr cells, followed by 10 injections into the thigh and calf of the index leg. The coprimary end points were change from baseline to 6 months in peak walking time (PWT), collateral count, peak hyperemic popliteal flow, and capillary perfusion measured by magnetic resonance imaging, as well as safety. RESULTS: A total of 82 patients with claudication and infrainguinal peripheral artery disease were randomized at 9 sites, of whom 78 had analyzable data (57 male, 21 female patients; mean age, 66±9 years). The mean±SEM differences in the change over 6 months between study groups for PWT (0.9±0.8 minutes; 95% confidence interval [CI] -0.6 to 2.5; P=0.238), collateral count (0.9±0.6 arteries; 95% CI, -0.2 to 2.1; P=0.116), peak hyperemic popliteal flow (0.0±0.4 mL/s; 95% CI, -0.8 to 0.8; P=0.978), and capillary perfusion (-0.2±0.6%; 95% CI, -1.3 to 0.9; P=0.752) were not significant. In addition, there were no significant differences for the secondary end points, including quality-of-life measures. There were no adverse safety outcomes. Correlative relationships between magnetic resonance imaging measures and PWT were not significant. A post hoc exploratory analysis suggested that ALDHbr cell administration might be associated with an increase in the number of collateral arteries (1.5±0.7; 95% CI, 0.1-2.9; P=0.047) in participants with completely occluded femoral arteries. CONCLUSIONS: ALDHbr cell administration did not improve PWT or magnetic resonance outcomes, and the changes in PWT were not associated with the anatomic or physiological magnetic resonance imaging end points. Future peripheral artery disease cell therapy investigational trial design may be informed by new anatomic and perfusion insights. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01774097.

Rationale and Design of the SENECA (StEm cell iNjECtion in cAncer survivors) Trial.

OBJECTIVES: SENECA (StEm cell iNjECtion in cAncer survivors) is a phase I, randomized, double-blind, placebo-controlled study to evaluate the safety and feasibility of delivering allogeneic mesenchymal stromal cells (allo-MSCs) transendocardially in subjects with anthracycline-induced cardiomyopathy (AIC). BACKGROUND: AIC is an incurable and often fatal syndrome, with a prognosis worse than that of ischemic or nonischemic cardiomyopathy. Recently, cell therapy with MSCs has emerged as a promising new approach to repair damaged myocardium. METHODS: The study population is 36 cancer survivors with a diagnosis of AIC, left ventricular (LV) ejection fraction ≤40%, and symptoms of heart failure (NYHA class II-III) on optimally-tolerated medical therapy. Subjects must be clinically free of cancer for at least two years with a ≤ 30% estimated five-year risk of recurrence. The first six subjects participated in an open-label, lead-in phase and received 100 million allo-MSCs; the remaining 30 will be randomized 1:1 to receive allo-MSCs or vehicle via 20 transendocardial injections. Efficacy measures (obtained at baseline, 6 months, and 12 months) include MRI evaluation of LV function, LV volumes, fibrosis, and scar burden; assessment of exercise tolerance (six-minute walk test) and quality of life (Minnesota Living with Heart Failure Questionnaire); clinical outcomes (MACE and cumulative days alive and out of hospital); and biomarkers of heart failure (NT-proBNP). CONCLUSIONS: This is the first clinical trial using direct cardiac injection of cells for the treatment of AIC. If administration of allo-MSCs is found feasible and safe, SENECA will pave the way for larger phase II/III studies with therapeutic efficacy as the primary outcome.

Baseline assessment and comparison of arterial anatomy, hyperemic flow, and skeletal muscle perfusion in peripheral artery disease: The Cardiovascular Cell Therapy Research Network "Patients with Intermittent Claudication Injected with ALDH Bright Cells" (CCTRN PACE) study.

BACKGROUND: Peripheral artery disease (PAD) is important to public health as a major contributor to cardiovascular morbidity and mortality. Recent developments in magnetic resonance imaging (MRI) techniques permit improved assessment of PAD anatomy and physiology, and may serve as surrogate end points after proangiogenic therapies. METHODS: The PACE study is a randomized, double-blind, placebo-controlled clinical trial designed to assess the physiologic impact and potential clinical efficacy of autologous bone marrow-derived ALDHbr stem cells. The primary MRI end points of the study are as follows: (1) total collateral count, (2) calf muscle plasma volume (a measure of capillary perfusion) by dynamic contrast-enhanced MRI, and (3) peak hyperemic popliteal flow by phase-contrast MRI (PC-MRI). RESULTS: The interreader and intrareader and test-retest results demonstrated good-to-excellent reproducibility (interclass correlation coefficient range 0.61-0.98) for all magnetic resonance measures. The PAD participants (n=82) had lower capillary perfusion measured by calf muscle plasma volume (3.8% vs 5.6%) and peak hyperemic popliteal flow (4.1 vs 13.5mL/s) as compared with the healthy participants (n=16), with a significant level of collateralization. CONCLUSIONS: Reproducibility of the MRI primary end points in PACE was very good to excellent. The PAD participants exhibited decreased calf muscle capillary perfusion as well as arterial flow reserve when compared with healthy participants. The MRI tools used in PACE may advance PAD science by enabling accurate measurement of PAD microvascular anatomy and perfusion before and after stem cell or other PAD therapies.

Identification of cardiovascular risk factors associated with bone marrow cell subsets in patients with STEMI: a biorepository evaluation from the CCTRN TIME and LateTIME clinical trials.

Autologous bone marrow mononuclear cell (BM-MNC) therapy for patients with ST-segment elevation myocardial infarction (STEMI) has produced inconsistent results, possibly due to BM-MNC product heterogeneity. Patient-specific cardiovascular risk factors (CRFs) may contribute to variations in BM-MNC composition. We sought to identify associations between BM-MNC subset frequencies and specific CRFs in STEMI patients. Bone marrow was collected from 191 STEMI patients enrolled in the CCTRN TIME and LateTIME trials. Relationships between BM-MNC subsets and CRFs were determined with multivariate analyses. An assessment of CRFs showed that hyperlipidemia and hypertension were associated with a higher frequency of CD11b+ cells (P = 0.045 and P = 0.016, respectively). In addition, we found that females had lower frequencies of CD11b+ (P = 0.018) and CD45+CD14+ (P = 0.028) cells than males, age was inversely associated with the frequency of CD45+CD31+ cells (P = 0.001), smoking was associated with a decreased frequency of CD45+CD31+ cells (P = 0.013), glucose level was positively associated with the frequency of CD45+CD3+ cells, and creatinine level (an indicator of renal function) was inversely associated with the frequency of CD45+CD3+ cells (P = 0.015). In conclusion, the frequencies of monocytic, lymphocytic, and angiogenic BM-MNCs varied in relation to patients' CRFs. These phenotypic variations may affect cell therapy outcomes and might be an important consideration when selecting patients for and reviewing results from autologous cell therapy trials.

The Athena trials: Autologous adipose-derived regenerative cells for refractory chronic myocardial ischemia with left ventricular dysfunction.

OBJECTIVE: To assess safety and feasibility of autologous adipose-derived regenerative cells (ADRCs), for treatment of chronic ischemic cardiomyopathy patients. BACKGROUND: Preclinical and early clinical trials suggest ADRCs have excellent potential for ischemic conditions. METHODS: The Athena program consisted of two parallel, prospective, randomized (2:1, active: placebo), double-blind trials assessing intramyocardial (IM) ADRC delivery [40-million, n = 28 (ATHENA) and 80-million (ATHENA II) cells, n = 3]). Patients with an EF ≥20% but ≤45%, multivessel coronary artery disease (CAD) not amenable to revascularization, inducible ischemia, and symptoms of either angina (CCS II-IV) or heart failure (NYHA Class II-III) on maximal medical therapy were enrolled. All patients underwent fat harvest procedure (≤450 mL adipose), on-site cell processing (Celution® System, Cytori Therapeutics), electromechanical mapping, and IM delivery of ADRCs or placebo. RESULTS: Enrollment was terminated prematurely due to non-ADRC-related adverse events and subsequent prolonged enrollment time. Thirty-one patients (17-ADRCs, 14-placebo) mean age 65 ± 8 years, baseline LVEF(%) 31.1 ± 8.7 (ADRC), 31.8 ± 7.7 (placebo) were enrolled. Change in V02 max favored ADRCs (+45.4 ± 222 vs. -9.5 ± 137 mL/min) but there was no difference in left ventricular function or volumes. At 12-months, heart failure hospitalizations occurred in 2/17 (11.7%) [ADRC] and 3/14 (21.4%) [placebo]. Differences in NYHA and CCS classes favored ADRCs at 12-months with significant improvement in MLHFQ (-21.6 + 13.9 vs. -5.5 + 23.8, P = 0.038). CONCLUSIONS: A small volume fat harvest, automated local processing, and IM delivery of autologous ADRCs is feasible with suggestion of benefit in "no option" CAD patients. Although the sample size is limited, the findings support feasibility and scalability for treatment of ischemic cardiomyopathy with ADRCs. © 2016 Wiley Periodicals, Inc.

A Phase II Dose-Escalation Study of Allogeneic Mesenchymal Precursor Cells in Patients With Ischemic or Nonischemic Heart Failure.

RATIONALE: Allogeneic mesenchymal precursor cells (MPCs) have been effective in large animal models of ischemic and nonischemic heart failure (HF). OBJECTIVE: To evaluate the feasibility and safety of 3 doses (25, 75, or 150 million cells) of immunoselected allogeneic MPCs in chronic HF patients in a phase 2 trial. METHODS AND RESULTS: We sequentially allocated 60 patients to a dosing cohort (20 per dose group) and randomized them to transendocardial MPC injections (n=15) or mock procedures (n=5). The primary objective was safety, including antibody testing. Secondary efficacy end points included major adverse cardiac events (MACE; cardiac death, myocardial infarction, or revascularization), left ventricular imaging, and other clinical-event surrogates. Safety and MACE were evaluated for up to 3 years. MPC injections were feasible and safe. Adverse events were similar across groups. No clinically symptomatic immune responses were noted. MACE was seen in 15 patients: 10 of 45 (22%) MPC-treated and 5 of 15 (33%) control patients. We found no differences between MPC-treated and control patients in survival probability, MACE-free probability, and all-cause mortality. We conducted a post hoc analysis of HF-related MACE (HF hospitalization, successfully resuscitated cardiac death, or cardiac death) and events were significantly reduced in the 150 million MPC group (0/15) versus control (5/15; 33%), 25 million MPC group (3/15; 20%), and 75 million MPC group (6/15; 40%); the 150 million MPC group differed significantly from all groups according to Kaplan-Meier statistics >3 years (P=0.025 for 150 million MPC group versus control). CONCLUSIONS: Transendocardial injections of allogeneic MPCs were feasible and safe in chronic HF patients. High-dose allogeneic MPCs may provide benefits in this population.

Bone marrow characteristics associated with changes in infarct size after STEMI: a biorepository evaluation from the CCTRN TIME trial.

RATIONALE: Despite significant interest in bone marrow mononuclear cell (BMC) therapy for ischemic heart disease, current techniques have resulted in only modest benefits. However, selected patients have shown improvements after autologous BMC therapy, but the contributing factors are unclear. OBJECTIVE: The purpose of this study was to identify BMC characteristics associated with a reduction in infarct size after ST-segment-elevation-myocardial infarction. METHODS AND RESULTS: This prospective study comprised patients consecutively enrolled in the CCTRN TIME (Cardiovascular Cell Therapy Research Network Timing in Myocardial Infarction Evaluation) trial who agreed to have their BMCs stored and analyzed at the CCTRN Biorepository. Change in infarct size between baseline (3 days after percutaneous coronary intervention) and 6-month follow-up was measured by cardiac MRI. Infarct-size measurements and BMC phenotype and function data were obtained for 101 patients (mean age, 56.5 years; mean screening ejection fraction, 37%; mean baseline cardiac MRI ejection fraction, 45%). At 6 months, 75 patients (74.3%) showed a reduction in infarct size (mean change, -21.0±17.6%). Multiple regression analysis indicated that infarct size reduction was greater in patients who had a larger percentage of CD31(+) BMCs (P=0.046) and in those with faster BMC growth rates in colony-forming unit Hill and endothelial-colony forming cell functional assays (P=0.033 and P=0.032, respectively). CONCLUSIONS: This study identified BMC characteristics associated with a better clinical outcome in patients with segment-elevation-myocardial infarction and highlighted the importance of endothelial precursor activity in regenerating infarcted myocardium. Furthermore, it suggests that for these patients with segment-elevation-myocardial infarction, myocardial repair was more dependent on baseline BMC characteristics than on whether the patient underwent intracoronary BMC transplantation. CLINICAL TRIAL REGISTRATION INFORMATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00684021.

Bone marrow cell characteristics associated with patient profile and cardiac performance outcomes in the LateTIME-Cardiovascular Cell Therapy Research Network (CCTRN) trial.

BACKGROUND: Although several preclinical studies have shown that bone marrow cell (BMC) transplantation promotes cardiac recovery after myocardial infarction, clinical trials with unfractionated bone marrow have shown variable improvements in cardiac function. METHODS: To determine whether in a population of post-myocardial infarction patients, functional recovery after BM transplant is associated with specific BMC subpopulation, we examined the association between BMCs with left ventricular (LV) function in the LateTIME-CCTRN trial. RESULTS: In this population, we found that older individuals had higher numbers of BM CD133(+) and CD3(+) cells. Bone marrow from individuals with high body mass index had lower CD45(dim)/CD11b(dim) levels, whereas those with hypertension and higher C-reactive protein levels had higher numbers of CD133(+) cells. Smoking was associated with higher levels of CD133(+)/CD34(+)/VEGFR2(+) cells and lower levels of CD3(+) cells. Adjusted multivariate analysis indicated that CD11b(dim) cells were negatively associated with changes in LV ejection fraction and wall motion in both the infarct and border zones. Change in LV ejection fraction was positively associated with CD133(+), CD34(+), and CD45(+)/CXCR4(dim) cells as well as faster BMC growth rates in endothelial colony forming assays. CONCLUSIONS: In the LateTIME population, BM composition varied with patient characteristics and treatment. Irrespective of cell therapy, recovery of LV function was greater in patients with greater BM abundance of CD133(+) and CD34(+) cells and worse in those with higher levels of CD11b(dim) cells. Bone marrow phenotype might predict clinical response before BMC therapy and administration of selected BM constituents could potentially improve outcomes of other future clinical trials.

Detailed analysis of bone marrow from patients with ischemic heart disease and left ventricular dysfunction: BM CD34, CD11b, and clonogenic capacity as biomarkers for clinical outcomes.

RATIONALE: Bone marrow (BM) cell therapy for ischemic heart disease (IHD) has shown mixed results. Before the full potency of BM cell therapy can be realized, it is essential to understand the BM niche after acute myocardial infarction (AMI). OBJECTIVE: To study the BM composition in patients with IHD and severe left ventricular (LV) dysfunction. METHODS AND RESULTS: BM from 280 patients with IHD and LV dysfunction were analyzed for cell subsets by flow cytometry and colony assays. BM CD34(+) cell percentage was decreased 7 days after AMI (mean of 1.9% versus 2.3%-2.7% in other cohorts; P<0.05). BM-derived endothelial colonies were significantly decreased (P<0.05). Increased BM CD11b(+) cells associated with worse LV ejection fraction (LVEF) after AMI (P<0.05). Increased BM CD34(+) percentage associated with greater improvement in LVEF (+9.9% versus +2.3%; P=0.03, for patients with AMI and +6.6% versus -0.02%; P=0.021 for patients with chronic IHD). In addition, decreased BM CD34(+) percentage in patients with chronic IHD correlated with decrement in LVEF (-2.9% versus +0.7%; P=0.0355). CONCLUSIONS: In this study, we show a heterogeneous mixture of BM cell subsets, decreased endothelial colony capacity, a CD34+ cell nadir 7 days after AMI, a negative correlation between CD11b percentage and postinfarct LVEF, and positive correlation of CD34 percentage with change in LVEF after cell therapy. These results serve as a possible basis for the small clinical improvement seen in autologous BM cell therapy trials and support selection of potent cell subsets and reversal of comorbid BM impairment. CLINICAL TRIAL REGISTRATIONS URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00684021, NCT00684060, and NCT00824005.

Transplantation of mesenchymal cells rejuvenated by the overexpression of telomerase and myocardin promotes revascularization and tissue repair in a murine model of hindlimb ischemia.

RATIONALE: The number and function of stem cells decline with aging, reducing the ability of stem cells to contribute to endogenous repair processes. The repair capacity of stem cells in older individuals may be improved by genetically reprogramming the stem cells to exhibit delayed senescence and enhanced regenerative properties. OBJECTIVE: We examined whether the overexpression of myocardin (MYOCD) and telomerase reverse transcriptase (TERT) enhanced the survival, growth, and myogenic differentiation of mesenchymal stromal cells (MSCs) isolated from adipose or bone marrow tissues of aged mice. We also examined the therapeutic efficacy of transplanted MSCs overexpressing MYOCD and TERT in a murine model of hindlimb ischemia. METHODS AND RESULTS: MSCs from adipose or bone marrow tissues of young (1 month old) and aged (12 months old) male C57BL/6 and apolipoprotein E-null mice were transiently transduced with lentiviral vectors encoding TERT, MYOCD, or both TERT and MYOCD. Flow cytometry and bromodeoxyuridine cell proliferation assays showed that transduction with TERT and, to a lesser extent, MYOCD, increased MSC viability and proliferation. In colony-forming assays, MSCs overexpressing TERT and MYOCD were more clonogenic than mock-transduced MSCs. Fas-induced apoptosis was inhibited in MSCs overexpressing MYOCD or TERT. When compared with aged mock-transduced MSCs, aged MSCs overexpressing TERT, MYOCD, or both TERT and MYOCD increased myogenic marker expression, blood flow, and arteriogenesis when transplanted into the ischemic hindlimbs of apolipoprotein E-null mice. CONCLUSIONS: The delivery of the TERT and MYOCD genes into MSCs may have therapeutic applications for restoring, or rejuvenating, aged MSCs from adipose and bone marrow tissues.

Rationale and design for PACE: patients with intermittent claudication injected with ALDH bright cells.

Peripheral artery disease (PAD) is recognized as a public health issue because of its prevalence, functional limitations, and increased risk of systemic ischemic events. Current treatments for claudication, the primary symptom in patients with PAD, have limitations. Cells identified using cytosolic enzyme aldehyde dehydrogenase (ALDH) may benefit patients with severe PAD but has not been studied in patients with claudication. PACE is a randomized, double-blind, placebo-controlled clinical trial conducted by the Cardiovascular Cell Therapy Research Network to assess the safety and efficacy of autologous bone marrow-derived ALDH(br) cells delivered by direct intramuscular injections in 80 patients with symptom-limiting intermittent claudication. Eligible patients will have a significant stenosis or occlusion of infrainguinal arteries and a resting ankle-brachial index less than 0.90 and will be randomized 1:1 to cell or placebo treatment with a 1-year follow-up. The primary end points are the change in peak walking time and leg collateral arterial anatomy, calf muscle blood flow, and tissue perfusion as determined by magnetic resonance imaging at 6 months compared with baseline. The latter 3 measurements are new physiologic lower extremity tissue perfusion and PAD imaging-based end points that may help to quantify the biologic and mechanistic effects of cell therapy. This trial will collect important mechanistic and clinical information on the safety and efficacy of ALDH(br) cells in patients with claudication and provide valuable insight into the utility of advanced magnetic resonance imaging end points.

Adipose-derived regenerative cells in patients with ischemic cardiomyopathy: The PRECISE Trial.

AIMS: Adipose-derived regenerative cells (ADRCs) can be isolated from liposuction aspirates and prepared as fresh cells for immediate administration in cell therapy. We performed the first randomized, placebo-controlled, double-blind trial to examine the safety and feasibility of the transendocardial injections of ADRCs in no-option patients with ischemic cardiomyopathy. METHODS AND RESULTS: Procedural, postoperative, and follow-up safety end points were monitored up to 36 months. After baseline measurements, efficacy was assessed by echocardiography and single-photon emission computed tomography (6, 12, and 18 months), metabolic equivalents and maximal oxygen consumption (MVO2) (6 and 18 months), and cardiac magnetic resonance imaging (6 months). We enrolled 21 ADRC-treated and 6 control patients. Liposuction was well tolerated, ADRCs were successfully prepared, and transendocardial injections were feasible in all patients. No malignant arrhythmias were seen. Adverse events were similar between groups. Metabolic equivalents and MVO2 values were preserved over time in ADRC-treated patients but declined significantly in the control group. The difference in the change in MVO2 from baseline to 6 and 18 months was significantly better in ADRC-treated patients compared with controls. The ADRC-treated patients showed significant improvements in total left ventricular mass by magnetic resonance imaging and wall motion score index. Single-photon emission computed tomography results suggested a reduction in inducible ischemia in ADRC-treated patients up to 18 months. CONCLUSION: Isolation and transendocardial injection of autologous ADRCs in no-option patients were safe and feasible. Our results suggest that ADRCs may preserve ventricular function, myocardial perfusion, and exercise capacity in these patients.

A critical analysis of clinical outcomes reported in stem cell trials for acute myocardial infarction: some thoughts for design of future trials.

The purpose of stem cell therapy for myocardial infarction is to improve clinical outcomes, and detailed information on clinical outcomes is critical to appropriate planning of phase III trials. We have examined data from select phase II trials using autologous bone-marrow-derived stem cells in patients with acute myocardial infarction. We have extracted available definitions and outcome data, and have generated standardized estimates of events to permit summary comparisons. Nine trials (1,040 patients) with results for 6 months to 5 years were evaluated. Adverse outcomes differed widely, and there was a general lack of details in the definitions of these outcomes. Heart-failure-related hospitalizations occurred in only 16 patients (1.5 %) and death occurred in only 43 patients (4.1 %). Ischemia-related outcomes outnumbered heart failure outcomes more than tenfold. Uniform criteria need to be developed to better define clinical outcomes of interest. Furthermore, a refocus from heart failure outcomes to ischemia-related outcomes seems appropriate.