Transendocardial mesenchymal stem cells and mononuclear bone marrow cells for ischemic cardiomyopathy: the TAC-HFT randomized trial

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). The study compared injection of MSCs (n=19) with placebo (n = 11) and BMCs (n = 19) with placebo (n = 10), with 1 year of follow-up.

INTERVENTIONS

Injections in 10 LV sites with an infusion catheter.

MAIN OUTCOMES AND MEASURES

Treatment-emergent 30-day serious adverse event rate defined as a composite of death, myocardial infarction, stroke, hospitalization for worsening heart failure, perforation, tamponade, or sustained ventricular arrhythmias.

RESULTS

No patient had a treatment-emergent serious adverse events at day 30. The 1-year incidence of serious adverse events was 31.6% (95% CI, 12.6% to 56.6%) for MSCs, 31.6% (95% CI, 12.6%-56.6%) for BMCs, and 38.1% (95% CI, 18.1%-61.6%) for placebo. Over 1 year, the Minnesota Living With Heart Failure score improved with MSCs (-6.3; 95% CI, -15.0 to 2.4; repeated measures of variance, P=.02) and with BMCs (-8.2; 95% CI, -17.4 to 0.97; P=.005) but not with placebo (0.4; 95% CI, -9.45 to 10.25; P=.38). The 6-minute walk distance increased with MSCs only (repeated measures model, P = .03). Infarct size as a percentage of LV mass was reduced by MSCs (-18.9%; 95% CI, -30.4 to -7.4; within-group, P = .004) but not by BMCs (-7.0%; 95% CI, -15.7% to 1.7%; within-group, P = .11) or placebo (-5.2%; 95% CI, -16.8% to 6.5%; within-group, P = .36). Regional myocardial function as peak Eulerian circumferential strain at the site of injection improved with MSCs (-4.9; 95% CI, -13.3 to 3.5; within-group repeated measures, P = .03) but not BMCs (-2.1; 95% CI, -5.5 to 1.3; P = .21) or placebo (-0.03; 95% CI, -1.9 to 1.9; P = .14). Left ventricular chamber volume and ejection fraction did not change.

CONCLUSIONS AND RELEVANCE

Transendocardial stem cell injection with MSCs or BMCs appeared to be safe for patients with chronic ischemic cardiomyopathy and LV dysfunction. Although the sample size and multiple comparisons preclude a definitive statement about safety and clinical effect, these results provide the basis for larger studies to provide definitive evidence about safety and to assess efficacy of this new therapeutic approach.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00768066.

Durable scar size reduction due to allogeneic mesenchymal stem cell therapy regulates whole-chamber remodeling

BACKGROUND

Intramyocardial injection of mesenchymal stem cells (MSCs) in chronic ischemic cardiomyopathy is associated with reverse remodeling in experimental models and humans. Here, we tested the hypothesis that allogeneic MSC therapy drives ventricular remodeling by producing durable and progressive scar size reduction in ischemic cardiomyopathy.

METHODS AND RESULTS

Gottingen swine (n=12) underwent left anterior descending coronary artery myocardial infarction (MI), and 3 months post-MI animals received either intramyocardial allogeneic MSC injection (200 mol/L cells; n=6) or left ventricle (LV) catheterization without injection (n=6). Swine were followed with serial cardiac magnetic resonance imaging for 9 months to assess structural and functional changes of the LV. Intramyocardial injection was performed using an integrated imaging platform combining electroanatomical mapping unipolar voltage and 3-dimensional cardiac magnetic resonance imaging angiography-derived anatomy to accurately target infarct border zone injections. MSC-treated animals had a 19.62 ± 2.86% reduction in scar size at 3 months postinjection, which progressed to 28.09 ± 2.31% from 3 to 6 months postinjection (P<0.0001). MSC-treated animals had unchanged end-diastolic volume (EDV; P=0.08) and end-systolic volume (ESV; P=0.28) from preinjection to 6 months postinjection, whereas controls had progressive dilatation in both EDV (P=0.0002) and ESV (P=0.0002). In addition, MSC-treated animals had improved LV sphericity index. Percentage change in infarct size correlated with percentage change in EDV (r=0.68; P=0.01) and ESV (r=0.77; P=0.001). Ejection fraction increased from 29.69 ± 1.68% to 35.85 ± 2.74% at 3 months post-MSC injection and progressed to 39.02 ± 2.42% 6 months postinjection (P=0.0001), whereas controls had a persistently depressed ejection fraction during follow-up (P=0.33).

CONCLUSION

Intramyocardial injection of allogeneic MSCs leads to a sustained and progressive reduction in infarct size, which in turn drives reverse remodeling and increases in ejection fraction. These findings support ongoing biological activity of cell therapy for substantial periods and suggest optimal end points for future clinical trials.

Comparison of allogeneic vs autologous bone marrow–derived mesenchymal stem cells delivered by transendocardial injection in patients with ischemic cardiomyopathy: the POSEIDON randomized trial

CONTEXT

Mesenchymal stem cells (MSCs) are under evaluation as a therapy for ischemic cardiomyopathy (ICM). Both autologous and allogeneic MSC therapies are possible; however, their safety and efficacy have not been compared.

OBJECTIVE

To test whether allogeneic MSCs are as safe and effective as autologous MSCs in patients with left ventricular (LV) dysfunction due to ICM.

DESIGN, SETTING, AND PATIENTS

A phase 1/2 randomized comparison (POSEIDON study) in a US tertiary-care referral hospital of allogeneic and autologous MSCs in 30 patients with LV dysfunction due to ICM between April 2, 2010, and September 14, 2011, with 13-month follow-up.

INTERVENTION

Twenty million, 100 million, or 200 million cells (5 patients in each cell type per dose level) were delivered by transendocardial stem cell injection into 10 LV sites.

MAIN OUTCOME MEASURES

Thirty-day postcatheterization incidence of predefined treatment-emergent serious adverse events (SAEs). Efficacy assessments included 6-minute walk test, exercise peak VO2, Minnesota Living with Heart Failure Questionnaire (MLHFQ), New York Heart Association class, LV volumes, ejection fraction (EF), early enhancement defect (EED; infarct size), and sphericity index.

RESULTS

Within 30 days, 1 patient in each group (treatment-emergent SAE rate, 6.7%) was hospitalized for heart failure, less than the prespecified stopping event rate of 25%. The 1-year incidence of SAEs was 33.3% (n = 5) in the allogeneic group and 53.3% (n = 8) in the autologous group (P = .46). At 1 year, there were no ventricular arrhythmia SAEs observed among allogeneic recipients compared with 4 patients (26.7%) in the autologous group (P = .10). Relative to baseline, autologous but not allogeneic MSC therapy was associated with an improvement in the 6-minute walk test and the MLHFQ score, but neither improved exercise VO2 max. Allogeneic and autologous MSCs reduced mean EED by −33.21% (95% CI, −43.61% to −22.81%; P < .001) and sphericity index but did not increase EF. Allogeneic MSCs reduced LV end-diastolic volumes. Low-dose concentration MSCs (20 million cells) produced greatest reductions in LV volumes and increased EF. Allogeneic MSCs did not stimulate significant donor-specific alloimmune reactions.

CONCLUSIONS

In this early-stage study of patients with ICM, transendocardial injection of allogeneic and autologous MSCs without a placebo control were both associated with low rates of treatment-emergent SAEs, including immunologic reactions. In aggregate, MSC injection favorably affected patient functional capacity, quality of life, and ventricular remodeling.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01087996.

Abstract 246: Transendocardial Injections of Allogeneic Mesenchymal Stem Cells Demonstrate Reversal of Left Ventricular Remodeling to Baseline

Background: Mesenchymal stem cells (MSCs) improve ventricular function post MI

Hypothesis: Transendocardial stem cell injections (TESI) reverse remodeling in a swine model of chronic ischemic cardiomyopathy (CIC).

Methods: Gottingen swine (n=12), underwent a closed-chest, LAD occlusion-reperfusion model to create chronic ischemic cardiomyopathy. Three months post-MI, transendocardial injections of allogeneic MSCs (n=6) or sham injection (control group, n=6) were administered to the infarct and border zones. Cardiac MRI and pressure volume loops were obtained at baseline, during injection, and 6 months post injection. The three dimensional sphericity index (SI) was determined using the formula, SI= (π x LVLA3)/6, where LVLA is the left ventricle long axis length as measured in a 4-chamber long axis cardiac MRI end diastolic frame perpendicular to the line from the annulus of the mitral valve to the apex.

Results: The sphericity index increased in both groups 3 months after MI, from 0.268 ± 0.054 to 0.348 ± 0.050 in the sham injection group and 0.277 ± 0.051 to 0.380 ± 0.059 in the TESI group. In the sham injection group, SI remained stable 9 months post sham injections indicative of irreversible remodeling post MI. In contrast, the injection group SI continued to decrease from 0.380 ± 0.059 to 0.346 ± 0.064 and 0.280 ± 0.50 at 3 and 6 months post TESI, respectively.

Conclusions: Measurements of SI show that transendocardial stem cell injections of allogeneic MSCs demonstrate the potential to reverse left ventricular remodeling in CIC patients to geometric configurations comparable to their pre-MI shapes.

Intramyocardial stem cell injection in patients with ischemic cardiomyopathy: functional recovery and reverse remodeling

RATIONALE

Transcatheter, intramyocardial injections of bone marrow-derived cell therapy produces reverse remodeling in large animal models of ischemic cardiomyopathy.

OBJECTIVE

We used cardiac MRI (CMR) in patients with left ventricular (LV) dysfunction related to remote myocardial infarction (MI) to test the hypothesis that bone marrow progenitor cell injection causes functional recovery of scarred myocardium and reverse remodeling.

METHODS AND RESULTS

Eight patients (aged 57.2±13.3 years) 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 versus 167.4±7.32 mL; P=0.03), a trend toward decreased end systolic volume (142.4±16.5 versus 107.6±7.4 mL; P=0.06), decreased infarct size (P<0.05), and improved regional LV function by peak Eulerian circumferential strain in the treated infarct zone (-8.1±1.0 versus -11.4±1.3; P=0.04). Improvements in regional function were evident at 3 months, whereas the changes in chamber dimensions were not significant until 6 months. Improved regional function in the infarct zone strongly correlated with reduction of end diastolic volume (r(2)=0.69, P=0.04) and end systolic volume (r(2)=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.

Bone marrow mesenchymal stem cells stimulate cardiac stem cell proliferation and differentiation

RATIONALE

The regenerative potential of the heart is insufficient to fully restore functioning myocardium after injury, motivating the quest for a cell-based replacement strategy. Bone marrow-derived mesenchymal stem cells (MSCs) have the capacity for cardiac repair that appears to exceed their capacity for differentiation into cardiac myocytes.

OBJECTIVE

Here, we test the hypothesis that bone marrow derived MSCs stimulate the proliferation and differentiation of endogenous cardiac stem cells (CSCs) as part of their regenerative repertoire.

METHODS AND RESULTS

Female Yorkshire pigs (n=31) underwent experimental myocardial infarction (MI), and 3 days later, received transendocardial injections of allogeneic male bone marrow-derived MSCs, MSC concentrated conditioned medium (CCM), or placebo (Plasmalyte). A no-injection control group was also studied. MSCs engrafted and differentiated into cardiomyocytes and vascular structures. In addition, endogenous c-kit(+) CSCs increased 20-fold in MSC-treated animals versus controls (P<0.001), there was a 6-fold increase in GATA-4(+) CSCs in MSC versus control (P<0.001), and mitotic myocytes increased 4-fold (P=0.005). Porcine endomyocardial biopsies were harvested and plated as organotypic cultures in the presence or absence of MSC feeder layers. In vitro, MSCs stimulated c-kit(+) CSCs proliferation into enriched populations of adult cardioblasts that expressed Nkx2-5 and troponin I.

CONCLUSIONS

MSCs stimulate host CSCs, a new mechanism of action underlying successful cell-based therapeutics.

Evaluation of comorbidity scores to predict all-cause mortality in patients with established coronary artery disease

BACKGROUND

To assess the value of scores based on the presence of comorbid conditions for mortality risk-stratification in patients with coronary artery disease (CAD) METHODS: We prospectively followed 305 males with CAD undergoing coronary angiography for 58 months. We correlated the modified Charlson Index (MCI) and the recently proposed CAD-specific index (CSI) with the risk of all-cause mortality.

RESULTS

The odds ratio (OR) for death increased by 31% per point increase in the MCI (95% CI=17-46%; p<0.0001). The OR for death increased by 16% per point increase in the CSI (95% CI=8.5-25%; p<0.0001). In logistic regression models that adjusted for age, left ventricular ejection fraction, and the number of vessels involved with CAD, both the MCI and the CSI were the strongest predictors of mortality according to the chi2 value for each term, with the MCI having the highest value. The adjusted OR per point increase in the MCI was 1.32 (95% CI=1.17-1.48; p<0.0001); the corresponding adjusted OR per point increase in the CSI was 1.17 (95% CI=1.09-1.26; p<0.0001). The model including the MCI had a slightly higher chi2 value (45.1 vs. 39.1) and area under the receiver operator characteristic curve (0.742 vs. 0.727) than the model including the CSI.

CONCLUSION

The MCI and the newly proposed CSI are powerful tools to predict all-cause mortality in patients with established CAD. Although the CSI was not superior to the MCI, its simplicity might make it useful in populations with a low prevalence of comorbidities not included in this score.

Is TEE useful in patients with small subcortical strokes?

Although the role of transesophageal echocardiography (TEE) in the investigation of stroke mechanism is well established, the value of this test in patients with lacunar presentation is unclear. Review of 214 patients with acute cerebral ischemia referred for TEE to exclude cardioaortic sources of embolism after non-diagnostic basic work-up including carotid ultrasound and transthoracic echocardiography. TEE was considered positive when it showed large or complex aortic arch plaques, left atrial thrombus, mitral or aortic valve vegetations, or patent foramen ovale with atrial septal aneurysm. Multivariate regression analysis was performed to assess the value of lacunar syndrome and radiological small subcortical infarctions in predicting TEE result. Predictive values and likelihood ratios for these variables were calculated. Fifty-two patients (24%) had positive TEE. The most common embolic source was large or complex aortic plaques in 19% of patients. Neither clinical presentation with lacunar syndrome nor the presence of small subcortical infarction on CT scan predicted a negative TEE result on univariate or multivariate analysis. However, the combination of lacunar syndrome with radiological small subcortical infarction was uniformly associated with negative TEE (P=0.01; negative predictive value 100%). The combination of lacunar syndrome with small subcortical radiological infarct predicts the absence of cardioaortic sources of embolism on TEE in patients with acute cerebral ischemia.

Ability of serum to decrease cellular acylCoA:cholesterol acyl transferase activity predicts cardiovascular outcomes

BACKGROUND

We evaluated whether cholesterol efflux activity of serum is associated with the presence of angiographic coronary artery disease (CAD) and the risk of major adverse cardiovascular events (MACE) and death.

METHODS AND RESULTS

We studied 168 men undergoing coronary angiography. Cholesterol efflux activity was measured in vitro by incubation of patient serum with human skin fibroblasts and defined as the ability of serum to decrease the pool of cholesterol available for esterification by the acylCoA:cholesterol acyl transferase (ACAT) reaction. We evaluated whether this activity was associated with the presence of CAD and the risk of MACE and death during a 4.5-year follow-up. Serum-induced changes in ACAT activity did not correlate with HDL levels or the presence of CAD. Patients in the highest tertile of change in ACAT activity had a significantly higher risk for MACE (HR, 2.15; 95% CI, 1.36 to 3.39; P=0.001) and death (HR, 2.23; 95% CI, 1.17 to 4.26; P=0.01). These correlations were independent of other risk markers including LDL, HDL, and C-reactive protein levels.

CONCLUSIONS

Serum-induced depletion of cellular cholesterol available for esterification by ACAT was a strong, independent predictor of MACE and death. We speculate that the ability of serum to decrease ACAT activity depends on ATP binding cassette transporter A1 (ABCA1)-mediated efflux. Furthermore, serum samples that induce larger changes in ACAT activity contain increased levels of HDL particles that preferentially interact with ABCA1 and that these particles accumulate in the serum of patients because of low activity of ABCA1 in vivo preventing or limiting the extent of apoA-I lipidation.

Relation between ascending aortic pressures and outcomes in patients with angiographically demonstrated coronary artery disease

We prospectively followed 324 men, who underwent coronary angiography, for 1,161 +/- 418 days. We analyzed the association between ascending aortic pressures measured during cardiac catheterization and the risk of all-cause mortality and a combined end point of major adverse cardiovascular events (MACEs), including unstable angina pectoris, myocardial infarction, coronary revascularization, stroke, or death. Pulse pressure significantly predicted MACEs (hazard ratio [HR] per 10 mm Hg increase 1.09, 95% confidence interval [CI] 1.002 to 1.17, p = 0.04). Diastolic blood pressure (BP) inversely correlated with the risk of MACEs (HR per 10 mm Hg increase 0.85, 95% CI 0.74 to 0.98, p = 0.02). These correlations remained significant after adjusting for other predictors and potential confounders. The association between lower diastolic BP with the risk of MACEs was more pronounced in patients with triple-vessel coronary artery disease (p for interaction = 0.03). Peripheral diastolic BP (but not pulse pressure) correlated inversely with the risk of MACEs (HR 0.87 per 10 mm Hg increase, 95% CI 0.75 to 0.998, p = 0.047). Aortic pulse pressure significantly predicted death (HR per 10 mm Hg increase 1.18, 95% CI 1.05 to 1.33, p = 0.004), and aortic diastolic BP correlated inversely with the risk of death (HR 0.76, 95% CI 0.62 to 0.94, p = 0.01).

Elevation of endothelial microparticles, platelets, and leukocyte activation in patients with venous thromboembolism

OBJECTIVES

The purpose of this research was to determine the levels of platelet, leukocyte, and endothelial activation and markers of cellular interactions in patients with venous thromboembolism (VTE).

BACKGROUND

The details of interactions between endothelium, platelets, and leukocytes in VTE are not well understood.

METHODS

We studied 25 patients with VTE and compared 25 healthy controls. We used flow cytometry to measure: 1) endothelial microparticles (EMP) identified by CD31+/CD42b- (EMP(31)) or E-selectin (EMP(62E)); 2) platelet microparticles (CD31+/CD42b+); 3) surface expression of P-selectin in platelets and CD11b in leukocytes; 4) EMP-monocyte conjugates (percentage of monocytes positive for E-selectin); and 5) platelet-leukocyte conjugates (PLC) expressed as percentage of leukocytes positive for CD41.

RESULTS

Patients with VTE had marked elevations of EMP(31) (2,193 vs. 383 counts/microl; p = 0.003), EMP(62E) (368 vs. 223 counts/microl; p = 0.001), and EMP-monocyte conjugates (3.3% vs. 2.5%; p = 0.002), as well as increased activation of platelets (35.2 vs. 5.0 fluorescence intensity units for P-selectin; p < 0.0001) and leukocytes (13.9 vs. 7.7 U for CD11b; p = 0.004). Also elevated in VTE were PLC (61.7% vs. 39.6%; p = 0.01). Expression of CD11b in leukocytes strongly correlated with PLC (r = 0.74; p < 0.0001).

CONCLUSIONS

Marked activation of endothelium, platelets, and leukocytes occurs in VTE, and VTE, or the accompanying inflammatory process, involves the release of EMP and formation of EMP-monocyte conjugates and PLC. These findings support prior studies suggesting that release of EMP and their binding to monocytes are key events in thrombogenesis. Our findings also support the concept that the formation of PLC regulates leukocyte activation and participates in linking thrombosis with inflammation.

Aortic pressure augmentation predicts adverse cardiovascular events in patients with established coronary artery disease

Pulse pressure (PP), a marker of arterial stiffness, predicts cardiovascular risk. We aimed to determine whether augmentation pressure (AP) derived from the aortic pressure waveform predicts major adverse cardiovascular events (MACE) and death independently of PP in patients with established coronary artery disease (CAD). We prospectively followed-up 297 males undergoing coronary angiography for 1186+/-424 days. Ascending aortic pressure tracings obtained during catheterization were used to calculate AP (difference between the second and the first systolic peak). Augmentation index (AIx) was defined as AP as a percentage of PP. We evaluated whether AP and AIx can predict the risk of MACE (unstable angina, acute myocardial infarction, coronary revascularization, stroke, or death) and death using Cox regression. All models evaluating AP included PP to assess whether AP adds to the information already provided by PP. Both AP and AIx significantly predicted MACE. The hazard ratio (HR) per 10 mm Hg increase in AP was 1.20 (95% confidence interval [CI], 1.08 to 1.34; P<0.001); the HR for each 10% increase in AIx was 1.28 (95% CI, 1.11 to 1.48; P=0.004). After adjusting for other univariate predictors of MACE, age, and other potential confounders, AP remained a significant predictor of MACE (HR per 10 mm Hg increase=1.19; 95% CI, 1.06 to 1.34; P=0.002), as did AIx (adjusted HR, 1.28; 95% CI, 1.09 to 1.50; P=0.003). AP was a significant predictor of death (HR per 10 mm Hg increase=1.18; 95% CI, 1.02 to 1.39; P=0.03). Higher AIx was associated with a trend toward increased mortality (HR=1.22; 95% CI, 0.98 to 1.52; P=0.056). Aortic AP predicts adverse outcomes in patients with CAD independently of PP and other risk markers.

Usefulness of C-reactive protein as an independent predictor of death in patients with ischemic cardiomyopathy

The usefulness of serum C-reactive protein, an inflammatory marker, to predict mortality risk in patients who have ischemic cardiomyopathy was investigated. C-reactive protein was measured in 123 men who underwent cardiac catheterization and were noted to have left ventricular ejection fraction <or=45% and significant angiographic coronary artery disease. They were prospectively followed for 3 years. Higher levels of C-reactive protein were associated with increased mortality rate. This correlation was independent of other prognostic factors, such as age, ejection fraction, symptoms of severe congestive heart failure, use of angiotensin-converting enzyme inhibitors, and use of beta blockers.

Noncompaction of the ventricular myocardium: the use of contrast-enhanced echocardiography in diagnosis

We describe a case of noncompaction of the ventricular myocardium diagnosed in the preoperative evaluation of a patient undergoing renal transplantation. Ventricular noncompaction is characterized by numerous prominent trabecular recesses with intratrabecular blood from the ventricular cavity. Color Doppler was suggestive of intramyocardial flow. With contrast-enhanced echocardiography the endocardial borders were clearly demarcated, allowing for visualization of trabecular recesses and intratrabecular flow. Contrast-enhanced echocardiography facilitates the diagnosis of noncompaction of the ventricular myocardium, circumventing the need for invasive diagnostic testing.