Histopathological study of healing after allogenic mesenchymal stem cell delivery in myocardial infarction in dogs.

In this histological study, we assessed the role of mesenchymal stem cells (MSCs) in the healing process that takes place during the subacute phase of myocardial infarction in dogs. Seven days after occlusion of the left anterior descending coronary artery, adult mongrel dogs received 100 x 10(6) 4'-6-diamidino-2-phenylindole (DAPI)-labeled allogenic bone marrow-derived MSCs by the transendocardial (TE, n=6) and intracoronary (IC, n=4) routes; control dogs (n=6) received no infusion. The dogs were euthanized at 21 days after occlusion. Hearts were excised and sliced from apex to base into four transverse sections, which were divided into nine segments. Paraffin sections from each segment were stained with hematoxylin and eosin, trichrome, picrosirius red, and antibodies against several extracellular matrix components. Frozen sections were immunostained for host cardiac phenotypical markers and analyzed by epifluorescence and deconvolution fluorescence microscopy (DFM). We found less unresolved necrotic myocardium and more extracellular matrix deposition in MSC-treated dogs than in controls 2 weeks after cell delivery. By DFM, no DAPI+ MSC nuclei were observed within native cardiac cells. MSCs delivered during the subacute phase of acute myocardial infarction positively affect healing, apparently by mechanisms other than differentiation into mature native cardiac cells.

Comparison of intracoronary and transendocardial delivery of allogeneic mesenchymal cells in a canine model of acute myocardial infarction.

This study assessed safety of transendocardial (TE) electromechanical-guided delivery of bone marrow mesenchymal stem cells (MSCs) after acute myocardial infarction (AMI) and compared intracoronary (IC) delivery with TE delivery. In a canine acute myocardial ischemia model, 100 x 10(6) MSCs were delivered 7 days after AMI via IC and TE routes. Functional assessment was performed by 2D echocardiogram, and detailed histopathologic analyses were performed to assess the impact of cell therapy in vascular density and fibrosis. Patterns of cell distribution in both delivery methods were also compared. There was a statistically significant reduction in the amount of myocardial ischemia in the TE group (P=0.007). Left ventricular ejection fraction (LVEF) increased 13% (mean) in the TE group (21-day follow-up) and was significantly better than that of the controls (P=0.01), but did not improve in the IC-delivery group. Dissimilar patterns of cell distribution were noted between the IC and TE groups. This study suggests that MSC treatment is probably safe and effective after AMI. In the comparison of TE and IC delivery, the TE group showed higher cell retention (clusters even in the injury center of the infarct) with an increased vascularity and greater functional improvement than did the IC group (no clusters; cells at the border of the infarct). The higher local cell density in the TE group may be important for therapeutic effectiveness.

Transendocardial autologous bone marrow mononuclear cell injection in ischemic heart failure: postmortem anatomicopathologic and immunohistochemical findings.

BACKGROUND: Cell-based therapies for treatment of ischemic heart disease are currently under investigation. We previously reported the results of a phase I trial of transendocardial injection of autologous bone marrow mononuclear (ABMM) cells in patients with end-stage ischemic heart disease. The current report focuses on postmortem cardiac findings from one of the treated patients, who died 11 months after cell therapy. METHODS AND RESULTS: Anatomicopathologic, morphometric, and immunocytochemical findings from the anterolateral ventricular wall (with cell therapy) were compared with findings from the interventricular septum (normal perfusion and no cell therapy) and from the inferoposterior ventricular wall (extensive scar tissue and no cell therapy). No signs of adverse events were found in the cell-injected areas. Capillary density was significantly higher (P<0.001) in the anterolateral wall than in the previously infarcted tissue in the posterior wall. The prominent vasculature of the anterolateral wall was associated with hyperplasia of pericytes, mural cells, and adventitia. Some of these cells had acquired cytoskeletal elements and contractile proteins (troponin, sarcomeric alpha-actinin, actinin), as well as the morphology of cardiomyocytes, and appeared to have migrated toward adjacent bundles of cardiomyocytes. CONCLUSIONS: Eleven months after treatment, morphological and immunocytochemical analysis of the sites of ABMM cell injection showed no abnormal cell growth or tissue lesions and suggested that an active process of angiogenesis was present in both the fibrotic cicatricial tissue and the adjacent cardiac muscle. Some of the pericytes had acquired the morphology of cardiomyocytes, suggesting long-term sequential regeneration of the cardiac vascular tree and muscle.

[Sustained improvement in symptoms and exercise capacity up to six months after autologous transendocardial transplantation of bone marrow mononuclear cells in patients with severe ischemic heart disease]. / Melhora sintomática e da capacidade de exercício após o transplante autólogo, transendocárdico, de células mononucleares da medula óssea em pacientes com cardiopatia isquêmica grave, sustentada até o sexto mês de evolução.

OBJECTIVE: This study aimed at assessing the effects of autologous transendocardial transplantation of bone marrow mononuclear cells (ATTBMMC) on symptoms, exercise capacity, myocardial perfusion and contractility in patients with severe ischemic heart disease during a 6-month follow-up period. METHODS: This prospective study comprised 21 patients as follows: the first 14 patients forming the treated group, and the last 7 patients forming the control group. Initially, all patients underwent clinical and laboratory assessment, treadmill testing, echocardiography, myocardial scintigraphy, and 24-hour Holter. The bone marrow mononuclear cells (BMMC) were isolated, washed, and diluted in 0.9% saline solution for transendocardial injection in areas of viable myocardium in the treated group, (15 0.2-mL injections). All patients were reassessed in the end of 2 and 6 months of follow-up. RESULTS: The demographic data and other characteristics did not significantly differ between the groups in the initial evaluation. No major adverse events related to the ATTBMMC were observed. In the end of 6 months, a reduction in the ischemic area was observed on nuclear perfusion imaging (P=0.05), as was a significant improvement in symptoms, functional capacity, and left ventricular overall function. CONCLUSION: This study showed that transendocardial injections of BMMC are safe in human beings with ischemic heart disease associated with severe ventricular dysfunction. The effects observed in the short run were maintained up to the sixth month of follow-up.

Melhora sintomática e da capacidade de exercício após o transplante autólogo, transendocárdico, de células mononucleares da medula óssea em pacientes com cardiopatia isquêmica grave, sustentada até o sexto mês de evolução / Sustained improvement in symptoms and exercise capacity up to six months after autologous transendocardial transplantation of bone marrow mononuclear cells in patients with severe ischemic heart disease

OBJETIVO: Este estudo tem por objetivo avaliar os efeitos, no seguimento de 6 meses, do transplante autólogo, transendocárdico, de células mononucleares da medula óssea (TACMMO), sobre os sintomas, capacidade de exercício, perfusão e contratilidade miocárdica nos portadores de cardiopatia isquêmica grave. MÉTODOS: Vinte e um pacientes foram incluídos neste estudo prospectivo (os 14 primeiros pacientes, grupo tratado; os 7 últimos pacientes, grupo controle). Inicialmente todos os indivíduos foram submetidos à avaliação clínica e laboratorial, teste ergométrico, ecocardiograma, cintilografia miocárdica e Holter de 24 horas. As CMMO foram isoladas, lavadas e diluídas em salina 0,9 por cento para injeção transendocárdica em áreas de miocárdio viável no grupo tratado, (15 injeções de 0,2 ml). Todos os pacientes foram reavaliados ao final de 2 e 6 meses de acompanhamento. RESULTADOS: Os dados demográficos e demais características não diferiram significativamente entre os grupos na avaliação inicial. Não foram observados eventos adversos maiores relacionados ao TACMMO. Ao final de 6 meses, houve redução da área isquêmica na imagem de perfusão nuclear (p=0,05) e melhora significativa dos sintomas, da capacidade funcional e da função global do ventrículo esquerdo. CONCLUSAO: Este estudo demonstra a segurança da realização de injeções transendocárdicas de CMMO em humanos com cardiopatia isquêmica associada a grave disfunção ventricular. Os efeitos observados em curto prazo foram mantidos até 6 meses de acompanhamento.

Mesenchymal stem cells differentiate into an endothelial phenotype, enhance vascular density, and improve heart function in a canine chronic ischemia model.

BACKGROUND: Bone marrow-derived stem cells are under investigation as a treatment for ischemic heart disease. Mesenchymal stem cells (MSCs) have been used preferentially in the acute ischemia model; data in the chronic ischemia model are lacking. METHODS AND RESULTS: Twelve dogs underwent ameroid constrictor placement. Thirty days later, they received intramyocardial injections of either MSCs (100x10(6) MSCs/10 mL saline) (n=6) or saline only (10 mL) (controls) (n=6). All were euthanized at 60 days. Resting and stress 2D echocardiography was performed at 30 and 60 days after ameroid placement. White blood cell count (WBC), C-reactive protein (CRP), creatine kinase MB (CK-MB), and troponin I levels were measured. Histopathological and immunohistochemical analyses were performed. Mean left ventricular ejection fraction was similar in both groups at baseline but significantly higher in treated dogs at 60 days. WBC and CRP levels were similar over time in both groups. CK-MB and troponin I increased from baseline to 48 hours, eventually returning to baseline. There was a trend toward reduced fibrosis and greater vascular density in the treated group. MSCs colocalized with endothelial and smooth muscle cells but not with myocytes. CONCLUSIONS: In a canine chronic ischemia model, MSCs differentiated into smooth muscle cells and endothelial cells, resulting in increased vascularity and improved cardiac function.

Catheter-based transendocardial delivery of autologous bone-marrow-derived mononuclear cells in patients listed for heart transplantation.

Growing evidence suggests that transplantation of autologous bone-marrow mononuclear cells (ABMMNCs) can improve the perfusion and contractile function of ischemic myocardium. This procedure could potentially benefit transplant candidates awaiting a donor heart. To study the safety and feasibility of ABMMNC injection, we performed a prospective, nonrandomized, open-label study in 5 heart transplant candidates with severe ischemic heart failure. Each patient underwent baseline single-photon emission computed tomography, a ramp treadmill protocol, 2-dimensional echocardiography, 24-hour Holter monitoring, and signal-averaged electrocardiography, which were repeated at 2 and 6 months. Transendocardial delivery of ABMMNCs was done with the aid of electromechanical mapping to identify viable myocardium. Each patient received 15 ABMMNC injections of 0.2 cc each. There were no deaths, significant arrhythmias, or other major complications. The ABMMNC injection reduced the amount of ischemic myocardium (not statistically significant). More important, exercise test results improved significantly. Myocardial volume oxygen consumption increased from 10.6 +/- 3 mL/kg/min (baseline) to 16.3 +/- 7 mL/kg/min (2 months) and 23 +/- 7 mL/kg/min (6 months) (P = 0.0091). In 4 of the 5 cases, this was such an improvement that the patients were no longer eligible for cardiac transplantation. In addition, metabolic equivalents improved from 3.03 +/- 0.66 (baseline) to 4.65 +/- 1.99 (2 months) and 6.5 +/- 2.0 (6 months) (P = 0.0092). In conclusion, ABMMNC injections were performed safely and resulted in improved exercise capacity. This technique may hold promise as an alternative to medical management in patients with severe ischemic heart failure who are ineligible for conventional revascularization.

Improved exercise capacity and ischemia 6 and 12 months after transendocardial injection of autologous bone marrow mononuclear cells for ischemic cardiomyopathy.

BACKGROUND: We recently reported the safety and feasibility of autologous bone marrow mononuclear cell (ABMMNC) injection into areas of ischemic myocardium in patients with end-stage ischemic cardiomyopathy. The present study evaluated the safety and efficacy of this therapy at 6- and 12-month follow-up. METHODS AND RESULTS: Twenty patients with 6- and 12-month follow-up (11 treated subjects; 9 controls) were enrolled in this prospective, nonrandomized, open-label study. Complete clinical and laboratory evaluations as well as exercise stress (ramp treadmill), 2-dimensional Doppler echocardiography, single-photon emission computed tomography (SPECT) perfusion scanning, and 24-hour Holter monitoring were performed at baseline and follow-up. Transendocardial delivery of ABMMNCs was performed with the aid of electromechanical mapping to identify viable myocardium. Each patient received 15 ABMMNC injections of 0.2 mL each. At 6 and 12 months, total reversible defect, as measured by SPECT perfusion scanning, was significantly reduced in the treatment group as compared with the control group. At 12 months, exercise capacity was significantly improved in the treatment group. This improvement correlated well with monocyte, B-cell, hematopoietic progenitor cell, and early hemapoietic progenitor cell phenotypes. CONCLUSIONS: The 6- and 12-month follow-up data in this study suggest that transendocardial injection of ABMMNCs in patients with end-stage ischemic heart disease may produce a durable therapeutic effect and improve myocardial perfusion and exercise capacity.

Transendocardial, autologous bone marrow cell transplantation for severe, chronic ischemic heart failure.

BACKGROUND: This study evaluated the hypothesis that transendocardial injections of autologous mononuclear bone marrow cells in patients with end-stage ischemic heart disease could safely promote neovascularization and improve perfusion and myocardial contractility. METHODS AND RESULTS: Twenty-one patients were enrolled in this prospective, nonrandomized, open-label study (first 14 patients, treatment; last 7 patients, control). Baseline evaluations included complete clinical and laboratory evaluations, exercise stress (ramp treadmill), 2D Doppler echocardiogram, single-photon emission computed tomography perfusion scan, and 24-hour Holter monitoring. Bone marrow mononuclear cells were harvested, isolated, washed, and resuspended in saline for injection by NOGA catheter (15 injections of 0.2 cc). Electromechanical mapping was used to identify viable myocardium (unipolar voltage > or =6.9 mV) for treatment. Treated and control patients underwent 2-month noninvasive follow-up, and treated patients alone underwent a 4-month invasive follow-up according to standard protocols and with the same procedures used as at baseline. Patient population demographics and exercise test variables did not differ significantly between the treatment and control groups; only serum creatinine and brain natriuretic peptide levels varied in laboratory evaluations at follow-up, being relatively higher in control patients. At 2 months, there was a significant reduction in total reversible defect and improvement in global left ventricular function within the treatment group and between the treatment and control groups (P=0.02) on quantitative single-photon emission computed tomography analysis. At 4 months, there was improvement in ejection fraction from a baseline of 20% to 29% (P=0.003) and a reduction in end-systolic volume (P=0.03) in the treated patients. Electromechanical mapping revealed significant mechanical improvement of the injected segments (P<0.0005) at 4 months after treatment. CONCLUSIONS: Thus, the present study demonstrates the relative safety of intramyocardial injections of bone marrow-derived stem cells in humans with severe heart failure and the potential for improving myocardial blood flow with associated enhancement of regional and global left ventricular function.