Project description:Stem cell transplantation is emerging as a potential therapy to treat heart diseases. Promising results from early animal studies led to an explosion of small, non-controlled clinical trials that created even further excitement by showing that stem cell transplantation improved left ventricular systolic function and enhanced remodelling. However, the specific mechanisms by which these cells improve heart function remain largely unknown. A large variety of cell types have been considered to possess the regenerative ability needed to repair the damaged heart. One of the most studied cell types is the bone marrow-derived mononuclear cells and these form the focus of this review. This review article aims to provide an overview of their use in the setting of acute myocardial infarction, the challenges it faces and the future of stem cell therapy in heart disease.
Project description:In spite of modern treatment, acute myocardial infarction (AMI) still carries significant morbidity and mortality worldwide. Even though standard of care therapy improves symptoms and also long-term prognosis of patients with AMI, it does not solve the critical issue, specifically the permanent damage of cardiomyocytes. As a result, a complex process occurs, namely cardiac remodeling, which leads to alterations in cardiac size, shape and function. This is what has driven the quest for unconventional therapeutic strategies aiming to regenerate the injured cardiac and vascular tissue. One of the latest breakthroughs in this regard is stem cell (SC) therapy. Based on favorable data obtained in experimental studies, therapeutic effectiveness of this innovative therapy has been investigated in clinical settings. Of various cell types used in the clinic, autologous bone marrow derived SCs were the first used to treat an AMI patient, 15 years ago. Since then, we have witnessed an increasing body of data as regards this cutting-edge therapy. Although feasibility and safety of SC transplant have been clearly proved, it's efficacy is still under dispute. Conducted studies and meta-analysis reported conflicting results, but there is hope for conclusive answer to be provided by the largest ongoing trial designed to demonstrate whether this treatment saves lives. In the meantime, strategies to enhance the SCs regenerative potential have been applied and/or suggested, position papers and recommendations have been published. But what have we learned so far and how can we properly use the knowledge gained? This review will analytically discuss each of the above topics, summarizing the current state of knowledge in the field.
Project description:To investigate the effect of transplantation of stem cells from the bone marrow mononuclear cells (BMMC) associated with 15d-PGJ2-loaded nanoparticles in a rat model of chronic MI. Chronic myocardial infarction (MI) was induced by the ligation of the left anterior descending artery in 40 male Wistar rats. After surgery, we transplanted bone marrow associated with 15d-PGJ2-loaded nanoparticle by intramyocardial injection (106 cells/per injection) seven days post-MI. Myocardial infarction was confirmed by echocardiography, and histological analyses of infarct morphology, gap junctions, and angiogenesis were obtained. Our results from immunohistochemical analyses demonstrated the presence of angiogenesis identified in the transplanted region and that there was significant expression of connexin-43 gap junctions, showing a more effective electrical and mechanical integration of the host myocardium. This study suggests that the application of nanoparticle technology in the prevention and treatment of MI is an emerging field and can be a strategy for cardiac repair.
Project description:BackgroundAcute myocardial infarction (AMI) launches an inflammatory response and a repair process to compensate cardiac function. During this process, the balance between proinflammatory and anti-inflammatory cytokines is important for optimal cardiac repair. Stem cell transplantation after AMI improves tissue repair and increases the ventricular ejection fraction. Here, we studied in detail the acute effect of bone marrow mononuclear cell (BMMNC) transplantation on proinflammatory and anti-inflammatory cytokines in patients with ST segment elevation myocardial infarction (STEMI).MethodsPatients with STEMI treated with thrombolysis followed by percutaneous coronary intervention (PCI) were randomly assigned to receive either BMMNC or saline as an intracoronary injection. Cardiac function was evaluated by left ventricle angiogram during the PCI and again after 6 months. The concentrations of 27 cytokines were measured from plasma samples up to 4 days after the PCI and the intracoronary injection.ResultsTwenty-six patients (control group, n = 12; BMMNC group, n = 14) from the previously reported FINCELL study (n = 80) were included to this study. At day 2, the change in the proinflammatory cytokines correlated with the change in the anti-inflammatory cytokines in both groups (Kendall's tau, control 0.6; BMMNC 0.7). At day 4, the correlation had completely disappeared in the control group but was preserved in the BMMNC group (Kendall's tau, control 0.3; BMMNC 0.7).ConclusionsBMMNC transplantation is associated with preserved balance between pro- and anti-inflammatory cytokines after STEMI in PCI-treated patients. This may partly explain the favorable effect of stem cell transplantation after AMI.
Project description:BackgroundThe effect of bone marrow-derived mononuclear cells (BM-MNCs) after acute myocardial infarction (AMI) on myocardial function indices such as left ventricular ejection fraction has been widely studied. However, the effect of this intervention on major adverse cardiovascular events (MACE) was not the principal purpose of most investigations and its role is unclear. The aim of this study was to investigate the possible long-term clinical efficacy of BM-MNCs on MACE after AMI.MethodsA comprehensive search was conducted through electronic databases for potentially eligible randomized trials investigating the impact of BM-MNC therapy following acute MI on clinical outcomes. Risk of bias of the eligible studies was assessed using the Cochrane Collaboration's tool. The effect of treatment was displayed by risk ratio (RR) and its 95% confidence interval (CI) using random-effects model.ResultsInitial database searching found 1540 records and 23 clinical trials with a total of 2286 participants eligible for meta-analysis. Injection of BM-MNCs was associated with lower risk of composite end points of hospitalization for congestive heart failure (CHF), re-infarction, and cardiac-related mortality (91/1191 vs. 111/812, RR = 0.643, 95% CI = 0.489 to 0.845, p = 0.002). This effect was derived from both reduction of CHF (47/1220 vs. 62/841, RR = 0.568, 95% CI = 0.382 to 0.844, p = 0.005) and re-infarction rate (23/1159 vs. 30/775, RR = 0.583, 95% CI = 0.343 to 0.991, p = 0.046), but not cardiac-related mortality (28/1290 vs. 31/871, RR = 0.722, 95% CI = 0.436 to 1.197, p = 0.207).ConclusionThis is the first meta-analysis focused on the cardiovascular outcomes of stem cell therapy after AMI and it revealed that transplantation of BM-MNCs may reduce composite endpoint of hospitalization for CHF, re-infarction, and cardiac related mortality driven mainly by reducing reinfarction and hospitalization for heart failure rates but not cardiovascular mortality.
Project description:Wide variation exists in the extent (number and diameter) of native pre-existing collaterals in tissues of different strains of mice, with supportive indirect evidence recently appearing for humans. This variation is a major determinant of the wide variation in severity of tissue injury in occlusive vascular disease. Whether such genetic-dependent variation also exists in the heart is unknown because no model exists for study of mouse coronary collaterals. Also owing to methodological limitations, it is not known if ischemia can induce new coronary collaterals to form ("neo-collaterals") versus remodeling of pre-existing ones. The present study sought to develop a model to study coronary collaterals in mice, determine whether neo-collateral formation occurs, and investigate the responsible mechanisms. Four strains with known rank-ordered differences in collateral extent in brain and skeletal muscle were studied: C57BLKS>C57BL/6>A/J>BALB/c. Unexpectedly, these and 5 additional strains lacked native coronary collaterals. However after ligation, neo-collaterals formed rapidly within 1-to-2 days, reaching their maximum extent in ≤7 days. Rank-order for neo-collateral formation differed from the above: C57BL/6>BALB/c>C57BLKS>A/J. Collateral network conductance, infarct volume(-1), and contractile function followed this same rank-order. Neo-collateral formation and collateral conductance were reduced and infarct volume increased in MCP1(-/-) and CCR2(-/-) mice. Bone-marrow transplant rescued collateral formation in CCR2(-/-) mice. Involvement of fractalkine➔CX3CR1 signaling and endothelial cell proliferation were also identified. This study introduces a model for investigating the coronary collateral circulation in mice, demonstrates that neo-collaterals form rapidly after coronary occlusion, and finds that MCP➔CCR2-mediated recruitment of myeloid cells is required for this process.
Project description:To understand the role of bone marrow mononuclear cells in the treatment of acute myocardial infarction, this overview offers a retrospective examination of strengths and limitations of 3 contemporaneous trials with attention to critical design features and provides an analysis of the combined data set and implications for future directions in cell therapy for acute myocardial infarction.
Project description:IntroductionMost studies on intracoronary bone marrow mononuclear cell transplantation for acute myocardial infarction involve treatment 3-7 days after primary percutaneous coronary intervention (PCI); however, the optimal timing is unknown. The present study assessed the therapeutic effect at different times after ST-elevation myocardial infarction.MethodsThe present trial was not blinded. A total of 104 patients with a first ST-elevation myocardial infarction and a left ventricular ejection fraction below 50 %, who had PCI of the infarct-related artery, were randomly assigned to receive intracoronary infusion of bone marrow mononuclear cells within 24 hours (group A, n = 27), 3 to 7 days after PCI (group B, n = 26), or 7 to 30 days after PCI (group C, n = 26), or to the control group (n = 25), which received saline infusion performed immediately after emergency PCI. All patients in groups A, B and C received an injection of 15 ml cell suspension containing approximately 4.9 × 10(8) bone marrow mononuclear cells into the infarct-related artery after successful PCI.ResultsCompared to control and group C patients, group A and B patients had a significantly higher absolute increase in left ventricular ejection fraction from baseline to 12 months (change: 3.4 ± 5.7 % in control, 7.9 ± 4.9 % in group A, 6.9 ± 3.9 % in group B, 4.7 ± 3.7 % in group C), a greater decrease in left ventricular end-systolic volumes (change: -6.4 ± 15.9 ml in control, -20.5 ± 13.3 ml in group A, -19.6 ± 11.1 ml in group B, -9.4 ± 16.3 ml in group C), and significantly greater myocardial perfusion (change from baseline: -4.7 ± 5.7 % in control, -7.8 ± 4.5 % in group A, -7.5 ± 2.9 % in group B, -5.0 ± 4.0 % in group C). Group A and B patients had similar beneficial effects on cardiac function (p = 0.163) and left ventricular geometry (left ventricular end-distolic volume: p = 0.685; left ventricular end-systolic volume: p = 0.622) assessed by echocardiography, whereas group C showed similar results to those of the control group. Group B showed more expensive care (p < 0.001) and longer hospital stays during the first month after emergency PCI (p < 0.001) than group A, with a similar improvement after repeat cardiac catheterization following emergency PCI.ConclusionCell therapy in acute myocardial infarction patients that is given within 24 hours is similar to 3-7 days after the primary PCI.Trial registrationNCT02425358 , registered 30 April 2015.
Project description:BackgroundInitial clinical trials from Europe have demonstrated that the administration of bone marrow-derived mononuclear cells (BMCs) may improve left ventricular (LV) function in patients following ST-elevation myocardial infarction (STEMI). However, results from trials performed in the United States have not yet been presented.MethodsWe developed a phase 1, randomized, placebo-controlled, double-blind trial to investigate the effects of BMC administration in patients following STEMI on recovery of LV function using cardiac magnetic resonance imaging (cMRI). Forty patients with moderate to large anterior STEMIs were randomized to 100 million intracoronary BMCs versus placebo 3 to 10 days following successful primary angioplasty and stenting (percutaneous coronary intervention) of the left anterior descending coronary artery.ResultsAdministration of BMC was safely performed in a high-risk cohort with minimal major adverse clinical event rates, and all patients remain alive to date. Left ventricular ejection fraction increased from 49.0% +/- 9.5% at baseline to 55.2% +/- 9.8% at 6 months by cMRI in the BMC group (P < .05), which was not different from the increase in the placebo group (48.6% +/- 8.5% to 57.0% +/- 13.4%, P < .05). Left ventricular end-diastolic volume decreased by 4 mL/m(2) in the BMC group at 6 months but increased significantly in the placebo group (17 mL/m(2), P < .01).ConclusionsThis phase 1 study from the United States confirms the ongoing safety profile of BMC administration in patients following STEMI. The improvement in LV ejection fraction at 6 months by cMRI in the cell therapy group was not different than the placebo group. However, BMC administration had a favorable effect on LV remodeling at 6 months.
Project description:Myocardial infarction (MI) and osteoporotic fracture are leading causes of morbidity and mortality, and epidemiological evidence linking their incidence suggests possible crosstalk. MI can exacerbate atherosclerosis through the sympathetic nervous system (SNS) activation and β3 adrenoreceptor-mediated release of hematopoietic stem cells, leading to monocytosis. We hypothesized that this same pathway initiates systemic bone loss following MI, since osteoclasts differentiate from monocytes. In this study, MI was created with left anterior descending artery ligation in 12-week-old male mice (n = 24) randomized to β3 -adrenergic receptor (AR) antagonist (SR 59230A) treatment or no treatment for 10 days postoperatively. Additional mice (n = 21, treated and untreated) served as unoperated controls. Bone mineral density (BMD), bone mineral content (BMC), and body composition were quantified at baseline and 10 days post-MI using dual-energy x-ray absorptiometry; circulating monocyte levels were quantified and the L5 vertebral body and femur were analyzed with microcomputed tomography 10 days post-MI. We found that MI led to circulating monocyte levels increases, BMD and BMC decreases at the femur and lumbar spine in MI mice (-6.9% femur BMD, -3.5% lumbar BMD), and trabecular bone volume decreases in MI mice compared with control mice. β3 -AR antagonist treatment appeared to diminish the bone loss response (-5.3% femur BMD, -1.2% lumbar BMD), though these results were somewhat inconsistent. Clinical significance: These results suggest that MI leads to systemic bone loss, but that the SNS may not be a primary modulator of this response; bone loss and increased fracture risk may be important clinical comorbidities following MI or other ischemic injuries.