Implantation of a Novel Allogeneic Mesenchymal Precursor Cell Type in Patients with Ischemic Cardiomyopathy Undergoing Coronary Artery Bypass Grafting: an Open Label Phase IIa Trial

20 years of treating ischemic cardiomyopathy with mesenchymal stromal cells: a meta-analysis and systematic review

This meta-analysis and systematic review compiles comparative data from 2004 to 2024, investigating the safety and efficacy of mesenchymal stem/stromal cells (MSCs) derived from various tissues for the treatment of ischemic cardiomyopathy (ICM) and associated heart failure. In addition, this review highlights the limitations of these interventions and provides valuable insights for future therapeutic approaches. Relevant articles were retrieved from the PubMed® database using targeted keywords. Our inclusion criteria included clinical trials with patients over 18 years of age, case reports and pilot studies. Animal experiments, in vitro studies, correlational and longitudinal studies, and study designs and protocols were excluded. Forty-nine original articles resulted in follow-up reports of 45 trials. MSCs from bone marrow, umbilical cord and adipose tissue were moderately well tolerated. Of the 1408 participants who received MSCs, 33 trials (67.3%) reported the occurrence of death or serious adverse events. These events resulted in 80 deaths (52% of reported cases) following MSC administration. Importantly, 41.3% of these deaths (n = 33) were not considered to be related to the intervention itself, while 40% of these deaths had no reported cause. As the primary outcome, the mean increase in left ventricular ejection fraction (LVEF) from baseline was 5.75% (95% CI: 3.38% -8.11%, p < 0.0001, I2 = 90,9%) in the randomized controlled trials only (n = 24) within the treatment groups and 3.19% (95% CI: 1.63% to 4.75%, p < 0.0001, I2 = 74,17%) in the control groups after the intervention. When the above results were compared using the standardized mean difference (SDM), a significance in favor of the treatment group was also found (SDM = 0.41; 95% CI: 0.19-0.64, p < 0.001, I2 = 71%). Although improvements were also seen in the control groups, 33.3% (n = 15) of the studies showed no significant difference between the control and treatment groups. The 6-minute walking test (6MWT) and New York Heart Association (NYHA) class scores, used for assessing exercise tolerance and quality of life (QoL), respectively, further supported the improvements in the treatment group. These improvements were noted as 62.5% (n = 10) for the 6MWT and 54.5% (n = 12) for the NYHA class scores. According to the risk of bias analysis, 4 trials were of good quality (11.8%), 15 were of fair quality (44.1%), and 15 were of poor quality (44.1%). Major limitations of these studies included small sample size, diagnostic challenges/lack, uncertain cell dosage and potential bias in patient selection. Despite the ongoing debate surrounding cell administration for ICM, there are supporting signs of improved clinical and laboratory outcomes, as well as improved QoL in the MSC-treated groups. However, it is important to recognize the limitations of each study, highlighting the need for larger, controlled trials to validate these findings.

Cellular and molecular mechanisms driving cardiac tissue fibrosis: On the precipice of personalized and precision medicine

Cardiac fibrosis is a significant contributor to heart failure, a condition that continues to affect a growing number of patients worldwide. Various cardiovascular comorbidities can exacerbate cardiac fibrosis. While fibroblasts are believed to be the primary cell type underlying fibrosis, recent and emerging data suggest that other cell types can also potentiate or expedite fibrotic processes. Over the past few decades, clinicians have developed therapeutics that can blunt the development and progression of cardiac fibrosis. While these strategies have yielded positive results, overall clinical outcomes for patients suffering from heart failure continue to be dire. Herein, we overview the molecular and cellular mechanisms underlying cardiac tissue fibrosis. To do so, we establish the known mechanisms that drive fibrosis in the heart, outline the diagnostic tools available, and summarize the treatment options used in contemporary clinical practice. Finally, we underscore the critical role the immune microenvironment plays in the pathogenesis of cardiac fibrosis.

Mesenchymal stem cells and COVID-19: What they do and what they can do

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or coronavirus disease 2019 (COVID-19) pandemic has exhausted the health systems in many countries with thousands cases diagnosed daily. The currently used treatment guideline is to manage the common symptoms like fever and cough, but doesn't target the virus itself or halts serious complications arising from this viral infection. Currently, SARS-CoV-2 exhibits many genetic modulations which have been associated with the appearance of highly contagious strains. The number of critical cases of COVID-19 increases markedly, and many of the infected people die as a result of respiratory failure and multiple organ dysfunction. The regenerative potential of mesenchymal stem cells (MSCs) has been extensively studied and confirmed. The impressive immunomodulation and anti-inflammatory activity of MSCs have been recognized as a golden opportunity for the treatment of COVID-19 and its associated complications. Moreover, MSCs regenerative and repairing abilities have been corroborated by many studies with positive outcomes and high recovery rates. Based on that, MSCs infusion could be an effective mechanism in managing and stemming the serious complications and multiple organ failure associated with COVID-19. In the present review, we discuss the commonly reported complications of COVID-19 viral infection and the established and anticipated role of MSCs in managing these complications.

Mesenchymal Stem Cells Therapies on Fibrotic Heart Diseases

Stem cell therapy is a promising alternative approach to heart diseases. The most prevalent source of multipotent stem cells, usually called somatic or adult stem cells (mesenchymal stromal/stem cells, MSCs) used in clinical trials is bone marrow (BM-MSCs), adipose tissue (AT-MSCs), umbilical cord (UC-MSCs) and placenta. Therapeutic use of MSCs in cardiovascular diseases is based on the benefits in reducing cardiac fibrosis and inflammation that compose the cardiac remodeling responsible for the maintenance of normal function, something which may end up causing progressive and irreversible dysfunction. Many factors lead to cardiac fibrosis and failure, and an effective therapy is lacking to reverse or attenuate this condition. Different approaches have been shown to be promising in surpassing the poor survival of transplanted cells in cardiac tissue to provide cardioprotection and prevent cardiac remodeling. This review includes the description of pre-clinical and clinical investigation of the therapeutic potential of MSCs in improving ventricular dysfunction consequent to diverse cardiac diseases.

The Role of MSC Therapy in Attenuating the Damaging Effects of the Cytokine Storm Induced by COVID-19 on the Heart and Cardiovascular System

The global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) has led to 47 m infected cases and 1. 2 m (2.6%) deaths. A hallmark of more severe cases of SARS-CoV-2 in patients with acute respiratory distress syndrome (ARDS) appears to be a virally-induced over-activation or unregulated response of the immune system, termed a "cytokine storm," featuring elevated levels of pro-inflammatory cytokines such as IL-2, IL-6, IL-7, IL-22, CXCL10, and TNFα. Whilst the lungs are the primary site of infection for SARS-CoV-2, in more severe cases its effects can be detected in multiple organ systems. Indeed, many COVID-19 positive patients develop cardiovascular complications, such as myocardial injury, myocarditis, cardiac arrhythmia, and thromboembolism, which are associated with higher mortality. Drug and cell therapies targeting immunosuppression have been suggested to help combat the cytokine storm. In particular, mesenchymal stromal cells (MSCs), owing to their powerful immunomodulatory ability, have shown promise in early clinical studies to avoid, prevent or attenuate the cytokine storm. In this review, we will discuss the mechanistic underpinnings of the cytokine storm on the cardiovascular system, and how MSCs potentially attenuate the damage caused by the cytokine storm induced by COVID-19. We will also address how MSC transplantation could alleviate the long-term complications seen in some COVID-19 patients, such as improving tissue repair and regeneration.

Can we remove scar and fibrosis from adult human myocardium?

The pathological processes leading to heart failure are characterized by the formation of fibrosis and scar, yet the dynamics of scar production and removal are incompletely understood. Spontaneous disappearance of myocardial collagen is reported in infancy but doubted in adulthood where scar volume constitutes a better prognostic indicator than the conventional parameters of ventricular function. Whilst certain drugs are known to attenuate myocardial fibrosis evidence is emerging that stem cell therapy also has the potential to reduce scar size and improve myocardial viability. Both animal studies and clinical trials support the concept that, as in infancy, cellular processes can be triggered to remove collagen and regenerate injured myocardium. The molecular mechanisms likely involve anti-fibrotic cytokines growth factors and matrix-metalloproteinases. Autologous cardiac, bone-marrow and adipose tissue derived stem cells have each shown efficacy. Specific immune privileged mesenchymal stem cells and genetically modified immunomodulatory progenitor cells may in turn provide an allogenic source for the paracrine effects. Thus autologous and allogenic cells both have the potential through paracrine action to reduce scar volume, boost angiogenesis and improve ventricular morphology. The potential benefit of myocardial cell therapy for routine treatment of heart failure is an area that requires further study.

Recent Progress in Stem Cell Modification for Cardiac Regeneration

During the past decades, stem cell-based therapy has acquired a promising role in regenerative medicine. The application of novel cell therapeutics for the treatment of cardiovascular diseases could potentially achieve the ambitious aim of effective cardiac regeneration. Despite the highly positive results from preclinical studies, data from phase I/II clinical trials are inconsistent and the improvement of cardiac remodeling and heart performance was found to be quite limited. The major issues which cardiac stem cell therapy is facing include inefficient cell delivery to the site of injury, accompanied by low cell retention and weak effectiveness of remaining stem cells in tissue regeneration. According to preclinical and clinical studies, various stem cells (adult stem cells, embryonic stem cells, and induced pluripotent stem cells) represent the most promising cell types so far. Beside the selection of the appropriate cell type, researchers have developed several strategies to produce “second-generation” stem cell products with improved regenerative capacity. Genetic and nongenetic modifications, chemical and physical preconditioning, and the application of biomaterials were found to significantly enhance the regenerative capacity of transplanted stem cells. In this review, we will give an overview of the recent developments in stem cell engineering with the goal to facilitate stem cell delivery and to promote their cardiac regenerative activity.

Cell therapy for heart disease after 15 years: Unmet expectations

Over the past two decades cardiac cell therapy (CCT) has emerged as a promising new strategy to cure heart diseases at high unmet need. Thousands of patients have entered clinical trials for acute or chronic heart conditions testing different cell types, including autologous or allogeneic bone marrow (BM)-derived mononuclear or selected cells, BM- or adipose tissue-derived mesenchymal cells, or cardiac resident progenitors based on their potential ability to regenerate scarred or dysfunctional myocardium. Nowadays, the original enthusiasm surrounding the regenerative medicine field has been cushioned by a cumulative body of evidence indicating an inefficient or modest efficacy of CCT in improving cardiac function, along with the continued lack of indisputable proof for long-term prognostic benefit. In this review, we have firstly comprehensively outlined the positive and negative results of cell therapy studies in patients with acute myocardial infarction, refractory angina and chronic heart failure. Next, we have discussed cell therapy- and patient-related variables (e.g. cell intrinsic and extrinsic characteristics as well as criteria of patient selection and proposed methodologies) that might have dampened the efficacy of past cell therapy trials. Finally, we have addressed critical factors to be considered before embarking on further clinical trials.