Stem cell therapy for cardiovascular diseases: Mechanisms, challenges, and therapeutic prospects

*Corresponding author: Silas Samuel Abraham. Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Stem cell therapy for cardiovascular diseases: Mechanisms, challenges, and therapeutic prospects Silas Samuel Abraham 1, * and Aditya Shukla 2 1 Grade 12, Great Harvest Vidyalaya (CBSE), Morai, Avadi, Chennai-600055, India. 2 Department of Microbiology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata700019, India. World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 316-321 Publication history: Received on 05 August 2025; revised on 14 September 2025; accepted on 16 September 2025 Article DOI: https://doi.org/10.30574/wjbphs.2025.23.3.0836 Abstract Cardiovascular diseases (CVDs) are the leading cause of global mortality. Stem cell therapy has emerged as a promising branch of regenerative medicine, offering innovative avenues for repairing damaged myocardial tissue. This therapy utilizes cardiac progenitor cells, mesenchymal stem cells, and induced pluripotent stem cells to promote healing via paracrine signaling, immunomodulation, and direct differentiation into cardiac cells. The therapeutic potential lies in restoring cardiac function, especially post-myocardial infarction, by reducing fibrosis and enhancing angiogenesis. However, clinical applications are limited by challenges such as poor cell retention, immune rejection, and risks of arrhythmias or tumor formation. This review explores the latest advances in stem cell-based cardiac therapies, their mechanisms of action, delivery strategies, and limitations, offering a comprehensive perspective on future directions in cardiovascular regenerative medicine. Keywords: Cardiovascular Disease; Stem Cell Therapy; Myocardial Infarction; Cardiac Regeneration; Mesenchymal Stem Cells; Ipscs; Cardiac Progenitor Cells 1. Introduction Cardiovascular diseases (CVDs) remain the leading cause of death globally, accounting for approximately 20 million deaths annually—nearly one-third of all global deaths. The burden of CVDs has increased dramatically over the past decades, rising from about 12 million deaths in 1990, which represents a significant upsurge. Ischemic heart disease and stroke are the primary contributors, responsible for approximately 9 million and 6 million deaths per year, respectively. Even during the peak of the COVID-19 pandemic in 2021, CVDs surpassed COVID-19 as the foremost global cause of death. CVDs are also a major cause of premature mortality, especially in lowand middle-income countries. In 2019, 38% of the 17 million premature non-communicable disease-related deaths (before the age of 70) were attributed to CVDs. The disease affects both men and women almost equally, with 10.5 million men and 9.6 million women succumbing to CVDs in 2021. Notably, while CVDs are the leading cause of death in women, they often receive less public attention compared to conditions such as breast cancer. Addressing and reducing the global burden of CVDs, particularly preventable early deaths, is therefore a pressing public health priority. Myocardial infarction results in irreversible myocardial tissue damage due to cardiomyocyte loss, which the adult human heart is inefficient at regenerating. The natural response involves replacing damaged tissue with non-contractile fibrotic scar tissue, leading to impaired cardiac function and progression toward heart failure. This limited regenerative ability remains a central challenge in cardiovascular medicine. World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 316-321 317 Stem cell therapy has recently emerged as a compelling strategy for regenerating injured myocardium. Stem cells possess the capacity to differentiate into cardiomyocyte-like cells and secrete paracrine factors that inhibit inflammation, stimulate angiogenesis, and support tissue repair. These characteristics make stem cell therapy particularly relevant for various forms of CVDs, including ischemic heart disease, cardiomyopathies, valvular heart disease, congenital heart defects, and arrhythmias. Conventional treatments are largely symptomatic and do not address the underlying loss of cardiomyocytes. In contrast, stem cell interventions offer the potential to restore cardiac function at a cellular level. Various types of stem cells—such as embryonic stem cells (ESCs), iPSCs, and MSCs—have been intensively investigated over the past two decades for their ability to regenerate cardiac tissue. Their ability to differentiate into cardiomyocytes, endothelial cells, and smooth muscle cells makes them highly valuable for regenerative applications. Despite their promise, stem cell therapies face several challenges, particularly in heart failure. The main issue is poor cell survival and engraftment in the hostile post-infarction environment characterized by inflammation, oxidative stress, and hypoxia. Furthermore, adult stem cells like MSCs often fail to differentiate efficiently into functionally competent cardiomyocytes, and those that do typically lack the properties needed for integration and synchronous contraction with native cardiac tissue. Inadequate integration may also lead to arrhythmias, particularly when pluripotent stem cells form immature or ectopic tissue. Even autologous cells manipulated ex vivo may provoke immune responses, and allogeneic cells carry a risk of rejection. Moreover, stem cell therapies often do not restore extracellular matrix components, limiting their ability to regenerate contractile function. While clinical trials have shown modest short-term improvements in cardiac performance, ethical issues (especially with ESCs) and inconsistencies in cell type, dosage, and delivery. 2. Cardiac Damage and Limited Regeneration Cardiac injury, particularly myocardial infarction, leads to the irreversible loss of cardiomyocytes. These highly specialized cells are essential for the contractile function and normal performance of the heart. However, lost cardiomyocytes in the adult human heart are not readily replaced due to the organ's limited proliferative capacity. Compared to tissues with high turnover rates, such as skin and gastrointestinal epithelium, the heart lacks a robust endogenous regeneration mechanism. This absence of cellular renewal results in permanent loss of contractile units and a consequent decline in overall cardiac performance. The damaged myocardium undergoes a process known as cardiac remodeling, which includes structural changes such as ventricular dilation, wall thinning, and fibrotic scarring. While fibrotic tissue is critical for structural support and preventing rupture, it does not contribute to the mechanical or electrical function of the heart. Over time, this leads to ventricular dysfunction and progression to heart failure. These pathological changes are not only irreversible but are compounded by the heart’s inadequate ability to regenerate the lost myocardial mass. The restricted regenerative capacity of the adult heart is largely due to the post-mitotic nature of cardiomyocytes. Most of these cells exit the cell cycle shortly after birth and become terminally differentiated. Although small populations of resident cardiac progenitor cells exist, their capacity to regenerate substantial functional myocardium is limited. This biological constraint presents a significant therapeutic challenge in modern cardiovascular medicine. The irreversible loss of cardiomyocytes and the inefficiency of endogenous repair mechanisms have driven growing interest in regenerative strategies, particularly those involving stem cells. Stem cells possess unique characteristics that make them promising candidates for cardiac repair: they are self-renewing, capable of multilineage differentiation, and actively participate in paracrine signaling. Among various stem cell types, mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), and induced pluripotent stem cells (iPSCs) have shown the greatest potential in animal models of myocardial injury. These cells may contribute to cardiac repair in several ways. First, they can differentiate directly into cardiomyocyte-like cells. Second, they secrete bioactive molecules that support the survival of existing heart tissue by reducing inflammation, preventing apoptosis, and promoting angiogenesis. Third, they can interact with endogenous cardiac cells to stimulate reparative responses. Despite these advantages, several obstacles hinder the clinical translation of stem cell therapies. Key issues include immunogenicity, risk of tumor formation (especially with pluripotent stem cells), poor survival and retention of transplanted cells, and difficulty in guiding appropriate differentiation. Nonetheless, advances in tissue engineering, gene editing, and biomaterial-based delivery systems continue to enhance the therapeutic potential of stem cell therapy in cardiac repair. Given the adult heart's limited regenerative capacity, stem cell-based therapies offer a promising strategy to restore myocardial function following injury. World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 316-321 318 3. Application of Various Stem Cell Types in Cardiac Therapy Given that cardiovascular diseases remain a leading cause of death globally, there is intense interest in developing novel treatment strategies. Among the most promising approaches for heart regeneration is stem cell therapy. This strategy explores the regenerative potential of different stem cell types—mesenchymal stem cells (MSCs), induced pluripotent stem cells (iPSCs), embryonic stem cells (ESCs), and cardiac progenitor cells . Mesenchymal stem cells (MSCs), which are derived from sources such as bone marrow, adipose tissue, and umbilical cord, are known for their strong paracrine signaling and immunomodulatory properties. In cardiac applications, MSCs have been shown to enhance heart function following injury by reducing inflammation, limiting fibrosis, and promoting angiogenesis. Clinical trials have demonstrated that MSC therapy can improve cardiac performance and reduce scar tissue in patients with heart failure. Induced pluripotent stem cells (iPSCs) are adult somatic cells that have been reprogrammed to a pluripotent state. They can differentiate into a variety of cell types, including cardiomyocytes, and offer a patient-specific source for heart regeneration, minimizing the risk of immune rejection. Research has shown that iPSC-derived cardiomyocytes can integrate into damaged heart tissue and restore some functional capacity in models of ischemic heart disease. Embryonic stem cells (ESCs), obtained from the inner cell mass of blastocysts, are capable of differentiating into any cell type, including cardiomyocytes. They provide a consistent and reliable source for cardiac cell production in regenerative medicine. However, their use is limited by ethical considerations and the potential for teratoma formation. Cardiac progenitor cells (CPCs) are resident stem cells found within the heart that can differentiate into various cardiac cell types. These cells are being investigated for their potential role in the heart’s natural repair mechanisms. Earlyphase clinical trials of CPC transplantation have shown modest improvements in cardiac function. Each stem cell type offers distinct advantages and presents unique challenges in cardiac therapy. Ongoing research aims to refine their use, improve their integration into damaged cardiac tissue, and develop advanced delivery methods to maximize therapeutic outcomes. 4. Delivery Method Effectively delivering stem cells to damaged cardiac tissue is a critical factor in the success of regenerative therapies for cardiovascular diseases. Several delivery methods have been explored, each with its own advantages and limitations. Intracoronary infusion involves delivering stem cells through the coronary arteries, usually during catheterization. This method is minimally invasive and allows for widespread distribution of cells in the heart. However, it often suffers from poor cell retention due to washout in blood flow. Intramyocardial injection, in contrast, involves delivering cells directly into the myocardium, either through open-heart surgery or via percutaneous catheter-based systems. This method ensures targeted delivery and higher local cell concentration but is more invasive. Intravenous (IV) administration is the simplest and least invasive method, but it generally results in poor cardiac homing, with many cells being trapped in the lungs or liver. More advanced techniques—such as hydrogel scaffolds, nanoparticle carriers, or magnetic targeting—are being investigated to enhance cell survival and tissue integration. The optimal delivery route often depends on the clinical indication, the type of stem cell used, and the desired therapeutic effect. Streamlining and optimizing delivery strategies remains a key step toward maximizing the efficacy of stem cell-based therapies for cardiac repair. 5. Mechanisms of Action Stem cell therapy for cardiovascular disease operates through several biological mechanisms that support tissue repair and functional recovery. World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 316-321 319 The most prominent mechanism is paracrine signaling, wherein transplanted stem cells release a complex mix of cytokines, growth factors, and extracellular vesicles that modulate the local microenvironment. These bioactive molecules help stimulate angiogenesis, reduce inflammation, and prevent apoptosis (programmed cell death) of native cardiomyocytes. Another important mechanism is immunomodulation. Stem cells, particularly mesenchymal stem cells (MSCs), possess immunosuppressive properties that create an environment favorable to healing by reducing chronic inflammation. They also limit fibrosis, thereby preventing the excessive formation of non-functional scar tissue. In some cases, stem cells—especially induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs)—can directly differentiate into cardiomyocytes, endothelial cells, and vascular smooth muscle cells. These newly formed cells may integrate with host tissue and contribute to functional recovery. Additionally, stem cells may activate resident cardiac progenitor cells, enhancing the heart’s endogenous repair mechanisms. Overall, the therapeutic effects of stem cells rely on a combination of paracrine activity, cellular differentiation, immunomodulation, and tissue interaction. While these mechanisms offer a comprehensive strategy for cardiac repair, many aspects remain under investigation. 6. Challenges and Limitations Despite their promising potential, stem cell therapies for cardiovascular diseases face several challenges that hinder widespread clinical use. One of the primary limitations is the low retention and survival of transplanted cells. The ischemic and inflamed environment of damaged myocardium is hostile, often resulting in the rapid death of a large proportion of introduced cells, which reduces therapeutic efficacy. Another key concern is the risk of immune rejection and tumor formation, especially when using allogeneic or pluripotent stem cells such as ESCs or iPSCs. If not tightly controlled, these cells may form teratomas or differentiate into unintended tissue types. Furthermore, if the transplanted cells fail to electrically integrate with native cardiomyocytes, they can trigger arrhythmias and abnormal heart rhythms. Standardization is also a major barrier. There is no universal consensus on the best cell type, dose, timing, or delivery route, which leads to inconsistent outcomes in clinical trials. Finally, ethical concerns, particularly regarding the use of embryonic stem cells, create additional regulatory and societal hurdles. 7. Conclusion Stem cell therapy represents the leading edge of cardiovascular regenerative medicine, offering a groundbreaking approach for treating diseases that were once considered irreversible. Cardiovascular diseases (CVDs) continue to be the leading cause of death globally, and the heart’s limited regenerative ability, especially following myocardial infarction, has been a persistent problem. While conventional treatments primarily manage symptoms or prevent further deterioration, they do not restore lost tissue. Stem cells, with their unique abilities to self-renew, differentiate, and secrete reparative biofactors, offer a powerful tool to regenerate damaged myocardium and potentially restore cardiac function in the heart. Various types of stem cells, MSCs, iPSCs, ESCs, and CPCs have shown promise in preclinical and clinical settings. Their therapeutic effects stem from paracrine signaling, direct differentiation, immunomodulation, and activation of endogenous repair pathways. However, numerous challenges remain, including low cell survival, poor integration, immune reactions, ethical concerns, and inconsistent clinical results. World Journal of Biology Pharmacy and Health Sciences, 2025, 23(03), 316-321 320 Optimizing delivery strategies is also crucial to therapeutic success. Innovative technologies such as hydrogel scaffolds and targeted nanoparticles offer promising solutions to enhance cell retention and integration. However, these advanced approaches must still be adapted for real-world accessibility, particularly in resource-limited regions, where factors like poor healthcare infrastructure, lack of trained personnel, and limited funding further complicate implementation. Compliance with ethical standards Disclosure of conflict of interest No conflict of interest to be disclosed. References [1] Abouzid MR, Umer AM, Jha SK, Akbar UA, Khraisat O, Saleh A, Mohamed K, Esteghamati S, Kamel I. 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