Cardiovascular diseases remain a major clinical challenge, as existing therapeutic interventions, such as pharmacological agents, cardiac implants, or surgical procedures, offer limited efficacy due to the heart’s inherently low regenerative...

Small-scale siRNA screen reveals WWC2 as a novel regulator of cardiomyocyte mitosis.

Rodents models of myocardial infarction (MI) continue to be frequently used in preclinical cardiovascular research, despite alternative approaches being on the rise. The commonly used coronary artery permanent ligation (PL) approach is often hampered by substantial perioperative mortality and variable success rates. We optimized the rat PL protocol by relying exclusively on isoflurane inhalation anesthesia by introducing a standardized intubation setup, maintaining strict control of body temperature throughout surgery, and surgical technique refinements. The latter included gentle mobilization of the Pectoralis major and thymus, a medial thoracotomy through the third intercostal space, and the use of a reference ligature to facilitate reliable identification and ligation of the left anterior descending coronary artery (LAD). Cardiac rhythm was continuously monitored, and extubation was carefully timed to reduce complications. With this protocol, perioperative mortality was reduced to zero and successful ligation was obtained in 94% of animals (n = 172). Echocardiography and histology confirmed consistent induction of infarcts. By lowering invasiveness and improving survival and reproducibility, the refined PL method enhances both the reliability of preclinical research and compliance with the 3Rs, representing a meaningful step forward for studies in cardiac regeneration.

Promoting cardiomyocyte proliferation is a highly promising strategy to repair the damaged myocardium and treat myocardial infarction (MI). DNA damage is a key factor leading to cell cycle arrest in cardiomyocytes, and DNA repair is required to relieve the restriction of proliferation. However, the potential of natural small-molecule compounds to enhance DNA repair and proliferation in cardiomyocytes has not been fully explored. Through screening of natural products, we found imperatorin could stimulate cardiomyocyte DNA repair and proliferation both in vitro and in vivo, which resulted in a significant improvement in cardiac function. By virtual prediction of pharmacological targets, we found that the target protein of imperatorin was the DNA repair protein tyrosyl-DNA phosphodiesterase 1 (TDP1). In terms of mechanism, imperatorin enhanced the phosphorylation of TDP1 at serine 81 by facilitating the proximity-mediated interaction between TDP1 and DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Collectively, these findings suggest that imperatorin is a promising lead for the development of cardiac regeneration agents, and TDP1 is a hitherto unrecognized potential therapeutic target for MI treatment.

Ischemic cardiac injury, arising due to myocardial infarction (MI), ischemia-reperfusion injury (IRI), and other ischemia-associated forms of cardiac damage, remains a major clinical challenge. The irreversible loss of cardiomyocytes from within the myocardium, together with oxidative stress and inflammation, creates a complex post-MI milieu that is not readily addressed by existing therapeutic strategies. Cardiac tissue engineering solutions that combine advanced biomaterials with either stem cell-derived cardiovascular cells, their derivatives (such as extracellular vesicles and exosomes), or other bioactive compounds (including chemokines and cytokines) are being developed to repair and regenerate the infarcted human heart. This review highlights the state-of-the-art strategies that utilize cutting-edge technologies to develop tissue-inducing biomaterial solutions for cardiac regeneration and repair, with particular emphasis on (i) integrating biomaterials with cells in strategies undergoing clinical investigation, (ii) incorporating cellular derivatives into biomaterial scaffolds, and (iii) designing and evaluating intrinsically functional biomaterials. This review aims to provide both a theoretical foundation and future perspectives for the innovation and optimization of next-generation tissue-inducing biomaterial-based strategies for cardiac tissue regeneration and repair.

Mammalian cardiac development and homeostasis rely on tightly coordinated transcriptional programs driven by core cardiogenic transcription factors. Among these, GATA binding protein 4 (GATA4) plays a pivotal role-not only in orchestrating embryonic heart formation, but also in modulating cardiac adaptation to physiological and pathological stress. To fulfil its canonical functions, emerging evidence reveals that GATA4 activity is shaped by a multilayered regulatory network involving chromatin dynamics, transcriptional and post-transcriptional inputs, and diverse post-translational modifications. In this review, we provide an integrated overview of the roles of GATA4 across developmental stages, postnatal physiology, and disease contexts. We further examine how chromatin occupancy and regulatory mechanisms fine-tune GATA4 function and evaluate current strategies that leverage GATA4 modulation for cardiac repair and regeneration. By highlighting both established and underexplored facets of GATA4 biology, this review establishes GATA4 as a central regulator of cardiac identity and plasticity, with broad implications for developmental biology, cardiac physiology, and therapeutic innovation.

Ginsenoside Rd promotes cardiac regeneration through PPARG/HMGCS2-driven ketone body metabolic reprogramming in myocardial ischemia-reperfusion injury.

Cardiovascular diseases (CVDs) remain the leading cause of death worldwide, responsible for about 17.9 million deaths annually. Induced pluripotent stem cells (iPSCs) offer a patient-specific and ethically acceptable source for cardiac regeneration. Early applications using two-dimensional cultures or direct cell injection showed feasibility but were limited by poor retention and immaturity. Biomaterial-based approaches now provide supportive environments that enhance cell survival, alignment, and integration. iPSC - biomaterial platforms combining scaffolds, hydrogels, and engineered matrices have improved tissue organization and functional performance. However, persistent challenges such as incomplete maturation, arrhythmogenic risk, high production costs, and regulatory hurdles remain. Future progress will depend on integrating advanced biomaterials, gene editing, artificial intelligence, and scalable GMP-compliant manufacturing. By bridging stem cell biology and materials science, iPSC - biomaterial systems represent a promising path toward clinically viable cardiac regeneration.

Cardiovascular diseases (CVDs), particularly myocardial infarction (MI), cause irreversible cardiomyocyte loss and scar formation, severely compromising cardiac function. Despite advances in cardiovascular care, cardiac tissue regeneration remains a significant clinical challenge due to the limited self-repair capacity of the heart. Traditional approaches face obstacles, including inadequate cellular preservation, poor integration with native tissue, and inadequate vascularization. With the advent of tissue engineering and the integration of biomaterial-based approaches, significant progress has been made in regenerating native cardiac tissue and advancing clinical goals. This review explores the potential of UV-curable hydrogels as a novel platform for cardiac tissue engineering, emphasizing their tunable properties and minimally invasive delivery potential. These hydrogels can be rapidly injected in situ by UV irradiation, providing precise control over the degradation rate, mechanical properties, and drug/cell release. Furthermore, incorporating bioactive molecules and growth factors into the hydrogel matrix can enhance cell survival, proliferation, and differentiation and promote angiogenesis and functional tissue formation. This review describes design considerations for UV-curable hydrogels, including biomaterial selection, crosslinking strategies, and incorporation of therapeutic agents, while highlighting recent advances in their application for cardiac repair. Particularly, after a comprehensive review of cardiac tissue, we address the major challenges that hinder effective cardiac regeneration and demonstrate how UV-curable hydrogels can overcome these limitations. Indeed, this article aims to provide an overview of the current state of the art, emphasizing the promise of UV-curable hydrogels as a powerful tool to advance cardiac regeneration and improve patient outcomes.

Myocardial infarction (MI) is a leading cause of death worldwide and can eliminate up to a third of the cardiomyocytes within the human heart. Although cardiomyocytes undergo mitosis during early development, most cardiomyocytes cease cell cycling soon after birth. In contrast, rodent MI models have shown that cardiomyocytes increase mitosis in response to ischemia; however, this has not been shown in humans. Using a unique premortem post-MI human heart, immunostaining, bulk RNA sequencing, proteomics, metabolomics, single-nucleus RNA sequencing and a novel post-MI human biopsy method, we investigated human cardiomyocyte mitosis post-MI. We show that adult human cardiomyocytes exhibit increased mitosis and cytokinesis in response to ischemia. Future development of therapeutics to enhance this intrinsic mitotic potential could lead to new treatments that reverse heart failure via cardiac regeneration.

Integration of nanoscale technologies into cardiac tissue engineering significantly advances strategies for enhancing the maturation and functional performance of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). However, despite their significant potential, hiPSC-CMs exhibit structural and functional immaturity that limits their therapeutic application. Nanoscale engineered scaffolds offer precise control over the cellular microenvironment, providing biophysical cues through topographical features that significantly influence cell alignment, differentiation, and maturation. Among these, ultra-tiny nanoscale engineering approaches have emerged as a transformative strategy to more accurately replicate the microenvironmental cues essential for hiPSC-CMs maturation. Therefore, this review aims to examine recent advancements in nanoscale technologies, focusing on promoting the structural and functional maturation of hiPSC-CMs to mimic native myocardial microenvironment. It explores the role of various nanostructures and nanobridge scaffolds in enhancing microenvironmental mimicry and delivering biophysical stimulation including mechanical and electrical cues to address persistent challenges associated with hiPSC-CMs immaturity. Additionally, this review emphasizes the application of nanotechnology assisted hiPSC-CMs models in advancing cardiac tissue regeneration, drug screening and toxicity assessment, and disease modeling. Finally, it evaluates the commercialization potential and current limitations of nanoengineered cardiac regeneration platforms, focusing on scalability, integration, and physiological relevance to assess their transformative effect for cardiac regenerative medicine.

The development of regenerative strategies to repair the heart is of high importance. Our lab has shown that extracellular matrix derived from decellularized fetal myocardium promotes neonatal cardiomyocyte proliferation in vitro. The goal of this study was to identify specific peptide(s)/protein(s) in solubilized cardiac ECM responsible for this proliferative effect. We hypothesized that isolation and then treatment with one or more small synthetic peptide derived from this source could replicate the cellular response to whole solubilized ECM. Decellularized fetal and adult rat hearts were fractionated by molecular weight using SDS-PAGE and transferred to PVDF membranes. Analysis of cardiomyocytes cultured on the membranes revealed regions of enhanced cardiomyocyte proliferation. Subsequent isolation and proteomic analysis of the protein bands that that correlated with proliferative regions identified fibrillin-1 as the predominant ECM protein associated with these regions of cardiomyocyte proliferation. One region (residues 55–86) of fibrillin-1 was synthesized as a peptide and tested for a direct effect on cardiomyocyte proliferation. Compared to positive and negative controls, as well as scrambled and alkylated versions, this peptide led to 3–4 fold increase in cardiomyocyte proliferation. Analysis of the amino acid sequence demonstrated high homology with laent-TGF-β binding proteins and subsequent experiments showed that the matrikine could also reduce TGF-β induced activation of cardiac fibroblasts. These data suggest that individual peptides derived from soluble ECM could have utility as a novel therapeutic for cardiac tissue engineering and regeneration.

Declined donor organs and explanted recipient organs may hold considerable value for biomedical research, particularly in advancing knowledge of disease mechanisms and supporting drug development. However, public perceptions of such use, and preferences for how consent should be obtained, remain underexplored. Four workshops were held across the UK to examine the views of organ donor families and transplant recipients regarding the use of human organs in research, with a focus on myocardial regeneration. Each workshop included three brief presentations on transplantation and cardiac regeneration, followed by facilitated small-group discussions. Observational notes were taken to capture participants' perspectives on the use of organs unsuitable for transplantation. A follow-up survey generated both quantitative and qualitative data, the latter analysed using thematic analysis. Participants expressed strong support for the use of declined donor and explanted recipient organs in research. Transplant recipients frequently cited a desire to give back to the National Health Service (NHS), while donor families viewed research use as a meaningful way to honour their loved ones when transplantation was not possible. This exploratory study highlights widespread support for using non-transplantable organs in research among individuals with personal experience of transplantation. The findings suggest a need for further research into how best to support and inform potential donors and families. Participants emphasised the importance of sensitive communication, clear consent processes and transparency regarding the use of donated organs.

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, with limited cardiac regeneration hindering recovery in damaged hearts. We previously demonstrated that T-box transcription factor 20 (Tbx20) and bone morphogenetic protein 2 (Bmp2) are crucial for cardiac homeostasis by promoting cardiomyocyte proliferation following endoplasmic reticulum (ER) stress. Here we showed that various stressors (ER stress, diabetes, type2 myocardial infarction, high-fat diet) over shorter and longer durations in vivo lead to distinct expression patterns of Tbx20 and Bmp2 in cardiomyocytes and fibroblasts. In vitro, stress induction resulted in similar expression patterns of Tbx20 and Bmp2, initially increasing in H9c2 cardiomyocytes before showing a sharp decline. In contrast, Bmp2 significantly increased in primary rat adult cardiac fibroblasts during increasing stress. MicroRNAs (miRNAs) are pleiotropic regulators of cardiac development and disease, and are promising therapeutic interventions for regulating cardiac regeneration. Upon delineating the cause of the differential regulation, in silico analysis revealed the presence of putative miR-101-3p binding site in the 3'UTR of tbx20 and Bmp2 inhibitor noggin (nog) gene, which was corroborated by dual-luciferase reporter assay. The expression of miR-101-3p was elevated upon prolonged stress across all the cardiac injury models. In vitro, increasing stress resulted in increased expression of miR-101-3p. MiR-101-3p agonist suppressed and antagonist elevated the expression of Tbx20 in H9c2 cardiomyocytes. Ectopic overexpression of miR-101-3p or siRNA-mediated knockdown of Tbx20 in H9c2 cardiomyocytes heightened the expression of senescence markers (p21, p16, γH2AX). Furthermore, miR-101-3p targeted Nog under stress, indirectly raising Bmp2 and inflammatory response (TNF-α and IL6) in primary cardiac fibroblasts, thereby exacerbating cardiomyopathy. Inhibition of miR-101-3p reversed its inhibitory effect on Tbx20 and Nog. This study uncovers a novel regulatory mechanism where miR-101-3p acts as a repressor of cardiac genes to induce cardiac senescence and inflammation, positioning miR-101-3p as a therapeutic target for cardiomyopathy.

Mitsugumin 53 improves myocardial ischemia-reperfusion injury by promoting iPSCs survival through regulating AnxA6 axis.

Molecular basis and key biological processes for myocardial regeneration: Transcriptomic analysis of acute myocardial infarction in a translational ovine model.

Guinea pigs have been a standard model in cardiovascular pharmacology and physiology research, but the advent of transgenic models has largely replaced them with mouse and rat models. However, guinea pigs remain important models in cardiac electrophysiology, drug-induced arrhythmias, or atherosclerosis research, and they have recently gained importance for studying one specific research question, that is, transplantation of pluripotent stem cell derived cardiomyocytes to repair the cryo-injured heart. Their human-like cardiac electrophysiology, together with their small size that facilitates handling and housing, make guinea pigs a valuable experimental model for these studies. However, repeated open heart surgeries in guinea pigs are technically demanding and accompanied by high mortality. In this study, we retrospectively examined sequential protocol modifications and describe how protocol refinements led to improved survival rates. Cryo-injury was performed in female Dunkin-Hartley guinea pigs under general anesthesia with a liquid nitrogen-cooled probe via a lateral thoracotomy. Cells were transplanted during a second surgery 7 days later. We analyzed data from up to 558 animals to determine mortality rates and morphologic and functional parameters. Initial studies revealed a mortality rate of ∼50%. Sequential modifications led to a significant reduction, with the refined protocol achieving a perioperative mortality rate of ∼30%. The procedures were completed in <35 minutes, and survival rates for the observation period (up to 8 weeks) were 70%. Scar size was evaluated in 144 (4 weeks, n = 92; 8 weeks, n = 52) animals and showed a significant, but shallow correlation with echocardiographically determined heart function. Taken together, refined surgery protocols allow safe and reproducible cryo-injury with subsequent cell injections in guinea pigs with an improved mortality rate.

Injury-induced Clusterin+ cardiomyocytes suppress inflammation and promote regeneration in neonatal and adult hearts by reprogramming macrophages.

Cardiovascular diseases (CVDs) remain a leading global cause of mortality, necessitating novel therapeutic strategies to address myocardial injury, adverse remodelling and impaired cardiomyocyte regeneration. Exosomes, nanoscale extracellular vesicles secreted by nearly all cell types, have emerged as pivotal mediators of intercellular communication, influencing cardiac physiology and pathology through their cargo of nucleic acids, proteins and lipids. These vesicles participate actively in processes such as cytoprotection, angiogenesis, apoptosis regulation and immune modulation, which are critical for cardiac repair and regeneration. Recent preclinical and clinical studies highlight the promising regenerative capabilities of exosomes, especially those derived from stem cells and immune cells, positioning them as innovative therapeutic tools and diagnostic biomarkers in CVD management. Despite their potential advantages over traditional cell therapies, including lower immunogenicity and enhanced targeting, several hurdles remain before exosomes can be routinely applied in clinical practice. Challenges include the lack of standardized isolation and characterization protocols, heterogeneity of exosome populations, inefficient cargo loading methods, off-target biodistribution and safety concerns related to immune response and infectious risk. Ongoing research aims to overcome these obstacles to realize exosomes' full potential in cardiovascular regenerative medicine, with diagnostic applications currently representing a nearer-term goal.

Mast cells in cardiovascular disease: Fibrosis, angiogenesis and atherogenesis.