Cardiac tissue engineering for myocardial infarction treatment

Role of apoptosis repressor with caspase recruitment domain in human health and chronic diseases

Apoptosis repressor with caspase recruitment domain (ARC) is a highly potent and multifunctional suppressor of various types of programmed cell death (PCD) (e.g. apoptosis, necroptosis, and pyroptosis) and plays a key role in determining cell fate. Under physiological conditions, ARC is predominantly expressed in terminally differentiated cells, such as cardiomyocytes and skeletal muscle cells. Its expression and activity are tightly controlled by a complicated system consisting of transcription factor (TF), non-coding RNA (ncRNA), and post-translational modification (PTM). ARC dysregulation has been shown to be closely associated with many chronic diseases, including cardiovascular disease, cancer, diabetes, and neurodegenerative disease. However, the detailed mechanisms of ARC involved in the progression of these diseases remain unclear to a large extent. In this review, we mainly focus on the regulatory mechanisms of ARC expression and activity and its role in PCD. We also discuss the underlying mechanisms of ARC in health and disease and highlight the potential implications of ARC in the clinical treatment of patients with chronic diseases. This information may assist in developing ARC-based therapeutic strategies for patients with chronic diseases and expand researchers' understanding of ARC.

Polyglycerol Sebacate/polycaprolactone/reduced graphene oxide composite scaffold for myocardial tissue engineering

The aim of this research was to fabricate and evaluate polyglycerol sebacate/polycaprolactone/reduced graphene oxide (PGS-PCL-RGO) composite scaffolds for myocardial tissue engineering. Polyglycerol sebacate polymer was synthesized using glycerol and sebacic acid prepolymers, confirmed by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Six PGS-PCL-RGO composite scaffolds (S1-S6) with various weight ratios were prepared in chloroform (CF) and acetone (Ace) solvents at 8 CF:2Ace and 9 CF:1Ace volume ratios, using the electrospinning method at a rate of 1 ml/h and a voltage of 18 kV. The scaffolds' chemical composition and microstructure were characterized by FTIR, XRD, and scanning electron microscopy (SEM). Further investigations included tensile testing, contact angle testing, four-point probe testing for electrical conductivity, degradation testing, and cytotoxicity testing (MTT). The results showed that adding 2%wt RGO to the composite scaffold decreased fiber diameter and degradation rate, while increasing electrical conductivity and ductility. The 33%PGS-65%PCL-2%RGO (S3) composite scaffold exhibited the lowest degradation rate (23.87 % over 60 days) and the highest electrical conductivity (51E-3 S/m). Mechanical evaluations revealed an elastic modulus of 2.46 MPa and elongation of 62.43 %, aligning closely with the heart muscle's elastomeric properties. The contact angle test indicated that the scaffold was hydrophilic, with a water contact angle of 61 ± 2°. Additionally, the cell toxicity test confirmed that scaffolds containing RGO were non-toxic and supported good cell viability. In conclusion, the 33%PGS-65%PCL-2%RGO composite scaffold exhibits mechanical and structural properties similar to heart tissue, making it an ideal candidate for myocardial tissue engineering.

Cell-cell interactions in the heart: advanced cardiac models and omics technologies

A healthy heart comprises various cell types, including cardiomyocytes, endothelial cells, fibroblasts, immune cells, and among others, which work together to maintain optimal cardiac function. These cells engage in complex communication networks, known as cell-cell interactions (CCIs), which are essential for homeostasis, cardiac structure, and efficient function. However, in the context of cardiac diseases, the heart undergoes damage, leading to alterations in the cellular composition. Such pathological conditions trigger significant changes in CCIs, causing cell rearrangement and the transition between cell types. Studying these interactions can provide valuable insights into cardiac biology and disease mechanisms, enabling the development of new therapeutic strategies. While the development of cardiac organoids and advanced 3D co-culture technologies has revolutionized in vitro studies of CCIs, recent advancements in single-cell and spatial multi-omics technologies provide researchers with powerful and convenient tools to investigate CCIs at unprecedented resolution. This article provides a concise overview of CCIs observed in both normal and injured heart, with an emphasis on the cutting-edge methods used to study these interactions. It highlights recent advancements such as 3D co-culture systems, single-cell and spatial omics technologies, that have enhanced the understanding of CCIs. Additionally, it summarizes the practical applications of CCI research in advancing cardiovascular therapies, offering potential solutions for treating heart disease by targeting intercellular communication.

3D printing and computer-aided design techniques for drug delivery scaffolds in tissue engineering

INTRODUCTION

The challenge in tissue engineering lies in replicating the intricate structure of the native extracellular matrix. Recent advancements in AM, notably 3D printing, offer unprecedented capabilities to tailor scaffolds precisely, controlling properties like structure and bioactivity. CAD tools complement this by facilitating design using patient-specific data.

AREA’S COVERED

This review introduces additive manufacturing (AM) and computer-aided design (CAD) as pivotal tools in advancing tissue engineering, particularly cartilage regeneration. This article explores various materials utilized in AM, focusing on polymers and hydrogels for their advantageous properties in tissue engineering applications. Integrating bioactive molecules, including growth factors, into scaffolds to promote tissue regeneration is discussed alongside strategies involving different cell sources, such as stem cells, to enhance tissue development within scaffold matrices.

EXPERT OPINION

Applications of AM and CAD in addressing specific challenges like osteochondral defects and osteoarthritis in cartilage tissue engineering are highlighted. This review consolidates current research findings, offering expert insights into the evolving landscape of AM and CAD technologies in advancing tissue engineering, particularly in cartilage regeneration.

WTAP-MEDIATED M6A MODIFICATION OF KLF6 AGGRAVATES HYPOXIA/REOXYGENATION-INDUCED HUMAN CARDIOMYOCYTE INJURY

ABSTRACT

Background: Myocardial infarction (MI) is a severe condition that typically results from the ischemia and necrosis of heart muscle. Kruppel-like factor 6 (KLF6) can aggravate myocardial ischemia/reperfusion injury. This work aims to reveal its role and mechanism in hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury. Methods: Human cardiomyocyte (AC16) was exposed to hypoxic treatment to mimic MI-like cell injury. mRNA expression levels of KLF6 and WT1-associated protein (WTAP) were detected by quantitative real-time polymerase chain reaction. Protein expression was detected by western blotting assay. Cell viability was assessed by CCK-8 assay. Cell apoptosis and cell cycle were investigated by flow cytometry. Enzyme-linked immunosorbent assays were conducted to detect IL-1β, TNF-α and IL-6 levels. Fe 2+ colorimetric assay kit was used to detect Fe 2+ level. MDA Content Assay Kit was used to detect MDA level. Cellular ROS Assay kit was applied to assess ROS level. The association of KLF6 and WTAP was identified by RNA immunoprecipitation assay and dual-luciferase reporter assay. Results: KLF6 and WTAP expression at mRNA and protein levels were significantly upregulated in serum samples of MI patients and H/R-induced AC16 cells when compared with control groups. KLF6 silencing attenuated H/R-induced AC16 cell apoptosis, inflammatory response, oxidative stress, and ferroptosis. Additionally, WTAP stabilized KLF6 mRNA by regulating its m6A modification. Furthermore, WTAP knockdown rescued H/R-induced AC16 cell apoptosis, inflammatory response, oxidative stress, and ferroptosis by decreasing KLF6 expression. Conclusion: WTAP-mediated m6A modification of KLF6 aggravated hypoxia/reoxygenation-induced apoptosis, inflammatory response, oxidative stress, and ferroptosis of human cardiomyocytes, providing a therapeutic strategy for MI.

Photocrosslinkable microgels derived from human platelet lysates: injectable biomaterials for cardiac cell culture

Cardiovascular diseases are a major global cause of morbidity and mortality, and they are often characterized by cardiomyocytes dead that ultimately leads to myocardial ischemia (MI). This condition replaces functional cardiac tissue with fibrotic scar tissue compromising heart function. Injectable systems for the in situ delivery of cells or molecules to assist during tissue repair have emerged as promising approaches for tissue engineering, particularly for myocardial repair. Methacryloyl platelet lysates (PLMA) have been employed for constructing full human-based 3D cell culture matrices and demonstrated potential for xeno-free applications. In this study, we propose using PLMA to produce microparticles (MPs) serving as anchors for cardiac and endothelial cells and ultimately as injectable systems for cardiac tissue repair. The herein reported PLMA MPs were produced by droplet microfluidics and showed great properties for cell attachment. More importantly, it is possible to show the capacity of PLMA MPs to serve as cell microcarriers even in the absence of animal-derived serum supplementation in the culture media.

Research and application of hydrogel-encapsulated mesenchymal stem cells in the treatment of myocardial infarction

Myocardial infarction (MI) stands out as a highly lethal disease that poses a significant threat to global health. Worldwide, heart failure resulting from MI remains a leading cause of human mortality. Mesenchymal stem cell (MSC) therapy has emerged as a promising therapeutic approach, leveraging its intrinsic healing properties. Nevertheless, pervasive issues, including a low cell retention rate, suboptimal survival rate, and incomplete differentiation of MSCs, present formidable challenges for further research. The introduction and advancement of biomaterials have offered a novel avenue for the exploration of MSC therapy in MI, marking considerable progress thus far. Notably, hydrogels, among the representative biomaterials, have garnered extensive attention within the biomedical field. This review delves into recent advancements, specifically focusing on the application of hydrogels to augment MSC therapy for cardiac tissue regeneration in MI.

Platelet membrane-derived biomimetic microbubbles with enhanced targeting ability for the early detection of myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a widely recognized cardiovascular disease that significantly impacts the prognosis of patients undergoing myocardial infarction recanalization. This condition can be fatal and involves complex pathophysiological mechanisms. Early diagnosis of MIRI is crucial to minimize myocardial damage and reducing mortality. Based on the inherent relationship between platelets and MIRI, we developed biomimetic microbubbles coated with platelet membrane (MB-pla) for early identification of MIRI. The MB-pla were prepared through a recombination process involving platelet membrane obtained from rat whole blood and phospholipids, blended in appropriate proportions. By coating the microbubbles with platelet membrane, MB-pla acquired various adhesion molecules, thereby gaining the capability to selectively adhere to damaged endothelial cells in the context of MIRI. In vitro experiments demonstrated that MB-pla exhibited remarkable targeting characteristics, particularly toward type IV collagen and human umbilical vein endothelial cells that had been injured through hypoxia/reoxygenation procedures. In a rat model of MIRI, the signal intensity produced by MB-pla was notably higher than that of control microbubbles. These findings were consistent with results obtained from fluorescence imaging of isolated hearts and immunofluorescence staining of tissue sections. In conclusion, MB-pla has great potential as a non-invasive early detection method for MIRI. Furthermore, this approach can potentially find application in other conditions involving endothelial injury in the future.

Evaluation of Tyrosine Kinase Inhibitors Loaded Injectable Hydrogels for Improving Connexin43 Gap Junction Intercellular Communication

Myocardial infarction (MI) is one of the leading causes of death in the developed world, and the loss of cardiomyocytes plays a critical role in the pathogenesis of heart failure. Implicated in this process is a decrease in gap junction intercellular communication due to remodeling of Connexin43 (Cx43). We previously identified that intraperitoneal injection of the Pyk2 inhibitor PF4618433 reduced infarct size, maintained Cx43 at the intercalated disc in left ventricle hypertrophic myocytes, and improved cardiac function in an MI animal model of heart failure. With the emergence of injectable hydrogels as a therapeutic toward the regeneration of cardiac tissue after MI, here, we provide proof of concept that the release of tyrosine kinase inhibitors from hydrogels could have beneficial effects on cardiomyocytes. We developed an injectable hydrogel consisting of thiolated hyaluronic acid and P123-maleimide micelles that can incorporate PF4618433 as well as the Src inhibitor Saracatinib and achieved sustained release (of note, Src activates Pyk2). Using neonatal rat ventricular myocytes in the presence of a phorbol ester, endothelin-1, or phenylephrine to stimulate cardiac hypertrophy, the release of PF4618433 from the hydrogel had the same ability to decrease Cx43 tyrosine phosphorylation and maintain Cx43 localization at the plasma membrane as when directly added to the growth media. Additional beneficial effects included decreases in apoptosis, the hypertrophic marker atrial natriuretic peptide (ANP), and serine kinases upregulated in hypertrophy. Finally, the presence of both PF4618433 and Saracatinib further decreased the level of ANP and apoptosis than each inhibitor alone, suggesting that a combinatorial approach may be most beneficial. These findings provide the groundwork to test if tyrosine kinase inhibitor release from hydrogels will have a beneficial effect in an animal model of MI-induced heart failure.