Engineering human ventricular heart tissue based on macroporous iron oxide scaffolds

Beyond Tissue replacement: The Emerging role of smart implants in healthcare

Smart implants are increasingly used to treat various diseases, track patient status, and restore tissue and organ function. These devices support internal organs, actively stimulate nerves, and monitor essential functions. With continuous monitoring or stimulation, patient observation quality and subsequent treatment can be improved. Additionally, using biodegradable and entirely excreted implant materials eliminates the need for surgical removal, providing a patient-friendly solution. In this review, we classify smart implants and discuss the latest prototypes, materials, and technologies employed in their creation. Our focus lies in exploring medical devices beyond replacing an organ or tissue and incorporating new functionality through sensors and electronic circuits. We also examine the advantages, opportunities, and challenges of creating implantable devices that preserve all critical functions. By presenting an in-depth overview of the current state-of-the-art smart implants, we shed light on persistent issues and limitations while discussing potential avenues for future advancements in materials used for these devices.

Research trends in cardiovascular tissue engineering from 1992 to 2022: a bibliometric analysis

Background

Cardiovascular tissue engineering (CTE) is a promising technique to treat incurable cardiovascular diseases, such as myocardial infarction and ischemic cardiomyopathy. Plenty of studies related to CTE have been published in the last 30 years. However, an analysis of the research status, trends, and potential directions in this field is still lacking. The present study applies a bibliometric analysis to reveal CTE research trends and potential directions.

Methods

On 5 August 2022, research articles and review papers on CTE were searched from the Web of Science Core Collection with inclusion and exclusion criteria. Publication trends, research directions, and visual maps in this field were obtained using Excel (Microsoft 2009), VOSviewer, and Citespace software.

Results

A total of 2,273 documents from 1992 to 2022 were included in the final analysis. Publications on CTE showed an upward trend from 1992 [number of publications (Np):1] to 2021 (Np:165). The United States (Np: 916, number of citations: 152,377, H-index: 124) contributed the most publications and citations in this field. Research on CTE has a wide distribution of disciplines, led by engineering (Np: 788, number of citations: 40,563, H-index: 105). "Functional maturation" [red cluster, average published year (APY): 2018.63, 30 times], "cell-derived cardiomyocytes" (red cluster, APY: 2018.43, 46 times), "composite scaffolds" (green cluster, APY: 2018.54, 41 times), and "maturation" (red cluster, APY: 2018.17, 84 times) are the main emerging keywords in this area.

Conclusion

Research on CTE is a hot research topic. The United States is a dominant player in CTE research. Interdisciplinary collaboration has played a critical role in the progress of CTE. Studies on functional maturation and the development of novel biologically relevant materials and related applications will be the potential research directions in this field.

Biomaterials-Based Cell Therapy for Myocardial Tissue Regeneration

Cardiovascular diseases (CVDs) have been the leading cause of death worldwide during the past several decades. Cell loss is the main problem that results in cardiac dysfunction and further mortality. Cell therapy aiming to replenish the lost cells is proposed to treat CVDs especially ischemic heart diseases which lead to a big portion of cell loss. Due to the direct injection's low cell retention and survival ratio, cell therapy using biomaterials as cell carriers has attracted more and more attention because of their promotion of cell delivery and maintenance at the aiming sites. In this review, the three main factors involved in cell therapy for myocardial tissue regeneration: cell sources (somatic cells, stem cells, and engineered cells), chemical components of cell carriers (natural materials, synthetic materials, and electroactive materials), and categories of cell delivery materials (patches, microspheres, injectable hydrogels, nanofiber and microneedles, etc.) are systematically summarized. An introduction of the methods including magnetic resonance/radionuclide/photoacoustic and fluorescence imaging for tracking the behavior of transplanted cells in vivo is also included. Current challenges of biomaterials-based cell therapy and their future directions are provided to give both beginners and professionals a clear view of the development and future trends in this area.

Cmarr/miR-540-3p axis promotes cardiomyocyte maturation transition by orchestrating Dtna expression

The immature phenotype of embryonic stem cell-derived cardiomyocytes (ESC-CMs) limits their application. However, the molecular mechanisms of cardiomyocyte maturation remain largely unexplored. This study found that overexpression of long noncoding RNA (lncRNA)-Cmarr, which was highly expressed in cardiomyocytes, promoted the maturation change and physiological maturation of mouse ESC-CMs (mESC-CMs). Moreover, transplantation of cardiac patch overexpressing Cmarr exhibited better retention of mESC-CMs, reduced infarct area by enhancing vascular density in the host heart, and improved cardiac function in mice after myocardial infarction. Mechanism studies identified that Cmarr acted as a competitive endogenous RNA to impede the repression of miR-540-3p on Dtna expression and promoted the binding of the dystrophin-glycoprotein complex (DGC) and yes-associated protein (YAP), which in turn reduced the proportion of nuclear YAP and the expression of YAP target genes. Therefore, this study revealed the function and mechanism of Cmarr in promoting cardiomyocyte maturation and provided a lncRNA that can be used as a functional factor in the construction of cardiac patches for the treatment of myocardial infarction.

SS-31 Modification Inhibits the Proinflammatory Effect on Macrophages Induced by Superparamagnetic Iron Oxide Nanoparticles

Superparamagnetic iron oxide nanoparticles can induce macrophage polarization into the proinflammatory M1-type. This adverse effect is very likely to restrict the applications of superparamagnetic iron oxide nanoparticles in various inflammatory medical conditions. To inhibit the proinflammatory effect, the mitochondrial-targeted antioxidant peptide SS-31 was physically adsorbed on superparamagnetic iron oxide nanoparticles to develop superparamagnetic iron oxide nanoparticles@SS-31. The macrophages (RAW 264.7) were incubated with superparamagnetic iron oxide nanoparticles or superparamagnetic iron oxide nanoparticles@SS-31 at a concentration of 50 μg Fe3O4/mL for 24 hours. Compared to the superparamagnetic iron oxide nanoparticles group, the superparamagnetic iron oxide nanoparticles@SS-31 group demonstrated significantly reduced cell damage, as evidenced by the inhibition of cell viability loss, early cell apoptosis and the production of reactive oxygen species. Moreover, the proinflammatory factor TNF-α and M1-type cell surface markers CD86 and CD80 were significantly downregulated in the superparamagnetic iron oxide nanoparticles@SS-31 group as shown by enzyme-linked immunosorbent assay and flow cytometric analysis. Notably, compared with the superparamagnetic iron oxide nanoparticles group, levels of the anti-inflammatory factors IL-10, TGF-β and the M2-type cell surface marker CD163 were markedly upregulated in the superparamagnetic iron oxide nanoparticles@SS-31 group. In addition, severe disruption of the mitochondrial ultrastructure was observed by transmission electron microscopy in the superparamagnetic iron oxide nanoparticles group, but the superparamagnetic iron oxide nanoparticles@SS-31 group displayed structurally intact mitochondria. All of these results suggest that superparamagnetic iron oxide nanoparticles can promote macrophage M1-type polarization by inducing oxidative stress and mitochondrial damage, while superparamagnetic iron oxide nanoparticles@SS-31 can significantly inhibit superparamagnetic iron oxide nanoparticles-induced toxicity by releasing SS-31 to exert mitochondrial-targeted antioxidant and anti-inflammatory effects, indicating that the strategy of coloading the SS-31 peptide into superparamagnetic iron oxide nanoparticles has the potential to alleviate superparamagnetic iron oxide nanoparticles-induced proinflammatory effects.

3D bioprinted and integrated platforms for cardiac tissue modeling and drug testing

Recent advances in biofabrication techniques, including 3D bioprinting, have allowed for the fabrication of cardiac models that are similar to the human heart in terms of their structure (e.g., volumetric scale and anatomy) and function (e.g., contractile and electrical properties). The importance of developing techniques for assessing the characteristics of 3D cardiac substitutes in real time without damaging their structures has also been emphasized. In particular, the heart has two primary mechanisms for transporting blood through the body: contractility and an electrical system based on intra and extracellular calcium ion exchange. This review introduces recent trends in 3D bioprinted cardiac tissues and the measurement of their structural, contractile, and electrical properties in real time. Cardiac models have also been regarded as alternatives to animal models as drug-testing platforms. Thus, perspectives on the convergence of 3D bioprinted cardiac tissues and their assessment for use in drug development are also presented.

Ferritinophagy and ferroptosis in cardiovascular disease: Mechanisms and potential applications

Ferroptosis is a type of regulated cell death driven by iron dependent accumulation of cellular reactive oxygen species (ROS) when glutathione (GSH)-dependent lipid peroxidation repair systems are compromised. Nuclear receptor co-activator 4 (NCOA4)-mediated selective autophagy of ferritin, termed ferritinophagy, involves the regulation of ferroptosis. Emerging evidence has revealed that ferritinophagy and ferroptosis exert a significant role in the occurrence and development of cardiovascular disease. In the present review, we aimed to present a brief overview of ferritinophagy and ferroptosis focusing on the underlying mechanism and regulations involved. We summarize and discuss relevant research progress on the role of ferritinophagy and ferroptosis in cardiovascular diseases accompanied with potential applications of ferritinophagy and ferroptosis modulators in the treatment of ferroptosis-associated cardiovascular diseases.

Tissue Engineering and Regenerative Medicine: Achievements, Future, and Sustainability in Asia

Exploring innovative solutions to improve the healthcare of the aging and diseased population continues to be a global challenge. Among a number of strategies toward this goal, tissue engineering and regenerative medicine (TERM) has gradually evolved into a promising approach to meet future needs of patients. TERM has recently received increasing attention in Asia, as evidenced by the markedly increased number of researchers, publications, clinical trials, and translational products. This review aims to give a brief overview of TERM development in Asia over the last decade by highlighting some of the important advances in this field and featuring major achievements of representative research groups. The development of novel biomaterials and enabling technologies, identification of new cell sources, and applications of TERM in various tissues are briefly introduced. Finally, the achievement of TERM in Asia, including important publications, representative discoveries, clinical trials, and examples of commercial products will be introduced. Discussion on current limitations and future directions in this hot topic will also be provided.

Inducing Endogenous Cardiac Regeneration: Can Biomaterials Connect the Dots?

Heart failure (HF) after myocardial infarction (MI) due to blockage of coronary arteries is a major public health issue. MI results in massive loss of cardiac muscle due to ischemia. Unfortunately, the adult mammalian myocardium presents a low regenerative potential, leading to two main responses to injury: fibrotic scar formation and hypertrophic remodeling. To date, complete heart transplantation remains the only clinical option to restore heart function. In the last two decades, tissue engineering has emerged as a promising approach to promote cardiac regeneration. Tissue engineering aims to target processes associated with MI, including cardiomyogenesis, modulation of extracellular matrix (ECM) remodeling, and fibrosis. Tissue engineering dogmas suggest the utilization and combination of two key components: bioactive molecules and biomaterials. This chapter will present current therapeutic applications of biomaterials in cardiac regeneration and the challenges still faced ahead. The following biomaterial-based approaches will be discussed: Nano-carriers for cardiac regeneration-inducing biomolecules; corresponding matrices for their controlled release; injectable hydrogels for cell delivery and cardiac patches. The concept of combining cardiac patches with controlled release matrices will be introduced, presenting a promising strategy to promote endogenous cardiac regeneration.

Modulating cardiomyocyte and fibroblast interaction using layer-by-layer deposition facilitates synchronisation of cardiac macro tissues

Maturation and synchronisation of heart cells, including cardiomyocytes and fibroblasts, are essential to develop functional biomimetic cardiac tissues for regenerative medicine and drug discovery. Synchronisation of cells in the biomimetic cardiac tissue requires the structural integrity and functional maturation of cardiomyocytes with other cell types. However, it is challenging to synchronise the beating of macroscale cardiac tissues and induce maturation of cardiomyocytes derived from stem cells. Here, we developed a simple assembly technology to modulate cell-cell interactions by combining layer-by-layer (LBL) deposition and centrifugation of cells with collagen type I to control cell-cell interactions for the preparation of cardiac macro tissues (CMTs). We found that maturation of cardiomyocytes in CMTs was largely enhanced by growth factors FGF-4 and ascorbic acid, but synchronisation of cardiac beating required LBL deposition of cardiomyocytes and cardiac fibroblasts in addition to the growth factors during the maturation process. Our findings have important implications because incorporation of cardiac fibroblasts into the cardiomyocyte layer is a prerequisite for synchronised beating of macroscale cardiac tissues in addition to growth factors to facilitate maturation of stem cell-derived cardiomyocytes.

Functional improvement and maturation of human cardiomyocytes derived from human pluripotent stem cells by barbaloin preconditioning

The development of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is a significant advancement in our ability to obtain cardiomyocytes in vitro for regenerative therapies and drug discovery. However, hPSC-CMs obtained via existing protocols usually exhibit a markedly immature phenotype, compared with adult cardiomyocytes, thereby limiting their application. Here we report that barbaloin preconditioning dramatically improves the morphology, structure-related cardiac gene expression, calcium handling, and electrophysiological properties of hPSC-CMs, which means that barbaloin may have the potential to induce the maturation of hPSC-CMs, providing a novel strategy to generate more adult-like cardiomyocytes and promoting the application of hPSC-CMs in regenerative medicine, drug development, and disease modeling.