Cardiovascular disease is still one of the leading causes of death in the world, and heart transplantation is the current major treatment for end-stage cardiovascular diseases. However, because of the shortage of heart donors, new sources of cardiac regenerative medicine are greatly needed. The prominent development of tissue engineering using bioactive materials has creatively laid a direct promising foundation. Whereas, how to precisely pattern a cardiac structure with complete biological function still requires technological breakthroughs. Recently, the emerging three-dimensional (3D) bioprinting technology for tissue engineering has shown great advantages in generating micro-scale cardiac tissues, which has established its impressive potential as a novel foundation for cardiovascular regeneration. Whether 3D bioprinted hearts can replace traditional heart transplantation as a novel strategy for treating cardiovascular diseases in the future is a frontier issue. In this review article, we emphasize the current knowledge and future perspectives regarding available bioinks, bioprinting strategies and the latest outcome progress in cardiac 3D bioprinting to move this promising medical approach towards potential clinical implementation.

Damaged skin cannot prevent harmful bacteria from invading tissues, causing infected wounds or even severe tissue damage. In this study, we developed a controlled-release antibacterial composite hydrogel system that can promote wound angiogenesis and inhibit inflammation by sustained releasing Cu-Epigallocatechin-3-gallate (Cu-EGCG) nano-capsules. The prepared SilMA/HAMA/Cu-EGCG hydrogel showed an obvious inhibitory effect on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). It could also promote the proliferation and migration of L929 fibroblasts. In vivo full-thickness infected wound healing experiments confirmed the angiogenesis and inflammation regulating effect. Accelerate collagen deposition and wound healing speed were also observed in the SilMA/HAMA/Cu-EGCG hydrogel treated group. The findings of this study show the great potential of this controlled-release antibacterial composite hydrogel in the application of chronic wound healing.

Cardiovascular diseases (CVD) are a significant cause of human health harm. In the past, stem cell therapy was reported to have functional defects, such as immune rejection, tumorigenicity, and infusion toxicity. Exosomes are extracellular vesicles with lipid bilayer membrane structure, containing proteins, lipids, mRNA, miRNA, DNA, and other molecules, which can mediate various biological functions such as immune response, inflammatory response, cell migration, and differentiation intercellular communication. Exosomal miRNAs have outstanding advantages in disease diagnosis and curative effect prediction. Likewise, paracrine factors could also mediate the main therapeutic effect of mesenchymal stem cells. Research has shown that mesenchymal stem cell-derived micro-exosomes, which may come from stem cells, accumulate in the ischemic tissue and regulate cell proliferation, apoptosis, inflammation, and angiogenesis sites of myocardial injury after being transplanted. This review reviewed the molecular mechanisms of exosomes and internal microRNAs derived from mesenchymal stem cells in cardiac ischemic injury repair.

Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) have an irreplaceable role in the treatment of myocardial infarction (MI), which can be injected into the transplanted area with new cardiomyocytes (Cardiomyocytes, CMs), and improve myocardial function. However, the immaturity of the structure and function of iPSC-CMs is the main bottleneck at present. Since collagen participates in the formation of extracellular matrix (ECM), we synthesized nano colloidal gelatin (Gel) with collagen as the main component, and confirmed that the biomaterial has good biocompatibility and is suitable for cellular in vitro growth. Subsequently, we combined the PI3K/AKT/mTOR pathway inhibitor BEZ-235 with Gel and found that the two combined increased the sarcomere length and action potential amplitude (APA) of iPSC-CMs, and improved the Ca²⁺ processing ability, the maturation of mitochondrial morphological structure and metabolic function. Not only that, Gel can also prolong the retention rate of iPSC-CMs in the myocardium and increase the expression of Cx43 and angiogenesis in the transplanted area of mature iPSC-CMs, which also provides a reliable basis for the subsequent treatment of mature iPSC-CMs.

Two of the main problems of stem cell and regenerative medicine are the exit of pluripotency and differentiation to functional cells or tissues. The answer to these two problems holds great value in the clinical translation of stem cell as well as regenerative medicine research. Although piling researches have revealed the truth about pluripotency maintenance, the mechanisms underlying pluripotent cell self-renewal, proliferation, and differentiation into specific cell lineages or tissues are yet to be defined. To this end, we took full advantage of a novel technology, namely, the genome-scale CRISPR-Cas9 knockout (GeCKO). As an effective way of introducing targeted loss-of-function mutations at specific sites in the genome, GeCKO is able to screen in an unbiased manner for key genes that promote exit from pluripotency in mouse embryonic stem cells (mESCs) for the first time. In this study, we successfully established a model based on GeCKO to screen the key genes in pluripotency withdrawal. Our strategies included lentiviral package and infection technology, lenti-Cas9 gene knockout technology, shRNA gene knockdown technology, next-generation sequencing, model-based analysis of genome-scale CRISPR-Cas9 knockout (MAGeCK analysis), GO analysis, and other methods. Our findings provide a novel approach for large-scale screening of genes involved in pluripotency exit and offer an entry point for cell fate regulation research.