Regenerative Approaches to Post-Myocardial Infarction Heart Failure

Conductive single-wall carbon nanotubes/extracellular matrix hybrid hydrogels promote the lineage-specific development of seeding cells for tissue repair through reconstructing an integrin-dependent niche

Background

The niche of tissue development in vivo involves the growth matrix, biophysical cues and cell-cell interactions. Although natural extracellular matrixes may provide good supporting for seeding cells in vitro, it is evitable to destroy biophysical cues during decellularization. Reconstructing the bioactivities of extracellular matrix-based scaffolds is essential for their usage in tissue repair.

Results

In the study, a hybrid hydrogel was developed by incorporating single-wall carbon nanotubes (SWCNTs) into heart-derived extracellular matrixes. Interestingly, insoluble SWCNTs were well dispersed in hybrid hydrogel solution via the interaction with extracellular matrix proteins. Importantly, an augmented integrin-dependent niche was reconstructed in the hybrid hydrogel, which could work like biophysical cues to activate integrin-related pathway of seeding cells. As supporting scaffolds in vitro, the hybrid hydrogels were observed to significantly promote seeding cell adhesion, differentiation, as well as structural and functional development towards mature cardiac tissues. As injectable carrier scaffolds in vivo, the hybrid hydrogels were then used to delivery stem cells for myocardial repair in rats. Similarly, significantly enhanced cardiac differentiation and maturation(12.5 ± 2.3% VS 32.8 ± 5%) of stem cells were detected in vivo, resulting in improved myocardial regeneration and repair.

Conclusions

The study represented a simple and powerful approach for exploring bioactive scaffold to promote stem cell-based tissue repair.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00993-3.

Photoluminescent functionalized carbon quantum dots loaded electroactive Silk fibroin/PLA nanofibrous bioactive scaffolds for cardiac tissue engineering

Tissue engineering and stem cell rehabilitation are the hopeful aspects that are being investigated for the management of Myocardial Infarction (MI); cardiac patches have been used to start myocardial rejuvenation. In this study, we engineered p-phenylenediamine surface functionalized (modif-CQD) into the Silk fibroin/PLA (SF/PLA) nanofibrous bioactive scaffolds with improved physico-chemical abilities, mechanical and cytocompatibility to cardiomyocytes. The micrograph results visualized the morphological improved spherical modif-CQD have been equivalently spread throughout the SF/PLA bioactive cardiac scaffolds. The fabricated CQD@SF/PLA nanofibrous bioactive scaffolds were highly porous with fully consistent pores; effectively improved young modulus and swelling asset for the suitability and effective implantation efficacy. The scaffolds were prepared with rat cardiomyocytes and cultured for up to 7 days, without electrical incentive. After 7 days of culture, the scaffold pores all over the construct volume were overflowing with cardiomyocytes. The metabolic activity and viability of the cardiomyocytes in CQD@SF/PLA scaffolds were significantly higher than cardiomyocytes in Silk fibroin /PLA scaffolds. The integration of CQD also influenced greatly and increases the expression of cardiac-marker genes. The results of the present investigations evidently recommended that well-organized cardiac nanofibrous scaffold with greater cardiac related mechanical abilities and biocompatibilities for cardiac tissue engineering and nursing care applications.

Systemic and Cardiac Depletion of M2 Macrophage through CSF-1R Signaling Inhibition Alters Cardiac Function Post Myocardial Infarction

The heart hosts tissue resident macrophages which are capable of modulating cardiac inflammation and function by multiple mechanisms. At present, the consequences of phenotypic diversity in macrophages in the heart are incompletely understood. The contribution of cardiac M2-polarized macrophages to the resolution of inflammation and repair response following myocardial infarction remains to be fully defined. In this study, the role of M2 macrophages was investigated utilising a specific CSF-1 receptor signalling inhibition strategy to achieve their depletion. In mice, oral administration of GW2580, a CSF-1R kinase inhibitor, induced significant decreases in Gr1^lo and F4/80^hi monocyte populations in the circulation and the spleen. GW2580 administration also induced a significant depletion of M2 macrophages in the heart after 1 week treatment as well as a reduction of cardiac arginase1 and CD206 gene expression indicative of M2 macrophage activity. In a murine myocardial infarction model, reduced M2 macrophage content was associated with increased M1-related gene expression (IL-6 and IL-1β), and decreased M2-related gene expression (Arginase1 and CD206) in the heart of GW2580-treated animals versus vehicle-treated controls. M2 depletion was also associated with a loss in left ventricular contractile function, infarct enlargement, decreased collagen staining and increased inflammatory cell infiltration into the infarct zone, specifically neutrophils and M1 macrophages. Taken together, these data indicate that CSF-1R signalling is critical for maintaining cardiac tissue resident M2-polarized macrophage population, which is required for the resolution of inflammation post myocardial infarction and, in turn, for preservation of ventricular function.

Agonists of epoxyeicosatrienoic acids reduce infarct size and ameliorate cardiac dysfunction via activation of HO-1 and Wnt1 canonical pathway

Myocardial infarction (MI) is complicated by ventricular fibrosis and associated diastolic and systolic failure. Emerging studies implicate Wnt1 signaling in the formation of new blood vessels. Epoxyeicosatrienoic acids (EETs)-mediated up-regulation of heme oxygenase-1 (HO-1) protects against the detrimental consequences of MI in several animal models, however, the mechanism(s) by which this occurs remains unclear. The aim of this study was to examine these mechanisms in the LAD ligation animal model of post infarcted heart failure. Specifically, we sought to clarify the mechanistic basis of the interactions of the Wnt1 canonical pathway, HO-1 and associated angiogenesis. Human microvascular endothelial cells (HMECs) were exposed to anoxia and treated with the EET agonist, NUDSA, in the presence and absence of tin mesoporphyrin (SnMP). Increased capillary density, and Wnt1 and HO-1 expression occurred in cells treated with NUDSA. Anoxic HMECs treated with NUDSA and Wnt1 siRNA, exhibited decreased in the expression of β-catenin and the Wnt1 target gene, PPARδ (p<0.05 vs. NUDSA). Furthermore, blocking the Wnt 1 antagonist, Dickkopf 1, by siRNA increased β-catenin and PPARδ expression, and this effect was further enhanced by the concurrent administration of NUDSA. In in vivo experiments, C57B16 mice were divided into 4 groups: sham, mice with MI via LAD ligation and mice with MI treated with NUDSA, with and without SnMP. Increased fractional area change (FAC) and myocardial angiogenesis were observed in mice treated with NUDSA (p<0.05 vs. MI). Increased expression of HO-1, Wnt1, β-catenin, adiponectin, and phospho-endothelial nitric oxide synthetase (p-eNOS), and a decrease in the glycosylated subunit of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, gp91(phox) expression occurred in cardiac tissue of mice treated with NUDSA (p<0.05 vs. MI). SnMP reversed these effects. This novel study demonstrates that increasing the canonical Wnt1 signaling cascade with the subsequent increase in HO-1, adiponectin and angiogenesis ameliorates fibrosis and cardiac dysfunction in a mouse model of MI and supports the hypothesis that HO-1 is an integral component of the EETs-adiponectin axis and is central for the control of resistance to fibrosis and vascular dysfunction and in part determine how they influence the cellular/vascular homeostasis and provides insight into the mechanisms involved in vascular dysfunction as well as potential targets for the treatment of CVD.