Chitosan-Based Scaffolds for the Treatment of Myocardial Infarction: A Systematic Review

Figure 3. (A) Chemical structure of chitosan. (B) Synthetic methods commonly used for functionalizing chitosan in tissue engineering: alkylation [121], O-alkylation [115], N-acetylation [115], phosphorylation [122] and crosslinking [123]. Reactive functional groups of chitosan: Magenta box, hydroxyl at C-6. Cyan box, C-3 hydroxyl. Red circle, primary amine at C-2. Abbreviations: rGO = reduced graphene oxide, TAC = tannic acid, PVA = polyvinyl alcohol, ECH = epichlorohydrin, HOAc = acetic acid.

Figure 1. PRISMA 2020 methodology [36] was used to search for the information.

Figure 2. Graphic representation of myocardial infarction; (a) non-transmural and transmural myocardial infarction, (b) the formation of the infarcted tissue in the heart after an ischemic process. (1) Cell death in the first hours of infarction. (2) Cytokine release and degradation of the necrotic cells by macrophages. (3) Muscle fibrosis processes due to a high protein content in the infarcted area and dysfunctional cell degradation. (4) Final fabric. Abbreviations: ECM, extracellular matrix; BMs, biomarkers; CMs, cardiomyocytes; NSTEMI, non-T-segment elevation myocardial infarction; STEMI, T-segment elevation myocardial infarction; EGC, electrocardiogram [38,44].

Figure 4. (A) Elaboration of the scaffold, constituents and uses. (B) Possible mechanism of cellular regeneration and differentiation of the cardiomyocytes. The chitosan scaffold allows for the transfer of exogenous cells to the damaged tissue. In the process, the scaffold surface mechanically stimulates the VEGFRs. Simultaneously, the VEGFR can be electrically stimulated by natural electrical stimuli from the heart or external sources due to the functionalization of chitosan with the other electro-conductive polymers (represented in the figure as R). This electrical stimulation helps the release of the VEGF, the differentiation of the stem cells to the native cardiomyocytes or the differentiation to the endothelial cells in the angiogenesis processes, improving the hemodynamic processes of the heart, cell replacement and ventricular thickening of the heart. Abbreviations, NHAc = acetylated amino group, NHR = functionalized amino group.