Bacterial infection remains a great challenge in wound healing, especially in chronic wounds. Multidrug-resistant organisms are increasing in acute and chronic wound infections, which compromise the chance of therapeutics. Resistance to conventional antibiotics has created an urge to study new approach/system that can effectively control wound infection and enhance healing. Wound cover/dressing must exhibit biocompatibility and effectiveness in reducing bioburden at the wound site. Collagen, a natural biopolymer, possesses advantages over synthetic and other natural materials due to its unique biological properties. It can act as an excellent wound dressing and controlled drug delivery system. Currently, antiseptic agents such as silver, iodine, and polyhexamethylene biguanide (PHMB)-incorporated scaffolds have become widely accepted in chronic wound healing. In this study, PHMB-incorporated collagen scaffold has been prepared and characterized using Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD), and differential scanning calorimetry (DSC), which showed retention of collagen nativity and integration of PHMB. The scanning electron microscopy (SEM) analysis revealed the porous structures of scaffolds. The cytotoxicity analysis showed PHMB is nontoxic at the concentration of 0.01% (wt/wt). The agar diffusion test and bacterial adhesion study demonstrated the effectiveness of PHMB-incorporated collagen scaffold against both gram positive and negative strains. This study concludes that PHMB-incorporated collagen scaffold could have the potential for infected wound healing.

Introduction: Use of cardiac mesenchymal cells (CMCs) has been shown to improve cardiac function following myocardial infarction. Main drawback in cardiac cell therapy is the major loss of injected cells within few hours. Increase the retention of these injected cells could increase their efficacy, where cardiac patches with various cell types showed better outcome. Among, collagen patch plays lead role as a cell-laden matrix in cardiac tissue engineering. Creating a detailed understanding of how collagen matrix changes the cellular phenotype could provide seminal insights to regeneration therapy. Hypothesis: Growing CMCs in three dimensional (3D) collagen matrix could alter the expression of extracellular matrix (ECM) and adhesion molecules, which may enhance their efficacy. Methods: The bovine type I collagen was chemically modified and solubilized in culture medium with photo-initiator. The mouse CMCs were isolated and resuspended in collagen solution, printed using 3D bioprinter and UV-crosslinked to form 3D-CMC construct. The 3D-CMC construct was submerged in growth medium and cultured for 48h and analyzed for the expression of ECM and adhesion molecules (n=5/group). CMCs cultured in regular plastic tissue culture dish was used as control. Results: RT profiler array showed changes in the ECM and adhesion molecules expression, specifically certain integrins and matrix metalloproteinases (MMPs) in CMCs cultured 3D collagen construct compared to 2D monolayer. Subsequent qRT-PCR analysis revealed significant (p<0.01) upregulation of integrins such as Itga2 (2.96±0.13), Itgb1 (3.18±0.2) and Itgb3 (2.4±0.27) and MMPs such as MMP13 (37.2±3.36), MMP9 (5.23±1.06) and MMP3 (7.14±2.07). Western blot analysis further confirmed significant elevation of these integrins and matrix metalloproteinases at protein level. Collagen encapsulation did not alter the expression of N-cadherin in CMCs, which is a potential mesenchymal cadherin adhesion molecule. Conclusion: Integrin αβ heterodimers transduce signals that facilitate cell homing, migration, survival and differentiation. Similarly, MMPs plays vital role in cell migration and proliferation. Our results demonstrate that the 3D-collagen Niche enhances the expression of certain integrins and MMPs in CMCs. This suggest that the efficacy of CMCs could be magnified by providing 3D architecture with collagen matrix and further in vivo experiments would reveal functional benefits from CMCs for clinical use.

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Cardiac mesenchymal cells (CMCs) are a promising cell type that showed therapeutic potential in heart failure models. The analysis of the underlying mechanisms by which the CMCs improve cardiac function is on track. This study aimed to investigate the expression of N-Cadherin, a transmembrane protein that enhances cell adhesion, and recently gained attention for differentiation and augmentation of stem cell function. The mouse CMCs were isolated and analyzed for the mesenchymal markers using flow cytometry. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis were used to assess the expression of N-Cadherin along with its counteracting molecule E-Cadherin and their regulator Zeb1 in CMCs and dermal fibroblast. The expression level of miR-200c and miR-429 was analyzed using miRNA assays. Transient transfection of miR-200c followed by qRT-PCR, western blot analysis, and immunostaining was done in CMCs to analyze the expression of Zeb1, N-Cadherin, and E-Cadherin. Flow cytometry analysis showed that CMCs possess mesenchymal markers and absence for hematopoietic and immune cell markers. Increased expression of N-Cadherin and Zeb1 in CMCs was observed in CMCs at both RNA and protein levels compared to fibroblast. We found significant downregulation of miR-200c and miR-429 in CMCs. The ectopic expression of miR-200c in CMCs significantly downregulated Zeb1 and N-Cadherin expression. Our findings suggest that the significant downregulation of miR-200c/ 429 in CMCs maintains the expression of N-Cadherin, which may be important for its functional integrity.

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