Macrophage cell morphology-imprinted substrates can modulate mesenchymal stem cell behaviors and macrophage M1/M2 polarization for wound healing applications.

Mesenchymal stem cells and macrophages (MQ) are two very important cells involved in the normal wound healing process. It is well understood that topological cues and mechanical factors can lead to different responses in stem cells and MQ by influencing their shape, cytoskeleton proliferation, migration, and differentiation, which play an essential role in the success or failure of biomaterial implantation and more importantly wound healing. On the other hand, the polarization of MQ from proinflammatory (M1) to prohealing (M2) phenotypes has a critical role in the acceleration of wound healing. In this study, the morphology of different MQ subtypes (M0, M1, and M2) was imprinted on a silicon surface (polydimethylsiloxane [PDMS]) to prepare a nano-topography cell-imprinted substrate with the ability to induce anti-inflammatory effects on the mouse adipose-derived stem cells (ADSCs) and RAW264.7 monocyte cell line (MO). The gene expression profiles and flow cytometry of MQ revealed that the cell shape microstructure promoted the MQ phenotypes according to the specific shape of each pattern. The ELISA results were in agreement with the gene expression profiles. The ADSCs on the patterned PDMS exhibited remarkably different shapes from no-patterned PDMS. The MOs grown on M2 morphological patterns showed a significant increase in expression and section of anti-inflammatory cytokine compared with M0 and M1 patterns. The ADSCs homing in niches heavily deformed the cytoskeletal, which is probably why the gene expression and phenotype unexpectedly changed. In conclusion, wound dressings with M2 cell morphology-induced surfaces are suggested as excellent anti-inflammatory and antiscarring dressings.

Chitosan-Placental ECM Composite Thermos-Responsive Hydrogel as a Biomimetic Wound Dressing with Angiogenic Property.

Attempts are being made to develop an ideal wound dressing with excellent biomechanical and biological properties. Here, a thermos-responsive hydrogel is fabricated using chitosan (CTS) with various concentrations (1%, 2.5%, and 5% w/v) of solubilized placental extracellular matrix (ECM) and 20% ß-glycerophosphate to optimize a smart wound dressing hydrogel with improved biological behavior. The thermo-responsive CTS (TCTS) alone or loaded with ECMs (ECM-TCTS) demonstrate uniform morphology using SEM. TCTS and ECM1%-TCTS and ECM2.5%-TCTS show a gelation time of 5 min at 37 °C, while no gel formation is observed at 4 and 25 °C. ECM5%-TCTS forms gel at both 25 and 37 °C. The degradation and swelling ratios increase as the ECM content of the hydrogel increase. All the constructs show excellent biocompatibility in vitro and in vivo, however, the hydrogels with a higher concentration of ECM demonstrate better cell adhesion for fibroblast cells and induce expression of angiogenic factors (VEGF and VEGFR) from HUVEC. Only the ECM5%-TCTS has antibacterial activity against Acinetobacter baumannii ATCC 19606. The data obtained from the current study suggest the ECM2.5%-TCTS as an optimized smart biomimetic wound dressing with improved angiogenic properties now promises to proceed with pre-clinical and clinical investigations.

Synergetic dual antibiotics-loaded chitosan/poly (vinyl alcohol) nanofibers with sustained antibacterial delivery for treatment of XDR bacteria-infected wounds.

Resistance of bacterial pathogens to conventional antibiotics has remained a significant challenge in managing post-wound infections, especially in developing countries. Here, a nanofibrous chitosan/poly (vinyl alcohol) (CS/PVA) mat was designed for controlled delivery of three different concentrations of two antibiotics (colistin/meropenem ratio of 32/64 µg/ml (AB1), 64/128 µg/ml (AB2), and 128/256 (AB3) µg/ml) with synergistic antibacterial activity against ATCC and extensively drug-resistant (XDR) Acinetobacter baumannii clinical isolates. The scaffolds showed a uniform fibrous structure with no bead formation with a sustained release of the antibiotics for one week. The elongation at break, wettability, porosity, and average fiber diameter decreased with increased antibiotics concentrations. Young's modulus and tensile strength showed a significant increase after adding antibiotics. All the constructs showed excellent in vitro cytocompatibility for fibroblasts and biocompatibility in an animal model. The antibacterial assays confirmed the dose-dependent antibacterial activity of the CS/PVA. The scaffolds loaded with AB2 and AB3 showed biocidal properties against ATCC, while only CS/PVA/AB3 had antibacterial activity against XDR clinical isolates. This study suggests the CS/PVA/AB3 nanofibrous scaffold contained 128/256 µg/ml colistin/meropenem as an excellent antibacterial wound dressing for protection of skin wounds from XDR clinical isolates and now promises to proceed with pre-clinical investigations.

Anti-inflammatory effect of mesenchymal stem cells on hepatocellular carcinoma in the xenograft mice model.

BACKGROUND: Hepatocellular carcinoma (HCC) is the fifth most diagnosed cancer and the second leading cause of cancer-related deaths worldwide. Sorafenib is the standard treatment used in the advanced stages of HCC. Cell therapy with mesenchymal stem cells (MSCs)-based cell therapy has proven effective in immune regulation and tumour growth inhibition. OBJECTIVES: In this study, we investigated the anti-inflammatory effect of MSCs on HCC xenografts. METHODS: Human HepG2 cell lines were subcutaneously implanted into the flank of 12 nude mice, divided into three groups: the control group, the IV group (intravenous MSCs injection) and the local group (local MSCs injection). Mice were sacrificed 6 weeks after tumour implantation, and tumours were resected entirety. Quantitative real-time polymerase chain reaction (qRT-PCR) measured the gene expression of inflammatory markers, including tumour necrosis factor-α (TNF-α), interleukin (IL)-1α and IL-10. Aspartate transaminase (AST), alanine transaminase (ALT) and urea levels were measured using spectrophotometry to ensure the safety of MSC therapy. RESULTS: Gene expressions for all three inflammatory markers were reduced in both MSCs groups compared to the control group. AST, ALT and urea levels remained in normal ranges. CONCLUSIONS: MSC therapy can reduce inflammation in HCC xenograft mouse models.