Regulation of inflammation during wound healing: the function of mesenchymal stem cells and strategies for therapeutic enhancement

Dexketoprofen-Loaded Alginate-Grafted Poly(N-vinylcaprolactam)-Based Hydrogel for Wound Healing

All acute and chronic wound management strategies have limitations. Therefore, there is an urgent need to develop new treatment options for wound healing. Hydrogels based on natural polymers offer advantages in wound management because they can reduce patients' pain, fight infection, and carry targeted drugs to speed up the healing process. In this study, we aimed to develop and investigate an alginate-grafted N-vinylcaprolactam-based matrix for a modified release of dexketoprofen (DEX), which is potentially useful in wound healing. Free radical polymerization and grafted techniques were used to prepare thermo-responsive hydrogels. The obtained hydrogels, unloaded hydrogel (HY) and dexketoprofen-loaded hydrogel (DEXHY), were characterized and analyzed. The concentration of DEX encapsulated in the polymer matrix was 4 mg/mL. The IC50 values found for the samples tested by us were 607.4 µg/mL for HY, 950.4 µg/mL for DEXHY, and 2239 µg/mL for DEX. The average value of cell viability (%) after the exposure of cells to DEXHY hydrogel was 75.4%. DEXHY exhibited a very good in vitro wound closure rate, given its ability to modify DEX release kinetics. The hydrogel developed in this study has shown considerable potential to facilitate and even accelerate wound healing, including surgical wounds, by inhibiting the overexpressed inflammation process.

Application of Gelatin/Vanillin/Fe3+/AGP-AgNPs Hydrogels Promotes Wound Contraction, Enhances Dermal Growth Factor Expression, and Minimizes Skin Irritation

This study further investigates the potential of gelatin-based hydrogel cross-linked with vanillin and ferric ion (GVF), combined with andrographolide (AGP) and silver nanoparticles (AgNPs), as an anti-infection biomaterial for wound dressing, aimed at exploring the mechanisms that attenuate inflammation, enhance wound healing rates, and address allergic skin irritation. AGP-AgNPs were evaluated for cytotoxicity in human adult epidermal keratinocytes (HEKa) and the murine macrophage cell line (RAW 264.7), as well as for nitric oxide (NO) production in response to lipopolysaccharide-induced inflammation in RAW 264.7 macrophage cells. Skin-wound specimens from male Wistar rats were histologically analyzed for epidermal thickness and inflammatory changes. The mRNA expression profiling of dermal growth factors was assessed using RT-qPCR, and skin irritation tests were conducted in female New Zealand rabbits. These AGP-AgNPs exhibited significantly lower toxicity in HEKa and no toxicity in RAW 264.7. Interestingly, AGP-AgNPs at specific concentrations produced NO in RAW 264.7 control cells but were more effective in reducing inflammatory NO levels in RAW 264.7 cells pretreated with lipopolysaccharides, suggesting that AGP-AgNP composites are safe and effectively diminish inflammation. Furthermore, a marked increase in epidermal thickness and a reduction in histological inflammatory cells at wound sites were observed in rats treated with AGP-AgNPs/GVF hydrogels over 21 days. Upregulation of dermal genes promoting wound healing, including collagen types I and III, epidermal growth factor, transforming growth factor-beta, fibronectin, and vascular endothelial growth factor, but not fibroblast growth factor, was observed in a time-dependent manner. These results suggest that the anti-inflammatory properties of GVF/AGP-AgNP hydrogels could promote epithelialization, enhance cellular proliferation, support extracellular matrix synthesis, and facilitate angiogenesis. Additionally, rabbit skin in contact with GVF/AGP-AgNP hydrogels consistently displayed reduced levels of erythema and edema, with no swelling, and a standardized scoring system yielded low primary dermal irritation indices for this hydrogel. These findings suggest that the novel GVF/AGP-AgNP hydrogels possess anti-inflammatory-like activity and can modulate dermal growth factors for wound healing. This leads to reduced dermal irritation, making the formulation potentially suitable for safe topical applications in skin and wound care. However, comprehensive human studies and clinical trials should be required in the future.

Preclinical study of engineering MSCs promoting diabetic wound healing and other inflammatory diseases through M2 polarization

BACKGROUND

Diabetic foot ulcer (DFU) represents a common and severe complication of diabetes mellitus. Effective and safe treatments need to be developed. Mesenchymal stem cells (MSCs) have demonstrated crucial roles in tissue regeneration, wound repair and inflammation regulation. However, the function is limited. The safety and efficacy of gene-modified MSCs is unknown. Therefore, this study aimed to investigate whether genetically modified MSCs with highly efficient expression of anti-inflammatory factors promote diabetic wound repair by regulating macrophage phenotype transition. This may provide a new approach to treating diabetic wound healing.

METHODS

In this study, human umbilical cord-derived MSCs (hUMSCs) were genetically modified using recombinant lentiviral vectors to simultaneously overexpress three anti-inflammatory factors, interleukin (IL)-4, IL-10, IL-13 (MSCs-3IL). Cell counting kit-8, flow cytometry and differentiation assay were used to detect the criteria of MSCs. Overexpression efficiency was evaluated using flow cytometry, quantitative real-time PCR, Western blot, enzyme-linked immunosorbent assay, and cell scratch assay. We also assessed MSCs-3IL's ability to modulate Raw264.7 macrophage phenotype using flow cytometry and quantitative real-time PCR. In addition, we evaluated diabetic wound healing through healing rate calculation, HE staining, Masson staining, and immunohistochemical analysis of PCNA, F4/80, CD31, CD86, CD206, IL-4, IL-10 and IL-13. In addition, we evaluated the safety of the MSCs-3IL cells and the effect of the cells on several other models of inflammation.

RESULTS

MSCs-3IL efficiently expressed high levels of IL-4 and IL-10 (mRNA transcription increased by 15,000-fold and 800,000-fold, protein secretion 400 and 200 ng/mL), and IL-13 (mRNA transcription increased by 950,000-fold, protein secretion 6 ng/mL). MSCs-3IL effectively induced phenotypic polarization of pro-inflammatory M1-like macrophages (M1) towards anti-inflammatory M2-like macrophages (M2). The enhancement of function does not change the cell phenotype. The dynamic distribution in vivo was normal and no karyotype variation and tumor risk was observed. In a mouse diabetic wound model, MSCs-3IL promoted diabetic wound healing with a wound closure rate exceeding 96% after 14 days of cell treatment. The healing process was aided by altering macrophage phenotype (reduced CD86 and increased CD206 expression) and accelerating re-epithelialization.

CONCLUSIONS

In summary, our study demonstrates that genetically modified hUMSCs effectively overexpressed three key anti-inflammatory factors (IL-4, IL-10, IL-13). MSCs-3IL-based therapy enhances diabetic wound healing with high efficiency and safety. This suggests that genetically modified hUMSCs could be used as a novel therapeutic approach for DFU repair.

Therapeutic potential of mesenchymal stem cells for fungal infections: mechanisms, applications, and challenges

As a particularly serious condition in immunocompromised patients, fungal infections (FIs) have increasingly become a public health problem worldwide. Mesenchymal stem cells (MSCs), characterized by multilineage differentiation potential and immunomodulatory properties, are considered an emerging strategy for the treatment of FIs. In this study, the therapeutic potential of MSCs for FIs was reviewed, including their roles played by secreting antimicrobial peptides, regulating immune responses, and promoting tissue repair. Meanwhile, the status of research on MSCs in FIs and the controversies were also discussed. However, the application of MSCs still faces numerous challenges, such as the heterogeneity of cell sources, long-term safety, and feasibility of large-scale production. By analyzing the latest study results, this review intends to offer theoretical support for the application of MSCs in FI treatment and further research.

Nanotherapeutic and Nano-Bio Interface for Regeneration and Healing

Wound and injury healing processes are intricate and multifaceted, involving a sequence of events from coagulation to scar tissue formation. Effective wound management is crucial for achieving favorable clinical outcomes. Understanding the cellular and molecular mechanisms underlying wound healing, inflammation, and regeneration is essential for developing innovative therapeutics. This review explored the interplay of cellular and molecular processes contributing to wound healing, focusing on inflammation, innervation, angiogenesis, and the role of cell surface adhesion molecules. Additionally, it delved into the significance of calcium signaling in skeletal muscle regeneration and its implications for regenerative medicine. Furthermore, the therapeutic targeting of cellular senescence for long-term wound healing was discussed. The integration of cutting-edge technologies, such as quantitative imaging and computational modeling, has revolutionized the current approach of wound healing dynamics. The review also highlighted the role of nanotechnology in tissue engineering and regenerative medicine, particularly in the development of nanomaterials and nano-bio tools for promoting wound regeneration. Moreover, emerging nano-bio interfaces facilitate the efficient transport of biomolecules crucial for regeneration. Overall, this review provided insights into the cellular and molecular mechanisms of wound healing and regeneration, emphasizing the significance of interdisciplinary approaches and innovative technologies in advancing regenerative therapies. Through harnessing the potential of nanoparticles, bio-mimetic matrices, and scaffolds, regenerative medicine offers promising avenues for restoring damaged tissues with unparalleled precision and efficacy. This pursuit marks a significant departure from traditional approaches, offering promising avenues for addressing longstanding challenges in cellular and tissue repair, thereby significantly contributing to the advancement of regenerative medicine.

Beyond antibiotics: mesenchymal stem cells and bacteriophages-new approaches to combat bacterial resistance in wound infections

Wound management is a major global health problem. With the rising incidence of diabetic wounds, accidents, and other injuries, the demand for prompt wound treatment has become increasingly critical. Millions of people suffer from serious, large wounds resulting from major accidents, surgeries, and wars. These wounds require considerable time to heal and are susceptible to infection. Furthermore, chronic wounds, particularly in elderly and diabetic patients, often require frequent medical interventions to prevent complications. Consequently, wound management imposes a significant economic burden worldwide. The complications arising from wound infections can vary from localized issues to systemic effects. The most severe local complication of wound infection is the non-healing, which results from the disruption of the wound-healing process. This often leads to significant pain, discomfort, and psychological trauma for the patient. Systemic complications may include cellulitis, osteomyelitis, and septicemia. Mesenchymal stem cells are characterized by their high capacity for division, making them suitable candidates for the treatment of tissue damage. Additionally, they produce antimicrobial peptides and various cytokines, which enhance their antimicrobial activity. Evidence shows that phages are effective in treating wound-related infections, and phage therapy has proven to be highly effective for patients when administered correctly. The purpose of this article is to explore the use of bacteriophages and mesenchymal stem cells in wound healing and infection management.

Macrophage Polarization: A Novel Target and Strategy for Pathological Scarring

BACKGROUND

Abnormal scarring imposes considerable challenges and burdens on the lives of patients and healthcare system. Macrophages at the wound site are found to be of great concern to overall wound healing. There have been many studies indicating an inextricably link between dysfunctional macrophages and fibrotic scars. Macrophages are not only related to pathogen destruction and phagocytosis of apoptotic cells, but also involved in angiogenesis, keratinization and collagen deposition. These abundant cell functions are attributed to specific heterogeneity and plasticity of macrophages, which also add an extra layer of complexity to correlational researches.

METHODS

This article summarizes current understanding of macrophage polarization in scar formation and several prevention and treatment strategies on pathological scarring related to regulation of macrophage behaviors by utilizing databases such as PubMed, Google Scholar and so on.

RESULTS

There are many studies proving that macrophages participate in the course of wound healing by converting their predominant phenotype. The potential of macrophages in managing hypertrophic scars and keloid lesions have been underscored.

CONCLUSION

Macrophage polarization offers new prevention strategies for pathological scarring. Learning about and targeting at macrophages may be helpful in achieving optimum wound healing.

Skin Telocytes Could Fundament the Cellular Mechanisms of Wound Healing in Platelet-Rich Plasma Administration

For more than 40 years, autologous platelet concentrates have been used in clinical medicine. Since the first formula used, namely platelet-rich plasma (PRP), other platelet concentrates have been experimented with, including platelet-rich fibrin and concentrated growth factor. Platelet concentrates have three standard characteristics: they act as scaffolds, they serve as a source of growth factors and cytokines, and they contain live cells. PRP has become extensively used in regenerative medicine for the successful treatment of a variety of clinical (non-)dermatological conditions like alopecies, acne scars, skin burns, skin ulcers, muscle, cartilage, and bone repair, and as an adjuvant in post-surgery wound healing, with obvious benefits in terms of functionality and aesthetic recovery of affected tissues/organs. These indications were well documented, and a large amount of evidence has already been published supporting the efficacy of this method. The primordial principle behind minimally invasive PRP treatments is the usage of the patient's own platelets. The benefits of the autologous transplantation of thrombocytes are significant, representing a fast and economic method that requires only basic equipment and training, and it is biocompatible, thus being a low risk for the patient (infection and immunological reactions can be virtually disregarded). Usually, the structural benefits of applying PRP are attributed to fibroblasts only, as they are considered the most numerous cell population within the interstitium. However, this apparent simplistic explanation is still eluding those different types of interstitial cells (distinct from fibroblasts) that are residing within stromal tissue, e.g., telocytes (TCs). Moreover, dermal TCs have an already documented potential in angiogenesis (extra-cutaneous, but also within skin), and their implication in skin recovery in a few dermatological conditions was attested and described ultrastructurally and immunophenotypically. Interestingly, PRP biochemically consists of a series of growth factors, cytokines, and other molecules, to which TCs have also proven to have a positive expression. Thus, it is attractive to hypothesize and to document any tissular collaboration between cutaneous administered PRP and local dermal TCs in skin recovery/repair/regeneration. Therefore, TCs could be perceived as the missing link necessary to provide a solid explanation of the good results achieved by administering PRP in skin-repairing processes.

Mesenchymal Stem Cell-Conditioned Media Modulate HUVEC Response to H2O2: Impact on Gene Expression and Potential for Atherosclerosis Intervention

Background: We studied the potential of human bone marrow-derived mesenchymal stem cell conditioned media (hBMSC CM) in protecting endothelial cell properties (viability, proliferation, and migrations) from the deleterious effects produced by the inflammatory environment of H2O2. Additionally, we investigated their impact on the endothelial cells' gene expression of some inflammatory-related genes, namely, TGF-β1, FOS, ATF3, RAF-1, and SMAD3. Methods: Human umbilical vein endothelial cells (HUVECs) were cultured individually under three conditions: alone, with varying concentrations of H2O2, or with varying concentrations of H2O2 and hBMSC CM. HUVEC adhesion, proliferation, and migration were evaluated using the xCELLigence system. The HUVECs' gene expressions were evaluated by real-time polymerase chain reaction (RT-PCR). Results: Generally, we observed enhanced HUVEC viability, proliferation, and migration when cultured in media supplemented with H2O2 and hBMSC CM. Furthermore, the CM modulated the expressions of the studied inflammatory-related genes in HUVECs, promoting a more robust cellular response. Conclusion: This study has illuminated the protective role of hBMSC CM in mitigating the damaging effects of H2O2 on endothelial cell function. Our data demonstrate that hBMSC CM enhances the viability, proliferation, and migration of HUVECs even under oxidative stress conditions. Additionally, the conditioned medium was found to modulate the gene expression of pivotal markers related to inflammation, suggesting a favorable influence on cellular response mechanisms.

Chitosan nanoparticles of new chromone-based sulfonamide derivatives as effective anti-microbial matrix for wound healing acceleration

A new series of chromone and furochromone-based sulfonamide Schiff's base derivatives 3-12 were synthesized and evaluated for their antimicrobial activity against S. aureus, E. coli, C. albicans, and A. niger using agar diffusion method. Compound 3a demonstrated potent antimicrobial activities with MIC values of 9.76 and 19.53 μg/mL against S. aureus, E. coli and C. albicans, which is 2-fold and 4-fold more potent than neomycin (MIC = 19.53, 39.06 μg/mL respectively). To improve the effectiveness of 3a, it was encapsulated into chitosan nanoparticles (CS-3aNPs). The CS-3aNPs size was 32.01 nm, as observed by transmission electron microscope (TEM) images and the zeta potential value was 14.1 ± 3.07 mV. Encapsulation efficiency (EE) and loading capacity (LC) were 91.5 % and 1.6 %, respectively as indicated by spectral analysis. The CS-3aNPs extremely inhibited bacterial growth utilizing the colony-forming units (CFU). The ability of CS-3aNPs to protect skin wounds was evaluated in vivo. CS-3aNPs showed complete wound re-epithelialization, hyperplasia of the epidermis, well-organized granulation tissue formation, and reduced signs of wound infection, as seen through histological assessment which showed minimal inflammatory cells in comparison with untreated wound. Overall, these findings suggest that CS-3aNPs has a positive impact on protecting skin wounds from infection due to their antimicrobial activity.

F127-SE-tLAP thermosensitive hydrogel alleviates bleomycin-induced skin fibrosis via TGF-β/Smad pathway

BACKGROUND

Skin fibrosis affects the normal function of the skin. TGF-β1 is a key cytokine that affects organ fibrosis. The latency-associated peptide (LAP) is essential for TGF-β1 activation. We previously constructed and prepared truncated LAP (tLAP), and confirmed that tLAP inhibited liver fibrosis by affecting TGF-β1. SPACE peptide has both transdermal and transmembrane functions. SPACE promotes the delivery of macromolecules through the stratum corneum into the dermis. This study aimed to alleviate skin fibrosis through the delivery of tLAP by SPACE.

METHODS

The SPACE-tLAP (SE-tLAP) recombinant plasmid was constructed. SE-tLAP was purified by nickel affinity chromatography. The effects of SE-tLAP on the proliferation, migration, and expression of fibrosis-related and inflammatory factors were evaluated in TGF-β1-induced NIH-3T3 cells. F127-SE-tLAP hydrogel was constructed by using F127 as a carrier to load SE-tLAP polypeptide. The degradation, drug release, and biocompatibility of F127-SE-tLAP were evaluated. Bleomycin was used to induce skin fibrosis in mice. HE, Masson, and immunohistochemistry were used to observe the skin histological characteristics.

RESULTS

SE-tLAP inhibited the proliferation, migration, and expression of fibrosis-related and inflammatory factors in NIH-3T3 cells. F127-SE-tLAP significantly reduced ECM production, collagen deposition, and fibrotic pathological changes, thereby alleviating skin fibrosis.

CONCLUSION

F127-SE-tLAP could increase the transdermal delivery of LAP, reduce the production and deposition of ECM, inhibit the formation of dermal collagen fibers, and alleviate the progression of skin fibrosis. It may provide a new idea for the therapy of skin fibrosis.