Enhancement of tracheal cartilage regeneration by local controlled release of stromal cell-derived factor 1α with gelatin hydrogels and systemic administration of high-mobility group box 1 peptide.

Introduction: This present study evaluated the effect of combination therapy with stromal cell-derived factor 1α (SDF-1α) and high-mobility group box 1 (HMGB1) peptide on the regeneration of tracheal injury in a rat model. Methods: To improve this effect, SDF-1α was incorporated into a gelatin hydrogel, which was then applied to the damaged tracheal cartilage of rats for local release. Furthermore, HMGB1 peptide was repeatedly administered intravenously. Regeneration of damaged tracheal cartilage was evaluated in terms of cell recruitment. Results: Mesenchymal stem cells (MSC) with C-X-C motif chemokine receptor 4 (CXCR4) were mobilized more into the injured area, and consequently the fastest tracheal cartilage regeneration was observed in the combination therapy group eight weeks after injury. Conclusions: The present study demonstrated that combination therapy with gelatin hydrogel incorporating SDF-1α and HMGB1 peptide injected intravenously can enhance the recruitment of CXCR4-positive MSC, promoting the regeneration of damaged tracheal cartilage.

Bioactive gelatin-sheets as novel biopapers to support prevascularization organized by laser-assisted bioprinting for bone tissue engineering.

Despite significant advances in the management of patients with oral cancer, maxillofacial reconstruction after ablative surgery remains a clinical challenge. In bone tissue engineering, biofabrication strategies have been proposed as promising alternatives to solve issues associated with current therapies and to produce bone substitutes that mimic both the structure and function of native bone. Among them, laser-assisted bioprinting (LAB) has emerged as a relevant biofabrication method to print living cells and biomaterials with micrometric resolution onto a receiving substrate, also called 'biopaper'. Recent studies have demonstrated the benefits of prevascularization using LAB to promote vascularization and bone regeneration, but mechanical and biological optimization of the biopaper are needed. The aim of this study was to apply gelatin-sheet fabrication process to the development of a novel biopaper able to support prevascularization organized by LAB for bone tissue engineering applications. Gelatin-based sheets incorporating bioactive glasses (BGs) were produced using various freezing methods and crosslinking (CL) parameters. The different formulations were characterized in terms of microstructural, physical, mechanical, and biological properties in monoculture and coculture. Based on multi-criteria analysis, a rank scoring method was used to identify the most relevant formulations. The selected biopaper underwent additional characterization regarding its ability to support mineralization and vasculogenesis, its bioactivity potential andin vivodegradability. The biopaper 'Gel5wt% BG1wt%-slow freezing-CL160 °C 24 h' was selected as the best candidate, due to its suitable properties including high porosity (91.69 ± 1.55%), swelling ratio (91.61 ± 0.60%), Young modulus (3.97 × 104± 0.97 × 104Pa) but also its great cytocompatibility, osteogenesis and bioactivity properties. The preorganization of human umbilical vein endothelial cell using LAB onto this new biopaper led to the formation of microvascular networks. This biopaper was also shown to be compatible with 3D-molding and 3D-stacking strategies. This work allowed the development of a novel biopaper adapted to LAB with great potential for vascularized bone biofabrication.

Potential of gelatin hydrogel nonwoven fabrics (Genocel) as a skin substitute in a diabetic mouse skin defect model.

Background: Gelatin hydrogel nonwoven fabrics (Genocel) are three-dimensional gelatin scaffolds that provide cells with space for proliferation, migration, and differentiation. They are expected to be an effective wound healing modality to treat intractable wounds, such as diabetic foot ulcers, because they enhance early neovascularization when used as a skin substitute. In this study, we explored the healing process of Genocel applied to skin defects in diabetic mice and compared it with that of a conventional skin substitute, Pelnac. Methods: Genocel and Pelnac sheets were used to treat skin defects on the backs of diabetic mice. On days 7 and 14, the remaining wound area was evaluated and specimens were harvested for HE, Azan, anti-CD31, CD68, and CD163 staining to assess neoepithelialization, granulation tissue formation, capillary formation, and macrophage infiltration. Results: Wounds treated with Genocel showed a wound healing process comparable to that of wounds treated with Pelnac. No significant differences were observed in the remaining wound area, neoepithelial length, granulation formation, number of pan-macrophages, or M2 ratio on days 7 and 14. The only significant difference was the number of induced M2 macrophages, which was higher in Pelnac group than in the Genocel group on day 7 (p < 0.05). Conclusions: Genocel showed similar healing effects in diabetic wounds as Pelnac and is considered an effective wound management modality for diabetic ulcers.

A Gelatin Hydrogel Nonwoven Fabric Combined With Adipose Tissue-Derived Stem Cells Enhances Subcutaneous Islet Engraftment.

Subcutaneous islet transplantation is a promising treatment for severe diabetes; however, poor engraftment hinders its prevalence. We previously revealed that a gelatin hydrogel nonwoven fabric (GHNF) markedly improved subcutaneous islet engraftment. We herein investigated whether the addition of adipose tissue-derived stem cells (ADSCs) to GHNF affected the outcome. A silicone spacer sandwiched between two GHNFs with (AG group) or without (GHNF group) ADSCs, or a silicone spacer alone (Silicone group) was implanted into the subcutaneous space of healthy mice at 6 weeks before transplantation, then diabetes was induced 7 days before transplantation. Syngeneic islets were transplanted into the pretreated space. Intraportal transplantation (IPO group) was also performed to compare the transplant efficiency. Blood glucose, intraperitoneal glucose tolerance, immunohistochemistry, and inflammatory mediators were evaluated. The results in the subcutaneous transplantation were compared using the Silicone group as a control. The results of the IPO group were also compared with those of the AG group. The AG group showed significantly better blood glucose changes than the Silicone and the IPO groups. The cure rate of AG group (72.7%) was the highest among the groups (GHNF; 40.0%, IPO; 40.0%, Silicone; 0%). The number of vWF-positive vessels in the subcutaneous space of the AG group was significantly higher than that in other groups before transplantation (P < 0.01). Lectin angiography also showed that the same results (P < 0.05). According to the results of the ADSCs tracing, ADSCs did not exist at the transplant site (6 weeks after implantation). The positive rates for laminin and collagen III constructed around the transplanted islets did not differ among groups. Inflammatory mediators were higher in the Silicone group, followed by the AG and GHNF groups. Pretreatment using bioabsorbable scaffolds combined with ADSCs enhanced neovascularization in subcutaneous space, and subcutaneous islet transplantation using GHNF with ADSCs was superior to intraportal islet transplantation.

Isolation of plant-derived exosome-like nanoparticles (PDENs) from Solanum nigrum L. berries and Their Effect on interleukin-6 expression as a potential anti-inflammatory agent.

Inflammation is a temporary response of the immune system that can be treated using common anti-inflammatory drugs. However, prolonged use of these drugs increases the risk of adverse side effects. Accordingly, there is an increasing need for alternative treatments for inflammation with fewer side effects. Exosomes are extracellular vesicles secreted by most eukaryotic cells and have been studied as a candidate for cell-free therapy for inflammatory diseases due to their immunomodulatory and anti-inflammatory properties. In recent years, the focus of exosome research has shifted from animal cell-derived exosomes to plant-derived exosome-like nanoparticles (PDENs). Plant-derived exosome-like nanoparticles (PDENs) are easier to obtain, have minimal safety concerns, and can be produced in higher quantities and lower cost than exosomes derived from animal cells. In this study, the isolation and analysis of the anti-inflammatory potential of PDENs from black nightshade berries (Solanum nigrum L.) were carried out. The results of isolation and characterization showed that PDENs had a spherical morphology, measuring around 107 nm with zeta potential of -0.6 mV, and had a protein concentration of 275.38 µg/mL. PDENs were also shown to be internalized by RAW264.7 macrophage cell line after 2 hours of incubation and had no cytotoxicity effect up to the concentration of 2.5 µg/mL. Furthermore, exposure to several doses of PDENs to the LPS-stimulated RAW264.7 cell significantly decreased the expression of pro-inflammatory cytokine gene IL-6, as well as the expression of IL-6 protein up to 97,28%. GC-MS analysis showed the presence of neral, a monoterpene compound with known anti-inflammatory properties, which may contribute to the anti-inflammatory activity of PDENs isolated from Solanum nigrum L. berries. Taken together, the present study was the first to isolate and characterize PDENs from Solanum nigrum L. berries. The results of this study also demonstrated the anti-inflammatory activity of PDEN by suppressing the production of IL-6 in LPS-stimulated RAW264.7 cells.

Identification of the growth cone as a probe and driver of neuronal migration in the injured brain.

Axonal growth cones mediate axonal guidance and growth regulation. We show that migrating neurons in mice possess a growth cone at the tip of their leading process, similar to that of axons, in terms of the cytoskeletal dynamics and functional responsivity through protein tyrosine phosphatase receptor type sigma (PTPσ). Migrating-neuron growth cones respond to chondroitin sulfate (CS) through PTPσ and collapse, which leads to inhibition of neuronal migration. In the presence of CS, the growth cones can revert to their extended morphology when their leading filopodia interact with heparan sulfate (HS), thus re-enabling neuronal migration. Implantation of an HS-containing biomaterial in the CS-rich injured cortex promotes the extension of the growth cone and improve the migration and regeneration of neurons, thereby enabling functional recovery. Thus, the growth cone of migrating neurons is responsive to extracellular environments and acts as a primary regulator of neuronal migration.

Effect of Bioactive Glasses and Basic Fibroblast Growth Factor on Dental Pulp Cells.

Ideal regeneration of hard tissue and dental pulp has been reported with the use of a combination of bioactive glass and basic fibroblast growth factor (bFGF). However, no previous study has investigated the molecular mechanisms underlying the processes induced by this combination in dental pulp cells. This study aimed to examine the cellular phenotype and transcriptional changes induced by the combination of bioactive glass solution (BG) and bFGF in dental pulp cells using phase-contrast microscopy, a cell counting kit-8 assay, alkaline phosphatase staining, and RNA sequence analysis. bFGF induced elongation of the cell process and increased the number of cells. Whereas BG did not increase ALP activity, it induced extracellular matrix-related genes in the dental pulp. In addition, the combination of BG and bFGF induces gliogenesis-related genes in the nervous system. This is to say, bFGF increased the viability of dental pulp cells, bioactive glass induced odontogenesis, and a dual stimulation with bioactive glass and bFGF induced the wound healing of the nerve system in the dental pulp. Taken together, bioactive glass and bFGF may be useful for the regeneration of the dentin-pulp complex.

A Gelatin Hydrogel Nonwoven Fabric Enhances Subcutaneous Islet Engraftment in Rats.

Although subcutaneous islet transplantation has many advantages, the subcutaneous space is poor in vessels and transplant efficiency is still low in animal models, except in mice. Subcutaneous islet transplantation using a two-step approach has been proposed, in which a favorable cavity is first prepared using various materials, followed by islet transplantation into the preformed cavity. We previously reported the efficacy of pretreatment using gelatin hydrogel nonwoven fabric (GHNF), and the length of the pretreatment period influenced the results in a mouse model. We investigated whether the preimplantation of GHNF could improve the subcutaneous islet transplantation outcomes in a rat model. GHNF sheets sandwiching a silicone spacer (GHNF group) and silicone spacers without GHNF sheets (control group) were implanted into the subcutaneous space of recipients three weeks before islet transplantation, and diabetes was induced seven days before islet transplantation. Syngeneic islets were transplanted into the space where the silicone spacer was removed. Blood glucose levels, glucose tolerance, immunohistochemistry, and neovascularization were evaluated. The GHNF group showed significantly better blood glucose changes than the control group (p < 0.01). The cure rate was significantly higher in the GHNF group (p < 0.05). The number of vWF-positive vessels was significantly higher in the GHNF group (p < 0.01), and lectin angiography showed the same tendency (p < 0.05). The expression of laminin and collagen III around the transplanted islets was also higher in the GHNF group (p < 0.01). GHNF pretreatment was effective in a rat model, and the main mechanisms might be neovascularization and compensation of the extracellular matrices.

Regenerative potential of basic fibroblast growth factor contained in biodegradable gelatin hydrogel microspheres applied following vocal fold injury: Early effect on tissue repair in a rabbit model / Potencial regenerativo do fator básico de crescimento de fibroblastos contido em microesferas biodegradáveis de hidrogel de gelatina aplicadas após lesão de prega vocal: efeito inicial no reparo tecidual em modelo de coelho

Abstract Introduction Postoperative dysphonia is mostly caused by vocal fold scarring, and careful management of vocal fold surgery has been reported to reduce the risk of scar formation. However, depending on the vocal fold injury, treatment of postoperative dysphonia can be challenging. Objective The goal of the current study was to develop a novel prophylactic regenerative approach for the treatment of injured vocal folds after surgery, using biodegradable gelatin hydrogel microspheres as a drug delivery system for basic fibroblast growth factor. Methods Videoendoscopic laryngeal surgery was performed to create vocal fold injury in 14 rabbits. Immediately following this procedure, biodegradable gelatin hydrogel microspheres with basic fibroblast growth factor were injected in the vocal fold. Two weeks after injection, larynges were excised for evaluation of vocal fold histology and mucosal movement. Results The presence of poor vibratory function was confirmed in the injured vocal folds. Histology and digital image analysis demonstrated that the injured vocal folds injected with gelatin hydrogel microspheres with basic fibroblast growth factor showed less scar formation, compared to the injured vocal folds injected with gelatin hydrogel microspheres only, or those without any injection. Conclusion A prophylactic injection of basic fibroblast growth factor -containing biodegradable gelatin hydrogel microspheres demonstrates a regenerative potential for injured vocal folds in a rabbit model.

Resumo Introdução A disfonia pós-operatória é causada principalmente por cicatrizes nas pregas vocais. Tem sido relatado que o manejo cuidadoso da cirurgia das pregas vocais reduz o risco de formação de cicatriz. No entanto, a depender da lesão da prega vocal, o tratamento da disfonia pós-operatória pode ser desafiador. Objetivo Desenvolver uma nova abordagem regenerativa profilática para o tratamento de pregas vocais lesionadas após a cirurgia, com microesferas biodegradáveis de hidrogel de gelatina como sistema de administração de medicamentos para o Fator Básico de Crescimento de Fibroblastos (bFGF). Método A cirurgia laríngea videoendoscópica foi feita para criar lesão nas pregas vocais em 14 coelhos. Imediatamente após esse procedimento, microesferas biodegradáveis de hidrogel de gelatina com bFGF foram injetadas na prega vocal. Duas semanas após a injeção, as laringes foram excisadas para avaliação da histologia das pregas vocais e do movimento da mucosa. Resultados A presença de função vibratória deficiente foi confirmada nas pregas vocais lesionadas. A histologia e a análise de imagem digital demonstraram que as pregas vocais lesionadas injetadas com microesferas de hidrogel de gelatina com bFGF apresentaram menor formação de cicatriz, em comparação com as pregas vocais lesionadas injetadas apenas com microesferas de hidrogel de gelatina ou aquelas sem injeção. Conclusão Uma injeção profilática de microesferas biodegradáveis de hidrogel de gelatina com bFGF demonstra um potencial regenerativo para pregas vocais lesionadas em um modelo de coelho.