Release Of Fibroblast Growth Factor Research Articles

Abstract PO3-24-11: Impact of Circulating Extracellular Vesicles derived from Obese Women on Pro-Tumor Functions of Stromal Fibroblasts in Breast Cancer

Abstract The incidence of obesity has risen sharply worldwide, and growing evidence shows its impact on several malignancies, including breast cancer (BC). Excessive adiposity and high body mass index (BMI) significantly affect BC incidence, prognosis, and therapeutic response of patients. Indeed, obese women exhibit larger tumor size, limph node involvement, metastatic spread, and poorer survival outcomes. Preclinical and clinical studies indicated that the obese setting provides local and systemic modifications that may stimulate BC progression and influence tumor microenvironment, particularly composed of stromal fibroblasts (SF). The mechanisms behind this interplay are likely to be multifactorial and may involve important adipocyte-derived mediators, such as adipokines and growth factors. Aside from these soluble factors, extracellular vesicles (EVs), nanoscale lipid-bilayer enclosed vesicles released by a variety of cells, are emerging as powerful regulators of cell-to-cell communication able to promote BC initiation, growth, metastatic dissemination and drug resistance. However, the potential impact of obesity-derived EVs in affecting tumor-stimulatory features of SF has not been yet investigated. To this aim, circulating EVs were isolated from the serum of women categorized as normal weight (NW; 18 > BMI < 24.9 Kg/m2) and overweight/obese (OW/Ob; BMI > 25 Kg/m2). Immortalised human mammary control fibroblasts (CF), their cancer-associated counterparts (exp-CAFs), and human CAFs, isolated from biopsies of primary BC, were used as experimental models for stromal fibroblasts. Human MCF-7 and T47D BC cells were employed as experimental cell models for mammary carcinoma in co-culture experiments. Circulating EVs were successfully extracted from the serum of NW and OW/Ob women, and characterized by their shapes, size and protein markers. Transmission Electron Microscopy (TEM), and Nanoparticle Tracking Analysis (NTA) showed that EVs in the isolated fractions were oval or bowl-shaped with a size range between 50-200 nm. In accordance with the Minimal Information for Studies of Extracellular Vesicles (MISEV) 2018, enrichment of the EV markers TSG101, CD81, and CD63 were all detected in the EV isolated fractions. Interestingly, elevated levels of circulating EVs were detected in OW/Ob women compared to NW subjects. Treatment of CF with OW/Ob-EVs resulted in an increased cell motility, invasiveness, contractility along with an up-regulation of CF markers. BC cells cocultured with conditioned medium (CM) derived from OW/Ob-EV-treated CF exhibited higher anchorage-independent growth and migratory capacity than BC cells cocultured with CM derived from NW-EV-treated CF. Moreover, OW/Ob-EVs enhanced tumor-stimulatory activities of exp-CAFs and CAFs, further highlighting how obese-related EVs may have the potential to modulate fibroblast phenotype in BC. Finally, cytokine arrays revealed that treatment of CF with OW/Ob EVs was associated with an enhanced release of Fibroblast Growth Factor 19 and Cystatin C, factors that are closely related to BC growth and development. In conclusion, our data provide first evidence for the functional importance of EVs isolated from obese women in impacting tumor-stroma cross-talk and drive BC progression. Since obesity and its pathophysiological sequelae are on the rise, this new knowledge may help to identify specific biomarkers and innovative targets (i.e. FGF-19, and Cystatin C) that may allow a personalized management of patients affected by BC and obesity. Citation Format: Ines Barone, Piercarlo Del Console, Felice Maria Accattatis, Luca Gelsomino, Giuseppina Augimeri, Ennio Avolio, Sebastiano Andò, Daniela Bonofiglio, Cinzia Giordano, Stefania Catalano. Impact of Circulating Extracellular Vesicles derived from Obese Women on Pro-Tumor Functions of Stromal Fibroblasts in Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-24-11.

Facile and rapid fabrication of a novel 3D-printable, visible light-crosslinkable and bioactive polythiourethane for large-to-massive rotator cuff tendon repair

Facile and rapid 3D fabrication of strong, bioactive materials can address challenges that impede repair of large-to-massive rotator cuff tears including personalized grafts, limited mechanical support, and inadequate tissue regeneration. Herein, we developed a facile and rapid methodology that generates visible light-crosslinkable polythiourethane (PHT) pre-polymer resin (∼30 min at room temperature), yielding 3D-printable scaffolds with tendon-like mechanical attributes capable of delivering tenogenic bioactive factors. Ex vivo characterization confirmed successful fabrication, robust human supraspinatus tendon (SST)-like tensile properties (strength: 23 MPa, modulus: 459 MPa, at least 10,000 physiological loading cycles without failure), excellent suture retention (8.62-fold lower than acellular dermal matrix (ADM)-based clinical graft), slow degradation, and controlled release of fibroblast growth factor-2 (FGF-2) and transforming growth factor-β3 (TGF-β3). In vitro studies showed cytocompatibility and growth factor-mediated tenogenic-like differentiation of mesenchymal stem cells. In vivo studies demonstrated biocompatibility (3-week mouse subcutaneous implantation) and ability of growth factor-containing scaffolds to notably regenerate at least 1-cm of tendon with native-like biomechanical attributes as uninjured shoulder (8-week, large-to-massive 1-cm gap rabbit rotator cuff injury). This study demonstrates use of a 3D-printable, strong, and bioactive material to provide mechanical support and pro-regenerative cues for challenging injuries such as large-to-massive rotator cuff tears.

A biomimetic approach to modulating the sustained release of fibroblast growth factor 2 from fibrin microthread scaffolds

Aim: The pleiotropic effect of fibroblast growth factor 2 (FGF2) on promoting myogenesis, angiogenesis, and innervation makes it an ideal growth factor for treating volumetric muscle loss (VML) injuries. While an initial delivery of FGF2 has demonstrated enhanced regenerative potential, the sustained delivery of FGF2 from scaffolds with robust structural properties as well as biophysical and biochemical signaling cues has yet to be explored for treating VML. The goal of this study is to develop an instructive fibrin microthread scaffold with intrinsic topographic alignment cues as well as regenerative signaling cues and a physiologically relevant, sustained release of FGF2 to direct myogenesis and ultimately enhance functional muscle regeneration. Methods: Heparin was passively adsorbed or carbodiimide-conjugated to microthreads, creating a biomimetic binding strategy, mimicking FGF2 sequestration in the extracellular matrix (ECM). It was also evaluated whether FGF2 incorporated into fibrin microthreads would yield sustained release. It was hypothesized that heparin-conjugated and co-incorporated (co-inc) fibrin microthreads would facilitate sustained release of FGF2 from the scaffold and enhance in vitro myoblast proliferation and outgrowth. Results: Toluidine blue staining and Fourier transform infrared spectroscopy confirmed that carbodiimide-conjugated heparin bound to fibrin microthreads in a dose-dependent manner. Release kinetics revealed that heparin-conjugated fibrin microthreads exhibited sustained release of FGF2 over a period of one week. An in vitro assay demonstrated that FGF2 released from microthreads remained bioactive, stimulating myoblast proliferation over four days. Finally, a cellular outgrowth assay suggests that FGF2 promotes increased outgrowth onto microthreads. Conclusions: It was anticipated that the combined effects of fibrin microthread structural properties, topographic alignment cues, and FGF2 release profiles will facilitate the fabrication of a biomimetic scaffold that enhances the regeneration of functional muscle tissue for the treatment of VML injuries.

Ag nanocomposite hydrogels with immune and regenerative microenvironment regulation promote scarless healing of infected wounds

BackgroundBacterial infection, complex wound microenvironment and persistent inflammation cause delayed wound healing and scar formation, thereby disrupting the normal function and appearance of skin tissue, which is one of the most problematic clinical issues. Although Ag NPs have a strong antibacterial effect, they tend to oxidize and form aggregates in aqueous solution, which reduces their antibacterial efficacy and increases their toxicity to tissues and organs. Current research on scar treatment is limited and mainly relies on growth factors and drugs to reduce inflammation and scar tissue formation. Therefore, there is a need to develop methods that effectively combine drug delivery, antimicrobial and anti-inflammatory agents to modulate the wound microenvironment, promote wound healing, and prevent skin scarring.ResultsHerein, we developed an innovative Ag nanocomposite hydrogel (Ag NCH) by incorporating Ag nanoparticles (Ag NPs) into a matrix formed by linking catechol-modified hyaluronic acid (HA-CA) with 4-arm PEG-SH. The Ag NPs serve dual functions: they act as reservoirs for releasing Ag/Ag+ at the wound site to combat bacterial infections, and they also function as cross-linkers to ensure the sustained release of basic fibroblast growth factor (bFGF). The potent antibacterial effect of the Ag NPs embedded in the hydrogel against S.aureus was validated through comprehensive in vitro and in vivo analyses. The microstructural analysis of the hydrogels and the in vitro release studies confirmed that the Ag NCH possesses smaller pore sizes and facilitates a slower, more sustained release of bFGF. When applied to acute and infected wound sites, the Ag NCH demonstrated remarkable capabilities in reshaping the immune and regenerative microenvironment. It induced a shift from M1 to M2 macrophage polarization, down-regulated the expression of pro-inflammatory factors such as IL-6 and TNF-α, and up-regulated the expression of anti-inflammatory IL-10. Furthermore, the Ag NCH played a crucial role in regulating collagen deposition and alignment, promoting the formation of mature blood vessels, and significantly enhancing tissue reconstruction and scarless wound healing processes.ConclusionsWe think the designed Ag NCH can provide a promising therapeutic strategy for clinical applications in scarless wound healing and antibacterial therapy.Graphical

Adhesivity-tuned bioactive gelatin/gellan hybrid gels drive efficient wound healing

Gelatin-based hydrogels have been widely used for wound healing applications. However, increase in ligand density and reduction in pore size with increasing gelatin concentration may delay wound healing by limiting cell infiltration. In this study, we address this shortcoming by combining gelatin with gellan—which is super hydrophilic and non-adhesive to cells. We show that UV crosslinked hybrid gels composed of methacrylated gelatin (GelMA) and methacrylated gellan gum (mGG), possess considerably larger pores and improved mechanical properties compared to GelMA gels. Reduced spreading and reduced formation of focal adhesions on hybrid gels combined with lower contractility and faster detachment upon trypsin-induced de-adhesion suggests that hybrid gels are less adhesive than GelMA gels. Gradual release of fibroblast growth factor (FGF) and silver nanoparticles (AgNPs) incorporated in hybrid gels not only boosts cell migration, but also confers anti-bacterial activity against gram-positive and gram-negative bacteria at concentrations nontoxic to cells. Full thickness wound healing in Wistar rats revealed increased granulation tissue formation in hybrid gels, fastest epithelialization and highest collagen deposition in rats treated with FGF entrapped hybrid gels. Together, our results demonstrate how adhesive tuning and incorporation of bioactive factors can be synergistically combined for achieving complete wound healing.

Sustained release of basic fibroblast growth factor in micro/nanofibrous scaffolds promotes annulus fibrosus regeneration.

Tissue engineering has promising applications in the treatment of intervertebral disc degeneration (IDD). The annulus fibrosus (AF) is critical for maintaining the physiological function of the intervertebral disc (IVD), but the lack of vessels and nutrition in AF makes it difficult to repair. In this study, we used hyaluronan (HA) micro-sol electrospinning and collagen type I (Col-I) self-assembly techniques to fabricate layered biomimetic micro/nanofibrous scaffolds, which released basic fibroblast growth factor (bFGF) to promote AF repair and regeneration after discectomy and endoscopic transforaminal discectomy. The bFGF enveloped in the core of the poly-L-lactic-acid (PLLA) core-shell structure was released in a sustained manner and promoted the adhesion and proliferation of AF cells (AFCs). Col-I could self-assemble on the shell of the PLLA core-shell scaffold to mimic the extracellular matrix (ECM) microenvironment, providing structural and biochemical cues for the regeneration of AF tissue. The in vivo studies showed that the micro/nanofibrous scaffolds promoted the repair of AF defects by simulating the microstructure of native AF tissue and inducing endogenous regeneration mechanism. Taken together, the biomimetic micro/nanofibrous scaffolds have clinical potential for the treatment of AF defects caused by IDD. STATEMENT OF SIGNIFICANCE: The annulus fibrosus (AF) is essential for the intervertebral disc(IVD) physiological function, yet it lacks vascularity and nutrition, making repair difficult. Micro-sol electrospinning technology and collagen type I (Col-I) self-assemblytechniquewere combined in this study to create a layered biomimetic micro/nanofibrous scaffold that releases basic fibroblast growth factor (bFGF) to promote AF repair and regeneration. Col-I could mimic the extracellular matrix (ECM) microenvironment,in vivo, offering structural and biochemical cues for AF tissue regeneration. This research indicates that micro/nanofibrous scaffolds have clinical potential for treating AF deficits induced by IDD.

Fibroblasts are the most suitable cell source for regenerative medicine due to their high intracellular fibroblast growth factor 2 content

In our previous study, we found that dry-preserved multilayered fibroblast cell sheets promoted angiogenesis and wound healing in a mouse ulcer model by releasing high levels of intracellular fibroblast growth factor 2 (FGF2), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF), from dried cells. In the present study, to identify which cell types are suitable for human dry-preserved cell sheets (dry sheets), we compared the intracellular FGF2 levels in seven types of cells reported as cell sheets for clinical use or preclinical studies. FGF2 levels were high in mesenchymal cells, including human oral fibroblasts (HOFs) and human dermal fibroblasts (HDFs), human dental pulp stem cells (DPSCs), and human mesenchymal stem cells (MSCs); in contrast, FGF2 levels in human umbilical vascular endothelial cells (HUVECs), human skeletal muscle myoblasts (SkMMs), and human epidermal keratinocytes (HEKs) were remarkably low, approximately 25% those in fibroblasts. In addition, we prepared dry sheets from HOFs, DPSCs, and MSCs, and analyzed the growth factors released from each dry sheet upon rehydration. High levels of FGF2, HGF, and VEGF were detected in the eluate prepared by immersing each dry sheet. In particular, FGF2 and HGF were the most abundant in HOFs. An in vitro cell proliferation assay showed that these eluates significantly enhanced HUVEC proliferation compared to control cells. Furthermore, cells incubated with HOF eluate showed significantly higher cell proliferation than cells incubated with DPSC and MSC eluates. However, this proliferative response was significantly blocked by FGF2-neutralizing antibodies. These results demonstrate that growth factors released from human dry sheets have physiological activity and that this activity is mainly mediated by the effect of FGF2. Fibroblasts are ideal for the clinical application of dry-preserved cell sheets in humans owing to their high intracellular FGF2 content, fast cell proliferation, ease of handling, availability, and low culture costs, making them the most suitable cell source for regenerative medicine, with FGF2 release as the mechanism of action.

Melatonin increases collagen content accumulation and Fibroblast Growth Factor-2 secretion in cultured human cardiac fibroblasts

BackgroundThe extracellular matrix serves as a scaffold for cardiomyocytes, allowing them to work in accord. In rats, collagen metabolism within a myocardial infarction scar is regulated by melatonin. The present study determines whether melatonin influences matrix metabolism within human cardiac fibroblast cultures and examines the underlying mechanism.MethodsThe experiments were performed on cultures of cardiac fibroblasts. The Woessner method, 1,9-dimethylmethylene blue assay, enzyme-linked immunosorbent assay and quantitative PCR were used in the study.ResultsMelatonin treatment lowered the total cell count within the culture, elevated necrotic and apoptotic cell count as well as augmented cardiac fibroblast proliferation, and increased total, intracellular, and extracellular collagen within the fibroblast culture; it also elevated type III procollagen α1 chain expression, without increasing procollagen type I mRNA production. The pineal hormone did not influence matrix metalloproteinase-2 (MMP-2) release or glycosaminoglycan accumulation by cardiac fibroblasts. Melatonin increased the release of Fibroblast Growth Factor-2 (FGF-2) by human cardiac fibroblasts, but cardiotrophin release was not influenced.ConclusionWithin human cardiac fibroblast culture, collagen metabolism is regulated by melatonin. The profibrotic effect of melatonin depends on the elevation of procollagen type III gene expression, and this could be modified by FGF-2. Two parallel processes, viz., cell elimination and proliferation, induced by melatonin, lead to excessive replacement of cardiac fibroblasts.

Enzyme-responsive microneedle patch for bacterial infection and accelerated healing of diabetic wounds

Chronic diabetic wounds are caused by an array of pathologies. Pathogenic bacteria such as S. aureus can easily invade hosts with deficient immunity. In this study, we developed a multifunctional hyaluronic acid methacrylate (HAMA)/carboxymethyl chitosan (CMCS) core‐shell microneedle patch with sodium alginate as a moisture layer to maintain the moisture balance in the wound exudate. Microneedles are stably held on the wound by a chitosan adhesive layer. Sufficient strength supports microneedle to punch into the biofilm and induce dispersion. S. aureus secreted hyaluronidase to degrade the HAMA shell of the microneedle and promote the release of graphene oxide with ASyycF, triggering strong antibacterial activity by posttranscriptional regulation and physical cutting effects. The continual release of basic fibroblast growth factor from the CMCS core was able to accelerate angiogenesis, collagen synthesis and immunity modulation, working synergistically with biodegraded HAMA. The multifunctional microneedle patches thereby provide a potential approach by accelerating the healing of infected diabetic wounds.

Facilely preparing carboxymethyl chitosan/hydroxyethyl cellulose hydrogel films for protective and sustained release of fibroblast growth factor 2 to accelerate dermal tissue repair

Facilely preparing carboxymethyl chitosan/hydroxyethyl cellulose hydrogel films for protective and sustained release of fibroblast growth factor 2 to accelerate dermal tissue repair

Effects of hypoxia on bronchial and alveolar epithelial cells linked to pathogenesis in chronic lung disorders.

Introduction: Chronic lung disorders involve pathological alterations in the lung tissue with hypoxia as a consequence. Hypoxia may influence the release of inflammatory mediators and growth factors including vascular endothelial growth factor (VEGF) and prostaglandin (PG)E2. The aim of this work was to investigate how hypoxia affects human lung epithelial cells in combination with profibrotic stimuli and its correlation to pathogenesis. Methods: Human bronchial (BEAS-2B) and alveolar (hAELVi) epithelial cells were exposed to either hypoxia (1% O2) or normoxia (21% O2) during 24h, with or without transforming growth factor (TGF)-β1. mRNA expression of genes and proteins related to disease pathology were analysed with qPCR, ELISA or immunocytochemistry. Alterations in cell viability and metabolic activity were determined. Results: In BEAS-2B and hAELVi, hypoxia significantly dowregulated genes related to fibrosis, mitochondrial stress, oxidative stress, apoptosis and inflammation whereas VEGF receptor 2 increased. Hypoxia increased the expression of Tenascin-C, whereas both hypoxia and TGF-β1 stimuli increased the release of VEGF, IL-6, IL-8 and MCP-1 in BEAS-2B. In hAELVi, hypoxia reduced the release of fibroblast growth factor, epidermal growth factor, PGE2, IL-6 and IL-8, whereas TGF-β1 stimulus significantly increased the release of PGE2 and IL-6. TGF-β1 stimulated BEAS-2B cells showed a decreased release of VEGF-A and IL-8, while TGF-β1 stimulated hAELVi cells showed a decreased release of PGE2 and IL-8 during hypoxia compared to normoxia. Metabolic activity was significantly increased by hypoxia in both epithelial cell types. Discussion: In conclusion, our data indicate that bronchial and alveolar epithelial cells respond differently to hypoxia and profibrotic stimuli. The bronchial epithelium appears more responsive to changes in oxygen levels and remodelling processes compared to the alveoli, suggesting that hypoxia may be a driver of pathogenesis in chronic lung disorders.

Development of Growth Factor Releasing Hyaluronic Acid-Based Hydrogel for Pulp Regeneration: A Preliminary Study.

Growth factors play essential roles as signaling molecules in pulp regeneration. We investigated the effect of a hyaluronic acid (HA)-collagen hybrid hydrogel with controlled release of fibroblast growth factor (FGF)-2 and platelet-derived growth factor (PDGF)-BB on human pulp regeneration. The cell interaction and cytotoxicity of the HA-collagen hybrid hydrogel, the release kinetics of each growth factor, and the effects of the released growth factors on pulp cell proliferation were examined. The vitality of pulp cells was maintained. The amounts of FGF-2 and PDGF-BB released over 7 days were 68% and 50%, respectively. Groups with a different concentration of growth factor (FGF-2: 100, 200, 500, and 1000 ng/mL; PDGF-BB: 10, 50, 100, 200, and 500 ng/mL) were experimented on days 1, 3, 5, and 7. Considering FGF-2 concentration, significantly increased pulp cell proliferation was observed on days 1, 3, 5, and 7 in the 100 ng/mL group and on days 3, 5, and 7 in the 200 ng/mL group. In the case of PDGF-BB concentration, significantly increased pulp cell proliferation was observed at all four time points in the 100 ng/mL group and on days 3, 5, and 7 in the 50, 200, and 500 ng/mL groups. This indicates that the optimal concentration of FGF-2 and PDGF-BB for pulp cell proliferation was 100 ng/mL and that the HA-collagen hybrid hydrogel has potential as a controlled release delivery system for FGF-2 and PDGF-BB.

Surface biofunctional bFGF-loaded electrospun suture accelerates incisional wound healing

Surgical suture plays an important role in increasing wound repair. However, the healing efficacy of sutures currently is still not satisfactory due to their failure in regulating healing biology. Therefore, developing functional sutures are highly required. Herein, we fabricated a new degradable suture to control the release of basic fibroblast growth factor (bFGF) for incisional wound healing. The suture (bFGF-DA@PCL) was simply made by anchoring bFGF onto the surface of the electrospun polycaprolactone (PCL) suture through the assistance of dopamine with a bFGF loading efficiency around 80 %. The introduction of dopamine to the suture also increased the mechanical strength of suture from 17 kPa to 27 kPa. The in vitro data evidenced that the suture could effectively prolong bFGF release up to 10 days and enhance cell adhesion and proliferation. Further in vivo results demonstrated that the suture could increase wound healing and induce a complete wound closure within 13 days. Moreover, the suture was found to accelerate skin mechanical restoration with a recovery of maximum strength to 87.1 % of the healthy skin. The suture was also revealed to help the skin wound healing by promoting granulation tissue formation, collagen deposition, reepithelization, and basement membrane reconstruction.

Proteomics reveals the potential mechanism of Tanshinone IIA in promoting the ExVivo expansion of human bone marrow mesenchymal stem cells.

Bone marrow mesenchymal stem cells (BMSCs) are a promising cell type for tissue engineering, however, the application of BMSCs is largely hampered by the limited number harvested from bone marrow cells. The methods or strategies that focused on promoting the capacity of BMSCs expansion exvivo become more and more important. Tanshinone IIA (Tan IIA), the main active components of Danshen, has been found to promote BMSCs proliferation, but the underlying mechanism is still unclear. The aim of this study is to explore the effect and underlying mechanism of Tan IIA on the expansion capacity of hBMSCs exvivo. In this present study, the effect of Tan IIA on the expansion capacity of BMSCs from human was investigated, and quantitative proteome analysis was applied furtherly to identify the differentially expressed proteins (DEPs) and the molecular signaling pathways in Tan IIA-treated hBMSCs. Finally, molecular biology skills were employed to verify the proposed mechanism of Tan IIA in promoting hBMSCs expansion. The results showed that a total of 84 DEPs were identified, of which 51 proteins were upregulated and 33 proteins were downregulated. Besides, Tan IIA could promote hBMSCs proliferation by regulating the progression of S phase via increasing the release of fibroblast growth factor 2 (FGF2), FGF-mediated PI3K/AKT signaling pathways may play an important role in Tan IIA's effect on hBMSCs expansion. This study employed molecular biology skills combined with quantitative proteome analysis, to some extent, clarified the mechanism of Tan IIA's effect on promoting hBMSCs proliferation, and will give a hint that Tan IIA may have the potential to be used for BMSCs applications in cell therapies in the future.

Comparison of Wound Healing Effect of Skin Micrograft Impregnated into Two Kinds of Artificial Dermis in a Murine Wound Model.

Skin MG was prepared from the skin of C57BL/6JJcl mice using Rigeneracons and administered onto Pelnac Gplus and Integra sheets. The amount of MG suspension impregnated in Pelnac Gplus and Integra was evaluated. Pelnac Gplus and Integra sheets combined with MG were applied to murine defects, and wound area, neoepithelium length, granulation tissue formation, and newly formed capillaries were compared with the control groups on days 7 and 14. The weight percentage of the MG absorbed by Pelnac Gplus and Integra was 88.8% ± 3.5% and 28.2% ± 7.0%, respectively (P < 0.05). In the in vivo experiment, the area of newly formed granulation tissue and both the number and area of newly formed capillaries in the PelnacG + MG group were significantly larger than those in the control group at 14 days after implantation (P < 0.05). Skin MG was successfully impregnated into Pelnac Gplus by simple administration but not into Integra. Administration of skin MG into the Pelnac Gplus promoted granulation formation and angiogenesis. Pelnac Gplus was more suitable than Integra in the combination therapy.

Drug-preloadable methacrylated gelatin microspheres fabricated using an aqueous two-phase system

Gelatin microspheres (GMS) can retain biomolecules and be incorporated into artificial tissues and organs for tissue regeneration. However, the inactivation of biomolecules during the conventional fabrication process of GMS requires postloading of biomolecules to prefabricated GMS. Herein, a novel method for fabricating drug-preloaded GMS using a water-in-water (w/w) emulsification technique, is reported. A highly concentrated gelatin methacrylate (Gm) solution containing fibroblast growth factor 2 (FGF2), a model drug, was emulsified in a highly concentrated polyethylene glycol solution, and the mixture was irradiated with ultraviolet light. The obtained water-in-water gelatin methacrylate microspheres (w/w GmMS) were superior to conventional GMS in terms of stability, FGF2-loading efficiency, and sustained release of FGF2. The FGF2-loaded w/w GmMS efficiently activated the proliferation of adipose tissue-derived mesenchymal stem cells (ASCs). In addition, FGF2-loaded w/w GmMS incorporated into multicellular spheroids of ASCs increased the viability of ASCs in the spheroids. The therapeutic efficacy of ASC spheroids in a wound healing mouse model was significantly improved by the incorporation of FGF2-loaded w/w GmMS. These results indicate that drug-preloadable w/w GmMS can be widely applied in tissue engineering and regenerative medicine strategies.

Free-standing multilayer films as growth factor reservoirs for future wound dressing applications

Chronic skin wounds place a high burden on patients and health care systems. The use of angiogenic and mitogenic growth factors can facilitate the healing but growth factors are quickly inactivated by the wound environment if added exogenously. Here, free-standing multilayer films (FSF) are fabricated from chitosan and alginate as opposing polyelectrolytes in an alternating manner using layer-by-layer technique. One hundred bilayers form an about 450 μm thick, detachable free-standing film that is subsequently crosslinked by either ethyl (dimethylaminopropyl) carbodiimide combined with N-hydroxysuccinimide (E-FSF) or genipin (G-FSF). The characterization of swelling, oxygen permeability and crosslinking density shows reduced swelling and oxygen permeability for both crosslinked films compared to non-crosslinked films (N-FSF). Loading of fibroblast growth factor 2 (FGF2) into the films results in a sustained release from crosslinked FSF in comparison to non-crosslinked FSF. Biocompatibility studies in vitro with human dermal fibroblasts cultured underneath the films demonstrate increased cell growth and cell migration for all films with and without FGF2. Especially G-FSF loaded with FGF2 greatly increases cell proliferation and migration. In vivo biocompatibility studies by subcutaneous implantation in mice show that E-FSF causes an inflammatory tissue response that is absent in the case of G-FSF. N-FSF also represents a biocompatible film but shows early degradation. All FSF possess antibacterial properties against gram+ and gram- bacteria demonstrated by an agar diffusion disc assay. In summary, FSF made of alginate and chitosan crosslinked with genipin can act as a reservoir for the sustained release of FGF2, possessing high biocompatibility in vitro and in vivo. Moreover, G-FSF promotes growth and migration of human dermal fibroblasts and has antibacterial properties, which makes it an interesting candidate for bioactive wound.

Affibody-mediated controlled release of fibroblast growth factor 2

Protein therapeutics possess high target affinity and specificity, yet short residence times, which limit their broad utility. To overcome this challenge, we used affinity interactions to modulate protein release from a hydrogel delivery vehicle thereby prolonging therapeutic availability. Specifically, we designed an affibody-modified hyaluronan (HA)-based hydrogel as a delivery platform for fibroblast growth factor 2 (FGF2), a neuroprotective and neuroregenerative factor in the central nervous system (CNS). We identified a highly specific affibody binding partner with moderate affinity for FGF2 using yeast surface display and flow cytometry-based screening. Importantly, we demonstrated controlled release of bioactive FGF2 from the hydrogel by varying the ratio of affibody to protein and showed increased thermal stability of FGF2 in the presence of affibody. This versatile delivery platform will allow the distinct, simultaneous release of multiple proteins based on specific affinity interactions.

Chitosan nanoparticles encapsulated into PLA/gelatin fibers for bFGF delivery

Abstract Electrospinning is a trendy method because of the ease of use and the high surface-to-volume ratio. The mechanical and biological properties of polylactic acid (PLA) make it one of the most enticing polymers. Gelatin and PLA together are thought to enhance cellular behavior and hydrophilicity of scaffolds. Furthermore, chitosan nanoparticles (CNPs) can be incorporated into PLA fibers to achieve controlled growth factor release. This study utilized PLA–gelatin nanofibrous scaffolds in which CNPs were encapsulated within PLA fibers to achieve a controlled release of basic fibroblast growth factor (bFGF). To produce CNPs, a simple ionic gelation reaction was used. The optimal diameter of CNPs was determined by investigating chitosan to tricalciumphosphatesodium (TPP) ratio and TPP concentration. Using a spectrophotometer, we measured the release rate of bFGF from CNPS and scaffolds. Images from a scanning electron microscope (SEM) were used to assess the effect of various concentrations of PLA and gelatin on fiber diameter. The results showed that PLA–gelatin scaffolds could stimulate the release of growth factors and promote cell proliferation. Using a two-jet electrospinning device to produce PLA–gelatin fibers in combination with CNPs incorporated within PLA fibers to release the bFGF growth factor is the novelty of this study.

BFGF-incorporated composite biomaterial for bone regeneration

Injectable biomaterials obtain increasing attention for the repair of bone defect due to the advantage of defect margin adaptability and easy handling. Our previous studies found that RADA16 peptide hydrogel could significantly promote bone formation. In order to improve the mechanical force, RADA16 peptide hydrogel was used to fill the porous calciumsulfate/nano-hydroxyapatite(CaSO4/HA)cement biomaterial for the fabrication of RADA16/CaSO4/HA composite biomaterial. Especially, RADA16 peptide hydrogel had the ability to slowly release growth factors for bone regeneration. Here, RADA16/CaSO4/HA composite biomaterials afforded the controlled and sustainable release of basic fibroblast growth factor(bFGF) for more than 32 days. Compared to RADA16/CaSO4/HA biomaterial, RADA16 + bFGF/CaSO4/HA composite biomaterial could further improve in vitro osteogenic differentiation of MC3T3 cells as evidenced by the increased expression of osteogenic markers (i.e. runt-related transcription factor 2 [Runx2], osteocalcin [OCN] andalkaline phosphatase [ALP]) and in vivo bone formation of femoral condyle defects which were confirmed by histological staining and micro-CT analyses. These indicate that bFGF-incorporated RADA16/CaSO4/HA can further improve bone formation through the controlled release of bFGF, which provides a novel injectable biomaterial design to specifically release growth factors for bone defects.