Structural and biochemical investigation into stable FGF2 mutants with novel mutation sites and hydrophobic replacements for surface-exposed cysteines.

Fibroblast growth factor 2 (FGF2) is an attractive biomaterial for pharmaceuticals and functional cosmetics. To improve the thermo-stability of FGF2, we designed two mutants harboring four-point mutations: FGF2-M1 (D28E/C78L/C96I/S137P) and FGF2-M2 (D28E/C78I/C96I/S137P) through bioinformatics, molecular thermodynamics, and molecular modeling. The D28E mutation reduced fragmentation of the FGF2 wild type during preparation, and the substitution of a whale-specific amino acid, S137P, enhanced the thermal stability of FGF2. Surface-exposed cysteines that participate in oligomerization through intermolecular disulfide bond formation were substituted with hydrophobic residues (C78L/C78I and C96I) using the in silico method. High-resolution crystal structures revealed at the atomic level that the introduction of mutations stabilizes each local region by forming more favorable interactions with neighboring residues. In particular, P137 forms CH-π interactions with the side chain indole ring of W123, which seems to stabilize a ß-hairpin structure, containing a heparin-binding site of FGF2. Compared to the wild type, both FGF2-M1 and FGF2-M2 maintained greater solubility after a week at 45 °C, with their Tm values rising by ~ 5 °C. Furthermore, the duration for FGF2-M1 and FGF2-M2 to reach 50% residual activity at 45 °C extended to 8.8- and 8.2-fold longer, respectively, than that of the wild type. Interestingly, the hydrophobic substitution of surface-exposed cysteine in both FGF2 mutants makes them more resistant to proteolytic cleavage by trypsin, subtilisin, proteinase K, and actinase than the wild type and the Cys → Ser substitution. The hydrophobic replacements can influence protease resistance as well as oligomerization and thermal stability. It is notable that hydrophobic substitutions of surface-exposed cysteines, as well as D28E and S137P of the FGF2 mutants, were designed through various approaches with structural implications. Therefore, the engineering strategies and structural insights adopted in this study could be applied to improve the stability of other proteins.

Biofunctionalization of Cellulose Microcarriers Using a Carbohydrate Binding Module Linked with Fibroblast Growth Factor for the Expansion of Human Umbilical Mesenchymal Stromal Cells in Stirred Suspension Bioreactors.

Mesenchymal stromal cells (MSCs) have the potential to be used as autologous or allogenic cell therapy in several diseases due to their beneficial secretome and capacity for immunomodulation and differentiation. However, clinical trials using MSCs require a large number of cells. As an alternative to traditional culture flasks, suspension bioreactors provide a scalable platform to produce clinically relevant quantities of cells. When cultured in bioreactors, anchorage-dependent cells like MSCs require the addition of microcarriers, which provide a surface for cell attachment while in suspension. The best performing microcarriers are typically coated in animal derived proteins, which increases cellular attachment and proliferation but present issues from a regulatory perspective. To overcome this issue, a recombinant fusion protein was generated linking basic fibroblast growth factor (bFGF) to a cellulose-specific carbohydrate binding module (CBM) and used to functionalize the surface of cellulose microcarriers for the expansion of human umbilical MSCs in suspension bioreactors. The fusion protein was shown to support the growth of MSCs when used as a soluble growth factor in the absence of cellulose, readily bound to cellulose microcarriers in a dose-dependent manner, and ultimately improved the expansion of MSCs when grown in bioreactors using cellulose microcarriers. The use of CBM fusion proteins offers a simple method for the surface immobilization of growth factors to animal component-free substrates such as cellulose, which can be used alongside bioreactors to increase growth factor lifespan, decrease culture medium cost, and increase cell production in the manufacturing of therapeutic cells.

Bioinspired Collagen Scaffold Loaded with bFGF-Overexpressing Human Mesenchymal Stromal Cells Accelerating Diabetic Skin Wound Healing via HIF-1 Signal Pathway Regulated Neovascularization.

The healing of severe chronic skin wounds in chronic diabetic patients is still a huge clinical challenge due to complex regeneration processes and control signals. Therefore, a single approach is difficult in obtaining satisfactory therapeutic efficacy for severe diabetic skin wounds. In this study, we adopted a composite strategy for diabetic skin wound healing. First, we fabricated a collagen-based biomimetic skin scaffold. The human basic fibroblast growth factor (bFGF) gene was electrically transduced into human umbilical cord mesenchymal stromal cells (UC-MSCs), and the stable bFGF-overexpressing UC-MSCs (bFGF-MSCs) clones were screened out. Then, an inspired collagen scaffold loaded with bFGF-MSCs was applied to treat full-thickness skin incision wounds in a streptozotocin-induced diabetic rat model. The mechanism of skin damage repair in diabetes mellitus was investigated using RNA-Seq and Western blot assays. The bioinspired collagen scaffold demonstrated good biocompatibility for skin-regeneration-associated cells such as human fibroblast (HFs) and endothelial cells (ECs). The bioinspired collagen scaffold loaded with bFGF-MSCs accelerated the diabetic full-thickness incision wound healing including cell proliferation enhancement, collagen deposition, and re-epithelialization, compared with other treatments. We also showed that the inspired skin scaffold could enhance the in vitro tube formation of ECs and the early angiogenesis process of the wound tissue in vivo. Further findings revealed enhanced angiogenic potential in ECs stimulated by bFGF-MSCs, evidenced by increased AKT phosphorylation and elevated HIF-1α and HIF-1ß levels, indicating the activation of HIF-1 pathways in diabetic wound healing. Based on the superior biocompatibility and bioactivity, the novel bioinspired skin healing materials composed of the collagen scaffold and bFGF-MSCs will be promising for healing diabetic skin wounds and even other refractory tissue regenerations. The bioinspired collagen scaffold loaded with bFGF-MSCs could accelerate diabetic wound healing via neovascularization by activating HIF-1 pathways.

Extracellular matrix hydrogels with fibroblast growth factor 2 containing exosomes for reconstructing skin microstructures.

Decellularized extracellular matrix hydrogel (ECM hydrogel), a natural material derived from normal tissue with unique biocompatibility properties, is widely used for tissue repair. However, there are still problems such as poor biological activity and insufficient antimicrobial property. To overcome these drawbacks, fibroblast growth factor 2 (FGF 2) containing exosome (exoFGF 2) was prepared to increase the biological activity. Furthermore, the antimicrobial capacity of ECM hydrogel was optimised by using copper ions as a ligand-bonded cross-linking agent. The decellularized extracellular matrix hydrogel, intricately cross-linked with copper ions through ligand bonds and loaded with FGF 2 containing exosome (exoFGF 2@ECM/Cu2+ hydrogel), has demonstrated exceptional biocompatibility and antimicrobial properties. In vitro, exoFGF 2@ECM/Cu2+ hydrogel effectively promoted cell proliferation, migration, antioxidant and inhibited bacterial growth. In vivo, the wound area of rat treated with exoFGF 2@ECM/Cu2+ hydrogels were significantly smaller than that of other groups at Day 5 (45.24% ± 3.15%), Day 10 (92.20% ± 2.31%) and Day 15 (95.22% ± 1.28%). Histological examination showed that exoFGF 2@ECM/Cu2+ hydrogels promoted angiogenesis and collagen deposition. Overall, this hydrogel has the potential to inhibit bacterial growth and effectively promote wound healing in a variety of clinical applications.

Design and Discovery of New Collagen V-Derived FGF2-Blocking Natural Peptides Inhibiting Lung Squamous Cell Carcinoma In Vitro and In Vivo.

Aberrant FGF2/FGFR signaling is implicated in lung squamous cell carcinoma (LSCC), posing treatment challenges due to the lack of targeted therapeutic options. Designing drugs that block FGF2 signaling presents a promising strategy different from traditional kinase inhibitors. We previously reported a ColVα1-derived fragment, HEPV (127AA), that inhibits FGF2-induced angiogenesis. However, its large size may limit therapeutic application. This study combines rational peptide design, molecular dynamics simulations, knowledge-based prediction, and GUV and FRET assays to identify smaller peptides with FGF2-blocking properties. We synthesized two novel peptides, HBS-P1 (45AA) and HBS-P2 (66AA), that retained the heparin-binding site. Both peptides demonstrated anti-LSCC and antiangiogenesis properties in cell viability and microvessel network induction assays. In two LSCC subcutaneous models, HBS-P1, with its affinity for FGF2 and enhanced penetration ability, demonstrated substantial therapeutic potential without apparent toxicities. Our study provides the first evidence supporting the development of collagen V-derived natural peptides as FGF2-blocking agents for LSCC treatment.

Customized Vascular Repair Microenvironment: Poly(lactic acid)-Gelatin Nanofibrous Scaffold Decorated with bFGF and Ag@Fe3O4 Core-Shell Nanowires.

Vascular defects caused by trauma or vascular diseases can significantly impact normal blood circulation, resulting in serious health complications. Vascular grafts have evolved as a popular approach for vascular reconstruction with promising outcomes. However, four of the greatest challenges for successful application of small-diameter vascular grafts are (1) postoperative anti-infection, (2) preventing thrombosis formation, (3) utilizing the inflammatory response to the graft to induce tissue regeneration and repair, and (4) noninvasive monitoring of the scaffold and integration. The present study demonstrated a basic fibroblast growth factor (bFGF) and oleic acid dispersed Ag@Fe3O4 core-shell nanowires (OA-Ag@Fe3O4 CSNWs) codecorated poly(lactic acid) (PLA)/gelatin (Gel) multifunctional electrospun vascular grafts (bAPG). The Ag@Fe3O4 CSNWs have sustained Ag+ release and exceptional photothermal capabilities to effectively suppress bacterial infections both in vitro and in vivo, noninvasive magnetic resonance imaging (MRI) modality to monitor the position of the graft, and antiplatelet adhesion properties to promise long-term patency. The gradually released bFGF from the bAPG scaffold promotes the M2 macrophage polarization and enhances the recruitment of macrophages, endothelial cells (ECs) and fibroblast cells. This significant regulation of diverse cell behavior has been proven to be beneficial to vascular repair and regeneration both in vitro and in vivo. Therefore, this study supplies a method to prepare multifunctional vascular-repair materials and is expected to represent a significant guidance and reference to the development of biomaterials for vascular tissue engineering.

Janus sponge/electrospun fibre composite combined with EGF/bFGF/CHX promotes reconstruction in oral tissue regeneration.

Guided bone regeneration (GBR) is currently the most widely used bone augmentation technique in oral clinics. However, infection and soft tissue management remain the greatest challenge. In this study, a Janus sponge/electrospun fibre membrane containing epidermal growth factor (EGF), basic fibroblast growth factor (bFGF) and chlorhexidine (CHX) were prepared to optimize its application as a barrier membrane for GBR. The loose sponge part was covalently bonded with the fiber part which has a dense structure. The composed scaffold exhibited superior biocompatibility and antibacterial activity verified by in vitro test. A rat model of unilateral skull bone injury was used to confirm the effectiveness on both hard and soft tissue regeneration. The chitosan sponge on the soft tissue side containing EGF, bFGF and CHX had a loose structure, promoting collagen and cell regeneration and exerting an antibacterial effect. Meanwhile, the dense PLGA/PCL layer on the hard tissue side prevented fibroblast entry into the bone defect, thereby facilitating bone regeneration. The Janus composite scaffold provides a promising strategy for oral tissue restoration.

Self-Assembled Fibroblast Growth Factor Nanoparticles as a Therapeutic for Oxidant-Induced Neuronal and Skin Cell Injury.

Traumatic brain injury (TBI) and spinal cord injury (SCI) are neurological conditions that result from immediate mechanical injury, as well as delayed injury caused by local inflammation. Furthermore, TBI and SCI often lead to secondary complications, including pressure wounds of the skin, which can heal slowly and are prone to infection. Pressure wounds are localized areas of damaged tissue caused by prolonged pressure on the skin due to immobility and loss of neurological sensation. With the aim to ameliorate these symptoms, we investigated whether fibroblast growth factors 2 (FGF-2) could contribute to recovery. FGF-2 plays a significant role in both neurogenesis and skin wound healing. We developed a recombinant fusion protein containing FGF-2 linked to elastin-like polypeptides (FGF-ELP) that spontaneously self-assembles into nanoparticles at around 33 °C. The nanoparticle's size was ranging between 220 and 250 nm in diameter at 2 µM. We tested this construct for its ability to address neuronal and skin cell injuries. Hydrogen peroxide was used to induce oxidant-mediated injury on cultured neuronal cells to mimic the impact of reactive oxidants released during the inflammatory response in vivo. We found that FGF-ELP nanoparticles protected against hydrogen peroxide-mediated injury and promoted neurite outgrowth. In the skin cell models, cells were depleted from serum to mimic the reduced levels of nutrients and growth factors in chronic skin wounds. FGF-ELP increased the proliferation and migration of human keratinocytes, fibroblasts, and endothelial cells. FGF-ELP is, therefore, a potentially useful agent to provide both neuroprotection and promotion of cellular processes involved in skin wound healing.

Silk fibroin biohydrogel composites for loading and ordered release of multiple active ingredients with enhanced bioactivity.

Bioactive hydrogels are currently receiving significant attention. In this study, silk fibroin tyramine-modified gelatin hydrogels (SF-TG) with varying degrees of tyramine root substitution were explored. The physicochemical property and biocompatibility of low degree of substitution tyramine-modified gelatin hydrogel (SF-LTG) and high degree of substitution tyramine-modified gelatin hydrogel (SF-HTG) were compared. The results showed that SF-LTG possessed better mechanical property and higher biocompatibility. Thus, SF-LTG was selected as a bioactive matrix and loaded with basic fibroblast growth factor (bFGF); subsequently, curcumin-coupled chitosan rods (CCCRs-EGF) enriched with epidermal growth factor (EGF) were added to obtain SF-LTG-bFGF@CCCRs-EGF hydrogels. The results showed that SF-LTG-bFGF@CCCRs-EGF retained the basic structural and mechanical properties of the SF-LTG matrix gel material and underwent multiple loading and orderly release with different activities while displaying antioxidant, anti-inflammatory, antimicrobial, and pro-cellular proliferation activities and orderly regulation of activity during wound healing. Therefore, the SF-LTG-bFGF@CCCRs-EGF hydrogel is of great value in healing complex wounds.

Modeling interactions between Heparan sulfate and proteins based on the Heparan sulfate microarray analysis.

Heparan sulfate (HS), a sulfated polysaccharide abundant in the extracellular matrix, plays pivotal roles in various physiological and pathological processes by interacting with proteins. Investigating the binding selectivity of HS oligosaccharides to target proteins is essential, but the exhaustive inclusion of all possible oligosaccharides in microarray experiments is impractical. To address this challenge, we present a hybrid pipeline that integrates microarray and in silico techniques to design oligosaccharides with desired protein affinity. Using fibroblast growth factor 2 (FGF2) as a model protein, we assembled an in-house dataset of HS oligosaccharides on microarrays and developed two structural representations: a standard representation with all atoms explicit and a simplified representation with disaccharide units as "quasi-atoms." Predictive Quantitative Structure-Activity Relationship (QSAR) models for FGF2 affinity were developed using the Random Forest (RF) algorithm. The resulting models, considering the applicability domain, demonstrated high predictivity, with a correct classification rate of 0.81-0.80 and improved positive predictive values (PPV) up to 0.95. Virtual screening of 40 new oligosaccharides using the simplified model identified 15 computational hits, 11 of which were experimentally validated for high FGF2 affinity. This hybrid approach marks a significant step toward the targeted design of oligosaccharides with desired protein interactions, providing a foundation for broader applications in glycobiology.

A Biocompatible Nanofibers Modified by Plasma for Osteoblast Growth Differentiation.

This work employs nitrogen plasma immersion ion implantation (PIII) to modify electrospinning polylactic acid membranes and immobilizes basic fibroblast growth factors (bFGF) by forming crosslinking bonds. The study investigates the modified membranes' surface characteristics and the stimulatory effects of crosslinked bFGF polylactic acid membranes on osteoblast and fibroblast proliferation. The PIII process occurs under low vacuum conditions and is controlled by processing time and power pulse width. The experimental results indicate that, within a 400-second N2-PIII treatment, the spun fibers remain undamaged, demonstrating an increase in hydrophilicity (from 117° to 38°/36°) and nitrogen content (from 0% to 7.54%/8.05%). X-ray photoelectron spectroscopy analysis suggests the formation of a C-N-C=O crosslinked bond. Cell culture and activity assessments indicate that the PIII-treated and crosslinked bFGF film exhibits significantly higher cell growth activity (p < 0.05) than the untreated group. These intergroup differences are attributed to the surface crosslinking bond content. In osteogenic induction, the results for each day show that the treated group performs better. However, the intergroup disparities within the crosslinked bFGF group disappear with prolonged culture time due to the rapid osteogenesis prompted by bFGF. The findings suggest that PIII treatment of electrospinning polylactic acid membranes holds promise in promoting osteogenesis in bone tissue scaffolds.

Hybrid Micro-/Nanoprotein Platform Provides Endocrine-like and Extracellular Matrix-like Cell Delivery of Growth Factors.

Protein materials are versatile tools in diverse biomedical fields. Among them, artificial secretory granules (SGs), mimicking those from the endocrine system, act as mechanically stable reservoirs for the sustained release of proteins as oligomeric functional nanoparticles. Only validated in oncology, the physicochemical properties of SGs, along with their combined drug-releasing and scaffolding abilities, make them suitable as smart topographies in regenerative medicine for the prolonged delivery of growth factors (GFs). Thus, considering the need for novel, safe, and cost-effective materials to present GFs, in this study, we aimed to biofabricate a protein platform combining both endocrine-like and extracellular matrix fibronectin-derived (ECM-FN) systems. This approach is based on the sustained delivery of a nanostructured histidine-tagged version of human fibroblast growth factor 2. The GF is presented onto polymeric surfaces, interacting with FN to spontaneously generate nanonetworks that absorb and present the GF in the solid state, to modulate mesenchymal stromal cell (MSC) behavior. The results show that SGs-based topographies trigger high rates of MSCs proliferation while preventing differentiation. While this could be useful in cell therapy manufacture demanding large numbers of unspecialized MSCs, it fully validates the hybrid platform as a convenient setup for the design of biologically active hybrid surfaces and in tissue engineering for the controlled manipulation of mammalian cell growth.

All-in-one hydrogel patches with sprayed bFGF-loaded GelMA microspheres for infected wound healing studies.

The current wound healing process faces numerous challenges such as bacterial infection, inflammation and oxidative stress. However, wound dressings used to promote wound healing, are not well suited to meet the clinical needs. Hyaluronic acid (HA) not only has excellent water absorption and good biocompatibility but facilitates cell function and tissue regeneration. Dopamine, on the other hand, increases the overall viscosity of the hydrogel and possesses antioxidant property. Furthermore, chitosan exhibits outstanding performance in antimicrobial, anti-inflammatory and antioxidant activities. Basic fibroblast growth factor (bFGF) is conducive to cell proliferation and migration, vascular regeneration and wound healing. Hence, we designed an all-in-one hydrogel patch containing dopamine and chitosan framed by hyaluronic acid (HDC) with sprayed gelatin methacryloyl (GelMA) microspheres loaded with bFGF (HDC-bFGF). The hydrogel patch exhibits excellent adhesive, anti-inflammatory, antioxidant and antibacterial properties. In vitro experiments, the HDC-bFGF hydrogel patch not only showed significant inhibitory effect on RAW cell inflammation and Staphylococcus aureus (S. aureus) growth but also effectively scavenged free radicals, in addition to promoting the migration of 3 T3 cells. In the mice acute infected wound model, the HDC-bFGF hydrogel patch adhered to the wound surface greatly accelerated the healing process via its anti-inflammatory and antioxidant activities, bacterial inhibition and pro-vascularization effects. Therefore, the multifunctional HDC-bFGF hydrogel patch holds great promise for clinical application.

Electrospray Nano-Micro Composite Sodium Alginate Microspheres with Shape-Adaptive, Antibacterial, and Angiogenic Abilities for Infected Wound Healing.

Nonhealing infectious wounds, characterized by bacterial colonization, wound microenvironment destruction, and shape complexity, present an intractable problem in clinical practice. Inspired by LEGOs, building-block toys that can be assembled into desired shapes, we proposed the use of electrospray nano-micro composite sodium alginate (SA) microspheres with antibacterial and angiogenic properties to fill irregularly shaped wounds instantly. Specifically, porous poly(lactic-co-glycolic acid) (PLGA) microspheres (MSs) encapsulating basic fibroblast growth factor (bFGF) were produced by a water-in-oil-in-water double-emulsion method. Then, bFGF@MSs were blended with the SA solution containing ZIF-8 nanoparticles. The resultant solution was electrosprayed to obtain nano-micro composite microspheres (bFGF@MS/ZIF-8@SAMSs). The composite MSs' size could be regulated by PLGA MS mass proportion and electrospray voltage. Moreover, bFGF, a potent angiogenic agent, and ZIF-8, bactericidal nanoparticles, were found to release from bFGF@MS/ZIF-8@SAMSs in a controlled and sustainable manner, which promoted cell proliferation, migration, and tube formation and killed bacteria. Through experimentation on rat models, bFGF@MS/ZIF-8@SAMSs were revealed to adapt to wound shapes and accelerate infected wound healing because of the synergistic effects of antibacterial and angiogenic abilities. In summation, this study developed a feasible approach to prepare bioactive nano-micro MSs as building blocks that can fill irregularly shaped infected wounds and improve healing.

Integration of Zn2+, ATP, and bFGF to Nanodressing with Core-Shell Structure Fabricated by Emulsion Electrospinning for Wound Healing.

Basic fibroblast growth factor (bFGF) plays an important role in active wound repair. However, the existing dosage forms in clinical applications are mainly sprays and freeze-dried powders, which are prone to inactivation and cannot achieve a controlled release. In this study, a bioactive wound dressing named bFGF-ATP-Zn/polycaprolactone (PCL) nanodressing with a "core-shell" structure was fabricated by emulsion electrospinning, enabling the sustained release of bFGF. Based on the coordination and electrostatic interactions among bFGF, ATP, and Zn2+, as well as their synergistic effect on promoting wound healing, a bFGF-ATP-Zn ternary combination system was prepared with higher cell proliferation activity and used as the water phase for emulsion electrospinning. The bFGF-ATP-Zn/PCL nanodressing demonstrated improved mechanical properties, sustained release of bFGF, cytocompatibility, and hemocompatibility. It increased the proliferation activity of human dermal fibroblasts (HDFs) and enhanced collagen secretion by 1.39 and 3.45 times, respectively, while reducing the hemolysis rate to 3.13%. The application of the bFGF-ATP-Zn/PCL nanodressing in mouse full-thickness skin defect repair showed its ability to accelerate wound healing and reduce wound scarring within 14 days. These results provide a research basis for the development and application of this bioactive wound dressing product.

Expression, characterization and antivascular activity of amino acid sequence repeating collagen hexadecapeptide.

Type V collagen is an essential component of the extracellular matrix (ECM), and its remodeling releases specific protein fragments that can specifically inhibit endothelial cell responses such as proliferation, migration, and invasion. In this study, we have successfully constructed two engineered strains of Pichia pastoris capable of producing recombinant collagen through a new genetic engineering approach. Through high-density fermentation, the expression of 1605 protein and 1610 protein could reach 2.72 g/L and 4.36 g/L. With the increase of repetition times, the yield also increased. Bioactivity analysis showed that recombinant collagen could block the angiogenic effect of FGF-2 on endothelial cells by eliminating FGF-2-induced endothelial cell migration and invasion. Collectively, the recombinant proteins we successfully expressed have a wide range of potential for inhibiting angiogenesis in the biomaterials and biomedical fields.

Poly (Betulinic Acid) Nanoparticles Loaded with bFGF Improve Functional Recovery After Spinal Cord Injury.

Oxidative stress (OS) is one of the crucial molecular events of secondary spinal cord injury (SCI). Basic fibroblast growth factor (bFGF) is a multipotent cell growth factor with an anti-oxidant effect. However, bFGF has a short half-life in vivo, which limits its therapeutic application. Biodegradable polymers with excellent biocompatibility have been recently applied in SCI. The negative aspect is that polymers cannot provide a significant therapeutic effect. Betulinic acid (BA), a natural anti-inflammatory compound, has been polymerized into poly (betulinic acid) (PBA) to serve as a drug carrier for bFGF. This study explores the therapeutic effects and underlying molecular mechanisms of PBA nanoparticles (NPs) loaded with bFGF (PBA-bFGF NPs) in SCI. Results show that PBA-bFGF NPs produce remarkable biocompatibility in vivo and in vitro. The results also demonstrate that local delivery of PBA-bFGF NPs enhances motor function recovery, inhibits OS, mitigates neuroinflammation, and alleviates neuronal apoptosis following SCI. Furthermore, the results indicate that local delivery of PBA-bFGF NPs activates the nuclear factor erythroid 2-related factor 2 (Nrf-2) signaling pathway following SCI. In summary, results suggest that local delivery of PBA-bFGF NPs delivers potential therapeutic advantages in the treatment and management of SCI.

Assessment of serum levels and placental bed tissue expression of IGF-1, bFGF, and PLGF in patients with placenta previa complicated with placenta accreta spectrum disorders.

OBJECTIVE: This study aims to detect the serum levels of IGF-1, bFGF, and PLGF and their expressions in placental bed tissues of patients with placenta previa complicated with PAS disorders. METHODS: This case and control study included 40 multiparous pregnant women with complete placenta previa between 34 weeks and 38 weeks of gestation and they were divided into two groups: 25 patients with PAS (case group) and 15 patients without PAS (control group). The venous blood samples were collected 2 h before the cesarean section, and the placental bed tissues were taken intraoperatively at the placental implantation site and then were histologically examined to evaluate the gravity of the myometrial invasion of the placenta. According to FIGO PAS increasing grading, the 25 patients were also divided into three groups: PAS grade I group, PAS grade II group, and PAS grade III group. The concentrations of IGF-1, bFGF, and PLGF in serum were measured using ELISA, and the mean ratio of the relative mRNA expression of each biomarker in placental bed tissues was calculated using qRT-PCR. The staining intensity and the positive cells were quantitatively measured and expressed as means by using Image J software for IHC analysis. RESULTS: IGF-1 had low serum levels and high placental bed expression in placenta previa patients with PAS disorders compared to those without PAS (all p < 0.0001). PLGF had high serum levels (p = 0.0200) and high placental bed expression (p < 0.0001) in placenta previa patients with PAS disorders compared to those without PAS. IGF-1 serum levels decreased up to PAS grade II (means were 24.3 ± 4.03, 21.98 ± 3.29, and 22.03 ± 7.31, respectively for PAS grade I, PAS grade II, PAS grade III groups, p = 0.0006). PLGF serum levels increased up to PAS grade II (means were 12.96 ± 2.74, 14.97 ± 2.56, and 14.89 ± 2.14, respectively for the three groups, p = 0.0392). However, IGF-1 and PLGF mRNA placental bed expression increased up to PAS grade III. The relative expression of mRNA means for the three groups was 3.194 ± 1.40, 3.509 ± 0.63, and 3.872 ± 0.70, respectively for IGF-1; and 2.784 ± 1.14, 2.810 ± 0.71, and 2.869 ± 0.48, respectively for PLGF (all p < 0.0001). Their IHC (immunohistochemical) staining also had increasing trends, but p > 0.05. bFGF was not significantly expressed in placenta previa with PAS disorders in most of the analysis sections (p > 0.05). CONCLUSIONS: Low serum levels and high expression in placental bed tissues of IGF-1, or high serum levels and high expression in placental bed tissues of PLGF, may differentiate placenta previa patients with FIGO PAS grade I and PAS grade II from those without PAS disorders. However, they could not significantly predict the degree of placental invasiveness in FIGO PAS grades II and III.

Improved myocardial performance in infarcted rat heart by injection of disulfide-cross-linked chitosan hydrogels loaded with basic fibroblast growth factor.

Myocardial infarction (MI) has been considered as the leading cause of cardiovascular-related deaths worldwide. Basic fibroblast growth factor (bFGF) is a member of the fibroblast growth factor family that promotes angiogenesis after MI; however, it has poor clinical efficacy due to proteolytic degradation, low drug accumulation, and severe drug-induced side effects. In this study, an injectable disulfide-cross-linked chitosan hydrogel loaded with bFGF was prepared via a thiol-disulfide exchange reaction for MI treatment. The thiol-disulfide exchange reaction between pyridyl disulfide-modified carboxymethyl chitosan (CMCS-S-S-Py) and reduced BSA (rBSA) was carried out under physiological conditions (37 °C and pH 7.4). The mechanical properties of the disulfide-cross-linked chitosan hydrogel were evaluated based on the molar ratio of the pyridyl disulfide groups of CMCS-S-S-Py and the thiol groups of rBSA. The disulfide-cross-linked chitosan hydrogel showed good swelling performance, rapid glutathione-triggered degradation behavior and well-defined cell proliferation towards NIH 3T3 fibroblast cells. In the process of establishing a rat MI model, the squeezing heart method was used to make the operation more accurate and the mortality of rats was decreased by using a ventilator. The disulfide-cross-linked chitosan hydrogel loaded with bFGF (bFGF-hydrogel) was injected into a peri-infarcted area of cardiac tissue immediately following MI. Echocardiography demonstrated that the left ventricular functions were improved by the bFGF-hydrogel after 28 days of treatment. Histological results revealed that the hydrogel significantly reduced the fibrotic area of MI, and this was further improved by the bFGF-hydrogel treatment. TUNEL and immunohistochemical staining results showed that the bFGF-hydrogel had a more synergistic effect on antiapoptosis and proangiogenesis than using either bFGF or the hydrogel alone.

Spatiotemporal regulation of angiogenesis/osteogenesis emulating natural bone healing cascade for vascularized bone formation.

Engineering approaches for growth factor delivery have been considerably advanced for tissue regeneration, yet most of them fail to provide a complex combination of signals emulating a natural healing cascade, which substantially limits their clinical successes. Herein, we aimed to emulate the natural bone healing cascades by coupling the processes of angiogenesis and osteogenesis with a hybrid dual growth factor delivery system to achieve vascularized bone formation. Basic fibroblast growth factor (bFGF) was loaded into methacrylate gelatin (GelMA) to mimic angiogenic signalling during the inflammation and soft callus phases of the bone healing process, while bone morphogenetic protein-2 (BMP-2) was bound onto mineral coated microparticles (MCM) to mimics osteogenic signalling in the hard callus and bone remodelling phases. An Initial high concentration of bFGF accompanied by a sustainable release of BMP-2 and inorganic ions was realized to orchestrate well-coupled osteogenic and angiogenic effects for bone regeneration. In vitro experiments indicated that the hybrid hydrogel markedly enhanced the formation of vasculature in human umbilical vein endothelial cells (HUVECs), as well as the osteogenic differentiation of mesenchymal stem cells (BMSCs). In vivo results confirmed the optimal osteogenic performance of our F/G-B/M hydrogel, which was primarily attributed to the FGF-induced vascularization. This research presents a facile and potent alternative for treating bone defects by emulating natural cascades of bone healing.