MMP 9-instructed assembly of bFGF nanofibers in ischemic myocardium to promote heart repair

Background: The only effective treatment for myocardial infarction (MI) is the timely restoration of coronary blood flow in the infarcted area, but further reperfusion exacerbates myocardial injury and leads to distal coronary no-reflow, which affects patient prognosis. Angiogenesis could be an important therapeutic strategy for re-establishing the blood supply to save the ischemic myocardium after MI. Basic fibroblast growth factor (bFGF) has been shown to promote angiogenesis. However, direct intravenous administration of bFGF is not a viable option given its poor half-life in vivo. Methods: Herein, we developed a peptide Lys-Lys-Pro-Leu-Gly-Leu-Ala-Gly-Phe-Phe (K2) to encapsulate bFGF to form bFGF@K2 micelle and proposed an enzyme-instructed self-assembly (EISA) strategy to deliver and slowly release bFGF in the ischemic myocardium. Results: The bFGF@K2 micelle exerted a stronger cardioprotective effect than free bFGF in a rat model of myocardial ischemia-reperfusion (MI/R). In vitro results revealed that the bFGF@K2 micelle could be cleaved by matrix metallopeptidase 9 (MMP-9) to yield bFGF@Nanofiber through amphipathic changes. In vivo experiments indicated that intravenous administration of bFGF@K2 micelle could lead to their restructuring into bFGF@Nanofiber and long term retention of bFGF in the ischemic myocardium of rat due to high expression of MMP-9 and assembly-induced retention (AIR) effect, respectively. Twenty-eight days after MI/R model establishment, bFGF@K2 micelle treatment significantly reduced fibrosis and improved cardiac function of the rats. Conclusion: We predict that our strategy could be applied in clinic for MI treatment in the future.

Improved cryopreservation of in vitro produced bovine embryos using FGF2, LIF, and IGF1

In vitro embryo production systems are limited by their inability to consistently produce embryos with the competency to develop to the blastocyst stage, survive cryopreservation, and establish a pregnancy. Previous work identified a combination of three cytokines [fibroblast growth factor 2 (FGF2), leukemia inhibitory factor (LIF), and insulin-like growth factor 1 (IGF1)], called FLI, that we hypothesize improve preimplantation development of bovine embryos in vitro. To test this hypothesis, FLI was supplemented into oocyte maturation or embryo culture medium. Embryos were produced in vitro using abattoir-derived oocytes and fertilized with sperm from a single bull known to have high fertility. After an 18-20 h fertilization period, putative zygotes were cultured in synthetic oviductal fluid (SOF) for 8 days. The addition of FLI to the oocyte maturation medium increased (P < 0.05) the dissociation of transzonal projections at 12, 18, and 24 h of maturation, as well as, the proportion of oocytes that reached the metaphase II stage of meiosis. Additionally, lipid content was decreased (P < 0.05) in the blastocyst stage embryo. The addition of FLI during the culture period increased development to the blastocyst stage, cytoskeleton integrity, and survival following slow freezing, as well as, decreased post thaw cell apoptosis (P < 0.05). In conclusion, the supplementation of these cytokines in vitro has the potential to alleviate some of the challenges associated with the cryo-survival of in vitro produced bovine embryos through improving embryo development and embryo quality.

Smart Hydrogel-Based DVDMS/bFGF Nanohybrids for Antibacterial Phototherapy with Multiple Damaging Sites and Accelerated Wound Healing

Burn infection is one of the commonest causes of death in severely burned patients. Developing multifunctional biological nanomaterials has a great significance for the comprehensive treatment of burn infection. In this paper, we developed a hydrogel-based nanodelivery system with antibacterial activity and skin regeneration function, which was used for photodynamic antimicrobial chemotherapy (PACT) in the treatment of burns. The treatment system is mainly composed of porphyrin photosensitizer sinoporphyrin sodium (DVDMS) and poly(lactic-co-glycolic acid) (PLGA)-encapsulated basic fibroblast growth factor (bFGF) nanospheres that are embedded in carboxymethyl chitosan (CMCS)-sodium alginate to form CSDP hybrid hydrogel. We systematically evaluated the inherent antibacterial performance, rheological properties, fluorescence imaging, and biocompatibility of the CSDP nanosystem. Under mild photoirradiation (30 J/cm², 5 min), 10 μg/mL CSDP showed excellent antibacterial and anti-biofilm activities, which eradicated almost 99.99% of Staphylococcus aureus and multidrug-resistant (MDR) S. aureus in vitro. KEGG analysis identified that multiple signaling pathways were changed in MDR S. aureus after PACT. In the burn-infection model, CSDP-PACT successfully inhibited bacteria growth and concurrently promoted wound healing. Moreover, several regenerative factors were increased and some proinflammatory factors were reduced in the burn wounds of CSDP hydrogel treatment. These results suggest that the multifunctional CSDP hydrogel is a portable, light-triggered, antibacterial theranostic-platform and CSDP-PACT provides a promising strategy or the mechanically based synergistic treatment of burn infections.

FGF-2 Attenuates Neuronal Apoptosis via FGFR3/PI3k/Akt Signaling Pathway After Subarachnoid Hemorrhage

Neuronal apoptosis is a common and critical pathology following subarachnoid hemorrhage (SAH). We investigated the anti-apoptotic property of fibroblast growth factor (FGF)-2 after SAH in rats. A total of 289 rats underwent endovascular perforation to induce SAH or sham operation. Three dosages (3, 9, or 27 μg) of recombinant FGF-2 (rFGF-2) or vehicle was administered intranasally to rats 30 min after SAH induction. The pan-FGF receptor (FGFR) inhibitor PD173074 or vehicle was administered intracerebroventricularly (i.c.v.) 1 h before modeling, in addition to rFGF-2 treatment. Small interfering ribonucleic acid (siRNA) for FGFR1 and FGFR3 or scrambled siRNA was administered i.c.v. 48 h before SAH induction in addition to rFGF-2 treatment. Anti-FGF-2 neutralizing antibody or normal mouse immunoglobulin G (IgG) was administered i.c.v. 1 h before SAH model. Neurobehavioral tests, SAH severity, brain water content, immunofluorescence, Fluoro-Jade C, TUNEL staining, and western blot were evaluated. The expression of FGF-2, FGFR1, and FGFR3 increased after SAH. FGFR1 and FGFR3 were expressed in the neurons. Nine micrograms of FGF-2 alleviated neurological impairments, brain edema, and neuronal apoptosis following SAH. A rFGF-2 treatment improved motor skill learning and spatial memory and increased the number of surviving neurons postinjury to 28 days after SAH. PD173074 abolished the anti-apoptotic effects of rFGF-2 via suppression of the expression of PI3k, phosphorylated Akt (p-Akt), and Bcl-2 leading to enhancement of the expression of Bax. FGFR3 siRNA worsened neurobehavioral function and suppressed the expression of PI3k, p-Akt, and Bcl-2 rather than FGFR1 siRNA in SAH rats treated with rFGF-2. Anti-FGF-2 neutralizing antibody suppressed the expression of PI3k and p-Akt after SAH. FGF-2 may be a promising therapy to reduce post-SAH neuronal apoptosis via activation of the FGFR3/PI3k/Akt signaling pathway.

Modelling optimal delivery of bFGF to chronic wounds using ODEs

In this paper, we present an ordinary differential equation model depicting the interactions of basic fibroblast growth factor (bFGF) and its binding agents in a chronic wound. The delivery of bFGF was treated as a control variable and is coupled to an objective functional. By optimising the objective functional with respect to the control, predictions for optimal delivery rates of bFGF are proposed. The optimal control is then validated by comparing the cost of the objective functional for the optimal delivery rate and several alternative delivery rates. This paper addresses two objectives of effective drug delivery to chronic wounds. The first is to provide insight for the priority of delivering bFGF: to minimise the quantity of bFGF, or to optimise the distribution of bound bFGF. For effective concentrations of bound bFGF, the optimisation of bound bFGF must be prioritised over the minimisation of bFGF delivered. The second objective is to comment on the effect of the proteolytic environment within the wound, with the concentration of bound bFGF starting to decrease late in the treatment period for highly proteolytic environments. This will lead to long term complications with wound closure after the treatment has been completed. Also, it was found that for highly proteolytic environments, the cost of delivering bFGF increased. The need for optimal drug delivery is made apparent by the burden of chronic wounds on the medical industry across the developed world.

The role of FGF-2 in smoke-induced emphysema and the therapeutic potential of recombinant FGF-2 in patients with COPD

Although the positive effects of recombinant fibroblast growth factor-2 (rFGF-2) in chronic obstructive pulmonary disease (COPD) have been implicated in previous studies, knowledge of its role in COPD remains limited. The mechanism of FGF2 in a COPD mouse model and the therapeutic potential of rFGF-2 were investigated in COPD. The mechanism and protective effects of rFGF-2 were evaluated in cigarette smoke-exposed or elastase-induced COPD animal models. Inflammation was assessed in alveolar cells and lung tissues from mice. FGF-2 was decreased in the lungs of cigarette smoke-exposed mice. Intranasal use of rFGF-2 significantly reduced macrophage-dominant inflammation and alveolar destruction in the lungs. In the elastase-induced emphysema model, rFGF-2 improved regeneration of the lungs. In humans, plasma FGF-2 was decreased significantly in COPD compared with normal subjects (10 subjects, P = 0.037). The safety and efficacy of inhaled rFGF-2 use was examined in COPD patients, along with changes in respiratory symptoms and pulmonary function. A 2-week treatment with inhaled rFGF-2 in COPD (n = 6) resulted in significantly improved respiratory symptoms compared with baseline levels (P < 0.05); however, the results were not significant compared with the placebo. The pulmonary function test results of COPD improved numerically compared with those in the placebo, but the difference was not statistically significant. No serious adverse events occurred during treatment with inhaled rFGF-2. The loss of FGF-2 production is an important mechanism in the development of COPD. Inhaling rFGF-2 may be a new therapeutic option for patients with COPD because rFGF-2 decreases inflammation in lungs exposed to cigarette smoke.

Controlled release of basic fibroblast growth factor for angiogenesis using acoustically-responsive scaffolds

The clinical translation of pro-angiogenic growth factors for treatment of vascular disease has remained a challenge due to safety and efficacy concerns. Various approaches have been used to design spatiotemporally-controlled delivery systems for growth factors in order to recapitulate aspects of endogenous signaling and thus assist in translation. We have developed acoustically-responsive scaffolds (ARSs), which are fibrin scaffolds doped with a payload-containing, sonosensitive emulsion. Payload release can be controlled non-invasively and in an on-demand manner using focused, megahertz-range ultrasound (US). In this study, we investigate the in vitro and in vivo release from ARSs containing basic fibroblast growth factor (bFGF) encapsulated in monodispersed emulsions. Emulsions were generated in a two-step process utilizing a microfluidic device with a flow focusing geometry. At 2.5 MHz, controlled release of bFGF was observed for US pressures above 2.2 ± 0.2 MPa peak rarefactional pressure. Superthreshold US yielded a 12.6-fold increase in bFGF release in vitro. The bioactivity of the released bFGF was also characterized. When implanted subcutaneously in mice, ARSs exposed to superthreshold US displayed up to 3.3-fold and 1.7-fold greater perfusion and blood vessel density, respectively, than ARSs without US exposure. Scaffold degradation was not impacted by US. These results highlight the utility of ARSs in both basic and applied studies of therapeutic angiogenesis.

The effects of fibroblast growth factor-2 delivered via a Gelfoam patch on the regeneration of myringosclerotic traumatic eardrum perforations lying close to the malleus

OBJECTIVE

We evaluated the effects of fibroblast growth factor-2 (FGF-2) delivered via a Gelfoam patch on the regeneration of myringosclerotic traumatic tympanic membrane perforations (TMPs) lying close to the malleus.

STUDY DESIGN

A prospective, randomized, controlled clinical study.

SETTING

A university-affiliated teaching hospital.

SUBJECTS AND METHODS

We prospectively analyzed, in a randomized manner, the outcomes of treatment for traumatic TMPs constituting >25% of the tympanic membrane. The closure rates, closure times, and otorrhea rates were compared among patients treated via FGF-2-containing Gelfoam patches, Gelfoam patches alone, and observation only.

RESULTS

We analyzed data from 138 patients. The perforation closure rates in the FGF-2 plus Gelfoam patch, Gelfoam patch, and observation alone groups were 97.9, 89.8, and 70.7%, respectively. Both the FGF-2 plus Gelfoam and Gelfoam alone groups exhibited significantly higher closure rates than the observational group (both p<0.05).The mean closure times were 15.7±5.1, 24.8±4.9, and 35.7±9.2days in the FGF-2 plus Gelfoam patch, Gelfoam patch alone, and observation alone groups, respectively. The FGF-2 plus Gelfoam patch group exhibited a significantly shorter closure time than the Gelfoam patch alone and observation alone groups (p<0.05). The incidences of purulent otorrhea were 14.6, 6.1, and 4.9% in the FGF-2 plus Gelfoam patch, Gelfoam patch alone, and observation alone groups, respectively. Surprisingly, 7 of 7 (100.0%) perforations associated with purulent otorrhea completely closed in the FGF-2 plus Gelfoam patch group; however, no such perforation healed in either the Gelfoam alone or observation alone group.

CONCLUSIONS

FGF-2 plus Gelfoam patching significantly shortened the closure time compared to observation and Gelfoam patching alone, and it significantly improved the closure rate (compared to observation alone) of myringosclerotic perforations lying close the malleus. FGF-2 plus Gelfoam patching is a valuable, minimally invasive alternative treatment that may be readily applied to outpatient settings.

A comparative study to evaluate the efficacy of EGF, FGF-2, and 0.3% (w/v) ofloxacin drops on eardrum regeneration

BACKGROUND

Traumatic tympanic membrane perforations (TMPs) tend to spontaneous healing, however, large TMPs usually fail to healing. Clinical and experimental studies had demonstrated that growth factors accelerated the healing of large TMPs. The aim of this study was to compare the effects of growth factors and 0.3% (w/v) ofloxacin drops n the healing of human large TMPs.

METHODS

A total of 184 human large traumatic TMPs were randomly assigned to receive epidermal growth factor (EGF) treatment, fibroblast growth factor-2 (FGF-2) treatment, 0.3% (w/v) ofloxacin drops treatment, and conservative observation (only).

RESULTS

A total of 180 patients were analyzed in this study at the 6-month follow-up. The closure rates of the perforations in the EGF, FGF-2, 0.3% (w/v) ofloxacin drops, and conservative observation groups were 91.11%, 93.18%, 95.65%, and 82.22%, respectively, the closure rates did not significantly differ among the groups (P = .165). Similarly, pairwise comparisons did not reveal any significant between-group differences (P > .0083). However, the difference of the mean closure time was significant among the 4 groups (P < .001), pairwise comparisons showed that closure time was significantly longer in the observational group than in the other 3 groups (P < .001). Nevertheless, no significant difference in mean closure time was evident between any 2 treated groups (P > .0083). The mean hearing gain after 6 months was 11.49 ± 5.88 dB for the EGF group, 10.89 ± 5.16 dB for the FGF-2 group, 10.54 ± 5.56 dB for the ofloxacin group, and 9.29 ± 5.36 dB for the observation group. Differences in hearing improvement rates among the 4 groups were not statistically significant (P = .283).

CONCLUSION

Epidermal growth factor, FGF-2, and 0.3% (w/v) ofloxacin drops accelerated the closure of large TMPs compared with conservative treatment. Surprisingly, neither the closure rate nor closure time differed significantly among the 3 treated groups. Further experimental studies to demonstrate whether 0.3% (w/v) ofloxacin per se accelerates the healing of TMPs will be interesting in the future.

Gelatin device for the delivery of growth factors involved in endochondral ossification

Controlled release drug delivery systems are well established as oral and implantable dosage forms. However, the controlled release paradigm can also be used to present complex soluble signals responsible for cellular organization during development. Endochondral ossification (EO), the developmental process of bone formation from a cartilage matrix is controlled by several soluble signals with distinct functions that vary in structure, molecular weight and stability. This makes delivering them from a single vehicle rather challenging. Herein, a gelatin-based delivery system suitable for the delivery of small molecules as well as recombinant human (rh) proteins (rhWNT3A, rhFGF2, rhVEGF, rhBMP4) is reported. The release behavior and biological activity of the released molecules was validated using analytical and biological assays, including cell reporter systems. The simplicity of fabrication of the gelatin device should foster its adaptation by the diverse scientific community interested in interrogating developmental processes, in vivo.

The N-butyl alcohol extract from Hibiscus rosa-sinensis L. flowers enhances healing potential on rat excisional wounds

ETHNO-PHARMACOLOGICAL RELEVANCE

Hibiscus rosa-sinensis L. (HRS), a folk medicine named Zhujin in China, possess anti-tumor, antioxidant, antibacterial, low density lipoprotein oxidation prevention and macrophage death prevention effects. The leaves and red flowers of HRS have been traditionally used to treat with furuncle and ulceration.

AIM OF THE STUDY

To investigate the efficacy and possible mechanism of the N-butyl alcohol extract of HRS (NHRS) red flowers in wound healing by analyzing the collagen fiber deposition, angiogenic activity and macrophages action of the NHRS.

MATERIALS AND METHODS

In an excisional wound healing model in rats, different concentrations of NHRS, or recombinant bovine basic fibroblast growth factor (rbFGF), were respectively applied twice daily for 9 days. Histopathology was assessed on day 9 via hematoxylin and eosin (HE) and Masson's trichrome (MT) staining, and immunohistochemistry for vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1) and CD68. Immunomodulation by NHRS was evaluated by a carbon clearance test in mice.

RESULTS

Wound healing post-surgery was greater in the rbFGF-control, NHRS-M and MHRS-H groups than in the model and 5% dimethylsulfoxide (DMSO)-control groups after the third day. By the sixth day the wound contraction of NHRS-M and MHRS-H groups was much higher than the rbFGF-control group. HE and MT staining revealed that epithelialization, fibroblast distribution, collagen deposition of NHRS-M- and NHRS-H-control groups were significantly higher than the model group. Moreover, immunohistochemistry showed more intense staining of VEGF, TGF-β1 and CD68 in the rbFGF- and NHRS-control groups, compared to that in model and 5% DMSO-control groups. The clearance and phagocytic indices of NHRS-M- and NHRS-H-control groups were significantly higher than that of the carboxyl methyl cellulose (CMC) group in mice.

CONCLUSION

NHRS accelerates wound repair via enhancing the macrophages activity, accelerating angiogenesis and collagen fiber deposition response mediated by VEGF and TGF-β1.

Multifactorial Optimizations for Directing Endothelial Fate from Stem Cells

Embryonic stem cells (ESC) and induced pluripotent stem (iPS) cells are attractive in vitro models of vascular development, therapeutic angiogenesis, and tissue engineering. However, distinct ESC and iPS cell lines respond differentially to the same microenvironmental factors. Developing improved/optimized differentiation methodologies tailored/applicable in a number of distinct iPS and ESC lines remains a challenge in the field. Currently published methods for deriving endothelial cells (EC) robustly generate high numbers of endothlelial progenitor cells (EPC) within a week, but their maturation to definitive EC is much more difficult, taking up to 2 months and requiring additional purification. Therefore, we set out to examine combinations/levels of putative EC induction factors—utilizing our stage-specific chemically-defined derivation methodology in 4 ESC lines including: kinetics, cell seeding density, matrix signaling, as well as medium treatment with vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF). The results indicate that temporal development in both early and late stages is the most significant factor generating the desired cells. The generation of early Flk-1⁺/KDR⁺ vascular progenitor cells (VPC) from pluripotent ESC is directed predominantly by high cell seeding density and matrix signaling from fibronectin, while VEGF supplementation was NOT statistically significant in more than one cell line, especially with fibronectin matrix which sequesters autocrine VEGF production by the differentiating stem cells. Although some groups have shown that the GSK3-kinase inhibitor (CHIR) can facilitate EPC fate, it hindered the generation of KDR+ cells in our preoptimized medium formulations. The methods summarized here significantly increased the production of mature vascular endothelial (VE)-cadherin+ EC, with up to 93% and 57% purity from mouse and human ESC, respectively, before VE-cadherin+ EC purification.

A shear-thinning hydrogel that extends in vivo bioactivity of FGF2

We designed and tested a versatile hydrogel for tissue regeneration by preserving the bioactivity of growth factors. The shear-thinning gel self-assembles within 1 min from heparin and Laponite-a silicate nanoparticle, thus the name HELP gel. By not covalently modifying heparin, it should retain its natural affinity towards many proteins anchored in the extracellular matrix. In principle, HELP gel can bind any heparin-binding growth factor; we use fibroblast growth factor-2 (FGF2) in this study to demonstrate its utility. Heparin in the gel protects FGF2 from proteolytic degradation and allows it to be released over time with preserved bioactivity. FGF2 released from subcutaneously injected gel induces strong angiogenesis in a mouse model. The hydrogel degrades completely in vivo in 8 weeks with or without growth factors, eliciting mild inflammatory response but having little impacts on the surrounding tissue. The ease of preparation and scale-up makes this protein delivery platform attractive for clinical translation.

Application of a Collagenated Biphasic Calcium Phosphate Loaded with Fibroblast Growth Factor-2 in the Rabbit Sinus: A Pilot Study

PURPOSE

The aim of this study was to determine the effect of collagenated biphasic calcium phosphate (CBCP) loaded with fibroblast growth factor-2 (FGF-2) on bone regeneration in a rabbit sinus model.

MATERIALS AND METHODS

Bilateral sinus augmentations were performed using either FGF-2-loaded CBCP (FGF-2 group) or CBCP only (control group) in 10 rabbits. The experimental animals were euthanized at 2 weeks (n = 5) or 4 weeks (n = 5) postoperatively. Volumetric analyses were done by means of microcomputed tomography and histomorphometry.

RESULTS

The volumes of total augmentation, new bone, residual material, and fibrovascular tissue were significantly greater in the FGF-2 group than in the control group at 2 weeks, but the differences between the two groups had disappeared by 4 weeks. Histologically, the healing patterns, such as new bone formation and the resorption of residual material, did not differ notably between the two groups. The results of the histometric analysis did not correspond to those of the volumetric analysis. The areas of total augmentation, new bone, residual material, and fibrovascular tissue, and the number of blood vessels did not differ significantly between the FGF-2 and the control groups at either time point.

CONCLUSION

CBCP loaded with FGF-2 resulted in the early promotion of new bone; however, it failed to produce superior bone regeneration in a later stage of healing.

In vitro stress effect on degradation and drug release behaviors of basic fibroblast growth factor--poly(lactic-co-glycolic-acid) microsphere

OBJECTIVE

To study the degradation and basic fibroblast growth factor (bFGF) release activity of bFGF - poly(lactic-co-glycolic-acid) microsphere (bFGF-PLGA MS) under stress in vitro, including the static pressure and shearing force-simulating mechanical environment of the joint cavity.

METHOD

First, bFGF-PLGA MSs were created. Meanwhile, two self-made experimental instruments (static pressure and shearing force loading instruments) were initially explored to provide stress-simulating mechanical environment of the joint cavity. Then, bFGF-PLGA MSs were loaded into the two instruments respectively, to study microsphere degradation and drug release experiments. In the static pressure loading experiment, normal atmospheric pressure loading (approximately 0.1 MPa), 0.35 MPa, and 4.0 MPa pressure loading and shaking flask oscillation groups were designed to study bFGF-PLGA MS degradation and bFGF release. In the shearing force loading experiment, a pulsating pump was used to give the experimental group an output of 1,000 mL/min and the control group an output of 10 mL/min to carry out bFGF-PLGA MS degradation and drug release experiments. Changes of bFGF-PLGA MSs, including microsphere morphology, quality, weight-average molecular weight of polymer, and microsphere degradation and bFGF release, were analyzed respectively.

RESULTS

In the static pressure loading experiment, bFGF-PLGA MSs at different pressure were stable initially. The trend of molecular weight change, quality loss, and bFGF release was consistent. Meanwhile, microsphere degradation and bFGF release rates in the 4.0 MPa pressure loading group were faster than those in the normal and 0.35 MPa pressure loading groups. It was the fastest in the shaking flask group, showing a statistically significant difference (P<0.0001). In the shearing force loading experiment, there were no distinctive differences in the rates of microsphere degradation and bFGF release between experimental and control group. Meanwhile, microsphere degradation and bFGF release rates by shaking flask oscillation were obviously faster than those by shearing force only (P<0.0001).

CONCLUSION

There are significant effects on bFGF-PLGA MS degradation and bFGF release due to the interaction between extraction stress and time. Static pressure has a conspicuous influence on bFGF-PLGA MS degradation and release, especially at a pressure of 4.0 MPa. The shearing force has a slight effect on bFGF-PLGA MS degradation and drug release. On the contrary, shaking flask oscillation has a significantly distinctive effect.

Priming Dental Pulp Stem Cells With Fibroblast Growth Factor-2 Increases Angiogenesis of Implanted Tissue-Engineered Constructs Through Hepatocyte Growth Factor and Vascular Endothelial Growth Factor Secretion

Tissue engineering strategies based on implanting cellularized biomaterials are promising therapeutic approaches for the reconstruction of large tissue defects. A major hurdle for the reliable establishment of such therapeutic approaches is the lack of rapid blood perfusion of the tissue construct to provide oxygen and nutrients. Numerous sources of mesenchymal stem cells (MSCs) displaying angiogenic potential have been characterized in the past years, including the adult dental pulp. Establishment of efficient strategies for improving angiogenesis in tissue constructs is nevertheless still an important challenge. Hypoxia was proposed as a priming treatment owing to its capacity to enhance the angiogenic potential of stem cells through vascular endothelial growth factor (VEGF) release. The present study aimed to characterize additional key factors regulating the angiogenic capacity of such MSCs, namely, dental pulp stem cells derived from deciduous teeth (SHED). We identified fibroblast growth factor-2 (FGF-2) as a potent inducer of the release of VEGF and hepatocyte growth factor (HGF) by SHED. We found that FGF-2 limited hypoxia-induced downregulation of HGF release. Using three-dimensional culture models of angiogenesis, we demonstrated that VEGF and HGF were both responsible for the high angiogenic potential of SHED through direct targeting of endothelial cells. In addition, FGF-2 treatment increased the fraction of Stro-1+/CD146+ progenitor cells. We then applied in vitro FGF-2 priming to SHED before encapsulation in hydrogels and in vivo subcutaneous implantation. Our results showed that FGF-2 priming is more efficient than hypoxia at increasing SHED-induced vascularization compared with nonprimed controls. Altogether, these data demonstrate that FGF-2 priming enhances the angiogenic potential of SHED through the secretion of both HGF and VEGF.

The incorporation of bFGF mediated by heparin into PCL/gelatin composite fiber meshes for guided bone regeneration

The concept of guided bone regeneration facilitated by barrier membranes has been widely considered to achieve enhanced bone healing in maxillofacial surgery. However, the currently available membranes are limited in their active regulation of cellular activities. In this study, we fabricated polycaprolactone/gelatin composite electrospun nanofibers incorporated with basic fibroblast growth factor (bFGF) to direct bone regeneration. The fibrous morphology was maintained after the crosslinking and subsequent conjugation of heparin. Release of bFGF from electrospun nanofibers without heparin resulted in a spontaneous burst, while the heparin-mediated release of bFGF decreased the burst release in 24 h. The bFGF released from the nanofibers enhanced the proliferation and migration of human mesenchymal stem cells as well as the tubule formation of human umbilical cord blood cells. The subcutaneous implantation of fibers incorporated with bFGF mobilized a large number of cells positive for CD31 and smooth muscle alpha actin within 2 weeks. The effect of the nanofibers incorporated with bFGF on bone regeneration was evaluated on a calvarial critical size defect model. As compared to the mice that received fibers without bFGF, which presented minimal new bone formation (5.36 ± 3.4 % of the defect), those that received implants of heparinized nanofibers incorporated with 50 or 100 ng/mL bFGF significantly enhanced new bone formation (10.82 ± 2.2 and 17.55 ± 6.08 %). Taken together, our results suggest that the electrospun nanofibers incorporating bFGF have the potential to be used as an advanced membrane that actively enhances bone regeneration.

The Rabbit Corneal Pocket Assay

The rabbit corneal micropocket angiogenesis assay uses the avascular cornea as a substrate canvas to study angiogenesis in vivo. Through the use of standardized slow-release pellets, a predictable angiogenic response is generated over the course of 1-2 weeks and then quantified. Uniform slow-release pellets are prepared by mixing purified angiogenic growth factors such as basic fibroblast growth factor or vascular endothelial growth factor and a synthetic polymer to allow slow release. A micropocket is surgically created in the rabbit cornea under anesthesia and a pellet implanted. On the days later, the angiogenic response is measured and qualified using a slit lamp, as well as the concomitant vascular phenotype or inflammatory features. The results of the assay are used to assess the ability of potential therapeutic molecules to modulate angiogenesis in vivo, both when released locally or given by ocular formulations or through systemic treatment. In this chapter, the experimental details of the rabbit cornea assay and technical implementations to the original protocol are described.

bFGF and VEGF improve the quality of vitrified-thawed human ovarian tissues after xenotransplantation to SCID mice

PURPOSE

The aim of this research is to study whether basic fibroblast growth factor (bFGF) alone or in combination with vascular endothelial growth factor (VEGF) could improve the quality of vitrified-thawed human ovarian tissue xenotransplanted to severe combined immune deficiency (SCID) mice.

METHODS

After collection and cryopreservation, thawed human ovarian tissue were cultured in vitro for 2 days and then xenografted to severe combined immune deficiency (SCID) mice for 7 days. The in vitro culture medium was separated into six groups, including (A) the blank control group, (B) the human recombinant bFGF (150 ng/ml) group, (C) the bFGF (150 ng/ml)+human recombinant VEGF (25 ng/ml) group, (D) bFGF (150 ng/ml)+VEGF (50 ng/ml) group, (E) bFGF (150 ng/ml)+ VEGF (75 ng/ml) group and (F) bFGF (150 ng/ml) + VEGF (100 ng/ml) group. In addition, eight pieces of thawed ovarian tissue were transplanted without in vitro culture, which serve as the fresh control group. The effect of transplantation was assessed by histological analysis, immunohistochemical staining for CD34, Ki-67, and AC-3 expression, and microvessel density (MVD).

RESULTS

There was no significant difference between the fresh and blank control group. Compared to the blank control group, the number of follicles, MVD, and rate of Ki-67-positive cells increased significantly in groups B, C, D, E, and F, while apoptosis decreased significantly. Compared to the bFGF treatment group, no significant difference appeared in group C, D, E, and F.

CONCLUSIONS

The administration of bFGF alone or in combination with VEGF improved the quality of postgraft human ovarian tissue, though VEGF, regardless of different concentrations, did not influence effect of bFGF.

Controlled dual delivery of fibroblast growth factor-2 and Interleukin-10 by heparin-based coacervate synergistically enhances ischemic heart repair

Myocardial infarction (MI) causes myocardial necrosis, triggers chronic inflammatory responses, and leads to pathological remodeling. Controlled delivery of a combination of angiogenic and immunoregulatory proteins may be a promising therapeutic approach for MI. We investigated the bioactivity and therapeutic potential of an injectable, heparin-based coacervate co-delivering an angiogenic factor, fibroblast growth factor-2 (FGF2), and an anti-inflammatory cytokine, Interleukin-10 (IL-10) in a spatially and temporally controlled manner. Coacervate delivery of FGF2 and IL-10 preserved their bioactivities on cardiac stromal cell proliferation in vitro. Upon intramyocardial injection into a mouse MI model, echocardiography revealed that FGF2/IL-10 coacervate treated groups showed significantly improved long-term LV contractile function and ameliorated LV dilatation. FGF2/IL-10 coacervate substantially augmented LV myocardial elasticity. Additionally, FGF2/IL-10 coacervate notably enhanced long-term revascularization, especially at the infarct area. In addition, coacervate loaded with 500 ng FGF2 and 500 ng IL-10 significantly reduced LV fibrosis, considerably preserved infarct wall thickness, and markedly inhibited chronic inflammation at the infarct area. These results indicate that FGF2/IL-10 coacervate has notably greater therapeutic potential than coacervate containing only FGF2. Overall, our data suggest therapeutically synergistic effects of FGF-2/IL-10 coacervate, particularly coacervate with FGF2 and 500 ng IL-10, for the treatment of ischemic heart disease.

Human Urine-derived Stem Cells Seeded Surface Modified Composite Scaffold Grafts for Bladder Reconstruction in a Rat Model

We conducted this study to investigate the synergistic effect of human urine-derived stem cells (USCs) and surface modified composite scaffold for bladder reconstruction in a rat model. The composite scaffold (Polycaprolactone/Pluronic F127/3 wt% bladder submucosa matrix) was fabricated using an immersion precipitation method, and heparin was immobilized on the surface via covalent conjugation. Basic fibroblast growth factor (bFGF) was loaded onto the heparin-immobilized scaffold by a simple dipping method. In maximal bladder capacity and compliance analysis at 8 weeks post operation, the USCs-scaffold(heparin-bFGF) group showed significant functional improvement (2.34 ± 0.25 mL and 55.09 ± 11.81 µL/cm H2O) compared to the other groups (2.60 ± 0.23 mL and 56.14 ± 9.00 µL/cm H2O for the control group, 1.46 ± 0.18 mL and 34.27 ± 4.42 µL/cm H2O for the partial cystectomy group, 1.76 ± 0.22 mL and 35.62 ± 6.69 µL/cm H2O for the scaffold group, and 1.92 ± 0.29 mL and 40.74 ± 7.88 µL/cm H2O for the scaffold(heparin-bFGF) group, respectively). In histological and immunohistochemical analysis, the USC-scaffold(heparin-bFGF) group showed pronounced, well-differentiated, and organized smooth muscle bundle formation, a multi-layered and pan-cytokeratin-positive urothelium, and high condensation of submucosal area. The USCs seeded scaffold(heparin-bFGF) exhibits significantly increased bladder capacity, compliance, regeneration of smooth muscle tissue, multi-layered urothelium, and condensed submucosa layers at the in vivo study.

Autologous fat augmentation of the vocal fold with basic fibroblast growth factor: Computed tomographic assessment of fat tissue survival after augmentation

CONCLUSION

The volume of fat tissue loss after vocal fold augmentation can be decreased when augmentation is performed with addition of basic fibroblast growth factor (b-FGF).

OBJECTIVES

The effectiveness of augmentation is easily decreased due to absorption. Canine experiments have confirmed that the decreased effectiveness caused by absorption after augmentation can be reduced by administering low-concentration b-FGF. Clinical application was trialed after acquiring approval from the institutional clinical review committee.

METHOD

Autologous fat tissue with b-FGF was injected into the vocal folds in cases of unilateral vocal cord paralysis. This study compared fat tissue survival after injection by assessing images from computed tomography (CT).

RESULTS

Assessments using CT revealed that the decrease in volume of injected fat tissue was smaller in cases treated using b-FGF than in cases using the conventional method. No severe complications were encountered using this method.

[EFFECT OF BONE MARROW MESENCHYMAL STEM CELLS ON GASTRIC ULCER REPAIRING]

OBJECTIVE

To explore the ettect and mechanisms of bone marrow mesenchymal stem cells (BMSCs) on healing quality of acetic acid-induced gastric ulcer.

METHODS

Forty-eight clean grade male Wistar rats were used to establish the model of gastric ulcer with acetic acid and were randomly divided into 3 groups after 3 days of modeling, 16 rats each group. After the abdominal cavity was open and stomach was pulled out, no treatment was given in group A, 150 µL phosphate buffered saline (PBS) and 150 µL BMSCs at passage 4+PBS (1 x 10(8) cells/100 µL) were injected into the gastric wall surrounding the ulcer at 5 different points in groups B and C respectively. After 10 days, the ulcer area was measured, the mucosal thickness and the number of dilated glands were tested in the regenerative mucosa by histological method. And the expression of vascular endothelial growth factor (VEGF) was detected at ulcerative margin by immunohistochemical method.

RESULTS

The ulcer area in group C was significantly smaller than that of groups A and B (P < 0.01), but no significant difference was found between groups A and B (P > 0.05). HE staining showed that group C had thicker regenerative gastric mucosa, less dilated glands, and more regular mucosal structure than groups A and B, showing significant differences in regenerative gastric mucosa thickness and dilated glands number (P < 0.01), but no significant difference between groups A and B (P > 0.05). Immunohistochemical staining showed that the positive expression of VEGF in the ulcer margin mucosa of group C was significantly higher than that of groups A and B. The integral absorbance (IA) value of VEGF expression in group C was significantly higher than that in groups A and B (P < 0.01), but no significant difference between groups A and B (P > 0.05).

CONCLUSION

BMSCs can accelerate ulcer healing by the secretion of VEGF, and improve the quality of ulcer healing.

Evaluation of the optimum time for direct application of fibroblast growth factor to human traumatic tympanic membrane perforations

OBJECTIVE

The aim of this study was to determine the optimum time for direct application of basic fibroblast growth factor (bFGF) on large traumatic tympanic membrane perforations (TMPs).

STUDY DESIGN

Prospective clinical study.

SETTING

Tertiary University Hospital.

METHODS

Ninety-three patients, with traumatic TMPs greater in extent than 25% of the entire tympanic membrane, were randomized into observation and bFGF-treated groups (~0.2-0.25 mL of bFGF solution was applied directly onto the TM once daily and continued until the perforation closed). Initial visit times were subcategorized into perforation durations of ≤3 and >3 days, thereby rendering two subgroups, as follows: A and B in the observation group; and C and D in the bFGF-treated group. The closure rate and mean closure time were evaluated after 6 months.

RESULTS

Eighty-six patients were finally analyzed. After 6 months, the bFGF-treated group exhibited a significantly higher total closure rate (97.8 versus 82.5%, p < 0.05) and a shorter mean closure time (12.5 ± 3.4 versus 34.0 ± 5.9 days, p < 0.05) compared with the spontaneous healing group. In addition, in the observation group, visiting time was not associated with differences in closure rate (p > 0.05) and mean closure time (p > 0.05), between the A and B subgroups. Similarly, in the bFGF-treated group, visiting time was not associated with differences in closure rate (p > 0.05) between the C and D subgroups. However, the D subgroup was characterized by significantly shortened mean closure time compared with the C subgroup (p < 0.05).

CONCLUSIONS

This study shows the beneficial effect of bFGF on human traumatic large TMPs when applied after the 3rd day post-injury had passed (i.e. during the proliferative stage of wound healing). The procedure can not only significantly shorten closure time but can also reduce both the clinical administration duration and occurrence of side-effects associated with bFGF.

L-ascorbic acid 2-phosphate and fibroblast growth factor-2 treatment maintains differentiation potential in bone marrow-derived mesenchymal stem cells through expression of hepatocyte growth factor

l-ascorbic acid 2-phosphate (Asc-2P) acts as an antioxidant and a stimulator of hepatocyte growth factor (HGF) production. Previously, we reported that depletion of growth factors such as fibroblast growth factor (FGF)-2, epidermal growth factor (EGF), FGF-4 and HGF during serial passage could induce autophagy, senescence and down-regulation of stemness (proliferation via FGF-2/-4 and differentiation via HGF). In this study, we investigated the proliferation and differentiation potential of BMSCs by FGF-2 and Asc-2P. Co-treatment with FGF-2 and Asc-2P induced optimal proliferation of BMSCs and increased the accumulation rate of BMSC numbers during a 2-month culture period. Moreover, differentiation potential was maintained by co-treatment with FGF-2 and Asc-2P via HGF expression. Adipogenic differentiation potential by FGF-2 and Asc-2P was dramatically suppressed by c-Met inhibitors (SU11274). These data suggest that co-treatment with FGF-2 and Asc-2P would be beneficial in obtaining BMSCs that possess "stemness" during long-term culture.

Systemically administered brain-targeted nanoparticles transport peptides across the blood-brain barrier and provide neuroprotection

Although growth factors and anti-apoptotic peptides have been shown to be neuroprotective in stroke models, translation of these experimental findings to clinic is hampered by limited penetration of peptides to the brain. Here, we show that a large peptide like the basic fibroblast growth factor (bFGF) and a small peptide inhibitor of caspase-3 (z-DEVD-FMK) can effectively be transported to the brain after systemic administration by incorporating these peptides to brain-targeted nanoparticles (NPs). Chitosan NPs were loaded with peptides and then functionalized by conjugating with antibodies directed against the transferrin receptor-1 on brain endothelia to induce receptor-mediated transcytosis across the blood-brain barrier (BBB). Pre-ischemic systemic administration of bFGF- or z-DEVD-FMK-loaded NPs significantly decreased the infarct volume after 2-hour middle cerebral artery occlusion and 22-hour reperfusion in mice. Co-administration of bFGF- or z-DEVD-FMK-loaded NPs reduced the infarct volume further and provided a 3-hour therapeutic window. bFGF-loaded NPs were histologically detected in the brain parenchyma and also restored ischemia-induced Akt dephosphorylation. The neuroprotection was not observed when receptor-mediated transcytosis was inhibited with imatinib or when bFGF-loaded NPs were not conjugated with the targeting antibody, which enables them to cross the BBB. Nanoparticles targeted to brain are promising drug carriers to transport large as well as small BBB-impermeable therapeutics for neuroprotection against stroke.

Comparison between subcutaneous injection of basic fibroblast growth factor-hydrogel and intracavernous injection of adipose-derived stem cells in a rat model of cavernous nerve injury

OBJECTIVE

To compare the effects of subcutaneous penile injection of basic fibroblast growth factor (bFGF)-hydrogel and intracavernous injection of human adipose-derived stem cells (h-ADSCs) on improving erectile function in a rat model of cavernous nerve injury.

MATERIALS AND METHODS

Adult male Sprague-Dawley rats were randomly divided into 5 groups (n = 10 per group): age-matched control (normal group), bilateral cavernous nerve injury (BCNI group), penile subcutaneous injection of hydrogel after BCNI (hydrogel group), penile subcutaneous injection of bFGF-hydrogel after BCNI (bFGF-hydrogel group) and intracavernous injection of h-ADSCs after BCNI (ADSC group). Four weeks after the treatment, all rats underwent an erectile function test. Then, penile tissue was harvested for immunohistological analysis of bFGF, phalloidin, and cluster of differentiation (CD) 31. The cyclic guanosine monophosphate (cGMP) level of the corpus cavernosum was quantified by cGMP assay.

RESULTS

From the functional test and immunohistological result, we observed that bFGF-hydrogel and h-ADSCs injection significantly elevated intracavernous pressure. The evaluation of filamentous actin content, CD31 expression, and cGMP concentration in the corpus cavernosum were meaningfully increased in the bFGF-hydrogel and ADSC groups compared with BCNI group. The bFGF released from bFGF-hydrogel prevented smooth muscle atrophy. Moreover, bFGF expression was significantly increased in bFGF-hydrogel group.

CONCLUSION

The subcutaneous injection of bFGF-hydrogel prevented smooth muscle atrophy, increased the intracavernous pressure, and improved erectile function like an intracavernous injection of h-ADSCs.

Effects of basic fibroblast growth factor dose on traumatic tympanic membrane perforation

OBJECTIVE

To compare the healing outcomes of higher and lower doses of basic fibroblast growth factor (bFGF) on human traumatic tympanic membrane perforation (TMP).

STUDY DESIGN

Prospective clinical study.

METHODS

All patients with traumatic TMP were treated by direct application of bFGF, and were sequentially allocated into one of two groups: lower-dose group (2-3 drops of bFGF solution daily, approximately 0.1-0.15 mL) and higher-dose group (5-6 drops of bFGF solution daily, approximately 0.25-0.3 mL). The results of closure rate, closure time, and rate of otorrhea between the higher- and lower-dose groups were compared at 3 months.

RESULTS

In total, 126 patients were included in this study. The higher-dose group showed significantly improved purulent otorrhea rate compared with the lower-dose group (p < 0.01) for perforations of the same size, although the closure rate of the middle-sized perforations did not differ significantly between higher- and lower-dose groups (p > 0.05). However, the lower-dose group had a significantly shorter closure time of 5 d compared with the higher-dose group (p < 0.05). In addition, although the lower-dose group showed shorter healing times (about 3 d) compared to the higher-dose group for large-sized perforations, the dosage of bFGF did not significantly affect the large-sized perforation closure rate (p > 0.05) or closure time (p > 0.05). Nine large-sized perforations with secondary purulent otorrhea achieved complete closure, with closure times of 7-25 (14.2 ± 5.8) d.

CONCLUSION

This study suggested that continued daily application of a lower dose of bFGF not only shortens the closure time of human traumatic TMP but also avoids secondary purulent otorrhea.

[Effects of leukemia inhibitory factor combined with basic fibroblast growth factor on proliferation and differentiation of human bone marrow mesenchymal stem cells]

OBJECTIVE

To study the effects of leukemia inhibitory factor (LIF) and basic fibroblast growth factor (bFGF) on the proliferation and differentiation of human bone marrow mesenchymal stem cells (hBMSCs).

METHODS

hBMSCs at passage 4 were divided into 4 groups according to different culture conditions: cells were treated with complete medium (a-MEM containing 10%FBS, group A), with complete medium containing 10 ng/mL LIF (group B), with complete medium containing 10 ng/mL bFGF (group C), and with complete medium containing 10 ng/mL LIF and 10 ng/mL bFGF (group D). The growth curves of hBMSCs at passage 4 in different groups were assayed by cell counting kit 8; cellular morphologic changes were observed under inverted phase contrast microscope; the surface markers of hBMSCs at passage 8 including CD44, CD90, CD19, and CD34 were detected by flow cytometry.

RESULTS

The cell growth curves of each group were similar to the S-shape; the cell proliferation rates in 4 groups were in sequence of group D > group C > group B > group A. Obvious senescence and differentiation were observed very early in group A, cells in group B maintained good cellular morphology at the early stage, with slow proliferation and late senescence; a few cells in group C differentiated into nerve-like cells, with quick proliferation; and the cells in group D grew quickly and maintained cellular morphology of hBMSCs. The expressions of CD44 and CD90 in groups A and C at passage 8 cells were lower than those of groups B and D; the expressions of CD19 and CD34 were negative in 4 groups, exhibiting no obvious difference between groups.

CONCLUSION

LIF combined with bFGF can not only maintain multiple differentiation potential ofhBMSCs, but also promote proliferation of hBMSCs.

Delivery of basic fibroblast growth factors from heparinized decellularized adipose tissue stimulates potent de novo adipogenesis

Scaffolds based on decellularized adipose tissue (DAT) are gaining popularity in adipose tissue engineering due to their high biocompatibility and adipogenic inductive property. However, previous studies involving DAT-derived scaffolds have not fully revealed their potentials for in vivo adipose tissue construction. With the aim of developing a more efficient adipose tissue engineering technique based on DAT, in this study, we investigated the in vivo adipogenic potential of a basic fibroblast growth factor (bFGF) delivery system based on heparinized DAT (Hep-DAT). To generate this system, heparins were cross-linked to mouse DATs by using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide and N-Hydroxysuccinimide. The bFGF-binding Hep-DATs were first tested for controlled release ability in vitro and then transplanted subcutaneously. Highly vascularized adipose tissues were formed 6weeks after transplantation. Histology and gene expression analysis revealed that majority of the Hep-DAT scaffolds were infiltrated with host-derived adipose tissues that possessed similar adipogenic and inflammatory gene expression as endogenous adipose tissues. Additionally, strong de novo adipogenesis could also be induced when bFGF-binding Hep-DATs were thoroughly minced and injected subcutaneously. In conclusion, our study demonstrated that bFGF-binding Hep-DAT could be an efficient, biocompatible and injectable adipogenic system for in vivo adipose tissue engineering.

FGF2 delays tectal neurogenesis, increases tectal cell numbers, and alters tectal lamination in embryonic chicks

Intraventricular injections of the fibroblast growth factor 2 (FGF2) are known to increase the size of the optic tectum in embryonic chicks. Here we show that this increase in tectum size is due to a delay in tectal neurogenesis, which by definition extends the proliferation of tectal progenitors. Specifically, we use cumulative labeling with the thymidine analog EdU to demonstrate that FGF2 treatment on embryonic day 4 (ED4) reduces the proportion and absolute number of unlabeled cells in the rostroventral tectum when EdU infusions are begun on ED5, as one would expect if FGF2 retards tectal neurogenesis. We also examined FGF2′s effect on neurogenesis in the caudodorsal tectum, which is born 2-3 days after the rostroventral tectum, by combining FGF2 treatment on ED4 with EDU infusions beginning on ED8. Again, FGF2 treatment reduced the proportion and number of EdU-negative (i.e., unlabeled) cells, consistent with a delay in neurogenesis. Collectively, these data indicate FGF2 in embryonic chicks delays neurogenesis throughout much of the tectum and continues to do so for several days after the FGF2 injection. One effect of this delay in neurogenesis is that tectal cell numbers more than double. In addition, tectal laminae that are born early in development become abnormally thin and cell-sparse after FGF2 treatment, whereas late-born layers remain unaffected. Combined with the results of prior work, these data indicate that FGF2 delays tectal neurogenesis and, thereby, triggers a cascade of changes in tectum size and morphology.

Quantitative evaluation of myofibroblast apoptosis during wound healing in rat palate after post-operative administration of basic fibroblast growth factor (bFGF)

OBJECTIVE

Excessive wound contraction apparently inhibits maxillary growth; thus, myofibroblast apoptosis needs to be accelerated in mucoperiosteal denudation after palatoplasty. The aim of this study was to evaluate myofibroblast apoptosis during wound healing in mucoperiosteal denudation of rat palates immediately after post-operative administration of basic fibroblast growth factor (bFGF).

MATERIALS AND METHODS

A total of 100 male Wistar rats aged 20 days were divided into control, scar, sham and bFGF groups (n = 25 each). In the scar, sham and bFGF groups, mucoperiosteum was removed from the palate and fibrin glue was applied to the exposed bone surface immediately after surgery. In the bFGF group, 10 μL of 2 μg/μL bFGF solution was injected into the operated area beneath the fibrin glue. At 2, 5, 7, 14 and 28 days post-operatively, myofibroblast apoptosis during the wound healing process was investigated by double immunofluorescence staining. The apoptotic area of myofibroblasts was measured using image software.

RESULTS

In the bFGF group, at 2 days, apoptosis of myofibroblasts in the lamina propria and submucosa was marked, as compared with the other three groups and apoptosis of myofibroblasts was scarcely seen at 5 days. At 5 and 7 days, the apoptotic area of myofibroblasts in the bFGF group was statistically significantly smaller when compared to the scar and sham groups.

CONCLUSION

The results confirmed that bFGF injection immediately after surgery accelerated apoptosis of myofibroblasts in mucoperiosteal denudation of rats. This may reduce maxillary growth retardation due to excessive wound contraction.

Fibrin-based scaffold incorporating VEGF- and bFGF-loaded nanoparticles stimulates wound healing in diabetic mice

Diabetic skin ulcers are difficult to heal spontaneously due to the reduced levels and activity of endogenous growth factors. Recombinant human vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are known to stimulate cell proliferation and accelerate wound healing. Direct delivery of VEGF and bFGF at the wound site in a sustained and controllable way without loss of bioactivity would enhance their biological effects. The aim of this study was to develop a poly(ether)urethane-polydimethylsiloxane/fibrin-based scaffold containing poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with VEGF and bFGF (scaffold/GF-loaded NPs) and to evaluate its wound healing properties in genetically diabetic mice (db/db). The scaffold application on full-thickness dorsal skin wounds significantly accelerated wound closure at day 15 compared to scaffolds without growth factors (control scaffold) or containing unloaded PLGA nanoparticles (scaffold/unloaded NPs). However, the closure rate was similar to that observed in mice treated with scaffolds containing free VEGF and bFGF (scaffold/GFs). Both scaffolds containing growth factors induced complete re-epithelialization, with enhanced granulation tissue formation/maturity and collagen deposition compared to the other groups, as revealed by histological analysis. The ability of the scaffold/GF-loaded NPs to promote wound healing in a diabetic mouse model suggests its potential use as a dressing in patients with diabetic foot ulcers.

[Effect of basic fibroblast growth factor and parathyroid hormone-related protein on early and late chondrogenic differentiation of rabbit bone marrow mesenchymal stem cells induced by transforming growth factor beta 1]

OBJECTIVE

To explore the impact of basic fibroblast growth factor (bFGF) and parathyroid hormone-related protein (PTHrP) on early and late chondrogenic differentiation of rabbit bone marrow mesenchymal stem cells (BMSCs) induced by transforming growth factor beta 1 (TGF-beta1).

METHODS

BMSCs were isolated from 3 healthy Japanese rabbits (2-month-old, weighing 1.6-2.1 kg, male or female), and were clutured to passage 3. The cells were put into pellet culture system and were divided into 5 groups according to different induce conditions: TGF-beta1 group (group A), TGF-beta1/bFGF group (group B), TGF-beta1/21 days bFGF group (group C), TGF-beta1/PTHrP group (group D), and TGF-beta1/21 days PTHrP group (group E). At the beginning, TGF-beta1 (10 ng/mL) was added to all groups, then bFGF and PTHrP (10 ng/mL) were added to groups B and D respectively; bFGF and PTHrP (10 ng/mL) were added to groups C and E at 21 days respectively. The gene expressions of collagen type I (Col I), Col II, Col X, matrix metalloproteinases (MMP)-13, and alkaline phosphatase (ALP) activity were detected once every week for 6 weeks. The 1, 9-dimethylmethylene blue (DMMB) staining was used to observe the extracellular matrix secretion at 6 weeks.

RESULTS

The expression of Col I in groups C and E showed a significant downward trend after 3 weeks; the expression in group A was significantly higher than that in groups C and E at 4 and 5 weeks (P < 0.05), and than that in groups B and D at 3-6 weeks (P < 0.05); and significant differences were found between groups B and C at 3 and 4 weeks, and between groups D and E at 3 weeks (P < 0.05). After 3 weeks, the expressions of Col II and Col X in groups C and E gradually decreased, and were significantly lower than those in group A at 4-6 weeks (P < 0.05). Groups B and D showed no significant difference in the expressions of Col II and Col X at all time points, but there was significant difference when compared with group A (P < 0.05). MMP-13 had no obvious expression at all time points in group A; significant differences were found between group B and groups A, C at 3 weeks (P < 0.05); and the expression was significantly higher in group D than in groups A and E (P < 0.05). ALP activity gradually increased with time in group A; after 4 weeks, ALP activity in groups C and E obviously decreased, and was significantly lower than that in group A (P < 0.05); there were significant differences between groups B and C, and between groups D and E at 2 and 3 weeks (P < 0.05). DMMB staining showed more cartilage lacuna in group A than in the other groups at 6 weeks.

CONCLUSION

bFGF and PTHrP can inhibit early and late chondrogenic differentiation of BMSCs by changing synthesis and decomposition of the cartilage extracellular matrix. The inhibition is not only by suppressing Col X expression, but also possibly by suppressing other chondrogenic protein.

[Effect of sustained-release basic fibroblast growth factor on healing of bile duct defect in pigs]

OBJECTIVE

To investigate the effects of sustained-release basic fibroblast growth factor (bFGF) on healing of bile duct defect.

METHODS

A model of bile duct wall defect (2 cm in length and 1/3-2/3 of the bile duct circumference in width) was made in 24 pigs (male or female, weighing 15-30 kg), and then defect was repaired with sustained-release bFGF collagen membrane (2.0 cm x 1.0 cm x 0.5 cm in size) in the experimental group (n=12) or with collagen membrane (2.0 cm x 1.0 cm x 0.5 cm in size) alone in the blank control group (n=12). Another 4 healthy pigs were used to obtain normal bile duct as normal control group. The survival condition of pigs was observed after operation; at 1, 2, and 3 months after operation, the blood sampling was collected to test the changes of liver function, and the bile duct specimens were harvested to count the microvessel density (MVD) and submucosal gland by HE staining and immunohistochemistry staining; and at 3 months after operation, cholangiography examination was done.

RESULTS

All the animals survived to completion of the experiment. Intra-abdominal adhesion was serious in the experimental and blank control groups at 1 week after operation, but the adhesion was markedly improved in the experimental group when compared with the blank control group with time passing. The liver function test showed that alkaline phosphatase in the experimental group was significantly lower than that in the blank control group at 2 and 3 months (P < 0.05), but no significant difference in aspartate aminortransferase, total bilirubin, and albumin was found among 3 groups (P > 0.05). The histology and immunohistochemistry staining observations showed that the regeneration rates of submucosal glands and epithelium in the experimental group were faster than those in the blank control group; defect was covered with the epithelium at 2 months, and the structure was similar to that of normal control group at 3 months; and the edema and inflammation infiltration were reduced when compared with the blank control group. The counts of MVD and submucosal gland were significantly higher than those in blank control group and normal control group at 1 month after operation (P < 0.05), and then decreased and remained at normal levels at 2 months after operation. There was a positive correlation between submucosal gland counting and MVD counting in 3 groups after operation (P < 0.01). The cholangiography examination showed no biliary dilatation or cholelithiasis after 3 months in experimental group and blank control group.

CONCLUSION

Sustained-release bFGF can promote healing of bile duct defect by accelerating the vascularization, gland regeneration, and epithelialization.

A suppository for treating cervical erosion and its preparation method

OBJECTIVE

To study a suppository for treating cervical erosion, its preparation method, and to observe its therapeutic effect on cervical erosion in animal models.

METHODS

Twenty rats were divided into five groups: blank control group, model group, and three different therapeutic concentration groups. Phenol slurry was injected through the vagina to create cervical erosion animal models. After seven days of drug treatment, the difference of cervical histopathology was observed and compared between different groups.

RESULTS

Compared with the control group, the model group showed obvious cervical erosion, inflammatory cell infiltration, vascular dilatation, and congestion. Among the administration group, the high administration group had the least inflammation and cell infiltration in the mucous membrane.

CONCLUSIONS

There is a significant effect of therapeutic drugs in rats with cervical erosion, which is related to the concentration of drugs.

Heparinized magnetic mesoporous silica nanoparticles as multifunctional growth factor delivery carriers

Well-defined magnetic mesoporous silica nanoparticles (MMSNs) with a core/shell structure were prepared via a one pot synthesis. Sphere-like magnetite aggregates were obtained as cores of the final nanoparticles by assembly in the presence of polyvinyl pyrrolidone and cetyltrimethylammonium bromide. The nanoparticles have the property of superparamagnetism with a saturation magnetization value of 20.3 emu g(-1). In addition, the combination of heparin and fluorescence-labeled MMSNs endows the resultant particles (denoted as MFMSNs-HP) with magnetism and fluorescence properties, excellent dispersity in the buffer solutions and cell culture media, anticoagulant activity in the blood stream, and the controlled release of basic fibroblast growth factor (bFGF). Furthermore, the bFGF cell viability assays indicate that MFMSNs-HP has nearly no toxicity to human umbilical vein endothelial cells (HUVEC) up to a concentration of 200 μg ml(-1), and the proliferation activity of bFGF incorporated into MFMSNs-HP could be retained for at least 6 days. All of these suggest that MFMSNs-HP may serve as a multifunctional carrier for the delivery of growth factors.

Small molecule-assisted, line-independent maintenance of human pluripotent stem cells in defined conditions

Human pluripotent stem cells (hPSCs) are conventionally grown in a mouse feeder cell-dependent manner. Chemically defined culture conditions are, however, desirable not only for potential medically oriented applications but also for investigating mechanisms of self-renewal and differentiation. In light of the rather high complexity and cost of existing defined hPSC culture systems, we have systematically evaluated over 20 potential media ingredients. Only components that reproducibly gave beneficial effects were ultimately combined to yield a simple and cost-effective formulation termed FTDA. This xeno-free medium is based on mimicking self-renewal factor activities present in mouse embryonic fibroblast-conditioned medium, at minimal dosages. Additionally, small molecule inhibitors of BMP and WNT signaling served to specifically suppress typical types of spontaneous differentiation seen in hPSC cultures. FTDA medium was suitable for the generation of human induced pluripotent stem cells and enabled robust long-term maintenance of diverse hPSC lines including hard-to-grow ones. Comparisons with existing defined media suggested reduced spontaneous differentiation rates in FTDA. Our results imply that using supportive factors at minimal concentrations may still promote robust self-renewal and preserve pluripotency of hPSCs.

Cell-engineered human elastic chondrocytes regenerate natural scaffold in vitro and neocartilage with neoperichondrium in the human body post-transplantation

We have developed a unique method that allows us to culture large volumes of chondrocyte expansion from a small piece of human elastic cartilage. The characteristic features of our culturing method are that fibroblast growth factor-2 (FGF2), which promotes proliferation of elastic chondrocytes, is added to a culture medium, and that cell-engineering techniques are adopted in the multilayered culture system that we have developed. We have subsequently discovered that once multilayered chondrocytes are transplanted into a human body, differentiation induction that makes use of surrounding tissue occurs in situ, and a large cartilage block is obtained through cartinogenesis and matrix formation. We have named this method two-stage transplantation. We have clinically applied this transplantation method to the congenital ear defect, microtia, and reported successful ear reconstruction. In our present study, we demonstrated that when FGF2 was added to elastic chondrocytes, the cell count increased and the level of hyaluronic acid, which is a major extracellular matrix (ECM) component, increased. We also demonstrated that these biochemical changes are reflected in the morphology, with the elastic chondrocytes themselves producing a matrix and fibers in vitro to form a natural scaffold. We then demonstrated that inside the natural scaffold thus formed, the cells overlap, connect intercellularly to each other, and reconstruct a cartilage-like three-dimensional structure in vitro. We further demonstrated by immunohistochemical analysis and electron microscopic analysis that when the multilayered chondrocytes are subsequently transplanted into a living body (abdominal subcutaneous region) in the two-stage transplantation process, neocartilage and neoperichondrium of elastic cartilage origin are regenerated 6 months after transplantation. Further, evaluation by dynamic mechanical analysis showed the regenerated neocartilage to have the same viscoelasticity as normal auricular cartilage. Using our multilayered culture system supplemented with FGF2, elastic chondrocytes produce an ECM and also exhibit an intercellular network; therefore, they are able to maintain tissue integrity post-transplantation. These findings realized a clinical application for generative cartilage surgery.

Effects of bFGF incorporated into a gelatin sheet on wound healing

Basic fibroblast growth factor (bFGF) is well known to promote the proliferation of almost all cells associated with wound healing. However, as the activation duration of bFGF is very short in vivo, we incorporated bFGF into an acidic gelatin hydrogel and studied the sustained release of bFGF in vivo. In addition, we investigated the effects of the acidic gelatin sheet containing bFGF on wound healing. To distinguish wound contraction from neoepithelialization, we measured both the wound area and neoepithelium length. Other histological parameters such as thickness of granulation tissue and number of capillaries were also determined as indices of wound healing. Fibrous tissue was assessed using an Elastica van Gieson and Azan stain. A skin defect (1.5 x 1.5 cm) of full thickness was created on the back of each test mouse and the wound was covered with an acidic gelatin hydrogel, referred to as a gelatin sheet in this study (2 x 2 cm), with bFGF (100 microg/site) (A) or without bFGF (B). 1, 2, 3, 5, 7 and 14 days after covering, mice were killed and an enzyme-linked immunosorbent assay (ELISA) was performed to estimate the concentration of bFGF in the plasma. In another experiment, each wound was covered with (A), (B) or a hydrogel dressing (control group, C) and the wound area was measured 1 or 2 weeks postoperatively with a computer planimeter. The histological parameters, as mentioned above, were assessed using a light microscope. Sustained release of bFGF from the gelatin sheet was observed and the gelatin sheet containing bFGF promoted neoepithelialization, granulation, neovascularization and wound closure. This gelatin sheet containing bFGF was concluded to be effective for wound healing and promising for clinical use.

GDF-9 and bFGF enhance the effect of FSH on the survival, activation, and growth of cattle primordial follicles

This study aims to investigate the effects of follicle stimulating hormone (FSH) in combination with growth and differentiation factor-9 (GDF-9) or basic fibroblast growth factor (bFGF) on the activation, survival and growth of cattle primordial follicles. Ovarian tissues were cultured for 3, 7, 14, 22 days in α minimum essential medium (α-MEM) supplemented with FSH, FSH+GDF-9 or FSH+bFGF. Non-cultured and cultured ovarian fragments were processed for histological and TUNEL analysis. Compared to the FSH medium, the results showed FSH+GDF-9 medium increased the percentage of primary follicles in all culture periods and secondary follicles after 14 days of culture (P<0.05), meanwhile the diameter of primary and secondary follicles were also observed to increase in this medium after 7 days of cultures (P<0.05). FSH+bFGF medium appeared to increase the percentage of primary follicles after 14 days of culture and secondary follicles at day 14 of culture than FSH medium (P<0.05). Furthermore, the FSH+GDF-9 and FSH+bFGF mediums had a greater percentage of normal follicles, and lesser apoptotic cell rates than FSH medium. The results first indicated that FSH in combination with GDF-9 or bFGF can improve the survival, activation, and growth of cattle primordial follicles after the long-term culture of ovarian cortex.

MRI study of cryoinjury infarction in pig hearts: i. Effects of intrapericardial delivery of bFGF/VEGF embedded in alginate beads

The aim of the study was the testing of sustained intrapericardial delivery of vascular growth factors (GFs) from alginate beads on cryoinjury size and perfusion. In domestic pigs (15-20 kg, n = 21), the left ventricular (LV) anterolateral wall of exposed hearts was cryoinjured using an aluminum rod (25 mm o.d.) cooled in liquid nitrogen. Alginate beads (d = 3.2 ± 0.2 mm), containing human recombinant basic fibroblast GF (bFGF, 50 µg) and vascular endothelial GF (VEGF, 50 µg) + heparin (50 µg) or heparin alone (Con, n = 5), were sutured to the cryoinjured epicardium (GF, n = 5; Con, n = 3 ) or pericardium (GF, n = 3; Con, n = 2), or no beads were implanted (n = 4). Four pigs were sham-operated. Cine and T(1) -weighted MRI was performed in vivo at ~2.5 h and 1, 2, 3 and 4 weeks after injury in a 3T imager. A double bolus of GdDTPA was injected (0.05 and 0.15 mmol/kg) and first-pass and late enhancement kinetics were monitored. After 4-week cryoinjury, following the injection of 5 x 10(6) 15-µm NIR fluorescent microspheres (FMS, 645/680 nm), hearts were sliced and examined with fluorescence imaging. Triphenyltetrazolium chloride (TTC) staining was used to determine infarct areas. Epicardial GF-containing beads were encapsulated within the hypointense 3-4-week infarct tissue. This tissue had a 75% higher LV thickening index, a lower distribution volume for GdDTPA (0.44 ± 0.12 vs 0.68 ± 0.05, p = 0.02), and 25% faster first-pass Gd kinetics relative to control infarctions. TTC staining revealed TTC-positive islands in the core of treated infarcts, which showed higher FMS fluorescence relative to surrounding infarct tissue (0.64 ± 0.14 vs. 0.31 ± 0.14; p < 0.0001) and to control infarcts (0.37 ± 0.09, p < 0.05). GF-beads attached to the pericardium were not effective. We conclude that sustained intrapericardial release of bFGF + VEGF from alginate beads attached to the epicardium facilitated vascular growth in the cryoinjured area.

[Present status of periodontal regeneration - FGF-2 and Teriparatide - ]

Periodontal regenerative therapy is required to regain the tooth function and oral health for patients with periodontal diseases. We reported that topical application of basic fibroblast growth factor (FGF-2) into alveolar bone defects stimulated significant periodontal regeneration in periodontitis patients. On the other hand, subcutaneous administration of Teriparatide, a drug composed of the first 34 amino acids of parathyroid hormone that has anabolic effects for osteoporosis, has been reported to induce periodontal regeneration in the clinical trial. Both of the therapies have been expected to be the periodontal regeneration therapy of the next generation. In this review, we introduce the present status of these new periodontal regenerative therapies.

Enhancement of nose-to-brain delivery of basic fibroblast growth factor for improving rat memory impairments induced by co-injection of β-amyloid and ibotenic acid into the bilateral hippocampus

Basic fibroblast growth factor (bFGF) delivery to the brain of animals appears to be an emerging potential therapeutic approach to neurodegenerative diseases, such as Alzheimer's disease (AD). The intranasal route of administration could provide an alternative to intracerebroventricular infusion. A nasal spray of bFGF had been developed previously and the objective of the present study was to investigate whether bFGF nasal spray could enhance brain uptake of bFGF and ameliorate memory impairment induced by co-injection of β-amyloid(25-35) and ibotenic acid into bilateral hippocampus of rats. The results of brain uptake study showed that the AUC(0-12h) of bFGF nasal spray in olfactory bulb, cerebrum, cerebellum and hippocampus was respectively 2.47, 2.38, 2.56 and 2.19 times that of intravenous bFGF solution, and 1.11, 1.95, 1.40 and 1.93 times that of intranasal bFGF solution, indicating that intranasal administration of bFGF nasal spray was an effective means of delivering bFGF to the brain, especially to cerebrum and hippocampus. In Morris water maze tasks, intravenous administration of bFGF solution at high dose (40 μg/kg) showed little improvement on spatial memory impairment. In contrast, bFGF solution of the same dose following intranasal administration could significantly ameliorate spatial memory impairment. bFGF nasal spray obviously improved spatial memory impairment even at a dose half (20 μg/kg) of bFGF solution, recovered their acetylcholinesterase and choline acetyltransferase activity to the sham control level, and alleviated neuronal degeneration in rat hippocampus, indicating neuroprotective effects on the central nerve system. In a word, bFGF nasal spray may be a new formulation of great potential for treating AD.

A novel vaccine delivery system: biodegradable nanoparticles in thermosensitive hydrogel

In this work, a novel vaccine delivery system, biodegradable nanoparticles (NPs) in thermosensitive hydrogel, was investigated. Human basic fibroblast growth factor (bFGF)-loaded NPs (bFGF-NPs) were prepared, and then bFGF-NPs were incorporated into thermosensitive hydrogel to form bFGF-NPs in a hydrogel composite (bFGF-NPs/hydrogel). bFGF-NPs/hydrogel was an injectable sol at ambient temperature, but was converted into a non-flowing gel at body temperature. The in vitro release profile showed that bFGF could be released from bFGF-NPs or bFGF-NPs/hydrogel at an extended period, but the release rate of bFGF-NPs/hydrogel was much lower. In vivo experiments suggested that immunogenicity of bFGF improved significantly after being incorporated into the NPs/hydrogel composite, and strong humoral immunity was maintained for longer than 12 weeks. Furthermore, an in vivo protective anti-tumor immunity assay indicated that immunization with bFGF-NPs/hydrogel could induce significant suppression of the growth and metastases of tumors. Thus, the NPs/hydrogel composite may have great potential application as a novel vaccine delivery system.

Molecular mechanisms of basic fibroblast growth factor effect on healing of ulcerative colitis in rats

We demonstrated previously that basic fibroblast growth factor (bFGF) accelerated the healing of experimental duodenal ulcers, and we now hypothesize that bFGF might also accelerate the healing of experimental ulcerative colitis (UC). We also explored the potential molecular mechanisms involved in the accelerated healing of UC in rats treated with bFGF. The results demonstrated that colonic lesions were significantly reduced by bFGF treatment, whereas neutralization of bFGF aggravated iodoacetamide-induced UC. Protein expression of bFGF was increased during the healing stage of UC. Tumor necrosis factor-α levels and myeloperoxidase activity were significantly decreased in UC rats treated with bFGF, whereas they increased in rats treated with anti-bFGF antibody. Real-time polymerase chain reaction and immunohistochemistry showed decreased levels of p27 in the UC rats compared with the healthy controls, which was reversed by bFGF treatment in a dose-dependent manner. By immunohistochemistry and double labeling of Ki-67 and CD34, prominent positive staining of Ki-67 and CD34 was seen after bFGF treatment, indicating the enhanced proliferation of fibroblasts and epithelial and endothelial cells, i.e., angiogenesis. We conclude that bFGF plays a beneficial role in the healing of UC in rats. The molecular mechanisms of bFGF in UC healing not only involve the expected increased cell proliferation, especially angiogenesis, but also encompass the reduction of inflammatory cytokines and infiltration of inflammatory cells. Thus, bFGF enema may be a new therapeutic option for UC.

[An experimental study on the basic fibroblast growth factor slow-releasing microsphere for knee osteoarthritis in the rabbit]

OBJECTIVE

To study the therapeutic effect of chitosan-coated basic fibroblast growth factor (bFGF) slow-releasing microspheres on the knee osteoarthritis in the rabbit.

METHODS

From November 2008 to July 2009, 54 New Zealand rabbits were divided into 6 groups at random, which were the control group, the model group, the PBS-M group, the bFGF-S group, the 10-bFGF-M group and the 100-bFGF-M group, respectively. The model of knee osteoarthritis was induced by the injection of papain in the rabbit. Except the control and model groups, all the experimental groups were implanted 1 ml intervention solution at the third and sixth weeks, including the PBS microspheres, bFGF solution, 10 µg bFGF microspheres and 100 µg bFGF microspheres, respectively. The rabbits were sacrificed at the ninth week after operation, and then articular cartilage was conducted the morphological and histopathological evaluation.

RESULTS

The damage of articular cartilage in the model group was more serious than that in the control group, with statistical differences according to the Ink score (t = 8.22, P = 0.00) and Mankin score (t = 17.20, P = 0.00). The damage of articular cartilage in the PBS-M and bFGF-S groups were similar with that in the model group, according to the Ink score (t = 0.26, P = 0.79; t = 0.80, P = 0.45) and Mankin score (t = 1.51, P = 0.17; t = 0.56, P = 0.60). The Ink and Mankin scores in the 10-bFGF-M and 100-bFGF-M groups were better than that in the model group (Ink score: t = 3.58, P = 0.01; t = 6.82, P = 0.00; Mankin score: t = 3.41, P = 0.01; t = 5.00, P = 0.00), with the 100-bFGF-M group much better (t = 5.29, P = 0.00; t = 2.80, P = 0.02).

CONCLUSIONS

The bFGF slow-releasing microsphere can keep its effective intra-articular concentration, which may accelerate the synthesis of proteoglycan and inhibit its decomposition to reverse the damage of articular cartilage.

Polybrene inhibits human mesenchymal stem cell proliferation during lentiviral transduction

Human mesenchymal stem cells (hMSCs) can be engineered to express specific genes, either for their use in cell-based therapies or to track them in vivo over long periods of time. To obtain long-term expression of these genes, a lentivirus- or retrovirus-mediated cell transduction is often used. However, given that the efficiency with these viruses is typically low in primary cells, additives such as polybrene are always used for efficient viral transduction. Unfortunately, as presented here, exposure to polybrene alone at commonly used concentratons (1–8 µg/mL) negatively impacts hMSC proliferation in a dose-dependent manner as measured by CyQUANT, EdU incorporation, and cell cycle analysis. This inhibition of proliferation was observable in culture even 3 weeks after exposure. Culturing the cells in the presence of FGF-2, a potent mitogen, did not abrogate this negative effect of polybrene. In fact, the normally sharp increase in hMSC proliferation that occurs during the first days of exposure to FGF-2 was absent at 4 µg/mL or higher concentrations of polybrene. Similarly, the effect of stimulating cell proliferation under simulated hypoxic conditions was also decreased when cells were exposed to polybrene, though overall proliferation rates were higher. The negative influence of polybrene was, however, reduced when the cells were exposed to polybrene for a shorter period of time (6 hr vs 24 hr). Thus, careful evaluation should be done when using polybrene to aid in lentiviral transduction of human MSCs or other primary cells, especially when cell number is critical.

[Effect of local basic fibroblast growth factor and 5-fluorouracil on accelerating healing and preventing tendon adhesion after flexor tendon repair]

OBJECTIVE

To assess the effect of basic fibroblast growth factor (bFGF) and 5-fluorouracil (5-FU) applied topically on the tendon adhesion and the healing process after the flexor tendon repair in Leghorn chickens.

METHODS

Ninety male Leghorn chickens (weighing 3.0-3.5 kg) were randomly divided into 3 groups, with 30 chickens in each group. The flexor digitorum profundus tendons of the third right toes were transected and sutured directly. The repair site in group A was given 0.6 microL fibrin sealant (FS). In group B, the repair site was given 0.6 microL FS containing 500 ng bFGF. In group C, before the tendons were transected, they had been soaked in 5-FU solution, and then the same treatment as group B was given. Six specimens of the third toe were harvested to perform the macroscopical and histological examinations at 1, 2, 4, and 8 weeks, respectively, and to perform the biomechanical test at 8 weeks.

RESULTS

All animals survived until the experiment was completed. All incisions healed smoothly. No rupture occurred in the repaired tendon. At 8 weeks, the adhesion degree was lighter in group C than in group B (P < 0.05), but there was no significant difference in the adhesion degree between group A and groups B, C (P > 0.05). At 1, 2, and 4 weeks after operation, the number of fibroblast cells of group A was significantly less than that of group B (P < 0.05), and the number of fibroblast cells of group C was significantly less than that of group A and group B in the tendon sheath and epitenon (P < 0.05); however, it was significantly more than that of group A in the tendon parenchyma (P < 0.05), and no significant difference was observed when compared with that of group B (P > 0.05). At 8 weeks, no difference was found among 3 groups (P > 0.05). The collagen fiber content of group A was significantly less than that of group B at 4 and 8 weeks (P < 0.05). In the sheath and epitenon, the collagen fiber content of group A was significantly more than that of group C at 4 weeks (P < 0.05); however, no significant difference was found between 2 groups at 8 weeks (P > 0.05). The collagen fiber content of group A was significantly less than that of group C in the parenchyma at 4 and 8 weeks (P < 0.05). At all time points, the collagen fiber content of group B was significantly more than that of group C in the sheath and epitenon (P < 0.05), but no significant difference in the parenchyma was observed between 2 groups (P > 0.05). The biomechanical tests showed that the gliding excursion of the tendon in groups A, B, and C was (3.51 +/- 0.56), (2.84 +/- 0.42), and (4.56 +/- 0.59) mm, respectively; the work of flexion was (14.08 +/- 1.85), (20.62 +/- 3.52), and (10.91 +/- 1.53) N x mm, respectively; and the ultimate tensile strength of the tendon was (11.26 +/- 1.83), (15.02 +/-2.20), and (14.40 +/- 1.57) N, respectively. There were significant differences in the gliding excursion of the tendon and the work of flexion among 3 groups (P < 0.05) and in the ultimate tensile strength of the tendon between group A and groups B, C (P < 0.05), but there was no significant difference in the ultimate tensile strength of the tendon between group B and group C (P > 0.05).

CONCLUSION

Local single-use bFGF and 5-FU can not only effectively promote the healing of flexor tendon, but also significantly reduce tendon adhesion.

[Effects of ferulic acid on bFGF-treated PC12 cells]

OBJECTIVE

To explore the effect and mechanism of ferulic acid on differentiation in bFGF-treated PC12 cells.

METHODS

The length of neurite outgrowth and the percentage of PC12 cells induced in the presence of 0 ng/mL or 1 ng/mL bFGF were assayed.

RESULTS

Compared with that of control group,ferulic acid could enhance the differentiation effect of bFGF (1 ng/mL) in PC12 cells (P < 0.01) and the enhancing effect could be blocked by the specific MAPK kinase inhibitor, PD98059.

CONCLUSION

Ferulic acid potentiates neurite outgrowth in bFGF-treated PC12 cells by MAPK-dependent signaling pathway.