Regeneration of periodontal tissues by basic fibroblast growth factor

Periodontal tissue regeneration with cementogenesis after application of brain-derived neurotrophic factor in 3-wall inflamed intra-bony defect

OBJECTIVE

The purpose of this study is to investigate regenerative process by immunohistochemical analysis and evaluate periodontal tissue regeneration following a topical application of BDNF to inflamed 3-wall intra-bony defects.

BACKGROUND

Brain-derived neurotrophic factor (BDNF) plays a role in the survival and differentiation of central and peripheral neurons. BDNF can regulate the functions of non-neural cells, osteoblasts, periodontal ligament cells, endothelial cells, as well as neural cells. Our previous study showed that a topical application of BDNF enhances periodontal tissue regeneration in experimental periodontal defects of dog and that BDNF stimulates the expression of bone (cementum)-related proteins and proliferation of human periodontal ligament cells.

METHODS

Six weeks after extraction of mandibular first and third premolars, 3-wall intra-bony defects were created in mandibular second and fourth premolars of beagle dogs. Impression material was placed in all of the artificial defects to induce inflammation. Two weeks after the first operation, BDNF (25 and 50 μg/mL) immersed into atelocollagen sponge was applied to the defects. As a control, only atelocollagen sponge immersed in saline was applied. Two and four weeks after the BDNF application, morphometric analysis was performed. Localizations of osteopontin (OPN) and proliferating cell nuclear antigen (PCNA)-positive cells were evaluated by immunohistochemical analysis.

RESULTS

Two weeks after application of BDNF, periodontal tissue was partially regenerated. Immunohistochemical analyses revealed that cells on the denuded root surface were positive with OPN and PCNA. PCNA-positive cells were also detected in the soft connective tissue of regenerating periodontal tissue. Four weeks after application of BDNF, the periodontal defects were regenerated with cementum, periodontal ligament, and alveolar bone. Along the root surface, abundant OPN-positive cells were observed. Morphometric analyses revealed that percentage of new cementum length and percentage of new bone area of experimental groups were higher than control group and dose-dependently increased.

CONCLUSION

These findings suggest that BDNF could induce cementum regeneration in early regenerative phase by stimulating proliferation of periodontal ligament cells and differentiation into periodontal tissue cells, resulting in enhancement of periodontal tissue regeneration in inflamed 3-wall intra-bony defects.

A supramolecular hydrogel dressing with antibacterial, immunoregulation, and pro-regeneration ability for biofilm-associated wound healing

Chronic wound treatment has emerged as a significant healthcare concern worldwide due to its substantial economic burden and the limited effectiveness of current treatments. Effective management of biofilm infections, regulation of excessive oxidative stress, and promotion of tissue regeneration are crucial for addressing chronic wounds. Hydrogel stands out as a promising candidate for chronic wound treatment. However, its clinical application is hindered by the difficulty in designing and fabricating easily and conveniently. To overcome these obstacles, we present a supermolecular G-quadruplex hydrogel with the desired multifunction via a dynamic covalent strategy and Hoogsteen-type hydrogen bonding. The G-quadruplex hydrogel is made from the self-assembly of guanosine, 2-formylphenyboronic acid, polyethylenimine, and potassium chloride, employing dynamic covalent strategy and Hoogsteen-type hydrogen bonding. In the acidic/oxidative microenvironment associated with bacterial infections, the hydrogel undergoes controlled degradation, releasing the polyethylenimine domain, which effectively eliminates bacteria. Furthermore, nanocomplexes comprising guanosine monophosphate and manganese sulfate are incorporated into the hydrogel skeleton, endowing it with the ability to scavenge reactive oxygen species and modulate macrophages. Additionally, the integration of basic fibroblast growth factor into the G-quadruplex skeleton through dynamic covalent bonds facilitates controlled tissue regeneration. In summary, the facile preparation process and the incorporation of multiple functionalities render the G-quadruplex hydrogel a highly promising candidate for advanced wound dressing. It holds great potential to transition from laboratory research to clinical practice, addressing the pressing needs of chronic wound management.

Predictive factors of periodontal regeneration outcomes using rhFGF-2: A case-control study

OBJECTIVE

This study aimed to investigate the factors influencing the clinical outcomes of regenerative therapy using recombinant human fibroblast growth factor-2 (rhFGF-2).

BACKGROUND

rhFGF-2 promotes periodontal regeneration, and identifying the factors influencing this regeneration is important for optimizing the effectiveness of rhFGF-2.

METHODS AND MATERIALS

This study used a hospital information-integrated database to identify patients who underwent periodontal regenerative therapy with rhFGF-2. Factors included age, smoking status, diabetes mellitus (DM), periodontal inflamed surface area (PISA) at the initial visit, whether the most posterior tooth was involved or not, and preoperative radiological bone defect angle. Periodontal regenerative therapy outcomes were defined as good if radiographic bone fill ≥35% or periodontal pocket closure at 9-15 months after surgery. Bone fill rate (%) and periodontal pocket depth (mm) were also used as outcome measures. Factors were evaluated by simple regression analysis, and then the association between factors and the outcomes was determined by multivariate analysis.

RESULTS

PISA and age at the first visit did not significantly influence the success or failure of bone fill rate byrhFGF-2. However, DM, radiographic bone defect angle, and the most posterior tooth significantly influenced the regenerative effect (success/failure in bone fill) of rhFGF-2. The most posterior tooth was significantly associated with bone fill rate by rhFGF-2. Examination of the association between pocket closure and factors shows that the most posterior tooth significantly influenced. The most posterior tooth and preoperative PPD were significantly associated with pocket reduction depth. For the most posterior tooth, a significantly higher bone regeneration rate (p < .05) was observed with a combination of autologous bone graft and rhFGF-2 than with rhFGF-2 alone, and the effect was significant in multivariate analysis.

CONCLUSIONS

The radiographic bone defect angle, the involvement of most posterior teeth, and the presence of DM influenced the effectiveness of rhFGF-2 in periodontal regeneration. However, PISA values and age at the initial visit had no significant effect.

Synergistic effect of FGF-2 and TGF-β1 on the mineralization of human umbilical cord perivascular cells

OBJECTIVE

Human umbilical cord perivascular cells (HUCPVCs) are derived from the human umbilical cord perivascular tissue and are expected to replace mesenchymal stromal cells in the future. We investigated the synergistic effects of fibroblast growth factor 2 (FGF-2) and transforming growth factor-beta 1 (TGF-β1) on HUCPVC mineralization.

DESIGN

We prepared HUCPVCs with (FGF(+)HUCPVCs) or without FGF-2 (FGF(-)HUCPVCs) in the presence of activated vitamin D3, a bone morphogenic protein inhibitor, and TGF-β1. We examined the cell proliferative capacity, expression of various hard tissue-forming cell gene markers, and mineralization induction ability and identified the crystalline phases of the mineralized nodules.

RESULTS

FGF(+)HUCPVCs exhibited higher intracellular alkaline phosphatase (ALP) gene expression and ALP activity, and their cell proliferation rate was higher than that of FGF(-)HUCPVCs. The expression levels of osteoblast marker genes increased in FGF(+)HUCPVCs, whereas those of elastic fiber and muscle cell markers increased in FGF(-)HUCPVCs. The expression of genes related to matrix vesicle-mediated mineralization was increased in FGF(+)HUCPVCs. While FGF(-)HUCPVCs displayed myofibroblast-like properties and could not induce mineralization, FGF(+)HUCPVCs demonstrated the ability to produce mineralized nodules. The resulting mineralized nodules consisted of hydroxyapatite as the major phase and minor amounts of octacalcium phosphate. The mineralized nodules exhibited the morphological characteristics of bone hydroxyapatite, composed of fibrous hydroxyapatite nanorods and polycrystalline sheets.

CONCLUSION

We found that FGF-2 synergizes with TGF-β1 and is a key factor in the differentiation of HUCPVCs into osteoblast-like cells. Thus, HUCPVCs can potentially serve as a new stem cell source for future bone regeneration and dental treatments.

Effects of combined application of fibroblast growth factor (FGF)-2 and carbonate apatite for tissue regeneration in a beagle dog model of one-wall periodontal defect

Introduction

There has been an increasing desire for the development of predictive periodontal regenerative therapy for severe periodontitis. In this study, we investigated the effect of the combined use of fibroblast growth factor-2 (FGF-2), a drug for periodontal regeneration approved in Japan, and carbonated apatite (CO₃Ap), bioresorbable and osteoconductive scaffold, on periodontal regeneration in beagle dog model of one-wall periodontal defect (severe intraosseous defect) for 24 weeks in comparison with CO₃Ap or vehicle alone.

Methods

One-wall periodontal defects were created (mesiodistal width × depth: 4 × 4 mm) on the mesial portion of the mandibular first molar (M1) of beagle dogs on both side. Mixture of FGF-2 and CO₃Ap, vehicle and CO₃Ap, or vehicle alone were administered to the defects and designated as groups FGF-2+CO₃Ap, CO₃Ap, and control, respectively. To assess the periodontal regeneration, radiographic analysis over time for 24 weeks, and micro computed tomography (μCT) and histological evaluation at 6 and 24 weeks were performed.

Results

For the regenerated tissue in the defect site, the mineral content of the FGF-2+CO₃Ap group was higher than that of the CO₃Ap group in the radiographic analysis at 6-24 weeks. In the context of new bone formation and replacement, the FGF-2+CO₃Ap group exhibited significantly greater new bone volume and smaller CO₃Ap volume than the CO₃Ap group in the μCT analysis at 6 and 24 weeks. Furthermore, the density of the new bone in the FGF-2+CO₃Ap group at 24 weeks was similar to those in the control and CO₃Ap groups. Histological evaluation revealed that the length of the new periodontal ligament and cementum in the FGF-2+CO₃Ap group was greater than that in the CO₃Ap group at 6 weeks. We also examined the effect of the combined use of the FGF-2 and CO₃Ap on the existing bone adjacent to the defect and demonstrated that the existing bone height and volume in the FGF-2+CO₃Ap group remained significantly greater than those in the CO₃Ap group.

Conclusion

This study demonstrated that the combination of FGF-2 and CO₃Ap was effective not only in enhancing new bone formation and replacing scaffold but also in maintaining the existing bone adjacent to the defect site in a beagle dog model of one-wall periodontal defect. Additionally, new periodontal tissues induced by FGF-2 and CO₃Ap may follow a maturation process similar to that formed by spontaneous healing. This suggests that the combined use of FGF-2 and CO₃Ap would promote periodontal regeneration in severe bony defects of periodontitis patient.

Regenerative Potential of Bone Morphogenetic Protein 7-Engineered Mesenchymal Stem Cells in Ligature-Induced Periodontitis

Periodontitis is an oral disease caused by bacterial infection that has stages according to the severity of tissue destruction. The advanced stage of periodontitis presents irreversible destruction of soft and hard tissues, which finally results in loss of teeth. When conventional treatment modalities show limited results, tissue regeneration therapy is required in patients with advanced periodontitis. In the present study, we aimed to evaluate the effect of bone marrow-derived mesenchymal stem cells (BM-MSCs) delivering bone morphogenetic protein 7 (BMP7) on tissue regeneration in a periodontitis model. BMP7 is a member of the BMP family that shows bone-forming ability; however, BMPs rapid clearing and degradation and unproven efficacy make it difficult to apply it in clinical dentistry. To overcome this, we established BMP7-expressing engineered BM-MSCs (BMP7-eBMSCs) that showed superior osteogenic differentiation potential when subcutaneously transplanted with a biphasic calcium phosphate scaffold into immunocompromised mice. Furthermore, the efficacy of BMP7-eBMSC transplantation for periodontal tissue regeneration was evaluated in a rat ligature-induced periodontitis model. Upon measuring two-dimensional and three-dimensional amounts of regenerated alveolar bone using microcomputed tomography, the amounts were found to be significantly higher in the BMP7-eBMSC transplantation group than in the eBMSC transplantation group. Most importantly, fibrous periodontal ligament (PDL) tissue regeneration was also achieved upon BMP7-eBMSC transplantation, which was evaluated by calculating the modified relative connective tissue attachment. The amount of connective tissue attachment in the BMP7-eBMSC transplantation group was significantly higher than that in the ligature-induced periodontitis group, although the increase was comparable between the BMP7-eBMSC and human PDL stem cell transplantation groups. Taken together, our results suggested that sustainable release of BMP7 induces periodontal tissue regeneration and that transplantation of BMP7-eBMSCs is a feasible treatment option for periodontal regeneration. Impact Statement Periodontitis is the second most common human dental disease affecting chronic systemic diseases. Despite the tremendous efforts trying to cure the damaged periodontal tissues using tissue engineering technologies, a definitive regenerative method has not been in consensus. Researchers are seeking more feasible and abundant source of mesenchymal stem cells (MSCs), and furthermore, how to use reliable growth factors under more efficient control are the issues to be solved. In this study, we aimed to evaluate the effect of bone morphogenetic protein 7 (BMP7) gene delivering bone marrow-derived MSCs on periodontal tissue regeneration to evaluate the efficacy of BMP7 and engineered BMSCs for periodontal tissue regeneration.

The bFGF Can Improve Angiogenesis in Oral Mucosa and Accelerate Wound Healing

Background

The role of the basic fibroblast growth factor (bFGF) has well known in the angiogenesis and ulcer healing. In this study, we aimed to evaluate the effects of bFGF on tissue repair in a rat oral mucosal wound.

Methods

Musosal wound induced on the lip mucosa of rats and bFGF was injected along the edge of the mucosal defect immediately after surgery. The tissues were collected on days 3, 7 and 14 after the wound induction. The micro vessel density (MVD) and CD34 expression were done by histochemical studies.

Results

The bFGF significantly accelerated granulation tissue formation and MVD was increased three days after ulcer induction but decreased 14 days after surgery. The MVD was significantly higher in the bFGF-treated group. The wound area was decreased in all groups time-dependently and a statistically significant difference (p value?) was observed between the bFGF-treated group and untreated group. The wound area was smaller in the bFGF-treated group compared to the untreated group.

Conclusions

Our data demonstrated that bFGF can accelerated and facilitated wound healing.

An exploratory clinical trial to evaluate the safety and efficacy of combination therapy of REGROTH® and Cytrans® granules for severe periodontitis with intrabony defects

Introduction

Currently, flap operation (FOP) using REGROTH® (0.3% basic fibroblast growth factor [FGF-2]) is the standard treatment for periodontal regenerative therapy in Japan. However, the periodontal tissue regenerative effect with REGROTH® monotherapy is inadequate for severe alveolar bone defects. Therefore, in this study, we evaluated the safety and effectiveness of periodontal regenerative therapy for patients with severe periodontitis using REGROTH® (test medicine) combined with Cytrans® Granules (test device: carbonated apatite granules), which is a new artificial bone.

Methods

The study participants included 10 patients with severe periodontitis (mean age: 47.4 years). All participants provided written informed consents. In each patient, the intrabony defect site (mean bone defect depth: 5.7 mm) was defined as the test site. FOP was performed for the test site after the baseline investigation; moreover, the test medicine and test device were administered simultaneously. Furthermore, the observation of subjects’ general condition and test sites was conducted and the blood, urine, and periodontal tissue tests were performed up to 36 weeks after FOP. The rate of bone increase (%), clinical attachment level (CAL), probing pocket depth (PPD), bleeding on probing (BOP), tooth mobility (Mo), width of keratinized gingiva (KG), gingival recession (REC), gingival index (GI), and plaque index (PlI) were evaluated during the periodontal tissue investigation.

Results

As the primary endpoint, no adverse events related to the test medicine and test device occurred during the entire observation period of this study. Regarding the secondary endpoints, there was a significant increase in new alveolar bone (p = 0.003) and CAL acquisition (p = 0.001) as well as decrease in PPD (p = 0.002) and BOP (p = 0.016) at 36 weeks after administration of the test medicine and test device compared with the preoperative values. Furthermore, at 36 weeks after surgery, the Mo, GI, and PlI decreased to preoperative levels at 40%, 60%, and 30% of sites, respectively. However, at 36 weeks after surgery, there was no difference in KG and REC compared with their preoperative values.

Conclusions

The safety of periodontal regenerative therapy using the test medicine in combination with the abovementioned test device was confirmed. In addition, it was suggested that this periodontal regenerative therapy is effective for tissue regeneration in severe alveolar bone defects.

This clinical trial was conducted after registering and publicizing as a specified clinical trial in the Japan registry of clinical trials (jRCTs051190045).

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The safety of flap operation using 0.3% FGF-2 and carbonated apatite was confirmed.

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The administration of 0.3% FGF-2 and carbonated apatite improved periodontitis.

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Combining 0.3% FGF-2 and carbonated apatite for severe alveolar bone defects.

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Periodontal regenerative therapy combining both could be effective.

Periodontal Regenerative Therapy Using rhFGF-2 and Deproteinized Bovine Bone Mineral versus rhFGF-2 Alone: 4-Year Extended Follow-Up of a Randomized Controlled Trial

The aim of this study was to evaluate longitudinal outcomes of recombinant human fibroblast growth factor (rhFGF)-2 plus deproteinized bovine bone mineral (DBBM) therapy in comparison with rhFGF-2 alone for treating periodontal intrabony defects. This study describes 4-year follow-up outcomes of the original randomized controlled trial. Intrabony defects in periodontitis patients were treated with rhFGF-2 (control) or rhFGF-2 plus DBBM (test). Clinical, radiographic, and patient-reported outcome (PRO) measures were used to evaluate the outcomes. Thirty-two sites were able to be followed up. At 4 years postoperatively, clinical attachment level (CAL) gains in the test and control groups were 3.5 ± 1.4 mm and 2.7 ± 1.4 mm, respectively, showing significant improvement from preoperative values but no difference between groups. Both groups showed an increase in radiographic bone fill (RBF) over time. At 4 years, the mean value for RBF in the test group (62%) was significantly greater than that in the control group (42%). In 1-2-wall defects, the test treatment yielded significantly greater RBF than the control treatment. No significant difference in PRO scores was noted between the groups. Although no significant difference in CAL gain was found between the groups at the 4-year follow-up, the combination treatment significantly enhanced RBF. Favorable clinical, radiographic outcomes, and PRO in both groups can be maintained for at least 4 years.

Periodontal Disease: The Good, The Bad, and The Unknown

Periodontal disease is classically characterized by progressive destruction of the soft and hard tissues of the periodontal complex, mediated by an interplay between dysbiotic microbial communities and aberrant immune responses within gingival and periodontal tissues. Putative periodontal pathogens are enriched as the resident oral microbiota becomes dysbiotic and inflammatory responses evoke tissue destruction, thus inducing an unremitting positive feedback loop of proteolysis, inflammation, and enrichment for periodontal pathogens. Keystone microbial pathogens and sustained gingival inflammation are critical to periodontal disease progression. However, recent studies have revealed the importance of previously unidentified microbes involved in disease progression, including various viruses, phages and bacterial species. Moreover, newly identified immunological and genetic mechanisms, as well as environmental host factors, including diet and lifestyle, have been discerned in recent years as further contributory factors in periodontitis. These factors have collectively expanded the established narrative of periodontal disease progression. In line with this, new ideologies related to maintaining periodontal health and treating existing disease have been explored, such as the application of oral probiotics, to limit and attenuate disease progression. The role of systemic host pathologies, such as autoimmune disorders and diabetes, in periodontal disease pathogenesis has been well noted. Recent studies have additionally identified the reciprocated importance of periodontal disease in potentiating systemic disease states at distal sites, such as in Alzheimer's disease, inflammatory bowel diseases, and oral cancer, further highlighting the importance of the oral cavity in systemic health. Here we review long-standing knowledge of periodontal disease progression while integrating novel research concepts that have broadened our understanding of periodontal health and disease. Further, we delve into innovative hypotheses that may evolve to address significant gaps in the foundational knowledge of periodontal disease.

Visual and histological evaluation of the effects of trafermin in a dog oronasal fistula model

The standard procedure to treat oronasal fistula in dogs requires tooth extraction to close the fistula; hence, the subject would lose its tooth. In this study, trafermin was applied to four dog models with oronasal fistula to investigate the periodontal tissue regenerative effects of trafermin in the treatment without tooth extraction. A fistula was created along the palatal side of each upper canine tooth. One of the fistulae was filled with trafermin, whereas that on the contralateral side was left unfilled as a control. The results showed a significant decrease in the non-calcified periodontal tissue volume on the trafermin side after the fourth week. In addition, oronasal fistula closure was visually and histologically confirmed at the eighth week on the trafermin side of all four models.

Semelil as Adjunctive Therapy in Chronic Periodontitis: A Preliminary Randomized Controlled Clinical Study

Host modulation therapy is recently employed to improve periodontal treatments outcome. This randomized controlled clinical trial aimed to evaluate the effects of Semelil (ANGIPARS) as an adjunct to non-surgical treatment in patients with chronic periodontitis. Forty-four healthy subjects with moderate to severe chronic periodontitis were enrolled in the study. After completion of phase I periodontal therapy, including oral hygiene instruction, scaling, and root planing, the patients were randomly divided into two groups to receive capsules of Semelil (test) or placebo (control), consuming two capsules a day for three months. Clinical parameters (probing depth [PD], clinical attachment level [CAL], modified sulcular bleeding index [MSBI], modified gingival index [MGI], and plaque index [PI]) and biochemical parameters (interleukin-1β [IL-1β], 8-hydroxy-2-deoxyguanosine [8-OHdG]), and lipid peroxidation [LPO]) were measured at baseline and after completion of treatment. Twenty-five patients completed the study: 15 in the test group and 10 in the control group. All clinical and biochemical parameters were significantly improved from baseline to the final measurements in both groups (p < 0.001). The changes were more pronounced in the test group in comparison to the control group. However, the differences between the groups were significant only for MGI, MSBI, PD, and CAL (p < 0.05). Semelil may reveal promising results as an adjunctive treatment for chronic periodontitis.

Long-term changes in the anterior alveolar bone after orthodontic treatment with premolar extraction: A retrospective study

OBJECTIVES

To evaluate the morphometric changes in maxillary and mandibular anterior alveolar bone after orthodontic treatment and retention for 18-24 months by cone-beam computed tomography (CBCT).

SETTING AND SAMPLE POPULATION

Thirty-four adolescent patients (12 males and 22 females; mean age: 14.29 ± 1.24 years) diagnosed with bimaxillary dentoalveolar protrusion and with extractions of the 4 first premolars were included.

MATERIALS AND METHODS

The labial and lingual (palatal) alveolar bone thickness, height and root length of the maxillary and mandibular anterior teeth were assessed using CBCT imaging at the pre-treatment (T1), post-treatment (T2) and retention phases (T3). Voxel-based superimpositions of the T2 and T3 images were performed, and the distances of incisal and apical movement between T2 and T3 were measured to determine whether relapses occurred.

RESULTS

After orthodontic treatment, the labial and lingual (palatal) bone height decreased significantly (P < .05) and the labial thickness at the crestal (L1), midroot (L2), and apical levels (L3) had no significant change, while the lingual (palatal) bone thickness at all three levels decreased significantly (P < .05). After 18-24 months of retention, the lingual (palatal) height and the lingual (palatal) thickness at the crestal (L1) level increased significantly (P < .05). There were no obvious incisal and apical movements of the anterior teeth between T2 and T3 (P > .05), indicating that no relapses occurred.

CONCLUSIONS

Even though lingual (palatal) alveolar loss occurred due to the orthodontic treatment, the cervical alveolar bone seemed to recover over time. Therefore, appropriate camouflage treatment can be used in patients with bimaxillary dentoalveolar protrusion, and this treatment will not irreversibly deteriorate periodontal health and affect the orthodontic treatment stability.

Efficacy of recombinant human fibroblast growth factor 2 impregnated absorbable collagen membrane in the treatment of Miller's Class I and II gingival recession defects Preliminary results from the first in human clinical trial

Aims:

This study was a single-arm trial to obtain preliminary data on the efficacy of collagen membranes impregnated with recombinant human fibroblast growth factor-2 (rhFGF-2) in the treatment of Miller's Class I and II gingival recessions.

Materials and Methods:

Twenty-one individuals (34 sites) presenting with localized Miller's Class I and II gingival recessions were included in this study. Following a standard surgical protocol, rhFGF-2-impregnated membranes were placed in sites with gingival recession. Clinical parameters such as width of keratinized gingiva (wKG), recession depth (RD), and probing depth were measured at baseline and after therapy completion at 3 and 6 months.

Results:

Most of the sites exhibited favorable clinical healing; the most common complications were persistent edematous and inflamed gingivae beyond 1 week (n = 3), development of residual periodontal pockets (n = 2), and no reduction in RDs (n = 2). Significant improvements in wKG and RD were noted from baseline to 6 months.

Conclusion:

rhFGF-2-impregnated collagen membranes showed promising results in terms of increasing the wKG and recession coverage. A comparison with other standard therapies and agents in subsequent trials may shed more light on the clinical efficacy of this material.

Efficacy of FGF-2 in Periodontal Regeneration in a Case of Severe Intrabony Defect and Furcation Involvement With 15-Month Follow-Up

INTRODUCTION

Several studies have demonstrated that basic fibroblast growth factor (FGF-2) is one of the most effective growth factors for periodontal regeneration. The Ministry of Health, Labor and Welfare in Japan have approved 0.3% human recombinant FGF-2 for periodontal regeneration, and it has been commercially available since 2016. In this case report, a patient was treated with this periodontal regenerative medicine and demonstrated success at 15-month follow-up, as confirmed by dental X-ray and on cone-beam computed tomography (CBCT).

CASE PRESENTATION

A 42-year-old woman with a one by two walled intrabony defect and Class III furcation involvement in tooth #19, and Class II furcation involvement in tooth #18 (lingual) underwent periodontal regenerative surgery with FGF-2 without any bone graft materials. Favorable clinical and radiographic outcomes were noted 15 months after the procedure. The vertical bone defect in tooth #19 showed a clinical attachment level gain of 8 mm. Moreover, CBCT analysis revealed considerable new bone formation in the Class II furcation involvement in tooth #18 and limited bone formation in the Class III furcation involvement in tooth #19.

CONCLUSIONS

This case report indicates that FGF-2 showed a positive outcome in terms of periodontal regeneration in a case of one by two wall intrabony defects with Class III furcation involvement. A complete recovery of Class II furcation involvement was observed without artificial bone graft materials.

Salivary and serum markers of angiogenesis in periodontitis in relation to smoking

OBJECTIVE

Angiogenesis is essential in maintenance of periodontal homeostasis, and it is regulated by growth factors and cytokines, including basic fibroblast growth factor (b-FGF), endoglin, platelet and endothelial cell adhesion molecule (PECAM-1), vascular endothelial growth factor (VEGF), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1). In this study, the salivary and serum concentrations of these angiogenesis-related proteins in relation to smoking and periodontitis were examined.

MATERIAL AND METHODS

Full-mouth periodontal status together with unstimulated whole saliva and serum samples was collected from 78 individuals, including 40 periodontitis patients (20 smokers and 20 nonsmokers) and 38 periodontally healthy controls (20 smokers and 18 nonsmokers). The Luminex®-xMAP™ technique was used for protein analyses.

RESULTS

Concentrations of all tested proteins in saliva as well as VEGF in serum were significantly higher in periodontitis patients than in healthy controls. In smokers, serum concentrations of endoglin (p = 0.017) and sICAM-1 (p = 0.001) were elevated in comparison to nonsmokers. After adjusting for smoking and gender, periodontitis associated significantly with salivary concentrations of b-FGF, PECAM-1, VEGF, sICAM-1, and sVCAM-1 (p < 0.01).

CONCLUSION

Taken together, salivary concentrations of b-FGF, PECAM-1, and VEGF associate with periodontitis. The suppressive effect of smoking on salivary marker levels is limited to periodontitis patients only.

CLINICAL RELEVANCE

Smoking-related suppression of salivary marker levels is observed only in periodontitis patients.

Thyroxine-loaded chitosan/carboxymethyl cellulose/hydroxyapatite hydrogels enhance angiogenesis in in-ovo experiments

Angiogenesis is one of the most important processes in repair and regeneration of many tissues and organs. Blood vessel formation also play a major role in repair of dental tissue(s) after ailments like periodontitis. Here we report the preparation of chitosan/carboxymethyl cellulose/hydroxyapatite based hydrogels, loaded with variable concentrations of thyroxin i.e., 0.1 μg/ml, 0.5 μg/ml and 1 μg/ml. Scanning electron microcopy images (SEM) showed all hydrogels were found to be porous and solution absorption study exhibited high swelling potential in aqueous media. FTIR spectra confirmed that the used materials did not change their chemical identity in synthesized hydrogels. The synthesized hydrogels demonstrated good bending, folding, rolling and stretching abilities. The hydrogels were tested in chick chorioallantoic membrane (CAM) assay to investigate their angiogenic potential. Hydrogel containing 0.1 μg/ml of thyroxine showed maximum neovascularization. For cytotoxicity analyses, preosteoblast cells (MC3T3-E1) were seeded on these hydrogels and materials were found to be non-toxic. These hydrogels with pro-angiogenic activity possess great potential to be used for periodontal regeneration.

Histologic evidence of periodontal regeneration in furcation defects: a systematic review

OBJECTIVE

To systematically review the available histologic evidence on periodontal regeneration in class II and III furcations in animals and humans.

MATERIALS AND METHODS

A protocol including all aspects of a systematic review methodology was developed including definition of the focused question, defined search strategy, study inclusion criteria, determination of outcome measures, screening methods, data extraction and analysis, and data synthesis. The focused question was defined as follows: "What is the regenerative effect obtained by using or not several biomaterials as adjuncts to open flap surgery in the treatment of periodontal furcation defects as evaluated in animal and human histological studies?"

SEARCH STRATEGY

Using the MEDLINE database, the literature was searched for articles published up to and including September 2018: combinations of several search terms were applied to identify appropriate studies. Reference lists of review articles and of the included articles in the present review were screened. A hand search of the most important dental journals was also performed.

CRITERIA FOR STUDY SELECTION AND INCLUSION

Only articles published in English describing animal and human histological studies evaluating the effect of surgical treatment, with or without the adjunctive use of potentially regenerative materials (i.e., barrier membranes, grafting materials, growth factors/proteins, and combinations thereof) for the treatment of periodontal furcation defects were considered. Only studies reporting a minimum of 8 weeks healing following reconstructive surgery were included. The primary outcome variable was formation of periodontal supporting tissues [e.g., periodontal ligament, root cementum, and alveolar bone, given as linear measurements (in mm) or as a percentage of the instrumented root length (%)] following surgical treatment with or without regenerative materials, as determined histologically/histomorphometrically. Healing type and defect resolution (i.e., complete regeneration, long junctional epithelium, connective tissue attachment, connective tissue adhesion, or osseous repair) were also recorded.

RESULTS

In animals, periodontal regeneration was reported in class II and III defects with open flap debridement alone or combined with various types of bone grafts/bone substitues, biological factors, guided tissue regeneration, and different combinations thereof. The use of biological factors and combination approaches provided the best outcomes for class II defects whereas in class III defects, the combination approaches seem to offer the highest regenerative outcomes. In human class II furcations, the best outcomes were obtained with DFDBA combined with rhPDGF-BB and with GTR. In class III furcations, evidence from two case reports indicated very limited to no periodontal regeneration.

CONCLUSIONS

Within their limits, the present results suggest that (a) in animals, complete periodontal regeneration has been demonstrated in class II and class III furcation defects, and (b) in humans, the evidence for substantial periodontal regeneration is limited to class II furcations.

CLINICAL RELEVANCE

At present, regenerative periodontal surgery represents a valuable treatment option only for human class II furcation defects but not for class III furcations.

Acceleration of bone regeneration of horizontal bone defect in rats using collagen-binding basic fibroblast growth factor combined with collagen scaffolds

Background

Basic fibroblast growth factor (bFGF) has been applied for periodontal regeneration. However, the application depends on bone defect morphology because bFGF diffuses rapidly from defect sites. In a previous study, collagen‐binding bFGF (CB‐bFGF) has been shown to enhance bone formation by collagen‐anchoring in the orthopedic field. The aim of this study is to demonstrate the efficacy of CB‐bFGF with collagen scaffolds in bone regeneration of horizontal bone defect.

Methods

Cell proliferation activity and collagen binding activity of CB‐bFGF was confirmed by WST‐8 assay and collagen binding assay, respectively. The retention of CB‐bFGF in the collagen sheet (CS) was measured by fluorescence imaging. The rat horizontal alveolar bone defect model was employed to investigate the efficacy of CB‐bFGF with collagen powder (CP). After 4 and 8 weeks, the regenerative efficacy was evaluated by microcomputed tomography, histological, and immunohistochemical analyses.

Results

CB‐bFGF had a comparable proliferation activity to bFGF and a collagen binding activity. CB‐bFGF was retained in CS longer than bFGF. At 8 weeks postoperation, bone volume, bone mineral content, and new bone area in CB‐bFGF/CP group were significantly increased compared with those in other groups. Furthermore, epithelial downgrowth was significantly suppressed in CB‐bFGF/CP group. At 4 weeks, the numbers of osteocalcin, proliferating cell nuclear antigen, and osteopontin‐positive cells at the regeneration site in CB‐bFGF/CP group were greater than those in other groups.

Conclusions

CB‐bFGF/CP effectively promoted bone regeneration of horizontal bone defect possibly by sustained release of bFGF. The potential of CB‐bFGF composite material for improved periodontal regeneration in vertical axis was shown.

Inhibiting PHD2 in bone marrow mesenchymal stem cells via lentiviral vector-mediated RNA interference facilitates the repair of periodontal tissue defects in SD rats

Hypoxia-inducible factors (HIFs) play an important role in angiogenesis, and they can activate the expression of several downstream angiogenic factors. HIF-1 is a major transcriptor of HIFs, composed of α and β subunits. Prolyl hydroxylase domain-containing protein 2 (PHD2) is the main catabolic enzyme for HIF-1α, and it can accelerate its degradation under normoxic conditions. PHD2 expression in bone marrow mesenchymal stem cells (BMMSCs) of SD rats was down-regulated under normoxic conditions in this study by utilizing lentiviral vector-mediated RNA interference to promote HIF-1α accumulation, thus enhancing the expression of angiogenic factors. A tissue-engineered compound was constructed using the composite collagen membrane of BMMSCs after PHD2 gene silencing to repair periodontal fenestration defects in SD rats. The results of this study indicated that, after PHD2 gene silencing, the osteogenic differentiation of BMMSCs was enhanced in vitro, the resistance of cells to oxidative stress was also validated in vitro, thereby illustrating the promotion of the repair of artificially constructed periodontal tissue defects in rats. The results of this study provide a reference and guidance for future applications of RNA interference in periodontal tissue engineering and serve as a basis for improving the survival of seed cells in recipient tissues.

Functional efficacy of human recombinant FGF-2s tagged with (His)6 and (His-Asn)6 at the N- and C-termini in human gingival fibroblast and periodontal ligament-derived cells

Fibroblast growth factor (FGF) is a multifunctional growth factor that induces cell proliferation, survival, migration, and differentiation in various cell types and tissues. With these biological functions, FGF-2 has been evaluated for clinical use in the regeneration of damaged tissues. The expression of hFGF-2 in Escherichia coli and a purification system using the immobilized metal affinity chromatography (IMAC) is well established to generate a continuous supply of FGF-2. Although hexa-histidine tag (H₆) is commonly used for IMAC purification, hexa-histidine-asparagine tag (HN₆) is also efficient for purification as it is easily exposed on the surface of the protein. In this study, four different tagging constructs of hFGF-2 based on tag positions and types (H₆-FGF2, FGF2-H₆, HN₆-FGF2, and FGF2-HN₆) were designed and expressed under the inducible T7 expression system in E. coli. The experimental conditions of expression and purification of each recombinant protein were optimized. The effective dosages of the recombinant proteins were determined based on the increase of cell proliferation in human gingival fibroblast. ED50s of H₆-FGF2, FGF2-H₆, HN₆-FGF2, and FGF2-HN₆ were determined (4.42 ng/ml, 3.55 ng/ml, 3.54 ng/ml, and 4.14 ng/ml, respectively) and found to be comparable to commercial FGF-2 (3.67 ng/ml). All the recombinant hFGF-2s inhibit the osteogenic induction and mineralization in human periodontal ligament-derived cells. Our data suggested that biological activities of the recombinant hFGF-2 are irrelevant to types and positions of tags, but may have an influence on the expression efficiency and solubility.

Long-term Observation of Regenerated Periodontium Induced by FGF-2 in the Beagle Dog 2-Wall Periodontal Defect Model

The long-term stability and qualitative characteristics of periodontium regenerated by FGF-2 treatment were compared with normal physiological healing tissue controls in a Beagle dog 2-wall periodontal defect model 13 months after treatment by assessing tissue histology and three-dimensional microstructure using micro-computed tomography (μCT). After FGF-2 (0.3%) or vehicle treatment at the defect sites, serial changes in the bone mineral content (BMC) were observed using periodic X-ray imaging. Tissues were harvested at 13 months, evaluated histomorphometrically, and the cortical bone volume and trabecular bone structure of the newly formed bone were analyzed using μCT. FGF-2 significantly increased the BMC of the defect area at 2 months compared with that of the control group, and this difference was unchanged through 13 months. The cortical bone volume was significantly increased by FGF-2, but there was no difference between the groups in trabecular bone structure. Bone maturation was occurring in both groups because of the lower cortical volume and denser trabecular bone than what is found in intact bone. FGF-2 also increased the area of newly formed bone as assessed histomorphometrically, but the ratios of trabecular bone in the defect area were similar between the control and FGF-2 groups. These results suggest that FGF-2 stimulates neogenesis of alveolar bone that is of similar quality to that of the control group. The lengths of the regenerated periodontal ligament and cementum, measured as the distance from the defect bottom to the apical end of the gingival epithelium, and height and area of the newly formed bone in the FGF-2 group were larger than those in the control group. The present study demonstrated that, within the limitation of artificial periodontal defect model, the periodontal tissue regenerated by FGF-2 was maintained for 13 months after treatment and was qualitatively equivalent to that generated through the physiological healing process.

FGF-2 promotes initial osseointegration and enhances stability of implants with low primary stability

OBJECTIVES

The aim of this study was to examine the effect of basic fibroblast growth factor (FGF-2) on osseointegration of dental implants with low primary stability in a beagle dog model.

MATERIALS AND METHODS

Customized titanium implants that were designed to have low contact with the existing bone were installed into the edentulous mandible of beagle dogs. To degrade the primary stability of the implants, the diameters of the bone sockets exceeded the implant diameters. FGF-2 (0.3%) plus vehicle (hydroxypropyl cellulose) or vehicle alone was topically applied to the sockets in the FGF-2 and control groups, respectively. In Study 1, the new bone area and length of new bone-to-implant contact (BIC) were evaluated at 4, 8, and 12 weeks after installation using histomorphometry and scanning electron microscopy. In Study 2, the implant stability quotient (ISQ) values were sequentially measured for 16 weeks using an Osstell system.

RESULTS

The histomorphometric analysis revealed that the new bone area and length of BIC in the FGF-2 group were significantly larger than those in the control group at 4 weeks. Electron microscopic observation showed intimate contact between the mature lamellar bone and the implant surfaces, osseointegration, in both groups. The ISQ values in the FGF-2 group were significantly increased from 6 to 16 weeks compared with those in the control group.

CONCLUSIONS

Taken together, our study demonstrates that FGF-2 promoted new bone formation around the dental implants and subsequent osseointegration, resulting in promotion of stability of implants with low primary stability.

A Randomized Clinical Trial Evaluating rh-FGF-2/β-TCP in Periodontal Defects

Biological mediators have been used to enhance periodontal regeneration. The aim of this prospective randomized controlled study was to evaluate the safety and effectiveness of 3 doses of fibroblast growth factor 2 (FGF-2) when combined with a β-tricalcium phosphate (β-TCP) scaffold carrier placed in vertical infrabony periodontal defects in adult patients. In this double-blinded, dose-verification, externally monitored clinical study, 88 patients who required surgical intervention to treat a qualifying infrabony periodontal defect were randomized to 1 of 4 treatment groups—β-TCP alone (control) and 0.1% recombinant human FGF-2 (rh-FGF-2), 0.3% rh-FGF-2, and 0.4% rh-FGF-2 with β-TCP—following scaling and root planing of the tooth prior to a surgical appointment. Flap surgery was performed with EDTA conditioning of the root prior to device implantation. There were no statistically significant differences in patient demographics and baseline characteristics among the 4 treatment groups. When a composite outcome of gain in clinical attachment of 1.5 mm was used with a linear bone growth of 2.5 mm, a dose response pattern detected a plateau in the 0.3% and 0.4% rh-FGF-2/β-TCP groups with significant improvements over control and 0.1% rh-FGF-2/β-TCP groups. The success rate at 6 mo was 71% in the 2 higher-concentration groups, as compared with 45% in the control and lowest treatment groups. Percentage bone fill in the 2 higher-concentration groups was 75% and 71%, compared with 63% and 61% in the control and lowest treatment group. No increases in specific antibody to rh-FGF-2 were detected, and no serious adverse events related to the products were reported. The results from this multicenter trial demonstrated that the treatment of infrabony vertical periodontal defects can be enhanced with the addition of rh-FGF-2/β-TCP ( ClinicalTrials.gov NCT01728844).

The effects of fluid shear stress on proliferation and osteogenesis of human periodontal ligament cells

Shear stress is one of the main stress type produced by speech, mastication or tooth movement. The mechano-response of human periodontal ligament (PDL) cells by shear stress and the mechanism are largely unknown. In our study, we investigated the effects of fluid shear stress on proliferation, migration and osteogenic potential of human PDL cells. 6dyn/cm(2) of fluid shear stress was produced in a parallel plate flow chamber. Our results demonstrated that fluid shear stress rearranged the orientation of human PDL cells. In addition, fluid shear stress inhibited human PDL cell proliferation and migration, but increased the osteogenic potential and expression of several growth factors and cytokines. Our study suggested that shear stress is involved in homeostasis regulation in human PDL cells. Inhibiting proliferation and migration potentially induce PDL cells to respond to mechanical stimuli in order to undergo osteogenic differentiation.

Periodontal tissue engineering by nano beta-tricalcium phosphate scaffold and fibroblast growth factor-2 in one-wall infrabony defects of dogs

BACKGROUND AND OBJECTIVE

Nanoparticle bioceramics are being investigated for biomedical applications. We fabricated a regenerative scaffold comprising type I collagen and beta-tricalcium phosphate (β-TCP) nanoparticles. Fibroblast growth factor-2 (FGF-2) is a bioeffective signaling molecule that stimulates cell proliferation and wound healing. This study examined the effects, on bioactivity, of a nano-β-TCP/collagen scaffold loaded with FGF-2, particularly on periodontal tissue wound healing.

MATERIAL AND METHODS

Beta-tricalcium phosphate was pulverized into nanosize particles (84 nm) and was then dispersed. A nano-β-TCP scaffold was prepared by coating the surface of a collagen scaffold with a nanosize β-TCP dispersion. Scaffolds were characterized using scanning electron microscopy, compressive testing, cell seeding and rat subcutaneous implant testing. Then, nano-β-TCP scaffold, nano-β-TCP scaffold loaded with FGF-2 and noncoated collagen scaffold were implanted into a dog one-wall infrabony defect model. Histological observations were made at 10 d and 4 wk postsurgery.

RESULTS

Scanning electron microscopy images show that TCP nanoparticles were attached to collagen fibers. The nano-β-TCP scaffold showed higher compressive strength and cytocompatibility compared with the noncoated collagen scaffold. Rat subcutaneous implant tests showed that the DNA contents of infiltrating cells in the nano-β-TCP scaffold and the FGF-2-loaded scaffold were approximately 2.8-fold and 3.7-fold greater, respectively, than in the collagen scaffold. Histological samples from the periodontal defect model showed about five-fold greater periodontal tissue repair following implantation of the nano-β-TCP scaffold loaded with FGF-2 compared with the collagen scaffold.

CONCLUSION

The β-TCP nanoparticle coating strongly improved the collagen scaffold bioactivity. Nano-β-TCP scaffolds containing FGF-2 are anticipated for use in periodontal tissue engineering.

PLAP-1/Asporin Positively Regulates FGF-2 Activity

PLAP-1 is an extracellular matrix protein that is predominantly expressed in the periodontal ligament within periodontal tissue. It was previously revealed that PLAP-1 negatively regulates bone morphogenetic protein 2 and transforming growth factor β activity through direct interactions. However, the interaction between PLAP-1 and other growth factors has not been defined. Here, we revealed that PLAP-1 positively regulates the activity of fibroblast growth factor 2 (FGF-2), a critical growth factor in tissue homeostasis and repair. In this study, we isolated mouse embryonic fibroblasts (MEFs) from Plap-1(-/-) mice generated in our laboratory. Interestingly, Plap-1(-/-) MEFs exhibited enhanced responses to bone morphogenetic protein 2 but defective responses to FGF-2, and Plap-1 transfection into Plap-1(-/-) MEFs rescued these defective responses. In addition, binding assays revealed that PLAP-1 promotes FGF-2-FGF receptor 1 (FGFR1) complex formation by direct binding to FGF-2. Immunocytochemistry analyses revealed colocalization of PLAP-1 and FGF-2 in wild-type MEFs and reduced colocalization of FGF-2 and FGFR1 in Plap-1(-/-) MEFs compared with wild-type MEFs. Taken together, PLAP-1 positively regulates FGF-2 activity through a direct interaction. Extracellular matrix-growth factor interactions have considerable effects; thus, this approach may be useful in several regenerative medicine applications.

Immunolocalization of FGF-2 and VEGF in rat periodontal ligament during experimental tooth movement

Objective

This article aimed at identifying the expression of fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF) in the tension and pressure areas of rat periodontal ligament, in different periods of experimental orthodontic tooth movement.

Methods

An orthodontic force of 0.5 N was applied to the upper right first molar of 18 male Wistar rats for periods of 3 (group I), 7 (group II) and 14 days (group III). The counter-side first molar was used as a control. The animals were euthanized at the aforementioned time periods, and their maxillary bone was removed and fixed. After demineralization, the specimens were histologically processed and embedded in paraffin. FGF-2 and VEGF expressions were studied through immunohistochemistry and morphological analysis.

Results

The experimental side showed a higher expression of both FGF-2 and VEGF in all groups, when compared with the control side (P < 0.05). Statistically significant differences were also found between the tension and pressure areas in the experimental side.

Conclusion

Both FGF-2 and VEGF are expressed in rat periodontal tissue. Additionally, these growth factors are upregulated when orthodontic forces are applied, thereby suggesting that they play an important role in changes that occur in periodontal tissue during orthodontic movement.

Bilayered construct for simultaneous regeneration of alveolar bone and periodontal ligament

Periodontitis is an inflammatory disease that causes destruction of tooth-supporting tissues and if left untreated leads to tooth loss. Current treatments have shown limited potential for simultaneous regeneration of the tooth-supporting tissues. To recreate the complex architecture of the periodontium, we developed a bilayered construct consisting of poly(caprolactone) (PCL) multiscale electrospun membrane (to mimic and regenerate periodontal ligament, PDL) and a chitosan/2wt % CaSO4 scaffold (to mimic and regenerate alveolar bone). Scanning electron microscopy results showed the porous nature of the scaffold and formation of beadless electrospun multiscale fibers. The fiber diameter of microfiber and nanofibers was in the range of 10 ± 3 µm and 377 ± 3 nm, respectively. The bilayered construct showed better protein adsorption compared to the control. Osteoblastic differentiation of human dental follicle stem cells (hDFCs) on chitosan/2wt % CaSO4 scaffold showed maximum alkaline phosphatase at seventh day followed by a decline thereafter when compared to chitosan control scaffold. Fibroblastic differentiation of hDFCs was confirmed by the expression of PLAP-1 and COL-1 proteins which were more prominent on PCL multiscale membrane in comparison to control membranes. Overall these results show that the developed bilayered construct might serve as a good candidate for the simultaneous regeneration of the alveolar bone and PDL.

FGF-2 induces the proliferation of human periodontal ligament cells and modulates their osteoblastic phenotype by affecting Runx2 expression in the presence and absence of osteogenic inducers

The exact phenotype of human periodontal ligament cells (hPDLCs) remains a controversial area. Basic fibroblast growth factor (FGF-2) exhibits various functions and its effect on hPDLCs is also controversial. Therefore, the present study examined the effect of FGF-2 on the growth and osteoblastic phenotype of hPDLCs with or without osteogenic inducers (dexamethasone and β-glycerophosphate). FGF-2 was added to defined growth culture medium and osteogenic inductive culture medium. Cell proliferation, osteogenic differentiation and mineralization were measured. The selected differentiation markers, Runx2, collagen type I, α1 (Col1a1), osteocalcin (OCN) and epidermal growth factor receptor (EGFR), were investigated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Runx2 and OCN protein expression was measured by western blotting. FGF-2 significantly increased the proliferation of hPDLCs, but did not affect alkaline phosphatase activity. RT-qPCR analysis revealed enhanced mRNA expression of Runx2, OCN and EGFR, but suppressed Col1a1 gene expression in the absence of osteogenic inducers, whereas all these gene levels had no clear trend in their presence. The Runx2 protein expression was clearly increased, but the OCN protein level showed no evident trend. The mineralization assay demonstrated that FGF-2 inhibited mineralized matrix deposition with osteogenic inducers. These results suggested that FGF-2 induces the growth of immature hPDLCs, which is a competitive inhibitor of epithelial downgrowth, and suppresses their differentiation into mineralized tissue by affecting Runx2 expression. Therefore, this may lead to the acceleration of periodontal regeneration.

Action Mechanism of Fibroblast Growth Factor-2 (FGF-2) in the Promotion of Periodontal Regeneration in Beagle Dogs

Fibroblast growth factor-2 (FGF-2) enhances the formation of new alveolar bone, cementum, and periodontal ligament (PDL) in periodontal defect models. However, the mechanism through which FGF-2 acts in periodontal regeneration in vivo has not been fully clarified yet. To reveal the action mechanism, the formation of regenerated tissue and gene expression at the early phase were analyzed in a beagle dog 3-wall periodontal defect model. FGF-2 (0.3%) or the vehicle (hydroxypropyl cellulose) only were topically applied to the defect in FGF-2 and control groups, respectively. Then, the amount of regenerated tissues and the number of proliferating cells at 3, 7, 14, and 28 days and the number of blood vessels at 7 days were quantitated histologically. Additionally, the expression of osteogenic genes in the regenerated tissue was evaluated by real-time PCR at 7 and 14 days. Compared with the control, cell proliferation around the existing bone and PDL, connective tissue formation on the root surface, and new bone formation in the defect at 7 days were significantly promoted by FGF-2. Additionally, the number of blood vessels at 7 days was increased by FGF-2 treatment. At 28 days, new cementum and PDL were extended by FGF-2. Moreover, FGF-2 increased the expression of bone morphogenetic protein 2 (BMP-2) and osteoblast differentiation markers (osterix, alkaline phosphatase, and osteocalcin) in the regenerated tissue. We revealed the facilitatory mechanisms of FGF-2 in periodontal regeneration in vivo. First, the proliferation of fibroblastic cells derived from bone marrow and PDL was accelerated and enhanced by FGF-2. Second, angiogenesis was enhanced by FGF-2 treatment. Finally, osteoblastic differentiation and bone formation, at least in part due to BMP-2 production, were rapidly induced by FGF-2. Therefore, these multifaceted effects of FGF-2 promote new tissue formation at the early regeneration phase, leading to enhanced formation of new bone, cementum, and PDL.

Effect of fibroblast growth factor on injured periodontal ligament and cementum after tooth replantation in dogs

PURPOSE

The purpose of this animal study was to perform a histological and histomorphometric analysis in order to elucidate the effect of fibroblast growth factor-2 (FGF-2) on injured periodontal ligament (PDL) and cementum after tooth replantation in dogs.

METHODS

The roots of 36 mandibular premolars from six mongrel dogs were used in this study. The roots were randomly divided into three groups: (1) a positive control group (n=12), in which the PDL was retained; (2) a negative control group (n=12), in which the PDL and the cementum between the notches were removed; and (3) an experimental group (n=12), in which the PDL and the cementum between the notches were removed and the roots were soaked in an FGF-2 solution (30 µg/0.1 mL). After treating the root surfaces, the extracted roots were replanted into extraction sockets. The animals were sacrificed four and eight weeks after surgery for histologic and histomorphometric evaluation.

RESULTS

At four and eight weeks, normal PDLs covered the roots in the positive control group. In the negative control group, most replanted roots showed signs of replacement resorption. In the experimental group, new PDL-like tissue and cementum-like tissue were observed to partially occupy the region between the root surfaces and the newly formed bone. Histomorphometric analysis showed that the mean length of the newly formed cementum-like tissue on the roots treated with FGF-2 was significantly greater than that of the tissue on the roots in the negative control group (four weeks, P=0.008; eight weeks, P=0.042). However, no significant differences were observed between the roots treated with FGF-2 and the negative control roots with respect to newly formed PDL-like tissue.

CONCLUSIONS

The results of this study suggest that use of FGF-2 on injured root surfaces promotes cementogenesis after tooth replacement in dogs.

Tissue engineering for bone regeneration and osseointegration in the oral cavity

OBJECTIVE

The focus of this review is to summarize recent advances on regenerative technologies (scaffolding matrices, cell/gene therapy and biologic drug delivery) to promote reconstruction of tooth and dental implant-associated bone defects.

METHODS

An overview of scaffolds developed for application in bone regeneration is presented with an emphasis on identifying the primary criteria required for optimized scaffold design for the purpose of regenerating physiologically functional osseous tissues. Growth factors and other biologics with clinical potential for osteogenesis are examined, with a comprehensive assessment of pre-clinical and clinical studies. Potential novel improvements to current matrix-based delivery platforms for increased control of growth factor spatiotemporal release kinetics are highlighting including recent advancements in stem cell and gene therapy.

RESULTS

An analysis of existing scaffold materials, their strategic design for tissue regeneration, and use of growth factors for improved bone formation in oral regenerative therapies results in the identification of current limitations and required improvements to continue moving the field of bone tissue engineering forward into the clinical arena.

SIGNIFICANCE

Development of optimized scaffolding matrices for the predictable regeneration of structurally and physiologically functional osseous tissues is still an elusive goal. The introduction of growth factor biologics and cells has the potential to improve the biomimetic properties and regenerative potential of scaffold-based delivery platforms for next-generation patient-specific treatments with greater clinical outcome predictability.

Fibroblast growth factor-2 promotes healing of surgically created periodontal defects in rats with early, streptozotocin-induced diabetes via increasing cell proliferation and regulating angiogenesis

AIM

To evaluate the effects of fibroblast growth factor (FGF)-2 on the healing of surgical periodontal defects in rats with early, streptozotocin-induced diabetes.

MATERIALS AND METHODS

Fifty Wistar rats were assigned to streptozotocin-induced diabetes or non-diabetes group. Periodontal defects were surgically created at maxillary first molars. Defects were treated with hydroxypropyl cellulose (HPC) or FGF-2 with HPC. Defect fill was evaluated by microcomputed tomography. Histological and immunohistochemical analyses were performed.

RESULTS

Compared to vehicle alone, FGF-2 treatment yielded significantly greater bone volume and trabecular thickness in diabetes group. Diabetes group displayed reduced new bone formation and significantly longer epithelial down-growth compared to non-diabetes group. In diabetes group, FGF-2 treatment increased PCNA-positive cells and new bone formation after 2 weeks and suppressed epithelial down-growth, but new cementum formation was minimal even after 4 weeks. In diabetes group, overexpression of vascular endothelial growth factor was evident in cells within connective tissue, and no significant enhancement was observed by FGF-2 treatment. FGF-2 increased the expression of α-smooth muscle actin in diabetes group.

CONCLUSIONS

Treatment of surgical periodontal defects in diabetic rats with the single application of FGF-2 provided beneficial effects primarily on new bone formation via increasing cell proliferation and regulating angiogenesis.

MAPs/bFGF-PLGA microsphere composite-coated titanium surfaces promote increased adhesion and proliferation of fibroblasts

Infection and epithelial downgrowth are two major problems with maxillofacial transcutaneous implants, and both are mainly due to lack of stable closure of soft tissues at transcutaneous sites. Fibroblasts have been shown to play a key role in the formation of biological seals. In this work, titanium (Ti) model surfaces were coated with mussel adhesive proteins (MAPs) utilizing its unique adhesion ability on diverse inorganic and organic surfaces in wet environments. Prepared basic fibroblast growth factor (bFGF)-poly(lactic-co-glycolic acid) (PLGA) microspheres can be easily synthesized and combined onto MAPs-coated Ti surfaces, due to the negative surface charges of microspheres in aqueous solution, which is in contrast to the positive charges of MAPs. Titanium model surfaces were divided into three groups. Group A: MAPs/bFGF-PLGA microspheres composite-coated Ti surfaces. Group B: MAPs-coated Ti surfaces. Group C: uncoated Ti surfaces. The effects of coated Ti surfaces on adhesion of fibroblasts, cytoskeletal organization, proliferation, and extracellular matrix (ECM)-related gene expressions were examined. The results revealed increased adhesion (P < 0.05), enhanced actin cytoskeletal organization, and up-regulated ECM-related gene expressions in groups A and B compared with group C. Increased proliferation of fibroblasts during five days of incubation was observed in group A compared with groups B and C (P < 0.05). Collectively, the results from this in vitro study demonstrated that MAPs/bFGF-PLGA microspheres composite-coated Ti surfaces had the ability to increase fibroblast functionality. In addition, MAPs/bFGF-PLGA microsphere composite-coated Ti surfaces should be studied further as a method of promoting formation of stable biological seals around transcutaneous sites.

Image-based, fiber guiding scaffolds: a platform for regenerating tissue interfaces

In the oral and craniofacial complex, tooth loss is the most commonly acquired disfiguring injury. Among the most formidable challenges of reconstructing tooth-supporting osseous defects in the oral cavity is the regeneration of functional multi-tissue complexes involving bone, ligament, and tooth cementum. Furthermore, periodontal multi-tissue engineering with spatiotemporal orientation of the periodontal ligament (PDL) remains the most challenging obstacle for restoration of physiological loading and homeostasis. We report on the ability of a hybrid computer-designed scaffold--developed utilizing computed tomography--to predictably facilitate the regeneration and integration of dental supporting tissues. Here, we provide the protocol for rapid prototyping, manufacture, surgical implantation, and evaluation of dual-architecture scaffolds for controlling fiber orientation and facilitating morphogenesis of bone-ligament complexes. In contrast to conventional single-system methods of fibrous tissue formation, our protocol supports rigorous control of multi-compartmental scaffold architecture using computational scaffold design and manufacturing by 3D printing, as well as the evaluation of newly regenerated tissue physiology for clinical implementation.

Tissue engineering in periodontal tissue

Periodontitis, a recognized disease worldwide, is bacterial infection-induced inflammation of the periodontal tissues that results in loss of alveolar bone. Once it occurs, damaged tissue cannot be restored to its original form, even if decontaminating treatments are performed. For more than half a century, studies have been conducted to investigate true periodontal regeneration. Periodontal regeneration is the complete reconstruction of the damaged attachment apparatus, which contains both hard tissue (alveolar bone and cementum) and soft tissue (periodontal ligament). Several treatments, including bone grafts, guided tissue regeneration with physical barriers for epithelial cells, and growth factors have been approved for clinical use; however, their indications and outcomes are limited. To overcome these limitations, the concept of "tissue engineering" was introduced. Combination treatment using cells, growth factors, and scaffolds, has been studied in experimental animal models, and some studies have been translated into clinical trials. In this review, we focus on recent progressive tissue engineering studies and discuss future perspectives on periodontal regeneration.

Cooperative effects of FGF-2 and VEGF-A in periodontal ligament cells

We previously demonstrated that topical application of fibroblast growth factor (FGF)-2 enhanced periodontal tissue regeneration. Although angiogenesis is a crucial event for tissue regeneration, the mechanism(s) by which topically applied FGF-2 induces angiogenesis in periodontal tissues has not been fully clarified. In this study, we investigated whether FGF-2 could induce vascular endothelial growth factor (VEGF)-A expression in periodontal ligament (PDL) cells and whether cell-to-cell interactions between PDL cells and endothelial cells could stimulate angiogenesis. FGF-2 induced VEGF-A secretion from MPDL22 cells (mouse periodontal ligament cell line) in a dose-dependent manner. Transwell and wound-healing assays revealed that co-stimulation with FGF-2 plus VEGF-A synergistically stimulated the migration of MPDL22 cells. Interestingly, co-culture of MPDL22 cells with bEnd5 cells (mouse endothelial cell line) also stimulated VEGF-A production from MPDL22 cells and tube formation by bEnd5 cells. Furthermore, time-lapse analysis revealed that MPDL22 cells migrated close to the tube-forming bEnd5 cells, mimicking pericytes. Thus, FGF-2 induces VEGF-A expression in PDL cells and induces angiogenesis in combination with VEGF-A. Cell-to-cell interactions with PDL cells also facilitate angiogenesis.

Effects of bFGF on the Modulation of Apoptosis in Gingival Fibroblasts with Different Host Ages

The purpose of this study was to investigate the effects of basic fibroblast growth factor (bFGF) treatment on the proliferation and apoptosis of cultured gingival fibroblasts (GFs). Human GFs were isolated from the palatal gingival tissues of 16 healthy volunteers ranging in the age from 9 to 35 years old. Cultured GFs were subjected to the analyses for cell proliferation by ELISA assay, gene expression by RT-PCR analysis, and apoptosis potency by caspase-3 assay. The cell proliferation activity and gene expression of type-I collagen and caspase-3 activity were enhanced significantly by the treatment with bFGF in cultured GFs. Furthermore, the activity of caspase-3 in cultured GFs from young subjects was significantly higher than that in GFs from adults. It is shown that bFGF significantly enhances the gene expression of type-I collagen in cultured fibroblasts from human gingival tissues. It also demonstrated that bFGF modulates the apoptosis of periodontal fibroblasts, and the effect is higher in young subjects, indicating a significant role of bFGF in the prevention of scar formation during wound healing.