Enamel matrix derivative gel stimulates signal transduction of BMP and TGF-{beta}

Anti-inflammatory effects of EMD in the presence of biomechanical loading and interleukin-1β in vitro

Enamel matrix derivative (EMD) used to promote periodontal regeneration has been shown to exert anti-inflammatory effects. This in vitro study was performed to investigate if the anti-inflammatory actions of EMD are modulated by the local cellular environment, such as inflammation or occlusal, i.e., biomechanical, loading. Human periodontal ligament cells were seeded on BioFlex plates and incubated with EMD under normal, inflammatory, and biomechanical loading conditions for 1 and 6 days. In order to mimic inflammatory and biomechanical loading conditions in vitro, cells were stimulated with interleukin (IL)-1β and exposed to dynamic tensile strain, respectively. The gene expression of IL-1β, IL-1 receptor antagonist (IL-1RN), IL-6, IL-8, IL-10, and cyclooxygenase (COX)-2 was analyzed by real-time RT-PCR and the IL-6 protein synthesis by enzyme-linked immunoassay. For statistical analysis, Student's t test, ANOVA, and post-hoc comparison tests were applied (p < 0.05). EMD downregulated significantly the expression of IL-1β and COX-2 at 1 day and of IL-6, IL-8, and COX-2 at 6 days in normal condition. In an inflammatory environment, the anti-inflammatory actions of EMD were significantly enhanced at 6 days. In the presence of low biomechanical loading, EMD caused a downregulation of IL-1β and IL-8, whereas high biomechanical loading significantly abrogated the anti-inflammatory effects of EMD at both days. Neither IL-1RN nor IL-10 was upregulated by EMD. These data suggest that high occlusal forces may abrogate anti-inflammatory effects of EMD and should, therefore, be avoided immediately after the application of EMD to achieve best healing results.

Proteomic identification of proteinase inhibitors in the porcine enamel matrix derivative, EMD(®)

BACKGROUND AND OBJECTIVE

The porcine enamel matrix derivative, EMD(®), which is the active component of Emdogain(®), is used widely in periodontics because of its ability to promote the regeneration of soft and hard tissues and to reduce inflammation. Previous studies have used indirect methods to explain its angiogenic and proliferative effects on cells associated with wound healing. In this study we used proteomic techniques to identify proteins in EMD other than amelogenins.

MATERIAL AND METHODS

Proteins in EMD were separated by two-dimensional gel electrophoresis and were identified using mass spectrometry. Proteomic results were validated by western blot analysis of Emdogain.

RESULTS

Fourteen proteins of porcine origin were identified and included the serine and cysteine proteinase inhibitors alpha1-antichymotrypsin and fetuin A, respectively. Alpha1-antichymotrypsin is an acute-phase factor that has been reported to indirectly down-regulate the expression of the gelatinase MMP-9. Fetuin A, a major glycoprotein component of bone and teeth, is a potent inhibitor of ectopic calcification of vascular and soft tissues and has been implicated in both osteogenesis and bone resorption. It also facilitates plasma membrane repair in damaged fibroblasts.

CONCLUSION

EMD contains a number of high-molecular-weight compounds which include the proteinase inhibitors, fetuin A and alpha1-antichymotrypsin.

A review on endogenous regenerative technology in periodontal regenerative medicine

Periodontitis is a globally prevalent inflammatory disease that causes the destruction of the tooth-supporting apparatus and potentially leads to tooth loss. Currently, the methods to reconstitute lost periodontal structures (i.e. alveolar bone, periodontal ligament, and root cementum) have relied on conventional mechanical, anti-infective modalities followed by a range of regenerative procedures such as guided tissue regeneration, the use of bone replacement grafts and exogenous growth factors (GFs), and recently developed tissue engineering technologies. However, all current or emerging paradigms have either been shown to have limited and variable outcomes or have yet to be developed for clinical use. To accelerate clinical translation, there is an ongoing need to develop therapeutics based on endogenous regenerative technology (ERT), which can stimulate latent self-repair mechanisms in patients and harness the host's innate capacity for regeneration. ERT in periodontics applies the patient's own regenerative 'tools', i.e. patient-derived GFs and fibrin scaffolds, sometimes in association with commercialized products (e.g. Emdogain and Bio-Oss), to create a material niche in an injured site where the progenitor/stem cells from neighboring tissues can be recruited for in situ periodontal regeneration. The choice of materials and the design of implantable devices influence therapeutic potential and the number and invasiveness of the associated clinical procedures. The interplay and optimization of each niche component involved in ERT are particularly important to comprehend how to make the desired cell response safe and effective for therapeutics. In this review, the emerging opportunities and challenges of ERT that avoid the ex vivo culture of autologous cells are addressed in the context of new approaches for engineering or regeneration of functional periodontal tissues by exploiting the use of platelet-rich products and its associated formulations as key endogenous resources for future clinical management of periodontal tissue defects.

Emdogain in carcinogenesis: a systematic review of in vitro studies

Emdogain is a commercial product of unknown composition and is clinically used to induce periodontal regeneration. This study aims to review current knowledge of the in vitro effects of Emdogain on oral tissues and, in particular, factors related to carcinoma. A systematic approach was used to review studies from the Embase and Pubmed databases; a total of 76 studies were included. These comprised in vitro studies of the cytokines in, or regulated by, Emdogain and assays designed to study the effects of EMD on human cells in oral tissues or malignant cells. Several studies have shown that EMD regulates the proliferation, migration, adhesion, gene expression, and cytokine production of (pre-)osteoblasts, periodontal fibroblasts, and gingival fibroblasts. However, the effects of EMD on malignant oral cells are not well understood. EMD seems to have broad regulatory effects on malignant cells and on several carcinoma-related factors. Evidence suggests that patients with premalignant or malignant mucosal lesions should not be treated with EMD.

Inorganic Polyphosphate Induces Osteoblastic Differentiation

Inorganic polyphosphate [Poly(P)] is especially prevalent in osteoblasts. We tested the hypothesis that Poly(P) stimulates osteoblastic differentiation and polyphosphate metabolism for bone formation. The osteoblast-like cell line, MC 3T3-E1, was cultured with Poly(P), and gene expression was evaluated by real-time reverse-transcription polymerase chain-reaction. Phosphatase activity and extracellular matrix mineralization were also determined. The role of Poly(P) was assessed in a beagle dog alveolar bone regeneration model. Poly(P) increased osteocalcin, osterix, bone sialoprotein, and tissue non-specific alkaline phosphatase gene expression, with a high level of end-polyphosphatase activity, resulting in low-chain-length Poly(P), inorganic pyrophosphate, and inorganic phosphate production. MC3T3-E1 cells differentiated into mature osteoblasts and showed expression of ectonucleotide pyrophosphatase phosphodiesterase 1, while mouse progressive ankylosis gene expression remained unchanged. Promotion of alveolar bone regeneration was observed in Poly(P)-treated beagle dogs. These findings suggest that Poly(P) induces osteoblastic differentiation and bone mineralization, and acts as a resource for mineralization.

Enamel matrix derivative protein stimulated wound healing via phosphoinositide 3-kinase

BACKGROUND

Enamel matrix derivative (EMD) protein has been clinically used for periodontal regeneration, but the molecular mechanisms are not clear. Previous studies suggested that the activation of phosphoinositide 3-kinase (PI 3-kinase) plays a key role in facilitating cell migration. Given that the migration of osteoblasts is one of the key steps in the wound-healing processes, we hypothesized that EMD protein would stimulate osteoblast migration by activating PI 3-kinase. In this study, we tested this hypothesis using MG-63 cells as model systems to evaluate mechanisms of migration by stimulation with EMD protein.

METHODS

Confluent MG-63 cells were mechanically scratched using a sterilized 1-mm pipette tip that removed the cells within a circular area. The wells were incubated for 24 hours in various stimulation conditions (25, 50, or 100 microg/ml EMD protein) with or without the PI 3-kinase inhibitor wortmannin (1, 10, and 100 nM) or LY294002 (1, 10, and 100 microM). Migrated cells in the wound section were counted by randomly selecting three areas from one well. The activation of PI 3-kinase by EMD protein was evaluated by the phosphorylation of Akt using Western blot analysis.

RESULTS

Although EMD protein did not affect proliferation, it enhanced migration into wounds on MG-63 cells. We showed that EMD protein enhanced the phosphorylation of Akt in a dose-dependent manner. We demonstrated that the PI 3-kinase inhibitors wortmannin and LY294002 blocked migration into wounds and the phosphorylation of Akt enhanced by EMD protein in MG-63 cells.

CONCLUSION

These results demonstrated that the activation of PI 3-kinase plays a key role in the EMD protein-stimulated migration of osteoblasts.

The effect of enamel matrix derivative (Emdogain) on bone formation: a systematic review

This systematic review focused on the question, if and to what extent enamel matrix derivative (Emdogain) [EMD]) promotes the regeneration of bone. The influence of combinations with other biomaterials was additionally evaluated. Twenty histomorphometric studies were included in this systematic review. Main results of the reviewed articles were (i) guide tissue regeneration (GTR) of infrabony defects seems to result in a higher degree of bone regeneration compared to treatment with EMD; (ii) combined therapy (GTR + EMD) of infrabony defects might not lead to better results than GTR therapy alone; (iii) there seems to be no additional benefit of combined therapy (GTR + EMD) in furcation defects over GTR therapy alone; (iv) EMD seems to lead to more bone regeneration of infrabony defects compared to open flap debridement; (v) however, EMD application might result in more bone formation when applied in supporting defects compared to nonsupporting defects; and (vi) EMD does not seem to promote external jaw/parietal bone formation in the titanium capsule model. The results of one study that suggest that EMD increases the initial growth of trabecular bone around endosseous implants by new bone induction need to be confirmed by additional research.

Enamel matrix proteins; old molecules for new applications

Emdogain (enamel matrix derivative, EMD) is well recognized in periodontology, where it is used as a local adjunct to periodontal surgery to stimulate regeneration of periodontal tissues lost to periodontal disease. The biological effect of EMD is through stimulation of local growth factor secretion and cytokine expression in the treated tissues, inducing a regenerative process that mimics odontogenesis. The major (>95%) component of EMD is Amelogenins (Amel). No other active components have so far been isolated from EMD, and several studies have shown that purified amelogenins can induce the same effect as the complete EMD. Amelogenins comprise a family of highly conserved extracellular matrix proteins derived from one gene. Amelogenin structure and function is evolutionary well conserved, suggesting a profound role in biomineralization and hard tissue formation. A special feature of amelogenins is that under physiological conditions the proteins self-assembles into nanospheres that constitute an extracellular matrix. In the body, this matrix is slowly digested by specific extracellular proteolytic enzymes (matrix metalloproteinase) in a controlled process, releasing bioactive peptides to the surrounding tissues for weeks after application. Based on clinical and experimental observations in periodontology indicating that amelogenins can have a significant positive influence on wound healing, bone formation and root resorption, several new applications for amelogenins have been suggested. New experiments now confirm that amelogenins have potential for being used also in the fields of endodontics, bone regeneration, implantology, traumatology, and wound care.

Localized delivery of growth factors for periodontal tissue regeneration: role, strategies, and perspectives

Difficulties associated with achieving predictable periodontal regeneration, means that novel techniques need to be developed in order to regenerate the extensive soft and hard tissue destruction that results from periodontitis. Localized delivery of growth factors to the periodontium is an emerging and versatile therapeutic approach, with the potential to become a powerful tool in future regenerative periodontal therapy. Optimized delivery regimes and well-defined release kinetics appear to be logical prerequisites for safe and efficacious clinical application of growth factors and to avoid unwanted side effects and toxicity. While adequate concentrations of growth factor(s) need to be appropriately localized, delivery vehicles are also expected to possess properties such as protein protection, precision in controlled release, biocompatibility and biodegradability, self-regulated therapeutic activity, potential for multiple delivery, and good cell/tissue penetration. Here, current knowledge, recent advances, and future possibilities of growth factor delivery strategies are outlined for periodontal regeneration. First, the role of those growth factors that have been implicated in the periodontal healing/regeneration process, general requirements for their delivery, and the different material types available are described. A detailed discussion follows of current strategies for the selection of devices for localized growth factor delivery, with particular emphasis placed upon their advantages and disadvantages and future prospects for ongoing studies in reconstructing the tooth supporting apparatus.

Systematic assessment of growth factor treatment on biochemical and biomechanical properties of engineered articular cartilage constructs

OBJECTIVE

To determine the effects of bone morphogenetic protein-2 (BMP-2), insulin-like growth factor (IGF-I), and transforming growth factor-beta1 (TGF-beta1) on the biochemical and biomechanical properties of engineered articular cartilage constructs under serum-free conditions.

METHODS

A scaffoldless approach for tissue engineering, the self-assembly process, was employed. The study consisted of two phases. In the first phase, the effects of BMP-2, IGF-I, and TGF-beta1, at two concentrations and two dosage frequencies each were assessed on construct biochemical and biomechanical properties. In phase II, the effects of growth factor combination treatments were determined. Compressive and tensile mechanical properties, glycosaminoglycan (GAG) and collagen content, histology for GAG and collagen, and immunohistochemistry (IHC) for collagen types I and II were assessed.

RESULTS

In phase I, BMP-2 and IGF-I treatment resulted in significant, >1-fold increases in aggregate modulus, accompanied by increases in GAG production. Additionally, TGF-beta1 treatment resulted in significant, approximately 1-fold increases in both aggregate modulus and tensile modulus, with corresponding increases in GAG and collagen content. In phase II, combined treatment with BMP-2 and IGF-I increased aggregate modulus and GAG content further than either growth factor alone, while TGF-beta1 treatment alone remained the only treatment to also enhance tensile properties and collagen content.

DISCUSSION

This study determined systematically the effects of multiple growth factor treatments under serum-free conditions, and is the first to demonstrate significant increases in both compressive and tensile biomechanical properties as a result of growth factor treatment. These findings are exciting as coupling growth factor application with the self-assembly process resulted in tissue engineered constructs with functional properties approaching native cartilage values.

The role of tissue engineering in articular cartilage repair and regeneration

Articular cartilage repair and regeneration continue to be largely intractable because of the poor regenerative properties of this tissue. The field of articular cartilage tissue engineering, which aims to repair, regenerate, and/or improve injured or diseased articular cartilage functionality, has evoked intense interest and holds great potential for improving articular cartilage therapy. This review provides an overall description of the current state of and progress in articular cartilage repair and regeneration. Traditional therapies and related problems are introduced. More importantly, a variety of promising cell sources, biocompatible tissue engineered scaffolds, scaffoldless techniques, growth factors, and mechanical stimuli used in current articular cartilage tissue engineering are reviewed. Finally, the technical and regulatory challenges of articular cartilage tissue engineering and possible future directions are also discussed.

Emdogain stimulates matrix degradation by osteoblasts

Emdogain has been used clinically for periodontal regeneration, although the underlying molecular mechanisms are not clear at present. In this study, we hypothesized that Emdogain stimulated degradation of type I collagen via osteoblasts. We showed that Emdogain enhanced cell-mediated degradation of type I collagen in an MMP-dependent manner. Although MG-63 cells spontaneously produced a zymogen form of MMP-1, treatment with Emdogain significantly induced the generation of the active form of this enzyme. We demonstrated that MMP-3 was produced from MG63 cells in response to Emdogain in a MEK1/2-dependent manner. Concomitantly, blocking of MEK1/2 activation by U0126 significantly inhibited the generation of the active form of MMP-1 without affecting the total production of this collagenase. These results suggest that Emdogain facilitates tissue regeneration through the activation of the collagenase, MMP-1, that degrades matrix proteins in bone tissue microenvironments.

Enamel matrix derivative induces connective tissue growth factor expression in human osteoblastic cells

BACKGROUND

Enamel matrix derivative (EMD) stimulates the production of transforming growth factor-beta (TGF-beta), which has been suggested to play a role in mediating the effects of EMD in periodontal tissue regeneration. Connective tissue growth factor (CTGF) is a mediator of TGF-beta and promotes cell development. The interaction between EMD and CTGF is unknown. This study explored the effects of EMD on CTGF expression in human osteoblastic cells and whether the interaction is modulated by the TGF-beta signaling pathway. Also, the roles of CTGF in cell proliferation, cell cycle progression, and mineralized nodule formation of EMD-induced osteoblastic cultures were examined.

METHODS

Human osteoblastic cells (Saos-2) were treated with 25 to 100 microg/ml EMD with or without the addition of TGF-beta inhibitor. CTGF mRNA expression was detected by reverse transcription-polymerase chain reaction (RT-PCR), and CTGF protein levels were assayed by Western blot analysis. In addition, cell cycle progression and DNA synthesis were determined by flow cytometry and 5-bromo-2'-deoxyuridine (BrdU) incorporation following EMD treatment with or without CTGF antibody. Mineralization was examined by alizarin red staining and quantified by elution with cetylpyridinium chloride.

RESULTS

Western blot and RT-PCR analysis demonstrated a dose-dependent increase of CTGF expression by EMD. EMD-induced CTGF expression was reduced significantly in the presence of TGF-beta inhibitor. Cell cycle and BrdU analysis revealed an increase in cell proliferation following EMD treatment, which was due to an increase in the percentage of cells in the G2/M phase of the cell cycle. No significant effect was found when anti-CTGF antibody was added. Conversely, mineralization was inhibited significantly in EMD-treated cultures in the presence of anti-CTGF antibody.

CONCLUSIONS

EMD stimulates CTGF expression, and the interaction is modulated via TGF-beta in osteoblastic cells. Also, CTGF affects EMD-induced osteoblastic mineralization but not cell proliferation. To our knowledge, these results provide novel insight into EMD-CTGF interaction, two biomodifiers that have therapeutic relevance to tissue engineering and regeneration.

In vitro biologic response of human bone marrow stromal cells to enamel matrix derivative

BACKGROUND

In vitro investigations suggest that enamel matrix derivative (EMD) may affect the biologic response of periodontal-related cells, including osteoblasts and their precursors, the bone marrow stromal cells (BMSCs), which could play a crucial role in the regenerative process. In this study, we investigated the effects of EMD on human BMSCs.

METHODS

Primary cultures of BMSCs were obtained from bone marrow samples of healthy donors. Cell proliferation and osteogenic marker expression in response to serial dilutions of EMD (12.5, 25, and 50 microg/ml) were assessed. Cell growth was measured by 3H-thymidine incorporation and type I collagen synthesis by immunoblotting. Alkaline phosphatase (AP)-specific activity in the early phase (7 days), in vitro mineralization by von Kossa staining and calcium quantification, and osteocalcin levels at prolonged times (3 weeks) also were evaluated.

RESULTS

EMD stimulated BMSC growth in a dose-dependent manner. When EMD 50 microg/ml was followed over time, the highest proliferative effect was evident at 24 hours (3.4-fold of the control). Type I collagen level was significantly lower than the control after a 7-day incubation with EMD 50 microg/ml. AP activity was reduced in a dose-dependent manner down to 55% of the control. Also, the extracellular matrix mineralization decreased in EMD-treated cells with respect to the control, whereas only a slight, not significant, decrease in osteocalcin levels was found.

CONCLUSIONS

EMD significantly increased BMSC growth and simultaneously decreased their osteogenic differentiation. The clinical efficacy of EMD in regenerating periodontal tissues can be attributed, in part, to the biologic effects exerted on the bone marrow stromal component of resident cells.

The enamel matrix derivative (Emdogain) enhances human tongue carcinoma cells gelatinase production, migration and metastasis formation

Enamel matrix derivative Emdogain (EMD) is widely used in periodontal treatment to regenerate lost connective tissue and to improve the attachment of the teeth. Gelatinases (MMP-2 and -9) have an essential role in the promotion and progression of oral cancer growth and metastasis formation. We studied the effects of EMD on human tongue squamous cell carcinoma (HSC-3) cells in vitro and in vivo. In vitro, EMD (100 microg/ml and 200 microg/ml) remarkably induced the MMP-2 and -9 production from HSC-3 cells analysed by zymography and enzyme-linked immunosorbent assay. EMD also slightly induced the MMP-2 and -9 production from benign human mucosal keratinocytes (HMK). Furthermore, EMD clearly induced the transmigration of HSC-3 cells but had no effect on the HMK migration in transwell assays. The in vitro wound closure of HSC-3 cells was notably accelerated by EMD, whereas it had only minor effect on the wound closure of HMKs. The migration of both cell lines was inhibited by a selective cyclic anti-gelatinolytic peptide CTT-2. EMD had no effect on HSC-3 cell proliferation or apoptosis and only a limited effect on cell attachment to various extracellular matrix components. The in vivo mice experiment revealed that EMD substantially induced HSC-3 xenograft metastasis formation. Our results suggest that the use of EMD for patients with oral mucosal carcinomas or premalignant lesions should be carefully considered, possibly avoided.

The potential use of enamel matrix derivative for in situ anterior cruciate ligament tissue engineering: a translational in vitro investigation

Polyester scaffolds have been used as an alternative to autogenous tissues for the reconstruction of the anterior cruciate ligament (ACL). They are biocompatible and encourage tissue infiltration, leading to neoligament formation. However, rupture can occur, caused by abrasion of the scaffold against the bone tunnels through which it is implanted. Good early tissue induction is therefore considered essential to protect the scaffold from this abrasion. Enamel matrix derivative (EMD) is used clinically in the treatment of periodontal disease. It is a complex mix of proteins with growth factor-like activity, which enhances periodontal ligament fibroblast attachment, proliferation, and differentiation, leading to the regeneration of periodontal bone and ligament tissues. We hypothesized that EMD might, in a similar manner, enhance tissue induction around scaffolds used in ACL reconstruction. This preliminary investigation adopted a translational approach, modelling in vitro 3 possible clinical modes of EMD administration, to ascertain the suitability of each protocol for application in an animal model or clinically. Preliminary investigations in monolayer culture indicated that EMD had a significant dose-dependent stimulatory effect (p < 0.05, n = 6) on the proliferation of bovine primary synovial cells. However, pre-treating culture plates with EMD significantly inhibited cell attachment (p < 0.01, n = 6). EMD's effects on synovial cells, seeded onto ligament scaffolds, were then investigated in several in vitro experiments modelling 3 possible modes for clinical EMD administration (pre-, intra-, and post-operative). In the pre-operative model, EMD was adsorbed onto scaffolds before the addition of cells. In the intra-operative model, EMD and cells were added simultaneously to scaffolds in the culture medium. In the post-operative model, cells were pre-seeded onto scaffolds before EMD was administered. EMD significantly inhibited cell adhesion in the pre-operative model (p < 0.05, n = 6) and had no significant benefit in the intra-operative model. In the post-operative model, the addition of EMD to previously cell-seeded scaffolds significantly increased their total deoxyribonucleic acid content (p < 0.01, n = 5). EMD's stimulative effect on cell proliferation in vitro suggests that it may accelerate scaffold colonization by cells (and in turn tissue induction) in situ. However, its inhibitory effect on synovial cell attachment in vitro implies that it may only be suited to post-operative administration.

The molecular control of and clinical variations in root formation

Roots of teeth perform critical functions to anchor the teeth in the jaws and transmit the masticatory forces in such a way as to minimize fracture and wear of the dentition. Tooth root development involves a variety of cell types, epithelial-mesenchymal interactions, the enumeration of specialized extracellular matrices, processing of these matrices and strict control over the microenvironment to allow the cementum and dentin to mineralize. While many of the specific molecular mechanisms involved in root formation remain poorly understood, our knowledge of these events and pathways has advanced markedly over the past decade. The molecular bases of many hereditary conditions having associated dental root anomalies are now known. Therapeutic approaches based on the molecular biology of root formation have and will continue to emerge and be translated into improved clinical care. The purpose of this study was to review our knowledge regarding developmental defects of root formation, the molecular mechanisms involved, and the impact of root variants on clinical dentistry.

Gene profile in periodontal ligament cells and clones with enamel matrix proteins derivative

AIM

Evaluate enamel matrix proteins derivative effect on gene expression profiles in cultured human periodontal ligament cell population and its clones.

MATERIAL AND METHODS

Human periodontal ligament (PDL) cells were explanted. Cell cloning was performed and clones classified into fibroblastic (FB) and mineralized tissue forming (MTF) according to their capacity to express alkaline phosphatase and form mineralized tissue. All cell cultures were grown for 7 days, with and without enamel proteins added to the medium. Following RNA extraction, expression profiling was performed by hybridization with a DNA micro-array. Selected genes differed from the control at a significant level smaller than p<0.01.

RESULTS

Enamel proteins induced major qualitative changes in mRNA expression in all PDL cell populations, differently affecting the entire PDL cell population and its clones. In the entire PDL cell population, enamel proteins significantly enhanced PDL cell function, with a general effect on enhanced cell functional metabolism.

CONCLUSIONS

Enamel proteins enhanced gene expression responsible for protein and mineralized tissue synthesis in the entire PDL population. In the MTF clones, nucleic acid metabolism, protein metabolism and signal transduction related genes were up-regulated, while in the FB clones, up-regulated genes were related to cell adhesion, nucleic acid metabolism and signal transduction.

Human dental follicle cells acquire cementoblast features under stimulation by BMP-2/-7 and enamel matrix derivatives (EMD) in vitro

The dental follicle (DF) surrounding the developing tooth germ is an ectomesenchymal tissue composed of various cell populations derived from the cranial neural crest. Human dental follicle cells (HDFC) are believed to contain precursor cells for cementoblasts, periodontal ligament cells, and osteoblasts. Bone morphogenetic proteins (BMPs) produced by Hertwig's epithelial root sheath or present in enamel matrix derivatives (EMD) seem to be involved in the control of DF cell differentiation, but their precise function remains largely unknown. We report the immunolocalization of STRO-1 (a marker of multipotential mesenchymal progenitor cells) and BMP receptors (BMPR) in DF in vivo. In culture, HDFC co-express STRO-1/BMPR and exhibit multilineage properties. Incubation with rhBMP-2 and rhBMP-7 or EMD for 24 h increases the expression of BMP-2 and BMP-7 by HDFC. Long-term stimulation of these cells by rhBMP-2 and/or rhBMP-7 or EMD significantly increases alkaline phosphatase activity (AP) and mineralization. Expression of cementum attachment protein (CAP) and cementum protein-23 (CP-23), two putative cementoblast markers, has been detected in EMD-stimulated whole DF and in cultured HDFC stimulated with EMD or BMP-2 and BMP-7. RhNoggin, a BMP antagonist, abolishes AP activity, mineralization, and CAP/CP-23 expression in HDFC cultures and the expression of BMP-2 and BMP-7 induced by EMD. Phosphorylation of Smad-1 and MAPK is stimulated by EMD or rhBMP-2. However, rhNoggin blocks only Smad-1 phosphorylation under these conditions. Thus, EMD may activate HDFC toward the cementoblastic phenotype, an effect mainly (but not exclusively) involving both exogenous and endogenous BMP-dependent pathways.

Effect of Mineral Trioxide Aggregate Cements on Transforming Growth Factor β1 and Bone Morphogenetic Protein Production by Human Fibroblasts In Vitro

The aim of this study was to evaluate and compare the effects of two commercial mineral trioxide aggregate (MTA) cements (ProRoot MTA and MTA Angelus) on transforming growth factor (TGF)-beta1 and bone morphogenetic protein (BMP)-2 levels produced by cultured human gingival fibroblasts (HGFs). Human gingival tissues were obtained from individuals with healthy periodontium. HGFs were grown at 37 degrees C in humidified atmosphere of 5% CO(2) in Dulbecco's modified Eagle's medium, supplemented with 10% fetal calf serum, penicillin, and streptomycin. After 24 and 72 hours of exposure to the MTA products, HGF viability was determined by using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide assay. TGF-beta1 and BMP-2 levels in cell-free culture media were determined by enzyme-linked immunosorbent assay. Cell viability of the test groups was significantly lower than that of control at 24 and 72 hours (p < 0.05) but showed an increase at 72 hours (p < 0.05). Both test groups showed increased TGF beta-1 levels at 72 hours (p < 0.05), whereas the MTA Angelus group displayed higher TGF beta-1 levels than control and ProRoot MTA groups at 24 and 72 hours (p < 0.05). At 24 hours, BMP-2 levels of the ProRoot group were significantly higher than that of MTA Angelus (p < 0.05). Both test materials increased the BMP-2 levels within time (p < 0.05) and displayed similar levels at 72 hours (p > 0.05). These results suggest that both MTA products are capable of stimulating HGF to produce BMP-2, whereas the stimulatory effect for TGF beta-1 is material dependent.

The application of an enamel matrix protein derivative (Emdogain) in regenerative periodontal therapy: a review

Regenerative periodontal therapy aims at reconstitution of the lost periodontal structures such as new formation of root cementum, periodontal ligament and alveolar bone. Findings from basic research indicate that enamel matrix protein derivative (EMD) has a key role in periodontal wound healing. Histological results from animal and human studies have shown that treatment with EMD promotes periodontal regeneration. Moreover, clinical studies have indicated that treatment with EMD positively influences periodontal wound healing in humans. This review aims to present an overview of evidence-based clinical indications for regenerative therapy with EMD.

Advances in defining regulators of cementum development and periodontal regeneration

Substantial advancements have been made in defining the cells and molecular signals that guide tooth crown morphogenesis and development. As a result, very encouraging progress has been made in regenerating crown tissues by using dental stem cells and recombining epithelial and mesenchymal tissues of specific developmental ages. To date, attempts to regenerate a complete tooth, including the critical periodontal tissues of the tooth root, have not been successful. This may be in part due to a lesser degree of understanding of the events leading to the initiation and development of root and periodontal tissues. Controversies still exist regarding the formation of periodontal tissues, including the origins and contributions of cells, the cues that direct root development, and the potential of these factors to direct regeneration of periodontal tissues when they are lost to disease. In recent years, great strides have been made in beginning to identify and characterize factors contributing to formation of the root and surrounding tissues, that is, cementum, periodontal ligament, and alveolar bone. This review focuses on the most exciting and important developments over the last 5 years toward defining the regulators of tooth root and periodontal tissue development, with special focus on cementogenesis and the potential for applying this knowledge toward developing regenerative therapies. Cells, genes, and proteins regulating root development are reviewed in a question-answer format in order to highlight areas of progress as well as areas of remaining uncertainty that warrant further study.

Emdogain-gel stimulates proliferation of odontoblasts and osteoblasts

OBJECTIVE

The purpose of this study was to determine whether a premixed form of enamel matrix derivative (EMD), Emdogain-gel, has the same property as the original formula of EMD in stimulating the proliferation of osteoblasts and odontoblasts.

STUDY DESIGN

Osteoblast cell line (MC3T3) and odontoblast cell line (MDPC) were cultured in the 6-well culture plates and treated in 4 different groups: (1) culture medium control, (2) 100 microg/mL Emdogain-gel directly added to the culture medium, (3) culture medium with a culture plate insert, and (4) 100 microg/mL Emdogain-gel added onto a culture plate insert. The culture plate insert prevented direct contact between Emdogain-gel and the cells. After 3-day incubation, cell morphology was examined and the total cell number per well was counted. Data were analyzed using 1-way ANOVA.

RESULTS

Emdogain-gel significantly increased cell number of both osteoblasts and odontoblasts regardless the presence of the culture plate insert.

CONCLUSION

Emdogain-gel stimulates cell proliferation of odontoblasts and osteoblasts. The direct contact between Emdogain-gel and cells is not required. Heat treatment of EMD and premix with propylene glycol alginate did not change its property of releasing bioactive molecules for promoting cell proliferation.

Treatment of Intrabony Defects With an Enamel Matrix Protein Derivative or Bioabsorbable Membrane: An 8-Year Follow-Up Split-Mouth Study

BACKGROUND

Treatments with either an enamel matrix protein derivative (EMD) or guided tissue regeneration (GTR) have been shown to promote periodontal regeneration. However, until recently, only limited data have been available on the long-term clinical results following these regenerative techniques. Therefore, the aim of this study was to present the 8-year results of a prospective, controlled, split-mouth clinical study evaluating the treatment of intrabony defects with EMD or GTR.

METHODS

Ten patients, each of whom displayed one pair of intrabony defects located contralaterally in the same jaw, were randomly treated with EMD or with GTR by means of bioabsorbable membranes. The following clinical parameters were evaluated at baseline and at 1 and 8 years after treatment: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). The primary outcome variable was CAL. No statistically significant differences between the groups were found at baseline.

RESULTS

The sites treated with EMD demonstrated a mean CAL change from 9.5 +/- 1.2 mm to 6.3 +/- 1.3 mm (P <0.001) and 6.7 +/- 1.6 mm (P <0.001) at 1 and 8 years, respectively. No statistically significant differences were found between the 1- and 8-year results. Sites treated with GTR showed a mean CAL change from 9.7 +/- 1.3 mm to 6.7 +/- 0.9 mm (P <0.001) at 1 year and 6.8 +/- 1.2 mm (P <0.001) at 8 years. The CAL change between 1 and 8 years did not present statistically significant differences. Between the treatment groups, no statistically significant differences in any of the investigated parameters were observed at 1 and at 8 years. However, the study does not have the statistical power to rule out the possibility of a difference between the two groups.

CONCLUSIONS

Within their limits, the present results indicate the following: 1) the clinical improvements obtained following treatment with EMD or GTR can be maintained over a period of 8 years; and 2) further studies of much higher power need to be performed to support equivalence.

Porcine Enamel Protein Fractions Contain Transforming Growth Factor-β1

BACKGROUND

Enamel extracts are biologically active and capable of inducing osteogenesis and cementogenesis, but the specific molecules carrying these activities have not been ascertained. The purpose of this study was to identify osteogenic factors in porcine enamel extracts.

METHODS

Enamel proteins were separated by size-exclusion chromatography into four fractions, which were tested for their osteogenic activity on osteoblast-like cells (ST2) and human periodontal ligament (HPDL) cells.

RESULTS

Fraction 3 (Fr.3) and a transforming growth factor-beta 1 (TGF-beta1) control reduced alkaline phosphatase (ALP) activity in ST2 but enhanced ALP activity in HPDL cells. The enhanced ALP activity was blocked by anti-TGF-beta antibodies. Furthermore, using a dual-luciferase reporter assay, we demonstrated that Fr.3 can induce the promoter activity of the plasminogen activator inhibitor type 1 (PAI-1) gene.

CONCLUSION

These results show that the osteoinductive activity of enamel extracts on HPDL cells is mediated by TGF-beta1.

The 17-kDa sheath protein in enamel proteins induces cementum regeneration in experimental cavities created in a buccal dehiscence model of dogs

BACKGROUND AND OBJECTIVE

Commercially available enamel proteins, such as Emdogain, are clinically used for periodontal regeneration. However, the real mechanisms behind the bioactivities of enamel proteins is still unclear, as enamel proteins have multicomponents. The purpose of this in vivo study was to identify the cementum regeneration-promoting factor in enamel proteins that is clinically used for periodontal regeneration to induce cementum-promotive and osteopromotive activities.

MATERIAL AND METHODS

Cementum regeneration, which is an important part of periodontal regeneration, was examined in experimental cavities prepared on a buccal dehiscence model of dogs. The purification of enamel protein with cementum regeneration activity was carried out by gel filtration and ion exchange chromatographies of newly formed secretory enamel.

RESULTS

Cementum regeneration activity was found in the aggregate comprising 13-17-kDa sheath proteins along with a small amount of amelogenins, found in the newly formed secretory enamel. In these proteins, cementum regeneration activity was detected upon application of the 17-kDa sheath protein, but not by other lower molecular-weight sheath proteins and amelogenins. However, the purified 17-kDa sheath protein induced cementum regeneration activity only in a small area, although the regenerated cementum was thick. The activity of the 17-kDa sheath protein was believed not to have been a result of contamination by growth factors such as transforming growth factor-beta1 (TGF-beta1) found in the enamel protein, as the application of TGF-beta1 induced weak cementum regeneration activity.

CONCLUSION

It is concluded that the 17-kDa sheath protein itself exhibits cementum regeneration activity, although other factors may be needed to demonstrate its full ability.

Gene-enhanced tissue engineering for dental hard tissue regeneration: (2) dentin-pulp and periodontal regeneration

Potential applications for gene-based tissue engineering therapies in the oral and maxillofacial complex include the delivery of growth factors for periodontal regeneration, pulp capping/dentin regeneration, and bone grafting of large osseous defects in dental and craniofacial reconstruction. Part 1 reviewed the principals of gene-enhanced tissue engineering and the techniques of introducing DNA into cells. This manuscript will review recent advances in gene-based therapies for dental hard tissue regeneration, specifically as it pertains to dentin regeneration/pulp capping and periodontal regeneration.

Use of growth factors to modify osteoinductivity of demineralized bone allografts: lessons for tissue engineering of bone

Biologically active bone graft substitute materials are needed for repair and regeneration of skeletal tissues. Current approaches are focused on the use of osteoinductive agents, including bone morphogenetic proteins (BMP) in combination with biodegradable carriers. Demineralized freeze-dried bone allograft (DFDBA) can provide an osteoconductive surface and, at the same time, function as a time-release carrier for BMP. Donor variability, however, limits the predictability of DFDBA as an osteoinductive material. This article examines the use of growth factors, including platelet-rich plasma, platelet-derived growth factor, enamel matrix derivatives, and BMP-2, to enhance the osteoinductive properties of human DFDBA.

The effect of the amelogenin fraction of enamel matrix proteins on fibroblast-mediated collagen matrix reorganization

Enamel matrix proteins (EMP), extracted from developing porcine teeth, promote not only periodontal regeneration but also cutaneous wound healing presumably via the amelogenin fraction. Because it is unclear whether the effect of EMP can be ascribed to amelogenins, we compared EMP with recombinant amelogenin in the relaxed dermal equivalent (DE) in vitro model for early wound contraction. EMP and recombinant porcine amelogenin (rP172) at 1 mg/ml were incorporated into DEs composed of human dermal fibroblasts and a type I collagen matrix. The area reduction, as a measure of contraction, as well as fibroblast numbers and TGF-beta1 levels, were quantified over 7 days in culture in the presence of 10% foetal bovine serum. Both EMP and recombinant amelogenin increased contraction (p < 0.005) and fibroblast numbers (p < 0.005) compared with controls (acetic acid vehicle and 1mg/ml porcine serum albumin) and the positive control TGF-beta1 added at 10 ng/ml. Increased contraction with EMP and recombinant amelogenin was most pronounced after the first day of incubation and was associated with elevated (p < 0.005) TGF-beta1 levels in conditioned medium. In conclusion, the amelogenin component of EMP augmented fibroblast-driven collagen matrix remodelling, at least partially, by increasing the endogenous production of TGF-beta1. These effects of EMP/amelogenin may be beneficial for cutaneous wound healing.