Mitogenic, chemotactic, and synthetic responses of rat periodontal ligament fibroblastic cells to polypeptide growth factors in vitro

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.

Twenty-five years of recombinant human growth factors rhPDGF-BB and rhBMP-2 in oral hard and soft tissue regeneration

Contemporary oral tissue engineering strategies involve recombinant human growth factor approaches to stimulate diverse cellular processes including cell differentiation, migration, recruitment, and proliferation at grafted areas. Recombinant human growth factor applications in oral hard and soft tissue regeneration have been progressively researched over the last 25 years. Growth factor-mediated surgical approaches aim to accelerate healing, tissue reconstruction, and patient recovery. Thus, regenerative approaches involving growth factors such as recombinant human platelet-derived growth factor-BB (rhPDGF-BB) and recombinant human bone morphogenetic proteins (rhBMPs) have shown certain advantages over invasive traditional surgical approaches in severe hard and soft tissue defects. Several clinical studies assessed the outcomes of rhBMP-2 in diverse clinical applications for implant site development and bone augmentation. Current evidence regarding the clinical benefits of rhBMP-2 compared to conventional therapies is inconclusive. Nevertheless, it seems that rhBMP-2 can promote faster wound healing processes and enhance de novo bone formation, which may be particularly favorable in patients with compromised bone healing capacity or limited donor sites. rhPDGF-BB has been extensively applied for periodontal regenerative procedures and for the treatment of gingival recessions, showing consistent and positive outcomes. Nevertheless, current evidence regarding its benefits at implant and edentulous sites is limited. The present review explores and depicts the current applications, outcomes, and evidence-based clinical recommendations of rhPDGF-BB and rhBMPs for oral tissue regeneration.

Local Concentrations of TGF-β1 and IGF-1 Appear Determinant in Regulating Bone Regeneration in Human Postextraction Tooth Sockets

Healing after tooth extraction involves a series of reparative processes affecting both alveolar bone and soft tissues. The aim of the present study was to investigate whether activation of molecular signals during the healing process confers a regenerative advantage to the extraction socket soft tissue (ESsT) at 8 weeks of healing. Compared to subepithelial connective tissue graft (CTG), qRT-PCR analyses revealed a dramatic enrichment of the ESsT in osteogenic differentiation markers. However, ESsT and CTG shared characteristics of nonspecialized soft connective tissue by expressing comparable levels of genes encoding abundant extracellular matrix (ECM) proteins. Genes encoding the transforming growth factor-β1 (TGF-β1) and its receptors were strongly enriched in the CTG, whereas the transcript for the insulin-like growth factor-1 (IGF-1) showed significantly high and comparable expression in both tissues. Mechanical stimulation, by the means of cyclic strain or matrix stiffness applied to primary ESsT cells (ESsT-C) and CTG fibroblasts (CTG-F) extracted from the tissue samples, revealed that stress-induced TGF-β1 not exceeding 2.3 ng/mL, as measured by ELISA, in combination with IGF-1 up to 2.5 ng/mL was able to induce the osteogenic potential of ESsT-Cs. However, stiff matrices (50 kPa), upregulating the TGF-β1 expression up to 6.6 ng/mL, caused downregulation of osteogenic gene expression in the ESsT-Cs. In CTG-Fs, endogenous or stress-induced TGF-β1 ≥ 4.6 ng/mL was likely responsible for the complete lack of osteogenesis. Treatment of ESsT-Cs with TGF-β1 and IGF-1 proved that, at specific concentrations, the two growth factors exhibited either an inductive-synergistic or a suppressive activity, thus determining the osteogenic and mineralization potential of ESsT-Cs. Taken together, our data strongly warrant the clinical exploration of ESsT as a graft in augmentative procedures during dental implant placement surgeries.

PDGF-BB-enriched collagen matrix to treat multiple gingival recessions with the tunneled coronally advanced flap

BACKGROUND

With technological advancements in reconstructive periodontology, traditional protocols for the treatment of gingival recessions (GRs) can be challenged. This manuscript presents preliminary findings of a novel minimally-invasive approach for the regenerative treatment of multiple adjacent GR defects.

METHODS

Two healthy adults were treated as part of this study. Multiple adjacent GRs in both subjects (1 in the mandible, and 1 in the maxilla) were treated employing a tunneled coronally advanced flap (TCAF) design, with the application of a cross-linked collagen matrix (CCM) that was enriched with recombinant human platelet-derived growth factor-BB (PDGF-BB) that was also applied on the prepared root surfaces. Clinical, ultrasonographic, esthetic, and patient-reported outcomes were observed at approximately 6- and 18-month time points.

RESULTS

All sites healed uneventfully after the treatments. Complete root coverage was achieved and maintained throughout the follow-up observations, from 6 to 18 months. Patients reported minimal discomfort and reduction of dentinal hypersensitivity at the augmented sites. The areas augmented with CCM + PDGF-BB revealed an increased soft tissue thickness relative to baseline (pretreatment) measures, as well as reduction in the level of the facial bone dehiscences.

CONCLUSION

This article describes the success of two cases of a novel minimally invasive regenerative approach for the treatment of multiple adjacent GR defects by the TCAF, using a CCM loaded with PDGF-BB. This approach offers potential as a minimally-invasive method to repair multiple adjacent GRs.

Platelet-Rich Plasma as an Alternative to Xenogeneic Sera in Cell-Based Therapies: A Need for Standardization

There has been an explosion in scientific interest in using human-platelet-rich plasma (PRP) as a substitute of xenogeneic sera in cell-based therapies. However, there is a need to create standardization in this field. This systematic review is based on literature searches in PubMed and Web of Science databases until June 2021. Forty-one studies completed the selection criteria. The composition of PRP was completely reported in less than 30% of the studies. PRP has been used as PRP-derived supernatant or non-activated PRP. Two ranges could be identified for platelet concentration, the first between 0.14 × 10⁶ and 0.80 × 10⁶ platelets/µL and the second between 1.086 × 10⁶ and 10 × 10⁶ platelets/µL. Several studies have pooled PRP with a pool size varying from four to nine donors. The optimal dose for the PRP or PRP supernatant is 10%. PRP or PRP-derived supernatants a have positive effect on MSC colony number and size, cell proliferation, cell differentiation and genetic stability. The use of leukocyte-depleted PRP has been demonstrated to be a feasible alternative to xenogeneic sera. However, there is a need to improve the description of the PRP preparation methodology as well as its composition. Several items are identified and reported to create guidelines for future research.

A Review of In Vivo and Clinical Studies Applying Scaffolds and Cell Sheet Technology for Periodontal Ligament Regeneration

Different approaches to develop engineered scaffolds for periodontal tissues regeneration have been proposed. In this review, innovations in stem cell technology and scaffolds engineering focused primarily on Periodontal Ligament (PDL) regeneration are discussed and analyzed based on results from pre-clinical in vivo studies and clinical trials. Most of those developments include the use of polymeric materials with different patterning and surface nanotopography and printing of complex and sophisticated multiphasic composite scaffolds with different compartments to accomodate for the different periodontal tissues' architecture. Despite the increased effort in producing these scaffolds and their undoubtable efficiency to guide and support tissue regeneration, appropriate source of cells is also needed to provide new tissue formation and various biological and mechanochemical cues from the Extraccellular Matrix (ECM) to provide biophysical stimuli for cell growth and differentiation. Cell sheet engineering is a novel promising technique that allows obtaining cells in a sheet format while preserving ECM components. The right combination of those factors has not been discovered yet and efforts are still needed to ameliorate regenerative outcomes towards the functional organisation of the developed tissues.

The Evolution of Surgical Techniques and Biomaterials for Periodontal Regeneration

The understanding of biological concepts in wound healing together with the evolution in biomaterials applied in periodontal regeneration allowed for improved, minimally invasive surgical techniques with a wider range of application and adapted to achieve multiple goals at the same time. Regenerating attachment was never the sole end point, but maintaining the patient's own natural dentition in health and esthetics is becoming a feasible goal even in cases considered challenging just a few years ago. In this article we report on the evolution of techniques and biomaterials and their application in esthetic and challenging cases.

Role of Inhibitor SMADs in Stage 3 Grade B periodontitis before and after periodontal treatment

OBJECTIVE

This study aimed to examine the levels of transforming growth factor-beta (TGF-β) and inhibitory-Smads (I-Smads) in saliva and gingival crevicular fluid (GCF) in patients with Stage 3 Grade B periodontitis before and after non-surgical periodontal treatment.

BACKGROUND

Recently, it has been stated that Smads play an active role in all conditions where TGF-β is involved, including periodontal inflammation.

METHODS

Twenty healthy participants (control) and 20 patients with Stage 3, Grade B periodontitis were recruited. GCF and saliva samples and clinical periodontal recordings were investigated at the baseline and 1 month after treatment. TGF-β and I-Smads (Smads 6 and 7) were determined by ELISA.

RESULTS

Salivary Smad6 and Smad7 levels were significantly lower in the periodontitis group than healthy controls (p < .05), while there was no difference in salivary TGF-β levels between groups at baseline (p > .05). The total amounts and concentrations of GCF TGF-β, Smad6, and Smad7 were significantly lower in the periodontitis group than healthy controls at baseline (p < .05), and then decreased in concentration levels with treatment (p < .001). Positive correlations were found between total amounts and concentrations of GCF TGF-β, Smad6, and Smad7 (p < .05).

CONCLUSION

Our findings revealed that Smad6 and Smad7 in GCF and saliva decreased in periodontitis and then increased after periodontal treatment. Our study suggests that I-Smads act in parallel with TGF-β in periodontal inflammation and may have a role in the development of periodontitis.

PRP and PRF-Subgroups and Divisions When Used in Dentistry

Blood derivates, such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF), are autogenous sources of many growth factors that are involved in the healing and regeneration of tissues, and for this reason, are used in dentistry treatments. This fact also contributes to the growing interest in these biomaterials in regenerative personalized medicine. The multitude of platelet-rich forms creates many possibilities for their use. This semi-systematic review describes and compares the methods of obtaining properties and potential uses of these materials in personalized treatments.

Regeneration of rat periodontium by cementum protein 1-derived peptide

BACKGROUND AND OBJECTIVE

Cementum protein 1 (CEMP1) has the capacity to promote differentiation of periodontal ligament (PDL) cells toward a cementoblastic phenotype in vitro and bone regeneration in vivo. In this study, we tested the capabilities of a synthetic cementum protein 1-derived peptide, MGTSSTDSQQAGHRRCSTSN (CEMP1-p1), to promote regeneration of periodontal structures in a periodontal fenestration defect in rats.

MATERIAL AND METHODS

Fenestration defects were created using an extra-oral approach in the buccal aspect of the mandibular first molar roots. Eighteen male Wistar rats were divided into three groups. Two controls (defects non-treated or defects treated with a gelatin matrix scaffold [GMS] only) and the experimental group treated with 5 µg/dose of CEMP1-p1 embedded in GMS. After 28 days, the animals were sacrificed, and the mandibles processed for histopathological examination. Expression of cementum proteins, cementum attachment protein (CAP), CEMP1, integrin binding sialoprotein (IBSP), and osteocalcin (OCN), was assessed using immunofluorescence. The formation of new cementum, bone, and PDL fibers were compared between control and experimental groups.

RESULTS

The histological analysis revealed that the control group without any treatment new cementum or oriented PDL fibers were not observed. However, the presence of newly bone was detected. In the control group treated with GMS, new cementum formation was not detectable, the PDL fibers were oriented parallel to the longitudinal root axis, and new bone formation was observed. The experimental group showed deposit of acellular extrinsic fiber cementum (AEFC) in a lamellae-like feature with inserted Sharpey's fibers, formation of cellular mixed stratified cementum (CMSC) with the presence of cementocytes, and newly formed bone close to the cementum-enamel junction. Cementoblast cells adjacent to new cementum expressed CAP, CEMP1, IBSP, and OCN.

CONCLUSION

These studies show that CEMP1-p1 promotes the formation of AEFC, CMSC, new PDL with Sharpey's fibers inserted in cementum and bone, thus providing strong evidence that the synthetic peptide CEMP1-p1 promotes periodontal regeneration in a rat fenestration model.

Functions of beta2-adrenergic receptor in human periodontal ligament cells

Adrenergic receptors (ARs) are receptors of noradrenalin and adrenalin, of which there are nine different subtypes. In particular, β2 adrenergic receptor (β2-AR) is known to be related to the restoration and maintenance of homeostasis in bone and cardiac tissues; however, the functional role of signaling through β2-AR in periodontal ligament (PDL) tissue has not been fully examined. In this report, we investigated that β2-AR expression in PDL tissues and their features in PDL cells. β2-AR expressed in rat PDL tissues and human PDL cells (HPDLCs) derived from two different patients (HPDLCs-2G and -3S). Rat PDL tissue with occlusal loading showed high β2-AR expression, while its expression was downregulated in that without loading. In HPDLCs, β2-AR expression was increased exposed to stretch loading. The gene expression of PDL-related molecules was investigated in PDL clone cells (2-23 cells) overexpressing β2-AR. Their gene expression and intracellular cyclic adenosine monophosphate (cAMP) levels were also investigated in HPDLCs treated with a specific β2-AR agonist, fenoterol (FEN). Overexpression of β2-AR significantly promoted the gene expression of PDL-related molecules in 2 to 23 cells. FEN led to an upregulation in the expression of PDL-related molecules and increased intracellular cAMP levels in HPDLCs. In both HPDLCs, inhibition of cAMP signaling by using protein kinase A inhibitor suppressed the FEN-induced gene expression of α-smooth muscle actin. Our findings suggest that the occlusal force is important for β2-AR expression in PDL tissue and β2-AR is involved in fibroblastic differentiation and collagen synthesis of PDL cells. The signaling through β2-AR might be important for restoration and homeostasis of PDL tissue.

RhPDGF – Basic Characteristics and Potential Application in the Oral Surgery – An Overview

Growth factors (GFs) are bioactive molecules participating in organ development, tissue regeneration and repair. They are protein molecules with a relatively low molecular weight and are released by activated platelets. Platelet-derived growth factor (PDGF) is one of the GFs of highest amount in human platelets. It is known to stimulate cell proliferation and extracellular matrix synthesis, as well as angiogenesis in healthy tissues and neoplasms. However, most of the studies in the literature demonstrate the influence of PDGF on tissue regeneration without revealing its intimate mechanisms of action on different cell types. In the current review we emphasis on the effects of PDGF in order to stimulate various biological processes in wide number of pre-clinical and clinical studies.

Expression of gingival crevicular fluid markers during early and late healing of intrabony defects after surgical treatment: a systematic review

BACKGROUND

Surgical treatments such as guided tissue regeneration (GTR) and access flap surgery are widely employed for the treatment of intrabony defects. However, little is known regarding the postoperative expression of gingival crevicular fluid (GCF) markers.

OBJECTIVE

The aim of this systematic review was to compare the expression of GCF markers following treatment of periodontal intrabony defects with guided tissue regeneration or access surgery. The association of the markers' expression with the clinical outcome was also assessed.

METHODS

An electronic literature search was conducted in MEDLINE, EMBASE, OpenGrey, LILACS and Cochrane Library up to December 2018 complemented by a manual search. Human, prospective clinical studies were identified. The changes from baseline up to 30 days (early healing) and 3 months (late healing) were assessed.

RESULTS

A total of 164 publications were identified and reviewed for eligibility. Of these, 10 publications fulfilled the inclusion criteria. The included studies evaluated 15 different GCF markers with a follow-up time between 21 and 360 days postoperatively. PDGF, VEGF and TIMP-1 changes were often investigated in the included studies; however, contrasting results were reported. Two studies agreed that both GTR and OFD lead to similar OPG level changes. TGF-β1 is increased early postoperatively, irrespective of the surgical technique employed.

CONCLUSION

There is limited evidence available on the expression of GCF markers after surgical interventions of intrabony periodontal defects. However, OPG and TGF-β1 tend to increase early post-operatively, irrespective of the surgical technique employed, irrespective of the surgical technique employed.

CLINICAL RELEVANCE

More well-designed, powered studies with sampling periods reflecting the regenerative process are needed, and future research should focus on employing standardised protocols for collecting, storing and analysing GCF markers.

Biologics-based regenerative technologies for periodontal soft tissue engineering

This manuscript provides a state-of-the-art review on the efficacy of biologics in root coverage procedures, including enamel matrix derivative, platelet-derived growth factor, platelet concentrates, and fibroblast-growth factor-2. The mechanism of action and the rationale for using biologics in periodontal plastic surgery, as well as their anticipated benefits when compared with conventional approaches are discussed. Although the clinical significance is still under investigation, preclinical data and histologic evidence demonstrate that biologic-based techniques are able to promote periodontal regeneration coupled with the provision of tooth root coverage.

Autologous Platelet-Rich Plasma (CuteCell PRP) Safely Boosts In Vitro Human Fibroblast Expansion

Nowadays autologous fibroblast application for skin repair presents an important clinical interest. In most cases, in vitro skin cell culture is mandatory. However, cell expansion using xenogeneic or allogenic culture media presents some disadvantages, such as the risk of infection transmission or slow cell expansion. In this study, we investigated an autologous culture system to expand human skin fibroblast cells in vitro with the patient's own platelet-rich plasma (PRP). Human dermal fibroblasts were isolated from patients undergoing abdominoplasty, and blood was collected to prepare nonactivated PRP using the CuteCell™ PRP medical device. Cultures were followed up to 7 days using a medium supplemented with either fetal bovine serum (FBS) or PRP. Fibroblasts cultured in medium supplemented with PRP showed dose-dependently significantly higher proliferation rates (up to 7.7 times with 20% of PRP) and initiated a faster migration in the in vitro wound healing assay compared with FBS, while chromosomal stability was maintained. At high concentrations, PRP changed fibroblast morphology, inducing cytoskeleton rearrangement and an increase of alpha-smooth muscle actin and vimentin expression. Our findings show that autologous PRP is an efficient and cost-effective supplement for fibroblast culture, and should be considered as a safe alternative to xenogeneic/allogenic blood derivatives for in vitro cell expansion. Impact Statement Autologous dermal fibroblast graft is an important therapy in skin defect repair, but in vitro skin cell culture is mandatory in most cases. However, cell expansion using xenogeneic/allogenic culture media presents some disadvantages, such as the risk of infection transmission. We demonstrated that an autologous culture system with the patient's own platelet-rich plasma is an efficient, cost-effective, and safe supplement for fibroblast culture. As it respects the good manufacturing practices and regulatory agencies standards, it should be considered as a potent alternative and substitute to xenogeneic or allogenic blood derivatives for the validation of future clinical protocols using in vitro cell expansion.

Potential of growth factor incorporated mesoporous bioactive glass for in vivo bone regeneration

Mesoporous bioactive glass (MBG) has drawn much attention due to its superior surface texture, porosity and bioactive characteristics. Aim of the present study is to synthesize MBG using different surfactants, viz., hexadecyltrimethylamonium(CTAB) (M1), poly-ethylene glycol (PEG) (M2) and pluronic P123 (M3); bioactivity study; and to understand their bone regeneration efficacy in combination with insulin-like growth factors (IGF-1) in animal bone defect model. SBF study revealed the formation of calcium carbonate (CaCO₃) and hydroxyapatite (HAp) phase over 14 days. Formation of apatite layer was further confirmed by FTIR, FESEM and EDX analysis. M1 and M2 showed improved crystallinity, while M3 showed slightly decrease in crystalline peak of CaCO₃ and enhanced HAp phase. More Ca-P layer formed in M1 and M2 supported the in vivo experiments subsequently. Degree of new bone formation for all MBGs were high, i.e., M1 (80.7 ± 2.9%), M2 (74.4 ± 2.4%) and M3 (70.1 ± 1.9%) compared to BG (66.9 ± 1.8%). In vivo results indicated that the materials were non-toxic, biodegradable, biocompatible, and is suitable as bone replacement materials. Thus, we concluded that growth factor loaded MBG is a promising candidate for bone tissue engineering application.

Platelet-rich plasma stimulated proliferation, migration, and attachment of cultured periodontal ligament cells

Objective:

The aim of this study is to evaluate the effects of platelet-rich plasma (PRP) on the proliferation, migration, and attachment of cultured periodontal ligament (PDL) cells.

Materials and Methods:

3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assess number of PDL cells cultured in medium with or without PRP. Cell migration toward medium with or without PRP was assessed using the Boyden chamber. Cell attachment was assessed by counting cells on PRP or non-PRP coated dentin specimens. Group differences were analyzed using two-way ANOVA at 0.05 significance level.

Results:

In the MTT and cell migration assay, the number of cells in 5% and 10% PRP-treated groups were significantly higher than that in the non-PRP-treated group (P < 0.05). In the attachment assay, the number of cells on the dentin specimens in 10% PRP-treated group was significantly higher than that in the non-PRP treated group (P < 0.05).

Conclusion:

PRP could stimulate proliferation, migration, and attachment of PDL cells.

Programmed biomolecule delivery to enable and direct cell migration for connective tissue repair

Dense connective tissue injuries have limited repair, due to the paucity of cells at the wound site. We hypothesize that decreasing the density of the local extracellular matrix (ECM) in conjunction with releasing chemoattractive signals increases cellularity and tissue formation after injury. Using the knee meniscus as a model system, we query interstitial cell migration in the context of migratory barriers using a novel tissue Boyden chamber and show that a gradient of platelet-derived growth factor-AB (PDGF-AB) expedites migration through native tissue. To implement these signals in situ, we develop nanofibrous scaffolds with distinct fiber fractions that sequentially release active collagenase (to increase ECM porosity) and PDGF-AB (to attract endogenous cells) in a localized and coordinated manner. We show that, when placed into a meniscal defect, the controlled release of collagenase and PDGF-AB increases cellularity at the interface and within the scaffold, as well as integration with the surrounding tissue.

The potential of stromal cell-derived factor-1 delivery using a collagen membrane for bone regeneration

Stromal cell-derived factor-1 (SDF-1) is a cytokine that is important in stem and progenitor cell recruitment in tissue repair after injury. Regenerative procedures using collagen membranes (CMs) are presently well established in periodontal and implant dentistry. The objective of this study is to test the subsequent effects of the released SDF-1 from a CM on bone regeneration compared to platelet-derived growth factor (PDGF) in vitro and in vivo. For in vitro studies, cell proliferation, alkaline phosphatase activity, and osteoblastic differentiation marker genes were assessed after MC3T3-E1 mouse preosteoblasts were cultured with CMs containing factors. In vivo effects were investigated by placement of CMs containing SDF-1 or PDGF using a rat mandibular bone defect model. At 4 weeks after the surgery, the new bone formation was measured using micro-computed tomography (µCT) and histological analysis. The results of in vitro studies revealed that CM delivery of SDF-1 significantly induced cell proliferation, ALP activity, and gene expression of all osteogenic markers compared to the CM alone or control, similar to PDGF. Quantitative and qualitative µCT analysis for volume of new bone formation and the percentage of new bone area showed that SDF-1-treated groups significantly increased and accelerated bone regeneration compared to control and CM alone. The enhancement of bone formation in SDF-1-treated animals was dose-dependent and with levels similar to those measured with PDGF. These results suggest that a CM with SDF-1 may be a great candidate for growth factor delivery that could be a substitute for PDGF in clinical procedures where bone regeneration is necessary.

Mediating bone regeneration by means of drug eluting implants: From passive to smart strategies

In addition to excellent biocompatibility and mechanical performance, the new generation of bone and craniofacial implants are expected to proactively contribute to the regeneration process and dynamically interact with the host tissue. To this end, integration and sustained delivery of therapeutic agents has become a rapidly expanding area. The incorporated active molecules can offer supplementary features including promoting oteoconduction and angiogenesis, impeding bacterial infection and modulating host body reaction. Major limitations of the current practices consist of low drug stability overtime, poor control of release profile and kinetics as well as complexity of finding clinically appropriate drug dosage. In consideration of the multifaceted cascade of bone regeneration process, this research is moving towards dual/multiple drug delivery, where precise control on simultaneous or sequential delivery, considering the possible synergetic interaction of the incorporated bioactive factors is of utmost importance. Herein, recent advancements in fabrication of synthetic load bearing implants equipped with various drug delivery systems are reviewed. Smart drug delivery solutions, newly developed to provide higher tempo-spatial control on the delivery of the pharmaceutical agents for targeted and stimuli responsive delivery are highlighted. The future trend of implants with bone drug delivery mechanisms and the most common challenges hindering commercialization and the bench to bedside progress of the developed technologies are covered.

The Influence of Platelet-Derived Growth Factor and Bone Morphogenetic Protein Presentation on Tubule Organization by Human Umbilical Vascular Endothelial Cells and Human Mesenchymal Stem Cells in Coculture

A three-dimensional in vitro Matrigel plug was used as a model to explore delivery patterns of platelet-derived growth factor (PDGF) and bone morphogenetic protein-2 (BMP-2) to a coculture of human mesenchymal and endothelial cells. While BMP-2 is well recognized for its role in promoting fracture healing through proliferation and differentiation of osteoclast precursors, it is not a growth factor known to promote the process of angiogenesis, which is also critical for complete bone tissue repair. PDGF, in contrast, is a known regulator of angiogenesis, and also a powerful chemoattractant for osteoblast precursor cells. It has been suggested that presentation of PDGF followed by BMP may better promote vascularized bone tissue formation. Yet, it is unclear as to how cells would respond to various durations of delivery of each growth factor as well as to various amounts of overlap in presentation in terms of angiogenesis. Using a three-dimensional in vitro Matrigel plug model, we observed how various presentation schedules of PDGF and BMP-2 influenced tubule formation by human mesenchymal stem cells and human umbilical vascular endothelial cells. We observed that sequential presentation of PDGF to BMP-2 led to increased tubule formation over simultaneous delivery of these growth factors. Importantly, a 2-4 day overlap in the sequential presentation of PDGF and BMP-2 increased tubule formation as compared with groups with zero or complete growth factor overlap, suggesting that a moderate amount of angiogenic and osteogenic growth factor overlap may be beneficial for processes associated with angiogenesis.

Clinical Evaluation of Insulin like Growth Factor-I and Vascular Endothelial Growth Factor with Alloplastic Bone Graft Material in the Management of Human Two Wall Intra-Osseous Defects

INTRODUCTION

In recent years, emphasis on the use of growth factors for periodontal healing is gaining great momentum. Several growth factors showed promising results in periodontal regeneration.

AIM

This study was designed to compare the clinical outcomes of 0.8μg recombinant human Vascular Endothelial Growth Factor (rh-VEGF) and 10μg recombinant human Insulin Like Growth Factor-I (rh-IGF-I) with β-Tricalcium Phosphate (β-TCP) and Polylactide-Polyglycolide Acid (PLGA) membrane in two wall intra-osseous defects.

MATERIALS AND METHODS

A total of 29 intra-osseous defects in 27 subjects were randomly divided into 3 test and 1 control group. Test group I (n=8) received rh-VEGF+ rh-IGF-I, Test group II (n=7) rh-VEGF, Test group III (n=7) rh-IGF-I and control group (n=7) with no growth factor, β-TCP and PLGA membrane was used in all the groups. Baseline soft tissue parameters including Probing Pocket Depth (PPD), Clinical Attachment Level (CAL), and Gingival Recession (GR) at selected sites were recorded at baseline and at 6 months. Intrasurgically, intra-osseous component was calculated as a) Cemento-Enamel Junction to Bone Crest (CEJ to BC), b) Bone Crest to Base of the Defect (BC to BD) at baseline and at re-entry. The mean changes at baseline and after 6 months within each group were compared using Wilcoxon Signed Rank Test. The mean changes for each parameter between groups were compared using Mann-Whitney U test.

RESULTS

After 6 months, maximum mean PPD reduction occurred in test group I followed by test group II, III and control group. Similar trend was observed in CAL gain. Non-significant GR was present in test group I and control group whereas in test group II and III GR was absent. The use of rh-VEGF+ rhIGF-I exhibited 95.8% osseous fill as compared to 54.8% in test group II, 52.7% in test group III and 41.1 % in the control group.

CONCLUSION

Within the limitations of this study, it can be concluded that, rh-IGF-I+rh-VEGF treated sites resulted in greater improvement in PPD reduction, CAL gain as well as in osseous fill after 6 months when compared with rh-VEGF, rh-IGF-I and control sites.

Autologous blood preparations rich in platelets, fibrin and growth factors

OBJECTIVES

Bone regeneration is often needed prior to dental implant treatment due to the lack of adequate quantity and quality after infectious diseases. The greatest regenerative power was obtained with autologous tissue, primarily the bone alive, taken from the same site or adjacent sites, up to the use centrifugation of blood with the selection of the parts with the greatest potential regenerative. In fact, various techniques and technologies were chronologically successive to cope with an ever better preparation of these concentrates of blood. Our aim is to review these advances and discuss the ways in which platelet concentrates may provide such unexpected beneficial therapeutic effects.

METHODS

The research has been carried out in the MEDLINE and Cochrane Central Register of Controlled Trials database by choosing keywords as "platelet rich plasma", "platelet rich fibrin", "platelet growth factors", and "bone regeneration" and "dentistry".

RESULTS

Autologous platelet rich plasma is a safe and low cost procedure to deliver growth factors for bone and soft tissue healing.

CONCLUSION

The great heterogeneity of clinical outcomes can be explained by the different PRP products with qualitative and quantitative difference among substance.

IGF-loaded silicon and zinc doped brushite cement: physico-mechanical characterization and in vivo osteogenesis evaluation

Dopants play critical roles in controlling the physical, mechanical, degradation kinetics, and in vivo properties of calcium phosphates. The aim of the present study was to evaluate the effects of silicon (Si) and zinc (Zn) dopants on the physico-mechanical and in vivo osteogenesis properties of brushite cements (BrCs) alone and in combination with insulin like growth factor 1 (IGF-1). Addition of 0.5 wt% Si did not alter the setting time, β-TCP content, and compressive strength of BrCs significantly; however, 0.25 wt% Zn incorporation was accompanied by a significant decrease in mechanical strength from 4.78 ± 0.21 MPa for pure BrC to 3.78 ± 0.59 MPa and 3.28 ± 0.22 MPa for Zn-BrC and Si/Zn-BrC, respectively. The in vivo bone regeneration properties of doped BrCs alone and in combination with IGF-1 were assessed and compared using chronological radiography, histology, scanning electron microscopy and fluorochrome labeling at 2 and 4 months post implantation in a rabbit femoral defect model. Based on in vivo characterization focusing on osteogenesis and vasculogenesis, Si-BrC and Si/Zn-BrC showed the best performance followed by Zn-BrC and pure BrCs. Addition of IGF-1 further improved bone regeneration. Our findings confirm that addition of Si and/or Zn alters the physico-mechanical properties of BrCs and promotes the early stage in vivo osseointegration and bone remodeling properties.

Enamel matrix proteins exhibit growth factor activity: A review of evidence at the cellular and molecular levels

Enamel matrix derivative (EMD) is a commercially available protein extract, mainly comprising amelogenins. A number of other polypeptides have been identified in EMD, mostly growth factors, which promote cementogenesis and osteogenesis during the regeneration processes through the regulation of cell proliferation, differentiation and activity; however, not all of their functions are clear. Enamel extracts have been proposed to have numerous activities such as bone morphogenetic protein- and transforming growth factor β (TGF-β)-like activity, and activities similar to those of insulin-like growth factor, fibroblast growth factor, platelet-derived growth factor, vascular endothelial growth factor and epidermal growth factor. These activities have been observed at the molecular and cellular levels and in numerous animal models. Furthermore, it has been suggested that EMD contains an unidentified biologically active factor that acts in combination with TGF-β1, and several studies have reported functional similarities between growth factors and TGF-β in cellular processes. The effects of enamel extracts on the cell cycle and biology are summarized and discussed in this review.

Agent-based computational model investigates muscle-specific responses to disuse-induced atrophy

Skeletal muscle is highly responsive to use. In particular, muscle atrophy attributable to decreased activity is a common problem among the elderly and injured/immobile. However, each muscle does not respond the same way. We developed an agent-based model that generates a tissue-level skeletal muscle response to disuse/immobilization. The model incorporates tissue-specific muscle fiber architecture parameters and simulates changes in muscle fiber size as a result of disuse-induced atrophy that are consistent with published experiments. We created simulations of 49 forelimb and hindlimb muscles of the rat by incorporating eight fiber-type and size parameters to explore how these parameters, which vary widely across muscles, influence sensitivity to disuse-induced atrophy. Of the 49 muscles modeled, the soleus exhibited the greatest atrophy after 14 days of simulated immobilization (51% decrease in fiber size), whereas the extensor digitorum communis atrophied the least (32%). Analysis of these simulations revealed that both fiber-type distribution and fiber-size distribution influence the sensitivity to disuse atrophy even though no single tissue architecture parameter correlated with atrophy rate. Additionally, software agents representing fibroblasts were incorporated into the model to investigate cellular interactions during atrophy. Sensitivity analyses revealed that fibroblast agents have the potential to affect disuse-induced atrophy, albeit with a lesser effect than fiber type and size. In particular, muscle atrophy elevated slightly with increased initial fibroblast population and increased production of TNF-α. Overall, the agent-based model provides a novel framework for investigating both tissue adaptations and cellular interactions in skeletal muscle during atrophy.

Strategies to direct the enrichment, expansion, and recruitment of regulatory cells for the treatment of disease

Disease and injury perturb the balance of processes associated with inflammation and tissue remodeling, resulting in positive feedback loops, exacerbation of disease and compromised tissue repair. Conversely, under homeostatic healthy conditions, these processes are tightly regulated through the expansion and/or recruitment of specific cell populations, promoting a balanced steady-state. Better understanding of these regulatory processes and recent advances in biomaterials and biotechnology have prompted strategies to utilize cells for the treatment and prevention of disease through regulation of inflammation and promotion of tissue repair. Herein, we describe how cells that regulate these processes can be increased in prevalence at a site of disease or injury. We review several relevant cell therapy approaches as well as new strategies for directing endogenous regulatory cells capable of promoting environmental homeostasis and even the establishment of a pro-regenerative micro-environment. Collectively, these examples may provide a blueprint for next-generation "medicine" that spurs the body's own cells to action and replaces conventional drugs.

Autologous Platelet Gel

Leg ulcers represent a particularly disabling complication in patients with sickle cell disease (SCD). Platelet gel (PG) is a novel therapeutic strategy used for accelerating wound healing of a wide range of tissues through the continuous release of platelet growth factors. Here, we describe the use of PG preparation according to Anitua’s PRGF (preparations rich in growth factors) protocol for treating chronic nonhealing ulcers in patients with SCD. A positive response occurred in 3 patients with an area reduction of 85.7% to 100%, which occurred within 7 to 10 weeks, and a 35.2% and 20.5% of area reduction in 2 other patients, who however, had large ulcers. After calcium chloride addition, the platelet-rich plasmas demonstrated enhanced platelet-derived growth factors–BB ( P < .001), transforming growth factor-β1 ( P = .015), vascular endothelial growth factors ( P = .03), and hepatocyte growth factors (nonsignificant) secretion. Furthermore, calcium chloride addition induced a significant decrease in platelet number ( P = .0134) and there was no leukocyte detection in the PG product. These results demonstrate that PG treatment might impact the healing of leg ulcers in sickle cell disease, especially in patients with small ulcers.

Effects of orthodontic load on the periodontium of autogenously transplanted teeth in beagle dogs

OBJECTIVE

To observe the periodontal healing of autogenously transplanted teeth loaded orthodontically after autotransplantation in Beagle dogs.

METHODS

Forty-eight teeth were autogenously transplanted, 24 of which were loaded postoperatively with orthodontic force at different time points and for different durations. Periodontal healing was evaluated by probing pocket depth (PPD), the expression of relevant proteins, and histomorphometric analyses.

RESULTS

The dental pockets of loaded and non-loaded teeth were both much deeper after the first postoperative week than before transplantation (P<0.05). Later, the PPD, which was measured after postoperative weeks 1, 3, 5, 9 and 13, gradually became shallow. The expressions of alkaline phosphatase (ALP) and basic fibroblast growth factor (bFGF) were higher in loaded teeth than in non-loaded teeth (P<0.05), and in groups subjected to two weeks duration of loading than in other groups at the same load time point (P<0.05). For the same load duration, the expressions of ALP and bFGF in teeth loaded after postoperative week 4 were higher than those of other treatments (P<0.05). According to histomorphometric analyses, an orthodontic force on transplanted teeth applied after postoperative weeks 4 or 8 for two weeks duration should be favorable for periodontal healing.

CONCLUSIONS

It is advisable to apply an appropriate magnitude of force on autotransplanted teeth, such as orthodontic force, at appropriate time points and for a suitable duration, to achieve the optimal clinical prognosis following autogenous tooth transplantation. These results may serve as a basis for subsequent studies in humans so as to make clinical improvements.

Differential effects of growth factors and cytokines on the synthesis of SPARC, DNA, fibronectin and alkaline phosphatase activity in human periodontal ligament cells

Growth factors and cytokines play an important role in tissue development and repair. However, it remains unknown how they act on proliferation and differentiation of periodontal ligament cells. In this study, we investigated the effects of several growth factors and cytokines on the synthesis of DNA, alkaline phosphatase (ALPase), fibronectin, and secreted protein acidic and rich in cysteine (SPARC) in human periodontal ligament (HPL) cells. Transforming growth factor-beta (TGF-beta) increased the synthesis of DNA, fibronectin and SPARC, whereas it decreased ALPase activity. Basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF) and tumor necrosis factor-alpha (TNF-alpha) decreased SPARC and ALPase levels, whereas these peptides increased DNA synthesis and did not affect fibronectin synthesis. Epidermal growth factor (EGF) up-regulated the synthesis of DNA and fibronectin and inhibited SPARC and ALPase levels. Interleukin-1beta (IL-1beta) decreased the synthesis of DNA, ALPase, fibronectin and SPARC. These findings demonstrate that TGF-beta, bFGF, EGF, PDGF, TNF-alpha and IL-1beta have characteristically different patterns of action on DNA, SPARC, fibronectin and ALPase synthesis by HPL cells. The differences in regulation of function of periodontal ligament cells by these peptides may be involved in the regeneration and repair of periodontal tissue.

Prospective potency of TGF-β1 on maintenance and regeneration of periodontal tissue

Periodontal ligament (PDL) tissue, central in the periodontium, plays crucial roles in sustaining tooth in the bone socket. Irreparable damages of this tissue provoke tooth loss, causing a decreased quality of life. The question arises as to how PDL tissue is maintained or how the lost PDL tissue can be regenerated. Stem cells included in PDL tissue (PDLSCs) are widely accepted to have the potential to maintain or regenerate the periodontium, but PDLSCs are very few in number. In recent studies, undifferentiated clonal human PDL cell lines were developed to elucidate the applicable potentials of PDLSCs for the periodontal regenerative medicine based on cell-based tissue engineering. In addition, it has been suggested that transforming growth factor-beta 1 is an eligible factor for the maintenance and regeneration of PDL tissue.

Protein growth factors loaded highly porous chitosan scaffold: a comparison of bone healing properties

Present study aimed to investigate and compare effectiveness of porous chitosan alone and in combination with insulin like growth factor-1 (IGF-1) and bone morphogenetic protein-2 (BMP-2) in bone healing. Highly porous (85±2%) with wide distribution of macroporous (70-900 μm) chitosan scaffolds were fabricated as bone substitutes by employing a simple liquid hardening method using 2% (w/v) chitosan suspension. IGF-1 and BMP-2 were infiltrated using vacuum infiltration with freeze drying method. Adsorption efficiency was found to be 87±2 and 90±2% for BMP-2 and IGF-1 respectively. After thorough material characterization (pore details, FTIR and SEM), samples were used for subsequent in vivo animal trial. Eighteen rabbit models were used to evaluate and compare control (chitosan) (group A), chitosan with IGF-1 (group B) and chitosan with BMP-2 (group C) in the repair of critical size bone defect in tibia. Radiologically, there was evidence of radiodensity in defect area from 60th day (initiated on 30th day) in groups B and C as compared to group A and attaining nearly bony density in most of the part at day 90. Histological results depicted well developed osteoblastic proliferation around haversian canal along with proliferating fibroblast, vascularization and reticular network which was more pronounced in group B followed by groups C and A. Fluorochrome labeling and SEM studies in all groups showed similar outcome. Hence, porous chitosan alone and in combination with growth factors (GFs) can be successfully used for bone defect healing with slight advantage of IGF-1 in chitosan samples.

Inactivation of epidermal growth factor by Porphyromonas gingivalis as a potential mechanism for periodontal tissue damage

Porphyromonas gingivalis is a Gram-negative bacterium associated with the development of periodontitis. The evolutionary success of this pathogen results directly from the presence of numerous virulence factors, including peptidylarginine deiminase (PPAD), an enzyme that converts arginine to citrulline in proteins and peptides. Such posttranslational modification is thought to affect the function of many different signaling molecules. Taking into account the importance of tissue remodeling and repair mechanisms for periodontal homeostasis, which are orchestrated by ligands of the epidermal growth factor receptor (EGFR), we investigated the ability of PPAD to distort cross talk between the epithelium and the epidermal growth factor (EGF) signaling pathway. We found that EGF preincubation with purified recombinant PPAD, or a wild-type strain of P. gingivalis, but not with a PPAD-deficient isogenic mutant, efficiently hindered the ability of the growth factor to stimulate epidermal cell proliferation and migration. In addition, PPAD abrogated EGFR-EGF interaction-dependent stimulation of expression of suppressor of cytokine signaling 3 and interferon regulatory factor 1. Biochemical analysis clearly showed that the PPAD-exerted effects on EGF activities were solely due to deimination of the C-terminal arginine. Interestingly, citrullination of two internal Arg residues with human endogenous peptidylarginine deiminases did not alter EFG function, arguing that the C-terminal arginine is essential for EGF biological activity. Cumulatively, these data suggest that the PPAD-activity-abrogating EGF function in gingival pockets may at least partially contribute to tissue damage and delayed healing within P. gingivalis-infected periodontia.

The effect of platelet derived growth factor-AB on periodontal ligament fibroblasts: An in vitro study

Background and Objectives:

Traditional methods of periodontal therapy produce results in healing of tissues by repair; however, what we require is regeneration of the lost tissues. The periodontal ligament (PDL) cells appear to be important in periodontal wound healing. Platelet derived growth factor (PDGF), a potent mitogen and useful mediator for wound healing, has been extensively studied in periodontal regeneration. This in vitro study was designed to evaluate the effect of PDGF-AB on human PDL fibroblasts (hPDLF) at 50, 100 and 150 ng/ml dosages at 24, 48 and 72 hours time duration.

Materials and Methods:

Tissue explants from three different patients were harvested from the roots of freshly extracted, uninfected and impacted third molars. The cells cultured from all samples were divided into 4 groups: Group-1 was the control group, and the experimental groups were designated as Group-2, Group-3 and Group-4, to test the effect of PDGF-AB at 50, 100 and 150 ng/ml by proliferation assay carried out at 24, 48 and 72 hours.

Results:

The results revealed maximum mitogenic response of PDL cells at 100 ng/ml and at 48 hours, suggesting that the mitogenic response of PDGF-AB is both, time and dose dependent.

Conclusions:

The results of this in vitro study suggest that PDGF has maximum mitogenic response on hPDLF at 48 hours and for 100 ng dose. However for clinical application, randomized controlled clinical trials are required to substantiate the results of this in vitro study.

Advanced reconstructive technologies for periodontal tissue repair

Reconstructive therapies to promote the regeneration of lost periodontal support have been investigated through both preclinical and clinical studies. Advanced regenerative technologies using new barrier-membrane techniques, cell-growth-stimulating proteins or gene-delivery applications have entered the clinical arena. Wound-healing approaches using growth factors to target the restoration of tooth-supporting bone, periodontal ligament and cementum are shown to significantly advance the field of periodontal-regenerative medicine. Topical delivery of growth factors, such as platelet-derived growth factor, fibroblast growth factor or bone morphogenetic proteins, to periodontal wounds has demonstrated promising results. Future directions in the delivery of growth factors or other signaling models involve the development of innovative scaffolding matrices, cell therapy and gene transfer, and these issues are discussed in this paper.

Platelet-derived growth factor promotes periodontal regeneration in localized osseous defects: 36-month extension results from a randomized, controlled, double-masked clinical trial

BACKGROUND

Recombinant human platelet-derived growth factor (rhPDGF) is safe and effective for the treatment of periodontal defects in short-term studies up to 6 months in duration. We now provide results from a 36-month extension study of a multicenter, randomized, controlled clinical trial evaluating the effect and long-term stability of PDGF-BB treatment in patients with localized severe periodontal osseous defects.

METHODS

A total of 135 participants were enrolled from six clinical centers for an extension trial. Eighty-three individuals completed the study at 36 months and were included in the analysis. The study investigated the local application of β-tricalcium phosphate scaffold matrix with or without two different dose levels of PDGF (0.3 or 1.0 mg/mL PDGF-BB) in patients possessing one localized periodontal osseous defect. Composite analysis for clinical and radiographic evidence of treatment success was defined as percentage of cases with clinical attachment level (CAL) ≥2.7 mm and linear bone growth (LBG) ≥1.1 mm.

RESULTS

The participants exceeding this composite outcome benchmark in the 0.3 mg/mL rhPDGF-BB group went from 62.2% at 12 months, 75.9% at 24 months, to 87.0% at 36 months compared with 39.5%, 48.3%, and 53.8%, respectively, in the scaffold control group at these same time points (P <0.05). Although there were no significant increases in CAL and LBG at 36 months among all groups, there were continued increases in CAL gain, LBG, and percentage bone fill over time, suggesting overall stability of the regenerative response.

CONCLUSION

PDGF-BB in a synthetic scaffold matrix promotes long-term stable clinical and radiographic improvements as measured by composite outcomes for CAL gain and LBG for patients possessing localized periodontal defects ( ClinicalTrials.gov no. CT01530126).

Low-level laser irradiation affects the release of basic fibroblast growth factor (bFGF), insulin-like growth factor-I (IGF-I), and receptor of IGF-I (IGFBP3) from osteoblasts

OBJECTIVE

It was the aim of the present study to evaluate whether the laser irradiation of osteoblasts could enhance the release of growth factors including basic fibroblast growth factor (bFGF), insulin-like growth factor-I (IGF-I), and receptor of IGF-I (IGFBP3).

BACKGROUND DATA

Low-level laser therapy (LLLT) has been shown to have biostimulatory effects on various cell types by enhancing production of some cytokines and growth factors.

MATERIALS AND METHODS

Human mesenchymal stem cells (MSCs) were seeded in osteogenic medium and differentiated into osteoblasts. Three groups were formed: in the first group (single dose group), osteoblasts were irradiated with laser (685 nm, 25 mW, 14.3 mW/cm(2), 140 sec, 2 J/cm(2)) for one time; and in the second group, energy at the same dose was applied for 2 consecutive days (double dose group). The third group was not irradiated with laser and served as the control group. Proliferation, viability, bFGF, IGF-I, and IGFBP3 levels were compared between groups.

RESULTS

Both of the irradiated groups revealed higher proliferation, viability, bFGF, IGF-I, and IGFBP3 expressions than did the nonirradiated control group. There was increase in bFGF and IGF-I expressions and decrease in IGFBP3 in the double dose group compared to single dose group.

CONCLUSIONS

The results of the present study indicate that LLLT increases the proliferation of osteoblast cells and stimulates the release of bFGF, IGF-I, and IGFBP3 from these cells. The biostimulatory effect of LLLT may be related to the enhanced production of the growth factors.

A comparative study of root defect coverage using an acellular dermal matrix with and without a recombinant human platelet-derived growth factor

BACKGROUND

The objective of this case series is to compare root defect coverage results and healing responses of bilateral recession defects treated with acellular dermal matrix (ADM) with and without recombinant human platelet-derived growth factor (rhPDGF).

METHODS

Seventeen patients with 40 bilateral gingival recession defects were compared. Each defect was ≥2 mm and treated with ADM and a coronally advanced flap. Using split-mouth design, the control-side ADM was hydrated in sterile saline, whereas the test-side ADM was hydrated in rhPDGF. The patients were evaluated at 1 week, 1 month, 3 months, and 6 months. Standardized measurements were taken preoperatively at 3 and 6 months. Healing was clinically assessed at 1 week and 1 month post-surgically.

RESULTS

Both test and control groups showed significant gain in root defect coverage over the 6-month period for all individuals, with the test group showing a 69.0% gain and the control group showing a 76.7% gain. Patients divided into Miller Class I and Class III defects were also found to have a significant gain in root defect coverage over 6 months. The test group showed 84.1% gain, and the control group showed 84.7% gain for Miller Class I defects. For Miller Class III defects, the test group showed 51.5% gain, and the control group showed a 60.8% gain. One week after surgery, 35% of the test group showed better healing, whereas 15% of the control group showed better healing. One month after surgery, 20% of the test group showed better healing, whereas 15% of the control group showed better healing.

CONCLUSION

Based on the results of this case series, there were no statistically or clinically significant differences in root defect coverage, keratinized tissue, clinical attachment level, or clinical healing for treatment of root recession with a coronally advanced flap and ADM with and without rhPDGF.

Growth Differentiation Factor 5 (GDF-5) Induces Matrix Metalloproteinase 2 (MMP-2) Expression in Periodontal Ligament Cells and Modulates MMP-2 and MMP-13 Activity in Osteoblasts

Growth differentiation factor 5 (GDF-5), a member of the transforming growth factor beta (TGF-β) superfamily expressed in periodontal tissues, promotes extracellular matrix (ECM) in periodontal ligament (PDL) cells. Matrix metalloproteinases (MMP) are proteolytic enzymes that degrade ECM and are expressed in PDL cells. To date, little is known about the regulation of MMP synthesis and secretion in PDL cells. The aim of this study is to examine the effects of GDF-5 on MMP production and activity in PDL cells. GDF-5 increased both collagen type I alpha 2 (Col Iα2) and MMP-2 gene expression in cells derived from mouse PDL tissues after 3 days of culture. Because PDL cells represent a heterogeneous population, we examined gelatinolytic activity and gene expression profiles in an osteoblast cell line. After 6, 12, 24, and 48 hours of culture, GDF-5 increased both Col Iα2 and MMP gene expression in osteoblasts. GDF-5 also promoted MMP-2 activity as revealed by gelatin zymography after 7 days of culture. In the presence of the p38 MAP kinase inhibitor SB202190, on the other hand, MMP-2 activity was blocked. Taken together, these results indicate that GDF-5 may increase simultaneously the gene expression of type I collagen and MMP-2 in the osteoblast-like cells among the PDL cells and p38 MAP kinase pathway in osteoblast could involve in the regulation of MMP-2 enzyme activity induced by GDF-5.