Preface to the 9th Biennial COAST Conference: Harnessing Technology and Biomedicine for Personalized Orthodontics

OBJECTIVE

The Consortium on Orthodontic Advances in Science and Technology (COAST) convened for its 9th biennial conference titled 'Harnessing Technology and Biomedicine for Personalized Orthodontics' to explore cutting-edge craniofacial research towards building the foundations for precision care in orthodontics.

SETTING AND SAMPLE POPULATION

Seventy-five faculty, scholars, private practitioners, industry, residents and students met at the UCLA Arrowhead Lodge on 6-9 November 2022 for networking, scientific presentations and facilitated discussions. Thirty-three speakers provided state-of-the-art, evidence-based scientific and perspective updates in craniofacial and orthodontic-related fields. The overall format included an Education Innovation Award Faculty Development Career Enrichment (FaCE) workshop focused on faculty career development, three lunch and learns, keynote or short talks and poster presentations.

MATERIAL AND METHODS

The 2022 COAST Conference was organized thematically to include (a) genes, cells and environment in craniofacial development and abnormalities; (b) precision modulation of tooth movement, retention and facial growth; (c) applications of artificial intelligence in craniofacial health; (d) precision approaches to Sleep Medicine, OSA and TMJ therapies; and (e) precision technologies and appliances.

RESULTS

The collective advances in orthodontics and science represented in the manuscripts of this issue fulfil our goal of laying solid foundations for personalized orthodontics. Participants elevated the need for stronger industry-academic research partnerships to leverage knowledge gained from large datasets with treatment approaches and outcomes; systematizing the potential of big data including through multi-omics and artificial intelligence approaches; refining the genotype: phenotype correlation to create biotechnology that will rescue inherited dental and craniofacial defects; evolving studies of tooth movement, sleep apnoea and TMD treatment to accurately measure dysfunction and treatment successes; and maximizing the integration of newer orthodontic devices and digital workflows.

CONCLUSIONS

Technological advances combined with those in biomedicine and machine learning are rapidly changing the delivery of health care including that in orthodontics. These advances promise to lead to enhanced customization, efficiencies and outcomes of patient care in routine orthodontic problems and in severe craniofacial problems, OSA and TMD.

Connecting the dots towards precision orthodontics

Precision orthodontics entails the use of personalized clinical, biological, social and environmental knowledge of each patient for deep individualized clinical phenotyping and diagnosis combined with the delivery of care using advanced customized devices, technologies and biologics. From its historical origins as a mechanotherapy and materials driven profession, the most recent advances in orthodontics in the past three decades have been propelled by technological innovations including volumetric and surface 3D imaging and printing, advances in software that facilitate the derivation of diagnostic details, enhanced personalization of treatment plans and fabrication of custom appliances. Still, the use of these diagnostic and therapeutic technologies is largely phenotype driven, focusing mainly on facial/skeletal morphology and tooth positions. Future advances in orthodontics will involve comprehensive understanding of an individual's biology through omics, a field of biology that involves large-scale rapid analyses of DNA, mRNA, proteins and other biological regulators from a cell, tissue or organism. Such understanding will define individual biological attributes that will impact diagnosis, treatment decisions, risk assessment and prognostics of therapy. Equally important are the advances in artificial intelligence (AI) and machine learning, and its applications in orthodontics. AI is already being used to perform validation of approaches for diagnostic purposes such as landmark identification, cephalometric tracings, diagnosis of pathologies and facial phenotyping from radiographs and/or photographs. Other areas for future discoveries and utilization of AI will include clinical decision support, precision orthodontics, payer decisions and risk prediction. The synergies between deep 3D phenotyping and advances in materials, omics and AI will propel the technological and omics era towards achieving the goal of delivering optimized and predictable precision orthodontics.

Unilateral loss of maxillary molars in young mice leads to bilateral condylar adaptation and degenerative disease

The adaptive response of the mandible and temporomandibular joint (TMJ) to altered occlusion in juvenile patients is presently unclear. To address this question, we established a mouse model in which all molars were extracted from the maxillary right quadrant in prepubertal, 3‐week‐old mice and analyzed morphological, tissue, cellular, and molecular changes in the mandible and condyle 3 weeks later. Unilateral loss of maxillary molars led to significant, robust, bilateral changes, primarily in condylar morphology, including anteroposterior narrowing of the condylar head and neck and increased convexity at the condylar surface, as determined by geometric morphometric analysis. Furthermore, both condyles in experimental mice exhibited a degenerative phenotype, which included decreased bone volume and increased mineral density near the condylar head surface compared to control mice. Changes in condylar morphology and mineralized tissue composition were associated with alterations in the cellular architecture of the mandibular condylar cartilage, including increased expression of markers for mature (Col2a1) and hypertrophic (Col10a1) chondrocytes, suggesting a shift toward differentiating chondrocytes. Our results show significant bilateral condylar morphological changes, alterations in tissue composition, cellular organization, and molecular expression, as well as degenerative disease, in response to the unilateral loss of teeth. Our study provides a relatively simple, tractable mouse tooth extraction system that will be of utility in uncovering the cellular and molecular mechanisms of condylar and mandibular adaptation in response to altered occlusion. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Using Twitter to promote #orthodontic research and clinical innovations: Practice and challenges

While Twitter has substantial benefits in real-time sharing and dissemination of information and facilitating discussions, currently there is a noticeable absence of its use in the orthodontic profession and peer-reviewed journals. This review aims to introduce the basics of using social media; provide a perspective and prospective vision on effective practices on the use of Twitter in sharing orthodontic discoveries and clinical innovations; and discuss the limitations and caveats of using such approaches in sharing and assimilating information. There has been increasing debate on the potential role of social media, specifically Twitter, in shaping the way scholars and clinicians access, discuss, and disseminate research and clinical innovations. Despite various caveats, such as misinformation, privacy concerns, and unprofessionalism, Twitter can be used to efficiently share discoveries and innovations and facilitate networking. Thus, the use of Twitter during professional orthodontic meetings can enhance their impact by enabling nonattendees to participate in the meeting virtually and in real time. Moreover, utilization of Twitter by peer-reviewed journals can aid in enhancing the dissemination of information. That, with the optimization of algorithms and strategies, can also maximize reach and impact. Future efforts are essential to develop standardized guidelines for the use of Twitter among orthodontic healthcare professionals and scholars to better manage scientific integrity, privacy, and ethical concerns. Professional orthodontic organizations, journals, and researchers should be aware of the potential benefits of Twitter strategies that could be applied to maximize the impact and dissemination of orthodontic discoveries to reach the largest possible audience that will facilitate collaboration and discussion, and advance the delivery of cutting-edge treatments.

The Significance of Utilizing A Corticotomy on Periodontal and Orthodontic Outcomes: A Systematic Review and Meta-Analysis

Simple Summary

The collaboration between periodontics and orthodontics has the potential to allow safer orthodontic tooth movement and improve vulnerable oral conditions especially for patients with very thin bone and soft tissue. By providing this interdisciplinary surgical approach where thin bone and soft tissue are surgically augmented to convert a fragile-thin to a robust-thick tissue phenotype, this permits orthodontic treatment in these previously thin tissue cases to proceed without iatrogenically induced adverse effects. This is an infrequently performed procedure with few clinical recommendations. This review paper provides the rationale and the currently available evidence on the benefits of this novel surgical approach.

Abstract

Purpose: This systematic review compares the clinical and radiographic outcomes for patients who received only a corticotomy or periodontal accelerated osteogenic orthodontics (PAOO) with those who received a conventional orthodontic treatment. Methods: An electronic search of four databases and a hand search of peer-reviewed journals for relevant articles published in English between January 1980 and June 2021 were performed. Human clinical trials of ≥10 patients treated with a corticotomy or PAOO with radiographic and/or clinical outcomes were included. Meta-analyses were performed to analyze the weighted mean difference (WMD) and confidence interval (CI) for the recorded variables. Results: Twelve articles were included in the quantitative analysis. The meta-analysis revealed a localized corticotomy distal to the canine can significantly increase canine distalization (WMD = 1.15 mm, 95% CI = 0.18–2.12 mm, p = 0.02) compared to a conventional orthodontic treatment. In addition, PAOO also showed a significant gain of buccal bone thickness (WMD = 0.43 mm, 95% CI = 0.09–0.78 mm, p = 0.01) and an improvement of bone density (WMD = 32.86, 95% CI = 11.83–53.89, p = 0.002) compared to the corticotomy group. Conclusion: Based on the findings of the meta-analyses, the localized use of a corticotomy can significantly increase the amount of canine distalization during orthodontic treatment. Additionally, the use of a corticotomy as a part of a PAOO procedure significantly increases the rate of orthodontic tooth movement and it is accompanied by an increased buccal bone thickness and bone density compared to patients undergoing a conventional orthodontic treatment.

IGF-1 TMJ injections enhance mandibular growth and bone quality in juvenile rats

OBJECTIVES

Dentofacial orthopaedic treatment of mandibular hypoplasia has unpredictable skeletal outcomes. Although several biomodulators including insulin-like growth factor 1 (IGF-1) are known to contribute to chondrocyte proliferation, their efficacy in modulating mandibular growth has not been validated. The aim of this study was to determine the effect of locally delivered IGF-1 on mandibular growth and condylar bone quality/quantity in juvenile rats.

SETTING AND SAMPLE POPULATION

Institutional vivarium using twenty-four 35-day-old male Sprague-Dawley rats.

METHODS

PBS or 40 µg/kg (low-dose) IGF-1 or 80 µg/kg (high-dose) IGF-1 was injected bilaterally into the temporomandibular joints of the rats at weekly intervals for four weeks. Cephalometric and micro-computed tomography measurements were used to determine mandibular dimensions. Bone and tissue mineral density, volume fraction and mineral content were determined, and serum IGF-1 concentrations assayed.

RESULTS

Intra-articular administration of high-dose IGF-1 contributed to a significant 6%-12% increase in mandibular body and condylar length compared to control and low-dose IGF-1-treated animals. Additionally, IGF-1 treatment resulted in a significant decrease in the angulation of the lower incisors to mandibular plane. Condylar bone volume, bone volume fraction, mineral content and mineral density were significantly increased with high-dose IGF-1 relative to control and low-dose IGF-1 groups. Serum IGF-1 levels were similar between all groups confirming limited systemic exposure to the locally administered IGF-1.

CONCLUSION

Local administration of high-dose 80 µg/kg IGF-1 enhances mandibular growth and condylar bone quality and quantity in growing rats. The findings have implications for modulating mandibular growth and potentially enhancing condylar bone health and integrity.

Lactobacillus fermentum (MTCC-5898) alleviates Escherichia coli-induced inflammatory responses in intestinal epithelial cells by modulating immune genes and NF-κB signalling

AIM

Dietary intervention using probiotic bacteria has emerged as a promising preventive strategy in addressing foodborne infections or gastrointestinal disorders. This study investigated the immunomodulatory effects of Lactobacillus fermentum (MTCC-5898) on Escherichia coli-induced inflammatory responses in intestinal epithelial cells.

METHODS AND RESULTS

The immune response of intestinal cells (Caco-2) in the presence of probiotic Lact. fermentum was determined during exclusion, competition and displacement of E. coli as the inflammatory agent. To achieve this objective, transcriptional modulation of key immune-related genes (cytokines, pattern recognition receptors and NF-κB), release of cytokines and nuclear translocation of the NF-κB subunit p-65 were studied. Expression of pro-inflammatory cytokines IL-8, TNF-α, IFN-ϒ and IL-23 was high in E. coli-exposed intestinal cells. However, overexpression of these E. coli-induced pro-inflammatory cytokines was prevented by Lact. fermentum during exclusion and competition assays. It also modulated the transcriptional expression of regulatory cytokines (IL-10 and TGF-β), pattern recognition receptors (TLR-2 and TLR-4) and genes associated with master inflammatory regulators (NF-κB and SIGIRR) to reduce E. coli-induced inflammation. The protective effect of Lact. fermentum was further confirmed by suppression of nuclear translocation of cytoplasmic NF-κB subunit (p-65).

CONCLUSION

Lactobacillus fermentum alleviated E. coli-induced inflammatory responses by modulating the NF-κB signalling besides pro-inflammatory and regulatory cytokines expression.

SIGNIFICANCE AND IMPACT OF THE STUDY

Lactobacillus fermentum holds significant promise as a potent nutraceutical that prevents and manages inflammatory gut-associated dysfunctions.

Effect of orthodontic forces on levels of enzymes in gingival crevicular fluid (GCF): A systematic review

Objective:

Orthodontic force application releases multiple enzymes in gingival crevicular fluid (GCF) for activation, resorption, reversal, deposition of osseous elements and extracellular matrix degradation. The current systematic review critically evaluated all existing evidence on enzymes in orthodontic tooth movement.

Methods:

Literature was searched with predetermined search strategy on electronic databases (PubMed, Scopus, Embase), along with hand search.

Results:

Initial search identified 652 studies, shortlisted to 52 studies based on PRISMA. Quality assessment further led to final inclusion of 48 studies (13 moderately and 35 highly sensitive studies). Primary outcomes are significant upregulation in GCF levels of enzymes-aspartate aminotransferase (AST), alkaline phosphatase (ALP), matrix metalloproteinases (MMPs), lactate dehydrogenase (LDH), β-glucuronidase (βG), tartrate resistant acid phosphatase (TRAP), acid phosphatase (ACP) and down regulation in cathepsin B (Cb). Site specificity is shown by ALP, TRAP, AST, LDH, MMP9 with levels at compression site increasing earlier and in higher quantities compared with tension site. ALP levels are higher at tension site only in retention. A positive correlation of LDH, ALP and AST is also observed with increasing orthodontic force magnitude.

Conclusions:

A strong evidence of variation in enzymes (ALP, AST, ACP TRAP, LDH, MMPs, Cb) in GCF is found in association with different magnitude, stages and sites of orthodontic force application.

Preface to COAST 2018 Innovators' Workshop: Bridging the biology and technology gap in orthodontics and craniofacial care

OBJECTIVE

A third focused workshop explored how to transfer novel findings into clinical orthodontic practice.

SETTING AND SAMPLE POPULATION

Participants met at the Scottsdale Plaza Resort, 12-16 September 2018 for the Consortium for Orthodontic Advances in Science and Technology 2018 Innovators' Workshop. Thirty speakers and four lunch-hour focus group leaders shared and exchanged information with approximately 45 registered attendees.

MATERIAL AND METHODS

This Innovators' Workshop was organized according to five themed sessions which covered: (a) The relevance of genetics, biology and environment to therapeutic outcomes; (b) Application of bioinformatics in craniofacial research; (c) Regeneration with and for orthodontic treatment; (d) Technology in precision orthodontics; and (e) Muscle, joint, and airway: Growth, function and pain.

RESULTS

The papers that comprise this supplemental issue exemplify the important outcomes of the 2018 COAST Workshop. In addition, matters identified as important needs include improved understanding of neural, skeletal and muscle tissue crosstalk in early craniofacial growth; standardized methods for three-dimensional radiographic and surface landmark and reference plane identification, measurements and serial superimpositioning techniques for use in the clinic; sharing and making available existing data sets (eg, cone beam computed tomography images, genotype-phenotype data); evidence of the usefulness and effectiveness of new devices; guidelines of what to measure to characterize the airway; more information about the influences of the soft tissues on craniofacial morphology; and information about effective digital work flows applied to clinical and educational settings.

CONCLUSIONS

Progress in bridging the biology-technology gap has identified new needs for improvements in orthodontics and craniofacial care.

Temporomandibular Joint Bioengineering Conference: Working Together Toward Improving Clinical Outcomes

The sixth temporomandibular joint (TMJ) Bioengineering Conference (TMJBC) was held on June 14-15 2018, in Redondo Beach, California, 12 years after the first TMJBC. Speakers gave 30 presentations and came from the United States, Europe, Asia, and Australia. The goal of the conference has remained to foster a continuing forum for bioengineers, scientists, and surgeons and veterinarians to advance technology related to TMJ disorders. These collective multidisciplinary interactions over the past decade have made large strides in moving the field of TMJ research forward. Over the past 12 years, in vivo approaches for tissue engineering have emerged, along with a wide variety of degeneration models, as well as with models occurring in nature. Furthermore, biomechanical tools have become more sensitive and new biologic interventions for disease are being developed. Clinical directives have evolved for specific diagnoses, along with patient-specific biological and immunological responses to TMJ replacement devices alloplastic and/or bioengineered devices. The sixth TMJBC heralded many opportunities for funding agencies to advance the field: (1) initiatives on TMJ that go beyond pain research, (2) more training grants focused on graduate students and fellows, (3) partnership funding with government agencies to translate TMJ solutions, and (4) the recruitment of a critical mass of TMJ experts to participate on grant review panels. The TMJ research community continues to grow and has become a pillar of dental and craniofacial research, and together we share the unified vision to ultimately improve diagnoses and treatment outcomes in patients affected by TMJ disorders.

Estrogen Selectively Enhances TMJ Disc but Not Knee Meniscus Matrix Loss

The preponderance of temporomandibular joint (TMJ) degenerative disorders in women and their early onset during reproductive years have implicated female sex hormones, particularly 17-β estradiol (E2), in the pathogenesis of these disorders. Nevertheless, the mechanisms by which E2 contributes to TMJ degenerative disorders and the reasons for its targeted effects on the TMJ but not other joints remain poorly understood. Here, we developed an ovariectomized mouse model in which systemic E2 concentrations mimicked those in cycling women, and we determined the effect of E2 on the targeted turnover of TMJ fibrocartilage matrix via E2-induced matrix metalloproteinases MMP9 and MMP13. Infusion of E2 and progesterone (P4; hormone control) over 7 d resulted in 5- and 8-fold greater serum E2 and P4 levels relative to controls, respectively, achieving systemic hormone levels similar to high baseline levels in cycling women. Administration of E2 but not P4 caused a significant loss of TMJ collagen and glycosaminoglycans, which was accompanied by amplification of ERα and specific increases in MMP9 and MMP13 expression. This dose of E2 had no effect on knee meniscus fibrocartilage, demonstrating the specificity of the degradative effect of E2. Dose-response experiments showed a greater sensitivity and a higher peak induction of MMP9 and MMP13 in TMJ fibrocartilaginous cells than knee meniscus cells to E2, providing an explanation for the differential responses of these tissues to E2. Using MMP9- and MMP13-null mice, we observed no discernible effects of each proteinase individually to E2-mediated TMJ matrix loss but noted a significant compensatory reciprocal induction of each MMP by E2 in the absence of the other. The redundancy in E2's induction of MMP9 and MMP13 suggests that the proteinases may together contribute to E2-mediated TMJ fibrocartilage loss. These results advance our understanding of E2-mediated upregulation of MMP9 and MMP13 on fibrocartilage matrix turnover targeted to the TMJ.

Microsphere controlled drug delivery for local control of tooth movement

Background

Because orthodontic tooth movement is dependent upon osteoclast-mediated resorption of alveolar bone adjacent to the pressure side of tooth roots, biologic mediators that regulate osteoclasts can be utilized to control tooth movement.

Objectives

To develop a novel method to locally enhance orthodontic anchorage.

Methods

We encapsulated osteoprotegerin (OPG) in polymer microspheres and tested the effectiveness of microsphere encapsulated versus non-encapsulated OPG for enhancing orthodontic anchorage in a rodent model of tooth movement. A single injection of 1 mg/kg non-encapsulated or microsphere encapsulated OPG was delivered into the palatal mucosa mesial to the first maxillary molar 1 day prior to tooth movement. A positive control group received injections of 5 mg/kg non-encapsulated OPG every 3 days during tooth movement. After 28 days of tooth movement, hemi-maxillae and femurs were dissected. Molar mesial and incisor distal tooth movement was measured using stone casts that were scanned and magnified. Local alveolar, distant femur bone, and tooth root volumes were analyzed by micro computed tomography. Serum OPG levels were measured by ELISA. Osteoclast numbers were quantified by histomorphometry.

Results

The single injection of microsphere encapsulated OPG significantly enhanced orthodontic anchorage, while the single injection of non-encapsulated OPG did not. Injection of encapsulated OPG inhibited molar mesial movement but did not inhibit incisor tooth movement, and did not alter alveolar or femur bone volume fraction, density, or mineral content. Multiple injections of 5 mg/kg non-encapsulated OPG enhanced orthodontic anchorage, but also inhibited incisor retraction and altered alveolar and femur bone quality parameters. Increased OPG levels were found only in animals receiving multiple injections of non-encapsulated 5 mg/kg OPG. Osteoclast numbers were higher upon tooth movement in animals that did not receive OPG. Osteoclast numbers in OPG injected animals were variable within groups.

Conclusions

Microsphere encapsulation of OPG allows for controlled drug release, and enhances site-specific orthodontic anchorage without systemic side effects. With additional refinements, this drug delivery system could be applicable to a broad array of potential biologic orthodontic therapeutics.

Moving towards precision orthodontics: An evolving paradigm shift in the planning and delivery of customized orthodontic therapy

Advances in precision medicine portend similar progress in orthodontics and will be increasingly harnessed to achieve customized treatment approaches and enhance treatment efficiencies. Our goal is to provide a background on emerging advances in computer technologies and biomedicine and highlight their current and likely future applications to precision orthodontics. A review of orthodontically relevant technologies and advances in pertinent biological research was undertaken. Innovations in computer hardware and software, and 3D imaging technologies offer the ability for customized treatment and biomechanical planning that will be more fully realized within the next few decades. These technologies combined with 3D printing are already being applied to customized appliance fabrication such as aligners and retainers. The future prospects for custom fabrication of orthodontic brackets of appropriate material properties and smart devices are highly desirable and compelling goals. Within biomedicine, the fundamental understanding of cartilage growth and bone biology is currently being tested in animal models to modify mandibular growth and modulate tooth movement, respectively. Some of these discoveries will ultimately have clinical applications in orthodontics including for growth modification, accelerating orthodontic tooth movement, and enhancing anchorage or retention of teeth. Additional genomic and proteomic information will add to further customization of orthodontic diagnosis and treatments. Over the coming decades, precision orthodontics will continue to benefit from advances in many fields and will require the integration of advances in technology, and biomedical and clinical research to deliver optimal, efficient, safe, and reproducible personalized orthodontic treatment.

17β-estradiol Induces MMP-9 and MMP-13 in TMJ Fibrochondrocytes via Estrogen Receptor α

Temporomandibular joint (TMJ) disorders, including degenerative TMJ disease, occur primarily in women of reproductive age. Previous studies showed elevated estrogen levels in subjects with TMJ disorders relative to controls and the presence of estrogen receptors α and β (ERα and ERβ) in TMJ fibrocartilage. Additionally, estrogen-induced overexpression of specific matrix metalloproteinases (MMPs), including MMP-9 and MMP-13, in TMJ fibrocartilage is accompanied by loss of extracellular matrices. However, the contribution of ERα and ERβ in estrogen-mediated induction of MMP-9 and MMP-13 and the signaling cascade leading to the upregulation of these MMPs have not been elucidated. Here, we show that specific siRNAs and selective ER antagonists effectively block ERα or ERβ expression in primary mouse TMJ fibrochondrocytes, but that only blockage of ERα suppresses MMP-9 and MMP-13 levels induced by 17β-estradiol (E2). Overexpression of ERα but not ERβ enhances E2-induced MMP-9. Using the same loss-of-function and gain-of-function approaches, we demonstrate that E2 stimulates ERK activation through ERα and that inhibition of ERK phosphorylation reduces E2-induced MMP-9. Furthermore, we reveal that E2 promotes NF-κB and ELK-1 activation through ERα/ERK signaling and that knockdown of either one decreases the respective activity of these signaling mediators and MMP-9 expression induced by E2, indicating that both contribute to E2/ERα/ERK-mediated MMP-9 upregulation. This is supported by findings in which mutated binding sites of either NF-κB or ELK-1 in the MMP-9 promoter lead to a significant reduction of E2-stimulated promoter activity. Our findings provide novel molecular mechanisms for the understanding of E2-mediated upregulation of MMPs, having implications to pathophysiologic TMJ cartilage matrix turnover that may yield therapeutic intervention targets for TMJ disorders.

Selective Role of Discoidin Domain Receptor 2 in Murine Temporomandibular Joint Development and Aging

Temporomandibular joint (TMJ) disorders are often associated with development of osteoarthritis-like changes in the mandibular condyle. Discoidin domain receptor 2 (DDR2), a collagen receptor preferentially activated by type I and III collagen found in the TMJ and other fibrocartilages, has been associated with TMJ degeneration, but its role in normal joint development has not been previously examined. Using Ddr2 LacZ-tagged mice and immunohistochemistry, we found that DDR2 is preferentially expressed and activated in the articular zone of TMJs but not knee joints. To assess the requirement for Ddr2 in TMJ development, studies were undertaken to compare wild-type and smallie ( slie) mice, which contain a spontaneous deletion in Ddr2 to produce an effective null allele. Analysis of TMJs from newborn Ddr2^slie/slie mice revealed a developmental delay in condyle mineralization, as measured by micro-computed tomography and histologic analysis. In marked contrast, knee joints of Ddr2^slie/slie mice were normal. Analysis of older Ddr2^slie/slie mice (3 and 10 mo) revealed that the early developmental delay led to a dramatic and progressive loss of TMJ articular integrity and osteoarthritis-like changes. Mutant condyles had a rough and flattened bone surface, accompanied by a dramatic loss of bone mineral density. Mankin scores showed significantly greater degenerative changes in the TMJs of 3- and 10-mo-old Ddr2^slie/slie mice as compared with wild-type controls. No DDR2-dependent degenerative changes were seen in knees. Analysis of primary cultures of TMJ articular chondrocytes from wild-type and Ddr2^slie/slie mice showed defects in chondrocyte maturation and mineralization in the absence of Ddr2. These studies demonstrate that DDR2 is necessary for normal TMJ condyle development and homeostasis and that these DDR2 functions are restricted to TMJ fibrocartilage and not seen in the hyaline cartilage of the knee.

Glutathione biosynthesis and activity of dependent enzymes in food-grade lactic acid bacteria harbouring multidomain bifunctional fusion gene (gshF)

AIMS

To assess glutathione (GSH) biosynthesis ability and activity of dependent enzymes in food-grade lactic acid bacteria (LAB) and correlating with genomic information on GSH system in LAB.

METHODS AND RESULTS

Whole-genome sequences of 26 food-grade LAB were screened for the presence/absence of a set of genes involved in de novo GSH system. Multiple strains of Streptococcus thermophilus (37), Lactobacillus casei (37), Lactobacillus rhamnosus (4), Lactobacillus paracasei (8) Lactobacillus plantarum (23) and Lactobacillus fermentum (22) were screened for biochemical evidence of the GSH system. Multiple sequence analysis of GshF sequences was carried out for comparing the genomic signatures between GSH-producing and nonproducing species.

CONCLUSIONS

Streptococcus thermophilus was found to have de novo GSH biosynthesis as well as import ability. Lactobacillus sp. were negative for GSH synthesis but could import it from the medium. All the species exhibited prolific GSH reductase and peroxidase activity. Sequence analysis revealed the absence of key amino acid residues as well as a truncated N-terminal region in lactobacilli.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study provides a comprehensive view on the status of an important antioxidative system (the GSH system) in LAB and is expected to serve as a primer for future work on the mechanistic role of GSH in the group.

Protective effects of casein-derived peptide VLPVPQK against hydrogen peroxide–induced dysfunction and cellular oxidative damage in rat osteoblastic cells

Oxidative stress inhibits osteoblast differentiation and function that lead to the development of osteoporosis. Casein-derived peptide VLPVPQK (PEP), a potent antioxidant, was isolated from β-casein of buffalo milk. We used an in vitro oxidative stress model induced by hydrogen peroxide (H2O2) in rat osteoblastic cells to investigate the protective effects of PEP against H2O2-induced dysfunction and oxidative damage. Cells were pretreated with PEP (50–200 ng/mL) for 2, 7 or 21 days followed by 0.3 mM H2O2 treatment for 24 h and then markers of osteogenic development, oxidative damage and apoptosis were examined. PEP significantly increased the viability and differentiation markers of osteoblast cells such as alkaline phosphatase and calcium mineralization. Moreover, PEP suppressed the production of reactive oxygen species (ROS), lipid peroxidation and ameliorated H2O2-induced reduction in glutathione, superoxide dismutase and catalase activities. In addition, PEP partially inhibited caspase-9 and-3 activities and reduced propidium iodide–positive cells. Altogether, our results demonstrated that PEP could protect rat osteoblast against H2O2-induced dysfunction and oxidative damage by reduction of ROS production, lipid peroxidation and increased antioxidant enzyme activities. Thus, our data suggest that PEP might be a valuable protective agent against oxidative stress–related diseases such as osteoporosis.

Cyclic Mechanical Strain Regulates the PTHrP Expression in Cultured Chondrocytes via Activation of the Ca2+ Channel

The association between mechanical stimulation and chondrocyte homeostasis has been reported. However, the participation of PTHrP (parathyroid-hormone-related protein) in the mechano-regulation of chondrocyte metabolism remains unclear. We determined whether mechanical stimulation of chondrocytes induces the expression of PTHrP and, further, whether the mechano-modulation of PTHrP is dependent on the maturational status of chondrocytes. Cyclic mechanical strain was applied to rat growth plate chondrocytes at the proliferating, matrix-forming, and hypertrophic stages at 30 cycles/min. Cyclic mechanical strain significantly increased PTHrP mRNA levels in chondrocytes at the proliferating and matrix-forming stages only. The induction of PTHrP was dependent on loading magnitude at the proliferating stage. Using specific ion channel blockers, we determined that mechano-induction of PTHrP was inhibited by nifedipine, a Ca2+ channel blocker. These results suggest that mechanical induction of PTHrP possibly provides the environment for greater chondrocyte replication and matrix formation that would subsequently affect cartilage formation.

Personalized and precision orthodontic therapy

OBJECTIVE

To bring together orthodontic stakeholders from academics, industry, and private practice for a series of thematically focused workshops to explore and develop the transfer of novel approaches into clinical orthodontic practice.

SETTING AND SAMPLE POPULATION

Twenty-seven invited speakers, eight poster presenters, and participants of the Consortium for Orthodontic Advances in Science and Technology (COAST) 2014 Innovators' Workshop at the Eaglewood Resort and Spa, Itasca, Illinois, September 11-14, 2014.

MATERIAL AND METHODS

Five themed sessions involving between 4-7 presentations followed by panel discussions were organized. The aims of the discussion sessions were to highlight important findings and consider the strength of evidence for these, indicate next steps and needed research or technological developments to move forward, and to weigh the expected benefits from these findings and steps to implement in clinical practice.

RESULTS

Among important areas for attention identified were need for multiscale and multispecies modeling and experimentation for interspecies translation of results; large-scale collaborative efforts within the profession to address the need for adequate sample sizes for future genetic studies of complex traits such as malocclusion; a consortium approach to improve new technologies such as intra-oral scanning and 3D imaging by establishing standards; and harnessing the growing body of knowledge about bone biology for application in orthodontics.

CONCLUSIONS

With increased awareness of the potential of current and emerging technologies, translation of personalized and precision approaches in the field of orthodontics holds ever-increasing promise.

3D superimposition and understanding temporomandibular joint arthritis

OBJECTIVES

To investigate the 3D morphological variations in 169 temporomandibular ioint (TMJ) condyles, using novel imaging statistical modeling approaches.

SETTING AND SAMPLE POPULATION

The Department of Orthodontics and Pediatric Dentistry at the University of Michigan. Cone beam CT scans were acquired from 69 subjects with long-term TMJ osteoarthritis (OA, mean age 39.1±15.7 years), 15 subjects at initial consult diagnosis of OA (mean age 44.9±14.8 years), and seven healthy controls (mean age 43±12.4 years).

MATERIALS AND METHODS

3D surface models of the condyles were constructed, and homologous correspondent points on each model were established. The statistical framework included Direction-Projection-Permutation (DiProPerm) for testing statistical significance of the differences between healthy controls and the OA groups determined by clinical and radiographic diagnoses.

RESULTS

Condylar morphology in OA and healthy subjects varied widely with categorization from mild to severe bone degeneration or overgrowth. DiProPerm statistics supported a significant difference between the healthy control group and the initial diagnosis of OA group (t=6.6, empirical p-value=0.006) and between healthy and long-term diagnosis of OA group (t=7.2, empirical p-value=0). Compared with healthy controls, the average condyle in OA subjects was significantly smaller in all dimensions, except its anterior surface, even in subjects with initial diagnosis of OA.

CONCLUSION

This new statistical modeling of condylar morphology allows the development of more targeted classifications of this condition than previously possible.

Locally limited inhibition of bone resorption and orthodontic relapse by recombinant osteoprotegerin protein

OBJECTIVES

To determine minimal dose levels required for local inhibition of orthodontic relapse by recombinant OPG protein (OPG-Fc), while also determining effects of injected OPG-Fc on alveolar bone and long bone.

SETTING AND SAMPLE POPULATION

The Department of Orthodontics and Pediatric Dentistry at the University of Michigan. Eighteen male Sprague Dawley rats.

MATERIALS & METHODS

Maxillary molars were moved with nickel-titanium springs and then allowed to relapse in Sprague Dawley rats. Upon appliance removal, animals were injected with a single dose of 1.0 mg/kg OPG-Fc, 0.1 mg/kg OPG-Fc, or phosphate-buffered saline (vehicle) just distal to the molar teeth. Tooth movement measurements were made from stone casts, which were scanned and digitally measured. Alveolar tissues were examined by histology. Micro-computed tomography was used to quantify changes in alveolar and femur bone.

RESULTS

Local injection of OPG-Fc inhibited molar but not incisor relapse, when compared to vehicle-injected animals. No significant differences in alveolar or femur bone were seen between the three treatment groups after 24 days of relapse.

CONCLUSIONS

Our results demonstrate that a single local injection of OPG-Fc effectively inhibits orthodontic relapse, with minimal systemic bone metabolic effects. Our results also show that a single injection of OPG-Fc will influence tooth movement only in teeth close to the injection site. These findings indicate that OPG-Fc has potential as a safe and effective pharmacological means to locally control osteoclasts, for uses such as maintaining anchorage during orthodontic tooth movement and preventing orthodontic relapse in humans.

Three-Dimensional Force Measurements During Rapid Palatal Expansion in Sus scrofa

Rapid palatal expansion is an orthodontic procedure widely used to correct the maxillary arch. However, its outcome is significantly influenced by factors that show a high degree of variability amongst patients. The traditional treatment methodology is based on an intuitive and heuristic treatment approach because the forces applied in the three dimensions are indeterminate. To enable optimal and individualized treatment, it is essential to measure the three-dimensional (3D) forces and displacements created by the expander. This paper proposes a method for performing these 3D measurements using a single embedded strain sensor, combining experimental measurements of strain in the palatal expander with 3D finite element analysis (FEA). The method is demonstrated using the maxillary jaw from a freshly euthanized pig (Sus scrofa) and a hyrax-design rapid palatal expander (RPE) appliance with integrated strain gage. The strain gage measurements are recorded using a computer interface, following which the expansion forces and extent of expansion are estimated by FEA. A total activation of 2.0 mm results in peak total force of about 100 N-almost entirely along the direction of expansion. The results also indicate that more than 85% of the input activation is immediately transferred to the palate and/or teeth. These studies demonstrate a method for assessing and individualizing expansion magnitudes and forces during orthopedic expansion of the maxilla. This provides the basis for further development of smart orthodontic appliances that provide real-time readouts of forces and movements, which will allow personalized, optimal treatment.

Immortalization and characterization of mouse temporomandibular joint disc cell clones with capacity for multi-lineage differentiation

OBJECTIVE

Despite the importance of temporomandibular joint (TMJ) disc in normal function and disease, studying the responses of its cells has been complicated by the lack of adequate characterization of the cell subtypes. The purpose of our investigation was to immortalize, clone, characterize and determine the multi-lineage potential of mouse TMJ disc cells.

DESIGN

Cells from 12-week-old female mice were cultured and immortalized by stable transfection with human telomerase reverse transcriptase (hTERT). The immortalized cell clones were phenotyped for fibroblast- or chondrocyte-like characteristics and ability to undergo adipocytic, osteoblastic and chondrocytic differentiation.

RESULTS

Of 36 isolated clones, four demonstrated successful immortalization and maintenance of stable protein expression for up to 50 passages. Two clones each were initially characterized as fibroblast-like and chondrocyte-like on the basis of cell morphology and growth rate. Further the chondrocyte-like clones had higher mRNA expression levels of cartilage oligomeric matrix protein (COMP) (>3.5-fold), collagen X (>11-fold), collagen II expression (2-fold) and collagen II:I ratio than the fibroblast-like clones. In contrast, the fibroblast-like clones had higher mRNA expression level of vimentin (>1.5-fold), and fibroblastic specific protein 1 (>2.5-fold) than the chondrocyte-like clones. Both cell types retained multi-lineage potential as demonstrated by their capacity to undergo robust adipogenic, osteogenic and chondrogenic differentiation.

CONCLUSIONS

These studies are the first to immortalize TMJ disc cells and characterize chondrocyte-like and fibroblast-like clones with retained multi-differentiation potential that would be a valuable resource in studies to dissect the behavior of specific cell types in health and disease and for tissue engineering.

Abstract 4500: Nisin ZP, a food preservative, has antitumor potential for head and neck cancer and extends survival

The use of small antimicrobial agents or bacteriocins, like nisin, to treat cancer is a new approach that holds great promise. Nisin exemplifies this new approach because it has been used safely in humans for many years as a food preservative, and recent laboratory studies support its anti-tumor potential in head and neck cancer. Previously, we showed that nisin (2.5%, low content) has antitumor potential in head and neck squamous cell carcinoma (HNSCC) in vitro and in vivo. The current studies explored a naturally occurring variant of nisin (nisin ZP; 95%, high content) for its antitumor effects in vitro and in vivo. Nisin ZP induced the greatest level of apoptosis in HNSCC cells compared to low content nisin. HNSCC cells treated with increasing concentrations of nisin ZP exhibited increasing levels of apoptosis and decreasing levels of cell proliferation and clonogenic capacity. Nisin ZP-induced apoptosis was defined by increased ethidium bromide and acridine orange (EB/AO) staining and by increased levels of calpain-dependent PARP cleavage. Importantly, nisin ZP also induced apoptosis dose-dependently in HUVEC endothelial cells and concomitant decreases in vascular sprout formation. Nisin ZP inhibited sphere formation of HNSCC cells in vitro and tumorigenesis in vivo and long term treatment extended survival. In summary, nisin ZP exhibits greater antitumor effects than low content nisin, and thus has the potential to serve as a novel therapeutic for HNSCC.

Note: This abstract was not presented at the meeting.

Citation Format: Pachiyappan Kamarajan, Takayuki Hayami, Bibiana Matte, Yang Liu, Ayyalusamy Ramamoorthy, Francis P. Worden, Sunil Kapila, Yvonne Kapila. Nisin ZP, a food preservative, has antitumor potential for head and neck cancer and extends survival. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4500. doi:10.1158/1538-7445.AM2015-4500

Effect of orthodontic forces on cytokine and receptor levels in gingival crevicular fluid: a systematic review

This systematic review aimed to generate evidence on role of potent markers of inflammation [cytokines, chemokines, their associated receptors and antagonists] following the application of orthodontic forces. Subsequent to registration with PROSPERO, literature search followed a predetermined search strategy to key databases along with hand search (HS). Seventy-seven articles from PubMed (P), 637 from Scopus (S), 51 from Embase (E), and 3 from hand search (HS) were identified. A total of 39 articles were shortlisted that met strict inclusion and exclusion criteria and quality assessment. Each study was evaluated for participant characteristics, study design, oral hygiene regimen, and gingival crevicular fluid (GCF) handling. Among these studies, biomarkers in the order of frequency were interleukin (IL)-1β (N = 21), tumor necrosis factor (TNF)-α (N = 10), IL-8,IL-6(N=8), receptor activator of nuclear factor kappa-B ligand (RANKL) (N = 7), monocyte chemoattractant protein (MCP)-1 (N = 3), IL-2 (N=4), IL-4, IL-10, RANTES (N = 2), IL-1, IL-5, IL-1α, IP-10, osteopontin (OPN) (N = 1) and receptors and their antagonists in the order of osteoprotegerin (OPG) (N = 8), IL-1RA (N = 5), and RANK (N = 1). Results revealed an immediate release of inflammatory bone-resorptive mediators, IL-1β and TNF-α, where IL-1β increased as early as 1 min to 1 h reaching peak at 24 h while TNF-α increased at 1 h or 1 day. This was accompanied by a fall in bone-protective mediator (OPG) levels at 1 h and 24 h after orthodontic force application. Continuous forces were accompanied by a decrease in mediator levels after attaining peak levels (most commonly at 24 h) while repeated activations in interrupted force upregulated their secretion. Significant correlations of IL-1β levels with pain intensity, rate of orthodontic tooth movement (OTM) and of activity index (AI) (IL-1β/IL-1RA) with velocity of tooth movement and growth status of individuals have also been deduced. A greater AI and RANKL/OPG ratio was seen in juveniles as compared to adults or non-growers that were associated with faster rate of OTM in juveniles. None of the studies addressed the effect of estrous cycle in female subjects. Lack of homogeneity in several parameters calls for a better controlled research on the biology of OTM.

3D osteoarthritic changes in TMJ condylar morphology correlates with specific systemic and local biomarkers of disease

OBJECTIVE

To assess 3D morphological variations and local and systemic biomarker profiles in subjects with a diagnosis of temporomandibular joint osteoarthritis (TMJ OA).

DESIGN

Twenty-eight patients with long-term TMJ OA (39.9 ± 16 years), 12 patients at initial diagnosis of OA (47.4 ± 16.1 years), and 12 healthy controls (41.8 ± 12.2 years) were recruited. All patients were female and had cone beam CT scans taken. TMJ arthrocentesis and venipuncture were performed on 12 OA and 12 age-matched healthy controls. Serum and synovial fluid levels of 50 biomarkers of arthritic inflammation were quantified by protein microarrays. Shape Analysis MANCOVA tested statistical correlations between biomarker levels and variations in condylar morphology.

RESULTS

Compared with healthy controls, the OA average condyle was significantly smaller in all dimensions except its anterior surface, with areas indicative of bone resorption along the articular surface, particularly in the lateral pole. Synovial fluid levels of ANG, GDF15, TIMP-1, CXCL16, MMP-3 and MMP-7 were significantly correlated with bone apposition of the condylar anterior surface. Serum levels of ENA-78, MMP-3, PAI-1, VE-Cadherin, VEGF, GM-CSF, TGFβb1, IFNγg, TNFαa, IL-1αa, and IL-6 were significantly correlated with flattening of the lateral pole. Expression levels of ANG were significantly correlated with the articular morphology in healthy controls.

CONCLUSIONS

Bone resorption at the articular surface, particularly at the lateral pole was statistically significant at initial diagnosis of TMJ OA. Synovial fluid levels of ANG, GDF15, TIMP-1, CXCL16, MMP-3 and MMP-7 were correlated with bone apposition. Serum levels of ENA-78, MMP-3, PAI-1, VE-Cadherin, VEGF, GM-CSF, TGFβ1, IFNγ, TNFα, IL-1α, and IL-6 were correlated with bone resorption.

Use of dermal injection of activated protein C for treatment of large chronic wounds secondary to pyoderma gangrenosum

BACKGROUND

Pyoderma gangrenosum (PG) is a systemic disease that presents with cutaneous necrotizing ulceration, producing deep necrotic ulcers, usually with a raised, undermined, violaceous border. Treatment typically involves high dose immunosuppressive drugs, but more recently anti-tumour necrosis factor and monoclonal antibodies have been used. Activated protein C (APC) stimulates wound healing in patients with treatment-refractory skin ulcers, possibly by stimulating angiogenesis and re-epithelialization, and preventing inflammation.

AIM

To investigate whether APC may be beneficial as a treatment for ulcers related to cutaneous PG.

METHODS

Two patients were recruited with a clinical history and physical and histopathological evidence of acute PG. A total of 400 μg (1.0 mL) of APC was injected subcutaneously into the dermal edge of necrotic PG ulcers weekly for a total treatment period of 6 weeks. Photographs were taken, and clinical progress, ulcer size and pain score were monitored during this period and after the cessation of treatment, at weeks 8 and 12.

RESULTS

Over the 12 weeks of the trial, APC led to a reduction in wound size from 3.8 cm(2) to 0.8 cm(2) in patient 1 (78.9% decrease) and from 41 cm(2) to 16 cm(2) in patient 2 (70.0% decrease, respectively), and a reduction in pain scores from 10 to 0 (100% decrease) in both patients.

CONCLUSION

Although this study has limited because of its small sample size and lack of a true placebo group, it does indicate that APC has potential as a therapeutic option for patients with chronic skin ulcers from PG.

Cross-talk between probiotic lactobacilli and host immune system

The mechanism by which probiotic lactobacilli affect the immune system is strain specific. As the immune system is a multicompartmental system, each strain has its way to interact with it and induce a visible and quantifiable effect. This review summarizes the interplay existing between the host immune system and probiotic lactobacilli, that is, with emphasis on lactobacilli as a prototype probiotic genus. Several aspects including the bacterial-host cross-talk with the mucosal and systemic immune system are presented, as well as short sections on the competing effect towards pathogenic bacteria and their uses as delivery vehicle for antigens.

Induction of immune tolerance to caseins and whey proteins by oral intubation in mouse allergy model

This study was designed to evaluate the effect of oral tolerance of caseins (CSN) and whey proteins (WP) in alleviating the allergic response to cow's milk proteins in Swiss albino mice raised on a milk protein-free diet. Oral tolerance was induced by feeding mice with 20 mg of CSN or WP once in a day for 4 days consecutively before immunization with respective protein by intraperitoneal (i.p.) injections (20 μg 200 per μl of PBS) using 2% of alum Al(OH)3 as adjuvant. Three weeks later, oral tolerance induction was analysed in humoral and cellular compartments of CSN- and WP-fed versus saline-fed control mice groups by measuring seric and intestinal antibody responses, mRNA abundance in splenic tissue and cytokine secretion patterns. The specific serum immunoglobulin-E (IgE) levels were significantly suppressed (p < 0.05), while sIgA was enhanced in these groups when compared with their respective saline-fed mice. Moreover, the mRNA levels of interferon-γ (IFN-γ) and interleukin-4 (IL-4) in both CSN- and WP-tolerized mice were found to be significantly decreased, while the abundance of interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) was increased significantly, as compared to respective control groups. Finally, cytokine profiles indicated a reciprocal decrease in IL-4 and IFN-γ versus an increase in IL-10 secretions in supernatants of cultured splenocytes of tolerized mice. Taken together, these results clearly showed that oral administration of cows' milk caseins and whey proteins can induce significant hyposensitization in mice, with the participation of suppressor cytokines.

Relaxin induces matrix-metalloproteinases-9 and -13 via RXFP1: induction of MMP-9 involves the PI3K, ERK, Akt and PKC-ζ pathways

We determined the precise role of relaxin family peptide (RXFP) receptors-1 and -2 in the regulation of MMP-9 and -13 by relaxin, and delineated the signaling cascade that contributes to relaxin's modulation of MMP-9 in fibrocartilaginous cells. Relaxin treatment of cells in which RXFP1 was silenced resulted in diminished induction of MMP-9 and -13 by relaxin, whereas overexpression of RXFP1 potentiated the relaxin-induced expression of these proteinases. Suppression or overexpression of RXFP2 resulted in no changes in the relaxin-induced MMP-9 and -13. Studies using chemical inhibitors and siRNAs to signaling molecules showed that PI3K, Akt, ERK and PKC-ζ and the transcription factors Elk-1, c-fos and, to a lesser extent, NF-κB are involved in relaxin's induction of MMP-9. Our findings provide the first characterization of signaling cascade involved in the regulation of any MMP by relaxin and offer mechanistic insights on how relaxin likely mediates extracellular matrix turnover.

Local delivery of recombinant osteoprotegerin enhances postorthodontic tooth stability

Relapse after orthodontic tooth movement is a significant problem in orthodontics. The purpose of this study was to examine the efficacy of the osteoclast inhibitor osteoprotegerin-Fc (OPG-Fc) for inhibiting postorthodontic relapse. Rat maxillary molars were moved mesially and allowed to relapse for 24 days. Low-dose (1 mg/kg) or high-dose (5 mg/kg) OPG-Fc or saline was injected adjacent to the molars during relapse. Tooth movement, micro-CT, histologic bone quality, and serum OPG and TRAP-5b were measured. OPG-Fc injections significantly diminished postorthodontic relapse from 63% (0.78/1.20 mm) of total movement in vehicle control rats to 31% (0.31/1.00 mm) in low-dose and 24% (0.28/1.16 mm) in high-dose OPG-Fc groups 24 days after appliance removal. Normalization of bone and periodontal tissues occurred as early as 8 and 16 days in the high- and low-dose OPG-Fc-treated groups, respectively, while the vehicle-treated group showed only partial tissue recovery 24 days following tooth movement. After 24 days of relapse, there was complete recovery to pre-tooth-movement values for bone volume fraction (BVF) and tissue mineral density (TMD) in both the low- and high-dose OPG-Fc groups, while BVF recovered only partially and TMD did not recover in the vehicle control group. Greatly elevated serum OPG levels and reduced serum TRAP-5b levels in OPG-Fc-treated animals indicated systemic exposure to locally injected drug. The profound decrease in postorthodontic relapse by local OPG-Fc administration indicates that osteoclasts are critical to bone maturation following tooth movement and points to the potential pharmacologic use of OPG-Fc or other RANKL inhibitors for orthodontic retention.

Effect of supplementation of vitamin E, copper and zinc on the in vitro phagocytic activity and lymphocyte proliferation index of peripartum Sahiwal (Bos indicus) cows

To study the effect of vitamin E (VE), copper (Cu) and zinc (Zn) supplementation on the in vitro phagocytic activity (PA) and lymphocyte proliferation response (LPR) of blood neutrophils and lymphocytes, thirty Sahiwal pregnant cows (six in each group) in their late gestation at 30 days before the expected date of calving were selected from the NDRI experimental herd and supplemented with various micronutrients from 30 days before calving to 45 days after calving. Cows were supplemented individually with VE (1000 IU/cow/day), Cu (20 ppm/cow/day) and Zn (80 ppm/cow/day) and also with a combination of VE, Cu and Zn to study cumulative effect of all micronutrients. One group without any supplementation acted as a control. Blood neutrophils and lymphocytes were isolated and studied for their PA and LPR. Supplementation of micronutrients like VE, Cu, Zn and a combination of all these nutrients significantly (p < 0.01) increased the PA of experimental cows as compared to control (unsupplemented) cows during the pre-partum period. During post-partum, all the micronutrients (VE, Cu, Zn and their combination) showed a significant (p < 0.01) increase in the PA of experimental cows as compared to control cows. Of all the groups, significant (p < 0.01) and maximum PA was observed in the combination group followed by Zn-supplemented group during both the pre- and post-partum period. A significant (p < 0.01) increase in LPR of B lymphocytes was observed in combination-supplemented group during the pre-partum period and during both the pre- and post-partum period in the Cu-supplemented group.

Divergent upstream osteogenic events contribute to the differential modulation of MG63 cell osteoblast differentiation by MMP-1 (collagenase-1) and MMP-13 (collagenase-3)

Previously we showed that MMP-1 (collagenase-1) and MMP-13 (collagenase-3) differentially regulate the expression of osteoblastic markers in a heterogenous population of primary human periodontal ligament cells. The mechanisms for these differential responses are not known, but may result from divergence in regulation of early osteogenic transcription factors. The purpose of this study was to elucidate where in the hierarchy of osteoblast-specific transcription factors and markers the differences in MMP-1- and -13-mediated regulation of osteoblastic differentiation arise. We found that the overexpression of MMP-1 resulted in significant decreases in BMP-2, Dlx5, AP, OP and BSP and increases in TGF-β1 and MSX2. In contrast, MMP-13 overexpression resulted in significant decreases in Runx2, OP and BSP, and increases in TGF-β1, MSX2 and OC. The knockdown of MMP-1 caused significant increases in all osteoblastic markers. MMP-13 knockdown produced significant increases only in TGF-β1, MSX2 and Osx, but decreases in Runx2 and OC. Suppression of both MMPs together resulted in significant increases of all osteoblastic markers except Runx2. MMP-1 had a more robust and generalized effect in regulating osteoblast transcription factors and markers than MMP-13. Finally, of the markers and transcription factors assayed, Runx2 is the most early stage transcription factor induced by suppression of MMP-1, while Osx and MSX2 are the most early stage transcription factors regulated by MMP-13. These data show that MMP-1's and -13's differential regulation of osteoblastic markers in MG63 cells likely results from their modulation of divergent signaling pathways involved in osteoblastic differentiation.

In vitro phagocytic activity of milk neutrophils during lactation cycle in Murrah buffaloes of different parity

Milk samples were collected from 34 lactating Murrah buffaloes on days 0, 5, 15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 270 and day 300 after calving. Milk somatic cell counts (SCC) were highest in multiparous buffaloes. Milk SCC were significantly lower in buffaloes of third and fourth parity during early lactation and than increased significantly (p < 0.01) by the end of lactation. Milk neutrophils were significantly lower in all the buffaloes during early lactation, but increased significantly (p < 0.01) afterwards. Milk lymphocytes were significantly higher during early lactation, but decreased significantly (p < 0.01) by the end of lactation. Phagocytic activity (PA) was highest in day 1 colostrum and then decreased significantly (p < 0.01) by the fourth milking in buffaloes of second, third and fourth parity. Phagocytic index (PI) was also highest in colostrums of primiparous buffaloes. Irrespective of parity, maximum PA and PI was observed during mid lactation. In terms of in vitro phagocytic activity, early lactation is the most critical period followed by late and mid lactation.

The current status of cone beam computed tomography imaging in orthodontics

Cone beam CT (CBCT) has become an increasingly important source of three dimensional (3D) volumetric data in clinical orthodontics since its introduction into dentistry in 1998. The purpose of this manuscript is to highlight the current understanding of, and evidence for, the clinical use of CBCT in orthodontics, and to review the findings to answer clinically relevant questions. Currently available information from studies using CBCT can be organized into five broad categories: 1, the assessment of CBCT technology; 2, its use in craniofacial morphometric analyses; 3, incidental and missed findings; 4, analysis of treatment outcomes; and 5, efficacy of CBCT in diagnosis and treatment planning. The findings in these topical areas are summarized, followed by current indications and protocols for the use of CBCT in specific cases. Despite the increasing popularity of CBCT in orthodontics, and its advantages over routine radiography in specific cases, the effects of information derived from these images in altering diagnosis and treatment decisions has not been demonstrated in several types of cases. It has therefore been recommended that CBCT be used in select cases in which conventional radiography cannot supply satisfactory diagnostic information; these include cleft palate patients, assessment of unerupted tooth position, supernumerary teeth, identification of root resorption and for planning orthognathic surgery. The need to image other types of cases should be made on a case-by-case basis following an assessment of benefits vs risks of scanning in these situations.

Calcium hydroxide promotes cementogenesis and induces cementoblastic differentiation of mesenchymal periodontal ligament cells in a CEMP1- and ERK-dependent manner

Periodontal tissue engineering is a complex process requiring the regeneration of bone, cementum, and periodontal ligament (PDL). Since cementum regeneration is poorly understood, we used a dog model of dental pulpal necrosis and in vitro cellular wounding and mineralization assays to determine the mechanism of action of calcium hydroxide, Ca(OH)(2), in cementogenesis. Laser capture microdissection (LCM) followed by qRT-PCR were used to assay responses of periapical tissues to Ca(OH)(2) treatment. Additionally, viability, proliferation, migration, and mineralization responses of human mesenchymal PDL cells to Ca(OH)(2) were assayed. Finally, biochemical inhibitors and siRNA were used to investigate Ca(OH)(2)-mediated signaling in PDL cell differentiation. In vivo, Ca(OH)(2)-treated teeth formed a neocementum in a STRO-1- and cementum protein-1 (CEMP1)-positive cellular environment. LCM-harvested tissues adjacent to the neocementum exhibited higher mRNA levels for CEMP1, integrin-binding sialoprotein, and Runx2 than central PDL cells. In vitro, Ca(OH)(2) and CEMP1 promoted STRO-1-positive cell proliferation, migration, and wound closure. Ca(OH)(2) stimulated expression of the cementum-specific proteins CEMP1 and PTPLA/CAP in an ERK-dependent manner. Lastly, Ca(OH)(2) stimulated mineralization by CEMP1-positive cells. Blocking CEMP1 and ERK function abolished Ca(OH)(2)-induced mineralization, confirming a role for CEMP1 and ERK in the process. Ca(OH)(2) promotes cementogenesis and recruits STRO-1-positive mesenchymal PDL cells to undergo cementoblastic differentiation and mineralization via a CEMP1- and ERK-dependent pathway.

Disease-associated extracellular matrix suppresses osteoblastic differentiation of human periodontal ligament cells via MMP-1

Fibronectin (FN) fragments found in chronic inflammatory diseases, including periodontal disease and arthritis, may contribute to tissue destruction in part via induction of matrix metalloproteinases (MMPs). We previously showed that the 120-kDa FN fragment containing the central cell binding domain (120FN) dose dependently induces MMP-1 (collagenase-1) in human periodontal ligament (PDL) cells, whereas intact FN did not elicit this response. Recently, we found that an increase in MMP-1 expression is accompanied by a decreased osteoblastic phenotype in PDL cells. We hypothesized that 120FN inhibits osteoblastic differentiation of PDL cells by inducing MMP-1. Effects of increasing concentrations of 120FN on MMP-1 expression and on osteoblastic markers were assessed in cultured PDL cells using Western blotting, qRT-PCR, and collagen degradation and alkaline phosphatase (AP) activity assays. The 120FN dose dependently increased MMP-1 expression and activity, concomitant with a decrease in AP activity. The increase in collagenase activity was largely attributed to increased MMP-1 expression. Concurrent with the decrease in AP activity, the 120FN reduced baseline and dexamethasone-induced gene expression of specific osteoblastic markers, Runx2 and osteonectin, and diminished mineralized nodule formation. Finally, siRNA inhibition of 120FN-induced MMP-1 reduced collagenase expression and rescued the AP phenotype to baseline levels. These findings suggest that disease-associated 120FN, in addition to having direct effects on tissue destruction by upregulating MMPs, could contribute to disease progression by impeding osteoblastic differentiation of osteogenic PDL cells and, consequently, diminish bone regeneration.

Induction of MMP-1 (collagenase-1) by relaxin in fibrocartilaginous cells requires both the AP-1 and PEA-3 promoter sites

OBJECTIVES - Relaxin induces the matrix metalloproteinase MMP-1 (collagenase-1) in TMJ fibrocartilaginous cells, and this response is potentiated by beta-estradiol. We identified the MMP-1 promoter sites and transcription factors that are induced by relaxin with or without beta-estradiol in fibrocartilaginous cells. MATERIAL AND METHODS - Early passage cells were transiently transfected with the pBLCAT2 plasmid containing specific segments of the human MMP-1 promoter regulating the chloramphenicol acyl transferase (CAT) gene and co-transfected with a plasmid containing the beta-galactosidase gene. The cells were cultured in serum-free medium alone or medium containing 0.1 ng/ml relaxin, or 20 ng/ml beta-estradiol or both hormones, and lysates assayed for CAT and beta-galactosidase activity. RESULTS - Cells transfected with the -1200/-42 or -139/-42 bp MMP-1 promoter-reporter constructs showed 1.5-fold and 3-fold induction of CAT by relaxin in the absence or presence of beta-estradiol, respectively. Relaxin failed to induce CAT in the absence of the -137/-69 region of the MMP-1 promoter, which contains the AP-1-and PEA3-binding sites. Using wild type or mutated minimal AP-1 and PEA-3 promoters we found that both these promoter sites are essential for the induction of MMP-1 by relaxin. The mRNAs for transcription factors c-fos and c-jun, which together form the AP-1 heterodimer, and Ets-1 that modulates the PEA-3 site, were upregulated by relaxin or beta-estradiol plus relaxin. CONCLUSION - These studies show that both the AP-1 and PEA-3 promoter sites are necessary for the induction of MMP-1 by relaxin in fibrocartilaginous cells.