MyD88 exacerbates inflammation-induced bone loss by modulating dynamic equilibrium between Th17/Treg cells and subgingival microbiota dysbiosis

BACKGROUND

This study aimed to investigate the contribution of myeloid differentiation primary-response gene 88 (MyD88) on the differentiation of T helper type 17 (Th17) and regulatory T (Treg) cells and the emerging subgingival microbiota dysbiosis in Porphyromonas gingivalis-induced experimental periodontitis.

METHODS

Alveolar bone loss, infiltrated inflammatory cells, immunostained cells for tartrate-resistant acid phosphatase (TRAP), the receptor activator of nuclear factor-kB ligand (RANKL), and osteoprotegerin (OPG) were quantified by microcomputerized tomography and histological staining between age- and sex-matched homozygous littermates (wild-type [WT, Myd88+/+] and Myd88-/- on C57BL/6 background). The frequencies of Th17 and Treg cells in cervical lymph nodes (CLNs) and spleen were determined by flow cytometry. Cytokine expression in gingival tissues, CLNs, and spleens were studied by quantitative polymerase chain reaction (qPCR). Analysis of the composition of the subgingival microbiome and functional annotation of prokaryotic taxa (FAPROTAX) analysis were performed.

RESULTS

P. gingivalis-infected Myd88-/- mice showed alleviated bone loss, TRAP+ osteoclasts, and RANKL/OPG ratio compared to WT mice. A significantly higher percentage of Foxp3+CD4+ T cells in infected Myd88-/- CLNs and a higher frequency of RORγt+CD4+ T cells in infected WT mice was noted. Increased IL-10 and IL-17a expressions in gingival tissue at D14-D28 then declined in WT mice, whereas an opposite pattern was observed in Myd88-/- mice. The Myd88-/- mice exhibited characteristic increases in gram-positive species and species having probiotic properties, while gram-negative, anaerobic species were noted in WT mice. FAPROTAX analysis revealed increased aerobic chemoheterotrophy in Myd88-/- mice, whereas anaerobic chemoheterotrophy was noted in WT mice after P. gingivalis infection.

CONCLUSIONS

MyD88 plays an important role in inflammation-induced bone loss by modulating the dynamic equilibrium between Th17/Treg cells and dysbiosis in P. gingivalis-induced experimental periodontitis.

Wintersweet (Chimonanthus praecox) toxicity in 5 sheep

Two sheep presented with acute tonic-clonic seizures, opisthotonos, absent pupillary light reflexes and abnormal vital signs within 18 hours after observed consumption of leaves from an ornamental shrub later identified as wintersweet (Chimonanthus praecox). Despite symptomatic treatment, both sheep died. Three other sheep that consumed the plant died after displaying similar clinical signs, resulting in 2 deaths the prior evening and 1 recovery the next morning. Gross necropsy and histologic findings were diagnostically inconclusive. Rumen contents tested positive for the alkaloid calycanthine, a centrally-acting convulsant known to be present in wintersweet. Case reports of calycanthine toxicity in ruminants are limited, with no detailed reports published in the United States. Calycanthine has been isolated from the seeds, flowers, and leaves of the plant. Wintersweet is part of the family Calycanthaceae that including 3 species native to North America, all of which pose a neurologic risk to ruminants if consumed.

Silibinin alleviates inflammation-induced bone loss by modulating biological interaction between human gingival fibroblasts and monocytes

BACKGROUND

Silibinin has shown various pharmacological effects that could be attributed to its antioxidant, anti-inflammatory, and immunoregulatory properties. However, the therapeutic potential of silibinin for periodontitis has not been investigated.

METHODS

The therapeutic effects of silibinin in ligation-induced experimental periodontitis were investigated using biochemical, histological, and immunohistochemical methods. The effects of silibinin on the osteoclastogenesis of RAW264.7 cells were investigated using TRAP staining, quantitative polymerase chain reaction (qPCR), pit formation, and immunoblotting. Moreover, its effects on inflammatory cytokine production, RANKL expression, and oxidative stress in lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (HGFs) were evaluated using qPCR and flow cytometry. A coculture system was established to elucidate the effects of silibinin on the crosstalk between LPS-stimulated HGFs and undifferentiated monocytes.

RESULTS

Silibinin significantly reduced the alveolar bone loss, decreased the gingival inflammation and RANKL expression, and decreased the RANKL/osteoprotegerin ratio in gingival tissues in experimental periodontitis. The in vitro results showed that silibinin inhibited RANKL-induced osteoclast differentiation and function of RAW264.7 cells and suppressed RANKL-induced nuclear factor of activated T cells 1 (NFATc1) induction and translocation through the nuclear factor-κB and mitogen-activated protein kinase signaling pathways. Silibinin decreased the inflammatory cytokine level and oxidative stress production in LPS-stimulated HGFs; significantly suppressed membrane-bound RANKL expression on LPS-stimulated HGFs; and significantly disrupted TRAP+ cell differentiation in the coculture system.

CONCLUSIONS

Silibinin effectively inhibits inflammation-induced bone loss in experimental periodontitis based on the regulation of stimulated HGFs by inhibiting the expression of inflammatory and osteoclastogenic mediators. Collectively, targeting the inflamed HGF resolution that mediates osteogenesis may use silibinin as a potential drug-repurposing candidate for modulating alveolar bone destruction in periodontitis.

SUMMARY

Silibinin effectively inhibits inflammation-induced bone loss in experimental periodontitis based on the regulation of stimulated HGFs by inhibiting the expression of inflammatory and osteoclastogenic mediators.

Resolution of inflammation in oral diseases

The resolution of inflammation is an essential endogenous process that protects host tissues from an exaggerated chronic inflammatory response. Multiple interactions between host cells and resident oral microbiome regulate the protective functions that lead to inflammation in the oral cavity. Failure of appropriate regulation of inflammation can lead to chronic inflammatory diseases that result from an imbalance between pro-inflammatory and pro-resolution mediators. Thus, failure of the host to resolve inflammation can be considered an essential pathological mechanism for progression from the late stages of acute inflammation to a chronic inflammatory response. Specialized pro-resolving mediators (SPMs), which are essential polyunsaturated fatty acid (PUFA)-derived autacoid mediators, aid in regulating the endogenous inflammation resolving process by stimulating immune cell-mediated clearance of apoptotic polymorphonuclear neutrophils, cellular debris, and microbes, restricting further neutrophil tissue infiltration, and counter-regulating pro-inflammatory cytokine production. The SPM superfamily contains four specialized lipid mediator families: lipoxins, resolvins, protectins, and maresins that can activate resolution pathways. Understanding the crosstalk between resolution signals in the tissue response to injury has therapeutic application potential for preventing, maintaining, and regenerating chronically damaged tissues. Here, we discuss the fundamental concepts of resolution as an active biochemical process, novel concepts demonstrating the role of resolution mediators in tissue regeneration in periodontal and pulpal diseases, and future directions for therapeutic applications with particular emphasis on periodontal therapy.

The Periodontal Pathogen Fusobacterium nucleatum Exacerbates Alzheimer's Pathogenesis via Specific Pathways

Alzheimer's Disease (AD) is the most common form of dementia in older adults and has a devastating impact on the patient's quality of life, which creates a significant socio-economic burden for the affected individuals and their families. In recent years, studies have identified a relationship between periodontitis and AD. Periodontitis is an infectious/inflammatory disease that destroys the supporting periodontal structure leading to tooth loss. Dysbiosis of the oral microbiome plays a significant role in the onset and development of periodontitis exhibiting a shift to overgrowth of pathobionts in the normal microflora with increasing local inflammation. Fusobacterium nucleatum is a common pathogen that significantly overgrows in periodontitis and has also been linked to various systemic diseases. Earlier studies have reported that antibodies to F. nucleatum can be detected in the serum of patients with AD or cognitive impairment, but a causal relationship and a plausible mechanism linking the two diseases have not been identified. In this study, we conducted both in vivo and in vitro experiments and found that F. nucleatum activates microglial cells causing morphological changes, accelerated proliferation and enhanced expression of TNF-α and IL-1β in microglial cells. In our in vivo experiments, we found that F. nucleatum-induced periodontitis resulted in the exacerbation of Alzheimer's symptoms in 5XFAD mice including increased cognitive impairment, beta-amyloid accumulation and Tau protein phosphorylation in the mouse cerebrum. This study may suggest a possible link between a periodontal pathogen and AD and F. nucleatum could be a risk factor in the pathogenesis of AD. We are currently further identifying the pathways through which F. nucleatum modulates molecular elements in enhancing AD symptoms and signs. Data are available via ProteomeXchange with identifier PXD033147.

Does the use of omega-3 fatty acids as an adjunct to non-surgical periodontal therapy provide additional benefits in the treatment of periodontitis? A systematic review and meta-analysis

This review aimed to assess the impact of dietary omega-3 fatty acids as an adjunct to non-surgical periodontal treatment when compared with periodontal treatment alone on periodontal clinical parameters of periodontitis patients. We included only randomized clinical trials (RCTs) with at least 3-months follow-up of non-surgical periodontal therapy, in combination with dietary omega-3 fatty acids. The MEDLINE, EMBASE, and LILACS databases were searched for articles published up to October 2021. Random-effects meta-analyses were conducted to determine the change in clinical attachment level (CAL), probing pocket depth (PPD), bleeding on probing (BOP), and gingival index (GI) after therapy. Of the eight hundred eighty-four potentially relevant papers retrieved from the electronic databases, 10 RCTs were selected for qualitative analysis, and of these, 8 RCTs were included in meta-analysis. RCTs showed a significant PPD reduction/CAL gain associated with the use of omega-3 fatty acids. The pooled estimates revealed significant overall PPD reduction of 0.42 mm (95% CI 0.15, 0.68) and CAL gain 0.58 mm (95% CI 0.24, 0.92). In individuals with periodontitis, the use of omega-3 fatty acid dietary supplementation as an adjunct to non-surgical periodontal treatment can provide additional benefits in CAL gain and PPD reduction, compared with non-surgical periodontal treatment alone.

A novel adiponectin receptor agonist (AdipoAI) ameliorates type 2 diabetes-associated periodontitis by enhancing autophagy in osteoclasts

BACKGROUND AND OBJECTIVE

Type 2 diabetes (T2D)-associated periodontitis is severe and refractory in many cases. Considered an inflammatory disease, T2D predisposes to periodontitis by increasing whole-body inflammation. One mechanism of increased inflammation is thatT2D is mediated by loss of production or function of the anti-inflammatory hormone adiponectin. In our previous report, AdipoRon, an adiponectin receptor agonist, and AdipoAI, a newly discovered, more specific agonist, attenuated T2D-associated inflammation by inhibiting osteoclastogenesis and LPS-induced endotoxemia. Autophagy plays an important role during osteoclast differentiation and function. The impact of AdipoAI on osteoclast function and autophagy involved in osteoclastogenesis is not known. Here, we compare AdipoRon and AdipoAI potency, side effects and mechanism of action in T2D-associated periodontitis.

METHODS

The RAW 264.7 cell line was used for in vitro studies. We analyzed the potential cytotoxicity of AdipoAI using the CCK-8 assay. The anti-osteoclastogenic potential of AdipoAI was studied by real-time qPCR and tartrate-resistant acid phosphatase staining. The actions of AdipoAI involved in autophagy were tested by real-time qPCR, western blot and immunofluorescence staining. In the diet-induced obesity model of T2D, we investigated the impact of AdipoAI on fasting blood glucose, alveolar bone loss, and gingival inflammation in mice with experimental periodontitis.

RESULTS

AdipoRon inhibited osteoclastogenesis and AdipoAI inhibited osteoclastogenesis at lower doses than AdipoRon without any cytotoxicity. In DIO mice with experimental periodontitis, AdipoAI reduced mouse body weight in 14 days, reducing fasting glucose levels, alveolar bone destruction, osteoclast number along the alveolar bone surface, and decreased the expression of pro-inflammatory factors in periodontal tissues. AdipoAI and AdipoRon also enhanced LC3A/B expression when cultured with RANKL.3-Methyladenine, a known autophagy inhibitor, decreased LC3A/B expression and reversed the inhibition of osteoclastogenesis during AdipoAI treatment.

CONCLUSIONS

Our results demonstrate that AdipoAI ameliorates the severity of T2D-associated periodontitis by enhancing autophagy in osteoclasts at lower doses than AdipoRon without demonstrable side effects. Thus, AdipoAI has pharmaceutical potential for treating diabetes-associated periodontal disease.

Safety and Preliminary Efficacy of a Novel Host-Modulatory Therapy for Reducing Gingival Inflammation

Background

Periodontal disease is among the sixth most common inflammatory diseases worldwide with high risk to promote complications from other inflammatory diseases including diabetes, cardiovascular disease and Alzheimer’s Disease. Failure of active resolution of inflammation pathways is implicated in pathogenesis of periodontal diseases, including gingivitis. Lipoxin A4 (LXA4), a member of the specialized pro-resolving lipid mediators (SPMs) that drive resolution of inflammation via GPC-receptor mediated pathways, offered therapeutic advantages in preclinical models of periodontitis.

Methods

We conducted a randomized, placebo-controlled, parallel-group Phase 1 clinical trial to determine the safety and preliminary efficacy of an LXA4 analog in patients with gingival inflammation. One hundred twenty-seven (127) individuals were randomized to daily use of an oral rinse containing a LXA4 mimetic, methyl ester-benzo-lipoxin A4 (BLXA4), placebo rinse or a no-rinse control group for 28 days. Treatment emergent adverse events (TEAEs) were assessed for safety, the primary outcome. Secondary outcomes included the change in the level of gingival inflammation and periodontal pocket depth (PD). Serum SPMs were monitored using targeted lipid mediator lipidomics to assess potential systemic impact of BLXA4.

Results

The frequency of TEAEs was similar in BLXA4 and placebo-treated groups with no study-related SAEs. Once-daily rinsing with BLXA4 for 28-days resulted in a greater decrease in gingival inflammation compared to placebo rinse and no-rinse control groups (mean change: 0.26 GI unit vs 0.21 and 0.17, respectively). PD reduction was also greater with BLXA4 oral rinse compared to placebo and no-rinse groups (mean reduction: 1.23 mm vs. 0.71 mm and 0.46 mm, respectively). Topical application of BLXA4 increased serum levels of SPMs.

Conclusion

Treatment with BLXA4 reduces local inflammation, and increases abundance of pro-resolution molecules systemically, which may dampen inflammation that can mediate progression and course of inflammatory diseases beyond periodontitis.

Clinical Trial Registration

ClinicalTrials.gov, identifier (NCT02342691).

Identification and characterization of a novel adiponectin receptor agonist adipo anti-inflammation agonist and its anti-inflammatory effects in vitro and in vivo

BACKGROUND AND PURPOSE

Adiponectin (APN) is an adipokine secreted from adipocytes that binds to APN receptors AdipoR1 and AdipoR2 and exerts an anti-inflammatory response through mechanisms not fully understood. There is a need to develop small molecules that activate AdipoR1 and AdipoR2 and to be used to inhibit the inflammatory response in lipopolysaccharide (LPS)-induced endotoxemia and other inflammatory disorders.

EXPERIMENTAL APPROACH

We designed 10 new structural analogues of an AdipoR agonist, AdipoRon (APR), and assessed their anti-inflammatory properties. Bone marrow-derived macrophages (BMMs) and peritoneal macrophages (PEMs) were isolated from mice. Levels of pro-inflammatory cytokines were measured by reverse transcription and real-time quantitative polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA) and microarray in LPS-induced endotoxemia mice and diet-induced obesity (DIO) mice in which systemic inflammation prevails. Western blotting, immunohistochemistry (IHC), siRNA interference and immunoprecipitation were used to detect signalling pathways.

KEY RESULTS

A novel APN receptor agonist named adipo anti-inflammation agonist (AdipoAI) strongly suppresses inflammation in DIO and endotoxemia mice, as well as in cultured macrophages. We also found that AdipoAI attenuated the association of AdipoR1 and APPL1 via myeloid differentiation marker 88 (MyD88) signalling, thus inhibiting activation of nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK) and c-Maf pathways and limiting the production of pro-inflammatory cytokines in LPS-induced macrophages.

CONCLUSION AND IMPLICATIONS

AdipoAI is a promising alternative therapeutic approach to APN and APR to suppress inflammation in LPS-induced endotoxemia and other inflammatory disorders via distinct signalling pathways.

Omega-3 Fatty Acids and Low-Dose Aspirin in the Treatment of Periodontitis and Metabolic Syndrome: Case Report

AIMS

To investigate the use of ω-3 fatty acids and low-dose aspirin as adjuncts to periodontal debridement in a patient with periodontitis and metabolic syndrome.

METHODS

Periodontal and systemic parameters were assessed at baseline and 6 months. Gingival crevicular fluid was analyzed for interleukin (IL)-1β, IL-6 and interferon (IFN)-γ levels by multiplex ELISA at baseline, 3 and 6 months.

RESULTS

The treatment was effective in reducing probing depth, clinical attachment level, bleeding on probing and plaque index, and glycated hemoglobin, triglycerides IL-1β, IL-6 and IFN-γ levels over time.

CONCLUSIONS

The adjunctive use of ω-3 and low-dose aspirin to periodontal debridement might have potential benefits in the treatment of periodontitis in a patient with metabolic syndrome.

Proposal of a Clinical Endpoint for Periodontal Trials: The Treat-to-Target Approach

The selection of proper outcome measures is a critical step in clinical research. Most randomized clinical trials (RCTs) assessing the effects of initial anti-infective periodontal therapies use surrogate outcomes as primary outcome variables, such as mean changes in probing depth (PD) or in clinical attachment. However, these parameters do not reflect disease remission/control at patient level, which has led to subjective interpretations of the data from RCTs and Systematic Reviews. Based on a comprehensive analysis of 724 patients from USA, Germany and Brazil treated for periodontitis, this paper suggests that the clinical endpoint of "≤4 sites with PD≥5mm" is effective in determining disease remission/control after active periodontal treatment and therefore, may represent a pertinent endpoint for applying the treat-to-target concept in RCTs. Furthermore, regression models showed that the presence of >10% and >20% sites with bleeding on probing in the mouth post-treatment increases the risk of a patient leaving the endpoint from 1-2 years (OR=3.5 and 8.7, respectively). Researchers are encouraged to present results on this outcome when reporting their trials, as this will allow for an objective comparison across studies and facilitate systematic reviews, and consequently, the extrapolation of data from research to clinical practice.

Development and validation of a predictive model for periodontitis using NHANES 2011-2012 data

AIM

To develop and validate a predictive model for moderate-to-severe periodontitis in the adult USA population, with data from the 2011-2012 National Health and Nutrition Examination Survey (NHANES) cycle.

MATERIAL AND METHODS

A subset of 3017 subjects aged >30 years, with >14 teeth present and having received a periodontal examination in addition to data collected on cardio-metabolic risk measures (smoking habit, body mass index [BMI], blood pressure, total cholesterol and glycated haemoglobin [HbA1c]) were used for model development by multivariable logistic regression.

RESULTS

The prevalence of moderate and severe periodontitis using CDC/AAP classification was 37.1% and 13.2%, respectively. A multivariable logistic regression model revealed that HbA1c ≥5.7% was significantly associated with moderate-to-severe periodontitis (odds ratio, OR = 1.29; p < 0.01). A predictive model including age, gender, ethnicity, HbA1c and smoking habit as variables had 70.0% sensitivity and 67.6% specificity in detecting moderate-to-severe periodontitis in US adults.

CONCLUSIONS

Periodontitis is a common disease in North American adults, and its prevalence is significantly higher in individuals with pre-diabetes or diabetes. The present study demonstrates that a model including age, gender, ethnicity, HbA1c and smoking habit could be used as a reliable screening tool for periodontitis in primary medical care settings to facilitate referral of patients at risk for periodontal examination and diagnosis.

Atherosclerosis, Periodontal Disease, and Treatment with Resolvins

PURPOSE OF REVIEW

This review aims to discuss the existing evidence on the link between atherosclerosis and periodontitis by particularly presenting new findings that link the pathology and therapy of these diseases. Acute vascular ischemic events that can lead to stroke or myocardial infarction are initiated by inflammatory processes leading to rupture or erosion of plaques susceptible to thrombosis ("high risk" or "vulnerable"). These are highly inflamed plaques residing in the media and adventitia that may not be detected by angiography measurments of luminal narrowing. Statistically significant excess risk for atherosclerotic cardiovascular disease has been reported in persons with periodontitis independent of established risk factors. We hypothesized that the systemic pathologic links also represent potential therapeutic links.

RECENT FINDINGS

We recently demonstrated that periodontal inflammation promotes atherosclerotic plaque inflammation and destabilization. As discrete pathological regions, these plaques with a high susceptibility to rupture can be imaged and differentiated from lower risk plaques. In cholesterol-fed rabbits with periodontal disease, circulating inflammatory mediators were also significantly elevated thereby contributing to "vulnerable blood," a systemic characteristic of high risk for cardiovascular events. New studies show that certain lipid mediators, including lipoxins and resolvins, are potent in preventing and possibly treating a number of inflammation-associated diseases, including periodontitis and vascular inflammation. The concept of the vulnerable patient and the pro-resolving approach open new terrain for discovery of paradigm-changing therapies for the prevention and treatment of two of the most common diseases of man. Importantly, lipoxins and resolvins are natural receptor agonists that do not exhibit the same pro-atherogenic side effects attributed to anti-inflammatory medications (e.g., NSAIDs) but rather coordinate resolution of inflammation and a return to homeostasis.

Moesin: a potential LPS receptor on human monocytes

Bacterial endotoxin (lipopolysaccharide, LPS), a glycolipid found in the outer membrane of Gram-negative bacteria, induces the secretion of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-1, and IL-6 by monocytes/macrophages. The secretion of these biologically active compounds leads to multiple pathological conditions, such as septic shock. There is substantial evidence that chronic exposure to LPS in periodontal diseases mediates, at least in part, the tissue destruction associated with the Gram-negative infection. LPS receptor has been shown to be CD14, a 55 kDa protein. LPS—CD14 interactions mediate many monocyte/macrophage functions in the inflammatory response. However, CD14 lacks a cytoplasmic domain, or any known signal transduction sequence motif, suggesting the existence of another cell surface domain capable of transducing signals. More recently, significant work has implicated Toll proteins in LPS-mediated signaling. The purpose of the present work was to investigate, identify, and characterize secondary LPS binding cell surface domain(s) on monocytes/macrophages. Initial experiments with anti-CD14 blocking antibody revealed only partial blocking of the LPS induced TNF-α response. The kinetics of these experiments suggested a second, low-affinity receptor. Cross-linking experiments were performed to identify LPS binding sites. Two domains were identified: a 55 kDa protein which was inhibited by anti-CD14 (presumably the CD14 receptor) and a second 78 kDa domain. Partial protein sequencing of the 78 kDa domain using mass spectroscopic analysis ascribed this domain to Moesin (membrane organizing extension spike protein). Preliminary experiments using anti-Moesin monoclonal antibody revealed a dose-dependent blocking of LPS induced TNF-α response with a total blocking at 50 µg/ml. Irrelevant isotype controls had no effect. Additional experiments were performed to evaluate the specificity of the anti-Moesin blocking. Separate experiments evaluated anti-Moesin effects on monocyte chemotaxis, IL-1 production in response to IL-1 stimulation, and TNF-α secretion in response to Staphylococcus aureus stimulation. Anti-Moesin antibody only blocked LPS-mediated events. Histological analysis of tissue sections harvested from LPS-induced skin lesions exhibited a 3-fold reduction of the polymorphonuclear neutrophil infiltrate in Moesin-deficient mice compared to wild type mice. The data suggest that Moesin functions as an independent LPS receptor on human monocytes.

Macrophage Migration Inhibitory Factor (MIF) Supports Homing of Osteoclast Precursors to Peripheral Osteolytic Lesions

By binding to its chemokine receptor CXCR4 on osteoclast precursor cells (OCPs), it is well known that stromal cell-derived factor-1 (SDF-1) promotes the chemotactic recruitment of circulating OCPs to the homeostatic bone remodeling site. However, the engagement of circulating OCPs in pathogenic bone resorption remains to be elucidated. The present study investigated a possible chemoattractant role of macrophage migration inhibitory factor (MIF), another ligand for C-X-C chemokine receptor type 4 (CXCR4), in the recruitment of circulating OCPs to the bone lytic lesion. To accomplish this, we used Csf1r-eGFP-knock-in (KI) mice to establish an animal model of polymethylmethacrylate (PMMA) particle-induced calvarial osteolysis. In the circulating Csf1r-eGFP+ cells of healthy Csf1r-eGFP-KI mice, Csf1r+/CD11b+ cells showed a greater degree of RANKL-induced osteoclastogenesis compared to a subset of Csf1r+/RANK+ cells in vitro. Therefore, Csf1r-eGFP+/CD11b+ cells were targeted as functionally relevant OCPs in the present study. Although expression of the two cognate receptors for MIF, CXCR2 and CXCR4, was elevated on Csf1r+/CD11b+ cells, transmigration of OCPs toward recombinant MIF in vitro was facilitated by ligation with CXCR4, but not CXCR2. Meanwhile, the level of PMMA-induced bone resorption in calvaria was markedly greater in wild-type (WT) mice compared to that detected in MIF-knockout (KO) mice. Interestingly, in contrast to the elevated MIF, diminished SDF-1 was detected in a particle-induced bone lytic lesion of WT mice in conjunction with an increased number of infiltrating CXCR4+ OCPs. However, such diminished SDF-1 was not found in the PMMA-injected calvaria of MIF-KO mice. Furthermore, stimulation of osteoblasts with MIF in vitro suppressed their production of SDF-1, suggesting that MIF can downmodulate SDF-1 production in bone tissue. Systemically administered anti-MIF neutralizing monoclonal antibody (mAb) inhibited the homing of CXCR4+ OCPs, as well as bone resorption, in the PMMA-injected calvaria, while increasing locally produced SDF-1. Collectively, these data suggest that locally produced MIF in the inflammatory bone lytic site is engaged in the chemoattraction of circulating CXCR4+ OCPs. © 2016 American Society for Bone and Mineral Research.

B cells promote obesity-associated periodontitis and oral pathogen-associated inflammation (IRC3P.461)

Chronic inflammation likely underlies the predisposition of type 2 diabetes (T2D) patients to periodontitis (PD), and the exacerbation of each disease when both are present. Several lines of evidence indicate that pro-inflammatory B cells promote T2D and PD individually, but the possibility that B cells are a key link between T2D to PD is untested. We compared outcomes from oral P. gingivalis challenge of lean WT or B cell-null mice to outcomes from mice that were obese and insulin resistance prior to oral challenge. Obese WT mice responded to oral P. gingivalis challenge with significant periodontal bone loss, while obese B cell-null mice were completely protected from PD. By contrast, lean WT and B cell-null mice suffer similar periodontal bone loss in response to oral pathogen. B cells from obese/insulin resistant hosts also support oral osteoclastogenesis, and both oral and systemic production of inflammatory cytokines, including the PD-associated cytokines TNF-α and MIP-2. B cells furthermore impact adipose tissue inflammation in obese P. gingivalis-infected hosts. Taken together, these data show that fundamentally different mechanisms regulate PD in lean and obese hosts, with B cells promoting PD only if the hosts are “primed” by obesity. These results justify more intense analysis of obesity-associated changes in B cells that predispose PD in human T2D, and may indicate the use of B cell depletion to alleviate PD and T2D simultaneously.

The use of light/chemically hardened polymethylmethacrylate, polyhydroxylethylmethacrylate, and calcium hydroxide graft material in combination with polyanhydride around implants and extraction sockets in minipigs: Part II: histologic and micro-CT evaluations

BACKGROUND

This report is the second part of the previously published study on the impact of light/chemical hardening technology and a newly formulated composite graft material for crestal augmentation during immediate implant placement.

METHODS

A total of 48 implants were placed into the sockets of the mesial roots of freshly extracted mandibular premolar teeth in three minipigs. Crestal areas and intrabony spaces were randomly augmented with light-hardened graft materials including a composite graft consisting of polymethylmethacrylate, polyhydroxylethylmethacrylate, and calcium hydroxide (PPCH) plus polyanhydride (PA); PPCH graft; and PA graft, or left untreated. Distal sockets not receiving implants and the sockets of first molars (n = 60) were randomly treated with one of the graft materials or left empty. In addition, two molar sockets were treated with the original PPCH graft material. Quantitative microcomputed tomography (micro-CT) was used to assess alveolar bone structure and tissue compositions. Histologic evaluations included descriptive histology to assess the peri-implant wound healing, as well as histomorphometric measurements to determine bone-to-implant contact (BIC).

RESULTS

Both trabecular and cortical bone measurements by micro-CT did not reveal any significant differences among the groups. Sites augmented with PPCH+PA resulted in significantly greater BIC surface than PPCH alone and no-graft-treated implants (P <0.05) histologically. Stained ground sections showed complete bone formation between bone and implant surface in the PPCH+PA group, whereas sites without augmentation showed large gaps between bone and implant surfaces, indicating a slower bone apposition and less BIC surface compared to all other groups. Similar to implant sections, all materials showed positive outcome on trabecular and cortical bone formation in extraction sockets with an intact crestal cortical bone.

CONCLUSION

Histologic evaluations supported the previous findings on implant stability and function and confirmed that PPCH+PA provides a greater BIC with a well-organized implant-bone interface and is useful in crestal augmentation during immediate implant placement.

Palmitic acid and DGAT1 deficiency enhance osteoclastogenesis, while oleic acid-induced triglyceride formation prevents it

Both obesity and diabetes mellitus are associated with alterations in lipid metabolism as well as a change in bone homeostasis and osteoclastogenesis. We hypothesized that increased fatty acid levels affect bone health by altering precursor cell differentiation and osteoclast activation. Here we show that palmitic acid (PA, 16:0) enhances receptor activator of NF-κB ligand (RANKL)-stimulated osteoclastogenesis and is sufficient to induce osteoclast differentiation even in the absence of RANKL. TNFα expression is crucial for PA-induced osteoclastogenesis, as shown by increased TNFα mRNA levels in PA-treated cells and abrogation of PA-stimulated osteoclastogenesis by TNFα neutralizing antibodies. In contrast, oleic acid (OA, 18:1) does not enhance osteoclast differentiation, leads to increased intracellular triglyceride accumulation, and inhibits PA-induced osteoclastogenesis. Adenovirus-mediated expression of diacylglycerol acyl transferase 1 (DGAT1), a gene involved in triglyceride synthesis, also inhibits PA-induced osteoclastogenesis, suggesting a protective role of DGAT1 for bone health. Accordingly, Dgat1 knockout mice have larger bone marrow-derived osteoclasts and decreased bone mass indices. In line with these findings, mice on a high-fat PA-enriched diet have a greater reduction in bone mass and structure than mice on a high-fat OA-enriched diet. Thus, we propose that TNFα mediates saturated fatty acid-induced osteoclastogenesis that can be prevented by DGAT activation or supplementation with OA.

RvE1 and phagocytosis of Porphyromonas gingivalis by PMN in type 2 diabetes (P4227)

Periodontitis is a complication of Type 2 diabetes that impacts control of glycemia and systemic inflammation. Resolution of inflammation is an active, temporally orchestrated process of the biosynthesis of novel mediators (Resolvin E1, RvE1). Dysregulation of resolution may impact human inflammatory diseases such as diabetes and periodontitis. We examined the role of RvE1 in Type 2 diabetes and periodontitis by over-expressing the RvE1 receptor CMKLR1 in Type 2 diabetic mice (db-/-/db-/-); activation pathways and PMN phagocytosis of a periodontal pathogen Porphyromonas gingivalis (P.g.) were compared to wild type (WT), db-/-/db-/- and CMKLR1 over-expressing non-diabetic FVB WT. We report increased progression of periodontitis in diabetic mice is accompanied by impaired PMN phagocytosis. RvE1 enhanced phagocytosis of P.g. by WT PMN, but not PMN from diabetic animals. Phagocytosis was further increased by CMKLR1tg PMN. RvE1 rescued phagocytosis by db-/-/CMKLR1tg PMN. RvE1 induced reductions in AKT and MAPK phosphorylation that were enhanced in the transgenic animals. We conclude that PMN phagocytosis is impaired in db-/-/db-/- mice that is refractory to RvE1. RvE1 enhances PMN phagocytosis in non-diabetic WT mice and rescues impaired PMN phagocytosis in type-2 diabetic mice that over-express CMKLR1. Persistent infection and chronic inflammation characteristic of type 2 diabetes and periodontitis are due, in part, to failure of resolution of inflammation pathways.

Differential expression of salivary glycoproteins in aggressive and chronic periodontitis

OBJECTIVES

The aim of this study was to compare the pattern of secretion and the expression of mucin glycoprotein-2 (MG2) and lactoferrin in individuals with or without periodontitis.

MATERIAL AND METHODS

Five individuals with aggressive periodontitis (APG), 5 with generalized chronic periodontitis (CPG) and 5 without periodontitis (CG) were enrolled after informed consent. Non-stimulated and stimulated submandibular and sublingual saliva was collected and samples analyzed by Western blot probed with specific antibodies.

RESULTS

Stimulated and non-stimulated salivary flow rates did not differ among groups. Western blot analysis revealed that stimulation led to: an increase in MG2 expression in all groups, and to lactoferrin expression in APG and CPG. In non-stimulated saliva, CG exhibited the highest expression of both glycoproteins. In stimulated saliva, CG exhibited the highest expression of MG2, whereas APG the highest of lactoferrin.

CONCLUSIONS

The pattern of secretion of MG2 and lactoferrin in health and disease is complex. Although the present study analyzed samples from a limited number of participants, the reduced expression of MG2 and lactoferrin in APG and CPG under non-stimulated condition, the predominant circumstance of salivary secretion during the day, suggests that these salivary constituents may play a role in the etiopathogenesis of these diseases.

[Attenuation of experimental peritonitis and periodontitis in human chemokine-like receptor 1 (CMKLR1 or hChemR23) transgenic mice]

OBJECTIVE

To prepare a transgenic mouse model with myeloid-selective expression of human chemokine-like receptor 1 (CMKLR1 or hChemR23) and investigate the in vivo inflammatory response of the particular transgenic mice in induced-peritonitis and periodontitis.

METHODS

The full-length hChemR23 cDNA and hCD11b promoters were cloned into pcDNA3 plasmid. Purified transgene (2.9 kb) was used to make transgenic mice at Boston University Transgenic/Knock out Mouse Core Facility. Copy numbers and mRNA level of hChemR23 transgene in the founders were verified by Custom TaqMan Gene Expression Real-time PCR assay. Hemizygous colonies were amplified by out-breeding hChemR23 transgenic males with wide-type FVB females. Transgenic mice were injected intraperitoneally with 1 mL of zymosan A solution (1 g/L in PBS). Peritoneal lavage cells stained with PE-conjugated anti-mouse F4/80 and FITC-conjugated anti-mouse Ly6G were analyzed by FACSort. Then 9-0 silk ligature was tied around the first molar to induce a periotontitis mouse model. The distance of cementoenamel junction to the alveolar bone crest (CEJ-ABC) was calculated to evaluate the alveolar bone loss. Data were analyzed with student's t-test and variance analysis.

RESULTS

One out of the four F1 founders carried the hChemR23 transgene. hChemR23 transgenic mice had reduced 56% fewer positive labeled polymorphonuclear neutrophil (PMNs) in peritonitis abdominal lavage fluid as compared with wide-type littermates. In a ligature-induced peirodontitis mouse model, hChemR23 transgenic mice showed decreased alveolar bone loss as compared with WT littermates (P<0.05).

CONCLUSION

The hChemR23 transgenic mice over-expressed the hChemR23 at mRNA level and had reduced inflammation in the acute peritonitis and ligature-induced periodontitis model.

Inflammation-resolving mediator resolvin E1 inhibits osteoclast fusion. (169.6)

Resolution of inflammation is an active, highly coordinated process leading to the return of tissues to homeostasis. The ω-3 polyunsaturated fatty acid derivative RvE1 is a proresolving receptor agonist that has been demonstrated to protect from inflammatory bone loss by inhibiting osteoclast formation and bone resorption. It is unclear whether the actions of RvE1 in inflammatory bone disease are indirect through modulation of inflammation or the direct action of RvE1 on bone cells. Investigation of the direct impact of RvE1 treatment on the specific stages of osteoclast maturation in vitro revealed that RvE1 targets late stages of osteoclast maturation. Time-lapse vital microscopy revealed that RvE1 inhibits migration and fusion of osteoclast precursors. Western blot analysis revealed that RvE1 specifically down-regulates the pivotal osteoclast fusion protein DC-STAMP (dendritic cell specific transmembrane protein) through the leukotriene receptor BLT-1. RvE1 does not change NFATc1 induction or nuclear translocation; however, NFATc1 binding to the DC-STAMP promoter was inhibited by RvE1 treatment. The data suggest that RvE1 inhibits the binding of the transcription factor NFATc1 to the promoter of osteoclast fusion protein DC-STAMP, leading to DC-STAMP down-regulation and attenuation of osteoclast fusion. Our observations establish a dual role for inflammation resolution in innate immunity as well as bone preservation through the direct regulation of bone cell function.

Control of periodontal infections: a randomized controlled trial I. The primary outcome attachment gain and pocket depth reduction at treated sites

OBJECTIVE

To compare the treatment outcome of scaling and root planing (SRP) in combination with systemic antibiotics, local antibiotic therapy and/or periodontal surgery.

MATERIAL AND METHODS

One hundred and eighty-seven patients were assigned to eight groups treated by SRP plus none, one, two or three adjunctive treatments and monitored for 24 months in a randomized controlled clinical trial using a 2 × 2 × 2 factorial design. Systemic amoxicillin + metronidazole (SMA), local tetracycline delivery (LTC) and periodontal surgery (SURG) were evaluated as adjuncts. Changes in clinical attachment level (CAL) and probing pocket depth (PPD) were statistically evaluated by ancova of main effects.

RESULTS

Effects of adjunctive therapy to SRP were minimal at 3 months. Between 3 and 6 months PPD reduction occurred particularly in patients receiving periodontal surgery. After 6 months, both CAL gain and PPD reduction reached a plateau that was maintained at 24 months in all groups. The 24-month CAL gain was improved by SMA (0.50 mm) while PPD was reduced by SMA (0.51 mm) and SURG (0.36 mm). Smoking reduced CAL gain and PPD reduction.

CONCLUSION

Patients receiving adjunctive therapies generally exhibited improved CAL gain and/or PPD reduction when compared with the outcome of SRP alone. Only additive, not synergistic effects of the various adjunctive therapies were observed.

The use of light/chemically hardened polymethylmethacrylate, polyhydroxyethylmethacrylate, and calcium hydroxide graft material in combination with polyanhydride around implants in minipigs: part I: immediate stability and function

BACKGROUND

The present study is designed as a proof-of-concept study to evaluate light/chemical hardening technology and a newly formulated polymethylmethacrylate, polyhydroxyethylmethacrylate, and calcium hydroxide (PPCH) plus polyanhydride (PA) (PPCH-PA) composite graft material as a bone substitute compared to positive and negative controls in a minipig model.

METHODS

PPCH-PA (composite graft); PPCH alone (positive control), PA alone (positive control), and no graft (negative control) were compared. Four mandibular premolar teeth per quadrant were extracted; a total of 48 implants were placed into sockets in three minipigs. Abutments were placed protruding into the oral cavity 4 mm in height for immediate loading. Crestal areas and intrabony spaces were filled with PPCH-PA, PPCH, or PA using a three-phase delivery system in which all graft materials were hardened by a light cure. In the negative control group, implant sites were left untreated. At 12 weeks, block sections containing implants were obtained. Evaluations included periodontal probing, pullout-force load, and stability measurements to determine implant stability, radiographs to examine bone levels, and scanning electron microscopy (SEM)-energy-dispersed spectroscopy to determine bone-to-implant contact.

RESULTS

Probing measurements did not reveal any pathologic pocket formation or bone loss. Radiographs revealed that immediate implant placement and loading resulted in bone at or slightly apical to the first thread of the implant in all groups at 12 weeks. Stability test values showed a relative clinical stability for all implants (range: -7 to +1); however, implants augmented with PPCH-PA exhibited a statistically significantly greater stability compared to all other groups (P <0.05). The newly formed bone in PPCH-PA-treated sites was well organized with less marrow spaces and well-distributed osteocytes. SEM revealed a tighter implant-socket interface in the PPCH-PA group compared to other groups with reduced microfissures and implant-bone interface fractures during pullout testing, whereas implants treated with PA or no graft showed ≈ 10-μm microfissures between the implant and bone with fractures of the intrathread bone.

CONCLUSIONS

The newly formulated chemically hardened graft material PPCH-PA was useful in immediate implant placement after tooth extraction and resulted in greater stability and a well-organized implant-bone interface with immediate loading, especially in those areas where cancellous bone was present. The results of this proof-of-concept study warranted further research investigating different healing times and longer durations.

Inflammation and genetic risk indicators for early periodontitis in adults

BACKGROUND

This report is a further analysis of a study designed to determine clinical and microbial risk indicators for progressing periodontitis.

METHODS

One hundred ninety subjects who were periodontally healthy or had early signs of periodontitis (age range: 20 to 40 years) were monitored clinically at 6-month intervals followed by supragingival cleaning. At each visit, gingival crevicular fluid (GCF) and blood were collected for determination of interleukin (IL)-1β content (in GCF) and IL-1 genotype (in blood). Interproximal sites with a >1.5-mm increase in clinical attachment over 18 months were considered disease active. Characteristics were compared between active and inactive subjects.

RESULTS

IL-1β levels in GCF increased with the severity of disease and correlated well with clinical signs of incipient disease. However, the IL-1 genotype did not show any significant associations with disease or the extent of disease.

CONCLUSION

Indicators of inflammation may be important clinical determinants of future periodontal disease progression, but the IL-1 genotype was not a risk indictor for early (slight) periodontitis as defined in this subject population.

Superficial topography and porosity of an absorbable barrier membrane impacts soft tissue response in guided bone regeneration

BACKGROUND

Surface topography and porosity of barrier membranes is suggested to impact the soft and hard tissue response. In this study, the specific soft and hard tissue response characteristics of a synthetic polylactide membrane are evaluated including soft tissue inflammation, osteogenesis, and osteopromotion.

METHODS

Analysis of porosity and surface topography of the test material was performed by scanning electron microscopy. Transosseous parietal defects were surgically created bilaterally in 32 BalbC/ByJ mice and treated either with the barrier (test) or sham-operated (control). Healing was assessed histologically and histomorphometrically with quantification of bone bridging.

RESULTS

Scanning electron microscopy analyses of the barrier revealed a microstructure resembling cancellous bone. Interconnecting pores and channels, measuring between 6 and 60 microm in diameter, formed by smooth internal walls were observed throughout the device. Two distinct patterns of porosity were observed. The external surface of the membrane was characterized by a highly porous structure, with minimal interporous nodes and average pore sizes ranging between 6 and 20 microm in diameter. The internal surface was characterized by a minimal porous structure, with significant interporous nodes and average pore sizes ranging between 18 and 60 mum in diameter. Histomorphometric analyses demonstrated increased bone bridging by 60% and 300% in membrane-treated sites after 14 and 28 days of healing, respectively. The rough surface of the barrier contained significantly more giant cells, whereas the smooth surface contained significantly more inflammatory cells.

CONCLUSION

The surface topographies engineered on different sides of the barrier promote differential soft tissue responses leading, however, to similar amounts of enhanced bone formation.

Impact of clinical experience on the accuracy of probing depth measurements

OBJECTIVE

To evaluate the influence of examiner experience on the variability of periodontal probing depth measurements obtained by conventional manual probing.

METHOD AND MATERIALS

Thirty subjects with a diagnosis of chronic periodontitis were evaluated by an experienced examiner using an electronic probe and randomly assigned to 3 groups. Examiners with different levels of experience (undergraduate students, postgraduate students, and associate professors) evaluated each group with a manual probe. Electronic and conventional probing were repeated 45 days after cause-related periodontal therapy.

RESULTS

A total of 8,127 periodontal sites were evaluated at the baseline examination and reassessment. Agreement between methods was satisfactory at the baseline examination (kappa = 0.45; P < .001) and reassessment (kappa = 0.42; P < .001). The best agreement between electronic and manual probing at the baseline examination was obtained by the postgraduate students (kappa = 0.66) and at reassessment by the associate professors (kappa = 0.60). Undergraduate students obtained the lowest agreement values in both examinations (kappa = 0.42 and 0.11, respectively).

CONCLUSION

Examiner experience has direct influence on the accuracy of measurements. Dental schools must evaluate if the methodology employed to teach the use of conventional manual probing is effectively qualifying their students for dental practice.

Analgesic efficacy and tolerability of oxycodone 5 mg/ibuprofen 400 mg compared with those of oxycodone 5 mg/acetaminophen 325 mg and hydrocodone 7.5 mg/acetaminophen 500 mg in patients with moderate to severe postoperative pain: a randomized, double-blind, placebo-controlled, single-dose, parallel-group study in a dental pain model

BACKGROUND

Combination therapy has been widely used for the clinical management of acute pain. By combining 2 drugs with different mechanisms of action, such therapy provides additive analgesic effects while reducing the risk for adverse effects.

OBJECTIVE

This study compared the efficacy and tolerability of oxycodone 5 mg/ibuprofen 400 mg with those of oxycodone 5 mg/acetaminophen 325 mg, hydrocodone 7.5 mg/acetaminophen 500 mg, and placebo in a dental pain model.

METHODS

This was a multicenter, randomized, double-blind, placebo- and active-controlled, parallel-group, single-dose study in patients experiencing moderate to severe pain after surgical removal of > or = 2 ipsilateral impacted third molars. Patients were randomly assigned to receive oxycodone 5 mg/ibuprofen 400 mg, oxycodone 5 mg/acetaminophen 325 mg, hydrocodone 7.5 mg/acetaminophen 500 mg, or placebo. The primary outcome measures were total pain relief through 6 hours after dosing (TOTPAR6), sum of pain intensity differences through 6 hours (SPID6), and adverse events. Secondary efficacy measures included SPID3 and TOTPAR3, peak pain relief, peak pain intensity difference, time to onset of pain relief, time to use of rescue medication, proportion of patients reporting pain half gone, and the patient's global evaluation.

RESULTS

Two hundred forty-nine patients (43.5% male; 87.5% white; mean age, 19.1 years; mean body weight, 153.6 pounds) were randomized to treatment as follows: 62 to oxycodone 5 mg/ibuprofen 400 mg, 61 to oxycodone 5 mg/acetaminophen 325 mg, 63 to hydrocodone 7.5 mg/acetaminophen 500 mg, and 63 to placebo. Oxycodone 5 mg/ibuprofen 400 mg provided significantly greater analgesia compared with oxycodone 5 mg/acetaminophen 325 mg, hydrocodone 7.5 mg/acetaminophen 500 mg, and placebo (mean [SD] TOTPAR6, 14.98 [5.37], 9.53 [6.77], 8.36 [6.68], and 5.05 [6.49], respectively; P < 0.001, oxycodone 5 mg/ibuprofen 400 mg vs all other treatments). SPID6 values also differed significantly for oxycodone 5 mg/ibuprofen 400 mg compared with all other treatments (mean: 7.78 [4.11], 3.58 [4.64], 3.32 [4.73], and 0.69 [4.85]; P < 0.001). Oxycodone 5 mg/ibuprofen 400 mg was significantly more effective compared with the other treatments on all secondary end points (P < 0.001, all variables except peak PID vs oxycodone 5 mg/acetaminophen 325 mg [P = 0.006]), with the exception of the time to onset of analgesia. The lowest frequency of nausea and vomiting occurred in the groups that received oxycodone 5 mg/ibuprofen 400 mg (6.5% and 3.2%, respectively) and placebo (3.2% and 1.6%). Rates of nausea and vomiting were significantly lower with oxycodone 5 mg/ibuprofen 400 mg compared with oxycodone 5 mg/acetaminophen 325 mg (P = 0.011 and P = 0.009, respectively) but not with hydrocodone 7.5 mg/acetaminophen 500 mg.

CONCLUSIONS

In this study in patients with moderate to severe pain after surgery to remove impacted third molars, oxycodone 5 mg/ibuprofen 400 mg provided significantly better analgesia throughout the 6-hour study compared with the other opioid/nonopioid combinations tested, and was associated with fewer adverse events.

Clinical and other risk indicators for early periodontitis in adults

BACKGROUND

Periodontal diseases affect over half the adults in the U.S., disproportionately affecting minority populations. Periodontitis can be treated in early stages, but it is not clear what features indicate, or could be risk factors for, early stages of periodontal attachment loss. This study aimed to evaluate associations between clinical and other risk indicators of early periodontitis.

METHODS

A cross-sectional evaluation of 225 healthy and early periodontitis adults aged 20 to 40 years was performed. Clinical measurements, demographic information, and smoking histories were recorded. Analyses evaluated demographic and clinical associations with health and early periodontitis disease categories and periodontal attachment loss. Patterns of attachment loss at interproximal and buccal/lingual sites were evaluated.

RESULTS

Subject age, plaque, and measures of gingivitis exhibited associations with attachment loss and probing depth. More periodontal attachment loss was detected in African-American and Hispanic subjects compared to Asian and Caucasian subjects. Smoking history was associated with attachment loss. At interproximal sites, lower molars most frequently had attachment loss, whereas at buccal/lingual sites, higher proportions of lower bicuspid teeth demonstrated attachment loss compared with other sites.

CONCLUSIONS

In this study of subjects with minimal attachment loss, gingival inflammation was associated with early periodontitis. Lower molar interproximal sites were frequently associated with interproximal attachment loss, whereas lower bicuspid teeth were at risk for gingival recession on buccal surfaces.

Combination oxycodone 5 mg/ibuprofen 400 mg for the treatment of postoperative pain: A double-blind, placebo- and active-controlled parallel-group study

OBJECTIVE

This study compared the efficacy and safety of a single dose of oxycodone 5 mg/ibuprofen 400 mg versus its individual components and placebo in a third-molar extraction model.

METHODS

In this multicenter, double-blind, double-dummy, parallel-group investigation, subjects with moderate to severe pain within 5 hours after extraction of > or =2 ipsilateral bony impacted third molars were randomized to single doses of oxycodone 5 mg/ibuprofen 400 mg, ibuprofen 400 mg, oxycodone 5 mg, or placebo. Primary efficacy variables were the sum of pain intensity difference over 6 hours (SP1D6) and total pain relief through 6 hours (TOTPAR6). The pharmacokinetics of oxycodone and ibuprofen, alone and in combination, were also determined in a subset of patients.

RESULTS

A total of 498 subjects were randomized to treatment (187 to oxycodone 5 mg/ibuprofen 400 mg, 186 to ibuprofen 400 mg, 63 to oxycodone 5 mg, and 62 to placebo). Baseline demographics were generally similar among treatment groups, despite differences in sex (P = 0.041) and race (P = 0.023). Combination therapy was associated with greater analgesia than ibuprofen alone, oxycodone alone, or placebo (mean [SE] TOTPAR6: 13.3 [0.52], 12.2 [0.52], 4.3 [0.82], and 4.2 [0.83], respectively [P < 0.001 vs oxycodone or placebo, P = 0.012 vs ibuprofen]; mean [SE] SP1D6: 6.54 [0.42], 5.41 [0.44], 0.14 [0.60], and 0.32 [0.59], respectively [P < 0.001 vs oxycodone or placebo, P = 0.002 vs ibuprofen]). Combination therapy was well tolerated. Pharmacokinetic results implied no interaction between oxycodone and ibuprofen.

CONCLUSIONS

In this study, a single dose of oxycodone 5 mg/ibuprofen 400 mg was fast-acting, effective, and well tolerated in subjects with moderate to severe pain after dental surgery. Oxycodone 5 mg alone did not provide an efficacy benefit over placebo in this study.

A Toll-like receptor 2 ligand stimulates Th2 responses in vivo, via induction of extracellular signal-regulated kinase mitogen-activated protein kinase and c-Fos in dendritic cells

The adaptive immune system can generate distinct classes of responses, but the mechanisms that determine this are poorly understood. In this study, we demonstrate that different Toll-like receptor (TLR) ligands induce distinct dendritic cell (DC) activation and immune responses in vivo. Thus, Escherichia coli LPS (TLR-4 stimulus), activates DCs to produce abundant IL-12(p70), but little IL-10, and stimulates Th1 and Tc1 responses. In contrast, Pam-3-cys (TLR-2 stimulus) elicits less IL-12(p70), but abundant IL-10, and favors Th2 and T cytotoxic 2 (Tc2) responses. These distinct responses likely occur via differences in extracellular signal-regulated kinase signaling in DCs. Thus, Pam-3-cys induces enhanced extracellular signal-regulated kinase signaling, compared with LPS, resulting in suppressed IL-12(p70) and enhanced IL-10 production, as well as enhanced induction of the transcription factor, c-Fos. Interestingly, DCs from c-fos(-/-) mice produce more IL-12(p70), but less IL-10, compared with control DCs. Therefore, different TLR ligands induce distinct cytokines and signaling in DCs, and differentially bias Th responses in vivo.

A Multicenter Study Evaluating the Sensitization Potential of Enamel Matrix Derivative After Treatment of Two Infrabony Defects

BACKGROUND

Several studies reported some success toward regeneration in infrabony defects using enamel matrix derivative (EMD). Clinically and statistically significant improvements in probing depth reduction, clinical attachment levels, and bone fill have been demonstrated. This multi-center study evaluated the potential for sensitization to EMD in a subgroup of periodontal patients treated at least twice with at least 2 months between treatments.

METHODS

Three hundred seventy-six (376) patients in 11 university-based postgraduate periodontics programs and five private practices were selected. Surgeries were performed on infrabony defects. Following reflection of mucoperiosteal flaps and debridement of the root surface and defect, root conditioning (either citric acid pH = 1 or 24% EDTA) was performed and the site was irrigated with sterile saline. Enamel matrix derivative was reconstituted and applied to the exposed root surface and the bony defect. Flaps were sutured and pressure applied for 5 minutes. The second test defect was treated in a similar manner at least 8 weeks after the first surgery. The patient was given a diary card where any subjective adverse events (erythema, swelling, itching, headache, root hypersensitivity, or pain) were recorded at weeks 1 and 2 post-surgery. In addition, objective adverse events (gingival inflammation, ulcers, abscess, cratering, and lesions) were recorded by the investigator on an adverse event form.

RESULTS

No clinical adverse reactions to multiple applications of EMD were noted. Of 376 patients, two were referred to a dermatologist for evaluation, but neither had signs indicating any adverse events due to EMD treatment. Instead their reactions were classified as a small local abscess and tinea cruris. The single immunoassay performed (on the patient with a small local abscess) did not demonstrate any EMD-reactive antibodies, neither IgE nor IgG. Other subjective/objective reactions that occurred during this study were of the type that are commonly experienced by patients immediately following periodontal surgery, but were not related to EMD. They included headache, swelling, itching, pain, and root hypersensitivity.

CONCLUSIONS

This study demonstrated a lack of clinical adverse reactions following two separate applications of EMD. Any subjective/objective adverse reactions experienced by the patient were typical complications following routine periodontal surgery and were not directly related to the use of enamel matrix derivative.

Cutting edge: different Toll-like receptor agonists instruct dendritic cells to induce distinct Th responses via differential modulation of extracellular signal-regulated kinase-mitogen-activated protein kinase and c-Fos

Dendritic cells (DCs) are pivotal in determining the class of an adaptive immune response. However, the molecular mechanisms within DCs that determine this decision-making process are unknown. Here, we demonstrate that distinct Toll-like receptor (TLR) ligands instruct human DCs to induce distinct Th cell responses by differentially modulating mitogen-activated protein kinase signaling. Thus, Escherichia coli LPS and flagellin, which trigger TLR4 and TLR5, respectively, instruct DCs to stimulate Th1 responses via IL-12p70 production, which depends on the phosphorylation of p38 and c-Jun N-terminal kinase 1/2. In contrast, the TLR2 agonist, Pam3cys, and the Th2 stimulus, schistosome egg Ags: 1) barely induce IL-12p70; 2) stimulate sustained duration and magnitude of extracellular signal-regulated kinase 1/2 phosphorylation, which results in stabilization of the transcription factor c-Fos, a suppressor of IL-12; and 3) yield a Th2 bias. Thus, distinct TLR agonists differentially modulate extracellular signal-regulated kinase signaling, c-Fos activity, and cytokine responses in DCs to stimulate different Th responses.

p21-Activated Kinase 2 in Neutrophils Can Be Regulated by Phosphorylation at Multiple Sites and by a Variety of Protein Phosphatases

The p21-activated kinase(Pak) 2 undergoes rapid autophosphorylation/activation in neutrophils stimulated with a variety of chemoattractants (e.g., fMLP). Phosphorylation within the activation loop (Thr(402)) and inhibitory domain (Ser(141)) is known to increase the activity of Pak in vitro, whereas phosphorylation within the Nck (Ser(20)) and Pak-interacting guanine nucleotide exchange factor (Ser(192) and Ser(197)) binding sites blocks the interactions of Pak 2 with these proteins. A panel of phosphospecific Abs was used to investigate the phosphorylation of Pak 2 in neutrophils at these sites. Pak 2 underwent rapid (< or =15 s) phosphorylation at Ser(20), Ser(192/197), and Thr(402) in neutrophils stimulated with fMLP. Phosphorylation at Ser(192/197) and Thr(402) were highly transient events, whereas that at Ser(20) was more persistent. In contrast, Pak 2 was constitutively phosphorylated at Ser(141) in unstimulated neutrophils and phosphorylation at this site was less sensitive to cell stimulation than at other residues. Studies with selective inhibitors suggested that a variety of phosphatases might be involved in the rapid dephosphorylation of Pak 2 at Thr(402) in stimulated neutrophils. This was consistent with biochemical studies which showed that the activation loop of GST-Pak 3, which is homologous to that in Pak 2, was a substrate for protein phosphatase 1, 2A, and a Mg(2+)/Mn(2+)-dependent phosphatase(s) which exhibited properties different from those of the conventional isoforms of protein phosphatase 2C. The data indicate that Pak 2 undergoes a complex pattern of phosphorylation in neutrophils and that dephosphorylation at certain sites may involve multiple protein phosphatases that exhibit distinct modes of regulation.

Crown lengthening in mandibular molars: a 5-year retrospective radiographic analysis

BACKGROUND

Crown lengthening procedures are a significant part of the periodontist's armamentarium. In order to recreate the clinical space lost to caries or trauma necessary for prosthetic restoration, osseous surgery is often required. If the procedure is not carefully planned, it may result in furcation involvement of multirooted teeth.

METHODS

Twenty-six subjects with 26 mandibular molar teeth requiring crown lengthening procedures prior to prosthetic crown placement were evaluated. Nineteen subjects with 24 prosthetic crowns on lower molars which had not undergone crown lengthening were included as control teeth. Bite-wing radiographs prior to surgery (for the test group) or placement of the crown (control group) and 5 years after completion of the prosthesis were compared and analyzed.

RESULTS

Of the 26 test teeth, 10 teeth (38.5%) were found to have radiographic evidence of furcation involvement, whereas none of the control teeth developed furcation invasions.

CONCLUSION

A critical distance from the furcation (CDF) of 4 mm was established as a landmark under which, if surgery was performed on mandibular molars, chances of furcation involvement in the future were very high.

Clinical and microbial evaluation of a histatin-containing mouthrinse in humans with experimental gingivitis: a phase-2 multi-center study

OBJECTIVE

P-113, a 12 amino acid histatin-based peptide, was evaluated in a mouthrinse formulation for safety and efficacy in a phase 2 multi-center clinical study.

METHOD

294 healthy subjects abstained from oral hygiene procedures and self-administered either 0.01% P-113, 0.03% P-113 or placebo mouthrinse formulations twice daily over a 4-week treatment period. During this time, the safety, anti-gingivitis, and anti-plaque effects of P-113 were evaluated.

RESULTS

There was a significant reduction in the change from baseline to Day 22 in bleeding on probing in the 0.01% P-113 treatment group of the intent to treat population (p=0.049). Non-significant trends in the reduction of the other parameters were observed in this population (p> or =0.159). A sub-group of subjects which developed significant levels of disease within the four-week timeframe of the study was identified based on baseline gingival index scores > or =0.75. Significant findings were observed for bleeding on probing, gingival index and plaque index within this population (p<0.05). There were no treatment-related adverse events, and there were no adverse shifts in supragingival microflora during the study. Significant amounts of the peptide were retained in the oral cavity following rinsing.

CONCLUSION

These data suggest that P-113 mouthrinse is safe and reduces the development of gingival bleeding, gingivitis and plaque in the human experimental gingivitis model.