Octacalcium phosphate collagen composite for periodontal regeneration in a canine one-wall intrabony defect.

OBJECTIVE: This study aimed to evaluate the regenerative capacities of octacalcium phosphate collagen composite (OCP/Col) in one-wall intrabony defects in dogs. The background data discuss the present state of the field: No study has assessed the efficacy of OCP/Col for periodontal regeneration therapy despite the fact that OCP/Col has proved to be efficient for bone regeneration. METHODS: In six beagle dogs, the mandibular left third premolars were extracted 12 weeks before the experimental surgery. Standardized bone defects (5 mm in height and 4 mm in width) were simulated on the distal surface of the second premolars and mesially on the fourth premolars. The defect was filled with either OCP/Col (experimental group) or left empty (control group). Histological and histomorphometric characteristics were compared 8 weeks after surgery. RESULTS: No infectious or ankylotic complications were detected at any of the tested sites. The experimental group exhibited a significantly greater volume, height, and area of newly formed bone than the control group. The former also showed a greater height of the newly formed cementum than the latter, although the results were not statistically significant. The newly formed periodontal ligaments were inserted into newly formed bone and cementum in the experimental group. CONCLUSION: OCP/Col demonstrated high efficacy for bone and periodontal tissue regeneration that can be successfully applied for one-wall intrabony defects.

Diagnostic guide for immune checkpoint inhibitor-induced liver injury.

With the widespread use of immune checkpoint inhibitors (ICIs), liver injury (ICI-induced liver injury) as an immune-related adverse event has become a major concern in clinical practice. Because severe cases of liver injury require administration of corticosteroids, a comprehensive evaluation is crucial, including clinical course, blood and imaging tests, and if necessary, pathological examination through liver biopsy. As with liver injury induced by other drugs, classification of injury type by R-value is useful in deciding treatment strategies for ICI-induced liver injury. Histologically, the most representative feature is an acute hepatitis-like hepatocellular injury, characterized by diffuse lobular inflammation accompanied by CD8-positive T lymphocytes. Another condition that can cause liver injury during ICI treatment is cholangitis accompanied by non-obstructive bile duct dilatation and bile duct wall thickening. Many cases of ICI-induced cholangitis are classified as non-hepatocellular injury type, and they have been reported to respond poorly to corticosteroids. It is essential that gastroenterologists/hepatologists and doctors in various departments work in cooperation to develop a system that achieves early diagnosis and appropriate treatment of ICI-induced liver injury.

Limitations of Self-Report Tools in Pain Evaluation of Patients With Vertebral Fractures.

Few studies have evaluated the usefulness and limitations of pain assessment using verbal communication tools for acute orthopedic diseases in older patients. The purpose of this study was to assess the rate of usage of the numerical rating scale (NRS), a verbal communication tool, and to identify the characteristics of patients in whom continuous assessment was impossible. We retrospectively examined electronic medical records of patients with acute vertebral fractures who had been admitted to our hospital between April 2018 and March 2020. Continuous pain assessment using the NRS was possible in 43.2% of hospitalized patients with the fractures. The factors preventing continuous pain assessment using the NRS were an advanced age and low Mini-Mental State Examination (MMSE) scores. Based on the receiver-operating characteristic curves, the cutoff age and MMSE score were >85.3 years and <22, respectively. Continuous NRS-based pain assessment is difficult in older adult patients or those with cognitive decline with acute vertebral fractures. In future, a simple observational assessment tool for patients with dementia should be introduced in acute medical care settings.

Availability of Observational Pain Assessment Tools in Hospitalized Patients with Osteoporotic Vertebral Fractures.

Background and Objectives: Osteoporotic vertebral fractures in older patients cause lower back pain and abnormal posture, resulting in impaired activities of daily living (ADLs). Assessing pain using self-reported assessment tools is difficult, especially in patients with moderate-to-severe cognitive impairment. Recently, observational assessment tools have been used when self-reported ones were difficult to administer. No studies have reported the usefulness of observational assessment tools in patients with acute-phase orthopedic disorders without complication. This study aimed to examine the availability of observational tools for pain assessment in patients with lumbar vertebral fractures. Materials and Methods: Patients admitted to our hospital with acute-phase vertebral fractures were enrolled in this prospective observational study. Pain was assessed using Japanese versions of the Abbey pain scale and Doloplus-2 observational assessment tools, and the Numerical Rating Scale, a self-reported assessment tool. To compare the pain assessment tool, we examined whether each tool correlated with ADLs and ambulatory status. ADLs were assessed using the Barthel Index. Ambulatory status was assessed using the Functional Ambulation Categories and the 10-m walking test. Results: Similar to the Numerical Rating Scale scores, assessments with the Abbey pain scale and Doloplus-2 showed significant decreases in scores over time. A significant positive correlation was observed between the self-reported and observational assessment tools. Each pain assessment tool was significantly negatively correlated with ADLs and ambulatory status. Conclusions: When self-reported assessment with the Numerical Rating Scale is difficult for patients with cognitive impairment, pain can be estimated using the Abbey pain scale and Doloplus-2 observational assessment tools.

Histological diagnosis of polyploidy discriminates an aggressive subset of hepatocellular carcinomas with poor prognosis.

BACKGROUND: Although genome duplication, or polyploidization, is believed to drive cancer evolution and affect tumor features, its significance in hepatocellular carcinoma (HCC) is unclear. We aimed to determine the characteristics of polyploid HCCs by evaluating chromosome duplication and to discover surrogate markers to discriminate polyploid HCCs. METHODS: The ploidy in human HCC was assessed by fluorescence in situ hybridization for multiple chromosomes. Clinicopathological and expression features were compared between polyploid and near-diploid HCCs. Markers indicating polyploid HCC were explored by transcriptome analysis of cultured HCC cells. RESULTS: Polyploidy was detected in 36% (20/56) of HCCs and discriminated an aggressive subset of HCC that typically showed high serum alpha-fetoprotein, poor differentiation, and poor prognosis compared to near-diploid HCCs. Molecular subtyping revealed that polyploid HCCs highly expressed alpha-fetoprotein but did not necessarily show progenitor features. Histological examination revealed abundant polyploid giant cancer cells (PGCCs) with a distinct appearance and frequent macrotrabecular-massive architecture in polyploid HCCs. Notably, the abundance of PGCCs and overexpression of ubiquitin-conjugating enzymes 2C indicated polyploidy in HCC and efficiently predicted poor prognosis in combination. CONCLUSIONS: Histological diagnosis of polyploidy using surrogate markers discriminates an aggressive subset of HCC, apart from known HCC subgroups, and predict poor prognosis in HCC.

Income-related inequalities in the association of smoking with periodontitis: a cross-sectional analysis in Tokyo Metropolitan Districts.

OBJECTIVE: Socio-economic status (SES) and smoking are risk factors for periodontitis; however, their interaction has not been determined. We investigated the effect of modification of SES and smoking with periodontal conditions. MATERIALS AND METHODS: Data on the social background, smoking status, and dental examination of 1033 individuals residing in the Tokyo Metropolitan District were analyzed. The outcomes were the number of remaining teeth and the proportion of teeth with probing pocket depth (PPD) ≥ 4 mm and ≥ 6 mm. Multilevel linear and Poisson regression analyses were performed after adjusting for possible confounding factors, including SES, assessed by the average income of the residential area. RESULTS: The mean number of remaining teeth was 24.6 ± 4.8, and the proportion of teeth with PPD ≥ 4 mm and ≥ 6 mm was 31.2 ± 28.5% and 12.2 ± 18.1%, respectively. After adjusting for confounding factors, the lowest-income population had significantly lesser teeth (coefficient: - 0.46, 95% CI - 0.89, 0.02, p = 0.039) and a higher proportion of teeth with PPD ≥ 4 mm than the highest-income population (ratio of means: 1.22, 95% CI 1.03-1.44, p = 0.013). Significant interactions were observed; income inequalities in periodontitis were significant only among current smokers. CONCLUSION: Inequality in socio-economic status is associated with oral health inequalities. The adverse effects of smoking on periodontitis might be greater in the low-income population. CLINICAL RELEVANCE: The low-income population, especially current smokers, had significantly more compromised oral health than the high-income population. In addition to the emphasis on smoking cessation, the promotion of universal health coverage for dental care is necessary to reduce oral health inequalities.

A Novel High-Energy Vacuum Ultraviolet Light Photofunctionalization Approach for Decomposing Organic Molecules around Titanium.

Titanium undergoes biological aging, represented by increased hydrophobicity and surface accumulation of organic molecules over time, which compromises the osseointegration of dental and orthopedic implants. Here, we evaluated the efficacy of a novel UV light source, 172 nm wavelength vacuum UV (VUV), in decomposing organic molecules around titanium. Methylene blue solution used as a model organic molecule placed in a quartz ampoule with and without titanium specimens was treated with four different UV light sources: (i) ultraviolet C (UVC), (ii) high-energy UVC (HUVC), (iii) proprietary UV (PUV), and (iv) VUV. After one minute of treatment, VUV decomposed over 90% of methylene blue, while there was 3-, 3-, and 8-fold more methylene blue after the HUVC, PUV, and UVC treatments, respectively. In dose-dependency experiments, maximal methylene blue decomposition occurred after one minute of VUV treatment and after 20-30 min of UVC treatment. Rapid and effective VUV-mediated organic decomposition was not influenced by the surface topography of titanium or its alloy and even occurred in the absence of titanium, indicating only a minimal photocatalytic contribution of titanium dioxide to organic decomposition. VUV-mediated but not other light source-mediated methylene blue decomposition was proportional to its concentration. Plastic tubes significantly reduced methylene blue decomposition for all light sources. These results suggest that VUV, in synergy with quartz ampoules, mediates rapid and effective organic decomposition compared with other UV sources. This proof-of-concept study paves the way for rapid and effective VUV-powered photofunctionalization of titanium to overcome biological aging.

Influence of Surface Contaminants and Hydrocarbon Pellicle on the Results of Wettability Measurements of Titanium.

Hydrophilicity/hydrophobicity-or wettability-is a key surface characterization metric for titanium used in dental and orthopedic implants. However, the effects of hydrophilicity/hydrophobicity on biological capability remain uncertain, and the relationships between surface wettability and other surface parameters, such as topography and chemistry, are poorly understood. The objective of this study was to identify determinants of surface wettability of titanium and establish the reliability and validity of the assessment. Wettability was evaluated as the contact angle of ddH2O. The age of titanium specimens significantly affected the contact angle, with acid-etched, microrough titanium surfaces becoming superhydrophilic immediately after surface processing, hydrophobic after 7 days, and hydrorepellent after 90 days. Similar age-related loss of hydrophilicity was also confirmed on sandblasted supra-micron rough surfaces so, regardless of surface topography, titanium surfaces eventually become hydrophobic or hydrorepellent with time. On age-standardized titanium, surface roughness increased the contact angle and hydrophobicity. UV treatment of titanium regenerated the superhydrophilicity regardless of age or surface roughness, with rougher surfaces becoming more superhydrophilic than machined surfaces after UV treatment. Conditioning titanium surfaces by autoclaving increased the hydrophobicity of already-hydrophobic surfaces, whereas conditioning with 70% alcohol and hydrating with water or saline attenuated pre-existing hydrophobicity. Conversely, when titanium surfaces were superhydrophilic like UV-treated ones, autoclaving and alcohol cleaning turned the surfaces hydrorepellent and hydrophobic, respectively. UV treatment recovered hydrophilicity without exception. In conclusion, surface roughness accentuates existing wettability and can either increase or decrease the contact angle. Titanium must be age-standardized when evaluating surface wettability. Surface conditioning techniques significantly but unpredictably affect existing wettability. These implied that titanium wettability is significantly influenced by the hydrocarbon pellicle and other contaminants inevitably accumulated. UV treatment may be an effective strategy to standardize wettability by making all titanium surfaces superhydrophilic, thereby allowing the characterization of individual surface topography and chemistry parameters in future studies.

Disparity in the Influence of Implant Provisional Materials on Human Gingival Fibroblasts with Different Phases of Cell Settlement: An In Vitro Study.

The development of healthy peri-implant soft tissues is critical to achieving the esthetic and biological success of implant restorations throughout all stages of healing and tissue maturation, starting with provisionalization. The purpose of this study was to investigate the effects of eight different implant provisional materials on human gingival fibroblasts at various stages of cell settlement by examining initial cell attachment, growth, and function. Eight different specimens-bis-acrylic 1 and 2, flowable and bulk-fill composites, self-curing acrylic 1 and 2, milled acrylic, and titanium (Ti) alloy as a control-were fabricated in rectangular plates (n = 3). The condition of human gingival fibroblasts was divided into two groups: those in direct contact with test materials (contact experiment) and those in close proximity to test materials (proximity experiment). The proximity experiment was further divided into three phases: pre-settlement, early settlement, and late settlement. A cell culture insert containing each test plate was placed into a well where the cells were pre-cultured. The number of attached cells, cell proliferation, resistance to detachment, and collagen production were evaluated. In the contact experiment, bis-acrylics and composites showed detrimental effects on cells. The number of cells attached to milled acrylic and self-curing acrylic was relatively high, being approximately 70% and 20-30%, respectively, of that on Ti alloy. There was a significant difference between self-curing acrylic 1 and 2, even with the same curing modality. The cell retention ability also varied considerably among the materials. Although the detrimental effects were mitigated in the proximity experiment compared to the contact experiment, adverse effects on cell growth and collagen production remained significant during all phases of cell settlement for bis-acrylics and flowable composite. Specifically, the early settlement phase was not sufficient to significantly mitigate the material cytotoxicity. The flowable composite was consistently more cytotoxic than the bulk-fill composite. The harmful effects of the provisional materials on gingival fibroblasts vary considerably depending on the curing modality and compositions. Pre-settlement of cells mitigated the harmful effects, implying the susceptibility to material toxicity varies depending on the progress of wound healing and tissue condition. However, cell pre-settlement was not sufficient to fully restore the fibroblastic function to the normal level. Particularly, the adverse effects of bis-acrylics and flowable composite remained significant. Milled and self-curing acrylic exhibited excellent and acceptable biocompatibility, respectively, compared to other materials.

Influence of aging on periodontal regenerative therapy using enamel matrix derivative: A 3-year prospective cohort study.

AIM: To investigate the influence of chronological aging on periodontal regenerative therapy (PRT) outcomes with enamel matrix derivative (EMD). MATERIALS AND METHODS: In total, 253 intra-bony defects (151 patients) including 44 furcation involvement were prospectively investigated for 3 years after regenerative therapy with EMD by evaluating probing pocket depth (PPD), clinical attachment level (CAL), and radiographic bone defect depth (RBD). The influence of age on these outcomes was assessed using multilevel regression analyses adjusting for confounders. RESULTS: Participants' mean age was 55.9 ± 12.3 years (range: 22-85). Baseline PPD, CAL, and RBD were 6.14 ± 1.82, 7.22 ± 2.14, and 5.08 ± 2.04 mm, respectively. Significant improvement was observed with PPD reductions of 2.84 ± 1.73 and 2.87 ± 1.87 mm, CAL gains of 2.40 ± 1.87 and 2.47 ± 1.89 mm, and RBD gains of 1.76 ± 1.98 and 2.39 ± 2.41 mm at 1- and 3-year examinations, respectively. At the 1-year examination, multivariate analysis revealed a significant negative association between age and improvement in PPD and CAL (coefficients: -0.13, -0.23 mm per 10 years). However, by the 3-year examination, no significant association was noted between age and improvement in PPD, CAL, or RBD. CONCLUSION: Although the statistical difference was detected with age at 1-year examination, PRT with EMD significantly improved clinical outcomes on long-term observation, irrespective of the patient's age. CLINICAL TRIAL REGISTRATION NUMBER: UMIN000039846.

N-Acetyl Cysteine-Mediated Improvements in Dental Restorative Material Biocompatibility.

The fibroblast-rich gingival tissue is usually in contact with or adjacent to cytotoxic polymer-based dental restoration materials. The objective of this study was to determine whether the antioxidant amino acid, N-acetyl cysteine (NAC), reduces the toxicity of dental restorative materials. Human oral fibroblasts were cultured with bis-acrylic, flowable composite, bulk-fill composite, self-curing acrylic, and titanium alloy test specimens. Cellular behavior and function were analyzed on and around the materials. Impregnation of the bulk-fill composite and self-curing acrylic with NAC reduced their toxicity, improving the attachment, growth, and function of human oral fibroblasts on and around the materials. These mitigating effects were NAC dose dependent. However, NAC impregnation of the bis-acrylic and flowable composite was ineffective, with no cells attaching to nor around the materials. Although supplementing the culture medium with NAC also effectively improved fibroblast behaviors, direct impregnation of materials with NAC was more effective than supplementing the cultures. NAC-mediated improvements in fibroblast behavior were associated with reduced production of reactive oxygen species and oxidized glutathione together with increased glutathione reserves, indicating that NAC effectively directly scavenged ROS from materials and reinforced the cellular antioxidant defense system. These results establish a proof of concept of NAC-mediated improvements in biocompatibility in the selected dental restorative materials.

Effects of combined use of recombinant human fibroblast growth factor-2 and ß-tricalcium phosphate on ridge preservation in dehiscence bone defects after tooth extraction: A split-mouth study in dogs.

BACKGROUND AND OBJECTIVE: Following tooth extraction, bone resorption is especially severe in cases complicated with buccal dehiscence bone defects. To minimize this, various bone graft materials have been used for alveolar ridge preservation. This study aimed to evaluate additional effects of the concomitant use of recombinant human fibroblast growth factor-2 (rhFGF-2) with ß-tricalcium phosphate (ß-TCP) on ridge preservation in a dehiscence defect model after tooth extraction in dogs. MATERIALS AND METHODS: The maxillary first premolars of six beagle dogs were extracted and dehiscence defects of 4 × 4 × 5 mm (mesio-distal width × bucco-palatal width × depth) were created. Bilateral defects were filled with ß-TCP combined with 0.3% (w/v) rhFGF-2 (test sites) or the scaffold alone (control sites). Twelve weeks post-surgery, histologic and histometric evaluations were performed. RESULTS: Morphological measurements using micro-computed tomography revealed a significantly greater bone volume at the test sites (48.9 ± 9.06 mm3 ) than at the control sites (38.8 ± 7.24 mm3 ). Horizontal widths of the alveolar ridge at the coronal and middle position at the test sites (2.18 ± 0.71 mm, 2.93 ± 0.53 mm) were significantly greater than those at the control sites (1.47 ± 0.41 mm, 2.36 ± 0.45 mm, respectively). Regarding the histological parameters, the occupation rate of mineralized bone in the original defects was slightly higher at the test sites (44.07 ± 10.19%) than that at the control site (41.15 ± 6.56%). CONCLUSIONS: These results indicate that the adjunct use of rhFGF-2 with ß-TCP is effective for alveolar ridge preservation in fresh extraction sockets with dehiscence defects.

Association between periodontal inflammation and serum lipid profile in a healthy population: A cross-sectional study.

AIMS: The impact of periodontal inflammation on lipid metabolism is controversial. This study aimed to investigate the association between full-mouth periodontal inflammation and serum lipid levels. MATERIALS AND METHODS: In this cross-sectional study, we performed periodontal and bacteriological examinations during medical checkup on 131 subjects. The association between the periodontal inflamed surface area (PISA) and the lipid markers was analyzed by multiple linear regression, adjusting for age, sex, smoking, and body mass index. RESULTS: Overall, 118 medically healthy participants were analyzed. The proportions of none, mild, moderate, and severe periodontitis were 37.3%, 32.2%, 25.4%, and 5.1%, respectively. Multivariate analysis showed that high-density lipoprotein cholesterol was significantly higher in participants with the lowest tertile of PISA values (PISA low, coefficient: 7.94; 95% confidence interval [CI]: 1.63, 14.26, p = .01) compared to those in other tertiles (PISA high). Low-density/high-density lipoprotein cholesterol and total/high-density lipoprotein cholesterol ratios were significantly lower in the PISA-low group than the PISA-high group (coefficient: -0.26 and -0.30; 95% CI: -0.50, -0.02, and -0.59, -0.0002; p = .04 and .0498). Serum high-sensitivity C-reactive protein level, but not serum Porphyromonas gingivalis antibody titer, partly explained the association between PISA and high-density lipoprotein cholesterol. A significant interaction between female sex and PISA values toward high-density lipoprotein cholesterol level was detected. CONCLUSION: Periodontal inflammation was inversely associated with higher high-density lipoprotein cholesterol, especially in females. Elevated serum C-reactive protein partly explained this association.

Association between circulating tumor necrosis factor receptors and oral bacterium in patients receiving hemodialysis: a cross-sectional study.

BACKGROUND: High levels of tumor necrosis factor (TNF) receptors (TNFRs; TNFR1 and TNFR2), markers of inflammation, have been reported as significant predictors of mortality in hemodialysis patients. Porphyromonas gingivalis is a major pathogenic bacterium involved in periodontitis, which induces systemic inflammation. We investigated the association between the abundance of P. gingivalis in saliva and serum TNFR levels in hemodialysis patients. METHODS: A cross-sectional study was conducted on 121 hemodialysis patients visiting a clinic in the Tokyo metropolitan area. Medical interviews and examinations, comprehensive dental examinations, bacterial examinations for P. gingivalis in saliva, and measurements of circulating TNFR levels were conducted. Multiple linear regression analysis was performed to evaluate the association between the number of P. gingivalis and circulating TNFR levels. RESULTS: TNFR1 and TNFR2 were positively correlated with high-sensitivity C-reactive protein (hsCRP). Severe periodontitis was significantly associated with the number of P. gingivalis in saliva but not serum TNFR levels. The number of P. gingivalis was significantly associated with both TNFR1 and TNFR2 levels in sera after adjusting for age, sex, body mass index, smoking status, history of diabetes, prior cardiovascular disease events, serum levels of hsCRP and albumin, and severity of periodontitis [for TNFR1: coefficient 0.76, 95% confidence interval (CI) 0.14-1.37, p = 0.02; for TNFR2: coefficient 0.95, 95% CI 0.09-1.80, p = 0.03]. CONCLUSION: Circulating TNFR levels are associated with the number of P. gingivalis in saliva after adjusting for relevant clinical factors.

Presynaptic glutamatergic transmission and feedback system of oxytocinergic neurons in the hypothalamus of a rat model of adjuvant arthritis.

The neurohypophysial hormone oxytocin (OXT) is synthesized in the hypothalamic paraventricular and supraoptic nuclei. Recently, some studies have considered OXT to be important in sensory modulation and that the OXT protein is upregulated by acute and chronic nociception. However, the mechanism by which OXT is upregulated in neurons is unknown. In this study, we examined the resting membrane potentials and excitatory postsynaptic currents in OXT-ergic neurons in the paraventricular nucleus in adjuvant arthritis rat model, a model of chronic inflammation, using whole-cell patch-clamping. Transgenic rats expressing OXT and monomeric red fluorescent protein 1 (mRFP1) fusion protein to visualize the OXT-ergic neurons were used, and the OXT-mRFP1 transgenic rat model of adjuvant arthritis was developed by injection of heat-killed Mycobacterium butyricum. Furthermore, the feedback system of synthesized OXT was also examined using the OXT receptor antagonist L-368,899. We found that the resting membrane potentials and frequency of miniature excitatory postsynaptic currents and spontaneous excitatory postsynaptic currents in OXT-monomeric red fluorescent protein 1 neurons in the paraventricular nucleus were significantly increased in adjuvant arthritis rats. Furthermore, L-368,899 dose-dependently increased the frequency of miniature excitatory postsynaptic currents and spontaneous excitatory postsynaptic currents in OXT-ergic neurons. Following bath application of the GABAA receptor antagonist picrotoxin and the cannabinoid receptor 1 antagonist AM 251, L-368,899 still increased the frequency of miniature excitatory postsynaptic currents. However, following bath application of the nitric oxide synthase inhibitor Nω-Nitro-L-arginine methyl ester hydrochloride, L-368,899 did not alter the miniature excitatory postsynaptic current frequency. Thus, it is suggested that OXT-ergic neuron activity is upregulated via an increase in glutamate release, and that the upregulated OXT neurons have a feedback system with released endogenous OXT. It is possible that nitric oxide, but not GABA, may contribute to the feedback system of OXT neurons in chronic inflammation.

Calcitonin gene-related peptide potentiated the excitatory transmission and network propagation in the anterior cingulate cortex of adult mice.

The neuropeptide of calcitonin gene-related peptide (CGRP) plays critical roles in chronic pain, especially in migraine. Immunohistochemistry and in situ hybridization studies have shown that CGRP and its receptors are expressed in cortical areas including pain perception-related prefrontal anterior cingulate cortex. However, less information is available for the functional roles of CGRP in cortical regions such as the anterior cingulate cortex (ACC). Recent studies have consistently demonstrated that long-term potentiation is a key cellular mechanism for chronic pain in the ACC. In the present study, we used 64-electrode array field recording system to investigate the effect of CGRP on excitatory transmission in the ACC. We found that CGRP induced potentiation of synaptic transmission in a dose-dependently manner (1, 10, 50, and 100 nM). CGRP also recruited inactive circuit in the ACC. An application of the calcitonin receptor-like receptor antagonist CGRP8-37 blocked CGRP-induced chemical long-term potentiation and the recruitment of inactive channels. CGRP-induced long-term potentiation was also blocked by N-methyl-D-aspartate (NMDA) receptor antagonist AP-5. Consistently, the application of CGRP increased NMDA receptor-mediated excitatory postsynaptic currents. Finally, we found that CGRP-induced long-term potentiation required the activation of calcium-stimulated adenylyl cyclase subtype 1 (AC1) and protein kinase A. Genetic deletion of AC1 using AC1-/- mice, an AC1 inhibitor NB001 or a protein kinase A inhibitor KT5720, all reduced or blocked CGRP-induced potentiation. Our results provide direct evidence that CGRP may contribute to synaptic potentiation in important physiological and pathological conditions in the ACC, an AC1 inhibitor NB001 may be beneficial for the treatment of chronic headache.

Effects of matrix metalloproteinase inhibitors on N-methyl-D-aspartate receptor and contribute to long-term potentiation in the anterior cingulate cortex of adult mice.

Matrix metalloproteinases (MMPs) have been suggested to contribute to long-term potentiation, behavioral learning, and memory. In the dorsal horn of spinal cord, MMPs were reported to contribute to injury-related changes, and inhibitors of MMPs have been proposed as potential analgesics. However, it is unclear whether MMP inhibitors produce these effects by inhibiting the function of N-methyl-D-aspartate receptor (NMDAR), a key receptor for the induction of long-term potentiation. In this study, we wanted to examine if MMP inhibitors affect NMDAR-mediated excitatory postsynaptic currents in the anterior cingulate cortex of adult mice. Among different subtype inhibitors we used, we found that MMP-9 and MMP-2/9 inhibitors did not change NMDAR-mediated excitatory postsynaptic currents. However, MMP-3 and broad-spectrum MMP inhibitors reduced the NMDAR-mediated excitatory postsynaptic currents. Consistently, MMP-9 and MMP-2/9 inhibitors had no effect on NMDAR-dependent long-term potentiation, but MMP-3 and broad-spectrum MMP inhibitors inhibited the induction of long-term potentiation. Our results suggest that MMP inhibitors may produce their effects by inhibiting NMDAR functions in central synapses.

Comparison between different isoelectric points of biodegradable gelatin sponges incorporating ß-tricalcium phosphate and recombinant human fibroblast growth factor-2 for ridge augmentation: A preclinical study of saddle-type defects in dogs.

BACKGROUND AND OBJECTIVE: It is well known that recombinant human fibroblast growth factor-2 (rhFGF-2) signaling plays an important role in tissue repair and regeneration. rhFGF-2 strongly binds to acidic gelatin via ionic linkages and is gradually released upon gelatin decomposition. On the other hand, the linkage between rhFGF-2 and basic gelatin is so weak that most rhFGF-2 is rapidly released from basic gelatin by simple desorption. Gelatin/ß-tricalcium phosphate (ß-TCP) sponges, which comprise 50 wt% gelatin and 50 wt% ß-TCP in a cross-linked structure, can release rhFGF-2 gradually owing to their electrical features. In a previous study, we reported that new bone height in the test group using rhFGF-2 with acidic gelatin/ß-TCP sponges was significantly greater than that in the control group using acidic gelatin/ß-TCP sponges alone in a ridge augmentation model in dogs. However, whether these results depend on controlled release by the gelatin/ß-TCP sponges remains controversial. In this study, we evaluated the effects of controlled release by comparing acidic and basic gelatin/ß-TCP sponges with different isoelectric points (IEP) on ridge augmentation in dogs. MATERIALS AND METHODS: Twelve weeks after extraction of the maxillary second and third incisors of six dogs, critically sized saddle-type defects (8 mm length × 4 mm depth) were surgically created bilaterally 2 mm from the mesial side of the canine. Acidic gelatin/ß-TCP sponges (IEP 5.0) soaked with 0.3% rhFGF-2 were applied to the defect in the acidic group, whereas basic gelatin/ß-TCP sponges (IEP 9.0) soaked with 0.3% rhFGF-2 were applied to the defect in the basic group. Twelve weeks after surgery, biopsy specimens were obtained and subjected to microcomputed tomography (micro-CT) and histological analyses. RESULTS: New bone area detected by micro-CT analysis was significantly smaller in the basic group than in the acidic group. New bone height calculated by histologic sections was significantly lower in the basic group than in the acidic group. The total tissue height was lower in the basic group than in the acidic group. However, the differences between both sites were not significant. CONCLUSIONS: These findings suggest that in ridge augmentation of saddle-type defects, controlled release of rhFGF-2 induces notably more alveolar bone formation than does short-term application of rhFGF-2.

Histological healing after nonsurgical periodontal treatment with enamel matrix derivatives in canine experimental periodontitis.

The histological outcomes after nonsurgical periodontal treatment with enamel matrix derivatives (EMD) remain controversial. The present study evaluated periodontal wound healing after scaling and root planing (SRP) with subgingival application of EMD for treatment of experimental periodontitis. Periodontal breakdown was induced by applying silk ligatures around mandibular third and fourth premolars of six beagle dogs until radiographic bone loss progressed to approximately half of the root length. Probing pocket depth (PPD) and clinical attachment level (CAL) were proximally measured 2 weeks after ligature removal (baseline). Mesial and distal surfaces of the experimental teeth were subjected to SRP and randomized using a split-mouth design to subgingival application of EMD (test) or normal saline (control). PPD and CAL were re-evaluated at 11 weeks. Animals were sacrificed at 12 weeks for histological analyses. No significant differences were observed in PPD and CAL between both groups at baseline and at 11 weeks. Histologically, test sites exhibited a greater amount of new cementum than that did the control sites (p < 0.01). Moreover, the control sites revealed increased epithelial downgrowth compared with the test sites: (p < 0.05). On the other hand, no intergroup differences were detected in terms of bone position, connective tissue attachment, gingival recession, and planed root length. This study suggested that EMD has an increased potential to support formation of new cementum with decreased epithelial downgrowth when used as an adjunct to nonsurgical periodontal treatment.