Recombinant human MMP-2 associated with monoolein improves bone repair.

OBJECTIVE: The main objective of the present study was to investigate the possible osteostimulatory action of recombinant human matrix metalloproteinase-2 (rhMMP-2) implanted in a bone defect made in calvaria of rats, bounded to the monoolein as carrier. METHODS: Forty-four adult male Wistar rats (about 600 g body weight) underwent surgery in order to create a spherical defect in parietal bone on the right side of the median sagittal suture by using 4 mm diameter of a trephine drill. Animals were divided into three groups: no treatment (control, C), treatment with rhMMP-2 diluted in monoolein liquid crystal (rhMMP-2) and negative control with monoolein (M). The groups were divided into two experimental times, 2- and 4-weeks of experimental time. RESULTS: The rate of new-formed bone, estimated by the number of points on new-formed cancellous bone, was in enhanced rhMMP-2 group in both periods in comparison to C or M groups. CONCLUSION: There was no difference in bone neoformation between second to fourth week within groups. In the present study, monoolein alone had a negative role in the post-operative surgery, but monoolein associated with +rhMMP-2 had a positive role on releasing rhMMP-2 and enhance the rate of new-formed bone (Tab. 1, Fig. 5, Ref. 71).

NLRP12 Attenuates Inflammatory Bone Loss in Experimental Apical Periodontitis.

Apical periodontitis is an inflammatory disorder that results from the host immune response to microbial infection through the dental pulp, leading to alveolar bone destruction. The nod-like receptor 12 (NLRP12) is an atypical intracellular sensor of the NLR family that is involved in the negative regulation of several inflammatory conditions and also osteoclastogenesis. However, the role of NLRP12 in the regulation of immune response and bone loss induced by bacterial infection remains unclear. Here we investigated the development of apical periodontitis in wild-type (WT) and NLRP12 knockout (NLRP12-/-) mice by using micro-computed tomography together with histological, immunohistochemical, and molecular analyses. We found that NLRP12-/- mice are highly susceptible to apical periodontitis induced by bacterial infection, which is associated with an elevated infiltration of neutrophils and macrophages, periapical lesion extension, and alveolar bone destruction. Furthermore, NLRP12-/- mice showed a high expression of inflammatory cytokines ( Il1b, Il6, and Tnfa) and the osteoclastogenic markers ( Rankl and Acp5) in the periapical tissues. Consistent with this observation, NLRP12-/- mice showed an increased number of tartrate-resistant acid phosphatase-positive cells lining the apical periodontitis site, which was associated with augmented expression of the osteoclast effector genes, Ctsk and Mmp9. Mechanistically, NLRP12-deficient preosteoclasts showed elevated IκB-α degradation and p65 phosphorylation when stimulated with receptor activator of nuclear factor (NF)-κB ligand (RANKL). Similarly, increased IκB-α degradation was observed in the periapical tissue of NLRP12-/- mice. Furthermore, our in vitro study showed that preosteoclasts from NLRP12-/- mice exhibited higher RANKL-induced osteoclastogenesis, which was synergistically amplified by interleukin-1ß and tumor necrosis factor α (mimicking an inflammatory periapical milieu). In conclusion, our data show that NLRP12 exhibits a protective role in the periapical bone destruction by attenuating inflammation and osteoclastogenesis through negative regulation of the NF-κB pathway.

Effects of high-impact exercise on the physical properties of bones of ovariectomized rats fed to a high-protein diet.

The aim of this study was to evaluate the effects of high-impact physical exercise as a prophylactic and therapeutic means in osteopenic bones of rats submitted to ovariectomy and protein diet intake. A total of 64 Wistar rats were divided into eight groups (n = 8 each), being: OVX, ovx, standard diet and sedentary; OVXE, ovx, standard diet and jump; OVXP, ovx, high-protein diet and sedentary; and OVXEP, ovx, high-protein diet and jump; SH, sham, standard diet and sedentary; SHE, sham, standard diet and jump; SHP, sham, high-protein diet and sedentary; and SHEP, sham, high-protein diet and jump. OVX surgery consists of ovariectomy, and sham was the control surgery. The jumping protocol consisted of 20 jumps/day, 5 days/week. The bone structure was evaluated by densitometry, mechanical tests, histomorphometric, and immunohistochemical analyses. A high-protein diet resulted in increased bone mineral density (P = .049), but decreased maximal load (P = .026) and bone volume fraction (P = .023). The benefits of physical exercise were demonstrated by higher values of the maximal load in the trained groups compared to the sedentary groups (P < .001). The sham groups had decreased immunostaining of osteocalcin (P = .004) and osteopontin (P = .010) compared to ovx groups. However, the high-protein diet (P = .005) and jump exercise (P = .017) resulted in lower immunostaining of osteopontin compared to the standard diet and sedentary groups, respectively. In this experimental model, it was concluded that ovariectomy and a high-fat diet can negatively affect bone tissue and the high-impact exercise was not enough to suppress the deleterious effects caused by the protein diet and ovariectomy.

Influence of High-Fat Diet on Bone Tissue: An Experimental Study in Growing Rats.

BACKGROUND: The relationship between obesity and bone tissue remains contradictory, especially when the effect of high-fat diet is assessed in experimental models. The aim of this study was to evaluate the effects of high-fat diet on bone metabolism of growing rats. METHODS: Twenty weaned female Wistar rats were equally divided into two groups: SD (standard diet) and HFD (high-fat diet with 60 % of energy as fat). After five weeks of the two diets, the rats were euthanized, and the liver, blood and bones extracted. The liver was analysed for malondialdehyde (MDA) and reduced glutathione (GSH) concentrations. Blood was analysed by the ELISA method for osteoprotegerin (OPG) and tumour necrosis factor ligand superfamily member 11 (TNFSF11/RANKL). The bone tissue was analysed by dual-energy X-ray absorptiometry (DXA), mechanical tests, computed microtomography, histological quantitative analysis and scanning electron microscopy. The gene expressions of PPAR-γ Runx-2, RANKL and Cathepsin-K were also evaluated. RESULTS: HFD caused an increase in the MDA concentration, indicating oxidative stress. It also increased the expression of PPAR-γ, which is the gene that is related to adipocyte differentiation. There was an increase in BMD of the tibia of animals fed with the HFD, but other microstructural and mechanical properties were maintained unaltered. In addition, there were no changes in the gene expressions related to the differentiation of osteoblasts and osteoclasts, as well as no changes to the biochemical markers of bone formation and bone resorption. CONCLUSION: Liver and gene parameters are changed in response to the HFD. However, although there was an increase in BMD, the microstructure and function of the bone did not change after a 5-week HFD.

Influence of treadmill training on bone structure under osteometabolic alteration in rats subjected to high-fat diet.

Nutrition and physical training have important roles in the accumulation and maintenance of bone mass. The aim of this study was to evaluate, in ovariectomized rats (OVX), the effects of treadmill training (T) with high-fat diet (F) on weight gain and bone tissue properties with eight groups (n = 10) for 12 weeks: OVX SC (OVX, sedentary lifestyle, diet control); OVX SF; OVX TC; OVX TF; SH SC (SHAM, sedentary lifestyle, diet control); SH SF; SH TC; and SH TF. Weekly weight gain and final body composition were assessed. After euthanasia, tibiae were analyzed. The trained animals had higher body weight (P = 0.001), bone mineral density (P < 0.001), and trabecular bone (P < 0.001). The animals with a high-fat diet showed higher global fat (P < 0.001), percentage of global fat (P < 0.001) and deformation at impact (P = 0.031) and reduced tibial bone mineral content (P = 0.036). Physical training improves bone microarchitecture, without presenting an increase in impact resistance, and a high-fat diet increases body fat and impairs bone mineralization.

Matrix metalloproteinase 2 fused to GFP, expressed in E. coli, successfully tracked MMP-2 distribution in vivo.

Matrix Metalloproteinases (MMPs) participate in many physiological and pathological processes. One major limitation to a better understanding of the role MMPs play in these processes is the lack of well-characterized chimeric proteins and characterization of their fluorescence. The specialized literature has reported on few constructs bearing MMPs fused to the sequence of the green fluorescent protein (GFP), but none of the described constructs have been intended for expression in bacteria or for purification and use in vivo. This work has tested a recombinant reporter protein containing the MMP-2 catalytic domain fused to GFP in terms of purification efficiency, degradation of substrates in solution and in zymograms, kinetic activity, GFP fluorescence, and GFP fluorescence in whole animals after injection of the purified and lyophilized fluorescent protein. This work has also characterized rhMMP-2 (recombinant human MMP-2) and inactive clones and used them as negative controls in experiments employing catMMP-2/GFP and rhMMP-2. To our knowledge, this is the first study that has fully characterized a chimeric protein with the MMP-2 catalytic domain fused to GFP, that has efficiently purified such protein from bacteria in a single-step, and that has obtained an adequate chimeric protein for injection in animals and tracking of MMP-2 fate and activity in vivo.

Analysis of fracture healing in osteopenic bone caused by disuse: experimental study

Osteoporosis has become a serious global public health issue. Hence, osteoporotic fracture healing has been investigated in several previous studies because there is still controversy over the effect osteoporosis has on the healing process. The current study aimed to analyze two different periods of bone healing in normal and osteopenic rats. Sixty, 7-week-old female Wistar rats were randomly divided into four groups: unrestricted and immobilized for 2 weeks after osteotomy (OU2), suspended and immobilized for 2 weeks after osteotomy (OS2), unrestricted and immobilized for 6 weeks after osteotomy (OU6), and suspended and immobilized for 6 weeks after osteotomy (OS6). Osteotomy was performed in the middle third of the right tibia 21 days after tail suspension, when the osteopenic condition was already set. The fractured limb was then immobilized by orthosis. Tibias were collected 2 and 6 weeks after osteotomy, and were analyzed by bone densitometry, mechanical testing, and histomorphometry. Bone mineral density values from bony calluses were significantly lower in the 2-week post-osteotomy groups compared with the 6-week post-osteotomy groups (multivariate general linear model analysis, P<0.000). Similarly, the mechanical properties showed that animals had stronger bones 6 weeks after osteotomy compared with 2 weeks after osteotomy (multivariate general linear model analysis, P<0.000). Histomorphometry indicated gradual bone healing. Results showed that osteopenia did not influence the bone healing process, and that time was an independent determinant factor regardless of whether the fracture was osteopenic. This suggests that the body is able to compensate for the negative effects of suspension.

Analysis of fracture healing in osteopenic bone caused by disuse: experimental study.

Osteoporosis has become a serious global public health issue. Hence, osteoporotic fracture healing has been investigated in several previous studies because there is still controversy over the effect osteoporosis has on the healing process. The current study aimed to analyze two different periods of bone healing in normal and osteopenic rats. Sixty, 7-week-old female Wistar rats were randomly divided into four groups: unrestricted and immobilized for 2 weeks after osteotomy (OU2), suspended and immobilized for 2 weeks after osteotomy (OS2), unrestricted and immobilized for 6 weeks after osteotomy (OU6), and suspended and immobilized for 6 weeks after osteotomy (OS6). Osteotomy was performed in the middle third of the right tibia 21 days after tail suspension, when the osteopenic condition was already set. The fractured limb was then immobilized by orthosis. Tibias were collected 2 and 6 weeks after osteotomy, and were analyzed by bone densitometry, mechanical testing, and histomorphometry. Bone mineral density values from bony calluses were significantly lower in the 2-week post-osteotomy groups compared with the 6-week post-osteotomy groups (multivariate general linear model analysis, P<0.000). Similarly, the mechanical properties showed that animals had stronger bones 6 weeks after osteotomy compared with 2 weeks after osteotomy (multivariate general linear model analysis, P<0.000). Histomorphometry indicated gradual bone healing. Results showed that osteopenia did not influence the bone healing process, and that time was an independent determinant factor regardless of whether the fracture was osteopenic. This suggests that the body is able to compensate for the negative effects of suspension.

Emerging therapy in arthritis: Modulation of markers of the inflammatory process.

The induction of tolerance has been proposed as a therapeutic strategy for arthritis aiming to decrease progression of the pathology, probably by promoting suppressor mechanisms of the autoimmune response. This work aimed to confirm whether the treatment with vitamin D3 could synergize oral tolerance induced by hydrolyzed collagen peptides, in our experimental model of antigen induced arthritis in New Zealand rabbits. Clinical observation of the phenomenon indicates that simultaneous treatment with hydrolyzed collagen peptides and vitamin D3 was beneficial when compared with no treatment, for arthritic animals, and for arthritic animals that received treatment with only hydrolyzed collagen peptides or vitamin D3. Treatment with hydrolyzed collagen peptides caused diminished proinflammatory cytokine levels, an effect synergized significantly by the simultaneous treatment with vitamin D3. The anatomical-pathological studies of the animals that received both treatments simultaneously showed synovial tissues without lymphocytic and plasma cell infiltrates, and without vascular proliferation. Some of the synovial tissue of the animals of these groups showed a slight decrease in Galectin-3 expression. We propose that simultaneous oral treatment with vitamin D3 and hydrolyzed collagen peptides could increase the immunoregulatory effect on the process of previously triggered arthritis. We used articular cartilage hydrolysate and not collagen II because peptides best expose antigenic determinants that could induce oral tolerance. Oral tolerance may be considered in the design of novel alternative therapies for autoimmune disease and we have herein presented novel evidence that the simultaneous treatment with vitamin D3 may synergize this beneficial effect.

Liver DNA methylation analysis in adult female C57BL/6JxFVB mice following perinatal exposure to bisphenol A.

Bisphenol A (BPA) is a compound released from plastics and other consumer products used in everyday life. BPA exposure early in fetal development is proposed to contribute to programming of chronic diseases like obesity and diabetes, by affecting DNA methylation levels. Previously, we showed that in utero and lactational exposure of C57BL/6JxFVB hybrid mice via maternal feed using a dose range of 0-3000µg/kg body weight/day resulted in a sex-dependent altered metabolic phenotype in offspring at 23 weeks of age. The most univocal effects were observed in females, with reduced body weights and related metabolic effects associated with perinatal BPA exposure. To identify whether the effects of BPA in females are associated with changes in DNA methylation, this was analyzed in liver, which is important in energy homeostasis. Measurement of global DNA methylation did not show any changes. Genome-wide DNA methylation analysis at specific CpG sites in control and 3000µg/kg body weight/day females with the digital restriction enzyme analysis of methylation (DREAM) assay revealed potential differences, that could, however, not be confirmed by bisulfite pyrosequencing. Overall, we demonstrated that the observed altered metabolic phenotype in female offspring after maternal exposure to BPA was not detectably associated with liver DNA methylation changes. Still, other tissues may be more informative.

A phase I study of decitabine with pegylated interferon α-2b in advanced melanoma: impact on DNA methylation and lymphocyte populations.

BACKGROUND: Melanoma cell lines treated with decitabine show upregulation of cancer antigens, and interferon-α upregulates MHC Class I antigens in cancer cells, leading to enhanced T-cell recognition and T-cell mediated tumor apoptosis. We evaluated the synergy between the hypomethylating effects of decitabine and the immunomodulatory effects of interferon in a combination regimen administered to advanced melanoma patients in a phase 1 trial. METHODS: Patients with one prior systemic therapy were eligible. Using a modified 3 + 3 design, patients received escalating doses of decitabine and pegylated interferon α-2b (PEG-IFN) during every 28-day treatment cycle. Global DNA methylation was measured on days 1 and 5 of cycles 1 and 3. Cytokine profiling and quantification of T-cell subpopulations by FACS were performed at baseline and cycle 3. RESULTS: Seventeen patients were assigned to one of four dose levels. Decitabine 15 mg/m2/d + PEG-IFN 3 µg/kg was the maximum tolerated dose (MTD). Grade 3/4 cytopenias were seen across all dose levels: anemia (1), neutropenia (7), and thrombocytopenia (2). One patient remained progression-free for 37 weeks. The other 16 patients progressed at or before 12 weeks. Median overall survival was 39 weeks. Hypomethylation was seen at all dose levels. Due to treatment-induced lymphocytopenia, absolute changes in T-cell populations post-treatment were too small to be meaningfully interpreted. CONCLUSIONS: The response to this combination regimen was characterized by significant myelosuppression, particularly neutropenia. Although disappointing efficacy and slow accrual led to early closure of the trial, hypomethylation showed pharmacodynamic evidence of a therapeutic effect of decitabine at all dose levels.

Radiographical evaluation of bone quality after extraction of mandibular impacted and semi-impacted third molars.

AIM: The association between bone quality and fracture risk in the mandibular angle with the presence of impacted/semi-impacted third molars and after their extraction is controversial. This study aimed to assess mandibular bone quality in digital radiographies of patients after extraction of impacted/semi-impacted lower third molars. METHODS: A total of 130 sets of digital panoramic radiographies were selected and divided into the following three groups: Group 1 with 50 panoramic radiographies of patients with impacted/semi-impacted lower third molars, Group 2 with 30 panoramic radiographies of patients with lower third molar agenesis, and Group 3 with 50 panoramic radiographies of patients after extraction of impacted/semi-impacted lower third molars. The mandibular angular cortex was the anatomical structure used as parameter for bone quality assessment. ANOVA and Student's t test were applied for comparison between groups. RESULTS: Mandibular angular cortical width was significantly lower when the third molar was present in both genders (P<0.05). Agenesis of the third molar in women was associated with lower thickness of the mandibular cortex when compared with patients who had their third molar extracted (P<0.05). CONCLUSION: It can be concluded that the absence of impacted/semi-impacted lower third molars, was associated with a significant increase in cortical width.

Bacterial diversity of periodontal and implant-related sites detected by the DNA Checkerboard method.

The aim of this study was to compare the microbial composition of the subgingival biofilm from teeth and implant sulci in relation to contents originating from internal parts of the implant, abutment and implant prosthesis. Twenty subgingival biofilm samples from the mesial and distal aspects of each tooth/implant and 29 samples from the internal parts of titanium implants, abutments and implant prostheses were evaluated for the presence of 18 bacterial species using DNA Checkerboard and the differences between samples from teeth and implants were assessed with Pearson's correlation analysis. The periodontal and peri-implantar sulci presented significantly higher bacterial counts than the implant-related sites (p < 0.05 and p < 0.01, respectively). The highest counts were observed for Capnocytophaga gingivalis, Prevotella intermedia, P. nigrescens and P. micra. The correlation between the counts in the periodontal and peri-implantar sulci was r = 0.66 (p < 0.001). Weaker correlations between samples from the internal parts of the implants and periodontal sulcus (r = 0.49; p < 0.001) or peri-implant sulcus (r = 0.42; p < 0.001) were found. All 18 bacterial species were detected to be colonising the subgingival sulcus of teeth and implants, and implant components in the evaluated patients. Significant correlations between the microbiota were found, the strongest being between the periodontal and peri-implantar sulci.

Ageing and surface EMG activity patterns of masticatory muscles.

The purpose of this study was to evaluate the influence of age on the electromyographic activity of masticatory muscles. All volunteers were Brazilian, fully dentate (except for Group I - mixed dentition), Caucasian, aged 7-80, and divided into five groups: I (7-12 years), II (13-20 years), III (21-40 years), IV (41-60 years) and V (61-80 years). Except for Group V, which comprised nine women and eight men, all groups were equally divided with respect to gender (20 M/20 F). Surface electromyographic records of masticatory muscles were obtained at rest and during maximal voluntary contraction, right and left laterality, maximal jaw protrusion and maximal clenching in the intercuspal position. Statistically significant differences (P < 0.05) were found in all clinical conditions among the different age groups. Considerably different patterns of muscle activation were found across ages, with greater electromyographic activity in children and youth, and decreasing from adults to aged people.

Elongated styloid process and atheroma in panoramic radiography and its relationship with systemic osteoporosis and osteopenia.

UNLABELLED: Association between the presence of an elongated styloid process, vascular calcification (atheroma) and the potential risk factor for osteoporosis was studied. Presence of an elongated styloid process was found to be correlated with systemic osteoporosis and also between elongated styloid process and atheroma. INTRODUCTION: The association between the presences of an elongated styloid process and vascular calcification (atheroma) with the potential risk factor assessment for osteoporosis was studied. METHODS: Bone mineral density obtained by dual energy X-ray absorptiometry diagnosed osteopenia/osteoporosis on at least two of three sites (column, hips, and forearm) of 50 female patients. Panoramic maxillomandibular radiographs were taken and analyzed. Elongation of the styloid processes was measured and the presence of atheromas in the carotid was investigated. RESULTS: Eighty percent of the patients presented at least one side with elongated styloid process and the highest prevalence (87.5%) occurred in individuals between 60 and 69 years. Atheroma was found in four patients, three of which presented elongated styloid on at least one side and had diagnosed osteoporosis on at least two of the evaluated sites. CONCLUSIONS: Correlation was found between the elongation of the styloid process and systemic osteoporosis, and between elongated styloid process and atheroma. The method in this study might be used as part of a method for osteopenia/osteoporosis and atheroma risk assessment.

Anatomical variations of the mandibular nerve and its branches correlated to clinical situations.

AIM: The mandibular division of the trigeminal nerve is the largest of the three major divisions of the trigeminal nerve (fifth cranial nerve). In this way, many health professionals belonged to different fields are commonly evaluating patients suffering with orofacial pain and stomatognatic dysfunction associated to this structure. But, in the most cases, it is difficult to establish a correct diagnosis due to the anatomical complexity of the head and neck surfaces, especially when the focus is the trigeminal nerve. Thus, the objective of this research was to present the anatomical variations of the mandibular nerve and its branches correlated to more common clinical situations. METHODS: For this purpose, 20 human heads were anatomically dissected, so to study their structures, an external, medial and endocranial view. RESULTS: No significant variations related to ophthalmic and maxillary nerves were observed. Anatomical variations were observed in 20% of the total human heads dissected, all related to mandibular nerve and its branches: masseter, temporal, auriculotemporal and lingual. Variations in three to seven, on the number of the following nerves ramus, masseter and temporal were described. CONCLUSIONS: According to the present data using the described methodology, it was possible to conclude that anatomical variations are present in many subjects and they can explain many clinical situations that involve the stomatognathic structures.

Accurate detection of uniparental disomy and microdeletions by SNP array analysis in myelodysplastic syndromes with normal cytogenetics.

Progress in the management of patients with myelodysplastic syndromes (MDS) has been hampered by the inability to detect cytogenetic abnormalities in 40-60% of cases. We prospectively analyzed matched pairs of bone marrow and buccal cell (normal) DNA samples from 51 MDS patients by single nucleotide polymorphism (SNP) arrays, and identified somatically acquired clonal genomic abnormalities in 21 patients (41%). Among the 33 patients with normal bone marrow cell karyotypes, 5 (15%) had clonal, somatically acquired aberrations by SNP array analysis, including 4 with segmental uniparental disomies (UPD) and 1 with three separate microdeletions. Each abnormality was detected more readily in CD34+ cells than in unselected bone marrow cells. Paired analysis of bone marrow and buccal cell DNA from each patient was necessary to distinguish true clonal genomic abnormalities from inherited copy number variations and regions with apparent loss of heterozygosity. UPDs affecting chromosome 7q were identified in two patients who had a rapidly deteriorating clinical course despite a low-risk International Prognostic Scoring System score. Further studies of larger numbers of patients will be needed to determine whether 7q UPD detected by SNP array analysis will identify higher risk MDS patients at diagnosis, analogous to those with 7q cytogenetic abnormalities.

Shear-bond strength between a new format of intra-buccal acrylic bioadhesive drug delivery system and adhesive systems.

AIM: An intra-buccal acrylic bioadhesive device designated for drug programmed release that can stay adhered to dental enamel, and also on removable prosthetic restorations, with preventive and/or therapeutic purpose for a large clinical applications based on polymethyl methacrylate/methyl methacrylate/2 hydroxyethyl methacrylate (PMMA/MMA/HEMA) was developed, using the sodium fluoride as an active principle. This bioadhesive was evaluated for its shear bond strength when bonded with different adhesive systems. METHODS: Two substrates (recently extracted human teeth and acrylic prosthesis basis) were used to obtain the 96 test-specimens. Four adhesive systems (Cyanoacrylate ester, 3M Concise Enamel Bond Resin with or without previous enamel etching, MMA/HEMA or PMMA/MMA/ HEMA) were chosen for the fixation of the bioadhesives to substrate. Artificial saliva or distilled water was used as medium for maintaining the specimens until test. RESULTS: Statistical analysis showed that the interaction bioadhesives/acrylic prosthesis basis/cyanoacrylate ester adhesive was the most resistant to the physical removal by shearing. CONCLUSION: The newly rounded semi-convex format of acrylic device developed in this study presented satisfactory shear bond strength and might contribute to the comfort of intra-buccal use.