Effect of Enamel Matrix Derivatives on Osteoclast Formation from PBMC of Periodontitis Patients and Healthy Individuals after Interaction with Activated Endothelial Cells.

Background and objectives: Enamel matrix derivative (EMD) is produced from developing porcine tooth buds and represents a complex of low-molecular-weight hydrophobic enamel proteins. EMD is widely applied in periodontal regeneration. Osteoclasts are multinuclear cells, which are responsible for bone resorption. The precursors of osteoclasts, hematopoietic cells, undergo in vivo the process of transendothelial migration before differentiation. EMD is known to affect the process of osteoclastogenesis, but its effect on human osteoclasts precursors after the interaction with activated endothelium was never studied. Materials and Methods: Human umbilical vein endothelial cells (HUVECs)s were seeded in transwell inserts with a pore size of 8 µm and pre-activated by TNF-α and IL-1ß for 18 h. Peripheral blood mononuclear cells (PBMCs), freshly isolated from 16 periodontitis patients and 16 healthy individuals, were added to pre-activated HUVECs. Adherent, non-adherent and transmigrated cells were collected and differentiated to osteoclasts by the standard protocol in the presence or absence of EMD. The number of osteoclasts was determined by tartrate-resistant acid phosphatase staining. Results: PBMCs isolated from periodontitis patients have formed a significantly higher osteoclast number compared to PBMCs isolated from healthy individuals (p < 0.05). EMD induced concentration-dependent inhibition of osteoclast formation from PBMCs. This was true for the different PBMC fractions isolated from both healthy individuals and periodontitis patients. Conclusions: Our data show that EMD inhibits the formation and activity of osteoclasts differentiated from the progenitor cells after the interaction with activated endothelium. This might be associated with bone resorption inhibition and supporting bone regeneration in the frame of periodontal therapy.

The effect of antiresorptive drugs on implant therapy: Systematic review and meta-analysis.

OBJECTIVES: A considerable portion of the adult population has received and/or is receiving treatment with antiresorptive drugs (ARDs). It is thus relevant to assess possible side effects of ARD intake in connection to various aspects of implant therapy. The aim of this study was to answer the focused question "In patients with systemic intake of ARDs, what is the outcome and complication rate of implant therapy including associated bone grafting procedures comparing to patients without systemic intake of ARDs?" MATERIALS AND METHODS: Original studies fulfilled predefined inclusion criteria (e.g., case series, cohort studies, case-control studies, and controlled and/or randomized controlled clinical trials; retro- or prospective design; and ≥10 patients with systemic intake of ARDs). Various patient-, medication-, and intervention-related parameters [i.e., implant loss, grafting procedure complication/failure, peri-implant marginal bone levels/loss, medication-related osteonecrosis of the jaws (MRONJ), and peri-implantitis] were extracted, and meta-analyses and quality assessment were performed. RESULTS: Twenty-four studies with bisphosphonate (BP) intake (mainly low dose for osteoporosis treatment) and seven studies on hormone replacement therapy (HRT), including ≥10 patients, and controls not taking the medication were identified. Furthermore, seven studies on MRONJ associated with implants were included. Meta-analyses based on four studies reporting on patient level and eight studies reporting on implant level showed no significant differences in terms of implant loss between patients on BPs (mainly low dose for osteoporosis treatment) and controls. Furthermore, low-dose BP intake did not compromise peri-implant marginal bone levels. Based on two studies, no negative effect of HRT was observed on the implant level, while HRT appeared to exert a marginally significant negative effect regarding implant survival on the patient level and regarding peri-implant marginal bone levels. Based on six studies reporting single-patient data, MRONJ in patients on BP for osteoporosis appeared in 70% of the cases >36 months after start of drug intake, while in patients with cancer, MRONJ appeared in 64% of the cases ≤36 months after first BP intake. CONCLUSION: Low-dose oral BP intake for osteoporosis treatment, in general, does not compromise implant therapy, that is, patients on ARDs do not lose more implants nor get more implant-related complications/failures comparing to implant patients without BP intake. There is almost no information available on the possible effect on implant therapy of high-dose BPs or other widely used ARDs (e.g., denosumab), or on the success or safety of bone grafting procedures. Patients with high-dose ARD intake for management of malignancies, patients on oral BP over a longer period of time, and patients with comorbidities should be considered as high-risk patients for MRONJ.

Particle Radiation Side-Effects: Intestinal Microbiota Composition Shapes Interferon-γ-Induced Osteo-Immunogenicity.

Microbiota can both negatively and positively impact radiation-induced bone loss. Our prior research showed that compared to mice with conventional gut microbiota (CM), mice with restricted gut microbiota (RM) reduced inflammatory tumor necrosis factor (TNF) in bone marrow, interleukin (IL)-17 in blood, and chemokine (C-C motif) ligand 20 (CCL20) in bone marrow under anti-IL-17 treatment. We showed that Muribaculum intestinale was more abundant in intestinal epithelial cells (IECs) from the small intestine of female RM mice and positively associated with augmented skeletal bone structure. Female C57BL/6J pun RM mice, which were injected with anti-IL-17 antibody one day before exposure to 1.5 Gy 28Si ions of 850 MeV/u, showed high trabecular numbers in tibiae at 6 weeks postirradiation. Irradiated CM mice were investigated for lower interferon-γ and IL-17 levels in the small intestine than RM mice. IL-17 blockage resulted in bacterial indicator phylotypes being different between both microbiota groups before and after irradiation. Analysis of the fecal bacteria were performed in relation to bone quality and body weight, showing reduced tibia cortical thickness in irradiated CM mice (-15%) vs. irradiated RM mice (-9.2%). Correlation analyses identified relationships among trabecular bone parameters (TRI-BV/TV, Tb.N, Tb.Th, Tb.Sp) and Bacteroides massiliensis, Muribaculum sp. and Prevotella denticola. Turicibacter sp. was found directly correlated with trabecular separation in anti-IL-17 treated mice, whereas an unidentified Bacteroidetes correlated with trabecular thickness in anti-IL-17 neutralized and radiation-exposed mice. We demonstrated radiation-induced osteolytic damage to correlate with bacterial indicator phylotypes of the intestinal microbiota composition, and these relationships were determined from the previously discovered dose-dependent particle radiation effects on cell proliferation in bone tissue. New translational approaches were designed to investigate dynamic changes of gut microbiota in correlation with conditions of treatment and disease as well as mechanisms of systemic side-effects in radiotherapy.

Bone turnover markers in serum but not in saliva correlate with bone mineral density.

Saliva was proposed as a diagnostic tool for systemic diseases. Here we determined the correlation of bone turnover markers in saliva, bone turnover markers in serum and bone mineral density in postmenopausal osteoporotic and healthy women. Forty postmenopausal osteoporotic and 40 age-matched healthy non-osteoporotic females were recruited for this case-control study. Serum and stimulated saliva levels of osteocalcin, N-terminal propeptide of type I collagen, bone-specific alkaline phosphatase and cross-linked-C-telopeptide of type I collagen were determined. Bone mineral density of the lumbar spine, proximal femur, and total hip were obtained. We show that osteocalcin and cross-linked-C-telopeptide of type I collagen (CTX) reached detectable levels in saliva while N-terminal propeptide of type I collagen and alkaline phosphatase were close or below the detection limit. Serum levels of bone turnover markers were significantly higher than saliva levels. Correlation analysis revealed a strong correlation of serum osteocalcin and, to a lesser extent, also serum CTX values with bone mineral density in lumbar spine, femoral neck, or total hip, respectively. There was, however, no significant correlation of bone mineral density with the respective bone turnover markers in saliva. There was a trend that saliva osteocalcin correlates with femoral neck (p = 0.16) or total hip (p = 0.06). There was also no association between serum and saliva bone turnover markers. This study reveals that saliva cannot replace the withdrawal of serum to evaluate bone metabolism.

Characterization of Bone Lesions in Myeloma Before and During Anticancer Therapy Using 18F-FDG-PET/CT and 18F-NaF-PET/CT.

BACKGROUND: The objective of this study was to characterize tumor activity and mineralization status in newly-detected multiple myeloma (MM) bone lesions using 2-18F-fluoro-2-deoxy-D-glucose (18F-FDG)-PET/CT and 18F-sodium fluoride (18F-NaF)-PET/CT before and after antitumor treatment. MATERIALS AND METHODS: In this retrospective study, seven patients with histologically-verified MM were included (four women, three men; median age=57 years, standard deviation=11.23 years). PET/CT was performed with 18F-FDG and with 18F-NaF, both at baseline and after treatment. All patients had positive scans. Volumes of interest (VOIs) were drawn over all 18F-FDG-PET/CT-positive bone lesions, as well as the corresponding regions in 18F-NaF-PET/CT. For characterization of bone lesions, semi-quantitative standard uptake value (SUV) parameters were measured. RESULTS: 18F-FDG-PET/CT in the seven patients detected 39 metabolically active lesions that were correlated with the corresponding sites in 18F-fluoride-PET/CT. Overall, the lesions showed a response to therapy, with a significant decrease in SUVmax on PET/CT using 18F-FDG (p<0.001) and with 18F-NaF (p<0.001). In four patients with a second follow-up scan (at a median of 17 months after baseline scan), there was no significant change in lesion uptake. CONCLUSION: Based on our data, antitumor therapy in MM reduces not only tumor activity, but also the mineralization status of bone lesions. A second follow-up scan in a subset of the cohort yielded no change in mineralization status.

Morphometric analysis of sinus depth in the posterior maxilla and proposal of a novel classification.

The aim of this study was to analyse the posterior maxillary sinus based on its extension into the alveolar process and to provide a simple clinical classification. A retrospective cohort study was conducted in CT scans of 200 dentate and 200 edentulous patients (100 women and 100 men, respectively). After manual placement of 12 reference points morphometric analysis was performed and sinus depth, residual alveolar ridge height (RH) and the sinus opening angle were calculated. Sinuses were classified according to the quartiles of sinus depth: class I (above the hard palate), class II (0-6 mm below the hard palate) and class III (>6 mm below the hard palate). Sinus depth was found to be a reliable anatomical landmark and did not vary significantly between gender (p = 0.8940) or dentition groups (p = 0.9723). Alveolar height varied significantly between sinus classes (p < 2 × 10-16) and dentition groups (p < 2 × 10-16) but not between genders (p = 0.5178). The sinus opening angle was significantly different between sinus classes (p < 2.2 × 10-16) but not between gender or dentition groups. We propose a novel classification built upon the quartiles of sinus depth, dividing the sinuses into three classes. Our classification is the first one that represents the anatomy of the patient independent of gender and dentition.

Osteonecrosis of the jaws and bisphosphonate treatment in cancer patients.

PURPOSE: Osteonecrosis of the jaws is described as an intraoral complication after administration of intravenous nitrogen-containing bisphosphonates. In a retrospective study, patients with osteonecrosis of the jaws after bisphosphonate treatment were evaluated with regard to diagnostic investigations and therapeutic management. PATIENTS AND METHODS: Seventeen patients with osteonecrosis of the jaws after bisphosphonate treatment who were referred to our department between July 2004 and June 2005 were included in this study. Computer tomography, magnetic resonance imaging, scintigraphy, bacteriology and biopsy were used in diagnostic evaluation. All patients were treated surgically. RESULTS: The reasons for bisphosphonate treatment were multiple myeloma in 12 patients, breast cancer with bone metastasis in four patients and histiocytosis X in one patient. Five patients had received intravenous pamidronate and 12 patients zoledronic acid. The median number of treatment cycles for pamidronate was 36 times (range 4-100) in 38 months (range 4-100). Zolendric acid was given 23.5 times (range 5-39) in 26 months (range 5-39). Nine patients had a lesion in the mandible, eight in the maxilla. Clinical symptoms were exposed bone, pain and local inflammation of the mucosa. Computer tomography showed sclerotic areas in the osteonecrosis zone. The biopsy did not show a metastatic lesion. Sequestrectomy and decortication was adequate in the follow-up. CONCLUSION: Nitrogen-containing bisphosphonates appear to be associated with the risk of developing osteonecrosis of the jaws. To reduce this risk, patients should be evaluated by a dentist before beginning treatment with intravenous bisphosphonates.

Functional analysis of SPECC1L in craniofacial development and oblique facial cleft pathogenesis.

BACKGROUND: Oblique facial clefts, also known as Tessier clefts, are severe orofacial clefts, the genetic basis of which is poorly understood. Human genetics studies revealed that disruption in SPECC1L resulted in oblique facial clefts, demonstrating that oblique facial cleft malformation has a genetic basis. An important step toward innovation in treatment of oblique facial clefts would be improved understanding of its genetic pathogenesis. The authors exploit the zebrafish model to elucidate the function of SPECC1L by studying its homolog, specc1lb. METHODS: Gene and protein expression analysis was carried out by reverse-transcriptase polymerase chain reaction and immunohistochemistry staining. Morpholino knockdown, mRNA rescue, lineage tracing and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assays were performed for functional analysis. RESULTS: Expression of specc1lb was detected in epithelia juxtaposed to chondrocytes. Knockdown of specc1lb resulted in bilateral clefts between median and lateral elements of the ethmoid plate, structures analogous to the frontonasal process and the paired maxillary processes. Lineage tracing analysis revealed that cranial neural crest cells contributing to the frontonasal prominence failed to integrate with the maxillary prominence populations. Cells contributing to lower jaw structures were able to migrate to their destined pharyngeal segment but failed to converge to form mandibular elements. CONCLUSIONS: These results demonstrate that specc1lb is required for integration of frontonasal and maxillary elements and convergence of mandibular prominences. The authors confirm the role of SPECC1L in orofacial cleft pathogenesis in the first animal model of Tessier cleft, providing morphogenetic insight into the mechanisms of normal craniofacial development and oblique facial cleft pathogenesis.