There is evidence indicating that curcumin has multiple biological activities, including anti-inflammatory properties. In vitro and in vivo studies demonstrate that curcumin may attenuate inflammation and the connective tissue destruction associated with periodontal disease. Most of these studies use systemic administration, and considering the site-specific nature of periodontal disease and also the poor pharmacodynamic properties of curcumin, we conducted this proof of principle study to assess the biological effect of the local administration of curcumin in a nanoparticle vehicle on experimental periodontal disease. We used 16 rats divided into two groups of 8 animals according to the induction of experimental periodontal disease by bilateral injections of LPS or of the vehicle control directly into the gingival tissues 3×/week for 4 weeks. The same volume of curcumin-loaded nanoparticles or of nanoparticle vehicle was injected into the same sites 2×/week. µCT analysis showed that local administration of curcumin resulted in a complete inhibition of inflammatory bone resorption and in a significant decrease of both osteoclast counts and of the inflammatory infiltrate; as well as a marked attenuation of p38 MAPK and NF-kB activation. We conclude that local administration of curcumin-loaded nanoparticles effectively inhibited inflammation and bone resorption associated with experimental periodontal disease.

BackgroundPiezosurgery is an osteotomy system used in medical and dental surgery. Many studies have proven clinical advantages of piezosurgery in terms of quality of cut, maneuverability, ease of use, and safety. However, few investigations have tested its superiority over the traditional osteotomy systems in terms of dynamics of bone healing. Therefore, the aim of this study was to evaluate the dynamics of bone healing after osteotomies with piezosurgery and to compare them with those associated to traditional bone drilling.MethodsOne hundred and ten rats were divided into two groups with 55 animals each. The animals were anesthetized and the tibiae were surgically exposed to create defects 2 mm in diameter by using piezosurgery (Piezo group) and conventional drilling (Drill group). Animals were sacrificed at 3, 7, 14, 30 and 60 days post-surgery. Bone samples were collected and processed for histological, histomorphometrical, immunohistochemical, and molecular analysis. The histological analysis was performed at all time points (n = 8) whereas the histomorphometrical analysis was performed at 7, 14, 30 and 60 days post-surgery (n = 8). The immunolabeling was performed to detect Vascular Endothelial Growth Factor (VEGF), Caspase-3 (CAS-3), Osteoprotegerin (OPG), Receptor Activator of Nuclear Factor kappa-B Ligand (RANKL), and Osteocalcin (OC) at 3, 7, and 14 days (n = 3). For the molecular analysis, animals were sacrificed at 3, 7 and 14 days, total RNA was collected, and quantification of the expression of 21 genes related to BMP signaling, Wnt signaling, inflammation, osteogenenic and apoptotic pathways was performed by qRT-PCR (n = 5).ResultsHistologically and histomorphometrically, bone healing was similar in both groups with the exception of a slightly higher amount of newly formed bone observed at 30 days after piezosurgery (p < 0.05). Immunohistochemical and qRT-PCR analyses didn’t detect significant differences in expression of all the proteins and most of the genes tested.ConclusionsBased on the results of our study we conclude that in a rat tibial bone defect model the bone healing dynamics after piezosurgery are comparable to those observed with conventional drilling.

Cancer cachexia represents a debilitating syndrome that diminishes quality of life and augments the toxicities of conventional treatments. Cancer cachexia is particularly debilitating in patients with pancreatic cancer (PC). Mechanisms responsible for cancer cachexia are under investigation and are largely derived from observations in syngeneic murine models of cancer which are limited in PC. We evaluate the effect of human PC cells on both muscle wasting and the systemic inflammatory milieu potentially contributing to PC-associated cachexia. Specifically, human PC xenografts were generated by implantation of pancreatic cancer cells, L3.6pl and PANC-1, either in the flank or orthotopically within the pancreas. Mice bearing orthotopic xenografts demonstrated significant muscle wasting and atrophy-associated gene expression changes compared to controls. Further, despite the absence of adaptive immunity, splenic tissue from orthotopically engrafted mice demonstrated elevations in several pro-inflammatory cytokines associated with cancer cachexia, including TNFα, IL1β, IL6 and KC (murine IL8 homologue), when compared to controls. Therefore, data presented here support further investigation into the complexity of cancer cachexia in PC to identify potential targets for this debilitating syndrome.

This study investigates the role of NLRP3 inflammasome and its main effector Caspase-1 in inflammation and alveolar bone resorption associated with periodontitis. Heat-killed Aggregatibacter actinomycetemcomitans (Aa) was injected 3x/week (4 weeks) into gingival tissues of wild-type (WT), Nlrp3-KO and Caspase1-KO mice. Bone resorption was measured by µCT and osteoclast number was determined by tartrate-resistant acid phosphatase (TRAP) staining. Inflammation was assessed histologically (H/E staining and immunofluorescence of CD45 and Ly6G). In vitro studies determined the influence of Nlrp3 and Caspase-1 in Rankl-induced osteoclast differentiation and activity and on LPS-induced expression of inflammation-associated genes. Bone resorption was significantly reduced in Casp1-KO but not in Nlrp3-KO mice. Casp1-KO mice had increased in osteoclast numbers, whereas the inflammatory infiltrate or on gene expression were similar to those of WT and Nlrp3-KO mice. Strikingly, osteoclasts differentiated from Nlrp3-deficient macrophages had increased resorbing activity in vitro. LPS-induced expression of Il-10, Il-12 and Tnf-α was significantly reduced in Nlrp3- and Casp1-deficient macrophages. As an inceptive study, these results suggest that Nlrp3 inflammasome does not play a significant role in inflammation and bone resorption in vivo and that Caspase-1 has a pro-resorptive role in experimental periodontal disease.

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Porphyromonas gingivalis, like other bacteria belonging to the phylum Bacteroidetes, synthesizes sphingolipids (SLs). However, their exact roles in microbial physiology and their potential role in mediating interactions with their eukaryotic host are unclear. Our working hypothesis for this study was that synthesis of SLs (host-like lipids) affords a mechanism that allows P. gingivalis to persist in homeostasis with its host. In a previous study, we deleted a gene (PG1780 in strain W83) predicted to encode a serine palmitoyl transferase (SPT)—the enzyme that catalyzes the first conserved step in the synthesis of SLs—and we determined that the mutant was unable to synthesize SLs. Here, we characterized the SPT enzyme encoded by PG1780, analyzed the impact of SPT deletion on P. gingivalis gene expression (RNA-Seq analysis), and began to define the impact of SL synthesis on its interactions with host cells. Enzymatic analysis verified that the protein encoded by PG1780 is indeed an SPT. RNA-Seq analysis determined that a lack of SL synthesis results in differential expression of extracytoplasmic function sigma factors, components of the type IX secretion system (T9SS), and CRISPR and cas genes. Our data demonstrate that when human THP1 macrophage-like cells were challenged with the wild type (W83) and the SL-null mutant (W83 ΔSPT), the SL-null strain elicited a robust inflammatory response (elevated IL-1β, IL-6, IL-10, IL-8, RANTES, and TNFα) while the response to the parent strain W83 was negligible. Interestingly, we also discovered that SLs produced by P. gingivalis can be delivered to host cells independent of cell-to-cell contact. Overall, our results support our working hypothesis that synthesis of SLs by P. gingivalis is central to its ability to manipulate the host inflammatory response, and they demonstrate the integral importance of SLs in the physiology of P. gingivalis.

This study investigated structural and functional features of apoptotic alveolar bone osteoclasts in estrogentreated rats. For this purpose, 15 female rats 22 days old were divided into three groups: Estrogen (EG), Sham (SG) and Control (CG). The rats of EG received daily intramuscular injection of estrogen for 7 days. The SG received only the oil vehicle. Maxillary fragments containing alveolar bone were removed and processed for light and transmission electron microscopy. Area (OcA) and number of nuclei (OcN) and bone resorption surface per TRAP-positive osteoclasts (BS ⁄ OC) were obtained. Vimentin, caspase-3 and MMP-9 immunoreactions, TUNEL ⁄ TRAP and MMP-9 ⁄ TUNEL combined reactions were performed. In EG, the OcA, OcN and BS ⁄ Oc were reduced. Moreover, osteoclasts showed cytoplasm immunolabelled by caspase-3 and a different pattern of vimentin expression in comparison with CG and SG. MMP-9 expression was not affected by estrogen and the TUNEL-positive osteoclasts were MMP-9-immunolabelled. In EG, ultrastructural images showed that apoptotic osteoclasts did not exhibit ruffled borders or clear zones and were shedding mononucleated portions. TRAPpositive structures containing irregular and dense chromatin were partially surrounded by fibroblast-like cells.In conclusion, the reduction in the BS ⁄ Oc may be due to reduction in OcA and OcN; these effects seem to be related to vimentin disarrangement rather than to an interference of estrogen with osteoclast MMP-9 expression. Osteoclast apoptosis involves caspase-3 activity and vimentin degradation; these cells release portions containing one apoptotic nucleus and, subsequently, undergo fragmentation, giving rise to apoptotic bodies.

NOD2 is a member of the NLR family of proteins that participate in the activation of the innate immune response. RIP2 is a downstream kinase activated by both NOD1 and NOD2. There is scarcity of information regarding the relevance of NOD2 in periodontitis, a chronic inflammatory condition characterized by inflammatory bone resorption. We used NOD2-KO and RIP2-KO mice in a model of microbial-induced periodontitis. Heat-killed Aggregatibacter actinomycetemcomitans was injected in the gingival tissues three times/wk for 4 wk. Bone resorption was assessed by μCT analysis; osteoclasts were identified by immunohistochemical staining for TRAP and inflammation was assessed using a severity score system in H/E-stained sections. In vitro studies using primary macrophages assessed the response macrophages using qPCR-based array and multi-ligand ELISA. Bone resorption and osteoclastogenesis were significantly reduced in NOD2-KO mice. Severity of inflammation was not affected. qPCR-focused arrays and multi-ligand ELISA showed that expression of pro-inflammatory mediators was reduced in NOD2- and RIP2-deficient cells. RANKL-induced osteoclastogenesis was impaired in NOD2- and RIP2-deficient macrophages. We conclude that NOD2 is important for osteoclast differentiation and inflammatory bone resorption in vivo and also for the macrophage response to Gram-negative bacteria.