60 research outputs found
Involvement of Notch signaling in the osteogenic differentiation of human mesenchymal stem cells stimulated by pulsed electromagnetic fields
Biophysical stimulation with pulsed electromagnetic fields (PEMFs), used in clinics to promote bone repair, favour osteogenic differentiation in human mesenchymal stem cells (hMSCs), however their molecular mechanisms are not clarified. Notch is a pathway regulating cell fate decisions which play a role in skeletal development. Notch signaling is initiated by binding a Notch ligand to a cell surface Notch receptor, resulting in a cleavage of receptor and releasing Notch intracellular domain which translocates to the nucleus and activates transcription of nuclear Notch target genes, such as the Hes/Hey family.The aim of this study is to establish if the known PEMF-induced osteogenic effects may occur through the modulation of Notch pathway. Bone marrow hMSCs cultured in basal condition (control) and in osteoinductive medium (OM) for 28 days were unexposed or continuously exposed to PEMFs (75 Hz, 1.5 mT) (Igea, Carpi, Italy). To block Notch pathway, the Notch inhibitor DAPT was used to treat a series of hMSCs cultured in OM. At different time points (day 1,3,7,14,21,28), osteogenic markers (alkaline phosphatase activity, osteocalcin and matrix mineralization), mRNA expression of osteogenic transcription factors (Runx2, Dlx5, Osterix) as well as of Notch receptors (Notch1-4), their ligands (Jagged1, Dll1 and Dll4) and nuclear target genes (Hey1, Hey2, Hes1, Hes5) were analysed.Our results showed that osteogenic markers and transcription factors increased in OM compared to control and they were further stimulated by PEMFs. Notably, PEMFs significantly increased the expression of Notch4, Dll4, Hey1, Hes1 and Hes5 in the middle phase of differentiation in OM compared to control. In the presence of DAPT, osteogenic markers as well Hes1 and Hes5 expression were significantly inhibited, in unexposed and PEMF-exposed hMSCs. Hey1 was not inhibited by DAPT suggesting a possible regulation by other signaling pathway.These new findings show that PEMFs favor osteogenic differentiation acting through Notch pathway, adding important knowledge concerning the molecular mechanisms by which PEMFs can modulate osteogenesis. This work was supported by grants from IGEA, Carpi, Italy
Electromagnetic fields counteract IL-1β during chondrogenesis in synovial bovine mesenchymal progenitor cells
Objective. Mesenchymal stem cells (MSCs) isolated from synovium and from synovial fluid, have shown a chondrogenesis potential suggesting that synovium is an excellent source of MSCs for cartilage regeneration. Electromagnetic fields (EMFs) display several effects on cartilage: increase the synthesis of proteoglycans (PGs), prevents the catabolic effect of the pro-inflammatory cytokine interleukin-1β (IL-1β), appear useful for the treatment of osteoarthritis. Our goal was to evaluate if the chondrogenic differentiation of synovial bovine mesenchymal progenitor cells, may be influenced by EMFs. Further, as chondrogenic differentiation of MSCs could be altered in an inflammatory environment and EMFs can counteract IL-1β activity, we also evaluated the role of EMFs during chondrogenic differentiation in the presence of IL-1β. Design. Synovial fluid was aspirated from the metacarpophalangeal joints of bovine. Synovial cells at the 3rd passage were centrifuged to obtain pellet cultures. Pellets were cultured in chondrogenic medium alone (control) or supplemented with 10 ng/ml TGF-β3 and/or 50 ng/ml IL-1β. The pellets were unexposed or exposed to EMF (75 Hz, 1.5 mT) (Igea, Carpi, Italy), during the whole period in culture (34 days). Alcian blue for sulphated glycosaminoglycans and immunostaining for type II collagen, were performed. PG synthesis was measured by radioactive 35S-sulphate incorporation. Results. Pellets cultured in the presence of TGF-β3 exhibited positive staining for type II collagen and Alcian blue, compared to control, indicating chondrogenic differentiation of synovial bovine mesenchymal progenitor cells. In the presence of IL-1β, type II collagen and Alcian blue staining dramatically decreased compared to TGF-β3 treatment alone. When pellets treated with both TGF-β3 and IL-1β were exposed to EMF, the histochemical staining for type II collagen and Alcian blue increased compared to EMF-unexposed pellets, suggesting that EMF might counteract the IL-1β effect. Biochemical analysis on PG synthesis confirmed histochemical data. Conclusions. The presence of inflammatory cytokines, such as IL-1β in human joints, may explain why existing methods of cartilage engineering repair strategies, that rely on the in situ differentiation of MSCs, fail to provide a reliably successful. Results of this study support the hypothesis that EMF treatment may favour chondrogenic differentiation in inflammatory conditions, suggesting a possible strategy for improving the clinical outcome of cartilage repair procedures
Electromagnetic fields (EMFs) and adenosine receptors modulate prostaglandin E2 and cytokine production in human osteoarthritic synovial fibroblasts
Objective. Synovial fibroblasts (SFs) contribute to the development of osteoarthritis (OA) by the secretion of a wide range of pro-inflammatory mediators, including cytokines and lipid mediators of inflammation (1). Previous studies show that electromagnetic fields (EMFs) may represent a potential therapeutical approach to limit cartilage degradation and to control inflammation associated to OA, and that they may act through the adenosine pathway (2). On this basis the aim of this study was to investigate if EMFs might modulate inflammatory activities of human SFs derived from OA patients (OASFs) and the possible involvement of adenosine receptors (ARs) in mediating EMF effects. Design. SFs obtained from OA patients, undergoing total hip joint replacement surgery, were exposed to EMFs (1.5 mT; 75 Hz) for 24 hours. In control and EMF-exposed cells, ARs were evaluated by western blotting, quantitative real-time RT-PCR and saturation binding experiments and cAMP levels were measured by a specific assay. In the absence and in the presence of interleukin-1β (IL-1β), used as a pro-inflammatory stimulus, prostaglandin E2 (PGE2), cytokine and matrix degrading enzyme production was evaluated in OASFs exposed to EMFs and treated with selective adenosine receptor agonists and antagonists. Results. EMF exposure induced a selective increase in A2A and A3 ARs. These increases were associated to changes in cAMP levels, indicating that ARs were functionally active in EMF-exposed cells. In IL-1β-treated OASFs, functional data obtained in the presence of A2A and A3 adenosine agonists and antagonists showed that EMFs inhibit the release of (PGE2) and of the proinflammatory cytokines interleukin-6 (IL-6) and interleukin-8 (IL-8), whilst stimulate the release of interleukin-10 (IL-10), an antinflammatory cytokine. Further, results show that these effects appear to be mediated by the EMF-induced upregulation of A2A and A3 ARs. No effects of EMFs or ARs have been observed on matrix degrading enzymes production. Conclusions: EMFs display anti-inflammatory effects in human OASFs and these EMF-induced .ffects are in part mediated by the adenosine pathway, specifically by the A2A and A3 ARs activation. Taken together, these results suggest that SFs could represent potential therapeutic targets cells for EMF treatment and open new clinical perspectives to the control of inflammation associated to joint diseases. 1. Martel-Pelletier J et al. Eklem Hastalik Cerrahisi. 2010; 21(1):2-14. 2. De Mattei M et al. Osteoarthritis Cartilage. 2009; 17(2):252-262
Effect of electrode distance in grid electrode: Numerical models and in vitro tests
Electrochemotherapy is an emerging local treatment for the management of superficial tumors and, among these, also chest wall recurrences from breast cancer. Generally, the treatment of this peculiar type of tumor requires the coverage of large skin areas. In these cases, electrochemotherapy treatment by means of standard small size needle electrodes (an array of 0.73 cm spaced needles, which covers an area of 1.5 cm2) is time-consuming and can allow an inhomogeneous coverage of the target area. We have previously designed grid devices suitable for treating an area ranging from 12 to 200 cm2. In this study, we propose different approaches to study advantages and drawbacks of a grid device with needles positioned 2 cm apart. The described approach includes a numerical evaluation to estimate electric field intensity, followed by an experimental quantification of electroporation on a cell culture. The electric field generated in a conductive medium has been studied by means of 3-dimensional numerical models with varying needle pair distance from 1 to 2 cm. In particular, the electric field evaluation shows that the electric field intensity with varying needle distance is comparable in the area in the middle of the 2 electrodes. Differently, near needles, the electric field intensity increases with the increasing electrode distance and supply voltage. The computational results have been correlated with experimental ones obtained in vitro on cell culture. In particular, electroporation effect has been assessed on human breast cancer cell line MCF7, cultured in monolayer. The use of 2-cm distant needles, supplied by 2000 V, produced an electroporation effect in the whole area comprised between the electrodes. Areas of cell culture where reversible and irreversible electroporation occurred were identified under microscope by using fluorescent dyes. The coupling of computation and experimental results could be helpful to evaluate the effect of the needle distance on the electric field intensity in cell cultures in terms of reversible or irreversible electroporation
A simplified post preparation technique after Thermafil obturation: evaluation of apical microleakage and presence of voids using methylene blue dye penetration
To evaluate the apical microleakage of Thermafil obturations after three different post space preparation techniques. Materials and methods: 33 root canals of
monoradiculated extracted teeth were prepared with M two and then obturated with Thermafil. Teeth so treated were then divided into three groups and the post space to middle root was prepared using three different techniques. In samples in group A the housing for the post was created using a Torpan bur, and the carrier was partially removed only in the coronal portion. In samples in group B the carrier was completely removed and gutta-percha was hand compacted, before canal preparation using a Torpan bur. In samples in group C the carrier was completely removed, without gutta-percha compaction, before canal preparation using Torpan bur. The roots were immersed for 72 hours in methylene blue dye solution and sectioned transversaly at 1-3-5 mm from the apex for evaluation of dye penetration using a stereomicroscope. The data collected were processed using Win CAD software and subjected to statistical analysis using the Student t test for p<0.05. Results: There were no significant differences between the three groups, except for the presence of voids in the intermediation section of teeth in groups B and C. Conclusions: Post space preparation did not influence the apical seal, and gutta-percha without voids was always found in the last millimetre of the canal obturation. This study proposes a post preparation technique which provides for complete carrier removal using pliers, hand compaction of residual gutta-percha with a manual plugger and anlargement of the root canal, using appropriate post space burs, free of any interference from the carrier. Operating time is reduced, as is the risk of creating ledges or iatrogenic perforations
Silica dioxide colloidal solutions is efficient in the treatment of chronic periodontitis: a case control study
The objective of this study was to compare the efficacy of supportive periodontal therapy (i.e. scaling and rooth planning, SRP) alone versus a chemical device silica dioxide (SiO2) colloidal solutions (SDCS) used in association with SRP in the treatment of chronic periodontitis in adult patients. A total of 20 patients with a diagnosis of chronic periodontitis (40 localized chronic periodontitis sites) in the age group of 35 to 55 were selected. None of these patients have previously received any surgical or non-surgical periodontal therapy and demonstrated radiographic evidence of moderate bone loss. Two non-adjacent sites in separate quadrants were selected in each patient to monitorize treatment efficacy (split mouth design). Clinical pocket depth (PD) and microbial analysis (MA) were analyzed at baseline and 15th day. SPSS program and paired simple statistic T-test were used to detect significant differences. Total bacteria loading, Tannerella Forsitia and Treponema Denticola loading were statistically reduced when SiO2 is locally delivered. SDCS gel is an adjuvant therapy which should be added to SRP in the management of moderate to severe chronic periodontitis
Why patients with cardiovascular risk should go to dentist: is there sufficient evidence of influence of periodontal therapy on cardiovascular disease?
Cardiovascular disease (CVD) is a common cause of death, representing 29% of the mortality
all over the word. More than 70 million Americans have been diagnosed with various forms of CVD, including high blood pressure, coronary artery disease (acute myocardial infarction and angina pectoris), disorders of peripheral arteries. There is strong evidence that periodontal disease (PD) is associated with an increased risk of CVD. In addition, many patients with CVD are also affected by PD, which can be mild or severe. The aim of this manuscript is to investigate the effects of periodontal therapy on the management of CVD. Thirty-four randomised controlled trials and reviews were included in this manuscript to test the effects of different periodontal therapies for patients with CVD. In conclusion, we may affirm that there is some lack of knowledge on the relationship between PD and CVD, however there
is sufficient evidence to justify a periodontal treatment to prevent CVD; in fact, PD is very prevalent in the middle-aged population and can have a significant impact on the cardiovascular function
Implant surface activates fibroblasts: an in vitro study
Titanium (Ti) is that the most generally used material for dental, orthopedic and maxillofacial purposes thanks to its excellent biocompatibility and mechanical properties. Several data suggest that prosthesis anchorage to bone and soft tissue are often modulated by surface characteristics. Fibroblasts are the soft tissues cells concerned in producing extracellular matrix and collagen and their tight connection to implant neck is of paramount importance in preventing peri-implant infection. The aim of this work is to grow Human Fibroblast (HFb) for seven days in wells containing (or not) dental implants. The expression levels of some adhesion and traction-resistance related genes (COL11A1, COL2A1, COL9A1, DSP, ELN, HAS1, and TFRC) were analyzed using Polymerase Chain Reaction. Our results demonstrated that several genes encoding for extracellular matrix proteins are activated so giving more insight to the comprehension of the mechanism of cell to surface adhesion
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