91 research outputs found
A combination of methotrexate and zoledronic acid prevents bone erosions and systemic bone mass loss in collagen induced arthritis
Introduction Osteoclasts play a key role in the pathogenesis of
bone erosion and systemic bone mass loss during rheumatoid
arthritis (RA). In this study, we aimed to determine the effect of
methotrexate (MTX) and zoledronic acid (ZA), used alone or in
combination, on osteoclast-mediated bone erosions and
systemic bone mass loss in a rat model of collagen induced
arthritis (CIA). We hypothesized that MTX and ZA could have an
additive effect to prevent both bone erosion and systemic bone
loss.
Methods Arthritis was induced in 64 female Sprague-Dawley
rats. After the clinical onset of CIA, rats were assigned to
treatment with MTX (1 mg/kg/week), ZA (100 ÎŒg/kg twice
weekly), both treatments at the same regimens, or vehicle.
Arthritis score and paw thickness were recorded twice weekly.
The rats were sacrificed on D28 and hind paws were removed
for radiographic, histological and immunohistochemical
analysis. The effects of treatments on osteoclastogenesis were
determined by Tartrate resistant acid phosphatase (TRAP)
staining. Micro-CT of the tibia was carried out for
histomorphometric analysis. Bone mass density was evaluated
by densitometry.
Results MTX significantly decreased the severity of CIA,
whereas ZA slightly exacerbated it. When these two drugs were
used in combination, MTX prevented the pro-inflammatory effect
of ZA. The combination of ZA with MTX was more effective than
MTX alone for reducing structural joint damage with a dramatic
decrease of osteoclasts' number in the eroded joints. However,
MTX alone also significantly reduced the number of osteoclasts
and the number of CD68+ mononuclear cells. ZA alone, or ZA
with MTX, significantly increased the systemic bone mass
density measured by densitometry and bone volume on
histomorphometric analysis.
Conclusions A combination of MTX and ZA prevented both
bone erosion and systemic bone loss in a rat model of arthritis.
Both treatments independently decreased the number of
osteoclasts in the eroded joint. However, while MTX probably
acts mainly through a decrease of inflammation, ZA has a direct
effect on osteoclasts, allowing a dramatic down-regulation of
these cells in inflamed joints. These two different mechanisms of
action provide support for the use of a combination of these two
drugs to improve the prevention of structural joint damage in RA
Identification and verification of heat shock protein 60 as a potential serum marker for colorectal cancer
Colorectal cancer (CRC) is a major public health issue worldwide, and novel tumor markers may contribute to its efficient management by helping in early detection, prognosis or surveillance of disease. The aim of our study was to identify new serum biomarkers for CRC, and we followed a phased biomarker discovery and validation process to obtain an accurate preliminary assessment of potential clinical utility. We compared colonic tumors and matched normal tissue from 15 CRC patients, using two-dimensional difference gel electrophoresis (2D-DIGE), and identified 17 proteins that had significant differential expression. These results were further confirmed by western blotting for heat shock protein (HSP) 60, glutathione-S-transferase Pi, α-enolase, T-complex protein 1 subunit ÎČ, and leukocyte elastase inhibitor, and by immunohistochemistry for HSP60. Using mAbs raised against HSP60, we developed a reliable (precision of 5â15%) and sensitive (0.3 ng·mLâ1) immunoassay for the detection of HSP60 in serum. Elevated levels of HSP60 were found in serum from CRC patients in two independent cohorts; the receiver-operating characteristic curve obtained in 112 patients with CRC and 90 healthy controls had an area under the curve (AUC) of 0.70, which was identical to the AUC of carcinoembryonic antigen. Combination of serum markers improved clinical performance: the AUC of a three-marker logistic regression model combining HSP60, carcinoembryonic antigen and carbohydrate antigen 19-9 reached 0.77. Serum HSP60 appeared to be more specific for late-stage CRC; therefore, future studies should evaluate its utility for determining prognosis or monitoring therapy rather than early detection
Analysis of gap junctional intercellular communications using a dielectrophoresis-based microchip
Gap junctions are transmembrane structures that directly connect the cytoplasm of adjacent
cells, making intercellular communications possible. It has been shown that the behaviour of
several tumours â such as bone tumours â is related to gap junction intercellular
communications (GJIC). Several methodologies are available for studying GJIC, based on
measuring different parameters that are useful for multiple applications, such as the study of
carcinogenesis for example. These methods nevertheless have several limitations. The present
manuscript describes the setting up of a DEP-based lab-on-a-chip platform for the real-time
study of Gap Junctional Intercellular Communication between osteosarcoma cells and the
main cells accessible to their microenvironment. We conclude that using the DEParray
technology for the GJIC assessment has several advantages comparing to current techniques.
This methodology is less harmful for cells integrity; cells can be recovered after interaction to
make further molecular analysis; it is possible to study GJIC in real time; we can promote cell
interactions using up to five different populations. The setting up of this new methodology
overcomes several difficulties to perform experiments for solving questions about GJIC
process that we are not able to do with current technics
Inhibition of BET proteins and epigenetic signaling as a potential treatment for osteoporosis
International audienceHistone modifications are important for maintaining the transcription program. BET proteins, an important class of " histone reading proteins " , have recently been described as essential in bone biology. This study presents the therapeutic opportunity of BET protein inhibition in osteoporosis. We find that the pharmacological BET protein inhibitor JQ1 rescues pathologic bone loss in a post-ovariectomy osteoporosis model by increasing the trabecular bone volume and restoring mechanical properties. The BET protein inhibition suppresses osteoclast differentiation and activity as well as the osteoblastogenesis in vitro. Moreover, we show that treated non-resorbing osteoclasts could still activate osteoblast differentiation. In addition, specific inhibition of BRD4 using RNA interference inhibits osteoclast differentiation but strongly activates osteoblast mineralization activity. Mechanistically, JQ1 inhibits expression of the master osteoclast transcription factor NFATc1 and the transcription factor of osteoblast Runx2. These findings strongly support that targeting epigenetic chromatin regulators such as BET proteins may offer a promising alternative for the treatment of bone-related disorders such as osteoporosis
Severe Compromise of Preosteoblasts in a Surgical Mouse Model of Bisphosphonate-Associated Osteonecrosis of the Jaw.
Objectives: The effect of amino-bisphosphonates on osteoblastic lineage and its potential
contribution to the pathogenesis of bisphosphonate-associated osteonecrosis of the jaw
(BONJ) remain controversial. We assessed the effects of zoledronic acid (ZOL) on bone and
vascular cells of the alveolar socket using a mouse model of BONJ.
Material and Methods: Thirty-two mice were treated twice a week with either 100 ÎŒg/kg of
ZOL or saline for 12 weeks. The first left maxillary molar was extracted at the third week.
Alveolar sockets were assessed at both 3 weeks (intermediate) and 9 weeks (long-term) after
molar extraction by semi-quantitative histomorphometry for empty lacunae, preosteoblasts
(Osterix), osteoclasts (TRAP), and pericyte-like cells (CD146). Also, the bone
microarchitecture was assessed by micro-CT.
Results: Osteonecrotic-like lesions were observed in 21% of mice. Moreover, a decreased
number of preosteoblasts contrasted with the increased number of osteoclasts at both time
points. In addition, osteoclasts display multinucleation and detachment from the endosteal
surface. Furthermore, the number of pericyte-like cells increased at the intermediate time
point. The alveolar bone mass increased exclusively with long-term ZOL treatment.
Conclusion: The severe imbalance between bone-forming cells and bone-resorbing cells
showed in this study could contribute to the pathogenesis of BONJ
Factor VIII-von Willebrand Factor Complex Inhibits Osteoclastogenesis and Controls Cell Survival
Factor VIII-von Willebrand factor (FVIII·vWF) complex, a molecule involved in coagulation, can be physically associated with osteoprotegerin (OPG). OPG is an anti-osteoclastic protein and a soluble receptor for the proapoptotic protein TRAIL (tumor necrosis factor-related apoptosis-inducing ligand), suggesting a potential role of FVIII·vWF complex in bone and cancer biology. We, thus, assessed the effects of FVIII·vWF complex on osteoclastogenesis and cell survival. We first evidenced that FVIII·vWF complex inhibited RANKL-induced osteoclastogenesis and enhanced the inhibitory effect of OPG. Interestingly, we revealed by surface plasmon resonance that FVIII·vWF complex bound to RANKL, whereas recombinant FVIII and vWF did not. By modeling, we showed that the OPG binding domain to the A1 domain of vWF was closely located and partially overlapped to its binding site to RANKL. Then, we demonstrated that FVIII·vWF complex cancelled the inhibitory activity of OPG on TRAIL-induced apoptosis and characterized interactions between these molecules. The present work evidenced a direct activity of FVIII·vWF complex on osteoclasts and on induced cell apoptosis, pointing out its potential involvement in physiological bone remodeling or in bone damages associated with severe hemophilia and cancer development
Biochemical, Structural and Molecular Dynamics Analyses of the Potential Virulence Factor RipA from Yersinia pestis
Human diseases are attributed in part to the ability of pathogens to evade the eukaryotic immune systems. A subset of these pathogens has developed mechanisms to survive in human macrophages. Yersinia pestis, the causative agent of the bubonic plague, is a predominately extracellular pathogen with the ability to survive and replicate intracellularly. A previous study has shown that a novel rip (required for intracellular proliferation) operon (ripA, ripB and ripC) is essential for replication and survival of Y. pestis in postactivated macrophages, by playing a role in lowering macrophage-produced nitric oxide (NO) levels. A bioinformatics analysis indicates that the rip operon is conserved among a distally related subset of macrophage-residing pathogens, including Burkholderia and Salmonella species, and suggests that this previously uncharacterized pathway is also required for intracellular survival of these pathogens. The focus of this study is ripA, which encodes for a protein highly homologous to 4-hydroxybutyrate-CoA transferase; however, biochemical analysis suggests that RipA functions as a butyryl-CoA transferase. The 1.9 Ă
X-ray crystal structure reveals that RipA belongs to the class of Family I CoA transferases and exhibits a unique tetrameric state. Molecular dynamics simulations are consistent with RipA tetramer formation and suggest a possible gating mechanism for CoA binding mediated by Val227. Together, our structural characterization and molecular dynamic simulations offer insights into acyl-CoA specificity within the active site binding pocket, and support biochemical results that RipA is a butyryl-CoA transferase. We hypothesize that the end product of the rip operon is butyrate, a known anti-inflammatory, which has been shown to lower NO levels in macrophages. Thus, the results of this molecular study of Y. pestis RipA provide a structural platform for rational inhibitor design, which may lead to a greater understanding of the role of RipA in this unique virulence pathway
Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.
RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 â„60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Mise en Ă©vidence de cellules-souches neurales dans le complexe vagal dorsal de rongeur adulte et recherche de leurs facteurs de contrĂŽle
Le complexe vagal dorsal (CVD) est un centre neurovégétatif cérébral présentant plasticité et neurogenÚse chez le rat adulte. In vivo, j'ai démontré l'existence de cellules prolifératives dans le CVD par immunohistochimie de Ki-67 et par western-blot des cyclines D. In vitro, sur cultures primaires de CVD microdisséqué, j'ai obtenu des neurosphÚres auto-renouvelables contenant neurones et cellules gliales. Donc le CVD de rat adulte contient des cellules-souches neurales. J'ai recherché des facteurs de contrÎle des cellules-souches du CVD par deux approches. In vivo, la stimulation proliférative post-lésionnelle du CVD a été correlée, par RT-PCR et par biopuce à ADN, avec l'induction de deux mitogÚnes : les facteurs de croissance EGF et BDNF. In vitro, la prolifération des cellules souches neurales a été inhibée par l'hormone anorexigÚne leptine. Ces résultats de neurobiologie cellulaire apportent une vision nouvelle des processus intégratifs en physiologie neurovégétative.AIX-MARSEILLE3-BU Sc.St JérÎ (130552102) / SudocSudocFranceF
Orthodontie accélérée par corticotomies alvéolaires : approche clinique et expérimentale
Les corticotomies de lâos alvĂ©olaire permettent dâaccĂ©lĂ©rer les mouvements dentaires par
rapport Ă un traitement orthodontique conventionnel. Actuellement, les demandes de traitement
chez lâadulte ne cessent dâaugmenter, et cette population souhaite que le traitement soit
le plus rapide possible.
Nous prĂ©sentons deux cas cliniques dâadultes. Des corticotomies alvĂ©olaires ont Ă©tĂ© rĂ©alisĂ©es,
associées à un traitement orthodontique conventionnel combiné à une chirurgie orthognatique.
De façon concomitante, nous avons réalisé une étude expérimentale sur de gros animaux.
Ces approches complémentaires, cliniques et expérimentales, ont toutes les deux montré une
diminution du temps nécessaire au déplacement orthodontique.
Les résultats cliniques corroborent les données expérimentales et confirment que cette
technique permet le traitement de malocclusions plus rapidement quâun traitement orthodontique
conventionnel. Notre Ă©tude nâa montrĂ© aucun effet secondaire, tant sur la vitalitĂ© pulpaire
que sur la forme radiculaire
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