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Le Touquet – Paris-Plage, France

Zwingenberger S.,Stanford University | Zwingenberger S.,TU Dresden | Yao Z.,Stanford University | Jacobi A.,TU Dresden | And 15 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2013

Mesenchymal stromal cell (MSCs) are key cellular components for site-specific tissue regeneration. The chemokine stromal derived factor 1 alpha (SDF-1α) is known to attract stem cells via the C-X-C chemokine receptor-4 (CXCR4) receptor. The aim of the study was to develop a model for stem cell attraction using SDF-1α overexpressing fat tissue grafts. Murine MSCs were lentiviral transduced to express the genes for enhanced green fluorescent protein, firefly luciferace, and human CXCR4 (hCXCR4). Murine fat tissue was adenoviral transduced to express SDF-1α and red fluorescent protein transgenes. MSCs were cultured on transwells with SDF-1α containing supernatants from transduced fat tissue. The numbers of migrated MSCs in four groups (with hCXCR4 positive (+) or hCXCR4 negative (-) MSCs with or without SDF-1α containing supernatant) were investigated. After 36 h of culture, 9025 ± 925 cells migrated through the membrane of the transwells in group 1 (CXCR4+/SDF-1α+), 4817 ± 940 cells in group 2 (CXCR4-/SDF-1α+), 2050 ± 766 cells in group 3 (CXCR4+/SDF-1α- ), and 2108 ± 426 cells in group 4 (CXCR4-/SDF-1α-). Both, the presence of SDF-1α and the expression of hCXCR4 significantly increased the migration rates (p < 0.0001). MSCs overexpressing the CXCR4 receptor by lentiviral transduction are highly attracted by medium from SDF-1α expressing fat tissue in vitro. Thus, SDF-1α activated tissue grafts may be a strategy to enhance site-specific musculoskeletal tissue regeneration. Copyright © 2012 Wiley Periodicals, Inc. Source

Zwingenberger S.,Stanford University | Zwingenberger S.,TU Dresden | Yao Z.,Stanford University | Jacobi A.,TU Dresden | And 14 more authors.
Tissue Engineering - Part A | Year: 2014

Treatment of critical size bone defects is challenging. Recent studies showed that the cytokine stromal cell-derived factor 1 alpha (SDF-1α) has potential to improve the bone regenerative effect of low bone morphogenetic protein 2 (BMP-2) concentrations. The goal of this study was to demonstrate the combined effect of SDF-1α and BMP-2 on bone regeneration and stem cell recruitment using a critical size femoral bone defect model. A total of 72 mice were randomized to six groups. External fixators were implanted onto the right femur of each mouse and 3 mm defects were created. Depending on the group affiliation, adenovirally activated fat tissue grafts expressing SDF-1α or/and BMP-2 were implanted at the defect site. One day after operation, 1×106 murine mesenchymal stromal cells (MSCs), lentivirally transduced to express the gene enhanced green fluorescent protein (eGFP), firefly luciferase, and CXCR4 were injected systemically in selected groups. Migration of the injected MSCs was observed by bioluminescence imaging on days 0, 2, 4, 6, 8, 10, 12, 14, 21, 28, and 42. After 6 weeks, animals were euthanized and 80 μm CT-scans were performed. For histological investigations, hematoxylin and eosin-, tartrate-resistant acid phosphatase-, alkaline phosphatase-, and anti-eGFP-stained sections were prepared. BMP-2 and SDF-1α combined at the defect site increased bone volume (BV) (2.72 mm3; 95% CI 1.95-3.49 mm3) compared with the negative control group (1.80 mm3; 95% CI 1.56-2.04 mm3; p<0.05). In addition, histological analysis confirmed a higher degree of bone healing in the BMP-2 and SDF-1α combined group compared with the negative control group. Bioluminescence imaging demonstrated higher numbers of migrated MSCs toward the defect site in the presence of both BMP-2 and SDF-1α at the defect site. Furthermore, eGFP-labeled migrated MSCs were found in all defect areas, when cells were injected. The ratio of osteoblasts to osteoclasts, assessed by immunohistological staining, was higher and thus showed a trend toward more bone formation for the combined use of BMP-2 and SDF-1α compared with all other groups. This study demonstrated that SDF-1α enhanced BMP-2 mediated bone healing in a critical size segmental bone defect model. Notably, both proteins alone also provided a cumulative effect on MSC attraction toward the site of injury. © 2014 Mary Ann Liebert, Inc. Source

Boulu P.,Pain Unit | Hayem G.,Bichat Teaching Hospital
European Spine Journal | Year: 2012

Introduction Epidural steroid injections (ESIs) have been widely used for over 50 years in the treatment of low-back pain with radiculopathy. Most interventional pain physicians strongly believe in their efficacy and safety. Recent Cochrane systematic reviews have disclosed controversial results and have questioned the effectiveness of ESIs. Moreover, a few neurological adverse events have been reported recently. Methods A literature search of systematic reviews analysing the effectiveness and complications of ESIs was carried out. The scientific quality of the reviews was assessed using the validated index of Oxman and Guyatt.Werelied on data abstraction and quality ratings of the placebo-controlled trials as reported by high-quality systematic reviews. Results Two types of systematic reviews were found. The Cochrane high-quality systematic reviews combining the three approaches and different pathologies were predominantly non-conclusive. The second type of review, emanating from the US Evidence-based Practice Centers, distinguishing between the routes of administration and between the principal pathologies found a moderate shortterm benefit of ESIs versus placebo in patients with disc herniation and radiculitis, in keeping with the clinical experience. ESIs are generally well tolerated and most complications are related to technical problems. Cases of paraplegia, complicating the foraminal route and related to the violation of a radiculomedullary artery, have been recently reported. They are predominantly observed in previously operated patients. Conclusions Epidural steroid injections have a moderate short-term effect in the management of low-back pain with radiculopathy. Severe neurological complications are exceptional, but call for research for alternative approaches to the foramen as well as for means to detect an eventual arterial injury. © 2011 Springer-Verlag. Source

Goodman S.B.,Stanford University | Gibon E.,University Paris Diderot | Gibon E.,University of Paris Descartes | Pajarinen J.,Stanford University | And 8 more authors.
Journal of the Royal Society Interface | Year: 2014

Wear particles and by-products from joint replacements and other orthopaedic implants may result in a local chronic inflammatory and foreign body reaction. This may lead to persistent synovitis resulting in joint pain and swelling, periprosthetic osteolysis, implant loosening and pathologic fracture. Strategies to modulate the adverse effects of wear debris may improve the function and longevity of joint replacements and other orthopaedic implants, potentially delaying or avoiding complex revision surgical procedures. Three novel biological strategies to mitigate the chronic inflammatory reaction to orthopaedic wear particles are reported. These include (i) interference with systemic macrophage trafficking to the local implant site, (ii) modulation of macrophages from an M1 (pro-inflammatory) to an M2 (anti-inflammatory, pro-tissue healing) phenotype in the periprosthetic tissues, and (iii) local inhibition of the transcription factor nuclear factor kappa B (NF-κB) by delivery of an NF-κB decoy oligodeoxynucleotide, thereby interfering with the production of pro-inflammatory mediators. These three approaches have been shown to be viable strategies for mitigating the undesirable effects of wear particles in preclinical studies. Targeted local delivery of specific biologics may potentially extend the lifetime of orthopaedic implants. © 2014 The Author(s) Published by the Royal Society. All rights reserved. Source

Grosjean C.,Bichat Teaching Hospital | Hurtado-Nedelec M.,Bichat Teaching Hospital | Nicaise-Roland P.,Bichat Teaching Hospital | Ferreyra-Dillon R.,Bichat Teaching Hospital | And 10 more authors.
Journal of Rheumatology | Year: 2010

Objective. To determine the prevalence of the most often tested autoantibodies in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. Methods. We identified 90 patients seen in our unit between June 2002 and June 2009, and diagnosed according to the proposed criteria for SAPHO syndrome. Demographic and clinical data were collected as well as immunological results, including antinuclear, antithyroid peroxydase (TPO), antithyroid globulin (Tg), antigastric parietal cell, antismooth muscle, antimitochondria, and anti-liver-kidney microsome (LKM) antibodies. Anticyclic citrullinated peptide (CCP) antibodies were analyzed in 69 patients, antibodies to soluble extractable nuclear antigens in 43, anti-double-stranded DNA (dsDNA) antibodies in 22 [depending on the type of fluorescence of antinuclear antibody (ANA)], and antiendomysium antibodies in 55. Results. Autoantibodies were found in 20 patients (22.2%): 14 patients (15.5%) had positive ANA (titer ≥ 1/160); among them, 10 (11%) patients never took a lupus-inducing drug. Antithyroid antibodies (anti-TPO and/or anti-Tg antibodies) were found in only 3 patients (3.3%). Three patients (3.3%) were positive for antigastric parietal cell antibodies and 4 (4.4%) were weakly positive for antismooth muscle antibodies. Antimitochondria and LKM antibodies were negative in all 90 patients.Anti-CCP and anti-dsDNA antibodies were negative in the 69 and 22 patients tested, respectively. One out of 43 patients (2.3%) had anti-SSA antibodies. Antiendomysium antibodies were negative in the 55 patients tested. Conclusion. Our study indicates an increased prevalence of autoantibodies in SAPHO syndrome, with no specific profile. We failed to confirm the reports of an increased prevalence of antithyroid antibodies. These results tend to support a link between autoimmunity and SAPHO syndrome. The Journal of Rheumatology Copyright © 2010. All rights reserved. Source

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