Effect of sonic hedgehog/β-TCP composites on bone healing within the critical-sized rat femoral defect

The creation of entirely synthetically derived bone substitute materials which are as effective as autologous bone grafts is desirable. Osteogenesis involves the concerted action of several proteins within a signaling cascade. Hedgehog proteins act upstream of this cascade, inducing the expression of various bone morphogenetic proteins (BMPs) and promoting physiological bone healing. Therefore, the hypothesis that hedgehog signaling in bone defects improves bone healing more than BMP signaling alone was tested. Recombinant N-terminal sonic hedgehog protein (N-SHh), BMP-2 or a combination of the two was added to β-tricalcium phosphate (β-TCP) and 5-mm femoral midshaft defects in nude rats were filled with these composites. The defects were stabilized with mini-plates. After eight weeks, the animals were sacrificed and the femora were explanted. The radiological evaluation was followed by a three-point bending test and histological examination. BMP-2/β-TCP composites showed a trend of increased stiffness compared with the controls (β-TCP without protein). N-SHh/β-TCP composites had lower stiffness compared with the control group and the N-SHh/BMP-2/β-TCP composites also had lower average stiffness compared with the controls (all not significant). Histomorphometry, however, revealed abundant cartilage and bone core formation in the N-SHh-composite groups. The sum of the new cartilage and bone was highest in the combination group N-SHh/BMP-2 (not significant). The addition of N-SHh to bone substitute materials appears to delay bone healing at the applied concentration and observation time but also showed a trend for higher amounts of ossifying cartilage

Human endothelial-like differentiated precursor cells maintain their endothelial characteristics when cocultured with mesenchymal stem cell and seeded onto human cancellous bone

Introduction. Cancellous bone is frequently used for filling bone defects in a clinical setting. It provides favourable conditions for regenerative cells such as MSC and early EPC. The combination of MSC and EPC results in superior bone healing in experimental bone healing models. Materials and Methods. We investigated the influence of osteogenic culture conditions on the endothelial properties of early EPC and the osteogenic properties of MSC when cocultured on cancellous bone. Additionally, cell adhesion, metabolic activity, and differentiation were assessed 2, 6, and 10 days after seeding. Results. The number of adhering EPC and MSC decreased over time; however the cells remained metabolically active over the 10-day measurement period. In spite of a decline of lineage specific markers, cells maintained their differentiation to a reduced level. Osteogenic stimulation of EPC caused a decline but not abolishment of endothelial characteristics and did not induce osteogenic gene expression. Osteogenic stimulation of MSC significantly increased their metabolic activity whereas collagen-1α and alkaline phosphatase gene expressions declined. When cocultured with EPC, MSC’s collagen-1α gene expression increased significantly. Conclusion. EPC and MSC can be cocultured in vitro on cancellous bone under osteogenic conditions, and coculturing EPC with MSC stabilizes the latter’s collagen-1α gene expression

High calcium bioglass enhances differentiation and survival of endothelial progenitor cells, inducing early vascularization in critical size bone defects

Early vascularization is a prerequisite for successful bone healing and endothelial progenitor cells (EPC), seeded on appropriate biomaterials, can improve vascularization. The type of biomaterial influences EPC function with bioglass evoking a vascularizing response. In this study the influence of a composite biomaterial based on polylactic acid (PLA) and either 20 or 40% bioglass, BG20 and BG40, respectively, on the differentiation and survival of EPCs in vitro was investigated. Subsequently, the effect of the composite material on early vascularization in a rat calvarial critical size defect model with or without EPCs was evaluated. Human EPCs were cultured with β-TCP, PLA, BG20 or BG40, and seeding efficacy, cell viability, cell morphology and apoptosis were analysed in vitro. BG40 released the most calcium, and improved endothelial differentiation and vitality best. This effect was mimicked by adding an equivalent amount of calcium to the medium and was diminished in the presence of the calcium chelator, EGTA. To analyze the effect of BG40 and EPCs in vivo, a 6-mm diameter critical size calvarial defect was created in rats (n = 12). Controls (n = 6) received BG40 and the treatment group (n = 6) received BG40 seeded with 5×105 rat EPCs. Vascularization after 1 week was significantly improved when EPCs were seeded onto BG40, compared to implanting BG40 alone. This indicates that Ca2+ release improves EPC differentiation and is useful for enhanced early vascularization in critical size bone defects

Beschleunigte Knochenheilung durch frühe Vaskularisierung mittels Implantation von EPC und MSC auf beta-TCP im Knochendefektmodell der Ratte

Fragestellung: In einem ausgedehnten Knochendefekt kann das Einwachsen von knochenbildenden Zellen limitiert sein, da ohne Gefässe die Ernährung der regenerativen Zellen im Knochenkonstrukt insuffizient ist. Endotheliale Progenitorzellen (EPC) sind wichtig bei der Neovaskularisierung. Die frühe Vaskularisierung von grossen Knochendefekten kann für das Überleben und die Funktion von mesenchymalen Stammzellen (MSC) und knochenbildenden Zellen entscheidend sein. Kann die Implantation von EPC und MSC auf osteokonduktiven beta-Tricalciumphosphat (beta-TCP) in einem "critical-size" Knochendefekt des Femur von athymischen Ratten die frühe Vaskularisierung und die Knochenheilung in vivo verbessern? Methodik: Humane EPC wurden aus Buffy-Coat und humane MSC aus Knochenmarkaspirat durch Dichtezentrifugation isoliert. 2.5 x 105 kultivierte und differenzierte EPC und MSC wurden in vitro auf beta-TCP geladen. In 145 athymischen, männlichen Ratten wurde das Femur osteotomiert, ein 5 mm Knochendefekt erzeugt und mit Fixateur externe stabilisiert. Die Knochendefekte wurden mit beta-TCP (Gruppe 1), beta-TCP und MSC (Gruppe 2), beta-TCP und EPC (Gruppe 3), beta-TCP und EPC und MSC (Gruppe 4) oder autologem Knochen (Gruppe 5) gefüllt. Nach 1 Woche (n=40), 4 Wochen (n=40), 8 Wochen (n=40) und 12 Wochen (n=25) wurden die Ratten getötet. Bei Pinlockerung wurde die Ratte ausgeschlossen. Die (immun)histologische Analyse (Färbung mit HE, VEGF-R2, vWF) der Vaskularisierung und Knochenneubildung erfolgte mit Image-Analysis-System. Nach 8 und 12 Wochen erfolgte ein µCT und ein 4-Punkte-Biegungstest. Für die statistische Analyse wurde der Kruskal-Wallis-Test verwendet. Ergebnisse und Schlussfolgerungen: Nach 1 Woche zeigte sich bei der Implantation von EPC/MSC und EPC allein signifikant mehr primitive vaskuläre Plexus (p=0.01;p=0.048) als in Vergleichsgruppen. Im Vergleich zur TCP Gruppe war in allen anderen Versuchsgruppen signifikant mehr Knochenneubildung zu sehen (p<0.01). Ausserdem war in der EPC/MSC-Gruppe signifikant mehr Knochenbildung zu erkennen als in der MSC-Gruppe (p=0.03). Nach 12 Wochen zeigten alle Gruppen eine knöcherne Durchbauung des Defektes, jedoch zeigten bereits 8 Wochen nach Implantation von MSC/EPC 83% der Defekte eine stabile, knöcherne Durchbauung. Bei der Implantation von MSC kam es in 18% der Knochendefekte zum knöchernen Durchbau. Alle anderen experimentellen Gruppen zeigten nach 8 Wochen keine knöcherne Durchbauung. Diese Resultate konnten im µCT, biomechanischen Test und in der Histologie quantifiziert werden. EPC scheinen die frühe Vaskularisierung innerhalb eines Knochenkonstrukt in vivo zu stimulieren und das Einwachsverhalten von MSC zu verbessern, was zu einer beschleunigten Knochenheilung im Knochendefektmodell der Ratte führt

Primary Analysis of Phase 2 Results for Cemiplimab in Patients (pts) with Locally Advanced Basal Cell Carcinoma (laBCC) who Progress on or are Intolerant to Hedgehog Inhibitors (HHIs)

Abstract not available

Syndrome VEXAS : quand y penser ?

VEXAS syndrome was recently discovered in patients who developed late in adulthood an inflammatory syndrome with fever, cytopenias, dysplastic bone marrow, cutaneous and pulmonary neutrophilic inflammation, arthritis, chondritis, or vasculitis. It is the result of an inactivating somatic mutation affecting methionine codon 41 of the UBA1 gene which encodes an ubiquitin activating enzyme (E1). Systemic corticosteroids generally reduce symptoms, while other immunosuppressive drugs only have limited long-term effects. Azacitidine is a promising treatment, but further studies are warranted. Here, we describe 2 new cases including one associated with pyoderma gangrenosum and cryoglobulinemia.Le syndrome VEXAS (Vacuoles, E1 Enzyme, X-Linked, Auto- Inflammatory, Somatic Syndrome) a été récemment découvert chez des patients développant tardivement à l’âge adulte un syndrome inflammatoire associé à de la fièvre, des cytopénies, une moelle osseuse dysplasique, une inflammation neutrophilique cutanée et pulmonaire, des arthrites, des chondrites ou des vasculites. Il est le résultat d’une mutation somatique inactivatrice affectant le codon méthionine 41 du gène UBA1 qui encode une enzyme E1 activant l’ubiquitine. Les corticostéroïdes systémiques permettent généralement de diminuer les symptômes alors que les autres immunosuppresseurs ont un effet limité à long terme. L’azacitidine est l’un des traitements ayant démontré une efficacité, cependant de nouvelles études sont souhaitables. Nous décrivons ici 2 cas dont l’un est associé à un pyoderma gangrenosum et une cryoglobulinémie

Safety and feasibility of cell-based therapy of autologous bone marrow-derived mononuclear cells in plate-stabilized proximal humeral fractures in humans

Abstract Background Local implantation of ex vivo concentrated, washed and filtrated human bone marrow-derived mononuclear cells (BMC) seeded onto β-tricalciumphosphate (TCP) significantly enhanced bone healing in a preclinical segmental defect model. Based on these results, we evaluated in a first clinical phase-I trial safety and feasibility of augmentation with preoperatively isolated autologous BMC seeded onto β-TCP in combination with angle stable plate fixation for the therapy of proximal humeral fractures as a potential alternative to autologous bone graft from the iliac crest. Methods 10 patients were enrolled to assess whether cell therapy with 1.3 × 106 autologous BMC/ml/ml β-TCP, collected on the day preceding the definitive surgery, is safe and feasible when seeded onto β-TCP in patients with a proximal humeral fracture. 5 follow-up visits for clinical and radiological controls up to 12 weeks were performed. Results β-tricalciumphosphate fortification with BMC was feasible and safe; specifically, neither morbidity at the harvest site nor at the surgical wound site were observed. Neither local nor systemic inflammation was noted. All fractures healed within the observation time without secondary dislocation. Three adverse events were reported: one case each of abdominal wall shingles, tendon loosening and initial screw perforation, none of which presumed related to the IND. Conclusions Cell therapy with autologous BMC for bone regeneration appeared to be safe and feasible with no drug-related adverse reactions being described to date. The impression of efficacy was given, although the study was not powered nor controlled to detect such. A clinical trial phase-II will be forthcoming in order to formally test the clinical benefit of BMC-laden β-TCP for PHF patients. Trial registration The study was registered in the European Clinical Trial Register as EudraCT No. 2012-004037-17. Date of registration 30th of August 2012. Informed consent was signed from all patients enrolled

Case Report: Severe Complement-Mediated Thrombotic Microangiopathy in IgG4-Related Disease Secondary to Anti-Factor H IgG4 Autoantibodies

Objective: To first describe and estimate the potential pathogenic role of Ig4 autoantibodies in complement-mediated thrombotic microangiopathy (TMA) in a patient with IgG4-related disease (IgG4-RD). Methods: This study is a case report presenting a retrospective review of the patient's medical chart. Plasma complement C3 and C4 levels, immunoglobulin isotypes and subclasses were determined by nephelometry, the complement pathways' activity (CH50, AP50, MBL) using WIESLAB® Complement System assays. Human complement factor H levels, anti-complement factor H auto-antibodies were analyzed by ELISA, using HRP-labeled secondary antibodies specific for human IgG, IgG4, and IgA, respectively. Genetic analyses were performed by exome sequencing of 14 gens implicated in complement disorders, as well as multiplex ligation-dependent probe amplification looking specifically for CFH, CFHR1-2-3, and 5

EBI2 expression and function: robust in memory lymphocytes and increased by natalizumab in multiple sclerosis

The interaction between oxysterols and the G-protein coupled receptor Epstein-Barr virus induced gene 2 (EBI2) fine tunes immune cell migration, a mechanism efficiently targeted by several disease-modifying treatments developed to treat multiple sclerosis (MS). We previously showed that memory CD4+ T lymphocytes migrate specifically in response to 7α,25-dihydroxycholesterol (7α,25-OHC) via EBI2 in the MS murine model experimental autoimmune encephalomyelitis. However, EBI2 expression profile in human lymphocytes both in healthy and MS donors is unknown. Here, we characterize EBI2 biology in human lymphocytes. We observed that EBI2 is functionally expressed on memory CD4+ T cells and is enhanced under natalizumab treatment, a drug fighting MS by targeting immune cell trafficking. These data suggest a significant role for EBI2 in human CD4+ T cell migration, notably in patients with MS. A better knowledge of EBI2 involvement in autoimmunity may therefore lead to an improved understanding of the physiopathology of MS