The Innate Immune Response in Eisenia Fetida to Microbial Challenges

The common earthworm, Eisenia fetida, exhibits a rudimentary immune system. The earthworm needs cellular and chemical responses against a constant microbial exposure from its natural environment. Some cellular and chemical responses are found in the coelomic fluid and have been shown to demonstrate anti-microbial characteristics. This project uses microscopy and modified staining techniques to differentiate and categorize the cellular components found in the coelomic fluid. Following a microbial challenge by Klebsiella pneumoniae, an inflammatory response was initiated. Six groups of earthworms were injected with 0.05 ml of 1.0 x 106 cfu /ml K. pneumoniae on day one and tested over a period of five days. A group of three worms was shocked each day for the next five days to cause the coelomic fluid and cells to pass through the body wall. The coelomic fluid was placed directly on glass slides, dried and stained with a modified Wright’s stain using a wash buffer solution with a pH of 6.3. The stained cells were differentiated into four categories. Total cell counts were determined. The data indicated a marked proliferation in total cell counts in comparison to the control worms. This trend of increasing total cell counts continued over the five days. The percent ages of the four types of coelomic cells from the differential remained constant. Cells were photographed and documented for comparisons. Additional studies are ongoing to determine how long the Eisenia fetida take to remove Klebsiella pneumoniae from the coelomic cavity

Elastin-Derived Peptides Are New Regulators of Thrombosis

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Ticagrelor Prevents Endothelial Cell Apoptosis through the Adenosine Signalling Pathway in the Early Stages of Hypoxia

International audienceBackground: Several studies have reported the beneficial effects of anti-platelet drugs in cardioprotection against ischaemia-reperfusion injuries. To date, no studies have focused on the indirect cytoprotective effects of ticagrelor via adenosine receptor on the endothelium. Method: By evaluating cell viability and cleaved caspase 3 expression, we validated a model of endothelial cell apoptosis induced by hypoxia. In hypoxic endothelial cells treated with ticagrelor, we quantified the extracellular concentration of adenosine, and then we studied the involvement of adenosine pathways in the cytoprotective effect of ticagrelor. Results: Our results showed that 10 µM ticagrelor induced an anti-apoptotic effect in our model associated with an increase of extracellular adenosine concentration. Similar experiments were conducted with cangrelor but did not demonstrate an anti-apoptotic effect. We also found that A2B and A3 adenosine receptors were involved in the anti-apoptotic effect of ticagrelor in endothelial cells exposed to 2 h of hypoxia stress. Conclusion: we described an endothelial cytoprotective mechanism of ticagrelor against hypoxia stress, independent of blood elements. We highlighted a mechanism triggered mainly by the increased extracellular bioavailability of adenosine, which activates A2B and A3 receptors on the endothelium

Critical limb ischemia: thrombogenic evaluation of two autologous cell therapy products and biologic profile in treated patients

International audienceBackground: Cell therapy has been proposed as a salvage limb procedure in critical limb ischemia (CLI). Autologous cell therapy products (CTP) are obtained from patients with advanced peripheral arterial disease to be injected at the site of ischemia. Thrombogenicity of CTPs has not yet been assessed. The objectives were: 1) to assess thrombotic risk in candidates for cell therapy, 2) to evaluate two different CTPs in terms of thrombogenic potential, and 3) to evaluate clinical thrombotic events.Study design and methods: In this ancillary study of a Phase I and II clinical trial, bone marrow (BM)-CTPs (n = 20) and CTPs obtained by cytapheresis (peripheral blood [PB]-CTPs; n = 20) were compared. Inflammatory and coagulation markers were measured at baseline and 24 hours after CTP implantation. CTP cell content and tissue factor (TF) expression (mRNA and protein) were analyzed. Thrombin generation assessed CTP-related thrombogenicity.Results: All patients presented cardiovascular risk factors. At baseline, the patients' biologic profile was characterized by high levels of fibrinogen, C-reactive protein (CRP), D-dimer, interleukin (IL)-6, and plasmatic TF, whereas IL-10 was low. Although different in terms of cell composition, both BM- and PB-CTPs support low thrombin generation. Twenty-four hours after implantation, biologic markers remained stable in the PB-CTP group, except for IL-6. In the BM-CTP group, a significant increase of IL-6 but also of CRP and D-dimer was observed. Clinically, one single patient developed deep vein thrombosis 24 hours after the implantation of autologous PB-CTP.Conclusion: CTPs supported low thrombin generation and were well tolerated after calf implantation

In vivo efficacy of endothelial growth medium stimulated mesenchymal stem cells derived from patients with critical limb ischemia

International audienceBackground: Cell therapy has been proposed for patients with critical limb ischemia (CLI). Autologous bone marrow derived cells (BMCs) have been mostly used, mesenchymal stem cells (MSCs) being an alternative. The aim of this study was to characterize two types of MSCs and evaluate their efficacy.Methods: MSCs were obtained from CLI-patients BMCs. Stimulated-(S-) MSCs were cultured in endothelial growth medium. Cells were characterized by the expression of cell surface markers, the relative expression of 6 genes, the secretion of 10 cytokines and the ability to form vessel-like structures. The cell proangiogenic properties was analysed in vivo, in a hindlimb ischemia model. Perfusion of lower limbs and functional tests were assessed for 28 days after cell infusion. Muscle histological analysis (neoangiogenesis, arteriogenesis and muscle repair) was performed.Results: S-MSCs can be obtained from CLI-patients BMCs. They do not express endothelial specific markers but can be distinguished from MSCs by their secretome. S-MSCs have the ability to form tube-like structures and, in vivo, to induce blood flow recovery. No amputation was observed in S-MSCs treated mice. Functional tests showed improvement in treated groups with a superiority of MSCs and S-MSCs. In muscles, CD31+ and αSMA+ labelling were the highest in S-MSCs treated mice. S-MSCs induced the highest muscle repair.Conclusions: S-MSCs exert angiogenic potential probably mediated by a paracrine mechanism. Their administration is associated with flow recovery, limb salvage and muscle repair. The secretome from S-MSCs or secretome-derived products may have a strong potential in vessel regeneration and muscle repair. Trial registration NCT0053310

The importance of the effect of shear stress on endothelial cells in determining the performance of hemoglobin based oxygen carriers

The lack of blood donations and the threat of infections from blood and blood products have led to extensive research into the development of blood substitutes. The latest generation of hemoglobin based oxygen carriers (HBOC) has been shown to induce side effects like hypertension, vasoconstriction, inflammation and oxidative stress. HBOC are able to restore volemia and transport oxygen after a hemorrhagic shock, the reperfusion leading to the restoration of the blood flow in vessels. We propose an innovative approach, more closely emulating clinical situations, to assess the impact of HBOC perfusion on endothelial cells (EC) in vitro. Through this approach we quantified levels of oxidative stress, vasoactive factors and inflammation. EC were cultivated under a laminar flow to reproduce the return of shear stress (SS) during the reperfusion. We showed that heme oxygenase I transcription correlated with changes in oxidatively modified heme and methemoglobin; all were lower under SS. SS induced increased nitric oxide production, which may have implications for the mechanism of in vivo vasoconstriction and hypertension. E-selectin changes under SS were greater than those of ICAM-1. Our results demonstrate how it is essential to include SS in assays attempting to understand the potential vascular side effects of HBOC perfusion. © 2008 Elsevier Ltd. All rights reserved