Alterations in plasma soluble vascular endothelial growth factor receptor-1 (sFlt-1) concentrations during coronary artery bypass graft surgery: relationships with post-operative complications

<p>Abstract</p> <p>Background</p> <p>Plasma concentrations of sFlt-1, the soluble form of the vascular endothelial growth factor receptor (VEGF), markedly increase during coronary artery bypass graft (CABG) surgery with extracorporeal circulation (ECC). We investigated if plasma sFlt-1 values might be related to the occurrence of surgical complications after CABG.</p> <p>Methods</p> <p>Plasma samples were collected from the radial artery catheter before vascular cannulation and after opening the chest, at the end of ECC just before clamp release, after cross release, after weaning from ECC, at the 6^thand 24^thpost-operative hour. Thirty one patients were investigated. The presence of cardiovascular, haematological and respiratory dysfunctions was prospectively assessed. Plasma sFlt-1 levels were measured with commercially ELISA kits.</p> <p>Results</p> <p>Among the 31 investigated patients, 15 had uneventful surgery. Patients with and without complications had similar pre-operative plasma sFlt-1 levels. Lowered plasma sFlt-1 levels were observed at the end of ECC in patients with haematological (p = 0.001, ANOVA) or cardiovascular (p = 0.006) impairments, but not with respiratory ones (p = 0.053), as compared to patients with uneventful surgery.</p> <p>Conclusion</p> <p>These results identify an association between specific post-CABG complication and the lower release of sFlt-1 during ECC. sFlt-1-induced VEGF neutralisation might, thus, be beneficial to reduce the development of post-operative adverse effects after CABG.</p

Effects of Ursolic Acid and its Analogues on Soybean 15-Lipoxygenase Activity and the Proliferation Rate of A human Gastric Tumour Cell Line

The authors have previously isolated and purified ursolic acid from heather flowers (Calluna vulgarts). This terpene was found to inhibit HL-60 leukaemic cell proliferation and arachidonic acid oxidative metabolism in various cell species. The effects of ursolic acid and its analogues on soybean 15-lipoxygenase activity and on the proliferation of a human gastric tumour cell line (HGT), have been assessed. These triterpenes inhibited soybean 15-lipoxygenase at its optimal activity (pH 9). The proliferation ofHGT was decreased in a dose-dependent manner. At 20 μM the rank order is: ursolic acid > uvaol > oleanolic acid > methyl ursolate. The carboxylic group at the C28 position of ursolic acid appears to be implicated in the inhibition of both lipoxygenase activity and cell proliferation. Thus methylation of this group decreases these two inhibitory properties. Oleanolic acid, which differs by the position of one methyl group (C20 instead of C19) is less inhibitory than ursolic acid. The lipophilicity of the terpene is also implicated since uvaol appears to be more inhibitory than methyl ursolate

In vitro and in vivo evaluation of superparamagnetic iron oxide nanoparticles coated by bisphosphonates: the effects of electrical charge and molecule length.

Physicochemical coating properties are often considered to be determining factors for in vivo characteristics of superparamagnetic iron oxide nanoparticles, used as contrast agent in Magnetic Resonance Imaging (MRI). To investigate the electrical charge (modified by zero, one or two ammonium groups) and the molecule length (3, 5 or 7 methylene chains) effects of bisphosphonate-type coatings, we assessed the complement activation, in vivo plasma and tissue relaxation time alterations of intravenously injected small iron oxide nanoparticles (&lt;25 nm) on male healthy Wistar rats. The presence of ammonium groups induces a weak activation of the complement whatever the size and the concentration of particles, whereas hydroxyethylenebisphosphonate (HEBP)-coated particles are poor complement activators only at the lowest concentration. In vivo, HEBP-coated nanoparticles have the greatest prolonged relaxation time effects, despite their higher negative electrical charge, contrary to two ammonium bearing coatings. No significant differences were observed between mono-ammonium molecular coatings

Interactions with M cells and macrophages as key steps in the pathogenesis of enterohemorrhagic Escherichia coli infections

Enterohemorrhagic Escherichia coli (EHEC) are food-borne pathogens that can cause serious infections ranging from diarrhea to hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS). Translocation of Shiga-toxins (Stx) from the gut lumen to underlying tissues is a decisive step in the development of the infection, but the mechanisms involved remain unclear. Many bacterial pathogens target the follicle-associated epithelium, which overlies Peyer's patches (PPs), cross the intestinal barrier through M cells and are captured by mucosal macrophages. Here, translocation across M cells, as well as survival and proliferation of EHEC strains within THP-1 macrophages were investigated using EHEC O157:H7 reference strains, isogenic mutants, and 15 EHEC strains isolated from HC/HUS patients. We showed for the first time that E. coli O157:H7 strains are able to interact in vivo with murine PPs, to translocate ex vivo through murine ileal mucosa with PPs and across an in vitro human M cell model. EHEC strains are also able to survive and to produce Stx in macrophages, which induce cell apoptosis and Stx release. In conclusion, our results suggest that the uptake of EHEC by M cells and underlying macrophages in the PP may be a critical step in Stx translocation and release in vivo. A new model for EHEC infection in humans is proposed that could help in a fuller understanding of EHEC-associated diseases

Release of soluble vascular endothelial growth factor receptor-1 (sFlt-1) during coronary artery bypass surgery

<p>Abstract</p> <p>Background</p> <p>This study was conducted to follow plasma concentrations of sFlt-1 and sKDR, two soluble forms of the vascular endothelial growth factor (VEGF) receptor in patients undergoing coronary artery bypass graft (CABG) surgery with extracorporeal circulation (ECC).</p> <p>Methods</p> <p>Plasma samples were obtained before, during and after surgery in 15 patients scheduled to undergo CABG. Levels of sFlt-1 and KDR levels were investigated using specific ELISA.</p> <p>Results</p> <p>A 75-fold increase of sFlt-1 was found during cardiac surgery, sFlt-1 levels returning to pre-operative values at the 6^thpost-operative hour. In contrast sKDR levels did not change during surgery. The ECC-derived sFlt-1 was functional as judge by its inhibitory effect on the VEGF mitogenic response in human umbilical vein endothelial cells (HUVECs). Kinetic experiments revealed sFlt-1 release immediately after the beginning of ECC suggesting a proteolysis of its membrane form (mFlt-1) rather than an elevated transcription/translation process. Flow cytometry analysis highlighted no effect of ECC on the shedding of mFlt-1 on platelets and leukocytes suggesting vascular endothelial cell as a putative cell source for the ECC-derived sFlt-1.</p> <p>Conclusion</p> <p>sFlt-1 is released during CABG with ECC. It might be suggested that sFlt-1 production, by neutralizing VEGF and/or by inactivating membrane-bound Flt-1 and KDR receptors, might play a role in the occurrence of post-CABG complication.</p

Inhibition of neurite outgrowth in differentiating mouse N2a neuroblastoma cells by phenyl saligenin phosphate: Effects on MAP kinase (ERK 1/2) activation, neurofilament heavy chain phosphorylation and neuropathy target esterase activity

Sub-lethal concentrations of the organophosphate phenyl saligenin phosphate (PSP) inhibited the outgrowth of axon-like processes in differentiating mouse N2a neuroblastoma cells (IC50 2.5 μM). A transient rise in the phosphorylation state of neurofilament heavy chain (NFH) was detected on Western blots of cell extracts treated with 2.5 μM PSP for 4 h compared to untreated controls, as determined by a relative increase in reactivity with monoclonal antibody Ta51 (anti-phosphorylated NFH) compared to N52 (anti-total NFH). However, cross-reactivity of PSP-treated cell extracts was lower than that of untreated controls after 24 h exposure, as indicated by decreased reactivity with both antibodies. Indirect immunofluorescence analysis with these antibodies revealed the appearance of neurofilament aggregates in the cell bodies of treated cells and reduced axonal staining compared to controls. By contrast, there was no significant change in reactivity with anti-a tubulin antibody B512 at either time point. The activation state of the MAP kinase ERK 1/2 increased significantly after PSP treatment compared to controls, particularly at 4 h, as indicated by increased reactivity with monoclonal antibody E-4 (anti-phosphorylated MAP kinase) but not with polyclonal antibody K-23 (anti-total MAP kinase). The observed early changes were concomitant with almost complete inhibition of the activity of neuropathy target esterase (NTE), one of the proposed early molecular targets in organophosphate-induced delayed neuropathy (OPIDN)

Interactions between Magnetic Nanowires and Living Cells : Uptake, Toxicity and Degradation

We report on the uptake, toxicity and degradation of magnetic nanowires by NIH/3T3 mouse fibroblasts. Magnetic nanowires of diameters 200 nm and lengths comprised between 1 {\mu}m and 40 {\mu}m are fabricated by controlled assembly of iron oxide ({\gamma}-Fe2O3) nanoparticles. Using optical and electron microscopy, we show that after 24 h incubation the wires are internalized by the cells and located either in membrane-bound compartments or dispersed in the cytosol. Using fluorescence microscopy, the membrane-bound compartments were identified as late endosomal/lysosomal endosomes labeled with lysosomal associated membrane protein (Lamp1). Toxicity assays evaluating the mitochondrial activity, cell proliferation and production of reactive oxygen species show that the wires do not display acute short-term (< 100 h) toxicity towards the cells. Interestingly, the cells are able to degrade the wires and to transform them into smaller aggregates, even in short time periods (days). This degradation is likely to occur as a consequence of the internal structure of the wires, which is that of a non-covalently bound aggregate. We anticipate that this degradation should prevent long-term asbestos-like toxicity effects related to high aspect ratio morphologies and that these wires represent a promising class of nanomaterials for cell manipulation and microrheology.Comment: 21 pages 12 figure