The proline-rich peptide Bac7(1-35) reduces mortality from Salmonella typhimurium in a mouse model of infection

<p>Abstract</p> <p>Background</p> <p>Bac7 is a proline-rich peptide with a potent <it>in vitro </it>antimicrobial activity against Gram-negative bacteria. Here we investigated its activity in biological fluids and <it>in vivo </it>using a mouse model of <it>S. typhimurium </it>infection.</p> <p>Results</p> <p>The efficacy of the active 1-35 fragment of Bac7 was assayed in serum and plasma, and its stability in biological fluids analyzed by Western blot and mass spectrometry. The ability of the peptide to protect mice against <it>Salmonella </it>was assayed in a typhoid fever model of infection by determination of survival rates and bacterial load in liver and spleen of infected animals. In addition, the peptide's biodistribution was evaluated by using time-domain optical imaging. Bac7(1-35) retained a substantial <it>in vivo </it>activity showing a very low toxicity. The peptide increased significantly the number of survivors and the mean survival times of treated mice reducing the bacterial load in their organs despite its rapid clearance.</p> <p>Conclusions</p> <p>Our results provide a first indication for a potential development of Bac7-based drugs in the treatment of salmonellosis and, eventually, other Gram-negative infections. The <it>in vivo </it>activity for this peptide might be substantially enhanced by decreasing its excretion rate or modifying the treatment schedule.</p

Meniscal ossicles as micro-CT imaging biomarker in a rodent model of antigen-induced arthritis: A synchrotron-based x-ray pilot study

It is increasingly recognized that early detection of bone erosion plays an important role in the overall evaluation of rheumatoid arthritis and in the choice of the correct treatment approach. Since an appropriate use of imaging biomarkers in preclinical settings offers the prospect of smaller and optimized sample size, in the present study we define an anatomical imaging biomarker that could be objectively measured from micro-CT imaging data as an indicator of bone erosion in arthritis process. The well-characterized antigen-induced arthritis (AIA) model in rats was used. The animals were divided into 2 groups: arthritic disease control and arthritic having been administrated with the tumor necrosis factor alpha-blocking agent (Humira). Rats were sacrificed in the acute phase of AIA; peripheral blood and synovial tissue were collected for assessment of arthritis. Ex vivo micro-CT tomography of knee joints was performed at the Elettra synchrotron light source (Trieste, Italy). Overall, results from this study suggest that use of high-resolution micro-CT analysis coupled with meniscal ossicles bone parameters quantification provide a powerful combination to enhance data interpretation and assessment of disease-modifying drugs in an animal model of arthritis

Conjugated PDT drug: photosensitizing activity and tissue distribution of PEGylated pheophorbide a.

The design of new photosensitizers with enhanced phototoxicity and pharmacokinetic properties remains a central challenge for cancer photodynamic therapy (PDT). In this study, Pheophorbide a (Pba) has been pegylated to methoxypolyethylene glycol (mPE G-Pba) to produce a soluble photosensitizer that exhibits a higher tissue distribution than free Pba. In vitro studies have shown that mPE G-Pba promotes a fairly strong photosensitizing effect in cancer cells, as previously observed for the unpegylated molecule. mPE G-Pba targets the mitochondria where, following photoactivation, ROS are produced which cause a cellular injury by lipid peroxidation. The effect of pegylation on the photosensitizer biodistribution has been examined in different selected organs of female mice, at different time points after intraperitoneal administration of the drug (50 μmol/Kg body weight). Other than free Pba, which showed a low tissue accumulation, mPE G-Pba has been detected in significant amounts (8 to 16 μg/ml) in liver, spleen, duodenum and kidney and, 3-5 hours after intraperitoneal injection, in moderate amounts (3 to 8 μg/ml) in brain and lung. In vivo optical imaging performed on living female C57/BL6 mice bearing a subcutaneous melanoma mass, showed that injected mPEG-Pba distributes all over the body, with an higher uptake in the tumor respect to free Pba. Our results indicate that although pegylation somewhat decreases the phototoxicity, it significantly increases the drug solubility and tissue distribution and tumor uptake of mPE G-Pba, making the conjugate an interesting photosensitizer for PDT

Targeted delivery of neutralizing anti-C5 antibody to renal endothelium prevents complement- dependent tissue damage

Complement activation is largely implicated in the pathogenesis of several clinical conditions and its therapeutic neutralization has proven effective in preventing tissue and organ damage. A problem that still needs to be solved in the therapeutic control of complement-mediated diseases is how to avoid side effects associated with chronic neutralization of the complement system, in particular, the increased risk of infections. We addressed this issue developing a strategy based on the preferential delivery of a C5 complement inhibitor to the organ involved in the pathologic process. To this end, we generated Ergidina, a neutralizing recombinant anti-C5 human antibody coupled with a cyclic-RGD peptide, with a distinctive homing property for ischemic endothelial cells and effective in controlling tissue damage in a rat model of renal ischemia/reperfusion injury (IRI). As a result of its preferential localization on renal endothelium, the molecule induced complete inhibition of complement activation at tissue level, and local protection from complement-mediated tissue damage without affecting circulating C5. The ex vivo binding of Ergidina to surgically removed kidney exposed to cold ischemia supports its therapeutic use to prevent posttransplant IRI leading to delay of graft function. Moreover, the finding that the ex vivo binding of Ergidina was not restricted to the kidney, but was also seen on ischemic heart, suggests that this RGD-targeted anti-C5 antibody may represent a useful tool to treat organs prior to transplantation. Based on this evidence, we propose preliminary data showing that Ergidina is a novel targeted drug to prevent complement activation on the endothelium of ischemic kidney

Intranasal administration of recombinant TRAIL down-regulates CXCL-1/KC in an ovalbumin-induced airway inflammation murine model.

Ovalbumin (OVA)-sensitized BALB/c mice were i.n. instilled with recombinant TNF-related apoptosis inducing ligand (TRAIL) 24 hours before OVA challenge. The total number of leukocytes and the levels of the chemokine CXCL-1/KC significantly increased in the bronchoalveolar lavage (BAL) fluids of allergic animals with respect to control littermates, but not in the BAL of mice i.n. pretreated with recombinant TRAIL before OVA challenge. In particular, TRAIL pretreatment significantly reduced the BAL percentage of both eosinophils and neutrophils. On the other hand, when TRAIL was administrated simultaneously to OVA challenge its effect on BAL infiltration was attenuated. Overall, the results show that the i.n. pretreatment with TRAIL down-modulated allergic airway inflammation

Multiple dye-doped NIR-emitting silica nanoparticles for both flow cytometry and in vivo imaging

Dye-doped near infrared-emitting silica nanoparticles (DD-NIRsiNPs) represent a valuable tool in bioimaging, because they provide sufficient brightness, resistance to photobleaching and consist of hydrophilic non-toxic materials. Here, we report the development of multiple dye-doped NIR emitting siNPs (mDD-NIRsiNPs), based on silica-PEG core-shell nanostructures doped with a donor-acceptor couple, exhibiting a tunable intensity profile across the NIR spectrum and suitable for both multiparametric flow cytometry analyses and time-domain optical imaging. In order to characterize the optical properties and fluorescence applications of the mDD-NIRsiNPs, we have characterized their performance by analyzing their in vivo biodistribution in healthy mice as well as in lymphoma bearing xenografts, and their suitability as contrast imaging agents for cell labeling and tracking. The mDD-NIRsiNPs features will be useful in designing new applications for imaging agents based on silica nanoparticles for different experimental disease models

In vivo distribution of beta 2 glycoprotein I under various pathophysiologic conditions

In vitro studies have documented beta 2 glycoprotein I (beta 2GPI) binding to endothelial cells (ECs) and trophoblast using antiphospholipid antibodies. The in vivo binding of beta 2GPI to these cells and the conditions that favor their interaction have not been investigated. We analyzed the in vivo distribution of cyanine 5.5-labeled beta 2GPI in mice and evaluated the effect of pregnancy and circulating antibodies on its tissue localization. The signal was detected in the liver by whole body scan and ex vivo analysis. The beta 2GPI failed to bind to the vascular endothelium and reacted only with the ECs of uterine vessels. In pregnant mice the protein was localized on ECs and trophoblast at the embryo implantation sites. Immunized mice showed a similar beta 2GPI biodistribution to naive mice but the immunized pregnant animals exhibited a significant increase in fetal loss associated with C3 and C9 deposition at the implantation sites. Treatment of mice with LPS after beta 2GPI-Cy5.5 injection promoted protein localization on gut and brain ECs associated with IgG, C1q, and C9 deposition in immunized mice. These findings indicate that beta 2GPI binding to EC requires priming with pro-inflammatory factors which is not needed for uterine and placental localization probably dependent on hormonal changes. (Blood. 2011;118(15):4231-4238

In Vivo Tracking of Murine Adipose Tissue-Derived Multipotent Adult Stem Cells and Ex Vivo Cross-Validation

Stem cells are characterized by the ability to renew themselves and to differentiate into specialized cell types, while stem cell therapy is believed to treat a number of different human diseases through either cell regeneration or paracrine effects. Herein, an in vivo and ex vivo near infrared time domain (NIR TD) optical imaging study was undertaken to evaluate the migratory ability of murine adipose tissue-derived multipotent adult stem cells [mAT-MASC] after intramuscular injection in mice. In vivo NIR TD optical imaging data analysis showed a migration of DiD-labelled mAT-MASC in the leg opposite the injection site, which was confirmed by a fibered confocal microendoscopy system. Ex vivo NIR TD optical imaging results showed a systemic distribution of labelled cells. Considering a potential microenvironmental contamination, a cross-validation study by multimodality approaches was followed: mAT-MASC were isolated from male mice expressing constitutively eGFP, which was detectable using techniques of immunofluorescence and qPCR. Y-chromosome positive cells, injected into wild-type female recipients, were detected by FISH. Cross-validation confirmed the data obtained by in vivo/ex vivo TD optical imaging analysis. In summary, our data demonstrates the usefulness of NIR TD optical imaging in tracking delivered cells, giving insights into the migratory properties of the injected cells