Comparison of the linking arm effect on the biological performance of a CD31 agonist directly grafted on L605 CoCr alloy by a plasma-based multistep strategy.

Stents are cardiovascular implants deployed on atherosclerotic arteries that aid in reopening, sustaining, and avoiding their collapse. Nevertheless, postimplantation complications exist, and the risk of the renewal of the plaque subsists. Therefore, enhanced properties are mandatory requirements for clinics. For that purpose, a novel approach allowing the direct-grafting of bioactive molecules on cobalt-chromium devices (L605) has been developed. This original strategy involves the direct plasma functionalization of metallic surfaces with primary amines (-NH2). These groups act as anchor points to covalently graft biomolecules of interest, herein a peptide derived from CD31 (P23) with proendothelialization and antithrombotic properties. However, the biological activity of the grafted peptide could be impacted by its conformation. For this study, glutaric anhydride (GA), a short chain spacer, and polyethylene glycol (PEG) with antifouling properties were used as linking arms (LAs). The covalent grafting of the CD31 agonist on L605 by different LAs (GA-P23 and PEG-P23) was confirmed by XPS and ToF-SIMS analyses. The biological performance of these functionalized surfaces showed that, compared to the electropolished (EP) alloy, grafting the P23 with both LA increases adhesion and proliferation of endothelial cells (ECs) since day 1: EP = 68 ± 10%, GA-P23 = 101 ± 7%, and PEG-P23 = 106 ± 5% of cell viability. Moreover, ECs formed a complete monolayer at the surface, preventing clot formation (hemoglobin-free >80%). The potential of this plasma-based strategy for cardiovascular applications was confirmed by promoting a fast re-endothelialization, by improving the hemocompatibility of the alloy when coupled with the CD31 agonist and by its transfer onto commercial L605 stents, as confirmed by ToF-SIMS.

Specific IgG response against Mycobacterium avium paratuberculosis in children and adults with Crohn's disease.

BACKGROUND AND AIMS: Presence of serum antibodies against Mycobacterium avium paratuberculosis (MAP) in Crohn's Disease (CD) as a disease characteristic remains controversial. In the present work, we assessed antibody reactivity of serum and intestinal fluid against four distinct MAP-antigens, including the recently identified MAP-specific lipopentapeptide (L5P). METHODS: Immunoglobulin concentrations and specificity against 3 non MAP-specific antigens: glycosyl-transferase-d (GSD), purified protein derivative from MAP (Johnin-PPD), heparin binding haemagglutinin (MAP-HBHA) and one MAP-specific antigen: synthetic L5P were determined by ELISA in gut lavage fluids from adult controls or patients with CD, and in sera of children or adult controls or patients with CD, ulcerative colitis or celiac disease. RESULTS: Total IgA and IgG concentrations were increased in sera of children with CD but were decreased in sera of adults with CD, thereof specificity against MAP antigens was assessed by normalizing immunoglobulin concentrations between samples. In CD patients, IgG reactivity was increased against the four MAP antigens, including L5P in gut lavage fluids but it was only increased against L5P in sera. By contrast, anti-L5P IgG were not increased in patients with ulcerative colitis or celiac disease. CONCLUSIONS: A significant increase in anti-L5P IgG is observed in sera of children and adults with CD but not in patients with other intestinal inflammatory diseases. Anti-L5P antibodies may serve as serological marker for CD.