Anti-inflammatory coating of hernia repair meshes: a 5-rabbit study.

PURPOSE: Polymeric mesh implantation has become the golden standard in hernia repair, which nowadays is one of the most frequently performed surgeries in the world. However, many biocompatibility issues remain to be a concern for hernioplasty, with chronic pain being the most notable post-operative complication. Oxidative stress appears to be a major factor in the development of those complications. Lack of material inertness in vivo and oxidative environment formed by inflammatory cells result in both mesh deterioration and slowed healing process. In a pilot in vivo study, we prepared and characterized polypropylene hernia meshes with vitamin E (α-tocopherol)-a potent antioxidant. The results of that study supported the use of vitamin E as potential coating to alleviate post-surgical inflammation, but the pilot nature of the study yielded limited statistical data. The purpose of this study was to verify the observed trend of the pilot study statistically. METHODS: In this work, we conducted a 5-animal experiment where we have implanted vitamin E-coated and uncoated control meshes into the abdominal walls of rabbits. Histology of the mesh-adjacent tissues and electron microscopy of the explanted mesh surface were conducted to characterize host tissue response to the implanted meshes. RESULTS: As expected, modified meshes exhibited reduced foreign body reaction, as evidenced by histological scores for fatty infiltrates, macrophages, neovascularization, and collagen organization, as well as by the surface deterioration of the meshes. CONCLUSION: In conclusion, results indicate that vitamin E coating reduces inflammatory response following hernioplasty and protects mesh material from oxidative deterioration.

[The vitamin D sufficiency in children with recurrent bronchitis].

UNLABELLED: Currently in the world there is no consensus on the provision of sufficient vitamin D and its optimum serum levels of both healthy children and patients with various pathological conditions. THE OBJECTIVE: investigation of vitamin D sufficiency in children with recurrent bronchitis (RB), living in Zaporozhye, by examining of 25(OH)D and parathormone serum level. The study involved 120 children aged 4 to 10 years, divided into 2 groups (60 children each): 1) children, occasionally ill with acute respiratory infections, 2) children with RB. Investigation of serum 25(OH)D was conducted between November and February. Decrease of vitamin D3 below 30 ng/ml in serum was observed in 85% (р<0,05) patients with RB (insufficiency), below 20 ng/ml - in 15% (deficit). The children aged 4-10 years with RB, who living in Zaporozhye, have decrease of serum 25(OH)D that characterizes their vitamin D3 supply as insufficient.

A novel protocol allowing oral delivery of a protein complement inhibitor that subsequently targets to inflamed colon mucosa and ameliorates murine colitis.

While there is evidence of a pathogenic role for complement in inflammatory bowel disease, there is also evidence for a protective role that relates to host defence and protection from endotoxaemia. There is thus concern regarding the use of systemic complement inhibition as a therapeutic strategy. Local delivery of a complement inhibitor to the colon by oral administration would ameliorate such concerns, but while formulations exist for oral delivery of low molecular weight drugs to the colon, they have not been used successfully for oral delivery of proteins. We describe a novel pellet formulation consisting of cross-linked dextran coated with an acrylic co-polymer that protects the complement inhibitor CR2-Crry from destruction in the gastrointestinal tract. CR2-Crry containing pellets administered by gavage, were characterized using a therapeutic protocol in a mouse model of dextran sulphate sodium (DSS)-induced colitis. Oral treatment of established colitis over a 5-day period significantly reduced mucosal inflammation and injury, with similar therapeutic benefit whether or not the proton pump inhibitor, omeprazole, was co-administered. Reduction in injury was associated with the targeting of CR2-Crry to the mucosal surface and reduced local complement activation. Treatment had no effect on systemic complement activity. This novel method for oral delivery of a targeted protein complement inhibitor will reduce systemic effects, thereby decreasing the risk of opportunistic infection, as well as lowering the required dose and treatment cost and improving patient compliance. Furthermore, the novel delivery system described here may provide similar benefits for administration of other protein-based drugs, such as anti-tumour necrosis factor-α antibodies.

Electromechanical and elastic probing of bacteria in a cell culture medium.

Rapid phenotype characterization and identification of cultured cells, which is needed for progress in tissue engineering and drug testing, requires an experimental technique that measures physical properties of cells with sub-micron resolution. Recently, band excitation piezoresponse force microscopy (BEPFM) has been proven useful for recognition and imaging of bacteria of different types in pure water. Here, the BEPFM method is performed for the first time on physiologically relevant electrolyte media, such as Dulbecco's phosphate-buffered saline (DPBS) and Dulbecco's modified Eagle's medium (DMEM). Distinct electromechanical responses for Micrococcus lysodeikticus (Gram-positive) and Pseudomonas fluorescens (Gram-negative) bacteria in DPBS are demonstrated. The results suggest that mechanical properties of the outer surface coating each bacterium, as well as the electrical double layer around them, are responsible for the BEPFM image formation mechanism in electrolyte media.

Antibody-directed targeting of lysostaphin adsorbed onto polylactide nanoparticles increases its antimicrobial activity against S. aureus in vitro.

The objective of this paper was to study the effect of antibody-directed targeting of S. aureus by comparing the activities of lysostaphin conjugated to biodegradable polylactide nanoparticles (NPs) in the presence and in the absence of co-immobilized anti-S. aureus antibody. Lysostaphin-antibody-NP conjugates were synthesized through physical adsorption at different enzyme:antibody:NP ratios. The synthesized enzyme-NP conjugates were characterized by means of dynamic light scattering and zeta potential analysis, and the total protein binding yield on the NPs was characterized using Alexa Fluor 350 and 594 dyes for the S. aureus antibody and lysostaphin respectively. We observed enhanced antimicrobial activity for both enzyme-coated and enzyme-antibody-coated NPs for lysostaphin coatings corresponding to ∼ 40% of the initial monolayer and higher compared to the free enzyme case (p < 0.05). At the highest antibody coating concentration, bacterial lysis rates for antibody-coated samples were significantly higher than for lysostaphin-coated samples lacking the antibody (p < 0.05). Such enzyme-NP conjugates thus have the potential for becoming novel therapeutic agents for treating antibiotic-resistant S. aureus infections.

Protein-nanoparticle conjugates as potential therapeutic agents for the treatment of hyperlipidemia.

Hyperlipidemia, a condition associated with atherosclerosis, can develop because of the lack of low density lipoprotein (LDL) receptors in hepatocytes. Since injected polymeric nanoparticles are quickly taken up by the liver Kupffer cells, we hypothesize that it is possible to enhance LDL delivery to the liver through the use of LDL-absorbing nanoparticles. Here, we demonstrate the feasibility of the proposed approach in vitro. We used biodegradable and biocompatible polylactide nanoparticles (approximately 100 nm in diameter) with covalently attached apolipoprotein B100 antibody to adsorb LDLs at physiologically relevant concentrations. We showed that up to sixfold decreases of LDL levels can be achieved in vitro upon treatment of LDL suspensions (500 mg dl( - 1)) with anti-apoB100-nanoparticle conjugates. The study of the uptake of the antibody-nanoparticle-LDL complexes by cells was performed using a mouse macrophage cell line (RAW 264.7) as a model for liver Kupffer cells. We found that macrophages can quickly take up antibody-nanoparticle-LDL complexes and digest them within 24 h. No evidence of cytotoxicity was observed for the experimental conditions used in this study.

Double-layer mediated electromechanical response of amyloid fibrils in liquid environment.

Harnessing electrical bias-induced mechanical motion on the nanometer and molecular scale is a critical step toward understanding the fundamental mechanisms of redox processes and implementation of molecular electromechanical machines. Probing these phenomena in biomolecular systems requires electromechanical measurements be performed in liquid environments. Here we demonstrate the use of band excitation piezoresponse force microscopy for probing electromechanical coupling in amyloid fibrils. The approaches for separating the elastic and electromechanical contributions based on functional fits and multivariate statistical analysis are presented. We demonstrate that in the bulk of the fibril the electromechanical response is dominated by double-layer effects (consistent with shear piezoelectricity of biomolecules), while a number of electromechanically active hot spots possibly related to structural defects are observed.

Functional recognition imaging using artificial neural networks: applications to rapid cellular identification via broadband electromechanical response.

Functional recognition imaging in scanning probe microscopy (SPM) using artificial neural network identification is demonstrated. This approach utilizes statistical analysis of complex SPM responses at a single spatial location to identify the target behavior, which is reminiscent of associative thinking in the human brain, obviating the need for analytical models. We demonstrate, as an example of recognition imaging, rapid identification of cellular organisms using the difference in electromechanical activity over a broad frequency range. Single-pixel identification of model Micrococcus lysodeikticus and Pseudomonas fluorescens bacteria is achieved, demonstrating the viability of the method.

Effects of serum deprivation on the mechanical properties of adherent vascular smooth muscle cells.

Vascular smooth muscle cell (VSMC) function plays a key role in regulating the development and progression of vascular lesions. Among the more significant phenomena that occur during the development of these lesions is the phenotypic switching of VSMCs from a contractile to a synthetic state. A better understanding of the concurrent changes to VSMC mechanical properties that occur with phenotypic shifts can help to elucidate the role of VSMC mechanics in the development of vascular diseases. In the current study, the mechanical properties of adherent cultured rat aortic VSMCs were assessed by atomic force microscopy. Serum starvation was used to induce a phenotypic shift in vitro. It was concluded that serum starvation led to a statistically significant increase in apparent elastic modulus after 5 days, as well as a statistically significant decrease in hysteresis after culture for 3 days. If this trend of VSMC mechanical properties changing concurrently with phenotypic shifts were to hold true in vivo, such changes could affect the processes of mechanotransduction and/or arterial mechanical properties, thereby contributing to the progression of vascular disease.