Antimicrobial peptide incorporated poly(2-hydroxyethyl methacrylate) hydrogels for the prevention of Staphylococcus epidermidis-associated biomaterial infections

The effectiveness of the antimicrobial peptide maximin-4, the ultrashort peptide H-Orn-Orn-Trp-Trp-NH(2) , and the lipopeptide C(12) -Orn-Orn-Trp-Trp-NH(2) in preventing adherence of pathogens to a candidate biomaterial were tested utilizing both matrix- and immersion-loaded poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogels. Antiadherent properties correlated to both the concentration released and the relative antimicrobial concentrations of each compound against Staphylococcus epidermidis ATCC 35984, at each time point. Immersion-loaded samples containing C(12) -Orn-Orn-Trp-Trp-NH(2) exhibited the lowest adherence profile for all peptides studied over 1, 4, and 24 h. The results outlined in this article show that antimicrobial peptides have the potential to serve as an important weapon against biomaterial associated infections. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.

Novel Protective Properties of IGFBP-3 Result in Enhanced Pericyte Ensheathment, Reduced Microglial Activation, Increased Microglial Apoptosis, and Neuronal Protection after Ischemic Retinal Injury

This study was conducted to determine the perivascular cell responses to increased endothelial cell expression of insulin-like growth factor binding protein-3 (IGFBP-3) in mouse retina. The contribution of bone marrow cells in the IGFBP-3-mediated response was examined using green fluorescent protein-positive (GFP(+)) adult chimeric mice subjected to laser-induced retinal vessel occlusion injury. Intravitreal injection of an endothelial-specific IGFBP-3-expressing plasmid resulted in increased differentiation of GF(P)+ hematopoietic stem cells (HSCs) into pericytes and astrocytes as determined by immunohistochemical analysis. Administration of IGFBP-3 plasmid to mouse pups that underwent the oxygen-induced retinopathy model resulted in increased pericyte ensheathment and reduced pericyte apoptosis in the developing retina. Increased IGFBP-3 expression reduced the number of activated microglial cells and decreased apoptosis of neuronal cells in the oxygen-induced retinopathy model. In summary, IGFBP-3 increased differentiation of GFP(+) HSCs into pericytes and astrocytes while increasing vascular ensheathment of pericytes and decreasing apoptosis of pericytes and retinal neurons. All of these cytoprotective effects exhibited by IGFBP-3 overexpression can result in a more stable retinal vascular bed. Thus, endothelial expression of IGFBP-3 may represent a physiologic response to injury and may represent a therapeutic strategy for the treatment of ischemic vascular eye diseases, such as diabetic retinopathy and retinopathy of prematurity. (Am J Pathol 2011, 178:1517-1524; DOI: 10.1016/j.ajpath.2010.12.031)

Secondary prevention in the clinical management of patients with cardiovascular diseases. Core components, standards and outcome measures for referral and delivery.

Despite major improvements in diagnostics and interventional therapies, cardiovascular diseases remain a major health care and socio-economic burden both in western and developing countries, in which this burden is increasing in close correlation to economic growth. Health authorities and the general population have started to recognize that the fight against these diseases can only be won if their burden is faced by increasing our investment on interventions in lifestyle changes and prevention. There is an overwhelming evidence of the efficacy of secondary prevention initiatives including cardiac rehabilitation in terms of reduction in morbidity and mortality. However, secondary prevention is still too poorly implemented in clinical practice, often only on selected populations and over a limited period of time. The development of systematic and full comprehensive preventive programmes is warranted, integrated in the organization of national health systems. Furthermore, systematic monitoring of the process of delivery and outcomes is a necessity. Cardiology and secondary prevention, including cardiac rehabilitation, have evolved almost independently of each other and although each makes a unique contribution it is now time to join forces under the banner of preventive cardiology and create a comprehensive model that optimizes long term outcomes for patients and reduces the future burden on health care services. These are the aims that the Cardiac Rehabilitation Section of the European Association for Cardiovascular Prevention & Rehabilitation has foreseen to promote secondary preventive cardiology in clinical practice.

Surface localisation of photosensitisers on intraocular lens biomaterials for prevention of infectious endophthalmitis and retinal protection

Cataract surgery is one of the most commonly-practiced surgical procedures in Western medicine, and, while complications are rare, the most serious is infectious postoperative endophthalmitis. Bacteria may adhere to the implanted intraocular lens (IOL) and subsequent biofilm formation can lead to a chronic, difficult to treat infection. To date, no method to reduce the incidence of infectious endophthalmitis through bacterial elimination, while retaining optical transparency, has been reported. In this study we report a method to optimise the localisation of a cationic porphyrin at the surface of suitable acrylate copolymers, which is the first point of contact with potential pathogens. The porphyrin catalytically generates short-lived singlet oxygen, in the presence of visible light, which kills adherent bacteria indiscriminately. By restricting the photosensitiser to the surface of the biomaterial, reduction in optical transparency is minimised without affecting efficacy of singlet oxygen production. Hydrogel IOL biomaterials incorporating either methacrylic acid (MAA) or methyl methacrylate (MMA) co-monomers allow tuning of the hydrophobic and anionic properties to optimise the localisation of porphyrin. Physiochemical and antimicrobial properties of the materials have been characterised, giving candidate materials with self-generating, persistent anti-infective character against Gram-positive and Gram-negative organisms. Importantly, incorporation of porphyrin can also serve to protect the retina by filtering damaging shortwave visible light, due to the Soret absorption (?max) 430 nm). © 2012 Elsevier Ltd. All rights reserved.