Statin Use and Markers of Immunity in the Doetinchem Cohort Study

It has been suggested that statins can both stimulate and suppress the immune system, and thereby, may influence autoimmune diseases. Therefore, we studied effects of statins on innate and adaptive immunity, and self-tolerance by measuring serological levels of C-reactive protein (CRP), neopterin, immunoglobulin E (IgE) antibodies and the presence of autoantibodies (antinuclear antibodies (ANA) and IgM rheumatoid factor (RF)) in the general population. We conducted a nested case-control study within the population-based Doetinchem cohort. Data from health questionnaires, serological measurements and information on medication from linkage to pharmacy-dispensing records were available. We selected 332 statin users (cases) and 331 non-users (controls), matched by age, sex, date of serum collection, history of cardiovascular diseases, diabetes mellitus type II and stroke. Multivariate regression analyses were performed to estimate effect of statins on the immune system. The median level of CRP in statin users (1.28 mg/L, interquartile range (IQR): 0.59-2.79) was lower than in non-users (1.62 mg/L, IQR: 0.79-3.35), which after adjustment was estimated to be a 28% lower level. We observed an inverse association between duration of statin use and CRP levels. Elevated levels of IgE (>100 IU/mL) were more prevalent in statin users compared to non-users. A trend towards increased levels of IgE antibodies in statin users was observed, whereas no associations were found between statin use and levels of neopterin or the presence of autoantibodies. In this general population sub-sample, we observed an anti-inflammatory effect of statin use and a trend towards an increase of IgE levels, an surrogate marker for Th (helper) 2 responses without a decrease in neopterin levels, a surrogate marker for Th1 response and/or self-tolerance. We postulate that the observed decreased inflammatory response during statin therapy may be important but is insufficient to induce loss of self-tolerance.     

PDE5 Inhibition Improves Object Memory in Standard Housed Rats but Not in Rats Housed in an Enriched Environment: Implications for Memory Models?

Drug effects are usually evaluated in animals housed under maximally standardized conditions. However, it is assumed that an enriched environment (EE) more closely resembles human conditions as compared to maximally standardized laboratory conditions. In the present study, we examined the acute cognition enhancing effects of vardenafil, a PDE5 inhibitor, which stimulates protein kinase G/CREB signaling in cells, in three different groups of male Wistar rats tested in an object recognition task (ORT). Rats were either housed solitarily (SOL) or socially (SOC) under standard conditions, or socially in an EE. Although EE animals remembered object information longer in the vehicle condition, vardenafil only improved object memory in SOL and SOC animals. While EE animals had a heavier dorsal hippocampus, we found no differences between experimental groups in total cell numbers in the dentate gyrus, CA2–3 or CA1. Neither were there any differences in markers for pre- and postsynaptic density. No changes in PDE5 mRNA- and protein expression levels were observed. Basal pCREB levels were increased in EE rats only, whereas β-catenin was not affected, suggesting specific activation of the MAP kinase signaling pathway and not the AKT pathway. A possible explanation for the inefficacy of vardenafil could be that CREB signaling is already optimally stimulated in the hippocampus of EE rats. Since previous data has shown that acute PDE5 inhibition does not improve memory performance in humans, the use of EE animals could be considered as a more valid model for testing cognition enhancing drugs.     

Population-based meta-analysis in Caucasians confirms association with COL5A1 and ZNF469 but not COL8A2 with central corneal thickness

Central corneal thickness (CCT) has become an endophenotype of major interest for the genetically complex disorder glaucoma. CCT has a high heritability, and thin CCT is an independent risk factor for the diagnosis and progression of open-angle glaucoma. Genome-wide association studies thus provide genetic loci associated with CCT and potentially related to open-angle glaucoma. The distribution of CCT and prevalence of glaucoma in population-based studies have demonstrated ethnic differences suggesting ethnic-dependent variations in the genetic determinants of CCT. We conducted a genome-wide association study in Caucasians (n?=?3,931) from the Gutenberg Health Study (Germany) followed by replication of 30 genome-wide significant SNPs or SNPs of interest (P?<?10^?5) in the Rotterdam Study (The Netherlands, n?=?1,418). In a combined analysis, we confirmed quantitative trait loci on chromosomes 9q34 and 16q24 for association with CCT. On chromosome 16q24, the locus is located in an intergenic region near the ZNF469 gene (top SNP: rs9938149, P?=?1.45?×?10^?12). ZNF469 missense mutation is involved in a syndrome with very thin cornea (brittle cornea syndrome). The second locus on chromosome 9q34 represents the intergenic region between the RXRA and COL5A1 gene (top SNP: rs3132306, P?=?2.71?×?10^?10). Collagen type 5 determines the diameter of the corneal collagen fibrils. In our Caucasian population-based GWA study, we reinforce the involvement of collagen-related genes influencing CCT in Caucasians. We could not confirm the collagen type 8 locus on chromosome 1 as reported in Asian studies.     

Solubilization of V-ATPase transmembrane peptides by amphipol A8-35.

Two transmembrane peptides encompassing the seventh transmembrane section of subunit a from V-ATPase from Saccharomyces cerevisiae were studied as complexes with APols A8-35 by CD and fluorescence spectroscopy, with the goal to use APols to provide a membrane-mimicking environment for the peptides. CD spectroscopy was used to obtain the overall secondary structure of the peptides, whereas fluorescence spectroscopy provided information about the local environment of their tryptophan residues. The fluorescence results indicate that both peptides are trapped by APols and the CD results that they adopt a beta-sheet conformation. This result is in contrast with previous work that showed that the same peptides are alpha-helical in SDS micelles and organic solvents. These observations are discussed in the context of APol physical-chemical properties and transmembrane peptide structural propensity.     

Complement factor C5a mediates renal ischemia-reperfusion injury independent from neutrophils

The complement system has been shown to mediate renal ischemia-reperfusion (I/R) injury. However, the contribution of complement factor C5a to I/R injury, in particular in the kidney, remains to be established. In this study, we investigated the impact of blocking the C5aR pathway on the inflammatory response and on the renal function in a murine model of I/R injury. First, we analyzed C5aR expression in kidneys of healthy mice. Intriguingly, we found expression on mesangial, as well as on tubular epithelial, cells. After I/R injury, C5aR expression was up-regulated in tubular epithelial cells. In addition, mRNA levels of CXC chemokines and TNF-alpha increased significantly and kidneys were heavily infiltrated by neutrophils. Blocking the C5aR pathway by a specific C5a receptor antagonist (C5aRA) abrogated up-regulation of CXC chemokines but not of TNF-alpha and reduced neutrophil infiltration by >50%. Moreover, application of the C5aRA significantly reduced loss of renal function. This improvement of function was independent of the presence of neutrophils because neutrophil depletion by mAb NIMP-R14 did not affect the protective effect of C5aRA treatment. Furthermore, blocking of the C5aR pathway had no influence on renal apoptosis. These data provide evidence that C5a is crucially involved in the pathogenesis of renal I/R injury by modulation of neutrophil-dependent as well as neutrophil-independent pathways, which include the regulation of CXC chemokines but not TNF-alpha or apoptotic pathways.     

Membrane assembly of M13 major coat protein: evidence for a structural adaptation in the hinge region and a tilted transmembrane domain

New insights into the low-resolution structure of the hinge region and the transmembrane domain of the membrane-bound major coat protein of the bacteriophage M13 are deduced from a single cysteine-scanning approach using fluorescence spectroscopy. New mutant coat proteins are labeled and reconstituted into phospholipid bilayers with varying headgroup compositions (PC, PE, and PG) and thicknesses (14:1PC, 18:1PC, and 22:1PC). Information about the polarity of the local environment around the labeled sites is deduced from the wavelength of maximum emission using AEDANS attached to the SH groups of the cysteines as a fluorescent probe. It is found that the protein is almost entirely embedded in the membrane, whereas the phospholipid headgroup composition of the membrane hardly affects the overall embedment of the protein in the membrane. From the assessment of a hydrophobic and hydrophilic face of the transmembrane helix, it is concluded that the helix is tilted with respect to the membrane normal. As compared to the thicker 18:1PC and 22:1PC membranes, reconstitution of the protein in the thin 14:1PC membranes results in a loss of helical structure and in the formation of a stretched conformation of the hinge region. It is suggested that the hinge region acts as a flexible spring between the N-terminal amphipathic arm and transmembrane hydrophobic helix. On average, the membrane-bound state of the coat protein can be seen as a gently curved and tilted, "banana-shaped" molecule, which is strongly anchored in the membrane-water interface at the C-terminus. From our experiments, we propose a rather small conformational adaptation of the major coat protein as the most likely reversible mechanism for responding to environmental changes during the bacteriophage disassembly and assembly process.     

Amplification of the groESL operon in Pseudomonas putida increases siderophore gene promoter activity

Molecular Genetics and Genomics - Pseudobactin 358 is the yellow-green fluorescent siderophore [microbial iron(III) transport agent] produced by Pseudomonas putida WCS358 under iron-limiting...     

Do personal computers make doctors less personal?

Ten months after the installation of a computer in a general practice surgery a postal survey (piloted questionnaire) was sent to 390 patients. The patients'' views of their relationship with their doctor after the computer was introduced were compared with their view of their relationship before the installation of the computer. More than 96% of the patients (n=263) stated that contact with their doctor was as easy and as personal as before. Most stated that the computer did not influence the duration of the consultation. Eighty one patients (30%) stated, however, that they thought that their privacy was reduced.Unlike studies of patients'' attitudes performed before any actual experience of use of a computer in general practice, this study found that patients have little difficulty in accepting the presence of a computer in the consultation room. Nevertheless, doctors should inform their patients about any connections between their computer and other, external computers to allay fears about a decrease in privacy.