p22phox C242T SNP inhibits inflammatory oxidative damage to endothelial cells and vessels

Background— T NADPH oxidase, by generating reactive oxygen species, is involved in the pathophysiology of many cardiovascular diseases and represents a therapeutic target for the development of novel drugs. A single-nucleotide polymorphism (SNP) C242T of the p22phox subunit of NADPH oxidase has been reported to be negatively associated with coronary heart disease (CHD) and may predict disease prevalence. However, the underlying mechanisms remain unknown. Methods and Results— Using computer molecular modelling we discovered that C242T SNP causes significant structural changes in the extracellular loop of p22phox and reduces its interaction stability with Nox2 subunit. Gene transfection of human pulmonary microvascular endothelial cells showed that C242T p22phox reduced significantly Nox2 expression but had no significant effect on basal endothelial O2.- production or the expression of Nox1 and Nox4. When cells were stimulated with TNFα (or high glucose), C242T p22phox inhibited significantly TNFα-induced Nox2 maturation, O2.- production, MAPK and NFκB activation and inflammation (all p<0.05). These C242T effects were further confirmed using p22phox shRNA engineered HeLa cells and Nox2-/- coronary microvascular endothelial cells. Clinical significance was investigated using saphenous vein segments from non CHD subjects after phlebectomies. TT (C242T) allele was common (prevalence of ~22%) and compared to CC, veins bearing TT allele had significantly lower levels of Nox2 expression and O2.- generation in response to high glucose challenge. Conclusions— C242T SNP causes p22phox structural changes that inhibit endothelial Nox2 activation and oxidative response to TNFα or high glucose stimulation. C242T SNP may represent a natural protective mechanism against inflammatory cardiovascular diseases.

Omega-3 polyunsaturated fatty acids and human health outcomes

Current intakes of very long chain omega-3 fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DNA) are low in most individuals living in Western countries. A good natural source of these fatty acids is seafood, especially oily fish. Fish oil capsules contain these fatty acids too. Very long chain w-3 fatty acids are readily incorporated from capsules into transport, functional, and storage pools. This incorporation is dose-dependent and follows a kinetic pattern that is characteristic for each pool. At sufficient levels of incorporation, EPA and DHA influence the physical nature of cell membranes and membrane protein-mediated responses, eicosanoid generation, cell signaling and gene expression in many different cell types. Through these mechanisms, EPA and DHA influence cell and tissue physiology, and the way cells and tissues respond to external signals. In most cases, the effects seen are compatible with improvements in disease biomarker profiles or in health-related outcomes. As a result, very long chain omega-3 fatty acids play a role in achieving optimal health and in protection against disease. Long chain omega-3 fatty acids protect against cardiovascular morbidity and mortality, and might be beneficial in rheumatoid arthritis, inflammatory bowel diseases, childhood learning, and behavior, and adult psychiatric and neurodegenerative illnesses. DHA has an important structural role in the eye and brain, and its supply early in life is known to be of vital importance. On the basis of the recognized health improvements brought about by long chain omega-3 fatty acids, recommendations have been made to increase their intake. (C) 2009 International Union of Biochemistry and Molecular Biology, Inc. Volume 35, Number 3, May/June 2009, Pages 266-272. E-mail: pcc@soton.ac.uk

Patients' attitudes towards, and information needs in relation to, nurse prescribing in rheumatology

Aims and objectives: To assess the level of confidence that rheumatology patients would have in nurse prescribing, the effects on likely adherence and particular concerns that these patients have. In addition, given that information provision has been cited as a potential benefit of nurse prescribing, the present study assessed the extent to which these patients would want an explanation for the selected medicine, as well as which types of information should be included in such an explanation. Background: Nurse prescribing has been successfully implemented in the UK in several healthcare settings. Existing research has not addressed the effects on patients' confidence and likely adherence, nor have patients' information needs been established. However, we know that inadequate medicines information provision by health professionals is one of the largest causes of patient dissatisfaction. Methods: Fifty-four patients taking disease-modifying drugs for inflammatory joint disease attending a specialist rheumatology clinic self-completed a written questionnaire. Results: Patients indicated a relatively high level of confidence in nurse prescribing and stated that they would be very likely to take the selected medication. The level of concern was relatively low and the majority of concerns raised did not relate to the nurse's status. Strong support was expressed for the nurse providing an explanation for medicine choice. Conclusion: This research provides support for the prescription of medicines by nurses working in the area of rheumatology, the importance of nurses providing a full explanation about the selected medicines they prescribe for these patients and some indication as to which categories of information should be included. Relevance to clinical practice: Rheumatology patients who have not yet experienced nurse prescribing are, in general, positive about nurses adopting this role. It is important that nurses provide appropriate information about the prescribed medicines, in a form that can be understood.

Biological significance of short-chain fatty acid metabolism by the intestinal microbiome

Purpose of review Evidence suggests that short-chain fatty acids (SCFAs) derived from microbial metabolism in the gut play a central role in host homeostasis. The present review describes the current understanding and physiological implications of SCFAs derived from microbial metabolism of nondigestible carbohydrates. Recent findings Recent studies indicate a role for SCFAs, in particular propionate and butyrate, in the metabolic and inflammatory disorders such as obesity, diabetes and inflammatory bowel diseases, through the activation of specific G-protein-coupled receptors and modification of transcription factors. Established prebiotics, such as fructooligosaccharides and galactooligosaccharides, which support the growth of Bifidobacteria, mainly mediate acetate production. Thus, recent identification of prebiotics which are able to stimulate the production of propionate and butyrate by benign saccharolytic populations in the colon is of interest. Summary Manipulation of saccharolytic fermentation by prebiotic substrates is beginning to provide information on structure–function relationships relating to the production of SCFAs, which have multiple roles in host homeostasis.

Fitting models for the joint action of two drugs using SAS(R)

Combinations of drugs are increasingly being used for a wide variety of diseases and conditions. A pre-clinical study may allow the investigation of the response at a large number of dose combinations. In determining the response to a drug combination, interest may lie in seeking evidence of synergism, in which the joint action is greater than the actions of the individual drugs, or of antagonism, in which it is less. Two well-known response surface models representing no interaction are Loewe additivity and Bliss independence, and Loewe or Bliss synergism or antagonism is defined relative to these. We illustrate an approach to fitting these models for the case in which the marginal single drug dose-response relationships are represented by four-parameter logistic curves with common upper and lower limits, and where the response variable is normally distributed with a common variance about the dose-response curve. When the dose-response curves are not parallel, the relative potency of the two drugs varies according to the magnitude of the desired effect and the models for Loewe additivity and synergism/antagonism cannot be explicitly expressed. We present an iterative approach to fitting these models without the assumption of parallel dose-response curves. A goodness-of-fit test based on residuals is also described. Implementation using the SAS NLIN procedure is illustrated using data from a pre-clinical study. Copyright © 2007 John Wiley & Sons, Ltd.

The pro-inflammatory oxidant hypochlorous acid induces Bax-dependent mitochondrial permeabilisation and cell death through AIF-/EndoG-dependent pathways

At sites of chronic inflammation, such as in the inflamed rheumatoid joint, activated neutrophils release hydrogen peroxide (H2O2) and the enzyme myeloperoxidase to catalyse the formation of hypochlorous acid (HOCl). 3-chlorotyrosine, a marker of HOCl in vivo, has been observed in synovial fluid proteins from rheumatoid arthritis patients. However the mechanisms of HOCl-induced cytotxicity are unknown. We determined the molecular mechanisms by which HOCl induced cell death in human mesenchymal progenitor cells (MPCs) differentiated into a chondrocytic phenotype as a model of human cartilage cells and show that HOCl induced rapid Bax conformational change, mitochondrial permeability and release of intra-mitochondrial pro-apoptotic proteins which resulted in nuclear translocation of AIF and EndoG. siRNA-mediated knockdown of Bax substantially prevented mitochondrial permeability, release of intra-mitochondrial pro-apoptotic proteins. Cell death was inhibited by siRNA-mediated knockdown of Bax, AIF or EndoG. Although we observed several biochemical markers of apoptosis, caspase activation was not detected either by western blotting, fluorescence activity assays or by using caspase inhibitors to inhibit cell death. This was further supported by findings that (1) in vitro exposure of recombinant human caspases to HOCl caused significant inhibition of caspase activity and (2) the addition of HOCl to staurosporine-treated MPCs inhibited the activity of cellular caspases. Our results show for the first time that HOCl induced Bax-dependent mitochondrial permeability which led to cell death without caspase activity by processes involving AIF/EndoG-dependent pathways. Our study provides a novel insight into the potential mechanisms of cell death in the inflamed human joint. (c) 2006 Elsevier Inc. All rights reserved.

Inducible hydrogen sulfide synthesis in chondrocytes and mesenchymal progenitor cells: is H2S a novel cytoprotective mediator in the inflamed joint?

Hydrogen sulfide (H(2)S) has recently been proposed as an endogenous mediator of inflammation and is present in human synovial fluid. This study determined whether primary human articular chondrocytes (HACs) and mesenchymal progenitor cells (MPCs) could synthesize H(2)S in response to pro-inflammatory cytokines relevant to human arthropathies, and to determine the cellular responses to endogenous and pharmacological H(2)S. HACs and MPCs were exposed to IL-1β, IL-6, TNF-α and lipopolysaccharide (LPS). The expression and enzymatic activity of the H(2)S synthesizing enzymes cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE) were determined by Western blot and zinc-trap spectrophotometry, respectively. Cellular oxidative stress was induced by H(2)O(2), the peroxynitrite donor SIN-1 and 4-hydroxynonenal (4-HNE). Cell death was assessed by 3-(4,5-dimethyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Mitochondrial membrane potential (DCm) was determined in situ by flow cytometry. Endogenous H(2) S synthesis was inhibited by siRNA-mediated knockdown of CSE and CBS and pharmacological inhibitors D,L-propargylglycine and aminoxyacetate, respectively. Exogenous H(2)S was generated using GYY4137. Under basal conditions HACs and MPCs expressed CBS and CSE and synthesized H(2)S in a CBS-dependent manner, whereas CSE expression and activity was induced by treatment of cells with IL-1β, TNF-α, IL-6 or LPS. Oxidative stress-induced cell death was significantly inhibited by GYY4137 treatment but increased by pharmacological inhibition of H(2)S synthesis or by CBS/CSE-siRNA treatment. These data suggest CSE is an inducible source of H(2)S in cultured HACs and MPCs. H(2)S may represent a novel endogenous mechanism of cytoprotection in the inflamed joint, suggesting a potential opportunity for therapeutic intervention.

Targeting medication non-adherence behavior in selected autoimmune diseases: a systematic approach to digital health program development

Background 29 autoimmune diseases, including Rheumatoid Arthritis, gout, Crohn’s Disease, and Systematic Lupus Erythematosus affect 7.6-9.4% of the population. While effective therapy is available, many patients do not follow treatment or use medications as directed. Digital health and Web 2.0 interventions have demonstrated much promise in increasing medication and treatment adherence, but to date many Internet tools have proven disappointing. In fact, most digital interventions continue to suffer from high attrition in patient populations, are burdensome for healthcare professionals, and have relatively short life spans. Objective Digital health tools have traditionally centered on the transformation of existing interventions (such as diaries, trackers, stage-based or cognitive behavioral therapy programs, coupons, or symptom checklists) to electronic format. Advanced digital interventions have also incorporated attributes of Web 2.0 such as social networking, text messaging, and the use of video. Despite these efforts, there has not been little measurable impact in non-adherence for illnesses that require medical interventions, and research must look to other strategies or development methodologies. As a first step in investigating the feasibility of developing such a tool, the objective of the current study is to systematically rate factors of non-adherence that have been reported in past research studies. Methods Grounded Theory, recognized as a rigorous method that facilitates the emergence of new themes through systematic analysis, data collection and coding, was used to analyze quantitative, qualitative and mixed method studies addressing the following autoimmune diseases: Rheumatoid Arthritis, gout, Crohn’s Disease, Systematic Lupus Erythematosus, and inflammatory bowel disease. Studies were only included if they contained primary data addressing the relationship with non-adherence. Results Out of the 27 studies, four non-modifiable and 11 modifiable risk factors were discovered. Over one third of articles identified the following risk factors as common contributors to medication non-adherence (percent of studies reporting): patients not understanding treatment (44%), side effects (41%), age (37%), dose regimen (33%), and perceived medication ineffectiveness (33%). An unanticipated finding that emerged was the need for risk stratification tools (81%) with patient-centric approaches (67%). Conclusions This study systematically identifies and categorizes medication non-adherence risk factors in select autoimmune diseases. Findings indicate that patients understanding of their disease and the role of medication are paramount. An unexpected finding was that the majority of research articles called for the creation of tailored, patient-centric interventions that dispel personal misconceptions about disease, pharmacotherapy, and how the body responds to treatment. To our knowledge, these interventions do not yet exist in digital format. Rather than adopting a systems level approach, digital health programs should focus on cohorts with heterogeneous needs, and develop tailored interventions based on individual non-adherence patterns.