Anthracycline-induced cardiotoxicity: Overview of studies examining the roles of oxidative stress and free cellular iron

The risk of cardiotoxicity is the most serious drawback to the clinical usefulness of anthracycline antineoplastic antibiotics, which include doxorubicin (adriamycin), daunorubicin or epirubicin. Nevertheless, these compounds remain among the most widely used anticancer drugs. The molecular pathogenesis of anthracycline cardiotoxicity remains highly controversial, although the oxidative stress-based hypothesis involving intramyocardial production of reactive oxygen species (ROS) has gained the widest acceptance. Anthracyclines may promote the formation of ROS through redox cycling of their aglycones as well as their anthracycline-iron complexes. This proposed mechanism has become particularly popular in light of the high cardioprotective efficacy of dexrazoxane (ICRF-187). The mechanism of action of this drug has been attributed to its hydrolytic transformation into the iron-chelating metabolite ADR-925, which may act by displacing iron from anthracycline-iron complexes or by chelating free or loosely bound cellular iron, thus preventing site-specific iron-catalyzed ROS damage. However, during the last decade, calls for the critical reassessment of this “ROS and iron” hypothesis have emerged. Numerous antioxidants, although efficient in cellular or acute animal experiments, have failed to alleviate anthracycline cardiotoxicity in clinically relevant chronic animal models or clinical trials. In addition, studies with chelators that are stronger and more selective for iron than ADR-925 have also yielded negative or, at best, mixed outcomes. Hence, several lines of evidence suggest that mechanisms other than the traditionally emphasized “ROS and iron” hypothesis are involved in anthracycline-induced cardiotoxicity and that these alternative mechanisms may be better bases for designing approaches to achieve efficient and safe cardioprotection.     

Simultaneous Detection of 15 Human Cytokines in a Single Sample of Stimulated Peripheral Blood Mononuclear Cells

Cytokines secreted by cells of the immune system can alter the behavior and properties of immune or other cells. At a site of inflammation, sets of cytokines interact with immune cells, and their combined effect is often more important than the function of one isolated component. Conventional techniques, such as enzyme-linked immunosorbent assays, generally require large quantities of cells to characterize a complete cytokine profile of activated lymphocytes. The Bio-Plex system from Bio-Rad Laboratories combines the principle of a sandwich immunoassay with the Luminex fluorescent-bead-based technology. We developed a multiplex cytokine assay to detect different cytokines simultaneously in culture supernatant of human peripheral blood mononuclear cells stimulated with antigen and with mitogen. Fifteen human cytokines (interleukin 1α [IL-1α], IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, IL-15, IL-17, IL-18, gamma interferon, and tumor necrosis factor alpha) were validated with a panel of healthy individuals, rheumatoid arthritis patients, and juvenile idiopathic arthritis patients. Comparing the multiplex assay with a regular enzyme-linked immunosorbent assay technique with this donor panel resulted in correlation coefficients for all cytokines ranging from 0.75 to 0.99. Intra-assay variance proved to be less then 10%, whereas interassay variability ranged between 10 and 22%. This multiplex system proved to be a powerful tool in the quantitation of cytokines. It will provide a more complete picture in differences between activated lymphocyte cytokine profiles from healthy individuals and those from patients with chronic inflammatory diseases.     

Different levels of natural antibodies in chickens divergently selected for specific antibody responses

We studied the presence of Natural antibodies in plasma samples from individual birds from selected chicken lines at young and old age. Binding, specificity, and relative affinity to various antigens were determined in plasma from non-immunized female chickens at 5 weeks of age, and in plasma obtained from the same chickens one year later using indirect two-step ELISA. Birds were from three different lines. The lines were divergently selected for either high (H line) or low (L line) antibody titers to Sheep Red Blood Cells at 5 weeks of age, next to a random bred control (C line). Binding of plasma immunoglobulins (Ig) from all three lines was found with chicken-egg-white protein (CEP), ovalbumin (OVA), myoglobin (MYO), thyroglobulin (THYRO), keyhole limpet hemocyanin (KLH), bovine serum albumin (BSA), and transferrin (TRANS). Significantly higher binding to most antigens was found with plasma Ig from adult birds from the H line as compared to plasma Ig from the L line, whereas binding of plasma Ig from C-line birds was in between or similar to the H or L line, respectively. Binding of Ig to all antigens in all three lines was significantly higher in plasma obtained at one year of age as compared to plasma obtained at 5 weeks of age. A competitive ELISA with homologous and heterologous antigens was used for determining specificity of the antigen-binding antibodies. Nai;ve plasma samples were characterized by a broad binding to all antigens tested. Inhibition of binding to specific antigens was possible with a broad range of heterologous antigens, but highest competition of binding was obtained with homologous antigen. Both linear regression analysis of serial dilutions of the plasma Ig binding the antigens, as well as competitive ELISA with homologous antigen indicated that plasma Ig from the H line and plasma Ig from the L line had similar affinity characteristics to the antigens tested with the exception of OVA and KLH. Pooled non-immune plasma from H line birds bound to CEP, OVA, THYRO, TRANS, MYO, KLH, and salt-precipitated extracts and supernatants of extracts from chicken heart, spleen, liver, brain, bursa, thymus, and kidney, respectively, as determined by Western blotting. The increasing presence of antibodies in nai;ve chicken plasma binding heterologous and homologous (tissue) antigens indicates the presence of Natural antibodies in poultry. Apart from age, increasing levels of Natural antibodies may be related with the genetically based magnitude of specific antibody levels in the chicken lines studied.     

Temperature dependence of mutant mevalonate kinase activity as a pathogenic factor in hyper-IgD and periodic fever syndrome

Hyper-IgD and periodic fever syndrome (HIDS) and mevalonic aciduria are autosomal recessive disorders characterized by recurrent episodes of fever and generalized inflammation. Both syndromes are caused by specific mutations in the gene encoding mevalonate kinase (MK), resulting in a depressed enzymatic activity mainly due to reduced protein levels. We studied the effect of temperature on the activity of wild-type and several mutant MKs in fibroblasts. All fibroblast cell lines from HIDS patients and harbouring the common V377I MVK allele displayed substantially higher MK activities at 30 degrees C as compared to 37 degrees C. As shown by temperature inactivation experiments this resulted in a protein nearly as stable as in control cell lines, indicating that primarily the maturation of the protein is affected. Accordingly, when HIDS cell lines were cultured at 39 degrees C, MK activity decreased further. This triggered a compensatory increase in 3-hydroxy-3-methylglutaryl-CoA reductase activity, indicating that MK becomes progressively rate-limiting. A similar phenomenon occurs in vivo. MK activity in peripheral blood mononuclear cells drops 2-8-fold when HIDS patients experience febrile attacks. Our results suggest that minor elevations in temperature can set off a chain of events with MK becoming progressively rate-limiting, leading to a temporary deficiency of isoprenoid end-products, which induces inflammation and fever.     

Baseline immune activation as a risk factor for the onset of depression during interferon-alpha treatment.

BACKGROUND: Major depression has been associated cross-sectionally with increased cell-mediated immune activation but causality has been difficult to establish. This study prospectively investigated the hypothesis that baseline level of immune activation predicts the development of depression during interferon-alpha (IFN-alpha) treatment. METHODS: Sixteen hepatitis C patients without psychiatric disorder underwent IFN-alpha treatment. Proinflammatory and anti-inflammatory cytokines were determined before starting treatment. Presence of a major depressive disorder (MDD) was assessed at baseline and several times during treatment. RESULTS: Baseline soluble interleukin-2 receptor (sIL-2r), interleukin-6 (IL-6), and interleukin-10 (IL-10) concentrations were significantly increased in the five subjects that developed MDD during treatment compared with those that did not, with standardized effect sizes of 1.08, 1.16, and 1.25, respectively, controlling for marijuana use, cigarette smoking, and baseline level of depressive symptoms. CONCLUSIONS: Results suggest that increased immune activation, rather than an epiphenomenon, is a causal risk factor for the development of MDD.     

Outcomes of low-vision services using optometric and multidisciplinary approaches: a non-randomized comparison

Consecutive patients (n = 215) who were referred to optometric (55%) or multidisciplinary (45%) low-vision services and above 50 years of age were recruited from four hospitals in the Netherlands. They completed two vision-related quality of life questionnaires, the Vision Quality of Life Core Measure (VCM1) and the Low Vision Quality of Life Questionnaire (LVQOL), before their first visit with low-vision services and 1 year later. At follow-up, patients referred to multidisciplinary low-vision services had lower scores on the mobility subscale of the LVQOL than patients referred to optometric low-vision services [5.3 points; 95% confidence interval (CI): 0.2-10.5]. Paired sample t-tests for the two groups of patients taken together show improvement for the VCM1 (3.1 points; 95% CI: 0.6-5.6) and deterioration for the basic aspects of vision (3.5 points; 95% CI: 1.1-5.9) and the mobility (6.6 points; 95% CI: 3.7-9.5) subscales of the LVQOL. In conclusion, people referred to optometric services showed less deterioration in mobility than those referred to multidisciplinary services. No differences were observed for any of the other subscales of the LVQOL and the VCM1. Future research in this field should include randomized controlled designs comparing low-vision services with no treatment or placebo.     

Acute coronary syndromes

The first 150 words of the full text of this article appear below. Key points Coronary artery disease accounts for >30% ofdeaths in Western society. The diagnosis of myocardial infarctionshould be qualified by size, causation and time from occurrence. Mortalityis reduced by immediate or ‘primary’ percutaneouscoronary intervention or thrombolysis within the first 24 hof onset of ST-segment elevation myocardial infarction. Strategiesto reduce platelet activation (glycoprotein IIb/IIIa receptorantagonists, or clopidogrel) are now recommended in the treatmentof high-risk non-ST-segment myocardial infarction/unstable angina. Elevatedserum troponins may be the result of non-ischaemic myocardialdamage, especially in critical illness.