Anthrax Lethal Toxin Suppresses Murine Cardiomyocyte Contractile Function and Intracellular Ca2+ Handling via a NADPH Oxidase-Dependent Mechanism

OBJECTIVES: Anthrax infection is associated with devastating cardiovascular sequelae, suggesting unfavorable cardiovascular effects of toxins originated from Bacillus anthracis namely lethal and edema toxins. This study was designed to examine the direct effect of lethal toxins on cardiomyocyte contractile and intracellular Ca(2+) properties. METHODS: Murine cardiomyocyte contractile function and intracellular Ca(2+) handling were evaluated including peak shortening (PS), maximal velocity of shortening/ relengthening (± dL/dt), time-to-PS (TPS), time-to-90% relengthening (TR(90)), intracellular Ca(2+) rise measured as fura-2 fluorescent intensity (ΔFFI), and intracellular Ca(2+) decay rate. Stress signaling and Ca(2+) regulatory proteins were assessed using Western blot analysis. RESULTS: In vitro exposure to a lethal toxin (0.05-50 nM) elicited a concentration-dependent depression on cardiomyocyte contractile and intracellular Ca(2+) properties (PS, ± dL/dt, ΔFFI), along with prolonged duration of contraction and intracellular Ca(2+) decay, the effects of which were nullified by the NADPH oxidase inhibitor apocynin. The lethal toxin significantly enhanced superoxide production and cell death, which were reversed by apocynin. In vivo lethal toxin exposure exerted similar time-dependent cardiomyocyte mechanical and intracellular Ca(2+) responses. Stress signaling cascades including MEK1/2, p38, ERK and JNK were unaffected by in vitro lethal toxins whereas they were significantly altered by in vivo lethal toxins. Ca(2+) regulatory proteins SERCA2a and phospholamban were also differentially regulated by in vitro and in vivo lethal toxins. Autophagy was drastically triggered although ER stress was minimally affected following lethal toxin exposure. CONCLUSIONS: Our findings indicate that lethal toxins directly compromised murine cardiomyocyte contractile function and intracellular Ca(2+) through a NADPH oxidase-dependent mechanism

Identification of molecular pathways affected by pterostilbene, a natural dimethylether analog of resveratrol

<p>Abstract</p> <p>Background</p> <p>Pterostilbene, a naturally occurring phenolic compound produced by agronomically important plant genera such as <it>Vitis </it>and <it>Vacciunium</it>, is a phytoalexin exhibiting potent antifungal activity. Additionally, recent studies have demonstrated several important pharmacological properties associated with pterostilbene. Despite this, a systematic study of the effects of pterostilbene on eukaryotic cells at the molecular level has not been previously reported. Thus, the aim of the present study was to identify the cellular pathways affected by pterostilbene by performing transcript profiling studies, employing the model yeast <it>Saccharomyces cerevisiae</it>.</p> <p>Methods</p> <p><it>S. cerevisiae </it>strain S288C was exposed to pterostilbene at the IC₅₀concentration (70 μM) for one generation (3 h). Transcript profiling experiments were performed on three biological replicate samples using the Affymetrix GeneChip Yeast Genome S98 Array. The data were analyzed using the statistical methods available in the GeneSifter microarray data analysis system. To validate the results, eleven differentially expressed genes were further examined by quantitative real-time RT-PCR, and <it>S. cerevisiae </it>mutant strains with deletions in these genes were analyzed for altered sensitivity to pterostilbene.</p> <p>Results</p> <p>Transcript profiling studies revealed that pterostilbene exposure significantly down-regulated the expression of genes involved in methionine metabolism, while the expression of genes involved in mitochondrial functions, drug detoxification, and transcription factor activity were significantly up-regulated. Additional analyses revealed that a large number of genes involved in lipid metabolism were also affected by pterostilbene treatment.</p> <p>Conclusion</p> <p>Using transcript profiling, we have identified the cellular pathways targeted by pterostilbene, an analog of resveratrol. The observed response in lipid metabolism genes is consistent with its known hypolipidemic properties, and the induction of mitochondrial genes is consistent with its demonstrated role in apoptosis in human cancer cell lines. Furthermore, our data show that pterostilbene has a significant effect on methionine metabolism, a previously unreported effect for this compound.</p

Plant-derived modulators of inflammation and cartilage metabolism

Currently the treatment of chronic inflammatory diseases is aimed at inhibiting the symptoms of the disease since there are no curative or preventive treatments available. Rheumatoid arthritis (RA) is a painful chronic inflammatory disease of the joints. Osteoarthritis (OA) is a disease in which pain and inflammation of the joint in certain (end-) stages of the disease plays an important role. For variable reasons patients use natural products to relieve their symptoms, with many claims that have insufficient scientific evidence unfortunately. In this thesis a selection of phytochemicals and plant extracts was investigated for their potential modulating effects on inflammatory processes and on chondrocyte cartilage metabolism relevant for OA and RA. Most of these are suitable for nutritional purposes. Different test systems were used, ranging from in vitro experiments with both animal and human cells, to in vivo animal experiments. A bioavailability study in human healthy volunteers was performed as well. Among the tested flavonoids, apigenin, chrysin and luteolin eliminated monocytes/macrophages from white blood cells in vitro, whereas quercetin and naringenin had no effects. An extract of Pterocarpus marsupium demonstrated inhibitory activity of prostaglandin E2 (PGE2) which was related to the pterostilbene content of the extract. Moreover, from whole blood assays it became clear that it reduced PGE2 produced by cyclooxygenase (COX)-2 and not by COX-1. In a pilot study with human healthy volunteers the extract was not active. An extract of hop (Humulus lupulus) showed to inhibit PGE2 produced by COX-2 and not by COX-1. In an animal study for acute arthritis oral administration of the hop extract did not result in reduced joint swelling although it was bioavailable. Oral administration of apocynin was able to confirm two in vitro observed features in vivo: (1) oral administration of apocynin was able to reverse zymosan-induced inhibition of cartilage proteoglycan synthesis partially, and (2) oral administration of apocynin showed COX inhibitory effects similar to the NSAID ibuprofen. SKI306X, a preparation of a mix of three oriental plants (Clematis mandshurica, Trichosanthes kirilowii and Prunella vulgaris), has been studied in OA patients. The in vitro studies described in this thesis demonstrated that the biological effects of SKI306X are at least bipartite: (1) cartilage protective and (2) anti-inflammatory. In conclusion, the results from this thesis illustrate that there is a large potential of plant-derived components as anti-inflammatory agents. However, further research, which includes clinical trials in the relevant patient groups, has to elucidate whether these plant-derived components are appropriate candidates as anti-inflammatory agents suitable for nutritional purposes

Selective COX-2 inhibition by a Pterocarpus marsupium extract characterized by pterostilbene, and its activity in healthy human volunteers.

Contains fulltext : 48361.pdf (publisher's version ) (Open Access)In this study, an extract of Pterocarpus marsupium Roxb. containing pterostilbene has been evaluated for its PGE2-inhibitory activity in LPS-stimulated PBMC. In addition, the COX-1/2 selective inhibitory activity of P. marsupium (PM) extract was investigated. Biological activity, as well as safety of PM extract was evaluated in healthy human volunteers. PM extract, pterostilbene and resveratrol inhibited PGE2 production from LPS-stimulated human peripheral blood mononuclear cells (PBMC) with IC50 values of 3.2 +/- 1.3 microg/mL, 1.0 +/- 0.6 microM and 3.2 +/- 1.4 microM, respectively. When pterostilbene content of PM extract is calculated, PGE2 production inhibition of PM extract is comparable to PGE2 production inhibition of purified pterostilbene. Furthermore, in a COX-1 whole blood assay (WBA) PM extract was not effective while in a COX-2 WBA, PM extract decreased PGE2 production indicating COX-2 specific inhibition. In healthy human volunteers, the oral use of 450 mg PM extract did not decrease PGE2 production ex vivo in a WBA. Pterostilbene levels in serum were increased, but were 5-fold lower than the observed IC50 for PGE2 inhibition in LPS-stimulated PBMC. No changes from base-line of the safety parameters were observed and no extract-related adverse events occurred during the study. In conclusion, this is the first study to describe the selective COX-2 inhibitory activity of a Pterocarpus marsupium extract. Moreover, the PGE2 inhibitory activity of PM extract was related to its pterostilbene content. In humans, 450 mg PM extract resulted in elevated pterostilbene levels in serum, which were below the active concentration observed in vitro. In addition, short-term supplementation of 450 mg PM extract is considered to be a safe dose based on the long history of use, the absence of abnormal blood cell counts and blood chemistry values and the absence of extract-related adverse events. This strongly argues for a dose-finding study of PM extract in humans to corroborate the in vitro observed inhibitory activity on PGE2 production in order to resolve the potential use of PM extract in inflammatory disorders and/or inflammatory pain

Selective inhibition of COX-2 by a standardized CO2 extract of Humulus lupulus in vitro and its activity in a mouse model of zymosan-induced arthritis.

Item does not contain fulltextA standardized CO(2) extract from Humulus lupulus L. (hop extract) was investigated for its selective COX-1/2 inhibitory properties. An in vitro model of inflammation using lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (PBMC) was used as a model to investigate the effect of hop extract on PGE(2) production. COX-1/2 selective inhibition by the hop extract was investigated in a COX-1 whole blood assay (WBA) and a COX-2 WBA. To evaluate the in vivo activity of hop extract, it was administered orally to C57BL/6 mice in which inflammation of the right joint was induced by injecting zymosan intra-articularly. Ex vivo PGE(2) production of LPS-stimulated blood cells was determined. Also, the effect of hop extract on healthy and arthritic cartilage was investigated as well as effects on inflammatory joint swelling. Hop extract inhibited PGE(2) production by LPS-stimulated PBMC without compromising the metabolic activity of these cells. Furthermore, hop extract showed a decline in PGE(2) production in the COX-2 whole blood assay (WBA) with an IC(50) of 20.4 microg/mL, while in the COX-1 WBA no inhibition of PGE(2) production was observed. This indicates a COX-2 selective inhibition. The COX-1 inhibitor SC-560 inhibited PGE(2) production in the COX-1 WBA but not in the COX-2 WBA. At 2 microM, celecoxib inhibited PGE(2) production in the COX-2 WBA by 92 % and in the COX-1 WBA by 50 %. When hop extract was administered orally to C57BL/6 mice in which joint inflammation was induced with zymosan, PGE(2) production in ex vivo LPS-stimulated whole blood was significantly decreased by 24 %, suggesting that hop extract becomes bioavailable. Furthermore, oral administration of hop extract showed no negative or positive effects on healthy cartilage proteoglycan synthesis, or on zymosan-induced arthritic cartilage proteoglycan synthesis. However, no effect of oral administration of 1.25 mg hop extract daily was observed on joint swelling. In conclusion, this standardized CO(2) extract of Humulus lupulus could be a useful agent for intervention strategies targeting inflammatory disorders and/or inflammatory pain

Multiple acute temperature stress affects leucocyte populations and antibody responses in common carp, Cyprinus carpio L

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PP064-SUN EFFECTS OF NUTRITIONAL INTERVENTION ON IMMUNE MARKERS IN MALNOURISHED ELDERLY

Rationale: Both malnutrition and advanced age are known to negatively impact the immune system. This exploratory randomized controlled trial studied the effects of a composed nutritional intervention on immune markers, endocrine markers and a selection of micronutrients in malnourished ill elderly patients. Methods: Malnourished elderly patients (>60) newly admitted to a university medical center were randomised to receive either usual care plus a nutritional intervention (energy and protein enriched diet, comprising oral nutritional support, calcium-vitamin D supplement, dietetary counselling) commencing in the hospital and continued for 3 months post-discharge or usual care alone. Immune markers (interleukins, complement, C-reactive protein, albumin, TNF-alpha), endocrine markers (growth factors) and micronutrients (iron, ferritin, vitamin A, E and D), were measured at baseline and at 3 months following hospital discharge. Results: 210 patients were included in this study. For 89 patients (46 intervention, 43 control) both measurements were available. This selection of patients were in a better health status compared to the total group. At baseline, most of the analysed immune markers, endocrine markers and micronutrients showed values within the normal range, with no statistically significant differences between groups. The majority of immune markers, endocrine markers and micronutrients tended to improve over time, without statistically significant differences between groups, except for vitamin D (p = 0.008), confirming the supplementation in the intervention group. Conclusion: A 3 months nutritional intervention in malnourished ill elderly patients could not demonstrate measurable additional influence on measured immune markers, endocrine markers and selected micronutrients at three months compared to baseline. The improved outcomes were presumably caused by patients' improved health status during time

Decreased pro-inflammatory cytokine production by LPS-stimulated PBMC upon in vitro incubation with the flavonoids apigenin, luteolin or chrysin, due to selective elimination of monocytes/macrophages.

Contains fulltext : 47688.pdf (publisher's version ) (Closed access)Apigenin and its structural analogues chrysin and luteolin were used to evaluate their capacity to inhibit the production of pro-inflammatory cytokines by lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (PBMC). Furthermore, flowcytometric analysis was performed to compare the effects of apigenin, chrysin, luteolin, quercetin and naringenin on the different cell types present in PBMC. LPS-stimulated PBMC were cultured in the presence of the flavonoids and TNFalpha, IL-1beta and IL-6 were measured in the supernatants. In parallel, metabolic activity of the PBMC was determined by measuring succinate dehydrogenase activity. Apigenin, chrysin and luteolin dose-dependently inhibited both pro-inflammatory cytokine production and metabolic activity of LPS-stimulated PBMC. With increasing concentration of apigenin, chrysin or luteolin the monocytes/macrophages disappeared as measured by flowcytometry. This also appeared to occur in the non-LPS-stimulated PBMC. At the same time there was an increase in dead cells. T- and B-lymphocytes were not affected. Quercetin and naringenin had virtually no effects on cytokines, metabolic activity or on the number of cells in the studied cell populations. In conclusion, monocytes were specifically eliminated in PBMC by apigenin, chrysin or luteolin treatment in vitro at low concentrations (around 8 microM), in which apigenin appeared to be the most potent