Barbara Wessner

Vitamin D3 down-regulates monocyte TLR expression and triggers hyporesponsiveness to pathogen-associated molecular patterns.

Toll‐like receptors (TLR) represent an ancient front‐line defence system that enables the host organism to sense the presence of microbial components within minutes. As inducers of inflammation, TLR act as important triggers of distinct entities such as sepsis or autoimmune disease exacerbation. We report here that vitamin D3 [1α,25‐dihydroxycholecalciferol, 1,25(OH)2D3] suppresses the expression of TLR2 and TLR4 protein and mRNA in human monocytes in a time‐ and dose‐dependent fashion. Despite 1,25(OH)2D3‐induced up‐regulation of CD14, challenge of human monocytes with either LPS or lipoteichoic acid resulted in impaired TNF‐α and procoagulatory tissue factor (CD142) production, emphasizing the critical role of TLR in the induction of inflammation. Moreover, reduced TLR levels in 1,25(OH)2D3‐treated phagocytes were accompanied by impaired NF‐κB/RelA translocation to the nucleus and by reduced p38 and p42/44 (extracellular signal‐regulated kinase 1/2) phosphorylation upon TLR‐ligand engagement. Both TLR down‐regulation and CD14 up‐regulation were substantially inhibited by the vitamin D receptor (VDR) antagonist ZK 159222, indicating that the immunomodulatory effect of 1,25(OH)2D3 on innate immunity receptors requires VDR transcription factor activation. Our data provide strong evidence that 1,25(OH)2D3 primes monocytes to respond less effectively to bacterial cell wall components in a VDR‐dependent mechanism, most likely due to decreased levels of TLR2 and TLR4.

Assessing the antioxidative status in critically ill patients.

Purpose of reviewOxidative stress is caused by a higher production of reactive oxygen and reactive nitrogen species or a decrease in endogenous protective antioxidative capacity. In all types of critical illness, such as sepsis, trauma, burn injury, acute pancreatitis, liver injury, severe diabetes, acute respiratory distress syndrome, AIDS and kidney failure, the occurrence of increased oxidative stress or a reduced antioxidative status is described. Whereas in the past, reactive oxygen and reactive nitrogen species were mainly known as harmful agents, recent investigations have given a new insight into the (patho)physiological importance of these substances as powerful messenger molecules involved in gene regulation, thereby enabling the synthesis of cytokines or adhesion molecules necessary for defending inflammatory processes. As shown in this review, there are numerous possibilities for the quantification of oxidative stress. Recent findingsSeveral investigations showed a close association of single or multiple parameters, such as total antioxidative capacity, lipid peroxidation, vitamins C and E, the activation of nuclear factor kappa B, and respiratory burst, with the patients outcome. However, no recommendation for a single parameter to be measured can be given because the assays described do not allow the definition of an overall ‘antioxidative status’ for patients. SummaryThe occurrence of oxidative stress in critically ill patients is associated with a poor prognosis. The measurement of a cluster of assays representative of the quantification of reactive species or of antioxidants may improve the usefulness of therapeutic intervention and increase knowledge of pathophysiological alterations.

GREEN TEA POLYPHENOL EXTRACT ATTENUATES ZYMOSAN-INDUCED NON-SEPTIC SHOCK IN MICE

ABSTRACT Multiple-organ failure (MOF) is defined as the progressive deterioration in function which occurs in several organs or systems in patients with septic shock, multiple trauma, severe burns, or pancreatitis. In the present study, we have investigated the effects of Green Tea extract (GTE) on the development of general inflammation caused by zymosan (500 mg/kg, administered i.p. as a suspension in saline) in mice. Organ failure and systemic inflammation in mice was assessed 18 hours after administration of zymosan and/or GTE and monitored for 12 days (for loss of body weight and mortality). Treatment of mice with GTE (25 mg/kg i.p., 1 and 6 hours after zymosan) attenuated the peritoneal exudation and the migration of polymorphonuclear cells (PMNs) caused by zymosan, GTE also attenuated the lung, liver and pancreatic injury and renal dysfunction caused by zymosan as well as the increase in myeloperoxidase (MPO) activity caused by zymosan in the lung and intestine. Immunohistochemical analysis for inducible nitric oxide synthase (iNOS), nitrotyrosine and poly(ADP-ribose) (PAR) revealed positive staining in lung and intestine tissues obtained from zymosan-treated mice. The degree of staining for nitrotyrosine, iNOS and PAR were markedly reduced in tissue sections obtained from zymosan-treated mice, which received GTE. In conclusion this study provides evidence, for the first time, that GTE attenuates the degree of zymosan induced generalized inflammation in mice.

Modulation of toll-like receptor 4 expression on human monocytes by tumor necrosis factor and interleukin-6: Tumor necrosis factor evokes lipopolysaccharide hyporesponsiveness, whereas interleukin-6 enhances lipopolysaccharide activity

Toll-like receptors (TLR) play a pivotal role in the innate immune response, and the expression levels of these receptors may reflect the sensitivity of immune cells to infections. The binding of lipopolysaccharide (LPS) to TLR-4 triggers human monocytes to produce cytokines, which play a dominant role in the inflammatory response, as can be observed during sepsis and after polytrauma. Here, we evaluated TLR-4 expression of isolated monocytes in the presence of tumor necrosis factor (TNF)-&agr;, interleukin (IL) 6, IL-8, and IL-10, and we investigated cellular activation of this treatment. TNF-&agr; significantly down-regulated TLR-4 mRNA expression after 6 h (100% vs. 38.5% ± 4%; P < 0.05). This down-regulation was followed by a dose- and time-dependent diminished expression of TLR-4 surface protein (100% vs. 8.0% ± 5%; P < 0.01). Forty-eight hours after TNF-&agr; treatment, a reduced nuclear factor (NF)-&kgr;B translocation and a diminished IL-6 secretion after LPS stimulation were found (100% vs. 42.0% ± 23%; P < 0.05). In contrast, IL-6 incubation upregulated TLR-4 cell surface protein (100% vs. 165.8% ± 24%; P < 0.05) and increased the ability to activate NF-&kgr;B and AP-1 after LPS stimulation. Stimulation with IL-8 or IL-10 had no significant effects. We conclude that not only LPS but also TNF-&agr; and IL-6 have the potency to regulate the immune response via TLR-4. Down-regulation of TLR-4 by TNF-&agr; is associated with LPS hyporeactivity for NF-&kgr;B formation, whereas upregulation of TLR-4 via IL-6 can increase the responsiveness of mononuclear phagocytes.

Enhancement of arsenic trioxide‐mediated apoptosis using docosahexaenoic acid in arsenic trioxide‐resistant solid tumor cells

It has been shown that the polyunsaturated fatty acid docosahexaenoic acid (DHA) can sensitize various tumor cells to reactive oxygen species (ROS)‐inducing anticancer agents. Recently, we demonstrated that DHA also enhances the apoptotic effect of clinically achievable concentrations (1–2 μM) of arsenic trioxide (As2O3) in several As2O3‐resistant human leukemic cell lines via a ROS‐dependent mechanism. The aim of the present study was to evaluate whether this combined effect of As2O3 and DHA is also applicable to As2O3‐resistant solid tumor cells. We have tested 12 different tumor cell lines, including MDA‐MB‐468, SK‐BR‐3, MCF‐7 (breast cancer), ES‐2, SKOV‐3 (ovarian cancer), HT‐29, SW‐620, LS‐174T (colon cancer), PC‐3 (prostate cancer), HeLa (cervical cancer), PANC‐1 (pancreatic cancer) and one primary melanoma cell line. With the exception of MDA‐MB‐468 and ES‐2, all cells were resistant to treatment with either As2O3 or DHA alone. However, combined treatment with As2O3 and DHA significantly reduced viability in 7 of the 10 As2O3‐resistant solid tumors tested. The cytotoxic effect of As2O3 and DHA was associated with the induction of apoptosis and a concomitant increase of intracellular lipid peroxidation products. Importantly, the combined effect of As2O3 and DHA was selectively toxic for malignant cells since no cytotoxic effect was observed in normal skin fibroblasts, human microvascular endothelial cells and peripheral blood mononuclear cells derived from healthy donors. Our data indicate that DHA may help to extend the therapeutic spectrum of As2O3 in the treatment of solid tumors since it may overcome de novo or acquired resistance to As2O3.

Resveratrol enhances exercise training responses in rats selectively bred for high running performance

High Capacity Runner (HCR) rats have been developed by divergent artificial selection for treadmill endurance running capacity to explore an aerobic biology-disease connection. The beneficial effects of resveratrol supplementation have been demonstrated in endurance running and the antioxidant capacity of resveratrol is also demonstrated. In this study we examine whether 12 weeks of treadmill exercise training and/or resveratrol can enhance performance in HCR. Indeed, resveratrol increased aerobic performance and strength of upper limbs of these rats. Moreover, we have found that resveratrol activated the AMP-activated protein kinase, SIRT1, and mitochondrial transcription factor A (p<0.05). The changes in mitochondrial fission/fusion and Lon protease/HSP78 levels suggest that exercise training does not significantly induce damage of proteins. Moreover, neither exercise training nor resveratrol supplementation altered the content of protein carbonyls. Changes in the levels of forkhead transcription factor 1 and SIRT4 could suggest increased fat utilization and improved insulin sensitivity. These data indicate, that resveratrol supplementation enhances aerobic performance due to the activation of the AMPK-SIRT1-PGC-1α pathway.

Neuromuscular electrical stimulation reduces skeletal muscle protein degradation and stimulates insulin-like growth factors in an age- and current-dependent manner: A randomized, controlled clinical trial in major abdominal surgical patients

Objective:To investigate the effect of neuromuscular electrical stimulation (NMES) on skeletal muscle metabolism after major abdominal surgery. Summary Background Data:Protein catabolism associated with surgical interventions leads to reduced muscle strength, increased clinical complications and prolonged convalescence. Immobilization is suggested as a major stimulus for muscle wasting. This study investigates the potency of NMES on skeletal muscle growth factors and degradation processes in surgical patients. Methods:This observer blind study included 26 patients after major abdominal surgery mainly due to cancer aged 60 ± 10 years. Starting on the first postoperative day, 1 randomly assigned thigh of each patient was treated on 4 consecutive days with NMES, whereas the other leg was used as sham-stimulated control. Thereafter, muscle biopsies from both legs were performed. Differences in mRNA level, protein expression, and enzyme activity between legs were analyzed by cross-over analysis of variance (Clinical Trial Registration Number: NCT00635440). Results:NMES significantly increased total RNA content and total sarcoplasmatic protein content. NMES significantly reduced ubiquitin-conjugated sarcoplasmatic proteins and proteasome activity. The mechano growth factor mRNA level correlated positively with the applied current and negatively with the body mass index of the patients. The increase in insulin like growth factor-1Ea mRNA after NMES correlated negatively with the age of the patients. Conclusions:This study shows that NMES significantly increases total RNA content and reduces protein degradation in postoperative patients. Moreover, the induction of growth factors by NMES reveals dependency on body mass index, age, and applied current. We conclude that NMES is a useful clinical tool to reduce protein catabolism in postoperative patients.

Effect of single and combined supply of glutamine, glycine, N-acetylcysteine, and R,S-α-lipoic acid on glutathione content of myelomonocytic cells

BACKGROUND & AIMS Several diseases are characterised by decreased glutathione (GSH) levels due to an enhanced formation of oxygen radicals. To increase GSH levels, the additional supply of GSH precursors was suggested. In this study we evaluated the potency of a single and combined administration of the GSH modulating substances glutamine (GLN), N-acetylcysteine (NAC), and glycine (GLY) as well as R,S-alpha-lipoic acid (LA) to enhance intracellular GSH content in a well-defined model system. RESULTS Exposure of myelomonocytic U937 cells for 24 h to GLN revealed a 1.5-fold enhancement of GSH levels with a concomitant decrease in the formation of reactive oxygen species and lipid peroxidation. Addition of NAC stimulated GSH formation only at subphysiological GLN levels. GLY enhanced GSH levels under GLN starvation, but caused a diminution of GSH content under optimal GLN supply. LA in combination with 2 mmol/l GLN evoked a 3.6-fold enhancement of GSH content compared to GLN starved cells. CONCLUSION These results demonstrate that the GSH content of U937 cells is dependent on the supply of GLN, NAC, LA, and GLY. Combinations of the single substances can enhance but also decrease the intracellular GSH content, which is of clinical importance when supplying GSH-modulating substances to patients.

Time course-dependent changes in the transcriptome of human skeletal muscle during recovery from endurance exercise: from inflammation to adaptive remodeling

Reprogramming of gene expression is fundamental for skeletal muscle adaptations in response to endurance exercise. This study investigated the time course-dependent changes in the muscular transcriptome after an endurance exercise trial consisting of 1 h of intense cycling immediately followed by 1 h of intense running. Skeletal muscle samples were taken at baseline, 3 h, 48 h, and 96 h postexercise from eight healthy, endurance-trained men. RNA was extracted from muscle. Differential gene expression was evaluated using Illumina microarrays and validated with qPCR. Gene set enrichment analysis identified enriched molecular signatures chosen from the Molecular Signatures Database. Three hours postexercise, 102 gene sets were upregulated [family wise error rate (FWER), P < 0.05], including groups of genes related with leukocyte migration, immune and chaperone activation, and cyclic AMP responsive element binding protein (CREB) 1 signaling. Forty-eight hours postexercise, among 19 enriched gene sets (FWER, P < 0.05), two gene sets related to actin cytoskeleton remodeling were upregulated. Ninety-six hours postexercise, 83 gene sets were enriched (FWER, P < 0.05), 80 of which were upregulated, including gene groups related to chemokine signaling, cell stress management, and extracellular matrix remodeling. These data provide comprehensive insights into the molecular pathways involved in acute stress, recovery, and adaptive muscular responses to endurance exercise. The novel 96 h postexercise transcriptome indicates substantial transcriptional activity potentially associated with the prolonged presence of leukocytes in the muscles. This suggests that muscular recovery, from a transcriptional perspective, is incomplete 96 h after endurance exercise involving muscle damage.

The effect of six months of elastic band resistance training, nutritional supplementation or cognitive training on chromosomal damage in institutionalized elderly

Increased DNA and chromosomal damage are linked to aging and age-related diseases like cardiovascular diseases, diabetes or cancer. Physical activity and an optimal status of micro- and macronutrients are known to reduce the incidence of MN, a marker for chromosomal instability and mutagenicity. Once older people reach a certain age they change from a home-living situation to an institutionalized situation, which is often accompanied by malnutrition, depression and inactivity. We conducted the current study to investigate the effect of a six month progressive resistance training (RT), with or without protein and vitamin supplementation (RTS) or cognitive training (CT) only, on chromosomal damage measured by the cytokinesis block micronucleus cytome assay in 97 Austrian institutionalized women and men (65-98years). All three intervention groups demonstrated a tendency of a reduced frequency of cells with MN (-15%) as well as for the total number of MN (-20%), however no significant time-effect was observed. Besides a significant increase in plasma B12 and red blood cell folate status, the six month change of B12 was negatively correlated with the six month change of the MN frequency in the RTS group (r=-0.584, p=0.009). Our results suggest that in this age group either physical or cognitive training may result in similar biochemical changes and therefore enhance resistance against genomic instability. Supplementation with the vitamins B12 and folic acid could contribute to reduced chromosomal damage in institutionalized elderly.