Antimicrobial promotion of pig growth is associated with tissue-specific remodeling of bile acid signature and signaling

The spread of bacterial resistance to antimicrobials (AMA) have intensified efforts to discontinue the non-therapeutic use of AMA in animal production. Finding alternatives to AMA, however, is currently encumbered by the obscure mechanism that underlies their growth-promoting action. In this report, we demonstrate that combinations of antibiotics and zinc oxide at doses commonly used for stimulating growth or preventing post-weaning enteritis in pigs converge in promoting microbial production of bile acids (BA) in the intestine. This leads to tissue-specific modifications in the proportion of BA, thereby amplifying BA signaling in intestine, liver, and white adipose tissue (WAT). Activation of BA-regulated pathways ultimately reinforces the intestinal protection against bacterial infection and pathological secretion of fluids and electrolytes, attenuates inflammation in colon and WAT, alters protein and lipid metabolism in liver, and increases the circulating levels of the hormone FGF19. Conceivably, these alterations could spare nutrients for growth and improve the metabolic efficiency of AMA-treated animals. This work provides evidence that BA act as signaling molecules that mediate host physiological, metabolic, and immune responses to the AMA-induced alterations in gut microbial metabolism, eventually permitting the growth-promoting action of AMA. Consequently, BA emerge as a promising target for developing efficacious alternatives to AMA

Influence of supplementation with two specific inactivated dry yeast and grape-skin extract on the color and composition of red wine

Wines from grapes of Cabernet Sauvignon of the AOC Tarragona were elaborated with supplementation or not of two specific inactivated dry yeasts (Optired® and Optimum Red®; Lallemand Inc.) or with an experimental grape-skin extract. All the wines treated were significantly less astringent than the control wine because both inactivated dry yeast and the skin extract released polysaccharides which probably inhibit interactions between salivary proteins and tannins, and because their presence decrease the proportion of seed tannins and increase the proportion of skin tannins in the final wines

New insight about the functionality of oenological tannins; Main results of the working group on oenological tannins

This communication synthetize all the results obtained by the OIV working group on oenological tannins to the current date. The obtained results confirm that oenological tannins really exert a protection effect against grape juice and wine oxidation because they have antioxidant activity, they consume directly oxygen and they exert an inhibitory effect on the laccase activity. Moreover, oenological tannins also exert a copigmentation effect which can improve and protect de color of red wines

Meteorin-like/ Meteorin-b protects heart against cardiac dysfunction

Meteorin-like/Meteorin-β (Metrnl/Metrnβ) is a secreted protein produced by skeletal muscle and adipose tissue that exerts metabolic actions that improve glucose metabolism. The role of Metrnβ in cardiac disease is completely unknown. Here, we show that Metrnβ-null mice exhibit asymmetrical cardiac hypertrophy, fibrosis, and enhanced signs of cardiac dysfunction in response to isoproterenol-induced cardiac hypertrophy and aging. Conversely, adeno-associated virus-mediated specific overexpression of Metrnβ in the heart prevents the development of cardiac remodeling. Furthermore, Metrnβ inhibits cardiac hypertrophy development in cardiomyocytes in vitro, indicating a direct effect on cardiac cells. Antibody-mediated blockage of Metrnβ in cardiomyocyte cell cultures indicated an autocrine action of Metrnβ on the heart, in addition to an endocrine action. Moreover, Metrnβ is highly produced in the heart, and analysis of circulating Metrnβ concentrations in a large cohort of patients reveals that it is a new biomarker of heart failure with an independent prognostic value

Adipose tissue knockdown of lysozyme reduces local inflammation and improves adipogenesis in high-fat diet-fed mice

Chronic systemic low-level inflammation in metabolic disease is known to affect adipose tissue biology. Lysozyme (LYZ) is a major innate immune protein but its role in adipose tissue has not been investigated. Here, we aimed to investigate LYZ in human and rodents fat depots, and its possible role in obesity-associated adipose tissue dysfunction. LYZ mRNA and protein were identified to be highly expressed in adipose tissue from subjects with obesity and linked to systemic chronic-low grade inflammation, adipose tissue inflammation and metabolic disturbances, including hyperglycemia, dyslipidemia and decreased markers of adipose tissue adipogenesis. These findings were confirmed in experimental models after a high-fat diet in mice and rats and also in ob/ob mice. Importantly, specific inguinal and perigonadal white adipose tissue lysozyme (Lyz2) gene knockdown in high-fat diet-fed mice resulted in improved adipose tissue inflammation in parallel to reduced lysozyme activity. Of note, Lyz2 gene knockdown restored adipogenesis and reduced weight gain in this model. In conclusion, altogether these observations point to lysozyme as a new actor in obesity-associated adipose tissue dysfunction. The therapeutic targeting of lysozyme production might contribute to improve adipose tissue metabolic homeostasis

SIRT3-mediated inhibition of FOS through histone H3 deacetylation prevents cardiac fibrosis and inflammation.

Sirtuin 3 (SIRT3) is a deacetylase that modulates proteins that control metabolism and protects against oxidative stress. Modulation of SIRT3 activity has been proposed as a promising therapeutic target for ameliorating metabolic diseases and associated cardiac disturbances. In this study, we investigated the role of SIRT3 in inflammation and fibrosis in the heart using male mice with constitutive and systemic deletion of SIRT3 and human cardiac AC16 cells. SIRT3 knockout mice showed cardiac fibrosis and inflammation that was characterized by augmented transcriptional activity of AP-1. Consistent with this, SIRT3 overexpression in human and neonatal rat cardiomyocytes partially prevented the inflammatory and profibrotic response induced by TNF-alpha. Notably, these effects were associated with a decrease in the mRNA and protein levels of FOS and the DNA-binding activity of AP-1. Finally, we demonstrated that SIRT3 inhibits FOS transcription through specific histone H3 lysine K27 deacetylation at its promoter. These findings highlight an important function of SIRT3 in mediating the often intricate profibrotic and proinflammatory responses of cardiac cells through the modulation of the FOS/AP-1 pathway. Since fibrosis and inflammation are crucial in the progression of cardiac hypertrophy, heart failure, and diabetic cardiomyopathy, our results point to SIRT3 as a potential target for treating these diseases

The value of selected in vitro and in silico methods to predict acute oral toxicity in a regulatory context: results from the European Project ACuteTox

ACuteTox is a project within the 6th European Framework Programme which had as one of its goals to develop, optimise and prevalidate a non-animal testing strategy for predicting human acute oral toxicity. In its last 6months, a challenging exercise was conducted to assess the predictive capacity of the developed testing strategies and final identification of the most promising ones. Thirty-two chemicals were tested blind in the battery of in vitro and in silico methods selected during the first phase of the project. This paper describes the classification approaches studied: single step procedures and two step tiered testing strategies. In summary, four in vitro testing strategies were proposed as best performing in terms of predictive capacity with respect to the European acute oral toxicity classification. In addition, a heuristic testing strategy is suggested that combines the prediction results gained from the neutral red uptake assay performed in 3T3 cells, with information on neurotoxicity alerts identified by the primary rat brain aggregates test method. Octanol-water partition coefficients and in silico prediction of intestinal absorption and blood-brain barrier passage are also considered. This approach allows to reduce the number of chemicals wrongly predicted as not classified (LD(50)>2000mg/kg b.w.).Peer Reviewe

Towards an alternative testing strategy for nanomaterials used in nanomedicine: lessons from NanoTEST.

In spite of recent advances in describing the health outcomes of exposure to nanoparticles (NPs), it still remains unclear how exactly NPs interact with their cellular targets. Size, surface, mass, geometry, and composition may all play a beneficial role as well as causing toxicity. Concerns of scientists, politicians and the public about potential health hazards associated with NPs need to be answered. With the variety of exposure routes available, there is potential for NPs to reach every organ in the body but we know little about the impact this might have. The main objective of the FP7 NanoTEST project ( www.nanotest-fp7.eu ) was a better understanding of mechanisms of interactions of NPs employed in nanomedicine with cells, tissues and organs and to address critical issues relating to toxicity testing especially with respect to alternatives to tests on animals. Here we describe an approach towards alternative testing strategies for hazard and risk assessment of nanomaterials, highlighting the adaptation of standard methods demanded by the special physicochemical features of nanomaterials and bioavailability studies. The work has assessed a broad range of toxicity tests, cell models and NP types and concentrations taking into account the inherent impact of NP properties and the effects of changes in experimental conditions using well-characterized NPs. The results of the studies have been used to generate recommendations for a suitable and robust testing strategy which can be applied to new medical NPs as they are developed

Report from the EPAA workshop: In vitro ADME in safety testing used by EPAA industry sectors

AbstractThere are now numerous in vitro and in silico ADME alternatives to in vivo assays but how do different industries incorporate them into their decision tree approaches for risk assessment, bearing in mind that the chemicals tested are intended for widely varying purposes? The extent of the use of animal tests is mainly driven by regulations or by the lack of a suitable in vitro model. Therefore, what considerations are needed for alternative models and how can they be improved so that they can be used as part of the risk assessment process? To address these issues, the European Partnership for Alternative Approaches to Animal Testing (EPAA) working group on prioritisation, promotion and implementation of the 3Rs research held a workshop in November, 2008 in Duesseldorf, Germany. Participants included different industry sectors such as pharmaceuticals, cosmetics, industrial- and agro-chemicals. This report describes the outcome of the discussions and recommendations (a) to reduce the number of animals used for determining the ADME properties of chemicals and (b) for considerations and actions regarding in vitro and in silico assays. These included: standardisation and promotion of in vitro assays so that they may become accepted by regulators; increased availability of industry in vivo kinetic data for a central database to increase the power of in silico predictions; expansion of the applicability domains of in vitro and in silico tools (which are not necessarily more applicable or even exclusive to one particular sector) and continued collaborations between regulators, academia and industry. A recommended immediate course of action was to establish an expert panel of users, developers and regulators to define the testing scope of models for different chemical classes. It was agreed by all participants that improvement and harmonization of alternative approaches is needed for all sectors and this will most effectively be achieved by stakeholders from different sectors sharing data

Developmental and tissue-specific involvement of peroxisome proliferator-activated receptor-alpha in the control of mouse uncoupling protein-3 gene expression.

Uncoupling protein-3 (UCP3) is a member of the mitochondrial carrier family expressed preferentially in skeletal muscle and heart. It appears to be involved in metabolic handling of fatty acids in a way that minimizes excessive production of reactive oxygen species. Fatty acids are powerful regulators of UCP3 gene transcription. We have found that the role of peroxisome proliferator-activated receptor-α (PPARα) on the control of UCP3 gene expression depends on the tissue and developmental stage. In adults, UCP3 mRNA expression is unaltered in skeletal muscle from PPARα-null mice both in basal conditions and under the stimulus of starvation. In contrast, UCP3 mRNA is down-regulated in adult heart both in fed and fasted PPARα-null mice. This occurs despite the increased levels of free fatty acids caused by fasting in PPARα-null mice. In neonates, PPARα-null mice show impaired UCP3 mRNA expression in skeletal muscle in response to milk intake, and this is not a result of reduced free fatty acid levels. The murine UCP3 promoter is activated by fatty acids through either PPARα or PPARδ but not by PPARγ or retinoid X receptor alone. PPARδ-dependent activation could be a potential compensatory mechanism to ensure appropriate expression of UCP3 gene in adult skeletal muscle in the absence of PPARα. However, among transcripts from other PPARα and PPARδ target genes, only those acutely induced by milk intake in wild-type neonates were altered in muscle or heart from PPARα-null neonates. Thus, PPARα-dependent regulation is required for appropriate gene regulation of UCP3 as part of the subset of fatty-acid-responsive genes in neonatal muscle and heart