Review Inflammation and oxidative stress in

BioGéoSciences, CNRS UMR 5561, Université de Bourgogne, 6 Boulevard Gabriel, 21000 Dijon, France.
Philosophical Transactions of The Royal Society B Biological Sciences (Impact Factor: 7.06). 11/2008; 364(1513):71-83. DOI: 10.1098/rstb.2008.0151
Source: PubMed


Innate, inflammation-based immunity is the first line of vertebrate defence against micro-organisms. Inflammation relies on a number of cellular and molecular effectors that can strike invading pathogens very shortly after the encounter between inflammatory cells and the intruder, but in a non-specific way. Owing to this non-specific response, inflammation can generate substantial costs for the host if the inflammatory response, and the associated oxygen-based damage, get out of control. This imposes strong selection pressure that acts to optimize two key features of the inflammatory response: the timing of activation and resolution (the process of downregulation of the response). In this paper, we review the benefits and costs of inflammation-driven immunity. Our aim is to emphasize the importance of resolution of inflammation as a way of maintaining homeostasis against oxidative stress and to prevent the 'horror autotoxicus' of chronic inflammation. Nevertheless, host immune regulation also opens the way to pathogens to subvert host defences. Therefore, quantifying inflammatory costs requires assessing (i) short-term negative effects, (ii) delayed inflammation-driven diseases, and (iii) parasitic strategies to subvert inflammation.

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    • "In addition to being demanding in terms of energy and antioxidant resources to overcome oxidative stress, reproduction is also associated with increased susceptibility to infection by parasites (Sheldon & Verhulst 1996; Mennerat et al. 2009b; Christe et al. 2012; Van de Crommenacker et al. 2012). This is because, in addition to direct competition between immunity and reproduction for energy (Sheldon & Verhulst 1996), infections by pathogens trigger an inflammatory response, which leads to the production of large amounts of free radicals that may generate oxidative stress (Bedard & Krause 2007; Sorci & Faivre 2009). Hence, since reproductive investment is traded off against immune response and down-regulation of oxidative stress (Sheldon & Verhulst 1996; Harshman & Zera 2007), the effects of pathogenic micro-organisms on hosts are expected to increase with reproductive investment (Mennerat et al. 2009b; Christe et al. 2012; Van de Crommenacker et al. 2012). "
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    ABSTRACT: Parasites influence allocation trade-offs between reproduction and self-maintenance and consequently shape host life-history traits. The host microbiome includes pathogenic and commensal micro-organisms that are remarkable in their diversity and ubiquity. However, experimental studies investigating whether the microbiome shapes host reproduction are still lacking.In this study, we tested whether the microbiome affects three important components of bird reproduction, namely (i) the maternal transfer of anti-microbial compounds to the eggs, (ii) the development of nestlings and (iii) the trade-off between reproduction and self-maintenance, here measured by the oxidative costs of reproduction.We experimentally modified the microbiome of wild breeding Great tits (Parus major) by spraying nests with liquid solution that either favoured or inhibited bacterial growth compared to a control. These treatments modified the bacterial communities in the nests and on adult feathers.We found that females from the treatment that decreased bacterial densities in the nests laid eggs with less carotenoids than females from the control, while we found no significant effect of increasing bacterial densities and modifying community composition compared to the control. Nestlings exposed to decreased bacterial densities grew faster and had longer tarsus length at fledging. Moreover, our analyses revealed that the relationship between investment in reproduction and oxidative damage was affected by the treatments. Adults raising larger clutches suffered higher oxidative damage in control nests, whereas this oxidative cost of reproduction was not detected when we modified bird microbiome.Our study provides experimental evidence for an effect of the microbiome on egg carotenoid investment, nestling development and oxidative cost of reproduction and thus highlights the major effect that the microbiome may have on the evolution of host life-history strategies.
    Full-text · Article · Aug 2015 · Functional Ecology
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    • "The black circles and the solid linear regression line represent exposed fish sired by exposed fathers and the white circles and the dashed linear regression line represent exposed fish sired by unexposed fathers. tive oxygen and nitrogen radicals which can damage proteins, lipids, DNA and can disrupt mitochondrial function (Sorci & Faivre 2009). "
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    ABSTRACT: Forces shaping an individual's phenotype are complex and include transgenerational effects. Despite low investment into reproduction, a father's environment and phenotype can shape its offspring's phenotype. Whether and when such paternal effects are adaptive, however, remains elusive. Using three-spined sticklebacks in controlled infection experiments, we show that sperm deficiencies in exposed males compared to their unexposed brothers functionally translated into reduced reproductive success in sperm competition trials. In non-competitive fertilisations, off-spring of exposed males suffered significant costs of reduced hatching success and survival but they reached a higher body condition than their counterparts from unexposed fathers after experi-mental infection. Interestingly, those benefits of paternal infection did not result from increased resistance but from increased tolerance to the parasite. Altogether, these results demonstrate that parasite resistance and tolerance are shaped by processes involving both genetic and non-genetic inheritance and suggest a context-dependent adaptive value of paternal effects. Keywords Host–parasite interaction, in vitro fertilisation, paternal effects, sperm phenotype, three-spined stickleback. Ecology Letters (2014) INTRODUCTION
    Full-text · Article · Nov 2014 · Ecology Letters
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    • "We measured six immunological variables to characterize the immune system and to study its response to infection over the annual cycle (leukocyte counts: heterophils, lymphocytes, and total leukocytes; activity of natural antibodies and the complement system: hemolysis and hemagglutination; lysozyme level). We also measured two components of the antioxidant system (total antioxidant status [TAS] and the concentration of uric acid [UA]) and evaluated oxidative damage on the membrane lipids (concentration of malondialdehyde [MDA]) because immune system activation can affect the antioxidant system (Costantini and Møller 2009; Monaghan et al. 2009; Sorci and Faivre 2009). All these variables of immune function and oxidative status (except lysozyme) have been shown to be affected by coccidian infection in wild birds (Hõrak et al. 2004; Pap et al. 2009, 2011; Sepp et al. 2012a; Bó kony et al. 2014). "
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    ABSTRACT: Temporally changing environmental conditions occur in most parts of the world and can exert strong pressure on the immune defense of organisms. Seasonality may result in changes in physiological traits over the year, and such changes may be essential for the optimization of defense against infections. Evidence from field and laboratory studies suggest the existence of links between environmental conditions, such as infection risk, and the ability of animals to mount an immune response or to overcome infections; however, the importance of parasites in mediating seasonal change in immune defense is still debated. In this study, we test the hypothesis that seasonal change in immune function and connected physiological traits is related to parasite infection. We sampled captive house sparrows (Passer domesticus) once every 2 mo over 14 mo and compared the annual variation in 12 measures of condition, immune function, antioxidant status, and oxidative damage among birds naturally infested with coccidians or medicated against these parasites. We found significant variation in 10 of 12 traits over the year. However, we found little support for parasite-mediated change in immune function and oxidative status in captive house sparrows. Of the 12 measures, only one was slightly affected by parasite treatment. In support of the absence of any effect of coccidians on the annual profile of the condition and physiological traits, we found no consistent relationships between the intensity of infestation and these response variables over the year. Our results show that chronic coccidian infections have limited effect on the seasonal changing of physiological traits and that the patterns of these measures are probably more affected by acute infection and/or virulent parasite strains.
    Full-text · Article · Sep 2014 · Physiological and Biochemical Zoology
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