Tumour necrosis factor receptor deficiency alters anxiety-like behavioural and neuroendocrine stress responses of mice

Tumour necrosis factor (TNF)-alpha is known to be involved in anxiety and the regulation of the hypothalamic-pituitary-adrenal axis. To examine the role of its receptors in neuroendocrine immunomodulation, we studied behaviour, corticosterone production and T-cell activation in mice with a C57BL/6J background and deficient for one or both TNF receptors (TNFR1-/-, TNFR2-/-, and TNFR1+2-/-) compared to wildtype C57BL/6J mice with and without psychological stress. Stress was induced by social disruption (SDR), and anxiety-like behaviour was examined using the elevated plus maze (EPM). Anxiety of unstressed TNFR1+2-/- mice was increased compared to C57BL/6J mice as shown by reduced ratios of entries into open arms relatively to total entries. SDR-stressed TNFR1+2-/- mice showed reduced ratios of entries into open arms relatively to total entries, reduced ratios of distances walked in open relatively to distances walked in both arms and reduced time in open arms compared to C57BL/6J mice. Locomotor activity of unstressed and SDR-stressed TNFR1-/- and TNFR2-/- mice was reduced. Serum corticosterone concentrations of control mice do not differ between mouse strains. However, TNFR1+2-/- mice had significantly higher corticosterone concentrations than C57BL/6J mice after SDR. EPM testing significantly increased corticosterone concentrations in all strains. Mitogen-induced activation-marker expression was reduced in TNFR1-/- T-helper cells under control and stress conditions, while activation marker expression of TNFR2-/- and TNFR1+2-/- cells was only slightly affected by stress compared to C57BL/6J T cells. Our study suggests that both TNF receptors contribute to anxiety-like behaviour and corticosterone responses, whereas TNFR1 has a larger impact on T-cell activation.     

The age of hair matters – the incorporation of cortisol by external contamination is enhanced in distal hair segments of pigs and cattle

Hair cortisol concentration (HCC) is used as an indicator of long-term stress or pathologies in humans and increasingly in animals. Although the main mechanism for the incorporation of cortisol into the hair shaft is by diffusion from blood, cortisol may also be incorporated from external sources by contamination of the hair surface. In farm animals under conventional husbandry conditions and trapped animals, contamination of hair with cortisol-containing body fluids, especially with urine, was shown to be a considerable confounding factor when studying HCCs. We recently found that cattle and pigs exhibit elevated HCCs in distal hair segments and assume that the incorporation of external cortisol is facilitated in these older hair segments. Therefore, the aim of this study was to investigate the effects of urine contamination on HCC in different hair segments of pigs and cattle, and to determine whether different cleaning protocols can prevent contamination effects. In an in vivo experiment in pigs (n = 18) and an in vitro experiment in cattle (n = 12), hairs were repeatedly contaminated with urine of the respective species and then shaved or cut in segments. Cortisol concentrations in hair segments were analysed by enzyme immunoassay after washing with isopropanol and extraction with methanol. Results were compared with HCCs in untreated hairs or hairs treated with water. Moreover, additional bovine hair samples contaminated with urine were subjected to two further cleaning procedures. Contamination with urine generally increased HCCs, and it was demonstrated for the first time that this effect is more pronounced in distal compared to proximal hair segments in both species. The immersion of bovine hair in vitro in water caused a washout of cortisol, which was also more pronounced in distal hair segments. In general, the different cleaning protocols for cattle hair did not prevent contamination effects, so we assume that external cortisol not only adheres but is incorporated into the hair shaft. Structural damage of older, distal hair segments may facilitate permeability of the hair matrix and diffusion of cortisol from and into aqueous solutions. Thus, the validity of HCC as a marker of stress is compromised in animals where soiling of hair with body fluids is a risk factor. Therefore, hair samples should be collected from clean body regions and, if possible, using proximal hair segments.     

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Morphology of porcine cumulus-oocyte-complexes depends on the stage of preovulatory maturation

The aim of this investigation was to determine the relationship between the morphology of the cumulus-oocyte-complexes (COCs) and the meiotic configuration of oocytes as an LH peak mimicked by hCG. Estrus was synchronized in a total of 29 crossbred Landrace gilts by feeding Regumate for 15 d and administering 1000 IU PMSG. The LH peak was simulated by treatment with 500 IU hCG at 80 h after PMSG. Endoscopic oocyte recovery was carried out 2 h before and 10, 22 and 34 h after hCG. Only macroscopically healthy follicles with a diameter of more than 5 mm were punctured. Altogether, 410 follicles from 57 ovaries were punctured and 251 COCs were aspirated. Oocyte recovery rate increased from 48.5% (P < 0.01) of the early, not yet preovulatory follicles (2 h before hCG) to 80.8% of late preovulatory follicles (34 h after hCG). Cumulus morphology in COCs recovered 2 h before and 10 h after hCG was heterogeneous, with most (72.9 to 57.4%; P < 0.01) showing a compact or slightly expanded cumulus. Starting at about 22 h after hCG, COC morphology changed dramatically (86.7% of COCs with expanded cumulus; P < 0.01), and 34 h after hCG, 98.3% of the COCs had only an expanded cumulus. The percentage of oocytes with a mature meiotic configuration increased (11.2; 7.1; 41.4 and 70.2%, respectively, n = 238 oocytes; P < 0.01) as the interval post hCG increased (-2, 10, 22, 34 h, respectively). Meiotic configuration was related to COC morphology: compact COCs--88.9% diplotene, expanded COCs--53.8% metaphase II (M-II), and denuded oocytes--69.2% degenerated chromatin. These results indicate that there is a relationship between oocyte recovery rate, COC morphology, and meiotic configuration and preovulatory follicle maturation after the application of hCG.     

Initial results and long-term clinical follow-up of an amorphous hydrogenated silicon-carbide-coated stent in daily practice

The hemocompatibility and biocompatibility of a stent are determined by the physical and electrochemical properties of the stent surface. The aim of this study was to determine the feasibility, safety and efficacy of implantation of a stent coated with silicon carbide. Baseline characteristics were collected prospectively. The occurrence of cardiac adverse events and the angina score were assessed at clinical follow-up. A total of 193 Tensum stents were implanted in 174 patients. In hospital, one patient experienced stent thrombosis and in 6% of the patients a creatinine kinase elevation to 240 U/l or more occurred. Long-term follow-up was performed in 172 patients, with a mean follow-up of 454 +/- 181 days. Ninety-seven per cent were still alive, 15% had undergone target-vessel revascularization, and 2% had angiographic restenosis and were treated with medication only. Seventy-one per cent of the patients were free of anginal complaints, and 20% had anginal complaints in Canadian Cardiac Society class I or II. The Tensum coronary stent showed to be a safe and efficacious device in this study, with a high primary success rate and favorable long-term clinical followup.     

Social support attenuates the adverse consequences of social deprivation stress in domestic piglets

Social deprivation is a severe stressor affecting a number of behavioral and physiological functions of gregarious species. It is assumed that, dependent upon the level of familiarity, social support given by a conspecific may attenuate the adverse consequences of stress. We investigated the effects of a 4 h maternal and littermate deprivation on behavioral reactions, stress hormone responses and brain corticosteroid receptor expression in 7-, 21- and 35-day-old domestic piglets (Sus scrofa) that were left alone or in the presence either of a familiar or unfamiliar age-matched piglet. Compared to control animals, all of the socially deprived piglets showed significant stress responses, such as impaired habituation in repeated open-field/novel-object tests, enhanced ACTH and cortisol release, and altered corticosteroid receptor expression in the hypothalamus. In addition, our results demonstrated that younger piglets had more difficulty coping with stress. The presence of an age-matched conspecific had a direct calming effect on the deprived piglet during the deprivation procedure, which was revealed by diminished stress-induced HPA activity and altered reactions in the behavioral test situations (e.g., activity, escape, and vocalization). Furthermore, because the presence of a familiar piglet causes a more pronounced buffering effect, we have shown for the first time that the degree of familiarity between the piglets may influence the effectiveness of social support. Our study emphasizes the benefits of social partners on positive welfare and the ability for pigs to cope with stress; therefore, our results should be taken into account during handling practices such as weaning and mixing.     

The molecular archaeology of a mitochondrial death effector: AIF in Drosophila

Apoptosis-inducing factor (AIF) is a phylogenetically conserved redox-active flavoprotein that contributes to cell death and oxidative phosphorylation in Saccharomyces cerevisiae, Caenorhabditis elegans, mouse and humans. AIF has been characterized as a caspase-independent death effector that is activated by its translocation from mitochondria to the cytosol and nucleus. Here, we report the molecular characterization of AIF in Drosophila melanogaster, a species in which most cell deaths occur in a caspase-dependent manner. Interestingly, knockout of zygotic D. melanogaster AIF (DmAIF) expression using gene targeting resulted in decreased embryonic cell death and the persistence of differentiated neuronal cells at late embryonic stages. Although knockout embryos hatch, they undergo growth arrest at early larval stages, accompanied by mitochondrial respiratory dysfunction. Transgenic expression of DmAIF misdirected to the extramitochondrial compartment (DeltaN-DmAIF), but not wild-type DmAIF, triggered ectopic caspase activation and cell death. DeltaN-DmAIF-induced death was not blocked by removal of caspase activator Dark or transgenic expression of baculoviral caspase inhibitor p35, but was partially inhibited by Diap1 overexpression. Knockdown studies revealed that DeltaN-DmAIF interacts genetically with the redox protein thioredoxin-2. In conclusion, we show that Drosophila AIF is a mitochondrial effector of cell death that plays roles in developmentally regulated cell death and normal mitochondrial function.