Macrophages influence Schwann cell myelin autophagy after nerve injury and in a model of Charcot-Marie-Tooth disease.

BACKGROUND AND AIMS: The complex cellular and molecular interactions between Schwann cells (SCs) and macrophages during Wallerian degeneration are a prerequisite to allow rapid uptake and degradation of myelin debris and axonal regeneration after peripheral nerve injury. In contrast, in non-injured nerves of Charcot-Marie-Tooth 1 neuropathies, aberrant macrophage activation by SCs carrying myelin gene defects is a disease amplifier that drives nerve damage and subsequent functional decline. Consequently, targeting nerve macrophages might be a translatable treatment strategy to mitigate disease outcome in CMT1 patients. Indeed, in previous approaches, macrophage targeting alleviated the axonopathy and promoted sprouting of damaged fibers. Surprisingly, this was still accompanied by robust myelinopathy in a model for CMT1X, suggesting additional cellular mechanisms of myelin degradation in mutant peripheral nerves. We here investigated the possibility of an increased SC-related myelin autophagy upon macrophage targeting in Cx32def mice. METHODS: Combining ex vivo and in vivo approaches, macrophages were targeted by PLX5622 treatment. SC autophagy was investigated by immunohistochemical and electron microscopical techniques. RESULTS: We demonstrate a robust upregulation of markers for SC autophagy after injury and in genetically-mediated neuropathy when nerve macrophages are pharmacologically depleted. Corroborating these findings, we provide ultrastructural evidence for increased SC myelin autophagy upon treatment in vivo. INTERPRETATION: These findings reveal a novel communication and interaction between SCs and macrophages. This identification of alternative pathways of myelin degradation may have important implications for a better understanding of therapeutic mechanisms of pharmacological macrophage targeting in diseased peripheral nerves.

Aß1-16 controls synaptic vesicle pools at excitatory synapses via cholinergic modulation of synapsin phosphorylation.

Amyloid beta (Aß) is linked to the pathology of Alzheimer's disease (AD). At physiological concentrations, Aß was proposed to enhance neuroplasticity and memory formation by increasing the neurotransmitter release from presynapse. However, the exact mechanisms underlying this presynaptic effect as well as specific contribution of endogenously occurring Aß isoforms remain unclear. Here, we demonstrate that Aß1-42 and Aß1-16, but not Aß17-42, increased size of the recycling pool of synaptic vesicles (SV). This presynaptic effect was driven by enhancement of endogenous cholinergic signalling via α7 nicotinic acetylcholine receptors, which led to activation of calcineurin, dephosphorylation of synapsin 1 and consequently resulted in reorganization of functional pools of SV increasing their availability for sustained neurotransmission. Our results identify synapsin 1 as a molecular target of Aß and reveal an effect of physiological concentrations of Aß on cholinergic modulation of glutamatergic neurotransmission. These findings provide new mechanistic insights in cholinergic dysfunction observed in AD.

RNA processing bodies are disassembled during Old World alphavirus infection.

RNA processing bodies (P-bodies) are non-membranous cytoplasmic aggregates of mRNA and proteins involved in mRNA decay and translation repression. P-bodies actively respond to environmental stresses, associated with another type of RNA granules, known as stress granules (SGs). Alphaviruses were previously shown to block SG induction at late stages of infection, which is important for efficient viral growth. In this study, we found that P-bodies were disassembled or reduced in number very early in infection with Semliki Forest virus (SFV) or chikungunya virus (CHIKV) in a panel of cell lines. Similar to SGs, reinduction of P-bodies by a second stress (sodium arsenite) was also blocked in infected cells. The disassembly of P-bodies still occurred in non-phosphorylatable eIF2α mouse embryonal fibroblasts (MEFs) that are impaired in SG assembly. Studies of translation status by ribopuromycylation showed that P-body disassembly is independent of host translation shutoff, which requires the phosphorylation of eIF2α in the SFV- or CHIKV-infected cells. Labelling of newly synthesized RNA with bromo-UTP showed that host transcription shutoff correlated with P-body disassembly at the same early stage (3-4 h) after infection. However, inhibition of global transcription with actinomycin D (ActD) failed to disassemble P-bodies as effectively as the viruses did. Interestingly, blocking nuclear import with importazole led to an efficient P-bodies loss. Our data reveal that P-bodies are disassembled independently from SG formation at early stages of Old World alphavirus infection and that nuclear import is involved in the dynamic of P-bodies.

New insights into neonatal coagulation: normal clot formation despite lower intra-clot thrombin levels.

BACKGROUND: Healthy neonates exhibit no bleeding tendencies, but exhibit longer partial thromboplastin times than adults. Lower clotting factor levels may be balanced by lower inhibitor levels, which is not reflected in routine coagulation assays, but could result in normal clot formation in vivo. The novel thrombodynamics assay simulates a damaged vessel with tissue factor immobilized to a surface. We hypothesized that intra-clot thrombin levels and spatial fibrin clot formation with this assay are comparable in neonates and adults. METHODS: Coagulation was tested in plasma from venous neonatal blood (N = 12), cord blood (N = 30), and adult blood (N = 20) using thrombodynamics and calibrated automated thrombography. RESULTS: Neonates exhibited a higher initial rate of clot formation than adults (adult: 60.7 ± 3.9 µm/min; neonatal: 66.8 ± 3.9 µm/min; cord: 68.1 ± 3.3 µm/min; P < 0.001) and a comparable stationary rate of clot formation (adult: 35.8 ± 8.5 µm/min; neonatal: 37.0 ± 4.6 µm/min; cord: 36.0 ± 5.2 µm/min; P = 0.834). Intra-clot thrombin levels were lower in neonates (adult: 41.9 ± 11.2 AU/l; neonatal: 22.6 ± 10.2 AU/l; cord: 23.6 ± 9.7 AU/l; P < 0.001), but the longitudinal rate of thrombin propagation was comparable (adult: 27.2 ± 4.2 µm/min neonatal; 27.9 ± 2.9 µm/min; cord: 27.6 ± 3.4 µm/min; P = 0.862). CONCLUSIONS: Despite lower intra-clot thrombin levels, neonates exhibit normal spatial fibrin clot growth, which concurs with clinically well-functioning hemostasis in healthy neonates.

The conundrum of postpartum thrombotic Microangiopathy: case report and considerations for management.

BACKGROUND: Microangiopathic hemolytic anemias and thrombocytopenias in pregnant or postpartum women constitute an interdisciplinary diagnostic and therapeutic challenge in the evaluation of thrombotic microangiopathies (TMA), where urgent care must be considered. CASE PRESENTATION: We here report the case of a 21-year-old Somali woman, who was delivered by emergency caesarean section at 35 weeks of gestational age with acute dyspnea, placental abruption and gross edema due to severe preeclampsia/HELLP syndrome. After delivery, she developed acute kidney failure and thrombotic microangiopathy as revealed by kidney biopsy. The lack of early response to plasma exchange prompted extensive laboratory workup. Ultimately, the patient completely recovered with negative fluid balance and control of severe hypertension. CONCLUSIONS: This case report emphasizes the importance to differentiate between primary TMA syndromes and microangiopathic hemolytic anemias due to systemic disorders. Delayed recovery from preeclampsia/HELLP syndrome and malignant hypertension can clinically mimic primary TMA syndromes in the postpartum period.

Phytate degradation, intestinal microbiota, microbial metabolites and immune values are changed in growing pigs fed diets with varying calcium-phosphorus concentration and fermentable substrates.

The present study assessed effects of diets containing varying calcium-phosphorus (CaP) concentration and fermentable substrates on digestibility of diets, intestinal microbiota and immune system using 32 crossbred pigs (initial BW 54.7 kg). In a 2 × 2 factorial arrangement, pigs were fed either a corn-soybean meal (CSB) or corn-field pea (CFP) diet with either low [-] (4.4 g Ca/kg; 4.2 g total P/kg) or high [+] (8.3 g Ca/kg; 7.5 g total P/kg; supplemented with monocalcium phosphate) CaP content for a period of 9 weeks. In week 8, blood samples were taken, and at the end of the trial, all pigs were euthanized to collect digesta and mesenteric lymphoid tissue. Apparent total tract digestibility (ATTD) of P was greater (p < 0.05) for pigs fed the CaP+ and CFP diets than CaP- and CSB diets. The myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6 ) concentration in jejunal digesta was higher (p < 0.05) for CaP+ than in CaP- fed pigs. In addition, caecal and faecal InsP5 isomer concentration were greater (p < 0.05) for CSB than CFP diets. In the caecum, gene copy numbers of saccharolytic bacteria, such as Eubacterium rectale and Roseburia spp., as well as SCFA concentration were higher (p < 0.05) for CaP+ than CaP- diets. In particular, innate immune cell numbers, such as natural killer cells, dendritic cells, monocytes and neutrophils, were greater (p < 0.05) for CaP+ than CaP- fed pigs. Diets high in CaP resulted in higher abundance of potential beneficial bacteria and might promote the first line of defence enhancing the activation of the cellular adaptive immune response, thereby possibly decreasing the risk for intestinal disturbances. These results strongly suggest that both, CaP supply and dietary ingredients differing in fermentability, may beneficially affect gut health through increase in SCFA-producing bacteria and/or bacteria with anti-inflammatory properties.

Activated protein C resistance assay and factor V Leiden.

The authors suggest that functional testing for activated protein C resistance is cheaper and more clinically relevant than genetic testing to detect a factor V Leiden mutation in identifying persons who are at risk for thromboembolism.

Short- and long-term perinatal outcome in twin pregnancies affected by weight discordance.

INTRODUCTION: The objective was to investigate the association between chorionicity-specific intertwin birthweight discordance and adverse outcomes including long-term follow up at 6, 18, and 48-60 months after term via Ages and Stages Questionnaire. MATERIAL AND METHODS: In this secondary analysis of a cohort study (Oldenburg et al., n = 1688) and a randomized controlled trial (PREDICT study, n = 1045) twin pairs were divided into three groups according to chorionicity-specific birthweight discordance: <75th percentile, 75th-90th percentile and >90th percentile. Information on infant mortality, admittance to neonatal intensive care units, and gestational age at delivery was available for all pairs. Detailed neonatal outcomes were available for 656 pairs from PREDICT, of which 567 pairs had at least one Ages and Stages Questionnair follow-up. Logistic regression models were used for dichotomous outcomes. Ages and Stages Questionnair scores were compared using the method of generalized estimating equation to account for the correlation within twins. RESULTS: The 75th and 90th percentiles for birthweight discordance were 14.8 and 21.4% for monochorionic and 16.0 and 23.8% for dichorionic twins. After adjustment for small for gestational age and gender, birthweight discordance >75th and >90th percentile was associated with induced delivery <34 weeks [odds ratio 1.71 (95% confidence interval 1.11-2.65) and odds ratio 2.83 (95% confidence interval 1.73-4.64), respectively]. Discordance >75th-percentile was associated with an increased risk of infant mortality after 28 days [odds ratio 4.69 (95% confidence interval 1.07-20.45)] but not with major neonatal complications or with low mean Ages and Stages Questionnair scores at 6, 18, and 48-60 months after term. CONCLUSION: Chorionicity-specific intertwin birthweight discordance is a risk factor for induced preterm delivery and infant mortality, but not for lower scores for neurophysiological development at 6, 18, and 48-60 months.

Insulin resistance alters hepatic ethanol metabolism: studies in mice and children with non-alcoholic fatty liver disease.

OBJECTIVE: Increased fasting blood ethanol levels, suggested to stem from an increased endogenous ethanol synthesis in the GI tract, are discussed to be critical in the development of non-alcoholic fatty liver disease (NAFLD). The aim of the present study was to further delineate the mechanisms involved in the elevated blood ethanol levels found in patients with NAFLD. DESIGN: In 20 nutritionally and metabolically screened children displaying early signs of NAFLD and 29 controls (aged 5-8 years), ethanol plasma levels were assessed. Ethanol levels along the GI tract, in vena cava and portal vein, intestinal and faecal microbiota, and activity of alcohol dehydrogenase (ADH) and cytochrome P450 2E1 (CYP2E1) were measured in wild-type, ob/ob and anti-TNFα antibody (aT) treated ob/ob mice. RESULTS: Despite not differing in dietary pattern or prevalence of intestinal overgrowth, fasting ethanol levels being positively associated with measures of insulin resistance were significantly higher in children with NAFLD than in controls. Ethanol levels were similar in portal vein and chyme obtained from different parts of the GI tract between groups while ethanol levels in vena cava plasma were significantly higher in ob/ob mice. ADH activity was significantly lower in liver tissue obtained from ob/ob mice in comparison to wild-type controls and ob/ob mice treated with aT. CONCLUSIONS: Taken together, our data of animal experiments suggest that increased blood ethanol levels in patients with NAFLD may result from insulin-dependent impairments of ADH activity in liver tissue rather than from an increased endogenous ethanol synthesis. TRIAL REGISTRATION NUMBER: NCT01306396.

Wheat and barley differently affect porcine intestinal microbiota.

BACKGROUND: Diet influences the porcine intestinal microbial ecosystem. Barrows were fitted with ileal T-cannulas to compare short-term effects of eight different wheat or barley genotypes and period-to-period effects on seven bacterial groups in ileal digesta and faeces by qPCR. RESULTS: Within genotypes of wheat and barley, there was no difference (P > 0.05) in contents of analysed NSP, yet cereal types differed (P < 0.001) except for soluble arabinoxylans. Genotypes showed no effect on bacterial gene copy numbers. In ileal digesta of barley- compared to wheat-fed pigs, log10 copy numbers were lower (P < 0.05) for total eubacteria (9.6-9.8), Bacteroides-Prevotella-Porphyromonas (6.5-6.8), Clostridium cluster IV (6.7-6.9), and Roseburia spp. (6.6-7.2), while higher copy numbers were found for Lactobacillus spp. (9.4-8.8). Enterobacteriaceae (7.0-7.8) and Bifidobacterium spp. (7.0-7.7) were lower (P < 0.001) in faeces of barley compared to wheat-fed pigs. Ileal eubacteria, Clostridium cluster IV and Roseburia spp. linearly increased from period 1 to 8 for both cereals (P < 0.05). CONCLUSION: Wheat and barley differently influence microbial composition particularly in the small intestine, with barley increasing the Lactobacillus spp.:Enterobacteriaceae ratio, underlining its potential to beneficially manipulate the intestinal microbial ecosystem.

The impact of phosphorus on the immune system and the intestinal microbiota with special focus on the pig.

There is increasing interest in dietary ingredients that are appropriate to support digestive and immune functions, but also maintain a stable microbial ecosystem in the gastrointestinal tract (GIT), particularly in weaned pigs. P is an essential nutrient for both microbes and their host, as it is involved, for example, in bone formation, energy metabolism, cellular signalling and stabilisation of cell membranes. Non-ruminant animals have limited access to phytate, the main storage form of P in plant seeds. The release of P bound to phytate requires phytase activity of plant or microbial origin, resulting in the formation of variable phosphorylated inositol phosphates (InsPs). The present review focuses on interactions between variations in dietary P supply, the immune system of the host, and the intestinal microbial ecosystem. Although results on the interaction between P and the immune system are inconsistent, several studies in different species have shown a positive impact of dietary P and phytase addition on the adaptive immune response. Recent studies with pigs suggest that P supply may influence intestinal microbial composition and activity. Individual InsPs or phosphate may also affect properties of pathogenic micro-organisms, such as metabolism or virulence. In conclusion, P may be considered as part of an integrated approach to support immune functions and maintain a stable microbial ecosystem in the GIT, thereby providing a barrier against potential pathogens. Within this regard, differences in phytate-P content and intrinsic phytase activity of plant feedstuffs, as well as the formation of individual InsPs, have to be taken into account.

Antitumor immune responses induced by ionizing irradiation and further immune stimulation.

The therapy of cancer emerged as multimodal treatment strategy. The major mode of action of locally applied radiotherapy (RT) is the induction of DNA damage that triggers a network of events that finally leads to tumor cell cycle arrest and cell death. Along with this, RT modifies the phenotype of the tumor cells and their microenvironment. Either may contribute to the induction of specific and systemic antitumor immune responses. The latter are boosted when additional immune therapy (IT) is applied at distinct time points during RT. We will focus on therapy-induced necrotic tumor cell death that is immunogenic due to the release of damage-associated molecular patterns. Immune-mediated distant bystander (abscopal) effects of RT when combined with dendritic cell-based IT and the role of fractionation of radiation in the induction of immunogenic tumor cell death will be discussed. Autologous whole-tumor-cell-based vaccines generated by high hydrostatic pressure technology will be introduced and the influence of cytokines and the immune modulator AnnexinA5 on the ex vivo generated or in situ therapy-induced vaccine efficacy will be outlined. RT should be regarded as immune adjuvant for metastatic disease and as a tool for the generation of an in situ vaccine when applied at distinct fractionation doses or especially in combination with IT to generate immune memory against the tumor. To identify the most beneficial combination and chronology of RT with IT is presumably one of the biggest challenges of innovative tumor research and therapies.

Effect of dietary protein supply originating from soybean meal or casein on the intestinal microbiota of piglets.

Dietary composition is a major factor influencing the intestinal microbial ecosystem of pigs. To alleviate weaning-associated disorders, variations in dietary protein supply may beneficially affect microbial composition in the gastrointestinal tract of piglets. A total of 48 piglets, fitted with simple ileal T-cannulas, was used to examine the effect of protein supply of either highly digestible casein or less digestible, fiber-rich soybean meal (SBM) on the composition of the intestinal microbiota. Gene copies of 7 bacteria groups were determined by real-time PCR in ileal digesta and feces. Ileal counts of total eubacteria, the Bacteroides-Prevotella-Porphyromonas group, Enterobacteriaceae and Clostridium Cluster XIVa were higher (P < 0.001) in the casein-based diets. Fecal counts of all analyzed bacterial groups were higher for the SBM-based diets (P < 0.001), apart from Enterobacteriaceae (P < 0.05) which were higher in the casein-based diets. Ileal counts of lactobacilli linearly increased as the crude protein level was increased up to 335 g/kg (P < 0.01). The Bacteroides-Prevotella-Porphyromonas group linearly decreased in ileal samples (P < 0.01) and increased in fecal samples (P < 0.05) as the crude protein level in the SBM-based diet was increased. Both, protein level and protein source may affect intestinal microbial balance. Higher dietary protein levels in combination with diets low in fiber contents might stimulate proliferation of protein fermenting bacteria in piglet's large intestine. Further studies are warranted to clarify, whether this would be associated with intestinal disturbances.

Developmental effect of RASopathy mutations on neuronal network activity on a chip.

RASopathies are a group of genetic disorders caused by mutations in genes encoding components and regulators of the RAS/MAPK signaling pathway, resulting in overactivation of signaling. RASopathy patients exhibit distinctive facial features, cardiopathies, growth and skeletal abnormalities, and varying degrees of neurocognitive impairments including neurodevelopmental delay, intellectual disabilities, or attention deficits. At present, it is unclear how RASopathy mutations cause neurocognitive impairment and what their neuron-specific cellular and network phenotypes are. Here, we investigated the effect of RASopathy mutations on the establishment and functional maturation of neuronal networks. We isolated cortical neurons from RASopathy mouse models, cultured them on multielectrode arrays and performed longitudinal recordings of spontaneous activity in developing networks as well as recordings of evoked responses in mature neurons. To facilitate the analysis of large and complex data sets resulting from long-term multielectrode recordings, we developed MATLAB-based tools for data processing, analysis, and statistical evaluation. Longitudinal analysis of spontaneous network activity revealed a convergent developmental phenotype in neurons carrying the gain-of-function Noonan syndrome-related mutations Ptpn11 D61Y and Kras V14l. The phenotype was more pronounced at the earlier time points and faded out over time, suggesting the emergence of compensatory mechanisms during network maturation. Nevertheless, persistent differences in excitatory/inhibitory balance and network excitability were observed in mature networks. This study improves the understanding of the complex relationship between genetic mutations and clinical manifestations in RASopathies by adding insights into functional network processes as an additional piece of the puzzle.

Hydroxynorketamine, but not ketamine, acts via α7 nicotinic acetylcholine receptor to control presynaptic function and gene expression.

Ketamine is clinically used fast-acting antidepressant. Its metabolite hydroxynorketamine (HNK) shows a robust antidepressant effect in animal studies. It is unclear, how these chemically distinct compounds converge on similar neuronal effects. While KET acts mostly as N-methyl-d-aspartate receptor (NMDAR) antagonist, the molecular target of HNK remains enigmatic. Here, we show that KET and HNK converge on rapid inhibition of glutamate release by reducing the release competence of synaptic vesicles and induce nuclear translocation of pCREB that controls expression of neuroplasticity genes connected to KET- and HNK-mediated antidepressant action. Ro25-6981, a selective antagonist of GluN2B, mimics effect of KET indicating that GluN2B-containing NMDAR might mediate the presynaptic effect of KET. Selective antagonist of α7 nicotinic acetylcholine receptors (α7nAChRs) or genetic deletion of Chrna7, its pore-forming subunit, fully abolishes HNK-induced synaptic and nuclear regulations, but leaves KET-dependent cellular effects unaffected. Thus, KET or HNK-induced modulation of synaptic transmission and nuclear translocation of pCREB can be mediated by selective signaling via NMDAR or α7nAChRs, respectively. Due to the rapid metabolism of KET to HNK, it is conceivable that subsequent modulation of glutamatergic and cholinergic neurotransmission affects circuits in a cell-type-specific manner and contributes to the therapeutic potency of KET. This finding promotes further exploration of new combined medications for mood disorders.

The dynamics of the female microbiome: unveiling abrupt changes of microbial domains across body sites from prepartum to postpartum phases.

The microbial ecosystem of women undergoes enormous changes during pregnancy and the perinatal period. Little is known about the extent of changes in the maternal microbiome beyond the vaginal cavity and its recovery after birth. In this study, we followed pregnant women [maternal prepartum (mpre), n = 30] into the postpartum period [1 month postpartum, maternal postpartum (mpost), n = 30]. We profiled their oral, urinary, and vaginal microbiome; archaeome; mycobiome; and urinary metabolome and compared them with those of nonpregnant (np) women (n = 29). Overall, pregnancy status (np, mpre, and mpost) had a smaller effect on the microbiomes than body site, but massive transitions were observed for the oral and urogenital (vaginal and urinary) microbiomes. While the oral microbiome fluctuates during pregnancy but stabilizes rapidly within the first month postpartum, the urogenital microbiome is characterized by a major remodeling caused by a massive loss of Lactobacillus and thus a shift from Vaginal Community State Type (CST) I (40% of women) to CST IV (85% of women). The urinary metabolome rapidly reached an np-like composition after delivery, apart from lactose and oxaloacetic acid, which were elevated during active lactation. Fungal and archaeal profiles were indicative of pregnancy status. Methanobacterium signatures were found mainly in np women, and Methanobrevibacter showed an opposite behavior in the oral cavity (increased) and vagina (decreased) during pregnancy. Our findings suggest that the massive remodeling of the maternal microbiome and metabolome needs more attention and that potential interventions could be envisioned to optimize recovery and avoid long-term effects on maternal health and subsequent pregnancies. IMPORTANCE: The perinatal microbiome is of specific interest for the health of the mother and infant. We therefore investigate the dynamics of the female microbiome from nonpregnant over prepartum to the postpartum period in urine and the oral and vaginal cavities. A specific focus of this study is put not only on the bacterial part of the microbiome but also on the underinvestigated contribution of fungi and archaea. To our knowledge, we present the first study highlighting those aspects. Our findings suggest that the massive remodeling of the maternal microbiome and metabolome needs more attention and that potential interventions could be envisioned to optimize recovery and avoid long-term effects on maternal health and subsequent pregnancies.

HIV-2 genome dimerization is required for the correct processing of Gag: a second-site reversion in matrix can restore both processes in dimerization-impaired mutant viruses.

A unique feature of retroviruses is the packaging of two copies of their genome, noncovalently linked at their 5' ends. In vitro, dimerization of human immunodeficiency virus type 2 (HIV-2) RNA occurs by interaction of a self-complementary sequence exposed in the loop of stem-loop 1 (SL-1), also termed the dimer initiation site (DIS). However, in virions, HIV-2 genome dimerization does not depend on the DIS. Instead, a palindrome located within the packaging signal (Psi) is the essential motif for genome dimerization. We reported previously that a mutation within Psi decreasing genome dimerization and packaging also resulted in a reduced proportion of mature particles (A. L'Hernault, J. S. Greatorex, R. A. Crowther, and A. M. Lever, Retrovirology 4:90, 2007). In this study, we investigated further the relationship between HIV-2 genome dimerization, particle maturation, and infectivity by using a series of targeted mutations in SL-1. Our results show that disruption of a purine-rich ((392)-GGAG-(395)) motif within Psi causes a severe reduction in genome dimerization and a replication defect. Maintaining the extended SL-1 structure in combination with the (392)-GGAG-(395) motif enhanced packaging. Unlike that of HIV-1, which can replicate despite mutation of the DIS, HIV-2 replication depends critically on genome dimerization rather than just packaging efficiency. Gag processing was altered in the HIV-2 dimerization mutants, resulting in the accumulation of the MA-CA-p2 processing intermediate and suggesting a link between genome dimerization and particle assembly. Analysis of revertant SL-1 mutant viruses revealed that a compensatory mutation in matrix (70TI) could rescue viral replication and partially restore genome dimerization and Gag processing. Our results are consistent with interdependence between HIV-2 RNA dimerization and the correct proteolytic cleavage of the Gag polyprotein.

Foxp3-mediated suppression of CD95L expression confers resistance to activation-induced cell death in regulatory T cells.

CD4(+)CD25(++)Foxp3(+) regulatory T cells (Tregs) control self-reactive cells to maintain peripheral tolerance. Treg homeostasis has to be controlled tightly to ensure balanced Treg-mediated suppression. One mechanism that regulates the CD4(+) T cell pool is activation-induced cell death (AICD). This is mimicked in vitro by TCR restimulation-induced expression of the death ligand CD95L (FasL/APO-1L/CD178) in expanded T cells. These cells express the death receptor CD95 (Fas/APO-1), and binding of CD95L to CD95 results in AICD. In contrast, Tregs do not undergo AICD upon TCR (re)stimulation in vitro despite a functional CD95 cell death pathway. In this study, we show that human and murine Tregs express low levels of CD95L upon stimulation. Knockdown of the transcriptional repressor Foxp3 partially rescues CD95L expression and AICD in human Tregs. Moreover, upon stimulation Foxp3-mutant Tregs from Scurfy mice express CD95L similar to conventional T cells. We further addressed whether exogenous CD95 stimulation provides a mechanism of Treg homeostatic control in vivo in mice. Triggering of CD95 reduced Treg numbers systemically as reflected by in vivo imaging and decreased GFP(+) Treg numbers ex vivo. Our study reveals that Foxp3 negatively regulates CD95L expression in Tregs and demonstrates that Tregs are susceptible to homeostatic control by CD95 stimulation.

Use of pigs as a potential model for research into dietary modulation of the human gut microbiota.

The human intestinal microbial ecosystem plays an important role in maintaining health. A multitude of diseases including diarrhoea, gastrointestinal inflammatory disorders, such as necrotising enterocolitis (NEC) of neonates, and obesity are linked to microbial composition and metabolic activity. Therefore, research on possible dietary strategies influencing microbial composition and activity, both preventive and curative, is being accomplished. Interest has focused on pre- and probiotics that stimulate the intestinal production of beneficial bacterial metabolites such as butyrate, and beneficially affect microbial composition. The suitability of an animal model to study dietary linked diseases is of much concern. The physiological similarity between humans and pigs in terms of digestive and associated metabolic processes places the pig in a superior position over other non-primate models. Furthermore, the pig is a human-sized omnivorous animal with comparable nutritional requirements, and shows similarities to the human intestinal microbial ecosystem. Also, the pig has been used as a model to assess microbiota-health interactions, since pigs exhibit similar syndromes to humans, such as NEC and partly weanling diarrhoea. In contrast, when using rodent models to study diet-microbiota-health interactions, differences between rodents and humans have to be considered. For example, studies with mice and human subjects assessing possible relationships between the composition and metabolic activity of the gut microbiota and the development of obesity have shown inconsistencies in results between studies. The present review displays the similarities and differences in intestinal microbial ecology between humans and pigs, scrutinising the pig as a potential animal model, with regard to possible health effects.

Enhanced recovery after cesarean section (ERAC): Where are we in Austria?

OBJECTIVE: Enhanced recovery after surgery (ERAS) recommendations for cesarean section (ERAC), likely the most common reason for laparotomy in women, were issued in 2018-19. We examined how current perioperative management at cesarean section in Austrian hospitals aligns with ERAS recommendations. STUDY DESIGN: We surveyed the 21 largest public obstetric units in Austria for alignment with 20 of the 31 strong ERAS recommendations regarding perioperative maternal care at cesarean section. We also looked at how the German-language clinical guideline for cesarean section (AWMF Guideline Sectio caesarea) aligns with ERAS recommendations. RESULTS: The 21 obstetric units cared for about 51% of all births in Austria in 2019. Cesarean section rates ranged from 17.7% to 50.4%. All 21 units implemented the five strong recommendations regarding patient information and counselling, regional anesthesia, euvolemia and multimodal analgesia. The least implemented strong recommendation was the one for the use of pneumatic compression stockings to prevent thromboembolic disease (0/21 units). Overall, all 21 units implemented ≥11 and 13 (62%) implemented ≥15 (≥75%) of the 20 strong recommendations; no unit implemented all 20 strong recommendations. There were no differences in the implementation of strong recommendations according to hospital volume. CONCLUSIONS: Even in the absence of formal adoption of ERAS program for cesarean section many perioperative ERAS recommendations are already implemented in Austria. The least implemented recommendations were the use of pneumatic compression stockings (0 of 21 units) and immediate catheter removal (4 of 21 units). Only 10 of the 20 ERAS recommendations we looked at are included in the current German-language clinical guideline for cesarean section.