[Why teams in charge of children after a pediatric intensive care unit stay do not take into account the treatment limitation decisions previously made by intensivists].

International audienceThe medical reasoning model that is used for LTDs in the PICU generates conflictual situations when compared to the models that are used in other specialties. These models represent various expressions of subjectivity, as in any medical decision. Acknowledging this fact could facilitate its integration into clinical practice and should improve authentic debates that are necessary to ensure continuity of care for these children

Assessment of endocrine disruptor impacts on lipid metabolism in a fatty acid-supplemented HepaRG human hepatic cell line

International audienceThe incidence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing worldwide. This disease encompasses several stages, from steatosis to steatohepatitis and, eventually, to fibrosis and cirrhosis. Exposure to environmental contaminants is one of the risk factors and an increasing amount of evidence points to a role for endocrine disrupting compounds (EDCs). This study assesses the impact of selected EDCs on the formation of lipid droplets, the marker for steatosis in a hepatic model. The mechanisms underlying this effect are then explored. Ten compounds were selected according to their obesogenic properties: bisphenol A, F and S, butyl-paraben, cadmium chloride, p,p'-DDE, DBP, DEHP, PFOA and PFOS. Using a 2D or 3D model, HepaRG cells were exposed to the compounds with or without fatty acid supplementation. Then, the formation of lipid droplets was quantified by an automated fluorescence-based method. The expression of genes and proteins involved in lipid metabolism and the impact on cellular respiration was analyzed. The formation of lipid droplets, which is revealed or enhanced by oleic acid supplementation, was most effectively induced by p,p'-DDE and DEHP. Experiments employing either 2D or 3D culture conditions gave similar results. Both compounds induced the expression of PLIN2. p,p'-DDE also appears to act by decreasing in fatty acid oxidation. Some EDCs were able to induce the formation of lipid droplets, in HepaRG cells, an effect which was increased after supplementation of the cells with oleic acid. A full understanding of the mechanisms of these effects will require further investigation. The novel automated detection method described here may also be useful in the future as a regulatory test for EDC risk assessment

Exposure to metal oxide nanoparticles administered at occupationally relevant doses induces pulmonary effects in mice

International audienceIn spite of the great promises that the development of nanotechnologies can offer, concerns regarding potential adverse health effects of occupational exposure to nanoparticle (NP) is raised. We recently identified metal oxide NP in lung tissue sections of welders, located inside macrophages infiltrated in fibrous regions. This suggests a role of these NP in the lung alterations observed in welders. We therefore designed a study aimed to investigate the pulmonary effects, in mice, of repeated exposure to NP administered at occupationally relevant doses. We therefore chose four metal oxide NPs representative of those found in the welder’s lungs: Fe2O3, Fe3O4, MnFe2O4 and CrOOH. These NPs were administered weekly for up to 3 months at two different doses: 5 μg, chosen as occupationally relevant to welding activity, and 50 μg, chosen as occupationally relevant to the context of an NP-manufacturing facility. Our results show that 3 month-repeated exposures to 5 μg NP induced limited pulmonary effects, characterized by the development of a mild peribronchiolar fibrosis observed for MnFe2O4 and CrOOH NP only. This fibrotic event was further extended in terms of intensity and localization after the repeated administration of 50 μg NP: all but Fe2O3 NP induced the development of peribronchiolar, perivascular and alveolar fibrosis, together with an interstitial inflammation. Our data demonstrate for the first time a potential risk for respiratory health posed by repeated exposure to NP at occupationally relevant doses. Given these results, the development of occupational exposure limits (OELs) specifically dedicated to NP exposure might therefore be an important issue to address

Innate Immune Responses and Rapid Control of Inflammation in African Green Monkeys Treated or Not with Interferon-Alpha during Primary SIVagm Infection

International audienceChronic immune activation (IA) is considered as the driving force of CD4 + T cell depletion and AIDS. Fundamental clues in the mechanisms that regulate IA could lie in natural hosts of SIV, such as African green monkeys (AGMs). Here we investigated the role of innate immune cells and IFN-a in the control of IA in AGMs. AGMs displayed significant NK cell activation upon SIVagm infection, which was correlated with the levels of IFN-a. Moreover, we detected cytotoxic NK cells in lymph nodes during the early acute phase of SIVagm infection. Both plasmacytoid and myeloid dendritic cell (pDC and mDC) homing receptors were increased, but the maturation of mDCs, in particular of CD16 + mDCs, was more important than that of pDCs. Monitoring of 15 cytokines showed that those, which are known to be increased early in HIV-1/SIVmac pathogenic infections, such as IL-15, IFN-a, MCP-1 and CXCL10/IP-10, were significantly increased in AGMs as well. In contrast, cytokines generally induced in the later stage of acute pathogenic infection, such as IL-6, IL-18 and TNF-a, were less or not increased, suggesting an early control of IA. We then treated AGMs daily with high doses of IFN-a from day 9 to 24 post-infection. No impact was observed on the activation or maturation profiles of mDCs, pDCs and NK cells. There was also no major difference in T cell activation or interferon-stimulated gene (ISG) expression profiles and no sign of disease progression. Thus, even after administration of high levels of IFN-a during acute infection, AGMs were still able to control IA, showing that IA control is independent of IFN-a levels. This suggests that the sustained ISG expression and IA in HIV/SIVmac infections involves non-IFN-a products

Rheumatological features of Whipple disease

International audienceWhipple disease (WD) is a rare infectious systemic disease. Rheumatologists are at the frontline of WD diagnosis due to the early rheumatological manifestations. An early diagnosis is crucial, as usual anti-rheumatic drugs, especially TNF inhibitors, may worsen the disease course. We conducted a retrospective multicentre national study from January 2010 to April 2020 to better characterize the rheumatological features of WD. Classic WD (CWD) was defined by positive periodic acid-Schiff (PAS) staining of a small-bowel biopsy sample, and non-CWD (NCWD) was defined by negative PAS staining of a small-bowel biopsy sample but at least one positive Tropheryma whipplei (TW) polymerase chain reaction (PCR) for a digestive or extradigestive specimen. Sixty-eight patients were enrolled, including 11 CWD patients. Twenty patients (30%) received TNF inhibitors during the WD course, with inefficacy or symptom worsening. More digestive symptoms and systemic biological features were observed in CWD patients than in NCWD patients, but both patient groups had similar outcomes, especially concerning the response to antibiotics and relapse rate. Stool and saliva TW PCR sensitivity were both 100% for CWD and 75% for NCWD and 89% and 60% for small-bowel biopsy sample PCR, respectively. WD encountered in rheumatology units has many presentations, which might result from different pathophysiologies that are dependent on host immunity. Given the heterogeneous presentations and the presence of chronic carriage, multiple TW PCR tests on samples from specific rheumatological sites when possible should be performed, but samples from nonspecific digestive and extradigestive sites also have great value

SARS‐CoV‐2‐related bat virus behavior in human‐relevant models sheds light on the origin of COVID‐19

International audienceBat sarbecovirus BANAL-236 is highly related to SARS-CoV-2 and infects human cells, albeit lacking the furin cleavage site in its spike protein. BANAL-236 replicates efficiently and pauci-symptomatically in humanized mice and in macaques, where its tropism is enteric, strongly differing from that of SARS-CoV-2. BANAL-236 infection leads to protection against superinfection by a virulent strain. We find no evidence of antibodies recognizing bat sarbecoviruses in populations in close contact with bats in which the virus was identified, indicating that such spillover infections, if they occur, are rare. Six passages in humanized mice or in human intestinal cells, mimicking putative early spillover events, select adaptive mutations without appearance of a furin cleavage site and no change in virulence. Therefore, acquisition of a furin site in the spike protein is likely a pre-spillover event that did not occur upon replication of a SARS-CoV-2-like bat virus in humans or other animals. Other hypotheses regarding the origin of the SARS-CoV-2 should therefore be evaluated, including the presence of sarbecoviruses carrying a spike with a furin cleavage site in bats

Evaluation of r-mamu-IFN-α efficacy in AGMs.

<p>(A) <i>In vitro</i> comparison of the induction of ISG expression in AGM (hatched green) <i>versus</i> rhesus macaques (red) PBMCs after 18 h stimulation with 10, 100 or 1000 IU/ml of r-mamu-IFN-α (n = 2 AGMs, n = 2 macaques). <i>Mx1</i> gene expression values were measured by real-time PCR and are expressed as the Log₂ (fold change relative to values before treatment). The experiment was done in triplicate. (B) IFN-α detection in the plasma of SIV-negative (hatched green) and SIV-infected (blue) AGMs after a single subcutaneous injection of 5×10⁵ IU of r-mamu-IFN-α. IFN-α was rapidly detectable in blood (1 h), but decreased after 24 h. (C) Efficient induction of ISG (<i>CXCL10</i>, <i>IP-10</i>) in the PBMC of SIV-negative (hatched green) and SIV-infected (blue) AGMs (chronic phase) after a single subcutaneous injection of 5×10⁵ IU of r-mamu-IFN-α. Gene expression was measured by real-time PCR and expressed as the Log₂ (fold change relative to values before treatment). (D) Viral load in a chronically SIV-infected AGM treated during 16 days with r-mamu-IFN-α as described in results. (E) Impact of the r-mamu-IFN-α treatment during acute infection on viral load. SIVagm-infected untreated AGMs are shown in black and IFN-α-treated in blue. Plasma viral load are reported as log₁₀ (viral RNA copies)/ml of plasma. (F) No major effect of the two weeks IFN-α treatment on T cell proliferation in an uninfected AGM and in a chronically infected AGM (same AGM as in D) as measured by flow cytometry. (G and H) No effect of the treatment during the acute phase on T cell proliferation. T cell proliferations are shown as percentage of Ki-67⁺ cells among blood (G) CD4⁺ and (H) CD8⁺ T cells. SIVagm-infected untreated AGMs are shown in black and IFN-α-treated in blue. The grey area indicates the period of treatment. The medians of treated animals were inside the interquartile range of the control untreated animals and were thus considered not different.</p

High dose of IFN-α in the acute phase of infection does not induce persistent ISG expression in AGMs.

<p>The 6 panels show the expression levels in PBMCs and LN cells of 3 ISGs: (A,B) <i>CXCL9</i>, (C,D) <i>CXCL10</i> (<i>IP-10</i>) and (E,F) <i>CXCL11</i>. Gene expression was measured by real-time PCR and expressed as the Log₂ (fold change relative to values before treatment). IFN-α treated AGMs are in blue and untreated in black. The grey area indicates the period of treatment. The medians of treated animals were inside the interquartile range of the untreated animals and were thus considered not different.</p

NK cell activation pattern and function in blood and lymph nodes upon SIVagm infection.

<p>NK cells were defined as CD45⁺ Lineage⁻ (CD3, CD20, HLA-DR) CD8α⁺ NKG2A⁺ CD16^+/−. The major NK cell populations were CD16⁺ in blood and CD16⁻ in LNs (<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004241#ppat.1004241.s001" target="_blank">Figure S1</a>). (A) Absolute numbers of NK cells in blood and (B) frequencies among CD45⁺ LN cells throughout SIVagm infection. Frequencies of (C, D) proliferating (Ki-67⁺) and (E, F) activated (CD69⁺) NK cells in blood (left panels) and LNs (right panels). Cytotoxicity was estimated by measuring the frequency of degranulating cells (CD107a⁺ cells) in (G) blood and (H) LNs. The level of cytokine production was assessed by direct <i>ex vivo</i> intra-cellular staining of the frequency of IFN-gamma in NK cells from (I) blood and (J) LN. Data are presented as medians and interquartile ranges (n = 6 AGMs). Day zero represents the median of all the time points before infection. See legend to <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004241#ppat-1004241-g002" target="_blank">Figure 2</a> for a description of p-values (logarithm transformation for panel B, C and G).</p