SOD1 is a synthetic-lethal target in PPM1D-mutant leukemia cells.

The DNA damage response is critical for maintaining genome integrity and is commonly disrupted in the development of cancer. PPM1D (protein phosphatase Mg2+/Mn2+-dependent 1D) is a master negative regulator of the response; gain-of-function mutations and amplifications of PPM1D are found across several human cancers making it a relevant pharmacological target. Here, we used CRISPR/Cas9 screening to identify synthetic-lethal dependencies of PPM1D, uncovering superoxide dismutase-1 (SOD1) as a potential target for PPM1D-mutant cells. We revealed a dysregulated redox landscape characterized by elevated levels of reactive oxygen species and a compromised response to oxidative stress in PPM1D-mutant cells. Altogether, our results demonstrate a role for SOD1 in the survival of PPM1D-mutant leukemia cells and highlight a new potential therapeutic strategy against PPM1D-mutant cancers.

SOD1 is a synthetic lethal target in PPM1D-mutant leukemia cells.

The DNA damage response is critical for maintaining genome integrity and is commonly disrupted in the development of cancer. PPM1D (protein phosphatase, Mg2+/Mn2+ dependent 1D) is a master negative regulator of the response; gain-of-function mutations and amplifications of PPM1D are found across several human cancers making it a relevant pharmacologic target. Here, we used CRISPR/Cas9 screening to identify synthetic-lethal dependencies of PPM1D, uncovering superoxide dismutase-1 (SOD1) as a potential target for PPM1D-mutant cells. We revealed a dysregulated redox landscape characterized by elevated levels of reactive oxygen species and a compromised response to oxidative stress in PPM1D-mutant cells. Altogether, our results demonstrate the protective role of SOD1 against oxidative stress in PPM1D-mutant leukemia cells and highlight a new potential therapeutic strategy against PPM1D-mutant cancers.

Liver transient elastography values in healthy South African children.

BACKGROUND: Transient elastography (TE) is a rapid noninvasive ultrasound-based technology that measures liver stiffness as a surrogate for liver fibrosis and controlled attenuation parameter (CAP) as a measure of liver steatosis. However, normal ranges in children are not well defined in all populations. The aim of this study was to determine transient elastography values in healthy South African children. METHODS: From April 2019 to December 2021, children were recruited from the HIV negative control group of a cohort study. Only children neither overweight nor obese, without evidence of liver disease, no medical condition or medication associated with hepatic steatosis or fibrosis and normal metabolic profile were included in this cross-sectional analysis. Clinical data, anthropometry and blood samples were collected on the same day as transient elastography with controlled attenuation parameter was performed. RESULTS: 104 children (median age 12.8 years [IQR 11.4-14.8, range 7.9-17.7 years]; 59 [57%] boys) were included. Liver stiffness was positively correlated with age (Pearson's r = 0.39, p < 0.001). Median liver stiffness in boys (5.2 kPa [5th to 95th percentiles 3.6 to 6.8 kPa]) was greater than in girls (4.6 kPa [5th to 95th percentiles 3.6 to 6.1 kPa; p = 0.004]), but there was no difference by ethnicity. Median CAP was 179dB/m (5th to 95th percentiles 158 to 233dB/m). There was a positive correlation between CAP and body mass index (BMI) z-score, but no difference by age, sex, ethnicity or pubertal status. CONCLUSION: Liver stiffness values increase with age and are higher in healthy South African boys than girls, whereas CAP values vary with BMI, but not with age or sex.

Impact of Neurons on Patient-Derived Cardiomyocytes Using Organ-On-A-Chip and iPSC Biotechnologies.

In the heart, cardiac function is regulated by the autonomic nervous system (ANS) that extends through the myocardium and establishes junctions at the sinus node and ventricular levels. Thus, an increase or decrease in neuronal activity acutely affects myocardial function and chronically affects its structure through remodeling processes. The neuro-cardiac junction (NCJ), which is the major structure of this system, is poorly understood and only a few cell models allow us to study it. Here, we present an innovant neuro-cardiac organ-on-chip model to study this structure to better understand the mechanisms involved in the establishment of NCJ. To create such a system, we used microfluidic devices composed of two separate cell culture compartments interconnected by asymmetric microchannels. Rat PC12 cells were differentiated to recapitulate the characteristics of sympathetic neurons, and cultivated with cardiomyocytes derived from human induced pluripotent stem cells (hiPSC). We confirmed the presence of a specialized structure between the two cell types that allows neuromodulation and observed that the neuronal stimulation impacts the excitation-contraction coupling properties including the intracellular calcium handling. Finally, we also co-cultivated human neurons (hiPSC-NRs) with human cardiomyocytes (hiPSC-CMs), both obtained from the same hiPSC line. Hence, we have developed a neuro-cardiac compartmentalized in vitro model system that allows us to recapitulate the structural and functional properties of the neuro-cardiac junction and that can also be used to better understand the interaction between the heart and brain in humans, as well as to evaluate the impact of drugs on a reconstructed human neuro-cardiac system.

Genuine selective caspase-2 inhibition with new irreversible small peptidomimetics.

Caspase-2 (Casp2) is a promising therapeutic target in several human diseases, including nonalcoholic steatohepatitis (NASH) and Alzheimer's disease (AD). However, the design of an active-site-directed inhibitor selective to individual caspase family members is challenging because caspases have extremely similar active sites. Here we present new peptidomimetics derived from the VDVAD pentapeptide structure, harboring non-natural modifications at the P2 position and an irreversible warhead. Enzyme kinetics show that these new compounds, such as LJ2 or its specific isomers LJ2a, and LJ3a, strongly and irreversibly inhibit Casp2 with genuine selectivity. In agreement with the established role of Casp2 in cellular stress responses, LJ2 inhibits cell death induced by microtubule destabilization or hydroxamic acid-based deacetylase inhibition. The most potent peptidomimetic, LJ2a, inhibits human Casp2 with a remarkably high inactivation rate (k3/Ki ~5,500,000 M-1 s-1), and the most selective inhibitor, LJ3a, has close to a 1000 times higher inactivation rate on Casp2 as compared to Casp3. Structural analysis of LJ3a shows that the spatial configuration of Cα at the P2 position determines inhibitor efficacy. In transfected human cell lines overexpressing site-1 protease (S1P), sterol regulatory element-binding protein 2 (SREBP2) and Casp2, LJ2a and LJ3a fully inhibit Casp2-mediated S1P cleavage and thus SREBP2 activation, suggesting a potential to prevent NASH development. Furthermore, in primary hippocampal neurons treated with ß-amyloid oligomers, submicromolar concentrations of LJ2a and of LJ3a prevent synapse loss, indicating a potential for further investigations in AD treatment.

PIDDosome-SCAP crosstalk controls high-fructose-diet-dependent transition from simple steatosis to steatohepatitis.

Sterol deficiency triggers SCAP-mediated SREBP activation, whereas hypernutrition together with ER stress activates SREBP1/2 via caspase-2. Whether these pathways interact and how they are selectively activated by different dietary cues are unknown. Here, we reveal regulatory crosstalk between the two pathways that controls the transition from hepatosteatosis to steatohepatitis. Hepatic ER stress elicited by NASH-inducing diets activates IRE1 and induces expression of the PIDDosome subunits caspase-2, RAIDD, and PIDD1, along with INSIG2, an inhibitor of SCAP-dependent SREBP activation. PIDDosome assembly activates caspase-2 and sustains IRE1 activation. PIDDosome ablation or IRE1 inhibition blunt steatohepatitis and diminish INSIG2 expression. Conversely, while inhibiting simple steatosis, SCAP ablation amplifies IRE1 and PIDDosome activation and liver damage in NASH-diet-fed animals, effects linked to ER disruption and preventable by IRE1 inhibition. Thus, the PIDDosome and SCAP pathways antagonistically modulate nutrient-induced hepatic ER stress to control non-linear transition from simple steatosis to hepatitis, a key step in NASH pathogenesis.

Description of a new species from Clarias maclareni and phylogenetical analysis of Quadriacanthus (Monogenea, Dactylogyridae) species transfers between clariid and non-clariid fish hosts in Cameroon.

Recently in Cameroon, two species belonging to Quadriacanthus: Q. anaspidoglanii Akoumba, Tombi & Bilong Bilong, 2017 and Q. euzeti Nack, Pariselle & Bilong Bilong, 2016 have been recorded on gill filaments of Notoglanidium macrostoma (Siluriformes, Claroteidae) in the Memou'ou River (Nyong Basin) and Papyrocranus afer (Osteoglossiformes, Notopteridae) in Lake Ossa, respectively. These records have been considered the result of lateral transfers from Clariidae to a Claroteidae host for the first case (parasitism of N. macrostoma by Q. anaspidoglanii) and from Clariidae or Bagridae to a Notopteridae host for the second (parasitism of P. afer by Q. euzeti). In this paper, the investigation of interspecific relationships among Quadriacanthus spp. parasitizing Clariidae, Bagridae, Claroteidae and Notopteridae in Cameroon resulted in the record of Q. anaspidoglanii from N. macrostoma, Q. euzeti from P. afer, a new record of Q. levequei Birgi, 1988 from Clarias jaensis in the Nyong River, and the description of Q. barombiensis n. sp. from Clarias maclareni in Lake Barombi Mbo. The newly identified species is characterized by having an accessory piece ending in one small hook and the median expansion of its dorsal bar with two filaments. Phylogenetic analysis based on 28S rDNA sequences confirms that the Quadriacanthus spp. parasitizing gill filaments of non-clariid hosts in Cameroon originate from lateral transfers from clariid fishes, and that Clariidae are ancestral hosts of these monogenean species.

Title: Description d'une nouvelle espèce parasite de Clarias maclareni et analyse phylogénétique des transferts d'espèces de Quadriacanthus (Monogenea, Dactylogyridae) entre poissons hôtes clariidés et non clariidés au Cameroun. Abstract: Récemment au Cameroun deux espèces appartenant à Quadriacanthus : Q. anaspidoglanii Akoumba, Tombi & Bilong Bilong, 2017 et Q. euzeti Nack, Pariselle & Bilong Bilong, 2016 ont été signalées, respectivement sur les filaments branchiaux de Notoglanidium macrostoma (Siluriformes, Claroteidae), dans la rivière Memou'ou (bassin du Nyong) et Papyrocranus afer (Osteoglossiformes, Notopteridae) dans le lac Ossa. Ces signalements ont été considérés comme le résultat de transferts latéraux de Clariidae vers un hôte Claroteidae pour le premier cas (parasitisme de N. macrostoma par Q. anaspidoglanii) et d'un Clariidae ou Bagridae vers un hôte Notopteridae pour le second (parasitisme de P. afer par Q. euzeti). Dans cet article, l'étude des relations interspécifiques entre Quadriacanthus spp. parasitant des Clariidae, Bagridae, Claroteidae et Notopteridae au Cameroun a abouti au signalement de Q. anaspidoglanii chez N. macrostoma, Q. euzeti chez P. afer, un nouveau signalement de Q. levequei Birgi, 1988 chez Clarias jaensis dans le fleuve Nyong, et à la description de Q. barombiensis n. sp. chez Clarias maclareni dans le lac Barombi Mbo. L'espèce nouvellement identifiée se caractérise par la présence d'une pièce accessoire se terminant par un petit crochet et l'expansion médiane de sa barre dorsale avec deux filaments. L'analyse phylogénétique basée sur les séquences d'ADNr 28S confirme que les Quadriacanthus spp. des filaments branchiaux parasitant des hôtes non-clariidés au Cameroun proviennent de transferts latéraux de poissons clariidés, et que les Clariidae sont bien les hôtes ancestraux de ces espèces de monogènes.

Prevalence and Risk Factors for Hepatic Steatosis in Children With Perinatal HIV on Early Antiretroviral Therapy Compared to HIV-Exposed Uninfected and HIV-Unexposed Children.

Objectives: We evaluated the prevalence and risk factors for hepatic steatosis in South African children with perinatally acquired HIV (PHIV) who started treatment early and remain on long-term antiretroviral therapy (ART) compared to HIV-uninfected children. Design: A cross-sectional study from April 2019 to October 2021. PHIV, HIV-exposed uninfected (HEU) and HIV-unexposed (HU) children were enrolled from an ongoing cohort study. Methods: All children had transient elastography (TE) with controlled attenuation parameter (CAP). Liver enzymes, lipogram, insulin and glucose were sent after an overnight fast. Multivariable linear regression analyses identified predictors of CAP. Hepatic steatosis was defined as CAP>248kPa. Results: 215 children (111 [52%] male; median age 14.1 years; IQR 12.7-14.9) participated in the study, 110 PHIV, 105 HIV-uninfected (36 HEU, 69 HU). PHIV initiated ART at a median age of 2.7 months (IQR 1.8-8.5). Hepatic steatosis prevalence was 9% in PHIV, 3% in HEU and 1% in HU children (p = 0.08). However, 8% of lean (body mass index z-score ≤ +1) PHIV had hepatic steatosis compared to zero lean HEU or HU children (p = 0.03). In multivariable linear regression analysis of all PHIV, body mass index (BMI) z-score was positively associated with CAP (p = 0.001) while CD4 count (p = 0.02) and duration of suppression of HIV viraemia (p = 0.009) were negatively associated with CAP, adjusting for age, sex and ethnicity. Conclusions: Hepatic steatosis prevalence was higher in lean PHIV than lean HIV-uninfected South African children. Longer suppression of HIV viraemia and higher CD4 count were associated with lower CAP and might be protective factors for hepatic steatosis in PHIV children.

Abdominal Involvement in Children With Bacteriologically Confirmed Tuberculosis: A Five-year Experience From Cape Town, South Africa.

BACKGROUND: Abdominal tuberculosis (TB) in children is poorly described and often poses a diagnostic challenge. We evaluated abdominal involvement in children presenting with bacteriologically confirmed TB. METHODS: We undertook a retrospective study at Tygerberg Hospital, Cape Town, from January 1, 2014, through December 31, 2018, of all children (<13 years) diagnosed with bacteriologically confirmed TB, in whom abdominal involvement was found. Demographic and clinical data were collected through folder review, laboratory records and imaging reports. RESULTS: Of 966 children with bacteriologically confirmed TB, 111 (11.5%) had abdominal involvement; 16 (14.4%) were excluded from further analysis because of lack of clinical data. The median age of the remaining 95 children was 43 months (interquartile range 20-94); 26 (27%) were HIV positive. The main gastrointestinal symptoms/signs were weight loss (84.2%), abdominal distention (54.7%), hepatomegaly (60.0%) and abdominal pain (26.3%). The main pathologic types were intra-abdominal lymph nodes (68.4%), solid organ involvement (54.7%), peritoneal type (23.2%) and intestinal type (10.5%). Splenic abscesses and solid organ involvement on ultrasonography were more common in HIV-positive children (P < 0.001 and P = 0.008, respectively). Liver abscesses were associated with age less than 5 years (P = 0.03), while abdominal lymphadenopathy on ultrasonography was more common in children older than 5 years (P = 0.038). Abdominal specimens were collected in an attempt to identify Mycobacterium tuberculosis in 15 of 95 (15.8%) patients and were positive in 13 of 15 (86.7%). CONCLUSIONS: Over 10% of children with confirmed TB had abdominal involvement. Abdominal TB should be considered in any pediatric TB case with abdominal symptoms, and ultrasonography should be the radiologic study of choice.

Abdominal Tuberculosis in Children: Challenges, Uncertainty, and Confusion.

The diagnosis of abdominal tuberculosis (TB) is challenging, and the prevalence of abdominal TB in children is likely underestimated. It may present with nonspecific abdominal symptoms and signs, but children who present with pulmonary TB may have additional abdominal subclinical involvement. Diagnosis is specifically challenging because none of the available diagnostic tools provide adequate sensitivity and specificity. In this review, we summarize the best available evidence on abdominal TB in children, covering the epidemiology, pathogenesis, clinical presentation, diagnosis, and treatment. We propose a diagnostic approach that could be followed for symptomatic children. We believe that a combination of investigations could be useful to both aid diagnosis and define the extent of the disease, and we propose that abdominal ultrasound should be used more frequently in children with possible TB and any abdominal symptoms. This neglected disease has received little attention to date, and further research is warranted.

CXCR5 and ICOS expression identifies a CD8 T-cell subset with TFH features in Hodgkin lymphomas.

A better characterization of T-cell subsets in the microenvironment of classical Hodgkin lymphoma (cHL) would help to develop immunotherapies. Using multicolor flow cytometry, we identified in 6 of 43 cHL tissue samples a previously unrecognized subset of CD8 T cells coexpressing CXCR5 and inducible T-cell costimulator (ICOS) molecules (CD8CXCR5+ICOS+). These cells shared phenotypic features with follicular helper T (TFH) cells including low CCR7 expression together with high expression of B-cell lymphoma-6, programmed cell death 1, B and T lymphocyte attenuator, CD200, and OX40. They had deficient cytotoxicity, low interferon-γ secretion, and common functional properties with intratumoral CD4+ TFH cells, such as production of interleukin-4 (IL-4), IL-21, CXCL13, and capacity to sustain B cells. Gene profiling analysis showed a significant similarity between the signatures of CD8CXCR5+ICOS+ T cells and CD4+ TFH cells. Benign lymphadenitis tissues (n = 8) were devoid of CD8CXCR5+ICOS+ cells. Among the 35 B-cell lymphoma tissues analyzed, including follicular lymphomas (n = 13), diffuse large cell lymphomas (n = 12), marginal zone lymphomas (MZLs; n = 3), mantle cell lymphomas (n = 3), and chronic lymphocytic leukemias (n = 4), only 1 MZL sample contained CD8CXCR5+ICOS+ cells. Lymphoma tumors with CD8CXCR5+ICOS+ cells shared common histopathological features including residual germinal centers, and contained high amounts of activated CD8CXCR5-ICOS+ cells. These data demonstrate a CD8 T-cell differentiation pathway leading to the acquisition of some TFH similarities. They suggest a particular immunoediting process with global CD8 activation acting mainly, but not exclusively, in HL tumors.

Pancreatic Ductal Adenocarcinoma: A Strong Imbalance of Good and Bad Immunological Cops in the Tumor Microenvironment.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal cancers with very few available treatments. For many decades, gemcitabine was the only treatment for patients with PDAC. A recent attempt to improve patient survival by combining this chemotherapy with FOLFIRINOX and nab-paclitaxel failed and instead resulted in increased toxicity. Novel therapies are urgently required to improve PDAC patient survival. New treatments in other cancers such as melanoma, non-small-cell lung cancer, and renal cancer have emerged, based on immunotherapy targeting the immune checkpoints cytotoxic T-lymphocyte-associated antigen 4 or programmed death 1 ligand. However, the first clinical trials using such immune checkpoint inhibitors in PDAC have had limited success. Resistance to immunotherapy in PDAC remains unclear but could be due to tissue components (cancer-associated fibroblasts, desmoplasia, hypoxia) and to the imbalance between immunosuppressive and effector immune populations in the tumor microenvironment. In this review, we analyzed the presence of "good and bad immunological cops" in PDAC and discussed the significance of changes in their balance.

Combined use of two supervised learning algorithms to model sea turtle behaviours from tri-axial acceleration data.

Accelerometers are becoming ever more important sensors in animal-attached technology, providing data that allow determination of body posture and movement and thereby helping to elucidate behaviour in animals that are difficult to observe. We sought to validate the identification of sea turtle behaviours from accelerometer signals by deploying tags on the carapace of a juvenile loggerhead (Caretta caretta), an adult hawksbill (Eretmochelys imbricata) and an adult green turtle (Chelonia mydas) at Aquarium La Rochelle, France. We recorded tri-axial acceleration at 50 Hz for each species for a full day while two fixed cameras recorded their behaviours. We identified behaviours from the acceleration data using two different supervised learning algorithms, Random Forest and Classification And Regression Tree (CART), treating the data from the adult animals as separate from the juvenile data. We achieved a global accuracy of 81.30% for the adult hawksbill and green turtle CART model and 71.63% for the juvenile loggerhead, identifying 10 and 12 different behaviours, respectively. Equivalent figures were 86.96% for the adult hawksbill and green turtle Random Forest model and 79.49% for the juvenile loggerhead, for the same behaviours. The use of Random Forest combined with CART algorithms allowed us to understand the decision rules implicated in behaviour discrimination, and thus remove or group together some 'confused' or under--represented behaviours in order to get the most accurate models. This study is the first to validate accelerometer data to identify turtle behaviours and the approach can now be tested on other captive sea turtle species.

Two new species of gill parasites assigned to Protoancylodiscoides (Monogenea, Ancyrocephalidae) from Chrysichthys spp. (Siluriformes, Claroteidae) in River Sanaga (Cameroon).

Host specimens were sampled in the middle course of the River Sanaga (Cameroon) from January to October 2014. Two new species, Protoancylodiscoides auratum n. sp. from Chrysichthys auratus and Protoancylodiscoides combesi n. sp. from C. auratus, Chrysichthys nigrodigitatus and Chrysichthys longidorsalis, are herein described. These new helminths differ from the congeneric species by the size of the haptoral sclerites, the male copulatory organ length, the diameter and morphology of the vagina. At this stage, the present study suggests that Protoancylodiscoides auratum is oioxenous, while P. combesi is stenoxenous. The two new Protoancylodiscoides species bring to three the number of those parasitizing C. auratus, and to four the number of those described from Chrysichthys spp.

The angiotensin II type 2 receptor activates flow-mediated outward remodelling through T cells-dependent interleukin-17 production.

AIMS: The angiotensin II type 1 receptor (AT1R) through the activation of immune cells plays a key role in arterial inward remodelling and reduced blood flow in cardiovascular disorders. On the other side, flow (shear stress)-mediated outward remodelling (FMR), involved in collateral arteries growth in ischaemic diseases, allows revascularization. We hypothesized that the type 2 receptor (AT2R), described as opposing the effects of AT1R, could be involved in FMR. METHODS AND RESULTS: We studied FMR using a model of ligation of feed arteries supplying collateral pathways in the mouse mesenteric arterial bed in vivo. Seven days after ligation, diameter increased by 30% in high flow (HF) arteries compared with normal flow vessels. FMR was absent in mice lacking AT2R. At Day 2, T lymphocytes expressing AT2R were present preferentially around HF arteries. FMR did not occur in athymic (nude) mice lacking T cells and in mice treated with anti-CD3ε antibodies. AT2R activation induced interleukin-17 production by memory T cells. Treatment of nude mice or AT2R-deficient mice with interleukin-17 restored diameter enlargement in HF arteries. Interleukin-17 increased NO-dependent relaxation and matrix metalloproteinases activity, both important in FMR. Remodelling of feeding arteries in the skin flap model of ischaemia was also absent in AT2R-deficient mice and in anti-interleukin-17-treated mice. Finally, remodelling, absent in 12-month-old mice, was restored by a treatment with the AT2R non-peptidic agonist C21. CONCLUSION: AT2R-dependent interleukin-17 production by T lymphocyte is necessary for collateral artery growth and could represent a new therapeutic target in ischaemic disorders.

IL-34- and M-CSF-induced macrophages switch memory T cells into Th17 cells via membrane IL-1α.

Macrophages orchestrate the immune response via the polarization of CD4(+) T helper (Th) cells. Different subsets of macrophages with distinct phenotypes, and sometimes opposite functions, have been described. M-CSF and IL-34 induce the differentiation of monocytes into IL-10(high) IL-12(low) immunoregulatory macrophages, which are similar to tumor-associated macrophages (TAMs) in ovarian cancer. In this study, we evaluated the capacity of human macrophages induced in the presence of M-CSF (M-CSF macrophages) or IL-34 (IL-34 macrophages) and ovarian cancer TAMs to modulate the phenotype of human CD4(+) T cells. Taken together, our results show that M-CSF-, IL-34 macrophages, and TAMs switch non-Th17 committed memory CD4(+) T cells into conventional CCR4(+) CCR6(+) CD161(+) Th17 cells, expressing or not IFN-gamma. Contrary, the pro-inflammatory GM-CSF macrophages promote Th1 cells. The polarization of memory T cells into Th17 cells is mediated via membrane IL-1α (mIL-1α), which is constitutively expressed by M-CSF-, IL-34 macrophages, and TAMs. This study elucidates a new mechanism that allows macrophages to maintain locally restrained and smoldering inflammation, which is required in angiogenesis and metastasis.

IL-34 and macrophage colony-stimulating factor are overexpressed in hepatitis C virus fibrosis and induce profibrotic macrophages that promote collagen synthesis by hepatic stellate cells.

UNLABELLED: Chronic hepatitis C virus (HCV) infection is characterized by progressive hepatic fibrosis, a process dependent on monocyte recruitment and accumulation into the liver. The mediators expressed in chronically injured liver that control the differentiation of human monocytes into profibrotic macrophages (Mφ) remain poorly defined. We report that chronically HCV-infected patients with high fibrosis stages have higher serum levels of macrophage colony-stimulating factor (M-CSF) and interleukin (IL)-34 than HCV-infected patients with lower fibrosis stages and healthy subjects. Immunohistochemistry reveals an intense expression of IL-34 and M-CSF by hepatocytes around liver lesions. In addition, HCV infection and inflammatory cytokines enhance the in vitro production of IL-34 and M-CSF by hepatocytes. We next analyzed the acquisition of profibrotic properties by Mφ generated with M-CSF (M-CSF-Mφ) or IL-34 (IL-34-Mφ). M-CSF and IL-34 up-regulate the expression, by differentiating monocytes, of chemokine (C-C motif) ligand (CCL)2, CCL4, C-C chemokine receptor (CCR)1, and CCR5, which are involved in monocyte recruitment/Mφ accumulation in liver lesions. M-CSF-Mφ and IL-34-Mφ also express the hepatic stellate cell (HSC) activators, platelet-derived growth factor, transforming growth factor beta, and galectin-3. IL-34-Mφ and M-CSF-Mφ induce type I collagen synthesis by HSCs, the main collagen-producing cells in liver fibrosis. IL-13, whose expression correlates with the fibrosis stage in HCV-infected patients, decreases the expression of the collagenase, matrix metalloproteinase 1, by IL-34-Mφ and M-CSF-Mφ, thereby enhancing collagen synthesis. By inhibiting the production of interferon-gamma (IFN-γ) by activated natural killer cells, IL-34-Mφ and M-CSF-Mφ prevent the IFN-γ-induced killing of HSCs. CONCLUSION: These results identify M-CSF and IL-34 as potent profibrotic factors in HCV liver fibrosis.

IL-34 induces the differentiation of human monocytes into immunosuppressive macrophages. antagonistic effects of GM-CSF and IFNγ.

IL-34 is a recently identified cytokine that signals via the M-CSF receptor and promotes monocyte survival. Depending on the environment, monocytes can differentiate into macrophages (Mφ) or dendritic cells (DC). A wide spectrum of Mφ and DC subsets, with distinct phenotypes and functions, has been described. To date, the phenotype of monocytes exposed to IL-34 remains unexplored. We report here that IL-34 induces the differentiation of monocytes into CD14(high) CD163(high) CD1a(-) Mφ (IL-34-Mφ). Upon LPS stimulation, IL-34-Mφ exhibit an IL-10(high) IL-12(low) M2 profile and express low levels of the costimulatory molecules CD80 and CD86. IL-34-Mφ exhibit poor T cell costimulatory properties, and have potent immunosuppressive properties (decrease of TCR-stimulated T cell proliferation). For all the parameters analyzed, IL-34-Mφ are phenotypically and functionally similar to M-CSF-Mφ. IL-34 appears as efficient as M-CSF in inducing the generation of immunosuppressive Mφ. Moreover, the generation of IL-34-Mφ is mediated through the M-CSF receptor, is independent of endogenous M-CSF consumption and is potentiated by IL-6. In an attempt to identify strategies to prevent a deleterious M2 cell accumulation in some pathological situations, we observed that IFNγ and GM-CSF prevent the generation of immunosuppressive Mφ induced by IL-34. IFNγ also switches established IL-34-Mφ into immunostimulatory Mφ. In conclusion, we demonstrate that IL-34 drives the differentiation of monocytes into immunosuppressive M2, in a manner similar to M-CSF, and that IFNγ and GM-CSF prevent this effect.

Swallowing abnormalities in HIV infected children: an important cause of morbidity.

BACKGROUND: Swallowing disorders, well recognised in adults, contribute to HIV-infection morbidity. Little data however is available for HIV-infected children. The purpose of this study is to describe swallowing disorders in a group of HIV-infected children in Africa after the introduction of combined anti-retroviral therapy. METHODS: We describe 25 HIV-infected children referred for possible swallowing disorders. Clinical and videofluoroscopic assessment of swallowing (VFSS), HIV stage, and respiratory and neurological examination were recorded. RESULTS: Median age was 8 months (range 2.8-92) and 15 (60%) were male. Fifteen (60%) were referred for recurrent respiratory complaints, 4 (16%) for poor growth, 4 (16%) for poor feeding and 2 (8%) patients for respiratory complaints and either poor growth or feeding. Twenty patients (80%) had clinical evidence of swallowing abnormalities: 11 (44%) in the oral phase, 4 (16%) in the pharyngeal phase, and 5 (25%) in both the oral and pharyngeal phases. Thirteen patients had a videofluoroscopic assessment of which 6 (46%) where abnormal. Abnormalities were detected in the oral phase in 2, in the pharyngeal phase in 3, and in the oral and pharyngeal phase in 1; all of these patients also had evidence of respiratory involvement. Abnormal swallowing occurred in 85% of children with central nervous system disease. CNS disease was due to HIV encephalopathy (8) and miscellaneous central nervous system diseases (5). Three of 4 (75%) patients with thrush had an abnormal oral phase on assessment. No abnormalities of the oesophagus were found. CONCLUSIONS: This report highlights the importance of swallowing disorders in HIV infected children. Most patients have functional rather than structural or mucosal abnormalities. VFSS makes an important contribution to the diagnosis and management of these patients.

Gastro-Oesophageal Reflux in Infants and Children

Gastro-oesophageal reflux is a normal physiological phenomenon that is frequently associated with regurgitation in infants. In general; it resolves by the age of one year. Some children are more likely to have persistent symptoms and develop complications; e.g. children with congenital abnormalities of the oesophagus; neurological impairment; and a family history of gastro-oesophageal reflux disease (GORD). Preliminary evidence suggests that GORD in infancy and childhood may be a precursor to adult GORD. GORD is reflux that is associated with troublesome symptoms or complications. These complications are categorised into oesophageal and extra-oesophageal difficulties. Diagnosis in most patients relies on a thorough history and physical examination. However; the symptoms in infants and young children are often atypical. Patients with significant symptoms require more extensive diagnostic assessment; such as contrast radiography; oesophagoscopy and oesophageal pH-metry. In most cases; parental reassurance and advice on feeding are sufficient. Thickened feeds reduce the frequency of regurgitation. Patients with complications require potent acid inhibition and occasionally anti-reflux surgery