Macromolecule Translocation across the Intestinal Mucosa of HIV-Infected Patients by Transcytosis and through Apoptotic Leaks

Based on indirect evidence, increased mucosal translocation of gut-derived microbial macromolecules has been proposed as an important pathomechanism in HIV infection. Here, we quantified macromolecule translocation across intestinal mucosa from treatment-naive HIV-infected patients, HIV-infected patients treated by combination antiretroviral therapy, and HIV-negative controls and analyzed the translocation pathways involved. Macromolecule permeability was quantified by FITC-Dextran 4000 (FD4) and horseradish peroxidase (HRP) flux measurements. Translocation pathways were addressed using cold inhibition experiments. Tight junction proteins were characterized by immunoblotting. Epithelial apoptosis was quantified and translocation pathways were further characterized by flux studies in T84 cell monolayers using inducers and inhibitors of apoptosis and endocytosis. In duodenal mucosa of untreated but not treated HIV-infected patients, FD4 and HRP permeabilities were more than a 4-fold increase compared to the HIV-negative controls. Duodenal macromolecule permeability was partially temperature-dependent and associated with epithelial apoptosis without altered expression of the analyzed tight junction proteins. In T84 monolayers, apoptosis induction increased, and both apoptosis and endocytosis inhibitors reduced macromolecule permeability. Using quantitative analysis, we demonstrate the increased macromolecule permeability of the intestinal mucosa in untreated HIV-infected patients. Combining structural and mechanistic studies, we identified two pathways of increased macromolecule translocation in HIV infection: transcytosis and passage through apoptotic leaks

Inflammatory bowel disease (IBD)-like disease in a case of a 33-year old man with glycogenosis 1b

Background Inflammatory bowel disease (IBD)-like conditions in glycogen storage disease (GSD) type Ib have been predominantly described in children. Signs and symptoms of GSD type Ib are hypoglycemia, pancytopenia and hepatosplenomegaly. Based on few published cases, there is evidence that granulocyte-colony stimulating factor (G-CSF) in patients with glycogenosis–related pancytopenia might ameliorate the IBD-like disease through leukocyte increase. Case presentation Here we firstly describe a case of an adult 33-year-old Caucasian male patient with GSD type Ib accompanied with IBD-like disease with persistent pancytopenia despite moderate-dose G-CSF treatment. Recent vomiting and abdominal discomfort were due to a high-grade stenosis in the transverse colon. A dose increase of the G-CSF successfully normalized his leukocyte count. However, the stenosis worsened and surgical therapy was needed. Conclusion We suggest that symptomatic patients with GSD type Ib should undergo endoscopic examination in order to detect IBD-like disease and to initiate early treatment

PuraStat in gastrointestinal bleeding: results of a prospective multicentre observational pilot study

Background: A recently developed haemostatic peptide gel for endoscopic application has been introduced to improve the management of gastrointestinal bleeding. The aim of this pilot study was to evaluate the feasibility, safety, efficacy and indication profiles of PuraStat in a clinical setting. Methods: In this prospective observational multicentre pilot study, patients with acute non-variceal gastrointestinal bleeding (upper and lower) were included. Primary and secondary application of PuraStat was evaluated. Haemoglobin, prothrombin time, platelets and transfusion behaviour were documented before and after haemostasis. The efficacy of PuraStat was assessed during the procedure, at 3 days and 1 week after application. Results: 111 patients with acute gastrointestinal bleeding were recruited into the study. 70 percent (78/111) of the patients had upper gastrointestinal bleeding and 30% (33/111) had lower gastrointestinal bleeding. After primary application of PuraStat, initial haemostatic success was achieved in 94% of patients (74/79, 95% CI 88-99%), and in 75% of the patients when used as a secondary haemostatic product, following failure of established techniques (24/32, 95% CI 59-91%). The therapeutic success rates (absence of rebleeding) after 3 and 7 days were 91% and 87% after primary use, and 87% and 81% in all study patients. Overall rebleeding rate at 30 day follow-up was 16% (18/111). In the 5 patients who finally required surgery (4.5%), PuraStat allowed temporary haemostasis and stabilisation. Conclusions: PuraStat expanded the therapeutic toolbox available for an effective treatment of gastrointestinal bleeding sources. It could be safely applied and administered without complications as a primary or secondary therapy. PuraStat may additionally serve as a bridge to surgery in order to achieve temporary haemostasis in case of refractory severe bleeding, possibly playing a role in preventing immediate emergency surgery

Oral and Fecal Campylobacter concisus Strains Perturb Barrier Function by Apoptosis Induction in HT-29/B6 Intestinal Epithelial Cells

Campylobacter concisus infections of the gastrointestinal tract can be accompanied by diarrhea and inflammation, whereas colonization of the human oral cavity might have a commensal nature. We focus on the pathophysiology of C. concisus and the effects of different clinical oral and fecal C. concisus strains on human HT-29/B6 colon cells. Six oral and eight fecal strains of C. concisus were isolated. Mucus-producing HT-29/B6 epithelial monolayers were infected with the C. concisus strains. Transepithelial electrical resistance (Rt) and tracer fluxes of different molecule size were measured in Ussing chambers. Tight junction (TJ) protein expression was determined by Western blotting, and subcellular TJ distribution was analyzed by confocal laser-scanning microscopy. Apoptosis induction was examined by TUNEL-staining and Western blot of caspase-3 activation. All strains invaded confluent HT-29/B6 cells and impaired epithelial barrier function, characterized by a time- and dose-dependent decrease in Rt either after infection from the apical side but even more from the basolateral compartment. TJ protein expression changes were sparse, only in apoptotic areas of infected monolayers TJ proteins were redistributed. Solely the barrier-forming TJ protein claudin-5 showed a reduced expression level to 66±8% (P<0.05), by expression regulation from the gene. Concomitantly, Lactate dehydrogenase release was elevated to 3.1±0.3% versus 0.7±0.1% in control (P<0.001), suggesting cytotoxic effects. Furthermore, oral and fecal C. concisus strains elevated apoptotic events to 5-fold. C. concisus-infected monolayers revealed an increased permeability for 332 Da fluorescein (1.74±0.13 vs. 0.56±0.17 10−6 cm/s in control, P<0.05) but showed no difference in permeability for 4 kDa FITC-dextran (FD-4). The same was true in camptothecin-exposed monolayers, where camptothecin was used for apoptosis induction

Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a $Z$ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 $< p_{\textrm{T}} < 100$ GeV and in the pseudorapidity range $2.5 < \eta < 4$. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb$^{-1}$. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

Impact of local and systemic mucosal infections on barrier function and immune system of the intestinal mucosa

Aufgrund einer stetigen Exposition gegenüber einer großen Zahl von potentiell pathogenen Keimen ist die intestinale Mukosa ein häufiger Manifestationsort von Infektionen. Dabei können die primären molekularen Zielstrukturen einer Infektion direkt im Epithel oder in tieferen Schichten der Mukosa, wie etwa dem Mukosa-assoziierten Immunsystem lokalisiert sein sein. Unabhängig vom primären Ansatzpunkt kommt es aufgrund der engen Verzahnung der mukosalen Funktionen in der Folge mukosaler Infektionen meist zu Störungen der epithelialen Transport- und Barrierefunktionen. In der vorliegenden Arbeit wird anhand von Untersuchungen zu exemplarischen Infektionen ein Beitrag zu einem vertieften Verständnis der Mechanismen mukosaler Infektionen geleistet. Methodisch erfolgten die Untersuchungen auf zwei Ebenen. Studien zu epithelialen Mechanismen wurden am isolierten Modellepithel (HT-29/B6) durchgeführt. Das HT-29/B6-Modell zeigte sich als geeignet, sowohl Perturbationen der Chlorid- und Muzinsekretion als auch solche der parazellulären Leitfähigkeit - somit die wichtigsten Erreger-bedingten Diarrhoemechanismen - quantitativ abzubilden. Mit diesem Modell wurden u.a. der Mechanismus der durch Choleratoxin ausgelösten intestinalen Muzinsekretion, der Diarrhoe-Mechanismus bei der Aeromonas-Infektion und Translokationsmechanismen von extraintestinal pathogenen Escherichia coli analysiert. Untersuchungen zu den mukosalen Auswirkungen der HIV-Infektion erfolgten dagegen ex vivo an endoskopisch gewonnener nativer Dünndarmmukosa. Da das HI Virus zwar Zellen des mukosalen Immunsystems, nicht aber Enterozyten infiziert, sind diese Untersuchungen eine komplementäre Ergänzung zum vorgenannten Epithel-fokussierten Ansatz. Darüber hinaus wird derzeit angenommen, dass Störungen der mukosalen Barrierefunktion eine zentrale Bedeutung für den charakteristischen progressiven Immundefekt der HIV- Infektion besitzen. In den Untersuchungen zeigte sich, dass bereits in der Frühphase der akuten HIV-Infektion ein Barrieredefekt der Dünndarmmukosa ausgebildet wird, der bei der unbehandelten chronischen Infektion fortbesteht, aber durch eine suppressive virostatische Therapie zur Rückbildung gebracht werden kann. Als strukturelle Korrelate der Barrierestörung wurden eine erhöhte epitheliale Apoptoserate und eine veränderte Expression von Schlussleistenproteinen identifiziert. Als zentraler Mechanismus des Barrieredefekts zeigte sich eine - vermutlich durch erhöhten Antigen-Übertritt unterhaltene - mukosale Immunaktivierung. Bei unbehandelten chronisch Infizierten fand sich ferner eine dramatische Zunahme regulatorischer T Zellen in der Darmmukosa, die als ein der fortgesetzten mukosalen Immunaktivierung entgegenwirkender Mechanismus interpretiert werden kann.As a consequence of its continual exposure to a vast array of luminal germs and antigens, the intestinal mucosa is a site of frequent infections. The primary muloecular targets of mucosal infections may be located within the epithelium or within subepithelial structures such as components of the mucosa associateed immune system. Independently from the primary mucosal target, impairment of epithelial transport and barrier functions are common consequences of mucosal infections. In this work, we present studies on distinctive mucosal infections. Employing a highly differentiated model colon epithelium (HT-29/B6), we established an experimental model suited for analysis of diarrheal mechanisms in enteral infections. By use of this model, we analysed the mechanisms of cholera toxin induced intestinal mucin secretion, the diarrheal mechanism of aeromonas enteritis and the translocation of extraintestinal pathogenic Escherichia coli. In a second set of studies we used duodenal mucosa obtained by endocopic biopsies to investigate the barrier effects of HIV infection. HIV does not productively infect epithelial cells, whereas mucosal T lymphocytes located in subepithelial layers are regarded as primary cellular targets of HIV. Therefore these studies were complementary to the aformentioned epithelium- focussed investigations with the HT-29/B6 model. Our results demonstrate that a mucosal barrier-defect is evident already during early acute infection. It is secondary to mucosal immune activation and can be reversed by suppressive antiretroviral therapy. Structurally the HIV-induced barrier defect is owing to increased epithelial apoptoses and altered protein composition of the epithelial tight junctions. In untreated chronically HIV-infected patients mucosal regulatory T cells are strongly increased, a finding which may be interpretesd as a counterregulatory mechanism to the HIV-induced mucosal immune activation

Molekulare Diagnostik der infektiösen Gastroenteritis

&lt;jats:title&gt;Zusammenfassung&lt;/jats:title&gt;&lt;jats:p&gt;Die infektiöse Gastroenteritis gehört zu den häufigsten Erkrankungen überhaupt. Leitsymptom ist die akute Diarrhö mit oder ohne Erbrechen. Aufgrund des selbstlimitierenden Charakters der Erkrankung ist die Therapie in erster Linie symptomatisch und unabhängig vom auslösenden Pathogen. Eine Erregerdiagnostik ist nur sinnvoll, wenn deren Ergebnis erwartungsgemäß eine Änderung der Therapie oder des Hygienemanagements nach sich zieht. Die konventionelle Stuhldiagnostik beruht auf kulturellen, immunologischen und mikroskopischen Nachweisverfahren. Sie wurde in den letzten Jahren durch molekulare Verfahren erweitert. Insbesondere wurden von verschiedenen Herstellern so genannte integrierte Gastroenteritispanel auf den Markt gebracht, bei denen mittels Multiplexpolymerasekettenreaktion eine einzige Stuhlprobe simultan auf eine Vielzahl bakterieller, viraler und protozoaler Erreger untersucht werden kann. In diesem Beitrag wird anhand von klinischen Studien der Stellenwert dieser Verfahren im Vergleich zu den konventionellen Methoden der Stuhldiagnostik diskutiert. Zusammenfassend zeigen die molekularen Gastroenteritispanels bei deutlich kürzerer Prozessierungszeit signifikant höhere Detektionsraten. Ob aber die verbesserten Detektionsraten zu einer Verbesserung von Therapie oder Hygienemanagement führen, ist noch fraglich, sodass ihr Einsatz derzeit nur in speziellen Situationen als Zusatzmethode zur konventionellen Diagnostik empfohlen wird.&lt;/jats:p&gt