Cytotoxic CD8+ T cells are essential for the control of viral liver infections, such as those caused by HBV or HCV. It is not entirely clear whether CD4+ T-cell help is necessary for establishing anti-viral CD8+ T cell responses that successfully control liver infection. To address the role of CD4+ T cells in acute viral hepatitis, we infected mice with Lymphocytic Choriomeningitis Virus (LCMV) of the strain WE; LCMV-WE causes acute hepatitis in mice and is cleared from the liver by CD8+ T cells within about two weeks. The role of CD4+ T-cell help was studied in CD4+ T cell-lymphopenic mice, which were either induced by genetic deficiency of the major histocompatibility (MHC) class II transactivator (CIITA) in CIITA−/− mice, or by antibody-mediated CD4+ cell depletion. We found that CD4+ T cell-lymphopenic mice developed protracted viral liver infection, which seemed to be a consequence of reduced virus-specific CD8+ T-cell numbers in the liver. Moreover, the anti-viral effector functions of the liver-infiltrating CD8+ T cells in response to stimulation with LCMV peptide, notably the IFN-γ production and degranulation capacity were impaired in CIITA−/− mice. The impaired CD8+ T-cell function in CIITA−/− mice was not associated with increased expression of the exhaustion marker PD-1. Our findings indicate that CD4+ T-cell help is required to establish an effective antiviral CD8+ T-cell response in the liver during acute viral infection. Insufficient virus control and protracted viral hepatitis may be consequences of impaired initial CD4+ T-cell help.

TREM1 (Triggering Receptor Expressed on Myeloid Cells 1) is a pro-inflammatory receptor expressed by phagocytes, which can also be released as a soluble molecule (sTREM1). The roles of TREM1 and sTREM1 in liver infection and inflammation are not clear. Here we show that patients with hepatitis B virus (HBV) or hepatitis C virus (HCV) infection manifest elevated serum levels of sTREM1. In mice, experimental viral hepatitis induced by infection with Lymphocytic Choriomeningitis Virus (LCMV)-WE was likewise associated with increased sTREM1 in serum and urine, and with increased TREM1 and its associated adapter molecule DAP12 in the liver. Trem1−/− mice showed accelerated clearance of LCMV-WE and manifested attenuated liver inflammation and injury. TREM1 expression in the liver of wild-type mice was mostly confined to infiltrating neutrophils, which responded to LCMV by secretion of CCL2 and TNF-α, and release of sTREM1. Accordingly, the production of CCL2 and TNF-α was decreased in the livers of LCMV-infected Trem1−/− mice, as compared to LCMV-infected wildtype mice. These findings indicate that TREM1 plays a role in viral hepatitis, in which it seems to aggravate the immunopathology associated with viral clearance, mainly by increasing the inflammatory activity of neutrophils.

Background: Infants with ileostomies often suffer from sodium depletion, ultimately leading to a failure to thrive. Moreover, early-infantile microbial dysbiosis may potentially aggravate weight faltering. Given that sodium supplementation has been used to restore weight gain and feeding practices largely determine infantile microbiota, the current study investigated the effect of sodium chloride (NaCl) on weight gain and intestinal microbiome in infants with jejuno-and ileostomies. Methods: A prospective cohort study including 24 neonates with enterostomies compared 19 subjects receiving oral NaCl (5.85%) to five subjects without supplementation with respect to postoperative changes in thrive and the intestinal microbiome. Results: Infants receiving NaCl after enterostomy-surgery showed vastly improved weight gain and an increased abundance of Lactobacillus in fecal samples, as compared to subjects without oral supplement who displayed decreasing percentiles for weight and did not reveal a higher abundance of probiotic strains within the ostomy effluent. Contrarily, Klebsiella was equally enriched in supplemented infants, reflecting a higher susceptibility for infections in preterm neonates. Discussion: Our findings support oral NaCl supplementation as a mainstay of postoperative treatment in infants with small bowel ostomies who are predisposed to suffer from a sodium depletion-associated failure to thrive. Not only does NaCl promote weight gain by increasing glucose resorption, but it also appears to induce microbial restoration by enhancing the abundance of health-promoting probiotic bacteria. This finding has an even greater significance when facing an elevated Klebsiella/Bifidobacteria (K/B) ratio, believed to represent an early-life microbial biomarker for development of allergic disease.

Aim Several motor learning models have been used to teach highly complex procedural skills in medical education. The aim of this randomized controlled trial was to assess the efficiency of telementoring of open and laparoscopic suturing of medical students compared to conventional in-person teaching and training. Methods After randomization, 23 medical students were assigned to either the telementoring or the in-person training group. Both groups were taught by surgically trained residence with a student–teacher ratio of 1:1 (teacher–student). Open suturing was assessed in a model of congenital diaphragmatic hernia and laparoscopic suturing in a model of bowel anastomosis. All subjects were trained according to the spaced learning concept for 3 hours. Primary end points were time, knot quality, precision, knot strength, and overall knotting performance/competency. Furthermore, we utilized the Surgery Task Load Index to evaluate the cognitive load of both teaching techniques. Students' subjective progress regarding skill acquisitions and acceptance of telementoring was assessed using a nine-item questionnaire. Results All 23 trainees significantly improved after training in all knot attributes. More than 90% of all subjects reached proficiency in both groups. In-person training and telementoring were similarly practical, and no significant differences regarding speed, knot quality, precision, knot stability, and procedure performance/competency were found. Students perceived no difference in acquisition of factual or applicational knowledge between the two groups. General acceptance of telementoring was moderate in both groups before training, but increased during training in students actually assigned to this group, in comparison to students assigned to conventional teaching. Conclusion The current study shows that telementoring of open and laparoscopic suturing is an ideal answer to the current coronavirus disease 2019 pandemic, ensuring continuous training. On-site training and telementoring are similarly effective, leading to substantial improvement in proficiency in intracorporeal suturing and knot tying. Likewise, students' subjective progress regarding skill acquisitions and cognitive load does not differ between teaching methods. Skepticism toward telementoring decreases after exposure to this learning method. Given our results, telementoring should be considered a highly effective and resource-saving educational approach even after the current pandemic.