Opsonized streptococcal cell walls cross-link human leukocytes and erythrocytes by complement receptors.

Serum-opsonized group A streptococcal cell walls, consisting of peptidoglycan-polysaccharide polymers (PG-APS), induced monolayers of human neutrophils, monocytes, and eosinophils to aggregate. When erythrocytes were present in the incubation medium, they also were associated with the leukocyte aggregates. By immunofluorescence staining, PG-APS was localized at the site of cell-to-cell contact. By scanning electron microscopy the cells appeared to adhere to one another by surface contact; filopodia often acted as connectors, particularly in leukocyte-erythrocyte interaction. Cellular binding of PG-APS and aggregation were dependent upon C3 fixation. No aggregation was observed when heat-inactivated serum was used as an opsonin. In contrast to peptidoglycan, an activator of the alternative complement pathway, the group-specific polysaccharide moiety of PG-APS induced no cellular aggregation. Rosette formation was observed in suspensions when neutrophils were incubated with erythrocytes coated with C3b-opsonized PG-APS. Cell monolayers bound serum-opsonized PG-APS, but aggregation was observed only when serum was present in the incubation medium. Similar results were obtained with C5-deficient serum. No aggregation was observed with heat-inactivated serum or bovine serum albumin. A heat-labile serum component(s) appears to be required to elicit leukocyte aggregation. It is suggested that C3 fixed to PG-APS acts as a bridge to link cells together in clusters as a result of common recognition of C3 by leukocyte and erythrocyte complement receptors

DOP086 Intestinal resection in Crohn's disease is associated with significant and durable improvement in health related quality of life although to a lesser extent in women and smokers. Results from the POCER study

Background: Health-related QoL (HRQoL) measures perceptions, illness experience, and functional status. Crohn’s disease patients have lower HRQoL, poorer function and more emotional distress than healthy individuals, even when in remission. HRQoL improves with medically or surgically induced remission. We evaluated the effects of surgery on HRQoL. Methods: Mucosal healing was the target in the Post-Operative Crohn’s Endoscopic Recurrence (POCER) treat-to-target study. Drug treatments included metronidazole, and thiopurine or adalimumab for high risk patients (smoker, perforating disease, 2nd operation). Patients were randomised to colonoscopy at 6 months with intensified treatment for endoscopic recurrence (“active care”) or no colonoscopy (“standard care”). All patients were colonoscoped at 18 months. HRQoL was assessed with a general (SF36) and disease-specific (IBDQ) questionnaire pre-operatively and at 6, 12 and 18 months. CRP, CDAI and faecal calprotectin (FC) were measured longitudinally. Results: 174 patients (median age 38, 55% female) were included. HRQoL was poor pre-operatively: median SF36 = 40 (where maximum = 100, Australian normal = 70 90) and IBDQ = 120 (maximum = 224, average score in Australian Crohn’s disease patients=156). For all patients both SF36 and IBDQ improved significantly at 6 months to 78 and 178 respectively, and this was sustained at 12 months (81 and 183) and 18 months (80 and 182 respectively). Females had lower HRQoL than males post-op at 6 (SF36 p = 0.012; IBDQ p = 0.007) and 12 months (SF36 p = 0.001, IBDQ p = 0.006). Smokers had poorer HRQoL compared to non-smokers at both 12 and 18 months: SF36 at 12 month p = 0.002, and IBDQ at 12 and 18 months (p = 0.046, p = 0.047 respectively). Persistent endoscopic remission, thiopurine or adalimumab therapy and treatment step up were not associated with changes in HRQoL. There was a significant inverse correlation between CDAI and both SF-36 and IBDQ at 6, 12 and 18 months. HRQoL did not correlate with endoscopic remission, CRP or FC. Conclusions: Intestinal resection of all macroscopic Crohn’s disease, with a focus on maintaining remission, is associated with significant and sustained improvement in general and disease-specific HRQoL. The lower HRQoL in female patients and smokers may reflect partly their lower QoL in the healthy and IBD populations, but this requires further investigation. A higher clinical disease activity index, but not direct measures of active disease or type of drug therapy, is associated with a lower HRQoL, suggesting that symptoms reflect subjective personal factors and not active mucosal disease or drug effects.E.K. Wright ... J.M. Andrews ... P.A. Bampton ... et al

Organoid cultures recapitulate esophageal adenocarcinoma heterogeneity providing a model for clonality studies and precision therapeutics

Esophageal adenocarcinoma (EAC) incidence is increasing while 5-year survival rates remain less than 15%. A lack of experimental models has hampered progress. We have generated clinically annotated EAC organoid cultures that recapitulate the morphology, genomic, and transcriptomic landscape of the primary tumor including point mutations, copy number alterations, and mutational signatures. Karyotyping of organoid cultures has confirmed polyclonality reflecting the clonal architecture of the primary tumor. Furthermore, subclones underwent clonal selection associated with driver gene status. Medium throughput drug sensitivity testing demonstrates the potential of targeting receptor tyrosine kinases and downstream mediators. EAC organoid cultures provide a pre-clinical tool for studies of clonal evolution and precision therapeutics

The Na+-K+-2Cl- cotransporter and the osmotic stress response in a model salt transport epithelium.

Epithelia are physiologically exposed to osmotic stress resulting in alteration of cell volume in several aspects of their functioning; therefore, the activation of ‘emergency’ systems of rapid cell volume regulation is fundamental in their physiology. In this review, the physiological response to osmotic stress, particularly hypertonic stress, was described in a salt-transporting epithelium, the intestine of the euryhaline teleost European eel. This epithelium is physiologically exposed to changes in extracellular osmolarity and represents a good physiological model for functional studies on cellular volume regulation, permitting the study of volume regulated ion transport mechanisms in a native tissue. An absorptive form of the cotransporter, homologue of the renal NKCC2, localized on the apical membrane, was found in the intestine of the euryhaline teleost European eel. This cotransporter accounts for the luminal uptake of Cl); it operates in series with a basolateral Cl) conductance and presumably a basolateral electroneutral KCl cotransport and in parallel with a luminal K+ conductance. The ion transport model described for eel intestine, based on the operation of an absorptive luminal Na+–K+– 2Cl), is basically the same as the model that has been proposed for the thick ascending limb (cTAL) of the mammalian renal cortex. This paper focuses on the role of Na+–K+–2Cl) cotransport in the responses to hypertonic stress in the eel intestine and the role of cytoskeleton (either actin-based or tubulin based) is discussed