Multispecies probiotic protects gut barrier function in experimental models

AIM:To investigate the effect of the probiotic combination Lactibiane Tolerance?(LT)on epithelial barrier function in vitro and in vivo.METHODS:The effect of the multispecies probiotic LT was assessed on several models of epithelial barrier function both in vitro(in basal and inflammatory conditions)and in vivo[visceral hypersensitivity induced by chronic stress or by colonic perfusion of a fecal supernatant(FSN)from patients with irritable bowel syndrome(IBS)].In vitro,we measured the permeability of confluent T84 cell monolayers incubated with or without LT by evaluating the paracellular flux of macromolecules,in basal conditions and after stimulation with lipopolysaccharide(LPS)or with conditioned medium of colonic biopsies from IBS patients(IBS-CM).In vivo,male C57/Bl6 mice received orally NaCl or LT for 15 d and were submitted to water avoidance stress(WAS)before evaluating visceral sensitivity by measuring the myoelectrical activity of the abdominal muscle and the paracellular permeability with 51Cr-EDTA.Permeability and sensitivity were also measured after colonic instillation of FSN.Tight-junctions were assessed by immunoblotting and TLR-4 expression was evaluated by immunohistochemistry RESULTS:Incubation of T84 cell monolayers with LT in basal conditions had no significant effect on permeability(P>0.05 vs culture medium).By contrast,addition of LT bacterial bodies(LT)completely prevented the LPS-induced increase in paracellular permeability(P<0.01 vs LPS 10 ng/mL(LPS 10);P<0.01 vs LPS 100ng/mL(LPS 100),P>0.05 vs culture medium).The effect was dose dependent as addition of 109 LT bacterial bodies induced a stronger decrease in absorbance than 106 LT(109 LT+LPS 10:-20.1%±13.4,P<0.01vs LPS 10;106 LT+LPS 10:-11.6%±6.2,P<0.01 vs LPS 10;109 LT+LPS 100:-14.4%±5.5,P<0.01 vs LPS 100;106 LT+LPS 100:-11.6%±7.3,P<0.05 vs LPS 100).Moreover,the increase in paracellular permeability induced by culturing T84 cells with conditioned medium of colonic biopsies from IBS patients(IBS-CM)was completely inhibited in the presence of 109 LT(P<0.01 vs IBS-CM).LT also significantly prevented the epithelial disruption induced by intracolonic infusion of fecal supernatant from IBS patients(P<0.01 vs IBS FSN)or water avoidance stress P<0.01 vs WAS)in C57/Bl6 mice and increased the expression of occludin in vitro and in vivo,as assessed by immnunoblotting.The WAS-induced effect on visceral sensitivity was prevented by LT treatment since values obtained for all steps of colorectal distension were significantly(P<0.01)different from the WAS group.Finally,LT downregulated the response mediated through TLR-4 in vitro(decrease in tumor necrosis factorαsecretion in response to LPS:-65.8%for 109 LT and-52.5%for 106LT,P<0.01 vs LPS)and in vivo(inhibition of WAS induced an increase in TLR-4 expression in the LT treated mice colon,P<0.01 vs WAS).CONCLUSION:The probiotic LT mix prevented the disruption to the epithelial barrier induced by LPS,stress or colonic soluble factors from IBS patients and prevented visceral hypersensitivity.     

The anti-mitotic agents PTC-028 and PTC596 display potent activity in pre-clinical models of multiple myeloma but challenge the role of BMI-1 as an essential tumour gene

Future progress in the treatment of multiple myeloma (MM) requires both the characterisation of key drivers of the disease and novel, innovative approaches to tackle these vulnerabilities. The present study focussed on the pre-clinical evaluation of a novel drug class, BMI-1 modulators, in MM. We demonstrate potent activity of PTC-028 and PTC596 in a comprehensive set of in vitro and in vivo models, including models of drug resistance and stromal support. Treatment of MM cells with PTC-028 and PTC596 downregulated BMI-1 protein levels, which was found to correlate with drug activity. Surprisingly, BMI-1 was dispensable for the activity of BMI-1 modulators and MM cell growth. Our data rather point to mitotic arrest accompanied by myeloid cell leukaemia-1 (MCL-1) loss as key anti-MM mechanisms and reveal impaired MYC and AKT signalling activity due to BMI-1 modulator treatment. Moreover, we observed a complete eradication of MM after PTC596 treatment in the 5TGM.1 in vivo model and define epigenetic compounds and B cell leukaemia/lymphoma 2 homology domain 3 (BH3) mimetics as promising combination partners. These results bring into question the postulated role of BMI-1 as an essential MM gene and confirm BMI-1 modulators as potent anti-mitotic agents with encouraging pre-clinical activity that supports their rapid translation into clinical trials.     

B cell Biology: An Overview

As investigations into the innate immune responses that lead to allergic sensitization become better defined, there is a need to determine how allergens could interact with pattern recognition receptors that bind non-proteinaceous moieties. Many important allergens are not covalently bound to lipid or carbohydrate, but have structures belonging to lipid, glycan and glycolipid-binding families. These include ML-domain proteins, lipopolysaccharide-binding/cell permeability-increasing proteins, von Ebner gland lipocalins, salivary lipocalins/major urinary proteins, plant pathogenesis-related proteins PR-5 and -10, uteroglobins, non-specific lipid transfer proteins, large lipid transfer proteins and proteins with chitin and other carbohydrate-binding modules. The binding expected is overviewed with regard to importance of the allergens and their ability to elicit responses proposed from experimental models. The evidence compiled showing that allergens from the same source sensitize for different types of adaptive immune responses supports the concept that individual allergens within these sources have their own distinctive interactions with innate immunity.     

The management of postoperative reflux in congenital esophageal atresia–tracheoesophageal fistula: a systematic review

Purpose

Esophageal atresia (EA), with or without tracheoesophageal fistula (TEF), is associated with postoperative gastroesophageal reflux (GER). We performed a systematic review of the literature regarding routine anti-reflux medication post EA-TEF repair and its impact on postoperative GER and associated complications.

Methods

A comprehensive search was conducted using MEDLINE, EMBASE, CINHAL, CENTRAL (Cochrane library) electronic databases and gray literature. Full-text screening was performed in duplicate. Included articles reported a primary diagnosis of EA-TEF, a secondary diagnosis of postoperative GER, and primary treatment of GER with anti-reflux medications.

Results

Screening of 2,910 articles resulted in 25 articles (1,663 patients) for analysis. Most were single-center studies (92 %) and retrospective (76 %); there were no randomized control trials. Fifteen studies named the class of anti-reflux agent used, 3 the duration of therapy, and none either the dose prescribed or number of doses. Complications were inconsistently reported. Anti-reflux surgery was performed in 433/1,663 (26.0 %) patients. Average follow-up was 53.2 months (14 studies).

Conclusion

The quality of literature regarding anti-reflux medication for GER post EA-TEF repair is poor. There are no well-outlined algorithms for anti-reflux agents, doses, or duration of therapy. Standardized protocols and reliable reporting are necessary to develop guidelines to better manage postoperative GER in EA-TEF patients.