Intestinal permeation enhancers (PEs) are key components in »12 oral peptide formulations in clinical trials for a range of molecules, primarily insulin and glucagon-like-peptide 1 (GLP-1) analogs. The main PEs comprise medium chain fatty acid-based systems (sodium caprate, sodium caprylate, and N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC)), bile salts, acyl carnitines, and EDTA. Their mechanism of action is complex with subtle differences between the different molecules. With the exception of SNAC and EDTA, most PEs fluidize the plasma membrane causing plasma membrane perturbation, as well as enzymatic and intracellular mediator changes that lead to alteration of intestinal epithelial tight junction protein expression. The question arises as to whether PEs can cause irreversible epithelial damage and tight junction openings sufficient to permit co-absorption of payloads with bystander pathogens, lipopolysaccharides and its fragment, or exo-and endotoxins that may be associated with sepsis, inflammation and autoimmune conditions. Most PEs seem to cause membrane perturbation to varying extents that is rapidly reversible, and overall evidence of pathogen co-absorption is generally lacking. It is unknown however, whether the intestinal epithelial damage-repair cycle is sustained during repeat-dosing regimens for chronic therapy.

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Publication information Peptides, 71 : 1-7Publisher Elsevier Item record/more information http://hdl.handle.net/10197/8723 Publisher's statementThis is the author's version of a work that was accepted for publication in Peptides. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Peptides (VOL 71, ISSUE 2015, (2015 colonic mucosae were low, but were significantly increased in each tissue type by the medium chain fatty acids (MCFA) permeation enhancers, sodium caprate (C 10 ) and the sodium salt of 10-undecylenic acid (uC 11 ). IPP and LKP were therefore stable against intestinal and liver peptidases and were non-cytotoxic; their P app values across rat intestinal mucosae were low, but could be increased by MCFA. There is potential to make on oral dosage form once in vivo pharmacology is confirmed.

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Publication informationEuropean Journal of Pharmaceutics and Biopharmaceutics, Publisher ElsevierItem record/more information http://hdl.handle.net/10197/8514 an apical buffer pH of 7.4. Gly-Sar reduced the P app across isolated jejunal mucosae and the 32 area under the curve (AUC) in intra-jejunal instillations when the apical/luminal buffer pH 33 was either 7.4 or 6.5. However, the jejunal surface acidic pH was maintained in rat jejunal 34 tissue even when the apical side buffer pH was 7.4 due to the presence of the microclimate 35 which is not present in monolayers. PepT1 expression was confirmed by 36 immunofluorescence on monolayers and brush border of rat jejunal tissue. This data suggest 37 that IPP and LKP are highly permeable and cross small intestinal epithelia in part by the 38 PepT1 transporter, with an additional contribution from the paracellular route. 39 40 41 Publisher's statement þÿ T h i s i s t h e a u t h o r s v e r s i o n o f a w o r k t h a t w a s a c c e p t e d f o r p u b l i c a t i o n i n E u r o p e a n

Publication information Trends in Food Science and Technology, 53 : 90-101Publisher Elsevier Item record/more information

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In inflammatory bowel disease (IBD), the intestinal epithelium is characterized by increased permeability both in active disease and remission states. The genetic underpinnings of this increased intestinal permeability are largely unstudied, in part due to a lack of appropriate modelling systems. Our aim is to develop an in vitro model of intestinal permeability using induced pluripotent stem cell (iPSC)-derived human intestinal organoids (HIOs) and human colonic organoids (HCOs) to study barrier dysfunction. iPSCs were generated from healthy controls, adult onset IBD, and very early onset IBD (VEO-IBD) patients and differentiated into HIOs and HCOs. EpCAM+ selected cells were seeded onto Transwell inserts and barrier integrity studies were carried out in the presence or absence of pro-inflammatory cytokines TNFα and IFNγ. Quantitative real-time PCR (qRT-PCR), transmission electron microscopy (TEM), and immunofluorescence were used to determine altered tight and adherens junction protein expression or localization. Differentiation to HCO indicated an increased gene expression of CDX2, CD147, and CA2, and increased basal transepithelial electrical resistance compared to HIO. Permeability studies were carried out in HIO- and HCO-derived epithelium, and permeability of FD4 was significantly increased when exposed to TNFα and IFNγ. TEM and immunofluorescence imaging indicated a mislocalization of E-cadherin and ZO-1 in TNFα and IFNγ challenged organoids with a corresponding decrease in mRNA expression. Comparisons between HIO- and HCO-epithelium show a difference in gene expression, electrophysiology, and morphology: both are responsive to TNFα and IFNγ stimulation resulting in enhanced permeability, and changes in tight and adherens junction architecture. This data indicate that iPSC-derived HIOs and HCOs constitute an appropriate physiologically responsive model to study barrier dysfunction and the role of the epithelium in IBD and VEO-IBD.