Investigating the Impact of Crohn's Disease on the Bioaccessibility of a Lipid-Based Formulation with an In Vitro Dynamic Gastrointestinal Model.

The aim of the study was to investigate the impact of Crohn's disease (CD) on the performance of a lipid-based formulation of ciprofloxacin in a complex gastrointestinal simulator (TIM-1, TNO) and to compare the luminal environment in terms of bile salt and lipid composition in CD and healthy conditions. CD conditions were simulated in the TIM-1 system with a reduced concentration of porcine pancreatin and porcine bile. The bioaccessibility of ciprofloxacin was similar in simulated CD and healthy conditions considering its extent as well as its time course in the jejunum and ileum filtrate. Differences were observed in terms of the luminal concentration of triglycerides, monoglycerides, and fatty acids in the different TIM-1 compartments, indicating a reduction and delay in the lipolysis of formulation excipients in CD. The quantitative analysis of bile salts revealed higher concentrations for healthy conditions (standard TIM-1 fasted-state protocol) in the duodenum and jejunum TIM-1 compartments compared to published data in human intestinal fluids of healthy subjects. The reduced concentrations of bile salts in simulated CD conditions correspond to the levels observed in human intestinal fluids of healthy subjects in the fasted state.A lipidomics approach with ultra performance liquid chromatography (UPLC)/mass spectrometry (MS) has proven to be a time-efficient method to semiquantitatively analyze differences in fatty acid and bile salt levels between healthy and CD conditions. The dynamic luminal environment in CD and healthy conditions after administration of a lipid-based formulation can be simulated using the TIM-1 system. For ciprofloxacin, an altered luminal lipid composition had no impact on its performance indicating a low risk of altered performance in CD patients.

The expression and localization of V-ATPase and cytokeratin 5 during postnatal development of the pig epididymis.

OBJECTIVE: We examined the localization and expression of H+ pumping vacuolar ATPase (V-ATPase) and cytokeratin 5 (KRT5) in the epididymis of pigs, expressed in clear and basal cells, respectively, during postnatal development. METHODS: Epididymides were obtained from pigs at 1, 7, 21, 60, 120, and 180 days of age; we observed the localization and expression patterns of V-ATPase and KRT5 in the different regions of these organs, namely, the caput, corpus, and cauda. The differentiation of epididymal epithelial cells was determined by immunofluorescence labeling using cell-type-specific markers and observed using confocal microscopy. RESULTS: At postnatal day 5 (PND5), the localization of clear cells commenced migration from the cauda toward the caput. Although at PND120, goblet-shaped clear cells were detected along the entire length of the epididymis, those labeled for V-ATPase had disappeared from the corpus to cauda and were maintained only in the caput epididymis in adult pigs. In contrast, whereas basal cells labeled for KRT5 were only present in the vas deferens at birth, they were detected in all regions of the epididymis at PND60. These cells were localized at the base of the epithelium; however, no basal cells characterized by luminally extending cell projections were observed in any of the adult epididymides examined. CONCLUSION: The differentiation of clear and basal cells progressively initiates in a retrograde manner from the cauda to the caput epididymis. The cell-type-specific distribution and localization of the epithelial cells play important roles in establishing a unique luminal environment for sperm maturation and storage in the pig epididymis.

Mucosal healing progression after acute colitis in mice.

BACKGROUND: Mucosal healing has become a therapeutic goal to achieve stable remission in patients with inflammatory bowel diseases. To achieve this objective, overlapping actions of complex cellular processes, such as migration, proliferation, and differentiation, are required. These events are longitudinally and tightly controlled by numerous factors including a wide range of distinct regulatory proteins. However, the sequence of events associated with colon mucosal repair after colitis and the evolution of the luminal content characteristics during this process have been little studied. AIM: To document the evolution of colon mucosal characteristics during mucosal healing using a mouse model with chemically-induced colitis. METHODS: C57BL/6 male mice were given 3.5% dextran sodium sulfate (DSS) in drinking water for 5 d. They were euthanized 2 (day 7), 5 (day 10), 8 (day 13), and 23 (day 28) d after DSS removal. The colonic luminal environment and epithelial repair processes during the inflammatory flare and colitis resolution were analyzed with reference to a non-DSS treated control group, euthanized at day 0. Epithelial repair events were assessed histo-morphologically in combination with functional permeability tests, expression of key inflammatory and repairing factors, and evaluation of colon mucosa-adherent microbiota composition by 16S rRNA sequencing. RESULTS: The maximal intensity of colitis was concomitant with maximal alterations of intestinal barrier function and histological damage associated with goblet cell depletion in colon mucosa. It was recorded 2 d after termination of the DSS-treatment, followed by a progressive return to values similar to those of control mice. Although signs of colitis were severe (inflammatory cell infiltrate, crypt disarray, increased permeability) and associated with colonic luminal alterations (hyperosmolarity, dysbiosis, decrease in short-chain fatty acid content), epithelial healing processes were launched early during the inflammatory flare with increased gene expression of certain key epithelial repair modulators, including transforming growth factor-ß, interleukin (Il)-15, Il-22, Il-33, and serum amyloid A. Whereas signs of inflammation progressively diminished, luminal colonic environment alterations and microscopic abnormalities of colon mucosa persisted long after colitis induction. CONCLUSION: This study shows that colon repair can be initiated in the context of inflamed mucosa associated with alterations of the luminal environment and highlights the longitudinal involvement of key modulators.

Impact of regional differences along the gastrointestinal tract of healthy adults on oral drug absorption: An UNGAP review.

Oral administration is the most common route of drug delivery. The absorption of a drug from the gut into the bloodstream involves disintegration of the solid dosage form, dissolution of the active pharmaceutical ingredient and its transport across the gut wall. The efficiency of these processes is determined by highly complex and dynamic interplay between the gastrointestinal tract, the dosage form and the API. The European Network on Understanding Gastrointestinal Absorption-related Processes (UNGAP) aims to improve our understanding of intestinal drug absorption by creating a multidisciplinary Network of researchers from academia and industry engaging in scientific discussions. As part of the basis for the UNGAP project, this review aims to summarize the current knowledge on anatomy and physiology of the human gastrointestinal tract with emphasis on human studies for the evaluation of the regional drug absorption and the prediction of oral dosage form performance. A range of factors and methods will be considered, including imaging methods, intraluminal sampling and, models for predicting segmental/regional absorption. In addition, in vitro and in silico methods to evaluate regional drug absorption will be discussed. This will provide the basis for further work on improving predictions for the in vivo behavior of drug products in the gastrointestinal tract.

Consumption of non-digestible oligosaccharides elevates colonic alkaline phosphatase activity by up-regulating the expression of IAP-I, with increased mucins and microbial fermentation in rats fed a high-fat diet.

We have recently reported that soluble dietary fibre, glucomannan, increased colonic alkaline phosphatase (ALP) activity and the gene expression without affecting the small-intestinal activity and that colonic ALP was correlated with gut mucins (index of intestinal barrier function). We speculated that dietary fermentable carbohydrates including oligosaccharides commonly elevate colonic ALP and gene expression as well as increase mucin secretion and microbial fermentation. To test this hypothesis, male Sprague-Dawley rats were fed a diet containing 30 % lard with or without 4 % fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), raffinose (RAF) and lactulose (LAC), which are non-digestible oligosaccharides or isomalto-oligosaccharides (IMOS; some digestible oligosaccharides) for 2 weeks. Colon ALP activity, the gene expression and gut luminal variables including mucins, organic acids and microbiota were measured. Colonic ALP was significantly elevated in the FOS, RAF and LAC groups, and a similar trend was observed in the GOS group. Colonic expression of intestinal alkaline phosphatase (IAP -I), an ALP gene, was significantly elevated in the FOS, GOS and RAF groups and tended to be increased in the LAC group. Dietary FOS, GOS, RAF and LAC significantly elevated faecal mucins, caecal n-butyrate and faecal ratio of Bifidobacterium spp. Dietary IMOS had no effect on colonic ALP, mucins, organic acids and microbiota. Colon ALP was correlated with mucins, caecal n-butyrate and faecal Bifidobacterium spp. This study demonstrated that non-digestible and fermentable oligosaccharides commonly elevate colonic ALP activity and the expression of IAP-I, with increasing mucins and microbial fermentation, which might be important for protection of gut epithelial homoeostasis.

The impact of food intake on the luminal environment and performance of oral drug products with a view to in vitro and in silico simulations: a PEARRL review.

OBJECTIVES: Using the type of meal and dosing conditions suggested by regulatory agencies as a basis, this review has two specific objectives: first, to summarize our understanding on the impact of food intake on luminal environment and drug product performance and second, to summarize the usefulness and limitations of available in vitro and in silico methodologies for the evaluation of drug product performance after food intake. KEY FINDINGS: Characterization of the luminal environment and studies evaluating product performance in the lumen, under conditions suggested by regulatory agencies for simulating the fed state, are limited. Various in vitro methodologies have been proposed for evaluating drug product performance in the fed state, but systematic validation is lacking. Physiologically based pharmacokinetic (PBPK) modelling approaches require the use of in vitro biorelevant data and, to date, have been used primarily for investigating the mechanisms via which an already observed food effect is mediated. SUMMARY: Better understanding of the impact of changes induced by the meal administration conditions suggested by regulatory agencies on the luminal fate of the drug product is needed. Relevant information will be useful for optimizing the in vitro test methods and increasing the usefulness of PBPK modelling methodologies.

Gender Difference and Dietary Supplemental Vitamin B6: Impact on Colon Luminal Environment.

Colon diseases can be affected by several factors such as gender difference and dietary supplemental vitamin B6 (B6). The nutritional status of B6 is affected by gender difference, leading us to hypothesize that gender difference affects colon luminal environment, which is dependent on B6 status. To investigate this hypothesis, we fed male and female rats a diet containing 1 mg, 7 mg, or 35 mg pyridoxine HCl/kg diet for 6 wk. We found significantly higher fecal mucin levels in female rats compared to those in male rats. Supplemental B6 significantly increased fecal mucins and was particularly profound in the female rats. The abundances of cecal and fecal Akkermansia muciniphila (mucin degrader) were unaffected. The fecal mucin levels were significantly correlated with colonic free threonine and serine and with gene expression of colon MUC16, implying that the combined effect of gender and dietary B6 on fecal mucins was mediated by the alteration in the levels of such amino acids and MUC16 expression. This study further showed the significant effects of gender difference on colonic free amino acids such as threonine, ornithine, asparagine/aspartate ratio, and glutamine/glutamate ratio, cecal and fecal Lactobacillus spp. levels, and colonic gene expressions of MUC16 and TLR8, the factors relating to colon health and diseases. Therefore, our findings suggest that gender difference and dietary B6 may have an impact on colon diseases by modulating these parameters.

Glucomannan consumption elevates colonic alkaline phosphatase activity by up-regulating the expression of IAP-I, which is associated with increased production of protective factors for gut epithelial homeostasis in high-fat diet-fed rats.

We previously reported that consumption of glucomannan-containing food (lily bulb) modulates gut microbiota and increases gut immunoglobulin A (IgA, index of intestinal immune function), mucins (index of intestinal barrier function), and colonic alkaline phosphatase (ALP) activity in rats fed a high-fat (HF) diet. Small intestinal ALP has an established protective effect in inflammatory diseases, whereas little is known about the function of colonic ALP activity. We hypothesized that dietary glucomannan would increase colonic ALP activity and the gene expression in rats fed an HF diet. To test this hypothesis, male Sprague-Dawley rats were fed a diet containing 30% lard with or without 4% high or low viscous glucomannan (HGM or LGM) for 2 weeks. Dietary HGM and LGM significantly increased colonic ALP activity without affecting ALP activity in the small intestine. The colonic expression of IAP-I, an ALP gene expressed throughout the intestine, was significantly higher in the HGM and LGM groups when compared with the control group. The colonic expression of Akp3 and Alpl, other ALP genes, were not affected by HGM and LGM. Dietary HGM and LGM significantly elevated fecal levels of IgA and mucins and cecal organic acids, including n-butyrate, propionate, and lactate. Colon ALP correlated with fecal IgA, mucins, and cecal organic acids. The present study showed that dietary glucomannan elevates colonic ALP activity by up-regulation of the expression of IAP-I, which might be important for protection of gut epithelial homeostasis.

Expression profiles of human epididymis epithelial cells reveal the functional diversity of caput, corpus and cauda regions.

STUDY HYPOTHESIS: Region-specific transcriptional profiling of tissues and cultured epithelial cells from the human epididymis will predict functional specialization along the duct. STUDY FINDING: We identified the molecular signature driving functions of the caput, corpus and cauda epithelium, and determined how these differ to establish the regional differentiation of the organ. WHAT IS KNOWN ALREADY: The epithelium lining the human male genital ducts has a critical role in fertility. In particular, it controls the luminal environment in the epididymis, which is required for normal sperm maturation and reproductive competence. Studies in many animal species have largely informed our understanding of the molecular basis of epididymis function. However, there are substantial differences between species. STUDY DESIGN, SAMPLES/MATERIALS, METHODS: Using RNA sequencing on biological replicates, we described gene expression profiles for tissue from each region of the epididymis and cultured epithelial cells derived from these regions. Bioinformatic tools were then utilized to identify differentially expressed genes (DEGs) between tissues and cells from the caput, corpus and cauda. MAIN RESULTS AND THE ROLE OF CHANCE: The data showed that the caput is functionally divergent from the corpus and cauda, which have very similar transcriptomes. Interrogation of DEGs using gene ontology process enrichment analyses showed that processes of ion transport, response to hormone stimulus and urogenital tract development are more evident in the caput, while defense response processes are more important in the corpus/cauda. Consistent with these regional differences in epididymis function, we observed differential expression of transcription factors in the caput and corpus/cauda. LIMITATIONS, REASONS FOR CAUTION: Cultured caput, corpus and cauda cells may not faithfully represent the same cells in the intact organ, due to loss of hormonal signals from the testis and communication from other cell types. WIDER IMPLICATIONS OF THE FINDINGS: Our data provide a molecular characterization that will facilitate advances in understanding human epididymis epithelium biology in health and disease. They may also reveal the mechanisms coordinating epididymis luminal environment and sperm maturation. LARGE SCALE DATA: Data deposited at http://www.ncbi.nlm.nih.gov/geo/GSE72986. STUDY FUNDING AND COMPETING INTERESTS: This work was supported by the National Institutes of Health: R01HD068901 (PI: A.H.). The authors declare no conflict of interest.