Decreased sigmoidal ABCB1 (P-glycoprotein) expression in ulcerative colitis is associated with disease activity

Elevated risk of adverse effects from foodborne contaminants and drugs in inflammatory bowel disease: a review

The global burden of Inflammatory bowel disease (IBD) has been rising over the last decades. IBD is an intestinal disorder with a complex and largely unknown etiology. The disease is characterized by a chronically inflamed gastrointestinal tract, with intermittent phases of exacerbation and remission. This compromised intestinal barrier can contribute to, enhance, or even enable the toxicity of drugs, food-borne chemicals and particulate matter. This review discusses whether the rising prevalence of IBD in our society warrants the consideration of IBD patients as a specific population group in toxicological safety assessment. Various in vivo, ex vivo and in vitro models are discussed that can simulate hallmarks of IBD and may be used to study the effects of prevalent intestinal inflammation on the hazards of these various toxicants. In conclusion, risk assessments based on healthy individuals may not sufficiently cover IBD patient safety and it is suggested to consider this susceptible subgroup of the population in future toxicological assessments.

Comparative pharmacokinetics of five primary constituents in Huai-hua powder: a study on normal rats and rats with ulcerative colitis

OBJECTIVES

The goal of this research was to develop a fast, reliable, and sensitive method to simultaneously quantify five key components of Huai-hua Powder (HHP) in rat plasma with genistein served as the internal standard. Furthermore, the established method was used to perform a comparative evaluation of the pharmacokinetic properties of HHP in normal rats and rats with ulcerative colitis (UC).

METHODS

Chromatographic separation was conducted using an ACQUITY HSS T3 column held at a constant temperature of 35°C, with acetonitrile and a 0.1% formic acid solution in water employed as the mobile phases. Multiple-reaction monitoring facilitated MS operation in positive-negative-ion-switching mode. The method's validation demonstrated exceptional linearity (with a correlation coefficient of r ≥ 0.9970), and the validation tests, encompassing precision within and between days, accuracy, recovery, matrix effect, and stability; all met the predefined acceptable criteria.

KEY FINDINGS

The results revealed significant variations in the pharmacokinetic characteristics of the five components between normal and UC rats, suggesting altered drug metabolism rates and extents in the latter group.

CONCLUSIONS

These findings offer crucial scientific insights into the potential clinical application of HHP, particularly in the context of treating UC.

Evaluating the causal effect of circulating proteome on the risk of inflammatory bowel disease-related traits using Mendelian randomization

Objective

This study sought to identify circulating proteins causally linked to Inflammatory Bowel Disease (IBD) traits through a Mendelian Randomization (MR) analytical framework.

Methods

Using a large-scale, two-sample MR approach, we estimated the genetic links of numerous plasma proteins with IBD and its subtypes, leveraging information from the Inflammatory Bowel Disease Genetics Consortium. To assess the robustness of MR findings, methods like Bayesian colocalization, and Steiger filtering analysis, evaluation of protein-altering variants. Further insights into IBD's underlying mechanisms and therapeutic targets were gleaned from single-cell sequencing analyses, protein-protein interaction assessments, pathway enrichment analyses, and evaluation of drug targets.

Results

By cis-only MR analysis, we identified 83 protein-phenotype associations involving 27 different proteins associated with at least one IBD subtype. Among these proteins, DAG1, IL10, IL12B, IL23R, MST1, STAT3 and TNFRSF6B showed overlapping positive or negative associations in all IBD phenotypes. Extending to cis + trans MR analysis, we further identified 117 protein-feature associations, including 44 unique proteins, most of which were not detected in the cis-only analysis. In addition, by performing co-localization analysis and Steiger filtering analysis on the prioritized associations, we further confirmed the causal relationship between these proteins and the IBD phenotype and verified the exact causal direction from the protein to the IBD-related feature.

Conclusion

MR analysis facilitated the identification of numerous circulating proteins associated with IBD traits, unveiling protein-mediated mechanisms and promising therapeutic targets.

PANoptosis and Autophagy-Related Molecular Signature and Immune Landscape in Ulcerative Colitis: Integrated Analysis and Experimental Validation

Background

Ulcerative colitis (UC) is an autoimmune inflammatory disorder of the gastrointestinal tract. Programmed cell death (PCD), including PANoptosis and autophagy, plays roles in inflammation and immunity. This study aimed to investigate the molecular signature and immune landscape of the PANoptosis- and autophagy-related differentially expressed genes (DEGs) in UC.

Methods

Analyzing UC dataset GSE206285 yielded DEGs. Differentially expressed PANoptosis- and autophagy-related genes were identified using DEGs and relevant gene collections. Functional and pathway enrichment analyses were conducted. A protein-protein interaction (PPI) network was established to identify hub genes. TRRUST database predicted transcription factors (TFs), pivotal miRNAs, and drugs interacting with hub genes. Immune infiltration analysis, UC-associated single-cell sequencing data analysis, and construction of a competing endogenous RNA (ceRNA) network for hub genes were conducted. Machine learning identified key candidate genes, evaluated for diagnostic value via receiver operating characteristic (ROC) curves. A UC mice model verified expression of key candidate genes.

Results

Identifying ten PANoptosis-related hub DEGs and four autophagy-related hub DEGs associated them with cell chemotaxis, wound healing and positive MAPK cascade regulation. Immune infiltration analysis revealed increased immunocyte infiltration in UC patients, with hub genes closely linked to various immune cell infiltrations. Machine learning identified five key candidate genes, TIMP1, TIMP2, TIMP3, IL6, and CCL2, with strong diagnostic performance. At the single-cell level, these genes exhibited high expression in inflammatory fibroblasts (IAFs). They showed significant expression differences in the colon mucosa of both UC patients and UC mice model.

Conclusion

This study identified and validated novel molecular signatures associated with PANoptosis and autophagy in UC, potentially influencing immune dysregulation and wound healing, thus opening avenues for future research and therapeutic interventions.

Characterisation of the Circulating Transcriptomic Landscape in Inflammatory Bowel Disease Provides Evidence for Dysregulation of Multiple Transcription Factors Including NFE2, SPI1, CEBPB, and IRF2

AIM

To assess the pathobiological and translational importance of whole-blood transcriptomic analysis in inflammatory bowel disease [IBD].

METHODS

We analysed whole-blood expression profiles from paired-end sequencing in a discovery cohort of 590 Europeans recruited across six countries in the IBD Character initiative (newly diagnosed patients with Crohn's disease [CD; n = 156], ulcerative colitis [UC; n = 167], and controls [n = 267]), exploring differential expression [DESeq2], co-expression networks [WGCNA], and transcription factor involvement [EPEE, ChEA, DoRothEA]. Findings were validated by analysis of an independent replication cohort [99 CD, 100 UC, 95 controls]. In the discovery cohort, we also defined baseline expression correlates of future treatment escalation using cross-validated elastic-net and random forest modelling, along with a pragmatic ratio detection procedure.

RESULTS

Disease-specific transcriptomes were defined in IBD [8697 transcripts], CD [7152], and UC [8521], with the most highly significant changes in single genes, including CD177 (log2-fold change [LFC] = 4.63, p = 4.05 × 10-118), MCEMP1 [LFC = 2.45, p = 7.37 × 10-109], and S100A12 [LFC = 2.31, p = 2.15 × 10-93]. Significantly over-represented pathways included IL-1 [p = 1.58 × 10-11], IL-4, and IL-13 [p = 8.96 × 10-9]. Highly concordant results were obtained using multiple regulatory activity inference tools applied to the discovery and replication cohorts. These analyses demonstrated central roles in IBD for the transcription factors NFE2, SPI1 [PU.1], CEBPB, and IRF2, all regulators of cytokine signalling, based on a consistent signal across cohorts and transcription factor ranking methods. A number of simple transcriptome-based models were associated with the need for treatment escalation, including the binary CLEC5A/CDH2 expression ratio in UC (hazard ratio = 23.4, 95% confidence interval [CI] 5.3-102.0).

CONCLUSIONS

Transcriptomic analysis has allowed for a detailed characterisation of IBD pathobiology, with important potential translational implications.

Short-Chain Fatty Acid Decreases the Expression of CEBPB to Inhibit miR-145-Mediated DUSP6 and Thus Further Suppresses Intestinal Inflammation

Intestinal inflammation is a common disease which can further lead to inflammatory bowel disease and even intestinal cancer. The increasing focus has come to the role of short-chain fatty acid (SCFA) in various bowel diseases. Hence, this study was designed to explore the specific role of SCFA in intestinal inflammation. In vivo and in vitro models of intestinal inflammation were constructed by lipopolysaccharide (LPS) injection in mice and LPS treatment on intestinal epithelial cells. A possible regulatory mechanism involving SCFA, CCAAT enhancer-binding protein beta (CEBPB), microRNA-145 (miR-145), and dual-specificity phosphatase 6 (DUSP6) in intestinal inflammation was verified by ChIP assay and dual-luciferase reporter gene assay. To evaluate the effects of SCFA on LPS-treated intestinal epithelial cells, the expression of relevant genes and inflammatory factors (IL-6, TNF-α, and IL-1β) were determined. Last, the role of SCFA in vivo was explored through the scoring of disease activity index (DAI) and observation of colonic histology of LPS-treated mice. SCFA decreased the CEBPB expression in mouse colon tissues and small intestine epithelial cells induced by LPS. Furthermore, CEBPB could bind to the miR-145 promoter to inhibit its expression, thereby promoting the expression of DUSP6. In addition, SCFA improved the DAI, colonic histology, and the expression of serum inflammatory factors in LPS-treated mice and cells, noting that SCFA alleviated intestinal inflammation in vitro and in vivo. To sum up, SCFA inhibited DUSP6 by upregulating miR-145 through CEBPB repression and thus prevented the development of intestinal inflammation.

Intestinal Microbiota and Gene Expression Reveal Similarity and Dissimilarity Between Immune-Mediated Colitis and Ulcerative Colitis

Immune checkpoint inhibitors (ICIs) have become the standard of care for several cancers. However, ICI therapy has also been associated with various immune-related adverse events (irAEs). Clinical manifestations of immune-related colitis resemble those of inflammatory bowel diseases such as ulcerative colitis (UC). The composition of the bowel microflora is thought to influence the development of inflammatory bowel disease and irAE colitis. We profiled the gene expressions and microbe compositions of colonic mucosa from patients with solid cancers receiving anti-PD-L1 antibody treatment; we then compared the expression profiles associated with irAE colitis with those associated with UC. The pathway enrichment analysis revealed functional similarities between inflamed regions of irAE colitis and UC. The common enriched pathways included leukocyte extravasation and immune responses, whereas non-inflamed mucosa from patients with irAE colitis was distinct from patients with UC and was characterized by the recruitment of immune cells. A similarity between the microbiota profiles was also identified. A decreased abundance of Bacteroides species was observed in inflamed regions from both irAE colitis and UC based on a microbiota composition analysis of 16S rDNA sequencing. Pathways associated with molecule transport systems, including fatty acids, were enriched in inflamed and non-inflamed irAE colitis and inflamed UC, similar to Piphillin-inferred KEGG pathways. While UC is characterized by local regions of inflammation, ICI treatment extends to non-inflammatory regions of the colonial mucosa where immune cells are reconstituted. This analysis of the similarity and heterogeneity of irAE colitis and UC provides important information for the management of irAE colitis.

Inflammation Induces Changes in the Functional Expression of P-gp, BCRP, and MRP2: An Overview of Different Models and Consequences for Drug Disposition

The ATP-binding cassette (ABC) transporters play a key role in drug pharmacokinetics. These membrane transporters expressed within physiological barriers can be a source of pharmacokinetic variability. Changes in ABC transporter expression and functionality may consequently affect the disposition of substrate drugs, resulting in different drug exposure. Inflammation, present in several acute and chronic diseases, has been identified as a source of modulation in drug transporter expression leading to variability in drug response. Its regulation may be particularly dangerous for drugs with a narrow therapeutic index. In this context, numerous in vitro and in vivo models have shown up- or downregulation in the expression and functionality of ABC transporters under inflammatory conditions. Nevertheless, the existence of contradictory data and the lack of standardization for the models used have led to a less conclusive interpretation of these data.

Therapeutic Drug Monitoring of Second- and Third-Generation Antipsychotic Drugs-Influence of Smoking Behavior and Inflammation on Pharmacokinetics

Both inflammation and smoking can influence a drug’s pharmacokinetic properties, i.e., its liberation, absorption, distribution, metabolism, and elimination. Depending on, e.g., pharmacogenetics, these changes may alter treatment response or cause serious adverse drug reactions and are thus of clinical relevance. Antipsychotic drugs, used in the treatment of psychosis and schizophrenia, should be closely monitored due to multiple factors (e.g., the narrow therapeutic window of certain psychotropic drugs, the chronicity of most mental illnesses, and the common occurrence of polypharmacotherapy in psychiatry). Therapeutic drug monitoring (TDM) aids with drug titration by enabling the quantification of patients’ drug levels. Recommendations on the use of TDM during treatment with psychotropic drugs are presented in the Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology; however, data on antipsychotic drug levels during inflammation or after changes in smoking behavior—both clinically relevant in psychiatry—that can aid clinical decision making are sparse. The following narrative review provides an overview of relevant literature regarding TDM in psychiatry, particularly in the context of second- and third-generation antipsychotic drugs, inflammation, and smoking behavior. It aims to spread awareness regarding TDM (most pronouncedly of clozapine and olanzapine) as a tool to optimize drug safety and provide patient-tailored treatment.

Therapeutic Drug Monitoring of Second- and Third-Generation Antipsychotic Drugs—Influence of Smoking Behavior and Inflammation on Pharmacokinetics

Both inflammation and smoking can influence a drug’s pharmacokinetic properties, i.e., its liberation, absorption, distribution, metabolism, and elimination. Depending on, e.g., pharmacogenetics, these changes may alter treatment response or cause serious adverse drug reactions and are thus of clinical relevance. Antipsychotic drugs, used in the treatment of psychosis and schizophrenia, should be closely monitored due to multiple factors (e.g., the narrow therapeutic window of certain psychotropic drugs, the chronicity of most mental illnesses, and the common occurrence of polypharmacotherapy in psychiatry). Therapeutic drug monitoring (TDM) aids with drug titration by enabling the quantification of patients’ drug levels. Recommendations on the use of TDM during treatment with psychotropic drugs are presented in the Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology; however, data on antipsychotic drug levels during inflammation or after changes in smoking behavior—both clinically relevant in psychiatry—that can aid clinical decision making are sparse. The following narrative review provides an overview of relevant literature regarding TDM in psychiatry, particularly in the context of second- and third-generation antipsychotic drugs, inflammation, and smoking behavior. It aims to spread awareness regarding TDM (most pronouncedly of clozapine and olanzapine) as a tool to optimize drug safety and provide patient-tailored treatment.

Therapeutic Drug Monitoring of Second- and Third-Generation Antipsychotic Drugs-Influence of Smoking Behavior and Inflammation on Pharmacokinetics

Both inflammation and smoking can influence a drug's pharmacokinetic properties, i.e., its liberation, absorption, distribution, metabolism, and elimination. Depending on, e.g., pharmacogenetics, these changes may alter treatment response or cause serious adverse drug reactions and are thus of clinical relevance. Antipsychotic drugs, used in the treatment of psychosis and schizophrenia, should be closely monitored due to multiple factors (e.g., the narrow therapeutic window of certain psychotropic drugs, the chronicity of most mental illnesses, and the common occurrence of polypharmacotherapy in psychiatry). Therapeutic drug monitoring (TDM) aids with drug titration by enabling the quantification of patients' drug levels. Recommendations on the use of TDM during treatment with psychotropic drugs are presented in the Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology; however, data on antipsychotic drug levels during inflammation or after changes in smoking behavior-both clinically relevant in psychiatry-that can aid clinical decision making are sparse. The following narrative review provides an overview of relevant literature regarding TDM in psychiatry, particularly in the context of second- and third-generation antipsychotic drugs, inflammation, and smoking behavior. It aims to spread awareness regarding TDM (most pronouncedly of clozapine and olanzapine) as a tool to optimize drug safety and provide patient-tailored treatment.

Adaptations in gastrointestinal physiology after sleeve gastrectomy and Roux-en-Y gastric bypass

Linked to the growing obesity epidemic, demand for bariatric and metabolic surgery has increased, the most common procedures being sleeve gastrectomy and Roux-en-Y gastric bypass. Originally, bariatric procedures were described as purely restrictive, malabsorptive, or combined restrictive-malabsorptive procedures limiting food intake, nutrient absorption, or both. Nowadays, anatomical alterations are known to affect gastrointestinal physiology, which in turn affects the digestion and absorption of nutrients and drugs. Therefore, understanding gastrointestinal physiology is crucial to prevent postoperative nutritional deficiencies and to optimise postoperative drug therapy. Preclinical and clinical research indicates that sleeve gastrectomy accelerates liquid and solid gastric emptying and small intestinal transit, and increases bile acid serum levels, whereas its effects on gastrointestinal acidity, gastric and pancreatic secretions, surface area, and colonic transit remain largely unknown. Roux-en-Y gastric bypass diminishes gastric acid secretion, accelerates liquid gastric emptying, and increases bile acid serum levels, but its effects on intestinal pH, solid gastric emptying, intestinal transit time, gastric enzyme secretions, and surface area remain largely unknown. In this Review, we summarise current knowledge of the effects of these two procedures on gastrointestinal physiology and assess the knowledge gaps.

CYP3A5 Genotype as a Potential Pharmacodynamic Biomarker for Tacrolimus Therapy in Ulcerative Colitis in Japanese Patients

Tacrolimus has been used to induce remission in patients with steroid-refractory ulcerative colitis. It poses a problem of large individual differences in dosage necessary to attain target blood concentration and, often, this leads to drug inefficacy. We examined the difference in mRNA expression levels of ATP binding cassette transporter B1 (ABCB1) between inflamed and non-inflamed tissues, and the influence of CYP3A5 genotype on tacrolimus therapy. The mRNA expression of CYP3A4 in colonic mucosa and that of cytochrome p450 3A5 (CYP3A5) and ABCB1 in inflamed and non-inflamed areas were examined in 14 subjects. The mRNA expression levels of CYP3A5 were higher than that of CYP3A4. The mRNA expression of ABCB1 was lower in the inflamed than in the non-inflamed mucosa, despite that of CYP3A5 mRNA level being not significantly changed. Hence, the deterioration of the disease is related to the reduction of the barrier in the inflamed mucosa. The relationship between CYP3A5 genotype and blood concentration, dose, and concentration/dose (C/D) ratio of tacrolimus in 15 subjects was studied. The tacrolimus dose to maintain equivalent blood concentrations was lower in CYP3A5*3/*3 than in CYP3A5*1 carriers, and the C/D ratio was significantly higher in the latter. Thus, CYP3A5 polymorphism information played a role in determining the initial dose of tacrolimus. Furthermore, since the effect of tacrolimus appears earlier in CYP3A5*3/*3 than in CYP3A5*1/*1 and *1/*3, it seems necessary to change the evaluation time of therapeutic effect by CYP3A5 genotype. Additionally, the relationship between CYP3A5 genotype and C/D ratio of tacrolimus in colonic mucosa was investigated in 10 subjects. Tacrolimus concentration in the mucosa was two-fold higher in CYP3A5*3/*3 than in CYP3A5*1 carriers, although no significant difference in tacrolimus-blood levels was observed. Therefore, the local concentration of tacrolimus affected by CYP3A5 polymorphism might be related to its therapeutic effect.

Crohn's Disease Is Associated with Decreased CYP3A4 and P-Glycoprotein Protein Expression

Cytochrome P450 (CYP) 3A4 and P-glycoprotein (P-gp) have broad substrate overlap and are involved in the metabolism and transport of nearly 50% of currently prescribed medications. In the intestine, CYP3A4 and P-gp are coexpressed in the enterocytes at the intestinal villous tip and act in a coordinated manner to limit drug and xenobiotic oral bioavailability prior to further metabolism and disposition in the liver. Crohn's disease (CD), a form of inflammatory bowel disease, introduces a transmural intestinal insult that disrupts the intestinal barrier function; it therefore has the potential to affect intestinal drug metabolism and transport. We hypothesized that individuals with CD have reduced intestinal expression of CYP3A4 and P-gp. We obtained intestinal biopsy samples from individuals with and without CD and quantified the expression of CYP3A4 and P-gp. When we carried out Western analysis for protein expression, we observed a significant reduction in ileal (45% decrease) and colonic (78% decrease) CYP3A4 protein expression in subjects with CD compared with those without. Similarly, an 85% reduction in colonic P-gp protein expression was seen in the CD patients. Our data highlight important and novel findings pertaining to CD-associated changes to the intestinal expression of CYP3A4 and P-gp that are of relevance to better predict substrate drug dosing for patients with CD.

Transcriptomic Landscape of Treatment-Naïve Ulcerative Colitis

BACKGROUND AND AIMS

Ulcerative colitis [UC] is a chronic inflammatory disease that effects the gastrointestinal tract and is considered one of the most prominent and common forms of inflammatory bowel disease [IBD]. This study aimed to define and describe the entire transcriptomic landscape in a well-stratified, treatment-naïve UC patient population compared with control patients by using next-generation technology, RNA-Seq.

METHODS

Mucosal biopsies from treatment-naïve UC patients [n = 14], and healthy controls [n = 16] underwent RNA-Seq. Principal component analysis [PCA], cell deconvolution methods, and diverse statistical methods were applied to obtain and characterise a dataset of significantly differentially expressed genes [DEGs].

RESULTS

Analyses revealed 1480 significantly DEGs in treatment-naïve UC when compared with controls. Cell populations of monocytes, T cells, neutrophils, B cells/ lymphoid cells, and myeloid cells were increased during inflammation, whereas the fraction of epithelial cells were reduced in UC, which is reflected by the DEGs; 79 DEGs were identified as IBD susceptibility genes, and 58 DEGs were expressed in a gender-specific manner. MUC5B, REG3A, DEFA5, and IL33 might be considered as colorectal cancer [CRC] risk factors following UC in males. AQP9 together with CLDN2 may have a role regulating tissue-specific physiological properties in tight junctions in UC. An additional functional role for AQP9 in the synthesis and/or the function of mucus can be implied.

CONCLUSIONS

This study reveals new potential players in UC pathogenesis in general, and provides evidence for a gender-dependent pathogenesis for UC. These results can be useful for the development of personalised treatment strategies for UC in the future.

ATP-binding cassette subfamily B member 1 1236C/T polymorphism significantly affects the therapeutic outcome of tacrolimus in patients with refractory ulcerative colitis

BACKGROUND AND AIM

Tacrolimus is now considered to be one of the main therapeutic options for refractory ulcerative colitis. Both cytochrome P-450 3A5 (CYP3A5) and ATP-binding cassette subfamily B member 1 (ABCB1) associated with tacrolimus metabolism are known to have several genetic polymorphisms. However, it remains controversial whether these polymorphisms affect the therapeutic efficacy for ulcerative colitis. We aimed to investigate the influence of both CYP3A5 and ABCB1 polymorphisms on the efficacy of tacrolimus in ulcerative colitis treatment under the tight dose-adjusting strategy.

METHODS

Sixty-one Japanese patients with ulcerative colitis treated with tacrolimus were enrolled retrospectively. Tacrolimus treatment was performed using the tight dose-adjusting strategy. Genotyping for CYP3A5*3, ABCB1 1236C>T, 2677G>A,T, and 3435C>T were performed, and the clinical outcomes at 12 weeks after the initiation of tacrolimus were compared among the genotypes.

RESULTS

There was no association between the CYP3A5 genotypes and therapeutic efficacy. In contrast, a significant association was observed with the ABCB1 1236C > T polymorphism and therapeutic efficacy. The ABCB1 1236CC+CT groups (n = 41) had a significantly higher response rate (73% vs 35%; P = 0.004) and remission rate (61% vs 20%; P = 0.002) than the TT group (n = 20). The multivariate logistic regression analysis also revealed that ABCB1 1236C>T was identified as an independent factor associated with remission.

CONCLUSIONS

ABCB1 1236C>T polymorphism significantly affects the therapeutic efficacy of tarcolimus at 12 weeks under the tight dose-adjusting treatment for ulcerative colitis.

Comparison of Cytokine and Efflux Transporter Expression in Pediatric Versus Adult-onset Ulcerative Colitis

OBJECTIVES

Ulcerative colitis (UC), a chronic inflammation of the colon, is often more severe in children than adults. Identification of altered expression of efflux transporters, cytokines, and suppressor of cytokine signaling (SOCS) molecules in pediatric versus adult patients could provide insight into the differential molecular patterns related to the age and disease pathology.

METHODS

Mucosal samples from terminal ileum and colon in pediatric (9 UC-New, 4 UC-Remission) and adult (9 UC-New, 8 UC-Remission) patients were compared with healthy subjects (15 children and 10 adults) for mRNA expressions of several efflux transporters, cytokines, and SOCS molecules.

RESULTS

The inflamed colon interleukin (IL)-6, IL-17A, and interferon-γ levels were elevated in UC-New subgroups but close to control values in UC-Remission. IL-1β expression was increased only in UC-New children. Interestingly, uninflamed ileum also showed increased IL-6 and IL-1β levels in UC-New subgroups. SOCS1/SOCS3 expression pattern followed a trend observed for inflammatory cytokines only in children. Both children and adults had decreased multidrug resistance protein 1 expression in colon, which inversely correlated with disease score, IL-6 and interferon-γ levels in UC-New children. IL-2 expression was upregulated in UC-Remission, compared with controls.

CONCLUSIONS

Efflux transporter expression varies between UC children and adults except for decreased multidrug resistance protein 1. UC is characterized by a dysregulated TH1 and TH17 cytokine response irrespective of age at disease onset, with higher cytokine levels detected in children. Increased IL-2 levels in remission imply a protective role for regulatory T cells (Tregs).

CYP3A4 Activity is Markedly Lower in Patients with Crohn's Disease

BACKGROUND

Disease-dependent changes in the activity of drug metabolizing enzymes and transporters, such as Cytochrome P450 (CYP) 3A4 and P-glycoprotein (P-gp), are thought to have a major influence on the disposition of shared substrates. However, little is known regarding the in vivo relevance of these 2 proteins during drug therapy for gastrointestinal diseases. Our aim was to elucidate the activity of CYP3A4 and P-gp in subjects with Crohn's disease (CD) and to evaluate their influence on budesonide pharmacokinetics.

METHODS

A detailed pharmacokinetic assessment was conducted in 8 individuals diagnosed with CD on stable doses of oral budesonide, a putative shared CYP3A4, and P-gp substrate, where hepatic and intestinal CYP3A4 activity were also assessed using intravenous and oral midazolam. In addition, oral fexofenadine was used as an in vivo probe for P-gp activity.

RESULTS

Budesonide area under the curve was highly variable between subjects but similar to previously reported values in healthy subjects. The hepatic and intestinal extraction ratios for midazolam were 0.11 ± 0.06 and 0.64 ± 0.25, respectively; however, CYP3A4 activity was nearly 5-fold lower in our CD cohort compared with published data among healthy subjects. Multivariate regression revealed that only 25% budesonide clearance could be explained based on midazolam or fexofenadine clearance.

CONCLUSIONS

Midazolam and fexofenadine disposition profile did not predict budesonide clearance. However, we observed a marked reduction in vivo CYP3A4 activity among individuals with CD. Therefore, changes in CYP3A4 activity in disease states such as CD may be a heretofore underappreciated determinant of variation in drug responsiveness in CD.

Mori Cortex regulates P-glycoprotein in Caco-2 cells and colons from rats with experimental colitis via direct and gut microbiota-mediated mechanisms

Mori cortex enhances intestinal epithelial barrier function by up-regulating P-glycoproteinviadirect and gut microbiota-mediated mechanisms.

Abundance of Hepatic Transporters in Caucasians: A Meta-Analysis

This study aimed to derive quantitative abundance values for key hepatic transporters suitable for in vitro–in vivo extrapolation within a physiologically based pharmacokinetic modeling framework. A meta-analysis was performed whereby data on abundance measurements, sample preparation methods, and donor demography were collated from the literature. To define values for a healthy Caucasian population, a subdatabase was created whereby exclusion criteria were applied to remove samples from non-Caucasian individuals, those with underlying disease, or those with subcellular fractions other than crude membrane. Where a clinically relevant active genotype was known, only samples from individuals with an extensive transporter phenotype were included. Authors were contacted directly when additional information was required. After removing duplicated samples, the weighted mean, geometric mean, standard deviation, coefficient of variation, and between-study homogeneity of transporter abundances were determined. From the complete database containing 24 transporters, suitable abundance data were available for 11 hepatic transporters from nine studies after exclusion criteria were applied. Organic anion transporting polypeptides OATP1B1 and OATP1B3 showed the highest population abundance in healthy adult Caucasians. For several transporters, the variability in abundance was reduced significantly once the exclusion criteria were applied. The highest variability was observed for OATP1B3 > OATP1B1 > multidrug resistance protein 2 > multidrug resistance gene 1. No relationship was found between transporter expression and donor age. To our knowledge, this study provides the first in-depth analysis of current quantitative abundance data for a wide range of hepatic transporters, with the aim of using these data for in vitro–in vivo extrapolation, and highlights the significance of investigating the background of tissue(s) used in quantitative transporter proteomic studies. Similar studies are now warranted for other ethnicities.

Expression and localization of p-glycoprotein, multidrug resistance protein 4, and breast cancer resistance protein in the female lower genital tract of human and pigtailed macaque

Antiretroviral drug absorption and disposition in cervicovaginal tissue is important for the effectiveness of vaginally or orally administered drug products in preexposure prophylaxis (PrEP) of HIV-1 sexual transmission to women. Therefore, it is imperative to understand critical determinants of cervicovaginal tissue pharmacokinetics. This study aimed to examine the mRNA expression and protein localization of three efflux transporters, P-glycoprotein (P-gp), multidrug resistance-associated protein 4 (MRP4), and breast cancer resistance protein (BCRP), in the lower genital tract of premenopausal women and pigtailed macaques. Along the human lower genital tract, the three transporters were moderately to highly expressed compared to colorectal tissue and liver, as revealed by real-time reverse transcriptase polymerase chain reaction (RT-PCR). In a given genital tract segment, the transporter with the highest expression level was either BCRP or P-gp, while MRP4 was always expressed at the lowest level among the three transporters tested. The immunohistochemical staining showed that P-gp and MRP4 were localized in multiple cell types including epithelial cells and vascular endothelial cells. BCRP was predominantly localized in the vascular endothelial cells. Differences in transporter mRNA level and localization were observed among endocervix, ectocervix, and vagina. Compared to human tissues, the macaque cervicovaginal tissues displayed comparable expression and localization patterns of the three transporters, although subtle differences were observed between the two species. The role of these cervicovaginal transporters in drug absorption and disposition warrants further studies. The resemblance between human and pigtailed macaque in transporter expression and localization suggests the utility of the macaque model in the studies of human cervicovaginal transporters.

Downregulation of expression of xenobiotic efflux genes is associated with pelvic pouch inflammation in ulcerative colitis

BACKGROUND

As many as 50% of patients with ulcerative colitis who have undergone ileal pouch-anal anastomosis develop de novo inflammation in the ileal pouch after surgery. With the use of microarray technology, we investigated what gene expression changes occur in the pelvic pouch after surgery for ulcerative colitis and how these changes vary by pouch outcome.

METHODS

Patients who had undergone ileal pouch-anal anastomosis and closure of ileostomy had biopsy specimens from the pouch and pre-pouch ileum prospectively collected. The subjects were allocated into 4 outcome groups: no pouchitis, pouchitis, Crohn's disease-like phenotype, and familial adenomatous polyposis controls. RNA was extracted and transcriptomes were analyzed using a genome-wide approach. The statistical significance of each gene was assessed, and raw P values were corrected for multiple comparisons.

RESULTS

The expression levels of 2733 transcripts in the pouch were significantly associated with outcome. These genes could be classified into 3 categories: regulation of the immune system, modification of the extracellular matrix, and xenobiotic activity. Contrary to the first 2 categories, genes involved in xenobiotic activity, such as ABCB1, had lower expression in the pouchitis and Crohn's disease-like groups compared with the no pouchitis and familial adenomatous polyposis groups.

CONCLUSIONS

Transporters of compounds including xenobiotics are downregulated in recurrent disease after ileal pouch-anal anastomosis, whereas inflammatory pathways are upregulated. These findings corroborate the hypothesis that changes in barrier function could contribute to development of intestinal inflammation.

Expression of membrane drug efflux transporters in the sigmoid colon of HIV-infected and uninfected men

The use of antiretroviral therapy (ART) as pre-exposure prophylaxis (PrEP) has gained global attention as a promising HIV prevention strategy in men who have sex with men. Permeability of these agents in the rectal mucosa may be partially regulated by interactions with drug efflux transporters, P-glycoprotein (P-gp), multidrug resistance-associated proteins (MRPs) and/or breast cancer resistance protein (BCRP). The objective of this work was to investigate the expression of drug efflux transporters in recto-sigmoid colon tissues of HIV-infected and uninfected men, and evaluate the association of ART and/or HIV infection with drug transporter expression. MDR1/P-gp, MRPs (1-4) and BCRP mRNA and protein expression were detected in sigmoid colon biopsies of HIV-uninfected individuals. Biopsies from HIV-infected, ART-naïve participants revealed a significant downregulation of P-gp and MRP2 protein levels compared to HIV-uninfected individuals. Biopsies from HIV-infected ART-treated patients showed 1.9-fold higher P-gp protein expression and 1.5-fold higher MRP2 protein expression compared to the ones obtained from the HIV-infected ART-naïve patients. This is a first report demonstrating that HIV infection or ART could alter expression of drug efflux transporters in gut mucosa which in turn could affect the permeability of PrEP antiretroviral agents across this barrier, a highly vulnerable site of HIV transmission.

Combining gene expression microarray- and cluster analysis with sequence-based predictions to identify regulators of IL-13 in allergy

The Th2 cytokine IL-13 plays a key role in allergy, by regulating IgE, airway hyper secretion, eosinophils and mast cells. In this study, we aimed to identify novel transcription factors (TFs) that potentially regulated IL-13. We analyzed Th2 polarized naïve T cells from four different blood donors with gene expression microarrays to find clusters of genes that were correlated or anti-correlated with IL13. These clusters were further filtered, by selecting genes that were functionally related. In these clusters, we identified three transcription factors (TFs) that were predicted to regulate the expression of IL13, namely CEBPB, E2F6 and AHR. siRNA mediated knockdowns of these TFs in naïve polarized T cells showed significant increases of IL13, following knockdown of CEBPB and E2F6, but not AHR. This suggested an inhibitory role of CEBPB and E2F6 in the regulation of IL13 and allergy. This was supported by analysis of E2F6, but not CEBPB, in allergen-challenged CD4+ T cells from six allergic patients and six healthy controls, which showed decreased expression of E2F6 in patients. In summary, our findings indicate an inhibitory role of E2F6 in the regulation of IL-13 and allergy. The analytical approach may be generally applicable to elucidate the complex regulatory patterns in Th2 cell polarization and allergy.

ABCB1 (P-glycoprotein) reduces bacterial attachment to human gastrointestinal LS174T epithelial cells

The aim of this project was to show elevated P-glycoprotein (P-gp) expression decreasing bacterial association with LS174T human gastrointestinal cells, and that this effect could be reversed upon blocking functional P-gp efflux. Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Lactobacillus acidophilus and numerous strains of Escherichia coli, from commensal to enteropathogenic and enterohaemorrhagic strains (O157:H7) were fluorescently labelled and incubated on LS174T cultures either with or without P-gp amplification using rifampicin. PSC-833 was used as a potent functional P-gp blocking agent. Staphylococcus and Pseudomonas displayed the greatest association with the LS174T cells. Surprisingly, lactobacilli retained more fluorescence than enteropathogenic-E. coli in this system. Irrespective of attachment differences between the bacterial species, the increase in P-gp protein expression decreased bacterial fluorescence by 25-30%. This included the GFP-labelled E. coli, and enterohaemorrhagic E. coli (O157:H7). Blocking P-gp function through the co-administration of PSC-833 increased the amount of bacteria associated with P-gp expressing LS174T cells back to control levels. As most bacteria were affected to the same degree, irrespective of pathogenicity, it is unlikely that P-gp has a direct influence on adhesion of bacteria, and instead P-gp may be playing an indirect role by secreting a bank of endogenous factors or changing the local environment to one less suited to bacterial growth in general.

Immunological response as a source to variability in drug metabolism and transport

Through the last decades it has become increasingly evident that disease-states involving cytokines affect the pharmacokinetics of drugs through regulation of expression and activity of drug metabolizing enzymes, and more recently also drug transporters. The clinical implication is however difficult to predict, since these effects are dependent on the degree of inflammation and may be changed when the diseases are treated. This article will give an overview of the present understanding of the effects of cytokines on cytochrome P450 enzymes and drug transporters, and highlight the importance of considering these issues in regard to increasing use of the relatively new class of drugs, namely therapeutic proteins.

The role of P-glycoprotein and breast cancer resistance protein (BCRP) in bacterial attachment to human gastrointestinal cells

BACKGROUND AND AIMS

Active efflux proteins such as P-glycoprotein (P-gp) are thought to have a protective role in the intestinal tract by preventing xenotoxin absorption. Some bacteria also need to adhere to the intestinal tract before causing disease through adhesin secretion. Thus, this study was initiated to examine whether any association exists between bacterial adhesion.

METHODS

Three human cell lines (Caco2, RKO, and MCF7), and 6 species of bacteria were used in this study (Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Klebsiella pneumoniae, Clostridium sporogenes and Pseudomonas aeruginosa). Following incubation of our cells with active efflux inhibitors, bacteria incubated with a stable fluorescent dye were co-incubated at 37°C for various times up to 240min. Fluorescence intensity was used to compare bacterial attachment to these cell lines with either normal efflux protein expression or with induction or inhibition of efflux proteins.

RESULTS

P-gp inhibition by either PSC-833 or GF120918 resulted in a significant increase of all bacterial attachment to Caco2 cells up to 3 fold. RKO cells and MCF7 cells did not alter their bacterial attachment with PSC-833. Fumitremorgen C, a dedicated BCRP inhibitor had no effect. In addition, rifampicin, a P-gp inducer, resulted in some limited reduction in Salmonella and Klebsiella attachment only.

CONCLUSIONS

These results indicate P-gp expression may contribute to the resistance of potential bacterial toxicity, by preventing them adhering to human enterocytes cells in the gastrointestinal tract, which may reduce the risk or intensity of gastrointestinal disorders.

Intestinal inflammation and the enterocyte transportome

Diarrhoea is a hallmark of intestinal inflammation. The mechanisms operating in acute inflammation of the intestine are well characterized and are related to regulatory changes induced by inflammatory mediators such as prostaglandins, cytokines or reactive oxygen species, along with leakage due to epithelial injury and changes in permeability. In chronic colitis, however, the mechanisms are less well known, but it is generally accepted that both secretory and absorptive processes are inhibited. These disturbances in ionic transport may be viewed as an adaptation to protracted inflammation of the intestine, since prolonged intense secretion may be physiologically unacceptable in the long term. Mechanistically, the changes in transport may be due to adjustments in the regulation of the different processes involved, to broader epithelial alterations or frank damage, or to modulation of the transportome in terms of expression. In the present review, we offer a summary of the existing evidence on the status of the transportome in chronic intestinal inflammation.

ABCB1 single-nucleotide polymorphisms determine tacrolimus response in patients with ulcerative colitis

Tacrolimus (Tac) is effective in the treatment of steroid-refractory ulcerative colitis (UC); however, nonresponse and unpredictable side effects are major limitations. Because Tac response in patients who have undergone solid-organ transplantation has been associated with the presence of variants in CYP3A and ABCB1, we elucidated the contributions of CYP3A4*1B and CYP3A5*3 and of ABCB1 1236C>T, 2677G>T,A, and 3435C>T polymorphisms to Tac response in 89 patients with UC. Short-term remission and response were achieved in 61 and 14% of the patients, respectively, and were associated with colectomy-free survival. In a linear logistic regression model, patients with homozygous variants for one of the three ABCB1 alleles showed significantly higher short-term remission rates as compared with those of other genotypes. The effects held true after multivariate analysis including multiple comparisons and were more pronounced after correction for dose-adjusted Tac blood trough levels. We suggest that ABCB1, but not CYP3A5, may predict short-term remission of Tac in steroid-refractory UC.

P-glycoprotein: tissue distribution, substrates, and functional consequences of genetic variations

P-glycoprotein (ABCB1, MDR1) belongs to the ABC transporter family transporting a wide range of drugs and xenobiotics from intra- to extracellular at many biological interfaces such as the intestine, liver, blood-brain barrier, and kidney. The ABCB1 gene is highly polymorphic. Starting with the observation of lower duodenal protein expression and elevated digoxin bioavailability in relation to the 3435C>T single nucleotide polymorphism, hundreds of pharmacokinetic and outcome studies have been performed, mostly genotyping 1236C>T, 2677G>T/A, and 3435C>T. Though some studies pointed out that intracellular concentrations of anticancer drugs, for example, within lymphocytes, might be affected by ABCB1 variants resulting in differential outcome, current knowledge of the functional significance genetic variants of ABC membrane transporters does not allow selection of a particular SNP to predict an individual's pharmacokinetics.