Mesalamine and azathioprine modulate junctional complexes and restore epithelial barrier function in intestinal inflammation

Azathioprine promotes intestinal epithelial cell differentiation into Paneth cells and alleviates ileal Crohn's disease severity

Paneth cells (PCs), a subset of intestinal epithelial cells (IECs) found at the base of small intestinal crypts, play an essential role in maintaining intestinal homeostasis. Altered PCs function is associated with diverse intestinal pathologies, including ileal Crohn's disease (CD). CD patients with ileal involvement have been previously demonstrated to display impairment in PCs and decreased levels of anti-microbial peptides. Although the immunosuppressive drug Azathioprine (AZA) is widely used in CD therapy, the impact of AZA on IEC differentiation remains largely elusive. In the present study, we hypothesized that the orally administered drug AZA also exerts its effect through modulation of the intestinal epithelium and specifically via modulation of PC function. AZA-treated CD patients exhibited an ileal upregulation of AMPs on both mRNA and protein levels compared to non-AZA treated patients. Upon in vitro AZA stimulation, intestinal epithelial cell line MODE-K exhibited heightened expression levels of PC marker in concert with diminished cell proliferation but boosted mitochondrial OXPHOS activity. Moreover, differentiation of IECs, including PCs differentiation, was boosted in AZA-treated murine small intestinal organoids and was associated with decreased D-glucose consumption and decreased growth rates. Of note, AZA treatment strongly decreased Lgr5 mRNA expression as well as Ki67 positive cells. Further, AZA restored dysregulated PCs associated with mitochondrial dysfunction. AZA-dependent inhibition of IEC proliferation is accompanied by boosted mitochondria function and IEC differentiation into PC.

Oral Formulation of 5-Aminosalicylic Acid-Hemoglobin Bio-Adhesive Nanoparticles Enhance Therapeutic Efficiency in Ulcerative Colitis Mice: A Preclinical Evaluation

The oral formulation design for colon-specific drug delivery brings some therapeutic benefits in the ulcerative colitis treatment. We recently reported the specific delivery of hemoglobin nanoparticles-conjugating 5-aminosalicylic acid (5-ASA-HbNPs) to the inflamed site. In the current study, the therapeutic effect of the 5-ASA-HbNPs formulation was confirmed in vivo. This evaluation of 5-ASA-HbNPs not only shows longer colonic retention time due to adhesive properties, also provides full support for it as compared with free 5-ASA. It was considered as a suitable bio-adhesive nanoparticle with mucoadhesive property to pass through the mucus layer and accumulate into the mucosa. In UC model mice, a two-fold decrease in the disease activity indexes and colon weight/length ratios was significantly observed in the group treated with 5-ASA-HbNPs. This group received one percent of the standard dosage of 5-ASA (50 μg/kg), while, a similar result was observed for a significant amount of free 5-ASA (5 mg/kg). Furthermore, microscopic images of histological sections of the extracted colons demonstrated that the 5-ASA-HbNPs and 5-ASA groups displayed instances of inflammatory damage within the colon. However, in comparison to the colitis group, the extent of this damage was relatively moderate, suggesting 5-ASA-HbNPs improved therapeutic efficacy with the lower dosage form.

The epithelium takes the stage in asthma and inflammatory bowel diseases

The epithelium is a dynamic barrier and the damage to this epithelial layer governs a variety of complex mechanisms involving not only epithelial cells but all resident tissue constituents, including immune and stroma cells. Traditionally, diseases characterized by a damaged epithelium have been considered "immunological diseases," and research efforts aimed at preventing and treating these diseases have primarily focused on immuno-centric therapeutic strategies, that often fail to halt or reverse the natural progression of the disease. In this review, we intend to focus on specific mechanisms driven by the epithelium that ensure barrier function. We will bring asthma and Inflammatory Bowel Diseases into the spotlight, as we believe that these two diseases serve as pertinent examples of epithelium derived pathologies. Finally, we will argue how targeting the epithelium is emerging as a novel therapeutic strategy that holds promise for addressing these chronic diseases.

Arjunolic acid protects the intestinal epithelial barrier, ameliorating Crohn's disease-like colitis by restoring gut microbiota composition and inactivating TLR4 signalling

BACKGROUND AND AIMS

Crohn's disease (CD) is characterized by an overabundance of epithelial cell death and an imbalance in microflora, both of which contribute to the dysfunction of the intestinal barrier. Arjunolic acid (AA) has anti-apoptotic effects and regulates microbiota efficacy. The objective of this study was to assess the impact of the treatment on colitis resembling Crohn's disease, along with exploring the potential underlying mechanism.

METHODS

CD animal models were created using Il-10-/- mice, and the impact of AA on colitis in mice was evaluated through disease activity index, weight fluctuations, pathological examination, and assessment of intestinal barrier function. To clarify the direct role of AA on intestinal epithelial cell apoptosis, organoids were induced by LPS, and TUNEL staining was performed. To investigate the potential mechanisms of AA in protecting the intestinal barrier, various methods including bioinformatics analysis and FMT experiments were employed.

RESULTS

The treatment for AA enhanced the condition of colitis and the function of the intestinal barrier in Il-10-/- mice. This was demonstrated by the amelioration of weight loss, reduction in tissue inflammation score, and improvement in intestinal permeability. Moreover, AA suppressed the apoptosis of intestinal epithelial cells in Il-10-/- mice and LPS-induced colon organoids, while also reducing the levels of Bax and C-caspase-3. In terms of mechanism, AA suppressed the activation of TLR4 signaling in Il-10-/- mice and colon organoids induced by LPS. In addition, AA increased the abundance of short-chain fatty acid-producing bacteria in the stool of Il-10-/- mice, and transplantation of feces from AA-treated mice improved CD-like colitis.

CONCLUSIONS

The results of our study demonstrate that AA has a protective effect on the intestinal barrier in Crohn's disease-like colitis by preventing apoptosis. Additionally, this groundbreaking study reveals the capacity of AA to hinder TLR4 signaling and alter the makeup of the intestinal microbiome. The findings present fresh possibilities for treating individuals diagnosed with Crohn's disease. AA offers a hopeful novel strategy for managing Crohn's disease by obstructing crucial pathways implicated in intestinal inflammation and enhancing the gut microbiota.

The role of microbiota and its modulation in colonic diverticular disease

BACKGROUND

Diverticular disease (DD) is a common condition in Western countries. The role of microbiota in the pathogenesis of DD and its related symptoms has been frequently postulated since most complications of this disease are bacteria-driven and most therapies rely on microbiota modulation. Preliminary data showed fecal microbial imbalance in patients with DD, particularly when symptomatic, with an increase of pro-inflammatory and potentially pathogenetic bacteria. In addition, bacterial metabolic markers can mirror specific pathways of the disease and may be even used for monitoring treatment effects. All treatments currently suggested for DD can affect microbiota structure and metabolome compositions.

PURPOSE

Sparse evidence is available linking gut microbiota perturbations, diverticular disease pathophysiology, and symptom development. We aimed to summarize the available knowledge on gut microbiota evaluation in diverticular disease, with a focus on symptomatic uncomplicated DD, and the relative treatment strategies.

Concomitant 5-aminosalicylic acid treatment does not affect 6-thioguanine nucleotide levels in patients with inflammatory bowel disease on thiopurines

Background

There are conflicting data as to whether co-treatment with 5-aminosalicylic acid (5-ASA) in patients with inflammatory bowel disease (IBD) under azathioprine (AZA) or 6-mercaptopurine (6-MP) therapy may influence 6-thioguanine nucleotide (6-TGN) concentrations, and whether this combination puts patients at risk of side-effects. The aim of the study was to determine 6-TGN levels in patients treated with AZA/6-MP, either alone or in combination with 5-ASA.

Methods

Available blood samples from patients treated with AZA or 6-MP were retrieved from the Swiss IBD Cohort Study (SIBDCS). The eligible individuals were divided into 2 groups: those with vs. without 5-ASA co-medication. Levels of 6-TGN and 6-methylmercaptopurine ribonucleotides (6-MMPR) were determined and compared. Potential confounders were compared between the groups, and also evaluated as potential predictors for a multivariate regression model.

Results

Of the 110 patients enrolled in this analysis, 40 received concomitant 5-ASA at the time of blood sampling. The median 6-TGN levels in patients with vs. those without 5-ASA co-treatment were 261 and 257 pmol/8×108 erythrocytes, respectively (P=0.97). Likewise, there were no significant differences in 6-MMPR levels (P=0.79). Through multivariate analysis, 6-TGN levels were found to be significantly higher in non-smokers, patients without prior surgery, and those without signs of stress-hyperarousal.

Conclusions

Blood concentrations of 6-TGN and 6-MMPR did not differ between patients with vs. those without 5-ASA co-treatment. Our data warrant neither more frequent lab monitoring nor dose adaptation of AZA in patients receiving concomitant 5-ASA treatment.

Maladaptive T-Cell Metabolic Fitness in Autoimmune Diseases

Immune surveillance and adaptive immune responses, involving continuously circulating and tissue-resident T-lymphocytes, provide host defense against infectious agents and possible malignant transformation while avoiding autoimmune tissue damage. Activation, migration, and deployment of T-cells to affected tissue sites are crucial for mounting an adaptive immune response. An effective adaptive immune defense depends on the ability of T-cells to dynamically reprogram their metabolic requirements in response to environmental cues. Inability of the T-cells to adapt to specific metabolic demands may skew cells to become either hyporesponsive (creating immunocompromised conditions) or hyperactive (causing autoimmune tissue destruction). Here, we review maladaptive T-cell metabolic fitness that can cause autoimmune diseases and discuss how T-cell metabolic programs can potentially be modulated to achieve therapeutic benefits.

Stem cell-derived intestinal organoids: a novel modality for IBD

The organoids represent one of the greatest revolutions in the biomedical field in the past decade. This three-dimensional (3D) micro-organ cultured in vitro has a structure highly similar to that of the tissue and organ. Using the regeneration ability of stem cells, a 3D organ-like structure called intestinal organoids is established, which can mimic the characteristics of real intestinal organs, including morphology, function, and personalized response to specific stimuli. Here, we discuss current stem cell-based organ-like 3D intestinal models, including understanding the molecular pathophysiology, high-throughput screening drugs, drug efficacy testing, toxicological evaluation, and organ-based regeneration of inflammatory bowel disease (IBD). We summarize the advances and limitations of the state-of-the-art reconstruction platforms for intestinal organoids. The challenges, advantages, and prospects of intestinal organs as an in vitro model system for precision medicine are also discussed. Key applications of stem cell-derived intestinal organoids. Intestinal organoids can be used to model infectious diseases, develop new treatments, drug screens, precision medicine, and regenerative medicine.

Alginate-based drug carrier systems to target inflammatory bowel disease: A review

Inflammatory bowel disease (IBD) is an inflammatory disorder that affects the gastrointestinal tract. IBD has become an increasingly common condition in both developed and developing nations over the last few decades, owing to a variety of factors like a rising population and diets packed with processed and junk foods. While the root pathophysiology of IBD is unknown, treatments are focused on medications aimed to mitigate symptoms. Alginate (AG), a marine-derived polysaccharide, is extensively studied for its biocompatibility, pH sensitivity, and crosslinking nature. This polymer is thoroughly researched in drug delivery systems for IBD treatment, as it is naturally available, non-toxic, cost effective, and can be easily and safely cross-linked with other polymers to form an interconnected network, which helps in controlling the release of drugs over an extended period. There are various types of drug delivery systems developed from AG to deliver therapeutic agents; among them, nanotechnology-based systems and hydrogels are popular due to their ability to facilitate targeted drug delivery, reduce dosage, and increase the therapeutic efficiency. AG-based carrier systems are not only used for the sustained release of drug, but also used in the delivery of siRNA, interleukins, and stem cells for site directed drug delivery and tissue regenerating ability respectively. This review is focussed on pathogenesis and currently studied medications for IBD, AG-based drug delivery systems and their properties for the alleviation of IBD. Moreover, future challenges are also be discoursed to improve the research of AG in the field of biopharmaceuticals and drug delivery.

Acertannin Prevented Dextran Sulfate Sodium-induced Colitis by Inhibiting the Colonic Expression of IL-23 and TNF-α in C57BL/6J Mice

The present study investigates the effects of acertannin on colitis induced by dextran sulfate sodium (DSS) and changes in the colonic levels of the cytokines interleukin (IL)-1β, IL-6, IL-10, IL-23, tumor necrosis factor (TNF)-α, the chemokine monocyte chemoattractant protein (MCP)-1, and vascular endothelial growth factor (VEGF).We examine the following: inflammatory colitis was induced in mice by 2% DSS drinking water given ad libitum for 7 days. Red blood cell, platelets, and leukocyte counts and hematocrit (Ht), hemoglobin (Hb), and colonic cytokine and chemokine levels were measured. The disease activity index (DAI) was lower in DSS-treated mice orally administered acertannin (30 and 100 mg/kg) than in DSS-treated mice. Acertannin (100 mg/kg) inhibited reductions in the red blood cell count and Hb and Ht levels in DSS-treated mice. Acertannin prevented DDS-induced mucosal membrane ulceration of the colon and significantly inhibited the increased colonic levels of IL-23 and TNF-α. Our findings suggest that acertannin has potential as a treatment for inflammatory bowel disease (IBD).

Atypical enteropathogenic E. coli are associated with disease activity in ulcerative colitis

With increasing urbanization and industrialization, the prevalence of inflammatory bowel diseases (IBDs) has steadily been rising over the past two decades. IBD involves flares of gastrointestinal (GI) inflammation accompanied by microbiota perturbations. However, microbial mechanisms that trigger such flares remain elusive. Here, we analyzed the association of the emerging pathogen atypical enteropathogenic E. coli (aEPEC) with IBD disease activity. The presence of diarrheagenic E. coli was assessed in stool samples from 630 IBD patients and 234 age- and sex-matched controls without GI symptoms. Microbiota was analyzed with 16S ribosomal RNA gene amplicon sequencing, and 57 clinical aEPEC isolates were subjected to whole-genome sequencing and in vitro pathogenicity experiments including biofilm formation, epithelial barrier function and the ability to induce pro-inflammatory signaling. The presence of aEPEC correlated with laboratory, clinical and endoscopic disease activity in ulcerative colitis (UC), as well as microbiota dysbiosis. In vitro, aEPEC strains induce epithelial p21-activated kinases, disrupt the epithelial barrier and display potent biofilm formation. The effector proteins espV and espG2 distinguish aEPEC cultured from UC and Crohn's disease patients, respectively. EspV-positive aEPEC harbor more virulence factors and have a higher pro-inflammatory potential, which is counteracted by 5-ASA. aEPEC may tip a fragile immune-microbiota homeostasis and thereby contribute to flares in UC. aEPEC isolates from UC patients display properties to disrupt the epithelial barrier and to induce pro-inflammatory signaling in vitro.

Assessment of tissue E-cadherin and its proteolytic serum fragment in pemphigus vulgaris before and after remission: A case-control study

BACKGROUND

E-cadherin is a classic cadherin that mediates keratinocyte adhesion.

AIMS

To assess the tissue expression of E-cadherin and its proteolytic serum fragment (soluble E-cadherin) in pemphigus vulgaris (PV) before and after clinical remission compared with controls.

PATIENTS

Thirty-seven PV patients and thirty controls were enrolled. Pemphigus disease area index (PDAI) was calculated for patients at baseline and after remission. Punch biopsy specimens were taken from patients before, and after remission, and from controls for assessment of tissue E-cadherin by immunofluorescence. Similarly, serum samples were collected for assessment of serum soluble E-cadherin by ELISA.

RESULTS

Presence, intensity, and mean intensity of tissue E-cadherin were significantly reduced in PV patients before treatment compared with controls (p < 0.001). Detected E-cadherin showed mainly a basal and suprabasal distribution with cell surface and a cytoplasmic expression. Serum E-cadherin was significantly higher in patients before treatment compared with controls (p = 0.006). With remission, tissue E-cadherin presence, intensity, mean intensity, and serum E-cadherin showed statistically significant improvement (p = 0.003, <0.001, <0.001, and 0.003 respectively). Tissue E-cadherin presence and serum E-cadherin level reached values equivalent to the controls (p = 0.49 and 0.44, respectively).

CONCLUSIONS

Disruption of tissue E-cadherin and upregulation of serum soluble E-cadherin can contribute to the pathogenesis of PV. Clinical remission of PV is associated with normalization of tissue and serum E-cadherin.

Patient-derived organoids for therapy personalization in inflammatory bowel diseases

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders of the intestinal tract that have emerged as a growing problem in industrialized countries. Knowledge of IBD pathogenesis is still incomplete, and the most widely-accepted interpretation considers genetic factors, environmental stimuli, uncontrolled immune responses and altered intestinal microbiota composition as determinants of IBD, leading to dysfunction of the intestinal epithelial functions. In vitro models commonly used to study the intestinal barrier do not fully reflect the proper intestinal architecture. An important innovation is represented by organoids, 3D in vitro cell structures derived from stem cells that can self-organize into functional organ-specific structures. Organoids may be generated from induced pluripotent stem cells or adult intestinal stem cells of IBD patients and therefore retain their genetic and transcriptomic profile. These models are powerful pharmacological tools to better understand IBD pathogenesis, to study the mechanisms of action on the epithelial barrier of drugs already used in the treatment of IBD, and to evaluate novel target-directed molecules which could improve therapeutic strategies. The aim of this review is to illustrate the potential use of organoids for therapy personalization by focusing on the most significant advances in IBD research achieved through the use of adult stem cells-derived intestinal organoids.

Promoting mechanism of serum amyloid a family expression in mouse intestinal epithelial cells

Serum amyloid A (SAA) is an acute phase inflammatory protein that we previously described as a robust biomarker of colorectal inflammation in patients with ulcerative colitis (UC) in clinical remission. However, what induces SAA expression in UC remains unclear. This study demonstrates that SAA is significantly expressed in the intestinal tract of UC mouse models when compared with C-reactive protein, another inflammatory biomarker. Moreover, interleukin-6 and tumor necrosis factor-α were found to promote SAA1 expression, as were Toll-like receptor ligands flagellin and lipopolysaccharide. Furthermore, results suggested that the nuclear factor-kappa B (NF-κB) pathway may be involved in the promotion of SAA1 expression by flagellin, which was inhibited by treatment with 5-aminosalicylic acid (5-ASA). Therefore, the flagellin/NF-κB/SAA1 axis may represent one of the mechanisms by which 5-ASA suppresses intestinal inflammation.

Molecular mechanism of the TGF‑β/Smad7 signaling pathway in ulcerative colitis

Aberrant TGF‑β/Smad7 signaling has been reported to be an important mechanism underlying the pathogenesis of ulcerative colitis. Therefore, the present study aimed to investigate the effects of a number of potential anti‑colitis agents on intestinal epithelial permeability and the TGF‑β/Smad7 signaling pathway in an experimental model of colitis. A mouse model of colitis was first established before anti‑TNF‑α and 5‑aminosalicyclic acid (5‑ASA) were administered intraperitoneally and orally, respectively. Myeloperoxidase (MPO) activity, histological index (HI) of the colon and the disease activity index (DAI) scores were then detected in each mouse. Transmission electron microscopy (TEM), immunohistochemical and functional tests, including Evans blue (EB) and FITC‑dextran (FD‑4) staining, were used to evaluate intestinal mucosal permeability. The expression of epithelial phenotype markers E‑cadherin, occludin, zona occludens (ZO‑1), TGF‑β and Smad7 were measured. In addition, epithelial myosin light chain kinase (MLCK) expression and activity were measured. Anti‑TNF‑α and 5‑ASA treatments was both found to effectively reduce the DAI score and HI, whilst decreasing colonic MPO activity, plasma levels of FD‑4 and EB permeation of the intestine. Furthermore, anti‑TNF‑α and 5‑ASA treatments decreased MLCK expression and activity, reduced the expression of Smad7 in the small intestine epithelium, but increased the expression of TGF‑β. In mice with colitis, TEM revealed partial epithelial injury in the ileum, where the number of intercellular tight junctions and the expression levels of E‑cadherin, ZO‑1 and occludin were decreased, all of which were alleviated by anti‑TNF‑α and 5‑ASA treatment. In conclusion, anti‑TNF‑α and 5‑ASA both exerted protective effects on intestinal epithelial permeability in an experimental mouse model of colitis. The underlying mechanism may be mediated at least in part by the increase in TGF‑β expression and/or the reduction in Smad7 expression, which can inhibit epithelial MLCK activity and in turn reduce mucosal permeability during the pathogenesis of ulcerative colitis.

Gut barrier disruption and chronic disease

The intestinal barrier protects the host against gut microbes, food antigens, and toxins present in the gastrointestinal tract. However, gut barrier integrity can be affected by intrinsic and extrinsic factors, including genetic predisposition, the Western diet, antibiotics, alcohol, circadian rhythm disruption, psychological stress, and aging. Chronic disruption of the gut barrier can lead to translocation of microbial components into the body, producing systemic, low-grade inflammation. While the association between gut barrier integrity and inflammation in intestinal diseases is well established, we review here recent studies indicating that the gut barrier and microbiota dysbiosis may contribute to the development of metabolic, autoimmune, and aging-related disorders. Emerging interventions to improve gut barrier integrity and microbiota composition are also described.

Hemoglobin bio-adhesive nanoparticles as a colon-specific delivery system for sustained release of 5-aminosalicylic acid in the effective treatment of inflammatory bowel disease

A colonic drug delivery system was developed to specifically deliver 5-aminosalicylic acid (5-ASA) to the inflamed site by conjugating with hemoglobin nanoparticles (HbNPs). The 5-ASA-HbNPs (eight 5-ASA molecules per Hb molecule) with the size of 220 nm and zeta potential of -14.6 mV is a tailored nanoparticle able to pass through the mucus layer. The 5-ASA-HbNPs do not undergo chemical and enzymatic hydrolysis in the simulated gastrointestinal fluids over 6 h. Significantly higher cellular uptakes and prolonged release was seen for the 5-ASA-HbNPs in Caco-2 cells, compared to free 5-ASA over 72 h. In addition, 5-ASA-HbNPs revealed similar therapeutic effectiveness with free 5-ASA against tumor necrosis factor and showed less inhibitory concentration (IC50) for myeloperoxidase enzyme activity. In vivo imaging of mouse demonstrated the localization of drug in the descending colon after oral administration and about 15% of the administered dose was recovered as 5-ASA from urine in 6 h. The use of these nanoparticles with the mucus adhesion properties and permeability to intestinal epithelial cells can be a good candidate with potential application in the colonic drug delivery field.

Aging and IBD: A New Challenge for Clinicians and Researchers

Evidence from recent epidemiological data suggests that the patient population with inflammatory bowel disease (IBD) is chronologically aging. As these individuals become older, cellular senescence leads to a state of chronic inflammation. This process, known as inflammaging, is thought to be closely linked with biological aging and may be upregulated within IBD. As a consequence, we see an increased risk of aging-related disorders within IBD. In addition, we see that frailty, which results from physiologic decline, is increasing in prevalence and is associated with adverse clinical outcomes in IBD. As such, in this review we explore the potential overlapping biology of IBD and aging, discuss the risk of aging-related disorders in IBD, and describe frailty and its relation to clinical outcomes within IBD. Finally, we discuss current considerations for clinical care and potential research avenues for further investigation.

Mesalazine initiates an anti-oncogenic β-catenin / MUCDHL negative feed-back loop in colon cancer cells by cell-specific mechanisms

Chronic inflammation associated with intestinal architecture and barrier disruption puts patients with inflammatory bowel disease (IBD) at increased risk of developing colorectal cancer (CRC). Widely used to reduce flares of intestinal inflammation, 5-aminosalicylic acid derivatives (5-ASAs) such as mesalazine appear to also exert more direct mucosal healing and chemopreventive activities against CRC. The mechanisms underlying these activities are poorly understood and may involve the up-regulation of the cadherin-related gene MUCDHL (CDHR5). This atypical cadherin is emerging as a new actor of intestinal homeostasis and opposes colon tumorigenesis. Here, we showed that mesalazine increase mRNA levels of MUCDHL and of other genes involved in the intestinal barrier function in most intestinal cell lines. In addition, using gain / loss of function experiments (agonists, plasmid or siRNAs transfections), luciferase reporter genes and chromatin immunoprecipitation, we thoroughly investigated the molecular mechanisms triggered by mesalazine that lead to the up-regulation of MUCDHL expression. We found that basal transcription of MUCDHL in different CRC cell lines is regulated positively by CDX2 and negatively by β-catenin through a negative feed-back loop. However, mesalazine-stimulation of MUCDHL transcription is controlled by cell-specific mechanisms, involving either enhanced activation of CDX2 and PPAR-γ or repression of the β-catenin inhibitory effect. This work highlights the importance of the cellular and molecular context in the activity of mesalazine and suggests that its efficacy against CRC depends on the genetic alterations of transformed cells.

Development of An HPLC Method for the Determination of Mesalazine in Human Plasma by Fluorimetric Derivatization and Application to A Prototype Pharmacokinetic Study

In this study, a new, fast and sensitive HPLC method with fluorometric detection was developed for the determination of mesalazine in human plasma and applied to a pharmacokinetic study. Mesalazine was precolumn derivatized with NBD-Cl and the fluorescent derivative was separated on a C18 (150 × 4.6 mm × 2.6 μm) analytical column at 30 ºC using a mobile phase composed of acetonitrile-0.1% o-phosphoric acid in water (70:30, v/v) by isocratic elution with flow rate of 1.0 mL min^-1. The method was based on the measurement of the derivative using fluorescence detection (λ_ex = 280 nm, λ_em = 325 nm). The retention time of mesalazine is 3.08 ± 0.06 min. Nortriptiline was used as internal standard. This currently developed method was validated according to ICH criteria by evaluating the specificity, linearity, precision, accuracy and robustness. The method was determined to be linear in a concentration range of 0.25-1.5 μg mL^-1 with the correlation coefficient of 0.9997. LOD and LOQ were found to be 0.075 and 0.25 μg mL^-1, respectively. Intraday and interday RSD values were less than 5.92%. The plasma concentration-time profile and pharmacokinetic parameters such as AUC_0-t, AUC_0-∞, C_max, t_max, t_1/2, were calculated according to the assays. The presented method can certainly be used for bioequivalence and bioavailability investigations and routine analysis of the drug in plasma.

A recent update on the use of Chinese medicine in the treatment of inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic idiopathic disease that is characterized by inflammation of the gastrointestinal tract. Proper management of IBD requires both early diagnosis and novel therapies and management programs. Many reports have suggested that Chinese medicine has unique properties favorable to the treatment of IBD. However, there are no systematic analyses on this topic.

PURPOSE

This review summarizes recent studies that assessed the effects and mechanisms of Chinese medicine in the treatment of IBD in order to fully understand the advantages of Chinese medicine in the management of IBD.

METHODS

A literature search was conducted using peer-reviewed and clinical databases, including PubMed, Web of Science, ClinicalTrials.gov, MEDLINE, EMBASE, Springer LINK, Wan-fang database, the Chinese Biomedicine Database, and the China National Knowledge Infrastructure (CNKI). Keywords used were inflammatory bowel disease (including Ulcerative colitis or Crohn's disease) and Chinese medicine. All selected articles were from 1997 to 2021, and each were assessed critically for our exclusion criteria. Studies describing the pathogenesis of IBD, the effects and mechanisms of Chinese medicine in the treatment of IBD, in particular their roles in immune regulation, intestinal flora regulation, and improvement of intestinal barrier function, were included.

CONCLUSION

This review highlights recent progress in the use of Chinese medicine in the treatment of IBD. It also provides a reference for further evaluation and exploration of the potential of classical multi-herbal Chinese medicine in the treatment of IBD.

E-cadherin activating antibodies limit barrier dysfunction and inflammation in mouse inflammatory bowel disease

Deficits in gastrointestinal (GI) paracellular permeability has been implicated in etiology of Inflammatory Bowel Disease (IBD), and E-cadherin, a key component of the epithelial junctional complex, has been implicated in both barrier function and IBD. We have previously described antibodies against E-cadherin that activate cell adhesion, and in this study, we show that they increase transepithelial electrical resistance in epithelial cell monolayers in vitro. We therefore tested the hypothesis that adhesion activating E-cadherin mAbs will enhance epithelial barrier function in vivo and limit progression of inflammation in IBD. Activating mAbs to mouse E-cadherin were tested in different mouse models of IBD including the IL10-/- and adoptive T cell transfer models of colitis. Previously established histological and biomarker measures of inflammation were evaluated to monitor disease progression. Mouse E-cadherin activating mAb treatment reduced total colitis score, individual histological measures of inflammation, and other hallmarks of inflammation compared to control treatment. Activating mAbs also reduced the fecal accumulation lipocalin2 and albumin content, consistent with enhanced barrier function. Therefore, E-cadherin activation could be a potential strategy for limiting inflammation in UC.

A review of the biological and pharmacological activities of mesalazine or 5-aminosalicylic acid (5-ASA): an anti-ulcer and anti-oxidant drug

Mesalazine, also known as 5-aminosalicylic acid (5-ASA), is a synthetic drug from the family of nonsteroidal anti-inflammatory drugs (NSAIDs) used for inflammatory diseases of the gastrointestinal tract. However, 5-ASA has also been used for various other diseases due to its pharmacological effects, but they are usually scattered across various publications, which may limit further research and clinical use of this drug. This review is a summary of published information on the biological and pharmacological effects of 5-ASA with the aim of identifying its anti-oxidant role and medicinal use. 5-ASA data have been collected from 1987 to February 2021 using major databases such as Web of Science, PubMed, Elsevier, Wiley Online Library, Springer, Google Scholar, etc. According to research, the pharmacological and biological effects of 5-ASA include treatment of inflammatory bowel disease, and anti-oxidant, anti-inflammatory, antibacterial, antifungal, anticancer, anti-amyloid, gastric protection (gastroprotective), and antidiverticulosis properties. Numerous pharmacological studies have shown that 5-ASA is an anti-oxidant and anti-ulcer compound with high therapeutic potential that, if the appropriate dose is discovered, its chemical structure changes and its effectiveness is optimized, 5-ASA has been used experimentally for other diseases.

The Production and Function of Endogenous Interleukin-10 in Intestinal Epithelial Cells and Gut Homeostasis

The healthy gut is achieved and maintained through a balanced relationship between the mucosal immune system, microbial communities resident in the lumen, and the intestinal epithelium. The intestinal epithelium plays an exceptionally important role in harmonizing the interaction between the host immunity and the luminal residents, as this selectively permeable barrier separates but also allows interchange between the 2 environments. Interleukin (IL)-10 has been well established to play an important role in maintaining gut homeostasis by imparting diverse effects on a variety of cell types in this relationship. In the intestine, the source and the target of IL-10 include leukocytes and epithelial cells. Given that both the epithelium and IL-10 are essential players in supporting homeostasis, we discuss the relationship between these 2 factors, focusing on epithelial sources of IL-10 and the effects of IL-10 on the intestinal epithelium. Insight into this relationship reveals an important aspect of the innate immune function of intestinal epithelial cells.

The food additive EDTA aggravates colitis and colon carcinogenesis in mouse models

Inflammatory bowel disease is a group of conditions with rising incidence caused by genetic and environmental factors including diet. The chelator ethylenediaminetetraacetate (EDTA) is widely used by the food and pharmaceutical industry among numerous other applications, leading to a considerable environmental exposure. Numerous safety studies in healthy animals have revealed no relevant toxicity by EDTA. Here we show that, in the presence of intestinal inflammation, EDTA is surprisingly capable of massively exacerbating inflammation and even inducing colorectal carcinogenesis at doses that are presumed to be safe. This toxicity is evident in two biologically different mouse models of inflammatory bowel disease, the AOM/DSS and the IL10^−/− model. The mechanism of this effect may be attributed to disruption of intercellular contacts as demonstrated by in vivo confocal endomicroscopy, electron microscopy and cell culture studies. Our findings add EDTA to the list of food additives that might be detrimental in the presence of intestinal inflammation, but the toxicity of which may have been missed by regulatory safety testing procedures that utilize only healthy models. We conclude that the current use of EDTA especially in food and pharmaceuticals should be reconsidered. Moreover, we suggest that intestinal inflammatory models should be implemented in the testing of food additives to account for the exposure of this primary organ to environmental and dietary stress.

Regulation of Intestinal Barrier Function by Microbial Metabolites

The human gastrointestinal tract (GI) harbors a diverse population of microbial life that continually shapes host pathophysiological responses. Despite readily available abundant metagenomic data, the functional dynamics of gut microbiota remain to be explored in various health and disease conditions. Microbiota generate a variety of metabolites from dietary products that influence host health and pathophysiological functions. Since gut microbial metabolites are produced in close proximity to gut epithelium, presumably they have significant impact on gut barrier function and immune responses. The goal of this review is to discuss recent advances on gut microbial metabolites in the regulation of intestinal barrier function. While the mechanisms of action of these metabolites are only beginning to emerge, they mainly point to a small group of shared pathways that control gut barrier functions. Amidst expanding technology and broadening knowledge, exploitation of beneficial microbiota and their metabolites to restore pathophysiological balance will likely prove to be an extremely useful remedial tool.

Chronic Inflammatory Diseases, Anti-Inflammatory Agents and Their Delivery Nanosystems

Inflammatory diseases, whether caused by excessive stress on certain tissues/parts of the body or arising from infections accompanying autoimmune or secondary diseases, have become a problem, especially in the Western world today. Whether these are inflammations of visceral organs, joints, bones, or the like, they are always a physiological reaction of the body, which always tries to eradicate noxious agents and restore tissue homeostasis. Unfortunately, this often results in damage, often irreversible, to the affected tissues. Nevertheless, these inflammatory reactions of the body are the results of excessive stress, strain, and the generally unhealthy environment, in which the people of Western civilization live. The pathophysiology and pathobiochemistry of inflammatory/autoimmune processes are being studied in deep detail, and pharmaceutical companies are constantly developing new drugs that modulate/suppress inflammatory responses and endogenous pro-inflammatory agents. In addition to new specifically targeted drugs for a variety of pro-inflammatory agents, a strategy can be found for the use of older drugs, which are formulated into special nanodrug delivery systems with targeted distribution and often modified release. This contribution summarizes the current state of research and development of nanoformulated anti-inflammatory agents from both conventional drug classes and experimental drugs or dietary supplements used to alleviate inflammatory reactions.

Ultraperformance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Mass Spectrometry-Based Metabolomics and Lipidomics Identify Biomarkers for Efficacy Evaluation of Mesalazine in a Dextran Sulfate Sodium-Induced Ulcerative Colitis Mouse Model

This study aims to identify biomarkers for evaluating the therapeutic efficacy of mesalazine on ulcerative colitis by metabolomics and lipidomics. A dextran sulfate sodium-induced mouse model was used. The disease status was assessed by a disease activity index, the TNF-α level of colon was measured by an enzyme-linked immunosorbent assay, and the pathological changes of colon tissue was examined by hematoxylin-eosin staining. Serum metabolomics and lipidomics analysis based on ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry were applied to decipher the metabolic profile changes. Multivariate analysis was applied to differentiate the metabolites of controls, models, and mesalazine-treated mice. By the receiver operating characteristic (ROC) analysis, 40 differential metabolites with an area under curve (AUC) >0.80 were screened out between control and model groups. Among them, four potential biomarkers (palmitoyl glucuronide, isobutyrylglycine, PC (20:3 (5Z, 8Z, 11Z)/15:0) and L-arginine) had a signficantly reversed level of peak areas in the mesalazine group, and three of them were closely correlated with mesalazine efficacy by linear regression analysis. Furthermore, metabolic pathway analysis revealed several dysregulated pathways in colitis mice, including glycerophospholipid metabolism, pyrimidine metabolism, linoleic acid metabolism, arginine biosynthesis, etc. This study indicates that serum metabolomics is a useful approach that can noninvasively evaluate the therapeutic effect and provide unique insights into the underlying mechanism of mesalazine.

The Polyphosphate Kinase of Escherichia coli Is Required for Full Production of the Genotoxin Colibactin

Colibactin induces DNA damage in mammalian cells and has been linked to the virulence of Escherichia coli and the promotion of colorectal cancer (CRC). By looking for mutants attenuated in the promoter activity of clbB encoding one of the key enzymes for the production of colibactin, we found that a mutant of the gene coding for the polyphosphate kinase (PPK) produced less colibactin than the parental strain. We observed this phenotype in different strains ranging from pathogens responsible for meningitis, urinary tract infection, or mouse colon carcinogenesis to the probiotic Nissle 1917. We confirmed the role of PPK by using an inhibitor of PPK enzymatic activity, mesalamine (also known as 5-aminosalicylic acid). Interestingly, mesalamine has a local anti-inflammatory effect on the epithelial cells of the colon and is used to treat inflammatory bowel disease (IBD). Upon treatment with mesalamine, a decreased genotoxicity of colibactin-producing E. coli was observed both on epithelial cells and directly on purified DNA. This demonstrates the direct effect of mesalamine on bacteria independently from its anti-inflammatory effect on eukaryotic cells. Our results suggest that the mechanisms of action of mesalamine in treating IBD and preventing CRC could also lie in the inhibition of colibactin production. All in all, we demonstrate that PPK is required for the promoter activity of clbB and the production of colibactin, which suggests that PPK is a promising target for the development of anticolibactin and antivirulence strategies.IMPORTANCE Colibactin-producing E. coli induces DNA damage in eukaryotic cells and promotes tumor formation in mouse models of intestinal inflammation. Recent studies have provided strong evidence supporting the causative role of colibactin in human colorectal cancer (CRC) progression. Therefore, it is important to understand the regulation of the production of this genotoxin. Here, we demonstrate that polyphosphate kinase (PPK) is required for the promoter activity of clbB and the production of colibactin. Interestingly, PPK is a multifunctional player in bacterial virulence and stress responses and has been proposed as a new target for developing antimicrobial medicine. We observed inhibition of colibactin production by using a previously identified PPK inhibitor (i.e., mesalamine, an anti-inflammatory drug commonly prescribed for inflammatory bowel diseases). These data brought us a new perspective on the regulatory network of colibactin production and provided us a clue for the development of anticolibactin strategies for CRC treatment/prophylaxis.

A Novel PAK1-Notch1 Axis Regulates Crypt Homeostasis in Intestinal Inflammation

BACKGROUND & AIMS

p21-activated kinase-1 (PAK1) belongs to a family of serine-threonine kinases and contributes to cellular pathways such as nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), and Wingless-related integration site(Wnt)/β-catenin, all of which are involved in intestinal homeostasis. Overexpression of PAK1 is linked to inflammatory bowel disease as well as colitis-associated cancer (CAC), and similarly was observed in interleukin (IL)10 knockout (KO) mice, a model of colitis and CAC. Here, we tested the effects of PAK1 deletion on intestinal inflammation and carcinogenesis in IL10 KO mice.

METHODS

IL10/PAK1 double-knockout (DKO) mice were generated and development of colitis and CAC was analyzed. Large intestines were measured and prepared for histology or RNA isolation. Swiss rolls were stained with H&E and periodic acid-Schiff. Co-immunoprecipitation and immunofluorescence were performed using intestinal organoids, SW480, and normal human colon epithelial cells 1CT.

RESULTS

When compared with IL10 KO mice, DKOs showed longer colons and prolonged crypts, despite having higher inflammation and numbers of dysplasia. Crypt hyperproliferation was associated with Notch1 activation and diminished crypt differentiation, indicated by a reduction of goblet cells. Gene expression analysis indicated up-regulation of the Notch1 target hairy and enhancer of split-1 and the stem cell receptor leucin-rich repeat-containing G-protein-coupled receptor 5 in DKO mice. Interestingly, the stem cell marker olfactomedin-4 was present in colonic tissue. Increased β-catenin messenger RNA and cytoplasmic accumulation indicated aberrant Wnt signaling. Co-localization and direct interaction of Notch1 and PAK1 was found in colon epithelial cells. Notch1 activation abrogated this effect whereas silencing of PAK1 led to Notch1 activation.

CONCLUSIONS

PAK1 contributes to the regulation of crypt homeostasis under inflammatory conditions by controlling Notch1. This identifies a novel PAK1-Notch1 axis in intestinal pathophysiology of inflammatory bowel disease and CAC.

Safranal Alleviates Dextran Sulfate Sodium-Induced Colitis and Suppresses Macrophage-Mediated Inflammation

Introduction:Crocus sativus (saffron) is widely used in China, Iran, and India for dyeing and as a food additive and medicinal plant. Safranal, as one of the main constituents of saffron, is responsible for its aroma and has been reported to have anticancer, antioxidant, and anti-inflammation properties.

Objective: In this study, we investigated the anti-inflammatory effects of Safranal in RAW264.7 cells, bone marrow-derived macrophages (BMDMs), and dextran sulfate sodium (DSS)-induced colitis mice.

Methods: Safranal toxicity was determined using an MTT assay. We evaluated the inhibitory effect of nitric oxide (NO) and levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in RAW264.7 cells and BMDMs. We assessed the inhibitory effect of pro-inflammatory cytokines, and the mRNA expressions of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), classical inflammatory pathways (MAPK and NF-κB), and the nuclear translocation factors AP-1 and NF-κB p65 were investigated. The in vivo anti-inflammatory effects of Safranal were assessed in a DSS-induced colitis model. DSS3.5% was used to induce colitis in mice with or without Safranal for 7 days; weight and disease activity index (DAI) were recorded daily. At the end of the experiment, the colon, mesenteric lymph nodes (MLNs), and spleen were collected for flow cytometry, ELISA, and Western blot analysis.

Results: Safranal suppressed NO production, iNOS, and COX-2 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and BMDMs. Safranal decreased the production and mRNA expression of IL-6 and TNF-α in the RAW264.7 cell line and inhibited the phosphorylation and nuclear translocation of components of the MAPK and NF-κB pathways. Safranal alleviated clinical symptoms in the DSS-induced colitis model, and colon histology showed decreased severity of inflammation, depth of inflammatory involvement, and crypt damage. Immunohistochemical staining and flow cytometry showed reduced macrophage infiltration in colonic tissues and macrophage numbers in MLNs and the spleen. The levels of colonic IL-6 and TNF-α also decreased in Safranal-treated colitis mice. This study elucidates the anti-inflammation activity of Safranal, which may be a candidate for inflammatory bowel syndrome (IBD) therapy.

A Direct Effect of Sex Hormones on Epithelial Barrier Function in Inflammatory Bowel Disease Models

BACKGROUND

Pregnancy is often described as an immune-tolerant state, and a disease modulatory role for pregnancy on inflammatory bowel disease (IBD) has been suggested. The direct effect of estrogen and progesterone on the intestinal epithelial barrier is underexplored. We investigated the direct consequences of these pregnancy hormones on barrier cells and their function.

METHODS

We used IBD patient-derived inflammatory organoid models and 2D cell lines models. Epithelial barrier function was analyzed by measuring transepithelial electrical resistance; wound closure was determined by scratch assay; and cell viability was measured by MTT assays. Pro-inflammatory cytokine production was determined by enzyme-linked immunosorbent assays. Molecular modulation of endoplasmic reticulum (ER) stress induced by tunicamycin was studied by western blot analysis of the ER stress markers GRP78, CHOP and p-IRE1.

RESULTS

Progesterone and estrogen improved wound healing and epithelial barrier function in intestinal epithelial cells via upregulation of tight junction proteins. Furthermore, these sex hormones significantly reduced ER-stress and reduce pro-inflammatory cytokine production in intestinal epithelial models.

CONCLUSION

Our study shows that estrogen and progesterone alleviate ER stress, decrease pro-inflammatory cytokine production, stimulate wound healing, and increase barrier function of epithelial cells. Combined, these data suggest that pregnancy hormones can have beneficial effects on disease activity by positively modulating the intestinal epithelial lining.