Including Inflammatory Bowel Disease Research Articles

The Role of TRP Channels in Sepsis and Colitis.

To date, several members of the transient receptor potential (TRP) channels which provide a wide array of roles have been found in the gastrointestinal tract (GI). The goal of earlier research was to comprehend the intricate signaling cascades that contribute to TRP channel activation as well as how these receptors' activity affects other systems. Moreover, there is a large volume of published studies describing the role of TRP channels in a number of pathological disorders, including inflammatory bowel disease (IBD) and sepsis. Nevertheless, the generalizability of these results is subject to certain limitations. For instance, the study of IBD relies on various animal models and experimental methods, which are unable to precisely imitate the multifactorial chronic disease. The diverse pathophysiological mechanisms and unique susceptibility of animals may account for the inconsistency of the experimental data collected. The main purpose of this study was to conduct a comprehensive review and analysis of existing studies on transient receptor potential (TRP) channels implicating specific models of colitis and sepsis, with particular emphasis on their involvement in pathological disorders such as IBD and sepsis. Furthermore, the text endeavors to evaluate the generalizability of experimental findings, taking into consideration the limitations posed by animal models and experimental methodologies. Finally, we also provide an updated schematic of the most important and possible molecular signaling pathways associated with TRP channels in IBD and sepsis.

Intestinal Fibrogenesis in Inflammatory Bowel Diseases: Exploring the Potential Role of Gut Microbiota Metabolites as Modulators.

Fibrosis, sustained by the transformation of intestinal epithelial cells into fibroblasts (epithelial-to-mesenchymal transition, EMT), has been extensively studied in recent decades, with the molecular basis well-documented in various diseases, including inflammatory bowel diseases (IBDs). However, the factors influencing these pathways remain unclear. In recent years, the role of the gut microbiota in health and disease has garnered significant attention. Evidence suggests that an imbalanced or dysregulated microbiota, along with environmental and genetic factors, may contribute to the development of IBDs. Notably, microbes produce various metabolites that interact with host receptors and associated signaling pathways, influencing physiological and pathological changes. This review aims to present recent evidence highlighting the emerging role of the most studied metabolites as potential modulators of molecular pathways implicated in intestinal fibrosis and EMT in IBDs. These studies provide a deeper understanding of intestinal inflammation and fibrosis, elucidating the molecular basis of the microbiota role in IBDs, paving the way for future treatments.

The effect of novel paraprobiotic cocktail on dextran sodium sulfate induced acute colitis control focusing on autophagy signaling pathway.

Paraprobiotics are a non-viable form of probiotics that are reported to provide significant health benefits. Nevertheless, little is known about the beneficial effects of paraprobiotics on inflammatory bowel disease. Although probiotics show potential as therapeutic agents for a range of diseases, including inflammatory bowel disease (IBD), there are certain risks associated with their use. These risks include toxin production, hemolytic potential, antibiotic resistance, and the need to analyze metabolic activities. Hence Using paraprobiotic with the lower aforementioned risk would therefore be the preferable option. Here, we conducted an in vivo study to evaluate the preventive effect of our native paraprobiotic cocktail against dextran sulfate sodium (DSS)-induced murine colitis by affecting the autophagy signaling pathway. Four-week-old male C57Bl/6 mice were randomly divided into three groups after a two-week acclimation period with normal standard laboratory food diet. Mice were administered PBS (PBS group as control), PBS along with DSS (DSS group, as a control), and a cocktail of paraprobiotics along with DSS (Para group). The severity of colitis, length and histopathology of the colon were evaluated. In addition, the expression of autophagy was assessed using real-time PCR. The results showed that administration of the paraprobiotic cocktail to DSS-treated mice inhibited the severity of colitis symptoms, as evidenced by the inhibition of weight loss and DAI, as well as histopathological scores in the study colon, as well as shortening of colon length caused by DSS. In contrast to the DSS group, the cocktail was able to modulate inflammation through upregulation of autophagy-related genes (becline 1, atg5, atg7, atg12, and atg13). Although there are some limitations in our investigation, such as the dosage and duration of treatments, our native paraprobiotic blend effectively prevented the advancement of colitis. This suggests that it plays a vital role in regulating inflammation and preventing colitis by promoting the autophagy mechanism in cases where the consumption of probiotics may have negative consequences.

Krill Oil and Its Bioactive Components as a Potential Therapy for Inflammatory Bowel Disease: Insights from In Vivo and In Vitro Studies.

Krill oil is extracted from krill, a small crustacean in the Antarctic Ocean. It has received growing attention because of krill oil's unique properties and diverse health benefits. Recent experimental and clinical studies suggest that it has potential therapeutic benefits in preventing the development of a range of chronic conditions, including inflammatory bowel disease (IBD). Krill oil is enriched with long-chain n-3 polyunsaturated fatty acids, especially eicosapentaenoic and docosahexaenoic acids, and the potent antioxidant astaxanthin, contributing to its therapeutic properties. The possible underlying mechanisms of krill oil's health benefits include anti-inflammatory and antioxidant actions, maintaining intestinal barrier functions, and modulating gut microbiota. This review aims to provide an overview of the beneficial effects of krill oil and its bioactive components on intestinal inflammation and to discuss the findings on the molecular mechanisms associated with the role of krill oil in IBD prevention and treatment.

Oral pathobiont Klebsiella chaperon usher pili provide site-specific adaptation for the inflamed gut mucosa

ABSTRACT The ectopic gut colonization by orally derived pathobionts has been implicated in the pathogenesis of various gastrointestinal diseases, including inflammatory bowel disease (IBD). For example, gut colonization by orally derived Klebsiella spp. has been linked to IBD in mice and humans. However, the mechanisms whereby oral pathobionts colonize extra-oral niches, such as the gut mucosa, remain largely unknown. Here, we performed a high-density transposon (Tn) screening to identify genes required for the adaptation of an oral Klebsiella strain to different mucosal sites – the oral and gut mucosae – at the steady state and during inflammation. We find that K. aerogenes, an oral pathobiont associated with both oral and gut inflammation in mice, harbors a newly identified genomic locus named “locus of colonization in the inflamed gut (LIG)” that encodes genes related to iron acquisition (Sit and Chu) and host adhesion (chaperon usher pili [CUP] system). The LIG locus is highly conserved among K. aerogenes strains, and these genes are also present in several other Klebsiella species. The Tn screening revealed that the LIG locus is required for the adaptation of K. aerogenes in its ectopic niche. In particular, we determined K. aerogenes employs a CUP system (CUP1) present in the LIG locus for colonization in the inflamed gut, but not in the oral mucosa. Thus, oral pathobionts likely exploit distinct adaptation mechanisms in their ectopically colonized intestinal niche compared to their native niche.

Abstract 5636: CUX1 transcriptionally regulates intestinal epithelial homeostasis

Abstract The small intestine digests and absorbs nutrients, a role made possible by specialized secretory and absorptive cells that constantly replenish from the intestinal stem cell niche. Disruption in intestinal epithelium homeostasis has been linked to pathologies including inflammatory bowel disease (IBD) and cancer. However, the processes regulating differentiation in healthy and disease setting are incompletely understood. CUX1 is a highly conserved homeodomain-containing transcription factor that is expressed in small intestinal crypts and has been previously shown to be essential in mice and Drosophila. CUX1 is upregulated upon inflammatory stress conditions, including intestinal damage and in IBD. In addition, CUX1 is predicted to be protective against IBD from genome-wide association studies. The aim of the current work is to determine the mechanistic role of CUX1 in secretory intestinal cells differentiation and epithelial homeostasis. To this end, we have generated transgenic mouse models that modulate CUX1 levels in an inducible manner. Mice with near-null CUX1 levels exhibit rapid weight loss requiring euthanasia while mice with ~50% residual CUX1 halt normal weight gain. Histologic examination of tissues from mice with CUX1 knock-down reveals a lack of mature secretory cells, including goblet and Paneth cells, the latter playing a supportive role to intestinal stem cells. Moreover, mouse intestinal tissues from our knock-down models demonstrated decreased proliferation with increased apoptosis. In transcriptome profiling, we observed downregulation of proliferation, intestinal stem cell, and digestive system developmental gene signatures and decreased levels of key secretory cell regulators, pointing towards a role for CUX1 in stem cell maintenance and differentiation. Indeed, reducing CUX1 levels decreased β-catenin protein levels, while Wnt/β-catenin signaling is required for the organization of the crypt-villus axis. Finally, CUX1 knock-down compromises the ability to form budding organoids, demonstrating the cell intrinsic role for CUX1 in stem cell differentiation. In ongoing studies, we are identifying CUX1 genome-wide binding targets and the epigenetic impact of CUX1 in intestinal epithelium cells. Our findings indicate that CUX1 is a critical regulator of intestinal epithelium homeostasis that has a role in differentiation and potential role in injury-induced de-differentiation in healthy as well as IBD patients. We propose that CUX1 regulates stem cell maintenance and crypt composition by regulating Wnt/β-catenin signaling and inducing fetal-like transcriptomic repair program shown to be coopted by colon cancers. Resolving an intricate network of transcriptional regulation of differentiation in the intestinal crypt holds the potential to successfully target inflammation-related damage in human intestines. Citation Format: Katarzyna Zawieracz, Ningfei An, Megan McNerney. CUX1 transcriptionally regulates intestinal epithelial homeostasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5636.

A systematic review of the efficacy and safety of turmeric in the treatment of digestive disorders.

Turmeric has been gaining popularity as a treatment option for digestive disorders, although a rigorous synthesis of efficacy has not been conducted. This study aimed to summarize the evidence for the efficacy and safety of turmeric in the treatment of digestive disorders, including inflammatory bowel diseases (IBD), irritable bowel syndrome (IBS), dyspepsia, gastroesophageal reflux disease, and peptic ulcers. Literature searches were conducted in Medline, EMBASE, AMED, the Cochrane Central Register of Control Trials, and Dissertation Abstracts from inception to November 15, 2021. Dual independent screening of citations and full texts was conducted and studies meeting inclusion criteria were retained: randomized controlled trials (RCT) and comparative observational studies evaluating turmeric use in people of any age with one of the digestive disorders of interest. Extraction of relevant data and risk of bias assessments were performed by two reviewers independently. Meta-analysis was not conducted due to high heterogeneity. From 1136 citations screened, 26 eligible studies were retained. Most studies were assessed to have a high risk of bias, and many had methodological limitations. Descriptive summaries suggest that turmeric is safe, with possible efficacy in patients with IBD or IBS, but its effects were inconsistent for other conditions. The efficacy of turmeric in digestive disorders remains unclear due to the high risk of bias and methodological limitations of the included studies. Future studies should be designed to include larger sample sizes, use rigorous statistical methods, employ core outcome sets, and adhere to reporting guidance for RCTs of herbal interventions to facilitate more meaningful comparisons and robust conclusions.

PH-responsive interface conversion efficient oral drug delivery platform for alleviating inflammatory bowel disease.

A key challenge for the effective treatment of intestinal diseases, including inflammatory bowel disease (IBD), is to develop an oral drug delivery system that can resist gastric acid erosion and efficiently release drugs after rapid entry into the intestine. In the present work, we developed oral composite nanoparticles (MSZ@PRHS) consisting of a rough mesoporous silica (RHS) loaded with Mesalazine (MSZ) and a CAP polymer membrane for targeted relief of inflammation in colitis. At the pH values of the simulated stomach and small intestine, the release rate of MSZ from MSZ@PRHS was low, while at the pH values of the simulated colon, the release rate of MSZ was high. In dextran sulfate sodium salt (DSS)-induced acute colitis mouse model, compared with oral administration of the drug Mesalazine in the equivalent solution form, oral administration of PRHS loaded with drug-loaded nanoparticles can significantly alleviate the symptoms of inflammatory bowel disease, and improve the therapeutic effect. We propose that the intestinal microenvironment provides an interface for nanocomposites switch and a promising drug delivery platform for the management and treatment of many intestinal diseases, where controlled drug release and prolonged residence time are required.

The Role of Anthocyanins in Alleviating Intestinal Diseases: A Mini Review.

Anthocyanins are phytonutrients with physiological activity belonging to the flavonoid family whose transport and absorption in the human body follow specific pathways. In the upper gastrointestinal tract, anthocyanins are rarely absorbed intact by active transporters, with most reaching the colon, where bacteria convert them into metabolites. There is mounting evidence that anthocyanins can be used for prevention and treatment of intestinal diseases, including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and colorectal cancer (CRC), through the protective function on the intestinal epithelial barrier, immunomodulation, antioxidants, and gut microbiota metabolism. Dietary anthocyanins are summarized in this comprehensive review with respect to their classification and structure as well as their absorption and transport mechanisms within the gastrointestinal tract. Additionally, the review delves into the role and mechanism of anthocyanins in treating common intestinal diseases. These insights will deepen our understanding of the potential benefits of natural anthocyanins for intestinal disorders.

An Update on the Role and Potential Molecules in Relation to Ruminococcus gnavus in Inflammatory Bowel Disease, Obesity and Diabetes Mellitus.

Ruminococcus gnavus (R. gnavus) is a gram-positive anaerobe commonly resides in the human gut microbiota. The advent of metagenomics has linked R. gnavus with various diseases, including inflammatory bowel disease (IBD), obesity, and diabetes mellitus (DM), which has become a growing area of investigation. The initial focus of research primarily centered on assessing the abundance of R. gnavus and its potential association with disease presentation, taking into account variations in sample size, sequencing and analysis methods. However, recent investigations have shifted towards elucidating the underlying mechanistic pathways through which R. gnavus may contribute to disease manifestation. In this comprehensive review, we aim to provide an updated synthesis of the current literature on R. gnavus in the context of IBD, obesity, and DM. We critically analyze relevant studies and summarize the potential molecular mediators implicated in the association between R. gnavus and these diseases. Across numerous studies, various molecules such as methylation-controlled J (MCJ), glucopolysaccharides, ursodeoxycholic acid (UDCA), interleukin(IL)-10, IL-17, and capric acid have been proposed as potential contributors to the link between R. gnavus and IBD. Similarly, in the realm of obesity, molecules such as hydrogen peroxide, butyrate, and UDCA have been suggested as potential mediators, while glycine ursodeoxycholic acid (GUDCA) has been implicated in the connection between R. gnavus and DM. Furthermore, it is imperative to emphasize the necessity for additional studies to evaluate the potential efficacy of targeting pathways associated with R. gnavus as a viable strategy for managing these diseases. These findings have significantly expanded our understanding of the functional role of R. gnavus in the context of IBD, obesity, and DM. This review aims to offer updated insights into the role and potential mechanisms of R. gnavus, as well as potential strategies for the treatment of these diseases.

Ectopic colonization by oral bacteria as an emerging theme in health and disease.

The number of research papers published on the involvement of the oral microbiota in systemic diseases has grown exponentially over the last 4 years clearly demonstrating the growing interest in this field. Indeed, accumulating evidence highlights the central role of ectopic colonization by oral bacteria in numerous noncommunicable diseases including inflammatory bowel diseases (IBDs), undernutrition, preterm birth, neurological diseases, liver diseases, lung diseases, heart diseases, or colonic cancer. There is thus much interest in understanding the molecular mechanisms that lead to the colonization and maintenance of ectopic oral bacteria. The aim of this review is to summarize and conceptualize the current knowledge about ectopic colonization by oral bacteria, highlight wherever possible the underlying molecular mechanisms and describe its implication in health and disease. The focus lies on the newly discovered molecular mechanisms, showcasing shared pathophysiological mechanisms across different body sites and syndromes and highlighting open questions in the field regarding the pathway from oral microbiota dysbiosis to noncommunicable diseases.

AMBRA1 promotes intestinal inflammation by antagonizing PP4R1/PP4c mediated IKK dephosphorylation in an autophagy-independent manner.

IκB kinase (IKK) complex is central regulators of the NF-κB pathway, and dysregulation of IKK phosphorylation leads to hyperactivation of proinflammatory response in various chronic inflammatory diseases, including inflammatory bowel disease (IBD). However, the dynamic modulation of IKK phosphorylation and dephosphorylation in intestinal inflammation remains uncharacterized. Here, we found that autophagy/beclin-1 regulator 1 (AMBRA1) was highly expressed in inflamed colons in a colitis mouse model and in clinical IBD samples. Importantly, AMBRA1 deletion significantly decreased proinflammatory cytokine expression and enhanced the therapeutic effect of infliximab on intestinal inflammation. Mechanistically, the N-term F1 domain of AMBRA1 was required for AMBRA1 to competitively interact with protein phosphatase 4 regulatory subunit 1 (PP4R1) and catalytic protein phosphatase 4 (PP4c) to suppress their interactions with IKK, promote the dissociation of the PP4R1/PP4c complex, and antagonize the dephosphorylation activity of this complex towards the IKK complex. In response to TNF-α stimulation, IKKα phosphorylates AMBRA1 at S1043 to stabilize AMBRA1 expression by impairing its binding to Cullin4A (CUL4A) to decrease its CUL4A-mediated K48-linked ubiquitination. Overall, our study identifies an autophagy-independent function of AMBRA1 as a positive modulator of IKK phosphorylation to promote intestinal inflammation, thus providing a new targeted therapeutic strategy for patients with refractory IBD.

Discovery of a Highly Potent Oxysterol Receptor GPR183 Antagonist Bearing the Benzo[d]thiazole Structural Motif for the Treatment of Inflammatory Bowel Disease (IBD).

Accumulating evidence has demonstrated a critical pathological role of oxysterol receptor GPR183 in various inflammatory and autoimmune diseases, including inflammatory bowel disease (IBD). However, the currently reported GPR183 antagonists are very limited and not qualified for in vivo studies due to their inferior druglike properties. Herein, we conducted a structural elaboration focusing on improving its PK and safety profile based on a reference antagonist NIBR189. Of note, compound 33, bearing an aminobenzothiazole motif, exhibited reduced hERG inhibition, improved PK properties, and robust antagonistic activity (IC50 = 0.82 nM) with high selectivity against GPR183. Moreover, compound 33 displayed strong in vitro antimigration and anti-inflammatory activity in monocytes. Oral administration of compound 33 effectively improved the pathological symptoms of DSS-induced experimental colitis. All of these findings demonstrate that compound 33 is a novel and promising GPR183 antagonist suitable for further investigation to treat IBD.

A5 DEVELOPMENT OF A PRE-CLINICAL MOUSE MODEL TO INVESTIGATE ADVERSE FOOD REACTIONS IN INTESTINAL INFLAMMATION

Abstract Background Patients with chronic intestinal conditions, including inflammatory bowel disease (IBD), experience diverse food-related adverse reactions. However,, the precise mechanisms of food intolerances in IBD remains unclear. Emerging evidence suggests that altered diet-microbiota interactions can contribute to the development of IBD. Previously we shown that intestinal microbiota plays an important role in the development of food intolerances. We hypothesize that microbial alterations in IBD patients facilitate adverse reactions to foods. Aims To establish a preclinical mouse model to study adverse food reactions in intestinal inflammation. Methods Eight-week-old C57BL/6 mice were treated with 3% dextran sodium sulfate (DSS) for 5 days, then divided into three groups. The first group was sensitized to dairy protein (3% casein and 3% whey), using 4 oral administrations of cholera toxin over 2 weeks, without any further diet intervention. The second group was also sensitized to casein and whey, then after 1 week of recovery, the mice were subsequently place on a chow containing casein and whey. Finally, the third group was subjected to diet intervention without sensitization. The same experiment was repeated in a different subset of C57BL/6 mice which included a second cycle of DSS (1.5%) during the dietary interventions. Markers of intestinal inflammation (disease activity index (DAI), histological damage, cell infiltration and pro-inflammatory genes expression (NanoString)) and intestinal microbiota were analysed after 1 week of the diet intervention. Results Mice previously sensitized on the dairy diet exhibited an enhanced activation of immune cells after intestinal inflammation. While the histological damage score did not reveal significant differences among experimental groups, the sensitized group under dairy intervention exhibited an elevated level of immune cell infiltration, increasing the polymorphonuclear, CD3+ and mast cells. Gene expression also revealed that dairy induced the expression of inflammatory genes, such as C6, Arg1, Tnf, Il6, Cxcl9 and Cxcl10. When animals are subjected to a second DSS-cycle, dairy worsen colitis in mice previously sensitized, as shown by higher DAI compared to group with control diet and dairy diet without sensitization. Conclusions In the context of intestinal inflammation, dairy protein leads to immune activation characterized by an increase in polymorphonuclear cells, mast cells and lymphocytes, as well as worsening colitis. Future studies using this model will provide valuable insights into the role of intestinal microbiota in food intolerances associated with intestinal inflammation. Funding Agencies CCC

The Role of Methanogenic Archaea in Inflammatory Bowel Disease-A Review.

Methanogenic archaea are a part of the commensal gut microbiota responsible for hydrogen sink and the efficient production of short-chain fatty acids. Dysbiosis of methanogens is suspected to play a role in pathogenesis of variety of diseases, including inflammatory bowel disease (IBD). Unlike bacteria, the diversity of archaea seems to be higher in IBD patients compared to healthy subjects, whereas the prevalence and abundance of gut methanogens declines in IBD, especially in ulcerative colitis. To date, studies focusing on methanogens in pediatric IBD are very limited; nevertheless, the preliminary results provide some evidence that methanogens may be influenced by the chronic inflammatory process in IBD. In this review, we demonstrated the development and diversity of the methanogenic community in IBD, both in adults and children.

5S-Heudelotinone alleviates experimental colitis by shaping the immune system and enhancing the intestinal barrier in a gut microbiota-dependent manner

Aberrant changes in the gut microbiota are implicated in many diseases, including inflammatory bowel disease (IBD). Gut microbes produce diverse metabolites that can shape the immune system and impact the intestinal barrier integrity, indicating that microbe-mediated modulation may be a promising strategy for preventing and treating IBD. Although fecal microbiota transplantation and probiotic supplementation are well-established IBD therapies, novel chemical agents that are safe and exert strong effects on the gut microbiota are urgently needed. Herein, we report the total synthesis of heudelotinone and the discovery of 5S-heudelotinone (an enantiomer) as a potent agent against experimental colitis that acts by modulating the gut microbiota. 5S-Heudelotinone alters the diversity and composition of the gut microbiota and increases the concentration of short-chain fatty acids (SCFAs); thus, it regulates the intestinal immune system by reducing proinflammatory immune cell numbers, and maintains intestinal mucosal integrity by modulating tight junctions (TJs). Moreover, 5S-heudelotinone (2) ameliorates colitis-associated colorectal cancer (CAC) in an azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced in situ carcinoma model. Together, these findings reveal the potential of a novel natural product, namely, 5S-heudelotinone, to control intestinal inflammation and highlight that this product is a safe and effective candidate for the treatment of IBD and CAC.

3D MORPHOGENESIS AND BACTERIAL CO-CULTURE IN A CANINE GUT-ON-A-CHIP USING BIOPSY-DERIVED INTESTINAL ORGANOIDS FROM HEALTHY AND IBD PATIENTS

Abstract The understanding of the role of intestinal bacteria in various intestinal diseases has been limited due to the lack of suitable in vitro models. However, recent advancements in Gut-on-a-Chip culture technology provide a promising avenue for exploring complex interactions between intestinal epithelium and bacteria. In this study, we aimed to create a microfluidic Gut-on-a-Chip co-culture system using dogs as a model. Dogs share similarities with humans in terms of intestinal disease pathophysiology, clinical presentations, and intestinal microbiome, making them a relevant model for various intestinal diseases, including inflammatory bowel disease (IBD). We cultured colonoids from both healthy dogs and dogs with IBD on the Gut-on-a-Chip platform to create villus-like structures under dynamic conditions. Co-cultures with non-pathogenic Escherichia coli (NPE) were established in the Gut-on-a-Chip with healthy colonoids, and we conducted a static Transwell (TW) co-culture for comparison. To assess epithelial barrier integrity, we measured transepithelial electrical resistance (TEER), and we evaluated the expression of ZO-1, a tight junction protein, through immunofluorescence staining (IF). Following 6-9 days of uninterrupted medium flow in the Gut-on-a-Chip models, we observed sporadic clusters of villus-like structures (i.e., 3D morphogenesis) in canine intestinal epithelial cells in both the models derived from healthy dogs and those with IBD. The IF confirmed the presence of ZO-1, indicating the establishment of tight junctions. Infection with NPE in the TW system resulted in a significant reduction in TEER (48.2±4.4% at 12 hours and 7.3±5.3% at 24 hours). In contrast, the Gut-on-a-Chip maintained TEER levels at 100.3±12.8% at 12 hours, 94.9±2.2% at 24 hours, and 88.8±15.0% at 48 hours, preserving the 3D structure. The innovative canine Gut-on-a-Chip model, capable of reproducing villus-like structures and preserving a 3D configuration using both healthy and diseased organoids (specifically, IBD), presents a valuable platform for investigating bacterial-epithelium interactions in both human and veterinary medicine. This dynamic microfluidic culture system enables the co-cultivation of living bacteria while maintaining epithelial integrity, facilitating the study of intricate interactions between intestinal bacteria and epithelial crosstalk.

CD11B/CD18 SIALYLATION REGULATES NEUTROPHIL TRAFFICKING AND INFLAMMATORY FUNCTION IN THE INTESTINE

Abstract Pathogen-triggered neutrophil (PMN) recruitment is critical for innate immunity, but excessive PMN influx and associated mucosal tissue damage is implicated in the pathogenesis of numerous human inflammatory disorders including inflammatory bowel disease (IBD). Critically in both ulcerative colitis and Crohn’s disease, disease flares requiring medical intervention are associated with migration of large numbers of PMNs across colonic epithelium resulting in mucosal injury/ulceration. Recent studies have shown that specific PMN glycans can be targeted to reduce transepithelial migration (TEpM) the critical final step in PMN intestinal trafficking. However the role of Sialic acid (Sia), the most abundant PMN expressed terminal glycan, in regulating PMN migration and inflammatory function in the gut is not well understood. Using sophisticated models of human and murine PMN intestinal migration, we show that blocking sialidase-mediated removal of alpha 2-3 linked sialic acid from CD11b/CD18 inhibits PMN TEpM in vitro and in vivo.Measurement of cytochrome C reduction revealed that inhibition of sialidases reduced bacterial peptide (fMLF) stimulated superoxide release by human and murine PMN. Flow cytometry analyses revealed that sialidase inhibition decreased fMLF mediated PMN degranulation and fMLF mediated CD11b/CD18 conformational activation. Highlighting the functional importance of individual Sia residues, inhibition of alpha 2-3 sialidase activity with 3’ Sialyllactose (3’SL) was found to inhibit PMN intestinal trafficking in vitro and in vivo and reduce PMN degranulation responses. Immunoblotting studies showed that sialidase inhibition deactivates spleen tyrosine kinase (Syk) and p38 MAP kinase, key intracellular mediators that signal downstream of PMN CD11b/CD18. Finally, inhibition of sialidase activity reduced adhesion of PMN to ICAM-1 (a major physiological substrate of CD11b/CD18) demonstrating that endogenous PMN sialidases regulate binding interactions between migrating PMN and intestinal epithelial receptors. Taken together data show that upon activation PMN sialidases remove alpha 2-3 Sia from CD11b/CD18 which leads to integrin activation and subsequent outside in signaling mediated by Syk to drive PMN inflammatory effector functions including migration, degranulation, and superoxide release. As such targeting CD11b/CD18 sialylation represents a promising new therapeutic strategy for reducing dysregulated PMN influx and associated mucosal tissue damage in IBD and other inflammatory disorders.

STERILE NEUTROPHILIA INDUCED VIA CXCR4 ANTAGONISM MITIGATES COLONIC INFLAMMATION BY ENHANCING IMMUNOSUPPRESSIVE REGULATORY T CELLS IN MICE

Abstract Sterile neutrophilia (SN) is commonly associated with chronic diseases including inflammatory bowel diseases (IBD), but its defined role is largely unknown. Plerixafor (AMD3100) is a CXCR4 antagonist that promotes neutrophil egress from bone marrow resulting in SN. We first confirmed that C57BL6/J mice administered Plerixafor (10 mg/kg/bw, i.p.,) increased their circulating neutrophils by 50% within 2.5 h. Further, to study the role of SN in IBD, we induced chronic colitis by neutralizing IL-10 signaling via αIL-10R mAb (1.0 mg/mouse, i.p., 4 weekly injections) with or without weekly twice Plerixafor. Control mice were given isotype control mAb. As expected, αIL-10R+Plerixafor-treated mice had increased peripheral and splenic neutrophils. Further, these mice displayed remarkably reduced epithelial damage, hyperplasia, immune cell infiltration, and disease activity index when compared to αIL-10R+vehicle treated mice, which had typical colitis symptoms. To delineate the mechanism for such protection by Plerixafor, we profiled immune cells in circulation, spleen and lamina propria. In circulation αIL-10R+Plerixafor-treated mice had elevated CD3+CD4+ helper T cells (Th) but reduced CD3+CD8+ cytotoxic T (Tc) cells and CD3+CD4+FoxP3+ cells (Tregs) and CD3+CD4+RORγt+ cells (Th17) remained unchanged. While in the spleens of αIL-10R+Plerixafor-treated mice displayed significant increased Tregs, but decreased Th and Tc cells. Interestingly, markedly elevated Tregs, RORγt+ Tregs and tolerogenic IL-10+ Tregs was observed in lamina propria when compared to αIL-10R+ vehicle given mice. Interestingly, the proinflammatory IL-17+ Th cells were decreased in αIL-10R+Plerixafor-treated mice which showed mild colitis. Moreover, to further elucidate the role of Plerixafor in intestinal barrier function in colitic mice, we noticed treatment with Plerixafor increased the expression of occludin and claudins (1, 2), which are the principal transmembrane tight junctions (TJ) proteins; however Plerixafor treatment reduced the expression of zonula occludens (ZO), a peripheral membrane TJ protein. Collectively, our results demonstrate that SN could be an adaptive and beneficial immune response during chronic intestinal inflammation.

INFLIXIMAB MARKET SHARE AND ASSOCIATED COST SAVINGS FOLLOWING BIOSIMILAR MARKET ENTRY

Abstract BACKGROUND Biologic medications have transformed treatment for autoimmune conditions, including inflammatory bowel disease (IBD), but have also contributed to rising healthcare expenditures in the United States (US). Biosimilars, which are highly similar in safety and efficacy to the originator biologic, were introduced to create competition and reduce cost. Limited studies exist evaluating the impact biosimilars have had on biologic market share and cost savings. The objective of this study was to evaluate the impact infliximab biosimilars have had on the cost and market share of the infliximab originator product. METHODS Infliximab claims were reviewed and analyzed using the Merative MarketScan Commercial Claims and Encounters Database. Using only outpatient claims, both the infliximab originator and biosimilars were identified using Current Procedural Terminology codes from January 1, 2015, to December 31, 2021. Patients with commercial insurance, ages 0 to 64 years, and receiving infliximab for any indication were included. The Medical Care Consumer Price Index was used to adjust for inflation to December 2021 dollars. Outcomes of interest included market share of all infliximab products, cost per infliximab infusion, and cost per vial (one vial=100 mg) of the medication. RESULTS There were 471,748 claims for infliximab infusions that met our inclusion criteria, with 42,100 unique patients, 55% female, and a median age of 40 (inter-quartile range (IQR) 26 – 52) years old at the time of medication initiation. Indications for infliximab products included IBD (67%), rheumatoid arthrtiis (18%), psoriasis (9%), ankylosing spondylitis (5%), other (4%), with some patients receiving infliximab for multiple indications. Utilization of infliximab biosimilars increased over time, reaching the highest utilization in December 2021, accounting for 24% of the market share. The median cost of the infliximab originator peaked at $1,491 per vial in December 2017, 13 months after market entry of the first biosimilar (infliximab-dyyb). The cost of the infliximab originator then decreased by 45% over time, reaching a low of $821 per vial in December 2021. Had infliximab biosimilars not been introduced to the market, the projected cost of the infliximab originator in December 2021 would have increased by 20% to $1793 per vial. Thus, infliximab biosimilars contributed to a theoretical decrease of 55% in the cost of infliximab originator during the time period studied. CONCLUSIONS The market share of infliximab biosimilars in the US has steadily increased since their introduction in 2016. The competition of infliximab biosimilars has contributed to the decrease in cost of both the infliximab originator and biosimilar products. Future studies are needed to determine if patients are seeing an out-of-pocket savings because of biosimilar introduction.