Increased monocyte abundance as a marker for relapse after discontinuation of biologics in inflammatory bowel disease with deep remission

Juglans regia L. (Walnut) Leaf Extract Ameliorates Pulmonary Edema Against Airway Inflammation via Upregulation of Tight Junction Proteins and Heme Oxygenase-1 in the Lungs of Asthmatic Mice

Background: Juglans regia L. is renowned for its traditional use as a cure for respiratory diseases such as asthma and sinusitis. Objectives: This study was intended to assess the protective mechanism of the effects of hydroalcoholic extract of the leaf of Juglans regia L. against airway inflammation and pulmonary edema by measuring the expression levels of heme oxygenase-1 (HO-1), occludin, and Zonula occludens-1 (ZO-1) in the lung tissues. Methods: Ovalbumin (OVA) was used intraperitoneally to sensitize mice on Days 0 and 14 to induce allergic asthma by the intraperitoneal route. Animals were divided into 5 groups, consisting of normal control (NC), disease group (OVA, i.p), low-dose J. regia (LDJR) and high-dose J. regia (HDJR), methylprednisolone (MP), and reference control (RC) drug. On the 28th day, blood and bronchial alveolar lavage fluid (BALF) were collected for total leukocyte (TLC) and differential leukocyte (DLC) analysis. Hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining of the lungs were performed for the architectural changes caused by OVA-induced bronchial asthma. Tight junction proteins were assessed by measuring the expression levels of HO-1, occludin, and ZO-1 in the lung tissues by using real-time polymerase chain reaction. Results: Scores of inflammations, edema, and goblet cell hyperplasia were significantly increased (all p ≤ 0.05) in the DC group compared to the NC group, while treatment with LDJR and HDJR significantly reduced (all p ≤ 0.05) the scores of inflammations, edema, and goblet cell hyperplasia compared to the DC group. Real-time polymerase chain reaction data showed that expression levels of HO-1, occludin, and ZO-1 in lung tissues of the DC group were significantly reduced (all p ≤ 0.05), when the same was compared to the NC group, while treatment with LDJR and HDJR significantly increased (p ≤ 0.05) their expression level when compared to the DC group. Conclusion: Juglans regia L.'s hydroalcoholic extract possesses antiasthmatic activity by normalizing the TLC cells and DLC cells. Juglans regia L.'s hydroalcoholic extract resulted in the amelioration of pulmonary edema which is attributed to the upregulation of HO-1, occludin, and ZO-1 in the lung tissues of the Juglans regia L. treated groups when compared to the diseased control group. Administration of Juglans regia L.'s extract also reduces the scores of inflammation and vascular congestion by evaluation of the lungs' histopathology in the disease control group when compared to the NC group.

Diagnostic value of lymphocyte-to-monocyte ratio in Crohn's disease: a cross-sectional study

Background

Investigating non-invasive laboratory biomarkers for detecting and classifying Crohn's disease (CD) activity remains challenging. Here, we aimed to evaluate the diagnostic efficacy of immunological biomarkers in identifying disease activity in newly diagnosed CD patients.

Methods

This cross-sectional study was performed from October 2022 to July 2023 and included 20 healthy participants and 46 confirmed newly diagnosed CD patients in a Teaching Hospital for Gastroenterology and Hepatology, Sulaimani, Iraq. The patients were categorized according to the disease activity assessed according to the Harvey-Bradshaw Index and divided into remission and active CD.

Results

A statistically higher serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels were found among the remission CD group (P = 0.005 and P = 0.0002, respectively) and active CD group (P < 0.0001 and P < 0.0001, respectively) compared to the healthy controls. Moreover, the mean CRP and ESR levels among active CD were also considerably higher than those of remission CD (P = 0.018 and P = 0.005, respectively). The lymphocyte-to-monocyte ratio (LMR) was significantly lower in patients with active disease (3.01 ± 1.36) than in remission patients (6.77 ± 2.17) (cutoff < 4.42, area under receiver-operating characteristic curve (ROC) = 0.807, 95% CI, 77.35-98.73%, 93% sensitivity, and 78% specificity). Although the neutrophil-to-lymphocyte ratio (NLR) was significantly elevated in active patients (3.64 ± 2.004) compared to healthy controls (1.91 ± 0.48; P = 0.0001), it is not usable for disease activity or severity as the area under the ROC curve was 0.68 (95% CI, 52.22-85.08%, sensitivity = 79%, specificity = 62%).

Conclusion

The LMR can be an affordable, easily accessible test that shows promise for determining disease activity in newly diagnosed CD patients.

Exhaustion profile on classical monocytes after LPS stimulation on Crohn's disease patients

Crohn's disease is a type of inflammatory bowel disease that leads to symptoms such as diarrhea, abdominal pain, weight loss, and increased risk of developing tumors. The immune system plays a vital role in the gastrointestinal tract by maintaining tolerance to commensal antigens and food. However, in Crohn's disease, this tolerance mechanism is disrupted, resulting in chronic inflammatory responses. The involvement of the immune system is central to Crohn's disease, with a wide range of immune cells including monocytes, being affected. Due to the limited understanding of the role of monocytes in Crohn's disease, our study aimed to clarify the cytokine production and activation profile of monocytes subsets in the context of this condition. We used multiparametric flow cytometry to analyze the status of monocyte, quantified gene expression using qPCR, and created a correlation matrix to connect the flow cytometry data with the qPCR results through a bioinformatics approach. Our findings indicate that patients with Crohn's disease show a reduction in all monocyte subsets. Additionally, classical monocytes exhibit an exhaustion profile characterized by increased CD38 expression and reduced IL-1β production following LPS stimulation in patient groups. These results suggest that monocyte subsets play distinct roles in the disease's pathophysiology of Crohn's disease, potentially contributing to chronic inflammation and impairing the resolution of the immune response.

Predicting complications in paediatric ulcerative colitis: A longitudinal multicentre cohort study

BACKGROUND

To prevent complications of paediatric ulcerative colitis (UC), it is critical to understand their predictors. The Paediatric Inflammatory Bowel Disease Ahead (PIBD Ahead) program identified the relevant outcomes and their potential predictors. However, external validation of these results in larger cohorts is required.

AIMS

The aim of this study is to investigate these outcomes and their predictors.

METHODS

We included 743 patients aged under 18 years with UC from the multicentre German-Austrian CEDATA-GPGE registry. We performed Cox regressions, Kaplan-Meier estimator, and receiver operating characteristics curve analyses to analyse predictors of poor outcomes.

RESULTS

Older age at diagnosis was associated with relapse, hospitalisation, the use of immunomodulators, use of biologics, and therapy escalation. Higher disease activity, as in acute severe colitis in the first 3 months, was significantly associated with further acute severe colitis and the need for biologics. Upper gastrointestinal tract involvement was a risk factor for the need of intravenous corticosteroids and biologics. A faecal calprotectin of >685 μg/g was associated with a higher risk of subsequent acute severe colitis with a sensitivity of 79.0% and a specificity of 59.1%. A lower haematocrit at diagnosis was predictive of the use of biologics. Colectomy was rare.

CONCLUSIONS

This study validates predictors of poor outcomes in paediatric patients with UC. Our results might help physicians to anticipate poor outcomes and initiate appropriate treatment strategies at an early stage.

Interrupting inflammatory bowel disease therapy: why, who, when and how to consider medication holidays

INTRODUCTION

Medication holidays in inflammatory bowel disease (IBD) offer a potential means to balance disease management, costs, and quality of life. This concept is increasingly relevant in light of the chronic nature of IBD, the cumulative side effects associated with long-term pharmacotherapy, and the evolving treatment landscape that now includes a large armamentarium of effective induction, maintenance, and rescue therapies paired with disease monitoring tools that enable early intervention.

AREAS COVERED

This review critically examines the rationale, implementation, and risks of medication holidays in IBD. Recent evidence is reviewed to help guide the risks of relapse involved with cessation of therapy. The selection criteria for patients, the necessary monitoring protocols, and strategies for managing potential relapses are outlined.

EXPERT OPINION

Despite the potential benefits, medication holidays in IBD involve significant risks and require careful patient selection and active management. Current research highlights a need for improved predictive models and a deeper understanding of patient-specific outcomes and consequences. The future of medication holidays will depend heavily on advancements in noninvasive monitoring technologies and more personalized approaches to therapy. Ultimately, establishing clearer guidelines for safely conducting medication holidays will be crucial in integrating this strategy into routine clinical practice.

An Oxidative Cleavage-Based Cruciform DNA Nanostructure for In Vivo Hypochlorous Acid Visualization to Monitor Intestinal Inflammation

Ulcerative colitis is a persistent inflammatory bowel disease characterized by inflammation and ulceration in the colon and gastrointestinal tract. It was indicated that the generation of hypochlorous acid (HClO) through the enzymatic activity of myeloperoxidase is significantly linked to ulcerative colitis. In this study, by assembling two hairpins (Hpa and Hpb) onto a quadrivalent cruciform DNA nanostructure, a novel HClO-activatable fluorescent probe was developed based on DNA nanomaterials (denoted MHDNA), which is sensitive, economic, simple, and stable. In the presence of HClO, the Trigger (T) was liberated from the MHDNA probe through a hydrolysis reaction between HClO and phosphorothioate (PS), which is modified on the MHDNA probe and has proved to exhibit particular susceptibility to the HClO. The liberated T subsequently initiated the opening of Hpa and Hpb to facilitate the catalyzed hairpin assembly (CHA) reaction, resulting in the changes of fluorescence and releasing T for recycled signal amplification to achieve sensitive detection of HClO (with a limit of detection 9.83 nM). Additionally, the MHDNA-based spatial-confinement effect shortens the physical distance between Hpa and Hpb and yields a high local concentration of the two reactive hairpins, achieving more rapid reaction kinetics in comparison to conventional CHA methods. Inspirationally, the MHDNA probe was effectively utilized for imaging HClO in ulcerative colitis mice, yielding valuable diagnostic insights for ulcerative colitis.

The association between circulating leukocytes and inflammatory bowel disease: a two-sample Mendelian randomization study

Background

Inflammatory bowel disease (IBD) is a highly prevalent, recurrent, chronic intestinal inflammatory disease. Several observational studies have shown that circulating leukocytes are strongly associated with IBD. However, whether alterations in leukocytes are causally related to IBD remains uncertain. The present study explores this issue with the Mendelian randomization (MR) analysis method.

Methods

The Genome wide association study (GWAS) statistical data related to circulating leukocytes and IBD were obtained from the Blood Cell Consortium and the IEU Qpen GWAS project, respectively. Inverse variance weighting (IVW) was used as the main MR analytical method, coupled with a series of sensitivity analyses to ensure the reliability of the results.

Results

The results of IVW showed that increased monocyte count (especially CD14- CD16+ monocyte absolute counts) was negatively correlated with the risk of IBD and its main subtypes. Increased neutrophil count was positively associated with the risk of IBD and ulcerative colitis. Meanwhile, there was no causal relationship between basophil, eosinophil, lymphocyte counts and IBD risk.

Conclusion

These results indicate that a causal relationship exists between circulating leukocytes and the risk of IBD and its subtypes, which confirms the important role that the leukocyte immune system plays in IBD. Our findings provide additional research directions for the clinical prevention and treatment of IBD.

Challenges in IBD Research 2024: Precision Medicine

Precision medicine is part of 5 focus areas of the Challenges in IBD Research 2024 research document, which also includes preclinical human IBD mechanisms, environmental triggers, novel technologies, and pragmatic clinical research. Building on Challenges in IBD Research 2019, the current Challenges aims to provide a comprehensive overview of current gaps in inflammatory bowel diseases (IBDs) research and deliver actionable approaches to address them with a focus on how these gaps can lead to advancements in interception, remission, and restoration for these diseases. The document is the result of multidisciplinary input from scientists, clinicians, patients, and funders, and represents a valuable resource for patient-centric research prioritization. In particular, the precision medicine section is focused on the main research gaps in elucidating how to bring the best care to the individual patient in IBD. Research gaps were identified in biomarker discovery and validation for predicting disease progression and choosing the most appropriate treatment for each patient. Other gaps were identified in making the best use of existing patient biosamples and clinical data, developing new technologies to analyze large datasets, and overcoming regulatory and payer hurdles to enable clinical use of biomarkers. To address these gaps, the Workgroup suggests focusing on thoroughly validating existing candidate biomarkers, using best-in-class data generation and analysis tools, and establishing cross-disciplinary teams to tackle regulatory hurdles as early as possible. Altogether, the precision medicine group recognizes the importance of bringing basic scientific biomarker discovery and translating it into the clinic to help improve the lives of IBD patients.

Origin and Function of Monocytes in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a chronic disease resulting from the interaction of various factors such as social elements, autoimmunity, genetics, and gut microbiota. Alarmingly, recent epidemiological data points to a surging incidence of IBD, underscoring an urgent imperative: to delineate the intricate mechanisms driving its onset. Such insights are paramount, not only for enhancing our comprehension of IBD pathogenesis but also for refining diagnostic and therapeutic paradigms. Monocytes, significant immune cells derived from the bone marrow, serve as precursors to macrophages (Mφs) and dendritic cells (DCs) in the inflammatory response of IBD. Within the IBD milieu, their role is twofold. On the one hand, monocytes are instrumental in precipitating the disease's progression. On the other hand, their differentiated offsprings, namely moMφs and moDCs, are conspicuously mobilized at inflammatory foci, manifesting either pro-inflammatory or anti-inflammatory actions. The phenotypic spectrum of these effector cells, intriguingly, is modulated by variables such as host genetics and the subtleties of the prevailing inflammatory microenvironment. Notwithstanding their significance, a palpable dearth exists in the literature concerning the roles and mechanisms of monocytes in IBD pathogenesis. This review endeavors to bridge this knowledge gap. It offers an exhaustive exploration of monocytes' origin, their developmental trajectory, and their differentiation dynamics during IBD. Furthermore, it delves into the functional ramifications of monocytes and their differentiated progenies throughout IBD's course. Through this lens, we aspire to furnish novel perspectives into IBD's etiology and potential therapeutic strategies.

Absolute monocyte counts could predict disease activity and secondary loss of response of patients with Crohn's disease treated with anti-TNF-α drug

BACKGROUND

Assessing Crohn's disease (CD) activity is critical for monitoring disease progression. In CD, monocytes could release TNF-α. Thus, it is extremely important to study its role in the disease activity and loss of response to anti-TNF-α biologics.

METHODS

In this study, we collected CD patients treated with biologics from January 2017 to May 2022. Indicators associated with disease activity were evaluated by Spearman correlation analysis and Mann-Whitney U test. Specifically, logistic analyses were used to explore the predictors of primary nonresponse (PNR) and secondary loss of response (SLOR) within 1 year of anti-TNF-α agents. In addition, a nomogram was developed for therapeutic effect prediction.

RESULTS

283 patients with CD were identified. Disease activity group, defined as CDAI equal to or greater than 150, had significant elevated absolute monocyte counts than disease remission group based on CDAI score (p = 0.019, Z = -2.354). Logistic analyses showed that absolute monocyte counts could be an independent predictor of 1-year SLOR of anti-TNF-α agents in CD patients (p = 0.013). A nomogram established based on gender, absolute monocyte counts, and hemoglobin could predict SLOR within 1 year of anti-TNF-α agents reliably.

CONCLUSION

The results of this study support the utility of absolute monocyte counts detecting disease activity and anti-TNF-α therapy effect in patients with CD.

Immune-Modulating Effects of Low-Carbohydrate Ketogenic Foods in Healthy Canines

Background

Ketogenic foods limit digestible carbohydrates but contain high fat, and have antioxidant and anti-inflammatory effects as well as improving mitochondrial function. β-Hydroxybutyrate (BHB), 1 of the ketone bodies, reduces the proinflammatory NLR family pyrin domain containing 3 inflammasomes, as well as chemokines in cultures.

Objectives

We assessed the immune-modulating effects of 2 low-carbohydrate (LoCHO) foods varying in protein and fat and compared their effects with a food replete with high-carbohydrate (HiCHO) in healthy canines.

Methods

Dogs were fed control food [HiCHO; ketogenic ratio (KR: 0.46) followed by LoCHO_PROT (KR: 0.97), then LoCHO_FAT (KR: 1.63) or LoCHO_FAT followed by LoCHO_PROT. Each food was fed for 5 wk, with collections in the 5th wk; 15 wk feeding total. Gene expression for circulating inflammatory cytokines from 10 dogs was assessed using the Canine RT2 Profiler polymerase chain reaction array, and fold changes were calculated using the ΔΔCt method.

Results

LoCHO_FAT significantly increased circulating β-hydroxybutyrate compared with both HiCHO and LoCHO_PROT. When compared with HiCHO, there was a significant decrease in several proinflammatory cytokines/chemokines in LoCHO_PROT and LoCHO_FAT groups, including chemokine (C-C motif) ligand (CCL)1, CCL8, CCL13, CCL17, CCL24, chemokine (C-X3-C motif) ligand 1, chemokine (C-X-C motif) receptor 1, Interleukin-10 receptor alpha ((IL)-10RA), IL-1 receptor antagonist, IL-5, and secreted phosphoprotein 1 (all P < 0.05). Interestingly, a subset of inflammatory proteins that decreased in LoCHO_PROT but not in LoCHO_FAT included IL-33, IL-6 receptor, IL-7, IL-8, Nicotinamide phosphoribosyltransferase, and tumor necrosis factor (TNF) receptor superfamily member 11B. In contrast, the decrease in inflammatory markers in LoCHO_FAT, but not in LoCHO_PROT, included complement component 5, granulocyte colony-stimulating factor or G-CSF, interferon-γ, IL-3, IL-10RB, IL-17C, Tumor necrosis factor superfamily (TNFSF)13, TNFSF13B, and TNFSF14. Decreased concentrations of selected cytokines indicate that both low-carbohydrate foods exert an anti-inflammatory effect and provide a strong rationale for testing their efficacy in dogs with inflammatory conditions.

Conclusions

Both LoCHO_PROT and LoCHO_FAT foods might be important as part of immune-modulating therapeutic nutritional strategies to reduce inflammation to maintain health in canines. Our study identifies several inflammatory genes that are reduced when fed ketogenic food that were not previously reported.

Integrated single-cell and bulk RNA sequencing reveals CREM is involved in the pathogenesis of ulcerative colitis

Background

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by persistent colonic inflammation. Here, we performed a systematic analysis to gain better insights into UC pathogenesis.

Methods

We analyzed two UC-related datasets extracted from the gene expression omnibus database using several bioinformatics tools. The primary cell types and key subgroups of primary cells associated with UC and differentially expressed genes (DEGs) between UC and control samples were identified. The molecular regulation of the key genes was also predicted. The gene ontology and Kyoto encyclopedia of genes and genomes enrichment analyses of marker genes of key cell subgroups and model genes were performed. The expression of key enriched genes was validated in 10 clinical samples using real-time quantitative polymerase chain reaction (RT-qPCR).

Results

Monocytes were identified as the major cell type. Ten differentially expressed marker genes were obtained by intersecting the 3121 DEGs, 38 marker genes in major cell types, and 104 marker genes in key cell subgroups. Four essential genes, associated with immune response, were obtained using support vector machine recursive feature elimination and least absolute shrinkage and selection operator analyses. The four essential genes were highly expressed in Cluster 0 during differentiation. Validation of the four key genes in colonic mucosal biopsy specimens from 10 normal and 10 UC patients revealed that CREM was highly expressed in both the lesion-free sites and lesion sites colonic mucosa of UC patients compared with normal adults.

Conclusions

We identified CREM involved in UC pathogenesis, which is expected to provide a new therapeutic target for UC.

A leaky gut dysregulates gene networks in the brain associated with immune activation, oxidative stress, and myelination in a mouse model of colitis

The gut and brain are increasingly linked in human disease, with neuropsychiatric conditions classically attributed to the brain showing an involvement of the intestine and inflammatory bowel diseases (IBDs) displaying an ever-expanding list of neurological comorbidities. To identify molecular systems that underpin this gut-brain connection and thus discover therapeutic targets, experimental models of gut dysfunction must be evaluated for brain effects. In the present study, we examine disturbances along the gut-brain axis in a widely used murine model of colitis, the dextran sodium sulfate (DSS) model, using high-throughput transcriptomics and an unbiased network analysis strategy coupled with standard biochemical outcome measures to achieve a comprehensive approach to identify key disease processes in both colon and brain. We examine the reproducibility of colitis induction with this model and its resulting genetic programs during different phases of disease, finding that DSS-induced colitis is largely reproducible with a few site-specific molecular features. We focus on the circulating immune system as the intermediary between the gut and brain, which exhibits an activation of pro-inflammatory innate immunity during colitis. Our unbiased transcriptomics analysis provides supporting evidence for immune activation in the brain during colitis, suggests that myelination may be a process vulnerable to increased intestinal permeability, and identifies a possible role for oxidative stress and brain oxygenation. Overall, we provide a comprehensive evaluation of multiple systems in a prevalent experimental model of intestinal permeability, which will inform future studies using this model and others, assist in the identification of druggable targets in the gut-brain axis, and contribute to our understanding of the concomitance of intestinal and neuropsychiatric dysfunction.

A leaky gut dysregulates gene networks in the brain associated with immune activation, oxidative stress, and myelination in a mouse model of colitis

The gut and brain are increasingly linked in human disease, with neuropsychiatric conditions classically attributed to the brain showing an involvement of the intestine and inflammatory bowel diseases (IBDs) displaying an ever-expanding list of neurological comorbidities. To identify molecular systems that underpin this gut-brain connection and thus discover therapeutic targets, experimental models of gut dysfunction must be evaluated for brain effects. In the present study, we examine disturbances along the gut-brain axis in a widely used murine model of colitis, the dextran sodium sulfate (DSS) model, using high-throughput transcriptomics and an unbiased network analysis strategy coupled with standard biochemical outcome measures to achieve a comprehensive approach to identify key disease processes in both colon and brain. We examine the reproducibility of colitis induction with this model and its resulting genetic programs during different phases of disease, finding that DSS-induced colitis is largely reproducible with a few site-specific molecular features. We focus on the circulating immune system as the intermediary between the gut and brain, which exhibits an activation of pro-inflammatory innate immunity during colitis. Our unbiased transcriptomics analysis provides supporting evidence for immune activation in the brain during colitis, suggests that myelination may be a process vulnerable to increased intestinal permeability, and identifies a possible role for oxidative stress and brain oxygenation. Overall, we provide a comprehensive evaluation of multiple systems in a prevalent experimental model of intestinal permeability, which will inform future studies using this model and others, assist in the identification of druggable targets in the gut-brain axis, and contribute to our understanding of the concomitance of intestinal and neuropsychiatric dysfunction.

Protective Effect of Lactiplantibacillus plantarum subsp. plantarum SC-5 on Dextran Sulfate Sodium-Induced Colitis in Mice

Inflammatory bowel disease (IBD) is a specific immune-associated intestinal disease. At present, the conventional treatment for patients is not ideal. Probiotics are widely used in the treatment of IBD patients due to their ability to restore the function of the intestinal mucosal barrier effectively and safely. Lactiplantibacillus plantarum subsp. plantarum is a kind of probiotic that exists in the intestines of hosts and is considered to have good probiotic properties. In this study, we evaluated the therapeutic effect of Lactiplantibacillus plantarum subsp. plantarum SC-5 (SC-5) on dextran sulfate sodium (DSS)-induced colitis in C57BL/6J mice. We estimated the effect of SC-5 on the clinical symptoms of mice through a body weight change, colon length, and DAI score. The inhibitory effects of SC-5 on the levels of cytokine IL-1β, IL-6, and TNF-α were determined by ELISA. The protein expression levels of NF-κB, MAPK signaling pathway, and the tight junction proteins occludin, claudin-3, and ZO-1 were verified using Western Blot and immunofluorescence. 16S rRNA was used to verify the modulatory effect of SC-5 on the structure of intestinal microbiota in DSS-induced colitis mice. The results showed that SC-5 could alleviate the clinical symptoms of DSS-induced colitis mice, and significantly reduce the expression of pro-inflammatory cytokines in the colon tissue. It also attenuated the inflammatory response by inhibiting the protein expression of NF-κB and MAPK signaling pathways. SC-5 improved the integrity of the intestinal mucosal barrier by strengthening tight junction proteins. In addition, 16S rRNA sequencing demonstrated that SC-5 was effective in restoring intestinal flora balance, as well as in increasing the relative abundance and diversity of beneficial microbiota. These results indicated that SC-5 has the potential to be developed as a new probiotic candidate that prevents or alleviates IBD.