A Narrative Review of Cytokine Networks: Pathophysiological and Therapeutic Implications for Inflammatory Bowel Disease Pathogenesis

Chrysin ameliorates dextran sulfate-induced ulcerative colitis in mice by modulating inflammation and gut microbiota

BACKGROUND

Inflammatory bowel disease (IBD) encompasses chronic inflammation of the colon and rectum, posing significant health challenges. Previous studies have shown potential therapeutic effects of natural compounds on IBD. Chrysin, a naturally occurring flavonoid, has been suggested to modulate inflammatory pathways and gut microbiota, but its comprehensive impact on ulcerative colitis remains inadequately explored.

METHODS

This study employed a dextran sulfate sodium (DSS)-induced ulcerative colitis model in mice to investigate the effects of Chrysin. Using network pharmacology, we identified key signaling pathways potentially influenced by Chrysin. Experimental approaches included measuring disease activity index scores, serum levels of TNF-α, and assessing colon damage histologically. Transcriptomic and microbiome analyses were conducted to examine changes in gene expression and gut bacterial populations, respectively. Additionally, metabolomic profiling was used to identify alterations in colon metabolites.

RESULTS

Chrysin treatment significantly mitigated weight loss and reduced disease activity index scores in DSS-induced mice. There was a notable decrease in serum TNF-α levels and less histological damage in the colon. Transcriptomic analysis revealed significant alterations in gene expression within the NF-κB and IL-17 signaling pathways. Microbiome analysis showed significant shifts in the populations of Bacteroidetes and Firmicutes. Metabolomics analysis identified changes in 298 colon metabolites, implicating several essential metabolic pathways.

CONCLUSIONS

The findings suggest that Chrysin exerts a dual-action therapeutic effect on ulcerative colitis by reducing inflammation and modulating the gut microbiota. These multifaceted impacts highlight Chrysin's potential utility as a novel therapeutic agent in the clinical management of IBD, offering valuable insights into its mechanisms of action and paving the way for future clinical trials.

Chloride channels and mast cell function: pioneering new frontiers in IBD therapy

Emerging evidence indicates that chloride channels (ClCs) significantly affect the pathogenesis of inflammatory bowel disease (IBD) through their regulatory roles in mast cell function and epithelial integrity. IBD, encompassing conditions such as Crohn's disease and ulcerative colitis, involves chronic inflammation of the gastrointestinal tract, where channels influence immune responses, fluid balance, and cellular signalling pathways essential for maintaining mucosal homeostasis. This review examines the specific roles of ClC in mast cells, focussing on the regulation of mast cell activation, degranulation, cytokine release, and immune cell recruitment in inflamed tissues. Key channels, including Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and ClC-2, are discussed in detail because of their involvement in maintaining intestinal epithelial barrier function, a critical factor disrupted in IBD. For example, CFTR facilitates chloride ion transport across epithelial cells, which is essential for mucosal hydration and maintenance of the intestinal barrier. Reduced CFTR function can compromise this barrier, permitting microbial antigens to penetrate the underlying tissues and triggering excessive immune responses. ClC-2, another chloride channel expressed in mast cells and epithelial cells, supports tight junction integrity, contributes to barrier function, and reduces intestinal permeability. Dysregulation of these channels is linked to altered mast cell activity and excessive release of pro-inflammatory mediators, exacerbating IBD symptoms, such as diarrhoea, abdominal pain, and tissue damage. Here, we review recent pharmacological strategies targeting ClC, including CFTR potentiators and ClC-2 activators, which show the potential to mitigate inflammatory responses. Additionally, experimental approaches for selective modulation of chloride channels in mast cells have been explored. Although targeting ClC offers promising therapeutic avenues, challenges remain in achieving specificity and minimizing side effects. This review highlights the therapeutic potential of Cl channel modulation in mast cells as a novel approach for IBD treatment, aiming to reduce inflammation and restore intestinal homeostasis in affected patients.

In Vitro Inhibition of Endoplasmic Reticulum Stress: A Promising Therapeutic Strategy for Patients with Crohn's Disease

BACKGROUND

Crohn's disease (CD) is an inflammatory bowel disease marked by an abnormal immune response and excessive pro-inflammatory cytokines, leading to impaired protein processing and endoplasmic reticulum (ER) stress. This stress, caused by the accumulation of misfolded proteins, triggers the unfolded protein response (UPR) through IRE1/Xbp-1, PERK/eIF2α, and ATF6 pathways, which are linked to intestinal inflammation. This study aimed to investigate ER stress in CD patients' intestinal mucosa and evaluate phenylbutyrate (PBA) as an ER stress inhibitor.

METHODS

Colon biopsies from CD patients and controls were cultured under five conditions, including 4-PBA treatments. Real-time PCR, cytokine level, and immunohistochemistry were performed.

RESULTS

Immunohistochemistry revealed that ER stress was activated in CD patients' intestinal epithelial cells and lamina propria cells. PERK/eIF2α, but not IRE1/Xbp-1 or ATF6, was upregulated in CD patients compared to controls. UPR-related genes (STC2, CALR, HSPA5, HSP90B1) were also elevated in CD patients. PBA treatment significantly reduced ER stress and UPR markers while decreasing apoptotic markers like DDIT3. Pro-inflammatory cytokines, such as IL-1β, IL-6, IL-17, TNF- α, and sCD40L, were significantly reduced after PBA treatment.

CONCLUSION

ER stress and UPR pathways are activated in CD colonic mucosa, and PBA reduces these markers, suggesting potential therapeutic benefits for CD-related inflammation.

High-Throughput Whole-Exome Sequencing and Large-Scale Computational Analysis to Identify the Genetic Biomarkers to Predict the Vedolizumab Response Status in Inflammatory Bowel Disease Patients from Saudi Arabia

Background/Objectives: Vedolizumab (VDZ) is the new monoclonal drug targeting α4β7 integrin for patients with moderate/severe IBD. Between 30 and 45% of patients fail to respond to VDZ after 14-16 weeks of treatment. The aim of the study was to explore the genetic profile of vedolizumab-treated Arab IBD patients in Saudi Arabia to identify the potential biomarkers to differentiate the responders from non-responders. Methods: A cohort of 16 patients with IBD, including 4 with Crohn's disease and 12 with ulcerative colitis, were recruited. Following 16 weeks of VDZ treatment, nine were found to be responders and seven non-responders. Blood samples were collected for the whole exome sequencing of DNA from all patients. The variants in the whole-exome sequencing data were analyzed with a variety of bioinformatics tools and databases, such as Polyphen2, Mutation Taster, CADD, FATHMM, Open Target Platform, TOPPFun, STRING, and GTEx. Results: More than 1.6 million variants from 16 samples were analyzed. The rare variant analysis prioritized NOD2, IL23, IL10, IL27, and TRAF1 genes in non-responders. NOD2, IL23, IL10, IL27, and TRAF1 were found to be the significant IBD risk factors in multiple genome-wide association studies, and their pro-inflammatory activity might contribute to the inherent resistance to VDZ. Rare variants of CARD9, TYK2, IL4, and NLRP1 genes present in VDZ responders enhance the anti-inflammatory/immune modulation effects. Conclusions: This investigation is the first to apply whole-exome sequencing to identify the potential drug response biomarkers for the IBD drug VDZ in Saudi Arabia.

Immunohistochemistry Analysis in Inflammatory Bowel Disease-Should We Bring to Light Interleukin-10?

Background/Objectives: Inflammatory bowel diseases (IBDs) are chronic intestinal disorders with an unpredictable course. In parallel with the advent of new biologic therapies targeting specific interleukin pathways, end-point targets have become more stringent, aiming for mucosal and even histologic healing. Methods: We conducted a prospective study assessing immunohistochemical (IHC) parameters in 46 IBD patients treated with biologic therapy. A similar IHC analysis was performed for comparison with a cohort of 10 "non-IBD" patients. Results: The highest integrated optical density (IOD) of TNF-α was observed in patients with dysplasia, abscesses, mucin depletion and basal plasmacytosis. Non-responders had higher pre- and post-treatment TNF-α expression in both UC and CD compared to responders. On the contrary, the same analysis conducted in the subpopulation treated with anti-TNF-α therapy (Infliximab and Adalimumab) did not reveal a substantial difference in TNF-α expression between responders and non-responders. High pre-treatment interleukin-10 expression was associated with biologic therapy failure, histological inflammatory activity and longer disease duration. Conclusions: Pre-treatment assessment of IL-10 might be a useful tool for identifying a high-risk subset of IBD patients and determining a more aggressive therapy and intensive monitoring strategy.

Polyphenols mitigating inflammatory mechanisms in inflammatory bowel disease (IBD): focus on the NF-ƙB and JAK/STAT pathways

The term "inflammatory bowel disease" (IBD) refers to a group of chronic inflammatory gastrointestinal disorders, which include ulcerative colitis and Crohn's disease. The necessity for alternative therapeutic approaches is underscored by the fact that although present medicines are successful, they frequently result in considerable adverse effects. Naturally occurring substances included in fruits and vegetables called polyphenols have been shown to have the capacity to control important inflammatory pathways including NF-κB and JAK/STAT, which are essential for the pathophysiology of IBD. The processes by which polyphenols, such as curcumin, EGCG, resveratrol, and quercetin, reduce inflammation are examined in this article. Polyphenols may have therapeutic advantages by blocking the synthesis of cytokines and the activation of immune cells by targeting these pathways. Preclinical study indicates a reduction in intestinal inflammation, which is encouraging. However, more clinical research is needed to determine the clinical relevance of polyphenols in the therapy of IBD, especially with regard to their long-term safety and bioavailability.

Anti-Inflammatory Effects of Algae-Derived Biomolecules in Gut Health: A Review

Under physiological conditions, the inflammatory response acts as a biological defense against tissue damage or infection, and is rapidly resolved once the infection is cleared. However, chronic inflammatory diseases, including inflammatory bowel disease (IBD), have become increasingly widespread in the last decades, placing a burden on the quality of life of affected people and on healthcare systems worldwide. Available drug therapies are often ineffective due to the chronic nature of these diseases, and prolonged administration of drugs can result in severe side effects for the patient or a lack of efficacy. In addition, there is the growing problem of bacterial resistance to synthetic antibiotics. Together, these factors have led to a strong research focus on the discovery of natural products capable of treating IBD. Recently, there has been a growing interest in compounds derived from marine sources, mainly algae, due to their bioactive secondary metabolites with anti-inflammatory properties well known in the literature. Based on this evidence, this review aimed to evaluate the anti-inflammatory potential of algae-derived biomolecules in IBD. In particular, interesting species from green algae (e.g., Chlorella vulgaris and Ulva pertusa), brown algae (e.g., Macrocystis pyrifera and Ecklonia cava) and red algae (e.g., Porphyra tenera and Grateloupia turuturu) are included in this review due to their proven anti-inflammatory properties. For this purpose, an extensive literature search was conducted using several databases. The results suggest that both macroalgae and microalgae have remarkable potential for IBD therapy due to the anti-inflammatory and antioxidant activities of their bioactive compounds. However, while the preclinical evidence is encouraging, further and long-term clinical studies are needed to better understand their mechanisms of action in order to determine the true efficacy of marine algae in the treatment of IBD.

Assessment of the Utility of Selected Inflammatory Markers in Correlation with Magnetic Resonance Enterography (MRE) Findings in the Diagnosis of Crohn's Disease

Crohn's Disease (CD) is a chronic inflammatory bowel disease affecting the gastrointestinal tract. The search continues for new markers for assessing the activity of CD. Among them, pro-inflammatory and anti-inflammatory cytokines appear promising. We performed the analysis of cytokine concentrations in blood serum using the Bio-Plex Multiplex system (Bio-Rad), and their correlations with radiological parameters were assessed by magnetic resonance enterography (MRE), and fecal calprotectin levels were measured quantitatively by ELISA and clinical evaluation according to the Crohn's Disease Activity Index (CDAI). Our study found that measuring cytokine serum concentrations can be a valuable tool in the diagnosis and treatment of CD. Positive correlations were reported between contrast enhancement on DCE-MRE and the concentrations of PDGF-BB and RANTES. Also, a positive correlation was found between the delayed-phase of DCE and IL-10 concentration, a strong negative correlation between the delayed-phase of DCE and IL-12 concentration, and a strong positive correlation between the delayed-phase of DCE and RANTES concentrations. A strong positive correlation was also observed between the thickness of the intestinal wall on T2-weighted images and RANTES concentration. Therefore, concentrations of PDGF-BB, RANTES, IL-10 and IL-12 are promising markers of CD activity. The study also demonstrated significant correlations between the severity of disease activity assessed by the CDAI and the concentrations of IL-5, IL-8 and IL-9, as well as positive correlations between the levels of fecal calprotectin and the concentrations of IL-1RA and VEGF. Therefore, the levels of IL-5, IL-8, IL-9, VEGF and IL-1RA may be useful markers in the diagnosis and clinical assessment of disease activity.

Chronic Gastrointestinal Disorders and miRNA-Associated Disease: An Up-to-Date

Chronic gastrointestinal disorders such as inflammatory bowel diseases (IBDs) and irritable bowel syndrome (IBS) impose significant health burdens globally. IBDs, encompassing Crohn's disease and ulcerative colitis, are multifactorial disorders characterized by chronic inflammation of the gastrointestinal tract. On the other hand, IBS is one of the principal gastrointestinal tract functional disorders and is characterized by abdominal pain and altered bowel habits. Although the precise etiopathogenesis of these disorders remains unclear, mounting evidence suggests that non-coding RNA molecules play crucial roles in regulating gene expression associated with inflammation, apoptosis, oxidative stress, and tissue permeability, thus influencing disease progression. miRNAs have emerged as possible reliable biomarkers, as they can be analyzed in the biological fluids of patients at a low cost. This review explores the roles of miRNAs in IBDs and IBS, focusing on their involvement in the control of disease hallmarks. By an extensive literature review and employing bioinformatics tools, we identified the miRNAs frequently studied concerning these diseases. Ultimately, specific miRNAs could be proposed as diagnostic biomarkers for IBDs and IBS. Their ability to be secreted into biofluids makes them promising candidates for non-invasive diagnostic tools. Therefore, understanding molecular mechanisms through the ways in which they regulate gastrointestinal inflammation and immune responses could provide new insights into the pathogenesis of IBDs and IBS and open avenues for miRNA-based therapeutic interventions.

De novo interleukin-10 production primed by Lactobacillus sakei CVL-001 amplifies the immunomodulatory abilities of mesenchymal stem cells to alleviate colitis

Mesenchymal stem cells (MSCs) hold therapeutic promise for treating inflammatory bowel disease (IBD) owing to their immunomodulatory properties. Currently, pre-conditioning strategies with several beneficial agents have been applied to enhance the efficacy of MSCs in treating IBDs. Probiotics are increasingly acknowledged as supplemental therapy for IBD; however, their potential benefits in MSCs-based therapy remain largely unexplored. In this study, we hypothesized that pretreating MSCs with Lactobacillus sakei CVL-001 (L. sakei CVL-001), a representative probiotic strain, could improve their therapeutic effectiveness for IBD. In line with this hypothesis, we noted that pretreatment with L. sakei CVL-001 significantly induced IL-10 secretion in MSCs via the activation of the STAT3 signaling pathway. These primed MSCs reduced pro-inflammatory cytokine production in LPS/IFN-γ-treated macrophages and promoted an M2 phenotype, associated with immunoregulation and tissue repair, in undifferentiated macrophages. In addition, their conditioned media significantly reduced the proliferation capacity of Jurkat T cells and splenocytes, while the neutralization of IL-10 reversed these phenomena. Furthermore, MSCs treated with L. sakei CVL-001 mitigated inflammatory responses and promoted epithelial regeneration, leading to accelerated recovery from disease symptoms and improved survival rates compared to naive MSCs in a DSS-induced colitis mouse model. In conclusion, our findings suggest that probiotics, such as L. sakei CVL-001, can improve the therapeutic efficacy of MSCs for treating IBD.

Bromodomain-Containing 4 Is a Positive Regulator of Interleukin-34 Production in the Gut

Experimental evidence suggests that, in the inflamed gut of inflammatory bowel disease (IBD) patients, interleukin-34 (IL-34) triggers detrimental signaling pathways. Factors/mechanisms regulating IL-34 production in IBD remain poorly characterized. Bromodomain-containing 4 (BRD4), a transcriptional and epigenetic regulator, is over-expressed in IBD, and studies in cancer cells suggest that BRD4 might positively control IL-34 expression. This study aimed to assess whether, in IBD, BRD4 regulates IL-34 expression. In IBD, there was an up-regulation of both IL-34 and BRD4 compared to the controls, and the two proteins co-localized in both lamina propria mononuclear cells (LPMCs) and epithelial cells. Flow cytometry analysis of CD45+ LPMCs confirmed that the percentages of IL-34- and BRD4-co-expressing cells were significantly higher in IBD than in the controls and showed that more than 80% of the IL-34-positive CD45-LPMCs expressed BRD4. IL-34 and BRD4 were mainly expressed by T cells and macrophages. IL-34 expression was reduced in IBD LPMCs transfected with BRD4 antisense oligonucleotide and in the colons of mice with dextran sulfate sodium-induced colitis treated with JQ1, a pharmacological inhibitor of BRD4. These data indicate that BRD4 is a positive regulator of IL-34 in IBD, further supporting the pathogenic role of BRD4 in IBD-associated mucosal inflammation.

Key Disease-Related Genes and Immune Cell Infiltration Landscape in Inflammatory Bowel Disease: A Bioinformatics Investigation

Inflammatory Bowel Diseases (IBD), which encompass ulcerative colitis (UC) and Crohn's disease (CD), are characterized by chronic inflammation and tissue damage of the gastrointestinal tract. This study aimed to uncover novel disease-gene signatures, dysregulated pathways, and the immune cell infiltration landscape of inflamed tissues. Eight publicly available transcriptomic datasets, including inflamed and non-inflamed tissues from CD and UC patients were analyzed. Common differentially expressed genes (DEGs) were identified through meta-analysis, revealing 180 DEGs. DEGs were implicated in leukocyte transendothelial migration, PI3K-Akt, chemokine, NOD-like receptors, TNF signaling pathways, and pathways in cancer. Protein-protein interaction network and cluster analysis identified 14 central IBD players, which were validated using eight external datasets. Disease module construction using the NeDRex platform identified nine out of 14 disease-associated genes (CYBB, RAC2, GNAI2, ITGA4, CYBA, NCF4, CPT1A, NCF2, and PCK1). Immune infiltration profile assessment revealed a significantly higher degree of infiltration of neutrophils, activated dendritic cells, plasma cells, mast cells (resting/activated), B cells (memory/naïve), regulatory T cells, and M0 and M1 macrophages in inflamed IBD tissue. Collectively, this study identified the immune infiltration profile and nine disease-associated genes as potential modulators of IBD pathogenesis, offering insights into disease molecular mechanisms, and highlighting potential disease modulators and immune cell dynamics.

Immunity in digestive diseases: new drugs for inflammatory bowel disease treatment-insights from Phase II and III trials

BACKGROUND

Inflammatory bowel disease (IBD), encompassing Crohn's disease (CD) and ulcerative colitis (UC), continues to challenge treatment paradigms. Advancements in therapeutic options have been have been driven by Phase 2 and 3 clinical trials of new drug classes, particularly sphingosine-1-phosphate (S1P) modulators and interleukin-23 (IL-23) inhibitors.

METHODS

This review synthesizes findings from Phase 2 and 3 clinical trials conducted up to early 2024, focusing on the impact of S1P modulators and IL-23 inhibitors on IBD management. Drugs such as ozanimod, etrasimod, risankizumab, mirikizumab, guselkumab, and brasikumab were evaluated for their efficacy and safety profiles.

RESULTS

S1P modulators, such as ozanimod and etrasimod, effectively regulate immune cell trafficking to reduce inflammation and several trials highlight their clinical effectiveness in both inducing and maintaining remission in IBD, highlighting its long-term safety and sustained therapeutic effects. Additionally, IL-23 inhibitors including risankizumab, mirikizumab, and guselkumab, which disrupt key inflammatory cytokine pathways, have already shown significant effectiveness in inducing and maintaining remission in both CD and UC, with favorable safety profiles across multiple studies, suggesting their potential as critical components in managing IBD.

CONCLUSIONS

The clinical trials indicate that both S1P modulators and IL-23 inhibitors offer promising therapeutic benefits and maintain strong safety profiles, positioning them as potential cornerstone treatments for IBD. Despite these advancements, further exploration into long-term safety and the development of personalized treatment strategies is essential for maximizing clinical outcomes.

Marine Algae and Deriving Biomolecules for the Management of Inflammatory Bowel Diseases: Potential Clinical Therapeutics to Decrease Gut Inflammatory and Oxidative Stress Markers?

The term "inflammatory bowel disease" (IBD) describes a class of relapse-remitting conditions that affect the gastrointestinal (GI) tract. Among these, Crohn's disease (CD) and ulcerative colitis (UC) are two of the most globally prevalent and debilitating conditions. Several articles have brought attention to the significant role that inflammation and oxidative stress cooperatively play in the development of IBD, offering a different viewpoint both on its etiopathogenesis and on strategies for the effective treatment of these conditions. Marine ecosystems may be a significant source of physiologically active substances, supporting the search for new potential clinical therapeutics. Based on this evidence, this review aims to comprehensively evaluate the activity of marine algae and deriving biomolecules in decreasing pathological features of CD and UC. To match this purpose, a deep search of the literature on PubMed (MEDLINE) and Google Scholar was performed to highlight primary biological mechanisms, the modulation of inflammatory and oxidative stress biochemical parameters, and potential clinical benefits deriving from marine species. From our findings, both macroalgae and microalgae have shown potential as therapeutic solutions for IBD due to their bioactive compounds and their anti-inflammatory and antioxidant activities which are capable of modulating markers such as cytokines, the NF-κB pathway, reactive oxidative and nitrosative species (ROS and RNS), trefoil factor 3 (TFF3), lactoferrin, SIRT1, etc. However, while we found promising preclinical evidence, more extensive and long-term clinical studies are necessary to establish the efficacy and safety of marine algae for IBD treatment.

Environmental and Genetic Determinants of Ankylosing Spondylitis

Exposure to heavy metals and lifestyle factors like smoking contribute to the production of free oxygen radicals. This fact, combined with a lowered total antioxidant status, can induce even more damage in the development of ankylosing spondylitis (AS). Despite the fact that some researchers are looking for more genetic factors underlying AS, most studies focus on polymorphisms within the genes encoding the human leukocyte antigen (HLA) system. The biggest challenge is finding the effective treatment of the disease. Genetic factors and the influence of oxidative stress, mineral metabolism disorders, microbiota, and tobacco smoking seem to be of great importance for the development of AS. The data contained in this review constitute valuable information and encourage the initiation and development of research in this area, showing connections between inflammatory disorders leading to the pathogenesis of AS and selected environmental and genetic factors.

Cytokine Signatures in Inflamed Mucosa of IBD Patients: State-of-the-Art

The process of development, recurrence, and exacerbation of the inflammatory process depends on the cytokine levels in IBD. For that reason, many cytokine therapies have been developed for treating IBD patients. Researchers employ various techniques and methodologies for cytokine profiling to identify cytokine signatures in inflamed mucosa. These include enzyme-linked immunosorbent assays (ELISA), multiplex immunoassays, flow cytometry, and gene expression analysis techniques (i.e., microarray, RNA-seq, single-cell RNA-seq (scRNA-seq), mass cytometry (CyTOF), Luminex). Research knowledge so far can give us some insights into the cytokine milieu associated with mucosal inflammation by quantifying cytokine levels in mucosal tissues or biological fluids such as serum or stool. The review is aimed at presenting state-of-the-art techniques for cytokine profiling and the various biomarkers for follow-up and treatment.

Antibiotic Therapy for Active Crohn's Disease Targeting Pathogens: An Overview and Update

Crohn's disease (CD) is a multifactorial chronic disorder that involves a combination of factors, including genetics, immune response, and gut microbiota. Therapy includes salicylates, immunosuppressive agents, corticosteroids, and biologic drugs. International guidelines do not recommend the use of antibiotics for CD patients, except in the case of septic complications. Increasing evidence of the involvement of gut bacteria in this chronic disease supports the rationale for using antibiotics as the primary treatment for active CD. In recent decades, several pathogens have been reported to be involved in the development of CD, but only Escherichia coli (E. coli) and Mycobacterium avium paratubercolosis (MAP) have aroused interest due to their strong association with CD pathogenesis. Several meta-analyses have been published concerning antibiotic treatment for CD patients, but randomized trials testing antibiotic treatment against E. coli and MAP have not shown prolonged benefits and have generated conflicting results; several questions are still unresolved regarding trial design, antibiotic dosing, the formulation used, the treatment course, and the outcome measures. In this paper, we provide an overview and update of the trials testing antibiotic treatment for active CD patients, taking into account the role of pathogens, the mechanisms by which different antibiotics act on harmful pathogens, and antibiotic resistance. Finally, we also present new lines of study for the future regarding the use of antibiotics to treat patients with active CD.