Metabolome and inflammasome in inflammatory bowel disease

Cell membrane nanomaterials composed of phospholipids and glycoproteins for drug delivery in inflammatory bowel disease: A review

Inflammatory bowel disease (IBD) is a serious chronic intestinal disorder with an increasing global incidence. However, current treatment strategies, such as anti-inflammatory drugs and probiotics, have limitations in terms of safety, stability, and effectiveness. The emergence of targeted nanoparticles has revolutionized IBD treatment by enhancing the biological properties of drugs and promoting efficiency and safety. Unlike synthetic nanoparticles, cell membrane nanomaterials (CMNs) consist primarily of biological macromolecules, including phospholipids, proteins, and sugars. CMNs include red blood cell membranes, macrophage membranes, and leukocyte membranes, which possess abundant glycoprotein receptors and ligands on their surfaces, allowing for the formation of cell-to-cell connections with other biological macromolecules. Consequently, they exhibit superior cell affinity, evade immune responses, and target inflammation effectively, making them ideal material for targeted delivery of IBD therapies. This review explores various CMNs delivery systems for IBD treatment. However, due to the complexity and harsh nature of the intestinal microenvironment, the lack of flexibility or loss of selectivity poses challenges in designing single CMNs delivery strategies. Therefore, we propose a hierarchically programmed delivery modality that combines CMNs with pH, charge, ROS and ligand-modified responsive nanoparticles. This approach significantly improves delivery efficiency and points the way for future research in this area.

Current advances in the anti-inflammatory effects and mechanisms of natural polysaccharides

Inflammatory bowel disease (IBD) is a chronic, multifactorial and inflammatory disease occurring in the colon tract. Bioactive polysaccharides from natural resources have attracted extensive attention due to their safety, accessibility and good bioactivities. In recent years, a variety of natural bioactive polysaccharides have been proven to possess anti-inflammatory effects on treating acute colitis. The objective of this review was to give an up-to-date review on the anti-inflammatory effects and mechanisms of natural polysaccharides on acute colitis. The anti-inflammatory effects of natural polysaccharides on acute colitis concerning clinical symptoms amelioration, colon tissue repairment, anti-oxidative stress alleviation, anti-inflammation, immune regulation, and gut microbiota modulation were comprehensively summarized. In addition, inducible murine models for assessing the anti-inflammatory effects of natural polysaccharides on acute colitis were also concluded. This review will offer the comprehensive understanding of anti-inflammatory mechanisms of natural polysaccharides in acute colitis, and render theoretical basis for the development and application of natural polysaccharides in drug and functional food.

Treating the Metabolic Syndrome by Fecal Transplantation-Current Status

The intestinal microbiome (IM) is important for normal gastrointestinal (GI) and other organ systems' functioning. An alteration in the normal IM, dysbiosis, and changes in intestinal motility result in microorganisms' overgrowth and an alteration in intestinal permeability. The gut-brain axis is also of importance in the irritable bowel syndrome (IBS) and associated bowel overgrowth. Secondary to the epidemic of obesity, the metabolic syndrome has become a major health problem. Disturbances in the fecal microbiome are associated with the metabolic syndrome. Metabolic-associated fatty liver disease (MAFLD) is now the current terminology for non-alcoholic fatty liver disease. IM alteration by fecal transplantation is an approved treatment method for recurrent Clostridioides difficile infection. Initially performed by either duodenal infusion or colonoscopy, it is now easily performed by the administration of capsules containing stools. We discuss the intestinal microbiome-its composition, as well as the qualitative changes of microbiome composition leading to inflammation. In addition, we discuss the evidence of the effect of fecal transplantation on the metabolic syndrome and MAFLD, as well as its clinical indications.

Transcription Factors That Regulate the Pathogenesis of Ulcerative Colitis

Ulcerative colitis (UC) is one of the inflammatory bowel diseases (IBD) characterized by occurrence in the rectum and sigmoid colon of young adults. However, the functional roles of transcription factors (TFs) and their regulating target genes and pathways are not fully known in ulcerative colitis (UC). In this study, we collected gene expression data to identify differentially expressed TFs (DETFs). We found that differentially expressed genes (DEGs) were significantly enriched in the target genes of HOXA2, IKZF1, KLF2, XBP1, EGR2, ETV7, BACH2, CBFA2T3, HLF, and NFE2. TFs including BACH2, CBFA2T3, EGR2, ETV7, NFE2, and XBP1, and their target genes were significantly enriched in signaling by interleukins. BACH2 target genes were enriched in estrogen receptor- (ESR-) mediated signaling and nongenomic estrogen signaling. Furthermore, to clarify the functional roles of immune cells on the UC pathogenesis, we estimated the immune cell proportions in all the samples. The accumulated effector CD8 and reduced proportion of naïve CD4 might be responsible for the adaptive immune response in UC. The accumulation of plasma in UC might be associated with increased gut permeability. In summary, we present a systematic study of the TFs by analyzing the DETFs, their regulating target genes and pathways, and immune cells. These findings might improve our understanding of the TFs in the pathogenesis of UC.

Selective granulocyte and monocyte apheresis in inflammatory bowel disease: Its past, present and future

The etiology and pathogenesis of inflammatory bowel disease (IBD), including ulcerative colitis and Crohn’s disease, are not fully understood so far. Therefore, IBD still remains incurable despite the fact that significant progress has been achieved in recent years in its treatment with innovative medicine. About 20 years ago, selective granulocyte and monocyte apheresis (GMA) was invented in Japan and later approved by the Japanese health authority for IBD treatment. From then on this technique was extensively used for IBD patients in Japan and later in Europe. Clinical trials from Japan and European countries have verified the effectiveness and safety of GMA therapy in patients with IBD. In 2013, GMA therapy was approved by China State Food and Drug Administration for therapeutic use for the Chinese IBD patients. However, GMA therapy has not been extensively used in China, although a few clinical studies also showed that it was effective in clinical and endoscopic induction of remission in Chinese IBD patients with a high safety profile. This article reviews past history, present clinical application as well as the future prospective of GMA therapy for patients with IBD.

Diagnostic and Clinical Significance of Serum Levels of D-Lactate and Diamine Oxidase in Patients with Crohn's Disease

Background

Crohn's disease (CD) is a chronic intestinal inflammatory disease. An ideal laboratory marker that can predict the prognosis in terms of relapse of the disease is clinically desirable.

Methods

A total of 59 CD patients were enrolled in this study. Enzyme-Linked Immunosorbent Assay (ELISA) was used to quantitatively detect the content of D-lactate (D-LA) and the diamine oxidase (DAO) levels in sera obtained from patients and 28 healthy controls. The correlation between these two biomarkers and disease activity scores was assessed. In addition, the ROC curve was used to evaluate the diagnostic accuracy of these two biomarkers.

Results

The levels of D-LA in the serum of CD patients in the active stage and remission stage were 16.08 ± 4.8 mg/L and 11.16 ± 3.17 mg/L, respectively, and the difference was statistically significant (t = 4.67, P < 0.001). DAO levels were significantly higher in patients with the active stage compared to controls. The levels of D-LA and DAO in CD patients were positively correlated with the disease activity (r = 0.68 and 0.53, respectively, P < 0.05). The area under the ROC curve (AUC) when CD activity was diagnosed with D-LA and DAO alone was 0.815 and 0.748, respectively. The diagnostic efficacy of the two biomarkers was not significantly different from that of the erythrocyte sedimentation (ESR) and hypersensitive C-reactive protein (CRP) (P > 0.05). However, the area under the curve was 0.861 (0.746, 0.937) when the diagnosis was performed using a combination of D-LA, DAO, CRP, and ESR, which was significantly higher than when CRP or ESR were tested alone (P < 0.05).

Conclusions

D-LA and DAO have a good prognostic value for CD activity. Rational combined use of biomarkers can significantly improve the diagnostic efficiency.

Mechanisms of Disease: Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs), represented by Crohn disease and ulcerative colitis, are associated with major morbidity in Western countries and with increasing incidence in the developing world. Although analysis of the genome of patients with IBD, especially through genome-wide association studies, has unraveled multiple pathways involved in IBD pathogenesis, only part of IBD heritability has been explained by genetic studies. This finding has revealed that environmental factors also play a major role in promoting intestinal inflammation, mostly through their effects in the composition of the microbiome. However, in order for microbial dysbiosis to result in uncontrolled intestinal inflammation, the intestinal barrier formed by intestinal epithelial cells and the innate immune system should also be compromised. Finally, activation of the immune system depends on the working balance between effector and regulatory cells present in the intestinal mucosa, which have also been found to be dysregulated in this patient population. Therefore, IBD pathogenesis is a result of the interplay of genetic susceptibility and environmental impact on the microbiome that through a weakened intestinal barrier will lead to inappropriate intestinal immune activation. In this article, we will review the mechanisms proposed to cause IBD from the genetic, environmental, intestinal barrier, and immunologic perspectives.

Targeting Specific Immunologic Pathways in Crohn's Disease

Understanding the immunologic pathways in intestinal inflammation is crucial for the development of new therapies that can maximize patient response and minimize toxicity. Targeting integrins and cytokines is intended to control leukocyte migration to effector sites or inhibit the action of proinflammatory cytokines. New approaches to preventing leukocyte migration may target integrin receptors expressed on the intestinal vascular endothelium. The interleukin (IL)-12/IL-23 pathway has been a therapeutic target of interest in controlling active Crohn's disease (CD). New therapeutic approaches in CD may involve the enhancement of anti-inflammatory cytokine pathways and modulation of cellular responses and intranuclear signals associated with intestinal inflammation.

Comorbidity between depression and inflammatory bowel disease explained by immune-inflammatory, oxidative, and nitrosative stress; tryptophan catabolite; and gut-brain pathways

The nature of depression has recently been reconceptualized, being conceived as the clinical expression of activated immune-inflammatory, oxidative, and nitrosative stress (IO&NS) pathways, including tryptophan catabolite (TRYCAT), autoimmune, and gut-brain pathways. IO&NS pathways are similarly integral to the pathogenesis of inflammatory bowel disease (IBD). The increased depression prevalence in IBD associates with a lower quality of life and increased morbidity in IBD, highlighting the role of depression in modulating the pathophysiology of IBD.This review covers data within such a wider conceptualization that better explains the heightened co-occurrence of IBD and depression. Common IO&NS underpinning between both disorders is evidenced by increased pro-inflammatory cytokine levels, eg, interleukin-1 (IL-1) and tumor necrosis factor-α, IL-6 trans-signalling; Th-1- and Th-17-like responses; neopterin and soluble IL-2 receptor levels; positive acute phase reactants (haptoglobin and C-reactive protein); lowered levels of negative acute phase reactants (albumin, transferrin, zinc) and anti-inflammatory cytokines (IL-10 and transforming growth factor-β); increased O&NS with damage to lipids, proteinsm and DNA; increased production of nitric oxide (NO) and inducible NO synthase; lowered plasma tryptophan but increased TRYCAT levels; autoimmune responses; and increased bacterial translocation. As such, heightened IO&NS processes in depression overlap with the biological underpinnings of IBD, potentially explaining their increased co-occurrence. This supports the perspective that there is a spectrum of IO&NS disorders that includes depression, both as an emergent comorbidity and as a contributor to IO&NS processes. Such a frame of reference has treatment implications for IBD when "comorbid" with depression.

Can we change our microbiome to prevent colorectal cancer development?

BACKGROUND

Colorectal cancer represents an important disease as one of the major causes of death worldwide. Although a lot of genetic and epigenetic research has been conducted, all the pieces of the puzzle of colorectal cancer carcinogenesis have not yet been identified. New recent data has highlighted that gut microbiota could have an influence on colorectal carcinogenesis. Gut microbiota represents the microbe population living in the human intestine and contains tens of trillions of microorganisms.

MATERIAL AND METHODS

A systematic search in Medline and PubMed for studies reporting the influence of gut microbiota and inflammation on patients with colorectal cancer was made.

RESULTS

In this review we discuss many of the specific bacteria, as well as their metabolites which may have an important role in development of colorectal cancer. Furthermore, we emphasize the molecular mechanisms modulated by gut microbiota, which promote inflammation, toxic metabolites, DNA damaging and pro-carcinogenic compounds, as support for colorectal carcinogenesis. The interrelation between microbiota and inflammation is complex because bacteria and inflammation could mutually impact upon each other. In this context, both endogenous and exogenous miRNAs may have an important role to modulate tumor-related inflammation in colorectal cancer.

CONCLUSIONS

Better understanding of the role of gut microbiota in colorectal carcinogenesis could provide promising new directions to improve both prevention and treatment of colorectal cancer. Moreover, the discovery of novel biomarkers in the gut microbiome in order to detect colorectal cancer in an early stage or even in a precancerous stage is of outmost importance.

Decreased levels of serum omentin-1 in patients with inflammatory bowel disease

BACKGROUND

Inflammation is involved in the mechanism of inflammatory bowel disease (IBD). Omentin, a newly discovered adipokine, is thought to play an anti-inflammatory role. This study aimed to determine whether serum levels of omentin-1 are associated with the presence and disease activity of IBD.

MATERIAL/METHODS

This study consisted of 192 patients with IBD: 100 with Crohn's disease [CD], 92 with ulcerative colitis [UC], and 104 healthy subjects. Serum levels of omentin-1 were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Serum omentin-1 levels were significantly decreased in CD and UC patients compared with healthy controls. Multivariable logistic regression analysis revealed that serum omentin-1 levels were inversely associated with the presence of CD and UC. Active CD and UC patients both had significantly decreased levels of serum omentin-1 compared with inactive CD and UC patients. In both CD and UC patients, serum omentin-1 levels were significantly associated with decreased levels of body mass index (BMI) and C-reactive protein (CRP).

CONCLUSIONS

Decreased serum omentin-1 levels could be considered as an independent predicting marker of the presence and disease activity of IBD.

Generation of outbred Ace2 knockout mice by RNA transfection of TALENs displaying colitis reminiscent pathophysiology and inflammation

The angiotensin I converting enzyme 2 (ACE2) is a key factor in the maintenance of intestinal homeostasis. Dysregulation of homeostasis can lead to inflammation of the colon (colitis), which can cause life-threatening enfeeblement or even cancer. Animal models are valuable surrogates in deciphering the pathology behind such human conditions and for screening of putative therapeutic targets or treatment paradigms. However, development of disease models can be time-consuming and technical demanding, which might hamper their application-value. In this study, we genetically disrupted the mouse Ace2 gene by direct injection of in vitro transcribed mRNA coding for transcription activator-like effector nucleases (TALENs) into the cytoplasm of outbred Kunming mouse zygotes. Consequently, somatic mutations were induced with an efficiency of 57 %, of which 39 % were frameshift mutations. Moreover, all modifications were stably transferred during germline transmission. In Ace2-knockout male mice (Ace2^−/y), we observed severe chemical induced colitis, characterized by considerable weight loss, diarrhea and a shortened colon length. Histologically, Ace2 mutations resulted in the infiltration of leukocytes and the overt damage of the intestinal mucosal barrier. In addition, we detected an increased expression of inflammatory cytokines in the colon tissue of Ace2^−/y mice. Collectively, the data indicate that high targeting efficiency and heritability can be achieved in an outbred mouse model by zygote injection of TALEN mRNA. Furthermore, the generated Ace2^−/y mice display phenotypic traits reminiscent of colitis and we anticipate that such mice can be of value in studies of the intestinal microbiome or fecal transplantation.

Crohn's disease and growth deficiency in children and adolescents

Nutritional concerns, linear growth deficiency, and delayed puberty are currently detected in up to 85% of patients with Crohn’s disease (CD) diagnosed at childhood. To provide advice on how to assess and manage nutritional concerns in these patients, a Medline search was conducted using “pediatric inflammatory bowel disease”, “pediatric Crohn’s disease”, “linear growth”, “pubertal growth”, “bone health”, and “vitamin D” as key words. Clinical trials, systematic reviews, and meta-analyses published between 2008 and 2013 were selected to produce this narrative review. Studies referring to earlier periods were also considered if the data was relevant to our review. Although current treatment strategies for CD that include anti-tumor necrosis factor-α therapy have been shown to improve patients’ growth rate, linear growth deficiencies are still common. In pediatric CD patients, prolonged diagnostic delay, high initial activity index, and stricturing/penetrating type of behavior may cause growth deficiencies (in weight and height) and delayed puberty, with several studies reporting that these patients may not reach an optimal bone mass. Glucocorticoids and inflammation inhibit bone formation, though their impact on skeletal modeling remains unclear. Long-term control of active inflammation and an adequate intake of nutrients are both fundamental in promoting normal puberty. Recent evidence suggests that recombinant growth factor therapy is effective in improving short-term linear growth in selected patients, but is of limited benefit for ameliorating mucosal disease and reducing clinical disease activity. The authors conclude that an intense initial treatment (taking a “top-down” approach, with the early introduction of immunomodulatory treatment) may be justified to induce and maintain remission so that the growth of children with CD can catch up, ideally before puberty. Exclusive enteral nutrition has a key role in inducing remission and improving patients’ nutritional status.

Biologic therapies in inflammatory bowel disease

Inflammatory bowel disease, including its 2 entities ulcerative colitis and Crohn's disease, is a chronic medical condition characterized by the destructive inflammation of the intestinal tract. Biologics represent a class of therapeutics with immune intervention potential. These agents block the proinflammatory cascade that triggers the activation and proliferation of T lymphocytes at the level of the intestine, therefore reestablishing the balance between the pro- and anti-inflammatory messages. All 7 biologics showing clinical benefits in inflammatory bowel disease are monoclonal antibodies. The following systematic review discusses the pharmacokinetics and efficacy of the tumor necrosis factor blockers infliximab, adalimumab, certolizumab pegol, and golimumab. In addition, we describe the α4 integrin inhibitors natalizumab and vedolizumab, which are directed against cell adhesion molecules, as well as the interleukin 12/23 blocker ustekinumab.

Lactoferrin prevents invasion and inflammatory response following E. coli strain LF82 infection in experimental model of Crohn's disease

BACKGROUND

Crohn's disease is a multifactorial disease in which an aberrant immune response to commensal intestinal microbiota leads to chronic inflammation. The small intestine of patients with Crohn's disease is colonized by a group of adherent-invasive Escherichia coli strongly able to adhere and invade intestinal epithelial cells lactoferrin is an iron-binding glycoprotein known to have anti-bacterial and anti-inflammatory activities.

AIMS

We explore the ability of bovine lactoferrin to modulate the interactions between the adherent-invasive E. coli strain LF82 and intestinal epithelial cells as well as the inflammatory response.

METHODS

Bacterial adhesion and invasion assays were used to assess the antimicrobial activity of lactoferrin. Electron microscopy was used to characterize bacteria-cell interactions. The mRNA expression of pro-inflammatory cytokines was measured both in cultured cells and in biopsies taken from intestine of patients affected by Crohn's disease.

RESULTS

Lactoferrin inhibited bacterial invasion through minimally affecting adhesion. This divergence was due to a mannose-dependent lactoferrin binding to the bacterial type 1 pili and consequent bacterial aggregation on the intestinal epithelial cell surface. Expression of pro-inflammatory cytokines, such as TNF-alpha, IL-8, and IL-6, was markedly inhibited by lactoferrin both in cultured and Crohn-derived intestinal cells.

CONCLUSIONS

Bovine lactoferrin might function via an antibacterial and/or anti-inflammatory mechanism in the treatment of Crohn's disease.

Inflammation and colorectal cancer: colitis-associated neoplasia

Connection between inflammation and cancer is a rapidly developing field. Epidemiological data suggests that inflammation along with distinct arms of host immune system plays a very important role in the development and progression of many different cancers. Inflammatory bowel disease (IBD) is an important risk factor for the development of colon cancer, namely, colitis-associated cancer (CAC). The molecular mechanisms by which inflammation promotes cancer development are still being uncovered and may differ between CAC and other forms of colorectal cancer. Recent work has shed light on the role of distinct immune cells, cytokines, and other immune mediators in virtually all of the steps of colonic tumorigenesis, including tumor initiation and promotion as well as progression and metastasis. The close proximity of colonic tumors to the myriad of intestinal microbes, as well as instrumental role of microbiota in IBD, introduces microbes as new players capable of triggering inflammation and possibly promoting tumorigenesis. Various mechanisms of CAC tumorigenesis as well as new possible hints for the future approaches for prevention and therapy are discussed in this review.

Nutritional and probiotic supplementation in colitis models

In vitro and animals models have long been used to study human diseases and identify novel therapeutic approaches that can be applied to combat these conditions. Ulcerative colitis and Crohn's disease are the two main entities of inflammatory bowel disease (IBD). There is an intricate relationship between IBD features in human patients, in vitro and animal colitis models, mechanisms and possible therapeutic approaches in these models, and strategies that can be extrapolated and applied in humans. Malnutrition, particularly protein-energy malnutrition and vitamin and micronutrient deficiencies, as well as dysregulation of the intestinal microbiota, are common features of IBD. Based on these observations, dietary supplementation with essential nutrients known to be in short supply in the diet in IBD patients and with other molecules believed to provide beneficial anti-inflammatory effects, as well as with probiotic organisms that stimulate immune functions and resistance to infection has been tested in colitis models. Here we review current knowledge on nutritional and probiotic supplementation in in vitro and animal colitis models. While some of these strategies require further fine-tuning before they can be applied in human IBD patients, their intended purpose is to prevent, delay or treat disease symptoms in a non-pharmaceutical manner.