Carrageenan induces interleukin-8 production through distinct Bcl10 pathway in normal human colonic epithelial cells

Food additives and their implication in inflammatory bowel disease and metabolic syndrome

Over the past half a century the Western diet (WD) has become saturated with food additives. During the same time, there has been an increase in Western diseases, such as inflammatory bowel disease (IBD) and metabolic syndrome (MetS). Emerging research has shown that food additives may be implicated in these diseases. However, critics have suggested that some of this research is problematic and may cause unnecessary fear amongst consumers. Here we review the emerging research concerning food additives and their implication in IBD and MetS, and criticisms thereof. To make the review more relevant to the WD, we only included common food additives, selected using supermarket data. Over a dozen common food additives from four categories were identified for their potential role in directly promoting these diseases. A consistent limitation of the research was the use of unrealistic human exposure conditions, such as high doses and modes of administration, as well as a lack of human trials. Another limitation was the absence of studies investigating the potential synergetic effect of consuming multiple food additives, as is common in the WD. Despite the limitations, there is some evidence that common food additives may be contributing to these additives, especially via their dysbiotic effect on the gut microbiota.

Carrageenan as a Potential Factor of Inflammatory Bowel Diseases

Carrageenan is a widely used food additive and is seen as a potential candidate in the pharmaceutical industry. However, there are two faces to carrageenan that allows it to be used positively for therapeutic purposes. Carrageenan can be used to create edible films and for encapsulating drugs, and there is also interest in the use of carrageenan for food printing. Carrageenan is a naturally occurring polysaccharide gum. Depending on the type of carrageenan, it is used in regulating the composition of intestinal microflora, including the increase in the population of Bifidobacterium bacteria. On the other hand, the studies have demonstrated the harmfulness of carrageenan in animal and human models, indicating a direct link between diet and intestinal inflammatory states. Carrageenan changes the intestinal microflora, especially Akkermansia muciniphilia, degrades the mucous barrier and breaks down the mucous barrier, causing an inflammatory reaction. It directly affects epithelial cells by activating the pro-inflammatory nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) pathway. The mechanism is based on activation of the TLR4 receptor, alterations in macrophage activity, production of proinflammatory cytokines and activation of innate immune pathways. Carrageenan increases the content of Bacteroidetes bacteria, also causing a reduction in the number of short chain fatty acid (SCFA)-producing bacteria. The result is damage to the integrity of the intestinal membrane and reduction of the mucin layer. The group most exposed to the harmful effects of carrageenan are people suffering from intestinal inflammation, including Crohn disease (CD) and ulcerative colitis (UC).

Emerging Roles of Gut Serotonin in Regulation of Immune Response, Microbiota Composition and Intestinal Inflammation

Although the exact etiology of inflammatory bowel diseases (IBD) is unknown, studies have shown that dysregulated immune responses, genetic factors, gut microbiota, and environmental factors contribute to their pathogenesis. Intriguingly, serotonin (5-hydroxytryptamine or 5-HT) seems to be a molecule with increasingly strong implications in the pathogenesis of intestinal inflammation, affecting host physiology, including autophagy and immune responses, as well as microbial composition and function. 5-HT may also play a role in mediating how environmental effects impact outcomes in IBD. In this review, we aim to explore the production and important functions of 5-HT, including its impact on the gut. In addition, we highlight the bidirectional impacts of 5-HT on the immune system, the gut microbiota, and the process of autophagy and how these effects contribute to the manifestation of intestinal inflammation. We also explore recent findings connecting 5-HT signalling and the influence of environmental factors, particularly diet, in the pathogenesis of IBD. Ultimately, we explore the pleiotropic effects of this ancient molecule on biology and health in the context of intestinal inflammation.

Identification of gut microbes-related molecular subtypes and their biomarkers in colorectal cancer

The role of gut microbes (GM) and their metabolites in colorectal cancer (CRC) development has attracted increasing attention. Several studies have identified specific microorganisms that are closely associated with CRC occurrence and progression, as well as key genes associated with gut microorganisms. However, the extent to which gut microbes-related genes can serve as biomarkers for CRC progression or prognosis is still poorly understood. This study used a bioinformatics-based approach to synthetically analyze the large amount of available data stored in The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Through this analysis, this study identified two distinct CRC molecular subtypes associated with GM, as well as CRC markers related to GM. In addition, these new subtypes exhibit significantly different survival outcomes and are characterized by distinct immune landscapes and biological functions. Gut microbes-related biomarkers (GMRBs), IL7 and BCL10, were identified and found to have independent prognostic value and predictability for immunotherapeutic response in CRC patients. In addition, a systematic collection and review of prior research literature on GM and CRC provided additional evidence to support these findings. In conclusion, this paper provides new insights into the underlying pathological mechanisms by which GM promotes the development of CRC and suggests potentially viable solutions for individualized prevention, screening, and treatment of CRC.

Evidence and hypotheses on adverse effects of the food additives carrageenan (E 407)/processed Eucheuma seaweed (E 407a) and carboxymethylcellulose (E 466) on the intestines: a scoping review

This scoping review provides an overview of publications reporting adverse effects on the intestines of the food additives carrageenan (CGN) (E 407)/processed Eucheuma seaweed (PES) (E 407a) and carboxymethylcellulose (CMC) (E 466). It includes evidence from human, experimental mammal and in vitro research publications, and other evidence. The databases Medline, Embase, Scopus, Web of Science Core Collection, Cochrane Database of Systematic Reviews and Epistemonikos were searched without time limits, in addition to grey literature. The publications retrieved were screened against predefined criteria. From two literature searches, 2572 records were screened, of which 224 records were included, as well as 38 records from grey literature, making a total of 262 included publications, 196 on CGN and 101 on CMC. These publications were coded and analyzed in Eppi-Reviewer and data gaps presented in interactive maps. For CGN, five, 69 and 33 research publications on humans, experimental mammals and in vitro experiments were found, further separated as degraded or native (non-degraded) CGN. For CMC, three human, 20 animal and 14 in vitro research publications were obtained. The most studied adverse effects on the intestines were for both additives inflammation, the gut microbiome, including fermentation, intestinal permeability, and cancer and metabolic effects, and immune effects for CGN. Further studies should focus on native CGN, in the form and molecular weight used as food additive. For both additives, randomized controlled trials of sufficient power and with realistic dietary exposure levels of single additives, performed in persons of all ages, including potentially vulnerable groups, are needed.

Mechanisms of gut epithelial barrier impairment caused by food emulsifiers polysorbate 20 and polysorbate 80

BACKGROUND

The rising prevalence of many chronic diseases related to gut barrier dysfunction coincides with the increased global usage of dietary emulsifiers in recent decades. We therefore investigated the effect of the frequently used food emulsifiers on cytotoxicity, barrier function, transcriptome alterations, and protein expression in gastrointestinal epithelial cells.

METHODS

Human intestinal organoids originating from induced pluripotent stem cells, colon organoid organ-on-a-chip, and liquid-liquid interface cells were cultured in the presence of two common emulsifiers: polysorbate 20 (P20) and polysorbate 80 (P80). The cytotoxicity, transepithelial electrical resistance (TEER), and paracellular-flux were measured. Immunofluorescence staining of epithelial tight-junctions (TJ), RNA-seq transcriptome, and targeted proteomics were performed.

RESULTS

Cells showed lysis in response to P20 and P80 exposure starting at a 0.1% (v/v) concentration across all models. Epithelial barrier disruption correlated with decreased TEER, increased paracellular-flux and irregular TJ immunostaining. RNA-seq and targeted proteomics analyses demonstrated upregulation of cell development, signaling, proliferation, apoptosis, inflammatory response, and response to stress at 0.05%, a concentration lower than direct cell toxicity. A proinflammatory response was characterized by the secretion of several cytokines and chemokines, interaction with their receptors, and PI3K-Akt and MAPK signaling pathways. CXCL5, CXCL10, and VEGFA were upregulated in response to P20 and CXCL1, CXCL8 (IL-8), CXCL10, LIF in response to P80.

CONCLUSIONS

The present study provides direct evidence on the detrimental effects of food emulsifiers P20 and P80 on intestinal epithelial integrity. The underlying mechanism of epithelial barrier disruption was cell death at concentrations between 1% and 0.1%. Even at concentrations lower than 0.1%, these polysorbates induced a proinflammatory response suggesting a detrimental effect on gastrointestinal health.

How does carrageenan cause colitis? A review

Carrageenan is a common additive, but mounting studies have reported that it may cause or aggravate inflammation in the intestines. The safety of carrageenan remains controversial and its inflammatory mechanisms are unclear. In this review, the pathogenesis of colitis by carrageenans was discussed. We analyzed the pathogenesis of inflammatory bowel disease, followed that line of thought, the existing evidence of carrageenans causing colitis in cellular and animal models was summarized to draw its colitis pathogenesis. Two pathways were described including: 1) carrageenan changed the composition of intestinal microbiota, especially Akkermansia muciniphila, which destroyed the mucosal barrier and triggered the inflammatory immune response; and 2) carrageenan directly contacted with receptors on epithelial cells and activated the NF-κB inflammatory pathway. This review aim to provide guidance for exploring the treatment of colitis caused by carrageenan, and safe processing and utilization of carrageenan in food industry, which is worthy of study in the future.

What Should I Eat? Dietary Recommendations for Patients with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic disorder thought to be caused by enteric inflammation in a genetically susceptible host. Although the pathogenesis of IBD is largely unknown, it is widely accepted that dietary components play an important role. Human and animal-based studies have explored the role of various dietary components such as meat, artificial sweeteners and food additives in causing enteric inflammation. Several diets have also been studied in patients with IBD, specifically their role in the induction or maintenance of remission. The most well-studied of these include exclusive enteral nutrition and specific carbohydrate diet. A diet low in FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols), typically prescribed for patients with irritable bowel syndrome, has also been studied in a specific subgroup of patients with IBD. In this review, we describe the current evidence on how various dietary components can induce enteric and colonic inflammation, and the clinical-epidemiological evidence exploring their role in predisposing to or protecting against the development of IBD. We also discuss several special diets and how they affect clinical outcomes in IBD patients. Based on the available evidence, we provide guidance for patients and clinicians managing IBD regarding the best practice in dietary modifications.

Vitex trifolia L. modulates inflammatory mediators via down-regulation of the NF-κB signaling pathway in carrageenan-induced acute inflammation in experimental rats

ETHNOPHARMACOLOGICAL RELEVANCE

Vitex trifolia L. (V. trifolia L.), commonly known as the three-leaved chaste tree, is extensively employed in traditional Chinese medicine (TCM) to treat various conditions associated with inflammation.

AIM OF THE STUDY

The present study aimed to delineate the molecular mechanisms responsible for the anti-inflammatory effect of V. trifolia L. in carrageenan (CA)-induced acute inflammation in experimental rats.

MATERIALS AND METHODS

CA-induced rat paw edema model was adopted to investigate the anti-inflammatory effect of methanolic extract from leaves of V. trifolia L. (VTME) in vivo. Leukocyte infiltration into the site of inflammation was determined by histopathological analysis. Further, the effect of VTME on CA-induced local and systemic levels of specific cytokines was quantified by enzyme-linked immunosorbent assay (ELISA). Moreover, its impact on the nuclear translocation of nuclear factor Kappa B (NF-κB) was analyzed by employing the western blotting technique.

RESULTS

VTME at the doses of 100 mg/kg and 200 mg/kg significantly inhibited the paw edema induced by CA (p < 0.05) and effectively reduced the inflammatory leukocyte infiltration. Further, VTME markedly inhibited the CA-induced levels of Interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α in tissue, and that of cytokine-induced neutrophil chemoattractant (CINC)-2/C-X-C motif chemokine (CXCL)3 and CINC-3/CXCL2 in tissue as well as in serum. On the other hand, VTME significantly upregulated the tissue concentration of anti-inflammatory cytokine IL-10. Moreover, VTME significantly attenuated the CA-induced IκBα degradation and nuclear translocation of NF-κB p65.

CONCLUSIONS

Our results demonstrate the potent anti-inflammatory effect of V. trifolia L. in vivo, providing insight into its molecular mechanism, which is mediated through down-regulation of NF-κB signal transduction.

Ultra-processed foods as a possible culprit for the rising prevalence of inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are chronic inflammatory disorders of the gastrointestinal tract, and the exact pathogenesis is still unclear. It is believed that IBD develops in response to a complex interaction between the microbiota, environmental factors, and the immune system, in genetically predisposed individuals. Identifying these environmental factors will offer more insight in the development of the disease, and reveal new therapeutic targets for IBD patients. One of the environmental factors that has gained more interest over the last years is our diet. The prevalence of IBD has increased significantly and this increase is thought to be associated with a ‘Western diet', characterized by high intake of fats, added sugar, meat, and ultra-processed foods (UPFs). The UPFs now account for almost 50% of the energy intake in Westernized countries and are therefore an important characteristic of this Western diet. UPFs are characterized by higher amounts of salt, fat, sugar and the presence of different food additives. Epidemiological studies have found associations between UPF intake and a range of non-communicable diseases, including inflammatory bowel disease (IBD). Preclinical and clinical evidence suggest that non-nutritive ingredients and additives, present in UPFs, can negatively affect different components of the intestinal barrier, such as the microbiota, the mucus layer, the epithelium, and the immune cells in the lamina propria. Disruption of this barrier can cause the immune system to encounter an increased bacterial exposure, leading to an aberrant immune response. In this article, the available evidence on the possible role of UPFs and their components in the increasing incidence and prevalence of IBD is reviewed. These findings can be translated to the clinic and may be helpful to consider when giving dietary advice to IBD patients. A better understanding of the role of UPFs may lead to less restrictive diets for patients with IBD, hence increasing the dietary compliance and efficacy of exclusion diets.

Dietary management of adults with IBD - the emerging role of dietary therapy

Historically, dietitians played a minor part in the management of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis. Patients were commonly referred for consequences of uncontrolled disease, such as malnutrition and bowel obstruction risk. Today, dietitians are fundamental members of the multidisciplinary IBD team, from educating on the role of diet at diagnosis and throughout the lifespan of a patient with IBD to guiding primary induction therapy. This aspect is reflected in published guidelines for IBD management, which previously placed diet as only a minor factor, but now have diet-specific publications. This Review describes a four-step approach in a dietitian's assessment and management of diet in patients with IBD: (1) identifying and correcting nutritional gaps and dietary imbalances; (2) considering diet to treat active disease with the use of exclusive enteral nutrition (EEN) or emerging diets that could replace EEN; (3) using therapeutic diets to control existing complications of IBD, such as reduced fibre to prevent bowel obstruction in stricturing disease or a fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet to manage co-existing functional gut symptoms; and (4) considering the role of diet in preventing IBD development in high-risk populations.

Food Emulsifiers and Metabolic Syndrome: The Role of the Gut Microbiota

The use of emulsifiers in processed foods and the rapid epidemic development of metabolic syndrome in Western countries over the past 20 years have generated growing interest. Evidence for the role of emulsifiers in metabolic syndrome through gut microbiota has not been clearly established, thus making it challenging for clinical nutritionists and dietitians to make evidence-based associations between the nature and the quantity of emulsifiers and metabolic disorders. This narrative review summarizes the highest quality clinical evidence currently available about the impact of food emulsifiers on gut microbiota composition and functions and the potential development of metabolic syndrome. The state-of-the-art of the different common emulsifiers is performed, highlighting where they are present in daily foods and their roles. Recent findings of in vitro, in vivo, and human studies assessing the effect of different emulsifiers on gut microbiota have been recently published. There is some progress in understanding how some food emulsifiers could contribute to developing metabolic diseases through gut microbiota alterations while others could have prebiotic effects. However, there are still many unanswered questions regarding daily consumption amounts and the synergic effects between emulsifiers' intake and responses by the microbial signatures of each individual.

Assessment of Antifungal Efficacy and Release Behavior of Fungicide-Loaded Chitosan-Carrageenan Nanoparticles against Phytopathogenic Fungi

Biopolymeric Chitosan-Carrageenan nanocomposites 66.6-231.82 nm in size containing the chemical fungicide mancozeb (nano CSCRG-M) were synthesized following a green chemistry approach. The physicochemical study of nanoparticles (NPs) was accomplished using a particle size analyzer, SEM and FTIR. TEM exhibited clover leaf-shaped nanoparticles (248.23 nm) with mancozeb on the inside and entrapped outside. Differential scanning calorimetry and TGA thermogravimetry exhibited the thermal behaviour of the nanoform. Nano CSCRG-1.5 at 1.5 ppm exhibited 83.1% inhibition against Alternaria solani in an in vitro study and performed as well as mancozeb (84.6%). Complete inhibition was exhibited in Sclerotinia sclerotiorum at 1.0 and 1.5 ppm with the nanoformulation. The in vivo disease control efficacy of mancozeb-loaded nanoparticles against A. solani in pathogenized plants was found to be relatively higher (79.4 ± 1.7) than that of commercial fungicide (76 ± 1.1%) in pot conditions. Nanomancozeb showed superior efficacy for plant growth parameters, such as germination percentage, root-shoot ratio and dry biomass. The nanoformulation showed higher cell viability compared to mancozeb in Vero cell cultures at 0.25 and 0.50 mg/mL in the resazurin assay. CSCRG-0.5 showed slow-release behavior up to 10 h. Thus, these green nano-based approaches may help combat soil and water pollution caused by harmful chemical pesticides.

The mechanism exploration of the non-colonic toxicity and obesity inhibition of food-grade κ-carrageenan by transcriptome

Previous study has suggested the colonic nontoxicity and obesity inhibition of food-grade κ-carrageenan in obese mice. Further study using transcriptome is important to provide further understanding on the gene expressions of inflammation and obesity. Here, the obese mice without any treatment (HFD) or with 5% food-grade κ-carrageenan diet intervention (H5%) were used to perform colonic transcriptome sequencing. The results showed that genes involved in the inflammatory pathways or tight junction protein encoding were not significantly dysregulated by 5% carrageenan. However, the expression of lipid metabolism genes meaningfully changed as evidenced by the decreased gene levels of adipocytokines, lipogenesis, lipid absorption and transport, and the increased adipolysis and oxidation. In addition, the carrageenan metabolism experiments by toluidine blue (TB) staining of colon and high-performance size exclusion chromatography (HPSEC) of feces supernatant showed that the food-grade κ-carrageenan was not absorbed or significantly degraded in the digestive tract of obese mice. Hence, the fact that food-grade κ-carrageenan was not significantly metabolized by the organism and did not cause obvious dysregulation of colonic inflammatory genes provided evidences for its noncolonic toxicity in obese mice. An anti-obesity potential of food-grade κ-carrageenan was probably mediated by the regulation of lipids metabolism-related genes.

Determination of Carrageenan in Livestock and Poultry Meat by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry

Ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) has become the main method for the detection and analysis of food additives because of its good separation, high selectivity, and high sensitivity. The aim of this study was to establish an UHPLC-MS/MS method that can quickly and accurately measure the content of carrageenan in livestock and poultry meat. Chromatographic separation was performed on an ACQUITY UPLC BEH HILIC C18 column (2.1 mm × 50 mm, 1.7 μm) using a gradient elution with methanol and 0.1% (v/v) formic acid in water as a mobile phase. The quantitative analysis was executed using a triple quadrupole mass spectrometer in which electrospray ionization, multiple reaction monitoring, and negative mode were operated. The retention time was about 1.3 min for carrageenan. The carrageenan content showed a good linear relationship from 0.05 to 1.00 g/kg. The limit of detection (LOD) was 0.06 g/kg, and the limit of quantification (LOQ) was 0.18 g/kg. The standards were spiked at three levels (low, medium, and high) and were analyzed in six replicates. The recovery values of carrageenan in pork, beef, lamb, chicken, and duck meat were 82.06-111.55%, 85.43-112.50%, 89.55-116.00%, 83.80-102.15%, and 82.41-110.90%, respectively. The relative standard deviations (RSDs) were all lower than 7.51%. The developed method shows a high recovery rate and good precision and can be used for the rapid detection of carrageenan in livestock and poultry meat.

The Role of Carrageenan in Inflammatory Bowel Diseases and Allergic Reactions: Where Do We Stand?

Carrageenan (CGN) is a high molecular weight polysaccharide extracted from red seaweeds, composed of D-galactose residues linked in β-1,4 and α-1,3 galactose-galactose bond, widely used as a food additive in processed foods for its properties as a thickener, gelling agent, emulsifier, and stabilizer. In recent years, with the spread of the Western diet (WD), its consumption has increased. Nonetheless, there is a debate on its safety. CGN is extensively used as an inflammatory and adjuvant agent in vitro and in animal experimental models for the investigation of immune processes or to assess the activity of anti-inflammatory drugs. CGN can activate the innate immune pathways of inflammation, alter the gut microbiota composition and the thickness of the mucus barrier. Clinical evidence suggests that CGN is involved in the pathogenesis and clinical management of inflammatory bowel diseases (IBD), indeed food-exclusion diets can be an effective therapy for disease remission. Moreover, specific IgE to the oligosaccharide α-Gal has been associated with allergic reactions commonly referred to as the "α-Gal syndrome". This review aims to discuss the role of carrageenan in inflammatory bowel diseases and allergic reactions following the current evidence. Furthermore, as no definitive data are available on the safety and the effects of CGN, we suggest gaps to be filled and advise to limit the human exposure to CGN by reducing the consumption of ultra-processed foods.

Food Additive Emulsifiers and Their Impact on Gut Microbiome, Permeability, and Inflammation: Mechanistic Insights in Inflammatory Bowel Disease

The global burden of inflammatory bowel disease [IBD] has increased over the 21st century. Despite multiple studies investigating the pathogenesis of IBD, the causative mechanisms pertaining to its increased prevalence remain unclear. There is growing evidence that aspects of a 'Western diet' increase the risk of developing IBD. More recently, evidence implicating dietary emulsifiers has accumulated, with ecological studies showing a positive correlation between inflammatory bowel disease and emulsifier consumption. Further to these, cell and animal studies have demonstrated plausible mechanisms by which dietary emulsifiers may contribute to IBD pathogenesis through mechanisms including: promotion of pro-inflammatory intestinal microbiota; disruption of mucus architecture; increased intestinal permeability; activation of inflammatory pathways; and disruption of the cell cycle. This review critically analyses the current evidence for these mechanisms that may be of pathological relevance to IBD, evaluates recent dietary trials, acknowledges the challenges of dietary intervention studies, and gives an overview of ongoing and future clinical trials in this important area.

Chestnut Shell Tannins: Effects on Intestinal Inflammation and Dysbiosis in Zebrafish

Simple Summary

With the increase in global population the production of animal proteins becomes increasingly crucial. Aquaculture is the first animal protein supply industry for human consumption. Intensive farming techniques are employed to increase productivity, but these may cause stressful conditions for fish, resulting in impaired growth and poor health conditions. Intestinal inflammation is one of the most common diseases of fish in intensive farming. Intestinal inflammation is usually accompanied by an alteration of the microbiota or dysbiosis. Inflammation and dysbiosis are so tightly intertwined that inflammation may contribute to or result from dysregulation of gut microbiota. Natural substances of plant origin rich in bioactive molecules or more simply phytochemicals, have been proved to be able to reduce inflammation and improve the general health status in various commercially relevant species. In this study, we evaluated the effect of tannins, a class of polyphenols, the most abundant phytochemicals, on intestinal inflammation and microbiota in zebrafish (Danio rerio), a small freshwater fish become an attractive biomedicine and aquaculture animal model during the last decades. The zebrafish has been employed in a vast array of studies aiming at investigating the essential processes underlying intestinal inflammation and injury due to its conservative gut morphology and functions. In this study, we administered a diet enriched with chestnut shell extract rich in tannins to a zebrafish model of intestinal inflammation. The treatment ameliorated the damaged intestinal morphophysiology and the microbiota asset. Our results sustain that products of natural origin with low environmental impact and low cost, such as tannins, may help to ease some of the critical issues affecting the aquaculture sector.

Abstract

The aim of the present study was to test the possible ameliorative efficacy of phytochemicals such as tannins on intestinal inflammation and dysbiosis. The effect of a chestnut shell (Castanea sativa) extract (CSE) rich in polyphenols, mainly represented by tannins, on k-carrageenan-induced intestinal inflammation in adult zebrafish (Danio rerio) was tested in a feeding trial. Intestinal inflammation was induced by 0.1% k-carrageenan added to the diet for 10 days. CSE was administered for 10 days after k-carrageenan induced inflammation. The intestinal morphology and histopathology, cytokine expression, and microbiota were analyzed. The k-carrageenan treatment led to gut lumen expansion, reduction of intestinal folds, and increase of the goblet cells number, accompanied by the upregulation of pro-inflammatory factors (TNFα, COX2) and alteration in the number and ratio of taxonomic groups of bacteria. CSE counteracted the inflammatory status enhancing the growth of health helpful bacteria (Enterobacteriaceae and Pseudomonas), decreasing the pro-inflammatory factors, and activating the anti-inflammatory cytokine IL-10. In conclusion, CSE acted as a prebiotic on zebrafish gut microbiota, sustaining the use of tannins as food additives to ameliorate the intestinal inflammation. Our results may be relevant for both aquaculture and medical clinic fields.

Diet in Treatment of Inflammatory Bowel Diseases

There has been an alarming increase in the incidence of inflammatory bowel diseases (IBDs) worldwide over the past several decades. The pathogenesis of IBD involves genetic and environmental factors. Diet is a potentially modifiable environmental risk factor for IBD onset and severity. Diet can promote intestinal inflammation by dysregulating the immune system, altering intestinal permeability and the mucous layer, contributing to microbial dysbiosis, and other mechanisms. Dietary changes therefore might be incorporated into therapeutic strategies for IBD. Enteral nutrition is effective in the treatment of pediatric patients with luminal Crohn's disease, but there have been few studies of the effects of dietary interventions with whole foods-most of these have been studies of exclusion diets in patients with Crohn's disease. We review findings from studies of the effects of dietary patterns, single micronutrients, and food additives in inducing and maintaining remission in patients with IBD. We discuss future directions for research and propose a framework for studies of dietary interventions in the treatment of IBD.

Macroalgal dietary glycans: potential source for human gut bacteria and enhancing immune system for better health

Macroalgae are the diverse group of photosynthetic algae found at the intertidal regions of oceans. Recent advances suggest that macroalgal derived glycans have tremendous potential to maintain gut microbiome and immune system. The human gut bacteria harbor unique arsenals for utilizing a variety of macroalgal glycans, and produce a variety of oligosaccharides in vivo. Those oligosaccharides interact with immune cell receptors, and also are available for microbial fermentation, thus play magnificent roles in balancing the gut homeostasis. However, this area of research is still in infancy condition in term to understand their molecular interactions. For wooing this area, we urge to emphasize more studies on mechanistic level sympathetic of depolymerizing marine dietary glycans by gut bacteria and elucidating molecular aspect of glycans to cell receptors interactions. This will invent new nutraceutical strategies to purposefully manipulate the microbial composition to improve health. Therefore, review focuses on the recent development of mechanistic understanding of human gut bacterial communities for utilizing macroalgal derived glycans. Recent trends of application of glycans in modulating immune system at mechanistic level and their available evidences are discussed.

Semi-refined carrageenan promotes generation of reactive oxygen species in leukocytes of rats upon oral exposure but not in vitro

AIM

To assess the ability of the common food additive E407a (semi-refined carrageenan) to enter leukocytes in vitro and generate reactive oxygen species (ROS) in leukocytes as a whole and granulocytes in particular, both during incubation and in experimental animals.

METHODS

ROS production was assessed in leukocytes incubated with E407a for 2 h at the final concentrations of 5 and 10 g/L using the dye 2',7'-dichlorodihydrofluorescein diacetate (H₂DCFDA), as well as in cells isolated from rats orally exposed to E407a (140 mg/kg of weight) during 2 weeks (n = 8) and control rats (n = 8), by flow cytometry. Carrageenan uptake by leukocytes was estimated by confocal microscopy using incubation of rhodamine B isothiocyanate-labelled carrageenan with leukocyte suspensions.

RESULTS

Uptake of carrageenan by viable neutrophils, monocytes, and lymphocytes was confirmed. Oral administration of the food additive E407a was associated with excessive ROS formation by viable leukocytes (CD45⁺, 7‑aminoactinomycin D^- cells) and especially in granulocytes. Unexpectedly, a direct impact of semi-refined carrageenan during incubation for 2 h did not affect ROS production in leukocytes, evidenced by statistically insignificant differences in mean fluorescence intensity values of 2',7'-dichlorofluorescein, which is a ROS-sensitive product of intracellular H₂DCFDA conversion. Oral intake of E407a and direct exposure of leukocyte suspensions to it decreased the viability of leukocytes.

CONCLUSION

Food-grade carrageenan can enter leukocytes without affecting ROS generation as a result of incubation for 2 h with leukocyte suspensions. On the contrary, oral exposure to E407a is accompanied by ROS overproduction by white blood cells, suggesting an indirect mechanism for the stimulation of ROS synthesis in vivo. E407a promotes cell death of leukocytes both in vivo and in vitro.

Emulsifiers Impact Colonic Length in Mice and Emulsifier Restriction is Feasible in People with Crohn's Disease

There is an association between food additive emulsifiers and the prevalence of Crohn’s disease. This study aimed to investigate: (i) the effect of different classes of emulsifiers on markers of intestinal inflammation in mice and (ii) the feasibility, nutritional adequacy and symptom impact of restricting all emulsifier classes in Crohn’s disease. Mice were exposed to different classes of emulsifiers (carboxymethycellose, polysorbate-80, soy lecithin, gum arabic) in drinking water for 12-weeks, after which markers of inflammation and metabolism were measured. A low emulsifier diet was developed to restrict all classes of emulsifiers and its feasibility measured over 14-days in 20 participants with stable Crohn’s disease. Crohn’s disease-related symptoms, disease control, body weight and composition, nutrient intake and food-related quality of life (QoL) were measured. All emulsifiers resulted in lower murine colonic length compared with control (mean 9.5 cm (SEM 0.20)), but this only reached significance for polysorbate-80 (8.2 cm (0.34), p = 0.024) and carboxymethylcellulose (8.0 cm (0.35), p = 0.013). All 20 participants completed the feasibility study. The frequency of consuming emulsifier-containing foods decreased by 94.6% (SD 10.3%). Food-related QoL improved between habitual (median 81.5 (IQR 25.0)) and low emulsifier diet (90.0 (24.0), p = 0.028). Crohn’s disease-related symptoms reduced (median 3.0 (IQR 5.3) vs. 1.4 (3.9), p = 0.006), and disease control scores improved (13.5 (IQR 6.0) vs. 15.5 (IQR 3.0), p = 0.026). A range of emulsifiers may influence intestinal inflammation in mice, and dietary restriction of emulsifiers is feasible. Trials investigating the efficacy of a low emulsifier diet in Crohn’s disease are warranted.

Molecular basis of carrageenan-induced cytokines production in macrophages

BACKGROUND

Low molecular weight carrageenan (Cg) is a seaweed-derived sulfated polysaccharide widely used as inflammatory stimulus in preclinical studies. However, the molecular mechanisms of Cg-induced inflammation are not fully elucidated. The present study aimed to investigate the molecular basis involved in Cg-induced macrophages activation and cytokines production.

METHODS

Primary culture of mouse peritoneal macrophages were stimulated with Kappa Cg. The supernatant and cell lysate were used for ELISA, western blotting, immunofluorescence. Cg-induced mouse colitis was also developed.

RESULTS

Here we show that Cg activates peritoneal macrophages to produce pro-inflammatory cytokines such as TNF and IL-1β. While Cg-induced TNF production/secretion depends on TLR4/MyD88 signaling, the production of pro-IL-1β relies on TLR4/TRIF/SYK/reactive oxygen species (ROS) signaling pathway. The maturation of pro-IL1β into IL-1β is dependent on canonical NLRP3 inflammasome activation via Pannexin-1/P2X7/K+ efflux signaling. In vivo, Cg-induced colitis was reduced in mice in the absence of NLRP3 inflammasome components.

CONCLUSIONS

In conclusion, we unravel a critical role of the NLRP3 inflammasome in Cg-induced pro-inflammatory cytokines production and colitis, which is an important discovery on the pro-inflammatory properties of this sulfated polysaccharide for pre-clinical studies. Video abstract Carrageenan (Cg) is one the most used flogistic stimulus in preclinical studies. Nevertheless, the molecular basis of Cg-induced inflammation is not totally elucidated. Herein, Lopes et al. unraveled the molecular basis for Cg-induced macrophages production of biological active IL-1β. The Cg-stimulated macrophages produces pro-IL-1β depends on TLR4/TRIF/Syk/ROS, whereas its processing into mature IL-1β is dependent on the canonical NLRP3 inflammasome.

Attenuation of Inflammatory Symptoms by Icariside B2 in Carrageenan and LPS-Induced Inflammation Models via Regulation of MAPK/NF-κB Signaling Cascades

Prolonged inflammatory responses can lead to the development of several chronic diseases, such as autoimmune disorders and the development of natural therapeutic agents is required. A murine model was used to assess the anti-inflammatory effects of the megastigmane glucoside, icariside B2 (ICSB), and the assessment was carried out in vitro, and in vivo. The in vitro anti-inflammatory effects of ICSB were tested using LPS-stimulated BV2 cells, and the protein expression levels of inflammatory genes and cytokines were assessed. Mice were subcutaneously injected with 1% carrageenan (CA) to induce acute phase inflammation in the paw. Inflammation was assessed by measuring paw volumes hourly; subsequently, the mice were euthanized and the right hind paw skin was expunged and processed for reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses. ICSB inhibits LPS-stimulated nitric oxide (NO) and prostaglandin E2 (PGE₂) generation by reducing the expression of inducible NO synthase (iNOS) and cyclooxygenase 2 (COX-2). ICSB also inhibits the COX-2 enzyme with an IC50 value of 7.80 ± 0.26 µM. Molecular docking analysis revealed that ICSB had a strong binding affinity with both murine and human COX-2 proteins with binding energies of −8 kcal/mol and −7.4 kcal/mol, respectively. ICSB also reduces the manifestation of pro-inflammatory cytokines, such as TNF-α, IL-6, and IL-1β, at their transcriptional and translational level. ICSB hinders inhibitory protein κBα (IκBα) phosphorylation, thereby terminating the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) nuclear translocation. ICSB also represses the mitogen-activated protein kinases (MAPKs) signaling pathways. ICSB (50 mg/kg) showed an anti-edema effect in CA-induced mice and suppressed the CA-induced increases in iNOS and COX-2 protein levels. ICSB attenuated inflammatory responses by downregulating NF-κB expression through interference with extracellular signal-regulated kinase (ERK) and p38 phosphorylation, and by modulating the expression levels of iNOS, COX-2, TNF-α, IL-1β, and IL-6.

Food additive emulsifiers: a review of their role in foods, legislation and classifications, presence in food supply, dietary exposure, and safety assessment

Food additive intakes have increased with the increase in "ultra-processed" food consumption. Food additive emulsifiers have received particular research attention in recent years due to preliminary evidence of adverse gastrointestinal and metabolic health effects. In this review, the use of emulsifiers as food additives is discussed, and the current estimations of exposure to, and safety of, emulsifiers are critically assessed. Food additive emulsifier research is complicated by heterogeneity in additives considered to be emulsifiers and labelling of them on foods globally. Major limitations exist in estimating food additive emulsifier exposure, relating predominantly to a lack of available food occurrence and concentration data. Development of brand-specific food additive emulsifier databases are crucial to accurately estimating emulsifier exposure. Current research on the health effects of food additive emulsifiers are limited to in vitro and murine studies and small, acute studies in humans, and future research should focus on controlled human trials of longer duration.

Carrageenan-Free Diet Shows Improved Glucose Tolerance and Insulin Signaling in Prediabetes: A Randomized, Pilot Clinical Trial

OBJECTIVES

Carrageenan is well known to cause inflammation and is used in laboratory experiments to study mediators and treatments of inflammation. However, carrageenan is added to hundreds of processed foods to improve texture. Previous work indicated that low concentrations of carrageenan in drinking water caused marked glucose intolerance and insulin resistance in a mouse model. This exploratory, clinical study tested the impact of the no-carrageenan diet in prediabetes. Research Design and Methods. Participants with prediabetes (n = 13), defined as HbA1c of 5.7%-6.4%, enrolled in a 12-week, randomized, parallel-arm, feeding trial. One group (n = 8) was provided all meals and snacks with no carrageenan. A second group (n = 5) received a similar diet with equivalent content of protein, fat, and carbohydrate, but with carrageenan. Blood samples were collected at baseline and during oral glucose tolerance tests at 6 and 12 weeks. The primary outcome measure was changed in %HbA1c between baseline and 12 weeks. Statistical analysis included paired and unpaired t-tests, correlations, and 2 × 2 ANOVAs.

RESULTS

Subjects on no carrageenan had declines in HbA1c and HOMA-IR (p = 0.006, p = 0.026; paired t-test, two tailed). They had increases in C-peptide (p = 0.029) and Matsuda Index (2.1 ± 0.7 to 4.8 ± 2.3; p = 0.052) and declines in serum IL-8, serum galectin-3, and neutrophil phospho-(Ser307/312)-IRS1 (p = 0.049, p = 0.003, and p = 0.006; paired t-tests, two tailed). Subjects on the diet with carrageenan had no significant changes in these parameters. Significant differences between no-carrageenan and carrageenan-containing diet groups for changes from baseline to 12 weeks occurred in C-peptide, phospho-Ser-IRS1, phospho-AKT1, and mononuclear cell arylsulfatase B (p = 0.007, p = 0.038, p = 0.0012, and p = 0.0008; 2 × 2 ANOVA). Significant correlations were evident between several of the variables.

CONCLUSIONS

Findings indicate improvement in HbA1c and HOMA-IR in participants on no-carrageenan diets, but not in participants on carrageenan-containing diets. Significant differences between groups suggest that removing carrageenan may improve insulin signaling and glucose tolerance. Larger studies are needed to further consider the impact of carrageenan on development of diabetes.

Human BCL10 Deficiency due to Homozygosity for a Rare Allele

In 2014, a child with broad combined immunodeficiency (CID) who was homozygous for a private BCL10 allele was reported to have complete inherited human BCL10 deficiency. In the present study, we report a new BCL10 mutation in another child with CID who was homozygous for a BCL10 variant (R88X), previously reported as a rare allele in heterozygosis (minor allele frequency, 0.000003986). The mutant allele was a loss-of-expression and loss-of-function allele. As with the previously reported patient, this patient had complete BCL10 deficiency. The clinical phenotype shared features, such as respiratory infections, but differed from that of the previous patient that he did not develop significant gastroenteritis episodes or chronic colitis. Cellular and immunological phenotypes were similar to those of the previous patient. TLR4, TLR2/6, and Dectin-1 responses were found to depend on BCL10 in fibroblasts, and final maturation of T cell and B cell maturation into memory cells was affected. Autosomal-recessive BCL10 deficiency should therefore be considered in children with CID.

Four New Iridoid Metabolites Have Been Isolated from the Stems of Neonauclea reticulata (Havil.) Merr. with Anti-Inflammatory Activities on LPS-Induced RAW264.7 Cells

One new iridoid, namely neonanin C (1) one monocyclic iridoid ring-opened derivative namely neonanin D (2), two new bis-iridoid derivatives namely reticunin A (3) and reticunin B (4) with sixteen known compounds (5-20) were isolated from the stems of Neonauclea reticulata (Havil.) Merr. These new structures were determined by the detailed analysis of spectroscopic data and comparison with the data of known analogues. Compounds 1-20 were evaluated for inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages cell line. The results showed that all compounds exhibited no obvious cytotoxicity compared to the control group and five compounds including isoboonein (7), syringaresinol (10), (+)-medioresinol (12), protocatechuic acid (14) and trans-caffeic acid (15) exhibited inhibitory activities with IC50 values at 86.27 ± 3.45; 9.18 ± 1.90; 76.18 ± 2.42; 72.91 ± 4.97 and 95.16 ± 1.20 µg/mL, respectively.

Reply to critique of "A randomized trial of the effects of the no-carrageenan diet on ulcerative colitis disease activity"

This article is an invited response to a critique by industry of our published study about the impact of carrageenan supplement on the interval to relapse in ulcerative colitis patients on a no-carrageenan diet.

Distinct Effects of Carrageenan and High-Fat Consumption on the Mechanisms of Insulin Resistance in Nonobese and Obese Models of Type 2 Diabetes

Exposure to low concentration of the common food additive carrageenan (10 mg/L) for only six days led to glucose intolerance and insulin resistance in the C57BL/6J mouse. Longer exposure produced fasting hyperglycemia but with no increase in weight, in contrast to the HFD. Glucose intolerance was attributable to carrageenan-induced inflammation and to increased expression of GRB10. Both HFD and carrageenan increased p(Ser32)-IκBα and p(Ser307)-IRS1, and the increases were greater following the combined exposure. The effects of carrageenan were inhibited by the combination of the free radical inhibitor Tempol and BCL10 siRNA, which had no impact on the HFD-mediated increase. In contrast, the PKC inhibitor sotrastaurin blocked the HFD-induced increases, without an effect on the carrageenan-mediated effects. HFD had no impact on the expression of GRB10. Both carrageenan and high fat increased hepatic infiltration by F4/80-positive macrophages. Serum galectin-3 and galectin-3 binding to the insulin receptor increased by carrageenan and by HFD. Tyrosine phosphorylation of the insulin receptor declined following either exposure and was further reduced by their combination. Carrageenan reduced the activity of the enzyme N-acetylgalactosamine-4-sulfatase (ARSB; arylsulfatase B), which was unchanged following HFD. Dietary exposure to both high fat and carrageenan can impair insulin signaling through both similar and distinct mechanisms.

Metabolic effects in mice of cream formulation: Addition of both thickener and emulsifier does not alter lipid metabolism but modulates mucus cells and intestinal endoplasmic reticulum stress

Additives stabilize or improve the organoleptic or functional properties (or both) of many dairy products including whipping cream. Their influence on the metabolic effect of dairy cream is scarcely known. We tested the hypothesis that added emulsifier (lactic acid esters of mono- and diglycerides; MAG/DAG), thickener (carrageenan, CGN), or both, could modify the metabolic effect, notably in the intestine and liver. Nine-week-old male C57Bl/6J mice were fed UHT cream (indirect treatment) mixed with nonlipidic powder (final: 13% milkfat) for 1 or 4 wk. We compared creams (1) without additive (Ctl), (2) with thickener (Th), 0.02% of κ-CGN, and (3) with both thickener and emulsifier, 0.1% of MAG/DAG esters (Th/Em). We analyzed plasma parameters, intestine, and liver. Fasting glycemia, insulinemia, triglyceridemia, nonesterified fatty acids, body weight gain, and liver weight did not differ among groups. After 1 wk, Th/Em had higher expression in the duodenum of some of the genes involved in (1) intestinal lipid absorption and (2) tight junction proteins versus Ctl and Th. After 4 wk, mucus cell number in the small intestine was higher in Th/Em versus Ctl and Th. Genes involved in endoplasmic reticulum (ER) stress in the duodenum were more expressed in Th/Em after 1 wk. After 4 wk, in the colon, a higher expression of ER stress genes was observed for Th versus Th/Em and Ctl. Liver damage score was not altered by additives. Adding both CGN (0.02%) and MAG/DAG esters (0.1%) in dairy cream did not result in deleterious outcomes in mice after 4 wk regarding lipid metabolism, intestinal permeability, and liver disorders. The longer term effect of intestinal ER stress modulation deserves further investigation.

Growth hormone-releasing hormone antagonists reduce prostatic enlargement and inflammation in carrageenan-induced chronic prostatitis

BACKGROUND

Inflammation plays a key role in the etiology of benign prostatic hyperplasia (BPH) through multiple pathways involving the stimulation of proliferation by cytokines and growth factors as well as the induction of the focal occurrence of epithelial-to-mesenchymal transition (EMT). We have previously reported that GHRH acts as a prostatic growth factor in experimental BPH and in autoimmune prostatitis models and its blockade with GHRH antagonists offer therapeutic approaches for these conditions. Our current study was aimed at the investigation of the beneficial effects of GHRH antagonists in λ-carrageenan-induced chronic prostatitis and at probing the downstream molecular pathways that are implicated in GHRH signaling.

METHODS

To demonstrate the complications triggered by recurrent/chronic prostatic inflammation in Sprague-Dawley rats, 50 μL 3% carrageenan was injected into both ventral prostate lobes two times, 3 weeks apart. GHRH antagonist, MIA-690, was administered 5 days after the second intraprostatic injection at 20 μg daily dose for 4 weeks. GHRH-induced signaling events were identified in BPH-1 and in primary prostate epithelial (PrEp) cells at 5, 15, 30, and 60 min with Western blot.

RESULTS

Inflammation induced prostatic enlargement and increased the area of the stromal compartment whereas treatment with the GHRH antagonist significantly reduced these effects. This beneficial activity was consistent with a decrease in prostatic GHRH, inflammatory marker COX-2, growth factor IGF-1 and inflammatory and EMT marker TGF-β1 protein levels and the expression of multiple genes related to EMT. In vitro, GHRH stimulated multiple pathways involved in inflammation and growth in both BPH-1 and PrEp cells including NFκB p65, AKT, ERK1/2, EGFR, STAT3 and increased the levels of TGF-β1 and Snail/Slug. Most interestingly, GHRH also stimulated the transactivation of the IGF receptor.

CONCLUSIONS

The study demonstrates that GHRH antagonists could be beneficial for the treatment of prostatic inflammation and BPH in part by inhibiting the growth-promoting and inflammatory effects of locally produced GHRH.

Attenuation of inflammatory responses by (+)-syringaresinol via MAP-Kinase-mediated suppression of NF-κB signaling in vitro and in vivo

We examined the anti-inflammatory effects of (+)-syringaresinol (SGRS), a lignan isolated from Rubia philippinensis, in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells using enzyme-based immuno assay, Western blotting, and RT-PCR analyses. Additionally, in vivo effects of SGRS in the acute inflammatory state were examined by using the carrageenan-induced hind paw edema assay in experimental mice. As a result, treatment with SGRS (25, 50, and 100 μM) inhibited protein expression of lipopolysaccharide-stimulated inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor kappa B (NF-κB) as well as production of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and interleukin-6 (IL-6) induced by LPS. Moreover, SGRS also reduced LPS-induced mRNA expression levels of iNOS and COX-2, including NO, PGE2, TNF-α, IL-1β, and IL-6 cytokines in a dose-dependent fashion. Furthermore, carrageenan-induced paw edema assay validated the in vivo anti-edema effect of SGRS. Interestingly, SGRS (30 mg/kg) suppressed carrageenan-induced elevation of iNOS, COX-2, TNF-α, IL-1β, and IL-6 mRNA levels as well as COX-2 and NF-κB protein levels, suggesting SGRS may possess anti-inflammatory activities.

Amelioration of inflammatory responses by Socheongryong-Tang, a traditional herbal medicine, in RAW 264.7 cells and rats

Socheongryong-Tang (SCRT) is a natural medicine prescription that has been mainly used in East Asia for the treatment of inflammatory disorders, including asthma and allergic rhinitis. The present study evaluated the anti-inflammatory effects of SCRT on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and in a rat model of carrageenan (CA)-induced paw edema. Levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and prostaglandin E2 (PGE2) in the culture supernatant were quantified and nitric oxide (NO) production was monitored. In addition, the effect of SCRT on the protein expression of nuclear factor-κB (NF-κB), mitogen-activated protein kinases (MAPKs), inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) was assessed by western blot analysis. Furthermore, the effects of SCRT on acute inflammation in vivo and changes in the histomorphometry and histopathology of paw skin were observed using CA-treated rats. SCRT (1 mg/ml) inhibited the LPS-induced changes in the protein expression of NF-κB, JNK, ERK1/2, iNOS and COX-2, as well as the production of NO, PGE2 and cytokines. In the rat paw edema assay, administration of 1 g/kg of lyophilized powder obtained from the aqueous extracts of SCRT for 3 consecutive days inhibited the CA-induced increases in skin thickness, mast cell degranulation, and infiltration of inflammatory cells in the ventral and dorsal pedis skin within 4 h. These results demonstrated that SCRT exerts its anti-inflammatory activities in LPS-stimulated RAW 264.7 cells through decreasing the production of inflammatory mediators, including PGE2, NO and cytokines, via suppression of the NF-κB and JNK and ERK1/2 signaling pathways. In addition, the data of the CA-induced paw edema indicated an anti-edema effect of SCRT. SCRT (1 g/kg) reduced acute edematous inflammation through inhibition of mast cell degranulation and infiltration of inflammatory cells. Therefore, the present study provided scientific evidence for the anti-inflammatory activities of SCRT as well as the underlying mechanisms.

Re-evaluation of carrageenan (E 407) and processed Eucheuma seaweed (E 407a) as food additives

The present opinion deals with the re-evaluation of the safety of food-grade carrageenan (E 407) and processes Eucheuma seaweed (E 407a) used as food additives. Because of the structural similarities, the Panel concluded that processed Eucheuma seaweed can be included in the evaluation of food-grade carrageenan. Poligeenan (average molecular weight 10-20 kDa) has not been authorised as a food additive and is not used in any food applications. In its evaluation of carrageenan (E 407) and processed Eucheuma seaweed (E 407a), the Panel noted that the ADME database was sufficient to conclude that carrageenan was not absorbed intact; in a subchronic toxicity study performed with carrageenan almost complying with the EU specification for E 407 in rats, the no-observed-adverse-effect level (NOAEL) was 3,400-3,900 mg/kg body weight (bw) per day, the highest dose tested; no adverse effects have been detected in chronic toxicity studies with carrageenan in rats up to 7,500 mg/kg bw per day, the highest dose tested; there was no concern with respect to the carcinogenicity of carrageenan; carrageenan and processed Eucheuma seaweed did not raise a concern with respect to genotoxicity; the NOAEL of sodium and calcium carrageenan for prenatal developmental dietary toxicity studies were the highest dose tested; the safety of processed Eucheuma seaweed was sufficiently covered by the toxicological evaluation of carrageenan; data were adequate for a refined exposure assessment for 41 out of 79 food categories. However, the Panel noted uncertainties as regards the chemistry, the exposure assessment and biological and toxicological data. Overall, taking into account the lack of adequate data to address these uncertainties, the Panel concluded that the existing group acceptable daily intake (ADI) for carrageenan (E 407) and processed Eucheuma seaweed (E 407a) of 75 mg/kg bw per day should be considered temporary, while the database should be improved within 5 years after publication of this opinion.

Evaluation of the anti-inflammatory effect of an anti-platelet agent crinumin on carrageenan-induced paw oedema and granuloma tissue formation in rats

The present study was designed to explore the anti-inflammatory activity of an anti-platelet agent crinumin, by various in vitro and in vivo inflammation models. Firstly, crinumin protein was purified through cation exchange chromatography; then, in vitro activity was estimated by albumin denaturation assay and HRBC membrane stabilization assay. Carrageenan-induced paw oedema and cotton pellet-induced granuloma models were used for in vivo anti-inflammatory activity assessment in rats. In both models, rats were pre-treated for 7 days with crinumin (25-50 µg/ml) and diclofenac sodium (50 µg/ml). Expression of P-selectin (in serum and plasma) through ELISA and NF-κB (in paw and granulomatous tissues) through western blotting was checked. Our results showed that crinumin at both doses (25 or 50 µg/kg of b.w.) significantly (p < 0.05) reduced the paw oedema formation in a dose-dependent manner in the second phase of inflammation and significant (p < 0.05) reduction of wet and dry weight of granuloma was observed indicating the anti-inflammatory potential of crinumin. Crinumin decreased the expression of P-selectin and NF-κB indicating its potential role in decreasing platelet activation and healing inflammation. Histopathological studies additionally proved the efficacy of drug in treating inflammation. The results of the study suggest that the crinumin might have an inhibitory role in atherosclerosis as platelet aggregation and inflammation are the key processes involved in atherosclerotic disorders.

A randomized trial of the effects of the no-carrageenan diet on ulcerative colitis disease activity

BACKGROUND: Carrageenan is a very common food additive in Western diets, but predictably causes inflammation in thousands of cell-based and animal experiments.

OBJECTIVE: To assess the impact of carrageenan exposure on the interval to relapse in patients with ulcerative colitis in remission.

METHODS: A randomized, double-blind, placebo-controlled, multicenter, clinical trial was conducted to assess if patients with ulcerative colitis in remission would have a longer interval to relapse if they followed a diet with no carrageenan. All participants were instructed in the no-carrageenan diet and were randomized to either placebo capsules or carrageenan-containing capsules. The carrageenan in the capsules was less than the average daily carrageenan intake from the diet. Relapse was defined as an increase of two or more points on the Simple Clinical Colitis Activity Index (SCCAI) and intensification of treatment for ulcerative colitis. Participants were followed by telephone calls every two weeks until relapse or one year of participation. The occurrence of relapse and inflammatory biomarkers were compared between the two groups.

RESULTS: Twelve patients completed study questionnaires. Three patients who received carrageenan-containing capsules relapsed, and none of the patients who received placebo-containing capsules relapsed (p = 0.046, log-rank test). Laboratory tests showed increases in Interleukin-6 (p = 0.02, paired t-test, two-tailed) and fecal calprotectin (p = 0.06; paired t-test, two-tailed) between the beginning and the end of study participation in the carrageenan-exposed group, but not in the placebo-group.

CONCLUSION: Carrageenan intake contributed to earlier relapse in patients with ulcerative colitis in remission. Restriction of dietary carrageenan may benefit patients with ulcerative colitis.

Zinc rescues obesity-induced cardiac hypertrophy via stimulating metallothionein to suppress oxidative stress-activated BCL10/CARD9/p38 MAPK pathway

Obesity often leads to obesity-related cardiac hypertrophy (ORCH), which is suppressed by zinc-induced inactivation of p38 mitogen-activated protein kinase (p38 MAPK). In this study, we investigated the mechanisms by which zinc inactivates p38 MAPK to prevent ORCH. Mice (4-week old) were fed either high fat diet (HFD, 60% kcal fat) or normal diet (ND, 10% kcal fat) containing variable amounts of zinc (deficiency, normal and supplement) for 3 and 6 months. P38 MAPK siRNA and the p38 MAPK inhibitor SB203580 were used to suppress p38 MAPK activity in vitro and in vivo, respectively. HFD activated p38 MAPK and increased expression of B-cell lymphoma/CLL 10 (BCL10) and caspase recruitment domain family member 9 (CARD9). These responses were enhanced by zinc deficiency and attenuated by zinc supplement. Administration of SB203580 to HFD mice or specific siRNA in palmitate-treated cardiomyocytes eliminated the HFD and zinc deficiency activation of p38 MAPK, but did not significantly impact the expression of BCL10 and CARD9. In cultured cardiomyocytes, inhibition of BCL10 expression by siRNA prevented palmitate-induced increased p38 MAPK activation and atrial natriuretic peptide (ANP) expression. In contrast, inhibition of p38 MAPK prevented ANP expression, but did not affect BCL10 expression. Deletion of metallothionein abolished the protective effect of zinc on palmitate-induced up-regulation of BCL10 and phospho-p38 MAPK. HFD and zinc deficiency synergistically induce ORCH by increasing oxidative stress-mediated activation of BCL10/CARD9/p38 MAPK signalling. Zinc supplement ameliorates ORCH through activation of metallothionein to repress oxidative stress-activated BCL10 expression and p38 MAPK activation.

κ-Carrageenan Enhances Lipopolysaccharide-Induced Interleukin-8 Secretion by Stimulating the Bcl10-NF-κB Pathway in HT-29 Cells and Aggravates C. freundii-Induced Inflammation in Mice

Background. The dietary usage of carrageenan as common food additive has increased observably over the last 50 years. But there is substantial controversy about its safety. Methods. We investigated whether the κ-carrageenan could enhance lipopolysaccharide-induced IL-8 expression by studying its actions on the TLR4-NF-κB pathway. The aggravating effect of κ-carrageenan on Citrobacter freundii DBS100-induced intestinal inflammation was also investigated in a mouse model. Results. Our data show that κ-carrageenan pretreatment promoted LPS-induced IL-8 expression in HT-29 cells. Although CD14, MD-2, and TLR4 were upregulated, the binding of LPS was not enhanced. However, the pathway of Bcl10-NF-κB was triggered. Interestingly, κ-carrageenan competitively blocked the binding of FITC-LPS. Furthermore, pretreatment with κ-carrageenan for one week previous to gavage with C. freundii DBS100 markedly aggravated weight loss, mortality, and colonic damage. The secretion of cytokines was unbalanced and the ratio of Tregs was decreased significantly. In addition, κ-carrageenan, together with C. freundii DBS100, enhanced the transcription and secretion of TLR4 and NF-κB. Conclusions. κ-Carrageenan can synergistically activate LPS-induced inflammatory through the Bcl10-NF-κB pathway, as indicated by its aggravation of C. freundii DBS100-induced colitis in mice. General Significance. Our results suggest that κ-carrageenan serves as a potential inflammatory agent that magnifies existing intestinal inflammation.

The Role of Carrageenan and Carboxymethylcellulose in the Development of Intestinal Inflammation

Although the exact pathophysiology remains unknown, the development of inflammatory bowel disease (IBD) is influenced by the interplay between genetics, the immune system, and environmental factors such as diet. The commonly used food additives, carrageenan and carboxymethylcellulose (CMC), are used to develop intestinal inflammation in animal models. These food additives are excluded from current dietary approaches to induce disease remission in Crohn's disease such as exclusive enteral nutrition (EEN) using a polymeric formula. By reviewing the existing scientific literature, this review aims to discuss the role that carrageenan and CMC may play in the development of IBD. Animal studies consistently report that carrageenan and CMC induce histopathological features that are typical of IBD while altering the microbiome, disrupting the intestinal epithelial barrier, inhibiting proteins that provide protection against microorganisms, and stimulating the elaboration of pro-inflammatory cytokines. Similar trials directly assessing the influence of carrageenan and CMC in humans are of course unethical to conduct, but recent studies of human epithelial cells and the human microbiome support the findings from animal studies. Carrageenan and CMC may trigger or magnify an inflammatory response in the human intestine but are unlikely to be identified as the sole environmental factor involved in the development of IBD or in disease recurrence after treatment. However, the widespread use of carrageenan and CMC in foods consumed by the pediatric population in a "Western" diet is on the rise alongside a corresponding increase in IBD incidence, and questions are being raised about the safety of frequent usage of these food additives. Therefore, further research is warranted to elucidate the role of carrageenan and CMC in intestinal inflammation, which may help identify novel nutritional strategies that hinder the development of the disease or prevent disease relapse post-EEN treatment.

Mucosal Interactions between Genetics, Diet, and Microbiome in Inflammatory Bowel Disease

Numerous reviews have discussed gut microbiota composition changes during inflammatory bowel diseases (IBD), particularly Crohn’s disease (CD). However, most studies address the observed effects by focusing on studying the univariate connection between disease and dietary-induced alterations to gut microbiota composition. The possibility that these effects may reflect a number of other interconnected (i.e., pantropic) mechanisms, activated in parallel, particularly concerning various bacterial metabolites, is in the process of being elucidated. Progress seems, however, hampered by various difficult-to-study factors interacting at the mucosal level. Here, we highlight some of such factors that merit consideration, namely: (1) the contribution of host genetics and diet in altering gut microbiome, and in turn, the crosstalk among secondary metabolic pathways; (2) the interdependence between the amount of dietary fat, the fatty acid composition, the effects of timing and route of administration on gut microbiota community, and the impact of microbiota-derived fatty acids; (3) the effect of diet on bile acid composition, and the modulator role of bile acids on the gut microbiota; (4) the impact of endogenous and exogenous intestinal micronutrients and metabolites; and (5) the need to consider food associated toxins and chemicals, which can introduce confounding immune modulating elements (e.g., antioxidant and phytochemicals in oils and proteins). These concepts, which are not mutually exclusive, are herein illustrated paying special emphasis on physiologically inter-related processes.

Synergistic effect of κ-carrageenan on oxazolone-induced inflammation in BALB/c mice

Background

Carrageenan is a traditional ingredient that has been widely used in the food industry. In the present study, we propose a hypothesis that carrageenan is a conditional inflammatory agent. When the intestinal tract is in an “unhealthy” state such as that during bacterial infection or acute inflammation, carrageenan can synergistically enhance the inflammatory response.

Methods

BALB/C mice received κ-carrageenan via intragastric administration prior to the induction of oxazolone colitis. Weight changes, survival rate, histologic change, secretion of inflammatory cytokines, ratio of regulatory T cells (Tregs) in peripheral blood, and expression of genes and proteins involved in inflammation and cell proliferation in the colonic mucosa were examined.

Results

Intragastric administration of κ-carrageenan to BALB/c mice prior to the induction of oxazolone colitis resulted in an aggravation of body weight loss, a decrease in the survival ratio, aggravation of colonic inflammation, and decrease in the ratio of CD4 + CD25+/CD4+. The secretion of interleukin-4 (IL-4), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) also significantly increased after κ-carrageenan administration. κ-Carrageenan, together with oxazolone, suppressed the expression of forkhead box p3 (FOXp3) and increased the expression of Toll-like receptor 4 (TLR4), Nuclear factor-κB (NF-κB), and proliferating cell nuclear antigen in the colonic mucosa. These results were confirmed by qRT-PCR and western blot analyses at the molecular and protein levels, respectively.

Conclusions

κ-Carrageenan aggravated oxazolone-induced intestinal inflammation in BALB/c mice. This effect is associated with an activation of the TLR4-NF-κB pathway, a decreased ratio of Tregs, and the induction of Th2-dependent immune responses.

Phenome-driven disease genetics prediction toward drug discovery

MOTIVATION

Discerning genetic contributions to diseases not only enhances our understanding of disease mechanisms, but also leads to translational opportunities for drug discovery. Recent computational approaches incorporate disease phenotypic similarities to improve the prediction power of disease gene discovery. However, most current studies used only one data source of human disease phenotype. We present an innovative and generic strategy for combining multiple different data sources of human disease phenotype and predicting disease-associated genes from integrated phenotypic and genomic data.

RESULTS

To demonstrate our approach, we explored a new phenotype database from biomedical ontologies and constructed Disease Manifestation Network (DMN). We combined DMN with mimMiner, which was a widely used phenotype database in disease gene prediction studies. Our approach achieved significantly improved performance over a baseline method, which used only one phenotype data source. In the leave-one-out cross-validation and de novo gene prediction analysis, our approach achieved the area under the curves of 90.7% and 90.3%, which are significantly higher than 84.2% (P < e(-4)) and 81.3% (P < e(-12)) for the baseline approach. We further demonstrated that our predicted genes have the translational potential in drug discovery. We used Crohn's disease as an example and ranked the candidate drugs based on the rank of drug targets. Our gene prediction approach prioritized druggable genes that are likely to be associated with Crohn's disease pathogenesis, and our rank of candidate drugs successfully prioritized the Food and Drug Administration-approved drugs for Crohn's disease. We also found literature evidence to support a number of drugs among the top 200 candidates. In summary, we demonstrated that a novel strategy combining unique disease phenotype data with system approaches can lead to rapid drug discovery.

AVAILABILITY AND IMPLEMENTATION

nlp.

CASE

edu/public/data/DMN

Hederagenin, a major component of Clematis mandshurica Ruprecht root, attenuates inflammatory responses in RAW 264.7 cells and in mice

Clematis mandshurica Ruprecht root has been used in Asia as a traditional anti-inflammatory, analgesic, and antitumor agent. Its main active component is hederagenin, a naturally occurring triterpene, and in this study, we examined the anti-inflammatory effects of hederagenin in lipopolysaccharide-stimulated RAW 264.7 cells using an enzyme-linked immunosorbent assay, Western blot, and RT-PCR. In addition, its effects on acute inflammation in vivo were observed using a carrageenan-induced mouse hind paw edema assay. Furthermore, the changes on the histopathology and histomorphometry of hind paw skins were examined using carrageenan-treated mice. Treatment with hederagenin (10, 30 and 100μM) resulted in inhibited levels of protein expression of lipopolysaccharide-stimulated iNOS, COX-2, and NF-κB as well as production of NO, PGE2, TNF-α, IL-1β, and IL-6 induced by lipopolysaccharide. Consistent with these results, hederagenin also dose-dependently reduced the lipopolysaccharide-induced mRNA levels of iNOS and COX-2, and of the above-mentioned cytokines. Interestingly, results of the carrageenan-induced mouse hind paw edema assay showed an anti-edema effect of hederagenin. Furthermore, hederagenin (30mg/kg) inhibited the carrageenan-induced increases in skin thicknesses, infiltrated inflammatory cells, and mast cell degranulation. These results suggest that hederagenin may possess anti-inflammatory activities.