Trends in 3D models of inflammatory bowel disease

Inflammatory bowel disease (IBD) encompasses a set of chronic inflammatory conditions, namely Crohn's disease and ulcerative colitis. Despite all advances in the management of IBD, a definitive cure is not available, largely due to a lack of a holistic understanding of its etiology and pathophysiology. Several in vitro, in vivo, and ex vivo models have been developed over the past few decades in order to abbreviate remaining gaps. The establishment of reliable and predictable in vitro intestinal inflammation models may indeed provide valuable tools to expedite and validate the development of therapies for IBD. Three-dimensional (3D) models provide a more accurate representation of the different layers of the intestine, contributing to a stronger impact on drug screening and research on intestinal inflammation, and bridging the gap between in vitro and in vivo research. This work provides a critical overview on the state-of-the-art on existing 3D models of intestinal inflammation and discusses the remaining challenges, providing insights on possible pathways towards achieving IBD mimetic models. We also address some of the main challenges faced by implementing cell culture models in IBD research while bearing in mind clinical translational aspects.

Effect of Digested Selected Food Items on Markers of Oxidative Stress and Inflammation in a Caco-2-Based Human Gut Epithelial Model

The human gut epithelium presents a crucial interface between ingested food items and the host. Understanding how different food items influence oxidative stress and inflammation in the gut is of great importance. This study assessed the impact of various digested food items on oxidative stress, inflammation, and DNA/RNA damage in human gut epithelial cells. Differentiated Caco-2 cells were exposed to food items and their combinations (n = 22) selected from a previous study, including sausage, white chocolate, soda, coffee, orange juice, and curcumin. Following stimulation with TNF-α/IFN-1β/LPS and H2O2 for 4 h, the cells were exposed to digested food items or appropriate controls (empty digesta and medium) for a further 16 h. Cell viability, antioxidant capacity (ABTS, FRAP), IL-6, IL-8, F2-isoprostanes, lipid peroxidation (MDA), and DNA/RNA oxidative damage were assessed (3 independent triplicates). The ABTS assay revealed that cells treated with "white chocolate" and "sausage + coffee" exhibited significantly reduced antioxidant capacity compared to stimulated control cells (ABTS = 52.3%, 54.8%, respectively, p < 0.05). Similar results were observed for FRAP (sausage = 34.9%; white chocolate + sausage = 35.1%). IL-6 levels increased in cells treated with "white chocolate + sausage" digesta (by 101%, p < 0.05). Moreover, MDA levels were significantly elevated in cells treated with digested "sausage" or sausage in combination with other food items. DNA/RNA oxidative damage was found to be higher in digesta containing sausage or white chocolate (up to 550%, p < 0.05) compared to stimulated control cells. This investigation provides insights into how different food items may affect gut health and underscores the complex interplay between food components and the epithelium at this critical interface of absorption.

Carotenoids in Health as Studied by Omics-Related Endpoints

Carotenoids have been associated with risk reduction for several chronic diseases, including the association of their dietary intake/circulating levels with reduced incidence of obesity, type 2 diabetes, certain types of cancer, and even lower total mortality. In addition to some carotenoids constituting vitamin A precursors, they are implicated in potential antioxidant effects and pathways related to inflammation and oxidative stress, including transcription factors such as nuclear factor κB and nuclear factor erythroid 2-related factor 2. Carotenoids and metabolites may also interact with nuclear receptors, mainly retinoic acid receptor/retinoid X receptor and peroxisome proliferator-activated receptors, which play a role in the immune system and cellular differentiation. Therefore, a large number of downstream targets are likely influenced by carotenoids, including but not limited to genes and proteins implicated in oxidative stress and inflammation, antioxidation, and cellular differentiation processes. Furthermore, recent studies also propose an association between carotenoid intake and gut microbiota. While all these endpoints could be individually assessed, a more complete/integrative way to determine a multitude of health-related aspects of carotenoids includes (multi)omics-related techniques, especially transcriptomics, proteomics, lipidomics, and metabolomics, as well as metagenomics, measured in a variety of biospecimens including plasma, urine, stool, white blood cells, or other tissue cellular extracts. In this review, we highlight the use of omics technologies to assess health-related effects of carotenoids in mammalian organisms and models.

Deoxynivalenol increases pro-inflammatory cytokine secretion and reduces primary bile acid transport in an inflamed intestinal in vitro co-culture model

The fungal secondary metabolite deoxynivalenol (DON) that can contaminate cereal-based food products not only induces inflammation but also reduces bile acid absorption by a healthy human intestine. Bile acid malabsorption is commonly observed in individuals with an inflamed intestine. Here we studied the effects of DON on inflammation and primary bile acid transport using an in vitro model for an inflamed intestine. An inflamed intestinal in vitro model was established by co-culturing a Caco-2 cell-layer and LPS-pre-stimulated THP-1 macrophages in Transwells. We observed a decreased transport of 5 primary bile acids across inflamed co-cultures compared to healthy co-cultures but not of chenodeoxycholic acid. DON exposure further reduced the transport of the affected primary bile acids across the inflamed co-cultures. DON exposure also enhanced the secretion of pro-inflammatory cytokines in the inflamed co-cultures, while it did not increase the pro-inflammatory cytokines secretion from LPS-pre-stimulated THP-1 monocultures. Exposure of Caco-2 cell-layers to pro-inflammatory cytokines or THP-1 conditioned media partly mimicked the DON-induced effects of the co-culture model. Local activation of intestinal immune cells reinforces the direct pro-inflammatory effects of DON on intestinal epithelial cells. This affects the bile acid intestinal kinetics in an inflamed intestine.

Optimizing THP-1 Macrophage Culture for an Immune-Responsive Human Intestinal Model

Previously established immune-responsive co-culture models with macrophages have limitations due to the dedifferentiation of macrophages in long-term cultures. This study is the first report of a long-term (21-day) triple co-culture of THP-1 macrophages (THP-1m) with Caco-2 intestinal epithelial cells and HT-29-methotrexate (MTX) goblet cells. We demonstrated that high-density seeded THP-1 cells treated with 100 ng/mL phorbol 12-myristate 13-acetate for 48 h differentiated stably and could be cultured for up to 21 days. THP-1m were identified by their adherent morphology and lysosome expansion. In the triple co-culture immune-responsive model, cytokine secretions during lipopolysaccharide-induced inflammation were confirmed. Tumor necrosis factor-alpha and interleukin 6 levels were elevated in the inflamed state, reaching 824.7 ± 130.0 pg/mL and 609.7 ± 139.5 pg/mL, respectively. Intestinal membrane integrity was maintained with a transepithelial electrical resistance value of 336.4 ± 18.0 Ω·cm². Overall, our findings suggest that THP-1m can be effectively employed in models of long-term immune responses in both normal and chronic inflammatory states of the intestinal epithelium, making them a valuable tool for future research on the association between the immune system and gut health.

Development of an Inflammation-Triggered In Vitro "Leaky Gut" Model Using Caco-2/HT29-MTX-E12 Combined with Macrophage-like THP-1 Cells or Primary Human-Derived Macrophages

The "leaky gut" syndrome describes a damaged (leaky) intestinal mucosa and is considered a serious contributor to numerous chronic diseases. Chronic inflammatory bowel diseases (IBD) are particularly associated with the "leaky gut" syndrome, but also allergies, autoimmune diseases or neurological disorders. We developed a complex in vitro inflammation-triggered triple-culture model using 21-day-differentiated human intestinal Caco-2 epithelial cells and HT29-MTX-E12 mucus-producing goblet cells (90:10 ratio) in close contact with differentiated human macrophage-like THP-1 cells or primary monocyte-derived macrophages from human peripheral blood. Upon an inflammatory stimulus, the characteristics of a "leaky gut" became evident: a significant loss of intestinal cell integrity in terms of decreased transepithelial/transendothelial electrical resistance (TEER), as well as a loss of tight junction proteins. The cell permeability for FITC-dextran 4 kDa was then increased, and key pro-inflammatory cytokines, including TNF-alpha and IL-6, were substantially released. Whereas in the M1 macrophage-like THP-1 co-culture model, we could not detect the release of IL-23, which plays a crucial regulatory role in IBD, this cytokine was clearly detected when using primary human M1 macrophages instead. In conclusion, we provide an advanced human in vitro model that could be useful for screening and evaluating therapeutic drugs for IBD treatment, including potential IL-23 inhibitors.

Potential of natural products in combination with arsenic trioxide: Investigating cardioprotective effects and mechanisms

Over the past few decades, clinical trials conducted worldwide have demonstrated the efficacy of arsenic trioxide (ATO) in the treatment of relapsed acute promyelocytic leukemia (APL). Currently, ATO has become the frontline treatments for patients with APL. However, its therapeutic applicability is severely constrained by ATO-induced cardiac side effects. Any cardioprotective agents that can ameliorate the cardiac side effects and allow exploiting the full therapeutic potential of ATO, undoubtedly gain significant attention. The knowledge and use of natural products for evidence-based therapy have grown rapidly in recent years. Here we discussed the potential mechanism of ATO-induced cardiac side effects and reviewed the studies on cardiac side effects as well as the research history of ATO in the treatment of APL. Then, We summarized the protective effects and underlying mechanisms of natural products in the treatment of ATO-induced cardiac side effects. Based on the efficacy and safety of the natural product, it has a promising future in the development of cardioprotective agents against ATO-induced cardiac side effects.

Complexification of In Vitro Models of Intestinal Barriers, A True Challenge for a More Accurate Alternative Approach

The use of cell models is common to mimic cellular and molecular events in interaction with their environment. In the case of the gut, the existing models are of particular interest to evaluate food, toxicants, or drug effects on the mucosa. To have the most accurate model, cell diversity and the complexity of the interactions must be considered. Existing models range from single-cell cultures of absorptive cells to more complex combinations of two or more cell types. This work describes the existing solutions and the challenges that remain to be solved.

Potential health effects of brewers' spent grain as a functional food ingredient assessed by markers of oxidative stress and inflammation following gastro-intestinal digestion and in a cell model of the small intestine

Brewer's spent grains (BSG) are a by-product of the beer-brewing industry, often employed as animal feeding stuffs. With BSG being rich not only in proteins, lipids, and dietary fiber but also in certain phytochemicals, it constitutes a potentially valuable food source that could be employed as a functional food, e.g. against chronic inflammatory diseases. Several types of bread were prepared with various amounts of BSG as flour replacement (0, 10, 20, 40, 60, 80 and 100%), either employing wet BSG or dried BSG after pressing. Total phenolics, flavonoids, insoluble dietary fiber, as well as antioxidant capacity (FRAP, ABTS) were measured in the bread, before and after simulated gastro-intestinal digestion. Furthermore, we investigated digested BSG and bread-containing BSG for their capability to alter oxidative stress (Nrf2, malondialdehyde) and inflammation (IL-6, IL-8, NO, and PGE2) in a Caco-2 cell culture model of the small intestine. Incorporation of BSG significantly and dose-dependently enhanced the amount of dietary fiber in the product, as well as total phenolics, flavonoids, and antioxidant capacity, by over 10-fold, 3-fold, 4-fold and 5-fold, respectively, when replacing all of the flour with BSG. This pattern remained after in vitro digestion. However, digesta failed to show significant antioxidant or anti-inflammatory effects on the biomarkers observed in the cell model. Consuming 150 g of such a BSG-bread (wet based) would supply the proposed RDA of 25 g d^-1 dietary fiber and could be a healthy product valorizing BSG.

Citral mitigates inflammation of Caco-2 cells induced by Cronobacter sakazakii

The aim of this study was to explore the anti-inflammatory effect and mechanism of citral in Cronobacter sakazakii-stimulated Caco-2 cells. Safe doses of citral were first determined in Caco-2 cells....

Senegalia macrostachya seed polysaccharides attenuate inflammation-induced intestinal epithelial barrier dysfunction in a Caco-2 and RAW264.7 macrophage co-culture model by inhibiting the NF-κB/MLCK pathway

Senegalia macrostachya seed polysaccharides improved the Caco-2 cell monolayer integrity from the inflammatory insult. SMSP2 treatment lowered the inflammatory cytokine release, increased TJ proteins, and downregulated the NF-κB/MLCK pathway.

pH/ROS dual-sensitive and chondroitin sulfate wrapped poly (β-amino ester)-SA-PAPE copolymer nanoparticles for macrophage-targeted oral therapy for ulcerative colitis

An oral nanoparticle (NPs) encapsulated in chitosan/alginate hydrogel (CA-Gel) with dual-sensitive in pH and reactive oxygen species (ROS) was developed to load curcumin (CUR) based on the intracellular-specific characteristics of macrophages. Chondroitin sulfate (CS) wrapped PBAE-SA-PAPE with intracellular pH/ROS dual-sensitive characteristics and CUR via a simple nanoprecipitation method to form NPs (CS-CUR-NPs), and mixed CA-Gel to acquire the final preparation (CS-CUR-NPs-Gel). CS-CUR-NPs displayed an ideal average particle size (179.19±5.61nm) and high encapsulating efficiency (94.74±1.15%). CS showed a good targeting ability on macrophages and the CA-Gel contribution in protecting NPs from being destroyed in the upper gastrointestinal tract. As expected, CS-CUR-NPs-Gel could significantly alleviate inflammation in DSS-induced UC mice via TLR4-MAPK/NF-κB pathway. This study is the first to attempt to design a novel pH/ROS dual-stimulated release strategy in helping intracellular CUR delivery and anticipated for efficient anti-UC therapy.

Aminocellulose - grafted polycaprolactone-coated core-shell nanoparticles alleviate the severity of ulcerative colitis: a novel adjuvant therapeutic approach

Ulcerative colitis (UC) is an idiopathic inflammatory condition of colorectal regions. Existing therapies for UC face grave lacunae including off-target and other harmful side effects, extensive first-pass metabolism, rapid clearance, limited or poor drug absorption and various other limitations, resulting in lower bioavailability. These conditions demand advanced delivery strategies to inflammatory colonic conditions so that drugs can counter stomach acid, avail protective strategies at this pH and selectively deliver drugs to the colon. Therefore, this approach was undertaken to develop and characterize nanoparticles for the delivery of drugs glycyrrhizic acid as well as budesonide in UC. Biocompatible and biodegradable aminocellulose-conjugated polycaprolactone containing budesonide was covered onto gelatinous nanoparticles (NPs) loaded with GA. Nanoparticles were prepared by the solvent evaporation technique, which showed particle size of ∼230 nm, spherical shape, almost smooth morphological characters under transmission, scanning and atomic force microscopy. These NPs also improved disease activities like occult blood in the stool, length of the colon and fecal properties. The nanoparticle therapy appreciably decreased colonic mast cellular infiltration, significantly maintained mucin protection, ameliorated histological features of the colon. Furthermore, markers of inflammation such as iNOS, COX-2, IL1-β, TNF-α, NO, and MPO were also appreciably ameliorated with the therapy of dual drug-loaded nanoparticles. Overall, these results establish that dual drug-loaded core-shell NPs exhibit superior therapeutic properties over the free or naïve forms of GA and budesonide in acute colon inflammation and present advantages that may be assigned to their ability to significantly inhibit colon inflammatory conditions.

Impact of Protein-Enriched Plant Food Items on the Bioaccessibility and Cellular Uptake of Carotenoids

Carotenoids are lipophilic pigments which have been associated with a number of health benefits, partly related to antioxidant effects. However, due to their poor solubility during digestion, carotenoid bioavailability is low and variable. In this study, we investigated the effect of frequently consumed proteins on carotenoid bioaccessibility and cellular uptake. Whey protein isolate (WPI), soy protein isolate (SPI), sodium caseinate (SC), gelatin (GEL), turkey and cod, equivalent to 0/10/25/50% of the recommended dietary allowance (RDA, approx. 60g/d), were co-digested gastro-intestinally with carotenoid-rich food matrices (tomato and carrot juice, spinach), and digesta further studied in Caco-2 cell models. Lipid digestion, surface tension and microscopic visualization were also carried out. Co-digested proteins positively influenced the micellization of carotenes (up to 3-fold, depending on type and concentration), especially in the presence of SPI (p < 0.001). An increased cellular uptake was observed for xanthophylls/carotenes (up to 12/33%, p < 0.001), which was stronger for matrices with an initially poor carotenoid micellization (i.e., tomato juice, p < 0.001), similar to what was encountered for bioaccessibility. Turkey and cod had a weaker impact. Significant interactions between carotenoids, lipids and proteins were observed during digestion. Co-digested proteins generally improved lipid digestion in all matrices (p < 0.001), especially for carrot juice, though slight decreases were observed for GEL. Protein impact on the surface tension was limited. In conclusion, proteins generally improved both carotenoid bioaccessibility and cellular uptake, depending on the matrices and carotenoid-type (i.e., carotene vs. xanthophylls), which may be relevant under specific circumstances, such as intake of carotenoid-rich food items low in lipids.

Cronobacter sakazakii ATCC 29544 Translocated Human Brain Microvascular Endothelial Cells via Endocytosis, Apoptosis Induction, and Disruption of Tight Junction

Cronobacter sakazakii (C. sakazakii) is an emerging opportunistic foodborne pathogen that can cause neonatal necrotizing enterocolitis, meningitis, sepsis in neonates and infants with a relatively high mortality rate. Bacterial transcytosis across the human brain microvascular endothelial cells (HBMEC) is vital for C. sakazakii to induce neonatal meningitis. However, few studies focus on the mechanisms by which C. sakazakii translocates HBMEC. In this study, the translocation processes of C. sakazakii on HBMEC were explored. C. sakazakii strains could effectively adhere to, invade and intracellularly survive in HBMEC. The strain ATCC 29544 exhibited the highest translocation efficiency across HBMEC monolayer among four tested strains. Bacteria-contained intracellular endosomes were detected in C. sakazakii-infected HBMEC by a transmission electron microscope. Endocytosis-related proteins CD44, Rab5, Rab7, and LAMP2 were increased after infection, while the level of Cathepsin L did not change. C. sakazakii induced TLR4/NF-κB inflammatory signal pathway activation in HBMEC, with increased NO production and elevated mRNA levels of IL-8, IL-6, TNF-α, IL-1β, iNOS, and COX-2. C. sakazakii infection also caused LDH release, caspase-3 activation, and HBMEC apoptosis. Meanwhile, increased Dextran-FITC permeability and decreased trans epithelial electric resistance indicated that C. sakazakii disrupted tight junction of HBMEC monolayers, which was confirmed by the decreased levels of tight junction-related proteins ZO-1 and Occludin. These findings suggest that C. sakazakii induced intracellular bacterial endocytosis, stimulated inflammation and apoptosis, disrupted monolayer tight junction in HBMEC, which all together contribute to bacterial translocation.

Development of an Advanced Multicellular Intestinal Model for Assessing Immunomodulatory Properties of Anti-Inflammatory Compounds

Intestinal inflammation is the collective term for immune system-mediated diseases of unknown, multifactorial etiology, with often complex interactions between genetic and environmental factors. To mechanistically investigate the effect of treatment with compounds possessing immunomodulating properties in the context of intestinal inflammation, we developed an immunocompetent in vitro triculture intestinal model consisting of a differentiated intestinal epithelial layer (Caco-2/HT29-MTX) and immunocompetent cells (differentiated THP-1). The triculture mimicked a healthy intestine with stable barrier integrity. Lipopolysaccharide treatment triggered a controlled and reversible inflammatory state, resulting in significant impairment of barrier integrity and release of pro-inflammatory cytokines and chemokines, which are known hallmarks of intestinal inflammation. Treatment with known anti-inflammatory reference compounds (TPCA-1 and budenoside) prevented the induction of an inflammatory state; the decreasing triculture responses to this treatment measured by cytokine release, transepithelial electric resistance (TEER), and epithelial layer permeability proved the suitability of the intestinal model for anti-inflammatory drug screening. Finally, selected tobacco alkaloids (nicotine and anatabine (R/S and S forms)) were tested in the in vitro triculture for their potential anti-inflammatory properties. Indeed, naturally occurring alkaloids, such as tobacco-derived alkaloids, have shown substantial anti-inflammatory effects in several in vitro and in vivo models of inflammation, gaining increasing interest. Similar to the anti-inflammatory reference compounds, one of the tobacco alkaloids under investigation partially prevented the decrease in the TEER and increase in permeability and reduced the release of pro-inflammatory cytokines and chemokines. Taken together, these data confirm that our in vitro model is suitable for screening potential anti-inflammatory compounds in the context of intestinal inflammation.

Protective Effects of Chrysin Against Oxidative Stress and Inflammation Induced by Lead Acetate in Rat Kidneys: a Biochemical and Histopathological Approach

In this study, the protective effects of chrysin (CR) on lead acetate (PbAc)-induced renal toxicity in Sprague-Dawley rats were investigated with biochemical, histopathological, and immunohistochemical methods. In the study, rats were given orally at 30 mg/kg/body weight (BW) PbAc after CR of 25 and 50 mg/kg/BW was administered to them orally (a total of 7 administrations for 7 days). The results showed that CR reduced urea and creatinine levels by alleviating PbAc-induced kidney damage. It was determined that CR decreases PbAc-induced lipid peroxidation due to its antioxidant properties and increases catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) activities, and glutathione (GSH) levels. It was also detected that CR protects DNA from the toxic effects of PbAc and reduces 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. Biochemical and immunohistochemical findings demonstrated that CR had anti-inflammatory and antiapoptotic effects and reduced nuclear factor kappa-B (NF-κB), interleukin-33 (IL-33), prostaglandin-E2 (PGE-2), tumor necrosis factor-α (TNF-α), p53 levels, and the activities of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), which were increased with PbAc administration. Moreover, CR was found to increase the levels of aquaporin-1 (AQP-1) and nephrine in PbAc-induced kidney tissue. CR decreased the contents of lead (Pb), zinc (Zn), iron (Fe), sodium (Na), and copper (Cu) and increased those of potassium (K) calcium (Ca) in renal tissue. These results indicated that CR considerably alleviates kidney toxicity caused by PbAc.

Common and Novel Markers for Measuring Inflammation and Oxidative Stress Ex Vivo in Research and Clinical Practice-Which to Use Regarding Disease Outcomes?

Many chronic conditions such as cancer, chronic obstructive pulmonary disease, type-2 diabetes, obesity, peripheral/coronary artery disease and auto-immune diseases are associated with low-grade inflammation. Closely related to inflammation is oxidative stress (OS), which can be either causal or secondary to inflammation. While a low level of OS is physiological, chronically increased OS is deleterious. Therefore, valid biomarkers of these signalling pathways may enable detection and following progression of OS/inflammation as well as to evaluate treatment efficacy. Such biomarkers should be stable and obtainable through non-invasive methods and their determination should be affordable and easy. The most frequently used inflammatory markers include acute-phase proteins, essentially CRP, serum amyloid A, fibrinogen and procalcitonin, and cytokines, predominantly TNFα, interleukins 1β, 6, 8, 10 and 12 and their receptors and IFNγ. Some cytokines appear to be disease-specific. Conversely, OS-being ubiquitous-and its biomarkers appear less disease or tissue-specific. These include lipid peroxidation products, e.g., F2-isoprostanes and malondialdehyde, DNA breakdown products (e.g., 8-OH-dG), protein adducts (e.g., carbonylated proteins), or antioxidant status. More novel markers include also -omics related ones, as well as non-invasive, questionnaire-based measures, such as the dietary inflammatory-index (DII), but their link to biological responses may be variable. Nevertheless, many of these markers have been clearly related to a number of diseases. However, their use in clinical practice is often limited, due to lacking analytical or clinical validation, or technical challenges. In this review, we strive to highlight frequently employed and useful markers of inflammation-related OS, including novel promising markers.

Crocin ameliorates arsenic trioxide‑induced cardiotoxicity via Keap1-Nrf2/HO-1 pathway: Reducing oxidative stress, inflammation, and apoptosis

Arsenic trioxide (ATO) is an excellent therapy for acute promyelocytic leukemia; however, its use is limited due to its cardiotoxicity. Crocin (CRO) possesses abundant pharmacological and biological properties, including antioxidant, anti-inflammatory, and anti-apoptotic. This study examined the cardioprotective effects of crocin and explored their mechanistic involvement in ATO-induced cardiotoxicity. Forty-eight male rats were treated with ATO to induce cardiotoxicity. In combination with ATO, CRO were given to evaluate its cardioprotection. The results demonstrated that CRO administration not only diminished QTc prolongation, myocardial enzymes and Troponin T levels but also improved histopathological results. CRO administration reduced reactive oxygen species generation. However, the CRO administration caused an increase in glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and total sulphydryl levels and a decrease in malondialdehyde content, gamma glutamyl transferase and lipid hydroperoxides levels and proinflammatory cytokines. Importantly, immunohistochemical analysis, real time PCR and western blotting showed a reduction in Caspase-3 and Bcl-2-associated X protein expressions and enhancement of B cell lymphoma-2 expression. Real time PCR and western blotting showed a reduction in proinflammatory cytokines. Moreover, CRO caused an activation in nuclear factor erythroid-2 related factor 2, leading to enhanced Kelch-like ECH-associated protein 1, heme oxygenase-1 and nicotinamide adenine dinucleotide quinone dehydrogenase 1 expressions involved in Nrf2 signaling during ATO-induced cardiotoxicity. CRO was shown to ameliorate ATO-induced cardiotoxicity. The mechanisms for CRO amelioration of cardiotoxicity due to inflammation, oxidative damage, and apoptosis may occur via an up-regulated Keap1-Nrf2/HO-1 signaling pathway.

Factors affecting the fate of β-carotene in the human gastrointestinal tract: A narrative review

Carotenoids and their metabolites play crucial roles in human health such as in immunity, cell differentiation, embryonic development, maintenance of plasma membrane integrity, and gastrointestinal functions, in addition to counteracting night blindness and other eye-related diseases. However, carotenoid bioavailability is highly variable and often low. The bioavailability of β-carotene, among the most frequently consumed carotenoid from the diet, is determined by food matrix related factors such as carotenoid dose, its location in food the matrix, the physical state in food, the presence of other food compounds in the matrix such as dietary fiber, dietary lipids, other micronutrients present such as minerals, and food processing, influencing also the size of food particles, and the presence of absorption inhibitors (fat replacers and anti-obesity drugs) or enhancers (nano-/micro-formulations). However, also host-related factors such as physiochemical interactions by gastrointestinal secretions (enzyme and salts) and other host-related factors such as surgery, age, disease, obesity, and genetic variations have shown to play a role. This review contributes to the knowledge regarding factors affecting the bioavailability of β-carotene (food and host-relegated), as well as highlights in vitro models employed to evaluate β-carotene bioavailability aspects.

Sulforaphane prevents chromium-induced lung injury in rats via activation of the Akt/GSK-3β/Fyn pathway

Chromium (Cr) is an internationally recognized carcinogenic hazard that causes serious pulmonary toxicity. However, Cr-induced pulmonary toxicity lacks effective treatment to date. Sulforaphane (SFN), a well-known organosulfur compound, has gained increasing attention because of its unique biological function. This study investigates if SFN could decrease K₂Cr₂O₇-induced pulmonary toxicity and a potential mechanism involved using a rat 35-day Cr-induced pulmonary toxicity model and the mouse alveolar type II epithelial cell line (MLE-12). The results showed that SFN prevented Cr-induced oxidative stress, histopathological lesions, inflammation, apoptosis, and changes in protein kinase B (Akt) and glycogen synthase kinase 3 beta (GSK-3β) levels in vivo and in vitro. However, SFN can not play the protective effect against K₂Cr₂O₇-induced cell injury after treating by an Akt-specific inhibitor (MK-2206 2HCl) in MLE-12 cells. Furthermore, SFN increased the expression of nuclear factor-E2-related factor-2 (Nrf2) phase II detoxification enzymes. Collectively, this study demonstrates that SFN prevents K₂Cr₂O₇-induced lung toxicity in rats through enhancing Nrf2-mediated exogenous antioxidant defenses via activation of the Akt/GSK-3β/Fyn signaling pathway. SFN may be a novel natural substance to cure Cr-induced lung toxicity.

Soluble silver ions from silver nanoparticles induce a polarised secretion of interleukin-8 in differentiated Caco-2 cells

Because of their antimicrobial properties, silver nanoparticles are increasingly incorporated in food-related and hygiene products, which thereby could lead to their ingestion. Although their cytotoxicity mediated by oxidative stress has been largely studied, their effects on inflammation remain controversial. Moreover, the involvement of silver ions (originating from Ag0 oxidation) in their mode of action is still unclear. In this context, the present study aims at assessing the impact of silver nanoparticles on the secretion of the pro-inflammatory chemokine interleukin-8 by Caco-2 cells forming an in vitro model of the intestinal mucosal barrier. Silver nanoparticles induced a vectorized secretion of interleukin-8 towards the apical compartment, which is found in the medium 21 h after the incubation. This secretion seems mediated by Nrf2 signalling pathway that orchestrates cellular defense against oxidative stress. The soluble silver fraction of silver nanoparticles suspensions led to a similar amount of secreted interleukin-8 than silver nanoparticles, suggesting an involvement of silver ions in this interleukin-8 secretion.

Modulation of Antibacterial, Antioxidant, and Anti-Inflammatory Properties by Drying of Prunus domestica L. Plum Juice Extracts

The consumption of plums in a fresh form is seasonal, therefore the transformation of plum juice extracts into powdered form is a good alternative for its longer availability throughout the year. The drying process can moderate the physical and chemical properties of the plum extracts, thus, this study examined the changes in biological activity, i.e., antibacterial, antioxidant, and anti-inflammatory properties moderated by freeze, vacuum, and spray drying. It was suggested that the drying processes and the applied parameters might moderate the content of polyphenolic compounds in the powders, which influence the different levels of growth inhibition against the foodborne pathogens (17% to 58% of inhibition), demonstrating a strain-dependent effect. These powders could also induce cellular protection against oxidative stress by preventing intracellular reactive oxygen species (ROS) accumulation (23% to 37% of reduction), but the level of antioxidant capacity may be determined by the conditions applied during the drying process. Moreover, plum extract powders exhibited a greater anti-inflammatory capacity (24% to 39% of inhibition), which would be influenced both, by the type of treatment used and by the temperature used in each treatment. The results demonstrate that the selection of the drying method can be an effective tool for modulating the composition, physical, and bioactive properties of plum extracts powders.

Catechin and Procyanidin B2 Modulate the Expression of Tight Junction Proteins but Do Not Protect from Inflammation-Induced Changes in Permeability in Human Intestinal Cell Monolayers

The possibility of counteracting inflammation-related barrier defects with dietary compounds such as (poly)phenols has raised much interest, but information is still scarce. We have investigated here if (+)-catechin (CAT) and procyanidin B₂ (PB₂), two main dietary polyphenols, protect the barrier function of intestinal cells undergoing inflammatory stress. The cell model adopted consisted of co-cultured Caco-2 and HT29-MTX cells, while inflammatory conditions were mimicked through the incubation of epithelial cells with the conditioned medium of activated macrophages (MCM). The epithelial barrier function was monitored through trans-epithelial electrical resistance (TEER), and ROS production was assessed with dichlorofluorescein, while the expression of tight-junctional proteins and signal transduction pathways were evaluated with Western blot. The results indicated that MCM produced significant oxidative stress, the activation of NF-κB and MAPK pathways, a decrease in occludin and ZO-1 expression, and an increase in claudin-7 (CL-7) expression, while TEER was markedly lowered. Neither CAT nor PB₂ prevented oxidative stress, transduction pathways activation, ZO-1 suppression, or TEER decrease. However, PB₂ prevented the decrease in occludin expression and both polyphenols produced a huge increase in CL-7 abundance. It is concluded that, under the conditions adopted, CAT and PB₂ do not prevent inflammation-dependent impairment of the epithelial barrier function of intestinal cell monolayers. However, the two compounds modify the expression of tight-junctional proteins and, in particular, markedly increase the expression of CL-7. These insights add to a better understanding of the potential biological activity of these major dietary flavan-3-ols at intestinal level.

Lactobacillus bulgaricus or Lactobacillus rhamnosus Suppresses NF-κB Signaling Pathway and Protects against AFB₁-Induced Hepatitis: A Novel Potential Preventive Strategy for Aflatoxicosis?

Aflatoxin B₁ (AFB₁), a mycotoxin found in food and feed, is immunotoxic to animals and poses significant threat to the food industry and animal production. The primary target of AFB₁ is the liver. To overcome aflatoxin toxicity, probiotic-mediated detoxification has been proposed. In the present study, to investigate the protective effects and molecular mechanisms of Lactobacillus bulgaricus or Lactobacillus rhamnosus against liver inflammatory responses to AFB₁, mice were administered with AFB₁ (300 μg/kg) and/or Lactobacillus intragastrically for 8 weeks. AML12 cells were cultured and treated with AFB₁, BAY 11-7082 (an NF-κB inhibitor), and different concentrations of L. bulgaricus or L. rhamnosus. The body weight, liver index, histopathological changes, biochemical indices, cytokines, cytotoxicity, and activation of the NF-κB signaling pathway were measured. AFB₁ exposure caused changes in liver histopathology and biochemical functions, altered inflammatory response, and activated the NF-κB pathway. Supplementation of L. bulgaricus or L. rhamnosus significantly prevented AFB₁-induced liver injury and alleviated histopathological changes and inflammatory response by decreasing NF-κB p65 expression. The results of in vitro experiments revealed that L.rhamnosus evidently protected against AFB₁-induced inflammatory response and decreased NF-κB p65 expression when compared with L. bulgaricus. These findings indicated that AFB₁ exposure can cause inflammatory response by inducing hepatic injury, and supplementation of L. bulgaricus or L. rhamnosus can produce significant protective effect against AFB₁-induced liver damage and inflammatory response by regulating the activation of the NF-κB signaling pathway.

Buckwheat and buckwheat enriched products exert an anti-inflammatory effect on the myofibroblasts of colon CCD-18Co

Buckwheat (BW) constitutes a good source of bioactive components that show anti-inflammatory effects in vitro and in vivo. The use of functional foods in the prevention and treatment of inflammatory bowel diseases (IBDs) has aroused increasing interest. This study investigates the effect of in vitro digested BW and BW-enriched products (BW-enriched wheat breads, roasted BW groats -fermented and non-fermented-, and BW sprouts) on colon myofibroblasts, the cells involved in the regulation of inflammatory response in the intestine. The cells were treated with different digested-BW products, alone or together with TNF-α (20 ng mL-1), and the effects on the cell migration, mitochondrial membrane potential and cell cycle, processes altered during intestinal inflammation, were investigated. A significant reduction in TNF-α-induced migration (25.5%, p < 0.05) and attenuation of the TNF-α-altered cell cycle (p < 0.05) was observed in myofibroblasts treated with BW-enriched white wheat bread. These results contribute to extend the beneficial effects derived from BW bioactive compounds, and suggest that BW consumption can exert beneficial effects on IBDs.

Characterisation of a canine epithelial cell line for modelling the intestinal barrier

Little is known about how food interacts with the intestinal epithelium during the digestion process. However, it is known that ingredients in food can modulate the intestinal barrier, and have the potential to disrupt homeostasis of the gut. Here, we characterise a conditionally immortalised canine intestinal epithelial cell (cIEC) line for use in in vitro assays, to assess the effect of food ingredients on intestinal barrier function, permeability, cell health, and inflammation. Microscopy and flow cytometry confirmed that cIECs had a phenotype consistent with those of epithelial origin, and were able to differentiate to mature enterocytes. The cIECs also formed a monolayer when grown on Transwell® inserts, producing functional tight junctions between the cells. In contrast to the human-derived Caco-2 cell line, transepithelial electrical resistance (TEER) was increased in cIECs in response to two different raw ingredients. The exposure of cIECs to known inflammatory stimuli and raw ingredients induced the nuclear translocation of nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-?B). This work demonstrates the value of a unique cIEC in vitro model to study the effects of food ingredients on canine intestinal function and health, and supports continued efforts to reduce and refine the use of animals in scientific research.

Excess of nutrient-induced morphofunctional adaptation and inflammation degree in a Caco2/HT-29 in vitro intestinal co-culture

OBJECTIVES

The intestinal cell function can be modulated by the type and quantity of nutrients. The aim of this study was to evaluate the effects of an excess of nutrients on intestinal morphofunctional features and a possible association of inflammation in a 70/30 Caco2/HT-29 intestinal in vitro co-culture.

METHODS

An excess of nutrients (EX) was obtained by progressively increasing the medium change frequency with respect to standard cell growth conditions (ST) from confluence (T0) to 15 d after confluence (T15).

RESULTS

In comparison with the ST group, the EX group revealed a maintenance in the number of microvilli, an increase in follicle like-structures and mucus production, and a decrease in the number of tight junction. The specific activity of markers of intestinal differentiation, alkaline phosphatase and aminopeptidase N, and of the enterocyte differentiation specific marker, dipeptidyl peptidase-IV, were progressively raised. The transepithelial electrical resistance, indicative of the co-culture barrier properties, decreased, whereas Lucifer yellow P_app evaluation, an index of the paracellular permeability to large molecules, showed an increase. Reactive oxygen species and nitric oxide production, indicative of an oxidative status, together with interleukin-6, interleukin-8, indicative of a low-grade inflammation, and peptide YY secretion were higher in the EX group than in the ST group. The differences between ST and EX were particularly evident at T15.

CONCLUSION

These data support the suitability of our in vitro gut model for obesity studies at the molecular level and the necessity to standardize the medium frequency change in intestinal culture.

Proteomic response of inflammatory stimulated intestinal epithelial cells to in vitro digested plums and cabbages rich in carotenoids and polyphenols

Due to their anti-oxidant and anti-inflammatory potential, polyphenol and carotenoid-rich plant foods have been suggested as promising phytochemicals in the prevention of or as adjuvants regarding inflammatory bowel diseases (IBD). In the present study, we investigated whether plum (Italian Plum, Prunus cocomilla), or cabbage (Kale, Brassica oleracea var. sabellica), selected for their high phytochemical content, are able to reduce inflammation in cellular models of the intestinal epithelium, employing proteomic methods. For this purpose, plum/cabbage (carotenoid content: 1.9 mg per 100 g resp. 13 mg per 100 g; polyphenol content: 83 mg per 100 g resp. 27 mg per 100 g) were gastro-intestinally digested, and aliquots exposed (18 h) to either a monoculture (Caco-2) or a triple culture (Caco-2/HT-29-MTX (90 : 10, v/v) with THP-1 like macrophages), stimulated (with LPS, TNF-α, and IL-1β) to induce inflammation. Cells (Caco-2, Caco-2/HT-29-MTX, and THP-1) were then harvested separately, and proteomic analyses of total cell extracts were carried out by 2D-DIGE. In the monoculture, 68 protein-spots were significantly (p < 0.05, expression ratio >1.5) differentially regulated due to the Kale and Italian plum digesta, and in the co-culture 206 protein-spots, compared to digesta without plum/cabbage. These belonged to 27 (monoculture) and 76 (coculture) uniquely identified proteins, suggesting the coculture to be a more sensitive model. Proteins included antioxidant enzymes such as catalase, superoxide dismutase and glutathione-S-transferases. Only 3 proteins were differentially regulated in the THP-1 cells, perhaps as these were only indirectly exposed. The results show promise regarding some aspects related to IBD complications, however, employing phytochemical-rich food items should be further investigated in in vivo trials.

Matrine alleviates lipopolysaccharide-induced intestinal inflammation and oxidative stress via CCR7 signal

The aim of this study was to investigate the protective effects of matrine on lipopolysaccharide (LPS)-induced inflammation and oxidative stress in vivo and in vitro. The results showed that matrine improved intestinal inflammatory status and oxidative balance and enhanced chemokine receptor 7 (CCR7) expression. In LPS-challenged mice and Caco-2 cells, matrine alleviated LPS-induced inflammation and oxidative stress via downregulating pro-inflammatory cytokines (IL-1β and IL-17) and malondialdehyde (MDA) production. CCR7-siRNA transfection blocked the protective effects of matrine on LPS-induced inflammation and oxidative stress and exacerbated LPS caused injury. In conclusion, matrine alleviates LPS-induced intestinal inflammation and oxidative stress in mice and Caco-2 cells, which may be associated with CCR7 signal.

GSPE reduces lead-induced oxidative stress by activating the Nrf2 pathway and suppressing miR153 and GSK-3β in rat kidney

Lead (Pb) is a global environmental health hazard that leads to nephrotoxicity. However, the effective treatment of Pb-induced nephrotoxicity remains elusive. Grape seed procyanidin extract (GSPE) has beneficial properties for multiple biological functions. Therefore, the present study investigated whether GSPE reduced Pb-induced nephrotoxicity as well as the protective mechanism of GSPE in a well-established 35-day Pb induced nephrotoxicity rat model. The results showed that GSPE normalized Pb-induced oxidative stress, histological damage, inflammatory, apoptosis, and changes of miR153 and glycogen synthase kinase 3β (GSK-3β) levels in rat kidney. Moreover, GSPE enhanced the induction of phase II detoxifying enzymes (heme oxygenase-1 and NAD(P)H quinone oxidoreductase 1) by increasing nuclear factor-erythroid-2-related factor 2 (Nrf2) expression. This study identifies for the first time that Pb-induced oxidative stress in rat kidney is attenuated by GSPE treatment via activating Nrf2 signaling pathway and suppressing miR153 and GSK-3β. Nrf2 signaling provides a new therapeutic target for renal injury induced by Pb, and GSPE could be a potential natural agent to protect against Pb-induced nephrotoxicity.

Metabolic Effects of Inflammation on Vitamin A and Carotenoids in Humans and Animal Models

The association between inflammation and vitamin A (VA) metabolism and status assessment has been documented in multiple studies with animals and humans. The relation between inflammation and carotenoid status is less clear. Nonetheless, it is well known that carotenoids are associated with certain health benefits. Understanding these relations is key to improving health outcomes and mortality risk in infants and young children. Hyporetinolemia, i.e., low serum retinol concentrations, occurs during inflammation, and this can lead to the misdiagnosis of VA deficiency. On the other hand, inflammation causes impaired VA absorption and urinary losses that can precipitate VA deficiency in at-risk groups of children. Many epidemiologic studies have suggested that high dietary carotenoid intake and elevated plasma concentrations are correlated with a decreased risk of several chronic diseases; however, large-scale carotenoid supplementation trials have been unable to confirm the health benefits and in some cases resulted in controversial results. However, it has been documented that dietary carotenoids and retinoids play important roles in innate and acquired immunity and in the body's response to inflammation. Although animal models have been useful in investigating retinoid effects on developmental immunity, it is more challenging to tease out the effects of carotenoids because of differences in the absorption, kinetics, and metabolism between humans and animal models. The current understanding of the relations between inflammation and retinoid and carotenoid metabolism and status are the topics of this review.

A Gastrointestinally Digested Ribes nigrum L. Fruit Extract Inhibits Inflammatory Response in a Co-culture Model of Intestinal Caco-2 Cells and RAW264.7 Macrophages

Blackcurrant fruits are a rich source of polyphenolic compounds with high antioxidant capacity and potent anti-inflammatory properties. In this study, blackcurrant extract digested in an artificial gastrointestinal tract and its intestinal permeable fraction were investigated for their ability to suppress inflammatory responses induced in a two-component cell culture system of intestinal epithelial cells and macrophages. The obtained results showed the capacity of the extract at a concentration of 1 mg of freeze-dried blackcurrant powder per mL to down-regulate the expression of inflammatory mediators, such as IL-8 (54 ± 7%) and COX-2 (17 ± 6%) in intestinal cells and IL-1α (76 ± 4%), IL-1β (91 ± 2%), and IL-6 (61 ± 5%) in macrophages stimulated with lipopolysaccharides. Inhibited COX-2 (44 ± 6%) and iNOS (15 ± 7%) expression played a role in reducing the production of prostaglandin E₂ (40 ± 20%) and NO (31 ± 9%), respectively. Decreased TNF-α secretion (24 ± 5%) by activated macrophages was also observed after treatment with blackcurrant extract. Moreover, the gastrointestinal-digested extract (0.01-1 mg/mL) dose dependently decreased the enhanced ROS generation (14-54%) and oxidative DNA damage (16-37%) induced in intestinal cells. The increased intestinal permeability caused by proinflammatory mediators, as assessed by transepithelial electrical resistance, was completely counteracted.

Bioactivity of Polyphenols: Preventive and Adjuvant Strategies toward Reducing Inflammatory Bowel Diseases-Promises, Perspectives, and Pitfalls

Inflammatory bowel diseases (IBDs) are characterized by autoimmune and inflammation-related complications of the large intestine (ulcerative colitis) and additional parts of the digestive tract (Crohn's disease). Complications include pain, diarrhoea, chronic inflammation, and cancer. IBD prevalence has increased during the past decades, especially in Westernized countries, being as high as 1%. As prognosis is poor and medication often ineffective or causing side effects, additional preventive/adjuvant strategies are sought. A possible approach is via diets rich in protective constituents. Polyphenols, the most abundant phytochemicals, have been associated with anti-inflammatory, antioxidant, immunomodulatory, and apoptotic properties. Locally reducing oxidative stress, they can further act on cellular targets, altering gene expression related to inflammation, including NF-κB, Nrf-2, Jak/STAT, and MAPKs, suppressing downstream cytokine formation (e.g., IL-8, IL-1β, and TNF-α), and boosting the bodies' own antioxidant status (HO-1, SOD, and GPx). Moreover, they may promote, as prebiotics, healthy microbiota (e.g., Bifidobacteria, Akkermansia), short-chain fatty acid formation, and reduced gut permeability/improved tight junction stability. However, potential adverse effects such as acting as prooxidants, or perturbations of efflux transporters and phase I/II metabolizing enzymes, with increased uptake of undesired xenobiotics, should also be considered. In this review, we summarize current knowledge around preventive and arbitrary actions of polyphenols targeting IBD.