Intestinal inflammation and the diet: Is food friend or foe?

Anti-Aging Physiological Roles of Aryl Hydrocarbon Receptor and Its Dietary Regulators

The vast majority of the literature on the aryl hydrocarbon receptor is concerned with its functions in xenobiotic detoxification. However, in the course of evolution, this receptor had to have physiological (rather than toxicological) functions. Our aim was to review the aryl hydrocarbon receptor’s role in the physiological functions involved in aging. This study was performed by searching the MEDLINE and Google Academic databases. A total of 34 articles were selected that focused specifically on the aryl hydrocarbon receptor and aging, the aryl hydrocarbon receptor and physiological functions, and the combination of both. This receptor’s main physiological functions (mediated by the modulation of gene expression) were cell regeneration, the immune reaction, intestinal homeostasis, and cell proliferation. Furthermore, it was shown that the loss of this receptor led to premature aging. This process may be caused by the dysregulation of hematopoietic stem cells, loss of glucose and lipid homeostasis, increase in inflammation, and deterioration of the brain. We conclude that the aryl hydrocarbon receptor, apart from its well-established role in xenobiotic detoxication, plays an important role in physiological functions and in the aging process. Modulation of the signaling pathway of this receptor could be a therapeutic target of interest in aging.

3,3'-Diindolylmethane Improves Intestinal Permeability Dysfunction in Cultured Human Intestinal Cells and the Model Animal Caenorhabditis elegans

3,3'-Diindolylmethane (DIM), a digestive metabolite originating from cruciferous vegetables, has dietary potential for the treatment of various human intestinal diseases. Although intestinal permeability dysfunction is closely related to the initiation and progression of human intestinal inflammatory diseases (IBDs), the effect of DIM on intestinal permeability is unclear. We evaluated the effect of DIM on the intestinal permeability of human intestinal cell monolayers and the animal model Caenorhabditis elegans, which were treated with IL-1β and Pseudomonas aeruginosa, respectively, to mimic IBD conditions. DIM substantially restored the intestinal permeability of differentiated Caco-2 cells by enhancing the expression of tight junction proteins (including occludin and ZO-1). Compared to the IL-1β single treatment (551.0 ± 49.0 Ω·cm²), DIM (10 μM) significantly increased the transepithelial electrical resistance (TEER) of Caco-2 cell monolayers (919.0 ± 66.4 Ω·cm², p < 0.001). DIM also ameliorated the impaired intestinal permeability and extended the lifespan of C. elegans fed P. aeruginosa. The mean lifespan of DIM-treated worms (10.8 ± 1.3 days) was higher than that of control-treated worms (9.7 ± 1.1 days, p < 0.01). Thus, DIM is a potential nutraceutical candidate for the treatment of leaky gut syndrome by improving intestinal permeability.

Treatment with a Zinc Metalloprotease Purified from Bothrops moojeni Snake Venom (BmooMP-Alpha-I) Reduces the Inflammation in an Experimental Model of Dextran Sulfate Sodium-Induced Colitis

It has been described that the metalloprotease BmooMP-alpha-I purified from Bothrops moojeni snake venom is able to hydrolyze the TNF molecule. However, this observation has been based mainly on in vitro investigation, in addition to molecular modeling and docking approaches. Considering that there is no in vivo study to demonstrate the biological effects of this enzyme, the major aim to the present work was to investigate whether the BmooMP-alpha-I has any anti-inflammatory efficacy by setting up a murine experimental design of colitis induced by dextran sulfate sodium (DSS). For this purpose, C57BL/6 mice were divided into six groups, as follows: (i) animals without intestinal inflammation, (ii) animals without intestinal inflammation treated with BmooMP-alpha-I (50 μg/animal/day), and (iii) animals with intestinal inflammation induced by 3% of DSS, (iv) mice with intestinal inflammation induced by DSS and treated with BmooMP-alpha-I enzyme at the 50, 25, or 12.5 μg/animal/day dosages by intraperitoneal route. Clinical signs of colitis were observed daily for calculating the morbidity scores, cytokine measurements, and histological features. We observed that the animals treated with different doses of the enzyme presented a remarkable improvement of colitis signs, as confirmed by a significant increase of the intestine length in comparison to the DSS group. Also, no difference was observed between the groups treated with the enzyme or vehicle, as the colon length of these animals was slightly lower than that of the group of healthy animals, without induction of intestinal inflammation. The cytokine quantification in supernatants of intestinal tissue homogenates showed a significant reduction of 38% in IFN-gamma levels, when the animals were treated with 50 μg of the BmooMP-alpha-I compared to the animals receiving DSS only. A significant reduction of 39% in TNF levels was also observed in all doses of treatment with BmooMP-alpha-I, in addition to a significant reduction of 35% in the amount of IL-12p40. Histological examinations revealed that the BmooMP-alpha-I 50 μg treated group preserved colon architecture and goblet cells and reduced the ulcer area, when compared with DSS mice, which showed typical inflammatory changes in tissue architecture, such as ulceration, crypt dilation, loss of tissue architecture, and goblet cell depletion, accompanied by a significant cell infiltration. In conclusion, our results suggest that the improvement of clinical scores and histological findings related to BmooMP-alpha-I treatment in this experimental model could be attributed to the metalloprotease ability to modulate cytokine production locally at the inflamed intestine. These findings highlight the potential anti-inflammatory role and effectiveness of this enzyme as a therapeutic alternative in this type of immunopathological condition.

5-aminosalicylic acid improves lipid profile in mice fed a high-fat cholesterol diet through its dual effects on intestinal PPARγ and PPARα

Obesity is associated with a series of metabolic complications, including dyslipidemia and insulin resistance (IR) that lack effective therapies. In recent years, intestinal inflammation has been suggested to contribute to obesity related metabolic syndrome and targeting gut inflammation with 5-ASA improves diet induced IR, however, its role in dyslipidemia is unknown and has never been explored. In the present study, we reported for the first time that administration of 5-ASA for 12 weeks significantly improved lipid profile by repressing plasma triglycerides and free cholesterol levels in mice fed high-fat cholesterol diet (HFC). In addition, liver lipids were significantly reduced by 5-ASA treatment in HFC-fed mice. Mechanistically, anti-inflammatory genes peroxisome proliferator-activated receptor-γ (Pparγ) and M2 marker, such as Mrc1 and Ym1, were remarkably upregulated, while pro-inflammation gene monocyte chemoattractant protein-1 (Mcp-1) were downregulated in small intestine of mice treated by 5-ASA. Further, 5-ASA improved gastrointestinal barrier by increasing the expression of the tight junction marker ZO-1. 5-ASA also enhanced cholesterol translocation by elevating genes expression of Npc1l1 and Abcg5/8. Moreover, mice fed HFC 5-ASA expressed increased Pparα in small intestinal and its target genes function in lipid oxidation and hydrolysis were remarkable elevated. Taken together, we reported a novel role of 5-ASA which may serve as a therapy target intestinal inflammation induced dyslipidemia.

Protective Effect of Glyceollins in a Mouse Model of Dextran Sulfate Sodium-Induced Colitis

Glyceollins, which are derived from daidzein in soybean in response to various stimuli or stresses, have been reported to activate antioxidant/detoxifying enzymes in a nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-dependent manner, in addition to exerting anti-inflammatory effects in murine macrophages. As the Nrf2 signaling pathway is known to antagonize nuclear factor (NF)-κB signaling, glyceollins likely have the potential to prevent or treat inflammatory bowel disease. Thus, this study was conducted to examine whether glyceollins could inhibit dextran sulfate sodium (DSS)-induced colitis in a mouse model. Ulcerative colitis (UC) was induced in male BALB/c mice by administering drinking water with 4% DSS for 5 days. Glyceollins (4 or 10 mg/kg of body weight) were orally administered 48 h before and after DSS treatment. We found that glyceollins alleviated histological colon damage and inflammation induced by DSS treatment. More specifically, glyceollins reduced plasma levels of inflammatory cytokines, such as tumor necrosis factor-α and interleukin-6, which were otherwise markedly increased by DSS treatment. Markers of tissue damage, including malondialdehyde and 8-hydroxy-2-guanosine, were significantly increased by DSS treatment; however, this effect was mitigated through concomitant treatment with glyceollins. Furthermore, nuclear accumulation of NF-κB p65 and the expression of inducible nitric oxide synthase were upregulated by glyceollins, consistent with the observed modulation of inflammatory markers. In conclusion, glyceollins have therapeutic potential for UC and merit further clinical study.

Relationship between gastrointestinal micro-ecological imbalance and development of gastric cancer

The human body and microorganisms present in the body form a symbiotic system as the relationship between eukaryotes and prokaryotes. Therefore, it is not enough to study human diseases only in terms of human body. Recent studies have pointed out that microorganisms are involved in the occurrence of a large number of malignant tumors. According to a conservative estimate, at least 15% of cancer cases are associated with infectious agents. Gastric cancer is the second major cause of global cancer deaths. For a long period of time, researchers believe that Helicobacter pylori associated with chronic gastritis is the strongest risk factor for the occurrence of gastric cancer. However, with the progress of molecular biology research, it has been found that there is a close interaction between the large microbial flora and Helicobacter pylori in the gastrointestinal tract. The changes of microbial community composition have important effects on the formation, development and intervention of gastric cancer. This article will review the occurrence and development of gastrointestinal microorganism and gastric cancer.