Dietary selenium deficiency exacerbates DSS-induced epithelial injury and AOM/DSS-induced tumorigenesis

Selenium alleviates dextran sulfate sodium-induced colitis and inhibits ferroptosis of intestinal epithelial cells via upregulating glutathione peroxidase 4

BACKGROUND AND AIM

Selenium, an essential micronutrient for humans, has been shown to be protective against ulcerative colitis (UC), but the exact mechanism remains unclear. The role of selenium, protecting against ferroptosis of intestinal epithelial cells (IECs) in colitis, was investigated in this current study.

METHODS

Serum selenium level and ferroptosis-related gene expression in the colonic mucosa were measured in UC patients and healthy controls. The effects of sodium selenite supplementation on experimental colitis were investigated in dextran sulfate sodium (DSS)-treated mice. The influence of sodium selenite on IEC ferroptosis was evaluated through assessing cell death rate, intracellular ferrous iron content, lipid reactive oxygen species level, and mitochondrial membrane damage of DSS-treated Caco-2 cells. Moreover, glutathione peroxidase 4 (GPX4) and acyl-CoA synthetase long-chain family member 4, ferroptosis-related genes, were detected in Caco-2 cells and mouse intestines.

RESULTS

Serum selenium was decreased in UC patients in comparison with healthy individuals. Additionally, serum selenium level was negatively correlated with disease activity and was associated with clinical inflammation and nutrition indicators. The expression of GPX4 in the mucosa of UC was positively correlated with serum selenium level. The in vivo experiments showed that selenium treatment ameliorated DSS-induced colitis and inhibited ferroptosis in IECs. The in vitro results suggested that selenium supplementation inhibited DSS-induced ferroptosis in Caco-2 cells. GPX4 was upregulated after selenium supplementation both in vivo and in vitro.

CONCLUSIONS

Serum selenium level was associated with IEC ferroptosis in UC patients. Selenium supplementation alleviates DSS-induced colitis and inhibits ferroptosis in IECs by upregulating the expression of GPX4.

Selenium deficiency in inflammatory bowel disease: A comprehensive meta-analysis

Background

Micronutrient deficiencies, particularly selenium, are common in Inflammatory Bowel Diseases and may influence disease progression and severity. Various studies have investigated blood selenium levels in patients with inflammatory bowel disease, but these studies have shown considerable heterogeneity and are generally limited by small sample sizes. Therefore, this study aims to clarify the selenium status in patients with inflammatory bowel disease compared to controls and to explore the potential of selenium supplementation as a therapeutic option.

Method

A comprehensive search of online databases from January 1980 to December 2023 was conducted, focusing on studies related to selenium levels in patients with inflammatory bowel disease. The relationship between blood selenium concentrations in inflammatory bowel disease patients and controls was pooled using a random-effects model.

Results

From the 1853 references screened, 20 studies were selected based on the inclusion criteria, involving 1792 inflammatory bowel disease patients (including both Crohn's disease and ulcerative colitis cases) and 1648 controls. The meta-analysis demonstrated that inflammatory bowel disease patients have significantly lower selenium levels compared to the control group. This trend was consistent across subgroups differentiated by study characteristics such as design, geographical location, selenium detection methods, types of samples analyzed, and age categories of participants, with particularly notable deficiencies observed in patients with Crohn's disease. The robustness of these findings was supported by sensitivity analysis, and tests for publication bias indicated no significant skewing of results.

Conclusion

The analysis confirms that inflammatory bowel disease patients, especially those with Crohn's disease, have significantly lower levels of selenium compared to controls, suggesting that that selenium supplementation may serve as a valuable adjunct to the therapeutic regimen for managing inflammatory bowel disease, particularly in patients identified with selenium insufficiency.

Effects of selenium biofortification on Pleurotus eryngii protein structure and digestive properties and its mitigation of lead toxicity: An in vitro and in vivo study

The development of safe and efficient dietary selenium sources to promote lead excretion is of great importance for public health. In this research, proteins from original Pleurotus eryngii (PEP) and Se-enriched P. eryngii (SePEP, Se content: 360.64 ± 3.11 mg/kg) were extracted and purified respectively for the further comparison of structural and digestive characteristics. Caco-2 monolayer membrane, in vitro simulated fermentation and acute lead exposure mice model were constructed to evaluate the effects of PEP and SePEP on lead excretion. The results indicated that Se biofortification significantly altered the amino acid composition and reduced the total sulfhydryl content of proteins (p < 0.05). SePEP could better alleviate lead-induced intestinal barrier damage and inhibit the absorption and accumulation of lead in both cell and mice models. Furthermore, SePEP promoted fecal adsorption and excretion of lead via regulating gut microbiota composition. SePEP can be considered a potentially functional Se source to promote lead excretion.

Selenium, Immunity, and Inflammatory Bowel Disease

Dietary intervention is a subject of growing interest in the management of inflammatory bowel disease (IBD), as new incident cases across the globe are rapidly rising, suggesting environmental factors as contributing elements. Dietary components and micronutrients have been associated with IBD pathogenesis or reductions in disease severity. Selenium, a diet-derived essential micronutrient that is important for proper immune system function, has received limited attention in the context of IBD. Selenium deficiency is a common finding in patients with IBD, but few clinical trials have been published to address the consequences of this deficiency. Here, we review the physiological and immunological roles of selenium and its putative role in IBD, and draw attention to knowledge gaps and unresolved issues, with the goal of stimulating more research on selenium in IBD.

Mannose coated selenium nanoparticles normalize intestinal homeostasis in mice and mitigate colitis by inhibiting NF-κB activation and enhancing glutathione peroxidase expression

Impaired intestinal homeostasis is a major pathological feature of inflammatory bowel diseases (IBD). Mannose and selenium (Se) both demonstrate potential anti-inflammatory and anti-oxidative properties. However, most lectin receptors bind free monosaccharide ligands with relatively low affinity and most Se species induce side effects beyond a very narrow range of dosage. This has contributed to a poorly explored therapies for IBD that combine mannose and Se to target intestinal epithelial cells (IECs) for normalization gut homeostasis. Herein, a facile and safe strategy for ulcerative colitis (UC) treatment was developed using optimized, mannose-functionalized Se nanoparticles (M-SeNPs) encapsulated within a colon-targeted hydrogel delivery system containing alginate (SA) and chitosan (CS). This biocompatible nanosystem was efficiently taken up by IECs and led to increased expression of Se-dependent glutathione peroxidases (GPXs), thereby modulating IECs' immune response. Using a mouse model of DSS-induced colitis, (CS/SA)-embedding M-SeNPs (C/S-MSe) were found to mitigate oxidative stress and inflammation through the inhibition of the NF-kB pathway in the colon. This stabilized mucosal homeostasis of IECs and ameliorated colitis-related symptoms, thereby providing a potential new approach for treatment of IBD.

Selenium in Surgery

Selenium, a micronutrient essential for many enzymatic functions, is crucial for maintaining human health. Its presence in the human diet is of paramount importance for metabolism and support of the immune system. Many diseases of surgical importance are related to the level of selenoproteins and their influence on different organs. The aim of this concise narrative review is to highlight the role of selenium as a trace element in various surgical morbidities, a concept that is often neglected or not well perceived by most surgeons.

Selenoprotein S maintains intestinal homeostasis in ulcerative colitis by inhibiting necroptosis of colonic epithelial cells through modulation of macrophage polarization

Rationale: Macrophage polarization plays an important role in the inflammatory regulation of ulcerative colitis (UC). In this context, necroptosis is a type of cell death that regulates intestinal inflammation, and selenoprotein S (SelS) is a selenoprotein expressed in intestinal epithelial cells and macrophages that prevents intestinal inflammation. However, the underlying mechanisms of SelS in both cell types in regulating UC inflammatory responses remain unclear. Therefore, the direct effect of SelS deficiency on necroptosis in colonic epithelial cells (CECs) was investigated. In addition, whether SelS knockdown exacerbated intestinal inflammation by modulating macrophage polarization to promote necroptosis in CECs was assessed. Methods: The UC model of SelS knockdown mice was established with 3.5% sodium dextran sulfate, and clinical indicators and colon injury were evaluated in the mice. Moreover, SelS knockdown macrophages and CECs cultured alone/cocultured were treated with IL-1β. The M1/M2 polarization, NF-κB/NLRP3 signaling pathway, oxidative stress, necroptosis, inflammatory cytokine, and tight junction indicators were analyzed. In addition, co-immunoprecipitation, liquid chromatography-mass spectrometry, laser confocal analysis, and molecular docking were performed to identify the interacting proteins of SelS. The GEO database was used to assess the correlation of SelS and its target proteins with macrophage polarization. The intervention effect of four selenium supplements on UC was also explored. Results: Ubiquitin A-52 residue ribosomal protein fusion product 1 (Uba52) was identified as a potential interacting protein of SelS and SelS, Uba52, and yes-associated protein (YAP) was associated with macrophage polarization in the colon tissue of patients with UC. SelS deficiency in CECs directly induced reactive oxygen species (ROS) production, necroptosis, cytokine release, and tight junction disruption. SelS deficiency in macrophages inhibited YAP ubiquitination degradation by targeting Uba52, promoted M1 polarization, and activated the NF-κB/NLRP3 signaling pathway, thereby exacerbating ROS-triggered cascade damage in CECs. Finally, exogenous selenium supplementation could effectively alleviate colon injury in UC. Conclusion: SelS is required for maintaining intestinal homeostasis and that its deletion enhances necroptosis in CECs, which is further exacerbated by promoting M1 macrophage polarization, and triggers more severe barrier dysfunction and inflammatory responses in UC.

Association of Blood Trace Elements Levels with Cardiovascular Disease in US Adults: a Cross-Sectional Study from the National Health and Nutrition Examination Survey 2011-2016

We aimed to explore the overall association between trace elements and cardiovascular disease (CVD) and its types in humans. A total of 5101 participants' blood samples from the 2011-2016 National Health and Nutrition Examination Survey were included. Biochemical data were collected from laboratory tests conducted at mobile screening centers. After assessing linearity, weighted logistic regression estimated the association between trace elements and various CVD types. Weighted quantile sum (WQS) regression and quantile-based g-computation (Qgcomp) evaluated the overall relationship between biological trace elements and CVD types. After fully adjusting for confounding factors, the odds ratios of overall CVD morbidity corresponding to the second, third, and fourth quartiles of higher selenium (Se) concentration were 0.711 (95% CI, 0.529-0.956, p = 0.024), 0.734 (95% CI, 0.546-0.987, p = 0.041), and 0.738 (95% CI, 0.554-0.983, p = 0.038), respectively. Moreover, an increase in the concentration of copper (Cu) was associated with an increased risk of stroke (95% CI, 1.012-1.094, p = 0.01), heart failure (95% CI, 1.001-1.095, p = 0.046), and heart attack (95% CI, 1.001-1.083, p = 0.046). As the concentration of trace elements in the body increased, there was a significant positive association between Cu and CVD prevalence. On the other hand, Se and zinc were negatively associated with CVD prevalence. A nonlinear relationship between Se and CVD was found, and an appropriate Se intake may reduce the risk of CVD. Cu levels positively correlated with CVD risk. However, prospective cohort studies are warranted to confirm the causal effects of the micronutrients on CVD and its types.

Elevated Serum Copper, Zinc, Selenium, and Lowered α-Klotho Associations: Findings from NHANES 2011-2016 Dataset

The α-Klotho is crucial for human health and longevity. However, the relationship between trace elements and α-Klotho levels needs further investigation. We aimed to explore the relationship between serum levels of selenium (Se), copper (Cu), and zinc (Zn), and serum α-Klotho levels. We analyzed 2138 samples from the 2011-2016 National Health and Nutrition Examination Survey, and the weighted linear regression, WQS, and qgcomp models were utilized to evaluate the effects of these elements on serum α-Klotho levels, individually and combined. A negative correlation was observed between serum Cu concentration and serum α-Klotho levels (β =  - 0.128, 95% CI - 0.196, - 0.059), with each increase in Cu concentration grade showing a gradual decrease in serum α-Klotho levels (Ptrend = 0.002). The WQS model exhibited a negative correlation between the combined effect of Se, Cu, and Zn and serum α-Klotho levels (β =  - 0.035, 95%CI - 0.060, - 0.010), consistently in males (β =  - 0.038 (- 0.059, - 0.017)) and in the 40-49 age group (β =  - 0.059, 95% CI - 0.119, - 0.012). The qgcomp model mirrored these findings, showing a negative correlation in the combined effect index of Se, Cu, and Zn with serum α-Klotho levels (β =  - 0.027, 95% CI - 0.047, - 0.006), consistent in females (β =  - 0.032, 95% CI - 0.061, - 0.004) and in individuals with BMI ≥ 25 (β =  - 0.030, 95% CI - 0.054, - 0.006), and in the 40-49 age group (β =  - 0.047, 95% CI - 0.088, - 0.006). Elevated serum Cu levels may be associated with lower serum α-Klotho levels. The combined effect of serum Se, Cu, and Zn shows a negative correlation with serum α-Klotho levels, with Cu contributing the most. Our findings provide significant insights into assessing the role of trace nutrients in maintaining human health.

Nutritional Support: The Use of Antioxidants in Inflammatory Bowel Disease

The problem of treating inflammatory bowel disease continues to be a topic of great interest for researchers. Despite the complexity surrounding their treatment and strategies to prolong periods of remission, there is a promising exploration of various compounds that have potential in combating inflammation and alleviating symptoms. Selenium, calcium, magnesium, zinc, and iron are among these compounds, offering a glimpse of hope in the treatment of IBD. These essential minerals not only hold the promise of reducing inflammation in these diseases, but also show the potential to enhance immune function and possibly influence the balance of intestinal microflora. By potentially modulating the gut microbiota, they may help support overall immune health. Furthermore, these compounds could play a crucial role in mitigating inflammation and minimising complications in patients with IBD. Furthermore, the protective effect of these compounds against mucosal damage in IBD and the protective effect of calcium itself against osteoporosis in this group of patients are notable.

Nanoselenium attenuates renal ischemia-reperfusion injury in rats

Using selenium (Se) nanoparticles has received attention in recent years because of their therapeutic benefits due to their anticancer, antioxidant, anti-inflammatory, and anti-diabetic effects. This research was conducted to evaluate the possible protective impact of nano-Se on renal unilateral ischemia/reperfusion injury (uIRI) in adult male Wistar rats. Using clamping of the left renal pedicle within 45 min uIRI was induced. The animals were randomly divided into nine groups of control, nano-Se (0.25, 0.5, and 1 mg/kg bw/day) alone, uIRI control, and uIRI rats administrated with nano-Se. At 30 days after treatment, the animals were sacrificed to be assessed biochemically and histopathologically. Nano-Se in uIRI groups have significantly decreased serum creatinine, urea levels, renal histological damage, and increased antioxidant status. Also, our findings demonstrated that the administration of nano-Se caused a significant decrease in the immunoreactivity level of the epidermal growth factor (EGF) and EGFR expression (EGF receptor) in the renal tissue of the uIRI rats. Therefore, nano-Se possesses renoprotective effects, and this effect might be attributable to its antioxidant and free radical scavenger effects. These renoprotective effects may depend on the decreased EGF immunoreactivity level and EGFR expression in the kidney tissue and improve the structure of the kidney tissue. Thus, our research provided biochemical and histological data supporting the potential clinical use of nano-Se for the treatment of certain kidney disorders.

The effect of selenium supplementation on disease activity and immune-inflammatory biomarkers in patients with mild-to-moderate ulcerative colitis: a randomized, double-blind, placebo-controlled clinical trial

PURPOSE

Selenium (Se) supplementation may help reduce inflammation and disease activity in ulcerative colitis (UC) patients. We investigated the therapeutic effects of Se administration in cases with mild-to-moderate active UC.

METHODS

A multicenter, double-blind, randomized clinical trial (RCT) was conducted on 100 cases with active mild-to-moderate UC. The patients were randomly allocated to be given an oral selenomethionine capsule (200 mcg/day, n = 50) or a placebo capsule (n = 50) for 10 weeks. The primary outcome was defined as disease activity via the Simple Clinical Colitis Activity Index (SCCAI), and secondary outcomes were measured at the end of the study.

RESULTS

After 10 weeks, the SCCAI score's mean was reduced in the Se group (P < 0.001). At the end of the intervention, clinical improvement (decline of 3 ≥ score from baseline score) was observed in 19 patients (38%) of the Se group and 3 patients (6%) of the placebo group. The patients with clinical remission (defined as SCCAI ≤ 2) were assigned in the Se group (P = 0.014). The Se group's quality of life and Se serum levels were enhanced at the end of the study (P < 0/001). In the Se group, the mean concentration of interleukin-17 decreased (P < 0/001). However, the levels of interleukin-10 showed no considerable change between the two groups in the 10th week (P = 0.23).

CONCLUSION

Se supplementation as add-on therapy with medical management induced remission and improved the quality of life in patients with active mild-to-moderate UC.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

IRCT20091114002709N51; 2020-04-13.

Exploring the potential function of trace elements in human health: a therapeutic perspective

A trace element, known as a minor element, is a chemical element whose concentration is very low. They are divided into essential and non-essential classes. Numerous physiological and metabolic processes in both plants and animals require essential trace elements. These essential trace elements are so directly related to the metabolic and physiologic processes of the organism that either their excess or deficiency can result in severe bodily malfunction or, in the worst situations, death. Elements can be found in nature in various forms and are essential for the body to carry out its varied functions. Trace elements are crucial for biological, chemical, and molecular cell activity. Nutritional deficits can lead to weakened immunity, increased susceptibility to oral and systemic infections, delayed physical and mental development, and lower productivity. Trace element enzymes are involved in many biological and chemical processes. These compounds act as co-factors for a number of enzymes and serve as centers for stabilizing the structures of proteins and enzymes, allowing them to mediate crucial biological processes. Some trace elements control vital biological processes by attaching to molecules on the cell membrane's receptor site or altering the structure of the membrane to prevent specific molecules from entering the cell. Some trace elements are engaged in redox reactions. Trace elements have two purposes. They are required for the regular stability of cellular structures, but when lacking, they might activate alternate routes and induce disorders. Therefore, thoroughly understanding these trace elements is essential for maintaining optimal health and preventing disease.

Role of micronutrients in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an autoimmune intestinal disease that includes ulcerative colitis, Crohn's disease, and indeterminate colitis. Patients with IBD are often at risk for malnutrition, including micronutrient deficiencies, due to dietary restrictions and poor intestinal absorption. Micronutrients, including vitamins and minerals, play an important role in the human body's metabolism and maintenance of tissue functions. This article reviews the role of micronutrients in IBD. Micronutrients can affect the occurrence and progression of IBD by regulating immunity, intestinal flora, oxidative stress, intestinal barrier function, and other aspects. Monitoring and timely supplementation of micronutrients are important to delay progression and improve clinical symptoms in IBD patients.

SELENOP modifies sporadic colorectal carcinogenesis and WNT signaling activity through LRP5/6 interactions

Although selenium deficiency correlates with colorectal cancer (CRC) risk, the roles of the selenium-rich antioxidant selenoprotein P (SELENOP) in CRC remain unclear. In this study, we defined SELENOP's contributions to sporadic CRC. In human single-cell cRNA-Seq (scRNA-Seq) data sets, we discovered that SELENOP expression rose as normal colon stem cells transformed into adenomas that progressed into carcinomas. We next examined the effects of Selenop KO in a mouse adenoma model that involved conditional, intestinal epithelium-specific deletion of the tumor suppressor adenomatous polyposis coli (Apc) and found that Selenop KO decreased colon tumor incidence and size. We mechanistically interrogated SELENOP-driven phenotypes in tumor organoids as well as in CRC and noncancer cell lines. Selenop-KO tumor organoids demonstrated defects in organoid formation and decreases in WNT target gene expression, which could be reversed by SELENOP restoration. Moreover, SELENOP increased canonical WNT signaling activity in noncancer and CRC cell lines. In defining the mechanism of action of SELENOP, we mapped protein-protein interactions between SELENOP and the WNT coreceptors low-density lipoprotein receptor-related proteins 5 and 6 (LRP5/6). Last, we confirmed that SELENOP-LRP5/6 interactions contributed to the effects of SELENOP on WNT activity. Overall, our results position SELENOP as a modulator of the WNT signaling pathway in sporadic CRC.

Selenoprotein W Ameliorates Experimental Colitis and Promotes Intestinal Epithelial Repair

Selenoprotein W (Selenow) is a ~9 kDa selenoprotein suggested to play a beneficial role in resolving inflammation. However, the underlying mechanisms are poorly understood. SELENOW expression in the human GI tract using ScRNAseq Gut Cell Atlas and Gene Expression Omnibus (GEO) databases revealed its expression in the small intestine and colonic epithelial, endothelial, mesenchymal, and stem cells and correlated with a protective effect in ulcerative colitis patients. Selenow KO mice treated with 4% dextran sodium sulfate (DSS) showed exacerbated acute colitis, with greater weight loss, shorter colons, and increased fecal occult blood compared to the WT counterparts. Selenow KO mice expressed higher colonic Tnfα, increased Tnfα+ macrophages in the colonic lamina propria, and exhibited loss in epithelial barrier integrity and decreased zonula occludens 1 (Zo-1) expression following DSS treatment. Expression of epithelial cellular adhesion marker (EpCam), yes-associated protein 1 (Yap1), and epidermal growth factor receptor (Egfr) were decreased along with CD24lo cycling epithelial cells in Selenow KO mice. Colonic lysates and organoids confirmed a crosstalk between Egfr and Yap1 that was regulated by Selenow. Overall, our findings suggest Selenow expression is key for efficient resolution of inflammation in experimental colitis that is mediated through the regulation of Egfr and Yap1.

Selenocoxib-3, a novel anti-inflammatory therapeutic effectively resolves colitis

Ulcerative colitis (UC) is an idiopathic, chronic and relapsing colonic inflammatory disease. Despite the involvement of diverse intricate mechanisms, COX mediated inflammatory pathway is crucial in the pathophysiology of colitis. Thus, COX inhibition is imperative for managing colitis-associated inflammation. However, the use of COX inhibitory classical non-steroidal anti-inflammatory drugs (NSAIDs) for inflammation resolution has been linked to sudden increased flare-ups. Therefore, considering the anti-inflammatory and pro-resolution effects of antioxidant and essential trace element Selenium (Se), a Seleno-derivative of Celecoxib called Selenocoxib-3 was characterized and evaluated for its favourable pharmacokinetics, safety margins and anti-inflammatory therapeutic potential in DSS-induced experimental colitis. The serum pharmacokinetic profiling [elimination rate constant (K) and clearance (Cl) and toxicity profiling suggested enhanced efficacy, therapeutic potential and lesser toxicity of Selenocoxib-3 as compared to its parent NSAID Celecoxib. In vivo studies demonstrated that Selenocoxib-3 efficiently resolves the gross morphological signs of DSS-induced colitis such as diarrhoea, bloody stools, weight loss and colon shortening. Further, intestinal damage evaluated by H & E staining and MPO activity suggested of histopathological disruptions, such as neutrophil infiltration, mucodepletion and cryptitis, by Selenocoxib-3. The expression profiles of COX-1/2 demonstrated mitigation of pro-inflammatory mediators thereby promoting anti-inflammatory efficacy of Selenocoxib-3 when compared with Celecoxib. The current study suggests translational applicability of Se-containing novel class of COX inhibitors for efficiently managing inflammatory disorders such as UC.

κ-Selenocarrageenan Oligosaccharides Prepared by Deep-Sea Enzyme Alleviate Inflammatory Responses and Modulate Gut Microbiota in Ulcerative Colitis Mice

κ-Selenocarrageenan (KSC) is an organic selenium (Se) polysaccharide. There has been no report of an enzyme that can degrade κ-selenocarrageenan to κ-selenocarrageenan oligosaccharides (KSCOs). This study explored an enzyme, κ-selenocarrageenase (SeCar), from deep-sea bacteria and produced heterologously in Escherichia coli, which degraded KSC to KSCOs. Chemical and spectroscopic analyses demonstrated that purified KSCOs in hydrolysates were composed mainly of selenium-galactobiose. Organic selenium foods through dietary supplementation could help regulate inflammatory bowel diseases (IBD). This study discussed the effects of KSCOs on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in C57BL/6 mice. The results showed that KSCOs alleviated the symptoms of UC and suppressed colonic inflammation by reducing the activity of myeloperoxidase (MPO) and regulating the unbalanced secretion of inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10). Furthermore, KSCOs treatment regulated the composition of gut microbiota, enriched the genera Bifidobacterium, Lachnospiraceae_NK4A136_group and Ruminococcus and inhibited Dubosiella, Turicibacter and Romboutsia. These findings proved that KSCOs obtained by enzymatic degradation could be utilized to prevent or treat UC.

Synthesis, Characterization of Low Molecular Weight Chitosan Selenium Nanoparticles and Its Effect on DSS-Induced Ulcerative Colitis in Mice

Selenium nanoparticles have attracted extensive attention due to their good bioavailability and activity. In the present study, a new form of selenium nanoparticle (Low molecular weight chitosan selenium nanoparticles (LCS-SeNPs)) were synthesized in a system of sodium selenite and acetic acid. The size, element state, morphology and elementary composition of LCS-SeNPs were characterized by using various spectroscopic and microscopic measurements. The protection of LCS-SeNPs against dextran sulfate sodium (DSS)-induced intestinal barrier dysfunction and the inherent mechanisms of this process were investigated. The results showed that LCS-SeNPs, with an average diameter of 198 nm, zero-valent and orange-red relatively uniform spherical particles were prepared. LCS-SeNPs were mainly composed of C, N, O and Se elements, of which Se accounted for 39.03% of the four elements C, N, O and Se. LCS-SeNPs reduced colon injury and inflammation symptoms and improved intestinal barrier dysfunction. LCS-SeNPs significantly reduced serum and colonic inflammatory cytokines TNF-α and IL-6 levels. Moreover, LCS-SeNPs remarkably increased antioxidant enzyme GSH-Px levels in serum and colonic tissue. Further studies on inflammatory pathways showed that LCS-SeNPs alleviated DSS-induced colitis through the NF-κB signaling pathway, and relieved inflammatory associated oxidative stress through the Nrf2 signaling pathway. Our findings suggested that LCS-SeNPs are a promising selenium species with potential applications in the treatment of oxidative stress related inflammatory intestinal diseases.

Phragmites rhizoma polysaccharide-based nanocarriers for synergistic treatment of ulcerative colitis

The purpose of this study was to construct Phragmites rhizoma polysaccharide-based nano-drug delivery systems (PRP2-SeNPs-H/Aza-Lips) for synergistically alleviating ulcerative colitis and to investigate the important roles of Phragmites rhizoma polysaccharide-based nanocarriers in PRP2-SeNPs-H/Aza-Lips. Phragmites rhizoma polysaccharide (PRP2) was isolated and used for the preparation of Phragmites rhizoma polysaccharide selenium nanoparticles with low selenium content (PRP2-SeNPs-L) and high selenium content (PRP2-SeNPs-H). Based on the electrostatic attraction between PRP2-SeNPs-H and azathioprine liposomes (Aza-Lips), PRP2-SeNPs-H/Aza-Lips were constructed for precise delivery of the model drug azathioprine (Aza) to colon lesions. Results showed that PRP2 significantly alleviated the clinical symptoms and colon tissue damage and down-regulated the levels of inflammatory factors in serum and colon, demonstrating beneficial effects on mice with ulcerative colitis. PRP2-SeNPs-L had better relieving effects on ulcerative colitis. Phragmites rhizoma polysaccharide-based nanocarriers may protect azathioprine liposomes against gastrointestinal digestion, enhance the therapeutic effects on ulcerative colitis, and significantly reduce liver damage from azathioprine, which helps to improve the efficacy and toxicity of clinical drugs.

The Burden of Cancer, Government Strategic Policies, and Challenges in Pakistan: A Comprehensive Review

Cancer is a severe condition characterized by uncontrolled cell division and increasing reported mortality and diagnostic cases. In 2040, an estimated 28.4 million cancer cases are expected to happen globally. In 2020, an estimated 19.3 million new cancer cases (18.1 million excluding non-melanoma skin cancer) had been diagnosed worldwide, with around 10.0 million cancer deaths. Breast cancer cases have increased by 2.26 million, lung cancer by 2.21 million, stomach by 1.089 million, liver by 0.96 million, and colon cancer by 1.93 million. Cancer is becoming more prevalent in Pakistan, with 19 million new cancer cases recorded in 2020. Food adulteration, gutkha, paan, and nutritional deficiencies are major cancer risk factors that interplay with cancer pathogenesis in this country. Government policies and legislation, cancer treatment challenges, and prevention must be revised seriously. This review presents the current cancer epidemiology in Pakistan to better understand cancer basis. It summarizes current cancer risk factors, causes, and the strategies and policies of the country against cancer.

Selenium-containing tea polysaccharides ameliorate DSS-induced ulcerative colitis via enhancing the intestinal barrier and regulating the gut microbiota

Both tea polysaccharides and selenium have certain remission potential for ulcerative colitis (UC), but few reports focused on natural selenium-containing tea polysaccharides. The purpose of this study was to isolate a selenium-containing tea polysaccharide (ASeTP) and determine its structure and effects on UC. Results showed that ASeTP was primarily composed of three purified, β-pyranoside-linked, protein-binding polysaccharides (SeTP-1, SeTP-2, and SeTP-3) with SeOC, OSeO, and SeO linkages. Specifically, SeTP-1 was a neutral heteropolysaccharide principally composed of mannose, glucose, galactose, xylose, and arabinose, while SeTP-2 and SeTP-3 were acidic heteropolysaccharides due to the existence of glucuronic acid. ASeTP effectively alleviated the symptoms of weight loss, colon shortens, and disease activity index scores increase in dextran sodium sulfate (DSS)-induced colitis mice. ASeTP attenuated the histological damage and maintained the colonic mucosal barrier via up-regulating the expression of occludin, claudin-1, and zona occludens-1 (ZO-1). ASeTP suppressed the levels of pro-inflammatory cytokines and enhanced the antioxidant capacity of colon tissue. Besides, ASeTP beneficially increased the selenium content of the colon. Furthermore, ASeTP remodeled the gut microbiota by accelerating the proliferation of beneficial bacteria and inhibiting pathogenic microorganisms. Thus, ASeTP has the potential to be a functional food against colitis.

PRKAR2A-derived circular RNAs promote the malignant transformation of colitis and distinguish patients with colitis-associated colorectal cancer

BACKGROUND

Emerging studies have proved that colonic inflammation caused by refractory inflammatory bowel disease (IBD) can initiate the colitis-associated cancer (CAC), but the transition from inflammation to carcinoma is still largely unknown.

METHODS

In this study, mouse colitis and CAC models were established, and the RNA-seq by circRNA microarray was employed to identify the differentially expressed circRNAs and mRNAs in different comparisons (DSS vs. NC and AOM/DSS vs. DSS). The bioinformatics analyses were used to search the common characteristics in mouse colitis and CAC.

RESULTS

The K-means clustering algorithm packaged these differential expressed circRNAs into subgroup analysis, and the data strongly implied that mmu_circ_0001109 closely correlated to the pro-inflammatory signals, while mmu_circ_0001845 was significantly associated with the Wnt signalling pathway. Our subsequent data in vivo and in vitro confirmed that mmu_circ_0001109 could exacerbate the colitis by up-regulating the Jak-STAT3 and NF-kappa B signalling pathways, and mmu_circ_0001845 promoted the CAC transformation through the Wnt signalling pathway. By RNA blasting between mice and humans, the human RTEL1- and PRKAR2A-derived circRNAs, which might be considered as homeotic circRNAs of mmu_circ_0001109 and mmu_circ_0001845, respectively, were identified. The clinical data revealed that RTEL1-derived circRNAs had no clinical significance in human IBD and CAC. However, three PRKAR2A-derived circRNAs, which had the high RNA similarities to mmu_circ_0001845, were remarkably up-regulated in CAC tissue samples and promoted the transition from colitis to CAC.

CONCLUSIONS

Our results suggested that these human PRKAR2A-derived circRNAs could be novel candidates for distinguishing CAC patients and predicted the prognosis of CAC.

Supplementary selenium in the form of selenylation α-D-1,6-glucan ameliorates dextran sulfate sodium induced colitis in vivo

The deficiency of selenium has been found in clinical IBD patients and supplementation selenium is recognized as beneficial for colitis treatment. In this study, an organic selenium compound-selenylation α-D-1,6-glucan (sCPA) was prepared, and the effect of sCPA on DSS induced colitis mice was investigated. The results suggested that sCPA prevented the weight loss, colon length shortening, and stool loose of colitis mice. It protected colon mucosal barrier by promoting tight junction protein ZO-1 and Occludin expression. Moreover, sCPA reduced oxidative stress via regulating SOD and MDA levels, and decreased the contents of inflammatory proteins NF-κB and NLRP3 and adjusted TNF-α, IFN-γ, IL-1β, and IL-10 inflammatory cytokines. Furthermore, sCPA repaired intestinal microbiota composition especially Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria that altered by DSS in colitis mice. Meanwhile, SCFAs produced by gut microbiota were restored by sCPA close to the level in the normal group. In conclusion, these findings indicated that the sCPA might be a potential dietary selenium supplementation for the prevention and treatment of colitis.

A Pan-Cancer Analysis of the Role of Selenoprotein P mRNA in Tumorigenesis

Background

Selenium (Se) exhibits its anti-carcinogenic properties by regulating the redox system. However, the relationship between selenoprotein P (SeP), mRNA (SELENOP mRNA) and tumorigenesis remains unclear. Plasma SeP transports Se to various target tissues and has antioxidant characteristics. The present study aimed to explore the multifaceted pan-cancer properties of SELENOP in terms of its tissue-specific expression, prognostic value, immune function, and signaling pathway enrichment.

Patients and Methods

The expression profile of SELENOP was determined in 33 tumor types and survival, pathway enrichment, and correlation analyses were conducted based on TCGA database. The relationship between SELENOP expression and immune infiltration and macrophage subtype gene markers was investigated using the TIMER and GEPIA.

Results

SELENOP gene expression was decreased in many cancer tissues, but was upregulated in brain lower grade glioma (LGG). Furthermore, SELENOP expression was associated with a better prognosis in most cancers, but a poorer prognosis in LGG and uterine corpus endometrioid carcinoma (UCEC). Our results showed that SELENOP was correlated with infiltration level of six immune cell types, where SELENOP also showed a strong correlation with macrophages in some cancer types. However, we failed to determine macrophage polarization in 33 tumor types. SELENOP negatively regulated vascular endothelial cell proliferation in LGG and UCEC and epidermal cell differentiation in six tumor types. In contrast, upregulation was related to immune function, including T cell activation, B cell-mediated immunity, adaptive immune response and immune response regulation cell surface receptor signaling pathways in another six tumor types.

Conclusion

These findings highlighted the tissue-specific expression, prognostic value and immune characteristics of SELENOP in pan-cancer, and provided insights for illustrating the role of SELENOP in tumorigenesis.

Selenium deficiency induced apoptosis via mitochondrial pathway caused by Oxidative Stress in porcine gastric tissues

Selenium (Se) is an essential nutrient for the body, which can ensure GSH-Px activity and has antioxidant effect. Se deficiency may lead to apoptosis in various tissues and organs in animals. Pigs as major livestock in the farming industry, Se deficiency can cause various types of diseases such as white muscle disease, and mulberry heart disease.The aim of this experiment was to investigate the effect and mechanism of Se deficiency on apoptosis in porcine gastric tissue. Forty weaned piglets were randomly divided into Se deficiency group and control group, and fed with low Se diet and normal diet for six weeks respectively. The histochemical characteristics, antioxidant indexes, apoptotic genes and apoptotic protein expression of gastric cells in Se-deficient piglets were detected. The results of antioxidant index, TUNEL, RT-PCR and Western blot showed that Se deficiency decreased the activities of CAT, SOD and GSH-Px, increased the apoptotic rate of porcine gastric tissue, increased the expression of Bax and Caspase-3, and decreased the expression of Bcl-2. The results demonstrated that Se deficiency could induce apoptosis in porcine gastric tissue cells through oxidative stress-induced mitochondrial pathway. The stomach was a key target of Se deficiency and may play a key role in the response to Se deficiency. Our study may provide new ideas for the prevention and treatment of swine gastric diseases caused by Se deficiency and is beneficial to the development of pig farming industry.

Trace Element Selenium Effectively Alleviates Intestinal Diseases

Selenium (Se) is an essential trace element in the body. It is mainly used in the body in the form of selenoproteins and has a variety of biological functions. Intestinal diseases caused by chronic inflammation are among the most important threats to human health, and there is no complete cure at present. Due to its excellent antioxidant function, Se has been proven to be effective in alleviating intestinal diseases such as inflammatory bowel diseases (IBDs). Therefore, this paper introduces the role of Se and selenoproteins in the intestinal tract and the mechanism of their involvement in the mediation of intestinal diseases. In addition, it introduces the advantages and disadvantages of nano-Se as a new Se preparation and traditional Se supplement in the prevention and treatment of intestinal diseases, so as to provide a reference for the further exploration of the interaction between selenium and intestinal health.

Emerging Pathological Engagement of Ferroptosis in Gut Diseases

Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is mainly characterized by chronic and progressive inflammation that damages the gastrointestinal mucosa. Increasing studies have enlightened that dysregulated cell death occurs in the inflamed sites, leading to the disruption of the intestinal barrier and aggravating inflammatory response. Ferroptosis, a newly characterized form of regulated cell death, is driven by the lethal accumulation of lipid peroxides catalyzed by cellular free iron. It has been widely documented that the fundamental features of ferroptosis, including iron deposition, GSH exhaustion, GPX4 inactivation, and lipid peroxidation, are manifested in the injured gastrointestinal tract in IBD patients. Furthermore, manipulation of the critical ferroptotic genes could alter the progression, severity, or even morbidity of the experimental colitis. Herein, we critically summarize the recent advances in the field of ferroptosis, focusing on interpreting the potential engagement of ferroptosis in the pathogenesis of IBD. Moreover, we are attempting to shed light on a perspective insight into the possibility of targeting ferroptosis as novel therapeutic designs for the clinical intervention of these gastrointestinal diseases.

Selenium and the 15kDa Selenoprotein Impact Colorectal Tumorigenesis by Modulating Intestinal Barrier Integrity

Selenoproteins play important roles in many cellular functions and biochemical pathways in mammals. Our previous study showed that the deficiency of the 15 kDa selenoprotein (Selenof) significantly reduced the formation of aberrant crypt foci (ACF) in a mouse model of azoxymethane (AOM)-induced colon carcinogenesis. The objective of this study was to examine the effects of Selenof on inflammatory tumorigenesis, and whether dietary selenium modified these effects. For 20 weeks post-weaning, Selenof-knockout (KO) mice and littermate controls were fed diets that were either deficient, adequate or high in sodium selenite. Colon tumors were induced with AOM and dextran sulfate sodium. Surprisingly, KO mice had drastically fewer ACF but developed a similar number of tumors as their littermate controls. Expression of genes important in inflammatory colorectal cancer and those relevant to epithelial barrier function was assessed, in addition to structural differences via tissue histology. Our findings point to Selenof's potential role in intestinal barrier integrity and structural changes in glandular and mucin-producing goblet cells in the mucosa and submucosa, which may determine the type of tumor developing.

Colonic Epithelial-Derived Selenoprotein P Is the Source for Antioxidant-Mediated Protection in Colitis-Associated Cancer

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) demonstrate nutritional selenium deficiencies and are at greater risk of developing colon cancer. Previously, we determined that global reduction of the secreted antioxidant selenium-containing protein, selenoprotein P (SELENOP), substantially increased tumor development in an experimental colitis-associated cancer (CAC) model. We next sought to delineate tissue-specific contributions of SELENOP to intestinal inflammatory carcinogenesis and define clinical context.

METHODS

Selenop floxed mice crossed with Cre driver lines to delete Selenop from the liver, myeloid lineages, or intestinal epithelium were placed on an azoxymethane/dextran sodium sulfate experimental CAC protocol. SELENOP loss was assessed in human ulcerative colitis (UC) organoids, and expression was queried in human and adult UC samples.

RESULTS

Although large sources of SELENOP, both liver- and myeloid-specific Selenop deletion failed to modify azoxymethane/dextran sodium sulfate-mediated tumorigenesis. Instead, epithelial-specific deletion increased CAC tumorigenesis, likely due to elevated oxidative stress with a resulting increase in genomic instability and augmented tumor initiation. SELENOP was down-regulated in UC colon biopsies and levels were inversely correlated with endoscopic disease severity and tissue S100A8 (calprotectin) gene expression.

CONCLUSIONS

Although global selenium status is typically assessed by measuring liver-derived plasma SELENOP levels, our results indicate that the peripheral SELENOP pool is dispensable for CAC. Colonic epithelial SELENOP is the main contributor to local antioxidant capabilities. Thus, colonic SELENOP is the most informative means to assess selenium levels and activity in IBD patients and may serve as a novel biomarker for UC disease severity and identify patients most predisposed to CAC development.

The rationale for selenium supplementation in inflammatory bowel disease: A mechanism-based point of view

Management of inflammatory bowel disease (IBD) has always been a challenge for physicians. Current treatment protocols may cause numerous adverse effects. Selenium is known for its putative antiinflammatory properties. Selenium is needed for the biosynthesis of enzymatically active selenoproteins, which contribute to antioxidative defense, and effective function of immune systems. Several studies have shown that patients with IBD have a lower selenium level compared to healthy subjects. Hence, experimental studies mimicking ulcerative colitis and Crohn's disease investigated the effect of selenium supplementation on IBD. Previous studies indicated the following: 1) Selenoproteins can curb the inflammatory response and attenuate oxidative stress. This antiinflammatory property caused remission in animal models of colitis. 2) Selenium supports protective gut microbiota, which indirectly improves management of IBD. 3) Selenium may block some of the predominant tumorigenesis pathways proposed in colitis-associated colorectal cancer. 4) Selenium supplementation showed promising results in preliminary clinical studies, particularly in patients with selenium deficiency. While selenium supplementation seems to be beneficial for IBD, clinical studies have remained too preliminary in this regard. Randomized clinical trials are needed to measure the short-term and long-term effects of selenium on both active and quiescent IBD, particularly in patients with IBD who have documented selenium deficiency.

Preparation, characterization, and in vivo evaluation of anti-inflammatory activities of selenium nanoparticles synthesized by Kluyveromyces lactis GG799

Selenium (Se) is an essential micronutrient that has implications in human diseases, including inflammatory bowel disease (IBD), especially with respect to Se deficiencies. Recently, selenium nanoparticles (SeNPs) have attracted significant attention due to their diversity of biological activities and unique advantages including low toxicity and high biological availability. In this study, an eco-friendly, efficient and low-cost method for synthesis of SeNPs by Kluyveromyces lactis GG799 (K. lactis GG799) was established, and the SeNPs were investigated for their physicochemical properties and anti-inflammatory activities in vivo. K. lactis GG799 was able to successfully transform sodium selenite into bright-red SeNPs with particle sizes of 80 and 150 nm and the nanoparticles accumulated intracellularly. Upon isolation, the SeNPs were found to be mainly capped by proteins and polysaccharides by components analysis. Dietary supplementation with 0.6 mg kg-1 Se (in the form of biogenic SeNPs) effectively attenuated dextran sulphate sodium (DSS)-induced ulcerative colitis (UC) in mice by alleviating oxidative stress and intestinal inflammation. These findings suggested that SeNPs synthesized by K. lactis GG799 may be a promising and safe Se supplement for the prevention and treatment of IBD.

Maternal organic selenium supplementation during gestation improves the antioxidant capacity and reduces the inflammation level in the intestine of offspring through the NF-κB and ERK/Beclin-1 pathways

Selenium (Se) is postulated to protect against inflammation in the gut by attenuating oxidative stress. This study was conducted to investigate the effects of maternal 2-hydroxy-4-methylselenobutanoic acid (HMSeBA), an organic Se source, on the intestinal antioxidant capacity and inflammation level of the offspring and its possible mechanism. Forty-three sows were randomly assigned to receive one of the following three diets during gestation: control diet, sodium selenite (Na₂SeO₃) supplemented diet or HMSeBA supplemented diet, respectively. Samples were collected from the offspring at birth and weaning. The results showed that maternal HMSeBA supplementation significantly upregulated ileal GPX2 and SePP1 gene expression compared with the control and Na₂SeO₃ groups, while suppressed the expression of ileal IL-1β, IL-6 and NF-κB genes in newborn piglets compared with the control group. Moreover, maternal HMSeBA supplementation significantly increased the protein of ileal GPX2 and p-mTOR compared with the control and Na₂SeO₃ groups, but decreased the ileal p-NF-κB, Beclin-1 and p-ERK proteins in newborn piglets compared with the control group. The weaned piglets of the HMSeBA group had lower serum IL-1β and IL-6 than the piglets of the control group at 2 h of LPS challenge. In addition, after the LPS challenge, the HMSeBA group had a lower relative abundance of ileal p-NF-κB and Beclin-1 proteins than the control and Na₂SeO₃ groups. In conclusion, maternal HMSeBA supplementation during gestation can improve the offspring's intestinal antioxidant capacity and reduce the inflammation level by suppressing NF-κB and ERK/Beclin-1 signaling.

Selenium Deficiency in Chickens Induces Intestinal Mucosal Injury by Affecting the Mucosa Morphology, SIgA Secretion, and GSH-Px Activity

The small intestine is one of the target organs of dietary selenium (Se) deficiency. Our objective was to investigate the effects of Se deficiency on small intestinal mucosa morphology and function in chickens. In the present study, 1-day (d)-old chickens were fed either a commercial diet with 0.15 mg/kg Se (control group) or a Se-deficient diet with 0.016 mg/kg Se (Se-group). The average daily weight gain, Se content in the blood, secretory immunoglobulin A (SIgA) secretion, and glutathione peroxidase (GSH-Px) activity in the small intestine in chickens were examined after 10, 20, 30, and 40 days of feeding. We also observed the morphology of the small intestine and recorded the number of intraepithelial lymphocytes (IELs). The average daily weight gain decreased; the level of Se in the blood decreased significantly; and SIgA secretion and GSH-Px activity in the duodenum, jejunum, and ileum decreased to different degrees. Histological analysis showed that the villus length, crypt depth, mucosal thickness, and number of IELs in the small intestine decreased to different extents in different periods. In the Se-group, longer feeding times were associated with more severe injury to physiological structure and function in the intestinal mucosa in chickens. In conclusion, Se deficiency induced injury of the mucosal immune barrier and physical barrier of the small intestine, and decreased the growth performance and antioxidant capacity in chickens.

The Essential Role of Selenoproteins in the Resolution of Citrobacter rodentium-Induced Intestinal Inflammation

Enteropathogenic Escherichia coli (EPEC) leads to adverse colonic inflammation associated with poor resolution of inflammation and loss of epithelial integrity. Micronutrient trace element selenium (Se) is incorporated into selenoproteins as the 21st amino acid, selenocysteine (Sec). Previous studies have shown that such an incorporation of Sec into the selenoproteome is key for the anti-inflammatory functions of Se in macrophages and other immune cells. An intriguing mechanism underlying the anti-inflammatory and pro-resolving effects of Se stems from the ability of selenoproteins to skew arachidonic acid metabolism from pro-inflammatory mediators, prostaglandin E₂ (PGE₂) toward anti-inflammatory mediators derived from PGD₂, such as 15-deoxy-Δ^{12, 14}- prostaglandin J₂ (15d-PGJ₂), via eicosanoid class switching of bioactive lipids. The impact of Se and such an eicosanoid-class switching mechanism was tested in an enteric infection model of gut inflammation by C. rodentium, a murine equivalent of EPEC. C57BL/6 mice deficient in Se (Se-D) experienced higher mortality when compared to those on Se adequate (0.08 ppm Se) and Se supplemented (0.4 ppm Se) diets following infection. Decreased survival was associated with decreased group 3 innate lymphoid cells (ILC3s) and T helper 17 (Th17) cells in colonic lamina propria of Se-D mice along with deceased expression of epithelial barrier protein Zo-1. Inhibition of metabolic inactivation of PGE₂ by 15-prostaglandin dehydrogenase blocked the Se-dependent increase in ILC3 and Th17 cells in addition to reducing epithelial barrier integrity, as seen by increased systemic levels of FITC-dextran following oral administration; while 15d-PGJ₂ administration in Se-D mice alleviated the effects by increasing ILC3 and Th17 cells. Mice lacking selenoproteins in monocyte/macrophages via the conditional deletion of the tRNA^[Sec] showed increased mortality post infection. Our studies indicate a crucial role for dietary Se in the protection against inflammation following enteric infection via immune mechanisms involving epithelial barrier integrity.

Selenium deficiency induced necroptosis, Th1/Th2 imbalance, and inflammatory responses in swine ileum

Selenium (Se) deficiency has a significant impact on the swine breeding industry by inducing digestive system damage and diarrhea. However, the molecular mechanism remains unclear. Our objectives were to investigate if different amounts of necroptosis, inflammatory responses, and T helper cell 1/T helper cell 2 (Th1/Th2) imbalances were induced by Se deficiency in intestinal porcine jejunal epithelial cells (IPEC-J2) and swine ileum tissue. Therefore, Se-deficient models were successfully established both in vitro and in vivo. In the current study, the cell morphological observation results showed that Se deficiency seriously affected the growth and differentiation of IPEC-J2 cells. Moreover, the necroptosis staining and histomorphology observation results showed that the number of necroptotic cells increased significantly, and the ileal tissue exhibited abnormal structures, including necroptotic features and inflammatory cell infiltration, in the Se-deficient group. Furthermore, Se deficiency resulted in accelerated cell necroptosis by increasing (p < .05) the expression of genes related to the tumor necrosis factor-α pathway at both the protein and messenger RNA (mRNA) levels compared to the control group. Moreover, the relative mRNA and protein expression of the inflammatory genes and their responses to dietary Se deficiency were consistent with the resultant Th1/Th2 imbalances in vitro and in vivo. Taken together, the results suggested that Se deficiency caused necroptosis, inflammatory responses, and abnormal expression of cytokines in swine ileum tissue. These findings might help us to explain the damage induced by Se deficiency to the digestive system of swine.

Selenium Donors at the Junction of Inflammatory Diseases

Selenium is an essential non-metal trace element, and the imbalance in the bioavailability of selenium is associated with many diseases ranking from acute respiratory distress syndrome, myocardial infarction and renal failure (Se overloading) to diseases associated with chronic inflammation like inflammatory bowel diseases, rheumatoid arthritis, and atherosclerosis (Se unload). The only source of selenium is the diet (animal and cereal sources) and its intestinal absorption is limiting for selenocysteine and selenomethionine synthesis and incorporation in selenoproteins. In this review, after establishing the link between selenium and inflammatory diseases, we envisaged the potential of selenium nanoparticles and organic selenocompounds to compensate the deficit of selenium intake from the diet. With high selenium loading, nanoparticles offer a low dosage to restore selenium bioavailability whereas organic selenocompounds can play a role in the modulation of their antioxidant or antiinflammatory activities.

Impact of dietary manganese on experimental colitis in mice

Diet plays a significant role in the pathogenesis of inflammatory bowel disease (IBD). A recent epidemiological study has shown an inverse relationship between nutritional manganese (Mn) status and IBD patients. Mn is an essential micronutrient required for normal cell function and physiological processes. To date, the roles of Mn in intestinal homeostasis remain unknown and the contribution of Mn to IBD has yet to be explored. Here, we provide evidence that Mn is critical for the maintenance of the intestinal barrier and that Mn deficiency exacerbates dextran sulfate sodium (DSS)-induced colitis in mice. Specifically, when treated with DSS, Mn-deficient mice showed increased morbidity, weight loss, and colon injury, with a concomitant increase in inflammatory cytokine levels and oxidative and DNA damage. Even without DSS treatment, dietary Mn deficiency alone increased intestinal permeability by impairing intestinal tight junctions. In contrast, mice fed a Mn-supplemented diet showed slightly increased tolerance to DSS-induced experimental colitis, as judged by the colon length. Despite the well-appreciated roles of intestinal microbiota in driving inflammation in IBD, the gut microbiome composition was not altered by changes in dietary Mn. We conclude that Mn is necessary for proper maintenance of the intestinal barrier and provides protection against DSS-induced colon injury.

The synergistic effect of Lactobacillus plantarum CCFM242 and zinc on ulcerative colitis through modulating intestinal homeostasis

The beneficial effects of the essential metal zinc (Zn) and probiotics on gut health have been well documented, but how they synergistically affect intestinal physiology is not thoroughly understood. In this study, the Zn-enriching ability of 33 probiotics in a medium or an aqueous solution was evaluated. A Lactobacillus plantarum strain, CCFM242, with a superior Zn-enriching ability was screened. Among the cellular components, the cell wall played the most important role in the Zn binding of L. plantarum CCFM242. The carboxyl and amino groups on the surface of the strain were also vital for Zn enrichment. Upon optimization of the Zn-enriching procedure, the Zn-binding ability of this strain reached 24.89 ± 0.50 mg g^-1 dry biomass. Compared to the treatment of ZnSO₄ or L. plantarum CCFM242, oral supplementation with Zn-enriched L. plantarum CCFM242 resulted in a higher serum Zn level, enhanced levels of mRNA expression of colonic tight junctions, increased levels of short-chain fatty acids (SCFAs) in colonic contents, and stronger modulatory effects on the anti-oxidant and immune defense systems in the gut of normal mice. Zn-Enriched L. plantarum CCFM242 treatment also offered more significant protective effects against dextran sodium sulfate (DSS)-induced colitis in mice compared to the treatment of ZnSO₄ or L. plantarum CCFM242 alone. The synergistic effect of Zn-enriched L. plantarum CCFM242 may be due to the increased tolerance of the strain to the gastrointestinal tract conditions and the higher bioavailability of Zn after the metal-enrichment process.

Micronutrient Absorption and Related Outcomes in People with Inflammatory Bowel Disease: A Review

Inflammatory Bowel Disease (IBD) is a chronic disorder associated with immune dysregulation and chronic inflammation of the digestive tract. While it is poorly understood, the role of nutrition and nutrient status in the etiology of IBD and its associated outcomes has led to increased research relating to micronutrient deficiency. This review offers an overview of recent literature related to micronutrient absorption and outcomes in adults with IBD. Although the absorption and IBD-related outcomes of some micronutrients (e.g., vitamin D and iron) are well understood, other micronutrients (e.g., vitamin A) require further research. Increased research and clinician knowledge of the relationship between micronutrients and IBD may manifest in improved nutrient screening, monitoring, treatment, and outcomes for people living with IBD.

Varied doses and chemical forms of selenium supplementation differentially affect mouse intestinal physiology

Varied doses and chemical forms of selenium supplementation differentially affect mouse intestinal physiology and perturbed the fecal metabolic profiles of and jejunal protein expression in mice.

Knockout of ClC-2 reveals critical functions of adherens junctions in colonic homeostasis and tumorigenicity

Adherens junctions (AJs), together with tight junctions (TJs), form an apical junctional complex that regulates intestinal epithelial cell-to-cell adherence and barrier homeostasis. Within the AJ, membrane-bound E-cadherin binds β-catenin, which functions as an essential intracellular signaling molecule. We have previously identified a novel protein in the region of the apical junction complex, chloride channel protein-2 (ClC-2), that we have used to study TJ regulation. In this study, we investigated the possible effects of ClC-2 on the regulation of AJs in intestinal mucosal epithelial homeostasis and tumorigenicity. Mucosal homeostasis and junctional proteins were examined in wild-type (WT) and ClC-2 knockout (KO) mice as well as associated colonoids. Tumorigenicity and AJ-associated signaling were evaluated in a murine colitis-associated tumor model and in a colorectal cancer cell line (HT-29). Colonic tissues from ClC-2 KO mice had altered ultrastructural morphology of intercellular junctions with reduced colonocyte differentiation, whereas jejunal tissues had minimal changes. Colonic crypts from ClC-2 KO mice had significantly higher numbers of less-differentiated forms of colonoids compared with WT. Furthermore, the absence of ClC-2 resulted in redistribution of AJ proteins and increased β-catenin activity. Downregulation of ClC-2 in colorectal cells resulted in significant increases in proliferation associated with disruption of AJs. Colitis-associated tumors in ClC-2 KO mice were significantly increased, associated with β-catenin transcription factor activation. The absence of ClC-2 results in less differentiated colonic crypts and increased tumorigenicity associated with colitis via dysregulation of AJ proteins and activation of β-catenin-associated signaling. NEW & NOTEWORTHY Disruption of adherens junctions in the absence of chloride channel protein-2 revealed critical functions of these junctional structures, including maintenance of colonic homeostasis and differentiation as well as driving tumorigenicity by regulating β-catenin signaling.

Roles for selenium and selenoprotein P in the development, progression, and prevention of intestinal disease

Selenium (Se) is a micronutrient essential to human health, the function of which is mediated in part by incorporation into a class of proteins known as selenoproteins (SePs). As many SePs serve antioxidant functions, Se has long been postulated to protect against inflammation and cancer development in the gut by attenuating oxidative stress. Indeed, numerous studies over the years have correlated Se levels with incidence and severity of intestinal diseases such as inflammatory bowel disease (IBD) and colorectal cancer (CRC). Similar results have been obtained with the Se transport protein, selenoprotein P (SELENOP), which is decreased in the plasma of both IBD and CRC patients. While animal models further suggest that decreases in Se or SELENOP augment colitis and intestinal tumorigenesis, large-scale clinical trials have yet to show a protective effect in patient populations. In this review, we discuss the function of Se and SELENOP in intestinal diseases and how research into these mechanisms may impact patient treatment.

New Insights into the Role of Trace Elements in IBD

Micronutrient deficiencies are common in inflammatory bowel disease and have clinical impact, being both a sign of complicated disease and a cause of morbidity. The involved systemic inflammatory response is responsible for altering the concentration of a wide range of trace elements in the serum, including zinc and selenium. This review summarizes recent advances and evidence-based knowledge regarding the impact of selenium and zinc on oxidative stress and microbiota changes in IBD patients. Getting new insight into the impact of malnutrition, particularly on the micronutrients' impact on the development, composition, and metabolism of microbiota, as well as the influence of oxidative stress and the mucosal immune response, could help in implementing new management strategies for IBD patients, with focus on a more integrated approach.

The Adverse Effects of Se Toxicity on Inflammatory and Immune Responses in Chicken Spleens

Selenium (Se) is an essential trace element, but excessive intake of Se could induce Se poisoning, and result in various health problems. NF-κB regulated many molecules of the immune response and the inflammatory response, and Th1/Th2 balance played a key in the regulation of immune response. The aim of this study is to investigate the role of NF-κB pathway and Th1/Th2 imbalance in the adverse influence of Se poisoning on chicken spleens. In the current study, 90 chickens were randomly divided into two groups (n = 45 per group). The chickens were maintained either on a basal diet (the control group) containing 0.2 mg/kg Se or a high supplemented diet (the Se group) containing 15 mg/kg Se for 45 days. Then, we observed the pathohistology of spleen cells and detected NO content, iNOS activity, and the expression of NF-κB, iNOS, COX-2, PTGE, IL-6, TNF-α, Foxp3, IL-4, and IFN-γ in chicken spleens. In chicken spleens of the Se group, the result showed typical characteristics of inflammation: the content of NO and the activity of iNOS were increased, and the expression of NF-κB, iNOS, COX-2, PTGE, IL-6, TNF-α, and IL-4 was enhanced and that of Foxp3 and IFN-γ was decreased. Our study showed that Se toxicity could promote inflammation via NF-κB pathway, impairing the immune function, and changing Th1/Th2 balance in the chicken spleens.

Resolution of Cox mediated inflammation by Se supplementation in mouse experimental model of colitis

UC a form of IBD is a chronic inflammatory disorder of large intestine, with unknown etiology. Reports suggest a critical role of COX-2 dependent prostaglandins (PGs) mediated inflammatory pathway in pathophysiology of UC. However, COX inhibition using NSAIDs exacerbate IBD and thus is not a viable solution. Currently, in DSS induced experimental colitis in mice, we have demonstrated that dietary Se supplementation (0.5ppm as sodium selenite) symptomatically resolves the signs of inflammation in a redox sensitive manner as compared to Se deficient (0.01ppm) conditions, as seen by modulation in oxidative stress markers, morphological changes, histopathological examinations, biochemical studies such as MPO activity, activity of intestinal markers enzymes as well as mRNA and expressions of various pro and anti-inflammatory factors such as, mPGES, hPGDS, TXAS, 15-PGDH, GPX-1 and GPX-2. These findings were validated and correlated with changes in the biophysical parameters such as membrane fluidity, electrical parameters (impedance), transport across the colonic tissue and FTIR. Current study not only concluded that Se at supranutritional concentrations by modulating the redox status relieves the signs of colitis by regulating COX dependent PG biosynthetic pathway, but also sheds light on the biophysical characterization of these inflammatory/resolution pathways involved in UC.

Risk Factors for Vitamin D, Zinc, and Selenium Deficiencies in Korean Patients with Inflammatory Bowel Disease

Background/Aims

Studies on the micronutrient status of Asian patients with inflammatory bowel disease (IBD) are scarce. We evaluated the prevalence of micronutrient deficiency and verified the risk factors for micronutrient deficiency in Korean patients with IBD.

Methods

We measured the serum levels of 25-hydroxyvitamin D3 [25-(OH)D], zinc, and selenium to analyze the clinical risk factors for micronutrient levels below the reference values. In addition, we compared the 25-(OH)D levels of patients with IBD to those of age- and sex-matched healthy controls.

Results

Among the 83 patients, 74 (89.2%) had suboptimal serum 25-(OH)D levels. The mean plasma 25-(OH)D level in patients with IBD was significantly reduced compared to that of the healthy controls (12.3±6.2 ng/mL vs 20.0±6.7 ng/mL; p<0.001). The proportions of patients with lower serum zinc and selenium levels were 39.0% and 30.9%, respectively. Female sex (p=0.012) and Crohn’s disease (p=0.012) were associated with vitamin D deficiency. Patients younger than 40 years were at increased risk for zinc deficiency (p=0.045). Female sex (p=0.015) and low serum albumin level (<3.3 g/dL) (p=0.047) were risk factors for selenium deficiency.

Conclusions

Many Korean patients with IBD have vitamin D, zinc, and selenium deficiencies, suggesting the necessity for monitoring levels of these micronutrients.

Selenium and Selenoproteins in Gut Inflammation-A Review

Inflammatory bowel disease (IBD), characterized by severe flares and remissions, is a debilitating condition. While the etiology is unknown, many immune cells, such as macrophages, T cells and innate lymphoid cells, are implicated in the pathogenesis of the disease. Previous studies have shown the ability of micronutrient selenium (Se) and selenoproteins to impact inflammatory signaling pathways implicated in the pathogenesis of the disease. In particular, two transcription factors, nuclear factor-κB (NF-κB), and peroxisome proliferator activated receptor (PPAR)γ, which are involved in the activation of immune cells, and are also implicated in various stages of inflammation and resolution, respectively, are impacted by Se status. Available therapies for IBD produce detrimental side effects, resulting in the need for alternative therapies. Here, we review the current understanding of the role of NF-κB and PPARγ in the activation of immune cells during IBD, and how Se and selenoproteins modulate effective resolution of inflammation to be considered as a promising alternative to treat IBD.