Methyl deficient diet aggravates experimental colitis in rats

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.

Role of epigenetic modifications mediated by vitamins and trace elements in inflammatory bowel disease

Graphical abstract [Formula: see text] Numerous environmental factors frequently emerge as primary determinants of inflammatory bowel disease (IBD). Diet is a major component of environmental factors, and the consumption of vitamins (A, B, C and D) and trace elements (calcium, iron, zinc and selenium) exerts an impact on the progression of IBD through epigenetic modifications. Intake of vitamins A, B, C and D, as well as excessive amounts of iron and calcium, can modulate the condition of IBD by regulating the levels of DNA methylation, histone acetylation and miRNA. Zinc and selenium alleviate the progression of IBD by regulating the levels of promoter methylation or histone ubiquitination, respectively. Graphical Abstract was adapted from 'Epigenetic levels (layout)', by BioRender.com. Retrieved from https://app.biorender.com/biorender-templates.

Severity of Menstrual Pain Is Associated with Nutritional Intake and Lifestyle Habits

Recently, the employment rate of women in Japan has steadily increased. Approximately 80% of women experience menstrual pain and premenstrual syndrome (PMS). These symptoms decrease a woman's quality of life and her work productivity, leading to an economic loss. This cross-sectional study of 321 healthy Japanese women aged 20-39 years aimed to clarify the lifestyle-related factors or nutrient intake that might cause menstrual pain. The participants underwent body composition measurements and completed meal survey sheets and lifestyle questionnaires, including menstrual status, exercise, sleep and breakfast consumption. Based on the questionnaire results, participants were divided into two groups according to the severity of menstrual pain, namely, heavy and light. Chi-square and Wilcoxon signed-rank sum tests were used to compare the severity of menstrual pain in the two groups. In the heavy group, the intake of animal proteins, including fish, vitamin D and vitamin B12, was significantly lower (p < 0.05), as was the frequency of breakfast consumption and bathing (p < 0.05). The rate of PMS symptoms was significantly higher in the heavy group (p < 0.05). This study suggests that a lack of animal protein, the accompanying vitamins and fatty acids, and the frequency of breakfast or bathing are associated with the severity of menstrual pain.

Protective role of vitamin B12 on acetic acid induced colitis in rats

Objectives

Inflammatory bowel disease (IBD) is a chronic, relapsing, and remittent inflammatory disease of the gastrointestinal tract. Nutritional deficiency may be instrumental in and attributable to this disease. We examined the effect of VitB12 supplementation on acetic acid (AA)-induced colitis in rats.

Material and Methods

Five minutes after the application of acetic acid to the rats to create a colitis model, VitB12 was administered 1 mg/kg, i.p concentration, then the application continued for three consecutive days. Control groups were included for colitis and VitB12. After 4d, the rats were sacrificed, and colonic tissues were harvested for macroscopic and microscopic examination of colonic damage. TNF-α, IL-1β, IL-6, MDA, GSH and SOD values were measured biochemically.

Results

There was statistically significant macroscopic improvement in damage to the colon tissues (p <0.05). The severity of inflammation reduced in the VitB12 treated rat group compared with the control group, but was not significantly. The levels of TNF-α, IL-1β, MDA, and SOD did not differ between AA control and VitB12 treated AA colitis group. However, the levels of IL-6 and GSH were statistically significant different in rats with AA-induced colitis after VitB12 injection (p <0.05).

Conclusion

Nutritional deficiencies might contribute to the pathogenesis of IBD, and the efficacy of VitB12 supplementation has controversial effects on the intestinal mucosa.

Folate and Vitamin B12 Deficiency Exacerbate Inflammation during Mycobacterium avium paratuberculosis (MAP) Infection

Folate and vitamin B₁₂ deficiency is highly prevalent among Crohn's disease (CD) patients. Furthermore, CD pathology can be mediated by Mycobacterium avium subsp. paratuberculosis (MAP) infection. However, the direct effect of folate (B₉) and cobalamin (B₁₂) deficiency during MAP infection remains uncharacterized. This study investigates how folate and B₁₂ deficiency impedes macrophage apoptosis and exacerbates the inflammation in macrophages infected with MAP isolated from CD patients. Accordingly, we measured folate and B₁₂ in ex vivo plasma samples collected from CD patients with or without MAP infection (N = 35 per group). We also measured the expression of the pro-inflammatory cytokines IL-1β and TNF-α, cellular apoptosis and viability markers, and bacterial viability in MAP-infected macrophages cultured in folate and B₁₂ deficient media. We determined that MAP-positive CD patients have significantly lower plasma folate and B₁₂ in comparison to MAP-negative CD patients [414.48 ± 94.60 pg/mL vs. 512.86 ± 129.12 pg/mL, respectively]. We further show that pro-inflammatory cytokines IL-1β and TNF-α are significantly upregulated during folate and vitamin B₁₂ deprivation following MAP infection by several folds, while supplementation significantly reduces their expression by several folds. Additionally, depletion of folate, B₁₂, and folate/B₁₂ following MAP infection, led to decreased macrophage apoptosis from 1.83 ± 0.40-fold to 1.04 ± 0.08, 0.64 ± 0.12, and 0.45 ± 0.07 in folate-low, B₁₂-low, and folate/B₁₂-low cells, respectively. By contrast, folate and folate/B₁₂ supplementation resulted in 3.38 ± 0.70 and 2.58 ± 0.14-fold increases in infected macrophages. Interestingly, changes in overall macrophage viability were only observed in folate-high, folate/B₁₂-high, and folate/B₁₂-low media, with 0.80 ± 0.05, 0.82 ± 0.02, and 0.91 ± 0.04-fold changes, respectively. Incubation of Caco-2 intestinal epithelial monolayers with supernatant from infected macrophages revealed that folate/B₁₂ deficiency led to increased LDH release independent of oxidative stress. Overall, our results indicate that folate and B₁₂ are key vitamins affecting cell survival and inflammation during MAP infection.

Vitamin–Microbiota Crosstalk in Intestinal Inflammation and Carcinogenesis

Inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC) are common diseases of the digestive system. Vitamin deficiencies and gut microbiota dysbiosis have a close relationship with the risk, development, and progression of IBD and CAC. There is a strong link between vitamins and the gut microbiome. Vitamins are extremely crucial for maintaining a healthy gut microbiota, promoting growth and development, metabolism, and innate immunity. Gut microbiota can not only influence the transport process of vitamins, but also produce vitamins to compensate for insufficient food intake. Emerging evidence suggests that oral vitamin supplementation can reduce inflammation levels and improve disease prognosis. In addition, improving the diet structure and consuming foods rich in vitamins not only help to improve the vitamin deficiency, but also help to reduce the risk of IBD. Fecal microbiota transplantation (FMT) and the application of vitamin-producing probiotics can better assist in the treatment of intestinal diseases. In this review, we discuss the interaction and therapeutic roles of vitamins and gut microbiota in IBD and CAC. We also summarize the methods of treating IBD and CAC by modulating vitamins. This may highlight strategies to target gut-microbiota-dependent alterations in vitamin metabolism in the context of IBD and CAC therapy.

Methyl-Donor Micronutrient for Gestating Sows: Effects on Gut Microbiota and Metabolome in Offspring Piglets

This study aimed to investigate the effects of maternal methyl-donor micronutrient supplementation during gestation on gut microbiota and the fecal metabolic profile in offspring piglets. Forty-three Duroc × Erhualian gilts were assigned to two dietary groups during gestation: control diet (CON) and CON diet supplemented with MET (folic acid, methionine, choline, vitamin B6, and vitamin B12). The body weights of offspring piglets were recorded at birth and weaning. Besides this, fresh fecal samples of offspring piglets were collected at 7, 14, and 21 days. The gut microbiota composition, metabolic profile, and short-chain fatty acid (SCFA) profiles in the fecal samples were determined using 16S rDNA sequencing, liquid chromatography-mass spectrometry metabolomics, and gas chromatography methods, respectively. The results showed that maternal methyl-donor micronutrient supplementation increased the microbiota diversity and uniformity in feces of offspring piglets as indicated by increased Shannon and Simpson indices at 7 days, and greater Simpson, ACE, Chao1 and observed species indices at 21 days. Specifically, at the phylum level, the relative abundance of Firmicutes and the Firmicutes to Bacteroidetes ratio were elevated by maternal treatment. At the genus level, the relative abundance of SCFA-producing Dialister, Megasphaera, and Turicibacter, and lactate-producing Sharpea as well as Akkermansia, Weissella, and Pediococcus were increased in the MET group. The metabolic analyses show that maternal methyl-donor micronutrient addition increased the concentrations of individual and total SCFAs of 21-day piglets and increased metabolism mainly involving amino acids, pyrimidine, and purine biosynthesis. Collectively, maternal methyl-donor micronutrient addition altered gut microbiota and the fecal metabolic profile, resulting in an improved weaning weight of offspring piglets.

Association between serum folate with inflammatory markers, disease clinical activity and serum homocysteine in patients with inflammatory bowel disease. Does folate level have an effect on maintaining clinical remission?

Background:

Folate is an important vitamin with protective effect against some human diseases. The aim of this study was to evaluate the relationship between serum folate levels, inflammatory markers and disease clinical activity in patients with inflammatory bowel disease (IBD).

Methods:

The participants were classified into two groups in which 38 IBD patients and 38 healthy controls were studied. Disease clinical activities were evaluated by means of established score systems. Serum folate, homocysteine and C-reactive protein and ESR were measured. Obtained data were analyzed with proper statistical methods and P- value less than 0.05 was considered as statistical significant.

Results:

The level of serum folate was significantly reduced in IBD patients with active disease compared to patients with clinical remission (p=0.043) and also healthy controls (p=0.008). Moreover, there was a significant inverse correlation between serum folate levels and C-reactive protein in IBD patients (r=-0.563 p=0.001). Conclusion: Serum folate levels is associated with inflammatory markers and disease clinical activity in IBD patients, therefore there is a possibility that disease clinical activity is reduced with adequate folate level. (www.actabiomedica.it)

Methyl-donor supplementation prevents intestinal colonization by Adherent-Invasive E. coli in a mouse model of Crohn's disease

Deficiencies in methyl-donor molecules (folate, B12 vitamin), DNA methylation alteration and high prevalence of Adherent-Invasive Escherichia coli (AIEC) are frequently observed in Crohn’s disease (CD) patients. AIEC bacteria adhere to the enterocytes through abnormally expressed carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) glycoprotein on host cells. This work aims at studying the relationship between methyl-donor molecules and AIEC-induced intestinal inflammatory response. CEABAC10 mice, a mouse model of CD, were fed a control or Methyl-donor Supplemented diet (MS diet). CEACAM6 promoter was hypermethylated in intestinal epithelial cells from mice fed an MS diet, which was associated with a significant decrease in CEACAM6 expression. Transcriptomic analysis revealed increased expression of anti-microbial peptides, increase in HSP70 gene family expression and a decreased expression of inflammatory marker Calprotectin upon MS diet, associated to a lower ability of AIEC bacteria to colonize gut mucosa. We observed in a cohort of CD patients that serum folate concentration was inversely correlated to Crohn’s disease endoscopic index of severity and to fecal inflammatory markers. This study demonstrates that methyl-donor supplementation through the diet induces a specific intestinal micro-environment limiting pathobiont colonization of the gut. Clinicians may wish to consider methyl-donor supplementation for methyl-donor deficient CD patients.

Impact of thermal stress exposure on seminal quality, antioxidant defence system, TNF-α and TIMP-3 in Ossimi ram

Heat stress (HS) occupies huge importance nowadays as it leads to severe economic losses especially in livestock. Preserving sheep against HS is one of the governmental scopes where it represents huge percentage of global ruminant. The present research was conducted to study semen quality, some stress and inflammatory markers in Ossimi rams under both hot and mild climatic conditions. The current study was conducted on selected 46 ram samples divided into two groups during summer and winter. Semen analysis, testosterone (TES), cortisol (COR) and blood glucose (BG) levels, and lipid and protein profiles were done. Concentrations of tumour necrosis factor alpha (TNF-α), tissue inhibitor of metalloproteinase-3 (TIMP-3), nitric oxide (NO), malondialdehyde (MDA) and reduced glutathione (GSH) and specific activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD) were assessed. The results in summer compared to winter revealed significant elevation of total defects and number of dead sperms; however, there was reduction in sperm total motility and concentration and external epididymal tail duct diameter. Histological study of epididymal tail lumen exhibited azoospermia. Further, TES, TIMP-3 and GSH levels were decreased and COR, TNF-α, NO and MDA were raised. Specific activities of GPx and SOD were also declined. Additionally, there was a significant increase in concentrations of BG and lipid profiles except high-density lipoprotein. Our data concluded that there were new insights into TNF-α and TIMP-3 as biomarkers can be used in diagnosis of sheep suffering from HS, but further studies are recommended to do in future work about such aspect.

The deficit in folate and vitamin B12 triggers liver macrovesicular steatosis and inflammation in rats with dextran sodium sulfate-induced colitis

The risks of nonalcoholic steatohepatitis (NASH) and deficiency in vitamin B12 and folate (methyl donor deficiency, MDD) are increased in inflammatory bowel disease (IBD). We investigated the influence of MDD on NASH in rats with DSS-induced colitis. Two-month-old male Wistar rats were subjected to MDD diet and/or ingestion of DSS and compared to control animals. We studied steatosis, inflammation, fibrosis, plasma levels of metabolic markers, cytokines and lipopolysaccharide, and inflammatory pathways in liver. MDD triggered a severe macrovesicular steatosis with inflammation in DSS animals that was not observed in animals subjected to DSS or MDD only. The macrovesicular steatosis was closely correlated to folate, vitamin B12, homocysteine plasma level and liver S-adenosyl methionine/S-adenosyl homocysteine (SAM/SAH) ratio. Liver inflammation was evidenced by activation of nuclear factor kappa B (NFκB) pathway and nuclear translocation of NFκB phospho-p65. MDD worsened the increase of interleukin 1-beta (IL-1β) and abolished the increase of IL10 produced by DSS colitis. It increased monocyte chemoattractant protein 1 (MCP-1). MDD triggers liver macrovesicular steatosis and inflammation through imbalanced expression of IL-1β vs. IL10 and increase of MCP-1 in DSS colitis. Our results suggest evaluating whether IBD patients with MDD and increase of MCP-1 are at higher risk of NASH.

Switching to a Healthy Diet Prevents the Detrimental Effects of Western Diet in a Colitis-Associated Colorectal Cancer Model

Inflammatory bowel disease increases the odds of developing colitis-associated cancer. We hypothesized that Western-style diet (WD) aggravates azoxymethane (AOM)/dextran sulfate sodium salt (DSS)-induced colitis-associated tumorigenesis and that switching to the standard AIN93G diet will ameliorate disease symptoms even after cancer initiation. Female BALB/c mice received either WD (WD group) or standard AIN93G diet (AIN group) for the whole experimental period. After five weeks, the mice received 12.5 mg/kg AOM intraperitoneally, followed by three DSS cycles. In one group of mice, the WD was switched to AIN93G the day before starting the first DSS cycle (WD/AIN group). Feeding the WD during the whole experimental period aggravated colitis symptoms, shortened the colon (p < 0.05), changed microbiota composition and increased tumor promotion. On molecular level, the WD reduced proliferation (p < 0.05) and increased expression of the vitamin D catabolizing enzyme Cyp24a1 (p < 0.001). The switch to the AIN93G diet ameliorated this effect, reflected by longer colons, fewer (p < 0.05) and smaller (p < 0.01) aberrant colonic crypt foci, comparable with the AIN group. Our results show that switching to a healthy diet, even after cancer initiation is able to revert the deleterious effect of the WD and could be an effective preventive strategy to reduce colitis symptoms and prevent tumorigenesis.

Nutritional Control of Stem Cell Division through S-Adenosylmethionine in Drosophila Intestine

The intestine has direct contact with nutritional information. The mechanisms by which particular dietary molecules affect intestinal homeostasis are not fully understood. In this study, we identified S-adenosylmethionine (SAM), a universal methyl donor synthesized from dietary methionine, as a critical molecule that regulates stem cell division in Drosophila midgut. Depletion of either dietary methionine or SAM synthesis reduces division rate of intestinal stem cells. Genetic screening for putative SAM-dependent methyltransferases has identified protein synthesis as a regulator of the stem cells, partially through a unique diphthamide modification on eukaryotic elongation factor 2. In contrast, SAM in nutrient-absorptive enterocytes controls the interleukin-6-like protein Unpaired 3, which is required for rapid division of the stem cells after refeeding. Our study sheds light upon a link between diet and intestinal homeostasis and highlights the key metabolite SAM as a mediator of cell-type-specific starvation response.

Methyl-deficient diet promotes colitis and SIRT1-mediated endoplasmic reticulum stress

BACKGROUND

Methyl donor deficiency (MDD) aggravates experimental colitis in rats and increases endoplasmic reticulum (ER) stress through decreased sirtuin 1 (SIRT1) in neuronal cells and myocardium. ER stress plays a key role in IBD pathogenesis.

AIM

We investigated whether the influence of MDD on colitis resulted from an ER stress response triggered by decreased SIRT1 expression.

DESIGN

The unfolded protein response (UPR), chaperones proteins, heat shock factor protein 1 (HSF1) and SIRT1 were examined in rats with MDD and dextran sulfate sodium (DSS)-induced colitis in a Caco-2 cell model with stable expression of transcobalamin-oleosin (TO) chimera, which impairs cellular availability of vitamin B12, and in IBD. The effects of SIRT1 activation were studied both in vitro and in vivo.

RESULTS

MDD aggravated DSS-induced colitis clinically, endoscopically and histologically. MDD activated ER stress pathways, with increased phosphorylate-PKR-like ER kinase, P-eiF-2α, P-IRE-1α, activating transcription factor (ATF)6, XBP1-S protein and ATF4 mRNA expression levels in rats. This was accompanied by reduced SIRT1 expression level and greater acetylation of HSF1, in relation with a dramatic decrease of chaperones (binding immunoglobulin protein (BIP), heat shock protein (HSP)27 and HSP90). Adding either vitamin B12, S-adenosylmethionine or an SIRT1 activator (SRT1720) reduced the UPR in vitro. In rats, SIRT1 activation by SRT1720 prevented colitis by reducing HSF1 acetylation and increasing expression of BIP, HSP27 and HSP90. Immunohistochemistry showed impaired expression of SIRT1 in the colonic epithelium of patients with IBD.

CONCLUSIONS

SIRT1 is a master regulator of ER stress and severity of experimental colitis in case of MDD. It could deserve further interest as a therapeutic target of IBD.

Management of Ocular Neuropathic Pain With Vitamin B12 Supplements: A Case Report

PURPOSE

To report the case of a 28-year-old patient with persistent bilateral burning pain and foreign body sensation in both eyes for the past 1 year. The patient showed a poor response to 0.05% cyclosporine eye drops and frequent instillations of artificial tears. Ocular examination showed few superficial punctate epithelial defects, well-positioned laser in situ keratomileusis (performed 5 years ago with symptomless recovery) flaps, and clear interfaces bilaterally, with a tear film breakup time of 7 and 8 seconds in the right and left eyes, respectively. The results of Schirmer tests, confocal microscopy, corneal esthesiometry, and meibography were normal for both eyes. The patient was incidentally diagnosed with vitamin B12 deficiency, with a serum vitamin B12 value of 90 pg/mL (reference range, 236-911 pg/mL), during routine laboratory tests. In view of weak correlation between signs and symptoms, a putative diagnosis of ocular neuropathic pain secondary to vitamin B12 deficiency was made.

METHODS

Case report.

RESULTS

The patient was treated with parenteral vitamin B12, and topical therapy was continued without any changes. The patient experienced dramatic improvement with a decrease in symptoms within 3 weeks of administering vitamin B12 supplements and was symptom-free in the absence of any topical medication 6 months after treatment.

CONCLUSIONS

Vitamin B12 deficiency, although common in India, has not been reported to be associated with ocular symptoms, including pain and mimicking those seen in severe dry eye. Vitamin B12 deficiency should be considered in the differential diagnosis of ocular neuropathic pain and dry eye in patients presenting with recalcitrant ocular neuropathic pain.

Diet-Induced Hyperhomocysteinaemia Increases Intestinal Inflammation in an Animal Model of Colitis

BACKGROUND

Hyperhomocysteinaemia [HHcy] is a common phenomenon observed in patients with inflammatory bowel disease [IBD]. Homocysteine is a pro-inflammatory molecule and has been identified as a risk factor for cardiovascular and cerebral diseases. Whether HHcy contributes to the chronic inflammation of the colon in IBD has rarely been explored. The aim of this study was to investigate the effect of HHcy on dextran sulphate sodium [DSS]-induced colitis.

METHODS

Wistar rats were randomly divided into eight groups: [1] Control; [2] HHcy; [3] p38 inhibitor; [4] DSS; [5] HHcy + DSS; [6] HHcy + DSS+p38 inhibitor; [7] HHcy + DSS [21 days]; and [8] HHcy + DSS + folate [21 days]. Colitis was induced by 5% DSS. HHcy was induced by the normal rodent diet containing 1.7% methionine. The mRNA expression of interleukin 17 [IL-17] was detected by qRT-PCR. The protein expressions of IL-17, retinoid-related orphan nuclear receptor-γt [RORγt], p38 MAPK, phosphorylated-p38 MAPK, cytosolic phospolipaseA2 [cPLA2], phosphorylated-cPLA2, and cyclooxygenase 2 [COX2] were detected by immunoblot analysis.

RESULTS

The rats of the HHcy + DSS group had significantly higher myeloperoxidase [MPO] activity, DAI score, and histological score. HHcy significantly increased the plasma concentration, the colonic mRNA, and the protein levels of IL-17. HHcy also activated p38 MAPK and cPLA2, and increased the protein levels of COX2 and RORγt as well as the plasma level of prostaglandin E2 [PGE2]. Folate supplementation down-regulated homocysteine-induced IL-17 and RORγt expressions.

CONCLUSIONS

HHcy aggravated DSS-induced colitis by stimulating IL-17 expression via the p38/cPLA2/COX2/PGE2 signalling pathway. The folate supplementation may represent a novel approach to treating the chronic intestinal inflammation of IBD exacerbated by HHcy.

Diet-induced hypoxia responsive element demethylation increases CEACAM6 expression, favouring Crohn's disease-associated Escherichia coli colonisation

OBJECTIVE

Adherent-invasive Escherichia coli (AIEC) are abnormally predominant on Crohn's disease (CD) ileal mucosa. AIEC strains adhere to enterocytes via interaction between type 1 pili and CEACAM6 receptors abnormally expressed on CD ileal mucosa, leading to gut inflammation. We analysed whether epigenetic mechanisms are involved in the upregulation of CEACAM6 expression in intestinal epithelial cells (IECs).

DESIGN

Methylation of CEACAM6 promoter was analysed using bisulfite sequencing and site-specific methylation by SnapShot. pCpGfree reporter system was used to analyse CEACAM6 promoter activity. Transgenic mice expressing human CEACAM6 fed either standard food or a low-methyl diet (LMD) were orally challenged with 10(9) AIEC LF82. After 3 days, gut-associated AIEC and proinflammatory cytokines were quantified.

RESULTS

Analysis of CEACAM6 gene promoter revealed potentially methylated dinucleotide CpGs within HIF-1-responsive elements (HREs). Methylation levels of CpG within CEACAM6 promoter were inversely correlated with CEACAM6 expression in IEC expressing various levels of CEACAM6. We show the critical role of HRE methylation and transcription factor HIF-1 in the regulation of CEACAM6 gene in IEC. This was confirmed in transgenic mice expressing human CEACAM6 fed a LMD. LMD-dependent HRE demethylation led to abnormal gut expression of CEACAM6, favouring AIEC colonisation and subsequent inflammation.

CONCLUSIONS

HRE hypomethylation in CEACAM6 promoter correlates with high expression in IEC. Our findings suggest that abnormal DNA methylation leading to CEACAM6 increased expression and AIEC-mediated gut inflammation can be related to changes in nutritional habits, such as low intake in methyl donor molecules, leading to abnormal epigenetic marks in mouse model mimicking CD susceptibility.

Linking immunity, epigenetics, and cancer in inflammatory bowel disease

Most of what is known about the pathogenesis of inflammatory bowel disease (IBD) pertains to complex interplay between host genetics, immunity, and environmental factors. Epigenetic modifications play pivotal roles in intestinal immunity and mucosal homeostasis as well as mediating gene-environment interactions. In this article, we provide a historical account of epigenetic research either directly related or pertinent to the pathogenesis and management of IBD. We further collate emerging evidence supporting roles for epigenetic mechanisms in relevant aspects of IBD biology, including deregulated immunity, host-pathogen recognition and mucosal integrity. Finally, we highlight key epigenetic mechanisms that link chronic inflammation to specific IBD comorbidities, including colitis-associated cancer and discuss their potential utility as novel biomarkers or pharmacologic targets in IBD therapy.

Effect of homocysteine on intestinal permeability in rats with experimental colitis, and its mechanism

OBJECTIVE

To investigate the effect of homocysteine (Hcy) on intestinal permeability in rats with TNBS/ethanol-induced colitis and elucidate its mechanism.

METHODS

Sprague-Dawley rats were divided into four groups: normal, normal + Hcy injection, TNBS model, and TNBS model + Hcy injection. Experimental colitis was induced by trinitrobenzene sulfonic acid (TNBS) in 50% ethanol; rats were injected subcutaneously with Hcy from the first day after the induction of experimental colitis on 30 consecutive days. To determine the severity of colitis, the disease activity index (DAI) was evaluated; colon tissues were collected for the detection of the activity of myeloperoxidase (MPO) and the contents of MDA, IL-1β, IL-6, TNF-α, MMP-2, and MMP-9. Intestinal epithelial permeability was assessed with Evans blue (EB) dye. The levels of Hcy in plasma and colon mucosa were measured by high-performance liquid chromatography-fluorescence detection (HPLC-FD).

RESULTS

Compared with the normal group, the DAI scoring and MPO activity, contents of MDA, IL-1β, IL-6, TNF-α, MMP-2, MMP-9 in the colon and EB in the small intestine were significantly increased in the TNBS group (P < 0.01). Compared with the TNBS model group, the DAI scoring, plasma and colonic mucosa Hcy levels, MPO activity and contents of MDA, IL-1β, IL-6, TNF-α, MMP-2, MMP-9 in colon and EB in small intestine were significantly increased in the TNBS-induced colitis rats with simultaneous Hcy injection (P < 0.01).

CONCLUSION

Hcy can increase intestinal permeability and aggravate inflammatory damage in rats with TNBS-induced colitis, the underlying mechanisms of which may be attributed to its effects of promoting the expression of MMP-2 and MMP-9, leading to injury of the intestinal barrier.

DNA methylation in inflammatory bowel disease and beyond

Inflammatory bowel disease (IBD) is a consequence of the complex, dysregulated interplay between genetic predisposition, environmental factors, and microbial composition in the intestine. Despite a great advancement in identifying host-susceptibility genes using genome-wide association studies (GWAS), the majority of IBD cases are still underrepresented. The immediate challenge in post-GWAS era is to identify other causative genetic factors of IBD. DNA methylation has received increasing attention for its mechanistical role in IBD pathogenesis. This stable, yet dynamic DNA modification, can directly affect gene expression that have important implications in IBD development. The alterations in DNA methylation associated with IBD are likely to outset as early as embryogenesis all the way until old-age. In this review, we will discuss the recent advancement in understanding how DNA methylation alterations can contribute to the development of IBD.

Folate and fetal programming: a play in epigenomics?

Folate plays a key role in the interactions between nutrition, fetal programming, and epigenomics. Maternal folate status influences DNA methylation, inheritance of the agouti phenotype, expression of imprinting genes, and the effects of mycotoxin FB1 on heterochromatin assembly in rodent offspring. Deficiency in folate and other methyl donors increases birth defects and produces visceral manifestations of fetal programming, including liver and heart steatosis, through imbalanced methylation and acetylation of PGC1-α and decreased SIRT1 expression, and produces persistent cognitive and learning disabilities through impaired plasticity and hippocampal atrophy. Maternal folate supplementation also produces long-term epigenomic effects in offspring, some beneficial and others negative. Deciphering these mechanisms will help understanding the discordances between experimental models and population studies of folate deficiency and supplementation.

The effects of vitamin B12 and diclofenac and their combination on cold and mechanical allodynia in a neuropathic pain model in rats

The present study was performed to investigate the effects of long-term intraperitoneal (IP) injection of vitamin B12 and diclofenac in separate and combined treatments on cold and mechanical allodynia in a neuropathic pain model in rats. Neuropathic pain was induced by crush injury in right tibial nerve. Acetone spray and von Frey tests were used to obtain cold and mechanical allodynia responses, respectively, on day 11 after nerve crush. Normal saline, vitamin B12 and diclofenac were injected intraperitoneally for 10 consecutive days after surgery. Normal saline treated rats showed cold and mechanical allodynia responses after nerve crush. Vitamin B12 at doses of 50, 100 and 200 µg kg(-1) and diclofenac at a dose of 2 mg kg(-1) produced antiallodynic effects. Antiallodynic effects were not observed when subanalgesic doses of vitamin B12 (25 µg kg(-1)) and diclofenac (0.25 mg kg(-1)) were used together. By increasing the dose of vitamin B12 to an effective dose (100 µg kg(-1)), antiallodynic effects were observed when compared with diclofenac (0.25 mg kg(-1)) alone. The results indicated that vitamin B12 and diclofenac produced neuropathic pain suppressing effects. Moreover, a potentiation effect was observed between vitamin B12 and diclofenac.

Methyl donor deficiency impairs fatty acid oxidation through PGC-1α hypomethylation and decreased ER-α, ERR-α, and HNF-4α in the rat liver

BACKGROUND & AIMS

Folate and cobalamin are methyl donors needed for the synthesis of methionine, which is the precursor of S-adenosylmethionine, the substrate of methylation in epigenetic, and epigenomic pathways. Methyl donor deficiency produces liver steatosis and predisposes to metabolic syndrome. Whether impaired fatty acid oxidation contributes to this steatosis remains unknown.

METHODS

We evaluated the consequences of methyl donor deficient diet in liver of pups from dams subjected to deficiency during gestation and lactation.

RESULTS

The deprived rats had microvesicular steatosis, with increased triglycerides, decreased methionine synthase activity, S-adenosylmethionine, and S-adenosylmethionine/S-adenosylhomocysteine ratio. We observed no change in apoptosis markers, oxidant and reticulum stresses, and carnityl-palmitoyl transferase 1 activity, and a decreased expression of SREBP-1c. Impaired beta-oxidation of fatty acids and carnitine deficit were the predominant changes, with decreased free and total carnitines, increased C14:1/C16 acylcarnitine ratio, decrease of oxidation rate of palmitoyl-CoA and palmitoyl-L-carnitine and decrease of expression of novel organic cation transporter 1, acylCoA-dehydrogenase and trifunctional enzyme subunit alpha and decreased activity of complexes I and II. These changes were related to lower protein expression of ER-α, ERR-α and HNF-4α, and hypomethylation of PGC-1α co-activator that reduced its binding with PPAR-α, ERR-α, and HNF-4α.

CONCLUSIONS

The liver steatosis resulted predominantly from hypomethylation of PGC1-α, decreased binding with its partners and subsequent impaired mitochondrial fatty acid oxidation. This link between methyl donor deficiency and epigenomic deregulations of energy metabolism opens new insights into the pathogenesis of fatty liver disease, in particular, in relation to the fetal programming hypothesis.

Methyl donor deficiency affects small-intestinal differentiation and barrier function in rats

Dietary methyl donors and their genetic determinants are associated with Crohn's disease risk. We investigated whether a methyl-deficient diet (MDD) may affect development and functions of the small intestine in rat pups from dams subjected to the MDD during gestation and lactation. At 1 month before pregnancy, adult females were fed with either a standard food or a diet without vitamin B12, folate and choline. A global wall hypotrophy was observed in the distal small bowel (MDD animals 0·30 mm v. controls 0·58 mm; P< 0·001) with increased crypt apoptosis (3·37 v. 0·4 %; P< 0·001), loss of enterocyte differentiation in the villus and a reduction in intestinal alkaline phosphatase production. Cleaved caspase-3 immunostaining (MDD animals 3·37 % v. controls 0·4 %, P< 0·001) and the Apostain labelling index showed increased crypt apoptosis (3·5 v. 1·4 %; P= 0·018). Decreased proliferation was observed in crypts of the proximal small bowel with a reduced number of minichromosome maintenance 6 (MDD animals 52·83 % v. controls 83·17 %; P= 0·048) and proliferating cell nuclear antigen-positive cells (46·25 v. 59 %; P= 0·05). This lack of enterocyte differentiation in the distal small bowel was associated with an impaired expression of β-catenin and a decreased β-catenin–E-cadherin interaction. The MDD affected the intestinal barrier in the proximal small bowel by decreasing Paneth cell number after immunostaining for lysosyme (MDD animals 8·66 % v. controls 21·66 %) and by reducing goblet cell number and mucus production after immunostaining for mucin-2 (crypts 8·66 v. 15·33 %; villus 7 v. 17 %). The MDD has dual effects on the small intestine by producing dramatic effects on enterocyte differentiation and barrier function in rats.

An endogenously anti-inflammatory role for methylation in mucosal inflammation identified through metabolite profiling

Tissues of the mucosa are lined by an epithelium that provides barrier and transport functions. It is now appreciated that inflammatory responses in inflammatory bowel diseases are accompanied by striking shifts in tissue metabolism. In this paper, we examined global metabolic consequences of mucosal inflammation using both in vitro and in vivo models of disease. Initial analysis of the metabolic signature elicited by inflammation in epithelial models and in colonic tissue isolated from murine colitis demonstrated that levels of specific metabolites associated with cellular methylation reactions are significantly altered by model inflammatory systems. Furthermore, expression of enzymes central to all cellular methylation, S-adenosylmethionine synthetase and S-adenosylhomocysteine hydrolase, are increased in response to inflammation. Subsequent studies showed that DNA methylation is substantially increased during inflammation and that epithelial NF-κB activity is significantly inhibited following treatment with a reversible S-adenosylhomocysteine hydrolase inhibitor, DZ2002. Finally, these studies demonstrated that inhibition of cellular methylation in a murine model of colitis results in disease exacerbation while folate supplementation to promote methylation partially ameliorates the severity of murine colitis. Taken together, these results identify a global change in methylation, which during inflammation, translates to an overall protective role in mucosal epithelia.