Homocysteine, cysteine, and glutathione in human colonic mucosa: elevated levels of homocysteine in patients with inflammatory bowel disease

Hydrogel-forming viscous liquid in response to ROS restores the gut mucosal barrier of colitis mice via regulating oxidative redox homeostasis

The disrupted oxidative redox homeostasis plays a critical role in the progress of ulcerative colitis (UC). Herein, hydrogel-forming viscous liquid (HSD) composed of cysteamine-grafted hyaluronic acid (HS) and superoxide dismutase (SOD) has been designed for UC. When the viscous HSD liquid was infused into colitis colon, SOD would convert the pathological superoxide (O2·-) to hydrogen peroxides (H2O2), which was subsequently scavenged by HS. Accordingly, the sol-gel transition of HSD was initiated by scavenging H2O2, enhancing its adhesion toward colitis colon. H2O2-treated HSD presented the higher storage modulus and stronger adhesion force toward porcine colon than the untreated HSD. Besides, H2O2-treated HSD presented the slower erosion profile in the colitis-mimicking medium (pH 3-5), while its rapid degradation was displayed in physiologic condition (pH7.4). The combination of pH-resistant erosion and ROS-responsive adhesion for HSD rendered it with the specifical retention on the inflamed colonic mucosa of DSS-induced colitis mice. Rectally administrating HSD could effectively hinder the body weight loss, reduce the disease activity index and improve the colonic shorting of DSS-induced colitis mice. Moreover, the pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) were substantially decreased, the colonic epitheliums were well rearranged and the tight junction proteins were greatly recovered after HSD treatment. Besides, HSD also modulated the gut flora, markedly augmenting the abundance of Firmicutes, Barnesiella and Lachnospiraceae. Moreover, HSD treatment could regulate oxidative redox homeostasis via activating Nrf2-HO-1 pathway to reduce ROS and malondialdehyde and upregulate antioxidant enzymes (SOD, GPx and GSH). Collectively, HSD might be a promising therapy for UC treatments. STATEMENT OF SIGNIFICANCE: Herein, a hydrogel-forming viscous liquid (HSD) was designed by cysteamine-grafted hyaluronic acid (HS) and superoxide dismutase (SOD) for UC treatments. When the viscous HSD liquid was infused into a colitis colon, SOD would convert the pathological superoxide to hydrogen peroxides (H2O2), which was subsequently scavenged by HS. Accordingly, the sol-gel transition of HSD was initiated by scavenging H2O2, enhancing its adhesion to the colitis colon. The colonic epitheliums of DSS-induced colitis mice were well rearranged and the tight junction proteins (Zonula-1 and Claudin-5) were greatly recovered after the HSD treatment. Moreover, the HSD treatment could regulate oxidative redox homeostasis via activating the Nrf2-HO-1 pathway to reduce ROS and malondialdehyde and upregulate antioxidant enzymes (SOD, GPx and GSH).

From Gut to Brain: Uncovering Potential Serum Biomarkers Connecting Inflammatory Bowel Diseases to Neurodegenerative Diseases

Inflammatory bowel diseases (IBDs) are characterized by chronic gastrointestinal inflammation due to abnormal immune responses to gut microflora. The gut-brain axis is disrupted in IBDs, leading to neurobiological imbalances and affective symptoms. Systemic inflammation in IBDs affects the brain's inflammatory response system, hormonal axis, and blood-brain barrier integrity, influencing the gut microbiota. This review aims to explore the association between dysregulations in the gut-brain axis, serum biomarkers, and the development of cognitive disorders. Studies suggest a potential association between IBDs and the development of neurodegeneration. The mechanisms include systemic inflammation, nutritional deficiency, GBA dysfunction, and the effect of genetics and comorbidities. The objective is to identify potential correlations and propose future research directions to understand the impact of altered microbiomes and intestinal barrier functions on neurodegeneration. Serum levels of vitamins, inflammatory and neuronal damage biomarkers, and neuronal growth factors have been investigated for their potential to predict the development of neurodegenerative diseases, but current results are inconclusive and require more studies.

Pharmacological Activation of TRPC6 Channel Prevents Colitis Progression

We recently reported that transient receptor potential canonical (TRPC) 6 channel activity contributes to intracellular Zn2+ homeostasis in the heart. Zn2+ has also been implicated in the regulation of intestinal redox and microbial homeostasis. This study aims to investigate the role of TRPC6-mediated Zn2+ influx in the stress resistance of the intestine. The expression profile of TRPC1-C7 mRNAs in the actively inflamed mucosa from inflammatory bowel disease (IBD) patients was analyzed using the GEO database. Systemic TRPC3 knockout (KO) and TRPC6 KO mice were treated with dextran sulfate sodium (DSS) to induce colitis. The Zn2+ concentration and the mRNA expression levels of oxidative/inflammatory markers in colon tissues were quantitatively analyzed, and gut microbiota profiles were compared. TRPC6 mRNA expression level was increased in IBD patients and DSS-treated mouse colon tissues. DSS-treated TRPC6 KO mice, but not TRPC3 KO mice, showed severe weight loss and increased disease activity index compared with DSS-treated WT mice. The mRNA abundances of antioxidant proteins were basically increased in the TRPC6 KO colon, with changes in gut microbiota profiles. Treatment with TRPC6 activator prevented the DSS-induced colitis progression accompanied by increasing Zn2+ concentration. We suggest that TRPC6-mediated Zn2+ influx activity plays a key role in stress resistance against IBD, providing a new strategy for treating colitis.

Limitation of amino acid availability by bacterial populations during enhanced colitis in IBD mouse model

IMPORTANCE

Inflammatory bowel disease is associated with an increase in Enterobacteriaceae and Enterococcus species; however, the specific mechanisms are unclear. Previous research has reported the associations between microbiota and inflammation, here we investigate potential pathways that specific bacteria populations use to drive gut inflammation. Richie et al. show that these bacterial populations utilize an alternate sulfur metabolism and are tolerant of host-derived immune-response products. These metabolic pathways drive host gut inflammation and fuel over colonization of these pathobionts in the dysbiotic colon. Cultured isolates from dysbiotic mice indicated faster growth supplemented with L-cysteine, showing these microbes can utilize essential host nutrients.

Human protozoa infection and dysplasia in ulcerative colitis: a neglected aspect in a prominent disease

The chance of getting colorectal cancer (CRC) is higher in people with chronic ulcerative colitis (UC). The impact of parasitic infections on UC is underappreciated. The purpose of this study was to look into the effect of intestinal protozoal infections on the dysplastic changes generated by UC. The research included 152 adult patients with histologically confirmed UC and 152 healthy controls. Fecal samples were examined for the presence of parasites and fecal calprotectin (FC). The enzyme-linked immunosorbent assay measured serum anti-p53 antibodies (p53Abs) and metallothioneins (MTs). The advanced oxidation protein products (AOPPs) and reduced glutathione (GSH) levels were measured by a spectrophotometric method in all subjects. Serum C-reactive protein (CRP) and IL-6 were also measured. In addition, histopathological and immunohistochemical investigations of intestinal tissue were done. Our results exhibited significant increases in FC and CRP, IL-6, AOPPs, MTs, and p53Abs in ulcerative colitis patients with parasitic infections compared to those without parasites. In contrast, GSH levels showed a significant decrease in the same group compared with other groups. Histopathological and immunohistochemical assessments of intestinal tissue signified severe inflammation and strong expression of PD-L1 in patients with parasitic infections compared to others without parasitic infections. Our research indicated a greater frequency of intestinal protozoa in UC patients with elevated inflammatory and dysplastic biomarker levels. This suggests that these parasites may be involved in the etiology of chronic UC and the associated carcinogenetic process. This is the first report of a link between parasitic infections and dysplastic alterations in UC patients.

Exogenous fetuin-A protects against sepsis-induced myocardial injury by inhibiting oxidative stress and inflammation in mice

Sepsis-induced myocardial injury is a consequence of septicemia and is one of the major causes of death in intensive care units. A serum glycoprotein called fetuin-A is secreted largely by the liver, tongue, placenta, and adipose tissue. Fetuin-A has a variety of biological and pharmacological properties. The anti-inflammatory and antioxidant glycoprotein fetuin-A has shown its efficacy in a number of inflammatory disorders including sepsis. However, its protective role against sepsis-induced myocardial injury remains elusive. The purpose of this work is to explore the role of fetuin-A in mouse models of myocardial injury brought on by cecal ligation and puncture (CLP). CLP significantly induced the myocardial injury assessed in terms of elevated myocardial markers (serum CK-MB, cTnI levels), inflammatory markers (IL-6, TNF-α) in the serum, and oxidative stress markers (increased MDA levels and decreased reduced glutathione) in heart tissue homogenate following 24 h of ligation and puncture. Further, hematoxylin and eosin (H&E) staining showed considerable histological alterations in the myocardial tissue of sepsis-developed mice. Interestingly, fetuin-A pretreatment (50 and 100 mg/kg) for 4 days before the CLP procedure significantly improved the myocardial injury and was evaluated in perspective of a reduction in the CK-MB, cTnI levels, IL-6, and TNF-α in sepsis-developed animals. Fetuin-A pretreatment significantly attenuated the oxidative stress and improved the myocardial morphology in a dose-dependent manner. The present study provides preliminary evidence that fetuin-A exerts protection against sepsis-induced cardiac dysfunction in vivo via suppression of inflammation and oxidative damage.

Serum homocysteine level was elevated in ulcerative colitis and can be applied as diagnostic biomarker

Objective

To investigate the correlation between serum level of homocysteine (Hcy) and ulcerative colitis (UC) and evaluate its diagnostic performance by pooling the open published data.

Methods

The case–control or cohort studies relevant to serum level of Hcy and UC, published in Pubmed, Medline, EMBASE, China Wanfang and CNKI databases, were systematically screened by using the text word of “homocysteine,” “hcy,” “UC,” “inflammatory bowel disease.” The standard mean difference (SMD) was pooled through random effect model. The diagnostic sensitivity, specificity and area under the receiver operating characteristic (AUC) curve of serum Hcy for UC were also calculated.

Results

Eighteen relevant case–control studies were identified by electronic searching the related databases. The pooled results indicated that the serum levels of Hcy were statical different between UC and healthy controls with SMD = 0.95 (95% CI: 0.87–1.04). The serum levels of Hcy were 14.30 ± 3.08 (range: 10.10–21.73) and 10.09 ± 1.57 (range: 6.80–12.47) μmol/L for UC and healthy controls, respectively, of the included 18 studies. Using serum Hcy as biomarker for UC identification, the diagnostic sensitivity, specificity and AUC were 94.44% (95% CI: 72.71–99.86%), 72.22% (46.52–90.31%) and 0.88 (95% CI: 0.77–0.99, P < 0.05), respectively. Significant publication bias was identified in the present work.

Conclusion

Based on the present publications, serum Hcy was elevated in UC cases and can be applied as serological marker for UC diagnosis. However, due to significant publication bias, the diagnostic performance should be further validated by well-designed prospective diagnostic studies.

A novel promising diagnosis model for colorectal advanced adenoma and carcinoma based on the progressive gut microbiota gene biomarkers

BACKGROUND

Colorectal cancer (CRC), a commonly diagnosed cancer often develops slowly from benign polyps called adenoma to carcinoma. Altered gut microbiota is implicated in colorectal carcinogenesis. It is warranted to find non-invasive progressive microbiota biomarkers that can reflect the dynamic changes of the disease. This study aimed to identify and evaluate potential progressive fecal microbiota gene markers for diagnosing advanced adenoma (AA) and CRC.

RESULTS

Metagenome-wide association was performed on fecal samples from different cohorts of 871 subjects (247 CRC, 234 AA, and 390 controls). We characterized the gut microbiome, identified microbiota markers, and further constructed a colorectal neoplasms classifier in 99 CRC, 94 AA, and 62 controls, and validated the results in 185 CRC, 140 AA, and 291 controls from 3 independent cohorts. 21 species and 277 gene markers were identified whose abundance was significantly increased or decreased from normal to AA and CRC. The progressive gene markers were distributed in metabolic pathways including amino acid and sulfur metabolism. A diagnosis model consisting of four effect indexes was constructed based on the markers, the sensitivities of the Adenoma Effect Index 1 for AA, Adenoma Effect Index 2 for high-grade dysplasia (HGD) adenoma were 71.3% and 76.5%, the specificities were 90.5% and 90.3%, respectively. CRC Effect Index 1 for all stages of CRC and CRC Effect Index 2 for stage III-IV CRC to predict CRC yielded an area under the curve (AUC) of 0.839 (95% CI 0.804-0.873) and 0.857 (95% CI 0.793-0.921), respectively. Combining with fecal immunochemical test (FIT) significantly improved the sensitivity of CRC Effect Index 1 and CRC Effect Index 2 to 96.7% and 100%.

CONCLUSIONS

This study reports the successful diagnosis model establishment and cross-region validation for colorectal advanced adenoma and carcinoma based on the progressive gut microbiota gene markers. The results suggested that the novel diagnosis model can significantly improve the diagnostic performance for advanced adenoma.

cRGD peptide incorporated with patchouli alcohol loaded silk fibroin nanoparticles for enhanced targeting of inflammatory sites in colitis

The combination therapy of strengthening inflammation regression and mucosal repair may overcome the "therapeutic ceiling" of ulcerative colitis (UC). However, poor targeting is an outstanding challenge in the preparation of drug delivery systems for UC treatment. Here, we developed anti-inflammatory drug (patchouli alcohol, PA)-loaded nanoparticles (NPs) derived from natural silk fibroin (SF) and subjected to surface functionalization with cyclo RGD peptide (cRGD). Self-assembled SF NPs realized sustained drug release. Meanwhile, cRGD functionalization yielded notably targeted drug delivery to inflamed colon, and thereby enhanced the anti-inflammatory and barrier repair capabilities of NPs. Moreover, cRGD-PASFNs regulated innate immune responses and exerted a potent therapeutic efficacy against acute colitis. Surprisingly, the cRGD-PASFNs also modulated the abnormal level of amino acids which are crucial to the integrity of the intestinal barrier. Additionally, oral delivery of this nanomedicine displayed an excellent safety profile in the mouse model. This study confers confidence for the further development of targeted precision therapy for UC and other inflammatory diseases.

Evidence-based pathogenesis and treatment of ulcerative colitis: A causal role for colonic epithelial hydrogen peroxide

In this comprehensive evidence-based analysis of ulcerative colitis (UC), a causal role is identified for colonic epithelial hydrogen peroxide (H₂O₂) in both the pathogenesis and relapse of this debilitating inflammatory bowel disease. Studies have shown that H₂O₂ production is significantly increased in the non-inflamed colonic epithelium of individuals with UC. H₂O₂ is a powerful neutrophilic chemotactic agent that can diffuse through colonic epithelial cell membranes creating an interstitial chemotactic molecular “trail” that attracts adjacent intravascular neutrophils into the colonic epithelium leading to mucosal inflammation and UC. A novel therapy aimed at removing the inappropriate H₂O₂ mediated chemotactic signal has been highly effective in achieving complete histologic resolution of colitis in patients experiencing refractory disease with at least one (biopsy-proven) histologic remission lasting 14 years to date. The evidence implies that therapeutic intervention to prevent the re-establishment of a pathologic H₂O₂ mediated chemotactic signaling gradient will indefinitely preclude neutrophilic migration into the colonic epithelium constituting a functional cure for this disease. Cumulative data indicate that individuals with UC have normal immune systems and current treatment guidelines calling for the suppression of the immune response based on the belief that UC is caused by an underlying immune dysfunction are not supported by the evidence and may cause serious adverse effects. It is the aim of this paper to present experimental and clinical evidence that identifies H₂O₂ produced by the colonic epithelium as the causal agent in the pathogenesis of UC. A detailed explanation of a novel therapeutic intervention to normalize colonic H₂O₂, its rationale, components, and formulation is also provided.

Histone deacetylase inhibitor givinostat has ameliorative effect in the colitis model

Purpose:

To investigate the effect of givinostat treatment in acetic acid-induced ulcerative colitis model in rats.

Methods:

Thirty male Wistar albino rats were used. Rats were randomly divided into three equal groups, and colitis was induced on 20 rats by rectal administration of %4 solutions of acetic acid. Twenty rats with colitis were randomly divided into two groups. %0.9 NaCl (saline) solution was administered intraperitoneally to the first group of rats (saline group, n=10) at the dose of 1 mL/kg/day. Givinostat was administered intraperitoneally to the second group rats (Givinostat group, n=10) at the dose of 5 mg/kg/day. Samples were collected for biochemical analysis. Colon was removed for histopathological and biochemical examinations.

Results:

Plasma tumor necrosis factor-α (TNF-α), pentraxin-3 (PTX-3), and malondialdehyde levels were significantly decreased in the givinostat group compared to the saline group (p<0.05, p<0.001, and p<0.001 respectively; p<0.001, p<0.001, and p<0.001, respectively). Colon TNF-α and prostaglandin F2 alpha (PGF-2) levels were significantly decreased (p<0.05, and p<0.001, respectively). The givinostat group had a significantly lower histologic score than saline group (p<0.001, and p<0.001, respectively).

Conclusions:

Givinostat, a good protector and regenerator of tissue and an anti-inflammatory agent, may be involved in the treatment of colitis in the future.

Systematic Metabolic Profiling of Mice with Dextran Sulfate Sodium-Induced Colitis

Purpose

Inflammatory bowel diseases (IBD) are a chronic inflammatory disease, which affects almost all tissues in the body. Previous studies mainly focused on breathing, fecal, and urine samples of patients with IBD. However, there is no comprehensive metabolomic analysis of the serum, colon, heart, liver, kidney, cortex, hippocampus, and brown fat tissues. Therefore, the aim of our study is to evaluate the utility metabolomic analysis of target tissues in the pathogenesis of IBD in exploring new biomarkers for early diagnosis and treatment.

Methods

Male Sprague–Dawley rats were randomly allocated to control and DSS-treated groups (n = 7). Dextran sulfate sodium (DSS) was orally administered for 6 weeks. Gas chromatography-mass spectrometry (GC-MS) was used for metabolite determination, multivariate statistical analysis was used to identify metabolites that were differentially expressed in two groups.

Results

Our results showed that 3, 11, 12, 6, 5, 13, 13, and 11 metabolites were differentially expressed between the DSS treatment group and the control group in the serum, colon, heart, liver, kidney, cortex, hippocampus, and brown fat tissues, respectively. The most significant change of metabolites in the study was amino acid (L-alanine, L-glutamic acid, L-phenylalanine, L-proline, L-lysine, L-isoleucine, L-tryptophan, L-norleucine, L-valine, glycine, serine, L-threonine), organic acid (citric acid, 3-hydroxybutyric acid, propanoic acid), glucide (D-arabinose, D-fructose) and purine (9H-purin-6-ol, D-ribose) profiles. Several pathways were affected according to the integrated pathway analysis. These pathways ranged from amino acid metabolism (such as alanine, aspartate, and glutamate metabolism, glutathione metabolism) to purine metabolism (aminoacyl-tRNA biosynthesis).

Conclusion

Using GC-MS-based profiling of metabolite changes, these results may provide a more comprehensive view for IBD and IBD-related diseases and improve the understanding of IBD pathogenesis.

Inflammatory Bowel Disease and Acute Coronary Syndromes: From Pathogenesis to the Fine Line Between Bleeding and Ischemic Risk

Inflammatory bowel disease (IBD) is a pathological condition that first involves the gastrointestinal wall but can also trigger a systemic inflammatory state and thus extraintestinal manifestations. Systemic inflammation is probably secondary to the passage of bacterial products into the bloodstream because of altered intestinal permeability and the consequent release of proinflammatory mediators. Inflammation, through several diverse pathophysiological pathways, determines both a procoagulative state and systemic endothelial dysfunction, which are both deemed to be responsible for venous and arterial thromboembolic adverse events. The management of systemic thrombotic complications is particularly challenging in this category of patients, who also present a high bleeding risk; what is more, both bleeding and thrombotic risks peak during the active phases of the disease. The literature suggests that treating physicians have been, so far, more heavily influenced by concerns about bleeding than by the thrombotic risk. Despite the absence of data provided by large cohorts or randomized studies, the high risk of arterial and venous atherothrombosis in patients with IBD seems unquestionable. Moreover, several reports suggest that when arterial thromboembolism involves the coronary vessels, causing acute coronary syndromes, ischemic complications from antithrombotic drug undertreatment are frequent and severe. This review aims to shed light on the tricky balance between the ischemic and hemorrhagic risks of patients with IBD and to highlight how difficult it is for clinicians to define a tailored therapy based on a case-by-case, careful, and unprejudiced clinical evaluation.

Hyperhomocysteinemia: Clinical Insights

Homocysteine (Hcy) is a sulfhydryl-containing amino acid, and intermediate metabolite formed in metabolising methionine (Met) to cysteine (Cys); defective Met metabolism can increase Hcy. The effect of hyperhomocysteinemia (HHcy) on human health, is well described and associated with multiple clinical conditions. HHcy is considered to be an independent risk factor for common cardiovascular and central nervous disorders, where its role in folate metabolism and choline catabolism is fundamental in many metabolic pathways. HHcy induces inflammatory responses via increasing the pro-inflammatory cytokines and downregulation of anti-inflammatory cytokines which lead to Hcy-induced cell apoptosis. Conflicting evidence indicates that the development of the homocysteine-associated cerebrovascular disease may be prevented by the maintenance of normal Hcy levels. In this review, we discuss common conditions associated with HHcy and biochemical diagnostic workup that may help in reaching diagnosis at early stages. Furthermore, future systematic studies need to prove the exact pathophysiological mechanism of HHcy at the cellular level and the effect of Hcy lowering agents on disease courses.

Hydrogen peroxide and disease: towards a unified system of pathogenesis and therapeutics

Although the immune response has a prominent role in the pathophysiology of ulcerative colitis, sepsis, and systemic lupus erythematosus, a primary immune causation has not been established to explain the pathogenesis of these diseases. However, studies have reported significantly elevated levels of colonic epithelial hydrogen peroxide (a known colitic agent) in ulcerative colitis prior to the appearance of colitis. And patients with sepsis are reported to have toxic levels of blood hydrogen peroxide, whose pathologic effects mirror the laboratory and clinical abnormalities observed in sepsis. More recently, evidence supports a causal role for cellular hydrogen peroxide (a potent apoptotic agent) in the enhanced apoptosis believed to be the driving force behind auto-antigenic exposure and chronic immune activation in systemic lupus erythematosus. The different biological properties of hydrogen peroxide exert distinct pathologic effects depending on the site of accumulation within the body resulting in a unique disease patho-phenotype. On a cellular level, the build-up of hydrogen peroxide triggers apoptosis resulting in systemic lupus erythematosus, on a tissue level (colonic epithelium) excess hydrogen peroxide leads to inflammation and ulcerative colitis, and on a systemic level the pathologic effects of toxic concentrations of blood hydrogen peroxide result in bioenergetic failure and microangiopathic dysfunction leading to multiple organ failure and circulatory shock, characteristic of advanced sepsis. The aim of this paper is to provide a unified evidence-based common causal role for hydrogen peroxide in the pathogenesis of ulcerative colitis, sepsis, and systemic lupus erythematosus. Based on this new theory of pathogenesis, a novel evidence-based treatment of sepsis is also discussed.

A novel highly sensitive fluorescent probe for bioimaging biothiols and its applications in distinguishing cancer cells from normal cells

In recent years, targeting drugs made by physical loading or chemical bonding of drugs on small molecular carriers have shown a very wide application prospect in the field of tumor and cancer treatment. How to achieve the release of drugs in cancer cells has become the core of this research. One of the most important bases for drug localization is to use the difference of small molecular biothiol concentration between cancer cells and normal cells. Details of the changes of biothiol levels in the growth and reproduction of cancer cells are still poorly understood, and the main reason is the lack of sensitive real-time imaging tools for biothiols in cancer cells. In this work, we reasonably designed and synthesized the combination of 4-hydroxy-1,8-naphthalimide and NBD-Cl as a concise fluorescent probe HN-NBD for imaging biothiols in live cells and zebrafish. In addition, due to the advantages of HN-NBD design, it is sufficiently sensitive to biothiols, and further imaging can distinguish cancer cells from normal cells. Probe HN-NBD would be of great significance to biomedical researchers for the study of biothiol-related diseases, the screening of new anticancer drugs, and the early diagnosis and treatment of cancers.

A Cross-Sectional Study on Malnutrition in Inflammatory Bowel Disease: Is There a Difference Based on Pediatric or Adult Age Grouping?

BACKGROUND

Malnutrition, commonly observed in inflammatory bowel disease (IBD), is associated with increased morbidity and mortality and is attributed to multiple causes. The added energy costs of growth in the child and adolescent with IBD are an additional risk factor.

METHODS

The aim of the study was to perform a cross-sectional comparison of nutritional parameters in IBD between pediatric and adult cases.

RESULTS

We found that prevalence of undernutrition (low body mass index) and hypoalbuminemia was not different in pediatric, compared with adult patients. Anemia and iron deficiency were more often observed in pediatric subjects, compared with adults (59.1% vs 36.9%, respectively, P < 0.0001; and 37.9% vs 25.3%, P < 0.002). Vitamin B12 deficiency was significantly less common in the pediatric than in the adult group (5.4% vs 19.4%, P < 0.0001). Elevated C-reactive protein was more frequent in pediatric compared with adult cases (49.8% vs 38.4%, P < 0.01).

CONCLUSIONS

Patients with active Crohn's disease were more likely to be undernourished in both pediatric and adult populations. In both groups, predicators of undernutrition included low albumin levels (odds ratio [OR], 2.53; P < 0.006) and active disease (OR, 1.99; P < 0.03). Our results call for close surveillance of nutritional status for IBD patients, regardless of age.

Severe Crohn's Disease Manifestations in a Child with Cystathionine β-Synthase Deficiency

Inflammatory bowel diseases (IBDs) are idiopathic autoimmune diseases that are characterized by inflammation of both the small and large intestine. Although IBD is common in the general population, the pathophysiology remains ambiguous. Clear understanding of IBD pathophysiology would be a major step toward curative treatment in the future. Hyperhomocysteinemia has been associated with multiple autoimmune diseases including IBD, but homocystinuria has not been associated with IBD before. We report a 9-year-old girl with Crohn’s disease and homocystinuria. Her gastrointestinal symptoms improved significantly upon classical homocystinuria treatment, and her last colonoscopy showed a pronounced remission. This case supports the inflammatory role of homocysteine in the gastrointestinal tract and the association between hyperhomocysteinemia and IBD manifestations.

Comprehensive genetic study of fatty acids helps explain the role of noncoding inflammatory bowel disease associated SNPs and fatty acid metabolism in disease pathogenesis

Fatty acids and their derivatives play an important role in inflammation. Diet and genetics influence fatty acid profiles. Abnormalities of fatty acid profiles have been observed in inflammatory bowel diseases (IBD), a group of complex diseases defined by chronic gastrointestinal inflammation. IBD associated fatty acid profile abnormalities were observed independently of nutritional status or disease activity, suggesting a common genetic background. However, no study so far has attempted to look for overlap between IBD loci and fatty acid associated loci or investigate the genetics of fatty acid profiles in IBD. To this end, we conducted a comprehensive genetic study of fatty acid profiles in IBD using iCHIP, a custom microarray platform designed for deep sequencing of immune-mediated disease associated loci. This study identifies 10 loci associated with fatty acid profiles in IBD. The most significant associations were a locus near CBS (p = 7.62 × 10^-8) and a locus in LRRK2 (p = 1.4 × 10^-7). Of note, this study replicates the FADS gene cluster locus, previously associated with both fatty acid profiles and IBD pathogenesis. Furthermore, we identify 18 carbon chain trans-fatty acids (p = 1.12 × 10^-3), total trans-fatty acids (p = 4.49 × 10^-3), palmitic acid (p = 5.85 × 10^-3) and arachidonic acid (p = 8.58 × 10^-3) as significantly associated with IBD pathogenesis.

Different pathways involved in the stimulatory effects of homocysteine on rat duodenal smooth muscle

Recent studies have confirmed that hyperhomocysteinemia is associated with gastrointestinal diseases; however, the direct effect of homocysteine on gastrointestinal reactivity still remains unknown. The aim of this study was to demonstrate how homocysteine may affect nitric oxide mediated duodenal relaxation and whether cholinergic receptors and K+ channels take part in stimulating motility, as well as to explore whether oxidative stress is associated with homocysteine-mediated effects. Experiments were carried out on male rats, body mass 250-300 g. Two groups of animals were treated by i.p. application of saline and D,L-Hcy (0.6 μmol/g bm). After 2h of incubation, the duodenal segments were prepared for biochemical analysis and contractile response measurements in an organ bath with Tyrode’s solution. Effects of TEA (10 mmol/L) and L-NAME (30 μmol/L) on duodenal contractility in the presence of D,L-Hcy (0.6 μmol/g bm) were investigated. Elevated homocysteine levels seem to be of crucial importance for the deterioration of contractility through nitric oxide mediated relaxation, and, in part, by activation of K+ channels. Hcy showed direct promuscarinic effects, since 30 min pretreatment of rat duodenum significantly enhanced the contractile effect of increasing concentrations of ACh (10−9-10−2 mol/L). Catalase activity, superoxide dismutase, glutathione peroxidase and the total antioxidant system were reduced while the thiobarbituric acid-reactive substances level was elevated. Our data showed a consistent profile of gastrointestinal injury elicited by sulfur-containing amino acid-homocysteine. This could contribute to explain, at least in part, the mechanisms involved in human gastrointestinal diseases associated to hyperhomocysteinemia.

Roles of Dietary Amino Acids and Their Metabolites in Pathogenesis of Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD) is a kind of chronic inflammation, which has increasing incidence and prevalence in recent years. IBD mainly divides into Crohn's disease (CD) and ulcerative colitis (UC). It is hard to cure IBD completely, and novel therapies are urgently needed. Amino acids (AAs) and their metabolites are regarded as important nutrients for humans and animals and also play an important role in IBD amelioration. In the present study, the potential protective effects of AAs and their metabolites on IBD had been summarized with the objective to provide insights into IBD moderating using dietary AAs and their metabolites as a potential adjuvant therapy.

The Effects of Subchronic Methionine Overload Administered Alone or Simultaneously with L-cysteine or N-acetyl-L-cysteine on Body Weight, Homocysteine Levels and Biochemical Parameters in the Blood of Male Wistar Rats

Hyperhomocysteinemia (HHC), both basal and after methionine load, may occur due to genetic disorders or deficiencies of nutrients that affect the remethylation or trans-sulphuration pathways during methionine metabolism. HHC is involved in the pathogenesis of many illnesses as a result of its prooxidative effect and its impairment of antioxidative protection. The aim was to examine the effects of subchronic methionine overload on the body weight and standard biochemical parameters in rat serum and to examine whether simultaneous subchronic intraperotoneal administration of methionine alone or together with L-cysteine or N-acetyl-cysteine resulted in a change in the body weight and biochemical parameters in the rat serum. The research was conducted during a three-week period (male Wistar albino rats, n=36, body weight of approximately 160 g, age of 15-20 days), and the animals were divided into a control group and three experimental groups of 8-10 animals each: a) control group (0.9% sodium chloride 0.1-0.2 ml/day); b) methionine (0.8 mmol/kg/bw/day) (MET group); c) methionine (0.8 mmol/kg/bw/day) + L-cysteine (7 mg/kg/bw/day) (L-cys+MET group); and d) methionine (0.8 mmol/kg/bw/day) + N-acetyl-L-cysteine (50 mg/kg/bw/day) (NAC+MET group). In addition to the body weight monitoring, the levels of total homocysteine and the standard biochemical parameters in blood samples (plasma or serum) were determined. The results indicated that monitoring the homocysteine levels and standard biochemical parameters in blood could be used for analysis and could provide an excellent guideline for distinguishing between toxic and non-toxic doses of methionine intake, which may be meaningful for clinical applications.

Cardiovascular complications in inflammatory bowel disease

Over the past years, a growing number of studies have indicated that patients suffering from inflammatory bowel disease (IBD) have an increased risk of developing cardiovascular disease. Both are chronic inflammatory diseases and share certain pathophysiological mechanisms that may influence each other. High levels of cytokines, C-reactive protein (CRP), and homocysteine in IBD patients may lead to endothelial dysfunction, an early sign of atherosclerosis. IBD patients, in general, do not show the typical risk factors for cardiovascular disease but changes in lipid profiles similar to the ones seen in cardiovascular events have been reported recently. Higher levels of coagulation factors frequently occur in IBD which may predispose to arterial thromboembolic events. Finally, the gut itself may have an impact on atherogenesis during IBD through its microbiota. Microbial products are released from the inflamed mucosa into the circulation through a leaky barrier. The induced rise in proinflammatory cytokines could contribute to endothelial damage, artherosclerosis and cardiovascular events. Although large retrospective studies favor a link between IBD and cardiovascular diseases, the mechanisms behind still remain to be determined.

Cardiovascular complications in inflammatory bowel disease

Over the past years, a growing number of studies have indicated that patients suffering from inflammatory bowel disease (IBD) have an increased risk of developing cardiovascular disease. Both are chronic inflammatory diseases and share certain pathophysiological mechanisms that may influence each other. High levels of cytokines, C-reactive protein (CRP), and homocysteine in IBD patients may lead to endothelial dysfunction, an early sign of atherosclerosis. IBD patients, in general, do not show the typical risk factors for cardiovascular disease but changes in lipid profiles similar to the ones seen in cardiovascular events have been reported recently. Higher levels of coagulation factors frequently occur in IBD which may predispose to arterial thromboembolic events. Finally, the gut itself may have an impact on atherogenesis during IBD through its microbiota. Microbial products are released from the inflamed mucosa into the circulation through a leaky barrier. The induced rise in proinflammatory cytokines could contribute to endothelial damage, artherosclerosis and cardiovascular events. Although large retrospective studies favor a link between IBD and cardiovascular diseases, the mechanisms behind still remain to be determined.

A simple excited-state intramolecular proton transfer probe based on a new strategy of thiol–azide reaction for the selective sensing of cysteine and glutathione

A simple azido-substituted fluorescent sensorAHBObased on the mechanism of nucleophilic substitution–rearrangement reactions showed selective turn-on response to cysteine (Cys) and glutathione (GSH).

Novel pyrazoline-based fluorescent probe for detecting glutathione and its application in cells

A novel compound, 2-(1,5-diphenyl-4,5-dihydro-1H-pyrazol-3-yl)phenyl acrylate (probe L), was designed and synthesized as a highly sensitive and selective fluorescent probe for recognizing and detecting glutathione among cysteine, homocysteine and other amino acids. The structures of related compounds were characterized using IR, NMR and HRMS spectroscopy analysis. The probe is a non-fluorescent compound. On being mixed with glutathione in buffered EtOH:PBS=3:7 solution at pH 7.4, the probe exhibited the blue emission of the pyrazoline at 474 nm and a 83-fold enhancement in fluorescence intensity. This probe is very sensitive and displayed a linear fluorescence off-on response to glutathione with fluorometric detection limit of 8.2 × 10(-8)M. The emission of the probe is pH independent in the physiological pH range. Live-cell imaging of HeLa cells confirmed the cell permeability of the probe and its ability to selectively discriminate GSH from Cys and Hcy in cells. The toxicity of the probe was low in cultured HeLa cells.

Oxidative stress in ulcerative colitis: an old concept but a new concern

Ulcerative colitis is an idiopathic, chronic and relapsing inflammatory bowel disease, which elicits the risk of colorectal cancer, the third most common malignancy in humans. It has been known for a long time that oxidative stress is a major pathogenic factor in the inflamed tissue that can pave the way towards DNA damage and carcinogenesis. However, the DNA damage produced due to oxidative stress in the inflamed tissue is not limited to the local site but extends globally, thereby augmenting the risk of global carcinogenesis. Targeting oxidative stress may provide an exciting avenue to combat inflammation-associated local as well as global DNA damage and the subsequent carcinogenesis. The present review portrays the role of oxidative stress in the pathogenesis of ulcerative colitis and the associated local as well as global DNA damage, which may lead to carcinogenesis.

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.

A fluorescein-based probe with high selectivity to cysteine over homocysteine and glutathione

A fluorescent probe based on fluorescein displays excellent selectivity and sensitivity for cysteine and its application for bio-imaging is described.

Methylenetetrahydrofolate reductase C677T gene polymorphism and colorectal cancer risk: A case-control study

We designed a case-control study to determine the plasma homocysteine (Hcy) level and evaluate the potential role of the methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism in colorectal cancer (CRC). Total Hcy was quantified using the fluorescence polarization immunoassay (FPIA) on the IMx analyzer. Genomic DNA was analyzed by the real-time polymerase chain reaction (RT-PCR). The plasma levels of Hcy in the CRC group (12.63±3.11 μmol/l) were significantly higher compared with those in the control group (10.87±2.42 μmol/l; P<0.05). The frequency of the MTHFR 677TT genotype in CRC patients was markedly high. The MTHFR 677TT genotype was significantly correlated with an increased risk of CRC (odds ratio, 1.671; 95% confidence interval, 1.094-2.553; P=0.018). This study suggests that the MTHFR C677T polymorphism indicates susceptibility to CRC and is correlated with CRC pathogenesis, suggesting that the homozygous variant MTHFR C677T polymorphism is a candidate risk factor for CRC.

Quantitative metabolomic profiling of serum, plasma, and urine by (1)H NMR spectroscopy discriminates between patients with inflammatory bowel disease and healthy individuals

Serologic biomarkers for inflammatory bowel disease (IBD) have yielded variable differentiating ability. Quantitative analysis of a large number of metabolites is a promising method to detect IBD biomarkers. Human subjects with active Crohn’s disease (CD) and active ulcerative colitis (UC) were identified, and serum, plasma, and urine specimens were obtained. We characterized 44 serum, 37 plasma, and 71 urine metabolites by use of ¹H NMR spectroscopy and “targeted analysis” to differentiate between diseased and non-diseased individuals, as well as between the CD and UC cohorts. We used multiblock principal component analysis and hierarchical OPLS-DA for comparing several blocks derived from the same “objects” (e.g., subject) to examine differences in metabolites. In serum and plasma of IBD patients, methanol, mannose, formate, 3-methyl-2-oxovalerate, and amino acids such as isoleucine were the metabolites most prominently increased, whereas in urine, maximal increases were observed for mannitol, allantoin, xylose, and carnitine. Both serum and plasma of UC and CD patients showed significant decreases in urea and citrate, whereas in urine, decreases were observed, among others, for betaine and hippurate. Quantitative metabolomic profiling of serum, plasma, and urine discriminates between healthy and IBD subjects. However, our results show that the metabolic differences between the CD and UC cohorts are less pronounced.

Methyl deficient diet aggravates experimental colitis in rats

Inflammatory bowel diseases (IBD) result from complex interactions between environmental and genetic factors. Low blood levels of vitamin B12 and folate and genetic variants of related target enzymes are associated with IBD risk, in population studies. To investigate the underlying mechanisms, we evaluated the effects of a methyl-deficient diet (MDD, folate, vitamin B12 and choline) in an experimental model of colitis induced by dextran sodium sulphate (DSS), in rat pups from dams subjected to the MDD during gestation and lactation. Four groups were considered (n= 12–16 per group): C DSS⁻ (control/DSS⁻), D DSS⁻ (deficient/DSS⁻), C DSS⁺ (control/DSS⁺) and D DSS⁺ (deficient/DSS⁺). Changes in apoptosis, oxidant stress and pro-inflammatory pathways were studied within colonic mucosa. In rat pups, the MDD produced a decreased plasma concentration of vitamin B12 and folate and an increased homocysteine (7.8 ± 0.9 versus 22.6 ± 1.2 μmol/l, P < 0.001). The DSS-induced colitis was dramatically more severe in the D DSS⁺ group compared with each other group, with no change in superoxide dismutase and glutathione peroxidase activity, but decreased expression of caspase-3 and Bax, and increased Bcl-2 levels. The mRNA levels of tumour necrosis factor (TNF)-α and protein levels of p38, cytosolic phospolipase A2 and cyclooxygenase 2 were significantly increased in the D DSS⁺ pups and were accompanied by a decrease in the protein level of tissue inhibitor of metalloproteinases (TIMP)3, a negative regulator of TNF-α. MDD may cause an overexpression of pro-inflammatory pathways, indicating an aggravating effect of folate and/or vitamin B12 deficiency in experimental IBD. These findings suggest paying attention to vitamin B12 and folate deficits, frequently reported in IBD patients.

Meta-analysis: hyperhomocysteinaemia in inflammatory bowel diseases

BACKGROUND

The magnitude of association between homocysteine metabolism and inflammatory bowel diseases (IBD) remains unknown, whereas the association between hyperhomocysteinaemia and thrombosis remains controversial in IBD.

AIM

To conduct a systematic review and meta-analysis to examine these issues.

METHODS

The literature search was conducted using MEDLINE database and international conference abstracts from January 1966 to April 2011 and included all studies that evaluated plasma homocysteine level in IBD.

RESULTS

Twenty-eight studies evaluated the plasma homocysteine level and/or hyperhomocysteinaemia risk in IBD patients. Five studies assessed the association of hyperhomocysteinaemia with thrombosis. The mean plasma homocysteine level was significantly higher in IBD patients when compared with controls (weighted mean difference (WMD)=3.75 μmol/L; 95% CI, 2.23-5.26 μmol/L; P<0.0001; reference ranges for plasma homocysteine level: 5-12 μmol/L). The mean plasma homocysteine level did not differ between ulcerative colitis (UC) and Crohn's disease (CD) (WMD=0.41 μmol/L; 95% CI, -2.45 to 3.06 μmol/L; P=0.76). The risk of hyperhomocysteinaemia was significantly higher in IBD patients when compared with controls [odds ratio (OR)=4.65; 95% CI, 3.04-7.09; P<0.0001]. The risk of hyperhomocysteinaemia was not higher among IBD patients who experienced thromboembolic complications (OR=1.97; 95% CI, 0.83-4.67; P=0.12). Plasma folate level was inversely correlated with IBD risk associated with MTHFR C677T polymorphism (P=0.006).

CONCLUSIONS

The risk of hyperhomocysteinaemia is significantly higher in IBD patients when compared with controls. The risk assessment of hyperhomocysteinaemia-related thrombosis in IBD requires further investigation. Deficient folate status is associated with a higher impact of MTHFR C677T polymorphism on IBD risk.

B-vitamin deficiency is protective against DSS-induced colitis in mice

Vitamin deficiencies are common in patients with inflammatory bowel disease (IBD). Homocysteine (Hcys) is a thrombogenic amino acid produced from methionine (Met), and its increase in patients with IBD indicates a disruption of Met metabolism; however, the role of Hcys and Met metabolism in IBD is not well understood. We hypothesized that disrupted Met metabolism from a B-vitamin-deficient diet would exacerbate experimental colitis. Mice were fed a B(6)-B(12)-deficient or control diet for 2 wk and then treated with dextran sodium sulfate (DSS) to induce colitis. We monitored disease activity during DSS treatment and collected plasma and tissue for analysis of inflammatory tissue injury and Met metabolites. We also quantified Met cycle activity by measurements of in vivo Met kinetics using [1-(13)C-methyl-(2)H(3)]methionine infusion in similarly treated mice. Unexpectedly, we found that mice given the B-vitamin-deficient diet had improved clinical outcomes, including increased survival, weight maintenance, and reduced disease scores. We also found lower histological disease activity and proinflammatory gene expression (TNF-α and inducible nitric oxide synthase) in the colon in deficient-diet mice. Metabolomic analysis showed evidence that these effects were associated with deficient B(6), as markers of B(12) function were only mildly altered. In vivo methionine kinetics corroborated these results, showing that the deficient diet suppressed transsulfuration but increased remethylation. Our findings suggest that disrupted Met metabolism attributable to B(6) deficiency reduces the inflammatory response and disease activity in DSS-challenged mice. These results warrant further human clinical studies to determine whether B(6) deficiency and elevated Hcys in patients with IBD contribute to disease pathobiology.

p53 antibodies, metallothioneins, and oxidative stress markers in chronic ulcerative colitis with dysplasia

AIM: To investigate the role of p53 antibodies (p53Abs), metallothioneins (MTs) and oxidative stress markers in the early detection of dysplasia in chronic ulcerative colitis (UC).

METHODS: The study included 30 UC patients, 15 without dysplasia (group II) and 15 with dysplasia (group III), in addition to 15 healthy volunteers (group I, control subjects). The enzyme-linked immunosorbent assay technique was used to measure serum p53Abs and MTs, while advanced oxidation protein products (AOPPs), and reduced glutathione (GSH) levels were measured by spectrophotometric method in all subjects.

RESULTS: In group II and group III compared to group I, there were significant increases in serum levels of AOPPs (145.94 ± 29.86 μmol/L and 192.21 ± 46.71 μmol/L vs 128.95 ± 3.06 μmol/L, P < 0.002 and P < 0.001, respectively), MTs (8.18 ± 0.35 μg/mL and 9.20 ± 0.58 μg/mL vs 6.12 ± 0.25 μg/mL, P < 0.05 and P < 0.05, respectively), and p53Abs (20.19 ± 3.20 U/mL and 34.66 ± 1.34 U/mL vs 9.42 ± 1.64 U/mL, P < 0.001 and P < 0.001, respectively). There were significantly higher levels of AOPPs (P < 0.05) and p53Abs (P < 0.001) in UC patients with dysplasia compared to those without dysplasia, while MTs showed no significant difference between the 2 groups (P > 0.096). In contrast, GSH levels showed a significant decrease in both patients’ groups (1.87 ± 0.02 μmol/mL and 1.37 ± 0.09 μmol/mL vs 2.49 ± 0.10 μmol/mL, P < 0.05 and P < 0.05 in groups II and III, respectively) compared with group I, and the levels were significantly lower in group III than group II (P < 0.05). There was a positive correlation between AOPPs and both MTs (r = 0.678, P < 0.001) and p53Abs (r = 0.547, P < 0.001), and also between p53Abs and MTs (r = 0.739, P < 0.001). There was a negative correlation between AOPPs and GSH (r = -0.385, P < 0.001), and also between GSH and both MTs (r = -0.662, P < 0.001) and p53Abs (r = -0.923, P < 0.001).

CONCLUSION: Oxidative stress and oxidative cellular damage play an important role in the pathogenesis of chronic UC and the associated carcinogenetic process. p53Abs levels could help in early detection of dysplasia in these conditions.

MTHFR, MTR, and MTRR polymorphisms in relation to p16INK4A hypermethylation in mucosa of patients with colorectal cancer

We recently analyzed the hypermethylation status of the p16INK4a (p16) gene promoter in normal-appearing mucosa obtained from patients with colorectal cancer. Hypermethylation of p16 was associated with reduced survival of these patients. In the present study, germ line polymorphisms in the folate- and methyl-associated genes, methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR) and methionine synthase reductase (MTRR), were analyzed in the same patient cohort to find a possible link between these genetic variants and p16 hypermethylation. Genomic DNA was extracted from blood of patients (n = 181) and controls (n = 300). Genotype analyses were run on an ABI PRISM(®) 7900HT sequence-detection system (Applied Biosystems), using real-time polymerase chain reaction and TaqMan chemistry. The results showed that the genotype distributions of the patient and control groups were similar. No significant differences in cancer-specific or disease-free survival of stage I-III patients according to polymorphic variants were detected, nor were any differences in cancer-specific or disease-free survival detected when patients were subgrouped according to the MTHFR or MTR genotype groups and dichotomized by p16 hypermethylation status in mucosa. However, patients with the MTRR 66 AA/AG genotypes were found to have a significantly worse cancer-specific survival when the mucosa were positive, compared with negative, for p16 hypermethylation (hazard ratio 2.7; 95% confidence interval 1.2-6.4; P = 0.023). In contrast, there was no difference in survival among patients with the MTRR 66 GG genotype stratified by p16 hypermethylation status. These results indicate a relationship between genetic germ-line variants of the MTRR gene and p16 hypermethylation in mucosa, which may affect the clinical outcome of patients with colorectal cancer.

MTHFR, MTR, and MTRR polymorphisms in relation to p16INK4A hypermethylation in mucosa of patients with colorectal cancer

We recently analyzed the hypermethylation status of the p16INK4a (p16) gene promoter in normal-appearing mucosa obtained from patients with colorectal cancer. Hypermethylation of p16 was associated with reduced survival of these patients. In the present study, germ line polymorphisms in the folate- and methyl-associated genes, methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR) and methionine synthase reductase (MTRR), were analyzed in the same patient cohort to find a possible link between these genetic variants and p16 hypermethylation. Genomic DNA was extracted from blood of patients (n = 181) and controls (n = 300). Genotype analyses were run on an ABI PRISM(®) 7900HT sequence-detection system (Applied Biosystems), using real-time polymerase chain reaction and TaqMan chemistry. The results showed that the genotype distributions of the patient and control groups were similar. No significant differences in cancer-specific or disease-free survival of stage I-III patients according to polymorphic variants were detected, nor were any differences in cancer-specific or disease-free survival detected when patients were subgrouped according to the MTHFR or MTR genotype groups and dichotomized by p16 hypermethylation status in mucosa. However, patients with the MTRR 66 AA/AG genotypes were found to have a significantly worse cancer-specific survival when the mucosa were positive, compared with negative, for p16 hypermethylation (hazard ratio 2.7; 95% confidence interval 1.2-6.4; P = 0.023). In contrast, there was no difference in survival among patients with the MTRR 66 GG genotype stratified by p16 hypermethylation status. These results indicate a relationship between genetic germ-line variants of the MTRR gene and p16 hypermethylation in mucosa, which may affect the clinical outcome of patients with colorectal cancer.

Recurrent deep vein thrombosis despite warfarin therapy in a patient with Crohn's disease

Patients with inflammatory bowel disease (IBD) are known to have an increased propensity for thromboembolic events. Like any patient with a high risk of event recurrence, most of these patients can be managed successfully with long-term warfarin therapy. We present the case of a 66-year-old woman with Crohn's disease who, despite careful attention to the management of her international normalized ratio, developed a new deep vein thrombosis and required inferior vena cava filter placement in addition to ongoing warfarin therapy to prevent recurrent pulmonary emboli. This report serves as a reminder to physicians to have a low threshold for diagnosing thromboembolic events in patients with IBD, even if they are presumed to be adequately anticoagulated. Known and theoretical contributing factors to this increased clotting tendency are also reviewed.

Increased levels of homocysteine in patients with ulcerative colitis

AIM: To investigate serum levels of homocysteine (Hcys) and the risk that altered levels carry for thrombosis development in ulcerative colitis (UC) patients.

METHODS: 55 UC patients and 45 healthy adults were included. Hcys, vitamin B12 and folic acid levels were measured in both groups. Clinical history and thromboembolic events were investigated.

RESULTS: The average Hcys level in the UC patients was 13.3 ± 1.93 μmmol/L (range 4.60-87) and was higher than the average Hcys level of the control group which was 11.2 ± 3.58 μmmol/L (range 4.00-20.8) (P < 0.001). Vitamin B12 and folic acid average values were also lower in the UC group (P < 0.001). When multivariate regression analysis was performed, it was seen that folic acid deficiency was the only risk factor for hyperhomocysteinemia. Frequencies of thromboembolic complications were not statistically significantly different in UC and control groups. When those with and without a thrombosis history in the UC group were compared according to Hcys levels, it was seen that there were no statistically significant differences. A negative linear relationship was found between folic acid levels and Hcys.

CONCLUSION: We could not find any correlations between Hcys levels and history of prior thromboembolic events.

Intestinal metabolism of sulfur amino acids

The gastrointestinal tract (GIT) is a metabolically significant site of sulfur amino acid (SAA) metabolism in the body and metabolises about 20 % of the dietary methionine intake which is mainly transmethylated to homocysteine and trans-sulfurated to cysteine. The GIT accounts for about 25 % of the whole-body transmethylation and trans-sulfuration. In addition, in vivo studies in young pigs indicate that the GIT is a site of net homocysteine release and thus may contribute to the homocysteinaemia. The gut also utilises 25 % of the dietary cysteine intake and the cysteine uptake by the gut represents about 65 % of the splanchnic first-pass uptake. Moreover, we recently showed that SAA deficiency significantly suppresses intestinal mucosal growth and reduces intestinal epithelial cell proliferation, and increases intestinal oxidant stress in piglets. These recent findings indicate that intestinal metabolism of dietary methionine and cysteine is nutritionally important for intestinal mucosal growth. Besides their role in protein synthesis, methionine and cysteine are precursors of important molecules. S-adenosylmethionine, a metabolite of methionine, is the principal biological methyl donor in mammalian cells and a precursor for polyamine synthesis. Cysteine is the rate-limiting amino acid for glutathione synthesis, the major cellular antioxidant in mammals. Further studies are warranted to establish how SAA metabolism regulates gut growth and intestinal function, and contributes to the development of gastrointestinal diseases. The present review discusses the evidence of SAA metabolism in the GIT and its functional and nutritional importance in gut function and diseases.