Hyperhomocysteinaemia in chronic liver diseases: role of disease stage, vitamin status and methylenetetrahydrofolate reductase genetics

Circulating soluble CD36 as a novel biomarker for progression and prognosis of HBV-related liver diseases

BACKGROUND

Our previous study suggested CD36 may be a positive regulator of hepatitis B virus (HBV) replication in vitro. Therefore, the present study aimed to investigate whether circulating soluble CD36 (sCD36) could serve as a diagnostic and prognostic biomarker for HBV-related liver diseases based on the clinic collected data.

METHODS

A total of 282 subjects were divided into healthy controls (HC, n = 47), chronic hepatitis B (CHB, n = 68), HBV-related liver cirrhosis (HBV-LC, n = 167). Soluble CD36 in plasma was measured by ELISA, and monocyte or platelet CD36 expression was determined by flow cytometry.

RESULTS

There was a step-wise increase of sCD36 with the progression of chronic HBV infection, and it was the highest in the HBV- LC group with liver failure (1.50, IQR:1.04-2.00) as compared with HC (0.38, IQR:0.27-0.38), CHB (0.75, IQR:0.40-1.13), and HBV-LC without liver failure (1.02, IQR,0.61-1.35) group. Circulating sCD36 was not correlated with serum HBV DNA levels, but correlated with liver function parameters. Additionally, ROC analysis confirmed sCD36 could be used to predict liver failure for HBV-LC patients, which yielded an AUC of 0.775 with 71.0% sensitivity and 72.2% specificity. Multivariate logistic regression analysis revealed sCD36 is an independent risk factor in predicting liver failure. Moreover, plasma sCD36 in HBV-LC patients was significantly correlated with prognostic indices, including MELD, MELD-Na and CHILD-PUGH scores. On the other hand, CD36 expression on monocytes or platelets was positively correlated with plasma sCD36 levels, whereas they were not strongly associated with the disease severity.

CONCLUSION

Circulating sCD36 could be used as a novel noninvasive biomarker for predicting liver failure and prognosis in chronic HBV infected patients.

Protective effect of aqueous extract of Nigella sativa on Oxidative Enzymes, Homocysteine, and Lipids in Methionine induced Hyperhomocysteinemic rats

Hyperhomocysteinemia has emerged as an independent risk factor for development of various diseases such as coronary, cerebrovascular and peripheral arterial occlusive diseases. Its association is found with atherosclerosis, cancer and some other aged-related illnesses including Alzheimer’s disease. The present study was designed to investigate the homocysteine lowering potential, effect on lipids and oxidative enzymes of standardized aqueous extract of Nigella sativa seeds (100 and 200 mg/kg body weight, p.o.) in hyperhomocysteinemia induced by L-methionine. Hyperhomocysteinemia was induced in wistar albino rats by methionine treatment (1 g/kg, p.o.) for 30 days. Folic acid (100 mg/kg, p.o.) given to rats as a standard drug treatment. Rats were fed with the aqueous extract of Nigella sativa (100 and 200 mg/kg, p.o.) for 30 days. The results of the present study after treatment with Nigella sativa aqueous extracts in two doses of 100 and 200 mg/kg body weight, showed lipid lowering, cardio- and neuro-protective potential of Nigella sativa. The results of test drug were compared with folic acid, a standard positive control. The present study results indicate that the aqueous extract of Nigella sativa seeds treatment protect the antioxidant defense against hyperhomocysteinemia, hyperlipidemia and oxidative stress in methionine-induced rat model.

The role of genetic mutation in alcoholic liver disease

Background

Alcoholic liver disease (ALD) is the world’s most common type of liver disease caused due to overconsumption of alcohol. The liver supports the best level of tissue damage by hefty drinking since it is the binding site of ethanol digestion. This disease can progress to alcoholic steatohepatitis from alcoholic fatty liver, which implies steatosis has become the most punctual reaction to hefty drinking and is portrayed by the deposition of fat hepatocytes. In addition, steatosis can advance to steatohepatitis, a more extreme, provocative sort of liver damage described by hepatic inflammation. Constant and unnecessary liquor utilization delivers a wide range of hepatic sores, fibrosis and cirrhosis, and sometimes hepatocellular carcinoma. Most people consuming > 40 g of liquor each day create alcoholic fatty liver (AFL); notwithstanding, just a subset of people will grow further developed infection. Hereditary, epigenetic, and non-hereditary components may clarify the impressive interindividual variety in the ALD phenotype.

Main body

This systematic review is to classify new candidate genes associated with alcoholic liver disorders, such as RASGRF2, ALDH2, NFE2L2, ADH1B, PNPLA3, DRD2, MTHFR, TM6SF2, IL1B, and CYP2E1, MBOAT7 as well as to revise the functions of each gene in its polymorphic sequence. The information obtained from the previously published articles revealed the crucial relationship between the genes and ALD and discussed each selected gene’s mechanism.

Conclusion

The aim of this review is to highlight the candidate genes associated with the ALD, and the evidence of this study is to deliberate the part of genetic alterations and modifications that can serve as an excellent biological maker, risk predictors, and therapeutic targets for this disease.

Associations between methylenetetrahydrofolate reductase polymorphisms and hepatocellular carcinoma risk: An update meta-analysis and trial sequential analysis

AIM

To evaluate the associations between the methylenetetrahydrofolate reductase (MTHFR) single-nucleotide polymorphisms (SNPs) and hepatocellular carcinoma (HCC) with meta-analysis and trial sequential analysis.

METHODS

PubMed, Embase, the Google Scholar, Wan fang database, VIP database, and China National Knowledge Infrastructure were extensively searched before April 2021. Odds ratios (ORs) and 95% confidence interval (95% CI) were calculated. Review Manager Version 5.3, STATA version 12.0 and TSA 0.9.5.10 Beta software were used.

RESULTS

Nineteen studies with 6941 HCC patients and 9436 controls were finally included. The MTHFR rs1801133 (C677T) SNP was associated with increased HCC risk under heterozygote genetic model (OR = 1.10, 95% CI = [1.01, 1.20]). For Subgroup analysis, increased risks of HCC were detected in Mongoloid, Chinese. For MTHFR rs1801131 (A1298C) SNP, increased risk of HCC was only observed in Caucasians (allelic: OR = 1.86, 95% CI = [1.49, 2.31]; homozygote: OR = 3.39, 95% CI = [2.18, 5.27]), interesting decreased risk was detected in Mongoloid (recessive: OR = 0.30, 95% CI = [0.15, 0.58]; homozygote: OR = 0.41, 95% CI = [0.24, 0.72]). Sensitivity analysis indicated stability in our results. Publication bias was not detected based on Begg test and Egger test. Trial sequential analysis indicated further studies to confirm the associations in MTHFR C677T polymorphism.

CONCLUSION

The MTHFR rs1801133 SNP was associated with an increased risk of HCC in Mongoloid population especially in Chinese. Increased HCC risk is also observed in Caucasian population for the MTHFR rs1801131 SNP, and decreased risk of HCC is remarkably discovered in Mongoloid and Chinese subgroups, which need further validation.

Association of MTHFR and TYMS gene polymorphisms with the susceptibility to HCC in Egyptian HCV cirrhotic patients

Identification of host genetic factors influencing the risk of developing hepatocellular carcinoma (HCC) in patients with chronic hepatitis C virus (HCV) infection may help to refine patients' selection to benefit from specific preventative measures and/or adapted screening policies. Thus, this study aimed to investigate the association of MTHFR c.677C > T and c.1298A > C in addition to TYMS 3'-UTR 6-bp ins/del polymorphisms with the susceptibility to HCV-related HCC in an Egyptian population. Polymerase chain reaction-restriction fragment length polymorphism was performed to genotype the polymorphisms in 194 HCV-infected patients subdivided into liver cirrhotic (LC, n = 104) and HCC (n = 90) patients as well as 100 healthy subjects. In healthy controls, the MTHFR c.677C > T polymorphism under the homozygous and recessive models (p = 0.005) and the c.1298A > C polymorphism under all the tested genetic models (p-values range from < 0.001 to 0.007) were associated with an increased risk of HCC. In LC patients, the MTHFR c.677C > T polymorphism under the homozygous, dominant, and recessive models (p-values range from 0.001 to 0.007), as well as MTHFR c.1298A > C under the homozygous model only (p = 0.014), increased the susceptibility to HCC. The C/C and T/C haplotypes of MTHFR c.677C > T and MTHFR c.1298A > C polymorphisms were contributed to an increased risk of healthy subjects to develop HCC (p-values range from < 0.001 to 0.015), while only the T/C haplotype was associated with the progression of HCC in LC patients (p = 0.001). In conclusion, MTHFR c.677C > T and c.1298A > C in addition to their haplotypes may contribute to the development of HCV-related HCC in an Egyptian population. These findings may aid in the early diagnosis and management of HCC.

Anticoagulation Favors Thrombus Recanalization and Survival in Patients With Liver Cirrhosis and Portal Vein Thrombosis: Results of a Meta-Analysis

INTRODUCTION

Benefit and risk of anticoagulation in cirrhotic patients with portal vein thrombosis (PVT) remain controversial, especially in those with asymptomatic PVT and in non-liver transplant candidates. Furthermore, the predictors of portal vein recanalization and bleeding events after anticoagulation are critical for making clinical decisions, but still unclear. We conducted a meta-analysis to investigate the outcomes of anticoagulation for PVT in liver cirrhosis and explore the predictors of portal vein recanalization and bleeding events after anticoagulation.

METHODS

All studies regarding anticoagulation for PVT in liver cirrhosis were searched via PubMed, EMBASE, and Cochrane Library databases. Thrombotic outcomes, bleeding events, and survival were compared between anticoagulation and non-anticoagulation groups. Predictors of portal vein recanalization and bleeding events were pooled. Risk ratios (RRs) or mean differences (MDs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Thirty-three studies including 1696 cirrhotic patients with PVT were included. Anticoagulation significantly increased portal vein recanalization (RR = 2.61; 95% CI 1.99-3.43; P < 0.00001) and overall survival (RR = 1.11; 95% CI 1.03-1.21; P = 0.01) and decreased thrombus progression (RR = 0.26; 95% CI 0.14-0.49; P < 0.0001). Anticoagulation did not significantly influence overall bleeding (RR = 0.78; 95% CI 0.47-1.30; P = 0.34). Early initiation of anticoagulation (RR = 1.58; 95% CI 1.21-2.07; P = 0.0007) significantly increased portal vein recanalization. Child-Pugh class B and C (RR = 0.77; 95% CI 0.62-0.95; P = 0.02) and higher MELD score (MD = - 1.48; 95% CI - 2.20-0.76; P < 0.0001) were significantly associated with decreased portal vein recanalization. No predictor significantly associated with bleeding events was identified.

CONCLUSIONS

Early initiation of anticoagulation should be supported in liver cirrhosis with PVT. Predictors of portal vein recanalization should be taken into consideration to identify those who may not benefit from anticoagulation.

REGISTRATION

The work was registered in PROSPERO with registration no. CRD42020157142.

No Association of Homocysteine, Anticardiolipin Antibody, and Anti-β2 Glycoprotein I Antibody With Portal Venous System Thrombosis in Liver Cirrhosis

Portal venous system thrombosis (PVST), a common complication of liver cirrhosis, is closely associated with thrombophilia. To explore the association of homocysteine (Hcy), anticardiolipin antibody (aCL), and anti-β2 glycoprotein I antibody (aβ₂GPI), which are possible thrombophilic factors, with PVST in liver cirrhosis. Overall, 654 non-malignant patients (219 with and 435 without liver cirrhosis) admitted between January 2016 and June 2020 were retrospectively evaluated. Presence of PVST, degree of main portal vein (MPV) thrombosis, and clinically significant PVST were identified. Hcy level, hyperhomocysteinemia (HHcy), aCL positivity, and aβ₂GPI positivity were compared according to the presence of liver cirrhosis and PVST. Positive aβ₂GPI was significantly more frequent in patients with liver cirrhosis than those without, but Hcy level and proportions of HHcy and positive aCL were not significantly different between them. PVST could be evaluated in 136 cirrhotic patients. Hcy level [10.57 μmol/L (2.71-56.82) versus 9.97 μmol/L (2.05-53.44); P = 0.796] and proportions of HHcy [4/44 (9.1%) versus 13/81 (16.0%); P = 0.413] and positive aCL [1/23 (4.3%) versus 10/52 (19.2%); P = 0.185] and aβ₂GPI [9/23 (39.1%) versus 21/52 (40.4%); P = 0.919] were not significantly different between cirrhotic patients with and without PVST. There was still no significant association of Hcy level, HHcy, aCL, or aβ₂GPI with PVST based on Child-Pugh classification, MPV thrombosis >50%, and clinically significant PVST. Hcy, aCL, and aβ₂GPI may not be associated with PVST in liver cirrhosis, suggesting that routine screening for Hcy, aCL, and aβ₂GPI should be unnecessary in such patients.

MTHFR rs1801133 Polymorphism Is Associated With Liver Fibrosis Progression in Chronic Hepatitis C: A Retrospective Study

Background: The MTHFR (methylenetetrahydrofolate reductase) rs1801133 polymorphism leads to higher circulating levels of homocysteine, which is related to several liver diseases. We aimed to evaluate the relationship between MTHFR rs1801133 polymorphism and liver fibrosis progression in HCV-infected patients. Methods: We conducted a preliminary retrospective cohort study in 208 non-cirrhotic HCV-infected patients. These subjects had at least two liver stiffness measurements (LSM), which were assessed using transient elastography, and no patient had cirrhosis at baseline. We analyzed the association between MTHFR rs1801133 and outcome variables using Generalized Linear Models. Results: HCV-infected patients were 47 years old, around 54% were males, a low frequency of high alcohol intake (13.5%) or prior use of intravenous drugs (10.1%). A total of 26 patients developed cirrhosis (LSM1 ≥ 12.5) during a median follow-up of 46.6 months. The presence of the rs1801133 C allele showed an inverse association with the LSM2/LSM1 ratio (adjusted AMR = 0.90; 95%CI = 0.83-0.98; p = 0.020) and the cirrhosis progression (adjusted OR = 0.43; 95%CI = 0.19-0.95; p = 0.038). Besides, rs1801133 CT/CC genotype had an inverse association with the LSM2/LSM1 ratio (adjusted AMR = 0.80; 95%CI = 0.68-0.95; p = 0.009) and the cirrhosis progression (adjusted OR= 0.21; 95%CI = 0.06-0.74; p = 0.015). Conclusions: MTHFR rs1801133 C allele carriers presented a diminished risk of liver fibrosis progression and development of cirrhosis than rs1801133 T allele carriers. This statement supports the hypothesis that MTHFR rs1801133 polymorphism appears to play a crucial role in chronic hepatitis C immunopathogenesis.

Hyperhomocysteinemia in patients with acute porphyrias: A potentially dangerous metabolic crossroad?

BACKGROUND

Acute porphyrias (AP) are characterized by heme deficiency and induction of hepatic 5-aminolevulinate synthase (ALAS1). Hyperhomocysteinemia (HHcy) is associated with endothelial damage, neurotoxicity and increased risk for vascular diseases. Interestingly, both heme biosynthesis and sulphur amino acid metabolism require vitamin B6, (Pyridoxal-phosphate, PLP) an important cofactor of ALAS1 and of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CGL) enzymes that catabolize homocysteine (Hcy). Moreover, heme itself is an important cofactor for CBS.

AIM

to assess plasma Hcy status and HHcy main determinants in patients with AP.

MATERIALS AND METHODS

A total of 46 patients with AP (31 with Acute Intermittent Porphyria,15 with Variegate Porphyria) were assessed for clinical status (symptomatic vs. asymptomatic), serum Hcy, Cysteine (Cys), Vit.B6, Vit.B12, red blood cell folates and urinary delta-aminolevulinic acid (ALA) and porphobilinogen(PBG) levels (mean of six measurements).

RESULTS

Symptomatic AP patients had significantly higher urinary ALA and PBG levels, plasma Hcy, HHcy prevalence and Hcy/Cys ratio when compared to asymptomatic carriers of AP. Even though no significant correlation was observed between ALA/PBG urinary levels and serum Hcy levels, patients with higher levels of ALA and PBG had significantly higher levels of Hcy, a higher prevalence of moderate-to severe HHcy and serum PLP levels below the 25^th percentile of a reference assessment with 300 healthy Italian subjects(<45nmol/L).

CONCLUSIONS

Most patients with symptomatic AP present HHcy resulting from alterations in sulphur amino acid metabolism. HHcy may represent an indirect marker of ALAS1 induction and its prevalence may be suggestive of a role of HHcy in the pathogenesis and/or comorbidities of AP.

Review of Serum Biomarkers and Models Derived from Them in HBV-Related Liver Diseases

A series of predictive scoring systems is available for stratifying the severity of conditions and assessing the prognosis in patients with HBV-related liver diseases. We show nine of the most popular serum biomarkers and their models (i.e., serum cystatin C, homocysteine, C-reactive protein, C-reactive protein to albumin ratio, aspartate aminotransferase to platelet ratio index, fibrosis index based on four factors, gamma-glutamyl transpeptidase to platelet ratio, albumin-bilirubin score, and gamma-glutamyl transpeptidase to albumin ratio) that have gained great interest from clinicians. Compared with traditional scoring systems, these serum biomarkers and their models are easily acquired, simple, and relatively inexpensive. In the present review, we summarize the latest studies focused on these serum biomarkers and their models as diagnostic and prognostic indexes in HBV-related liver diseases.

Rapid screening of hepatitis B using Raman spectroscopy and long short-term memory neural network

This study presents a rapid method to screen hepatitis B patients using serum Raman spectroscopy combined with long short-term memory neural network (LSTM). The serum samples taken from 435 hepatitis B patients and 699 non-hepatitis B people were measured in this experiment. Specific biomolecular changes in three groups of serum samples could be seen in the tentative assignment of Raman peaks. First, principal component analysis (PCA) was used for extracting key features of spectral data, which reduces the dimension of the multidimensional spectrum. Then, LSTM is used to train the spectral data. Finally, the full connection layer completes the classification of HBV. The diagnostic accuracy of the first LSTM model is 97.32%, and the value of AUC is 0.995. The results from the study demonstrate that the combination of serum Raman spectroscopy technique and LSTM provides an effective technical approach to the screening of hepatitis B.

Thrombophilia in hepatocellular carcinoma

Background

Chronic liver disease and hepatocellular carcinoma (HCC) can cause a disturbance in the coagulation system. In this study, we aimed to assess the risk factors for venous thromboembolism either acquired or hereditary in patients with HCC.

Results

Serum levels of proteins C and S, AT activity, and lipoprotein (a) were significantly lower in both HCC and cirrhotic patients while homocysteine levels were significantly higher in HCC patients. The prevalence of activated protein C resistance (APCR) and factor V Leiden (FVL) mutation was higher in HCC patients but with no significant differences between the studied groups. With multivariate analysis, prothrombin time, Fbg, protein C and S deficiency, increased lipoprotein (a), hyperhomocysteinemia, APCR, and FVL mutation were independent risk factors for thromboembolic complications in HCC patients.

Conclusions

Thrombophilic abnormalities are prevalent in HCC patients, and they have a substantial increased risk of venous thromboembolism.

Mild Methylenetetrahydrofolate Reductase Deficiency Alters Inflammatory and Lipid Pathways in Liver

SCOPE

Dietary and genetic folate disturbances can lead to nonalcoholic fatty liver disease (NAFLD). A common variant in methylenetetrahydrofolate reductase (MTHFR 677C→T) causes mild MTHFR deficiency with lower 5-methyltetrahydrofolate for methylation reactions. The goal is to determine whether mild murine MTHFR deficiency contributes to NAFLD-related effects.

METHODS AND RESULTS

Wild-type and Mthfr^+/- mice, a model for the human variant, are fed control (CD) or high-fat (HFAT) diets for 8 weeks. On both diets, MTHFR deficiency results in decreased S-adenosylmethionine, increased S-adenosylhomocysteine, and decreased betaine with reduced methylation capacity, and changes in expression of several inflammatory or anti-inflammatory mediators (Saa1, Apoa1, and Pon1). On CD, MTHFR deficiency leads to microvesicular steatosis with expression changes in lipid regulators Xbp1s and Cyp7a1. The combination of MTHFR deficiency and HFAT exacerbates changes in inflammatory mediators and introduces additional effects on inflammation (Saa2) and lipid metabolism (Nr1h4, Srebf1c, Ppara, and Crot). These effects are consistent with increased expression of pro-inflammatory HDL precursors and greater lipid accumulation. MTHFR deficiency may enhance liver injury through alterations in methylation capacity, inflammatory response, and lipid metabolism.

CONCLUSION

Individuals with the MTHFR variant may be at increased risk for liver disease and related complications, particularly when consuming high-fat diets.

Homocysteine: a new diagnostic marker in spontaneous bacterial peritonitis

BACKGROUND AND AIMS

The diagnosis of spontaneous bacterial peritonitis (SBP) depends primarily on a polymorphonuclear leukocyte cell count more than 250/mm. This method is invasive, and not diagnostic in all variants of SBP; we aimed to assess serum homocysteine as a precise indicative marker for the diagnosis of all variants of SBP.

PATIENTS AND METHODS

A total 323 consecutive ascitic patients were registered in this prospective work. Serum and ascitic fluid of homocysteine were evaluated utilizing an enzyme-linked immunosorbent assay.

RESULTS

Participants were classified into a non-SBP group, including 262 participants and 61 patients with SBP. Serum and ascitic homocysteine were considerably elevated in the SBP group than in the non-SBP group (17.94±7.57 vs. 11.75±5.68 μmol/l; P<0.001 and 14.70±5.45 vs. 9.75±4.55 μmol/l; P<0.001). At a cutoff value of 17.79 μmol/l, serum homocysteine had 89.3% specificity and 95.1% sensitivity for distinguishing SBP (area under the curve: 0.932) and, at a cutoff value of 16.1 μmol/l, ascitic homocysteine had 84.4% specificity and 92.7% sensitivity for distinguishing SBP (area under the curve: 0.901). Both were positively correlated with the polymorphonuclear count, C-reactive protein, Child-Pugh score, and Model For End-Stage Liver Disease score as well as negatively correlated with the protein content in the ascitic fluid and estimated glomerular filtration rate. After SBP therapy, there was a marked reduction in serum and ascitic homocysteine levels.

CONCLUSION

This study demonstrates that serum and ascitic homocysteine are considerably higher in SBP participants versus non-SBP patients. Serum homocysteine may provide a reliable and noninvasive diagnostic marker for all variants of SBP.

The MTHFR polymorphism affect the susceptibility of HCC and the prognosis of HCC liver transplantation

BACKGROUND

Methylenetetrahyfrofolate reductase (MTHFR) is the key enzyme for one carbon and folate metabolism. Previous studies have drawn different conclusions about the relationship between the mutation of MTHFR and hepatocellular carcinoma (HCC) occurrence. MTHFR polymorphisms' influence on liver transplantation for HCC recurrence has yet not been reported. Aim of this study was to clarify the impact of MTHFR polymorphism on hepatocarcinogenesis and the prognosis of liver transplant recipient with HCC.

METHODS

This study enrolled 244 HCC patients and 487 healthy individuals in Chinese Han population to analyze the influence of MTHFR polymorphism on HCC susceptibility first. Furthermore, this research choose another 100 donors' and 104 recipients' specimens to detect the association between polymorphism of MTHFR and post-transplant HCC recurrence.

RESULT

rs1801131 polymorphism A to C was associated with the occurrence of HCC in Chinese Han population (p < 0.05), especially in age exceeding 50 years (p < 0.01). No association was observed with rs1801133 polymorphism and HCC occurrence. The mean tumor-free survival for recipients with donor liver graft rs1801133 C to T variants was shorter than CC type (12.63 ± 3.84 vs 22.43 ± 4.74 months, p < 0.05). Multivariate analysis revealed that Donor rs1801133 and Hangzhou criteria were two independent prognostic factors for tumor-free survival (p < 0.05). Neither donor rs1801131 polymorphism nor recipients' MTHFR polymorphisms was associated with HCC recurrence.

CONCLUSION

This study demonstrated that MTHFR polymorphism was associated with HCC occurrence and post-transplant HCC recurrence. rs1801131 mutation A to C is a valuable molecular biomarker for predicting HCC occurrence in Chinese Han population. Donor MTHFR rs1801133 C to T polymorphism could present as a promising prognostic biomarkers for HCC recurrence in liver transplant recipients.

Hyperhomocysteinemia results from and promotes hepatocellular carcinoma via CYP450 metabolism by CYP2J2 DNA methylation

Hyperhomocysteinemia (HHcy) can result from liver disease or dysfunction and further alters intracellular lipid metabolism. Cytochrome P450 (CYP) arachidonic acid epoxygenases are expressed in human cancers and promote cancer metastasis. This study explored the interaction of Hcy and CYP450 metabolism in hepatocellular carcinoma (HCC). The levels of 4-epoxyeicosatrienoic acid (EET) isomers and their generative enzyme CYP2J2 level as well as intracellular Hcy level were higher in 42 cases of HCC than in paired non-tumor tissue. Elevated Hcy-decreased DNA methylation on SP1/AP1 binding motifs and enhancement on the CYP2J2 promoter via ERK1/2 signaling was essential for CYP2J2 upregulation and EET metabolism. Increased Hcy level enhanced the neoplastic cellular phenotype, which was reversed by CYP2J2 knockdown in vitro. Furthermore, tumor growth and size as well as patterns of CYP2J2 expression and DNA demethylation were increased with HHcy in mice induced orthotopically by 2% (wt/wt) L-methionine with or without folate deficiency. Moreover, the effect was attenuated by shRNA knockdown of CYP2J2. Thus, HHcy results from but can also promote hepatocarcingenesis via CYP450-EET metabolism by crosstalk of DNA demethylation of CYP2J2 and ERK1/2 signaling.

The Association between Pediatric NAFLD and Common Genetic Variants

Non-alcoholic fatty liver disease (NAFLD) is one of the most common complications of obesity. Several studies have shown that genetic predisposition probably plays an important role in its pathogenesis. In fact, in the last few years a large number of genetic studies have provided compelling evidence that some gene variants, especially those in genes encoding proteins regulating lipid metabolism, are associated with intra-hepatic fat accumulation. Here we provide a comprehensive review of the gene variants that have affected the natural history of the disease.

The MTHFR C677T mutation is not a risk factor recognized for HBV-related HCC in a population with a high prevalence of this genetic marker

BACKGROUND

Polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene can affect disease progression in HBV infection. However, the results from different reports are inconsistent. The aim of this study was to investigate the association between the MTHFR C677T polymorphism and the outcome of HBV infection in a Tianjin Han population.

METHODS

TaqMan SNP genotyping was employed to determine the alleles and genotypes of MTHFR C677T in 2511 subjects from various stages of HBV infection and 549 healthy controls.

RESULTS

Of the 3060 subjects, the genotypic frequencies were CT 48.9%, TT 29.3% and CC 21.8%; the allelic frequencies were T 53.8% and C 46.2%. There was no significant difference in genotypic or allelic distribution among the different disease groups. When either healthy subjects or self-limited subjects were used as controls, the TT genotype and the T allele conferred protective effects against hepatocellular carcinoma (HCC) (HCC vs healthy subjects: OR=0.588, 95% CI=0.413-0.836, P=0.003; OR=0.768, 95% CI=0.645-0.915, P=0.003, respectively. HCC vs self-limited subjects: OR=0.598, 95% CI=0.404-0.886, P=0.010; OR=0.772, 95% CI=0.635-0.940, P=0.010, respectively). After sub-stratification by gender, the prevalence of the TT genotype or T allele was the lowest in the male HCC group (TT 23.5%, T 49.8%). The protective effects of the TT genotype and the T allele were observed in male HCC and cirrhotic subjects (HCC vs self-limited subjects: OR=0.470, 95% CI=0.288-0.766, P=0.002; OR=0.681, 95% CI=0.535-0.866, P=0.002, respectively. Liver cirrhosis vs self-limited subjects: OR=0.624, 95% CI=0.392-0.992, P=0.046; OR=0.791, 95% CI=0.627-0.998, P=0.048, respectively), but not in female. When the subjects were stratified according to the clinical features, no statistically significant difference in the genotypic distribution was observed (P>0.05).

CONCLUSIONS

The TT genotype and T allele of MTHFR C677T may confer a protective effect on disease progression to HCC in HBV-infected individuals, especially among male patients, in a population with a high prevalence of this genetic marker.

Clinical Study of Serum Homocysteine and Non-Alcoholic Fatty Liver Disease in Euglycemic Patients

BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease. NAFLD includes a spectrum of hepatic pathologies: simple fatty liver, steatohepatitis and cirrhosis. Insulin resistance may contribute to NAFLD. The liver plays an important role in the production and metabolism of homocysteine (HCY), which is known to be an independent risk factor for cardiovascular disease. High HCY level can aggravate NAFLD by increasing the reactive oxygen species and activating oxidative stress. In this study, we investigated the relationship between HCY and NAFLD in euglycemic patients. MATERIAL AND METHODS A total of 1143 euglycemic patients were recruited: 519 patients with non-alcoholic fatty liver disease (NAFLD) and 624 sex and age-matched controls without NAFLD. RESULTS The NAFLD group had significantly higher HCY level (13.78±5.84 vs. 11.96±3.58 mmol/L, p<0.001), as well as higher body mass index (BMI), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), triglyceride (TG), glutamic-pyruvic transaminase (ALT), glutamic-oxalacetic transaminase (AST), fasting plasma glucose (FPG), fasting insulin (FINS), homeostasis model assessment for insulin resistance (HOMA-IR), homeostasis model assessment for beta cell function (HOMA-B), and lower high density lipoprotein cholesterol (HDL-C). HCY level was positively correlated with HOMA-IR (r=0.239, p<0.001), TG (r=0.356, p<0.001) and negatively correlated with HDL-C (r=-0.161, p<0.001). In the logistic regression analysis, BMI (beta=0.345, p<0.001), HOMA-IR (beta=0.654, p<0.01), TG (beta=0.881, p<0.001), and HCY (beta=0.04, p=0.044) were the predictors of NAFLD. CONCLUSIONS Higher HCY level existed in NAFLD patients and was correlated with the severity of insulin resistance. HCY is an independent risk factor for NAFLD.

Hyperhomocysteinemia is associated with severity of cirrhosis and negative impact after liver transplantation

BACKGROUND & AIMS

Hyperhomocysteinemia constitutes an independent risk factor for thrombosis and cellular injury promoted by oxidative stress. The clinical significance of hyperhomocysteinemia in cirrhosis and outcomes post-liver transplantation is poorly documented. In this study, we aimed to determine the prevalence of hyperhomocysteinemia in cirrhosis, evaluate its association with thrombosis and severity of liver disease, and its impact on survival after liver transplantation.

METHODS

We analysed 450 patients with cirrhosis who received a liver transplant between 2001 and 2010. Data were recovered from medical charts and homocysteine serum levels were determined before liver transplantation in all patients.

RESULTS

Median age was 53 years (range, 18-72 years) and 308 patients were males (68%). Cirrhosis aetiology was hepatitis C (37%), autoimmune liver disease (22%), alcohol (16%) and others (25%). The median homocysteine level was 11 μmol/L (range, 4-221 μmol/L) and 165 patients (37%) had hyperhomocysteinemia. The MELD (23 ± 10 vs. 20 ± 9 points, P < 0.001), and Child-Pugh (11 ± 2 vs. 9 ± 2 points, P < 0.001) scores were higher in patients with hyperhomocysteinemia. Episodes of thrombosis occurred in 91 patients (20%), but there was no significant difference in patients with or without hyperhomocysteinemia (19 vs. 21%, P = 0.6). Hyperhomocysteinemia was associated with reduced graft (105 ± 4 vs. 119 ± 2 months; P = 0.005), and patient survival (125 ± 33 vs. 131 ± 2 months; P = 0.006).

CONCLUSIONS

Hyperhomocysteinemia is frequently present in patients with cirrhosis and is associated with severe liver disease and reduced graft and patient survival after liver transplantation. The negative impact hyperhomocysteinemia has on graft and patient survival is not related to thrombosis.

Hyperhomocysteinemia and MTHFR C677T polymorphism in patients with portal vein thrombosis complicating liver cirrhosis

BACKGROUND

Portal vein thrombosis (PVT) is serious complication of liver cirrhosis (LC), especially in the presence of hepatocellular carcinoma (HCC). The liver plays a key role in homocysteine (Hcy) metabolism: mild hyperhomocysteinemia (HHcy) has been described in LC. HHcy is a risk factor for deep vein thrombosis. Methylen-tetrahydrofolate-reductase (MTHFR) C677T polymorphism is the commonest determinant of mild HHcy and has been involved also in cancer development.

AIM

To investigate a possible relation between HHcy, MTHFR status, HCC and PVT in patients affected by LC.

MATERIALS AND METHODS

100 patients affected by LC, 38 with (PVT group, 24 with HCC) and 62 without PVT (LC group, 14 with HCC) sex-, age-, liver disease stage and etiology-matched were assessed for thrombophilia, smoking status, plasma Hcy, MTHFRC677T polymorphism and homocysteine-related vitamin status.

RESULTS

A higher prevalence of HCC, HHcy and MTHFR TT status was observed in PVT group. No significant difference in vitamin status was observed between groups. Patients with HCC showed significantly higher plasma Hcy and higher prevalence of HHcy than patients without HCC. They had also higher prevalence of MTHFR TT status. In patients with TT status (n=11) and HCC, 10 had HHcy e 9 had PVT.

CONCLUSIONS

Mild HHcy is associated to LC may have a role in PVT development and assessment of plasma Hcy may be suggested in patients with LC (especially if complicated by HCC). Association between HCC and MTHFR TT status is intriguing, due the postulated role for this polymorphism in cancer: it may represent a possible link between HCC and PVT.

Vitamin B-6 Supplementation Could Mediate Antioxidant Capacity by Reducing Plasma Homocysteine Concentration in Patients with Hepatocellular Carcinoma after Tumor Resection

Vitamin B-6 has a strong antioxidative effect. It would be useful to determine whether vitamin B-6 supplementation had effects on antioxidant capacities in patients with hepatocellular carcinoma (HCC) who had recently undergone tumor resection. Thirty-three HCC patients were randomly assigned to either the placebo (n = 16) group or the vitamin B-6 50 mg/d (n = 17) group for 12 weeks. Plasma pyridoxal 5′-phosphate, homocysteine, indicators of oxidative stress, and antioxidant capacities were measured. Plasma homocysteine in the vitamin B-6 group was significantly decreased at week 12, while the level of trolox equivalent antioxidant capacity (TEAC) was significantly increased at the end of the intervention period. Vitamin B-6 supplementation had a significant reducing effect on the change of plasma homocysteine (β = −2.4, p = 0.02) but not on the change of TEAC level after adjusting for potential confounders. The change of plasma homocysteine was significantly associated with the change of TEAC after adjusting for potential confounders (β = −162.0, p = 0.03). Vitamin B-6 supplementation seemed to mediate antioxidant capacity via reducing plasma homocysteine rather than having a direct antioxidative effect in HCC patients who had recently undergone tumor resection. The clinical trial number is NCT01964001, ClinicalTrials.gov.

Folate and vitamin B-6 status are not associated with homocysteine, oxidative stress and antioxidant capacities in patients with hepatocellular carcinoma

The purpose of this study was to study the effects of serum folate and plasma pyridoxal 5'-phosphate (PLP) on plasma homocysteine, oxidative stress and antioxidant capacities in 44 hepatocellular carcinoma (HCC) patients and 56 healthy controls. The responses of folate, vitamin B-6, homocysteine, oxidative stress and antioxidant enzyme activities in HCC patients before and after tumor resection were also determined. Patients with HCC before tumor resection had significantly lower folate, PLP, homocysteine, glutathione peroxidase and superoxide dismutase levels, but higher malondialdehyde, total antioxidant capacity and glutathione S-transferase activity when compared with healthy controls. Oxidative stress was significantly decreased to a level similar to that of healthy controls after tumor resection in the HCC group. There were no associations of folate and PLP with plasma homocysteine, indicators of oxidative stress and antioxidant capacities. Serum folate and plasma PLP were not significant factors affecting plasma homocysteine, oxidative stress and antioxidant capacities in patients with HCC.

PAI-1 4G-4G and MTHFR 677TT in non-hepatitis C virus/hepatitis B virus-related liver cirrhosis

AIM: To evaluate the different roles of thrombophilia in patients with and without viral etiology. The thrombophilic genetic factors (THRGFs), PAI-1 4G-4G, MTHFR 677TT, V Leiden 506Q and prothrombin 20210A, were studied as risk factors in 1079 patients with liver cirrhosis (LC), enrolled from January 2000 to January 2014.

METHODS: All Caucasian LC patients consecutively observed in a fourteen-year period were included; the presence of portal vein thrombosis (PVT) and Budd Chiari syndrome (BCS) was registered. The differences between the proportions of each THRGF with regard to the presence or absence of viral etiology and the frequencies of the THRGF genotypes with those predicted in a population by the Hardy-Weinberg equilibrium were registered.

RESULTS: Four hundred and seventeen/one thousand and seventy-six patients (38.6%) showed thrombophilia: 217 PAI-1 4G-4G, 176 MTHFR C677TT, 71 V Leiden factor and 41 prothrombin G20210 A, 84 with more than 1 THRGF; 350 presented with no viral liver cirrhosis (NVLC) and 729 with, called viral liver cirrhosis (VLC), of whom 56 patients were hepatitis C virus + hepatitis B virus. PAI-1 4G-4G, MTHFR C677TT, the presence of at least one TRHGF and the presence of > 1 THRGF, were statistically more frequent in patients with NVLC vs patients with VLC: All χ² > 3.85 and P < 0.05. Patients with PVT and/or BCS with at least one TRHGF were 189/352 (53.7%). The Hardy-Weinberg of PAI-1 and MTHFR 677 genotypes deviated from that expected from a population in equilibrium in patients with NVLC (respectively χ² = 39.3; P < 0.000 and χ² = 27.94; P < 0.05), whereas the equilibrium was respected in VLC.

CONCLUSION: MTHFR 677TT was nearly twofold and PAI-1 4G-4G more than threefold more frequently found in NVLC vs patients with VLC; the Hardy-Weinberg equilibrium of these two polymorphisms confirms this data in NVLC. We suggest that PAI-1 4G-4G and MTHFR 677TT could be considered as factors of fibrosis and thrombosis mechanisms, increasing the inflammation response, and causing the hepatic fibrosis and augmented intrahepatic vascular resistance typical of LC. PAI-1 4G-4G and MTHFR 677TT screening of LC patients could be useful, mainly in those with NVLC, to identify patients in which new drug therapies based on the attenuation of the hepatic stellate cells activation or other mechanisms could be more easily evaluated.

Low molecular weight heparin in portal vein thrombosis of cirrhotic patients: only therapeutic purposes?

Cirrhosis has always been regarded as hemorrhagic coagulopathy caused by the reduction in the hepatic synthesis of procoagulant proteins. However, with the progression of liver disease, the cirrhotic patient undergoes a high rate of thrombotic phenomena in the portal venous system. Although the progression of liver failure produces a reduction in the synthesis of anticoagulant molecules, a test able to detect the patients with hemostatic balance shifting towards hypercoagulability has not yet been elaborated. The need of treatment and/or prophylaxis of cirrhotic patients is demonstrated by the increased mortality, the risk of bleeding from esophageal varices, and the mortality of liver transplantation, when portal vein thrombosis (PVT) occurs even if current guidelines do not give indications about PVT treatment in cirrhosis. In view of the general feeling that the majority of cirrhotic patients at an advanced stage may be in a procoagulant condition (suggested by the sharp increase in the prevalence of PVT), it is presumable that a prophylaxis of this population could be of benefit. The safety and the efficacy of prophylaxis and treatment with enoxaparin in patients with cirrhosis demonstrated by a single paper suggest this option only in controlled trials and, currently, there are no sufficient evidences for a recommendation in the clinical practice.

Meta-analysis of MTHFR C677T and A1298C gene polymorphisms: association with the risk of hepatocellular carcinoma

OBJECTIVE

Several studies have indicated an association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and the risk of hepatocellular carcinoma (HCC). However, the conclusions are inconsistent. Therefore, a meta-analysis was performed.

METHODS

Databases like Pubmed, EMBASE, and EBSCO (up to September 2012) were searched to retrieve case-control trials about MTHFR (C677T or A1298C) polymorphisms and HCC. Literatures were independently screened by two researchers according to the inclusion and exclusion criteria. Data were extracted and analyzed by software STATA 11.0.

RESULTS

Nine studies were included with 10 datasets and 5132 cases. C677T polymorphism was associated with HCC risk in a heterozygous model (TT vs. CT: OR=1.20, 95% CI: 1.02-1.40). For the A1298C polymorphism, a significantly decreased HCC risk was found in the dominant, heterozygous and homozygous models (CC vs. AA+AC: OR=0.52, 95% CI: 0.33-0.80; CC vs. AC: OR=0.50, 95% CI: 0.32-0.79; CC vs. AA: OR=0.52, 95% CI: 0.33-0.81). Subgroup analysis stratified by ethnicity and type of control further indicated decreased HCC risks in Asians (CC vs. AA+AC: OR=0.47, 95% CI: 0.26-0.84; CC vs. AC: OR=0.41, 95% CI: 0.24-0.71; CC vs. AA: OR=0.46, 95% CI: 0.27-0.78), studies with controls of healthy people (CC vs. AA: OR=0.54, 95% CI: 0.31-0.93; CC vs. AC: OR=0.54, 95% CI: 0.31-0.94; CC vs. AA+AC: OR=0.55, 95% CI: 0.32-0.94), and controls of non-HCC patients (CC vs. AC: OR=0.43, 95% CI: 0.19-0.96).

CONCLUSIONS

Homozygous carriers of MTHFR C677T mutation are more susceptible to HCC, but homozygous mutations of MTHFR A1298C may play a protective role for developing HCC.

Significant association between MTHFR C677T polymorphism and hepatocellular carcinoma risk: a meta-analysis

Previous studies investigated the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and hepatocellular carcinoma risk, but the impact of MTHFR C677T polymorphism on hepatocellular carcinoma was still unclear, owing to the obvious inconsistence from those studies. This study aimed to quantify the strength of the association between MTHFR C677T polymorphism and hepatocellular carcinoma risk by performing a meta-analysis. We searched the PubMed and Wanfang databases for studies on the association between MTHFR C677T polymorphism and hepatocellular carcinoma risk. We estimated the pooled odds ratios (ORs) with their 95% confidence intervals (95% CIs) to assess the association. Fifteen studies with 8,625 participants were finally included into the meta-analysis. Meta-analyses of total 15 studies suggested that MTHFR C677T polymorphism was significantly associated with an increased risk of hepatocellular carcinoma under two main genetic models (for TT versus CC, OR = 1.19, 95% CI 1.03-1.37, P = 0.016; for TT versus CT/CC, OR = 1.14, 95% CI 1.01-1.28, P = 0.032). Subgroup meta-analyses suggested that MTHFR C677T polymorphism was associated with an increased risk of hepatocellular carcinoma in Asians, but not in Caucasians. Thus, individuals with homozygote genotype TT of MTHFR C677T have obviously increased risk of hepatocellular carcinoma.

Methylenetetrahydrofolate reductase gene polymorphism and serum homocysteine levels in nonalcoholic fatty liver disease

BACKGROUND/AIMS

Nonalcoholic fatty liver disease (NAFLD) is a metabolic disorder characterized by hepatic fat accumulation in the absence of alcohol consumption. Hyperhomocysteinemia is considered an independent risk factor for liver diseases, and the genetic polymorphisms C677T and A1298C in the MTHFR gene have been linked to hyperhomocysteinemia. The purpose of this study was to investigate serum homocysteine (Hcy) concentrations and the MTHFR C677T and A1298C polymorphisms as risk factors for the development of NAFLD.

METHODS

One hundred and thirty-four Brazilian patients with biopsy-proven NAFLD and 134 healthy controls were recruited. The MTHFR C677T and A1298C polymorphisms were detected through polymerase chain reaction restriction fragment length polymorphism. Serum Hcy levels were determined by chemiluminescence.

RESULTS

Serum Hcy levels were higher in NAFLD patients as compared to control subjects, but there were no differences between patients with steatosis and nonalcoholic steatohepatitis. The NAFLD and control groups did not differ in genotypic and allelic frequencies of the MTHFR C677T and A1298C polymorphisms, either. Elevated plasma Hcy levels were positively correlated with age in the NAFLD subjects.

CONCLUSION

The MTHFR C677T and A1298C polymorphisms are not genetic risk factors for the development of NAFLD. Higher Hcy levels exist in NAFLD subjects, but they are not associated with liver disease severity.

Increasing whole grain intake as part of prevention and treatment of nonalcoholic Fatty liver disease

In conjunction with the rise in rates of obesity, there has been an increase in the rate of nonalcoholic fatty liver disease (NAFLD). While NAFLD at least partially originates from poor diet, there is a lack of nutritional recommendations for patients with suspected or confirmed diagnosis of NAFLD, beyond eating a healthy diet, increasing physical activity, and emphasising weight loss. The limited current literature suggests that there may be opportunities to provide more tailored dietary advice for people diagnosed with or at risk of NAFLD. Epidemiological studies consistently find associations between whole grain intake and a reduced risk of obesity and related diseases, yet no work has been done on the potential of whole grains to prevent and/or be a part of the treatment for fatty liver diseases. In this review, we examine the potential and the current evidence for whole grains having an impact on NAFLD. Due to their nutrient and phytochemical composition, switching from consuming mainly refined grains to whole grains should be considered as part of the nutritional guidelines for patients diagnosed with or at risk for fatty liver disease.

The association between MTHFR gene polymorphisms and hepatocellular carcinoma risk: a meta-analysis

Background

The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and hepatocellular carcinoma (HCC) risk was inconsistent and underpowered. To clarify the effects of MTHFR gene polymorphisms on the risk of HCC, a meta-analysis of all available studies relating C677T and/or A1298C polymorphisms of MTHFR gene to the risk of HCC was conducted.

Methods

The authors searched PubMed, EMBASE, Cochrane Library, Web of Science, and Chinese Biomedical Literature database (CBM) for the period up to July 2012. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. Metaregression and subgroup analyses were performed to identify the source of heterogeneity.

Results

Finally, 12 studies with 2,351 cases and 4,091 controls were included for C677T polymorphism and 6 studies with 1,333 cases and 1,878 controls were included for A1298C polymorphism. With respect to A1298C polymorphism, significantly decreased HCC risk was found in the overall population (CC vs. AA: OR = 0.660, 95%CI 0.460–0.946, P = 0.024; recessive model: OR = 0.667, 95%CI = 0.470–0.948, P = 0.024). In subgroup analyses, significantly decreased HCC risk was found in Asian population (CC vs. AA: OR = 0.647, 95%CI = 0.435–0.963; P = 0.032) and population-based studies (CC vs. AA: OR = 0.519, 95%CI = 0.327–0.823; P = 0.005). With respect to C677T polymorphism, no significant association with HCC risk was demonstrated in overall and stratified analyses.

Conclusions

We concluded that MTHFR A1298C polymorphism may play a protective role in the carcinogenesis of HCC. Further large and well-designed studies are needed to confirm this association.

Liver stiffness correlates with methotrexate cumulative dose in patients with rheumatoid arthritis

BACKGROUND

Liver stiffness values were recently proposed to identify patients with methotrexate-induced liver fibrosis. Aim of this study was to assess the clinical and laboratory determinants of the association between liver stiffness, measured by transient elastography, and methotrexate treatment in patients with rheumatoid arthritis in the absence of other factors contributing to liver damage and fibrosis.

METHODS

100 patients with rheumatoid arthritis, with a cumulative methotrexate dose ranging from 1530 to 13,000 mg over a mean period of 7.07±3.89 yrs, were retrospectively evaluated.

RESULTS

The average liver stiffness value in the whole population was 4.93±1.8 kPa, excluding the presence of significant fibrosis. At univariate analysis, a significant correlation was found between liver stiffness and methotrexate cumulative dose, duration of treatment, alanine transaminases levels, body mass index, gamma glutamyl-transpeptidase and the presence of steatosis. At multivariate analysis, a significant association was detected only between liver stiffness and methotrexate cumulative dose. Out of 11 patients with liver stiffness >7.0 kPa, five were subjected to liver biopsy and mild or moderate perisinusoidal fibrosis was detected in two patients with a cumulative dose >4000 mg and liver stiffness >9 kPa.

CONCLUSIONS

Chronic methotrexate treatment induces a progressive increase in liver stiffness corresponding to mild or moderate perisinusoidal fibrosis for values >9 kPa.

Folate metabolism-related gene polymorphisms and susceptibility to primary liver cancer in North China

Genetic factors may contribute to individual differences in cancer susceptibility. This study was designed to investigate the effects of the polymorphisms of methylenetetrahydrofolate reductase 677 C → T (MTHFR 677 C → T), methylenetetrahydrofolate reductase 1298 A → C (MTHFR 1298A → C), thymidylate synthase (TYMS 3R → 2R), and methionine synthase 2756 A → G (MTR 2756 A → G) on the risk of primary liver cancer (PLC). We conducted a case-control study involving 356 PLC cases and 641 healthy controls in North China. Compared with the MTHFR 677CC genotype, the MTHFR 677TT genotype showed an increased risk for PLC (TT vs. CC: adjusted odds ratio (OR) = 1.56; 95% confidence interval (CI): 1.02-2.40; P = 0.043) after adjusting for gender and age, whereas the MTHFR 1298CC genotype showed a significantly decreased risk for PLC (CC vs. AA: adjusted OR = 0.23; 95% CI: 0.08-0.70; P = 0.010). However, no significant association was found between the TYMS 3R → 2R or the MTR 2756 A → G polymorphism and the risk of PLC. Our results suggest that the MTHFR 677 C → T and the MTHFR 1298A → C genetic polymorphisms might play important role in hepatic carcinogenesis. Further studies with larger sample sizes are required to validate this association.

Hyperhomocysteinemia from trimethylation of hepatic phosphatidylethanolamine during cholesterol cholelithogenesis in inbred mice

Because hyperhomocysteinemia can occur in cholesterol gallstone disease, we hypothesized that this may result from trimethylation of phosphatidylethanolamine (PE), which partakes in biliary phosphatidylcholine (PC) hypersecretion during cholesterol cholelithogenesis. We fed murine strains C57L/J, C57BL/6J, SWR/J, AKR/J, PE N-methyltransferase (PEMT) knockout (KO), PEMT heterozygous (HET), and wildtype (WT) mice a cholesterol/cholic acid lithogenic diet (LD) for up to 56 days and documented biliary lipid phase transitions and secretion rates. We quantified plasma total homocysteine (tHcy), folate, and vitamin B12 in plasma and liver, as well as biliary tHcy and cysteine secretion rates. Rate-limiting enzyme activities of PC synthesis, PEMT and cytidine triphosphate: phosphocholine cytidylyltransferase (PCT), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH) were measured in liver homogenates. Other potential sources of plasma tHcy, glycine N-methyltransferase (GNMT) and guanidinoacetate N-methyltransferase (GAMT), were assayed by gene expression. Plasma tHcy and PEMT activities became elevated during cholelithogenesis in gallstone-susceptible C57L, C57BL/6, and SWR mice but not in the gallstone-resistant AKR mice. Persisting in C57L mice, which exhibit the greatest Lith gene burden, these increases were accompanied by elevated hepatic SAM/SAH ratios and augmented biliary tHcy secretion rates. Counter-regulation included remethylation of Hcy to methionine concurrent with decreased folate and vitamin B12 levels and Hcy transsulfuration to cysteine. Concomitantly, methylenetetrahydrofolate reductase (Mthfr), betaine-homocysteine methyltransferase (Bhmt), and cystathionine-β-synthase (Cbs) were up-regulated, but Gnmt and Gamt genes were down-regulated. PEMT KO and HET mice displayed biliary lipid secretion rates and high gallstone prevalence rates similar to WT mice without any elevation in plasma tHcy levels.

CONCLUSION

This work implicates up-regulation of PC synthesis by the PEMT pathway as a source of elevated plasma and bile tHcy during cholesterol cholelithogenesis.

[Determination of total aminothiols and neuroactive amino acids in plasma by high performance liquid chromatography with fluorescence detection]

This paper describes a simple and sensitive reversed-phase HPLC method for the determination of total homocysteine, total cysteine, total glutathione (GSH+GSSG), and neuroactive amino acids (Asp, Glu, Tau, GABA) using precolumn derivatization with ortho-phtaldialdehyde and fluorimetric detection at 360 and 470 nm for emission and excitation, respectively. Derivatization was performed with ortho-phthaldialdehyde in the presence of 2-mercaptoethanol after alkylation of the free sulfhydryl groups with iodoacetic acid. For determination of total aminothiols, the disulfide bonds were reduced and protein-bound thiols were released by addition of dithiothreitol to the plasma sample. The advantage of this method is the simultaneous determination of both homocysteine/cysteine/glutathione and neuroactive amino acids in the sample. The plasma levels of studied compounds were determined in 14 healthy volunteers (20-45 years old) and 55 patients with chronic hepatitis C (20-49 years old) and the resulting numbers were in a good agreement the studies published earlier. The calibration curves were linear over a concentration range of 5-100 microM in plasma (r2 = 0.985-0.996). The intraday and interday coefficients of variation were 3-6% and 4-7%, respectively. The recovery of the standards added to the plasma samples ranged from 94 to 102%. The limits of detection (LOD) were 0.2-0.5 ng per 10 microl injection volume (signal-to-noise ratio of 3).

Relationship between the MTHFR C677T polymorphism and the outcome of hepatitis B virus infection

AIM: To investigate the relationship between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the outcome of hepatitis B virus (HBV) infection.

METHODS: TaqMan SNP genotyping and sequencing assays were employed to determine the genotypes of MTHFR C677T and the distribution of alleles at this locus in 152 healthy control subjects, 161 self-limited HBV patients, 173 patients with chronic hepatitis B, 138 patients with HBV-induced liver cirrhosis and 181 cases with HBV-related HCC.

RESULTS: Of the 805 subjects, 47.09% had the CT genotype, 30.43% had the TT genotype, and 22.48% had the CC genotype. The frequencies of C and T allele were 46.02% and 53.98%, respectively, which are significantly different from those reported previously. Males with the TT genotype had a reduced risk of liver diseases. The odds ratio (OR) of TT and CT was lowest in the liver cirrhosis group versus the self-limited group (0.675, 95%CI: 0.308-1.479; 0.510, 95%CI: 0.248-1.050). In contrast, females with the TT and CT genotypes had an increased risk of self-limited HBV infection, chronic hepatitis and liver cirrhosis. The liver cirrhosis group had the highest OR value versus the self-limited group (3.542, 95%CI: 0.885-14.171; 3.167, 95% CI: 0.821-12.211; P = 0.022). Females with the TT and CT genotypes had a reduced risk of HCC (OR = 0.638, 95% CI: 0.213-1.904; OR = 0.500, 95%CI: 0.175-1.432).

CONCLUSION: A relatively high frequency of the TT genotype is noted in a Chinese Han population in Tianjin. The MTHFR C677T polymorphism may play a role in influencing disease progression in patients with HBV infection.

The nutrigenetics of hyperhomocysteinemia: quantitative proteomics reveals differences in the methionine cycle enzymes of gene-induced versus diet-induced hyperhomocysteinemia

Hyperhomocysteinemia has long been associated with atherosclerosis and thrombosis and is an independent risk factor for cardiovascular disease. Its causes include both genetic and environmental factors. Although homocysteine is produced in every cell as an intermediate of the methionine cycle, the liver contributes the major portion found in circulation, and fatty liver is a common finding in homocystinuric patients. To understand the spectrum of proteins and associated pathways affected by hyperhomocysteinemia, we analyzed the mouse liver proteome of gene-induced (cystathionine beta-synthase (CBS)) and diet-induced (high methionine) hyperhomocysteinemic mice using two-dimensional difference gel electrophoresis and Ingenuity Pathway Analysis. Nine proteins were identified whose expression was significantly changed by 2-fold (p < or = 0.05) as a result of genotype, 27 proteins were changed as a result of diet, and 14 proteins were changed in response to genotype and diet. Importantly, three enzymes of the methionine cycle were up-regulated. S-Adenosylhomocysteine hydrolase increased in response to genotype and/or diet, whereas glycine N-methyltransferase and betaine-homocysteine methyltransferase only increased in response to diet. The antioxidant proteins peroxiredoxins 1 and 2 increased in wild-type mice fed the high methionine diet but not in the CBS mutants, suggesting a dysregulation in the antioxidant capacity of those animals. Furthermore, thioredoxin 1 decreased in both wild-type and CBS mutants on the diet but not in the mutants fed a control diet. Several urea cycle proteins increased in both diet groups; however, arginase 1 decreased in the CBS(+/-) mice fed the control diet. Pathway analysis identified the retinoid X receptor signaling pathway as the top ranked network associated with the CBS(+/-) genotype, whereas xenobiotic metabolism and the NRF2-mediated oxidative stress response were associated with the high methionine diet. Our results show that hyperhomocysteinemia, whether caused by a genetic mutation or diet, alters the abundance of several liver proteins involved in homocysteine/methionine metabolism, the urea cycle, and antioxidant defense.

Association between the methylenetetrahydrofolate reductase C677T polymorphism and hepatocellular carcinoma risk: a meta-analysis

Background

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the metabolism of folate. The non-synonymous single nucleotide polymorphism (nsSNP), C677T (Ala>Val, rs1801133), has been verified to impair enzyme activity. The association with cancer susceptibility, including hepatocellular carcinoma (HCC), has also been widely studied. The results, however, were inconsistent. To shed light on the influence of MTHFR C677T polymorphism on HCC, a meta-analysis was conducted.

Methods

The meta-analysis of C677T consisted of 10 studies (1814 cases/2862 controls). The association was measured by using random-effect (RE) or fixed-effect (FE) odds ratio (OR) combined with 95% confidence intervals (CIs) according to the studies' heterogeneity.

Results

Using genetic model analysis, C677T polymorphism was found to increase the risk of HCC in a complete overdominant model, which indicates that heterozygotes CT are at a lesser risk of HCC than either homozygotes CC or TT. Meta-analyses of the 10 studies showed that the TT genotype increased the risk of HCC as compared to the CT genotype: FE OR was 1.20 (95%CI: 1.00-1.45, p for heterogeneity = 0.21). When subgroup analysis was done between the HCC cases and the chronic liver disease (CLD) patients of four studies, meta-analysis showed that individuals with the TT genotype had increased HCC risk compared with those with the CT genotype: FE OR (TT vs. CT) reached 1.81 (1.22-2.71, p for heterogeneity = 0.25). Meanwhile, the C677T polymorphism also increased HCC risk in a recessive model when cases were compared to CLD patients of four studies: RE OR reached 1.85 (95%CI: 1.00-3.42, p for heterogeneity = 0.06). Overall, there was some extent heterogeneity when analyses were performed in various models. There was no publication bias.

Conclusion

MTHFR C677T polymorphism increased the risk of HCC in an overdominant model, and might be a risk factor for HCC occurrence, especially in CLD patients. The association warranted further studies.

Homocysteine induces oxidative stress, inflammatory infiltration, fibrosis and reduces glycogen/glycoprotein content in liver of rats

Hyperhomocysteinemia has been related to various diseases, including homocystinuria, neurodegenerative and hepatic diseases. In the present study we initially investigated the effect of chronic homocysteine administration on some parameters of oxidative stress, named total radical-trapping antioxidant potential, total antioxidant reactivity, catalase activity, chemiluminescence, thiobarbituric acid-reactive substances, and total thiol content in liver of rats. We also performed histological analysis, evaluating steatosis, inflammatory infiltration, fibrosis, and glycogen/glycoprotein content in liver tissue sections from hyperhomocysteinemic rats. Finally, we evaluated the activities of aminotransferases in liver and plasma of hyperhomocysteinemic rats. Wistar rats received daily subcutaneous injection of Hcy from their 6th to their 28th day of life. Twelve hours after the last injection the rats were sacrificed, liver and plasma were collected. Hyperhomocysteinemia decreased antioxidant defenses and total thiol content, and increased lipid peroxidation in liver of rats, characterizing a reliable oxidative stress. Histological analysis indicated the presence of inflammatory infiltrate, fibrosis and reduced content of glycogen/glycoprotein in liver tissue sections from hyperhomocysteinemic rats. Aminotransferases activities were not altered by homocysteine. Our data showed a consistent profile of liver injury elicited by homocysteine, which could contribute to explain, at least in part, the mechanisms involved in human liver diseases associated to hyperhomocysteinemia.

Homocysteine levels and sustained virological response to pegylated-interferon alpha2b plus ribavirin therapy for chronic hepatitis C: a prospective study

BACKGROUND

Chronic hepatitis C affects about 3% of the world's population. Pegylated interferon (IFN) alpha plus ribavirin is the gold standard treatment. Methylenetetrahydrofolate reductase(MTHFR) is a key enzyme in the metabolism of homocysteine. MTHFR gene polymorphisms and high levels of homocysteine are associated with a high degree of steatosis and fibrosis, conditions associated with a low sustained virological response (SVR) rate.

AIMS

To evaluate whether MTHFR polymorphisms and homocysteine levels are predictors of the outcome of treatment in 102 prospectively enrolled patients with chronic hepatitis C naive to treatment.

METHODS

Patients were treated with pegylated interferon alpha-2b plus ribavirin. All patients underwent blood tests, assessment of homocysteine, vitamin B(12), folate, hepatitis C virus (HCV)-RNA levels, screening for MTHFR gene polymorphisms and liver ultrasound examination.

RESULTS

Homocysteine levels were deranged (>16 micromol/L) in 10.5% of MTHFR wild-type patients vs 40.3% of non-wild-type patients (P=0.015). Homocysteine levels were 14.4 micromol/L in SVR patients and 15.5 micromol/L in non-SVR patients (P=0.049). The SVR rate was 40.0% in MTHFR wild-type patients, 52.0% in heterozygote mutants and 39.3% in homozygote mutants (P=0.467). At logistic regression analysis, genotypes 2 and 3 (odds ratio: 12.328, 95% confidence interval: 3.390-44.837, P=0.0001), homocysteine <16 micromol/L (odds ratio: 3.397, 95% confidence interval: 1.033-11.177, P=0.044) and aspartate aminotransferase (AST) levels <48 U/L (odds ratio: 3.262, 95% confidence interval: 1.125-9.458, P=0.029) were independent predictors of SVR.

CONCLUSIONS

In patients with chronic hepatitis C, homocysteine levels are associated with the outcome of pegylated-IFNalpha plus ribavirin treatment, while polymorphisms of MTHFR are not.

Measurement of plasma total homocysteine levels in liver failure patients

AIM: To investigate the relationship between plasma total homocysteine (tHcy) levels and liver failure.

METHODS: Plasma tHcy in 96 liver failure patients, 37 non-failure patients and 55 healthy controls were measured by high performance liquid chromatography (HPLC). Serum ALT, AST, TBIL, CHE, ALB, PALB, GLU, Cr and amino acid levels in liver failure patients were also detected, and meanwhile, their relationship with plasma tHcy was analyzed.

RESULTS: The levels of plasma tHcy in liver failure and non-failure patients were significantly higher than those in the healthy controls (14.38 ± 5.85, 12.44 ± 5.39 µmol/L vs 10.29 ± 1.96 µmol/L; P = 0.000, 0.042), and 60.24%, 40.54% of the patients showed significantly higher tHcy levels. Plasma tHcy levels in the acute-on-chronic liver failure patients were a little higher than those in the chronic liver failure patients. There were weak correlations between plasma tHcy levels and ALT, AST, ALB, TBIL, PALB, Cr, and BCAA/AAA, but there was significantly positive correlation between tHcy and methionine (r = 0.297, P < 0.05). The level of tHcy had no marked relation between survivors and the dead.

CONCLUSION: The level of plasma tHcy is obviously elevated in liver failure patients, but it can not be used to evaluate the prognosis of liver failure.

Pharmacogenetic study of methylenetetrahydrofolate reductase and thymidylate synthase in Japanese and assessment of ethnic and gender differences

OBJECTIVES

We investigated the four polymorphisms of the 5,10-methylenetetrahydrofolate reductase (MTHFR) and thymidylate synthase (TYMS) genes that are related to the pharmacologically active sites of methotrexate for the treatment of rheumatoid arthritis in 102 healthy Japanese adults and assessed the possibility of ethnic and gender differences.

METHODS

Polymorphisms of MTHFR C677T, A1298C, the two or three 28-bp tandem repeats in the TYMS 5'-untranslated regions (UTR), and the 6-bp deletion/insertion in the TYMS 3'-UTR were measured using polymerase chain reaction with restriction fragment length polymorphism method. Published data on allelic frequencies by ethnic group and gender were collected from Medline.

RESULTS

Allelic frequencies in healthy Japanese adults were: MTHFR 677T allele 41%, MTHFR 1298C allele 22%, TYMS 5'-UTR 3R allele 84%, and TYMS 3'-UTR-6-bp allele 59%. Significant differences were found in the distribution of MTHFR C677T between black and Japanese populations, of TYMS 5'-UTR alleles between Caucasian or black and Japanese populations, and of TYMS 3'-UTR alleles between Caucasian and Japanese populations (p < 0.001). Moreover, a gender difference was found in TYMS 3'-UTR allelic frequency in Japanese (p = 0.015).

CONCLUSION

Ethnic and gender variations in the distribution of these allelic frequencies may associate with the difference in the effects of methotrexate in rheumatoid arthritis patients.

[Steatosis, chronic hepatitis virus C infection and homocysteine]

Homocysteine, a sulfuric amino acid involved in methionine metabolism, belongs to the group of intracellular thiols. Hyperhomocysteinemia is frequent in the Caucasian population (more than 15%) and its role in vascular pathology has been clearly established. In hepatology, experimental data in transgenic mice deficient in homocysteine metabolism enzymes have shown the presence of severe liver steatosis with occasional steatohepatitis. In human beings, many studies have found a correlation between homocysteine and steatosis or even NASH. Some authors have suggested a discriminating threshold to differentiate simple steatosis from NASH. In chronic hepatitis C, preliminary data have shown that hyperhomocysteinemia is an independent risk factor for steatosis or even fibrosis. The physiopathological mechanism has now begun to be better understood. On one hand, there is a strong correlation between homocysteine and insulin resistance whatever its etiology. On the other hand, homocysteine has a direct effect on the liver, resulting in over expression of SREBP-1 and favouring steatosis. It stimulates proinflammatory cytokine secretion such as NF kappa B increasing the risk of NASH. Finally, homocysteine could increase the risk of fibrosis by stimulating TIMP 1. Moreover hepatitis C virus induces hypomethylation of STAT 1 and could decrease the antiviral activity of interferon. Results from in vitro studies have shown that the normalisation of STAT 1 methylation by bringing betaine and S Adenosyl Methionine (which belongs to homocysteine cycle) restores the antiviral activity of interferon. These data should be confirmed to evaluate the importance of homocysteine dosage in the diagnosis of NASH. Finally, treatment of hyperhomocysteinemia could have favourable consequences in steatopathies and HCV infection.

Methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms and the risk of primary hepatocellular carcinoma (HCC) in a Chinese population

OBJECTIVES

Methylenetetrahydrofolate reductase (MTHFR), which is expressed in the liver, may be involved in both DNA methylation and DNA synthesis. It is also indicated as a potential risk factor of liver cancer in patients with chronic liver disease. To date, no study has been conducted on MTHFR and hepatocellular carcinoma (HCC) using a population-based design. The objective of this study was to evaluate the effects of polymorphisms of the MTHFR gene on the risk of primary liver cancer and their possible effect modifications on various environmental risk factors.

METHODS

A population-based case-control study was conducted in Taixing, China. MTHFR C677T and A1298C were assayed by PCR-RFLP techniques.

RESULTS

The frequency of MTHFR 677 C/C wild homozygotes genotype was 25.8% in cases, which was lower than that in controls (34.5%). The adjusted odds ratios (ORs) for the MTHFR 677 C/T and T/T genotype were 1.66(95% CI: 1.06-2.61), 1.21(95% CI: 0.65-2.28) respectively when compared with the MTHFR 677 C/C genotype. Subjects carrying any T genotype have the increased risk of 1.55(95% CI: 1.01-2.40) for development of primary hepatocellular carcinoma. A high degree of linkage disequilibrium was observed between the C677T and A1298C polymorphisms, with the D' of 0.887 and p < 0.01. The MTHFR 677 any T genotype was suggested to have potentially more than multiplicative interactions with raw water drinking with p-value for adjusted interaction of 0.03.

CONCLUSION

We observed that the MTHFR 677 C/T genotype was associated with an increased risk of primary liver cancer in a Chinese population. The polymorphism of MTHFR 677 might modify the effects of raw water drinking on the risk of primary hepatocellular carcinoma.