Hyperhomocysteinemia and the MTHFR C677T polymorphism promote steatosis and fibrosis in chronic hepatitis C patients

The factors and mechanisms implicated in the development of hepatitis C virus (HCV)-related steatosis are unknown. Hyperhomocysteinemia causes steatosis, and the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism induces hyperhomocysteinemia. We investigated the role of these factors in the development of HCV-related steatosis and in the progression of chronic hepatitis C (CHC). One hundred sixteen CHC patients were evaluated for HAI, fibrosis and steatosis grades, body mass index, HCV genotypes, HCV RNA levels, homocysteinemia, and the MTHFR C677T polymorphism. Hyperhomocysteinemia was associated with the TT genotype of MTHFR (r = 0.367; P = .001). Median values of homocysteine in the CC, CT, and TT genotypes of the MTHFR gene were 9.3, 12.2, and 18.6 micromol/L, respectively (P = .006). Steatosis correlated with the MTHFR polymorphism, homocysteinemia, HAI and fibrosis. Steatosis above 20% was significantly associated with fibrosis. Prevalence and high grade (>20%) of steatosis were 41% and 11% in CC, 61% and 49% in CT, and 79% and 64% in TT, respectively (P = .01). Relative risk of developing high levels of steatosis was 20 times higher for TT genotypes than CC genotypes. According to multivariate analysis, steatosis was independently associated with hyperhomocysteinemia (OR = 7.1), HAI (OR = 3.8), liver fibrosis (OR = 4.0), and HCV genotype 3 (OR = 4.6). On univariate analysis, fibrosis was associated with age, steatosis, MTHFR, homocysteinemia and HAI; however, on multivariate analysis, liver fibrosis was independently associated with age (P = .03), HAI (P = .0001), and steatosis (P = .007). In conclusion, a genetic background such as the MTHFR C677T polymorphism responsible for hyperhomocysteinemia plays a role in the development of higher degree of steatosis, which in turn accelerates the progression of liver fibrosis in CHC.     

MTHFR C677T polymorphism: association with lymphoid neoplasm and effect on methotrexate therapy

The aim of this study was to detect the possible role of methylene tetrahydrofolate reductase gene polymorphism (MTHFR C677T) in the pathogenesis of lymphoid neoplasms and to investigate the influence of this polymorphism on methotrexate toxicity in adult ALL patients treated with methotrexate maintenance therapy. There was a statistically significant increase in the risk of non‐Hodgkin lymphoma in patients with CT genotype (OR, 2.9; 95% CI, 1.3–6.3; P = 0.007) and combined CT + TT genotype (OR, 3.2; 95% CI, 1.5–6.6; P = 0.006). While no significant association was found between this polymorphism and ALL risk. The patients with ALL treated with methotrexate during maintenance therapy were observed for signs of toxicity. MTHFR 677C>T polymorphism (CT + TT) was significantly overrepresented among cases with hepatic toxicity (OR = 15.6; 95% CI, 2.6–81.3; P = 0.001). In addition, they were overrepresented among cases with mucositis, anemia, thrombocytopenia, and leukopenia. However, it did not reach statistical significance level. Further studies on larger number of subjects are necessary. Additional studies on the role of MTHFR gene polymorphism with environment (folate intake) interaction are needed to confirm the role of these genetic polymorphisms.     

Abdominal fat interacts with PNPLA3 I148M,but not with the APOC3 variant in the pathogenesis of liver steatosis in chronic hepatitis C

The patatin‐like phospholipase domain‐containing 3 gene (PNPLA3) and the apolipoprotein C3 gene (APOC3) have been studied in relation to liver steatosis and liver disease outcome. The aim of this study was to evaluate the influence of PNPLA3 p.I148M and APOC3 rs2854116 and rs2854117 polymorphisms on the clinical and histological presentation of chronic hepatitis C in an Italian population and their relationship with viral and anthropometric parameters. Patients with hepatitis C (n = 166) entered the study receiving a clinical, histological, virological and biochemical evaluation. APOC3 (rs2854116 and rs2854117) and PNPLA3 (p.I148M) variants were genotyped. PNPLA3 polymorphisms were associated with liver steatosis, which was significantly higher in patients with p.148I/M (P = 0.034) and p.148M/M (P = 0.004) variants than those homozygous for the PNPLA3 wild type. Excluding patients with HCV genotype 3, the association with liver steatosis and PNPLA3 variants was more marked (p.148I/I genotype vs p.148I/M, P = 0.02, and vs p.148M/M, P = 0.005). The APOC3 polymorphism was not associated with any of the evaluated parameters. Among the interacting factors, BMI and waist circumference correlated with liver steatosis (P = 0.008 and 0.004, respectively). Relationship between waist circumference and liver steatosis was analysed for the different PNPLA3 genotypes. Homozygous 148M patients showed a stronger correlation between waist circumference and steatosis than those carrying the other genotypes (P = 0.0047). In our hepatitis C‐infected population, the PNPLA3 polymorphism influenced the development of liver steatosis, but not fibrosis progression. APOC3 polymorphisms had no effect on the development of steatosis and no influence on the PNPLA3 polymorphism. The amount of abdominal fat can increase the association of PNPLA3 p.I148M with liver steatosis.     

Homocysteine and methylenetetrahydrofolate reductase C677T and A1298C polymorphisms in Tunisian patients with severe coronary artery disease

Elevation in homocysteine and methylenetetrahydrofolate reductase (MTHFR) gene variants, C677T and A1298C, have been linked with atherothrombosis. However their exact contribution to coronary artery disease (CAD) remains controversial. Moreover, data from Tunisian patients are scarse. We examined the association of MTHFR C677T and A1298C, and changes in plasma homocysteine in 352 Tunisian patients with angiographically-demonstrated CAD, and 390 age and gender-matched healthy subjects. Significantly higher frequency of 677T allele and homozygous 677T/T genotype were seen in patients vs. control subjects; the distribution of A1298C alleles and genotypes being comparable in the two groups. Specific MTHFR haplotypes comprising 677C/1298A (P < 0.001) and 677T/1298A (P < 0.001) were negatively and positively associated with CAD, respectively. Plasma homocysteine concentration was significantly higher in 677T/T genotype with respect to 677C/C and 677C/T genotypes in patients and controls, but homocysteine levels were generally comparable between both groups. Univariate analysis identified 677T/1298A (P = 0.033) haplotype to be positively associated with CAD, which remained significant by multivariate analysis after adjusting for a number of covariates (P = 0.038). MTHFR C677T, but not A1298C SNPs, is associated with CAD and with elevated homocysteine levels in a Tunisian population. The negative and positive association of the 1298A allele with CAD being indicative of a neutral (absent) effect of the A1298C SNP on disease pathogenesis.     

PNPLA3 as a liver steatosis risk factor following living‐donor liver transplantation for hepatitis C

Aim

Liver steatosis frequently occurs following liver transplantation (LT) and can affect patient outcome. Here, we aimed to clarify the steatosis and steatohepatitis risk factors that apply after living‐donor LT for chronic hepatitis C.

Methods

We retrospectively examined 43 transplant recipients and donors, and tested for single nucleotide polymorphisms in the PNPLA3 gene. Liver biopsies taken 1 year after transplantation and yearly thereafter, or when abnormal liver enzyme levels were detected, were examined by histopathology.

Results

Liver steatosis (>5% steatotic hepatocytes) was evident in 13 of 43 cases (30%), and steatohepatitis in 3 (7.0%). The average time to steatosis after LT was 2.74 ± 1.55 years. The PNPLA3 rs738409 GG genotype, a steatosis risk factor, was identified in 13 recipients and 10 donors. Steatosis prevalence did not differ according to recipient genotype. However, this condition was significantly more common among patients who received tissue from donors carrying the rs738409 GG genotype compared to those with grafts from donors of the CC or CG genotype (60, 7, and 26%, respectively; P < 0.05). All 3 steatohepatitis cases were associated with the GG donor genotype.

Conclusion

The PNPLA3 rs738409 GG donor genotype affects liver steatosis and steatohepatitis risk following living‐donor LT.     

Associations of methylenetetrahydrofolate reductase C677T genotype with blood pressure levels in Chinese population with essential hypertension

Objective: To confirm the association between baseline blood pressure (BP) levels and the methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism in patients with essential hypertension. Methods: A total of 347 patients were enrolled from the Dongzhi community in Anhui Province, China. The C677T polymorphism of the MTHFR gene was detected using high-throughput TaqMan allelic discrimination assay. Baseline BP was measured using a standardized mercury-gravity monometer. Results: In the whole sample, the frequency of the MTHFR C677T genotypes CC, CT, and TT were 38.6%, 48.1%, and 13.3%, respectively. In a recessive model (CC+CT versus TT genotypes), baseline diastolic blood pressure (DBP) was significantly higher in patients with the TT genotype compared to those with the CT or CC genotypes (P= 0.013). We also divided all patients into three groups based on the tertiles of the baseline BP distribution. Compared to subjects in the lowest tertile of DBP, the adjusted odds of having the TT genotype among subjects in the highest tertile was 2.6 (95% CI: 1.1 to 6.2). However, no significant associations were observed between baseline systolic blood pressure (SBP) and the MTHFR C677T polymorphism. Conclusions: The MTHFR gene polymorphism could be an important genetic determinant of baseline DBP levels in Chinese essential hypertensive patients.     

Hyperhomocysteinemia and the methylene tetrahydrofolate reductase C677T mutation in splanchnic vein thrombosis

Introduction: The role that hyperhomocysteinemia (HH) and the C677T mutation in 5,10‐methylenetetrahydrofolate reductase (MTHFR) play in splanchnic vein thrombosis (SVT) remains unclear due to this unusual thrombotic location. Objective: To analyse the possible association of HH with the C677T mutation in the MTHFR gene in SVT. Material and methods: We determined homocysteine levels and the C677T MTHFR mutation, along with classical cardiovascular risk factors, in 48 patients with SVT (18 Budd‐Chiari syndrome, 11 mesenteric vein thrombosis, 19 portal vein thrombosis) and 84 controls. Results: In the univariate analysis, patients with SVT showed statistically higher homocysteine levels (P = 0.044). After adjusting for total cholesterol, differences disappeared (P = 0.256). However, no differences in homocysteine levels were observed when comparing the three SVT types (P = 0.199), even after adjusting for age and total cholesterol (P = 0.095). In addition, the prevalence of the TT genotype was no different when controls were compared with patients with SVT (P = 0.253) or with SVT subtypes (P = 0.885). No association was found between HH (>15 μm ) and the TT genotype in cases (P = 0.404), controls (P = 0.178), or in the different SVT subtypes (P = 0.495). Conclusions: Our results suggest that HH and the homozygous genotype in the MTHFR C677T mutation do not seem to play a role in SVT development.     

Relationship between genetic polymorphism of MTHFR C677T and lower extremities deep venous thrombosis

Objective: To investigate the association between the polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene and the formation of lower extremities deep venous thrombosis, and to evaluate the etiology of deep venous thrombosis.

Methods: Polymorphisms of the 677th site C/T in MTHFR gene for 101 patients with lower extremities deep venous thrombosis (DVT group) and 120 healthy subjects (control group) were detected by polymerase chain reaction with sequence-specific primers. Genotype and allelic frequencies were compared between the two groups.

Results: Genotype frequencies of CC, CT and TT in MTHFR C677?T were 41.58, 25.74 and 32.67% in DVT group, and 58.33, 23.33 and 18.33% in control group, respectively. There was a significant difference in TT genotype frequency between the two groups (P <0.05).

Conclusion: The frequency of MTHFR 677TT genotype may be correlated with the morbility of DVT.     

Sex-related influence of angiotensin-converting enzyme polymorphisms on fibrosis progression due to recurrent hepatitis C after liver transplantation

Background Experimental evidence and clinical studies suggest that the renin–angiotensin system and its inhibitors may play a role in regulating the mechanisms of liver fibrosis development. The present study aimed to verify whether carriage of specific angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) allelic variants, modulating angiotensin II generation, could affect the outcome of recurrent hepatitis C after liver transplantation, via several metabolic pathways. Methods Forty-five (29 men) recipients, with a median histological follow-up of 60 months after orthotopic liver transplantation (OLT), were studied. ACE gene I/D polymorphism was assessed by means of a polymerase chain reaction procedure. Fibrosis progression was evaluated annually during the follow-up. Results Weight gain 1 year post-OLT (defined as an increase in body mass index, BMI, of >0.5 kg/m²) was significantly more common among D/* carriers (22/22 vs. 16/23, P < 0.005); patients who 1 year after OLT had an increase in their BMI value of >0.5 kg/m² more frequently had a triglycerides/cholesterol ratio of ≤ 0.7 (16/22 vs. 8/23, χ-squared test P < 0.02). This association was stronger in men. Female D/D homozygotes had the highest probability of showing significant liver fibrosis (7/10) in comparison with men (11/29) and I/* women (1/6) (P < 0.01). Conclusions In patients with recurrent hepatitis C, carriers of the D allele appeared to gain more weight after liver transplantation, and in male liver recipients, the D allele was associated with a peculiar lipid profile that was associated with a slower rate of allograft fibrosis progression. Among female recipients, carriage of the D allele may favor more severe allograft fibrosis.     

Microsomal triglyceride transfer protein polymorphism (−493G/T) is associated with hepatic steatosis in patients with chronic hepatitis C

Background: Hepatic steatosis may promote progression of chronic hepatitis C (CHC). Microsomal triglyceride transfer protein (MTP) is required for assembly and secretion of ApoB lipoprotein and is implicated in hepatitis C virus (HCV)‐related steatosis. The MTP ?493G/T polymorphism may promote liver fat accumulation, but its role in HCV‐related steatosis is still unclear. Methods: Two hundred ninety‐eight CHC patients were studied and genotyped for MTP ?493G/T variants. Hepatic MTP mRNA expression and activity were determined in a subgroup. Results: Patients with grades 2/3 steatosis were older, had a higher body mass index (BMI), more advanced fibrosis and lower MTP mRNA expression and carried more often HCV genotype 3 and the MTP T allele. Age, BMI, HCV‐3 and MTP T allele [odds ratio (OR) 2.05; 95% confidence interval (CI) 1.2–3.53; P=0.009] were independent risk factors for steatosis grades 2/3, and in HCV genotype non‐3 patients, the MTP T allele was the strongest predictor for steatosis grade 2/3 (OR 2.17; 95% CI 1.22–3.86; P=0.008). Moreover, TT carriers had higher high‐density lipoprotein (65.6±14.6 vs 56.1±16.2 mg/dl; P=0.003) and apolipoprotein AI (1.80±0.3 vs 1.60±0.3 g/L; P=0.005) levels than G allele carriers. Conclusions: Chronic hepatitis C patients with the MTP ?493T allele reveal higher grades of steatosis, indicating a relevant contribution to liver fat accumulation, particularly in HCV non‐3 patients.     

Analysis of thrombophilic genetic mutations in patients with Sheehan`s syndrome: is thrombophilia responsible for the pathogenesis of Sheehan`s syndrome?

The gene mutations of Factor V R506Q (FV-Leiden), prothrombin (FII G20210A), methylene tetrahydrofolate reductase (MTHFR) C677T and A1298C and PAI-1 4G/5G are well-established risk factors for thrombosis. We aimed to investigate the prevalence of these gene mutations and their possible impact on the development of pathogenesis in patients with Sheehan’s syndrome (SS). 40 female patients with SS compared to a control group of 45 healthy women. The presence of FV-Leiden, FII G20210A, MTHFR C677T, MTHFR A1298C and PAI-1 4G/5G gene mutations were assessed by polymerase chain reaction analysis with a light cycler analyzer. An odds ratio of greater than one is considered to increase the risk of SS disease as found in Factor V Leiden, FII G20210A, MTHFR C677T, MTHFR A1298C and PAI-1 4G/5G polymorphism, as follows respectively: 1.13, 1.85, 6.00, 8.14 and 1.45. MTHFR C677T and MTHFR A1298C polymorphism were found significantly higher in SS patients than the control group (P < 0.001), however FV-Leiden, FII G20210A and PAI-1 4G/5G polymorphism showed no significant difference (P > 0.05). The level of plasma total homocysteine (tHcy) was significantly higher in patients with SS than in the control group (P < 0.001). We suggest that the genetic mutations of FV-Leiden, FII G20210A, MTHFR C677T, MTHFR A1298C and PAI-1 4G/5G increase the risk of SS. Also, high plasma tHcy levels may be a risk factor for the development of SS.     

Mild hyperhomocysteinemia,C677T polymorphism on methylenetetrahydrofolate reductase gene and the risk of macroangiopathy in type 2 diabetes: a prospective study

The role of hyperhomocysteinemia as a risk factor for diabetic long-term complications has not been sufficiently evaluated in prospective studies, considering specific correlates of homocysteine (tHcy) concentration and traditional cardiovascular disease (CVD) risk factors. Fasting tHcy, vitamin B12 and folate plasma levels, the common methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism, as well as clinical and lifestyle information were assessed in 216 type 2 diabetic patients attending two outpatient clinics, who had a follow-up evaluation at 65 ± 9 months for the incidence of macroangiopathy. At basal evaluation, mild hyperhomocysteinemia (tHcy ≥ 15 μmol/l) was diagnosed in 21.3% of participants. At follow-up, hyperhomocysteinemia and the distribution of MTHFR C677T genotype did not significantly differ according to the incidence of macroangiopathy. Multiple variables adjusted ORs (95% CI) for CVD associated with mild hyperhomocysteinemia were 1.01 (0.37–2.82); P > 0.05; those associated with MTHFR TT genotype were 0.46 (0.15–1.38); P > 0.05. Although the prevalence of hyperhomocysteinemia was higher in diabetic men (26.9%) than in women (16.1%; P > 0.05), similar results were also observed in a separate sex-analysis. At the multivariate analysis, including in the model other potential CVD risk factors, only creatinine clearance was a significant risk factor for the development of macroangiopathy. In this cohort of diabetic subjects, mild hyperhomocysteinemia and the MTHFR TT genotype are not significant risk factors for the development of macroangiopathy; impaired renal function was confirmed as a significant predictor of this complication.     

Methylenetetrahydrofolate reductase C677T polymorphism and predisposition towards esophageal squamous cell carcinoma in a German Caucasian and a northern Chinese population

Purpose Folate deficiency is considered to increase the risk of developing esophageal cancer. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme involved in folate metabolism. A single C T substitution at nucleotide 677 of the MTHFR cDNA influences enzyme activity. The purpose of this study is to compare the association of the MTHFR C677T polymorphism with susceptibility to esophageal squamous cell carcinoma (ESCC).Methods Using real-time PCR and melting curve analysis, the MTHFR C677T genotypes were determined in 430 patients with ESCC (241 German Caucasians and 189 northern Chinese) and 397 unrelated healthy controls (256 German Caucasians and 141 northern Chinese).Results A significant difference in MTHFR C677T genotype distribution was observed between German Caucasian controls (C/C, 41.8%, C/T, 44.9%, T/T, 13.3%) and northern Chinese controls (C/C, 17.7%, C/T, 38.3%, T/T, 44.0%) (²=52.19, P<0.001). The distribution of the MTHFR C677T genotypes among German ESCC patients (C/C, 39.0%, C/T, 48.1%, T/T, 12.9%) was not significantly different from that among healthy controls (²=0.531, P=0.767). In contrast, the frequency of the C/C genotype among Chinese ESCC patients (8.5%) was significantly lower than among Chinese healthy controls (17.7%) (²=6.37, P=0.012). The C/C genotype was correlated with a significantly reduced risk for the development of ESCC as compared to the combination of C/T and T/T genotypes (adjusted OR=0.38, 95% CI=0.16–0.88).Conclusions Our results suggest that, in contrast to German Caucasians, the MTHFR 677CC homozygous wild-type plays a protective role in the development of ESCC in the northern Chinese population.Abbreviations CI Confidence interval - ESCC Esophageal squamous cell carcinoma - MTHFR Methylenetetrahydrofolate reductase - OR Odds ratio - PCR Polymerase chain reaction     

Matrix metalloproteinase 2 genotype is associated with nonanastomotic biliary strictures after orthotopic liver transplantation

Background: Nonanastomotic biliary strictures (NAS) are a serious complication after orthotopic liver transplantation (OLT). Matrix metalloproteinases (MMPs) are involved in connective tissue remodelling in chronic liver disease and complications after OLT. Aim: To evaluate the relationship between MMP‐2 and MMP‐9 gene polymorphisms and NAS. Methods: MMP‐2 (?1306 C/T) and MMP‐9 (?1562 C/T) gene promoter polymorphisms were analysed in 314 recipient–donor combinations. Serum levels of these MMPs were determined in subgroups of patients as well. NAS were identified with various radiological imaging studies performed within 4 years after OLT and defined as any stricture, dilation or irregularity of the intra‐ or extrahepatic bile ducts of the liver graft followed by an intervention, after exclusion of hepatic artery thrombosis and anastomotic strictures. Results: The average incidence of NAS was 15%. The major clinical risk factor for the development of NAS was PSC in the recipient. The presence of the MMP‐2 CT genotype in donor and/or recipient was associated with a significantly higher incidence of NAS, up to 29% when both donor and recipient had the MMP‐2 CT genotype (P=0.003). In the multivariate analyses, pre‐OLT PSC (hazard ratio 2.1, P=0.02) and MMP‐2 CT genotype (hazard ratio 3.5, P=0.003) were found to be independent risk factors for the development of NAS after OLT. No obvious association was found between NAS and the MMP‐9 genotype and serum levels of the MMPs. Conclusion: MMP‐2 CT genotype of donor and recipient is an independent risk factor, in addition to PSC, for the development of NAS after OLT.     

Methylenetetrahydrofolate reductase (MTHFR) C677T genetic polymorphism and late infarct-related coronary artery patency after thrombolysis

In patients with acute myocardial infarction (AMI), a persistently occluded infarct-related artery (IRA) is associated with unfavorable prognosis and genetic factors may be contributing factors to thrombolysis failure. One-hundred and one consecutive patients treated with intravenous thrombolysis during AMI were blind-tested for methylenetetrahydrofolate reductase (MTHFR) and circulating homocysteine levels and underwent protocol angiography 14 ± 6 days after the event. IRA was patent in 61 patients and occluded in 40. Overall MTHFR 677TT frequency was 22%. Patients with MTHFR 677TT homozygosis had higher prevalence of occluded IRA (73%) versus those with MTHFR 677CT/CC genotype (30%, P < 0.001); MTHFR 677TT genotype predicted independently the risk of IRA occlusion with a specificity of 90% (odds ratio 3.8, 95% confidence interval 1.1–9.1; P = 0.03). Moreover, patients with occluded IRA and MTHFR 677TT genotype had the highest homocysteine levels (21 ± 7.6 μmol/l vs. ≤14.9 ± 3.8 μmol/l; P = 0.011). In patients with AMI, MTHFR 677TT homozygosis is independently associated with a persistently occluded IRA after thrombolysis. This finding may have pathophysiological and therapeutic implications for recanalization strategies in patients with AMI.     

Cytokine gene polymorphisms and the susceptibility to liver cirrhosis in patients with chronic hepatitis C

Background: The speed of fibrosis progression varies considerably between patients with chronic hepatitis C. This study analyzed whether cytokine gene polymorphisms are associated with a progressive course of the disease. Methods: Leukocyte DNA from 101 patients with chronic hepatitis C, 52 patients with hepatitis C virus (HCV)‐induced cirrhosis and 200 Caucasian blood donors was prepared. Using PCR, RFLP and PAGE, gene polymorphism analysis of the interleukin (IL)1α(?889), IL1β(?511 and +3954), IL1 receptor agonist (RA)(intron2 VNTR), IL4(intron3 VNTR) and TNFα(?308) loci was performed. Results: Of the polymorphisms analyzed, IL1β(?511) and IL1RA(intron2 VNTR) were unevenly distributed between the study groups. The IL1β(?511)^*A2A2 genotype occurred significantly more often in chronic hepatitis C and HCV‐induced liver cirrhosis than in the controls (P<0.01, P<0.05, respectively). Patients with HCV‐induced cirrhosis displayed a significantly higher frequency of the IL1RA(intron2 VNTR)^*A2 polymorphism than patients with chronic hepatitis C and controls (P<0.05). Conclusions: Although the IL1β(?511)^*A2A2 genotype may increase the susceptibility to acquire chronic hepatitis C and IL1RA(intron2 VNTR)^*A2 polymorphism is associated with disease progression to cirrhosis, our results indicate that the analyzed cytokine gene polymorphisms have an overall low impact on the natural course of chronic hepatitis C infection.     

Lack of association between the MTHFR (C677T) polymorphism and atopic disease

Background: Impaired folate metabolism has been suggested as a potential risk factor for the development of asthma and atopic disease. However, there have been conflicting reports on the potential association between atopic disease and a common polymorphism of the methylene‐tetrahydrofolate reductase (MTHFR)‐gene, a well‐known marker of impaired folate metabolism. Objectives: The aim of this study was to investigate the association between the MTHFR (C677T) polymorphism and different outcome variables of asthma and atopic disease. Methods: This study was a population‐based study of 1189 participants aged 15–77 years living in Copenhagen, the Capital of Denmark. Examinations included measurements of specific IgE and skin prick tests against inhalant allergens, metacholine bronchial hyper‐reactivity, and serum eosinophilic cationic protein, and a self‐administered questionnaire about diagnoses and symptoms of allergy and asthma. In addition, participants were genotyped for the MTHFR (C677T) polymorphism. Results: None of the examined outcomes were significantly associated with the MTHFR (C677T) polymorphism. Conclusions: The results of this study using detailed objective markers of atopic disease do not support the hypothesis that impaired folate metabolism as reflected by the MTHFR genotype is involved in the development of atopic disease. Please cite this paper as: Thuesen BH, Husemoen LLN, Fenger M and Linneberg A. Lack of association between the MTHFR (C677T) polymorphism and atopic disease. The Clinical Respiratory Journal 2009; 3: 102–108.     

Association of Methylenetetrahydrofolate Reductase Gene 677C>T Polymorphism with Hypertension in Older Women in a Population of Buenos Aires City

We examined the relationship between the 677C >T polymorphism in the MTHFR gene and tHcy in normotensive (NT) and hypertensive (HT) subjects and the influence of sex and age in a cross-sectional study. Smoking habits, history of vascular disease, diabetes, and tHcy were significantly associated with T allele as hypertension risk factors. The T allele was significantly related with higher tHcy in (i) men versus women (P < .01), (ii) men and women older than 47 years versus the younger ones (P < .05 and P < .001, respectively), (iii) HT women versus NT women (P < .01), and (iv) older HT women versus older NT women (P < .01). We found an association between the 677C>T MTHFR polymorphism and tHcy with hypertension that in women is manifested with age.     

Connective tissue growth factor,steatosis and fibrosis in patients with chronic hepatitis C

Background/Aim: Both steatosis and insulin resistance have been linked to accelerated fibrosis in chronic hepatitis C. Connective tissue growth factor (CTGF) plays a major role in extracellular matrix production in fibrotic disorders including cirrhosis, and its expression is stimulated in vitro by insulin and glucose. We hypothesized that CTGF may link steatosis, insulin resistance and fibrosis. Methods: We included 153 chronic hepatitis C patients enrolled in the Swiss Hepatitis C Cohort Study and for whom a liver biopsy and plasma samples were available. CTGF expression was assessed quantitatively by immunohistochemistry. In 94 patients (57 with genotypes non‐3), plasma levels of glucose, insulin and leptin were also measured. CTGF synthesis was investigated by immunoblotting on LX‐2 stellate cells. Results: Connective tissue growth factor expression was higher in patients with steatosis (P=0.039) and in patients with fibrosis (P=0.008) than those without these features. CTGF levels were neither associated with insulinaemia or with glycaemia, nor with inflammation. By multiple regression analysis, CTGF levels were independently associated with steatosis, a past history of alcohol abuse, plasma leptin and HCV RNA levels; when only patients with genotypes non‐3 were considered, CTGF levels were independently associated with a past history of alcohol abuse, plasma leptin levels and steatosis. Leptin stimulated CTGF synthesis in LX‐2 cells. Conclusions: In patients with chronic hepatitis C and steatosis, CTGF may promote fibrosis independently of inflammation. CTGF may link steatosis and fibrosis via increased leptin levels.