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.     

Activation of factor XI in plasma is dependent on factor XII [see comments]

The activation of factor XI initiates the intrinsic coagulation pathway. Until recently it was believed that the main activator of factor XI is factor XIIa in conjunction with the cofactor high molecular weight kininogen on a negatively charged surface. Two recent reports have presented evidence that in a purified system factor XI is activatable by thrombin together with the soluble polyanion dextran sulfate. To assess the physiological relevance of these findings we studied the activation of factor XI in normal and factor XII-deficient plasma. We used either kaolin/cephalin or dextran sulfate as a surface for the intrinsic coagulation pathway, tissue factor to generate thrombin via the extrinsic pathway, or the addition of alpha-thrombin directly. 125I-factor XI, added to factor XI-deficient plasma at physiologic concentrations (35 nmol/L), is rapidly cleaved on incubation with kaolin. The kinetics appear to be exponential with half the maximum cleavage at 5 minutes. Similar kinetics of factor XI cleavage are seen when 40 nmol/L factor XIIa (equal to 10% of factor XII activation) is added to factor XII-deficient plasma if an activating surface is provided. Tissue factor (1:500) added to plasma did not induce cleavage of factor XI during a 90-minute incubation, although fibrin formation within 30 seconds indicated that thrombin was generated via the extrinsic pathway. Adding 1 mumol/L alpha-thrombin (equivalent to 50% prothrombin activation) directly to factor XII deficient or normal plasma (with or without kaolin/cephalin/Ca2+ or dextran sulfate) led to instantaneous fibrinogen cleavage, but again no cleavage of factor XI was observable. We conclude that in plasma surroundings factor XI is not activated by thrombin, and that proposals of thrombin initiation of the intrinsic coagulation cascade are not supportable.     

The TTTT B lymphocyte stimulator promoter haplotype is associated with good response to rituximab therapy in seropositive rheumatoid arthritis resistant to tumor necrosis factor blockers

Objective

To investigate the polymorphisms in the promoter region of the B lymphocyte stimulator (BLyS) gene as markers of response to rituximab (RTX) in rheumatoid arthritis (RA).

Methods

The study was first conducted in 152 Italian RA patients and then replicated in an additional 117 RA patients (73 Italian, 44 British). The European League Against Rheumatism response criteria were used to evaluate the response rate at months 4 and 6 after the first cycle of RTX, by means of the Disease Activity Score in 28 joints using the erythrocyte sedimentation rate; patients were classified according to the best response shown between months 4 and 6. BLyS promoter polymorphisms were analyzed by polymerase chain reaction followed by the analysis of the restriction fragments, BLyS promoter haplotypes were analyzed using the expectation‐maximization algorithm, and BLyS serum levels were analyzed using enzyme‐linked immunosorbent assay. Odds ratios (ORs) were calculated with 95% confidence intervals (95% CIs).

Results

The TTTT BLyS promoter haplotype appeared to be significantly associated with response to RTX only in the subset of seropositive patients (those positive for rheumatoid factor and/or anti–cyclic citrullinated peptide). The replication study confirmed that this association was limited to seropositive RA patients in whom treatment with anti–tumor necrosis factor (anti‐TNF) agents had previously failed. In the whole series of seropositive patients in whom anti‐TNF agents had previously failed, patients carrying the TTTT BLyS promoter haplotype were more prevalent in good responders (18 of 43 [41.9%]) than in moderate responders (20 of 83 [24.1%]) or in nonresponders (1 of 21 [4.8%]) (for good responders versus nonresponders, OR 14.4 [95% CI 1.77–117.39], P = 0.0028). Furthermore, multivariate analysis selected the TTTT BLyS promoter haplotype as an independent marker of good response to RTX (for good responders versus nonresponders, OR 16.2 [95% CI 1.7–152.5], P = 0.01; for good responders versus moderate responders and nonresponders combined, OR 3.1 [95% CI 1.2–7.8], P = 0.02). The relationship between BLyS polymorphisms and BLyS serum levels remained unclear.

Conclusion

BLyS promoter genotyping may be suitable for identifying seropositive RA patients who may have a good response to RTX after anti‐TNF agents have failed.

     

Colonic preparation before colonoscopy in constipated and non-constipated patients:A randomized study

AIM: To compare the efficacy of different doses of sodium phosphate(NaP) and polyethylenglicol(PEG) alone or with bisacodyl for colonic cleansing in constipated and non-constipated patients.METHODS: Three hundred and forty-nine patients,older than 18 years old,with low risk for renal damage and who were scheduled for outpatient colonoscopy were randomized to receive one of the following preparations(prep): 90 mL of NaP(prep 1);45 mL of NaP + 20 mg of bisacodyl(prep 2);4 L of PEG(prep 3) or 2 L of PEG + 20 mg of bisacodyl(prep 4).Randomization was stratified by constipation.Patients,endoscopists,endoscopists’ assistants and data analysts were blinded.A blinding challenge was performed to endoscopist in order to reassure blinding.The primary outcome was the efficacy of colonic cleansing using a previous reported scale.Secondary outcomes were tolerability,compliance,side effects,endoscopist perception about the necessity to repeat the study due to an inadequate colonic preparation and patient overall perceptions.RESULTS: Information about the primary outcome was obtained from 324 patients(93%).There were no significant differences regarding the preparation quality among different groups in the overall analysis.Compliance was higher in the NaP preparations being even higher in half-dose with bisacodyl: 94%(prep 1),100%(prep 2),81%(prep 3) and 87%(prep 4)(2 vs 1,3 and 4,P < 0.01;1 vs 3,4,P < 0.05).The combination of bisacodyl with NaP was associated with insomnia(P = 0.04).In non-constipated patients the preparation quality was also similar between different groups,but endoscopist appraisal about the need to repeat the study was more frequent in the half-dose PEG plus bisacodyl than in whole dose NaP preparation: 11%(prep 4) vs 2%(prep 1)(P < 0.05).Compliance in this group was also higher with the NaP preparations: 95%(prep 1),100%(prep2) vs 80%(prep 3)(P < 0.05).Bisacodyl was associated with abdominal pain: 13%(prep 1),31%(prep 2),21%(prep 3) and 29%(prep 4),(2,4 vs 1,2,P < 0.05).In constipated pati     

A 17-year-old with rash, fever, myalgias, and nephritis

Patients on hemodialysis are at increased risk for developing active tuberculosis (TB) after primary infection. Although this increased risk is well documented, the prevalence of TB infection, as indicated by a positive tuberculin skin test (TST), is not well described. End-stage renal disease is also known to be a risk factor for skin test anergy, but the rate of anergy in hemodialysis patients is unclear. We sought to identify rates of anergy and TST positivity in patients at four hemodialysis units in St Louis, Missouri, from June 1996 through August 1996. Data obtained from patients and medical records included age, years on hemodialysis, medical history, and basic laboratory data. Patients without a history of TB or a positive TST had a TST with Tubersol, as well as candida and tetanus controls, placed by the Mantoux method. Tests were read 48 hours later. Of the patients enrolled at these units, 307 of 331 (93%) were evaluated. Patients had a mean age of 58 years (range, 19 to 91 years) and had been on hemodialysis for a mean of 3.7 years (range, 1 week to 18.7 years). Blacks made up 81% of the population. A history of a positive TST was obtained from 24 patients (8%), and an additional seven (2%) had a history of active TB. Of the 276 patients tested, 93 did not respond to either control antigen, but five of these patients had a positive TST, leaving 88 (32%) anergic. Anergy was related to age, immunosuppressive drug use, and the reagents used, but not to urea reduction ratio. Positive TSTs were found in 17 of 188 of nonanergic patients (9%) (6% of all tested patients). Overall, 48 of 307 patients (16%) had a positive TST or history of TB. TB or a positive TST was associated with liver disease and peptic ulcer disease, but not socioeconomic status. All 17 newly identified TST-positive patients received chest radiographs. No new cases of active TB were found. Only two of 17 of these patients (12%) were started on isoniazid (INH) prophylaxis. We identified high rates of TST positivity and anergy in the hemodialysis patients tested. Hemodialysis patients should receive regular TST screening, and INH prophylaxis needs to be more strongly encouraged. Studies are ongoing to define the rate of TST conversion over time.     

Glutathione peroxidase (GPX) activity in seminal plasma of healthy and infertile males

Human spermatozoa are more dependent on glutathione peroxidase/glutathione reductase (GPX/GR) system, via reduced glutathione (GSH), to inactivate reactive oxygen metabolites (ROMs) such as hydrogen peroxide and organic hydroperoxides. To demonstrate whether there is a substantial difference in GPX activity between normal and pathological seminal plasma, we decided to evaluate the activity of this enzyme in healthy subjects and infertile males with normal hormonal patterns. Our results demonstrate that in healthy subjects the seminal plasma contains a GPX activity that is about 10 times greater than the GPX activity detected in the seminal plasma of infertile males. By using specific antibodies against plasmatic GPX (GPX3), we also demonstrate that enzymatic activity, detected in the seminal plasma of both healthy and infertile males is GPX3. Therefore, the evaluation of GPX activity in human seminal plasma could be a new useful marker of gonadal function in men.