Statins and HCV: a complex issue.
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Biomedical subjects
Publications and source records attributed to Nicola Carulli.
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AIM: To evaluate carotid intima-media thickening (IMT) and plaques, gallstone disease (GD) and fatty liver (FL) as a function of age. METHODS: In 449 subjects, FL and carotid disease were assessed ultrasonographically. In a subgroup of 65/449 patients with non-alcoholic fatty liver disease (NAFLD), carotid disease, GD and associated factors were determined. RESULTS: FL of unspecified etiology was more common in younger and GD in older individuals. FL subjects had an increased prevalence of IMT and a decreased prevalence of plaques and manifested carotid disease earlier. Plaques were more common in subjects with GD. Age was an independent predictor of carotid disease outcome and FL was a protective factor for plaques. In NAFLD, there was an inverse correlation between body weight and age and the latter independently predicted carotid findings. CONCLUSION: Cardiovascular risk in patients with FL and NAFLD needs to be assessed as a function of age and body weight.
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BACKGROUND: Epidemiological and clinical studies suggest the possibility that estrogens might have a cytoprotective effect on the liver. The aim of the present study was to test the hypothesis that 17beta-estradiol (E2) prevents hepatocellular damage induced by deoxycholic acid (DCA), a hydrophobic bile acid. METHODS: HepG2 cells were exposed for 24 h to DCA (350 micromol/L). Cell viability, aspartate aminotransferase and lactate dehydrogenase activity and apoptosis were measured as indices of cell toxicity. The effect of DCA was compared to that observed using either a hydrophilic bile acid, ursodeoxycholic acid (UDCA; 100 micromol/L), or E2 at different concentrations (1 nmol/L, 10 nmol/L, 50 nmol/L and 50 micromol/L) or mixtures of E2/DCA or UDCA/DCA. The same experiments were performed using WRL-68 cells that, at variance with HepG2, express a higher level of nuclear estrogen receptor. RESULTS: High concentrations of E2 and UDCA prevented DCA-induced decrease in cell viability, increase in enzyme activity and apoptosis evaluated both by 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) and TdT-mediated dUTP nick-end labeling (TUNEL) assays. In addition, DCA-related apoptosis, assessed by caspase activity, was also prevented by E2 (P < 0.01) in physiological (1-10 nmol/L) doses. The cytoprotective effects of E2 and UDCA was also observed in the WRL-68 cell line. CONCLUSIONS: 17Beta-Estradiol prevents DCA-induced cell damage in HepG2 and WRL-68 cell lines to an extent comparable to UDCA. The hypothesis that the protective effect of E2 may be mediated by a mechanism that is nuclear estrogen receptor independent, deserves further verification.
AIM: To evaluate the influence of familiality on the prevalence of gallstone disease (GD) in Italy. METHODS: Families of 79 subjects with gallstones (cases) and of 79 subjects without gallstones (controls) were investigated for the presence of gallstones by ultrasonography. Index cases and index controls were matched for age, sex, and operative unit. Sixty-three and sixty-two husbands and wives of index cases and index controls, respectively, were also studied. RESULTS: Overall, the prevalence of GD was significantly higher (c2=14.52, P<0.001) in the 202 first-degree relatives of subjects with gallstones than that in the 201 first-degree relatives of subjects without gallstones (28.6% vs 12.4%, relative risk (RR) 1.80, 95% confidence interval (CI) 1.29-2.63). In particular, prevalence of GD was significantly higher in mothers, fathers, and sisters of index cases than that in the respective family members of index controls. The highest RR was observed in mothers (RR=2.35, 95%CI 1.38-4.3). Prevalence of GD was not obviously different in brothers and also in husbands and wives of index cases and index controls. Family members of index cases did not differ from family members of control cases with respect to the most important risk factors for gallstones (age, diabetes, BMI, and number of pregnancies) with an exception of a higher prevalence of diabetes in fathers of index controls than in fathers of index cases. CONCLUSION: This study confirms that familiality plays a very important role in the pathogenesis of gallstones.
BACKGROUND/AIMS: To ascertain whether the etiology of hepatic steatosis modulates insulin resistance (IR) and to determine the predictors of IR. METHODS: We studied IR through HOMA IR in 146 subjects, 99 of whom had ultrasonographic and/or histologic steatosis. Twenty-two had familial heterozygous hypobetalipoproteinemia (FHBL), 48 had non-alcoholic fatty liver disease (NAFLD), 34 HCV infection (17 with HCV1b, 17 with HCV3a) and 42 were healthy controls without steatosis. RESULTS: Steatosis was present in 77.3% of FHBL and, by enrolment criteria, in all NAFLD and HCV cases. Overall HOMA-IR correlated with BMI and GGT (P<0.01). FHBL and healthy groups had similar HOMA-IR and GGT values, whereas higher levels were observed in HCV and NAFLD. HCV3a and FHBL patients were hypolipidemic. HOMA-IR was similar in FHBL patients and controls and lower than in HCV and NAFLD. FHBL patients had a high extent of steatosis, similar to that observed in HCV3a, but lower grading and staging than NAFLD and HCV. At multivariate analysis, steatosis and GGT predicted HOMA-IR. CONCLUSIONS: Data suggest that not all hepatic fat associates with IR. FHBL patients, for some aspects, resemble HCV3a infection, possibly suggesting a shared steatogenic mechanism. Among steatotic patients serum GGT levels is the independent predictor of IR.
BACKGROUND: Insulin resistance is a risk factors for non-alcoholic fatty liver disease (NAFLD) and for gallstone disease (GD). Aims of the present study were to assess the prevalence of and factors associated with GD in unselected patients with NAFLD. METHODS: A total of 161 consecutive patients with NAFLD diagnosed through compatible ultrasonography in the absence of known etiologies of liver disease (in all patients) and/or confirmed histologically (in 61 patients), was studied. Gallstone disease was diagnosed through ultrasound scanning or on the basis of previous cholecystectomy. Anthropometric and biochemical variables and concurrent diseases were compared in 32 NAFLD-GD patients and in 129 NAFLD patients without GD (controls) according to gender. RESULTS: The overall prevalence of GD was 19.88%, higher in female patients (P < 0.05), who were older (P < 001). The overall percentage of GD increased with age (P < 0.05). The GD patients had higher uric acid (men), total cholesterol and apolipoprotein B (apo-B) serum concentrations (women; P < 0.05); women also had a higher prevalence of hypertriglyceridemia (P < 0.05). The age-corrected odds ratio of having GD by tertiles increased significantly with increasing uric acid (men) and with increasing total cholesterol, triglycerides and apo-B (women). At univariate continuous analysis GD was associated with insulin 120 min and uric acid in male patients; and with body mass index, insulin 120 min, apo-B, total cholesterol and triglycerides in female patients. On multivariate analysis it was found that among these factors only uric acid in men and apo-B in women were independently associated with GD in NAFLD. CONCLUSIONS: The prevalence of GD in NAFLD is more elevated than reported in the general population. The factors independently associated with GD in NAFLD are different from those reported in the general population and vary according to the gender.
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BACKGROUND: None of the synonyms of nonalcoholic fatty liver disease (NAFLD) include clinical correlates nor do they mention insulin resistance, a recognized determinant of the etiopathogenesis and natural history of NAFLD. METHOD: The literature concerning the pathogenesis and definition of NAFLD is reviewed. RESULTS: The reasons why NAFLD should be renamed are: (a) clinically meaningful hepatic steatosis could be present at less than 5% triglyceride hepatic content; (b) steatosis is usually no longer observed in the most advanced forms of NAFLD ('cryptogenic cirrhosis'); (c) the concurrence of metabolic derangements could be more important than alcohol in the pathogenesis of alcoholic liver disease; (d) a concurrent metabolic etiology might worsen the course of chronic HCV and autoimmune hepatitis; (e) in NAFLD the liver is a target organ of the metabolic syndrome, a systemic subclinical inflammatory state. CONCLUSION: The introduction of a positive criterion also mentioned in its definition would benefit the diagnosis of NAFLD and of steatohepatitis observed in the setting of other liver diseases, help to estimate the risk of its progression and aid the treatment of metabolic (fatty) liver disorders. There is a compelling need for an experts' agreement on a new definition of insulin resistance/metabolic-related liver disease.
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Nonalcoholic fatty liver disease (NAFLD) and hepatitis C virus (HCV)-related liver disease are common in the general population, but their concurrence is 2- to 3-fold higher than would be expected by chance alone. In patients with chronic HCV infection, steatosis is attributable to a variable combination of the mechanisms considered to play a role in the pathogenesis of NAFLD--insulin resistance in the obese and in the lean subject--along with a direct effect of HCV on hepatic lipid metabolism that leads to triglyceride accumulation through inhibition of export proteins that are required for very low density lipoprotein (VLDL) assembly and secretion. Accumulating evidence suggests that steatosis contributes to the progression of fibrosis in HCV-related disease in a pattern similar to that observed in NAFLD. Potential mechanisms of this effect include the increased sensitivity of steatotic livers to oxidative stress and cytokine-mediated injury. Steatosis-related hepatic insulin resistance may also play a role through the profibrogenic effects of the compensatory hyperinsulinemia and provides a potential explanation for the association between HCV and type 2 diabetes mellitus. Indeed, an appreciation of the importance of fat in HCV has recently led to trials of adjuvant therapy for HCV directed at steatosis-associated disease mechanisms, with encouraging results reported for various modalities, including weight loss and antioxidants. Future therapy should be aimed at exploiting the interactions of HCV with host insulin and lipid metabolism, particularly in nonresponders to standard antiviral schedules.
Eighty-four consecutive subjects with nonalcoholic fatty liver disease (NAFLD) were tested for non-organ-specific autoantibodies (NOSA) by indirect immunoflorescence. Indices of insulin resistance and biochemical and anthropometric parameters were assessed. The overall prevalence of anti-nuclear-antibodies (ANA), smooth muscle antibodies (SMA) and anti-mitochondrial-antibodies (AMA) was 35.7% (30/84), 18 subjects (21.4%) being positive for ANA, 4 (4.7%) for SMA, 6 for ANA and SMA, and 2 for AMA. NOSA-positive subjects were older (P < 0.01) and mostly females (63.3%). No significant difference was found in the age-corrected parameters studied, except for copper and ceruloplasmin, which was more elevated in NOSA-positive patients. The subset of high titer (>1:100) ANA-positive patients had significantly (P < 0.05) greater insulin resistance than ANA-negative patients. In contrast, SMA-positive patients had higher gammaglobulin and significantly lower insulin resistance as compared to high-titer ANA-positive patients. In 3 NOSA-positive but not in NOSA-negative patients, liver biopsy disclosed features of overlapping NASH with autoimmune hepatitis, partially responding to diet combined with steroid treatment. In conclusion, NOSA positivity in NAFLD is more prevalent than in the general population. High-titre ANA but not SMA positivity is associated with insulin resistance.
The effects of newly synthesized cholesterol availability on bile acid synthesis are largely unknown, particularly in humans. The present study was aimed to study the changes induced on bile acid synthesis by simvastatin, a competitive inhibitor of hydroxymethyl glutaryl-CoA (HMG-CoA) reductase, the rate-limiting enzyme of cholesterol synthesis, during pharmacologic interruption of the enterohepatic circulation. Six patients with primary hypercholesterolemia were studied in basal conditions, after treatment with the bile acid binding resin cholestyramine alone (8-16 g/d for 6-8 weeks) and subsequently in combination with simvastatin (40 mg/d for 6-8 weeks). Cholesterol 7alpha-hydroxylation rate, a measure of total bile acid synthesis, was assayed in vivo by tritium release analysis. Serum lathosterol levels were assayed by gas chromatography-mass spectrometry as a measure of cholesterol synthesis. Serum total and low-density lipoprotein-cholesterol were reduced significantly after cholestyramine (by 26% and 30%, respectively) and during combined treatment (by 47% and 55%). 7alpha-hydroxylation rates increased nearly 4-fold with cholestyramine alone; addition of simvastatin induced a significant decrease of hydroxylation rates (cholestyramine alone, 1,591 +/- 183 mg/d; plus simvastatin, 1,098 +/- 232 mg/d; mean +/- SEM; P <.05). Hydroxylation rates significantly correlated with serum lathosterol/cholesterol ratio (r = 0.79, P <.05). In conclusion, in conditions of chronic stimulation bile acid synthesis may be affected by changes in newly synthesized cholesterol availability. The finding might relate to the degree of substrate saturation of microsomal cholesterol 7alpha-hydroxylase; alternatively, newly synthesized cholesterol might induce a stimulatory effect on cholesterol 7alpha-hydroxylase transcription.
This study was performed to compare the effects of two hydrophilic bile acids, taurohyodeoxycholic acid (THDCA) and tauroursodeoxycholic acid (TUDCA), on HepG2 cells. Cytotoxicity was evaluated at different times of exposure by incubating cells with increasing concentrations (50-800 micromol/l) of either bile acid, while their cytoprotective effect was tested in comparison with deoxycholic acid (DCA) (350 micromol/l and 750 micromol/l)-induced cytotoxicity. Culture media, harvested at the end of each incubation period, were analyzed to evaluate aspartate transaminase (AST), alanine transaminase and gamma-glutamyltranspeptidase release. In addition, the hemolytic effect of THDCA and TUDCA on human red blood cells was also determined. At 24 h of incubation neither THDCA nor TUDCA was cytotoxic at concentrations up to 200 and 400 micromol/l. At 800 micromol/l both THDCA and TUDCA induced a slight increase in AST release. At this concentration and with time of exposure prolonged up to 72 h, THDCA and TUDCA induced a progressive increase of AST release significantly (P<0.05) higher than that of controls being AST values for THDCA (2.97+/-0.88 time control value (tcv) at 48 h and 4.50+/-1.13 tcv at 72 h) significantly greater than those of TUDCA (1.50+/-0.20 tcv at 48 h and 1.80+/-0.43 tcv at 72 h) (P<0.01). In cytoprotection experiments, the addition of 50 micromol/l THDCA decreased only slightly (-5%) AST release induced by 350 micromol/l DCA, while the addition of 50 micromol/l TUDCA was significantly effective (-23%; P<0.05). Higher doses of THDCA or TUDCA did not reduce toxicity induced by 350 micromol/l DCA, but were much less toxic than an equimolar dose of DCA alone. At the concentration used in this experimental model neither THDCA nor TUDCA was hemolytic; however at a very high concentration (6 mmol/l) both bile acids induced 5-8% hemolysis. We conclude that bile acid molecules with a similar degree of hydrophilicity may show different cytotoxic and cytoprotective properties.
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