Paola Loria

Differential effect of oleic and palmitic acid on lipid accumulation and apoptosis in cultured hepatocytes

Background and Aim:  Studies have shown monounsaturated oleic acid to be less toxic than palmitic acid and to prevent/attenuate palmitic acid hepatocites toxicity in steatosis models in vitro. However, to what degree these effects are mediated by steatosis extent is unknown.

Practice guidelines for the diagnosis and management of nonalcoholic fatty liver disease. A decalogue from the Italian Association for the Study of the Liver (AISF) Expert Committee.

We report the evidence-based Italian Association for the Study of Liver guidelines for the appropriate diagnosis and management of patients with nonalcoholic fatty liver disease in clinical practice and its related research agenda. The prevalence of nonalcoholic fatty liver disease varies according to age, gender and ethnicity. In the general population, the prevalence of nonalcoholic fatty liver disease is about 25% and the incidence is of two new cases/100 people/year. 2-3% of individuals in the general population will suffer from nonalcoholic steatohepatitis. Uncomplicated steatosis will usually follow a benign course. Individuals with nonalcoholic steatohepatitis, however, have a reduced life expectancy, mainly owing to vascular diseases and liver-related causes. Moreover, steatosis has deleterious effects on the natural history of HCV infection. Nonalcoholic fatty liver disease is usually diagnosed in asymptomatic patients prompted by the occasional discovery of increased liver enzymes and/or of ultrasonographic steatosis. Medical history, complete physical examination, etiologic screening of liver injury, liver biochemistry tests, serum lipids and insulin sensitivity tests should be performed in every patient. Occult alcohol abuse should be ruled out. Ultrasonography is the first-line imaging technique. Liver biopsy, the gold standard in diagnosis and prognosis of nonalcoholic fatty liver disease, is an invasive procedure and its results will not influence treatment in most cases but will provide prognostic information. Assessment of fibrosis by composite scores, specific laboratory parameters and transient elastography might reduce the number of nonalcoholic fatty liver disease patients requiring liver biopsy. Dieting and physical training reinforced by behavioural therapy are associated with improved nonalcoholic fatty liver disease. Diabetes and the metabolic syndrome should be ruled out at timed intervals in nonalcoholic fatty liver disease. Nonalcoholic steatohepatitis patients should undergo periodic evaluation of cardiovascular risk and of advancement of their liver disease; those with nonalcoholic steatohepatitis-cirrhosis should be evaluated for early diagnosis of hepatocellular carcinoma.

From NAFLD in clinical practice to answers from guidelines

This review of the literature consists of three sections. First, papers concerning non-alcoholic fatty liver disease (NAFLD) awareness among the general population, general practitioners, and liver and non-liver specialists were retrieved and analyzed to highlight the perception of disease, verify knowledge of current recommendations, and identify the main difficulties experienced in clinical practice. Next, position papers and clinical practice guidelines issued by International and National Hepatological Scientific Societies were identified and critically assessed in order to pinpoint the areas of convergence/difference. Finally, practical suggestions on NAFLD diagnosis and management in daily practice are provided and the open questions highlighted.

Nonalcoholic Fatty Liver Disease in HIV-Infected Patients Referred to a Metabolic Clinic: Prevalence, Characteristics, and Predictors

BACKGROUND The prevalence and predictors of nonalcoholic fatty liver disease (NAFLD) in human immunodeficiency virus (HIV)-infected highly active antiretroviral therapy-experienced patients and the association of NAFLD with risk of cardiovascular disease and subclinical atherosclerosis are unknown. METHODS We performed a cross-sectional observational study. NAFLD was defined by liver-spleen attenuation values of <1.1 on computed tomography in persons who had neither evidence of chronic viral hepatitis nor a significant history of alcohol consumption. RESULTS We enrolled 225 patients; 163 (72.4%) were men. Mean (+/-SD) HIV infection duration was 145 +/- 60 months, and mean (+/-SD) body mass index (calculated as weight in kilograms divided by the square of height in meters) was 23.75 +/- 3.59. NAFLD was diagnosed in 83 patients (36.9% of the total cohort). The following variables were significantly associated with NAFLD in univariate analyses: sex, waist circumference, body mass index, cumulative exposure to nucleoside reverse-transcriptase inhibitors, visceral adipose tissue, homeostasis model assessment of insulin resistance index, serum alanine and aspartate aminotransferase levels, and ratios of total serum cholesterol to high-density lipoprotein cholesterol. Coronary artery calcium scores and a diagnosis of diabetes were not associated with NAFLD. In multivariable logistic regression analyses, factors associated (P<0.001) with NAFLD were higher serum alanine to aspartate ratio (odds ratio, 4.59; 95% confidence interval, 2.09-10.08), male sex (odds ratio, 2.49; 95% confidence interval, 1.07-5.81), greater waist circumference (odds ratio, 1.07; 95% confidence interval, 1.03-1.11), and longer nucleoside reverse-transcriptase inhibitor exposure (odds ratio, 1.12 per year of exposure; 95% confidence interval, 1.03-1.22). CONCLUSIONS NAFLD is common among HIV-infected persons who have the traditional risk factors for NAFLD (elevations in serum alanine level, male sex, and increased waist circumference) apparent. Exposure to nucleoside reverse-transcriptase inhibitors was an independent risk factor for NAFLD, with an 11% increase in the odds ratio for each year of use.

Non-organ-specific autoantibodies in nonalcoholic fatty liver disease: prevalence and correlates.

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.

Cholesterol absorption during bile acid feeding: Effect of ursodeoxycholic acid (UDCA) administration

Abstract We studied the effect of ursodeoxycholic acid (UDCA) administration (15 mg/kg/day) on cholesterol absorption in 11 volunteers. Cholesterol absorption was estimated by feeding a standard dose of cholesterol, dissolved in butter, containing 5 μCi of [ 14 C]cholesterol and 10 μCi of [ 3 H]sitosterol (as a nonabsorbable marker). Feces were then collected for 5–6 days. Cholesterol absorption with β-sitosterol, corrected for losses not due to absorption, was estimated from the recovered radioactivity. After 20 days of treatment with UDCA, the study was repeated with each patient acting as his own control. Cholesterol saturation of bile and biliary bile acid composition were also studied before and after treatment. UDCA was virtually undetectable in bile before treatment, but became the most abundant bile acid (42.0 ± 17.2% of the total) after treatment. Although the molar percentage of cholesterol in bile fell in each patient after treatment, bile saturation critically depended on the criteria adopted to calculate the saturation index. Mean cholesterol absorption was 36.7 ± 9.3% of the administered dose in basal conditions and fell to 17.5 ± 11.3% (48% decrement) after treatment (P

Risk of cardiovascular, cardiac and arrhythmic complications in patients with non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) has emerged as a public health problem of epidemic proportions worldwide. Accumulating clinical and epidemiological evidence indicates that NAFLD is not only associated with liver-related morbidity and mortality but also with an increased risk of coronary heart disease (CHD), abnormalities of cardiac function and structure (e.g., left ventricular dysfunction and hypertrophy, and heart failure), valvular heart disease (e.g., aortic valve sclerosis) and arrhythmias (e.g., atrial fibrillation). Experimental evidence suggests that NAFLD itself, especially in its more severe forms, exacerbates systemic/hepatic insulin resistance, causes atherogenic dyslipidemia, and releases a variety of pro-inflammatory, pro-coagulant and pro-fibrogenic mediators that may play important roles in the pathophysiology of cardiac and arrhythmic complications. Collectively, these findings suggest that patients with NAFLD may benefit from more intensive surveillance and early treatment interventions to decrease the risk for CHD and other cardiac/arrhythmic complications. The purpose of this clinical review is to summarize the rapidly expanding body of evidence that supports a strong association between NAFLD and cardiovascular, cardiac and arrhythmic complications, to briefly examine the putative biological mechanisms underlying this association, and to discuss some of the current treatment options that may influence both NAFLD and its related cardiac and arrhythmic complications.

Chronic HCV infection is a risk of atherosclerosis. Role of HCV and HCV-related steatosis

OBJECTIVES HCV and NAFLD are associated with atherosclerosis in general population. The prevalence of atherosclerosis in chronic hepatitis C (CHC) patients is unknown. We hypothesized that HCV per se and HCV-related steatosis could favour atherosclerosis. Thus, in CHC patients we assessed: (a) the prevalence of atherosclerosis; (b) the role of HCV, cardio-metabolic risk factors and hepatic histology. METHODS Overall, 803 subjects were enrolled: (A) 326 patients with liver biopsy-proven treatment naive CHC (175 with and 151 without steatosis); (B) 477 age and gender matched controls, including 292 healthy subjects without steatosis (B1) and 185 with NAFLD (B2). Carotid atherosclerosis (CA), assessed by high-resolution B-mode ultrasonography, was categorized as either intima-media thickness (IMT: >1mm) or plaques (≥ 1.5mm). RESULTS CHC patients had a higher prevalence of CA than controls (53.7% vs 34.3%; p<0.0001). Younger CHC (<50 years) had a higher prevalence of CA than controls (34.0% vs 16.0%; p<0.04). CHC patients without steatosis had a higher prevalence of CA than B1 controls (26.0% vs 14.8%; p<0.02). CHC with steatosis had a higher prevalence of CA than NAFLD patients (77.7% vs 57.8%, p<0.0001). Viral load was associated with serum CRP and fibrinogen levels; steatosis with metabolic syndrome, HOMA-IR, hyperhomocysteinemia and liver fibrosis. Viral load and steatosis were independently associated with CA. Diabetes and metabolic syndrome were associated with plaques. CONCLUSION HCV infection is a risk factor for earlier and facilitated occurrence of CA via viral load and steatosis which modulate atherogenic factors such as inflammation and dysmetabolic milieu.

Effects of acute changes of bile acid pool composition on biliary lipid secretion.

To elucidate the mechanism responsible for the bile acid-induced changes of biliary lipid secretion, we evaluated bile flow and biliary output of bile acids, cholesterol, phospholipids, and alkaline phosphatase activity in seven cholecystectomized subjects with a balloon occludable T-tube during two experimental periods: (a) depletion of the endogenous bile acid pool and (b) replacement of the pool by means of duodenal infusion with individual bile acids, such as deoxycholic (DCA), chenodeoxycholic (CDCA), cholic (CA), and ursodeoxycholic (UDCA) acids. Bile flow, cholesterol, and phospholipid output were linearly related to bile acid secretion in all experimental periods. During the replacement periods, the amount of cholesterol and phospholipids coupled to bile acids was significantly different (at 1% level at least) for each individual bile acid secreted; it was the highest during DCA secretion (slope value: 0.209 for cholesterol and 0.434 for phospholipids) followed, in the order, by CDCA (0.078 and 1.794), CA (0.044 and 0.127), and UDCA (0.030 and 0.122). The phospholipid to cholesterol ratio was higher during secretion of CA and UDCA as compared with DCA and CDCA. The secretion of CA seemed to stimulate a greater bile flow than the other bile acids did. The infusion of all bile acids, except UDCA, induced an increase of biliary alkaline phosphatase activity as compared with the values of the depletion period. The mean highest increase (13-fold the pretreatment value) was observed during DCA secretion followed by CDCA (fivefold) and CA (1.5-fold). These results would suggest that the physical chemical properties, namely the lipid-solubilizing capacity, of bile acids could directly contribute to the regulation of biliary lipid secretion. The observed changes in biliary alkaline phosphatase activity lend support to the view that bile acid-induced lipid secretion may be, at least in part, contributed by membrane solubilization.

Liver and diabetes. A vicious circle

The complex and bi‐directional relationship linking the liver and diabetes has recently gained intense new interest. This critical review of the published work aims to highlight the most recent basic and clinical data underlying the development of type 2 diabetes, in those with non‐alcoholic fatty liver disease. Moreover, the potentially detrimental effects of type 2 diabetes in liver injury are also discussed in each of the two sections of the present paper. Fatty liver and diabetes share insulin resistance as their chief pathogenic determinant. The roles of the hypothalamus, the intestinal microbiome, white adipose tissue and inflammation are discussed in detail. Molecular insights into hepatocyte insulin resistance as the initiator of systemic insulin resistance are also presented with full coverage of the danger of fatty acids. Lipotoxicity, apoptosis, lipoautophagy, endoplasmic reticular stress response and recent developments in genetics are discussed. Closing the circle, special emphasis is given to biochemical pathways and clinical evidence supporting the role of type 2 diabetes as a risk factor for the development of progressive liver disease, including non‐alcoholic steatohepatitis, cirrhosis and primary liver cancer. In conclusion, data support non‐alcoholic fatty liver disease as a risk factor for the development of type 2 diabetes which is, in turn, a major contributor to progressive liver disease. This pathway leading from fatty liver to type 2 diabetes and back from the latter to the progressive liver disease is a vicious circle.