The 148 Isoleucine to Methionine protein variant (I148M) of patatin-like phospholipase domain-containing 3 (PNPLA3), a protein is expressed in the liver and is involved in lipid metabolism, has recently been identified as a major determinant of liver fat content. Several studies confirmed that the I148M variant predisposes towards the full spectrum of liver damage associated with fatty liver: from simple steatosis to steatohepatitis and progressive fibrosis. Furthermore, the I148M variant represents a major determinant of progression of alcohol related steatohepatitis to cirrhosis, and to influence fibrogenesis and related clinical outcomes in chronic hepatitis C virus hepatitis, and possibly chronic hepatitis B virus hepatitis, hereditary hemochromatosis and primary sclerosing cholangitis. All in all, studies suggest that the I148M polymorphism may represent a general modifier of fibrogenesis in liver diseases. Remarkably, the effect of the I148M variant on fibrosis was independent of that on hepatic steatosis and inflammation, suggesting that it may affect both the quantity and quality of hepatic lipids and the biology of non-parenchymal liver cells besides hepatocytes, directly promoting fibrogenesis. Therefore, PNPLA3 is a key player in liver disease progression. Assessment of the I148M polymorphism will possibly inform clinical practice in the future, whereas the determination of the effect of the 148M variant will reveal mechanisms involved in hepatic fibrogenesis.
Nonalcoholic fatty liver disease (NAFLD), tightly linked to the metabolic syndrome (MS), has emerged as a leading cause of chronic liver disease worldwide. Since it is potentially progressive towards non-alcoholic steatohepatitis (NASH) and hepatic fibrosis, up to cirrhosis and its associated complications, the need for predictive factors of NAFLD and of its advanced forms is mandatory. Despite the current “gold standard” for the assessment of liver damage in NAFLD being liver biopsy, in recent years, several non-invasive tools have been designed as alternatives to histology, of which fibroscan seems the most promising. Among the different serum markers considered, serum uric acid (SUA) and ferritin have emerged as possible predictors of severity of liver damage in NAFLD. In fact, as widely described in this review, they share common pathogenetic pathways and are both associated with hepatic steatosis and MS, thus suggesting a likely synergistic action. Nevertheless, the power of these serum markers seems to be too low if considered alone, suggesting that they should be included in a wider perspective together with other metabolic and biochemical parameters in order to predict liver damage.
Nonalcoholic fatty liver disease (NAFLD) is prevalent in 20–25% of the general population and is associated with metabolic risk factors such as obesity, diabetes mellitus, and dyslipidemia. Histologically, NAFLD ranges from simple steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. As NASH develops in only 10–15% of patients with NAFLD, it is not practical to biopsy all patients who present with NAFLD. Noninvasive fibrosis tests have been extensively developed recently and offer alternatives for staging fibrosis. Despite their increasing use, such tests cannot adequately differentiate simple steatosis from NASH. At present, such tests can be used as first line tests to rule out patients without advanced fibrosis and thus prevent unnecessary secondary care referrals in a significant number of patients. In this review we present the evidence for the use of noninvasive fibrosis tests in patients with NAFLD.
Background & Aims: Non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are closely associated, and liver fibrosis has been related to macrovascular complications. We examined whether liver fibrosis, diagnosed by FibroScan ® , correlates with chronic vascular complications in a cohort of T2DM.
Methods:We recruited 394 outpatients with T2DM attending five Italian diabetes centres who underwent liver ultrasonography (US), FibroScan ® and extensive evaluation of macrovascular and microvascular diabetic complications.Results: Steatosis by US was present in 89%. Almost all patients (96%) were on hypoglycaemic drugs, 58% had at least one chronic vascular complication, 19% a macrovascular complication (prior myocardial infarction and/or ischaemic stroke) and 33% a microvascular one (26% chronic kidney disease [CKD]; 16% retinopathy; 6% neuropathy). In all, 171 (72%) patients had CAP ≥ 248dB/m (ie hepatic steatosis), whereas 83 (21%) patients had LSM ≥ 7.0/6.2 kPa (M/XL probes) (significant liver fibrosis). CAP was not associated with any macro/microvascular complications, whereas LSM ≥ 7.0/6.2 kPa was independently associated with prior cardiovascular disease (adjusted OR 3.3, 95%CI 1.2-8.8; P = .02) and presence of microvascular complications (adjusted OR 4.2, 95%CI 1.5-11.4; P = .005), mainly CKD (adjusted OR 3.6, 95%CI 1.3-10.1; P = .01) and retinopathy (adjusted OR 3.7, CI 95% 1.2-11.9; P = .02). Neither diabetes duration nor haemoglobin A1c differed according to CAP or LSM values.Conclusion: Significant fibrosis, detected by FibroScan ® , is independently associated with increased prevalence of macrovascular and microvascular complications, thus opening a new scenario in the use of this tool for a comprehensive evaluation of hepatic and vascular complications in patients with T2DM.
Due to the very low quality evidence, we are very uncertain about the effectiveness of pharmacological treatments for people with NAFLD including those with steatohepatitis. Further well-designed randomised clinical trials with sufficiently large sample sizes are necessary.
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