The prevalence of nonalcoholic fatty liver disease in the Americas.

Nonalcoholic fatty liver disease (NAFLD) is an alarming public health problem. The disease is one of the main causes of chronic liver disease worldwide and is directly linked to the increased prevalence of obesity and type 2 diabetes mellitus (T2DM) in the general population. The worldwide prevalence of NAFLD has been estimated at 20-30%, but the prevalence is unknown in the Americas because of a lack of epidemiological studies. However, given the trends in the prevalence of diabetes and obesity, the prevalence of NAFLD and its consequences are expected to increase in the near future. The aim of the present study is to present the current data on the prevalence of NAFLD in the Americas. We performed an electronic search of the main databases from January 2000 to September 2013 and identified 356 reports that were reviewed. We focused on the epidemiology and prevalence of known NAFLD risk factors including obesity, T2DM, and the metabolic syndrome (MS). The prevalence of the MS was highest in the United States, Mexico, Costa Rica, Puerto Rico, Chile, and Venezuela. In addition, Puerto Rico, Guyana, and Mexico have the highest prevalence of T2DM in the Americas, while USA has the most people with T2DM. In conclusion, the prevalence rates of NAFLD and obesity were highest in the United States, Belize, Barbados, and Mexico.

Hepatic manifestations of metabolic syndrome.

The prevalence of metabolic syndrome is growing around the world at an alarming rate. Obesity involves a plethora of molecules that predispose individuals to an inflammatory state and various metabolic complications. Dysregulation of nutrient metabolism is a key step during the progression of chronic liver disease that induces an inflammatory state, cellular damage, and impaired hepatic insulin signaling, which leads to insulin resistance. Insulin resistance arises from multiple defects in the liver, adipose tissues, and muscle signaling, which leads to a failure to suppress hepatic gluconeogenesis and glycogenolysis, thereby enhancing fat accumulation in the hepatocytes via increased lipolysis and increased hepatic synthesis of triglycerides. This metabolic condition also increases the frequency of other comorbidities such as liver and biliary diseases. Nonalcoholic fatty liver disease is the hepatic expression of metabolic syndrome, which comprises a spectrum of clinical and histological events ranging from simple and benign fatty liver to steatohepatitis, which is characterized by the abnormal activation of pathways leading to an aggressive inflammatory condition. This pathological state may progress to more severe damage known as cirrhosis, which endangers the anatomy and function of liver tissue. In addition, a small group of patients with end-stage liver disease may develop hepatocellular carcinoma and finally death. By contrast, cholesterol gallstone disease is a common metabolic disease, and is considered to be the main biliary indicator of metabolic syndrome. This review provides a detailed summary of the hepatic manifestations associated with metabolic syndrome. Copyright © 2013 John Wiley & Sons, Ltd.

Bilirubin alone as a biomarker for short-term mortality in acute-on-chronic liver failure: an important prognostic indicator.

BACKGROUND AND AIMS. Acute-on-chronic liver failure has been recognized as a sudden deterioration of cirrhosis, with a high short-term mortality. Prognostic scores are used to assess liver dysfunction. However, there is not enough information on a score to predict short term mortality in those patients. We aimed to investigate the prognostic value of bilirubin concentration in predicting the 1-week outcome of patients with acute-on-chronic liver failure. MATERIAL AND METHODS. We performed a retrospective analysis with a cohort of 65 patients (33 women/32 men), age average of 64 years, diagnosed with acute-on-chronic liver failure with at least 1 week follow-up. Demographics, clinical and biochemical variables were analyzed. Most patients died (59 %) within 1 week of follow-up. RESULTS. In univariate logistic regression analysis, admission to the intensive care unit, use of vasoactive drugs, need for parenteral nutrition, and levels of conjugated, unconjugated, and total bilirubin at the time of hospital admission were significantly associated with 1-week mortality; in a multivariate logistic regression, conjugated (p = 0.01), unconjugated (p =0.01), and total bilirubin (p = 0.009) were independently associated with 1-week mortality. In ROC curve analysis, conjugated (0.751, p < 0.05) and total bilirubin (0.746, p < 0.05) levels were significantly the best short-term mortality predictors. CONCLUSIONS. High levels of bilirubin are able to predict short-term mortality in these patients. Also, we suggest that bilirubin can be used as a biochemical marker to improve triage of patients with acute-on-chronic liver failure especially with emerging interventions such as extracorporeal liver assist devices and possibly improved early phase pharmacological therapies.

Nuclear receptors in nonalcoholic Fatty liver disease.

Nuclear receptors comprise a superfamily of ligand-activated transcription factors that are involved in important aspects of hepatic physiology and pathophysiology. There are about 48 nuclear receptors in the human. These nuclear receptors are regulators of many hepatic processes including hepatic lipid and glucose metabolism, bile acid homeostasis, drug detoxification, inflammation, regeneration, fibrosis, and tumor formation. Some of these receptors are sensitive to the levels of molecules that control lipid metabolism including fatty acids, oxysterols, and lipophilic molecules. These receptors direct such molecules to the transcriptional networks and may play roles in the pathogenesis and treatment of nonalcoholic fatty liver disease. Understanding the mechanisms underlying the involvement of nuclear receptors in the pathogenesis of nonalcoholic fatty liver disease may offer targets for the development of new treatments for this liver disease.