Nowadays, obesity is one of the most prevalent human health problems. Research from the last 30 years has clarified the role of the imbalance between energy intake and expenditure, unhealthy lifestyle, and genetic variability in the development of obesity. More recently, the composition and metabolic functions of gut microbiota have been proposed as being able to affect obesity development. Here, we will report the current knowledge on the definition, composition, and functions of intestinal microbiota. We have performed an extensive review of the literature, searching for the following keywords: metabolism, gut microbiota, dysbiosis, obesity. There is evidence for the association between gut bacteria and obesity both in infancy and in adults. There are several genetic, metabolic, and inflammatory pathophysiological mechanisms involved in the interplay between gut microbes and obesity. Microbial changes in the human gut can be considered a factor involved in obesity development in humans. The modulation of the bacterial strains in the digestive tract can help to reshape the metabolic profile in the human obese host as suggested by several data from animal and human studies. Thus, a deep revision of the evidence pertaining to the use probiotics, prebiotics, and antibiotics in obese patients is conceivable

Biochemical response to ursodeoxycholic acid (UDCA) in patients with primary biliary cirrhosis (PBC) is variable. It has been recently proposed that an alkaline phosphatase (ALP) decline of more than 40% in baseline value or a normal level after 1 year of UDCA treatment (Barcelona criteria) could serve as a good marker of long-term prognosis. Our aim was to define the best efficient set of biochemistries able to identify UDCA-treated patients at risk of death or liver transplantation (LT). The efficiency of several combinations of serum bilirubin, ALP, and aspartate aminotransferase (AST) threshold values to predict outcome was assessed after 1 year of treatment in 292 patients with PBC. Patients showing ALP <3 upper limit of normal (ULN), AST <2 ULN, and bilirubin ≤1 mg/dL after 1 year of UDCA had a 10-year transplant-free survival rate of 90% (95% confidence interval, 81%–95%), compared to 51% (95% confidence interval, 38%–64%) for those who did not ( P < 0.001). Patients were less well discriminated by the Barcelona criteria (79% versus 63%). Independent predictive factors of death or LT were baseline serum bilirubin level >1 mg/dL (relative risk [RR], 1.7), histologic stage ≥3 (RR, 1.5), interface hepatitis (RR, 1.9), and the absence of biochemical response (ALP >3 ULN or AST >2 ULN, or bilirubin >1 mg/dL) (RR, 2.3). Antinuclear antibodies against gp210 or Sp100 proteins were associated with death or LT in univariate but not in multivariate analysis. Conclusion: This study defines the best efficient biochemical response to UDCA, which, independent of baseline predictive factors, identifies patients with PBC with a good long-term prognosis. Patients who fail to achieve this response and those with interface hepatitis or advanced histological stage should be targeted for further therapeutic research. (Hepatology 2008.)

Non Alcoholic Fatty Liver Disease (NAFLD), defined as the presence of a significant amount of lipid accumulation in the liver (at least in 5% of hepatocytes), represents a challenging issue for the Hepatologists. NAFLD is not represented by a single entity, but rather by two different entities that have different natural history and evolution that range from simple fat accumulation in the liver (without any consequence), to necroinflammation, fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The reason of these differences has to be found in the host characteristics and associated risk factors. Globally, its prevalence among liver diseases, and in the general population, is rising in the recent years along with its associated conditions: obesity, insulin resistance, metabolic syndrome and diabetes. This increment, together with the reported clinical conditions, may be accounted for changes in dietary habits and the increase of sedentary lifestyle. Its diffusion seems to be pandemic, given that it is beginning to affect the populations in the developing world due to the spread of Western lifestyle. This is particularly worrying in young adults and children in what seems to have become the main cause of liver disease. Even if the real rate of global incidence of NAFLD are not known, its worldwide prevalence in general population is estimated to be 20-30% in Western Countries and 5-18% in Asia and it is increasing over time. In this review we will report on the global and regional prevalence of NAFLD, the principal risk factors and the natural history of its different presentations.