Background and AimsNonalcoholic fatty liver disease is epidemiologically associated with hepatic and metabolic disorders. The aim of this study was to examine whether hepatic fat accumulation has a causal role in determining liver damage and insulin resistance.MethodsWe performed a Mendelian randomization analysis using risk alleles in PNPLA3, TM6SF2, GCKR and MBOAT7, and a polygenic risk score for hepatic fat, as instruments. We evaluated complementary cohorts of at‐risk individuals and individuals from the general population: 1515 from the liver biopsy cohort (LBC), 3329 from the Swedish Obese Subjects Study (SOS) and 4570 from the population‐based Dallas Heart Study (DHS).ResultsHepatic fat was epidemiologically associated with liver damage, insulin resistance, dyslipidemia and hypertension. The impact of genetic variants on liver damage was proportional to their effect on hepatic fat accumulation. Genetically determined hepatic fat was associated with aminotransferases, and with inflammation, ballooning and fibrosis in the LBC. Furthermore, in the LBC, the causal association between hepatic fat and fibrosis was independent of disease activity, suggesting that a causal effect of long‐term liver fat accumulation on liver disease is independent of inflammation. Genetically determined hepatic steatosis was associated with insulin resistance in the LBC and SOS. However, this association was dependent on liver damage severity. Genetically determined hepatic steatosis was associated with liver fibrosis/cirrhosis and with a small increase in risk of type 2 diabetes in publicly available databases.ConclusionThese data suggest that long‐term hepatic fat accumulation plays a causal role in the development of chronic liver disease.

BACKGROUND & AIMS: In patients with nonalcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH) is a risk factor for the development of fibrosis. However, fibrosis has been observed in livers of patients without NASH. We aimed to estimate the prevalence of fibrosis in patients without NASH and risk factors for fibrosis. METHODS: We analyzed data from 1738 subjects (44.9% with severe obesity) in a cross-sectional liver biopsy cohort enrolled at referral centers in Italy and Finland. Biopsy specimens were analyzed histologically by a blinded pathologist at each center, and a diagnosis of NASH was made based on steatosis (‡5% of hepatocytes), hepatocellular ballooning, and lobular inflammation. We also collected data on demographic features, metabolic comorbidities, and genetic factors, and performed logistic regression analyses. Findings were validated using data from 118 consecutive patients with NAFLD who underwent sequential liver biopsies at tertiary referral centers in Italy. RESULTS: In the cross-sectional cohort, 132 of 389 patients (33.9%) with significant fibrosis had no NASH and 39 patients (10.0%) had no inflammation. The dissociation between NASH and fibrosis was significantly greater in patients with severe obesity (P < .005). Steatosis, ballooning, and lobular inflammation each were associated independently with significant fibrosis (P < .001); age, adiposity, fasting hyperglycemia, and the PNPLA3 I148M variant also were associated with fibrosis. In patients without, but not in those with NASH, significant fibrosis was associated with steatosis grade and the PNPLA3 I148M variant. In patients without NASH, age, fasting hyperglycemia, ballooning, and inflammation were associated with fibrosis. In the validation cohort, 16 of 47 patients (34.0%) with clinically significant fibrosis did not have NASH at baseline. In patients with fibrosis without baseline NASH, worsening of fibrosis (based on later biopsies) was associated with fasting hyperglycemia and more severe steatosis (P [ .016).

Dyslipidemia and altered iron metabolism are typical features of nonalcoholic fatty liver disease (NAFLD). Proprotein convertase subtilisin/kexin type 7 (PCSK7) gene variation has been associated with circulating lipids and liver damage during iron overload. The aim of this study was to examine the impact of the PCSK7 rs236918 variant on NAFLD-related traits in 1,801 individuals from the Liver Biopsy Cohort (LBC), 500,000 from the UK Biobank Cohort (UKBBC), and 4,580 from the Dallas Heart Study (DHS). The minor PCSK7 rs236918 C allele was associated with higher triglycerides, aminotransferases, and hepatic inflammation in the LBC (P < 0.05) and with hypercholesterolemia and liver disease in the UKBBC. In the DHS, PCSK7 missense variants were associated with circulating lipids. PCSK7 was expressed in hepatocytes and its hepatic expression correlated with that of lipogenic genes (P < 0.05). The rs236918 C allele was associated with upregulation of a new “intra-PCSK7” long noncoding RNA predicted to interact with the protein, higher hepatic and circulating PCSK7 protein (P < 0.01), which correlated with triglycerides (P = 0.04). In HepG2 cells, PCSK7 deletion reduced lipogenesis, fat accumulation, inflammation, transforming growth factor β pathway activation, and fibrogenesis. In conclusion, PCSK7 gene variation is associated with dyslipidemia and more severe liver disease in high risk individuals, likely by modulating PCSK7 expression/activity.

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This narrative review will discuss the current evidence supporting the possible application of precision or personalized medicine to the management of nonalcoholic or “metabolic” fatty liver disease (NAFLD), based on recent progress in the understanding of the genetics and epigenetics of the disease. The prevalence of NAFLD, which can progress to cirrhosis and hepatocellular carcinoma, is constantly increasing worldwide. Accurate noninvasive predictors of liver disease progression, as well as of cardiovascular complications of NAFLD, are urgently needed. Evidence is now reporting that the genetic and epigenetic factors involved in NAFLD development can be used to develop risk scores for liver-related complications, which may show the possibility to implement programs for targeted screening and surveillance of complications. Moreover, genetic and epigenetic factors identifying specific sub-phenotypes of NAFLD can predict the individual response to pharmacological therapies. Finally, we describe opportunities for gene-targeted therapeutic approaches in NAFLD, where the genetic variants represent therapeutic targets for precision therapy approaches.

Sarcopenia is defined as a loss of muscle strength, mass and function and it is a predictor of mortality. Sarcopenia is not only a geriatric disease, but it is related to several chronic conditions, including liver diseases in both its early and advanced stages. Despite the increasing number of studies exploring the role of sarcopenia in the early stages of chronic liver disease (CLD), its prevalence and the relationship between these two clinical entities are still controversial. Myosteatosis is characterized by fat accumulation in the muscles and it is related to advanced liver disease, although its role in the early stages is still under researched. Therefore, in this narrative review, we firstly aimed to evaluate the prevalence and the pathogenetic mechanisms underlying sarcopenia and myosteatosis in the early stage of CLD across different aetiologies (mainly non-alcoholic fatty liver disease, alcohol-related liver disease and viral hepatitis). Secondly, due to the increasing prevalence of sarcopenia worldwide, we aimed to revise the current and the future therapeutic approaches for the management of sarcopenia in CLD.

Currently, chronic obstructive pulmonary disease (COPD) represents the fourth cause of death worldwide with significant economic burden. Comorbidities increase in number and severity with age and are identified as important determinants that influence the prognosis. In this observational study, we retrospectively analyzed data collected from the RePoSI register. We aimed to investigate comorbidities and outcomes in a cohort of hospitalized elderly patients with the clinical diagnosis of COPD. Socio-demographic, clinical characteristics and laboratory findings were considered. The association between variables and in-hospital, 3-month and 1-year follow-up were analyzed. Among 4696 in-patients, 932 (19.8%) had a diagnosis of COPD. Patients with COPD had more hospitalization, a significant overt cognitive impairment, a clinically significant disability and more depression in comparison with non-COPD subjects. COPD patients took more drugs, both at admission, in-hospital stay, discharge and 3-month and 1-year follow-up. 14 comorbidities were more frequent in COPD patients. Cerebrovascular disease was an independent predictor of in-hospital mortality. At 3-month follow-up, male sex and hepatic cirrhosis were independently associated with mortality. ICS-LABA therapy was predictor of mortality at in-hospital, 3-month and 1-year follow-up. This analysis showed the severity of impact of COPD and its comorbidities in the real life of internal medicine and geriatric wards.