Hepatic-specific Pgc-1α ablation drives fibrosis in a MASH model.

BACKGROUND & AIMS: Metabolic dysfunction-associated steatohepatitis (MASH) is a growing cause of chronic liver disease, characterized by fat accumulation, inflammation and fibrosis, which development depends on mitochondrial dysfunction and oxidative stress. Highly expressed in the liver during fasting, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) regulates mitochondrial and oxidative metabolism. Given the relevant role of mitochondrial function in MASH, we investigated the relationship between PGC-1α and steatohepatitis. METHODS: We measured the hepatic expression of Pgc-1α in both MASH patients and wild-type mice fed a western diet (WD) inducing steatosis and fibrosis. We then generated a pure C57BL6/J strain loss of function mouse model in which Pgc-1α is selectively deleted in the liver and we fed these mice with a WD supplemented with sugar water that accurately mimics human MASH. RESULTS: We observed that the hepatic expression of Pgc-1α is strongly reduced in MASH, in both humans and mice. Moreover, the hepatic ablation of Pgc-1α promotes a considerable reduction of the hepatic mitochondrial respiratory capacity, setting up a bioenergetic harmful environment for liver diseases. Indeed, the lack of Pgc-1α decreases mitochondrial function and increases inflammation, fibrosis and oxidative stress in the scenario of MASH. Intriguingly, this profibrotic phenotype is not linked with obesity, insulin resistance and lipid disbalance. CONCLUSIONS: In a MASH model the hepatic ablation of Pgc-1α drives fibrosis independently from lipid and glucose metabolism. These results add a novel mechanistic piece to the puzzle of the specific and crucial role of mitochondrial function in MASH development.

Pivotal role of intestinal cholesterol and nuclear receptor LXR in metabolic liver steatohepatitis and hepatocarcinoma.

Hepatocellular carcinoma (HCC) incidence is continuously increasing worldwide, due to the rise of metabolic dysfunction-associated steatohepatitis (MASH) cases. Cholesterol is an essential driver of the metabolic dysregulations that promote HCC progression. Liver X Receptor (LXR) is a nuclear receptor best known for the regulation of lipid and cholesterol homeostasis, with a prominent function in the liver and in the intestine. Here, we aimed to explore whether modifications in intestinal lipid metabolism may contribute to the onset of HCC, particularly taking into account cholesterol metabolism and LXRs. To study the progression of MASH to HCC, we induced metabolic HCC in wild-type male mice and mice carrying an intestinal chronic activation of LXRα. Also, we analysed human hepatic transcriptome datasets. The increased consumption of fat and carbohydrates drives the intestinal activation of LXRα and accelerates the onset of the hepatic tumours. Chronic intestinal-specific activation of LXRα enhances HCC progression only in the presence of a high cholesterol intake. In HCC, despite the increased hepatic cholesterol content, LXR is not active, thus driving liver cancer development. Intriguingly, in line with these results in the mouse model, LXR transcriptome is also downregulated in human hepatocarcinoma and its expression level in liver tumours directly correlates with a decreased survival rate in patients. Overall, our findings establish the relevance of the intestine in influencing the susceptibility to MASH-HCC and point to intestinal LXRα activation as a driver of metabolic liver cancer in the presence of dietary cholesterol.

Fasting hyperglycaemia and fatty liver drive colorectal cancer: a retrospective analysis in 1145 patients.

BACKGROUND: Metabolic dysfunction-associated steatotic liver disease (MASLD) represents the hepatic manifestation of increased adiposopathy, whose pathogenetic features have been proposed as tumourigenic triggers for colorectal cancer (CRC). We aim to identify specific metabolic signatures involved in CRC development that may be used as non-invasive biomarkers, paving the way for specific and personalized strategies of CRC prevention and early detection. METHODS: We retrospectively assessed CRC onset during a time frame of 8 years in a cohort of 1145 out-patients individuals who had previously been evaluated for Metabolic Syndrome. RESULTS: 28 patients developed CRC. No association between CRC development and visceral and general obesity was detected, while baseline fasting plasma glucose (FPG) and non-invasive liver fibrosis scores were significantly higher in patients with CRC, compared to those who did not develop cancer. Liver steatosis and MASLD were more frequently diagnosed in patients who developed CRC compared to no cancer developers. Canonical correlations among metabolic biomarkers were not present in CRC developers, differently from no cancer group. In ROC analysis, FPG and non-invasive scores also showed good sensitivity and specificity in predicting colon cancer. We then calculated ORs for metabolic biomarkers, finding that higher FPG and non-invasive scores were associated with an increased risk of developing CRC. CONCLUSION: MASLD and increased FPG may play a role in the clinical background of CRC, bringing to light the fascinating possibility of a reversed gut-liver axis communication in the pathogenesis of CRC. Thus, the use of non-invasive scores of fatty liver may be helpful to predict the risk of CRC and serve as novel prognostic factors for prevention and therapeutic strategies.

RNA sequencing unravels novel L cell constituents and mechanisms of GLP-1 secretion in human gastric bypass-operated intestine.

AIMS/HYPOTHESIS: Roux-en-Y gastric bypass surgery (RYGB) frequently results in remission of type 2 diabetes as well as exaggerated secretion of glucagon-like peptide-1 (GLP-1). Here, we assessed RYGB-induced transcriptomic alterations in the small intestine and investigated how they were related to the regulation of GLP-1 production and secretion in vitro and in vivo. METHODS: Human jejunal samples taken perisurgically and 1 year post RYGB (n=13) were analysed by RNA-seq. Guided by bioinformatics analysis we targeted four genes involved in cholesterol biosynthesis, which we confirmed to be expressed in human L cells, for potential involvement in GLP-1 regulation using siRNAs in GLUTag and STC-1 cells. Gene expression analyses, GLP-1 secretion measurements, intracellular calcium imaging and RNA-seq were performed in vitro. OGTTs were performed in C57BL/6j and iScd1-/- mice and immunohistochemistry and gene expression analyses were performed ex vivo. RESULTS: Gene Ontology (GO) analysis identified cholesterol biosynthesis as being most affected by RYGB. Silencing or chemical inhibition of stearoyl-CoA desaturase 1 (SCD1), a key enzyme in the synthesis of monounsaturated fatty acids, was found to reduce Gcg expression and secretion of GLP-1 by GLUTag and STC-1 cells. Scd1 knockdown also reduced intracellular Ca2+ signalling and membrane depolarisation. Furthermore, Scd1 mRNA expression was found to be regulated by NEFAs but not glucose. RNA-seq of SCD1 inhibitor-treated GLUTag cells identified altered expression of genes implicated in ATP generation and glycolysis. Finally, gene expression and immunohistochemical analysis of the jejunum of the intestine-specific Scd1 knockout mouse model, iScd1-/-, revealed a twofold higher L cell density and a twofold increase in Gcg mRNA expression. CONCLUSIONS/INTERPRETATION: RYGB caused robust alterations in the jejunal transcriptome, with genes involved in cholesterol biosynthesis being most affected. Our data highlight SCD as an RYGB-regulated L cell constituent that regulates the production and secretion of GLP-1.

AST/ALT-to-platelet ratio (AARPRI) predicts gynaecological cancers: a 8-years follow-up study in 653 women.

Non-alcoholic fatty liver disease (NAFLD), specifically liver steatosis and fibrosis with steatohepatitis (NASH), is often associated with visceral adiposopathy, whose pathogenetic features have been proposed as tumorigenic triggers. We performed a prospective analysis in 653 metabolic women to reveal any conditions that may predict and concur to cancer development during a 8-years period of follow-up. Among clinical and biochemical variables, only AST and non-invasive liver fibrosis scores (AARPRI, APRI, FIB-4, mFIB4) significantly distinguished cancer-developer women (n = 62, 9.5%) from those who did not develop cancer (p < 0.001). In ROC analysis, these scores also showed good sensitivity and specificity in differentiating women who developed cancer (all p < 0.001). We then calculated OR for these indexes finding that increased AARPRI was associated with the highest risk (OR = 6, p < 0.001) of gynaecological cancers development. We further validated these cut-off values in women who had developed other types of cancer, confirming that AARPRI is able to identify the risk for cancer development (OR = 5, p < 0.001). Our findings support the hypothesis that NAFLD, more than obesity per se, is directly associated with the clinical and pathogenic metabolic scenario of gynaecological cancers and encourage the use of liver fibrosis indexes to detect risk of cancer onset in women. Preventing adiposopathy and NAFLD through lifestyle and therapies may represent an instrumental strategy for cancer prevention and/or co-treatment in oncology.

Intestinal Pgc1α ablation protects from liver steatosis and fibrosis.

Background & Aims: The gut-liver axis modulates the progression of metabolic dysfunction-associated steatotic liver disease (MASLD), a spectrum of conditions characterised by hepatic steatosis and a progressive increase of inflammation and fibrosis, culminating in metabolic dysfunction-associated steatohepatitis. Peroxisome proliferator-activated receptor-gamma coactivator 1α (Pgc1α) is a transcriptional co-regulator of mitochondrial activity and lipid metabolism. Here, the intestinal-specific role of Pgc1α was analysed in liver steatosis and fibrosis. Methods: We used a mouse model in which Pgc1α was selectively deleted from the intestinal epithelium. We fed these mice and their wild-type littermates a Western diet to recapitulate the major features of liver steatosis (after 2 months of diet) and metabolic dysfunction-associated steatohepatitis (after 4 months of diet). The chow diet was administered as a control diet. Results: In humans and mice, low expression of intestinal Pgc1α is inversely associated with liver steatosis, inflammation, and fibrosis. Intestinal disruption of Pgc1α impairs the transcription of a wide number of genes, including the cholesterol transporter Niemann-Pick C1-like 1 (Npc1l1), thus limiting the uptake of cholesterol from the gut. This results in a lower cholesterol accretion in the liver and a decreased production of new fatty acids, which protect the liver from lipotoxic lipid species accumulation, inflammation, and related fibrotic processes. Conclusions: In humans and mice, intestinal Pgc1α induction during Western diet may be another culprit driving hepatic steatosis and fibrosis. Here, we show that enterocyte-specific Pgc1α ablation protects the liver from steatosis and fibrosis by reducing intestinal cholesterol absorption, with subsequent decrease of cholesterol and de novo fatty acid accumulation in the liver. Impact and implications: Liver diseases result from several insults, including signals from the gut. Although the incidence of liver diseases is continuously increasing worldwide, effective drug therapy is still lacking. Here, we showed that the modulation of an intestinal coactivator regulates the liver response to a Western diet, by limiting the uptake of dietary cholesterol. This results in a lower accumulation of hepatic lipids together with decreased inflammation and fibrosis, thus limiting the progression of liver steatosis and fibrosis towards severe end-stage diseases.

Low HDL-cholesterol levels predict hepatocellular carcinoma development in individuals with liver fibrosis.

Background & Aims: Dysmetabolic conditions could drive liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD), increasing susceptibility to hepatocellular carcinoma (HCC). We therefore aimed to identify novel predictive biomarkers of HCC in patients with and without liver fibrosis. Methods: A total of 1,234 patients with putative metabolic conditions and NAFLD were consecutively assessed in our outpatient clinic. Clinical and biochemical data were recorded, and then liver ultrasonography was performed annually for 5 years to detect HCC onset. For the analysis, the population was first divided according to HCC diagnosis; then a further subdivision of those who did not develop HCC was performed based on the presence or absence of liver fibrosis at time 0. Results: Sixteen HCC cases were recorded in 5 years. None of our patients had been diagnosed with cirrhosis before HCC was detected. Compared to patients who did not develop HCC, those who did had higher liver transaminases and fibrosis scores at time 0 (p <0.001). In addition, they presented with increased glycated haemoglobin levels and lower 25-OH vitamin D levels (p <0.05). Intriguingly, patients with higher liver fibrosis scores who subsequently developed HCC had lower HDL-cholesterol (HDL-c) levels at time 0 (p <0.001). Furthermore, in the 484 patients presenting with lower HDL-c at baseline, we found that waist circumference, and then vitamin D and glycated haemoglobin levels, were significantly different in those who developed HCC, regardless of liver fibrosis (p <0.05). Conclusions: This study identifies HDL-c as a bona fide novel marker to predict HCC in patients with NAFLD. Increased waist circumference and deranged metabolic pathways represent additional predisposing factors among patients with low HDL-c, highlighting the importance of studying cholesterol metabolism and integrating clinical approaches with dietary regimens and a healthy lifestyle to prevent HCC. Impact and implications: Visceral adiposity and its associated conditions, such as chronic inflammation and insulin resistance, may play a pivotal role in hepatocellular carcinoma development in patients with non-alcoholic fatty liver disease. We provide new insights on the underlying mechanisms of its pathogenesis, shedding light on the involvement of low levels of "good" HDL-cholesterol. We recommend integrating dietary regimens and advice on healthy lifestyles into the clinical management of non-alcoholic fatty liver disease, with the goal of reducing the incidence of hepatocellular carcinoma.

Intestinal FXR Activation via Transgenic Chimera or Chemical Agonism Prevents Colitis-Associated and Genetically-Induced Colon Cancer.

The Farnesoid X Receptor (FXR) is the master regulator of Bile Acids (BA) homeostasis orchestrating their synthesis, transport and metabolism. Disruption of BA regulation has been linked to gut-liver axis diseases such as colorectal cancer (CRC). In this study, firstly we examined the role of constitutive activation of intestinal FXR in CRC; then we pre-clinically investigated the therapeutic potential of a diet enriched with a synthetic FXR agonist in two models of CRC (chemically-induced and genetic models). We demonstrated that mice with intestinal constitutive FXR activation are protected from AOM/DSS-induced CRC with a significant reduction of tumor number compared to controls. Furthermore, we evaluated the role of chemical FXR agonism in a DSS model of colitis in wild type (WT) and FXRnull mice. WT mice administered with the FXR activating diet showed less morphological alterations and decreased inflammatory infiltrates compared to controls. The FXR activating diet also protected WT mice from AOM/DSS-induced CRC by reducing tumors' number and size. Finally, we proved that the FXR activating diet prevented spontaneous CRC in APCMin/+ mice via an FXR-dependent modulation of BA homeostasis. Our results demonstrate that intestinal FXR activation prevented both inflammation- and genetically-driven colorectal tumorigenesis by modulating BA pool size and composition. This could open new avenues for the therapeutic management of intestinal inflammation and tumorigenesis.

Reduction in gut-derived MUFAs via intestinal stearoyl-CoA desaturase 1 deletion drives susceptibility to NAFLD and hepatocarcinoma.

Nonalcoholic fatty liver disease (NAFLD) is defined by a set of hepatic conditions ranging from steatosis to steatohepatitis (NASH), characterized by inflammation and fibrosis, eventually predisposing to hepatocellular carcinoma (HCC). Together with fatty acids (FAs) originated from adipose lipolysis and hepatic lipogenesis, intestinal-derived FAs are major contributors of steatosis. However, the role of mono-unsaturated FAs (MUFAs) in NAFLD development is still debated. We previously established the intestinal capacity to produce MUFAs, but its consequences in hepatic functions are still unknown. Here, we aimed to determine the role of the intestinal MUFA-synthetizing enzyme stearoyl-CoA desaturase 1 (SCD1) in NAFLD. We used intestinal-specific Scd1-KO (iScd1-/- ) mice and studied hepatic dysfunction in different models of steatosis, NASH, and HCC. Intestinal-specific Scd1 deletion decreased hepatic MUFA proportion. Compared with controls, iScd1-/- mice displayed increased hepatic triglyceride accumulation and derangement in cholesterol homeostasis when fed a MUFA-deprived diet. Then, on Western diet feeding, iScd1-/- mice triggered inflammation and fibrosis compared with their wild-type littermates. Finally, intestinal-Scd1 deletion predisposed mice to liver cancer. Conclusions: Collectively, these results highlight the major importance of intestinal MUFA metabolism in maintaining hepatic functions and show that gut-derived MUFAs are protective from NASH and HCC.

Platelets from patients with visceral obesity promote colon cancer growth.

Several studies highlighted the importance of platelets in the tumor microenvironment due to their ability to interact with other cell types such as leukocytes, endothelial, stromal and cancer cells. Platelets can influence tumor development and metastasis formation through several processes consisting of the secretion of growth factors and cytokines and/or via direct interaction with cancer cells and endothelium. Patients with visceral obesity (VO) are susceptible to pro-thrombotic and pro-inflammatory states and to development of cancer, especially colon cancer. These findings provide us with the impetus to analyze the role of platelets isolated from VO patients in tumor growth and progression with the aim to explore a possible link between platelet activation, obesity and colon cancer. Here, using xenograft colon cancer models, we prove that platelets from patients with visceral obesity are able to strongly promote colon cancer growth. Then, sequencing platelet miRNome, we identify miR-19a as the highest expressed miRNA in obese subjects and prove that miR-19a is induced in colon cancer. Last, administration of miR-19a per se in the xenograft colon cancer model is able to promote colon cancer growth. We thus elect platelets with their specific miRNA abundance as important factors in the tumor promoting microenvironment of patients with visceral obesity.

Enterocyte superoxide dismutase 2 deletion drives obesity.

Compelling evidence support an involvement of oxidative stress and intestinal inflammation as early events in the predisposition and development of obesity and its related comorbidities. Here, we show that deficiency of the major mitochondrial antioxidant enzyme superoxide dismutase 2 (SOD2) in the gastrointestinal tract drives spontaneous obesity. Intestinal epithelium-specific Sod2 ablation in mice induced adiposity and inflammation via phospholipase A2 (PLA2) activation and increased release of omega-6 polyunsaturated fatty acid arachidonic acid. Remarkably, this obese phenotype was rescued when fed an essential fatty acid-deficient diet, which abrogates de novo biosynthesis of arachidonic acid. Data from clinical samples revealed that the negative correlation between intestinal Sod2 mRNA levels and obesity features appears to be conserved between mice and humans. Collectively, our findings suggest a role of intestinal Sod2 levels, PLA2 activity, and arachidonic acid in obesity presenting new potential targets of therapeutic interest in the context of this metabolic disorder.

Monocyte-to-HDL Ratio (MHR) Predicts Vitamin D Deficiency in Healthy and Metabolic Women: A Cross-Sectional Study in 1048 Subjects.

Vitamin D deficiency is often linked with Metabolic Syndrome, both being more frequent with ageing and associated with an increase inflammatory state. Recently, monocytes-to-high density lipoprotein (HDL) ratio (MHR) has emerged as a powerful index to predict systemic inflammation. In this cross-sectional study, we investigated the association between circulating vitamin D level (25-OH vitamin D) and inflammatory status in a population of 1048 adult individuals. Our study reveals an inverse association between 25-OH vitamin D levels and MHR in the overall population. When the population is stratified by gender, waist circumference, and body mass index (BMI), we observed that while in men this relation is strongly significative only in condition of central obesity, in women a lifelong negative correlation exists between circulating 25-OH vitamin D and MHR and it is independent of the metabolic status. These observations underscore the relevance of circulating biomarkers such as MHR in the prediction of systemic inflammatory conditions sustained by vitamin D deficiency also in healthy and young women.

Adhesion of Platelets to Colon Cancer Cells Is Necessary to Promote Tumor Development in Xenograft, Genetic and Inflammation Models.

Platelets represent the linkage between tissue damage and inflammatory response with a putative role in tumorigenesis. Given the importance of the microenvironment in colon cancer development, we elucidated the eventual role of platelets-cancer cells crosstalk in in vivo colon cancermodels. To evaluate the involvement of platelets in intestinal tumorigenesis, we first analyzed if the ablation of ß-integrin P-selectin that drives platelets-cell adhesion, would contribute to platelets-colon cancer cell interaction and drive cancer progression. In a xenograft tumor model, we observed that when tumors are inoculated with platelets, the ablation of P-selectin significantly reduced tumor growth compared to control platelets. Furthermore, in genetic models, as well as in chronic colitis-associated colorectal carcinogenesis, P-selectin ablated mice displayed a significant reduction in tumor number and size compared to control mice. Taken together, our data highlights the importance of platelets in the tumor microenvironment for intestinal tumorigenesis. These results support the hypothesis that a strategy aimed to inhibit platelets adhesion to tumor cells are able to block tumor growth and could represent a novel therapeutic approach to colon cancer treatment.

Visceral Adiposity and Cancer: Role in Pathogenesis and Prognosis.

The prevalence of being overweight and obese has been expanded dramatically in recent years worldwide. Obesity usually occurs when the energetic introit overtakes energy expenditure from metabolic and physical activity, leading to fat accumulation mainly in the visceral depots. Excessive fat accumulation represents a risk factor for many chronic diseases, including cancer. Adiposity, chronic low-grade inflammation, and hyperinsulinemia are essential factors of obesity that also play a crucial role in tumor onset. In recent years, several strategies have been pointed toward boundary fat accumulation, thus limiting the burden of cancer attributable to obesity. While remodeling fat via adipocytes browning seems a tempting prospect, lifestyle interventions still represent the main pathway to prevent cancer and enhance the efficacy of treatments. Specifically, the Mediterranean Diet stands out as one of the best dietary approaches to curtail visceral adiposity and, therefore, cancer risk. In this Review, the close relationship between obesity and cancer has been investigated, highlighting the biological mechanisms at the basis of this link. Finally, strategies to remodel fat, including browning and lifestyle interventions, have been taken into consideration as a major perspective to limit excess body weight and tumor onset.

PGC-1s in the Spotlight with Parkinson's Disease.

Parkinson's disease is one of the most common neurodegenerative disorders worldwide, characterized by a progressive loss of dopaminergic neurons mainly localized in the substantia nigra pars compacta. In recent years, the detailed analyses of both genetic and idiopathic forms of the disease have led to a better understanding of the molecular and cellular pathways involved in PD, pointing to the centrality of mitochondrial dysfunctions in the pathogenic process. Failure of mitochondrial quality control is now considered a hallmark of the disease. The peroxisome proliferator-activated receptor gamma coactivator 1 (PGC-1) family acts as a master regulator of mitochondrial biogenesis. Therefore, keeping PGC-1 level in a proper range is fundamental to guarantee functional neurons. Here we review the major findings that tightly bond PD and PGC-1s, raising important points that might lead to future investigations.

let-7e downregulation characterizes early phase colonic adenoma in APCMin/+ mice and human FAP subjects.

The crypt-villus axis represents the essential unit of the small intestine, which integrity and functions are fundamental to assure tissue and whole-body homeostasis. Disruption of pathways regulating the fine balance between proliferation and differentiation results in diseases development. Nowadays, it is well established that microRNAs (miRNAs) play a crucial role in the homeostasis maintenance and perturbation of their levels may promote tumor development. Here, by using microarray technology, we analysed the miRNAs differentially expressed between the crypt and the villus in mice ileum. The emerged miRNAs were further validated by Real Time qPCR in mouse model (ApcMin/+), human cell lines and human tissue samples (FAP) of colorectal cancer (CRC). Our results indicated that miRNAs more expressed in the villi compartment are negatively regulated in tumor specimens, thus suggesting a close association between these microRNAs and the differentiation process. Particularly, from our analysis let-7e appeared to be a promising target for possible future therapies and a valuable marker for tumor staging, being upregulated in differentiated cells and downregulated in early-stage colonic adenoma samples.

Another One Bites the Gut: Nuclear Receptor LRH-1 in Intestinal Regeneration and Cancer.

The process of self-renewal in normal intestinal epithelium is characterized by a fine balance between proliferation, differentiation, migration, and cell death. When even one of these aspects escapes the normal control, cellular proliferation and differentiation are impaired, with consequent onset of tumorigenesis. In humans, colorectal cancer (CRC) is the main pathological manifestation of this derangement. Nowadays, CRC is the world's fourth most deadly cancer with a limited survival after treatment. Several conditions can predispose to CRC development, including dietary habits and pre-existing inflammatory bowel diseases. Given their extraordinary ability to interact with DNA, it is widely known that nuclear receptors play a key role in the regulation of intestinal epithelium, orchestrating the expression of a series of genes involved in developmental and homeostatic pathways. In particular, the nuclear receptor Liver Receptor Homolog-1 (LRH-1), highly expressed in the stem cells localized in the crypts, promotes intestine cell proliferation and renewal in both direct and indirect DNA-binding manner. Furthermore, LRH-1 is extensively correlated with diverse intestinal inflammatory pathways. These evidence shed a light in the dynamic intestinal microenvironment in which increased regenerative epithelial cell turnover, mutagenic insults, and chronic DNA damages triggered by factors within an inflammatory cell-rich microenvironment act synergistically to favor cancer onset and progression.

Transcriptional Regulation of Metabolic Pathways via Lipid-Sensing Nuclear Receptors PPARs, FXR, and LXR in NASH.

Nonalcoholic fatty liver disease comprises a wide spectrum of liver injuries from simple steatosis to steatohepatitis and cirrhosis. Nonalcoholic steatohepatitis (NASH) is defined when liver steatosis is associated with inflammation, hepatocyte damage, and fibrosis. A genetic predisposition and environmental insults (ie, dietary habits, obesity) are putatively responsible for NASH progression. Here, we present the impact of the lipid-sensing nuclear receptors in the pathogenesis and treatment of NASH. In detail, we discuss the pros and cons of the putative transcriptional action of the fatty acid sensors (peroxisome proliferator-activated receptors), the bile acid sensor (farnesoid X receptor), and the oxysterol sensor (liver X receptors) in the pathogenesis and bona fide treatment of NASH.

Increased risk of acute liver failure by pain killer drugs in NAFLD: Focus on nuclear receptors and their coactivators.

Non-alcoholic fatty liver disease (NAFLD) is a global condition characterized by an accumulation of lipids in the hepatocytes. NAFLD ranges from simple steatosis, a reversible and relatively benign condition, to fibrosis with non-alcoholic steatohepatitis (NASH), potentially leading to cirrhosis and hepatocarcinoma. NAFLD can increase the susceptibility to severe liver injury with eventual acute liver failure induced by specific hepatotoxic drugs, including acetaminophen (APAP), which is commonly used as analgesic and antipyretic. Although several animal models have been used to clarify the predisposing role of hepatic steatosis to APAP intoxication, the exact mechanism is still not clear. Here, we shed a light into the association between NAFLD and APAP toxicity by examining the peculiar role of nuclear receptor peroxisome proliferator-activated receptor α (PPARα) and coactivator peroxisome proliferator-activated receptor gamma coactivator 1-ß (PGC-1ß) in driving fatty acid metabolism, inflammation and mitochondria redox balance. The knowledge of the mechanism that exposes patients with NAFLD to higher risk of acute liver failure by pain killer drug is the first step to eventually claim for a reduction of the maximal diurnal dose of APAP for subjects with liver steatosis.