Fibrosing NASH: on being a blind man in a dark room looking for a black cat (that isn't there)

Breakthroughs in therapies for NASH and remaining challenges

Initially a condition that received limited recognition and whose clinical impact was controversial, non-alcoholic steatohepatitis (NASH) has become a leading cause of chronic liver disease. Although there are no approved therapies, major breakthroughs, which will be reviewed here, have paved the way for future therapeutic successes. The unmet medical need in NASH is no longer disputed, and progress in the understanding of its pathogenesis has resulted in the identification of many pharmacological targets. Key surrogate outcomes for therapeutic trials are now accepted by regulatory agencies, thus creating a path for drug registration. A set of non-invasive measurements enabled early-stage trials to be conducted expeditiously, thus providing early indications on the biological and possibly clinical actions of therapeutic candidates. This generated efficacy results for a number of highly promising compounds that are now in late-stage development. Intense research aimed at further improving the assessment of histological endpoints and in developing non-invasive predictive biomarkers is underway. This will help improve the design and feasibility of successful trials, ultimately providing patients with therapeutic options that can change the course of the disease.

Too much medicine: overdiagnosis and overtreatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is now the most common cause of liver disease. This remarkable rise in prevalence over the past 20 years is largely through the recognition of fatty liver in the absence of excessive alcohol consumption as a disease. The natural history of NAFLD is incompletely understood, and although a small proportion of individuals with NAFLD will develop complications of liver disease, most will not. This raises the prospect of widespread overdiagnosis of NAFLD. Clinical practice guidelines from the European specialist societies representing hepatology, endocrinology, and obesity endorse screening for NAFLD in at-risk groups, and this further increases the likelihood of overdiagnosis and consequent overtreatment through false-positive testing. Predictable outcomes of overdiagnosis include physical harms through investigation and treatment, and psychosocial harms through disease labelling. Prospective studies are required to better understand both the benefits and risks associated with an early diagnosis of NAFLD.

ADAMTS13 deficiency promotes microthrombosis in a murine model of diet-induced liver steatosis

ADAMTS13 cleaves ultralarge multimeric von Willebrand Factor (VWF), thereby preventing formation of platelet-rich microthrombi. ADAMTS13 is mainly produced by hepatic stellate cells, and numerous studies have suggested a functional role of ADAMTS13 in the pathogenesis of liver diseases. The aim of our study was to investigate a potential role of ADAMTS13 in formation of hepatic microthrombi and development of non-alcoholic steatohepatitis (NASH), and furthermore to evaluate whether plasmin can compensate for the absence of ADAMTS13 in removal of thrombi. Therefore, we used a model of high-fat diet-induced steatosis in Adamts13 deficient (Adamts13^-/-) and wild-type (WT) control mice. Microthrombi were more abundant in the liver of obese Adamts13^-/- as compared to obese WT or to lean Adamts13^-/- mice. Obese Adamts13^-/- mice displayed lower platelet counts and higher prevalence of ultra-large VWF multimers. Hepatic plasmin-α2-antiplasmin complex levels were comparable for obese WT and Adamts13^-/- mice and were lower for lean Adamts13^-/- than WT mice, not supporting marked activation of the fibrinolytic system. High fat diet feeding, as compared to normal chow, resulted in enhanced liver triglyceride levels for both genotypes (p < 0.0001) and steatosis (p < 0.0001 for WT mice, p = 0.002 for Adamts13^-/- mice) without differences between the genotypes. Expression of markers of inflammation, oxidative stress, steatosis and fibrosis was affected by diet, but not by genotype. Thus, our data confirm that obesity promotes NASH, but do not support a detrimental role of ADAMTS13 in its development. However, Adamts13 deficiency in obese mice promotes hepatic microthrombosis, whereas a compensatory role of plasmin in removal of microthrombi in the absence of ADAMTS13 could not be demonstrated.

Nonalcoholic fatty liver disease: update on pathogenesis, diagnosis, treatment and the role of S-adenosylmethionine

Nonalcoholic fatty liver disease (NAFLD) is currently the most common liver disease worldwide affecting over one-third of the population in the U.S. It has been associated with obesity, type 2 diabetes, hyperlipidemia, and insulin resistance and is initiated by the accumulation of triglycerides in hepatocytes. Isolated hepatic steatosis (IHS) remains a benign process, while a subset develops superimposed inflammatory activity and progression to nonalcoholic steatohepatitis (NASH) with or without fibrosis. However, the molecular mechanisms underlying NAFLD progression are not completely understood. Liver biopsy is still required to differentiate IHS from NASH as easily accessible noninvasive biomarkers are lacking. In terms of treatments for NASH, pioglitazone, vitamin E, and obeticholic acid have shown some benefit. All of these agents have potential complications associated with long-term use. Nowadays, a complex hypothesis suggests that multiple parallel hits are involved in NASH development. However, the 'key switch' between IHS and NASH remains to be discovered. We have recently shown that knocking out enzymes involved in S-adenosylmethionine (SAMe) metabolism, the main biological methyl donor in humans that is abundant in the liver, will lead to NASH development in mice. This could be due to the fact that a normal SAMe level is required to establish the proper ratio of phosphatidylethanolamine to phosphatidylcholine that has been found to be important in NAFLD progression. New data from humans have also suggested that these enzymes play a role in the pathogenesis of NAFLD and that some of SAMe cycle metabolites may serve as noninvasive biomarkers of NASH. In this review, we discuss the evidence of the role of SAMe in animal models and humans with NAFLD and how studying this area may lead to the discovery of new noninvasive biomarkers and possibly personalized treatment for NASH.

Antepartum obstetrical complications associated with obesity

Obesity is a major risk factor for many obstetrical complications, including pre-eclampsia, gestational diabetes, indicated preterm birth, macrosomia, and stillbirth. Clinicians should be aware of the unique obstetrical management considerations related to obesity, including recommendations for alterations in prenatal care. In addition, obese gravidas commonly have underlying medical conditions that can impact pregnancy and must be appreciated to optimize care. Obese women should be educated about these risks, ideally before pregnancy. Awareness of the complications that can arise for these women and potential changes in management offer opportunities to improve both prenatal and lifelong health.

Noninvasive tools to assess hepatic fibrosis: ready for prime time?

Often regarded as the gold standard for fibrosis assessment, liver biopsy carries associated risks; however, it is less than ideal. The need for noninvasive assessment of hepatic fibrosis for disease staging, prognosis, progression, and treatment response is clear. Advances in serologic testing and conventional imaging techniques have reduced the need for liver biopsy. Areas of research include defining cutoff values for specific diseases, further head-to-head comparisons of noninvasive modalities, examination of algorithms using both serum markers and imaging, and the cost-effectiveness of these various tests for diagnostic as well as screening purposes.