A significant body of evidence now forces us to rethink the causes of NASH. Once thought to be a disease caused by triglyceride accumulation in hepatocytes with subsequent oxidant stress and lipid ...peroxidation causing inflammation and fibrosis, new data from animal studies and a limited number of human studies now provide convincing evidence that triglyceride accumulation does not cause insulin resistance or cellular injury in the liver. The lipotoxic liver injury hypothesis for the pathogenesis of NASH suggests that we need to focus our therapeutic efforts on reducing the burden of fatty acids going to the liver or being synthesized in the liver. This can be accomplished by improving insulin sensitivity at the level of adipose tissue to prevent inappropriate peripheral lipolysis and by preventing unnecessary de novo lipogenesis in the liver. Excess carbohydrates are the major substrates for de novo lipogenesis, and thus, reducing carbohydrate consumption through dietary changes and increasing muscle glucose uptake through exercise remain important cornerstones of treatment and prevention of lipotoxic liver injury, a disease hitherto called NASH.
Nonalcoholic fatty liver disease (NAFLD) is a spectrum comprised of isolated steatosis, nonalcoholic steatohepatitis (NASH), advanced fibrosis, and cirrhosis. The majority of NAFLD subjects do not ...have NASH and do not carry a significant risk for liver‐related adverse outcomes (cirrhosis and mortality). Globally, the prevalence of NAFLD is approximately 25%. In Asia, a gradient of high to low prevalence rates is noted from urban to rural areas. Given the prevalence of NAFLD, the clinical and economic burden of NAFLD and NASH can be substantial. With increasing recognition of NASH as an important liver disease, the diagnosis of NASH still requires a liver biopsy that is suboptimal. Although liver biopsy is the most accurate modality to diagnose and stage the severity of NASH, this method suffers from being invasive, costly, associated with potential complications, and plagued with interobserver variability of individual pathological features. A number of noninvasive modalities to diagnose NASH and stage liver fibrosis are being developed. These modalities include predictive models (NAFLD fibrosis score) and serum biomarkers such as enhanced liver fibrosis (ELF). Other tests are based on radiological techniques, such as transient elastography (TE) or magnetic resonance elastography (MRE), which are used to estimate liver stiffness as a potential surrogate of hepatic fibrosis. Although a dynamic field of research, most of these diagnostic modalities have area under the curve ranging between 0.76 and 0.90%, with MRE having the best predictive performance. In summary, developing safe and easily accessible noninvasive modalities to accurately diagnose and monitor NASH and associated fibrosis is of utmost importance in clinical practice and clinical research. These tests are not only important to risk stratify subjects at the greatest risk for progressive liver disease, but also to serve as appropriate surrogate endpoints for therapeutic clinical trials of NASH. (Hepatology 2018;68:349‐360).
Nonalcoholic fatty liver disease (NAFLD) and its progressive form non‐alcoholic steatohepatitis (NASH), are rapidly becoming among the top causes of cirrhosis, hepatocellular carcinoma, and ...indications for liver transplantation. Other than lifestyle modification through diet and exercise, there are currently no other approved treatments for NASH/NAFLD. Although weight loss can be effective, it is difficult to achieve and sustain. In contrast, bariatric surgery can improve metabolic conditions associated with NAFLD, and has been shown to improve liver histology. To have approved regimens for the treatment of NASH/NAFLD, several issues must be addressed. First, all stakeholders must agree on the most appropriate clinical trial endpoints for NASH. Currently, resolution of NASH (without worsening fibrosis) or reduction of fibrosis stage (without worsening NASH) are the accepted endpoints by the regulatory authorities. It is important to recognize the prognostic implication of histologic features of NASH. In this context, although histologic NASH has been associated with advanced fibrosis, it is not an independent predictor of long‐term mortality. In contrast, there are significant data to suggest that fibrosis stage is the only robust and independent predictor of liver‐related mortality. In addition to the primary endpoints, several important secondary endpoints, including noninvasive biomarkers, long‐term outcomes, and patient‐reported outcomes must be considered. In 2018, a few phase 3 clinical trials for the treatment of NASH have been initiated. Additionally, a number of phase 2a and 2b clinical trials targeting different pathogenic pathways in NASH are in the pipeline of emerging therapies. Conclusion: Over the next 5 years, some of these regimens are expected to provide potential new treatment options for patients with NASH/NAFLD. (Hepatology 2018;68:361‐371)
The role of liver biopsy in NASH has evolved along with the increased recognition of the significance of this disease, and the unmet medical need it presents. Drug development and clinical trials are ...rapidly growing, as are noninvasive tests for markers of steatosis, inflammation, injury, and fibrosis. Liver biopsy evaluation remains necessary for both drug development and clinical trials as the most specific means of diagnosis and patient identification for appropriate intervention. This White Paper, sponsored by the American Association for the Study of Liver Disease NASH Task Force, is a focused review of liver biopsy evaluation in fatty liver disease in subjects with presumed NAFLD for practicing clinical hepatologists and pathologists. The goal is to provide succinct and specific means for reporting the histopathologic elements of NASH, distinguishing NASH from nonalcoholic fatty liver without steatohepatitis, and from alcohol‐associated steatohepatitis when possible. The discussion includes the special situations of NASH in advanced fibrosis or cirrhosis, and in the pediatric population. Finally, there is discussion of semiquantitative methods of evaluation of lesions of “disease activity” and fibrosis. Tables are presented for scoring and a suggested model for final reporting. Figures are presented to highlight the histopathologic elements of NASH.
Vibration‐controlled transient elastography estimates liver stiffness measurement (LSM) and controlled attenuation parameter (CAP), which are noninvasive assessments of hepatic fibrosis and ...steatosis, respectively. However, prior vibration‐controlled transient elastography studies reported high failure rates in patients with nonalcoholic fatty liver disease. We examined the performance characteristics of the FibroScan 502 Touch with two probes, medium (M+) and extra large (XL+), in patients with nonalcoholic fatty liver disease in a multicenter setting. A total of 1,696 exams were attempted in 992 patients (body mass index, 33.6 ± 6.5 kg/m2) with histologically confirmed nonalcoholic fatty liver disease. Simultaneous assessment of LSM and CAP was performed using the FibroScan 502 Touch with an automatic probe selection tool. Testing was conducted twice in patients by either a single operator (87%) or two operators (13%). Failure was defined as the inability to obtain a valid examination. An examination was considered unreliable if LSM interquartile range/median was >30%. Significant disagreement between two readings was defined as >95% limits of agreement between two readings. A total of 1,641 examinations yielded valid results with a failure rate of 3.2% (55/1,696). The proportion of unreliable scans for LSM was 3.9%. The proportion of unreliable scans with operator experience in the top quartile (≥59 procedures) was significantly lower than that in the lower three quarters combined (1.6% versus 4.7%, P = 0.02 by Fisher's exact test). The significant disagreement between first and second readings for LSM and CAP when obtained back to back was 18% and 11%, respectively. Conclusion: Vibration‐controlled transient elastography for estimation of LSM and CAP can be successfully deployed in a multicenter setting with low failure (3.2%) and high reliability (>95%) rates and high reproducibility. (Hepatology 2018;67:134‐144).
Therapeutic Landscape for NAFLD in 2020 Neuschwander-Tetri, Brent A.
Gastroenterology (New York, N.Y. 1943),
20/May , Letnik:
158, Številka:
7
Journal Article
Recenzirano
Lifestyle modifications focused on healthy eating and regular exercise are the primary recommendations for patients with nonalcoholic steatohepatitis (NASH). However, for multiple societal, ...psychological, physical, genetic, and epigenetic reasons, the ability of people to adopt and sustain such changes is challenging and typically not successful. To end the epidemic of NASH and prevent its complications, including cirrhosis and hepatocellular carcinoma, pharmacological interventions are now being evaluated in clinical trials. Treatments include drugs targeting energy intake, energy disposal, lipotoxic liver injury, and the resulting inflammation and fibrogenesis that lead to cirrhosis. It is likely that patients develop the phenotype of NASH by multiple mechanisms, and thus the optimal treatments of NASH will likely evolve to personalized therapy once we understand the mechanistic underpinnings of NASH in each patient. Reviewed here is the treatment landscape in this rapidly evolving field with an emphasis on drugs in Phase 2 and Phase 3 trials.
Non-alcoholic fatty liver disease has emerged a major challenge because of it prevalence, difficulties in diagnosis, complex pathogenesis, and lack of approved therapies. As the burden of hepatitis C ...abates over the next decade, non-alcoholic fatty liver disease will become the major form of chronic liver disease in adults and children and could become the leading indication for liver transplantation. This overview briefly summarizes the most recent data on the pathophysiology, diagnosis, and treatment of non-alcoholic fatty liver disease. Ongoing clinical trials are focused on an array of disease mechanisms and reviewed here are how these treatments fit into the current paradigm of substrate overload lipotoxic liver injury. Many of the approaches are directed at downstream events such as inflammation, injury and fibrogenesis. Addressing more proximal processes such as dysfunctional satiety mechanisms and inappropriately parsimonious energy dissipation are potential therapeutic opportunities that if successfully understood and exploited would not only address fatty liver disease but also the other components of the metabolic syndrome such as obesity, diabetes and dyslipidemia.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
There has been a rise in the prevalence of nonalcoholic fatty liver disease (NAFLD), paralleling a worldwide increase in diabetes and metabolic syndrome. NAFLD, a continuum of liver abnormalities ...from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH), has a variable course but can lead to cirrhosis and liver cancer. Here we review the pathogenic and clinical features of NAFLD, its major comorbidities, clinical progression and risk of complications and in vitro and animal models of NAFLD enabling refinement of therapeutic targets that can accelerate drug development. We also discuss evolving principles of clinical trial design to evaluate drug efficacy and the emerging targets for drug development that involve either single agents or combination therapies intended to arrest or reverse disease progression.
Hepatocellular injury and inflammation are believed to be the primary drivers of fibrogenesis that ultimately lead to cirrhosis in patients with nonalcoholic steatohepatitis (NASH). This study sought ...associations between observed improvements in fibrosis with improvement in specific histologic features, nonalcoholic fatty liver disease activity score (NAS) ≥2, diagnostic category, and primary histologically based outcomes of two adult NASH treatment trials. The primary outcome for the study was fibrosis improvement from baseline to end of treatment, defined as a 1‐point or more improvement in fibrosis stage. This is a retrospective analysis of biopsy data collected from the NASH Clinical Research Network Pathology Committee of Pioglitazone versus Vitamin E versus Placebo for the Treatment of Nondiabetic Patients with NASH Trial (PIVENS) and Farnesoid X Receptor Ligand Obeticholic Acid in NASH Treatment Trial (FLINT) baseline and final biopsies. Treatment group–adjusted univariable and multivariable logistic regression models related improvement in fibrosis to improvements in other histologic variables, resolution of steatohepatitis, and improvement in the NAS ≥2. In PIVENS 221 subjects had baseline and 96‐week biopsies, and in FLINT 200 subjects had baseline and 72‐week biopsies. Improvement in fibrosis was found in 38% of PIVENS and 29% of FLINT biopsies; fibrosis improvement was more likely in treated than placebo subjects in both studies. Controlling for treatment group, fibrosis improvement was associated most strongly with resolution of NASH (PIVENS, odds ratio OR, 3.9; 95% confidence interval CI 2.0‐7.6; P < 0.001; FLINT, OR, 8.0; 95% CI 3.1‐20.9; P < 0.001), and improved NAS by ≥2 (PIVENS, OR, 2.4; 95% CI 1.3‐4.3; P = 0.003; FLINT, OR, 4.2; 95% CI 2.1‐8.3; P < 0.001). Improvement in histologic features associated with improved fibrosis for both studies included steatosis, ballooning, Mallory‐Denk bodies, and portal, but not lobular, inflammation. Conclusion: These findings support a strong link between histologic resolution of steatohepatitis with improvement in fibrosis in NASH.
Nonalcoholic steatohepatitis (NASH) is an important cause of liver‐related morbidity and mortality. There are no approved therapies, and the results of clinical trials have been difficult to compare ...due to inconsistent definitions of relevant disease parameters in patients with NASH. The natural course of the disease has not been rigorously characterized, particularly with respect to the contributions of underlying obesity, type 2 diabetes, and other comorbidities and the treatments provided for these comorbidities. Efforts to perform analyses of pooled data are limited by heterogeneous case definitions used across studies to define disease states. There remains a major unmet need in the field to develop standardized definitions for populations for interventional trials. Such definitions are expected to impact how endpoints for clinical trials are constructed. The Liver Forum is a multistakeholder effort including US and European regulatory agencies, academic investigators, professional and patient representative organizations, and industry to catalyze therapeutic development for NASH by developing potential solutions to barriers to development. The Case Definitions Working Group was established by The Liver Forum to evaluate the validity of case definitions for populations to be included in clinical trials for NASH from a regulatory science perspective. Based on such analyses, specific recommendations are provided noting the strengths and weaknesses of the case definitions along with knowledge gaps that require additional study. (Hepatology 2018;67:2001‐2012)
PDF
