Mechanisms and disease consequences of nonalcoholic fatty liver disease

Cell, Journal Year: 2021, Volume and Issue: 184(10), P. 2537 - 2564

Published: May 1, 2021

Language: Английский

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Fibrosis: from mechanisms to medicines

Nature, Journal Year: 2020, Volume and Issue: 587(7835), P. 555 - 566

Published: Nov. 25, 2020

Language: Английский

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AASLD Practice Guidance on the clinical assessment and management of nonalcoholic fatty liver disease

Hepatology, Journal Year: 2023, Volume and Issue: 77(5), P. 1797 - 1835

Published: Feb. 2, 2023

PREAMBLE The study of NAFLD has intensified significantly, with more than 1400 publications since 2018, when the last American Association for Study Liver Diseases (AASLD) Guidance document was published.1 This new AASLD reflects many advances in field pertinent to any practitioner caring patients and emphasizes noninvasive risk stratification therapeutics. A separate guideline focused on management context diabetes been written jointly by Clinical Endocrinology AASLD.2 Given significant growth pediatric NAFLD, it will not be covered here allow a robust discussion diagnosis upcoming Pediatric Guidance. "Guidance" differs from "Guideline" that is bound Grading Recommendations, Assessment Development Evaluation system. Thus, actionable statements rather formal recommendations are provided herein. highest available level evidence used develop these statements, and, where high-level available, expert opinion guidance inform clinical practice. Key points highlight important concepts relevant understanding disease its management. most profound practice biomarkers Biomarkers tests (NITs) can clinically either exclude advanced diseases or identify those high probability cirrhosis.3,4 NIT "cut points" vary populations studied, underlying severity, setting. Those proposed this meant aid decision-making clinic interpreted isolation. Identifying "at-risk" NASH (biopsy-proven stage 2 higher fibrosis) recent area interest. Although definitive staging remain linked histology, tools now assess likelihood fibrosis, predict progression decompensation, make decisions, some degree, response treatment. There an ongoing debate over nomenclature fatty liver disease, which had finalized at time published. At culmination rigorous consensus process, intended change advance without negative impact awareness, trial endpoints, drug development/approval process. Furthermore, should emergence newly recognized subtypes address heterogeneity, including role alcohol, therapy. Input central all stages process ensure minimization nomenclature-related stigma. DEFINITIONS overarching term includes grades refers population ≥5% hepatocytes display macrovesicular steatosis absence readily identified alternative cause (eg, medications, starvation, monogenic disorders) individuals who drink little no alcohol (defined as < 20 g/d women <30 men). spectrum NAFL, characterized hepatic may accompanied mild inflammation, NASH, additionally presence inflammation cellular injury (ballooning), finally cirrhosis, bands fibrous septa leading formation cirrhotic nodules, earlier features longer fully appreciated biopsy. UPDATE ON EPIDEMIOLOGY AND NATURAL HISTORY prevalence rising worldwide parallel increases obesity metabolic comorbid (insulin resistance, dyslipidemia, obesity, hypertension).5,6 adults estimated 25%–30% general population7–9 varies setting, race/ethnicity, geographic region studied but often remains undiagnosed.10–14 associated economic burden attributable substantial.15–17 challenging determine certainty; however, 14% asymptomatic undergoing colon cancer screening.14 also highlights publication prior prospective study,18 fibrosis (stage increased >2-fold. supported projected rise 2030, defined bridging (F3) compensated cirrhosis (F4), increase disproportionately, mirroring doubling NASH.5,19 As such, incidence HCC, death related likewise expected 2- 3-fold 2030.5 further, NASH-related already indication transplantation >65 years age par overall.20–22 Natural history Data meta-analyses pooled studies demonstrate steatohepatitis primary predictors progression.23–25 collinearity between induces makes independent contribution adverse outcomes multivariable analyses.26,27 determinant outcomes, liver-related morbidity mortality nonhepatic malignancy observed even initial biopsy.25 Nevertheless, least (F2), referred have demonstrably mortality.24,28 Fibrosis influenced factors such severity genomic profile, environmental factors. meta-analysis placebo-treated 35 trials found minimal progression, suggesting nonpharmacologic (frequent visits/monitoring, dietary lifestyle counseling, changes) reduce progression.29 An cohorts longitudinal paired biopsies30 demonstrated rate one per 7 versus 14 NAFL.30 determined biopsy noninvasively, because changes require biannual screening HCC well varices monitoring signs symptoms decompensation.31,32 Among decompensation ranges 3% 20% year.12,33–35 common causes overall cardiovascular (CVD) malignancy, followed disease. amount histologically strongly development death.24,26,36,37 Bridging exponentially greater fibrosis.23,24,35 In 1773 patients, all-cause 0–2 0.32 100 person-years, compared 0.89 person-years 1.76 cirrhosis. After correcting multiple factors, (HR, 6.8; 95% CI, 2.2–21.3).35 Cirrhosis regression 6-fold reduction events trials.38Key points: Patients F2–4 considered NASH. rates depending baseline genetic, individual environmental, determinants. CVD malignancies fibrosis; predominates fibrosis. MOLECULAR CELLULAR PATHOGENESIS NAFL substantially govern supply disposition acids, diacylglycerols, ceramides, cholesterol, phospholipids, other intrahepatic lipids. Energy oversupply limited adipose tissue expansion contribute insulin resistance disease.39 When energy intake exceeds needs disposal capacity, carbohydrates, form sugars fructose, sucrose, glucose), drive accumulation fat de novo lipogenesis (DNL).40,41 substantial interindividual heterogeneity DNL among NAFLD.42,43 addition, type consumed plays saturated unsaturated consumption (Figure 1).44–46FIGURE 1: Pathogenic drivers therapeutic targets. Overview major mechanisms lead phenotype consequences, leveraged therapeutically. Not shown areas genetic polymorphisms play modifying types fats [saturated vs. polyunsaturated acid (PUFA)], gut microbiome, uric acid, periodic hypoxia (sleep apnea) influence pathways. driver adipocytes their ability store triglyceride inducing cell stress exceeded, activates inflammatory pathways resistance. Understanding facilitates rational therapies Specific sites intervention might prevent resolve include interventions modulate food portion sizes, bariatric surgery, satiety regulators), exercise, thermogenesis), improve adipocyte sensitivity [eg, peroxisome proliferator-activated receptor (PPAR)γ ligands], impair acetyl-coenzyme carboxylase synthase inhibitors), oxidative metabolism (PPARα ligands thyroid hormone beta agonists), attenuate death, fibrogenesis. Therapeutic agents affecting throughout body potential beneficial effects peptide analogs fibroblast factor-19, factor-21, glucagon-like peptide-1, gastric inhibitory peptide, glucagon) nuclear drugs target PPARα, PPARδ, PPARγ, β, farnesoid X receptor. Abbreviations: ER, endoplasmic reticulum; CVD, disease.Insulin nearly universal present liver, tissue, muscle.47 Adipose release free acids (lipolysis) fasting state48 worsens NASH.39,47,49 Important frequency intensity activation brown energy-consuming thermogenic phenotype, counterregulatory diminish reductions calorie intake.39,50 desire engage regular exercise personal, community, corporate, societal, legislative thus roles contributing pathophysiology impeded diagnostic therapeutics.51 driven substrate overload heavily impacting hepatocyte lipid handling.43 Genetic I148M polymorphism PNPLA3 impairs lipolysis droplets,52 proteins transmembrane 6 superfamily member (TM6SF2), cholesterol metabolism,53 MBOAT7, influences phospholipid metabolism.54 Recently, loss-of-function variants HSD17B13, gene encodes enzyme localizes droplets hepatocytes, protection against progressive HCC.55 Rare mutations CIDEB, protein needed DNL,56 protective.57 host additional review beyond scope guidance, activity progression.49,58–63 Additional production, exposure products derived perhaps low magnesium levels, phenotype.64–69 Transcriptomic profiling large further our progression.70,71 lipotoxic recruitment resident macrophages, contributes hepatocellular stellate part complex interplay types.60,72,73 markers consistent finding pathogenesis humans uncertain.74Key Fundamental elements imbalance nutrient delivery utilization coupled dysfunction. Interindividual differences dietary, behavioral, course. Systemic particularly stemming dysfunctional progression. Insulin promotes COMORBID CONDITIONS ASSOCIATED WITH closely precedes abnormalities hypertension).47,61,75–77 Having several confers histological mortality.8,47,78–81 association comorbidities reflect bidirectional interactions endocrine organs pancreas, muscle) through secretion hepatokines regulate metabolism, action, glucose metabolism,82–88 adipokines, myokines.39,89,90 Obesity progression.91–93 Body distribution contributory (Table 1). Android distribution, truncal subcutaneous visceral irrespective mass index (BMI).94–99 contrast, gynoid predominantly hips buttocks, appears protective NAFLD.39,100 Visceral fat, metabolically active mediates majority risk.101–105 becomes stressed, dysfunctional, inflamed, signaling progressively impaired, promoting inappropriate inflammation.47,106,107 TABLE 1 - Initial evaluation patient History Weight history; medical comorbidities; current medications; family T2DM, cirrhosis; OSA; use, amount, pattern duration Physical examination android gynoid, lipodystrophic), dorsal-cervical pad, acanthosis nigricans), firm splenomegaly, prominent abdominal veins, ascites, gynecomastia, spider angiomata, palmar erythema) Laboratory Hepatic panel, CBC platelets, plasma glycated hemoglobin (A1c), creatinine urine microalbumin ratio, hepatitis C if previously screened. Consider appropriate steatosis/steatohepatitis (). elevated chemistries present: autoimmune serologies, transferrin saturation, ceruloplasmin, alpha-1 antitrypsin genotype, CBC, complete blood count; OSA, obstructive sleep apnea; mellitus. Type mellitus (T2DM) T2DM impactful factor HCC.108–111 pathogenic both surprising (ranging 30% 75%)10,112,113 developing fibrosis.93,114–117 T2DM. there length biases, underscore strong relationship NAFLD. epidemiological studies. Early course, sensitivity,47 overt diabetes. 5-fold incident diabetes,75,118–121 therefore, screened progresses, so does failure, making manage.107 glycemic control NAFLD/NASH controversial, small showing poor fibrosis,68,122 whereas corroborated finding.116,117,123 described diabetes, much lower coexistent BMI).124,125 Hypertension commonly hypertension across spectrum, 6.5 early 14.5 cirrhosis.35 clearly additive respect NASH126,127 progression.30 Whether mechanistically inverse, manifestations drivers, established.128,129 Dyslipidemia twice likely exhibit NAFLD,120 serum subfractions atherogenic NAFLD.130,131 resolution improved HDL levels favorably lipoprotein subfractions, although unclear what extent mechanism intervention.132–134 progress they continue coronary artery disease135 despite normalization lipids lipoproteins due synthetic failure.130,136 Management dyslipidemia use moderate-intensity high-intensity statins first-line therapy based atherosclerotic scores. Combination hypolipemic agents, ezetimibe, PCSK-9 inhibitors, inclisiran, bempedoic fibrates, omega 3 icosapent ethyl, monotherapy statin achieve goals. Statins safe demonstrable mortality.137–140 However, practice, underused extensive data demonstrating safety, cirrhosis.141–144 future risk, confirmatory needed.138 safely decompensated statin-induced population,144 caution warranted. transplantation, careful monitoring.136 severely triglycerides >500 mg/dL), combination fibrates prescription grade omega-3 pancreatitis. Fibrates concentrations ≥200 mg/dL HDL-C <40 mg/dL. high-risk individuals, ethyl indicated adjunct risk. Pioglitazone optimization concomitant benefits profile. Caution taken myopathy. Obstructive apnea (OSA) OSA NAFLD,145 suggest histology.146–151 Intermittent hypoxia, critical consequence mitochondrial dysfunction,145 dysregulation metabolism,152,153 worse resistance,154–156 DNL.157 overweight obese polysomnography NAFLD158; independently drives unclear. exists heart arrhythmias, atrial fibrillation.159–167 Perturbed endothelial function, higher-risk nature lesions, impaired ischemic compensatory support link CVD.130,168–170 prospectively observational cohort, cardiac same stages; number relatively low.35 Optimizing goal reducing improving NAFLD.36,171,172 Aggressively treating conditions hypertension, hyperglycemia smoking cessation recommended decrease risk.173 Chronic kidney (CKD) cross-sectional (n=28,000 individuals) 2-fold CKD.174 overall, specifically, microvascular diabetic complications, especially CKD.175,176 Recently published CRN CKD stages.35 determined.Guidance statements: 1. 2. Limited exist safety efficacy could 3. Hypertriglyceridemia managed supplementation fibrates. 4. 5. Prevalence Death thus, adherence age-appropriate survival. INITIAL EVALUATION OF PATIENT incidentally noted imaging chemistries. It note normal values laboratories true alanine aminotransferase (ALT) 29 33 U/L men 19 25 women.177 comorbidities, assessment intake, exclusion physical profile atypical comorbidities) additional/alternate etiologies, less excluded 2). fibrosing isolation explain exaggerated specific contexts 2).178 Several exacerbate during 3). gene-based currently familial aggregation supports gene-environment fibrosis.209,210 consider testing Condition scenario Diagnostic test Treatment Hypobetalipoproteinemia Low LDL, triglycerides, malabsorption ApoB level, (MTTP, PCSK-9) Low-fat diet, fat-soluble vitamin LAL deficiency Markedly LDL-C HDL-C, xanthelasma, hypersplenism, young age, predominately microvesicular Enzyme assay, replacement Nutrient carnitine, choline) Anorexia, short bowel, bypass surgeries Supplementation Wilson Younger neuropsychiatric symptoms, alkaline phosphatase, ceruloplasmin 24-h copper; quantitative copper Chelation Celiac Iron deficiency, pain, bloating, D bone loss, diarrhea, dermatitis herpetiformis Tissue transglutaminase IgA, duodenal Gluten-free diet ApoB, apolipoprotein B; high-density cholesterol; immunoglobulin A; LAL, lysosomal lipase; LDL-C, LDL cholesterol. Drugs mechanistic links Drug Mechanism Histological References Amiodarone Promotion DNL, impairment β-oxidation steatohepatitis, phospholipidosis, 179–184 5-FU Accumulation catabolites capacity metabolize 185–188 Irinotecan Induces dysfunction, autophagy Steatohepatitis 189–194 Tamoxifen Estrogen modulator, promotion β-oxidation. *May Steatosis 195–203 Methotrexate Mitochondrial (inhibits electron transport chain), canals Hering Steatosis, 204–206 Corticosteroids Exacerbation

Language: Английский

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Metabolic-associated fatty liver disease and lipoprotein metabolism

Molecular Metabolism, Journal Year: 2021, Volume and Issue: 50, P. 101238 - 101238

Published: April 20, 2021

Non-alcoholic fatty liver disease, or as recently proposed 'metabolic-associated disease' (MAFLD), is characterized by pathological accumulation of triglycerides and other lipids in hepatocytes. This common disease can progress from simple steatosis to steatohepatitis, eventually end-stage diseases. MAFLD closely related disturbances systemic energy metabolism, including insulin resistance atherogenic dyslipidemia. The the central organ lipid metabolism secreting very low density lipoproteins (VLDL) and, on hand, internalizing acids lipoproteins. review article discusses recent research addressing hepatic synthesis, VLDL production, lipoprotein internalization well exchange between adipose tissue context MAFLD. Liver triggered excessive triglyceride synthesis utilizing derived white (WAT), de novo lipogenesis (DNL) endocytosed remnants triglyceride-rich In consequence high content, secretion enhanced, which primary cause complex dyslipidemia typical for subjects with Interventions reducing secretory capacity attenuate while they exacerbate MAFLD, indicating that balance storage versus hepatocytes a critical parameter determining outcome. Proof concept studies have shown promoting combustion tissues reduces load thus ameliorates Moreover, hepatocellular DNL WAT-derived be targeted treat However, more needed understand how individual transporters, enzymes, their isoforms affect vivo, whether these two aspects selectively treated. Processing cholesterol-enriched appears less important steatosis. It may, however, modulate inflammation consequently progression.

Language: Английский

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Immune cell-mediated features of non-alcoholic steatohepatitis

Nature reviews. Immunology, Journal Year: 2021, Volume and Issue: 22(7), P. 429 - 443

Published: Nov. 5, 2021

Non-alcoholic fatty liver disease (NAFLD) includes a range of hepatic manifestations, starting with steatosis and potentially evolving towards non-alcoholic steatohepatitis (NASH), cirrhosis or even hepatocellular carcinoma. NAFLD is major health burden, its incidence increasing worldwide. Although it primarily disturbed metabolism, involves several immune cell-mediated inflammatory processes, particularly when reaching the stage NASH, at which point inflammation becomes integral to progression disease. The cell landscape diverse steady state further evolves during NASH direct consequences for severity. In this Review, we discuss current concepts related role cells in onset NASH. A better understanding mechanisms by contribute pathogenesis should aid design innovative drugs target therapeutic options are limited. (NASH) serious chronic disorder prevalence Metabolic nature, also mobilizes system. Here, Huby Gautier knowledge regarding how subsets affect progression.

Language: Английский

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Emerging therapeutic approaches for the treatment of NAFLD and type 2 diabetes mellitus

Nature Reviews Endocrinology, Journal Year: 2021, Volume and Issue: 17(8), P. 484 - 495

Published: June 15, 2021

Language: Английский

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Hepatic inflammatory responses in liver fibrosis

Nature Reviews Gastroenterology & Hepatology, Journal Year: 2023, Volume and Issue: 20(10), P. 633 - 646

Published: July 3, 2023

Language: Английский

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The Power of Plasticity—Metabolic Regulation of Hepatic Stellate Cells

Cell Metabolism, Journal Year: 2020, Volume and Issue: 33(2), P. 242 - 257

Published: Nov. 23, 2020

Language: Английский

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Nonalcoholic fatty liver disease (NAFLD) from pathogenesis to treatment concepts in humans

Molecular Metabolism, Journal Year: 2020, Volume and Issue: 50, P. 101122 - 101122

Published: Nov. 20, 2020

Nonalcoholic fatty liver disease (NAFLD) comprises hepatic alterations with increased lipid accumulation (steatosis) without or inflammation (nonalcoholic steatohepatitis, NASH) and/or fibrosis in the absence of other causes disease. NAFLD is developing as a burgeoning health challenge, mainly due to worldwide obesity and diabetes epidemics. This review summarizes knowledge on pathogenesis underlying by focusing studies humans hypercaloric nutrition, including effects saturated fat fructose, well adipose tissue dysfunction, leading lipotoxicity, abnormal mitochondrial function, oxidative stress, highlights intestinal dysbiosis. These mechanisms are discussed context current treatments targeting metabolic pathways results related clinical trials. Recent have provided evidence that certain conditions, for example, severe insulin-resistant (SIRD) subgroup (cluster) presence an increasing number gene variants, seem predispose excessive risk its accelerated progression. trials been frequently unsuccessful halting preventing progression, perhaps partly unselected cohorts later stages NAFLD. On basis this literature review, study proposed screening individuals highest genetic acquired SIRD subgroup, treatment concepts earliest pathophysiolgical alterations, namely, adipocyte dysfunction insulin resistance.

Language: Английский

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The Role of Insulin Resistance and Diabetes in Nonalcoholic Fatty Liver Disease

International Journal of Molecular Sciences, Journal Year: 2020, Volume and Issue: 21(11), P. 3863 - 3863

Published: May 29, 2020

Nonalcoholic fatty liver disease (NAFLD) consists of the entire spectrum in patients without significant alcohol consumption, ranging from nonalcoholic (NAFL) to steatohepatitis (NASH) cirrhosis, with NASH recently shown as an important cause hepatocellular carcinoma (HCC). There is a close relationship between insulin resistance (IR) and NAFLD, five-fold higher prevalence NAFLD type 2 diabetes (T2DM) compared that T2DM. IR involved progression conditions such steatosis NASH, well hepatic fibrosis progression. The mechanisms underlying these processes involve genetic factors, fat accumulation, alterations energy metabolism, inflammatory signals derived various cell types including immune cells. In NASH-associated fibrosis, principal responsible for extracellular matrix production stellate (HSC). HSC activation by involves "direct" "indirect" pathways. This review will describe molecular inflammation IR, T2DM HCC NAFLD.

Language: Английский

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