Utility and appropriateness of the fatty liver inhibition of progression (FLIP) algorithm and steatosis, activity, and fibrosis (SAF) score in the evaluation of biopsies of nonalcoholic fatty liver disease

Continuous Grading of Early Fibrosis in NAFLD Using Label-Free Imaging: A Proof-of-Concept Study

Background and Aims

Early detection of fibrosis is important in identifying individuals at risk for advanced liver disease in non-alcoholic fatty liver disease (NAFLD). We tested whether second-harmonic generation (SHG) and coherent anti-Stokes Raman scattering (CARS) microscopy, detecting fibrillar collagen and fat in a label-free manner, might allow automated and sensitive quantification of early fibrosis in NAFLD.

Methods

We analyzed 32 surgical biopsies from patients covering histological fibrosis stages 0–4, using multimodal label-free microscopy. Native samples were visualized by SHG and CARS imaging for detecting fibrillar collagen and fat. Furthermore, we developed a method for quantitative assessment of early fibrosis using automated analysis of SHG signals.

Results

We found that the SHG mean signal intensity correlated well with fibrosis stage and the mean CARS signal intensity with liver fat. Little overlap in SHG signal intensities between fibrosis stages 0 and 1 was observed. A specific fibrillar SHG signal was detected in the liver parenchyma outside portal areas in all samples histologically classified as having no fibrosis. This signal correlated with immunohistochemical location of fibrillar collagens I and III.

Conclusions

This study demonstrates that label-free SHG imaging detects fibrillar collagen deposition in NAFLD more sensitively than routine histological staging and enables observer-independent quantification of early fibrosis in NAFLD with continuous grading.

Nonalcoholic Fatty Liver Disease: Pros and Cons of Histologic Systems of Evaluation

The diagnostic phenotype of nonalcoholic fatty liver disease (NAFLD)--in particular, the most significant form in terms of prognosis, nonalcoholic steatohepatitis (NASH)--continues to rely on liver tissue evaluation, in spite of remarkable advances in non-invasive algorithms developed from serum-based tests and imaging-based or sonographically-based tests for fibrosis or liver stiffness. The most common tissue evaluation remains percutaneous liver biopsy; considerations given to the needle size and the location of the biopsy have the potential to yield the most representative tissue for evaluation. The pathologist's efforts are directed to not only global diagnosis, but also assessment of severity of injury. Just as in other forms of chronic liver disease, these assessments can be divided into necroinflammatory activity, and fibrosis with parenchymal remodeling, in order to separately analyze potentially reversible (grade) and non-reversible (stage) lesions. These concepts formed the bases for current methods of evaluating the lesions that collectively comprise the phenotypic spectra of NAFLD. Four extant methods have specific applications; there are pros and cons to each, and this forms the basis of the review.

Liver fibrosis in non-alcoholic fatty liver disease - diagnostic challenge with prognostic significance

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the Western world, with a prevalence of 20%. In a subgroup of patients, inflammation, ballooning degeneration of hepatocytes and a varying degree of fibrosis may develop, a condition named non-alcoholic steatohepatitis. Advanced liver fibrosis (stage F3) and cirrhosis (stage F4) are histologic features that most accurately predict increased mortality in both liver-related and cardiovascular diseases. Patients with advanced fibrosis or cirrhosis are at risk for complications such as hepatocellular carcinoma and esophageal varices and should therefore be included in surveillance programs. However, liver disease and fibrosis are often unrecognized in patients with NAFLD, possibly leading to a delayed diagnosis of complications. The early diagnosis of advanced fibrosis in NAFLD is therefore crucial, and it can be accomplished using serum biomarkers (e.g., the NAFLD Fibrosis Score, Fib-4 Index or BARD) or non-invasive imaging techniques (transient elastography or acoustic radiation force impulse imaging). The screening of risk groups, such as patients with obesity and/or type 2 diabetes mellitus, for NAFLD development with these non-invasive methods may detect advanced fibrosis at an early stage. Additionally, patients with a low risk for advanced fibrosis can be identified, and the need for liver biopsies can be minimized. This review focuses on the diagnostic challenge and prognostic impact of advanced liver fibrosis in NAFLD.

Validation of AshTest as a Non-Invasive Alternative to Transjugular Liver Biopsy in Patients with Suspected Severe Acute Alcoholic Hepatitis

BACKGROUND/AIMS

According to guidelines, the histological diagnosis of severe alcoholic steatohepatitis (ASH) can require liver biopsy if a specific treatment is needed. The blood test AshTest (BioPredictive, Paris, France) has been initially validated for the non-invasive diagnosis of ASH in a large population of heavy drinkers. The aim was to validate the AshTest accuracy in the specific context of use of patients with suspected severe ASH, in order to reduce the need for transjugular biopsy before deciding treatment.

METHODS

The reference was liver biopsy, performed using the transjugular route, classified according to its histological severity as none, minimal, moderate or severe. Biopsies were assessed by the same experienced pathologist, blinded to simultaneous AshTest results.

RESULTS

A total of 123 patients with severe clinical ASH (recent jaundice and Maddrey function greater or equal to 32) were included, all had cirrhosis and 80% had EASL histological definition of ASH. 95% of patients received prednisolone; and the 2-year mortality was 63%. The high AshTest performance was confirmed both for the binary outcome [AUROC = 0.803 (95%CI 0.684-0.881)] significantly higher than the AST/ALT AUROC [0.603 (0.462-0.714); P<0.001], and for the severity of ASH-score system by the Obuchowski measures for [mean (SE) 0.902 (0.017) vs. AST/ALT 0.833 (0.023); P = 0.01], as well as for the diagnosis and severity of ballooning, PMN and Mallory bodies. According to attributability of discordances, AshTest had a 2-7% risk of 2 grades misclassification.

CONCLUSION

These results confirmed the diagnostic performance of AshTest in cirrhotic patients with severe clinical ASH, in the specific context of use of corticosteroid treatment. AshTest is an appropriate non-invasive alternative to transjugular liver biopsy.

Liver Fibrosis, but No Other Histologic Features, Is Associated With Long-term Outcomes of Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

Histologic analysis of liver biopsy specimens allows for grading and staging of nonalcoholic fatty liver disease (NAFLD). We performed a longitudinal study to investigate the long-term prognostic relevance of histologic features for patients with NAFLD.

METHODS

We performed a retrospective analysis of 619 patients diagnosed with NAFLD from 1975 through 2005 at medical centers in the United States, Europe, and Thailand. Patients underwent laboratory and biopsy analyses, and were examined every 3-12 months after their diagnosis. Outcomes analyzed were overall mortality, liver transplantation, and liver-related events. Cumulative outcomes were compared by log-rank analysis. Cox proportional-hazards regression was used to estimate adjusted hazard ratios (HRs). Time at risk was determined from the date of liver biopsy to the date of outcome or last follow-up examination.

RESULTS

Over a median follow-up period of 12.6 years (range, 0.3-35.1 y), 193 of the patients (33.2%) died or underwent liver transplantation. Features of liver biopsies significantly associated with death or liver transplantation included fibrosis stage 1 (HR, 1.88; 95% confidence interval [CI], 1.28-2.77), stage 2 (HR, 2.89; 95% CI, 1.93-4.33), stage 3 (HR, 3.76; 95% CI, 2.40-5.89), and stage 4 (HR, 10.9; 95% CI, 6.06-19.62) compared with stage 0, as well as age (HR, 1.07; 95% CI, 1.05-1.08), diabetes (HR, 1.61; 95% CI, 1.13-2.30), current smoking (HR, 2.62; 95% CI, 1.67-4.10), and statin use (HR, 0.32; 95% CI, 0.14-0.70). Twenty-six patients (4.2%) developed liver-related events; fibrosis stage 3 (HR, 14.2; 95% CI, 3.38-59.68) and stage 4 (HR, 51.5; 95% CI, 9.87-269.2) compared with stage 0, were associated significantly with the events. Patients with fibrosis, regardless of steatohepatitis or NAFLD activity score, had shorter survival times than patients without fibrosis.

CONCLUSIONS

In a longitudinal study of patients with NAFLD, fibrosis stage, but no other histologic features of steatohepatitis, were associated independently with long-term overall mortality, liver transplantation, and liver-related events.

Current efforts and trends in the treatment of NASH

Of all the aspects of non-alcoholic fatty liver disease (NAFLD), the slowest advances have occurred in the therapeutic field. Thirty-five years after its formal description and after 15 years of intense scrutiny from researchers worldwide, there is still no approved drug for the treatment of non-alcoholic steatohepatits (NASH). In the meantime, progress in the understanding of pathophysiology, diagnosis - both invasive and non-invasive, epidemiology and even natural history have been substantial or, at times, spectacular. In contrast, hepatitis C virus (HCV) therapy underwent constant improvement and even before the great acceleration of the past few years, patients were already being offered approved therapies that were increasingly more efficient. What then explains such a slow pace of therapeutic advances in NASH, and will this change in the near future? Here we will review commonly-held myths that have diverted attention from therapy of NASH, obstacles that have slowed down industrial development of drugs for this indication, and recent achievements that will create better conditions for drug development programs. We will also briefly review current knowledge of non-pharmacological and pharmacological management in this early era of NASH therapies.

A clinical perspective of the link between metabolic syndrome and hepatocellular carcinoma

Metabolic syndrome (MS), which is defined as a constellation of clinico-biological features closely related to insulin-resistance has reached epidemic levels in Western Europe and Northern America. Non-alcoholic fatty liver disease (NAFLD) represents the hepatic manifestation of MS. As its incidence parallels that of MS, NAFLD is currently becoming one of the most frequent chronic liver diseases in Western countries. On one hand, MS favors the development of hepatocellular carcinoma (HCC) either through NAFLD liver parenchymal alterations (steatosis; steatohepatitis; fibrosis), or in the absence of significant underlying liver parenchyma changes. In this setting, HCC are often diagnosed incidentally, tend to be larger than in patients developing HCC on cirrhosis and therefore frequently require major liver resections. On the other hand, MS patients are at increased risk of both liver-related postoperative complications and increased cardiorespiratory events leading to non-negligible mortality rates following liver surgery. These deleterious effects seem to be related to the existence of impaired liver function even in the absence of severe fibrosis but also higher cardiorespiratory sensitivity in a setting of MS/NAFLD. Hence, specific medical and surgical improvements in the perioperative management of these patients are required. These include complete preoperative cardiorespiratory work-up and the wide use of preoperative liver volume modulation. Finally, the long-term prognosis after curative surgery for MS-related HCC does not seem to be worse than for other HCC occurring on classical chronic liver diseases. This is probably related to less aggressive tumor behavior with lower micro vascular invasion and decreased rates of poorly differentiated lesions. In this setting, several medical therapies including metformin could be of value in the prevention of both occurrence and recurrence of HCC.

Synthesis and application of strawberry-like Fe3O4-Au nanoparticles as CT-MR dual-modality contrast agents in accurate detection of the progressive liver disease

Development of non-invasive assay for the accurate diagnosis of progressive liver diseases (e.g., fatty liver and hepatocellular carcinoma (HCC)) is of great clinical significance and remains to be a big challenge. Herein, we reported the synthesis of strawberry-like Fe3O4-Au hybrid nanoparticles at room temperature that simultaneously exhibited fluorescence, enhanced X-ray attenuation, and magnetic properties. The results of in vitro fluorescence assay showed that the nanoparticles had significant photo-stability and could avoid the endosome degradation in cells. The in vivo imaging of normal mice demonstrated that the Fe3O4-Au nanoparticles provided 34.61-fold contrast enhancement under magnetic resonance (MR) guidance 15 min post the administration. Computed tomography (CT) measurements showed that the highest Hounsfield Unit (HU) was 174 at 30 min post the injection of Fe3O4-Au nanoparticles. In vivo performance of the Fe3O4-Au nanoparticles was further evaluated in rat models bearing three different liver diseases. For the fatty liver model, nearly homogeneous contrast enhancement was observed under both MR (highest contrast ratio 47.33) and CT (from 19 HU to 72 HU) guidances without the occurrences of focal nodules or dysfunction. For the cirrhotic liver and HCC, pronounced enhancement under MR and CT guidance could be seen in liver parenchyma with highlighted lesions after Fe3O4-Au injection. Furthermore, pathological, hematological and biochemical analysis revealed the absence of acute and chronic toxicity, confirming the biocompatibility of our platform for in vivo applications. Collectively, These Fe3O4-Au nanoparticles showed great promise as a candidate for multi-modality bio-imaging.

Transitions of histopathologic criteria for diagnosis of nonalcoholic fatty liver disease during the last three decades

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome, and is the most common type of chronic liver diseases in the majority of developed countries. NAFLD shows a wide spectrum of disorders including simple steatosis, nonalcoholic steatohepatitis (NASH), and cirrhosis. While simple steatosis is recognized to be benign and stable, NASH is considered to be an aggressive form of the disease progressing to cirrhosis. Currently, differentiation between NASH and simple steatosis can be done only by liver biopsy. Despite many proposals and revisions, the histological criteria for the differentiation have not been perfected yet. In this review article, the changes in the histopathologic criteria of NAFLD during the last three decades are summarized, and perspectives of the future changes are demonstrated. The discussion focuses on how pathologists have been dealing with “hepatocellular ballooning”. Loose criteria, in which hepatocellular ballooning was not required for the diagnosis of NASH, were applied in many clinical studies published in around 2000’s, whereas a strict criterion based on the presence/absence of hepatocellular ballooning was approved recently. Hence, simple and reliable methods of identifying ballooned hepatocytes are being sought. Clinical and pathological predictors of NAFLD-related hepatocarcinogenesis will also be sought in the future.

Prognostic value of liver fibrosis and steatosis biomarkers in type-2 diabetes and dyslipidaemia

BACKGROUND

In cardiometabolic disorders, non-alcoholic fatty liver disease is frequent and presumably associated with increased mortality and cardiovascular risk.

AIM

To evaluate the prognostic value of non-invasive biomarkers of liver fibrosis (FibroTest) and steatosis (SteatoTest) in patients with type-2 diabetes and/or dyslipidaemia.

METHODS

A total of 2312 patients with type-2 diabetes and/or dyslipidaemia were included and prospectively followed up for 5-15 years. The cardiovascular Framingham-risk score was calculated; advanced fibrosis and severe steatosis, were defined by FibroTest >0.48 and SteatoTest >0.69, respectively, as previously established.

RESULTS

During a median follow-up of 12 years, 172 patients (7.4%) died. The leading causes of mortality were cancer (31%) and cardiovascular-related death (20%). The presence of advanced fibrosis [HR (95% CI)] [2.98 (95% CI 1.78-4.99); P < 0.0001] or severe steatosis [1.86 (1.34-2.58); P = 0.0002] was associated with an increased risk of mortality. In a multivariate Cox model adjusted for confounders: the presence of advanced fibrosis was associated with overall mortality [1.95 (1.12-3.41); P = 0.02]; advanced fibrosis at baseline [n = 50/677; 1.92 (1.04-3.55); P = 0.04] and progression to advanced fibrosis during follow-up [n = 16/127; 4.8 (1.5-14.9); P = 0.007] were predictors of cardiovascular events in patients with type-2 diabetes. In patients with a Framingham-risk score ≥20%, the presence of advanced fibrosis was predictive of cardiovascular events [2.24 (1.16-4.33); P < 0.05].

CONCLUSIONS

Liver biomarkers, such as FibroTest and SteatoTest, have prognostic values in patients with metabolic disorders. FibroTest has prognostic value for predicting overall survival in patients with type-2 diabetes and/or dyslipidaemia. In type-2 diabetes, FibroTest predicted cardiovascular events and improved the Framingham-risk score.

Pathological features of fatty liver disease

Alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are significant causes of chronic liver disease worldwide. Both are characterized by histological lesions that can include steatosis, and each can lead to cirrhosis. It might be possible for pathologists to identify lesions and patterns of ALD and NAFLD; we review these lesions and propose methods to distinguish between the disorders. Any form of ALD can lead to end-stage liver disease, according to long-term studies of biopsy specimens and patient outcomes. Although steatosis can be a significant cofactor in progression of established chronic liver disease, or even development of hepatocellular carcinoma, only steatohepatitis indicates the presence of progressive liver disease in patients with NAFLD. Pediatric and adolescent NAFLD differ from adult nonalcoholic steatohepatitis and should be recognized as distinct conditions. Benign and malignant liver tumors have been more frequently reported with the increasing prevalence of obesity and diabetes. Histological scoring systems for ALD and NAFLD have been proposed to monitor efficacy in clinical trials and serve as prognostic factors. We review what we have learned from pathological analyses about the development of these disorders and how this information might be used to detect and treat them.

TM6SF2 rs58542926 influences hepatic fibrosis progression in patients with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an increasingly common condition, strongly associated with the metabolic syndrome, that can lead to progressive hepatic fibrosis, cirrhosis and hepatic failure. Subtle inter-patient genetic variation and environmental factors combine to determine variation in disease progression. A common non-synonymous polymorphism in TM6SF2 (rs58542926 c.449 C>T, p.Glu167Lys) was recently associated with increased hepatic triglyceride content, but whether this variant promotes clinically relevant hepatic fibrosis is unknown. Here we confirm that TM6SF2 minor allele carriage is associated with NAFLD and is causally related to a previously reported chromosome 19 GWAS signal that was ascribed to the gene NCAN. Furthermore, using two histologically characterized cohorts encompassing steatosis, steatohepatitis, fibrosis and cirrhosis (combined n=1,074), we demonstrate a new association, independent of potential confounding factors (age, BMI, type 2 diabetes mellitus and PNPLA3 rs738409 genotype), with advanced hepatic fibrosis/cirrhosis. These findings establish new and important clinical relevance to TM6SF2 in NAFLD.

Non-alcoholic fatty liver disease (NAFLD) is characterized by increased hepatic triglyceride content (HTGC) in the absence of high alcohol consumption. Here the authors show that a genetic variant in TM6SF2, which is known to be associated with HTGC, is a clinically relevant modifier of hepatic fibrogenesis and increases the risk of progressive NAFLD.