The Role of Radiologic Modalities in Diagnosing Nonalcoholic Steatohepatitis (NASH) and Fibrosis

Magnetic Resonance Spectroscopy of Hepatic Fat from Fundamental to Clinical Applications

The number of individuals suffering from fatty liver is increasing worldwide, leading to interest in the noninvasive study of liver fat. Magnetic resonance spectroscopy (MRS) is a powerful tool that allows direct quantification of metabolites in tissue or areas of interest. MRS has been applied in both research and clinical studies to assess liver fat noninvasively in vivo. MRS has also demonstrated excellent performance in liver fat assessment with high sensitivity and specificity compared to biopsy and other imaging modalities. Because of these qualities, MRS has been generally accepted as the reference standard for the noninvasive measurement of liver steatosis. MRS is an evolving technique with high potential as a diagnostic tool in the clinical setting. This review aims to provide a brief overview of the MRS principle for liver fat assessment and its application, and to summarize the current state of MRS study in comparison to other techniques.

The Use of Transient Elastography Technology in the Bariatric Patient: a Review of the Literature

Transient elastography (TE) is a non-invasive technology that demonstrates promise in assessing liver steatosis and fibrosis without the risks of traditional percutaneous liver biopsy. Many studies have examined its reliability in respect to liver biopsy, but fewer have examined using TE in obese and bariatric surgery patients. With evidence showing that bariatric surgery can lead to improvement of liver steatosis and fibrosis, TE has the potential to provide a simple avenue of hepatic assessment in patients before and after procedures. This review article investigates what is known about the reliability of TE and its implementation in obese and bariatric surgery patients.

Advances in the clinical use of collagen as biomarker of liver fibrosis

INTRODUCTION

Hepatic fibrosis is the excessive synthesis and deposition of extracellular matrix including collagen in the tissue. Chronic liver insult leads to progressive parenchymal damage, portal hypertension, and cirrhosis. Determination of hepatic collagen by invasive liver biopsy is the gold standard to estimate severity and stage of fibrosis. However, this procedure is associated with pain, carries the risk of infection and bleeding, and is afflicted with a high degree of sampling error. Therefore, there is urgent need for serological collagen-derived markers to assess collagen synthesis/turnover.

AREAS COVERED

Biochemical properties of collagens, cellular sources of hepatic collagen synthesis, and regulatory aspects in collagen expression. Markers are discussed suitable to estimate hepatic collagen synthesis and/or turnover. Discussed studies were identified through a PubMed search done in May 2020 and the authors' topic knowledge.

EXPERT OPINION

Hepatic fibrosis is mainly characterized by accumulation of collagen-rich scar tissue. Although traditionally performed liver biopsy is still standard in estimating hepatic fibrosis, there is evidence that noninvasive diagnostic scores and collagen-derived neo-epitopes provide clinical useful information. These noninvasive tests are less expensive than liver biopsy, better tolerated, safer, and more acceptable to patients. Therefore, these tests will lead to dramatic changes in diagnosis.

Association between steatohepatitis biomarkers and hepatocellular carcinoma after hepatitis C elimination

BACKGROUND

A strong association between chronic hepatitis C (CHC) and hepatic steatosis has been reported. However, the influence of steatohepatitis on hepatocellular carcinoma (HCC) after hepatitis C virus (HCV) elimination remains unclear.

AIM

To evaluate the development of HCC after HCV cure using a new steatohepatitis-related biomarker.

METHODS

This cohort study analysed the prospective database of 290 CHC patients without a history of HCC who achieved HCV elimination by direct-acting antivirals. We calculated the FibroScan-aspartate aminotransferase (FAST) score 12 weeks after the end of treatment (pw12). The risk of HCC was analysed using the multivariable Cox proportional hazard model.

RESULTS

HCV genotype (GT)1 was most prevalent at 72.4%, followed by GT2 (26.6%). Median follow-up period was 4.2 years (IQR 3.1-4.5). The cumulative HCC incidence for a FAST score ≥ 0.35 was significantly higher than that for a FAST score < 0.35 (log-rank test: P < 0.001). The annual HCC incidence rate for a FAST score ≥ 0.35 was significantly higher than that for a FAST score < 0.35, in patients with liver stiffness measurement (LSM) ≥10 kPa (adjusted hazard ratio [HR] 4.41, 95% confidence interval [CI] 1.30-15.0, P = 0.018). After adjusting for variables, including age, albumin, alpha-fetoprotein, the patatin-like phospholipase domain-containing the 3 (PNPLA3) rs738409 genotype, and pw12 fibrosis markers with FIB-4, non-alcoholic fatty liver disease fibrosis score, and LSM, FAST score ≥ 0.35 was associated with the development of HCC (adjusted HR 4.42, 95% CI 1.02-19.9, P = 0.043).

CONCLUSIONS

Steatohepatitis-related biomarkers with the FAST score are helpful for predicting the development of HCC after HCV elimination.

Baseline risk factors determine lack of biochemical response after SVR in chronic hepatitis C patients treated with DAAs

BACKGROUND AND AIMS

Liver function tests (alanine aminotransferase, ALT; gamma-glutamyltransferase, GGT) not always normalize after elimination of hepatitis C virus (HCV) by direct acting antivirals (DAAs), possibly indicating concomitant non-viral liver diseases. We analysed factors determining the biochemical response (normalized ALT/GGT) of DAA therapy in a large real-world cohort.

METHOD

The German Hepatitis C-Registry is a national multicenter registry study. Normal ALT was defined ≤35 U/L (female) and ≤50 U/L (male) or, according to AASLD, ≤19 U/L (female) and ≤30 U/L (male), normal GGT ≤40 U/L (female) and ≤60 U/L (male).

RESULTS

At baseline, ALT was elevated in 3705/4946 (74.9%), ALT (AASLD) in 4669/4946 (94.4%) and GGT in 3018/4906 (61.5%). In this study, 97% of patients achieved SVR12. At week 12 after end of therapy, ALT was elevated in 451/4946 (9.1%), ALT according to AASLD in 1906/4946 (38.5%) and GGT in 863/4879 (17.7%). Persistently elevated ALT after DAA therapy was independently associated with high body mass index (BMI), age <70 years, liver cirrhosis, diabetes, alcohol consumption and not achieving SVR12. Using the stricter AASLD criteria, opioid substitution and male sex were additional predictors. Higher GGT at week 12 was associated with high BMI, age >70 years, liver cirrhosis, diabetes, alcohol consumption, opioid substitution and non-SVR. Importantly, persistently elevated liver tests after treatment, particularly GGT, were associated with hepatic decompensation and mortality during 4-years follow-up.

CONCLUSION

Risk factors at baseline (obesity, diabetes, liver cirrhosis, alcohol consumption) are independently associated with persistently elevated liver function tests after SVR, indicating that these patients warrant further hepatological follow-up.

CLINICAL TRIAL REGISTRATION

German Clinical Trials Register (DRKS; ID DRKS00009717).

Current Status in Testing for Nonalcoholic Fatty Liver Disease (NAFLD) and Nonalcoholic Steatohepatitis (NASH)

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western countries with almost 25% affected adults worldwide. The growing public health burden is getting evident when considering that NAFLD-related liver transplantations are predicted to almost double within the next 20 years. Typically, hepatic alterations start with simple steatosis, which easily progresses to more advanced stages such as nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis. This course of disease finally leads to end-stage liver disease such as hepatocellular carcinoma, which is associated with increased morbidity and mortality. Although clinical trials show promising results, there is actually no pharmacological agent approved to treat NASH. Another important problem associated with NASH is that presently the liver biopsy is still the gold standard in diagnosis and for disease staging and grading. Because of its invasiveness, this technique is not well accepted by patients and the method is prone to sampling error. Therefore, an urgent need exists to find reliable, accurate and noninvasive biomarkers discriminating between different disease stages or to develop innovative imaging techniques to quantify steatosis.