Prospective validation of a noninvasive index for predicting liver fibrosis in hepatitis C virus-infected liver transplant recipients

A Comprehensive Review of Liver Allograft Fibrosis and Steatosis: From Cause to Diagnosis

Despite advances in posttransplant care, long-term outcomes for liver transplant recipients remain unchanged. Approximately 25% of recipients will advance to graft cirrhosis and require retransplantation. Graft fibrosis progresses in the context of de novo or recurrent disease. Recurrent hepatitis C virus infection was previously the most important cause of graft failure but is now curable in the majority of patients. However, with an increasing prevalence of obesity and diabetes and nonalcoholic fatty liver disease as the most rapidly increasing indication for liver transplantation, metabolic dysfunction-associated liver injury is anticipated to become an important cause of graft fibrosis alongside alloimmune hepatitis and alcoholic liver disease. To better understand the landscape of the graft fibrosis literature, we summarize the associated epidemiology, cause, potential mechanisms, diagnosis, and complications. We additionally highlight the need for better noninvasive methods to ameliorate the management of graft fibrosis. Some examples include leveraging the microbiome, genetic, and machine learning methods to address these limitations. Overall, graft fibrosis is routinely seen by transplant clinicians, but it requires a better understanding of its underlying biology and contributors that can help inform diagnostic and therapeutic practices.

Early periportal sinusoidal fibrosis is an accurate marker of accelerated HCV recurrence after liver transplantation

BACKGROUND & AIMS

Significant liver fibrosis (F ⩾ 2) and portal hypertension (hepatic venous pressure gradient [HVPG] ⩾ 6 mmHg) 1 year after liver transplantation (LT) are predictors of severe hepatitis C recurrence. Periportal sinusoidal fibrosis (SF) is an early expression of the fibrogenic process in response to liver injury. We aimed to evaluate whether SF in early liver biopsies represents an early and accurate marker for identifying patients with severe HCV recurrence after LT.

METHODS

A total of 101 HCV LT patients with early biopsy (<6 months), and HVPG measurement and/or liver biopsy one year after LT were included. Early biopsies were stained with Sirius Red and SF was graded semi-quantitatively. Results were compared between groups (significant SF vs. non-significant SF) and correlated with the development of severe HCV recurrence one year after LT.

RESULTS

Patients with early significant SF had older donor age and higher necroinflammatory activity (NIA). The presence of early significant SF enabled identification of 78.9% and 90.6% of patients with F ⩾ 2 and HVPG ⩾ 6 mmHg, respectively, one year after LT. Donor age and NIA were independent predictors of significant fibrosis (F ⩾ 2) one year after LT, whereas donor age, ALT (3 months), NIA, and SF grade were independent predictors of portal hypertension (HVPG ⩾ 6).

CONCLUSIONS

Significant SF in early biopsies is a good predictor of severe hepatitis C recurrence. This histological finding, when combined with simple variables, may be useful to select the best candidates for early antiviral therapy after LT.

[Serum markers of liver fibrosis in patients with chronic hepatitis C infection. Prognostic value of noninvasive markers of fibrosis in liver transplantation]

Liver fibrosis must be evaluated in patients with chronic hepatitis C, since its severity will affect prognosis and the indication of antiviral therapy. Combining serological markers of fibrosis in algorithms or scores can identify a substantial number of patients with significant fibrosis and most patients with liver cirrhosis, thus potentially avoiding a large number of biopsies. Although these algorithms should be interpreted with caution, due to their possible limitations, their high reproducibility, applicability and availability make them an essential tool in the current evaluation of patients with chronic hepatitis C infection. In contrast, serological markers have been found to be less effective in the diagnosis of fibrosis in the context of recurrent hepatitis C infection after liver transplantation. However, an algorithm for direct markers has shown excellent predictive ability in liver transplant recipients with hepatitis C. Consequently, this algorithm seems to be an excellent tool to establish prognosis and indicate antiviral therapy.

Progression of liver fibrosis in post-transplant hepatitis C: mechanisms, assessment and treatment

Liver fibrosis results from an excessive wound healing response in most chronic liver diseases, such as hepatitis C. Despite great advances in antiviral therapy in recent years, progressive liver fibrosis remains a major problem for patients with recurrent hepatitis C after liver transplantation. Liver biopsy remains a central tool in the management of HCV-positive liver transplant recipients, but reliable non-invasive methods for the assessment of liver fibrosis, such as ultrasound elastography, are increasingly being incorporated in the management of post-transplant patients, helping predict prognosis, guide treatment decisions, and stratify patients for emerging antifibrotic therapies. In this manuscript, we will review the natural history as well as tools to monitor fibrosis progression in the HCV-positive liver transplant recipient, the mechanisms underlying rapid fibrosis progression in up to 30% of these patients, the effect of antiviral therapies and highlight promising antifibrotic approaches.

Staging of liver disease: which option is right for my patient?

It is important to assess the stage of liver fibrosis in chronic hepatitis C to guide treatment decisions. Liver biopsy has limitations in staging fibrosis. Several blood tests, algorithms, and imaging tests have been studied as noninvasive markers to stage fibrosis in hepatitis C. In patients without suspicion for cirrhosis, 2 noninvasive methods can be used to predict presence of absence of significant liver fibrosis; however, liver biopsy remains the gold standard. It is imperative not to miss the diagnosis of cirrhosis, because this has further implications for screening of hepatocellular carcinoma and varices.

Biomarkers of disease differentiation: HCV recurrence versus acute cellular rejection

The wound-healing process induced by chronic hepatitis C virus (HCV) infection triggers liver damage characterized by fibrosis development and finally cirrhosis. Liver Transplantation (LT) is the optimal surgical treatment for HCV-cirrhotic patients at end-stage liver disease. However, acute cellular rejection (ACR) and HCV recurrence disease represent two devastating complications post-LT. The accurate differential diagnosis between both conditions is critical for treatment choice, and similar histological features represent a challenge for pathologists. Moreover, the HCV recurrence disease severity is highly variable post-LT. HCV recurrence disease progression is characterized by an accelerated fibrogenesis process, and almost 30% of those patients develop cirrhosis at 5-years of follow-up. Whole-genome gene expression (WGE) analyses through well-defined oligonucleotide microarray platforms represent a powerful tool for the molecular characterization of biological process. In the present manuscript, the utility of microarray technology is applied for the ACR and HCV-recurrence biological characterization in post-LT liver biopsy samples. Moreover, WGE analysis was performed to identify predictive biomarkers of HCV recurrence severity in formalin-fixed paraffin-embedded liver biopsies prospectively collected.

Spanish society of liver transplantation (SETH) consensus recommendations on hepatitis C virus and liver transplantation

In November 2010, the Spanish Society of Liver Transplantation (Sociedad Española de Trasplante Hepático, SETH) held a consensus conference. One of the topics of debate was liver transplantation in patients with hepatitis C. This document reviews (i) the natural history of post-transplant hepatitis C, (ii) factors associated with post-transplant prognosis in patients with hepatitis C, (iii) the role of immunosuppression in the evolution of recurrent hepatitis C and response to antiviral therapy, (iv) antiviral therapy, both before and after transplantation, (v) follow-up of patients with recurrent hepatitis C and (vi) the role of retransplantation.

Liver transplantation and hepatitis C

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompensation. The use of poor quality organs, particularly from older donors, has a highly negative impact on the severity of recurrence and patient/graft survival. Although immunosuppressive regimens have a considerable impact on the outcome, the optimal regimen after liver transplantation for HCV-infected patients remains unclear. Disease progression monitoring with protocol biopsy and new noninvasive methods is essential for predicting patient/graft outcome and starting antiviral treatment with the appropriate timing. Antiviral treatment with pegylated interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. Living-donor liver transplantation is now widely accepted as an established treatment for HCV cirrhosis and the results are equivalent to those of deceased donor liver transplantation.

Liver transplantation and hepatitis C

Hepatitis C virus (HCV)-related end-stage cirrhosis with/without hepatocellular carcinoma is the primary indication for liver transplantation in many countries. Unfortunately, HCV is not eliminated by transplantation and graft re-infection is the rule, resulting in HCV-related graft disease. The natural history of recurrent hepatitis is variable; overall, progression to cirrhosis occurs in 20-30% and allograft failure in 10% after 5-10 years from transplantation. The use of poor quality organs, particularly from old donors, has a significant negative impact on disease severity and transplant outcome. In contrast, antiviral therapy, particularly if it results in permanent eradication of the virus, is associated with improved histology, reduced rate of graft decompensation and enhanced outcome. Disease monitoring, through protocol liver biopsies and new non-invasive tools, is essential to select patients at need of antiviral therapy. Peginterferon with ribavirin, used similarly to what is done in the non-transplant setting, is currently the treatment of choice; sustained viral response is achieved in about 35% of cases. Side effects, particularly anemia, are extremely frequent and sometimes severe (rejection, de novo autoimmune hepatitis). Retransplantation (RT) is the last option for the small subset of patients with allograft failure due to HCV recurrence who fulfil minimum criteria based on RT survival models.

New and Evolving Management Paradigms for Hepatitis C after Liver Transplantation

Hepatitis-C induced liver failure is the leading indication for liver transplantation in the United States, and the burden of hepatitis C virus (HCV)-induced liver disease is not expected to peak for at least another decade. 2011 will usher in a new era of directly acting antiviral therapies and personalized medicine that will assist patients and clinicians in choosing the best drug regimen. Specific markers to predict sustained virologic response (SVR) in the posttransplant setting are under development, and the role of graft genetic markers like interleukin-28B and interferon-γ inducible protein-10 have yet to be fully defined. Lessons and experiences from treating the pretransplant population will be applied to patients with recurrent posttransplant HCV while studies specific to this population proceed. New paradigms for HCV treatment give promise to reducing the pretransplant burden of disease and improving SVR rates in the posttransplant population.

Noninvasive tests for evaluation of fibrosis in HCV recurrence after liver transplantation: a systematic review

Noninvasive tests (NIT) for evaluation of hepatic fibrosis have not been evaluated extensively in liver transplantation. We systematically reviewed the literature regarding NIT after liver transplantation. We identified 14 studies evaluating NIT based on serum markers and/or liver imaging techniques: 10 studies assessed NIT in recipients with recurrent HCV infection for fibrosis and four studies evaluated predictors of progression of fibrosis in recurrent HCV. Transient Elastography (TE) had good discrimination for significant fibrosis (median AUROC: 0.88). Among the serum NIT, APRI had good performance (median AUROC: 0.75). TE performed better than serum (direct and indirect) NIT for significant fibrosis with median AUROC 0.88 (vs. 0.66, P < 0.001), median sensitivity 0.86 (vs. 0.56, P = 0.002), median NPV 0.90 (vs. 0.74, P = 0.05) and median PPV 0.80 (vs. 0.63, P = 0.02). TE compared to indirect serum NIT, had better performance, but was not superior to APRI score. Finally, direct, compared to indirect NIT, were not significantly different except for specificity: median: 0.83 vs. 0.69, respectively, P = 0.04. In conclusion, NIT could become an important tool in clinical management of liver transplant recipients, but whether they can improve clinical practice needs further evidence. Their optimal combination with liver biopsy and assessment of collagen content requires investigation.

Hepatitis C virus recurrence after liver transplantation: biomarkers of disease and fibrosis progression

End-stage liver disease due to hepatitis C virus infection (HCV) is the principal indication for liver transplantation. In the USA, over a third of available liver allografts are transplanted into recipients with chronic HCV infection. Reinfection of the graft is universal, but the impact of reinfection on short- and long-term liver function is highly variable. HCV infection in liver transplantation recipients is characterized by an accelerated fibrogenesis, with approximately a third of patients developing cirrhosis within 5 years of follow-up. HCV is associated with decreased patient and graft survival when compared with other indications of orthotopic liver transplantation. The mechanisms responsible for the accelerated liver damage in HCV-infected orthotopic liver transplantation recipients remain largely unknown.