Hepatic steatosis: a specific sign of hepatitis C reinfection after liver transplantation

Central portalization correlates with fibrosis but not with risk factors for nonalcoholic steatohepatitis in steatotic chronic hepatitis C

Concomitant steatosis in chronic hepatitis C is associated with fibrosis and unfavorable treatment outcome. Central zone injury in nonalcoholic steatohepatitis (NASH) manifests as central portalization, with centrizonal microvessels and ductular reaction. We investigated whether central portalization in steatotic HCV biopsies would identify patients with metabolic risk factors for NASH. Liver biopsies with chronic hepatitis C and >10% steatosis (n = 65) were evaluated for the degree of steatosis, zonation of steatosis, fibrosis, and nonalcoholic fatty liver disease (NAFLD) activity score. The presence of centrizonal microvessels, sinusoidal capillarization, ductular reaction, and CK7 positive intermediate-phenotype hepatocytes were evaluated by CD34 and CK7 immunostain. The degree of steatosis and fibrosis showed a positive correlation. Additional positive correlations were noted between centrizonal angiogenesis and NAFLD activity score and central portalization and fibrosis. However, neither central portalization nor zonation of steatosis identified patients with metabolic risk factors for NASH. Therefore, central portalization cannot be used as a surrogate marker to identify patients with metabolic risk factors for NASH in steatotic HCV biopsies. The mechanism of centrizonal injury in steatotic HCV hepatitis is not solely attributable to the metabolic risk factors for NASH.

Strategies to reduce hepatitis C virus recurrence after liver transplantation

Hepatitis C virus (HCV) is a major health problem that leads to chronic hepatitis, cirrhosis and hepatocellular carcinoma, being the most frequent indication for liver transplantation in several countries. Unfortunately, HCV re-infects the liver graft almost invariably following reperfusion, with an accelerated history of recurrence, leading to 10%-30% of patients progressing to cirrhosis within 5 years of transplantation. In this sense, some groups have even advocated for not re-transplanting this patients, as lower patient and graft outcomes have been reported. However, the management of HCV recurrence is being optimized and several strategies to reduce post-transplant recurrence could improve outcomes, decrease the rate of re-transplantation and optimize the use of available grafts. Three moments may be the focus of potential actions in order to decrease the impact of viral recurrence: the pre-transplant moment, the transplant environment and the post-transplant management. In the pre-transplant setting, it is not well established if reducing the pre transplant viral load affects the risk for HCV progression after transplant. Obviously, antiviral treatment can render the patient HCV RNA negative post transplant but the long-term benefit has not yet been fully established to justify the cost and clinical risk. In the transplant moment, factors as donor age, cold ischemia time, graft steatosis and ischemia/reperfusion injury may lead to a higher and more aggressive viral recurrence. After the transplant, discussion about immunosuppression and the moment to start the treatment (prophylactic, pre-emptive or once-confirmed) together with new antiviral drugs are of interest. This review aims to help clinicians have a global overview of post-transplant HCV recurrence and strategies to reduce its impact on our patients.

Hepatic steatosis is not always a contraindication for cadaveric liver transplantation

BACKGROUND

Macrovesicular steatosis is assumed to be an important risk factor for early allograft dysfunction (EAD) after orthotopic liver transplantation (OLT).

AIM

To evaluate the impact of steatosis in combination with other risk factors on the outcome of OLT.

METHODS

The degree of steatosis was analysed in 165 consecutive OLTs and was classified by histological examination as non (M0), mild (<30%, M1), moderate (30-60%, M2) or severe steatosis (>60%, M3). Recipients were analysed for EAD.

RESULTS

EAD was observed in 28% of patients with M0, 26% with M1, 53% with M2 and 73% with M3 (P < 0.001). Patients with EAD had a significantly shorter graft survival after liver transplantation (P = 0.005) but did not correlate with survival. In multivariate regression analysis, the grade of steatosis, donating after cardiocirculatory death (DCD) grafts and duration of cold ischaemia time were significantly associated with EAD (P < 0.001, P = 0.01 and P = 0.001, respectively).

CONCLUSION

Livers with severe (M3) steatosis from DCD donors, combined with a prolonged CIT have a high risk for developing EAD which is correlated with shorter graft survival. Therefore M3 livers should only be considered for OLT in selected recipients without the presence of additional risk factors.

Hepatitis C virus proteins induce lipogenesis and defective triglyceride secretion in transgenic mice

Chronic hepatitis C virus (HCV) infection is associated with altered lipid metabolism and hepatocellular steatosis. Virus-induced steatosis is a cytopathic effect of HCV replication. The goal of this study was to examine the mechanisms underlying HCV-induced lipid metabolic defects in a transgenic mouse model expressing the full HCV protein repertoire at levels corresponding to natural human infection. In this model, expression of the HCV full-length open reading frame was associated with hepatocellular steatosis and reduced plasma triglyceride levels. Triglyceride secretion was impaired, whereas lipogenesis was activated. Increased lipogenic enzyme transcription was observed, resulting from maturational activation and nuclear translocation of sterol regulatory element-binding protein 1c (SREBP1c). However, endoplasmic reticulum (ER) stress markers were expressed at similar levels in both HCV transgenic mice and their wild type counterparts, suggesting that SREBP1c proteolytic cleavage in the presence of HCV proteins was independent of ER stress. In conclusion, transgenic mice expressing the HCV full-length polyprotein at low levels have decreased plasma triglyceride levels and develop hepatocellular steatosis in the same way as HCV-infected patients. In these mice, SREBP1c activation by one or several HCV proteins induces de novo triglyceride synthesis via the lipogenic pathway, in a manner independent of ER stress, whereas triglyceride secretion is simultaneously reduced.

Donor livers with steatosis are safe to use in hepatitis C virus-positive recipients

Whether donor graft steatosis affects liver function and influences survival after liver transplantation is still open to debate. The aim of this study was to assess the impact of donor graft steatosis on long-term liver histology after liver transplantation. One hundred sixteen consecutive liver transplants were performed in 56 hepatitis C virus-positive (HCV+) patients and 60 HCV- patients who had protocol liver biopsies at 6, 12, 24, and 36 months after liver transplantation. Liver biopsies were obtained from all grafts. No steatosis was seen in 50.9% of the biopsies taken at the back table before implantation, whereas steatosis was mild in 39.6% of the samples and moderate/severe in 9.5% of the samples. In the 56 HCV+ recipients, fibrosis stage 3 was seen in 22.2% and stage 4 was seen in 2.2% of 45 biopsies at 36 months after liver transplantation. There was no correlation between donor graft steatosis and fibrosis after liver transplantation, regardless of the etiology of liver disease. No difference in 36-month survival after liver transplantation was seen, regardless of whether the etiology of the patient's liver disease was HCV-related or non-HCV-related (80.3% versus 75%; P = 0.4) and whether the steatosis in the graft was reportedly absent, mild, or moderate/severe (79.7% versus 73.9% versus 81.1%; P = 0.7). In conclusion, nearly one-quarter of HCV+ recipients have precirrhosis/cirrhosis 3 years after liver transplantation. Steatotic grafts do not seem to exacerbate the progression of fibrosis in HCV+ recipients, nor do they seem to negatively affect 3-year patient survival.

Lipid droplets and hepatitis C virus infection

Lipid droplets play an important part in the life cycle of hepatitis C virus and also are markers for steatosis, which is a common condition that arises during infection. These storage organelles are targeted by the viral core protein, which forms the capsid shell. Attachment of core to lipid droplets requires a C-terminal domain within the protein that is highly conserved between different virus isolates. In infected cells, the presence of core on lipid droplets creates loci that contain viral RNA and non-structural proteins involved in genome replication. Such locations may represent sites for initiating assembly and production of nascent virions. In addition to utilising lipid droplets as part the virus life cycle, hepatitis C virus induces their accumulation in infected hepatocytes. The mechanisms involved in this process are not understood but evidence from patient-based studies and model systems suggests the involvement of both viral and host factors.

Correlation between liver fibrosis and inflammation in patients transplanted for HCV liver disease

Hepatitis C virus (HCV) re-infection after liver transplantation (LT) is characterized by an accelerated disease progression in recent years with unclear mechanisms. We evaluate the relationship between progression of liver fibrosis and histological necro-inflammation in HCV recipients, according to age of transplant. Fifty-five patients transplanted (1993-2002) for HCV liver disease, were included in the study. Recipients were retrospectively stratified in three different age of transplant, of 40 months each: group 1) from January 1993 to May 1996; group 2) from June 1996 to august 1999; group 3) from September 1999 to December 2002. Grading (necro-inflammation) and staging (fibrosis) scores were evaluated in liver biopsies at 1, 2 and 3 years from LT (Ishak classification). For all age of transplant the main factor associated with fibrosis progression, was grading score (p < 0.05). However mean staging score for each point of grading increased from 0.3 +/- 0.2 in older LT to 0.7 +/- 0.5 in newer ones (p = 0.01). In conclusion in HCV-LT patients (1) liver fibrosis is strictly associated to histological necro-inflammation; (2) the proportion of this relationship has been changing in recent years since newer LT patients, show an increased amount of fibrosis in comparison with the older ones, for similar grading score.

[Treatment of recurrent hepatitis C virus infection after liver transplantation]

The main indication of liver transplantation is the final stage of liver cirrhosis developed in hepatitis C virus (HCV) infection. The recurrence of HCV infection after transplantation is a common situation. The recurrent hepatitis C is a progressive disease, in 20 percent of patients it produces liver cirrhosis without treatment beside immunosuppression within 5 years. The treatment of recurrent HCV infection is the most important factor of the survival in patients with transplantation. The authors review the factors influencing the progression of recurrent HCV infection on the basis of literary data and also on their observation. They discuss in details the effect of immunosuppressive treatment, the importance in the selection of corresponding immunosuppressive drugs. They review the main keypoints in the diagnosis of recurrent hepatitis C, underline the important role of liver biopsy carried out according to the protocol in the diagnosis, furthermore the hard consultation among pathologist, hepatologist and surgeon. They demonstrate the observations with the treatment of patients on the waiting list, the results in the early, preemptive treatment of recurrent chronic hepatitis, furthermore the treatment modalities and the results in patients with chronic hepatitis C histologically proved. The drug of choice of chronic hepatitis C after transplantation is the combined therapy with pegylated interferon and ribavirin. This therapy is able to assure virus-free stage in 20-50 percent of patients. In the virus-free patients the inflammatory activity in the liver significantly decreases, the histologic activity index improves. There are data showing the effect of treatment for inhibiting the fibrosis, but multicenter studies are necessary for the confirmation of these data. The advantage of early antiviral therapy without histologic alteration has not been confirmed by most of the trials. The anaemia and the neutropenia are frequent side effects in this patient group, that is why the applications of erythropoietin and granulocyte stimulating factor are recommended. Further trials and clinical studies are necessary for the optimal treatment of patients with recurrent hepatitis C, and to determine the dosage of pegylated interferon and ribavirin, to decrease the duration of therapy and the side effects, finally to achieve a healing phase of higher degree.

Management of hepatitis C infection after liver transplantation

Recurrent hepatitis C virus (HCV) infection after orthotopic liver transplantation (OLT) has been associated with progression to cirrhosis in approximately 20% of patients, 5 years postoperatively. Accelerated decompensation has also been noted when compared with cirrhosis in non-transplant patients. Different treatment strategies are available for recurrent HCV infection post-OLT, but efforts are hindered by the modest response rates, poor tolerability and the risk of rejection as well as graft loss. Anti-HCV immunoglobulin therapy to prevent graft infection with HCV has no established role at present but studies are ongoing. Treatment prior to transplantation in patients with decompensated cirrhosis has been evaluated but the results are too preliminary to make firm recommendations. Prophylactic interferon-based antiviral therapy in the early postoperative period to prevent graft infection was shown to have low response rates and high rates of adverse effects. Treatment of established recurrent HCV infection with combination peginterferon (pegylated interferon) and ribavirin is associated with 10-59% sustained virological response and the predictive value of a positive early virological response has been validated in the post-transplant setting. Improvement in inflammatory activity after viral eradication is well established, but fibrosis regression or stabilisation is less predictable and factors such as rejection and biliary complications may still contribute to graft loss. Most studies have initiated therapy at least 6 months postoperatively in order to optimise patient tolerance and enable the addition of ribavirin. The use of adjuvant agents to treat drug-induced neutropenia and anaemia in this population is evolving and becoming a crucial part of therapy. Determination of optimal doses of both pegylated interferon and ribavirin, and guidance on when to stop treatment, as well as improving tolerability are important steps in achieving higher response rates and minimising drug toxicity.

Early recurrence of hepatitis C virus infection after liver transplantation

1. Early recurrence of hepatitis C is universal. 2. Typical histopathologic features of hepatitis C virus (HCV) and acute allograft rejection (AAR) exist. 3. Early recurrent HCV may be differentiated from AAR. 4. Liver biopsy plays a role in diagnosing HCV and AAR. 5. Risk factors for recurrent HCV should be known. 6. The natural history of recurrent HCV should be known. 7. The future role of ancillary studies beyond liver biopsy is assessed.

Morphologic Features of Hepatitis C Recurrence in Patients After Orthotopic Liver Transplantation-Preliminary Analysis of our Case Observations

INTRODUCTION

Hepatitis C virus (HCV) recurrence is almost universal in patients after liver transplantation. The diagnosis of reinfection is more difficult than that of a primary process, as shown by our pathomorphologic analysis of cases of HCV recurrence.

MATERIAL

During 5.5 years, 240 liver biopsies included 54 obtained from liver transplant recipients with primary HCV infections, among whom 26 (56.5%) had clinical signs and symptoms of hepatitis. Nineteen patients from this population underwent 30 liver biopsies. In addition, seven biopsies were performed in five patients without clinical signs of reinfection.

RESULTS

In 44.2% of patients with HCV recurrence and 15% without reinfection, the intensity of the primary process in the native livers was assessed as high. Reinfection was found in all patients with liver carcinoma and 67% with hepatocyte dysplasia. Histologic signs of infection were estimated as minimal (n = 4), mild (n = 19), or moderate (n = 4). In five patients with reinfections and one without recurrence, histologic manifestations of acute rejection were also observed. In conclusion, HCV was the indication for liver transplantation in 22.4% cases. Clinical manifestation of recurrence was found in 56.5% of the patients, who tended to be older than those without disease recurrence. Upon microscopy, lobular lesions predominated over the portal changes. Factors predisposing to HCV recurrence were coexistence of other liver disorders, a high intensity of the inflammatory process, hepatocyte dysplasia, and/or hepatocellular carcinoma in the native liver and acute rejection episodes.

Factors associated with the presence of nonalcoholic steatohepatitis in patients with chronic hepatitis C

OBJECTIVES

The aim of this study was to identify factors associated with the presence of nonalcoholic steatohepatitis (NASH) in patients with chronic hepatitis C (CHC).

METHODS

We studied 98 patients with CHC [47 with NASH (group HCV/NASH), 51 without NASH (group HCV)] and 85 with NASH not infected with hepatitis C virus (HCV) (group NASH). We determined factors associated with the presence of NASH in patients with hepatitis C.

RESULTS

Group HCV/NASH patients resembled those with NASH. Body mass index (BMI) was higher in group HCV/NASH than in group HCV, but was similar to group NASH. Most HCV/NASH patients had risk factors for NASH. In patients infected with HCV, NASH and NASH-related lesions were independently associated with BMI, while steatosis score was associated with HCV genotype 3 and BMI. Fibrosis stage was independently associated with steatosis, necroinflammatory activity index, and NASH lesions.

CONCLUSION

While HCV genotype 3 infection and BMI are associated with the presence of steatosis in CHC, BMI is the only factor independently associated with the presence of NASH in these patients. We suggest that overweight-related factors might induce NASH in CHC patients.

Recurrent Hepatitis C in Liver Allografts

RATIONALE AND DESIGN

The accuracy of a prospective histopathologic diagnosis of rejection and recurrent hepatitis C (HCV) was determined in 48 HCV RNA-positive liver allograft recipients enrolled in an "immunosuppression minimization protocol" between July 29, 2001 and January 24, 2003. Prospective entry of all pertinent treatment, laboratory, and histopathology results into an electronic database enabled a retrospective analysis of the accuracy of histopathologic diagnoses and the pathophysiologic relationship between recurrent HCV and rejection.

RESULTS

Time to first onset of acute rejection (AR) (mean, 107 days; median, 83 days; range, 7-329 days) overlapped with the time to first onset of recurrent HCV (mean, 115 days; median, 123 days; range, 22-315 days), making distinction between the two difficult. AR and chronic rejection (CR) with and without co-existent HCV showed overlapping but significantly different liver injury test profiles. One major and two minor errors occurred (positive predictive values for AR = 91%; recurrent HCV = 100%); all involved an overdiagnosis of AR in the context of recurrent HCV. Retrospective analysis of the mistakes showed that major errors can be avoided altogether and the impact of unavoidable minor errors can be minimized by strict adherence to specific histopathologic criteria, close clinicopathologic correlation including examination of HCV RNA levels, and a conservative approach to the use of additional immunosuppression. In addition, histopathologic diagnoses of moderate and severe AR and CR were associated with relatively low HCV RNA levels, whereas relatively high HCV RNA levels were associated with a histopathologic diagnosis of hepatitis alone, particularly the cholestatic variant of HCV.

CONCLUSIONS

Liver allograft biopsy interpretation can rapidly and accurately distinguish between recurrent HCV and AR/CR. In addition, the histopathologic observations suggest that the immune mechanism responsible for HCV clearance overlap with those leading to significant rejection.

Hepatitis C recurrence is not associated with allograft steatosis within the first year after liver transplantation

The natural history of allograft steatosis in hepatitis C (HCV)-infected patients after liver transplantation (LT) is poorly understood. The aim of our study was to determine the relationship of allograft steatosis to HCV recurrence after LT. All patients undergoing LT at our center from March 1998 to December 2001 were included in the study. Explanted liver tissue and liver biopsies performed at 1 week, 4 months, and 12 months were scored for degree of allograft steatosis (0-4), fibrosis (0-6), and modified histological activity index (0-18). One hundred sixty-seven HCV and 235 non-HCV-infected patients (control group) underwent LT. Of these patients, 122 HCV and 154 non-HCV patients had a viable graft at 1 year and were analyzed. Allograft steatosis was present in 40% of HCV patients at 4 months and 36% at 1 year. The incidence of allograft steatosis after LT was similar in HCV-infected and non-HCV-infected patients (P not significant). Age of the donor (P =.041), or higher recipient body mass index (BMI) at the time of LT (P =.015) or at 12 months after LT (P =.041) predicted a higher degree of allograft steatosis at 12 months in the HCV group. Degree of allograft steatosis was not associated with higher fibrosis or necroinflammatory score. In conclusion, there is a similar high incidence of allograft steatosis in HCV and non-HCV-infected patients after LT. A high BMI of the HCV-infected recipient is the best predictor for high degree of allograft steatosis after LT. Allograft steatosis does not predict the severity of HCV recurrence in the first 12 months after LT.

Steatosis accelerates fibrosis development over time in hepatitis C virus genotype 3 infected patients

BACKGROUND/AIMS

Steatosis is common in patients with hepatitis C virus (HCV) infection. Its influence on disease progression is only partially understood. The aim of this study was to evaluate the impact of steatosis on fibrosis progression over time in relation to HCV genotype.

METHODS

We retrospectively analyzed 98 patients who underwent dual liver biopsies prior to antiviral treatment. The median follow-up time was 5.8 years. Biopsy specimens were assessed for necroinflammatory activity, fibrosis and steatosis.

RESULTS

The prevalence and grade of steatosis were strongly associated with HCV genotype 3, independent of sex, age, body mass index and alcohol consumption. Progressive fibrosis was more prevalent in patients whose initial biopsy showed steatosis, an effect seen mainly in genotype 3 infected patients. Low-grade steatosis was observed in overweight patients, but high-grade steatosis was associated with genotype 3, independent of body mass index.

CONCLUSIONS

Our data confirm the association between HCV genotype 3 and steatosis. Furthermore, we showed that steatosis in genotype 3 infected patients is a risk factor for progression of fibrosis. Therefore, patients with genotype 3 and steatosis ought to be recommended for early therapeutic intervention.

Hepatocellular fat accumulation and low serum cholesterol in patients infected with HCV-3a

OBJECTIVES

The aim of this study was to prospectively investigate the prevalence of hepatic steatosis in chronic hepatitis C patients with respect to viral genotype, hepatic iron concentration, total body iron, body mass index, and serum lipid parameters. Furthermore, the effect of hepatitis C virus (HCV) eradication by antiviral therapy on serum cholesterol levels was studied.

METHODS

Hepatocellular fat and hepatic iron were determined in liver biopsies obtained from 137 interferon-naïve patients with chronic hepatitis C (100 men, 37 women, mean age 40.8 +/- 10.7 yr) enrolled in two prospective clinical trials of interferon/ribavirin therapy. Body mass index and fasting cholesterol levels were determined at baseline, during, and after therapy.

RESULTS

Marked steatosis (>20% of fat-containing hepatocytes) was found in 74.5% of patients infected with HCV-3a compared with 17.9% in HCV-1 and 21.7% in HCV-4-infected patients (p < 0.01). Steatosis in HCV-3a-infected patients did not correlate with the body mass index, hepatic iron content, ferritin, or transferrin saturation. At baseline, serum cholesterol was lower in patients infected with HCV-3a (147 +/- 42 mg/dl; p < 0.01) compared with HCV-1 (188 +/- 36) or HCV-4 (172 +/- 35). In contrast to HCV-1- or HCV-4-infected patients, serum cholesterol increased in HCV-3a virological responders at the end of treatment and 6 months after therapy (baseline 146 +/- 38, end of treatment 166 +/- 29, p < 0.05, sustained virological response 200 +/- 34, p < 0.01). However, serum cholesterol remained unchanged in HCV-3a nonresponders.

CONCLUSIONS

Our data suggest that, in addition to inducing steatosis, HCV-3a lowers serum cholesterol. This metabolic effect is fully reversible after successful HCV-3a eradication. This unique property is not shared by other HCV genotypes.

Utilization of acidophil bodies in the diagnosis of recurrent hepatitis C infection after orthotopic liver transplantation

BACKGROUND

The distinction between acute rejection and early recurrent hepatitis C infection (RHCV) in the setting of orthotopic liver transplantation is often difficult. In liver biopsies acidophil bodies and lobular hepatitis are used to suggest a diagnosis of RHCV over rejection, however, the reliability of this practice has not been established. Because portal tract changes in RHCV and rejection often overlap, we sought to determine whether the degree of hepatocyte acidophil body formation seen on liver biopsies could be used to distinguish between these two conditions.

METHODS

Quantification of acidophil bodies was performed on liver biopsies in orthotopic liver transplant patients with RHCV (n = 10), non-hepatitis C orthotopic liver transplant patients with uncomplicated rejection episodes (n = 10) and non-transplant patients with chronic hepatitis C infection (n = 10). Hematoxylin and Eosin stained slides from all three groups were randomized and tissue segments 1.0 cm in length and of variable width (0.04-0.13 cm) were examined at 200x magnification in a blinded fashion by two pathologists in order to quantify the number of acidophil bodies/cm(2). Lobular chronic inflammation was also graded on a 0-3+ scale.

RESULTS

Liver biopsies taken at the onset of RHCV exhibited 606 +/- 101 acidophil bodies/cm(2) (mean +/- standard error of mean, range 200-1390). These counts were significantly greater (P =.0061, paired 2-tailed t-test) than the 241 +/- 53 acidophil bodies/cm(2) (range 80-514) for acute rejection, and the 194 +/- 21 acidophil bodies/cm(2) (range 100-333) for non-liver transplant chronic hepatitis C infection (P =.0013). No difference in lobular inflammation between index RHCV and rejection biopsies was detected.

CONCLUSIONS

Although there is overlap, on average there are twice as many acidophil bodies in the initial stage of RHCV when compared with acute rejection (average of 55 per linear cm in RHCV versus 21 per linear cm for rejection). Lobular inflammation was not a reliable indicator of the initial onset of RHCV.

Hepatitis C virus NS5A colocalizes with the core protein on lipid droplets and interacts with apolipoproteins

The nonstructural protein 5A (NS5A) of the hepatitis C virus (HCV) has been shown to interact with a variety of cellular proteins and implicated in the regulation of cell growth, interferon resistance, and other cellular signaling pathways, but the role of NS5A in HCV pathogenesis has not been firmly established. To further characterize this multifunctional protein, we instigated the studies of the subcellular localization of NS5A in a hepatoma cell line. NS5A was localized to the perinuclear membrane structures, including the endoplasmic reticulum (ER) and the Golgi apparatus, by immunofluorescence staining and confocal microscopy. In addition, it was also associated with the surface of cytoplasmic globular structures when expressed alone or as a part of the NS3-5B polyprotein. Oil red O staining revealed that these globular structures were lipid droplets, where the HCV core protein was also localized. The association of NS5A with intracellular membrane was further confirmed by membrane flotation analysis. To determine whether NS5A interacts with any cellular lipid-binding protein, we performed yeast two-hybrid screening in both HepG2 and human liver cDNA libraries. Apolipoprotein A1 (apoA1), one of the protein components of high-density lipoprotein (HDL) particles, was identified by two independent screening processes. The interaction between NS5A and apoA1 was confirmed by both in vitro pull-down and in vivo coimmunoprecipitation experiments. Immunofluorescence staining revealed a significant colocalization of NS5A and apoA1 in the Golgi apparatus. Our results established an association of NS5A with lipid droplets and apoA1, suggesting that NS5A, together with the core protein, may play a role in the pathogenesis of the derangement of lipid metabolism, contributing to liver steatosis commonly observed in hepatitis C.

Detection of the negative-strand hepatitis C virus RNA in tissues: implications for pathogenesis

The replication of hepatitis C virus (HCV) RNA is believed to occur via its transcription into a complementary, genomic-length RNA, the so-called negative-strand HCV RNA. This is based on the comparison with the replication of other members of the Flaviviridae family. Detection of the negative-strand HCV RNA in human tissues by semi-quantitative, strand-specific RT-PCR has contributed to the understanding of the HCV cell tropism and of the pathogenesis of HCV-associated disease manifestations. In particular, it was shown that the levels of intrahepatic HCV RNA are not correlated to the extent of the necroinflammation, but that a significant correlation was found with the liver steatosis. These results suggest that most liver disease associated with HCV infection is mediated by the host immune response. However, in some patients, most notably those infected with HCV genotype 3, HCV may cause a cytopathic effect, consisting in the lipid accumulation within hepatocytes.

Liver steatosis in chronic hepatitis C: a morphological sign suggesting infection with HCV genotype 3

AIMS

To identify factors associated with liver steatosis in chronic hepatitis C.

METHODS AND RESULTS

Occurrence and severity of liver steatosis in 254 chronic hepatitis C patients were compared with presence of alcohol abuse, body mass index (BMI) >26, history of intravenous drug addiction and hepatitis C virus (HCV) genotype. Steatosis was found in 109 (43%) patients. The occurrence of steatosis was significantly associated with ongoing alcohol abuse (P=0.03) or HCV genotype 3 (P= 0.003), but not with BMI >26. A moderate to severe steatosis was present in 60% of patients infected with HCV genotype 3, irrespective of the presence of alcohol abuse, BMI >26 or history of intravenous drug addiction. Using a multivariable stepwise logistic regression analysis, infection with genotype 3 had an odds ratio (OR) of 10 (95% confidence interval (CI)=4.56-22) for a liver steatosis, whereas the presence of a cirrhosis at histology had an OR=0.256 (95% CI=0.07-0.92).

CONCLUSIONS

A moderate to severe degree of steatosis of the liver is a morphological sign suggestive of infection with HCV genotype 3, independent of other risk factors of a fatty liver, but it may disappear at late stages of the disease.

Hepatitis C-induced hepatic allograft injury is associated with a pretransplantation elevated viral replication rate

Hepatitis C virus (HCV) allograft infection after liver transplantation follows a variable but accelerated course compared with the nontransplantation population. Predictors of outcome and mechanisms of reinfection remain elusive. The accelerated HCV-induced allograft injury associated with a 10- to 20-fold increase in serum viral quantity posttransplantation was hypothesized to be the result of elevated intrahepatic viral replication rates. Patients (N = 23) with HCV-induced end-stage liver disease who underwent liver transplantation between October 1995 and December 1998 were prospectively studied. HCV-induced allograft injury was defined by posttransplantation persistent biochemical hepatitis or allograft fibrosis not explained by other diagnoses. Liver biopsies (N = 92) were obtained by protocol and when clinically indicated. Negative-strand HCV RNA (putative intermediate for replication) was detected by a strand-specific reverse-transcription polymerase chain reaction (RT-PCR) assay and semiquantatively compared with constitutively expressed 18S rRNA. Recipients with increased pretransplantation replication were at increased risk for the development of posttransplantation biochemical hepatitis (P =.03), an increased rate of allograft fibrosis (P =.006), and increased mortality rate (40.0% vs. 0.0%; P =.02). There was no correlation with quantities of genomic HCV RNA in the serum with relative intrahepatic viral replication either before or after liver transplantation. The relative rate of HCV replication within the allograft was not elevated in the posttransplantation period compared with that seen within the explanted liver. Accelerated allograft injury caused by HCV may be predicted by viral replication rates within the explanted liver. The stable intrahepatic replication rate after transplantation suggests that elevated serum viral loads are the result of decreased viral clearance, possibly secondary to immunosuppressive therapy.

Hepatocyte steatosis is a cytopathic effect of hepatitis C virus genotype 3

BACKGROUND/AIMS

Patients infected with the hepatitis C virus (HCV) often have liver steatosis, suggesting the possibility of a viral cytopathic effect. The aim of this study was to correlate the occurrence and severity of liver steatosis with HCV RNA type, level and sequence of the core-encoding region.

METHODS

We scored the liver steatosis in 101 HCV-infected individuals carefully selected to exclude other risk factors of a fatty liver. Results were compared with HCV RNA genotype and level in serum and liver. In selected patients, we assessed the effect of antiviral therapy on steatosis and the relationship between nucleocapsid sequence heterogeneity and fat infiltration.

RESULTS

Steatosis was found in 41 (40.6%) patients, irrespective of sex, age or route of infection. HCV genotype 3 was associated with higher steatosis scores than other genotypes. A significant correlation between steatosis score and titer of intrahepatic HCV RNA was found in patients infected with genotype 3, but not in those infected with genotype 1. In selected patients, response to alpha-interferon was associated with the disappearance of steatosis. Analysis of the nucleocapsid of 14 HCV isolates failed to identify a sequence specifically associated with the development of steatosis.

CONCLUSIONS

We provide virological and clinical evidence that the steatosis of the liver is the morphological expression of a viral cytopathic effect in patients infected with HCV genotype 3. At variance with published evidence from experimental models, the HCV nucleocapsid protein does not seem to fully explain the lipid accumulation in these patients.

Liver transplantation for hepatitis C virus related cirrhosis

Hepatitis C virus (HCV) related chronic liver disease is now the leading cause for liver transplantation in many centres. Virological recurrence is inevitable following liver transplantation. Excellent patient and graft survival are seen in the short-term, equivalent to that in patients transplanted for other causes of liver disease. However, histological evidence of disease recurrence or hepatitis is present in over half the patients within a year of transplantation, although a small percentage develop progressive cholestatic hepatitis with graft loss within a year. Cirrhosis can develop in the first year after transplantation and 28% of patients have evidence of cirrhosis by 5 years. There is little agreement over the factors that predict the recurrence of disease, development of cirrhosis within the graft and graft or patient survival. Graft loss due to HCV occurs in up to 9% at 5 years and the long-term prognosis may not be comparable to groups transplanted for other diseases. Patients with hepatocellular carcinoma may benefit from liver transplantation if the tumour is small and without vascular invasion. There are, as yet, no clear guidelines regarding the best combination of immunosuppressants in patients with HCV but viral clearance has been achieved with the use of interferon and ribavirin therapy post-operatively.

Properties of the hepatitis C virus core protein: a structural protein that modulates cellular processes

The core protein of hepatitis C virus (HCV) is believed to form the capsid shell of virus particles. Maturation of the protein is achieved through cleavage by host cell proteases to give a product of 21 000 MW, which is found in tissue culture systems and sera from infected individuals. However, efficient propagation of the virus is not possible at present in tissue culture. Hence, studies have focused on the properties of the core protein and its possible role in pathologies associated with HCV infection. This review describes key features of the polypeptide and the status of current knowledge on its ability to influence several cellular processes.

Prediction of liver allograft fibrosis after transplantation for hepatitis C virus: persistent elevation of serum transaminase levels versus necroinflammatory activity

Recurrence of hepatitis C virus (HCV) after orthotopic liver transplantation (OLT) remains a significant source of morbidity and mortality. Factors that reliably predict allograft injury from HCV have not been identified. Demographics, clinical data, and histopathological characteristics of recipients with and without persistently elevated serum transaminase levels (PEST) were compared. Twenty-four patients with HCV-induced end-stage liver disease who underwent OLT between October 1995 and December 1998 were entered into a longitudinal, prospective evaluation for identification of parameters associated with graft injury. Liver biopsies were performed preoperatively and between posttransplantation days 1 to 28, 29 to 60, 61 to 180, 181 to 360, and then every 6 to 12 months thereafter. Biopsy specimens were reviewed in a blinded fashion and scored for rejection, necroinflammatory activity, extent of fibrosis, and infiltrating cell type, location, and magnitude. Transplant recipients with PEST (alanine transaminase level >1.5 times normal for 3 consecutive months) and cholestatic hepatitis showed an increased viral load compared with their own preoperative values (16-fold and 256-fold, respectively). Compared with control transplant recipients, PEST was associated with macrovesicular steatosis within 28 days after OLT (P <.05) and showed an increased rate of fibrosis (P <.003) despite similar degrees of rejection and necroinflammatory activity. There was no difference in demographics or immunosuppression. Macrovesicular steatosis may be the earliest predictor of graft fibrosis. Despite similar degrees of necroinflammatory activity, transplant recipients with PEST had an increased rate of fibrosis that could be predicted on average within 6 months posttransplantation.

Pathology of the liver

Among the topics of recent investigation in liver pathology were an examination of normal portal tract structures in needle liver biopsies, computer reconstructions of the intrahepatic biliary tree, identification of oval cells (presumed progeny of hepatic stem cells) in a variety of biliary and nonbiliary diseases and tumors, the features and pathogenesis of nonalcoholic steatohepatitis, and further characterization of proliferating bile ductules. A morphometric study of portal structures in normal needle liver biopsies found that approximately one third in a given specimen may not show a portal vein and that a bile duct may not be seen in 7%. Apoptosis is a critical mechanism for the death of hepatocytes in viral hepatitis and also in endothelial injury in the cold perfusion-warm reperfusion sequence in liver transplantation. The results of two studies examining the relationship of steatosis to chronic hepatitis C virus infection in native and transplanted livers suggest that fatty change is a specific virus-mediated lesion. In the field of hepatic neoplasia, liver cell dysplasia (large cell change), long thought to be a premalignant lesion, was hypothesized to represent abnormal hepatocyte polyploidization.