Changes in blood lipid composition and response to interferon treatment in chronic hepatitis C

Abnormalities of Lipoprotein Levels in Liver Cirrhosis: Clinical Relevance

Progressive lipoprotein impairment occurs in liver cirrhosis and is associated with increased morbidity and mortality. The present review aims to summarize the current evidence regarding the prognostic value of lipoprotein abnormalities in liver cirrhosis and to address the need of a better prognostic stratification of patients, including lipoprotein profile assessment. Low levels of lipoproteins are usual in cirrhosis. Much evidence supports the prognostic role of hypolipidemia in cirrhotic patients. In particular, hypocholesterolemia represents an independent predictor of survival in cirrhosis. In cirrhotic patients, lipoprotein impairment is associated with several complications: infections, malnutrition, adrenal function, and spur cell anemia. Alterations of liver function are associated with modifications of circulating lipids. Decreased levels of lipoproteins significantly impact the survival of cirrhotic patients and play an important role in the pathogenesis of some cirrhosis-related complications.

Interferon Control of the Sterol Metabolic Network: Bidirectional Molecular Circuitry-Mediating Host Protection

The sterol metabolic network is emerging center stage in inflammation and immunity. Historically, observational clinical studies show that hypocholesterolemia is a common side effect of interferon (IFN) treatment. More recently, comprehensive systems-wide investigations of the macrophage IFN response reveal a direct molecular link between cholesterol metabolism and infection. Upon infection, flux through the sterol metabolic network is acutely moderated by the IFN response at multiple regulatory levels. The precise mechanisms by which IFN regulates the mevalonate-sterol pathway—the spine of the network—are beginning to be unraveled. In this review, we discuss our current understanding of the multifactorial mechanisms by which IFN regulates the sterol pathway. We also consider bidirectional communications resulting in sterol metabolism regulation of immunity. Finally, we deliberate on how this fundamental interaction functions as an integral element of host protective responses to infection and harmful inflammation.

Serum cholesterol and statin use predict virological response to peginterferon and ribavirin therapy

Elevated low-density lipoprotein (LDL) levels and statin use have been associated with higher sustained virological response (SVR) rates in patients receiving chronic hepatitis C therapy. However, these relationships have not been well characterized in randomized controlled trials. Furthermore, little is known about the relationship between high-density lipoprotein (HDL) and virological response. To determine whether baseline LDL or HDL levels and statin use affect SVR rates, we retrospectively evaluated the IDEAL (Individualized Dosing Efficacy Versus Flat Dosing to Assess Optimal Pegylated Interferon Therapy) trial, in which 3070 treatment-naive, hepatitis C virus (HCV) genotype 1-infected patients were treated for up to 48 weeks in one of the following arms: (1) peginterferon (PEG-IFN) alfa-2b at 1.5 microg/kg/week with ribavirin (RBV) at 800 to 1400 mg/day, (2) PEG-IFN alfa-2b at 1.0 microg/kg/week with RBV at 800 to 1400 mg/day, or (3) PEG-IFN alfa-2a at 180 microg/week with RBV at 1000 to 1200 mg/day. Virological responses were assessed by pretreatment statin use and baseline elevated LDL levels (> or =130 mg/dL) or low HDL levels (<40 mg/dL for men and <50 mg/dL for women). In 1464 patients with baseline elevated LDL levels or low HDL levels, the SVR rate was significantly higher than that in patients with normal levels (44.9% versus 34.0%, P < 0.001). In 66 patients receiving a statin pretreatment, the SVR rate was higher than the rate of those not receiving it (53.0% versus 39.3%, P = 0.02). In a multivariate logistic regression analysis using the stepwise selection method with baseline characteristics, a high LDL level [odds ratio (OR) = 1.6, 95% confidence interval (CI) = 1.4-1.8, P < 0.001], a low HDL level (OR = 0.5, 95% CI = 0.3-0.8, P = 0.004), and statin use (OR = 2.0, 95% CI = 1.1-3.7, P = 0.02) were independently associated with SVR.

CONCLUSION

Baseline elevated LDL levels or low HDL levels and preemptive statin usage were associated with higher SVR rates. Prospective studies may be considered to explore the biological impact of these factors on HCV RNA replication and treatment response.

Interferon-lambda genotype and low serum low-density lipoprotein cholesterol levels in patients with chronic hepatitis C infection

Recently, genetic polymorphisms occurring in the interferon (IFN)-lambda gene region were associated with response to IFN-based treatment of hepatitis C infection. Both infection with the hepatitis C virus and IFN therapy are associated with decreased serum cholesterol and high cholesterol has been associated with increased likelihood to respond to IFN. We sought to determine if the IFN-lambda gene variant was also associated with serum lipid levels in chronic hepatitis C patients. We compared genotypes of the rs12979860 polymorphism, located proximal to the IL28 gene, with serum lipid and apolipoprotein levels in 746 subjects with chronic hepatitis C virus infection, not currently undergoing treatment, using multivariable analysis of variance. Levels of total cholesterol (P = 6.0 x 10(-4)), apolipoprotein B (P = 1.3 x 10(-6)) and low-density lipoprotein (LDL) cholesterol (P = 8.9 x 10(-10)) were significantly higher in subjects carrying the rs12979860 CC responder genotype compared with those with the CT or TT genotype. Levels of triglycerides (P = 0.03), apolipoprotein A-I (P = 0.06), and apolipoprotein E (P = 0.01) were slightly lower in the rs12979860 CC genotype group, whereas levels of high-density lipoprotein cholesterol (P = 0.78) and apolipoprotein C-III (P = 0.74) did not vary by rs12979860 genotype.

CONCLUSION

Our results suggest that low levels of LDL cholesterol in chronic hepatitis C patients may be a marker of host endogenous IFN response to hepatitis C and that subjects with the rs12979860 CC responder genotype may have a lower endogenous IFN response to the virus.

Association between lipoprotein subfraction profile and the response to hepatitis C treatment in Japanese patients with genotype 1b

Pegylated interferon and ribavirin combination therapy is the standard treatment for patients with chronic hepatitis C (CHC). Some groups have reported a relation between lipid values and response while others have reported that microsomal triglyceride transfer protein, a key enzyme in the assembly and secretion of lipoproteins, was related to hepatitis C virus (HCV). The aim of this study was to investigate the association between the lipoprotein profiles, classified according to size, and hepatitis C treatment and the usefulness for predicting the outcome of treatment. Forty-four patients with CHC (27 men and 17 women) were included in the study. The serum cholesterol and triglyceride (TG) levels in the lipoprotein subclasses were determined using high-performance liquid chromatography with gel permeation columns, which classified lipoproteins into 20 subfractions based on particle size. According to a univariate analysis, those who achieved an sustained viral response (SVR) had a significantly higher serum total cholesterol level, higher cholesterol levels in the low-density lipoprotein subfraction (25.5 nm in diameter) and the very low-density lipoprotein (VLDL) subfraction (44.5 and 36.8 nm), and a higher serum TG level in the VLDL subfraction (44.5 nm), compared with the corresponding values in the non-SVR group. Higher serum cholesterol and TG concentrations in the lipoprotein subfractions were predictive of an SVR to therapy for HCV infection with genotype 1b prior to the start of interferon treatment.

Hepatitis C virus infection and its clearance alter circulating lipids: implications for long-term follow-up

Hepatitis C associated hypolipidemia has been demonstrated in studies from Europe and Africa. In two linked studies, we evaluated the relationship between hepatitis C infection and treatment with lipid levels in an American cohort and determined the frequency of clinically significant posttreatment hyperlipidemia. First, a case-control analysis of patients with and without hepatitis C was performed. The HCV Group consisted of 179 infected patients. The Uninfected Control Group consisted of 180 age-matched controls. Fasting cholesterol, low density lipoprotein (LDL), high density lipoprotein and triglycerides were compared. Next was a retrospective cohort study (Treated Hepatitis C Group) of 87 treated hepatitis C patients with lipid data before and after therapy was performed. In the case-control analysis, the HCV Group had significantly lower LDL and cholesterol than the Uninfected Control Group. In the retrospective cohort, patients in the Treated Hepatitis C Group who achieved viral clearance had increased LDL and cholesterol from baseline compared to patients without viral clearance. These results persisted when adjusted for age, sex, and genotype. 13% of patients with viral clearance had increased LDL and 33% experienced increases in cholesterol to levels warranting lipid lowering therapy.

CONCLUSION

Hepatitis C is associated with decreased cholesterol and LDL levels. This hypolipidemia resolves with successful hepatitis C treatment but persists in nonresponders. A significant portion of successfully treated patients experience LDL and cholesterol rebound to levels associated with increased coronary disease risk. Lipids should be carefully monitored in persons receiving antiviral therapy.

Baseline cholesterol is associated with the response to antiviral therapy in chronic hepatitis C

BACKGROUND

Hepatitis C virus (HCV) partially interacts with low-density lipoprotein (LDL) receptors, suggesting a role for lipids in regulating HCV clearance. Our aim was to study if baseline lipids can discriminate responders from non-responders among patients with HCV infection.

METHODS

A total of 109 HCV patients were studied. Laboratory measurements included serum lipids, aminotransferases and viral load, as well as HCV genotype determinations.

RESULTS

Responders (n = 53) had significantly higher serum baseline levels of total cholesterol, LDL cholesterol and apolipoprotein B compared to non-responders (n = 56). Multivariate logistic regression analysis showed that a 10 mg/dL increase in total cholesterol was associated with 3.02 higher odds of responding to treatment (95% CI 1.74-5.32, P < 0.001), while a 10 mg/dL increase in apolipoprotein B levels was associated with 1.81 higher odds of responding to treatment (95% CI 1.37-2.54, P < 0.001), after adjustment for age, sex, body mass index (BMI), smoking habits, baseline viral load, liver histology and administration of pegylated interferon. An inverse association between BMI and response to treatment was also evident (adjusted odds ratio 0.73, 95% CI 0.55-0.96; P = 0.03).

CONCLUSION

Baseline serum total cholesterol levels and BMI could be helpful in discriminating responders to antiviral therapy among patients with HCV infection.

Transactivating effect of hepatitis C virus core protein: a suppression subtractive hybridization study

AIM

To investigate the transactivating effect of hepatitis C virus (HCV) core protein and to screen genes transactivated by HCV core protein.

METHODS

pcDNA3.1(-)-core containing full-length HCV core gene was constructed by insertion of HCV core gene into EcoRI/BamHI site. HepG2 cells were cotransfected with pcDNA3.1(-)-core and pSV-lacZ. After 48 h, cells were collected and detected for the expression of beta-gal by an enzyme-linked immunosorbent assay (ELISA) kit. HepG2 cells were transiently transfected with pcDNA3.1(-)-core using Lipofectamine reagent. Cells were collected and total mRNA was isolated. A subtracted cDNA library was generated and constructed into a pGEM-Teasy vector. The library was amplified with E. coli strain JM109. The cDNAs were sequenced and analyzed in GenBank with BLAST search after polymerase chain reaction (PCR).

RESULTS

The core mRNA and protein could be detected in HepG2 cell lysate which was transfected by the pcDNA3.1(-)-core. The activity of beta-galactosidase in HepG2 cells transfected by the pcDNA3.1(-)-core was 5.4 times higher than that of HepG2 cells transfected by control plasmid. The subtractive library of genes transactivated by HCV core protein was constructed successfully. The amplified library contained 233 positive clones. Colony PCR showed that 213 clones contained 100-1 000 bp inserts. Sequence analysis was performed in 63 clones. Six of the sequences were unknown genes. The full length sequences were obtained with bioinformatics method, accepted by GenBank. It was suggested that six novel cDNA sequences might be target genes transactivated by HCV core protein.

CONCLUSION

The core protein of HCV has transactivating effects on SV40 early promoter/enhancer. A total of 63 clones from cDNA library were randomly chosen and sequenced. Using the BLAST program at the National Center for Biotechnology Information, six of the sequences were unknown genes. The other 57 sequences were highly similar to known genes.

Host factors and failure of interferon-alpha treatment in hepatitis C virus

Failure of interferon-alpha (IFN-alpha) treatment in patients with chronic hepatitis C virus (HCV) infection is a challenging obstacle for clinical and experimental hepatology. Both viral and host factors have been implicated in reducing responsiveness to IFN-alpha therapy. The role of viral factors has been studied extensively and has been summarized in several review articles; however, much less attention has been paid to host factors. In this paper, we review evidence of host factor involvement in IFN-alpha treatment failure. We discuss possible underlying mechanisms responsible for these effects. Potential therapeutic strategies to enhance the effectiveness of IFN-alpha therapy for HCV are also proposed.

Serum anti-cholesterol antibodies in chronic hepatitis-C patients during IFN-alpha-2b treatment

Previously we detected more than 3 times higher anti-cholesterol antibody (ACHA) levels in HIV positive patients compared to healthy individuals, however, this level significantly decreased during highly active anti-retroviral therapy (HAART). In our present study we examined whether these findings could also be detected in patients with chronic hepatitis C (CHC). We calculated the correlation between the ACHA levels and the C5b-9 complement activation product. 39 patients with CHC were treated with IFN-alpha-2b (Schering-Plough) 5 MU daily for 6 weeks, followed by 5 MU TIW. Serum levels of ACHA and complement activation products were measured with ELISA. Serum HCV RNA was measured by a highly sensitive branched DNA technique before and 3, 6 and 12 months after the beginning of IFN-alpha-2b therapy. 52 healthy persons served as controls. At the onset of treatment ACHA level was significantly (p = 0.0062) higher in patients (40 (24-69) AU/ml) (median (interquartile range)) than in control sera (26 (20-35) AU/ml). In the 26 responder patients ACHA levels decreased to the normal level during the therapy, but no change was observed in the 13 non-responders. In patients with a sustained response ACHA levels remained low till the end of the 12 months IFN treatment. ACHA levels were significantly (p = 0.0422) higher in the patients with low (< 4.0 mmol/l) than in those with normal (> or = 4.0 mmol/l) cholesterol concentrations. The ACHA level before the therapy strongly correlated (r = 0.5499, p = 0.0014) with C5b-9 serum levels. ACHA levels are elevated in CHC, but this elevation is not as high as in HIV. Decrease of viral load by IFN-alpha-2b treatment in the responders results in normalization of ACHA concentration. High ACHA levels in patients with low serum cholesterol concentration suggest that high ACHA levels may contribute to the decrease in cholesterol levels. The correlation between the ACHA and C5b-9 levels indicate, that the ACHA may play a role in the complement activation in CHC.

Hepatitis C virus-associated hypobetalipoproteinemia is correlated with plasma viral load, steatosis, and liver fibrosis

OBJECTIVES

A relationship between chronic hepatitis C virus (HCV) infection and lipid metabolism has recently been suggested. The aim of this study was to determine the correlation between lipid profile and virology, histologic lesions, and response to alpha interferon therapy in noncirrhotic, nondiabetic patients with hepatitis C.

METHODS

A total of 109 consecutive untreated chronic hepatitis C patients were studied to assess the following: 1) the effects of HCV genotype, viral load, steatosis, hepatic fibrosis, and body mass index (BMI) on lipid profile; and 2) whether lipid parameters could predict response to antiviral therapy.

RESULTS

The control group showed a significantly higher apolipoprotein B (apoB) concentration compared with patients with chronic hepatitis C. Hypobetalipoproteinemia (apo B <0.7 g/L) was found in 27 (24.7%) chronic HCV patients and in five (5.3%) control subjects (p = 0.0002). Levels of apo B were negatively correlated with steatosis and HCV viral load (r = -0.22; p = 0.03). This last correlation was strong for non-1 genotype and genotype 3 (r = -0.48; p = 0.0005, and r = -0.47; p = 0.007, respectively) but was not found in genotype 1. In multivariate analysis, low apo B concentration was significantly associated with fibrosis grade 2 or 3 versus grade 0 or 1 (p < 0.001), steatosis >5% (p < 0.001), low body mass index (p < 0.001), and high HCV viral load (p < 0.014). No correlation was found in the 76 treated patients between apo B and response to interferon therapy.

CONCLUSIONS

In chronic HCV patients, hypobetalipoproteinemia occurs already in the early stages of HCV infection before the development of liver cirrhosis. The correlation between apo B levels and HCV viral load seems to confirm the interaction between hepatitis C infection and beta-lipoprotein metabolism.

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.

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.

C5b-9 and interleukin-6 in chronic hepatitis C. Surrogate markers predicting short-term response to interferon alpha-2b

BACKGROUND

Available data and our observations suggest that elevated levels of interleukin (IL)-6 and -10 and some complement parameters may be associated with a poor response to IFN alpha. We evaluated how baseline levels of C5b-9, IL-6, and IL-10 influence the outcome of IFN alpha treatment.

METHODS

Fifty-one patients with established chronic hepatitis C were enrolled and treated with IFN alpha-2b. Before and after a 12-week-IFN-treatment (3 MU or 5 MU tiw) serum levels of IL-6, IL-10, C5b-9 and RNA of hepatitis C virus (HCV) were assessed. Sera of 46 sex- and age-matched, healthy blood donors served as control.

RESULTS

While two-thirds of patients was considered 'responder', 14 patients had no significant decrease either in HCV RNA or in ALT levels. In the responder's group lower baseline levels of IL-6 and C5b-9 were found than those in the 'non-responder' group. As a result of IFN therapy HCV RNA and C5b-9 levels significantly decreased. While the serum concentration of IL-6 increased during the follow-up period, regarding IL-10, no change was observed. In patients with 'low' baseline levels of C5b-9 (<2053 ng/ml) IFN alpha resulted in a significantly (P = 0.0005) higher decrease in HCV RNA level. Regarding 'low' IL-6 values (< 1.47 pg/ml) similar but somewhat less significant (P = 0.0039) difference was found if the change of HCV RNA was investigated. The odds ratio of patients with low IL-6 and/or C5b-9 to responding to IFN alpha treatment was almost 10 times (CI: 9.1 (1.8-50.9)) higher as compared with patients without 'low' levels of these parameters.

CONCLUSION

Our data suggest that serum level(s) of IL-6 and/or C5b-9 taken prior to the initiation of IFN treatment may serve as surrogate marker(s) in evaluating patients with chronic hepatitis C whether to get IFN alpha in monotherapy or to consider having combination therapy in the form of IFN alpha-ribavirin.

Lipoprotein changes in patients with chronic hepatitis C treated with interferon-alpha

OBJECTIVE

The aim of this study was to evaluate the effects of interferon-alpha therapy on the lipid profile of patients with chronic hepatitis C.

METHODS

In 36 consecutive patients with chronic hepatitis C, fasting lipoproteins were evaluated prospectively at baseline, 1, 3 and 6 months during interferon-alpha therapy and 3 months after the end of treatment.

RESULTS

During interferon-alpha therapy, there was a progressive increase in total and very low density lipoprotein (VLDL)-triglycerides, VLDL-cholesterol and a sustained raise in apolipoprotein (apo) B. In parallel, there was a reduction in high density lipoprotein (HDL)-cholesterol and apo A1 levels. In contrast, total and low density lipoprotein (LDL)-cholesterol and lipoprotein (a) levels remained essentially unchanged during interferon-alpha therapy. Three patients developed chylomicronemia, two of them with severe hypertriglyceridemia, although none of them presented with pancreatitis. Chylomicronemia and severe hypertriglyceridemia were more common in patients with basal triglycerides above 200 mg/dl. Nineteen patients responded to interferon-alpha therapy, but their lipid profile did nor differ from that of nonresponders. Three months after the end of interferon-alpha therapy lipid changes subsided, although VLDL and HDL-cholesterol and apo B did not reach basal levels.

CONCLUSION

In patients with chronic hepatitis C, interferon-alpha therapy is associated with an increase of total and VLDL-triglycerides, VLDL-cholesterol and apo B, and a decline of HDL-cholesterol and apo A1. The development of chylomicronemia and severe hypertriglyceridemia in some cases makes mandatory a close monitoring of triglycerides during interferon-alpha therapy, particularly among patients with increased triglycerides at baseline.

Relationship among hepatic inflammatory changes, circulating levels of cytokines, and response to IFN-alpha in chronic hepatitis C

To investigate the relationship among circulating cytokines, inflammation in the liver, and kind of response to interferon-alpha (IFN-alpha) in hepatitis C, we studied 63 consecutive patients (38 male, 25 female), treated with IFN for up to 1 year. Serum tumor necrosis factor-alpha (TNF-alpha) was measured at baseline and after 3 months of treatment. Transient (TR) or sustained response (SR) was observed in 29 and 16 patients, respectively. Baseline levels of TNF < or = 22 ng/L were observed in 69% of patients with SR, 55% of patients with TR, and 22% of nonresponders (p < 0.01). There was a significant correlation between baseline TNF levels and histologic grading score of hepatitis (p < 0.01). After 3 months of treatment, TNF levels >22 ng/L were observed in 63% of patients with SR, 69% of patients with TR, and 83% of nonresponders (p NS). Independent of the treatment outcome, TNF levels were lower at baseline and increased significantly with treatment in patients with lower histologic grading (p < 0.005). In conclusion, in patients with chronic hepatitis C, circulating TNF levels correlate with the degree of inflammation in the liver. Response to IFN is accompanied by an inflammatory response involving the release of TNF.

Review article: interferon and hepatitis C--factors predicting therapeutic outcome

Hepatitis C chronically infects approximately 1.5% of Americans and is the most common clinical problem facing hepatologists. Since the virus was initially described in 1989, development of an effective therapy has been challenging. Although several different therapeutic agents have been used, no therapy has been shown to reliably eradicate the virus. Interferon-alpha, a cytokine with immunostimulatory and anti-viral properties, has become the therapy of choice for patients with chronic hepatitis C infection. Trials assessing the efficacy of interferon-alpha have characterized host and viral factors predictive of responses to treatment. A thorough understanding of these predictive factors is requisite to providing cost-effective therapeutic decisions for the patient with chronic hepatitis C infection.

Blood lipids of patients with chronic hepatitis: differences related to viral etiology

In order to investigate whether a difference might exist in blood cholesterol and its subtractions between patients with chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection, serum cholesterol, HDL-cholesterol, triglycerides and common liver function tests were measured in 138 patients (92 male, 46 female) with biopsy-proven chronic viral hepatitis without cirrhosis. Twenty-four had hepatitis B and 114 hepatitis C. Mean serum cholesterol was lower in HCV-infected in comparison to HBV-infected patients (175 +/- 36 mg/dl vs. 189 +/- 28 mg/dl, p < 0.05). On multivariate analysis, etiology of hepatitis appeared to be associated with the value of serum cholesterol, independently of age, sex and liver synthetic function (improvement of chi-square 4.40, p < 0.05). In patients with HBV infection, circulating tumor necrosis factor-alpha demonstrated a correlation with serum triglycerides (p = 0.618) and an inverse correlation with serum HDL-cholesterol (p = -0.456); in the group of patients with HCV infection, interleukin-6 correlated with triglycerides (p = 0.370) and HDL-cholesterol (p = -0.355). Thus, differences in the mechanisms of liver damage and of viral clearance in hepatitis C in comparison to hepatitis B, reflected in these patients by the levels of circulating cytokines, may be mirrored by differences in their blood lipid composition.

Hepatitis C virus core protein shows a cytoplasmic localization and associates to cellular lipid storage droplets

There is now abundant evidence to substantiate an important role of hepatitis C virus (HCV) core protein in cellular gene expression as well as in the viral cycle. Thus the subcellular localization of this protein has important implications. However, several studies have shown controversial results: the HCV core has been, indeed, described as cytoplasmic or nuclear depending on the size of the protein or on the genotype analyzed. We have studied the localization of the HCV core protein in two different cell lines, one nonhepatic (CHO) and the other hepatic (HepG2). Double immunofluorescence staining using a nuclear membrane marker and confocal analysis showed the core protein pattern to be cytoplasmic and globular. This pattern is not cell cycle-regulated. Electron microscopy analysis revealed the nature of the globular staining observed in immunofluorescence. The HCV core protein accumulated at the surface of lipid droplets that were also the unique morphological feature of nonhepatic core transfected cells. The lipid droplets were isolated by sequential ultracentrifugation on the basis of their density; biochemical analysis revealed a prevalence of triglycerides. In addition the core protein colocalized with apolipoprotein AII at the surface of the lipid droplets as revealed by confocal microscopy. Moreover analysis of liver biopsies from chronically HCV-infected chimpanzees revealed that HCV core is cytoplasmic and localized on the endoplasmic reticulum and on lipid droplets. These results clearly define the subcellular localization of the HCV core protein and suggest a relationship between the expression of the HCV core protein and cellular lipid metabolism.