Hemodialysis prevents liver disease caused by hepatitis C virus: role of hepatocyte growth factor

Simple blood tests as noninvasive markers of liver fibrosis in hemodialysis patients with chronic hepatitis C virus infection

HCV infection is common among patients with end-stage renal disease (ESRD) on hemodialysis, and it has been considered an independent risk factor for mortality in this setting. Although liver biopsy in ESRD patients with HCV infection is useful before kidney transplantation, it carries a high risk of complications. We sought to assess the diagnostic value of noninvasive markers to stage liver fibrosis in 203 ESRD HCV-infected patients. Univariate and multivariate analysis were used to identify variables associated with significant fibrosis (METAVIR F2, F3, or F4 stages). Significant liver fibrosis was observed in 48 patients (24%). Logistic regression analysis identified AST and platelet count as independent predictors of significant fibrosis (P < 0.001 and P = 0.001, respectively). The area under the receiver operating characteristic curve of the AST to platelet ratio index (APRI) for predicting significant fibrosis was 0.801. An APRI < 0.40 accurately identified patients with fibrosis stage 0 or 1 in 93% of the cases (NPV = 93%), and all misclassified subjects were F2. A cutoff > or = 0.95 to confirm significant fibrosis had a PPV of 66%. If biopsy indication was restricted to APRI scores in the intermediate range (> or = 0.40 and < 0.95), 52% of liver biopsies could have been correctly avoided.

CONCLUSION

Stage of liver fibrosis can be reliably predicted in ESRD HCV-infected subjects by simple and widely available blood tests such as AST levels and platelet count. These tests might obviate the requirement for a liver biopsy in a significant proportion of those patients.

Hepatitis C in chronic kidney disease: predialysis patients present more severe histological liver injury than hemodialysis patients?

BACKGROUND

The characteristics of hepatitis C virus (HCV) infection in predialysis patients are poorly understood and they could be different from hemodialysis patients.

AIMS

To evaluate the demographics, laboratory and histological characteristics of chronic HCV infection in predialysis patients and to compare them with those observed in hemodialysis patients.

METHODS

Thirty-nine predialysis patients with chronic HCV infection were compared to HCV-infected hemodialysis patients (ratio of 1:3) in terms of demographics, laboratory and histological characteristics. The fibrosis progression rate (FPR) was calculated as the ratio between fibrosis stage and duration of infection.

RESULTS

Predialysis patients were older (57 +/- 10 vs. 45 +/- 12 years; p < 0.001), presented a higher proportion of elevated alanine aminotransferase (71.8 vs. 41.0%; p = 0.001) and aspartate aminotransferase (64.1 vs. 26.5%; p < 0.001), a higher proportion of interface hepatitis (66.7 vs. 47%; p = 0.033) and more advanced fibrosis (71.8 vs. 16.2%; p = 0.001). Among patients with estimated duration of infection, predialysis patients presented a longer duration of infection (22 vs. 6 years; p < 0.001) and no difference in FPR was observed between groups (p = 0.692).

CONCLUSION

Although predialysis patients with HCV infection present more severe histological injury than hemodialysis patients, this finding probably reflects a longer duration of infection with no evidence supporting that hepatitis C presents a more aggressive course in this group.

Is hepatitis C more aggressive in renal transplant patients than in patients with end-stage renal disease?

BACKGROUND

The eventual impact of immunosuppression on the natural history of hepatitis C virus (HCV) infection in patients with end-stage renal disease (ESRD) is still unknown because of the lack of comparative data for HCV-infected patients with ESRD and renal transplant patients. The aim of this study was to compare the biochemical and histological characteristics of chronic HCV infection in renal transplants patients and ESRD patients undergoing hemodialysis.

METHODS

Thirty-eight renal transplant patients and 38 ESRD patients undergoing hemodialysis who were chronically infected with HCV and were matched for gender, age at infection, and estimated time of infection were included in the study. The groups were compared regarding laboratory and histological variables.

RESULTS

Renal transplant patients showed similar alanine aminotransferase and higher gamma-glutamyltransferase levels (P = 0.05) when compared with ESRD patients. Comparative analysis of histological variables revealed a higher proportion of cases with septal fibrosis (P = 0.04) and confluent necrosis (P = 0.01) among transplant-recipient patients. No difference between groups was observed regarding the intensity of portal and periportal inflammatory infiltrates. Steatosis was more prevalent among transplant-recipient patients (P < 0.001). There was no difference between groups regarding the prevalence of lymphoid aggregates or bile duct injury.

CONCLUSION

Renal transplant patients had a larger proportion of cases with septal fibrosis and confluent necrosis than did ESRD patients, suggesting that renal transplantation might modify the natural history of hepatitis C in ESRD patients, leading to a more aggressive liver disease.

Determination of the cut-off value of serum alanine aminotransferase in patients undergoing hemodialysis, to identify biochemical activity in patients with hepatitis C viremia

BACKGROUND

Elevated liver enzymes are infrequent in patients with hepatitis C virus (HCV) infection undergoing chronic hemodialysis (HD), suggesting that the alanine aminotransferase (ALT) is a poor predictor of hepatocellular damage in this population.

OBJECTIVE

To establish a more appropriate cut-off value of ALT to identify biochemical activity due to HCV infection in HD patients.

STUDY DESIGN

A total of 217 patients, with an average age of 51.2 years, were evaluated between January and October 2002; 130 were males (60%). Serum ALT was measured by a kinetic method in five consecutive monthly blood samples, from which an average was obtained and divided by the upper limit of normal (ULN). HCV antibodies were determined using an enzyme immunoassay, the serum HCV-RNA by nested-PCR and HCV genotype by hybridization of the amplified sequence from the 5'-non-coding region. The cut-off value of ALT was obtained from a ROC curve.

RESULTS

Within the 217 patients, 18 (8.3%) were anti-HCV-positive, 17 (7.8%) of whom were also HCV-RNA-positive. Genotype distribution was: 1a=47%; 1b=18%; 3a=35%. Mean ALT/ULN (0.77+/-0.57) of the 18 anti-HCV-positive cases was higher (p<0.001) than the negative group (0.38+/-0.23). The mean ALT/ULN (0.81+/-0.57) of the 17 HCV-RNA-positive cases was also higher (p<0.0001) than the negative cases (0.37+/-0.23). The cut-off value of ALT to distinguish the anti-HCV-positive from negative patients was 0.50% or 50% of the ULN (sensitivity=67%; specificity=83%). According to the HCV-RNA, the cut-off value of ALT was 0.45% or 45% of the ULN (sensitivity=71%; specificity=80%).

CONCLUSION

Reducing the cut-off of ALT by half, enables a better identification of biochemical activity in patients with HCV infection on chronic HD.

Clinical presentation of chronic hepatitis C in patients with end-stage renal disease and on hemodialysis versus those with normal renal function

BACKGROUND

The natural history of chronic hepatitis C (CHC) remains to be defined in patients with end-stage renal disease (ESRD).

AIMS

To determine the clinical presentation of CHC and the factors associated with stage III-IV fibrosis in patients with CHC and ESRD.

METHODS

The study included patients with CHC and ESRD (n = 91) or normal renal function (NRF, n = 159). Both groups were matched for mean age, gender, history of alcohol use, and estimated duration of hepatitis C virus (HCV) infection.

RESULTS

Presentation of CHC and ESRD was independently associated with non-Caucasian ethnicity (OR = 3.24, p= 0.0003), a history of diabetes mellitus (DM, OR = 7.911, p < 0.0001), and lower frequencies of being obese (OR = 0.457, p= 0.035), of having hepatic steatosis (OR = 0.372, p= 0.003), and stage III-IV fibrosis (OR = 0.403, p= 0.016). After adjusting for serum levels of alpha-fetoprotein (AFP) and HCV RNA, CHC, and ESRD were independently associated with lower frequencies of elevated alanine aminotransferase (ALT, OR = 0.175, p= 0.02) and aspartate aminotransferase (AST, OR = 0.169, p= 0.04), but higher frequencies of AST/ALT ratio >1 (OR = 7.173, p= 0.002) and hypoalbuminemia (OR = 9.567, p= 0.0007). Compared to patients with NRF and stage III-IV fibrosis, those with ESRD and stage III-IV fibrosis had a significantly higher frequency of a history of DM (OR = 8.014, p= 0.0031) and lower frequency of elevated AST (OR = 0.054, p= 0.004), which were independent of the frequencies of lower levels of ALT and albumin, and AST/ALT ratio >1. In patients with CHC and ESRD, the presence of stage III-IV fibrosis was significantly associated with hepatic steatosis (OR = 4.523, p= 0.012) and thrombocytopenia (OR = 4.884, p= 0.044), which were independent of the frequencies of a history of DM, splenomegaly, and a higher level of AST.

CONCLUSIONS

CHC and ESRD are independently associated with a higher frequency of a history of DM, but lower frequencies of being obese, and having hepatic steatosis, stage III-IV fibrosis, and elevated transaminases. In patients with CHC and ESRD, stage III-IV fibrosis is not associated with a history of DM, but is independently associated with hepatic steatosis and thrombocytopenia.

Lack of Impact of Hepatitis C Virus Coinfection in End-Stage Renal Disease Patients With Hepatitis B Virus Infection

INTRODUCTION

Hepatitis B virus (HBV) and hepatitis C virus (HCV) coinfection results in more severe forms of liver disease in nonuremic patients; however, the impact of HCV coinfection is not clearly known in end-stage renal disease (ESRD) patients with HBV infection. We sought to determine the impact of HCV coinfection in HBV-infected ESRD patients.

PATIENTS AND METHODS

The HBsAg-positive ESRD patients evaluated between March 1999 and May 2003 were divided into two groups: group B, HBV infection alone, and group BC, HBV-HCV coinfection (anti-HCV-positive). Both groups were compared regarding epidemiological, laboratory, and histological findings. A liver biopsy was obtained in cases with evidence of viral replication and/or elevated alanine aminotransferase.

RESULTS

One hundred patients (73% men) with mean age of 42 +/- 11 years (55 patients in group B and 45 in group BC) were studied. Comparison between groups showed a difference in time on hemodialysis and duration of infection, which were higher in group BC (P < .001 and P = .001, respectively) and in history of blood transfusion, which was also more frequent in group BC (P = .04). Liver biopsies, obtained from 15 patients in group B and 28 patients in group BC, showed no difference in frequency of septal fibrosis (60% in group B vs 48% in group BC, P = .46) or interface hepatitis (73% vs 71%, P = .99).

CONCLUSIONS

HBV-HCV coinfection was related to a longer time on hemodialysis, longer duration of infection, and history of blood transfusion. Contrary to nonuremic patients, HCV coinfection was not associated with more severe forms of liver disease in ESRD patients.

[Identification of the cutoff value for serum alanine aminotransferase in hepatitis C screening of patients with chronic renal failure on hemodialysis]

The patients with chronic renal failure in hemodialysis present low levels of serum alanine aminotransferases. In order to establish a better cutoff value for ALT in hepatitis C screening of hemodialysis patients, the ALT levels were measured monthly in 235 patients, being excluded those that presented average above the upper limit of normality. The cutoff value was identified by construction of a ROC curve (receiver operating characteristic). Among 202 patients, 15 (7.4%) presented antibodies to hepatitis C virus (anti-HCV) and 187 (92.6%) were anti-HCV negative, with an ALT average of 0.7 and of 0.5 from ULN (p <0.0001), respectively. The better cutoff value for ALT was at 0.6 from ULN, with sensitivity of 67% and specificity of 75% in anti-HCV screening. These results suggest that ULN of ALT could be reduced for 60% from conventional limit, when we are evaluating patients with CRF in hemodialysis.

Activation of hepatocyte growth factor/activin A/follistatin system during hemodialysis: Role of heparin

BACKGROUND

Hepatocyte growth factor (HGF), activin A, and follistatin compose an organotrophic system that may be modulated by heparin. We prospectively studied the effects of unfractionated heparin (UFH) versus low-molecular-weight heparin (LMWH) enoxaparin-anticoagulated hemodialysis on plasma levels of the cytokines.

METHODS

The factors were measured by immunoassays in 25 chronic hemodialysis patients at the start and at 10 and 180 minutes of the hemodialysis procedure anticoagulated with bolus enoxaparin. Then, the patients were randomized to either receive a bolus and infusion of UFH or to continue LMWH, and were reexamined after 12 weeks.

RESULTS

Predialysis HGF and follistatin were increased (both P < 0.0001), while activin A was normal in hemodialysis patients. Baseline HGF directly correlated with activin A in hemodialysis subjects (P=0.004). In healthy controls, it was positively associated with follistatin (P=0.001). Both HGF and activin A were markedly increased at each interval of enoxaparin-anticoagulated hemodialysis, and follistatin was increased at 10 minutes (all P < 0.0001). The early increments in HGF and follistatin directly depended on the dose of enoxaparin (both P < 0.030). Remarkably, the rise in activin A was inversely associated with the predialysis level of the cytokine (P < 0.0001). The actions of UFH resembled those of LMWH, although the releasing effects on the growth factors were not dose-dependent. The switch from LMWH to UFH resulted in a significant increase in over-dialysis HGF, a fall in follistatin, and no change in activin A.

CONCLUSION

HGF/activin A/follistatin system is activated and disturbed in chronic hemodialysis patients, including depletion of tissue stores of activin A. Type and dose of heparin used during hemodialysis procedures profoundly influence this pleiotropic system, and may thus modulate vital body functions and course of critical diseases.

Changes in viremia and circulating interferon-alpha during hemodialysis in hepatitis C virus-positive patients: only coincidental phenomena?

BACKGROUND

It has been hypothesized that hemodialysis (HD) treatment per se can preserve patients from an aggressive course of hepatitis C virus (HCV) infection by reduction of viral load. The aim of the present study in HCV-positive (HCV+) HD patients is to determine whether HD induces the production of interferon-alpha (IFN-alpha) and if such production can contribute to viremia reduction.

METHODS

To address this issue, HCV RNA and IFN-alpha levels were determined in 11 HCV+ patients immediately before and at the end of a 4-hour dialysis session using cellulosic membranes and 24 and 48 hours later, ie, immediately before the subsequent dialysis session using the same membrane and at the end of the dialysis session. The same protocol was repeated 1 week later using a high-biocompatibility synthetic membrane.

RESULTS

HCV titer decreased in all patients after dialysis (range, 3% to 95%; P = 0.001) and thereafter progressively increased and returned to basal levels within 48 hours, with a new reduction during the next dialysis treatment. There was no significant difference in the magnitude of changes in HCV titers in tests performed using cellulosic or synthetic membranes. Plasma IFN-alpha levels increased markedly after dialysis using both cellulosic (in 9 of 11 cases) and synthetic membranes (in 10 of 11 cases; P < 0.01) and returned to basal levels within 48 hours; thereafter, IFN-alpha levels increased again during the next dialysis session. In some patients, plasma IFN-alpha levels after HD were approximately 50% of the level observed after therapeutic administration of 6 million units of IFN-alpha to 4 HD patients with chronic hepatitis.

CONCLUSION

Although without a proven direct cause-effect relationship between HCV level reduction and induction of IFN-alpha after dialysis, our observation suggests an additional new mechanism for the unusually mild course of HCV infection in HD patients.

Relations between oxidative stress, hepatocyte growth factor, and liver disease in hemodialysis patients

BACKGROUND

Hepatocyte growth factor (HGF) and copper/zinc superoxide dismutase (Cu/Zn SOD) protect against tissue injury, including that due to oxidative stress (SOX). We studied whether they could be associated with each other, SOX markers, prevalence of viral hepatitis, and cardiovascular disease (CVD) and their laboratory surrogates in maintenance hemodialysis (HD) patients.

METHODS

In 24 patients, pre-dialysis serum HGF, plasma Cu/Zn SOD, total lipid peroxides, and serum autoantibodies against oxidized LDL were measured by ELISAs. Viral hepatitis B and C markers were determined by third generation microparticle ELISAs, and CVD was identified on a clinical basis.

RESULTS

In HD patients, circulating HGF, Cu/Zn SOD, and the other SOX markers were higher than in healthy controls, and HGF directly correlated with Cu/Zn SOD levels (P = 0.0006). Both HGF (P = 0.021) and Cu/Zn SOD (P=0.017) were positively associated with prevalence of viral hepatitis and serum alanine aminotransferase activity (P = 0.021 and P=0.040, respectively). Presence of CVD directly correlated with HGF (P = 0.001) but not with Cu/Zn SOD levels (P = 0.087). Circulating HGF positively related to serum C-reactive protein (P = 0.043). In patients without viral hepatitis and CVD, both HGF and Cu/Zn SOD were lower than in those with, and higher than in healthy controls. CVD (P = 0.003) and viral hepatitis (P = 0.024) were independent predictors of increased HGF, while positive viral hepatitis marker predicted increased Cu/Zn SOD levels (P = 0.019) in HD patients. There were no associations between HGF and the SOX markers in controls.

CONCLUSIONS

In maintenance HD patients, circulating Cu/Zn SOD and HGF levels are increased, likely as a part of the reparatory reaction against liver damage. Viral hepatitis status and liver function should be considered in further studies of Cu/Zn SOD in these subjects.

Characteristics of hepatitis C in renal transplant candidates

GOALS

To characterize hepatitis C in renal transplant candidates and to compare hepatitis C-related liver disease between patients with end-stage renal disease (ESRD) and well-matched control subjects without renal disease.

BACKGROUND

Hepatitis C is common in dialysis patients and can cause morbidity and mortality in renal transplant recipients. Patients with advanced hepatitis C often are excluded from renal transplantation.

STUDY

Forty-six renal transplant candidates and 46 control subjects matched for age, sex, and race without renal disease were included. Demographic, laboratory, and histologic data were compared between patients with ESRD and control subjects.

RESULTS

Alanine aminotransferase levels were significantly lower in patients with ESRD (p < 0.001). Hepatitis C virus RNA levels were similar between groups. Patients with ESRD had less inflammatory activity (p < 0.001) and a lower proportion of bridging fibrosis or cirrhosis (13%) than control subjects (30%, p = 0.043). Clinical and laboratory features did not predict histologic grade or stage of hepatitis C in patients with ESRD. Two complications of percutaneous liver biopsy occurred per three diagnoses of cirrhosis in patients with ESRD. No complications occurred with transjugular liver biopsy in this group.

CONCLUSIONS

Patients with ESRD had less severe hepatitis C than did control subjects. Clinical measurements did not predict histologic findings in renal transplant candidates. Transjugular liver biopsy should be considered to stage hepatitis C in renal transplant candidates due to the risk of percutaneous biopsy in uremic patients.

Serum hepatocyte growth factor is associated with viral hepatitis, cardiovascular disease, erythropoietin treatment, and type of heparin in haemodialysis patients

BACKGROUND

Increased serum hepatocyte growth factor (HGF) level is a part of the counter-system against tissue damage and predicts mortality in maintenance haemodialysis (HD) patients. We studied which of the common co-morbid and clinical conditions, and surrogates of metabolic disorders or specific organ damage determine HGF levels in these subjects.

METHODS

In 86 patients, pre-dialysis serum HGF, soluble endothelial markers--such as thrombomodulin (TM), von Willebrand factor and plasminogen activator inhibitor-1--and hepatitis B and C markers were measured by ELISAs. Inflammatory reactants such as C-reactive protein (CRP), alpha(1)-antitrypsin, alpha(1) acid-glycoprotein, and immunoglobulin M and G were assayed by nephelometry, and lipoprotein(a) was determined by ELISA. Cardiovascular disease (CVD) was identified on a clinical basis.

RESULTS

Serum HGF was directly associated with the presence of viral hepatitis, alanine aminotransferase and TM levels, time on HD, the presence of CVD, CRP and alpha(1)-antitrypsin levels, use of unfractionated heparin (UFH) (vs enoxaparin) during HD, dose of UFH, use of recombinant erythropoietin (rHuEpo) treatment, and Kt/V. In 36 patients not treated with rHuEpo, HGF directly correlated with haemoglobin, but not with endogenous Epo levels. There was no association between HGF and the other endothelial and inflammatory markers, gender, age, smoking, cause of renal failure, body mass index, normalized protein catabolic rate, dialysate buffers, dialysers, blood pressure, antihypertensive treatment, leukocyte and platelet counts, albumin, fibrinogen, lipoprotein(a), markers of iron and calcium-phosphorus metabolism, or metabolic acidosis. Positive viral hepatitis markers, prevalent CVD and rHuEpo treatment (in descending order of significance) were independent predictors of high HGF level. In another 20 HD patients, a 4-week course of rHuEpo treatment resulted in a significant 17% increase in circulating HGF levels.

CONCLUSION

Serum HGF levels in HD patients are determined by inflammatory conditions such as viral hepatitis and CVD, increase in response to rHuEpo treatment, and may be influenced by type and dose of heparin used during HD procedures.

Spectrum of liver damage and correlation with clinical and laboratory parameters in HCV infected hemodialysis patients

There are conflicting results in studies concerning the best marker for liver histopathological features of HCV infection in HD patients. We planned a prospective study to follow HCV viremia and laboratory parameters of HD patients and correlate these with clinic features and histopathological findings. We included 68 HCV infected patients (45 male, 23 female, age: 39.8 +/- 11.9 years, HD duration: 58.2 +/- 36.4 months) in our study. The follow-up period after the biopsy was 33.2 +/- 20.3 months. Patients liver enzyme (alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyl transferase (GGT)) levels were determined monthly and ferritin levels every three months, and the mean value was recorded. We also screened patients for HCV RNA. During the follow-up period, 22 (32.4%) of the patients had positive RNA, 26 (38.2%) negative RNA. 20 (29.4%) had intermittent RNA positivity. The patients with high grade of portal necroinflammatory activity had significantly higher AST and ALT levels. In addition patients with high grade lobular activity had significantly shorter HD and HCV infection duration and higher AST, ALT and ferritin levels. AST levels were negatively correlated with duration of HD and HCV infection, and positively correlated with GGT and ferritin levels. Additionally, we found that ALT levels were negatively correlated with HD duration and positively correlated with GGT levels. ALT levels higher than 30 U/L were reflected necroinflammatory activity more significantly than levels higher than 40 U/L. Cirrhosis was detected in 5.9% of the patients, and we could not find any laboratory parameter that was correlated with stage of fibrosis. Although there is a high degree of liver involvement, cirrhosis is a relatively less frequent finding in HD patients. Serum aminotransferases and ferritin levels but not the pattern of HCV viremia are predictors of necroinflammatory activity in liver biopsy specimens. Liver biopsy obligatory to assess the disease activity in HD patients.

Acute changes in plasma levels of hepatocyte growth factor during low-density lipoprotein apheresis

Hepatocyte growth factor (HGF) is a mesenchyme-derived pleiotropic factor, and angiogenesis is included in a variety of its functional effects. HGF levels were measured in 5 sessions of low-density lipoprotein (LDL) apheresis in 3 patients with severe hypercholesterolemia. Blood was collected at the start (T0) and at 1,000 ml (T1), 2,000 ml (T2), and 3,000 ml (T3) plasma treatments. During LDL apheresis, HGF levels increased from 1.59 +/- 0.78 (mean +/- SE, n = 5) ng/ml at T0 to 6.64 +/- 0.97 at T1, 6.28 +/- 0.97 at T2, and 5.20 +/- 0.94 at T3. In one apheresis session, HGF increased immediately at the 100 ml plasma treatment stage. HGF was adsorbed completely by a dextran-sulfate (DS) column. Despite the adsorption by the DS column, HGF in the patient blood increased to the levels with functional effects. The improvement of ischemic symptoms due to LDL apheresis may be related to the angiogenic activities of HGF.