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

Subnormal Serum Liver Enzyme Levels: A Review of Pathophysiology and Clinical Significance

Subnormal levels of liver enzymes, below the lower limit of normal on local laboratory reports, can be useful diagnostically. For instance, subnormal levels of aminotransferases can be observed in vitamin B6 deficiency and chronic kidney disease. Subnormal alkaline phosphatase levels may indicate the presence of hypophosphatasia, Wilson's disease, deficiencies of divalent ions, or malnutrition. Subnormal levels of gamma glutamyl transferase may be seen in cases of acute intrahepatic cholestasis, the use of certain medications, and in bone disease. Finally, subnormal levels of 5'-nucleotidase have been reported in lead poisoning and nonspherocytic hemolytic anemia. The aim of this review is to bring attention to the fact that subnormal levels of these enzymes should not be ignored as they may indicate pathological conditions and provide a means of early diagnosis.

Higher Serum Hepatocyte Growth Factor Concentration is Associated with Better Preservation of GFR in Hemodialysis Patients

BACKGROUND/AIMS

Hemodialysis induces an intravascular inflammatory reaction which may further deteriorate renal function. We studied changes of serum interleukin 6 (IL6) and hepatocyte growth factor (HGF) concentrations during dialysis sessions, and at 12 month intervals. The synthesis of these cytokines in arterial endothelial cells in the presence of serum obtained from dialyzed patients was studied. Changes of the inflammatory reaction during 12 months of treatment were correlated with GFR.

METHODS

The study was performed on a group of 30 uremic patients treated with hemodialysis. Serum samples were collected before the start of dialysis, 15 minutes, and 4 hours later, when the session was finished. Serum levels of IL6 and HGF were measured with ELISA, as was the effect of serum samples on the synthesis of these cytokines in arterial endothelial cells.

RESULTS

At baseline hemodialysis induced an increase of serum IL6 (+10%) and HGF (+164%) levels at the end of the session. After 12 months of treatment predialysis serum IL 6 level was increased as compared to the beginning of the study (+22%), but no change in serum HGF level was observed. At that time the dialysis-induced rise of serum IL6 level was stronger than at the start (+18%), but the observed effect for HGF was weaker (+116%). An inverse correlation was observed between the dialysis-induced increase of HGF level and decrease of GFR after 12 months of study. The same relation was seen for HGF synthesis in the endothelium, but opposite for IL6 synthesis in the endothelium.

CONCLUSIONS

We found that a higher HGF serum level during hemodialysis treatment is associated with a slower loss of residual renal function.

Diagnostic Dilemmas in Hepatitis C Virus Infection for Hemodialysis Patients

BACKGROUND

Hepatitis C virus (HCV) is a leading cause of chronic hepatitis in dialysis patients. The diagnosis of HCV infection in these patients is predominantly based on laboratory tests because of the specificity of the clinical course of the disease.

AIM

The present prospective study aimed at determining very accurately the prevalence rate of HCV infection in patients on dialysis by simultaneously testing them for anti-HCV and for HCV RNA levels.

MATERIALS AND METHODS

For the present cross-sectional longitudinal study we recruited and followed up 93 patients from St George University Hospital Hemodialysis Unit between July 2013 and December 2014. All patients were tested for anti-HCV and HCV RNA. The anti-HCV negative patients were tested for anti-HCV and HCV RNA at least twice at intervals of 6 months or more (up to 12 months). Anti-HCV antibodies were identified using a third generation ELISA assay. Commercial kits for real-time polymerase chain reaction (RT-PCR) were used to detect HCV RNA in the plasma and mononuclear cells. Aminotransferase and gammaglutamyl transpeptidase levels were studied to find if liver inflammation was present.

RESULTS

The total seroprevalence in 68 patients was 20.6% (14). Of these, 10 patients were viremic (HCV RNA+/anti-HCV+), and 4 patients (5.9%) had discordant results (anti-HCV+/HCV RNA-). Acute hepatitis was detected in one patient. Duration of dialysis in HCV viremic patients was longer than that in aviremic patients (p=0.005).

CONCLUSIONS

The present study suggests that HCV infection in dialysis patients can be diagnosed more accurately if these patients are tested using two diagnostic methods - a serological test and a biomolecular assay. Further studies with larger sample size may prove the feasibility of such approach for all dialysis patients in this country.

Potential Hepatoprotective Role of Galectin-3 during HCV Infection in End-Stage Renal Disease Patients

Hepatitis C virus infection (HCV), one of the greatest causes of liver disease, is a frequent complication in patients with end-stage renal disease (ESRD) on dialysis. ESRD is defined as decreased glomerular filtration and also accompanied by impaired function of the immune system. Galectin-3 is a β-galactoside-binding lectin, involved in various biological processes including pathogenesis of chronic renal disease. The aim of our study was to estimate disease severity in ESRD HCV⁺ patients and analyze the serum concentrations of IL-1β, IL-4, IL-23, and IL-6; anti-HCV antibodies; and galectin-3. Also, we attempted to determine potential correlation between galectin-3 level and parameters of disease severity ALT and AST. Our results showed decreased levels of ALT and AST (p = 0.00), demonstrating less liver destruction in ESRD HCV⁺ patients in comparison to HCV⁺ patients. Increased levels of IL-6 (p = 0.03) implicate a hepatoprotective role of IL-6 in these patients. Also, level of galectin-3 (p = 0.00) in the serum of ESRD HCV⁺ patients was higher than that of HCV⁺ patients. This alteration was accompanied with negative correlation between galectin-3 and AST and ALT, respectively (p = 0.029; p = 0.033). The presence of increased systemic levels of IL-6 and Gal-3 in ESRD HCV⁺ patients may be an attempt to counteract or limit ongoing proinflammatory processes and to downregulate chronic inflammation, suggesting the new aspects of HCV infection in ESRD patients.

Hepatitis C virus infection in maintenance hemodialysis patients: recommendations for diagnostics and treatment

Hepatitis C virus (HCV) infection is highly prevalent among patients treated with maintenance hemodialysis and is an important cause of morbidity and mortality. It is necessary to determine the HCV genotype and the viral load to monitor the clinical and laboratory features and to establish an optimal antiviral treatment strategy. Antiviral treatments are presented with a standard interferon-based regimen and new direct-acting antiviral agents. The advent of direct-acting antivirals has improved the efficacy and safety of HCV treatment for most patients, even in difficult-to-treat populations such as patients on hemodialysis. HCV treatment with direct-acting antivirals in hemodialysis patients is highly effective, with viral eradication rates similar to those seen in patients without chronic kidney disease and with acceptable adverse event profiles.

Hepatitis C virus infection and chronic kidney disease: Time for reappraisal

Hepatitis C virus (HCV) infection is associated with tremendous morbidity and mortality due to liver complications. HCV infection is also associated with many extrahepatic manifestations including cardiovascular diseases, glucose metabolism impairment, cryoglobulinemia vasculitis, B cell non-Hodgkin lymphoma and chronic kidney disease (CKD). Many studies have shown a strong association between HCV and CKD, by reporting (i) an increased prevalence of HCV infection in patients on haemodialysis, (ii) an increased incidence of CKD and proteinuria in HCV-infected patients, and (iii) the development of membranoproliferative glomerulonephritis secondary to HCV-induced cryoglobulinemia vasculitis. HCV seropositivity is found to be associated with an increased relative risk for all-cause and cardiovascular mortality in the dialysis population. HCV seropositivity is linked to lower patient and graft survival after kidney transplantation. Such poor HCV-associated prognosis should have encouraged clinicians to treat HCV in CKD patients. However, due to frequent side effects and the poor efficacy of interferon-based treatments, very few HCV dialysis patients have received HCV medications until now. The emergence of new direct acting, interferon-free antiviral treatment, leading to HCV cure in most cases with a satisfactory safety profile, will shortly modify the management of HCV infection in CKD patients. In patients with a glomerular filtration rate (GFR) >30ml/min, the choice of DAA is not restricted. In those with a GFR <30 and >15ml/min, only paritaprevir/ritonavir/ombitasvir/dasabuvir or a grazoprevir plus elbasvir regimen are approved. In patients with end stage renal disease (GFR <15ml/min or dialysis), current data only allows for the use of a grazoprevir plus elbasvir combination. No doubt these data will be modified in the future with the advent of new studies including larger cohorts of HCV patients with renal impairment.

Hepatocyte growth factor (HGF) and hemodialysis: physiopathology and clinical implications

Hepatocyte growth factor (HGF) is a pleiotropic cytokine which exerts a variety of effects on several cells, being involved in the regulation of many biological processes, such as inflammation, tissue repair, morphogenesis, angiogenesis, tumour propagation, immunomodulation of viral infections and cardio-metabolic activities. Patients undergoing regular hemodialysis (HD) present elevated levels of HGF, mainly due to the leukocyte activation associated with HD treatment. High HGF levels might account for specific clinical features of HD patients, i.e. mild liver damage in course of HCV-infection and high cardiovascular risk profile. Moreover, in patients with acute kidney injury, the induction of HGF may represent a crucial step to promote renal recovery, which can have important prognostic consequences in the short and long-term. In this review we discuss the mechanisms underlying HGF production in HD patients, the role of HGF in this particular patient population and the potential clinical implications derived from the study of HGF in HD patients.

Liver Support With Albumin Dialysis Reduces Hepatitis C Virus Viremia and Facilitates Antiviral Treatment of Severe Hepatitis C Virus Recurrence After Liver Transplantation

Patients with severe hepatitis C virus (HCV) recurrence after liver transplantation (LT) present an ominous prognosis, rarely achieving sustained virological response (SVR). Dialysis procedures may transiently decrease the HCV viral load, but the effect of albumin dialysis is currently unknown. Here, we evaluated the impact of albumin dialysis using the Molecular Adsorbent Recirculating System (MARS) used as a co-adjuvant antiviral treatment for severe HCV recurrence after LT. Thirteen patients (11 males, median age 48 years) with fibrosing cholestatic hepatitis or METAVIR fibrosis score ≥ F3 with severe portal hypertension underwent three consecutive MARS sessions. Antiviral therapy was initiated in 11 patients within 24 h after the MARS sessions. A contemporary cohort of seven patients who did not follow the MARS protocol is shown for comparison. MARS treatment resulted in consistent decreases of viral load from 7.59 log10 IU/mL [6.15-8.90] to 6.79 log10 IU/mL [5.18-7.84] (P = 0.003) as well as in decreases of serum bilirubin, gamma-glutamyl transpeptidase, alanine aminotransferase and aspartate aminotransferase (all P < 0.05). The overall rate of SVR was 0% in the Control group and 54.6% in patients initiating antiviral therapy within 24 h after MARS. Survival at 1 and 3 years was, respectively, 93% and 70% in patients undergoing MARS, compared with 29% and 14% in the Control group (P = 0.001). No major adverse events related to MARS treatment were observed. In conclusion, the use of MARS may facilitate the achievement of SVR and improve the prognosis of patients with severe HCV-recurrence after LT by reducing viral load and improving liver function prior to antiviral therapy.

The reduction of serum aminotransferase levels is proportional to the decline of the glomerular filtration rate in patients with chronic kidney disease

OBJECTIVE

This study sought to determine the serum aminotransferase levels of patients with predialysis chronic kidney disease and establish their relationships with serum creatinine levels and glomerular filtration rate.

METHODS

Patients with chronic kidney disease were evaluated between September 2011 and May 2012. Aminotransferase and creatinine serum levels were measured using an automated kinetic method, and glomerular filtration rates were estimated using the Cockroft-Gault and Modification of Diet in Renal Disease formulas to classify patients into chronic kidney disease stages.

RESULTS

Exactly 142 patients were evaluated (mean age: 64±16 years). The mean creatinine serum level and glomerular filtration rate were 3.3±1.2 mg/dL and 29.1±13 mL/min/1.73 m2, respectively. Patients were distributed according to their chronic kidney disease stages as follows: 3 (2.1%) patients were Stage 2; 54 (38%) were Stage 3; 70 (49.3%) were Stage 4; and 15 (10.5%) were Stage 5. The mean aspartate aminotransferase and alanine aminotransferase serum levels showed a reduction in proportion to the increase in creatinine levels (p=0.001 and p=0.05, respectively) and the decrease in glomerular filtration rate (p=0.007 and p=0.028, respectively). Alanine aminotransferase and aspartate aminotransferase serum levels tended to be higher among patients classified as stage 2 or 3 compared with those classified as stage 4 or 5 (p=0.08 and p=0.06, respectively).

CONCLUSIONS

The aspartate aminotransferase and alanine aminotransferase serum levels of patients with predialysis chronic kidney disease decreased in proportion to the progression of the disease; they were negatively correlated with creatinine levels and directly correlated with glomerular filtration rate.

Hepatitis C in hemodialysis patients

Despite reduction of hepatitis C prevalence after recognition of the virus and testing of blood products, hemodialysis (HD) patients still comprise a high risk group. The natural history of hepatitis C virus (HCV) infection in dialysis is not fully understood while the clinical outcome differs from that of the general population. HD patients show a milder liver disease with lower aminotransferase and viral levels depicted by milder histological features on liver biopsy. Furthermore, the “silent” clinical course is consistent with a slower disease progression and a lower frequency of cirrhosis and hepatocellular carcinoma. Potential explanations for the “beneficial” impact of uremia and hemodialysis on chronic HCV infection are impaired immunosurveillance leading to a less aggressive host response to the virus and intradialytic release of “hepatoprotective” cytokines such as interferon (IFN)-α and hepatocyte growth factor. However, chronic hepatitis C is associated with a higher liver disease related cardiovascular and all-cause mortality of HD patients. Therapy is indicated in selected patients groups including younger patients with low comorbidity burden and especially renal transplant candidates, preferably after performance of a liver biopsy. According to current recommendations, choice of treatment is IFN or pegylated interferon with a reported sustained viral response at 30%-40% and a withdrawal rate ranging from 17% to 30%. New data regarding combination therapy with low doses of ribavirin which provide higher standard variable rates and good safety results, offer another therapeutic option. The new protease inhibitors may be the future for HCV infected HD patients, though data are still lacking.

Hepatitis C virus infection in end-stage renal disease and kidney transplantation

Liver disease secondary to chronic hepatitis C virus (HCV) infection is an important cause of morbidity and mortality in patients with end-stage renal disease (ESRD) on renal replacement therapy and after kidney transplantation (KT). Hemodialytic treatment (HD) for ESRD constitutes a risk factor for bloodborne infections because of prolonged vascular access and the potential for exposure to infected patients and contaminated equipment. Evaluation of HCV-positive/ESRD and HCV-positive/KT patients is warranted to determine the stage of disease and the appropriateness of antiviral therapy, despite such treatment is challenging especially due to tolerability issues. Antiviral treatment with interferon (IFN) is contraindicated after transplantation due to the risk of rejection, and therefore, treatment is recommended before KT. Newer treatment strategies of direct-acting antiviral agents in combination are revolutionizing HCV therapy, as a result of encouraging outcomes streaming from recent studies which report increased sustained viral response, low or no resistance, and good safety profiles, including preservation of renal function. KT has been demonstrated to yield better outcomes with respect to remaining on HD although survival after KT is penalized by the presence of HCV infection with respect to HCV-negative transplant recipients. Therefore, an appropriate, comprehensive, easily applicable set of clinical practice management guidelines is necessary in both ESRD and KT patients with HCV infection and HCV-related liver disease.

Recent advances on hepatitis C virus in dialysis population

Hepatitis C virus (HCV) infection remains common among patients undergoing regular dialysis and good evidence supports the detrimental role of HCV on survival in patients undergoing maintenance dialysis. According to an updated meta-analysis of clinical studies (n=15; 195,370 unique patients on maintenance dialysis), the summary estimate for adjusted relative risk (all-cause mortality) with anti-HCV across the published studies was 1.32 with a 95% Confidence Intervals of 1.24; 1.42, homogeneity assumption was not rejected. Various mechanisms support the excess death risk of HCV-infected patients on regular dialysis, in addition to liver disease-related mortality. The adjusted relative risk for cardiovascular mortality among HCV-infected patients on regular dialysis was 1.26 (95% Confidence Intervals, 1.10; 1.45); the increased cardiovascular mortality in anti-HCV positive patients has been associated in part to malnutrition and chronic inflammation. The current standard of care for HCV in dialysis population is combined antiviral therapy (pegylated interferon plus ribavirin) with a rate of viral response of around 60%. Triple therapy with telaprevir proved to be effective and safe in dialysis patients with HCV but only anecdotal evidence exists. Antiviral treatment of HCV-infected patients on maintenance dialysis could lead to cure the liver damage and the extrahepatic complications. The future availability of all-oral interferon/ribavirin free regimens for antiviral treatment of HCV will help nephrologists to improve survival in this high-risk group.

Histological features of chronic hepatitis C in haemodialysis patients

BACKGROUND & AIMS

HCV infection in haemodialysis (HD) patients is still a matter of investigation. The aim of this study was to determine the histology of chronic hepatitis C (CHC) in HCV-infected HD patients within the context of a comparative analysis including non-uraemic patients with CHC. The relative importance of virological, demographic and clinical parameters on disease manifestation was examined.

METHODS

Sixty-one consecutive liver biopsies from HD patients and 326 from non-uraemic patients with chronic HCV infection were comparatively evaluated.

RESULTS

Haemodialysis patients with CHC were older than control subjects (P = 0.031), showing a similar HCV genotype distribution (P = 0.328) and lower viral load (P = 0.001). CHC in HD patients was significantly milder according to stage (P = 0.033), grade and its parameters (periportal activity, portal inflammation and lobular activity) (P < 0.001). The frequency of lymphoid aggregates (10.2% vs. 50%, P < 0.001), bile duct lesions (1.7% vs. 22.1%, P < 0.001) and extent of steatosis (P = 0.022) in HD group was significantly reduced. Multivariate analysis showed that non-uraemic patients had 2.3 times higher risk of developing steatosis independently of genotype distribution and age. In HD group, genotype 3, longer HD duration and age at infection were significantly associated with steatosis, while older age at infection correlated with advanced fibrosis.

CONCLUSIONS

Chronic hepatitis C in HD patients is usually very mild, losing its diagnostic histological features while patient's age and age at infection retain their prognostic significance. The weak inflammatory response, probably because of immunocompromised status and low viral load, may present a beneficial factor in the natural course of the disease.

Liver enzymes serum levels in patients with chronic kidney disease on hemodialysis: a comprehensive review

We reviewed the literature regarding the serum levels of the enzymes aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transferase in patients with chronic kidney disease on hemodialysis with and without viral hepatitis. Original articles published up to January 2013 on adult patients with chronic kidney disease on hemodialysis were selected. These articles contained the words "transaminases" "aspartate aminotransferase" "alanine aminotransferase" "gamma glutamyl transferase," "liver enzymes", AND "dialysis" OR "hemodialysis". A total of 823 articles were retrieved. After applying the inclusion and exclusion criteria, 49 articles were selected. The patients with chronic kidney disease on hemodialysis had reduced serum levels of aminotransferases due to hemodilution, lower pyridoxine levels, or elevated homocysteine levels. The chronic kidney disease patients on hemodialysis infected with the hepatitis C virus also had lower aminotransferase levels compared with the infected patients without chronic kidney disease. This reduction is in part due to decreased viremia caused by the dialysis method, the production of a hepatocyte growth factor and endogenous interferon-α, and lymphocyte activation, which decreases viral action on hepatocytes. Few studies were retrieved on gamma-glutamyl transferase serum levels; those found reported that there were no differences between the patients with or without chronic kidney disease. The serum aminotransferase levels were lower in the patients with chronic kidney disease on hemodialysis (with or without viral hepatitis) than in the patients with normal renal function; this reduction has a multifactorial origin.

Hepatitis C virus infection and dialysis: 2012 update

Hepatitis C virus infection is still common among dialysis patients, but the natural history of HCV in this group is not completely understood. Recent evidence has been accumulated showing that anti-HCV positive serologic status is significantly associated with lower survival in dialysis population; an increased risk of liver and cardiovascular disease-related mortality compared with anti-HCV negative subjects has been found. According to a novel meta-analysis (fourteen studies including 145,608 unique patients), the adjusted RR for liver disease-related death and cardiovascular mortality was 3.82 (95% CI, 1.92; 7.61) and 1.26 (95% CI, 1.10; 1.45), respectively. It has been suggested that the decision to treat HCV in patients with chronic kidney disease be based on the potential benefits and risks of therapy, including life expectancy, candidacy for kidney transplant, and co-morbidities. According to recent guidelines, the antiviral treatment of choice in HCV-infected patients on dialysis is mono-therapy but fresh data suggest the use of modern antiviral approaches (i.e., pegylated interferon plus ribavirin). The summary estimate for sustained viral response and drop-out rate was 56% (95% CI, 28-84) and 25% (95% CI, 10-40) in a pooled analysis including 151 dialysis patients on combination antiviral therapy (conventional or pegylated interferon plus ribavirin).

End-stage renal disease and African American race are independent predictors of mild liver fibrosis in patients with chronic hepatitis C infection

Recipients of haemodialysis for end-stage renal disease (ESRD) have a higher prevalence of hepatitis C virus (HCV) infection relative to the general US population. However, the natural course of HCV infection in patients with renal failure, including African Americans (AAs) and Caucasian Americans (CAs), is not well known. We compared the degree of liver inflammation and fibrosis in AA and CA patients with HCV infection, with and without ESRD. This was a cross-sectional study of 156 HCV patients with ESRD (130 AAs and 26 CAs) with a liver biopsy between 1992 and 2005. The control group consisted of 138 patients (50 AAs; 88 CAs) with HCV infections and a serum creatinine <1.5 mg/dL with a liver biopsy between 1995 and 1998. Specimens were graded for inflammation and fibrosis using Knodell histological activity index. Compared to patients without renal impairment, HCV patients with renal failure were older and more likely to be AA. Patients with renal impairment had lower mean serum transaminases, a higher mean serum alkaline phosphatase levels (all P < 0.0001) and less hepatic necro-inflammation (Knodell histological activity index -I, II and III; P < 0.05) and fibrosis (Knodell histological activity index -IV; P < 0.0001). There were no racial differences in serum liver chemistry and histology scores among patients with renal failure. In a multivariate analysis, younger age, ESRD, AA race and a lower serum alkaline phosphatase were associated with lower odds for advanced liver fibrosis. Thus, HCV patients with ESRD had a lower degree of hepatic inflammation and fibrosis compared to those without renal disease, independent of race.

Pegylated interferon monotherapy of chronic hepatitis C in dialysis patients: Meta-analysis of clinical trials

The efficacy and safety of pegylated interferon monotherapy in patients with chronic renal failure and chronic hepatitis C remains unclear, although a number of small clinical trials have been published addressing this issue. A systematic review of the literature with a meta-analysis of clinical trials was performed in order to assess efficacy and safety of initial pegylated interferon monotherapy in chronic renal failure patients with chronic hepatitis C. The primary outcome was sustained virological response (as a measure of efficacy); the secondary outcome was drop-out rate (as a measure of tolerability). The random effects model of Der Simonian and Laird was used, with heterogeneity and sensitivity analyses. Sixteen clinical trials (254 unique patients) were identified, five (31%) being controlled studies; the majority (15/16 = 94%) regarded patients on long-term dialysis. The summary estimate for sustained virological response and drop-out rate was 33% [95% Confidence Intervals (95%CI) 24-43] and 23% (95%CI, 14-33), respectively. The most frequent side-effects requiring interruption of treatment were haematological (18%) and gastrointestinal (14%). In the group of controlled clinical trials, the summary estimate for sustained viral response and drop-out rate was 38% (95% CI, 18-59), and 15% (95% CI, 3-26), respectively. The studies were heterogeneous with regard to sustained virological response and drop-out rate. Pegylated IFN does not provide an added benefit in terms of virological response in comparison with standard IFN monotherapy. Tolerance to pegylated-IFN monotherapy was unsatisfactory. Prospective trials are in progress to assess the optimal antiviral therapy for chronic hepatitis C in dialysis patients.

Effect of hemodialysis schedules and membranes on hepatocyte growth factor and hepatitis C virus RNA levels

Hemodialysis induces production of the hepatocyte growth factor (HGF) and decrease of serum hepatitis C virus (HCV) RNA in patients with HCV infection, but it is not known if the hemodialysis schedule or type of membrane affect both the HGF production and HCV viremia. The effects on both parameters of alternate-day intermittent hemodialysis and short-daily hemodialysis and high and low flux membranes were investigated in 41 patients treated by hemodialysis. Sixteen (39%) patients were anti-HCV positive and 11 (69%) had HCV RNA. Twenty-six patients were on alternate-day intermittent and 15 on short-daily hemodialysis. High flux membranes were used for 29 patients and low flux membranes for 12 patients. A decrease in HCV RNA was observed at the end of hemodialysis (8.6 x 10(5) +/- 1.1 x 10(6) IU/ml vs. 4.4 x 10(5) +/- 7.3 x 10(5) IU/ml, P = 0.003). The proportion of HCV RNA decrease was similar in patients dialyzed with both schedules and with both types of membranes. The HGF levels increased from 2,605.9 +/- 1,428.7 to >8,000 pg/ml at 15 min. At the end of the session, the HGF levels decreased to 5,106.7 +/- 2,533.9 pg/ml. The HGF levels at the start of the next session were similar to those at baseline (2,680.0 +/- 1,209.3 pg/ml). The increase and dynamics of the HGF levels were similar in patient's hemodialyzed with both schedules and with both types of membranes. These results suggest that changes in HCV RNA and HGF levels during hemodialysis are not influenced by the schedule or type of membrane used.

Health care-associated transmission of hepatitis B and C viruses in hemodialysis units

Liver disease is a significant cause of morbidity and mortality in patients receiving long-term dialysis. This article summarizes the most recent information on epidemiology, clinical significance, and management of infection by hepatitis B and C viruses in this population.

Factors associated with the progression of hepatic fibrosis in end-stage kidney disease patients with hepatitis C virus infection

BACKGROUND

Few studies have evaluated the histological aspects of hepatitis C virus (HCV) infection in hemodialysis patients and the factors related to the progression of hepatic fibrosis in this population have not been defined.

AIM

To evaluate the influence of host-related factors on the fibrosis progression in end-stage renal disease (ESRD) patients with HCV infection.

METHODS

HCV-infected ESRD patients who submitted to liver biopsy were included. The fibrosis stages were classified according to METAVIR scoring system. For the identification of factors associated with more advanced liver fibrosis, the patients were classified into two groups: group 1, absence of septal fibrosis (F0-1) and group 2, presence of septal fibrosis (F2-4). Groups 1 and 2 were compared regarding demographic, epidemiological, and laboratory variables and logistic regression analysis was used to identify the variables that were independently associated with the presence of septal fibrosis.

RESULTS

A total of 216 ESRD patients (63% men, 44+/-11 years) were included. In the histological analysis, the fibrosis stages were as follows: F0=36%, F1=41%, F2=12%, F3=7, and 4% had cirrhosis (F4). In the logistic regression model, the variables that were independently associated with the presence of septal fibrosis were duration of infection, estimated age at infection, coinfection with HBV and aspartate aminotransferase levels.

CONCLUSION

These findings support the importance of obtaining an adequate immune response to HBV vaccination and careful monitoring of liver disease in patients who become infected at an advanced age and/or those presenting elevated aspartate aminotransferase levels, as these are the main factors associated with the presence of septal fibrosis in ESRD patients.

Expression of Hepatocyte Growth Factor in Chronic Hepatitis: Effect of Hemodialysis

BACKGROUND AND AIMS

Elevated serum levels of hepatocyte growth factor (HGF) have been documented in patients on chronic hemodialysis (HD) and with chronic hepatitis (CH). The aim of this study was to determine the presence and density of HGF in liver tissue and the source of this factor in HD patient with CH.

MATERIAL AND METHODS

Seventy-five hepatic needle-biopsy specimens were investigated, 11 from CH patients (Group 1) and 44 from CH patients on HD (Group 2), plus 20 liver biopsies obtained from healthy individuals as controls (Group 3). All specimens were analyzed immunohistochemically with an HGF antibody.

RESULTS

Groups 1 (CH only) and 2 (CH + HD) had significantly (p < 0.05) more HGF-positive nonparenchymal cells than the control group. Also, specimens from CH-only patients (Group 1) had significantly (p < 0.05) more positive staining than those from CH patients on HD (Group 2). Groups 1 and 2 had similar results for grading of CH and fibrosis score. No association was found between the number of HGF-positive cells and necroinflammatory or fibrosis score.

CONCLUSIONS

The expression of HGF in liver tissue in CH patients on HD was much lower than in CH-only patients. The extrahepatic tissue might be the source of increased HGF serum levels in HD patients.

Impact of hemodialysis therapy on hepatitis C virus infection: a deeper insight

Hepatitis C Virus (HCV) infection remains prevalent in patients receiving regular dialysis all over the world. The adverse impact of anti-HCV serologic status on mortality in the dialysis population has been documented. Antiviral therapy for hepatitis C in chronic kidney disease (CKD) patients, including the dialysis population, is still unsatisfactory. Several findings support a different course of HCV in dialysis patients versus the non-uremic population. The HCV viral load appears lower in hemodialysis patients with HCV despite the immune compromise caused by chronic uremia; the histologic abnormalities seem milder, and a severe clinical course of chronic hepatitis C is unusual in most hemodialysis (HD) patients. It appears that the HD procedure per se can preserve patients from an aggressive course of HCV by reducing the viral load (HCV RNA). The mechanisms by which the HD procedure lowers HCV viremia remain largely speculative: the passage of viral particles into the dialysate, the trapping of the virus on the surface of the dialyzer membrane, and an indirect host-mediated mechanism have been cited. The latter hypothesis implicates the production of interferon-alpha, hepatocyte growth factor, or other cytokines provided with antiviral activities during the hemodialysis sessions. Clinical trials aimed at clarifying this issue are under way.

Scatter Factors in renal disease: Dr. Jeckyll and Mr. Hyde?

The Scatter Factors are two homologous proteins, named Scatter Factor/Hepatocyte Growth Factor and Macrophage Stimulating Protein. Their receptors are the products of two oncogenes, Met and Ron, respectively. The Scatter Factors induce movement, stimulate proliferation, regulate apoptosis and are morphogenic, i.e. operate an integrated program that seems tailored to drive organ development and to regenerate injured tissues. On the other hand, Scatter Factors may be responsible for pathologic tissue remodeling, infiltration of inflammatory cells, and tumor growth and diffusion. The review describes the involvement of Scatter Factors in renal disease, including acute renal failure, glomerulonephritis, chronic fibrosing nephropathies, dialysis, renal transplantation and renal tumors, and discusses the double-faced role of Scatter Factors, that play either a protective or a pathogenic role.

Serum alanine aminotransferase levels, hematocrit rate and body weight correlations before and after hemodialysis session

PURPOSE

To evaluate alanine aminotransferase levels before and after a hemodialysis session and to correlate these values with the hematocrit rate and weight loss during hemodialysis.

PATIENTS AND METHODS

The serum alanine aminotransferase levels, hematocrit rate and body weight were measured and correlated before and after a single hemodialysis session for 146 patients with chronic renal failure. An receiver operating characteristic (ROC) curve for the serum alanine aminotransferase levels collected before and after hemodialysis was plotted to identify hepatitis C virus-infected patients.

RESULTS

The mean weight loss of the 146 patients during hemodialysis was 5.3% (p < 0.001). The mean alanine aminotransferase levels before and after hemodialysis were 18.8 and 23.9 IU/, respectively, denoting a significant 28.1% increase. An equally significant increase of 16.4% in the hematocrit rate also occurred after hemodialysis. The weight loss was inversely correlated with the rise in both the alanine aminotransferase level (r = 0.3; p < 0.001) and hematocrit rate (r = 0.5; p < 0.001). A direct correlation was found between the rise in alanine aminotransferase levels and the hematocrit during the hemodialysis session (r = 0.4; p < 0.001). Based on the ROC curve, the upper limit of the normal alanine aminotransferase level should be reduced by 40% relative to the upper limit of normal if the blood samples are collected before the hemodialysis session or by 60% if blood samples are collected after the session.

CONCLUSION

In the present study, significant elevations in the serum alanine aminotransferase levels and hematocrit rates occurred in parallel to a reduction in body weight after the hemodialysis session. These findings suggest that one of the factors for low alanine aminotransferase levels prior to hemodialysis could be hemodilution in patients with chronic renal failure.

Hepatocyte growth factor/activin A/follistatin system activation during hemodialysis with different low molecular weight heparins

Hepatocyte growth factor (HGF), activin A (Act A), and follistatin (FS) compose an organotrophic system; interestingly it is modified by heparin. To understand if LMWHs (considered distinct drugs) have different clinical profiles regarding the above growth factors, we studied the effects of enoxaparin, nadroparin, and dalteparin on their plasma levels. Seventeen chronic HD patients completed this prospective, crossover trial. They were randomized into six groups: each patient was administered enoxaparin (effective dose of 0.75 mg/kg), nadroparin (70.4 IU/kg) and dalteparin (78.6 IU/kg) in three time periods of two months each. At the end of this period, the cytokine's plasma levels were measured by immunoassays at the start and at 10 min and 180 min of the HD procedure. At 10 min, we observed a striking increase in plasma HGF (32-fold), Act A (4-fold), and FS (53%), all p = 0.0003. The levels of HGF and Act A remained markedly elevated after 180 min (by 295% and 87%, respectively; both p < 0.002), while those of FS returned to baseline. There were no differences in cytokine profile comparing both their peak concentrations and the areas under the curve. Enoxaparin, dalteparin, and nadroparin are seemingly not different considering the release of HGF/Act A/FS during HD procedures; this may reflect their similar profile in other aspects. Moreover, the concentrations of HGF/Act A/FS are close to therapeutic ones, which may partly explain the mechanisms underlying some of the emerging extra-anticoagulant effects of LMWHs.

Kinetics of hepatitis B virus load and haemodialysis: a prospective study

The control of the spread of hepatitis B virus (HBV) infection within dialysis units has been an important goal in the management of patients on regular dialysis but infected patients continue to enter the dialysis system. It is evident that HBV viraemia in hepatitis B surface antigen (HBsAg)-positive patients on dialysis is low but it remains unclear whether haemodialysis per se can contribute to viral load reduction in such patients. HBV DNA was determined in 40 HBsAg-positive patients on maintenance haemodialysis immediately before and at the end of a 4-h haemodialysis session. The same measurements were repeated 48 and 72 h later. Twenty (50%) of 40 HBsAg-positive patients had detectable HBV DNA in serum. Detectable HBV DNA in serum was not predicted by demographic, clinical or biochemical parameters. HBV load decreased in the majority of patients after haemodialysis, although the difference was not significant (29 390 +/- 48 820 vs 23 862.8 +/- 4 350 copies/mL, NS). There was a strong relationship between mean HBV DNA levels before dialysis and absolute reduction of HBV DNA during haemodialysis sessions (r = 0.75, P = 0.0001). No difference occurred in the magnitude of change in HBV DNA titre when comparing cellulosic to synthetic membranes. Haemodialysis per se leads to a reduction in HBV load in HBsAg-chronic carriers on maintenance dialysis. This phenomenon could explain the low viral loads in these patients. Prospective studies are in progress to identify the mechanisms responsible for reduction in HBV load during haemodialysis.

HCV infection in haemodialysed patients: a role for serum IL-10 and TGF-beta1 in liver damage?

BACKGROUND

Hepatitis C virus (HCV) infection is often clinically silent in haemodialysed (HD) patients and their immune response may modulate liver damage in HCV infection. IL-10 and TGF-beta1 could play a role in this setting as, IL-10 down-regulates hepatic fibrosis, while TGF-beta1 is a pro-fibrotic cytokine.

AIM

To evaluate the role of IL-10 and TGF-beta1 in HD/HCV+ patients.

PATIENTS

71 HD/HCV+ patients (58 with normal [HD/HCV-N] and 13 with high serum transaminases [HD/HCV-H]), 40 non-uremic patients with chronic hepatitis C (HCV+), 56 HD anti-HCV- patients and 20 healthy volunteers (H).

METHODS

IL-10 and TGF-beta1 serum levels were assessed using ELISA tests. Liver histology was assessed by Ishak's score.

RESULTS

IL-10 serum levels were significantly higher in HD patients, both HCV+ (3.7+/-0.4 pg/ml; p<0.01) and HCV- (3.8+/-0.8 pg/ml; p<0.05) than in non-uremic HCV patients (2.3+/-0.4 pg/ml). Among the HD/HCV+ patients, IL-10 serum levels were similar in HD/HCV-N and in HD/HCV-H patients. Among the HD/HCV+ patients, IL-10 serum levels were similar in those with moderate histological damage compared to those with mild damage. TGF-beta1 serum levels were significantly lower in HD patients, both HCV+ (4.6+/-0.9 ng/ml) and HCV- (6.0+/-0.9 ng/ml) than in non-uremic HCV+ patients (8.1+/-1.1 ng/ml; p<0.001 and p<0.01, respectively), but similar to the values found in H (5.3+/-0.9 ng/ml; p=n.s.). No correlation was seen between IL-10 and TGF-beta1 serum levels in any of the groups considered.

CONCLUSIONS

Patients on haemodialysis treatment to have high levels of IL-10, which remain high even when patients are anti-HCV+, whereas the opposite is true of TGF-beta1. The cytokine pattern observed in HD patients is compatible with the hypothesis explaining the relatively benign evolution of HCV-related liver disease in HD patients, and has a pathophysiological role.

Hepatitis C is less aggressive in hemodialysis patients than in nonuremic patients

BACKGROUND AND OBJECTIVES

The severity of liver disease among hepatitis C patients on hemodialysis is controversial. The aim of this study was to compare the clinical, biochemical, and liver histologic characteristics of hepatitis C virus (HCV) in hemodialysis patients and in those with normal renal function.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A case-control study was carried out with 36 HCV patients on hemodialysis and 37 HCV patients with normal renal function matched for gender, age at infection, and estimated time of infection.

RESULTS

HCV patients on hemodialysis had lower levels of alanine aminotransferase and lower viral load. Hepatic fibrosis was significantly higher in the patients with normal renal function (73%) than in hemodialysis patients (47.2%, P < 0.025); the same was observed for inflammatory activity (control group 59.5% versus hemodialysis patients 27.7%, P = 0.003). In addition, the risk of tissue inflammation was four times lower in hemodialysis patients (odds ratio = 0.23, P < 0.004), and severe inflammatory activity on biopsy was the only independent risk factor for fibrosis (P < 0.001).

CONCLUSIONS

The lower biochemical and inflammatory activities observed in hemodialysis patients suggest that hemodialysis and uremia may have a protective role against progression of the disease caused by HCV.

Hepatitis C infection in patients with chronic kidney disease

The management of hepatitis C virus (HCV)-infected patients with chronic kidney disease (CKD) is complex and represents a particular concern since numerous issues, such as antiviral therapy in dialysis patients and post renal transplant, and prevention of HCV spread within dialysis units, remain unresolved. An enormous body of literature has been published on HCV in the CKD population; however, clinical evidence on important issues is mostly based on uncontrolled clinical trials or retrospective surveys. The aim of this paper is to provide a systematic review of the literature. Responses to the critical issues have been developed by a consensus of experts, endorsed by the Italian Association for the Study of the Liver (AISF) and some clinical recommendations have been added.

Hepatitis C in hemodialysis patients: current global magnitude, natural history, diagnostic difficulties, and preventive measures

Hepatitis C virus (HCV) infection is a significant cause of morbidity and mortality in hemodialysis (HD) patients. The reported prevalence of HCV among the HD population has varied greatly from 1.9 to 84.6% in different countries in recent years. The length of time on HD is generally believed to be associated with HCV acquisition in HD subjects. Nevertheless, several recent reports failed to recognize any significant role of blood transfusion. Although there are some considerations about the accuracy of serologic testing in detecting HCV in HD patients, the accumulated data in this review suggest the false-negativity rate to be not more than 1.66% (153/9,220). Therefore, substituting virologic for serologic testing in the routine diagnosis of HCV infection in HD patients seems unreasonable. Several phylogenetic analyzes of viral isolates suggested nosocomial patient-to-patient transmission of HCV among HD patients for which the main potential source is believed to be contaminated hands and articles. However, isolation of HCV-infected HD patients and use of dedicated machines are currently unjustified while strict adherence to universal precautions seems to be enough to control disease spread in HD units. The present article is an update on epidemiological and clinical features of HCV in HD population.

Interferon monotherapy of chronic hepatitis C in dialysis patients: meta-analysis of clinical trials

The efficacy of monotherapy with interferon (IFN) (conventional or pegylated IFN) in dialysis patients with chronic hepatitis C remains unclear, although a number of clinical trials have been published addressing this issue. The aim of the study was to evaluate the efficacy and safety of monotherapy by conventional or pegylated IFN in dialysis patients with chronic hepatitis C by performing a systematic review of the literature with a meta-analysis of clinical trials. The primary outcome was sustained virological response (SVR; as a measure of efficacy), and the secondary outcome was drop-out rate (as a measure of tolerability). We used the random-effects model of Der Simonian and Laird, with heterogeneity and sensitivity analyses. We identified 28 clinical trials (645 unique patients), of which six (21.4%) had a controlled design. In the group of trials based on conventional IFN, the summary estimate for SVR and drop-out rate was 39% [95% confidence interval (CI) 32-46] and 19% (95% CI 13-26) respectively. The summary estimate for SVR rate in patients with the hepatitis C virus genotype 1 was 33% (95% CI 19-47). In the subset of trials using pegylated IFN, the summary estimate for SVR and drop-out rate was 31% (95% CI 7-55) and 27% (95% CI 1-52) respectively. The most frequent side-effects requiring interruption of treatment were flu-like symptoms, and gastrointestinal and haematological changes. A relationship between age and drop-out rate was found, even if no statistical significance was reached (P = 0.064). The studies were heterogeneous with regard to SVR and drop-out rate. No publication bias was observed. One-third of dialysis patients with chronic hepatitis C were successfully treated with conventional or pegylated IFN monotherapy. Preliminary evidence does not support additional benefit due to monotherapy with pegylated IFN on the viral response in the chronic kidney disease (CKD) population. Tolerance to IFN monotherapy was unsatisfactory, particularly to pegylated IFN. The optimal antiviral treatment of chronic hepatitis C in dialysis populations is currently under active investigation.

Attenuation of glycerol-induced acute kidney injury by previous partial hepatectomy: role of hepatocyte growth factor/c-met axis in tubular protection

BACKGROUND/AIMS

Previous partial hepatectomy (HPTX) can attenuate glycerol-induced acute kidney injury (Gly-AKI). The aim of this study was to explore the pathophysiological mechanisms and the role of hepatocyte growth factor (HGF) in kidney protection.

METHODS

Rats were subjected to HPTX 24 h before glycerol administration. Renal function, acute tubular necrosis, apoptosis, leukocyte infiltration, and the expression of HGF, c-met, monocyte chemoattractant protein-1, interleukin-1beta, and heme oxygenase-1 were evaluated 24 h after glycerol injection. The regenerative response was analyzed from 6 to 72 h after glycerol injection (BrdU incorporation). In a separate series of experiments, Gly-AKI+HPTX rats were treated with anti-HGF antibody.

RESULTS

Gly-AKI+HPTX rats showed an increased expression of renal HGF and c-met as well as an improved creatinine clearance and reduced acute tubular necrosis and apoptosis, cytokine expression, and leukocyte infiltration. The regenerative response was less intense 24 and 72 h after glycerol administration in this group. The anti-HGF treatment disclosed an important role of HGF in the reduction of tubular injury, particularly apoptosis. Overexpression of heme oxygenase-1 was observed in Gly-AKI+HPTX rats, but was not associated with HPTX-induced renal protection.

CONCLUSION

We conclude that Gly-AKI+HPTX rats have a reduced susceptibility to renal injury instead of an increased regenerative response and that endogenous HGF overexpression is responsible for suppression of tubular apoptosis.