Metabolic disorders induced by PNPLA3 and TM6SF2 gene variants affect chronic kidney disease in patients infected with non-genotype 3 hepatitis C virus

BACKGROUND

Patients with chronic hepatitis C virus (HCV) infections differ in their risk for metabolic disorders and chronic kidney disease (CKD). The aim of this study was to investigate the effect of metabolic disorders induced by genetic factors on CKD in HCV-infected patients.

METHODS

Patients with chronic non-genotype 3 HCV infection with or without CKD were examined. PNPLA3 and TM6SF2 variants were determined using high-throughput sequencing. The relationships of variants and different combinations with metabolic disorders were analyzed in CKD patients. Univariate and multivariate analyses were used to identify factors associated with CKD.

RESULTS

There were 1022 patients with chronic HCV infection, 226 with CKD and 796 without CKD. The CKD group had more severe metabolic disorders, and also had higher prevalences of liver steatosis, the PNPLA3 rs738409 non-CC genotype, and the TM6SF2 rs58542926 CC genotype (all P < 0.05). Relative to patients with the PNPLA3 rs738409 CC genotype, patients with the non-CC genotype had a significantly decreased eGFR and a greater prevalence of advanced CKD (CKD G4-5). Patients with the TM6SF2 rs58542926 CC genotype had a lower eGFR and a higher prevalence of CKD G4-5 than those with the non-CC genotype. Multivariable analysis indicated that multiple metabolic abnormalities, including liver steatosis and the PNPLA3 rs738409 C > G variant, increased the risk of CKD, but the TM6SF2 rs58542926 C > T variant decreased the risk of CKD.

CONCLUSION

Specific PNPLA3 rs738409 and TM6SF2 rs58542926 variants are independent risk factors for CKD in patients with chronic HCV infections and are associated with the severity of renal injury.

Viral Glomerulopathy

Background

The association between viral infections and glomerular diseases, commonly known as "viral glomerulopathies," has been described in various clinical scenarios for decades. Despite advancements in diagnostic tools, it remains challenging to establish a causative link fully.

Summary

Data from mouse models have substantiated clinical observations and implicate direct viral infection in the pathogenesis of viral glomerulopathy, particularly in human immunodeficiency virus-associated nephropathy. In addition to the traditional concept of direct viral effects on kidneys, other factors such as APOL1 risk alleles can further modify the clinical outcomes or presentations of different viral glomerulopathies. Newly developed antiviral drugs are now applicable to a wider range of patients with lower kidney function and fewer side effects.

Key Message

Efforts focusing on vaccines and antiviral treatments have significantly reduced the incidence of viral glomerulopathies. However, the most recent pandemic caused by severe acute respiratory syndrome coronavirus 2 infection complicated by COVID-associated nephropathy illustrates our susceptibility to novel viruses. Ongoing research is pivotal to deciphering the mechanisms behind viral glomerulopathies and discovering therapeutics in a collaborative approach.

Innate immune suppression by SARS-CoV-2 mRNA vaccinations: The role of G-quadruplexes, exosomes, and MicroRNAs

The mRNA SARS-CoV-2 vaccines were brought to market in response to the public health crises of Covid-19. The utilization of mRNA vaccines in the context of infectious disease has no precedent. The many alterations in the vaccine mRNA hide the mRNA from cellular defenses and promote a longer biological half-life and high production of spike protein. However, the immune response to the vaccine is very different from that to a SARS-CoV-2 infection. In this paper, we present evidence that vaccination induces a profound impairment in type I interferon signaling, which has diverse adverse consequences to human health. Immune cells that have taken up the vaccine nanoparticles release into circulation large numbers of exosomes containing spike protein along with critical microRNAs that induce a signaling response in recipient cells at distant sites. We also identify potential profound disturbances in regulatory control of protein synthesis and cancer surveillance. These disturbances potentially have a causal link to neurodegenerative disease, myocarditis, immune thrombocytopenia, Bell's palsy, liver disease, impaired adaptive immunity, impaired DNA damage response and tumorigenesis. We show evidence from the VAERS database supporting our hypothesis. We believe a comprehensive risk/benefit assessment of the mRNA vaccines questions them as positive contributors to public health.

Progress in hepatitis C virus management in chronic kidney disease

PURPOSE OF REVIEW

The current review highlights advances in the use of direct-acting antiviral (DAA) agents in the treatment of hepatitis C virus (HCV) in chronic kidney disease (CKD) stages G4-5, end-stage renal disease, and kidney transplantation. The use of DAA to facilitate kidney transplantation of HCV negative recipients with kidneys from HCV-infected donors and in the management of HCV-related cryoglobulinemia are also reviewed.

RECENT FINDINGS

DAA treatment results in rates of viral clearance (sustained virological response or SVR) of 90-100% in all studied CKD populations, comparable to SVR rates in the general population. DAA treatment allows safe and effective transplantation of HCV viremic kidneys into uninfected recipients.

SUMMARY

The high SVR results achieved with DAA allow successful treatment of previously under-treated CKD populations, and encouraged innovative interventions such as the use of HCV-infected donor kidneys to uninfected kidney transplant recipients.

Impact of DAA-Based Regimens on HCV-Related Extra-Hepatic Damage: A Narrative Review

Two-third of patients with chronic hepatitis C show extrahepatic manifestations due to HCV infection of B lymphocytes, such as mixed cryoglobulinemia and non-Hodgkin B-cell lymphoma, or develop a chronic inflammatory status that may favor the development of adverse cardiovascular events, kidney diseases or metabolic abnormalities.DAAs treatments induce HCV eradication in 95% of treated patients, which also improves the clinical course of extrahepatic manifestations, but with some limitations. After HCV eradication a good compensation of T2DM has been observed, but doubts persist about the possibility of obtaining a stable reduction in fasting glucose and HbA1c levels.Chronic HCV infection is associated with low total and LDL cholesterol serum levels, which however increase significantly after HCV elimination, possibly due to the disruption of HCV/lipid metabolism interaction. Despite this adverse effect, HCV eradication exerts a favorable action on cardiovascular system, possibly by eliminating numerous other harmful effects exerted by HCV on this system.DAA treatment is also indicated for the treatment of patients with mixed cryoglobulinemia syndrome, since HCV eradication results in symptom reduction and, in particular, is effective in cryoglobulinemic vasculitis. Furthermore, HCV eradication exerts a favorable action on HCV-related lymphoproliferative disorders, with frequent remission or reduction of clinical manifestations.There is also evidence that HCV clearance may improve impaired renal functions, but same conflicting data persist on the effect of some DAAs on eGFR.

Ribavirin as a beneficial treatment option for hepatitis C virusassociated glomerular disease

The management of hepatitis C virus (HCV)-induced glomerular disease remains unsatisfactory despite novel advances in antiviral and immunosuppressive therapy. Recent evidence highlighted the role of ribavirin, a drug provided with immunomodulatory properties, in the treatment of glomerular diseases associated with chronic HCV. We administered low-dose ribavirin (200 mg/day or 200 mg twice a week or 200 mg thrice weekly) in a prospective fashion to a group of patients with HCV-associated glomerular disease (n = 7). Ribavirin monotherapy was given in most (n = 6) patients and was accompanied by erythropoietin therapy in all. The primary endpoint was reduction of 24-h proteinuria after treatment ended; the secondary end-points were decrease in serum creatinine and amelioration of urinary abnormalities. We collected data on on-treatment adverse events (AEs), serious AEs, and laboratory abnormalities. Many patients (n = 6) had inactive HCV infection as they had shown HCV RNA clearance from serum after antiviral therapy with direct-acting antivirals. Some patients (n = 4) had membranoproliferative glomerulo- nephritis, the diagnosis being confirmed by kidney histology in three cases; others (n = 2) received diagnosis of diabetic glomerulosclerosis, confirmed in one by kidney biopsy. We observed consistent reduction of 24-h proteinuria in two individuals after ribavirin therapy; another patient reported disappearance of microscopic hematuria. We found severe AE (hemolytic anemia) in three patients which required discontinuation of ribavirin treatment in two patients, one required hospitalization. Other AEs were cutaneous rash (n = 1), dyspepsia (n = 1), and fatigue (n = 1). Low-dose ribavirin was able to give consistent reduction of 24-h proteinuria in two patients; tolerance to ribavirin was unsatisfactory. We need further studies aimed to expand our knowledge on ribavirin therapy of HCV-associated glomerular disease. The low incidence of the disease hampers the conduction of clinical trials on this aim.

Direct acting antiviral HCV treatment does not influence renal function

HCV infection is associated with chronic kidney disease due to several mechanisms. Patients treated with interferon-based regimens demonstrate improved renal function and reduced incidence of chronic kidney disease. There is scarce evidence on the effect of direct acting antiviral regimens (DAAs) on renal function.We evaluated serial measures of renal function in a cohort of HCV-infected participants following completion of DAA-based treatment regimens.Measures of glomerular filtration rate (GFR) were estimated by the CKD-EPI equation. Data was recorded at end of treatment, and at 6-12 months, 12-24 months, and greater than 24 months following treatment completion. Group-based trajectory modeling was used to determine distinct GFR trajectories. Predictors of group membership were determined by multinomial regression analysis.Six trajectories were identified. One trajectory comprising 27% of the cohort demonstrated declining renal function and the others demonstrated no change in renal function over time. Baseline GFR did not predict SVR. Diabetes was associated with lower post-treatment GFR but patients with diabetes did not demonstrate a decrease in GFR over the period of evaluation. Cirrhosis and SVR were not significant predictors of GFR or GFR trajectory.There is no clinically relevant change in renal function among the majority of HCV-infected patients following completion of DAA-based treatments. Renal function does not influence the efficacy of DAA-based regimens. No consistent effect of DAA treatment and/or SVR on renal function was observed over a 2-year period following treatment completion.

Membranous nephropathy associated with viral infection

Background

Membranous nephropathy (MN) can be associated with hepatitis infection and less commonly with human immunodeficiency virus (HIV) infection. The significance of anti-phospholipase A2 receptor (PLA2R) and anti-thrombospondin type 1 domain-containing 7A (THSD7A) antibodies in this setting is unclear.

Methods

We describe the clinical, histopathological and outcome data of 19 patients with MN and hepatitis B virus (HBV), hepatitis C virus (HCV) or HIV infection identified through our renal biopsy database and the association with anti-PLA2R antibodies and anti-THSD7A antibodies.

Results

The cohort consisted of 19 patients, 8 male and 11 female, with a median age of 42 years (range 23–74). HBV infection was found in six cases, HCV in four and HIV in nine (two HIV patients had HBV co-infection and one HCV co-infection). PLA2R staining on biopsy was positive in 10/19 patients: 4 with HBV-MN, 3 with HCV-MN and 3 with HIV-MN and circulating anti-PLA2R antibodies were detected in 7/10 cases. THSD7A staining on biopsy was positive in three PLA2R-negative cases, one with HBV-MN and two with HIV-MN. Mean proteinuria was higher in the PLA2R-positive group and the median urinary protein:creatinine ratio (uPCR) was 963 mg/mmol (range 22–2406) compared with the PLA2R-negative group [median uPCR 548 mg/mmol (range 65–1898); P = 0.18 Mann–Whitney]. Spontaneous remission occurred in 6/19 patients and after-treatment remission occurred in 7/11 patients. Renal function was preserved in all but two patients who required haemodialysis 2 and 11 years from diagnosis.

Conclusions

We describe a cohort of patients with MN associated with viral infection, including rare cases of HIV-MN with PLA2R and THSD7A positivity. The mechanism of coincidental or viral-related MN needs to be investigated further.

The Effect of Viral Clearance Achieved by Direct-Acting Antiviral Agents on Hepatitis C Virus Positive Patients with Type 2 Diabetes Mellitus: A Word of Caution after the Initial Enthusiasm

The causal link between chronic hepatitis C and glycometabolic alterations has been confirmed by much biochemical, clinical, and epidemiological research work, but what is still controversial is the long-term clinical impact of sustained virologic response (SVR) achieved by direct-acting antiviral agents (DAAs) on patients with type 2 diabetes mellitus (DM). The aim of this paper is to summarize the biochemical and clinical consequences to DM of DAA-based therapy for hepatitis C virus (HCV) infection. An electronic search of Embase, PubMed, MEDLINE, Ovid, and the Cochrane Database of Systematic Reviews was conducted for publications assessing whether clearance of HCV achieved by interferon (IFN)-free antiviral therapy determines significant changes in glycometabolic control and clinical outcomes of diabetic patients. A beneficial effect of SVR obtained by DAA therapy on DM prevention and the short-term outcome of glycometabolic alterations are acknowledged by most of the studies. Whether this effect is maintained over the long term with a significant clinical impact on diabetic and liver disease is still a matter of debate.

Sustained virological response from interferon-based hepatitis C regimens is associated with reduced risk of extrahepatic manifestations

BACKGROUND & AIMS

HCV infection is associated with several extrahepatic manifestations (EHMs). We evaluated the impact of sustained virological response (SVR) on the risk of 7 EHMs that contribute to the burden of extrahepatic disease: type 2 diabetes mellitus, chronic kidney disease or end-stage renal disease, stroke, ischemic heart disease, major adverse cardiac events, mood and anxiety disorders, and rheumatoid arthritis.

METHODS

A longitudinal cohort study was conducted using data from the British Columbia Hepatitis Testers Cohort, which included ~1.3 million individuals screened for HCV. We identified all HCV-infected individuals who were treated with interferon-based therapies between 1999 and 2014. SVR was defined as a negative HCV RNA test ≥24 weeks post-treatment or after end-of-treatment, if unavailable. We computed adjusted subdistribution hazard ratios (asHR) for the effect of SVR on each EHM using competing risk proportional hazard models. Subgroup analyses by birth cohort, sex, injection drug exposure and genotype were also performed.

RESULTS

Overall, 10,264 HCV-infected individuals were treated with interferon, of whom 6,023 (59%) achieved SVR. Compared to those that failed treatment, EHM risk was significantly reduced among patients with SVR for type 2 diabetes mellitus (asHR 0.65; 95%CI 0.55-0.77), chronic kidney disease or end-stage renal disease (asHR 0.53; 95% CI 0.43-0.65), ischemic or hemorrhagic stroke (asHR 0.73; 95%CI 0.49-1.09), and mood and anxiety disorders (asHR 0.82; 95%CI 0.71-0.95), but not for ischemic heart disease (asHR 1.23; 95%CI 1.03-1.47), major adverse cardiac events (asHR 0.93; 95%CI 0.79-1.11) or rheumatoid arthritis (asHR 1.09; 95% CI 0.73-1.64).

CONCLUSIONS

SVR was associated with a reduction in the risk of several EHMs. Increased uptake of antiviral therapy may reduce the growing burden of EHMs in this population.

LAY SUMMARY

We estimated the rates of chronic comorbidities other than liver disease between those who were cured and those who failed treatment for hepatitis C virus (HCV) infection. Our findings showed that the rates of these non-liver diseases were largely reduced for those who were cured with interferon-based treatments. Early HCV treatments could provide many benefits in the prevention of various HCV complications beyond liver disease.

Evolution of renal function under direct-acting antivirals treatment for chronic hepatitis C: A real-world experience

Renal toxicity of direct-acting antivirals (DAAs) in chronic hepatitis C (CHC) patients has not been well-characterized. The aim of this study was to assess renal safety of DAAs in an Asian CHC patient cohort. Data from CHC patients (n = 1536) treated with DAAs were used in this retrospective study. Serial estimated glomerular filtration rate (eGFR) at pretreatment (1-year prior to treatment), baseline, end of treatment (EOT), and 12 weeks after treatment (SVR₁₂ ) was evaluated. While a significant decrease in eGFR from baseline to EOT (84.8 → 81.8 mL/min/1.73 m² , P < .001) was observed; subsequently, a slight rise at SVR₁₂ (84.3 mL/min/1.73 m² ) was also evident. Changes in eGFR after DAA treatment were similar to those seen in PrOD, DCV/ASV and GZP/EBV regimens, except in the SOF-based regimen wherein eGFR remained unchanged from EOT to SVR₁₂ , especially in liver transplant recipients. Multivariate analysis revealed that age >65 years (OR = 1.862, P = .011), baseline eGFR ≥ 60 mL/min/1.73 m² (OR = 2.684, P = .023), and liver transplant (OR = 3.894, P = .001) were independent risk factors for deteriorating renal function. In conclusion, DAA treatment led to a significant decline in eGFR at EOT but was followed by a slight rise at 12 weeks after treatment. A similar trend was observed with PrOD, DCV/ASV and GZP/EBV, but not in SOF-based regimens. As age >65 years, baseline eGFR ≥ 60 mL/min/1.73 m² and liver transplantation are significant risk factors for deterioration in renal function, we strongly advice close monitoring of renal function in these populations.

Rituximab treatment for immune-complex-mediated membranoproliferative glomerulonephritis

Immune-complex-mediated membranoproliferative glomerulonephritis (MPGN) is a new concept that refers to MPGN with immunoglobulin and C3 deposition in the kidney based on immunofluorescence examination. It is associated with pathological autoantibodies production. Rituximab, as an immunosuppressive agent, can eliminate B cells selectively. We reported a case that a patient with immune-complex-mediated MPGN and HCV infection, but no cryoglobulinemia, responded well to the treatment of low-dosage of rituximab and steroids. His proteinuria decreased remarkably with the serum creatinine and liver function remaining stable within 1 year. His favorable outcome suggests that low-dosage of rituximab in conjunction with steroids is an effective and safe treatment choice for immune-complex-mediated MPGN.

Anti-hepatitis C virus therapy in chronic kidney disease patients improves long-term renal and patient survivals

BACKGROUND

Hepatitis C virus (HCV) infection is a documented risk factor for chronic kidney disease (CKD) and progression to end-stage renal disease (ESRD). However, to date there are no reports on the long-term hard endpoints (ESRD and death) of anti-HCV therapy [interferon-based therapy (IBT) or new direct-acting antivirals] in CKD patients. Direct-acting antivirals are not available in Taiwan's single-payer national health insurance database currently released for research. Therefore, we hypothesized that a retrospective analysis of the long-term outcomes of IBT in CKD patients will serve as a proxy for direct-acting antivirals to increase our understanding of progression to ESRD following HCV infection.

AIM

To evaluate the long-term outcomes (ESRD and death) of anti-HCV therapy, especially IBT, in HCV-infected patients with stage 1-5 CKD.

METHODS

We analyzed 93894 Taiwanese adults diagnosed with CKD and without HBV infection. Of these, 4.9% were infected with HCV. Of the 4582 HCV-infected CKD patients, 482 (10.5%) received IBT (treated cohort). They were matched 1:4 with 1928 untreated HCV-infected CKD patients (untreated cohort) by propensity scores and year, which further matched 1:2 by propensity scores with 3856 CKD patients without HCV infection (uninfected cohort). All participants were followed until the occurrence of ESRD, death, or the end of 2012. The association between HCV infection, IBT use, and risks of ESRD and death was analyzed using competing risk analysis.

RESULTS

Taking the uninfected cohort as a reference, the adjusted hazard ratios for ESRD, after adjusting for competing mortality, were 0.34 (0.14-0.84, P = 0.019) and 1.28 (1.03-1.60, P = 0.029) in the treated and untreated cohorts, respectively. The treated cohort had a 29% (0.54-0.92, P = 0.011) decrease in mortality compared to the untreated cohort, in which the mortality was 31% (1.18-1.45, P < 0.001) higher than in the uninfected cohort. The reduced risks of ESRD (0.14, 0.03-0.58, P = 0.007) and death (0.57, 0.41-0.79, P = 0.001) were greatest in HCV-infected CKD patients who received at least 4 mo of IBT, which accounted for 74% of the treated cohort.

CONCLUSION

Adequate anti-HCV therapy in CKD patients improves long-term renal and patient survival.

Association of Hepatitis C and B Virus Infection with CKD and Impact of Hepatitis C Treatment on CKD

Hepatitis C virus (HCV) infection greatly increases the risk of nephropathy. In this observational study, we aimed to explore the relationship between viral hepatitis infection and chronic kidney disease (CKD), identify risk factors, and determine the effect of antiviral treatment on CKD in Chinese patients with chronic HCV infection. A total of 2,435 study subjects were enrolled and divided into four groups: the HCV infection, HBV infection, HBV and HCV co-infection, and uninfected control groups. Of these, 207 patients with chronic hepatitis C (CHC) were given standard dual therapy [subcutaneous injection of recombinant interferon (IFN)-α2b and oral ribavirin (RBV)] for 48 weeks. We found that the prevalence of CKD gradually increased with age in all groups and was significantly increased in patients 60 years or older. Multivariate logistic regression analyses showed that persistent HCV infection was significantly associated with CKD [odds ratio (OR), 1.33; 95% confidence interval (CI), 1.06–1.66; P = 0.013], whereas there was no significant link between CKD and spontaneous HCV clearance (OR, 1.23; 95% CI, 0.79–1.90; P = 0.364), HBV infection (OR, 0.73; 95% CI, 0.44–1.19; P = 0.201), or HBV/HCV co-infection (OR, 1.40; 95% CI, 0.81–2.40; P = 0.234). Notably, after anti-HCV therapy, the serum creatinine concentration was significantly decreased (76.0, 75.5–79.4 μmol/L) from the pretreatment level (95.0, 93.0–97.2 μmol/L), both in patients who showed an end of treatment virological response (ETVR) and those who did not (P < 0.001). Also, in both the ETVR and non-ETVR groups, the percentages of patients with an estimated glomerular filtration rate (eGFR) ≥90 ml/min/1.73 m² increased significantly (P < 0.001), whereas the percentages of those with an eGFR <60 ml/min/1.73 m² significantly decreased (P < 0.001). In conclusion, persistent HCV infection was independently associated with CKD, and antiviral treatment with IFN plus RBV can improve renal function and reverse CKD in HCV-infected patients.

Impact of sustained virologic response on chronic kidney disease progression in hepatitis C

AIM

To determine how sustained virological response at 12 wk (SVR12) with direct acting antivirals (DAAs) for the treatment of hepatitis C virus (HCV) infection affects chronic kidney disease (CKD) progression.

METHODS

A retrospective analysis was performed in patients aged ≥ 18 years treated for HCV with DAAs at the VA Greater Los Angeles Healthcare System from 2014-2016. The treatment group was compared to patients with HCV from 2011-2013 who did not undergo HCV treatment, prior to the introduction of DAAs; the control group was matched to the study group in terms of age, gender, and ethnicity. Analysis of variance and co-variance was performed to compare means between SVR12 subgroups adjusting for co-variates.

RESULTS

Five hundred and twenty-three patients were evaluated. When comparing the rate of change in estimated glomerular filtration rate (eGFR) one-year after HCV treatment to one-year before treatment, patients who achieved SVR12 had a decline in GFR of 3.1 mL/min ± 0.75 mL/min per 1.73 m² compared to a decline in eGFR of 11.0 mL/min ± 2.81 mL/min per 1.73 m² in patients who did not achieve SVR12 (P = 0.002). There were no significant clinical differences between patients who achieved SVR12 compared to those who did not in terms of cirrhosis, treatment course, treatment experience, CKD stage prior to treatment, diuretic use or other co-morbidities. The decline in eGFR in those with untreated HCV over 2 years was 2.8 mL/min ± 1.0 mL/min per 1.73 m², which was not significantly different from the eGFR decline noted in HCV-treated patients who achieved SVR12 (P = 0.43).

CONCLUSION

Patients who achieve SVR12 have a lesser decline in renal function, but viral eradication in itself may not be associated improvement in renal disease progression.

Membranous nephropathy associated with hepatitis C virus infection treated with corticosteroids and Ledipasvir-Sofosbuvir: a case report and review of literature

Background

Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults. As many clinical cases have reported, it may be associated with hepatitis C virus (HCV) infection. Antiviral therapy can be various.

Case summary

We report a case of patient with chronic HCV infection and MN, who presented with was proteinuria. He was treated with ledipasvir and sofosbuvir (Harvoni; Gilead Sciences, Foster City, CA) and was found to be virus-free.

Conclusion

We have reported this case to provide insight into whether Ledipasvir-Sofosbuvir should be administered for HCV-related glomerulonephritis.

[Renewed 2015 Clinical Practice Guidelines for Management of Hepatitis C by Korean Association for the Study of the Liver; What Has Been Changed? - Indications for Treatment]

The landscape of treatment for HCV infection has evolved substantially with the advent of highly effective direct-acting antiviral agents (DAA). The Korean Association for the Study of the Liver updated guideline for managemnt of hepatitis C in accordance with the introduction of DAA into practice in late 2015. Due to high effectiveness and few side effects of DAA, indications for treatment has been widened to include patients who had been contraindicated for the combination treatment of peginterferon-α and ribavirin, i.e. decompensated cirrhosis and pre- and post-liver transplant setting. As succeesul treatment of HCV can reduce complications of cirrhosis, development of hepatocelluar carcinoma and liver-related mortality, and improve extrahepatic manifestions, all HCV-infected patients with no contraindication should be considered for treatment. Considering the risk for morbidity and mortality and benefit of treatment, patients with advanced fibrosis ≥F3 including compensated and decompensated cirrhosis, those in the pre- and post-tranplasnt setting, and those with severe extrahepatic manifestations including HCV-related mixed cryoglobulinemia and glomerulonephritis should be given priority for treatment.

Impact of hepatitis C virus therapy on metabolism and public health

Chronic hepatitis C virus (HCV) is associated with insulin resistance (IR) and leads to type 2 diabetes mellitus (T2DM) and hepatic steatosis in many patients. These metabolic complications of HCV have been shown to accelerate the progression of fibrosis to cirrhosis and increase the risk of hepatocellular carcinoma. The metabolic syndrome is a common disorder that also includes IR, T2DM and hepatic steatosis. Approximately 20%-30% of patients with chronic HCV also have co-existent metabolic syndrome. The cause of steatosis in patients with the features of both the metabolic syndrome and chronic HCV is sometime difficult to determine. Patients with metabolic syndrome and chronic HCV are also at risk of developing renal, cardiovascular and cerebrovascular disease. Recent data suggest that HCV is an independent risk factor for renal, coronary and cerebral vascular disease, and may increase mortality associated with these disorders. The treatment of HCV can now result in a sustained virological response and cure nearly all patients with chronic HCV. The eradication of HCV reduces the risk of developing IR and T2DM, improves IR and 2TDM, reduces the risk of developing chronic kidney disease, end-stage renal disease, acute cardiac syndrome and stroke in patients with 2TDM. Thus, treatment of chronic HCV can provide a significant public health benefit, but only if all patients with chronic HCV are identified and universally treated.

An Evidence-Based Approach to Conducting Systematic Reviews on CKD

With the growing need to integrate best evidence to inform clinical care, systematic reviews have continued to flourish. Although this type of review is integral to the synthesis of evidence-based information, systematic reviews are often conducted omitting well-established processes that ensure the validity and replicability of the study; elements of which are integral based on standards developed by the Cochrane Collaboration and the National Academy of Medicine. This review article will share best practices associated with conducting systematic reviews on the topic of CKD using an 8-step process and an evidence-based approach to retrieving and abstracting data. Optimal methods for conducting systematic review searching will be described, including development of appropriate search strategies and utilization of varied resources including databases, grey literature, primary journals, and handsearching. Processes and tools to improve research teams' coordination and efficiency, including integration of systematic review protocols and sophisticated software to streamline data management, will be investigated. In addition to recommended strategies for surveying and synthesizing CKD literature, techniques for maneuvering the complex field of Nephrology will also be explored.

A Case of Cryoglobulinemic Membranoproliferative Glomerulonephritis Induced by Hepatitis C Virus

A 61-year-old man with bilateral purpura of the lower limbs and subsequent edema, was hospitalization after renal dysfunction developed. The presence of hepatitis C virus (HCV) RNA and cryoglobulin and the finding of membranoproliferative glomerulonephritis on renal biopsy led to a diagnosis of HCV-related glomerulonephritis due to cryoglobulinemia. Because of the pre-existence of nephrotic syndrome and the continuously increasing serum level of creatinine, treatment with cryofiltration, interferon, and steroids was started. After 5 cryofiltration sessions, the cryocrit level had decreased to 1% and the levels of serum creatinine and proteinuria had also decreased. However, 3 weeks after the start of treatment, nephrotic syndrome developed again and was accompanied by lower-extremity mononeuropathy and renal dysfunction. Thereafter, the patient showed disorientation, an affective disorder, and delirium, and his condition gradually deteriorated. Radiological examination of the head and examination of the cerebrospinal fluid showed no abnormalities. Despite the withdrawal of the interferon therapy and the reduction of the steroid dose, the patient's conditions remained unchanged, and the level of consciousness deteriorated. Although cryofiltration had beneficial effects and plasma exchange was continuously performed, the patient died on the 74th hospital day. Because of the significant changes due to ventilatory support and hemorrhage associated with disseminated intravascular coagulation, the autopsy findings did not allow us to definitively determine whether the symptoms had been caused by the HCV-related membranoproliferative glomerulonephritis or the interferon therapy or both. We have reported this case to provide insight into whether interferon therapy should be administered for HCV-related membranoproliferative glomerulonephritis with marked neurological symptoms due to cryoglobulinemia.

Treatment of type 2 diabetes mellitus by viral eradication in chronic hepatitis C: Myth or reality?

Chronic hepatitis C is a systemic disease inducing metabolic alterations leading to extrahepatic consequences. In particular, hepatitis C virus (HCV) infection seems to increase the risk of incident type 2 diabetes mellitus in predisposed individuals, independently of liver disease stage. The mechanisms through which hepatitis C induces T2DM involve direct viral effects, insulin resistance, pro-inflammatory cytokines and other immune-mediated processes. Many studies have reported the clinical consequences of type 2 diabetes mellitus on hepatitis C outcome, but very few studies have addressed the issue of microangiopathic complications among patients with hepatitis C only, who develop type 2 diabetes mellitus. Moreover, clinical trials in HCV-positive patients have reported improvement in glucose metabolism after antiviral treatment; recent studies have suggested that this metabolic amelioration might have a clinical impact on type 2 diabetes mellitus-related complications. These observations raise the question as to whether the HCV eradication may also have an impact on the future morbidity and mortality due to type 2 diabetes mellitus. The scope of this review is to summarise the current evidence linking successful antiviral treatment and the prevention of type 2 diabetes mellitus and its complications in hepatitis C-infected patients.

Association between antiviral treatment and extrahepatic outcomes in patients with hepatitis C virus infection

OBJECTIVE

To elucidate the association between antiviral therapy and extrahepatic outcomes in individuals infected with HCV.

METHODS

This nationwide cohort study screened 293,480 Taiwanese residents with HCV infection and excluded those with substantial comorbidity. A total of 12,384 eligible patients who had received pegylated interferon plus ribavirin between 1 October 2003 and 31 December 2010 were enrolled in the treated cohort; they were matched 1 : 2 with 24,768 untreated controls in the propensity score and post-diagnosis treatment-free period. The incidences of end-stage renal disease (ESRD), acute coronary syndrome (ACS), ischaemic stroke and catastrophic autoimmune diseases were calculated after adjustment for competing mortality.

RESULTS

The treated and untreated cohorts were followed up for a mean (±SD) duration of 3.3 (±2.5) and 3.2 (±2.4) years, respectively, until 31 December 2011. The calculated 8-year cumulative incidences of ESRD, ACS, ischaemic stroke and autoimmune catastrophes between treated and untreated patients were 0.15% vs. 1.32% (p<0.001), 2.21% vs. 2.96% (p=0.027), 1.31% vs. 1.76% (p=0.001) and 0.57% vs. 0.49% (p=0.816), respectively. Multivariate-adjusted Cox regression revealed that antiviral treatment was associated with lower risks of ESRD (HR 0.15; 95% CI 0.07 to 0.31; p<0.001), ACS (HR 0.77; 95% CI 0.62 to 0.97; p=0.026) and ischaemic stroke (HR 0.62; 95% CI 0.46 to 0.83; p=0.001), but unrelated to autoimmune catastrophes. These favourable associations were invalid in incompletely treated patients with duration <16 weeks.

CONCLUSIONS

Antiviral treatment for HCV is associated with improved renal and circulatory outcomes, but unrelated to catastrophic autoimmune diseases.

Hepatitis C and kidney disease: An overview and approach to management

Hepatitis C infection and chronic kidney disease are major health burden worldwide. Hepatitis C infection is associated with a wide range of extra-hepatic manifestations in various organs including the kidneys. A strong association between hepatitis C and chronic kidney disease has come to light. Hemodialysis in supporting the end stage renal disease patients unfortunately carries a risk for hepatitis C infection. Despite much improvement in the care of this group of patients, the prevalence of hepatitis C infection in hemodialysis patients is still higher than the general population. Hepatitis C infection has a negative effect on the survival of hemodialysis and renal transplant patients. Treatment of hepatitis C in end stage renal disease patients using conventional or pegylated interferon with or without ribavirin remains a clinical challenge with low response rate, high dropout rate due to poor tolerability and many unmet needs. The approval of new direct acting antiviral agents for hepatitis C may dramatically change the treatment approach in hepatitis C infected patients with mild to moderate renal impairment. However it remains to be confirmed if the newer Hepatitis C therapies are safe in individuals with severe renal impairment. This review article discusses the relationship between hepatitis C and chronic kidney disease, describe the various types of renal diseases associated with hepatitis C and the newer as well as the existing treatments for hepatitis C in the context of this subpopulation of hepatitis C patients.

Hepatitis C virus associated glomerulopathies

Hepatitis C virus (HCV) infection is a systemic disorder which is often associated with a number of extrahepatic manifestations including glomerulopathies. Patients with HCV infection were found to have a higher risk of end-stage renal disease. HCV positivity has also been linked to lower graft and patient survivals after kidney transplantation. Various histological types of renal diseases are reported in association with HCV infection including membranoproliferative glomerulonephritis (MPGN), membranous nephropathy, focal segmental glomerulosclerosis, fibrillary glomerulonephritis, immunotactoid glomerulopathy, IgA nephropathy, renal thrombotic microangiopathy, vasculitic renal involvement and interstitial nephritis. The most common type of HCV associated glomerulopathy is type I MPGN associated with type II mixed cryoglobulinemia. Clinically, typical renal manifestations in HCV-infected patients include proteinuria, microscopic hematuria, hypertension, acute nephritis and nephrotic syndrome. Three approaches may be suggested for the treatment of HCV-associated glomerulopathies and cryoglobulinemic renal disease: (1) antiviral therapy to prevent the further direct damage of HCV on kidneys and synthesis of immune-complexes; (2) B-cell depletion therapy to prevent formation of immune-complexes and cryoglobulins; and (3) nonspecific immunosuppressive therapy targeting inflammatory cells to prevent the synthesis of immune-complexes and to treat cryoglobulin associated vasculitis. In patients with moderate proteinuria and stable renal functions, anti-HCV therapy is advised to be started as pegylated interferon-α plus ribavirin. However in patients with nephrotic-range proteinuria and/or progressive kidney injury and other serious extra-renal manifestations, immunosuppressive therapy with cyclophosphamide, rituximab, steroid pulses and plasmapheresis should be administrated.

Antiviral treatment for hepatitis C virus infection is associated with improved renal and cardiovascular outcomes in diabetic patients

Hepatitis C virus (HCV) infection is causally associated with insulin resistance and diabetes mellitus. This population-based cohort study aimed to investigate whether antiviral therapy for HCV infection was associated with improved clinical outcomes related to diabetes. From the Taiwan National Health Insurance Research Database, 2,267,270 Taiwanese residents diagnosed with diabetes mellitus were screened for eligibility. HCV infection was defined by a specific diagnosis code and measurement of serum antibody. After excluding patients with serious comorbidity, we enrolled a total of 1,411 eligible patients who received pegylated interferon plus ribavirin (treated cohort), and matched them 1:1 with 1,411 untreated controls by propensity scores (untreated cohort). We also matched the treated cohort 1:4 with 5,644 diabetic patients without HCV infection (uninfected cohort). Participants were followed up for the occurrence of endstage renal disease (ESRD), ischemic stroke, and acute coronary syndrome (ACS) after receiving antiviral treatment or the corresponding calendar date. From 2003 to 2011, the 8-year cumulative incidences of ESRD in the treated, untreated, and uninfected cohorts were 1.1% (95% confidence interval [CI], 0.3-2.0%), 9.3% (95% CI, 5.9-12.7%), and 3.3% (95% CI, 2.3-4.3%), respectively (P < 0.001); those of stroke were 3.1% (95% CI, 1.1-5.0%), 5.3% (95% CI, 3.0-7.5%), and 6.1% (95% CI, 4.8-7.4%), respectively (P = 0.01); and those for ACS were 4.1% (95% CI, 2.1-6.1%), 6.6% (95% CI, 3.7-9.5%), and 7.4% (95% CI, 5.9-9.0%), respectively (P = 0.05). As compared with the untreated cohort, antiviral treatment was associated with multivariate-adjusted hazard ratios of 0.16 (95% CI, 0.07-0.33%) for ESRD, 0.53 (95% CI, 0.30-0.93) for ischemic stroke, and 0.64 (95% CI, 0.39-1.06) for ACS.

CONCLUSION

Antiviral treatment for HCV infection is associated with improved renal and cardiovascular outcomes in diabetic patients.

Interleukin 28B gene polymorphisms in hepatitis C virus-related cryoglobulinemic vasculitis

OBJECTIVE

Single-nucleotide polymorphisms (SNP) in the interleukin 28B (IL-28B) gene region are strongly predictive of the response of infected patients to antiviral therapy for hepatitis C virus (HCV). We sought to determine the prevalence of SNP IL-28B rs12979860 C/C and non-C/C (C/T plus T/T) genotypes in HCV-related cryoglobulinemic vasculitis (CV), as compared with HCV-positive patients without CV. We also searched for their association with peculiar clinical manifestations of CV and potential influence on the complete response (virological, molecular, and immunological) to the therapy.

METHODS

The study cohort comprised 159 and 172 HCV-infected patients with and without CV, respectively, prospectively followed starting from 1990. SNP rs12979860 genotyping was performed by Taq-Man allelic discrimination. In 106 patients (66.6%) with CV, the profile of circulating B cell clonalities was determined as well. All patients with CV were treated with pegylated interferon-α/ribavirin-based antiviral therapy.

RESULTS

The T/T IL-28B genotype was more common in patients with CV than in those without (17% vs 8.1%, p = 0.02). In patients with CV, compared with non-C/C variants, the IL-28B C/C genotype was associated with a higher rate of complete response (52.6% vs 39.2%, p = 0.13), whereas a treatment response of 61.4% was demonstrated when solely virological response was considered (p = 0.008). A higher frequency of expanded B cell clonalities in the circulation (84.2% vs 55.9%; p = 0.005), kidney involvement (21% vs 2.9%; p = 0.003), and B cell non-Hodgkin lymphoma (17.5% vs 6.8%; p = 0.048), were also observed.

CONCLUSION

In HCV-positive patients with CV, the IL-28B C/C genotype is distinguished biologically by a higher frequency of restriction of B cell response and clinically by a higher risk of cryoglobulinemic nephropathy and B cell malignancies, while acting as an independent predictor of a sustained virological response to antiviral therapy. In addition, we found that IL-28B T/T variant was more prevalent in patients with CV than in those without.

Detection of viral antigens in renal tissue of glomerulonephritis patients without serological evidence of hepatitis B virus and hepatitis C virus infection

OBJECTIVES

Glomerulonephritis is an important extrahepatic manifestation of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. HBV and HCV infection may be occult, and they are often overlooked by both patients and doctors. The aim of this study was to assess the importance of HBV and HCV infection in glomerulonephritis patients with undetectable HBV surface antigen (HBsAg) and HCV antibody in serum.

METHODS

The HBsAg, the HBV core antigen (HBcAg), and the HCV antigen were detected using immunohistochemistry in frozen renal tissues of 500 glomerulonephritis patients without serological evidence of HBV and HCV infection. Electron microscopy was used to trace the virus particles, and clinicopathological features were also reviewed.

RESULTS

HBsAg or HBcAg was positive in nine out of 500 cases (9/500, 1.8%). Three cases were HBsAg-positive and another six cases were HBcAg-positive. The HCV antigen was found in eight cases (8/500, 1.6%). There was one case of HBV and HCV co-infection (1/500, 0.2%). Under electron microscopy, virus particles were found in the base membrane and cytoplasm of endotheliocytes in the glomerulus. The most common clinical manifestation was nephrotic syndrome (9/18), followed by nephritic syndrome (7/18). Membranous nephropathy was the most common pathological diagnosis (5/18), followed by mesangioproliferative glomerulonephritis (4/18) and IgA nephropathy (4/18).

CONCLUSIONS

Occult HBV and HCV infection might be implicated in HBV- or HCV-associated glomerulonephritis. More attention should be focused on the underlying cause.

Autoimmune manifestations in viral hepatitis

Infections by the viruses responsible for hepatitis B, C and D are accompanied by a number of immunopathological manifestations. A link between infection and autoimmunity is particularly well documented for the hepatitis C virus. Immunopathological manifestations range from production of autoantibodies to overt autoimmune disease, including thyroiditis and autoimmune hepatitis, and to immune-complex-mediated disorders, including cryoglobulinaemia, glomerulonephritis and vasculitis. Several of these manifestations improve with successful antiviral treatment, directly incriminating the virus in their pathogenesis. Mechanisms considered responsible for hepatitis virus-related immunopathology, including molecular mimicry, impairment of regulatory T cells and activation of B lymphocytes, will be examined in this review.