Detection of hepatitis B virus DNA and RNA in kidneys of HBV related glomerulonephritis

Hepatitis B virus-targeting sodium taurocholate cotransporting polypeptide mediates HBV infection and damage in human renal podocytes

Hepatitis B virus (HBV) may directly infect human podocytes (HPCs). However, the mechanism of direct infection is unclear. We found that HPCs express sodium taurocholate cotransporting polypeptide (NTCP), a specific receptor for HBV entry into hepatocytes. Thus, we investigated whether NTCP mediates HBV infection and damage in HPCs and further clarified the specific mechanism. We constructed shRNA-NTCP1,2, shRNA-NC, WT-NTCP, and MUT-NTCP and transfected them into HPCs. HPCs were infected with HBV, and HBV infection markers were detected by enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (RT-qPCR). The functional changes in HPCs were detected by Transwell migration and scratch assays, apoptosis was evaluated by flow cytometry (FCM), and podocytoskeletal proteins (nephrin, CD2AP, and synaptopodin) were determined by western blotting (WB). Compared with the control HPCs, HPCs infected with HBV showed increased levels of HBV infection markers and apoptosis along with decreased podocytoskeletal protein expressions, cell vitality, proliferation, and migration. Compared with the HPCs infected with HBV, the HPCs transfected with HBV + shRNA-NTCP, and HBV + MUT-NTCP showed decreased levels of HBV infection markers and apoptosis along with increased podocytoskeletal protein expressions, cell vitality, proliferation, and migration; the opposite effects were observed in the HPCs transfected with HBV + WT-NTCP. Overall, the changes to NTCP affected the susceptibility of HPCs to HBV and modulated HPC damage and repair. NTCP can mediate direct HBV infection and damage human podocytes, and the NTCP 157-165 locus is the main site of HBV entry. The findings provide a new target and theoretical basis for HBV-associated glomerulonephritis.

IMPORTANCE

This study identified for the first time that sodium taurocholate cotransporting polypeptide (NTCP) can mediate HBV direct infection and damage to human podocytes, and the NTCP157-165 locus is the main HBV entry site. The findings provide theoretical support for the pathogenesis of direct infection of HBV with kidney tissue. The findings provide a new target and theoretical basis for the treatment of HBV-related glomerulonephritis (HBV-GN). Blocking NTCP is a new target for the treatment of HBV-GN. We found that tacrolimus, a calcineurin inhibitor that blocks NTCP, can effectively treat HBV-GN. This study also provides a theoretical basis for the effective and safe treatment of immunosuppressant tacrolimus for HBV-GN.

Clinicopathologic features and long-term prognosis of hepatitis B virus-associated glomerulonephritis: a retrospective cohort study

BACKGROUND

Hepatitis B virus-associated glomerulonephritis is a common form of secondary glomerulonephritis in China. However, the clinicopathological features and long-term prognosis of Hepatitis B virus-associated Glomerulonephritis remain only partially known.

METHODS

Biopsy-proven Hepatitis B virus-associated Glomerulonephritis patients were enrolled between November 1994 and December 2013 at our center. The composite endpoints were doubling serum creatinine, end-stage renal disease, or death from renal disease during follow-up. The clinicopathological features and predictors of the long-term prognosis of Hepatitis B virus-associated Glomerulonephritis patients were explored.

RESULTS

The median age of the 259 Hepatitis B virus-associated Glomerulonephritis patients was 31.0 years (IQR 24.0-40.0), and 71.0% were males. Among the patients, 45.2% presented with nephrotic syndrome, and 45.9% presented with proteinuria combined with hematuria. The two most prevalent pathological patterns were IgA nephropathy (27.0%) and membranous nephropathy (27.0%). The mean follow-up period was 68.8 ± 46.9 months. The 3-, 5-, and 10-year clinical event-free survival rates were 93.4%, 85.2%, and 70.3%, respectively. Multivariable Cox regression analysis showed that hypertension (HR 2.580, 95% CI 1.351-4.927, P = 0.004), hyperuricemia (HR 2.101, 95% CI 1.116-3.954, P = 0.021), glomerulosclerosis (P = 0.001), and intrarenal arterial lesions (P = 0.041) were independent predictors of composite clinical event endpoint. Patients in the antiviral therapy group exhibited a significantly better prognosis compared to those who received no antiviral therapy (log-rank χ2 = 5.772, P = 0.016).

CONCLUSION

Hepatitis B virus-associated Glomerulonephritis has specific clinicopathologic features and should not be considered a benign disease in adults. Hypertension, hyperuricemia, glomerulosclerosis, and intrarenal arterial lesions were independent predictors of the long-term prognosis in Hepatitis B virus-associated Glomerulonephritis patients. Antiviral therapy could be effective in improving the long-term prognosis of Hepatitis B virus-associated Glomerulonephritis patients.

Comparison of kidney function decline between chronic hepatitis B patients with or without antiviral therapy

BACKGROUND AND AIMS

Kidney function can deteriorate in patients with chronic hepatitis B (CHB). We compared the risk of kidney function decline between untreated and treated CHB patients receiving antiviral therapy.

METHODS

This retrospective study included 1061 untreated CHB patients and 366 tenofovir alafenamide (TAF), 190 besifovir dipivoxil maleate (BSV), and 2029 entecavir (ETV) users. The primary outcome was kidney function decline, a ≥ one-stage increase in chronic kidney disease for ≥3 consecutive months.

RESULTS

The incidence and risk of kidney function decline were significantly higher in the 1:1 propensity score matched treated group (588 pairs) than in the untreated (2.7 per 1000 person-years [PYs] vs. 1.3 per 1000 PYs, adjusted hazard ratio [aHR] = 2.29, all p < 0.001). The matched TAF group (222 pairs) showed a similar risk for the primary outcome (aHR = 1.89, p = 0.107) despite a significantly higher incidence thereof, compared to the untreated (3.9 vs. 1.9 per 1000 PYs, p = 0.042). The matched BSV and untreated groups (107 pairs) showed no significant differences in the incidence and risk. However, ETV users (541 pairs) carried a significantly higher outcome incidence and risk than the matched untreated (3.6 vs. 1.1 per 1000 PYs, aHR = 1.05, all p < 0.001). Compared to each matched untreated group, changes in the estimated glomerular filtration rate over time were greater in the ETV group (p = 0.010), despite being similar in the TAF (p = 0.073) and BSV groups (p = 0.926).

CONCLUSIONS

Compared with untreated patients, TAF or BSV users showed similar risk, whereas ETV users showed a higher risk of kidney function decline.

Chronic hepatitis B virus infection increases the risk of upper urinary calculi

Background

Although hepatitis B virus (HBV) is a recognized risk factor for renal diseases, little is known about HBV infection in individuals with upper urinary calculi (UUC). We investigated the relationship between chronic HBV infection and UUC.

Methods

We retrospectively analysed data from 1399 patients who were discharged from the Department of Urology (2017–2018). The diagnosis of UUC was determined using urinary tract ultrasonography or computed tomography, and HBV infection was evaluated by a positive hepatitis B surface antigen (HBsAg) test. Data on patients with and without UUC and HBsAg-positive and HBsAg-negative patients were compared by univariate and multivariate analyses.

Results

Data on chronic HBV infection and UUC were available for 1062 patients, including 514 who presented with UUC and 548 who did not. Overall, 5.8% of total patients, 8.0% of UUC patients and 3.8% of non-UUC patients had chronic HBV infection. UUC patients (41/514) had a significantly higher prevalence of HBsAg positivity (OR 2.175; 95% CI 1.267–3.734; P = 0.004) than non-UUC patients (21/548). After stratifying by sex, the relative odds of HBsAg positivity were statistically significant in men (OR 2.156; 95% CI 1.162–4.003; P = 0.015) but not in women (OR 2.947; 95% CI 0.816–10.643; P = 0.099). The incidence of urinary pH > 6 and staghorn stones was significantly higher in HBsAg-positive UUC patients than in HBsAg-negative UUC patients.

Conclusion

This is the first study to demonstrate that chronic HBV infection is strongly associated with UUC, at least in men. The urinary pH > 6 and staghorn stones were more common in UUC patients with chronic HBV infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-022-01038-z.

Association of Chronic Hepatitis B Infection and Antiviral Treatment With the Development of the Extrahepatic Malignancies: A Nationwide Cohort Study

PURPOSE

Epidemiologic studies suggest that chronic hepatitis B (CHB) is a risk factor for various primary extrahepatic malignancies. Our aim was to evaluate the associations of CHB and nucleos(t)ide analog (NA) treatment with the risk of the development of extrahepatic malignancies.

PATIENTS AND METHODS

We conducted an 18-month landmark analysis using nationwide claims data from the National Health Insurance Service of South Korea. Patients newly diagnosed with CHB in 2012-2014 (n = 90,944) and matched-controls (n = 685,436) were included. Patients with CHB were further classified as the NA-treated (CHB+/NA+, n = 6,539) or the NA-untreated (CHB+/NA-, n = 84,405) group. Inverse probability of treatment weighting analysis was applied to balance the treatment groups. Time-varying Cox analysis was performed to evaluate time-varying effect of NA treatment. The primary outcome was the development of any primary extrahepatic malignancy. Development of intrahepatic malignancy and death were considered as competing events.

RESULTS

During the study period (median = 47.4 months), 30,413 patients (3.9%) developed any extrahepatic malignancy. The CHB+/NA- group had a higher overall risk of extrahepatic malignancy than the CHB+/NA+ group (adjusted subdistribution hazard ratio [aSHR] = 1.28; 95% CI, 1.12 to 1.45; P < .001) or controls (aSHR = 1.22; 95% CI, 1.18 to 1.26; P < .001). There was no difference in the risk of extrahepatic malignancy between the CHB+/NA+ group and the controls (CHB+/NA+ v control: aSHR = 0.96; 95% CI, 0.84 to 1.08; P = .48). In time-varying Cox analysis, the CHB+/NA- patients were associated with a higher risk of extrahepatic malignancy than the CHB+/NA+ patients (aSHR = 1.37; 95% CI, 1.23 to 1.52; P < .001).

CONCLUSION

Patients with CHB have an elevated risk of developing primary extrahepatic malignancy. Long-term NA treatment was associated with a lower risk of extrahepatic malignancy development among patients with CHB.

Metabolic Regulation of Hepatitis B Virus Infection in HBV-Transgenic Mice

Hepatitis B virus (HBV) infection is a worldwide health burden. Metabolomics analysis has revealed HBV-induced metabolism dysregulation in liver tissues and hepatocytes. However, as an infectious disease, the tissue-specific landscape of metabolic profiles of HBV infection remains unclear. To fill this gap, we applied untargeted nuclear magnetic resonance (NMR) metabolomic analysis of the heart, liver, spleen, lung, kidney, pancreas, and intestine (duodenum, jejunum, ileum) in HBV-transgenic mice and their wild-type littermates. Strikingly, we found systemic metabolic alterations induced by HBV in liver and extrahepatic organs. Significant changes in metabolites have been observed in most tissues of HBV-transgenic mice, except for ileum. The metabolic changes may provide novel therapeutic targets for the treatment of HBV infection. Moreover, tissue-specific metabolic profiles could speed up the study of HBV induced systemic metabolic reprogramming, which could help follow the progression of HBV infection and explain the underlying pathogenesis.

Acute kidney injury and hepatorenal syndrome in cirrhosis

Acute kidney injury (AKI) in cirrhosis, including hepatorenal syndrome (HRS), is a common and serious complication in cirrhotic patients, leading to significant morbidity and mortality. AKI is separated into two categories, non-HRS AKI and HRS-AKI. The most recent definition and diagnostic criteria of AKI in cirrhosis and HRS have helped diagnose and prognosticate the disease. The pathophysiology behind non-HRS-AKI and HRS is more complicated than once theorized and involves more processes than just splanchnic vasodilation. The common biomarkers clinicians use to assess kidney injury have significant limitations in cirrhosis patients; novel biomarkers being studied have shown promise but require further studies in clinical settings and animal models. The overall management of non-HRS AKI and HRS-AKI requires a systematic approach. Although pharmacological treatments have shown mortality benefit, the ideal HRS treatment option is liver transplantation with or without simultaneous kidney transplantation. Further research is required to optimize pharmacologic and nonpharmacologic approaches to treatment. This article reviews the current guidelines and recommendations of AKI in cirrhosis.

Hepatitis B Virus-Related Glomerulonephritis with Positive and Negative Serum HBsAg: Different Clinicopathologic Characteristics of Two Clinical Subtypes

INTRODUCTION

The clinicopathologic characteristics of Hepatitis B virus-associated glomerulonephritis (HBV-GN) patients with different serum HBsAg are not well known. This study aims to investigate the characteristics and treatments between HBV-GN patients with positive and negative serum HBsAg.

METHODS

A retrospective review of patients with renal biopsies in Guangdong Provincial People's Hospital from 2005 to 2018 was performed. Clinicopathological data, treatments and remission of proteinuria were collected and compared between HBsAg+ and HBsAg- group.

RESULTS

A total of 101 HBV-GN were recruited. Serum HBsAg+ and HBsAg- patients accounted for 62.4% and 37.6%, respectively. HBsAg+ group had poor kidney and liver functions. Pathological data showed the percentage of membranous nephropathy in HBsAg- group is significantly higher than that of HBsAg+ group (60.3% HBsAg+ vs 89.5% HBsAg-, P<0.05). Chronic renal tubular/interstitial injury was more prevalent in HBsAg+ group (16.9% HBsAg+ vs 2.6% HBsAg-, P<0.05). The deposition sites of immune complexes were significant different between the two groups. In addition, more HBsAg+ patients were given anti-HBV and less were given corticosteroid or immunosuppressants for treatment than that of HBsAg- patients. Percentages of clinical remission were increasing in both HBsAg+ and HBsAg- patients from 1, 3, 6 months to 1 year (18.75%, 45.2%, 67.8%, 82.4% vs 24.4%, 41.2%, 62.8%, 59.3%). The differences of remission betwen two groups were not significant (P>0.05).

CONCLUSION

The clinicopathological characteristics and treatments of HBV-GN with serum HBsAg+ and HBsAg- were distinct, which indicated that the pathogenesis might be different and specific treatments were needed for HBV-GN patients with different serum HBsAg.

Efficacy of entecavir in treating hepatitis B virus-associated membranous nephropathy

OBJECTIVE

hepatitis B virus-associated membranous nephropathy (HBV-MN) is the most common pathological type of hepatitis B virus-associated glomerulonephritis. This study evaluated the efficacy of entecavir antiviral therapy for HBV-MN patients due to the intolerable side effects of interferon-alpha and high incidence rate of drug-resistance in lamivudine therapy.

METHOD

thirty-two patients with HBV-MN were identified by biopsy and treated with entecavir for 52 weeks. These patients were followed up to evaluate outcomes of entecavir-treatment. Descriptive statistics were used to summarize patient demographics and treatment outcomes.

RESULTS

entecavir treatment reduced 24-h urinary protein excretion. The total probability of partial proteinuria and complete remission at 24 and 52 weeks was 53.1 and 78.1 %, respectively. A decrease of circulating HBV-DNA was observed in all patients with active HBV replication. The significant decrease of 24-h urinary protein began at 12 weeks, as early as the decrease of serum HBV-DNA level. The serum HBV DNA titers at baseline and after 52 weeks of treatment were 4.3 ± 2.8 log10 and 2.3 ± 1.7 log10, respectively. Meanwhile, eGFR increased from 100.3 ± 20.5 ml/min/1.73 m2 at baseline to 107.7 ± 15.9 ml/min/1.73 m2 after 52 weeks of treatment. The serum alanine aminotransferase level (ALT) gradually decreased to normal during entecavir antiviral treatment.

CONCLUSIONS

entecavir treatment in HBV-MN patients was carefully described. Complete remission and HBV replication suppression were induced by entecavir treatment in HBV-MN patients. Patients with high serum creatinine (Scr), ALT and low eGFR levels benefit more from entecavir treatment. Entecavir therapy is well tolerated by patients and no adverse reactions were observed.

Clinicopathological features, risk factors, and outcomes of immunoglobulin A nephropathy associated with hepatitis B virus infection

BACKGROUND

Hepatitis B virus (HBV) infections are associated with an increased risk of kidney diseases. However, the effects of HBV infection on the prognosis of immunoglobulin A nephropathy (IgAN) are unclear.

METHODS

A total of 838 patients with biopsy-confirmed IgAN were enrolled in this retrospective cohort study. The patients were categorized into either affected by IgAN and HBV infection (HBsAg-IgAN) or by primary IgAN with no sign of HBV infection (P-IgAN). A 1:1 propensity-score matching was performed between the two groups, followed by a Kaplan-Meier survival analysis, to compare the prognoses, and a Cox regression analysis, to identify factors influencing the HBsAg-IgAN outcomes.

RESULTS

A total of 176 pairs of patients were successfully matched. A significant difference in the systolic blood pressure and urea, serum creatinine, uric acid, and 24-h urine protein levels was observed between the groups. A renal pathological analysis also revealed a significant difference in the mesangial hypercellularity between the groups. During a median follow-up period of 2.4 years, Kaplan-Meier analysis also revealed a significant difference in the renal survival between the groups. Furthermore, multivariate Cox analysis confirmed that HBV infection is an independent risk factor for IgAN progression (hazard ratio [HR] 2.096; 95% confidence interval [CI] 1.091-4.026). Finally, the HBsAg-IgAN patients who received treatment with renin-angiotensin-aldosterone system inhibitors had a better overall prognosis than those who received immunosuppressive therapy and antiviral treatment.

CONCLUSION

Our results indicate that the clinicopathological features and outcomes of patients with IgAN differ significantly between those with and without HBV infection, and that HBV is an independent risk factor for IgAN progression.

Mechanisms of kidney dysfunction in the cirrhotic patient: Non-hepatorenal acute-on-chronic kidney damage considerations

Renal dysfunction is a common finding in cirrhotic patients and has a great physiologic, and therefore, prognostic relevance. The combination of liver disease and renal dysfunction can occur as a result of systemic conditions that affect both the liver and the kidney, although primary disorders of the liver complicated by renal dysfunction are much more common. As most of the renal dysfunction scenarios in cirrhotic patients correspond to either prerenal azotemia or hepatorenal syndrome (HRS), physicians tend to conceive renal dysfunction in cirrhotic patients as mainly HRS. However, there are many systemic conditions that may cause both a "baseline" chronic kidney damage and a superimposed kidney dysfunction when this systemic condition worsens. The main aim of this article is to review some of the most important non prerenal non-HRS considerations regarding acute on chronic kidney dysfunction in cirrhotic patients, including renal manifestation of related to non-alcoholic steatohepatitis (NASH) viral hepatitis, the effect of cardiorenal syndrome in cirrhotics and corticosteroid-deficiency associated renal dysfunction.

Secondary Membranous Nephropathy. A Narrative Review

Membranous nephropathy (MN) is a common cause of proteinuria and nephrotic syndrome all over the world. It can be subdivided into primary and secondary forms. Primary form is an autoimmune disease clinically characterized by nephrotic syndrome and slow progression. It accounts for ~70% cases of MN. In the remaining cases MN may be secondary to well-defined causes, including infections, drugs, cancer, or autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), urticarial vasculitis, sarcoidosis, thyroiditis, Sjogren syndrome, systemic sclerosis, or ankylosing spondylitis. The clinical presentation is similar in primary and secondary MN. However, the outcome may be different, being often related to that of the original disease in secondary MN. Also, the treatment may be different, being targeted to the etiologic cause in secondary MN. Thus, the differential diagnosis between primary and secondary MN is critical and should be based not only on history and clinical features of the patient but also on immunofluorescence and electron microscopy analysis of renal biopsy as well as on the research of circulating antibodies. The identification of the pathologic events underlying a secondary MN is of paramount importance, since the eradication of the etiologic factors may be followed by remission or definitive cure of MN. In this review we report the main diseases and drugs responsible of secondary MN, the outcome and the pathogenesis of renal disease in different settings and the possible treatments.

Quantitative Proteomics Reveals the Development of HBV-Associated Glomerulonephritis Triggered by the Downregulation of SLC7A7

As a hepadnavirus, hepatitis B virus (HBV) can cause damage to extrahepatic organs. The kidney is one of the organs that is more susceptible to damage. Research studies on HBV-associated glomerulonephritis (HBV-GN) have been going on for decades. However, the underlying molecular mechanism remains obscure. Here, we applied a tandem mass tag (TMT) isobaric labeling-based method to quantitatively profile the kidney proteome of HBV transgenic mice to illustrate the pathological mechanisms of HBV-GN. Weighted correlation network analysis, a clustering method for gene expression, is used to cluster proteins. Totally, we identified 127 proteins that were highly associated with HBV expression out of a total of 5169 quantified proteins. Among them, the downregulated solute carrier (SLC) family proteins are involved in the process of HBV-GN. We also found that IL1B was upregulated in the kidney tissue of HBV transgenic mice. These findings suggest that HBV disrupts the small molecule transport network of the kidney, which contributes to the occurrence of HBV-GN. The transporter, particularly SLC family 7 member 7 (SLC7A7), is involved in this process, which might serve as an intervention target for HBV-GN. All MS data have been deposited to the ProteomeXchange Consortium via the iProX partner repository with the data set identifier PXD016450.

Cordyceps sinensis attenuates HBx‑induced cell apoptosis in HK‑2 cells through suppressing the PI3K/Akt pathway

The authors' previous studies demonstrated that the major renal damage from hepatitis B virus infection is HBx‑induced apoptosis of renal tubular epithelial cells. Cordyceps sinensis is one of the most valuable of traditional Chinese medicines and is extensively used to treat chronic renal diseases. However, there is no research on the potential renal protective effect of C. sinensis on HBx‑induced apoptosis of renal tubular cells. The protective effect and underlying mechanism of C. sinensis were examined using a renal tubular epithelial cell line stably overexpressing HBx. HK‑2 cells were stably transfected with pCMV‑HBx to establish HBx‑overexpression in an in vitro cell model and HK‑2 cells transfected with an empty vector were generated as a control. The effect of C. sinensis on cell proliferation and apoptosis, the phosphatidylinositol‑3‑kinase (PI3K)/protein kinase B (Akt) signaling pathway, and the enzyme activity of caspase‑3 and caspase‑9 was measured. The present study demonstrated that HBx transfection inhibited cell proliferation; increased apoptosis, caspase‑3 and caspase‑9 activity; and increased the activity of the PI3K/Akt pathway. Treatment with C. sinensis attenuated all of these HBx‑induced responses. HBx triggered apoptosis and activated the PI3K/Akt signaling pathway in HK‑2 cells. C. sinensis treatment significantly attenuated the effect of HBx, at least in part by suppressing the PI3K/Akt signaling pathway.

Serum Hepatitis B Virus RNA: A New Potential Biomarker for Chronic Hepatitis B Virus Infection

Chronic hepatitis B infection is one of the major etiological causes of liver failure, cirrhosis, and hepatocellular carcinoma (HCC) worldwide. This condition cannot be completely cured by currently available drugs due to the persistent existence of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), the bona fide transcription template for HBV RNAs, in infected hepatocytes. Because quantifying cccDNA per se requires an invasive procedure, serum biomarkers reflecting intrahepatic cccDNA activity are warranted. Recently, a growing body of research suggests that the circulating HBV RNA may serve as a serum biomarker for HBV infection, treatment, and prognosis. In order to delineate the molecular and clinical characteristics of serum HBV RNA, we systematically reviewed the available literature on serum HBV RNA dating back to the early 1990s. In this review, we summarize the reported serum HBV RNA quantification methods and discuss the potential HBV RNA species in patient serum. We also compare the reported correlations of serum HBV RNA with other serological markers, including HBV DNA, hepatitis B surface antigen, e antigen, and core-related antigen, as well as their correlations with intrahepatic cccDNA, to assess their potential in clinical applications. Future directions for serum HBV RNA research are also discussed.

The histone demethylase LSD1 promotes renal inflammation by mediating TLR4 signaling in hepatitis B virus-associated glomerulonephritis

Renal inflammation significantly contributes to the progression of hepatitis B virus (HBV)-associated glomerulonephritis (HBV-GN), but the mechanisms that control its precise regulation remain largely unknown. In this study, we showed that the lysine-specific demethylase 1 (LSD1) was significantly upregulated in renal tissue of HBV-GN patients, and its expression was positively correlated with inflammation. Functionally, LSD1 could promote HBV-induced release of proinflammatory mediators in HK-2 cells, a human renal tubular epithelial (RTE) cell line. Mechanistic investigations suggested that LSD1 directly promoted the transcription of the inflammatory-related gene Tlr4 by eliminating the mono- or di-methylation of H3K9 near its promoter. Knockdown of Lsd1 further inhibited TLR4-NF-κB/JNK signaling cascades, and subsequently decreased HBV-induced production of proinflammatory mediators in HK-2 cells. Co-transfection with Tlr4-expressing plasmids counteracted these effects. Meanwhile, downregulation of abovementioned TLR4-related pathways using small-molecule inhibitors attenuated inflammation. Importantly, LSD1 inhibitor tranylcypromine (TCP) could inhibit TLR4-NF-κB/JNK signaling axis and alleviate renal inflammation in HBV transgenic mice. Taken together, our data identify LSD1 as a novel regulator of renal inflammation and as a potential therapeutic target in HBV-GN.

Hepatitis B virus infection and development of chronic kidney disease: a cohort study

Background

The effect of chronic hepatitis B virus (HBV) infection on the risk of chronic kidney disease (CKD) is controversial. We examined the prospective association between hepatitis B surface antigen (HBsAg) serology status and incident CKD in a large cohort of men and women.

Methods

Cohort study of 299,913 adults free of CKD at baseline who underwent health screening exams between January 2002 and December 2016 in South Korea. Incident CKD was defined as the development of an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m² and/or proteinuria.

Results

Over 1,673,701 person-years of follow-up, we observed 13,924 incident cases of CKD (3225 cases of eGFR < 60 ml/min/1.73m² and 11,072 cases of proteinuria). In fully adjusted models comparing positive to negative HBsAg participants, the hazard ratio (HR, 95% confidence interval) for incident CKD was 1.11 (1.03–1.21; P = 0.01). The corresponding HR for incident proteinuria and for eGFR < 60 ml/min/1.73m² were 1.23 (1.12–1.35; P <  0.001) and 0.89 (0.73–1.07; P = 0.21), respectively. The associations were similar across categories of liver enzyme levels at baseline.

Conclusion

In this large cohort, HBsAg positive serology was associated with higher risk of incident CKD, and we provide novel evidence that this association was due to a higher incidence of proteinuria in HBsAg positive participants. Our study adds to the growing body of evidence suggesting that chronic HBV infection may be a contributor to the increasing incidence of CKD.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1154-4) contains supplementary material, which is available to authorized users.

Combined effect of pegylated interferon α with adefovir on renal function in Chinese patients with chronic hepatitis B

BACKGROUND

Long-term safety of treatment with hepatitis B virus (HBV) polymerase inhibitors is a concern. Adefovir dipivoxil (ADV) and/or interferon alfa (IFN-α) therapies have previously been associated with impairment of renal function. Limited data are available on the safety of combination therapy with nucleos (t)ide analogues (NAs) and IFN-α. The aim of this analysis was to assess the renal function during combined therapy with pegylated interferon α-2b (PEG-IFN-α-2b) and ADV versus PEG-IFN-α-2b alone in patients with chronic hepatitis B (CHB).

METHODS

We performed a multicenter, prospective, open-label, randomized-controlled trial of renal function data to investigate the efficacy of 48 weeks of therapy with PEG-IFN-α-2b and ADV versus PEG-IFN-α-2b alone in 102 patients with CHB in Anhui, China. Glomerular filtration rates (GFRs) were calculated by Cockcroft-Gault (CG), abbreviated Modification of Diet in Renal Disease (MDRD) study, and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, and were tested by repeated-measures 1-way analysis of variance within groups. A linear mixed effects model for repeated measures was also used to evaluate the association between baseline information and estimated glomerular filtration rate (eGFR) changes overtime in all enrolled patients. The model considered the baseline age, sex, HBV DNA, aminotransferase, treatment group, time, and group-by-time interaction as fixed effects and incorporated random effects for individual subjects.

RESULTS

After 48 weeks of therapy and further 24 weeks of follow-up, the eGFR decreased both in patients given PEG-IFN-α-2b single therapy and combined therapy. Age, HBV DNA, and combined therapy were significant negative predictive factors for eGFR changes.

CONCLUSION

The incidence of renal adverse events in both groups was low, and the combination therapy may have delayed, but reversible renal impairment.

Hepatitis B virus X protein and proinflammatory cytokines synergize to enhance TRAIL-induced apoptosis of renal tubular cells by upregulation of DR4

Persistent infection with hepatitis B virus (HBV) may lead to HBV-associated glomerulonephritis (HBV-GN). Presence of HBV-DNA and -RNA in renal tubular epithelial cells (RTECs) suggests direct virus-induced injury. Increase in proinflammatory cytokines is also observed under these conditions. Apoptosis by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) plays a significant role in the pathogenesis of HBV-infections. However, the effects of HBV X protein (HBx) on TRAIL-induced apoptosis of RTECs especially under certain inflammatory conditions remain obscure. Here, we show that HBx synergizes with proinflammatory cytokines to significantly increase TRAIL-induced apoptosis of RTECs. HBx markedly up-regulates death receptor-4 (DR4) expression by enhancing the activation of nuclear factor-kappa B (NF-κB) in the presence of proinflammatory cytokines. Dramatic increase in DR4 expression leads to the sensitization of RTECs to TRAIL-induced apoptosis. Furthermore, in patients with HBV-GN, DR4 expression in the kidneys is significantly elevated and is positively correlated with the HBx and proinflammatory cytokines expression. These findings provide a novel insight into the underlying mechanisms of renal tubule lesions induced by HBx in HBV-GN.

The HBx gene of hepatitis B virus can influence hepatic microenvironment via exosomes by transferring its mRNA and protein

The cellular secretory vesicles known as 'exosomes' have emerged as key player in intercellular transport and communication between different eukaryotic in order to maintain body homeostasis. Many pathogenic viruses utilize exosome pathway to efficiently transfer bioactive components from infected cells to naïve cells. Here, we show that HBx can tweak the exosome biogenesis machinery both by enhancing neutral sphingomyelinase2 activity as well as by interacting with exosomal biomarkers such as neutral sphingomyelinase2, CD9 and CD81. The nano particle tracking analysis revealed enhanced secretion of exosomes by the HBx-expressing cells while confocal studies confirmed the co-localization of HBx with CD9 and CD63. Importantly, we observed the encapsulation of HBx mRNA and protein in these exosomes besides some other qualitative changes. The exosomal cargo secreted by HBx-expressing cells had a profound effect on the recipient hepatic cells including creation of a milieu conducive for cellular-transformation. Thus, the present study unfolds a novel role of HBx in intercellular communication by facilitating horizontal transfer of viral gene products and other host factors via exosomes in order to support viral spread and pathogenesis.

Effect of 48-week pegylated interferon α-2a or nucleos(t)ide analogue therapy on renal function in Chinese patients with chronic hepatitis B

Background

Controversy remains as to whether antiviral agents contribute to renal dysfunction in patients with chronic hepatitis B virus (HBV) infection. Thus, the aim of study was to analyze the changes in renal function of chronic hepatitis B (CHB) patients in response to anti-HBV therapy and the association with treatments.

Method

We performed a retrospective observational cohort study to investigate factors associated with renal function in 249 Chinese CHB patients who were treated with pegylated interferon α-2a (PEG-IFN-α-2a) or nucleos(t)ide analogues for 48 weeks. Changes of estimated glomerular filtration rate (eGFR), which was computed with both the Chronic Kidney Disease Epidemiology Collaboration and the Modification of Diet in Renal Disease formulas, were tested by repeated measures One-way analysis of variance within groups. A linear mixed effects model for repeated measures was also used to evaluate the association between baseline information and eGFR changes over time in all enrolled patients. The model considered the baseline age, sex, HBV DNA, aminotransferase, blood urea nitrogen, treatment group, time, and group-by-time interaction as fixed effects and incorporated random effects for individual subjects.

Results

The eGFR increased in patients given PEG-IFN-α-2a, decreased in patients given adefovir, but remained stable in patients given entecavir. Age and blood urea nitrogen were significant negative predictive factors for eGFR changes.

Conclusion

In real-life study, PEG-IFN-α-2a therapy in CHB patients increased eGFR, thus may associate with renoprotective effects when compared with adefovir or entecavir therapies.

Relationship between hepatitis B virus infection and chronic kidney disease in Asian populations: a meta-analysis

PURPOSE

To evaluate the association of Chronic hepatitis B virus (HBV) infection and chronic kidney disease (CKD).

METHODS

We searched Embase, Grateful Med, Ovid, PubMed, and the China Biological Medicine Database. A meta-analysis was performed to assess whether HBV infection plays an independent impact on the development of CKD in the general population. Relative risks of CKD (defined as reduced glomerular filtration rate or proteinuria) according to HBsAg serologic status were studied.

RESULTS

Six eligible clinical studies (189,709 individuals in total) were included in the analysis. There was no association between HBsAg seropositive status and prevalence of CKD, the summary estimate for adjusted relative risk (RR) was 1.16 (95% confidence interval (CI), 0.78, 1.71; p = .46) according to the random-effects model, and between studies heterogeneity was noted (p values by Q test <0.001). Also, there were no significant associations between positive HBV serologic status and low eGFR (adjusted relative risk, 0.95; 95% CI, 0.72, 1.26; p = .72) or proteinuria (adjusted relative risk, 1.00; 95% CI, 0.83, 1.20; p = .99).

CONCLUSIONS

This meta-analysis shows that there was no association between exposure to HBV and the risk of developing CKD in Asian populations.

Glomerular Detection of Schistosomal Antigen by Immunoelectron Microscopy in Human Mansonian Schistosomiasis

Schistosomal antigens (S. mansoni) were detected in glomeruli of nine patients with nephropathy and nephrotic syndrome by immunoelectron microscopy. The criteria for patients' selection were presence of intestinal schistosomiasis and absence of any surgical or other medical diseases, particularly lupus erythematosus, syphilis, and hepatitis B and C, which could explain the renal disease. When examined by light microscopy, kidney biopsies showed type I membranoproliferative glomerulonephritis in four patients, focal segmental glomerulosclerosis in two, and mesangioproliferative glomerulonephritis, membranous glomerulonephritis, and minimal change disease in one each of the remaining three patients. Immunofluorescence showed mainly immunoglobulin G (IgG), IgM, and different complement components (C3, Clq) deposits, particularly in the mesangial area, in eight patients. All patients had gold-labeled schistosomal antigen deposits in their glomeruli, chiefly in mesangial cells and matrix, along the glomerular membrane, and occasionally in the cytoplasm of epithelial cells. Although membranous glomerulonephritis has been rarely described in association with schistosomiasis and minimal change disease may be occasionally caused by an infectious disease like syphilis, the absence of definite experimental models and epidemiologic data suggests that coincidental pathologies without causal relationship with schistosomiasis cannot be ruled out to explain these findings.

Association between exposure to hepatitis B virus and chronic kidney disease in China

OBJECTIVE

Hospital-based, cross-sectional study to determine whether exposure to hepatitis B virus (HBV) has an independent effect on the risk of developing chronic kidney disease (CKD).

METHODS

Han Chinese adults undergoing routine physical examinations were recruited. Blood was tested for the presence of hepatitis C virus (HCV) antibodies, HBV surface antigen, and antibodies against HBV core antigen and hepatitis B surface antigen (HBsAg). CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m(2) or presence of albuminuria.

RESULTS

The prevalence of HBV exposure was 42.1% (6,418/15,259 participants). There were no significant associations between HBV or HCV status and CKD, low eGFR or albuminuria.

CONCLUSION

There was no association between exposure to HBV and the risk of developing CKD in this Chinese study population.

Glomerular Diseases Associated With Hepatitis B and C

Infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) are prevalent worldwide. In this review, we discuss the epidemiology, pathogenesis, clinical manifestations, and treatment of HBV- and HCV-related glomerulonephritis (GN). The most common histopathologic presentation of HBV-GN is HBV-associated membranous nephropathy, which usually manifests clinically with varying grades of proteinuria and microscopic hematuria. The pathogenesis is likely to be immune complex mediated; however, other host and viral factors have been implicated. The treatment of HBV-GN revolves around antiviral therapy. Various histologic types of glomerular diseases are reported in association with HCV infection, the most frequent being Type 1 membranoproliferative glomerulonephritis, usually in the context of Type 2 mixed cryoglobulinemia. The pathogenesis of HCV-GN can be attributed to glomerular deposition of cryoglobulins or noncryoglobulin-immune complexes. Cryoglobulins typically comprised immunoglobulin Mκ with rheumatoid factor activity. Clinically, patients may present with proteinuria, microscopic hematuria, hypertension, and acute nephritic and/or nephrotic syndrome. The treatment of HCV-GN, especially cryoglobulinemic membranoproliferative glomerulonephritis, encompasses various options including contemporary antiviral therapy with or without conventional and novel immunomodulatory agents.

13-year nationwide cohort study of chronic kidney disease risk among treatment-naïve patients with chronic hepatitis B in Taiwan

Background

Chronic hepatitis B virus (HBV) infection and chronic kidney disease (CKD) have high prevalences in Taiwan and worldwide. However, the association of untreated chronic hepatitis B virus (HBV) infection with chronic kidney disease (CKD) remains unclear.

Methods

This cohort study used claims data in the Taiwan National Health Insurance Research Database in 1996–2010, in which all diseases were classified by ICD-9-CM codes. We identified 17796 adults who had chronic HBV infection and did not take nucleos(t)ide analogues from 1998 to 2010 and also randomly selected 71184 matched controls without HBV in the same dataset. Cumulative incidences and adjusted hazard ratio (aHR) of incident CKD were evaluated through the end of 2010 after adjusting for competing mortality.

Results

The risk of CKD was significantly higher in the HBV cohort (13-year cumulative incidence, 6.2 %; 95 % confidence interval [CI], 5.4–7.1 %) than in the non-HBV cohort (2.7 %; 95 % CI, 2.5–3.0 %) (p < 0.001), and the aHR was 2.58 (95 % CI, 1.95-3.42; p < 0.001). Multivariable stratified analysis further verified significant associations of CKD with HBV in men of any age (aHR, 2.98; 95 % CI, 2.32–3.83, p < 0.001 for men aged <50 years; aHR, 1.58; 95 % CI, 1.31–1.91, p < 0.001 for men aged ≧50 years) and women under the age of 50 (aHR, 2.99; 95 % CI, 2.04–4.42, p < 0.001), but no significant association in women aged 50 or over.

Conclusion

Untreated chronic HBV infection is associated with increased risk of CKD. Hence, high-risk HBV-infected subjects should have targeted monitoring for the development of CKD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0106-5) contains supplementary material, which is available to authorized users.

A nationwide cohort study suggests chronic hepatitis B virus infection increases the risk of end-stage renal disease among patients in Taiwan

The association of chronic hepatitis B virus (HBV) infection with end-stage renal disease (ESRD) is unclear. To help clarify this we conducted a nationwide cohort study to measure the association by analyzing the claims data from the Taiwan National Health Insurance Research Database with ICD-9 codes used to identify diseases. We identified 17,758 adults who had chronic HBV infection and had not taken nucleos(t)ide analogs from 1999 to 2010 and randomly selected 71,032 matched controls without HBV in the same data set. The risk of ESRD was compared between these two cohorts. Cumulative incidences and hazard ratios were calculated after adjusting for competing mortality. The risk of ESRD was significantly higher in the HBV cohort (12-year cumulative incidence, 1.9%) than in the non-HBV cohort (0.49%) with a significant adjusted hazard ratio of 3.85. Multivariable stratified analysis further verified significant associations of ESRD with HBV in men of any age and women under the age of 60 years, but no significant association in women aged ⩾60 years. Thus, a large national cohort study indicates that untreated chronic HBV infection is associated with increased risk of ESRD. Hence, high-risk HBV-infected patients should have targeted monitoring for the development of ESRD.

Purified hepatitis B virus induces human mesangial cell proliferation and extracellular matrix expression in vitro

Background

Hepatitis B virus (HBV) induces proliferation of human mesangial cells (HMCs), and extracellular matrix expression through the deposition of immune complexes in renal tissue. However, it is unclear whether HBV can directly affect HMCs. In this study, the effects of purified HBV on HMC proliferation and extracellular matrix expression in vitro was determined.

Findings

HBV was purified using sucrose density gradient centrifugation. HMCs were co-cultured with purified HBV (10⁴–10⁶ copies/ml) for 48 h, and cell proliferation determined using 5-ethynyl-2′-deoxyuridine immunofluorescence assays. After HMCs were co-cultured with 10⁶ copies/ml purified HBV for 0, 12, 24, 36 and 48 h, expression of type IV collagen and fibronectin was measured using enzyme-linked immunosorbent assays. Three titers of purified HBV (10⁴, 10⁵, and 10⁶ copies/ml) induced HMC proliferation, with the proportion of increases in cell numbers at 24.7 ± 4.3, 31.2 ± 9.4, and 36.8 ± 7.5%, respectively. All these increases were significantly higher than those for the control group (13.6 ± 4.2%) (All p < 0.05). Purified HBV (10⁶ copies/ml) significantly increased the levels of type IV collagen and fibronectin in supernatants compared with the control group at 12 and 48 h (All p < 0.05).

Conclusions

Purified HBV can directly promote HMC proliferation and expression of type IV collagen and fibronectin, and could be involved in the pathogenesis of HBV-associated glomerulonephritis.

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.

Hepatitis B virus X protein modulates apoptosis in human renal proximal tubular epithelial cells by activating the JAK2/STAT3 signaling pathway

Hepatitis B virus X protein (HBx) is a multifunctional protein, and it activates multiple signal transduction pathways in multiple types of cells and regulates the process of cell apoptosis. In the present study, we mainly investigated the correlation between HBx and renal tubular epithelial cell apoptosis in hepatitis B virus-associated glomerulonephritis (HBVGN) and the possible signaling mechanism. Cell apoptosis in nephridial tissues of patients with HBVGN were determined by the TUNEL method. HBx, p-STAT3 and STAT3 levels in nephridial tissues were determined by immunohistochemical assay, and a correlation analysis between HBx expression levels and apoptosis index in nephridial tissues was conducted. The activation of the JAK2/STAT3 signaling pathway in HK-2 cells and the expression of the apoptosis-related proteins Bax and Bcl-2 were determined by western blot analysis following transfection with the HBx eukaryotic expression vector. Cellular proliferation activity was determined by the CCK-8 method, and cell apoptosis was determined with HO33342 staining using transmission electron microscopy and Annexin V/PI double staining flow cytometry. The results revealed that the apoptosis index in nephridial tissues of patients with HBVGN was significantly higher when compared to that of the control group, and p-STAT3 expression levels in HBVGN nephridial tissues were significantly increased. In the control group, no HBx expression was observed in the nephridial tissues, whereas HBx expression was found in the nephridial tissues of 86% of the patients with HBVGN. The HBx expression levels had a linear correlation with the apoptosis index in the nephridial tissues. After target gene HBx infection, expression levels of both p-JAK2 and p-STAT3 in human proximal HK-2 cells were significantly increased, and the Bax/Bcl-2 ratio was also significantly increased. At the same time, cellular proliferation of HK-2 cells was significantly inhibited, and the rate of apoptosis was increased. After incubation with AG490, the JAK2/STAT3 signaling pathway was partially blocked, which caused a decrease in the Bax/Bcl-2 ratio and reduced cell apoptosis caused by HBx. In conclusion, HBx upregulates the Bax/Bcl-2 ratio by activating the JAK2/STAT3 signaling pathway to cause renal tubular epithelial cell apoptosis, and it is possibly involved in the pathogenic mechanism of nephridial tissue damage caused by HBV.

A case of adefovir-induced membranous nephropathy related to hepatitis B caused by lamivudine-resistant virus after liver transplant due to Byler's disease

We report on how adefovir-induced membranous nephropathy related to hepatitis B was caused by lamivudine-resistant virus after a liver transplant due to Byler's disease. In 1980, a 2-year-old girl was diagnosed with Byler's disease (familial progressive familial intrahepatic cholestasis). In 1994 (at the age of 14 years) she underwent a liver transplant with her father as the donor. In 2003, hematuria and proteinuria appeared and shortly afterwards her renal function rapidly decreased. A renal biopsy showed atypical membranous nephropathy, which suggested the possibility of a secondary renal disease. The patient had suffered from chronic hepatitis type B (HBV). In 2001 she was administered lamivudine which is an antiviral drug; it was around this time that hematuria and proteinuria appeared as well as an increase of the virus titer. We believed the HBV-related membranous nephropathy was the cause of the virus titer and the renal histology. We concluded that the patient's condition had become resistant to lamivudine medication. Therefore, in February 2004 we administered adefovir, a new drug at the time, to treat the HBV. In April 2004, the HB virus titer decreased and the hematuria and proteinuria decreased. The patient's renal function also showed improvement. HBV-associated nephropathy is caused by HBV antigen deposition in the glomeruli. Generally the first choice of treatment is antivirus therapy. There are many reports demonstrating that administration of interferon and lamivudine are effective; however, there are few reports that show adefovir as an effective treatment for HBV-associated nephropathy.

Successful treatment of hepatitis B virus associated nephrotic syndrome with oral Lamivudine in a Nigerian child: a case report

Hepatitis B virus is a well described cause of nephrotic syndrome (NS) worldwide, the typical lesion being membranous glomerulonephropathy. HBV associated NS has been successfully treated with intravenous alpha interferon (IFN), an anti-viral agent. In recent times there have been reports of treatment with lamivudine, an orally administered nucleoside analogue inhibitor of HBV DNA polymerase in Caucasian children. Data is however limited and it's actual efficacy and safety in children is yet to be determined. We present the case of an 8-year-old Nigerian boy with NS and active hepatitis B virus infection. He went into remission 3 months after commencing oral lamivudine which he had for a year with no significant side effects observed. He remains in remission 3 years later. This, to our knowledge is the first report in literature of successful treatment in an African child.

Hepatitis B virus-associated antigen deposition in renal tissue from patients with systemic lupus erythematosus

OBJECTIVE

To determine the significance of hepatitis B virus (HBV)-associated antigen deposition in renal tissue from patients with systemic lupus erythematosus (SLE).

METHODS

The medical records of 166 inpatients with lupus nephritis and 384 controls without SLE were analyzed retrospectively. Patients with SLE were classified as positive or negative depending on whether HBV-associated antigen deposition was detected in renal biopsies.

RESULTS

HBV-associated antigen deposition was mainly detected in renal tissue from patients with SLE (50.6%), primary renal glomerular disease (20.8%), and allergic purpura (21.7%). It was not detected in renal tissue from patients with diabetic nephropathy, hypertensive nephrosclerosis, thin basement membrane nephropathy, or Alport syndrome. Hepatitis B surface antigen and core antigen were deposited in the mesangial region and vascular loops. The positive group had a significantly higher frequency of IgG, IgA, and IgM deposition than the negative group (53.6% vs 30.5%; p < 0.01). There was no significant difference in the types of lupus nephritis observed between the 2 groups.

CONCLUSION

There was a high prevalence of HBV-associated antigen deposition in renal tissue of patients with SLE by indirect immunofluorescence, which may result mainly from the cross-reactivity with deposited immunoglobulins.

Hepatitis-related renal disease

Many glomerular diseases can be caused by viral infections based on the diagnostic criteria, including clinical and laboratory data, and molecular analysis of tissue. Operative pathogenetic mechanisms include kidney tropism of the virus, immune complex formation, direct cytopathogenic effect, and multi-organ failure. Chronic infection with hepatitis virus is etiologically linked to well-defined glomerulopathies. In endemic areas, HBV is associated with both membranous nephropathy and mesangiocapillary glomerulonephritis, while HCV is known to cause cryoglobulinemia-mediated glomerulonephritis and other forms of glomerulonephritis. Renal biopsy with appropriate serological and molecular testing helps to define virus-related glomerular lesions and provides a prognostic and therapeutic guide. Antiviral agents remain the mainstay of treatment.

Hepatitis B virus-associated glomerular nephritis in East Asia: progress and challenges

BACKGROUND

Hepatitis B virus-associated glomerular nephritis (HBV-GN) is the most common secondary glomerulonephritis in East Asia. Part of the patients developed to renal insufficiency within 10 years, which cause a great burden for patients' family and society.

METHODS

We reviewed basic and clinical research work in China, Japan, Korea, and Mongolia, eastern part of Asia. Comparisons between data from East Asia and those from other regions were made.

RESULTS

The genetic variations conferring susceptibility to HBV-GN and disease progression as well as the pathogenic role in HBV-GN progression were investigated. Clinical features of HBV-GN in East Asia were different from that of other regions in the world. Clinical trials showed that treatment with anti-viral agents was effective to promote the disease remission.

CONCLUSION

HBV-GN remains a great challenge to East Asian nephrologists. In-depth basic studies and multi-centered clinical trials are needed in the future.

Association of hepatitis C and B virus infection with CKD in an endemic area in Taiwan: a cross-sectional study

BACKGROUND

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections may lead to nephropathy. However, the association between different types of viral hepatitis and chronic kidney disease (CKD) is not well established.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

A large-scale community study with 54,966 adults in a Taiwanese county endemic for HBV and HCV infection.

PREDICTOR

HCV infection alone, HBV infection alone, HBV/HCV coinfection, and neither.

OUTCOMES

Proteinuria (urine protein, >or=1+), low (<60 mL/min/1.73 m(2)) estimated glomerular filtration rate (eGFR), and CKD (proteinuria or eGFR <60 mL/min/1.73 m(2)).

MEASUREMENTS

HBV and HCV infection were defined as a seropositive test result for hepatitis B surface antigen and HCV antibody. Proteinuria was assessed using a repeated dipstick method. eGFR was computed using the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation.

RESULTS

Mean age of the study group was 60.8 years. Prevalences of HCV infection alone, HBV infection alone, HBV/HCV coinfection, and neither were 9.4%, 9.9%, 0.9%, and 79.8%, respectively. 2,994 (5.4%), 7,936 (14.5%), and 9,602 (17.5%) participants had proteinuria, low eGFR, and CKD, respectively. Multivariate logistic regression analyses showed that HCV infection alone (OR, 1.26; 95% CI, 1.17-1.38), but not HBV infection alone (OR, 1.04; 95% CI, 0.96-1.14) or HBV/HCV coinfection (OR, 1.12; 95% CI, 0.87-1.45), was an independent risk factor for CKD. The prevalence of HCV seropositivity was higher in later CKD stages, changing from 8.5% in CKD stage 1 to 14.5% in CKD stages 4-5. Adjusted ORs for HCV infection alone were 1.14 (95% CI, 1.003-1.300) for proteinuria and 1.30 (95% CI, 1.20-1.42) for low eGFR.

LIMITATIONS

The definition of CKD status requires a 3-month duration of low eGFR or kidney damage; this was presumed, not documented, in this study.

CONCLUSIONS

HCV infection, but not HBV infection, was associated significantly with prevalence and disease severity of CKD in this HBV and HCV endemic area.

Hepatitis B-related autoimmune manifestations

This article focuses on autoimmune manifestations related to the hepatitis B virus (HBV). Although the HBV vaccination has resulted in the decline of the virus, approximately 400 million individuals are infected worldwide. Up to twenty percent of the afflicted may develop extrahepatic manifestations ranging from the severe polyarteritis nodosa to the many, varied, and less severe clinical and biologic forms. Currently, control of the viral infection is mainly based on the use of antiviral drugs (with the current availability of potent agents). Discussion of two hypotheses of the pathophysiology of the virus is followed by descriptions of the general, renal, rheumatologic, neurologic, skin, ophthalmologic, and hematologic manifestations.

Systemic abnormalities in liver disease

Systemic abnormalities often occur in patients with liver disease. In particular, cardiopulmonary or renal diseases accompanied by advanced liver disease can be serious and may determine the quality of life and prognosis of patients. Therefore, both hepatologists and non-hepatologists should pay attention to such abnormalities in the management of patients with liver diseases.

Expression of APOBEC3G in kidney cells

The apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G (APOBEC3G), a member of the APOBEC family possessing DNA mutator activity through cytosine deamination, is reported to play an important role in host defense against infections such as those of hepatitis B virus and human immunodeficiency virus. Here, we examined the expression of APOBEC3G in human kidney cells to better understand its biological role against infection. APOBEC3G was immunohistochemically detectable in kidney mesangial cells and also to some extent in kidney epithelial tubular cells. In addition, overexpression of APOBEC3G was shown in renal carcinoma tissues and cell lines. APOBEC3G expression was upregulated by inflammatory cytokines, such as interferon, interleukin-6, and tumor necrosis factor. These results may provide new insight into the role of APOBEC3G in host defense against viral infection and cancer.

Meta-analysis: anti-viral therapy of hepatitis B virus-associated glomerulonephritis

BACKGROUND

Hepatitis B virus-associated glomerulonephritis is an infrequent complication of chronic hepatitis B virus (HBV) with significant morbidity. A causal association between hepatitis B virus infection and the development of glomerulonephritis remains controversial. Also, the optimal therapy is undefined although several approaches have been made.

AIM

To evaluate the efficacy and safety of anti-viral therapy (interferon or lamivudine) in HBV-associated glomerulonephritis by a systematic review and meta-analysis of clinical trials.

METHODS

The primary outcome was clinical response (as a measure of efficacy); the secondary outcomes were drop-out rate (as a measure of tolerability), and virological response. We used the random effects model of DerSimonian and Laird, with heterogeneity, sensitivity and meta-regression analyses.

RESULTS

We identified six clinical trials (84 unique patients); three had controlled design. The overall estimate for proteinuria remission was 65.2% (95% confidence intervals: 52.7-75.9%), Q-test for heterogeneity = 7.731, P = 0.172, I(2) = 35.327. The overall estimate for hepatitis B e antigen clearance was 62.0% (95% confidence intervals: 50.5-72.2%). The overall estimate for drop-out rate was 12.7% (95% confidence intervals: 6.4-23.6%). Meta-regression analysis showed a significant link between hepatitis B e antigen clearance and logit rate of proteinuria remission after interferon therapy [coefficient -2.585 (S.E. 1.089), P = 0.017].

CONCLUSION

Remission of the nephrotic syndrome is accompanied by clearance of HBV replication, supporting the role of the virus in the pathogenesis of the disease.

Study on hepatitis B virus pre-S/S gene mutations of renal tissues in children with hepatitis B virus-associated membranous nephropathy

This study aims to clarify the prevalence and significance of the emergence of hepatitis B virus (HBV) pre-S/S mutations in children with hepatitis B virus-associated membranous nephropathy (HBVMN). Direct sequencing of polymerase chain reaction products of renal tissue samples that were obtained via percutaneous renal biopsy from seven children revealed the presence of HBV DNA. Seven adr subtypes were analyzed. Deletions in the HBV pre-S region were observed once per seven patients. The deletions were noted in both the pre-S1 (27 bp) and pre-S2 (60 bp) regions. Various point mutations in the HBV pre-S region were detected in all seven patients and proved to be more frequent in the pre-S1 region than in the S2 region. Point mutations in the HBV S region were detected in six patients. Among these mutations, the mutation in the "a" determinant region was noted in five patients. No deletion, however, was observed in the HBV S region. These observations suggested that deletions and point mutations in the HBV pre-S1 and pre-S2 regions and point mutations in the HBV S region, especially the "a" determinant region, are common frequent findings. These results also suggested that HBV pre-S/S region mutations may be involved in the pathogenesis in children with HBVMN.

Gene expression profile of transgenic mouse kidney reveals pathogenesis of hepatitis B virus associated nephropathy

Hepatitis B virus (HBV)-associated nephritis has been reported worldwide. Immune complex deposition has been accepted as its pathogenesis, although the association between the presence of local HBV DNA and viral antigen and the development of nephritis remains controversial. To understand better the roles played by HBV protein expression in the kidney, the global gene expression profile was studied in the kidney tissue of a lineage of HBV transgenic mouse (#59). The mice expressed HBsAg in serum, and HBsAg and HBcAg in liver and kidney, but without virus replication. Full-length HBV genome (adr subtype, C genotype) isolated from a chronic HBV carrier was used to establish the transgenic mice #59. Similarly manipulated mice that did not express HBV viral antigens served as controls. Southern blotting, hybridization with HBV probe, and immuno-histochemical staining were used to study HBV gene expression. mRNA extracted from the kidney tissue was analyzed using Affymetrix microarrays. HBsAg and HBcAg were located mainly in the cytoplasm of tubular epithelium. Altogether 520 genes were "up-regulated" more than twofold and 76 genes "down-regulated" more than twofold in the kidney. The complement activation, blood coagulation, and acute-phase response genes were markedly "up-regulated". Compared to the controls, the level of serum C3 protein was decreased in #59 mice, while the level of C3 protein from kidney extract was increased. Results indicate that expression of HBsAg and HBcAg in tubular epithelial cells of the kidney per se can up-regulate complement-mediated inflammatory gene pathways, in addition to immune complex formation.

Existence and significance of hepatitis B virus DNA in kidneys of IgA nephropathy

AIM

To investigate the existence and significance of hepatitis B virus (HBV) DNA in the pathogenesis of IgA nephropathy (IgAN).

METHODS

Fifty cases of IgAN with HBV antigenaemia and/or hepatitis B virus antigens (HBAg, or HBsAg, HBcAg) detected by immunohistochemistry in renal tissues were enrolled in our study. The distribution and localization of HBV DNA were observed using in situ hybridization. Southern blot analysis was performed to reveal the state of renal HBV DNA.

RESULTS

Among the 50 patients with IgAN, HBs antigenemia was detected in 17 patients (34%). HBAg in renal tissues was detected in 48 patients (96%), the positive rate of HBAg, HBsAg, and HBcAg was 82% (41/50), 58% (29/50), and 42% (21/50) in glomeruli, respectively; and was 94% (47/50), 56% (28/50) and 78% (39/50) in tubular epithelia, respectively. Positive HBV DNA was detected in 72% (36/50) and 82% (41/50) cases in tubular epithelia and glomeruli respectively by in situ hybridization, and the positive signals were localized in the nuclei of tubular epithelial cells and glomerular mesangial cells as well as infiltrated interstitial lymphocytes. Moreover, 68% (34/50) cases were proved to be HBV DNA positive by Southern blot analysis, and all were the integrated form.

CONCLUSION

HBV infection might play an important role in occurrence and progress of IgAN. In addition to humoral immune damages mediated by HBAg-HBAb immune complex, renal tissues of some IgAN are directly infected with HBV and express HBAg in situ, and the cellular mechanism mediated by HBV originating from renal cells in situ may also be involved in the pathogenesis of IgAN.