Hepatitis B virus replication within the human spleen

Spleen elastography in patients with Systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune inflammatory connective tissue disease. It is characterized by varying degrees of fibrosis of the skin and internal organs. Tissue fibrosis is the final phase of a complex biological process of immune activation and vascular damage. The spleen is one of the organs thought to be involved in a systemic fibrosing process. Yet, there is a lack of research that provides evidence about splenic involvement in patients with SSc through objective instrumental techniques. Ultrasound elastography is a modern method which detects changes in the stiffness and elasticity of different organs. To assess the elasticity and stiffness of the spleen in healthy subjects and patients with SSc, the study included 34 patients with SSc and 35 healthy volunteers. Point SWE spleen elastography was performed on all participants in the two study groups through an Esaote MyLab 9 eXP with a C1-8 iQ appleprobe transducer. The mean age in the SSc patient group was 47.35 ± 11.48 years vs. 46.20 ± 14.55 years in the healthy controls, with no significant age difference, p = 0.717. The mean Body Mass Index (BMI) in the SSc patient group was 22.42 ± 2.12 kg/m² vs. 24.23 ± 4.29 kg/m² in the healthy control group with no significant difference, p = 0.410. Among the SSc patients, 18(53%) were with dcSSc and 16 (47%) with lcSSc. The mean disease duration was 59 ± 28 months, ranging between 18 and 118 months. Spleen stiffness median was significantly higher in the SSc patient group (3.19 m/s) in comparison with the healthy controls (2.40 m/s), p < 0.001. Spleen size was normally distributed and did not differ significantly between the SSc patients (105.84 ± 7.87 mm) and the healthy controls (104.16 ± 8.99 mm), p = 0.410. A significantly higher mean of spleen stiffness was observed in the dcSSc patients (3.38 ± 0.20 m/s) in comparison with the lcSSc group (2.81 ± 0.38 m/s), p < 0.001. Spleen size did not show a significant association with the type of SSc. Spleen size in the dcSSc subgroup had a mean value of 103.45 ± 5.56 mm vs. 108.51 ± 9.30 in the lcSSc subgroup, p = 0.071. pSWE is an objective, reliable, and easy-to-implement method for detecting early fibrous changes in the spleen in patients with SSc. A good approach in patients with SSc could be the search for similar processes in other internal organs, such as the liver and thyroid gland.

Review article: preventing hepatitis B graft infection in hepatitis B patients after liver transplantation: immunoglobulin vs anti-virals

BACKGROUND

A critical aspect of liver transplantation in hepatitis B patients is to prevent graft reinfection with hepatitis B virus. The use of hepatitis B immune globulin after transplant was a significant milestone, which allowed prolonged graft and patient survival by controlling hepatitis B reinfection in liver grafts. The development of anti-viral treatments with oral nucleos(t)ide analogues, led to a further reduction in graft reinfection and improvement in patient survival. The combination of the aforementioned two therapies has been widely used in hepatitis B-associated liver transplants.

AIMS

To address the post-transplant management of hepatitis B and provide updates on preventing graft reinfection.

METHODS

We performed a literature search on Ovid and PubMed for randomised controlled trials or cohort studies in English, which investigated the effectiveness of hepatitis B immune globulin and anti-viral therapy on hepatitis B-associated transplants (1/2000-1/2020). Studies that met pre-established criteria were reviewed.

RESULTS

Based on currently available evidence, an algorithm for post-transplant management with anti-viral therapy is proposed. Also, the management of recipients who received grafts from hepatitis B core antibody-positive donors is discussed.

CONCLUSIONS

The development of hepatitis B immune globulin and anti-viral treatments led to substantial improvement in graft and patient survival. The prevention of hepatitis B graft reinfection is complex and involves a broad interdisciplinary team.

Clinical applications of spleen ultrasound elastography - a review

In the last few years, notable technical progress has taken place in ultrasound elastography. Qualitative methods have been replaced by quantitative ones, such as: transient elastography, acoustic radiation force impulse and shear wave elastography. Owing to the fact that the spleen is superficially located, it is possible to obtain reliable measuring accuracy of its hardness using sonoelastography. Lately, many researchers have been investigating how spleen elasticity changes in patients infected with hepatitis B virus or hepatitis C virus and in patients suffering from liver fibrosis, portal hypertension, esophageal varices or myelofibrosis. In this article, we review the role and current status of accessible qualitative ultrasound elastography methods, including recent advances in the evaluation of spleen stiffness and its clinical utility. As study results demonstrate, spleen stiffness correlates with liver fibrosis and is helpful in determining the level of fibrosis in the METAVIR scoring system. In patients infected with hepatitis B virus or hepatitis C virus, spleen stiffness increases even when liver elasticity remains unaltered. Furthermore, it is useful in diagnosing portal hypertension or predicting existence of esophageal varices. Moreover, in patients suffering from biliary atresia after Kasai portoenterostomy, spleen sonoelastography may be helpful in selecting patients for liver transplantation as well as for choosing the best strategy for portal vein reconstruction before liver transplantation. In myelofibrosis, spleen stiffness correlates with bone marrow fibrosis and may be used to assess the response to treatment. Spleen sonoelastography is also useful in the monitoring of transjugular intrahepatic portosystemic shunt function.

Shear wave elastography (SWE) of the spleen in patients with hepatitis B and C but without significant liver fibrosis

OBJECTIVE

The aim of the study was to compare the elasticity of the spleen in patients with hepatitis B and C but without liver fibrosis with that of healthy subjects using a shear wave elastography (SWE) examination.

METHODS

Between December 2014 and December 2015, 35 patients with hepatitis B virus (HBV) infections and 45 patients with (hepatitis C virus) HCV infections and liver stiffness below 7.1 kPa were included in the study. The control group was composed of 53 healthy volunteers without any chronic liver disease, with no abnormal findings in their ultrasound examinations and with an SWE of the liver below 6.5 kPa. The SWE measurements were a part of routine ultrasound abdominal examinations. The examinations were performed using an Aixplorer device by two radiologists with at least 6 years' experience. To compare spleen stiffness between the groups, the Mann-Whitney U-test was applied. To analyze the dependency between liver and spleen elasticity, Spearman's rank correlation coefficient was calculated.

RESULTS

A total of 133 SWE findings were analyzed. Stiffness of the spleen was significantly higher in patients with HBV and HCV but without significant liver fibrosis than it was in the healthy controls (p = 0.0018 and 0.0000, respectively). This correlation was also present in patients with liver stiffness below 6.5 kPa (p = 0.0041 and 0.0000, respectively). Analysis revealed no significant correlation between liver and spleen stiffness in patients with hepatitis B and C and without significant fibrosis (p = 0.3216 and 0.0626, respectively).

CONCLUSION

Patients with hepatitis B and C but without significant liver fibrosis have stiffer spleens than healthy controls. There is no dependency between liver and spleen elasticity in patients without significant fibrosis.

ADVANCES IN KNOWLEDGE

The SWE examination might be an important tool and could be used in addition to conventional imaging. Our study may become a starting point in further investigations into the role of the spleen in HCV and HBV infections and perhaps into introducing spleen elastography into diagnostic and follow-up procedures.

Outcomes including liver histology after liver transplantation for chronic hepatitis B using oral antiviral therapy alone

The outcomes of hepatitis B virus (HBV)-related hepatitis after liver transplantation (LT) without hepatitis B immune globulin (HBIG) is not well documented. This study aims to determine the outcomes of chronic hepatitis B (CHB) patients using an HBIG-free regimen. All biopsies performed 3 months or more after LT in consecutive CHB patients transplanted from 2003 to 2012 were reviewed. None of the patients received HBIG. Results of all liver histologies were reviewed to determine the cause of graft dysfunction. Of the 435 patients transplanted during this period, 263 liver biopsies were performed in 144 patients. Thirty-six patients were positive for hepatitis B surface antigen (HBsAg) with undetectable HBV DNA at the time of biopsy, and none had histological evidence of HBV infection. Of the 263 biopsies, 44 (17%) had evidence of fibrosis. There was a significantly higher rate of fibrosis in those with large duct obstruction compared to those without (51% versus 9%, respectively; P < 0.001). Of the 291 patients without a liver biopsy during the same period, 43 were HBsAg+. Seven patients had evidence of virological rebound, of whom 6 had evidence of rtM204V/I mutation and 1 had recurrence of hepatocellular carcinoma with low-level rebound and wild-type virus. In conclusion, for patients without virological rebound, positive serum HBsAg was not associated with histological evidence of HBV-related hepatitis after LT. To prevent virological rebound, nucleos(t)ide analogues with higher barriers to resistance should be used.

Drug delivery systems and liver targeting for the improved pharmacotherapy of the hepatitis B virus (HBV) infection

In spite of the progress made in vaccine and antiviral therapy development, hepatitis B virus (HBV) infection is still the most common cause of liver cirrhosis and hepatocellular carcinoma, with more than 400 million people chronically infected worldwide. Antiviral therapy with nucleos(t)ide analogues and/or immunomodulating peptides is the only option to control and prevent the progression of the disease in chronic hepatitis B (CHB)-infected patients. So far, the current antiviral monotherapy remains unsatisfactory because of the low efficacy and the development of drug resistance mutants. Moreover, viral rebound is frequently observed following therapy cessation, since covalent closed circular DNA (cccDNA) is not removed from hepatocytes by antiviral therapy. First, this review describes the current pharmacotherapy for the management of CHB and the new drug candidates being investigated. Then, the challenges in the development of drug delivery systems for the targeting of antiviral drugs to the liver parenchyma are discussed. Finally, perspectives in the design of a more efficient pharmacotherapy to eradicate the virus from the host are addressed.

Synthesis, analysis, in vitro characterization, and in vivo disposition of a lamivudine-dextran conjugate for selective antiviral delivery to the liver

A liver-selective prodrug (3TCSD) of the antiviral drug lamivudine (3TC) was developed and characterized. 3TC was coupled to dextran ( approximately 25 kDa) using a succinate linker, and the in vitro and in vivo behavior of the conjugate was studied using newly developed size-exclusion and reversed-phase analytical methods. Synthesized 3TCSD had a purity of >99% with a degree of substitution of 6.5 mg of 3TC per 100 mg of the conjugate. Furthermore, the developed assays were precise and accurate in the concentration ranges of 0.125-20, 0.36-18, and 1-50 microg/mL for 3TC, 3TC succinate (3TCS), and 3TCSD, respectively. In vitro, the conjugate slowly released 3TC in the presence of rat liver lysosomes, whereas it was stable in the corresponding buffer. In vivo in rats, conjugation of 3TC to dextran resulted in 40- and 7-fold decreases in the clearance and volume of distribution of the drug, respectively. However, the accumulation of the conjugated 3TC in the liver was 50-fold higher than that of the parent drug. The high accumulation of the conjugate in the liver was associated with a gradual and sustained release of 3TC in the liver. These studies indicate the feasibility of the synthesis of 3TCS-dextran and its potential use for the selective delivery of 3TC to the liver.

Cell type-specific mechanisms regulate hepatitis B virus transgene expression in liver and other organs

Intracellular expression of hepatitis B virus (HBV) was analysed in transgenic HBV mouse lines designated G7 and G26, the former lacking hepatitis B surface antigen (HBsAg) promoters. HBsAg mRNA expression was greater in the G26 line than in the G7 line, although in situ hybridization showed a qualitatively similar expression pattern in specific cell types. HBsAg mRNA was most abundant in hepatocytes, followed in magnitude by proximal renal tubular epithelial cells, pancreatic acinar cells, and epithelial cells of the gastric, small intestinal, and bronchiolar mucosae. In biliary epithelial cells, brain, spleen, large intestine, testis, heart, and skeletal muscle, HBsAg mRNA was undetectable. In cell transfection assays, the HBV enhancer/preS1 promoter efficiently expressed a luciferase reporter with appropriate upregulation by HNF-3 alpha and C/EBP alpha transcription factors in hepatocyte-derived cells but not in non-parenchymal epithelial liver cells or fibroblasts. These results suggest that cell-type specificity of HBV expression is regulated by interactions between viral elements and cellular transactivators. Variable expression of G7 and G26 HBV transgenes in epithelial cells combined with differences in transgene expression in similar sets of cells suggests at least two levels of regulation: one directing cell specificity of HBV expression and the other governing quantitative expression of HBV mRNA.

Improved outcome of orthotopic liver transplantation for chronic hepatitis B cirrhosis with aggressive passive immunization

Passive immunization with hepatitis B surface antibody (anti-HBs) is important to prevent hepatitis B virus (HBV) recurrence after orthotopic liver transplantation for chronic HBV cirrhosis. Hepatitis B immune globulin (HBIG) dosing regimens have been poorly defined, utilize numerous routes of administration, and result in a high rate of HBV relapse and mortality. Twenty-five of 27 (93%) patients transplanted (four retransplants) for chronic HBV cirrhosis show no evidence of recurrent HBV (range, 2-55 months). Anti-HBs titers necessary to minimize the risk of hepatitis B surface antigen detectability were >500 IU/L for days 0 to 7, >250 IU/L for days 8 to 90, and >100 IU/L thereafter. Pretransplant HBV E antigen (HBeAG)-positive patients required more HBIG to achieve these goals than HBeAG-negative individuals. The elimination of anti-HBs changed continually for the initial 3 posttransplant months. The anti-HBs half-life increased from 0.7 days to 14.1 days. Anti-HBs elimination was significantly different in HBeAG+ and HBeAG- patients for the first week, but was subsequently indistinguishable after week 1. After 3 months, the half-life was statistically less for HBeAG+ patients, but the difference did not influence the clinical treatment regimens. Quantitative hepatitis B DNA levels did not predict the amount of HBIG required. HBV recurrence after orthotopic liver transplantation can be reduced by aggressive passive immunization. Pharmacokinetic analysis of anti-Hbs elimination can improve immunoglobulin therapy and prevent recurrence of clinical hepatitis.

Lymphotropism of hepatitis B and C viruses: an update and a newcomer

The mechanisms of viral persistence are complex and include infection of the lymphoid cells. In the case of hepatitis B virus, early observations have suggested that HBV may infect peripheral blood mononuclear cells (PBMC). In animal models studies in chronic hepatitis B patients have further confirmed that viral DNA replicative intermediates, as well as viral transcripts and proteins, can be detected in PBMC under certain conditions. The consequences of this lymphotropism are not fully understood, but it seems likely that PBMC represent an extrahepatic reservoir of virus. The ability of hepatitis C virus to infect PBMC has been demonstrated in vivo and in vitro. The link between HCV lymphotropism and both the natural history of the viral infection and the immunological disorders frequently observed in HCV infections still needs to be established. In both cases, the infection of PBMC by HBV or HCV may represent the source of infection of the liver graft in patients transplanted for end-stage liver disease associated with HBV or HCV.