Regulation of inflammatory response by LINC00346 via miR-25-3p-mediated modulation of the PTEN/PI3K/AKT/NF-κB pathway

Long intergenic non-coding RNA 346 (LINC00346) has been reported to be involved in the development of atherosclerosis and specific cancers by affecting signaling pathways. However, its function in inflammation has not been thoroughly studied. Therefore, its expression pattern and function were determined in the human macrophage-like cell line THP-1. Lipopolysaccharide (LPS) treatment induced the expression of LINC00346. LPS-induced NF-κB activation and proinflammatory cytokine expression were suppressed or enhanced by the overexpression or knockdown of LINC00346, respectively. Analyses using dual luciferase assay and decoy RNAs that could block RNA-RNA interactions indicated that LINC00346 improves phosphatase and tensin homolog (PTEN) expression by sponging miR-25-3p. Subsequently, PTEN suppresses phosphoinositide-3 kinase (PI3K)-mediated conversion of phosphatidylinositol-4,5-bisphosphate (PIP2) into phosphatidylinositol-3,4,5-trisphosphate (PIP3) as well as consequent activation of protein kinase B (AKT) and NF-κB. Interestingly, database analysis revealed that the expression levels of LINC00346 and PTEN were simultaneously decreased in breast cancer tissues. Further analyses conducted using a breast cancer cell line, MDA-MB-231, confirmed the functional relationship among LINC00346, miR-25-3p, and PTEN in LPS-induced activation of NF-κB. These results indicate that miR-25-3p-sponging activity of LINC00346 affects the balance between PTEN and PI3K as well as the downstream activation of AKT/NF-κB pathway in inflammatory conditions.

HSPA9 reduction exacerbates symptoms and cell death in DSS-Induced inflammatory colitis

Inflammatory bowel disease (IBD) is a chronic inflammatory condition that is influenced by various factors, including environmental factors, immune responses, and genetic elements. Among the factors that influence IBD progression, macrophages play a significant role in generating inflammatory mediators, and an increase in the number of activated macrophages contributes to cellular damage, thereby exacerbating the overall inflammatory conditions. HSPA9, a member of the heat shock protein 70 family, plays a crucial role in regulating mitochondrial processes and responding to oxidative stress. HSPA9 deficiency disrupts mitochondrial dynamics, increasing mitochondrial fission and the production of reactive oxygen species. Based on the known functions of HSPA9, we considered the possibility that HSPA9 reduction may contribute to the exacerbation of colitis and investigated its relevance. In a dextran sodium sulfate-induced colitis mouse model, the downregulated HSPA9 exacerbates colitis symptoms, including increased immune cell infiltration, elevated proinflammatory cytokines, decreased tight junctions, and altered macrophage polarization. Moreover, along with the increased mitochondrial fission, we found that the reduction in HSPA9 significantly affected the superoxide dismutase 1 levels and contributed to cellular death. These findings enhance our understanding of the intricate mechanisms underlying colitis and contribute to the development of novel therapeutic approaches for this challenging condition.

Protective Effect of GIP against Monosodium Glutamate-Induced Ferroptosis in Mouse Hippocampal HT-22 Cells through the MAPK Signaling Pathway

The effect of glucose-dependent insulinotropic polypeptide (GIP) on cells under oxidative stress induced by glutamate, a neurotransmitter, and the underlying molecular mechanisms were assessed in the present study. We found that in the pre-treatment of HT-22 cells with glutamate in a dose-dependent manner, intracellular ROS were excessively generated, and additional cell damage occurred in the form of lipid peroxidation. The neurotoxicity caused by excessive glutamate was found to be ferroptosis and not apoptosis. Other factors (GPx-4, Nrf2, Nox1 and Hspb1) involved in ferroptosis were also identified. In other words, it was confirmed that GIP increased the activity of sub-signalling molecules in the process of suppressing ferroptosis as an antioxidant and maintained a stable cell cycle even under glutamate-induced neurotoxicity. At the same time, in HT-22 cells exposed to ferroptosis as a result of excessive glutamate accumulation, GIP sustained cell viability by activating the mitogen-activated protein kinase (MAPK) signalling pathway. These results suggest that the overexpression of the GIP gene increases cell viability by regulating mechanisms related to cytotoxicity and reactive oxygen species production in hippocampal neuronal cell lines.

[6]-Gingerol Suppresses Oral Cancer Cell Growth by Inducing the Activation of AMPK and Suppressing the AKT/mTOR Signaling Pathway

BACKGROUND/AIM

[6]-Gingerol, a compound extracted from ginger, has been studied for its therapeutic potential in various types of cancers. However, its effects on oral cancer remain largely unknown. Here, we aimed to investigate the potential anticancer activity and underlying mechanisms of [6]-gingerol in oral cancer cells.

MATERIALS AND METHODS

We analyzed the antigrowth effects of [6]-gingerol in oral cancer cell lines by cell proliferation, colony formation, migration, and invasion assays. We detected cell cycle and apoptosis with flow cytometry and further explored the mechanisms of action by immunoblotting.

RESULTS

[6]-Gingerol significantly inhibited oral cancer cell growth by inducing apoptosis and cell cycle G2/M phase arrest. [6]-Gingerol also inhibited oral cancer cell migration and invasion by up-regulating E-cadherin and down-regulating N-cadherin and vimentin. Moreover, [6]-gingerol induced the activation of AMPK and suppressed the AKT/mTOR signaling pathway in YD10B and Ca9-22 cells.

CONCLUSION

[6]-Gingerol exerts anticancer activity by activating AMPK and suppressing the AKT/mTOR signaling pathway in oral cancer cells. Our findings highlight the potential of [6]-gingerol as a therapeutic drug for oral cancer treatment.

Overexpression of Lin28a Aggravates Psoriasis-Like Phenotype by Regulating the Proliferation and Differentiation of Keratinocytes

Purpose

Psoriasis is a common and well-studied autoimmune skin disease, which is characterized by plaques. The formation of psoriasis plaques occurs through the hyperproliferation and abnormal differentiation of keratinocytes, infiltration of numerous immune cells into the dermis, increased subepidermal angiogenesis, and various autoimmune-associated cytokines and chemokines. According to previous research, Lin28 regulates the let-7 family, and let-7b is associated with psoriasis. However, the link between Lin28 and psoriasis is unclear. In this study, an association was identified between Lin28a and psoriasis progression, which promoted the pathological characteristic of psoriasis in epidermal keratinocytes.

Patients and Methods

This study aims to investigate the role of Lin28a and its underlying mechanism in psoriasis through in vivo and in vitro models, which include the Lin28a-overexpressing transgenic (TG) mice and Lin28a-overexpressing human keratinocyte (HaCaT) cell lines, respectively.

Results

In vivo and in vitro results revealed that overexpression of Lin28a downregulated microRNA let-7 expression levels and caused hyperproliferation and abnormal differentiation in keratinocytes. In imiquimod (IMQ)-induced psoriasis-like inflammation, Lin28a overexpressing transgenic (TG) mice exhibited more severe symptoms of psoriasis.

Conclusion

Mechanistically, Lin28a exacerbated psoriasis-like inflammation through the activation of the extracellular-signal-regulated kinase (ERK) and signal transducer and activator of transcription 3 signaling (STAT 3) by targeting proinflammatory cytokine interleukin-6 (IL-6).

JAZF1 heterozygous knockout mice show altered adipose development and metabolism

BACKGROUND

Juxtaposed with another zinc finger protein 1 (JAZF1) is associated with metabolic disorders, including type 2 diabetes mellitus (T2DM). Several studies showed that JAZF1 and body fat mass are closely related. We attempted to elucidate the JAZF1 functions on adipose development and related metabolism using in vitro and in vivo models.

RESULTS

The JAZF1 expression was precisely regulated during adipocyte differentiation of 3T3-L1 preadipocyte and mouse embryonic fibroblasts (MEFs). Homozygous JAZF1 deletion (JAZF1-KO) resulted in impaired adipocyte differentiation in MEF. The JAZF1 role in adipocyte differentiation was demonstrated by the regulation of PPARγ-a key regulator of adipocyte differentiation. Heterozygous JAZF1 deletion (JAZF1-Het) mice fed a normal diet (ND) or a high-fat diet (HFD) had less adipose tissue mass and impaired glucose homeostasis than the control (JAZF1-Cont) mice. However, other metabolic organs, such as brown adipose tissue and liver, were negligible effect on JAZF1 deficiency.

CONCLUSION

Our findings emphasized the JAZF1 role in adipocyte differentiation and related metabolism through the heterozygous knockout mice. This study provides new insights into the JAZF1 function in adipose development and metabolism, informing strategies for treating obesity and related metabolic disorders.

Overexpression of cathepsin S exacerbates lupus pathogenesis through upregulation TLR7 and IFN-α in transgenic mice

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that affects multiple organs. Recent studies suggest relevance between cysteine protease cathepsin S (CTSS) expression and SLE. To investigate the mechanism of CTSS in SLE, CTSS-overexpressing transgenic (TG) mice were generated, and induced lupus-like symptoms. Eight months later, the TG mice spontaneously developed typical SLE symptoms regardless of the inducement. Furthermore, we observed increased toll-like receptor 7 (TLR7) expression with increased monocyte and neutrophil populations in the TG mice. In conclusion, overexpression of CTSS in mice influences TLR7 expression, autoantibodies and IFN-α, which leads to an autoimmune reaction and exacerbates lupus-like symptoms.

Costunolide Induces Apoptosis via the Reactive Oxygen Species and Protein Kinase B Pathway in Oral Cancer Cells

Oral cancer (OC) has been attracted research attention in recent years as result of its high morbidity and mortality. Costunolide (CTD) possesses potential anticancer and bioactive abilities that have been confirmed in several types of cancers. However, its effects on oral cancer remain unclear. This study investigated the potential anticancer ability and underlying mechanisms of CTD in OC in vivo and in vitro. Cell viability and anchorage-independent colony formation assays were performed to examine the antigrowth effects of CTD on OC cells; assessments for migration and invasion of OC cells were conducted by transwell; Cell cycle and apoptosis were investigated by flow cytometry and verified by immunoblotting. The results revealed that CTD suppressed the proliferation, migration and invasion of oral cancer cells effectively and induced cell cycle arrest and apoptosis; regarding the mechanism, CTD bound to AKT directly by binding assay and repressed AKT activities through kinase assay, which thereby downregulating the downstream of AKT. Furthermore, CTD remarkably promotes the generation of reactive oxygen species by flow cytometry assay, leading to cell apoptosis. Notably, CTD strongly suppresses cell-derived xenograft OC tumor growth in an in vivo mouse model. In conclusion, our results suggested that costunolide might prevent progression of OC and promise to be a novel AKT inhibitor.

LETMD1 Regulates Phagocytosis and Inflammatory Responses to Lipopolysaccharide via Reactive Oxygen Species Generation and NF-κB Activation in Macrophages

LETM1 domain-containing protein 1 (LETMD1), also known as HCCR-1, is a mitochondrial protein and is known to regulate p53 and STAT3 activities in cancer cells. In this study, we present, for the first time (to our knowledge), data indicating that LETMD1 suppresses multiple immune responses in monocyte/macrophage lineage cells and mouse primary macrophages. Attenuation of LETMD1 expression with specific small interfering RNA and short hairpin RNA constructs enhanced LPS-induced expressions of inflammatory mediators in macrophages. In addition, LETMD1 attenuation caused potentiation of phagocytosis as well as migration in a macrophage-like cell line, U937. These enhancing effects were associated with altered activation of signaling adaptors (such as NF-κB, MAPKs, p53, and JAK-STAT) involved in TLR4 signaling. Especially, LETMD1 selectively regulated TLR4-induced NF-κB activation via MyD88 but not via TIR-domain-containing adapter-inducing IFN-β (TRIF). Attenuation of LETMD1 expression caused mitochondrial hyperpolarization and subsequent decrease in ATP production and increase in mitochondrial/cellular reactive oxygen species (ROS) and intracellular calcium levels. LETMD1 attenuation also enhanced LPS-induced expression of NADPH oxidase (NOX) 2, the main producer of cellular ROS in phagocytes, through augmenting IFN regulatory factor 1. Accordingly, treatment with ROS scavenger, NOX2 suppressing agents, or calcium chelators resulted in suppression of LPS-induced cytokine production as well as NF-κB activation in cells with LETMD1 attenuation. These findings reveal a previously unknown function of LETMD1 and provide evidences showing LETMD1 negatively regulates macrophage functions by modulating mitochondrial function, subsequent ROS generation, and NF-κB activation.

Mitochondrial dysfunction regulates the JAK-STAT pathway via LKB1-mediated AMPK activation ER-stress-independent manner

Mitochondria affect cellular functions alone or in cooperation with other cellular organelles. Recent research has demonstrated the close relationship of mitochondria with the endoplasmic reticulum (ER), both at the physical and the functional level. In an effort to define the combined effect of mitochondrial dysfunction (MD) and ER stress in the proinflammatory activities of macrophages, the human macrophage-like monocytic leukemia cell line THP-1 was treated with mitochondrial electron transport chain (ETC) blockers, and changes in the cellular responses upon stimulation by interferon (IFN)-γ were analyzed. Inducing mitochondrial dysfunction (MD) with ETC blockers resulted in suppression of IFN-induced activation of JAK1 and STAT1/3, as well as the expression of STAT1-regulated genes. In addition, experiments utilizing pharmacological modulators of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and liver kinase B1 (LKB1)-deficient HeLa cells demonstrated that these suppressive effects are mediated by the LKB1-AMPK pathway. Treatment with pharmacological inhibitors of ER stress sensors failed to affect these processes, thus indicating that involvement of ER stress is not required. These results indicate that MD, induced by blocking the ETC, affects IFN-induced activation of JAK-STAT and associated inflammatory changes in THP-1 cells through the LKB1-AMPK pathway independently of ER stress.

Reverse Signaling of Tumor Necrosis Factor Superfamily Proteins in Macrophages and Microglia: Superfamily Portrait in the Neuroimmune Interface

The tumor necrosis factor (TNF) superfamily (TNFSF) is a protein superfamily of type II transmembrane proteins commonly containing the TNF homology domain. The superfamily contains more than 20 protein members, which can be released from the cell membrane by proteolytic cleavage. Members of the TNFSF function as cytokines and regulate diverse biological processes, including immune responses, proliferation, differentiation, apoptosis, and embryogenesis, by binding to TNFSF receptors. Many TNFSF proteins are also known to be responsible for the regulation of innate immunity and inflammation. Both receptor-mediated forward signaling and ligand-mediated reverse signaling play important roles in these processes. In this review, we discuss the functional expression and roles of various reverse signaling molecules and pathways of TNFSF members in macrophages and microglia in the central nervous system (CNS). A thorough understanding of the roles of TNFSF ligands and receptors in the activation of macrophages and microglia may improve the treatment of inflammatory diseases in the brain and periphery. In particular, TNFSF reverse signaling in microglia can be exploited to gain further insights into the functions of the neuroimmune interface in physiological and pathological processes in the CNS.

ER stress differentially affects pro-inflammatory changes induced by mitochondrial dysfunction in the human monocytic leukemia cell line, THP-1

The functional and physical interaction between mitochondria and the endoplasmic reticulum (ER) has been the subject of intense study. To test the effect of this interaction on macrophage inflammatory activation, the human macrophage-like monocytic leukemia cell line THP-1 was treated with oligomycin, rotenone, or sodium azide, which induce mitochondrial dysfunction (MD) by blocking the electron transport chain (ETC). MD induced by these agents triggered activation of various sensors and markers of ER stress. This linkage affected macrophage function since LPS-induced expression of IL-23 was enhanced by the MD inducers, and this enhancing effect was abolished by inhibition of pancreatic endoplasmic reticulum kinase (PERK) activity. This MD-mediated ER stress may be universal since it was observed in human embryonic kidney HEK293 cells and colon cancer SW480 cells. On the other hand, MD regulated LPS-induced activation of the AKT/GSK3β/β-catenin pathway in a manner not affected by inhibition of PERK or inositol-requiring enzyme 1α (IRE1α) activities. These results indicate that the occurrence of MD can lead to ER stress and these two events, separately or in combination, can affect various cellular processes.

Crosstalk between signals initiated from TLR4 and cell surface BAFF results in synergistic induction of proinflammatory mediators in THP-1 cells

Cellular response to stimulation is mediated by meshwork of signaling pathways that may share common signaling adaptors. Here, we present data demonstrating that signaling pathways initiated from the membrane-bound form of B-cell activating factor (BAFF) can crosstalk with lipopolysaccharide (LPS)-induced signaling for synergistic expression of proinflammatory mediators in the human macrophage-like cell line THP-1. Co-treatment of the cells with BAFF-specific monoclonal antibody and LPS resulted in enhanced mitogen-activated protein kinase (MAPK)/mitogen- and stress-activated protein kinase (MSK)-mediated phosphorylation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 subunit (Ser276), which then interacts with CREB binding protein (CBP) for subsequent acetylation. Simultaneously, the phosphorylation of cyclic AMP-response element binding protein (CREB) was enhanced through the combined action of phosphatidylinositol-3-kinase (PI3K)/AKT and MAPK/MSK pathways, and the resulting phospho-CREB interacted with the NF-κB/CBP complex. Transfection of CREB-specific siRNA inhibited the BAFF-mediated enhancing effect indicating that the formation of the CREB/NF-κB/CBP complex is required for the synergistic induction of the proinflammatory genes. These findings indicate that BAFF-mediated reverse signaling can modulate LPS-induced inflammatory activation through regulation of NF-κB and CREB activity and point out the necessity to re-evaluate the role of BAFF in diseases where its expression is high in macrophages.

Predictors of response to tenofovir disoproxil fumarate plus peginterferon alfa-2a combination therapy for chronic hepatitis B

BACKGROUND

In patients with chronic hepatitis B, tenofovir disoproxil fumarate (TDF) plus pegylated interferon (PEG-IFN) for 48-weeks results in higher rates of hepatitis B surface antigen (HBsAg) loss than either monotherapy.

AIM

To identify baseline and on-treatment factors associated with HBsAg loss at Week 72 and provide a model for predicting HBsAg loss in patients receiving combination therapy for 48 weeks.

METHODS

A secondary analysis of data from an open-label study where patients were randomised to TDF (300 mg/day, oral) plus PEG-IFN (PI, 180 μg/week, subcutaneous) for 48 weeks (TDF/PI-48w); TDF plus PEG-IFN for 16 weeks, TDF for 32 weeks (TDF/PI-16w+TDF-32w); TDF for 120 weeks (TDF-120w) or PEG-IFN for 48 weeks (PI-48w). Logistic regression methods were used to identify models that best predicted HBsAg loss at Week 72.

RESULTS

Rates of HBsAg loss at Week 72 were significantly higher in the TDF/PI-48w group (6.5%) than in the TDF/PI-16w+TDF-32w (0.5%), TDF-120w (0%) and PI-48w (2.2%) groups (P = 0.09). The only baseline factor associated with response was genotype A. HBsAg decline at Week 12 or 24 of treatment was associated with HBsAg loss at Week 72 (P < 0.001). HBsAg decline >3.5 log₁₀ IU/mL at Week 24 in the TDF/PI-48w group resulted in a positive predictive value of 85% and a negative predictive value of 99% for HBsAg loss at Week 72.

CONCLUSIONS

HBsAg decline at Week 24 of TDF plus PEG-IFN combination therapy may identify patients who, after completing 48 weeks of treatment, have a better chance of achieving HBsAg loss at Week 72.

Asian-Pacific clinical practice guidelines on the management of hepatitis B: a 2015 update

Worldwide, some 240 million people have chronic hepatitis B virus (HBV), with the highest rates of infection in Africa and Asia. Our understanding of the natural history of HBV infection and the potential for therapy of the resultant disease is continuously improving. New data have become available since the previous APASL guidelines for management of HBV infection were published in 2012. The objective of this manuscript is to update the recommendations for the optimal management of chronic HBV infection. The 2015 guidelines were developed by a panel of Asian experts chosen by the APASL. The clinical practice guidelines are based on evidence from existing publications or, if evidence was unavailable, on the experts' personal experience and opinion after deliberations. Manuscripts and abstracts of important meetings published through January 2015 have been evaluated. This guideline covers the full spectrum of care of patients infected with hepatitis B, including new terminology, natural history, screening, vaccination, counseling, diagnosis, assessment of the stage of liver disease, the indications, timing, choice and duration of single or combination of antiviral drugs, screening for HCC, management in special situations like childhood, pregnancy, coinfections, renal impairment and pre- and post-liver transplant, and policy guidelines. However, areas of uncertainty still exist, and clinicians, patients, and public health authorities must therefore continue to make choices on the basis of the evolving evidence. The final clinical practice guidelines and recommendations are presented here, along with the relevant background information.

Activation of lymphotoxin-beta receptor enhances the LPS-induced expression of IL-8 through NF-κB and IRF-1

Lymphotoxin-beta receptor (LTβR), a receptor for LIGHT and LTα1β2, is expressed on the epithelial, stromal, and myeloid cells. LTβR is known to affect the lymphoid organ development and immune homeostasis. However, its role in macrophage function has not been sufficiently elucidated. The effect of LTβR stimulation in the inflammatory activation of macrophages was investigated by treating the human macrophage-like cell line THP-1 with LTβR-specific monoclonal antibody. Interestingly, combined treatment with anti-LTβR antibody and LPS caused the synergistic induction of IL-8 expression at the transcriptional level. Analysis indicated that nuclear factor (NF)-κB activity was enhanced via the mitogen-activated protein kinase (MAPK) and glycogen synthase kinase (GSK)-3β/cAMP response element binding protein (CREB) pathways. In addition, LTβR stimulation induced the expression of interferon regulatory factor (IRF)-1, one of the major transcription factors of IL-8 gene. Down-regulation of IRF-1 expression reduced the enhancing effect caused by LTβR stimulation. This indicates that the LTβR stimulation enhances the LPS-induced expression of IL-8 via the combined action of NF-κB and IRF-1.

Resolution of adefovir-related nephrotoxicity by adefovir dose-reduction in patients with chronic hepatitis B

BACKGROUND

Chronic hepatitis B patients (CHB) treated with adefovir were followed up to evaluate nephrotoxicity and its outcome.

AIM

To assess the incidence of renal dysfunction during adefovir therapy in Asian patients and factors associated with it, and evaluate strategies to improve adefovir-related renal dysfunction and their impact on viral suppression.

METHODS

Chronic hepatitis B clinic patients from a tertiary hospital on adefovir treatment, with their clinical and laboratory parameters were extracted from the hospital electronic clinical database in an observational study design. Patients were excluded if they had liver/renal transplant, baseline renal impairment or were on dialysis. Adefovir-related renal dysfunction was defined as adefovir-related abnormal serum creatinine (ARASC) > 125 μmol/L (males), >90 μmol/L (females); adefovir-related abnormal GFR <60 mL/min; and adefovir-related increased serum creatinine >0.5 mg/dL, without other known causes of nephrotoxicity.

RESULTS

A total of 271/383 adefovir-treated patients were suitable for analysis and 33(12%) patients developed abnormal serum creatinine. Cumulative increase in proportion of patients with ARASC was 33.8% and GFR ≤60 mL/min was 38.3% by 6 years, while serum creatinine increase ≥0.5 mg/dL was 21.48% by 5 years. Using multivariate analysis, the only independent baseline predictor of ARASC was GFR ≤76.1 mL/min. Patients who had ARASC had similar levels of viral suppression to those who did not have ARASC. Those who had ARASC either continued adefovir (24%), switched therapy (24%) or had adefovir dose reduction (52%). ARASC resolved and GFR normalised in almost all patients after either switching therapy or reducing adefovir dose, with no difference between the two strategies (P = 0.737). Those with adefovir dose reduction had no significant increase in HBV DNA (P = 0.170).

CONCLUSIONS

Adefovir-related renal dysfunction occurred in a significant number of adefovir-treated patients, but reduction of the dose led to renal improvement without compromising treatment efficacy.

Cultural adaptation and validation of a questionnaire for use in hepatitis B patients

Health-related quality of life (HRQoL) is an important aspect of the overall management of hepatitis B virus (HBV) infection. The major challenge is to find a valid and reliable disease-specific HRQoL instrument designed specifically for measuring health status in hepatitis B patient. Consequently, this study was undertaken to adapt culturally the Hepatitis Quality of Life Questionnaire (HQLQ) and assess its suitability for use in English-speaking hepatitis B virus-infected (HBV) patients in Singapore. Two patient focus groups were conducted to facilitate the cultural adaptation of the HQLQ. Reliability was assessed using Cronbach's alpha coefficients and intraclass correlation coefficients. Item-to-scale correlation was assessed using Spearman's rank correlations (rho) between scale scores and their constituent items. Convergent and divergent construct validities were tested in three and two a priori hypotheses, respectively, and the correlations were assessed using Spearman's rank correlation coefficients (rho). The culturally adapted questionnaire was tested in 298 HBV patients. The test-retest reliability was supported with 10 of the 12 scales showing acceptable correlation coefficients (i.e. alpha>0.7). Item-to-scale correlations were good with most items highly correlated with their hypothesized scales. Convergent and divergent construct validities were supported by the presence of hypothesized correlations between the HQLQ and the EQ-5D domains (eight of 10 sub-hypotheses for convergent construct validity and all hypotheses for divergent construct validity were fulfilled). In conclusion, our results showed that the culturally adapted HQLQ has good validity and reliability, making it a potentially useful outcome measure in the evaluation of HBV patients in Singapore.

How big is the financial burden of hepatitis B to society? A cost-of-illness study of hepatitis B infection in Singapore

Hepatitis B virus (HBV) infection is the most common cause of chronic viral liver disease in Singapore. Nevertheless, very little data exist on the financial burden of HBV infection to the society as a whole. The aim of this study was therefore to assess the direct and indirect cost of HBV infection in a cost-of-illness analysis. The combined data from the direct and indirect cost with the estimated prevalence for different disease stages of HBV infection would represent the annual financial burden of HBV infection to the Singaporean society as a whole. The estimated total annual cost of chronic HBV infection and its associated complications in Singapore was US$279 million (range US$34-941 million when allowing various assumptions as tested by the sensitivity analyses), with 58% or US$161 million attributable to direct cost. Based on the base-case estimation, total direct cost alone is equivalent to 12% of the national healthcare expenditure for 2003. The total cost incurred by chronic hepatitis B patients represents the biggest cost component, followed by decompensated cirrhosis (DC) patients. The ratio of direct to indirect costs based on the base-case estimation increased with disease severity, with the highest ratio obtained for the post-liver transplants (40.2:1), followed by hepatocellular carcinoma (7.4:1) and DC patients (2.7:1). The results of this study suggest that the management of HBV infection poses more than a medical challenge as it is a sizeable economic burden from both the payer and societal perspectives.

Zidovudine treatment for anti-HIV positive haemophiliacs

Twenty haemophiliacs (17 CDC group IV and 3 CDC group II) were treated with zidovudine for a median of 37 weeks (range 10-66). Eight (40%) tolerated zidovudine without a dose change. Two patients died and five patients (29%) developed opportunist infections. Haematological toxicity occurred in ten CDC IV patients (59%) but only one case of sepsis occurred in 101 episodes of documented granulocytopenia. Thrombocytopenia responded to treatment with zidovudine in four of five patients. It is concluded that zidovudine is beneficial for symptomatic haemophiliacs and although the haematological toxicity is high, it is mostly asymptomatic, reversible and well tolerated. Two of the three CDC II patients treated with zidovudine progressed to CDC IV, but had low initial T4 lymphocyte counts and were P24 antigen positive.

Antibodies to platelet glycoproteins in haemophiliacs infected with HIV

The techniques of Western blotting and the monoclonal antibody specific immobilization of platelet antigen (MAIPA) assay were used to detect antibodies to platelet glycoproteins in 43 samples of serum from 23 anti-HIV positive haemophiliacs (8 with severe thrombocytopenia, 6 with moderate thrombocytopenia, and 9 with a normal platelet count), six anti-HIV negative haemophiliacs and ten controls. Antibodies were present in the majority of anti-HIV positive patients' sera even before the onset of thrombocytopenia. Thrombocytopenia was associated with an increase in the incidence of antibodies to GPIIIa and GPIb, whereas the antigen most frequently recognized in patients without thrombocytopenia was GPIIb. Anti-GPIIb and/or GPIIIa reactivity was also seen in three out of the six anti-HIV negative patients. There was no correlation between the absolute platelet count and the detection of antibodies in either assay. Effective therapy for thrombocytopenia with zidovudine, interferon or splenectomy did not influence the presence of antibody. Eight of nine patients with AIDS were negative in the MAIPA assay, consistent with their depressed immune status. It is concluded that the production of antibodies to platelet membrane glycoprotein in anti-HIV positive haemophiliacs is influenced by factors other than HIV. The presence of such antibodies is independent of the platelet count and is therefore unlikely to play a causative role in HIV-related thrombocytopenia.

The treatment of HIV associated thrombocytopenia in haemophiliacs

HIV associated thrombocytopenia occurs in 5-10% of asymptomatic individuals, and 25-45% of people with AIDS. A variety of treatments are available but the inherited bleeding disorder in addition to the thrombocytopenia makes management in haemophiliacs a special problem. The management of this double coagulopathy is described in seven patients. IV gammaglobulin and steroids were useful only in the short term; zidovudine produced a good response, could be taken orally, had anti-HIV activity and was well tolerated in asymptomatic HIV positive patients. Interferon was an alternative when zidovudine was ineffective or produced intolerable side-effects. Splenectomy was considered only after failure of other treatments because of the increased risks of bleeding.

Clinical trial: a phase II, randomized study evaluating the safety, pharmacokinetics and anti-viral activity of clevudine for 12 weeks in patients with chronic hepatitis B

BACKGROUND

Clevudine is a polymerase inhibitor that has the unusual feature of delayed viral rebound after therapy in some patients which may be related to its pharmacokinetics.

AIM

To characterize pharmacokinetic and pharmacodynamic profile of clevudine, a potent hepatitis B polymerase inhibitor.

METHODS

A multicenter, randomized study comparing 10, 30 and 50 mg clevudine once daily for 12 weeks with 24 weeks off-treatment follow-up. Patients had chronic HBV infection, were nucleoside-naïve without co-infection. HBV viral load (VL) was assayed using Digene Hybrid Capture II with a lower limit of detection of 4700 copies/mL (940 IU/mL). Clevudine levels were measured using a liquid chromatography/mass spectrometery method.

RESULTS

A total of 31 patients were enrolled into the 10 mg (n = 10), 30 mg (n = 11) and 50 mg (n = 10) groups, respectively. At week 12, the median VL change was -3.2, -3.7 and -4.2 log(10) copies/mL (-0.64, -0.74 and -0.84 log(10) IU/mL) in the 10, 30 and 50 mg groups, respectively (P = 0.012). At week 12, one of 10, five of 11 and two of 10 patients had VL below the assay lower limit of detection. Clevudine was well tolerated with no severe/serious adverse events. The mean plasma half-life of clevudine was 70 h and consequently is not the cause of the delayed viral rebound seen in some patients. Through modelling, 97% of the maximal treatment effect was reached with a 30 mg daily dose. Six patients had genomic changes without viral rebound.

CONCLUSION

Clevudine appears to be a potent and tolerable (over 12 weeks) anti-viral and the optimal dosage appears to be 30 mg once daily.

Clinical trial: effects of adefovir dipivoxil therapy in Asian and Caucasian patients with chronic hepatitis B

BACKGROUND

Two-thirds of the 350 million people infected with chronic hepatitis B virus live in the Asia-Pacific region. AIM To compare the effects of adefovir dipivoxil therapy between Asian and Caucasian patients with chronic hepatitis B.

METHODS

The safety and efficacy of 10 mg of adefovir dipivoxil was compared to placebo in 501 Asian (n = 259) or Caucasian (n = 242) HBeAg+ and HBeAg- chronic hepatitis B virus patients treated for 48 weeks in two randomized, double-blind, placebo-controlled studies.

RESULTS

At week 48, histological improvement was observed in 60% and 56% of Caucasian and Asian patients, respectively. Change in serum hepatitis B virus DNA from baseline to week 48 for the adefovir dipivoxil-treated patients was -3.89 and -3.70 log(10) copies/mL in Caucasian and Asian patients, respectively, while 34 per cent of Caucasian patients and 39 per cent of Asian patients had undetectable serum hepatitis B virus DNA (<400 copies/mL) at week 48. The percentage of patients achieving alanine aminotransferase (ALT) normalization at week 48 was similar in both groups (Caucasian 64 per cent, Asian 63 per cent). No patients developed resistance through week 48. No differences in adverse events or grade 3 or 4 laboratory abnormalities were observed between groups.

CONCLUSIONS

There were no significant differences in treatment response between Asians and Caucasians. Adefovir dipivoxil was well tolerated and no resistance developed up to week 48 in both racial groups.

Liver transplantation for hepatocellular carcinoma in Singapore

INTRODUCTION

The prognosis of patients with hepatocellular carcinoma (HCC) is poor. Surgical resection offers the benefit of removal of the tumour but is associated with liver decompensation and tumour recurrence, even after successful surgery. Liver transplantation offers the benefits of complete tumour removal with prevention of both decompensation and recurrence post-operation. This paper aims to review results of liver transplantation for patients with HCC in Singapore.

METHODS

All adult patients with HCC accepted on the waiting list for liver transplantation (based on the Milan criteria) from 1996 to 2004 in Singapore were reviewed. Patients' HCC were managed with either transarterial chemoembolisation or percutaneous radiofrequency ablation while they were on the waiting list. Post-transplant survival and factors associated with mortality were analysed by Cox regression analysis.

RESULTS

41 patients with HCC were accepted onto the waiting list over the nine-year period. 22 underwent transplantation and 19 did not, with a one-year survival of 91 percent versus 24 percent, respectively. (p-value is less than 0.001). Mean waiting time for transplant was 39 weeks. Post-transplant HCC recurrence was 2/22 (nine percent). Among all patients, mortality was significantly related to baseline white cell counts, prothrombin time, age, alpha-foetoprotein level, Child-Pugh score, and whether patients underwent transplant.

CONCLUSION

Despite the relatively long waiting time of a mean of 39 weeks, post-transplant recurrence of HCC was relatively low at nine percent. Liver transplant is an effective treatment for patients with a HCC, with a reasonable long-term survival.

Referral patterns and waiting times for liver transplantation in Singapore

INTRODUCTION

Referral patterns, waiting times, waiting list, and mortality provide information on how effectively a transplant programme deals with referred patients. This paper aims to review these parameters in the Singapore National Liver Transplant Programme.

METHODS

Data of all patients referred to the Singapore National Liver Transplant Programme since its inception were captured and outcomes were retrieved and described.

RESULTS

562 patients were referred for liver transplant evaluation from 1990-2004, consisting of 457 adults and 105 children. The main indications for referral were hepatitis B liver disease and hepatocellular carcinoma in adults, and biliary atresia in children. Most patients were of United Network of Organ Sharing (UNOS) status 3 or 4 at the time of referral. 114 (20.28 percent) patients had transplants, consisting of 66 adults (14.44 percent) and 48 (45.71 percent) children. 138 adults and ten children were rejected for transplant, mainly for the reason of being "too early". The median waiting time for adults who had transplants was 3.3 months while adults still on the waiting list had been waiting for 16.2 months. The overall waiting list mortality was 44.3 percent, being 52.5 percent in adults and 23.2 percent in children.

CONCLUSION

The overall transplantation rate is low and the waiting list mortality is high as a result of low availability of organs, particularly in adults. Paediatric liver transplant appears to have been better at dealing with referred patients but this is probably due to availability of living-related liver transplant. Improvement in these may result from the Human Organ Transplant Act.

Long-term post-liver transplant complications of renal impairment and diabetes mellitus: data from Singapore

INTRODUCTION

Patients who survive the initial post-liver transplantation period face the development of chronic diseases in the long run. We studied two important complications of liver transplantation, namely: renal impairment and diabetes mellitus.

METHODS

We analysed adult patients followed-up for more than one year using data from our liver transplant clinical records. Long-term post-transplant renal impairment (RI) was defined as glomerular filtration rate (GFR) less than 60 ml/min/1.73 square metres and long-term post-transplant diabetes mellitus (DM) was defined as fasting blood glucose more than 7.8 mmol/L, that existed at least one year after liver transplantation. Pre- and post-transplant factors that could be associated with these conditions were examined.

RESULTS

Altogether, 35 patients were evaluated. Mean age at transplant was 50 years. Mean duration of follow-up was 58.4 months. There was 11.4 percent of pre-transplant RI and 17.0 percent of pre-transplant DM. Prevalence of post-transplant RI was 43.5 percent at one year and 45.0 percent at four years. Long-term post-transplant RI was associated with renal impairment at six months post-transplant (p-value is 0.033). Prevalence of severe post-transplant RI (GFR is less than 30 ml/min/1.73 square metres) at four years was 5.7 percent. Prevalence of post-transplant DM was 45.5 percent at two years but declined to 5.3 percent at four years.

CONCLUSION

Post-transplant renal impairment appears to be a potential long-term problem while post-transplant diabetes mellitus appears to improve with time.

MELD may not be the better system for organ allocation in liver transplantation patients in Singapore

INTRODUCTION

The Model for End-Stage Liver Disease (MELD) score is a good predictor of mortality on the liver transplant waiting list and is the current system of organ allocation in the USA. However, a higher MELD may be associated with poorer outcome post-liver transplantation. The aim of this study was to determine if MELD should be implemented as the system for organ allocation for liver transplantation in Singapore.

METHODS

There were 46 adult patients who underwent primary liver transplantation at the National University Hospital, Singapore from January 1996 to December 2002. We applied the MELD score to patients who were transplanted and looked for a correlation with survival post-transplant. Patients were followed-up until the most recent visit or death. Survival analysis was performed using Cox regression and Kaplan-Meier method.

RESULTS

The mean age at transplant was 52.7 (SD 2.34) years. The majority of the patients transplanted had Hepatitis B (43 percent). The median MELD score at transplantation was 17 (7-42) and the median Child's score was 11 (6-15). There was a significant correlation between pre-transplant MELD and survival at six months (p-value is 0.037, 95 percent confidence interval [CI] is 1.004-1.13) but not at one year (p-value is 0.065, 95 percent CI is 0.99-1.12). There were no differences in the pre-transplant MELD (odds-ratio [OR] 1, 95 percent CI 0.9-1) as well as survival for patients with and without Hepatitis B (OR 0.72, 95 percent CI 0.22-2.35).

CONCLUSION

MELD allows livers to be allocated to the patients with the greatest medical urgency but its influence on post-transplant survival should be further clarified so that post-transplant survival is not compromised.

Liver transplantation in Singapore 1990-2004

INTRODUCTION

Liver transplantation is the accepted standard of care for patients with hepatocellular carcinoma, decompensated liver cirrhosis, and acute liver failure. Since the first liver transplant done in Singapore in 1990, results have been improving. We review the overall results of liver transplantation over the last 15 years.

METHODS

All transplant cases from 1990 to 2004 were reviewed retrospectively.

RESULTS

100 liver transplants were performed over the last 15 years; four in the first five years and 96 in the subsequent ten years. Overall one- and five-year survival rates were 80 percent and 78 percent, respectively. 44 were paediatric transplants, of which biliary atresia was the commonest indication for paediatric transplant. 56 were adult transplants of which hepatocellular carcinoma and decompensated hepatitis B cirrhosis were the commonest indications for adult transplant. Infection remained the commonest cause of mortality.

CONCLUSION

The number of transplants carried out per year was small due to the low cadaveric donation rate, but the survival of liver transplant patients was comparable to well-established liver transplant centres.

Long-term results of liver transplant in patients with chronic viral hepatitis-related liver disease in Singapore

INTRODUCTION

Liver disease from chronic hepatitis B (CHB) and C (CHC) constitutes 57 percent of adult liver transplant in Singapore. Their long-term results post-transplant may be affected by recurrence of the viral illness. This study aims to evaluate the long-term results and survival in patients transplanted for CHB- and CHC-related liver disease.

METHODS

Patients transplanted for CHB- and CHC-related disease from 1990 until March 2004, which included decompensated cirrhosis and hepatocellular carcinoma (HCC), were reviewed and analysed.

RESULTS

25 patients were transplanted for CHB-related liver disease, with mean follow-up of 153 +/- 25 weeks. Two- and four-year survival rates were 75 percent and 69 percent, respectively. Hepatitis B recurrence from YMDD mutants occurred in five patients, and four were treated successfully with adefovir dipivoxil, with resolution in transaminases and/or improvement in histology. One patient became non-compliant with follow-up and medications, and died 173 weeks post-transplant from reactivation of the wild-type hepatitis B virus. Nine patients were transplanted for CHC-related liver disease, with mean follow-up of 188 +/- 40 weeks, and two- and four-year survival rates of 89 percent and 76 percent, respectively. Two patients developed hepatitis C recurrence and were treated with interferon and ribavarin. One responded with sustained response but the other remained viraemic and died of HCC recurrence two years post-transplant.

CONCLUSION

Long-term results from CHB- and CHC-related liver diseases were satisfactory and comparable to major transplant centres in the USA and Europe. Recurrence of viral hepatitis post-transplant is controllable with current antiviral therapy.

Treatment of steroid-resistant acute liver transplant rejection with basiliximab

Current rescue therapies for acute steroid-resistant rejection, such as OKT3 and high-dose tacrolimus, are not uncommonly associated with side effects that contribute to significant morbidity of the patient. Basiliximab is a chimeric monoclonal antibody that acts as an interleukin-2 receptor antagonist on the surface of activated T lymphocytes. It has until now only been used as immunoprophylaxis in adult liver transplant patients. In this report, we describe the use of Basiliximab as rescue therapy in a case of acute steroid-resistant rejection in an adult living related liver transplant recipient.

Successful listing of patients for liver transplant was related to participation of referring doctor in the transplant program

INTRODUCTION

Experience with liver transplantation is limited in many parts of Asia. Therefore, patients from nontransplant centers may not be referred in a timely fashion for transplants. Our aim was to evaluate the pattern of referral for liver transplantation and their outcomes in Singapore.

METHODS

Consecutive patients referred from 1990 to 2001 were reviewed. Patients from any hospital in Singapore (or the region) could be referred to the program. They were discussed at the weekly meetings. Appropriate patients were placed on the waiting list. "Pending" indicated that the disease was early or there were unsettled medical or social issues. Unsuitable patients were "rejected" for transplant.

RESULTS

There were 385 patients referred over a 12-year period. Hepatitis B cirrhosis and hepatocellular carcinoma (HCC) were the most common indications among adults, whereas biliary atresia was the most common for children. Pediatric patients were more likely than adult patients to be listed for transplant (53/76 vs 106/309, P < .001). Patients referred by regular attendees of the program were more likely to be accepted than nonattendees (38% vs 25%, P = .04). "Disease too early", "advanced HCC", and "refusal by family members" were the most common reasons for rejection.

CONCLUSION

Members of the Liver Transplant Program were more likely to refer suitable patients for transplant at the appropriate time. Better interaction between gastroenterologists inside and outside the transplant program would help to improve the timing of referrals for liver transplantation, and hence, patient survival.

The MELD score may help to determine optimum time for liver transplantation

BACKGROUND

The model for end-stage liver disease (MELD) score is a good predictor of mortality on the waiting list and short-term survival post liver transplantation.

AIM

Our aim was to determine if there is a pretransplant MELD score beyond which liver transplantation is prohibitive.

PATIENTS AND METHODS

Forty-six adult patients underwent primary liver transplantation from January 1996 to December 2002. Patients followed to the most recent visit or death underwent survival analysis using Cox regression and Kaplan Meier methods.

RESULTS

There was a significant correlation between the pretransplant MELD score and survival at 6 months posttransplant (P=.037 95% CI: 1.004-1.13). Patients with pretransplant MELD score greater than or equal to 32 showed significantly greater mortality compared with those less than 32 (HR 9.18, 95%CI=1.16-72.44).

CONCLUSION

Pretransplant MELD may help to determine the optimum time for liver transplantation.

The majority of hepatitis B carriers are not on regular surveillance in Singapore

INTRODUCTION

Carriers of hepatitis B virus (HBV) are at risk of developing long-term complications. Regular surveillance helps detect treatable chronic hepatitis, cirrhosis and liver cancer, and is recommended by practice guidelines in the United States, Europe and Singapore. However, there have been few studies evaluating the follow-up of HBV carriers. This study seeks to determine the proportion of HBV carriers on regular follow-up in Singapore and the impact on hepatitis B disease.

METHODS

An advertisement was taken in local newspapers advertising for free screening to HBV carriers. 387 persons answered the advertisement. The screening comprised history-taking, physical examination, blood tests (liver panel, alphafoetoprotein, hepatitis B surface antigen (Ag) and hepatitis B eAg) and ultrasonography of liver. Further evaluation was conducted if the screening results were abnormal.

RESULTS

Of the 387 HBV carriers, 346 (89 percent) were male and 375 (97 percent) were Chinese. Their mean age was 39 years (range 20-60 years) and 36 percent were positive for HBeAg. 247 (64 percent) were not on regular screening over the past 12 months. 19 (5.4 percent) patients were diagnosed to have complications, namely: 13 had HBeAg-positive chronic hepatitis, two had HBeAg-negative chronic hepatitis, one had early liver cancer who recovered well after a curative resection and three had compensated cirrhosis.

CONCLUSION

Our screening programme diagnosed 5.4 percent of complications among 387 asymptomatic HBV carriers. However, 64 percent of the study subjects were not screened regularly and may pose an important public health threat if they develop long-term complications. Further studies are needed to evaluate and improve patient compliance for screening.

Genome-wide expression profiling of RNA interference of hepatitis B virus gene expression and replication

Small interfering RNA (siRNA) has been used repeatedly to down-regulate viral gene expression and inhibit viral replication in mammalian cells. In this study, we showed that siRNAs specific for two conserved regions within the hepatitis B S antigen (HBsAg) gene can inhibit antigen production in two human liver cell lines which constitutively produce and secrete HBsAg. The inhibitory effect was concentration dependent for both PLC/PRF/5 and 2.2.15 cells. Decreases in the corresponding viral transcript levels were observed. The inhibitory effect was observed within 24 h and was still evident 7 days after the initial treatment with siRNA. A significant reduction in virion production was also observed for the 2.2.15 cells. A critical consideration in this study was the specificity of the siRNA-mediated inhibition. To address this, we first examined the effects on cell growth and viability. These were not affected in either cell line. cDNA microarrays were also used to examine genome-wide changes in gene regulation. No significant off-target gene regulation was observed in either cell line. Our findings thus indicate that siRNA can specifically mediate the down-regulation of viral gene expression leading to a reduction in virion production.

Successful treatment of Xylohypha bantiana brain abscess mimicking invasive cerebral aspergillosis in a liver transplant recipient

Invasive aspergillosis is a highly lethal disease in immunocompromised hosts especially with central nervous system involvement. In a review of 2380 liver transplants performed over 14 years, 13 out of 15 fungal brain abscesses were due to Aspergillus species and only one patient survived [Arch Surg, 132 (1997) 304]. Dematiaceous fungi while less readily recognised, often have a more favorable outcome [Transplantation, 63 (1997) 160]. We report a Xylophypha bantiana cerebral abscess in a liver transplant recipient initially identified as a branching mould on histology that had a successful outcome due to aggressive appropriate treatment.

Prophylactic lamivudine prevents hepatitis B reactivation in chemotherapy patients

BACKGROUND

Chronic hepatitis B virus carriers receiving chemotherapy develop a high hepatitis B virus reactivation rate (38-53%) with a high mortality (37-60%). Few studies have characterized the efficacy of lamivudine in the treatment of chemotherapy-induced hepatitis B virus reactivation.

AIM

To determine whether lamivudine prophylaxis reduces chemotherapy-induced hepatitis B virus reactivation and mortality.

METHODS

The medical records of all hepatitis B surface antigen-positive patients with malignancy treated with chemotherapy since 1995 at the National University Hospital of Singapore were identified, and divided into those who received lamivudine prophylaxis before chemotherapy (P) and those who did not (NP). The parameters examined included gender, age, malignancy type, steroid usage, number of chemotherapy courses and regimens, follow-up duration and hepatitis B virus status. The outcome measures were hepatitis B virus reactivation (abrupt rise of serum alanine aminotransferase to > 200 IU/L) and reactivation death. Patients with primary hepatoma or liver metastasis were excluded.

RESULTS

Thirty-five patients were identified: 16 in the P group and 19 in the NP group. The baseline characteristics of the two groups were similar. Seven of the 19 patients in the NP group and none of the 16 patients in the P group developed reactivation (36.8% vs. 0%, P=0.009). Six of the seven patients in the NP group who developed reactivation received lamivudine at that time, but five died (mortality, 71.4%), whilst no patient in the P group died from reactivation (P=0.064).

CONCLUSIONS

Prophylactic lamivudine appears to prevent hepatitis B virus reactivation and its associated mortality in patients treated with chemotherapy. This should be confirmed with prospective studies.

Fatal hepatitis B reactivation following discontinuation of nucleoside analogues for chronic hepatitis B

BACKGROUND

Nucleoside analogues such as lamivudine for chronic hepatitis B have an excellent safety profile while patients are on therapy but reactivation flares occur in 19-50% of patients after stopping therapy, some of whom develop liver decompensation.

AIMS

To describe and report three cases who developed fatal hepatitis B reactivation after stopping nucleoside analogue therapy.

SUBJECTS AND RESULTS

Three patients are described who developed hepatitis B reactivation and liver decompensation after stopping therapy. One of the three patients was participating in a famciclovir trial and the other two were receiving lamivudine therapy for active hepatitis B infection. All three patients had documented hepatitis B flares, and all had hepatitis B virus DNA detected at that time. All patients developed decompensated liver disease despite one patient having had a prior liver biopsy showing absence of cirrhosis. Reintroduction of lamivudine therapy failed to halt progression of liver decompensation even after hepatitis B virus DNA had been demonstrated to be absent. Sequencing for lamivudine resistant mutants in two cases where serum was available failed to show evidence of mutations associated with lamivudine resistance.

CONCLUSION

Hepatitis B virus reactivation, leading to decompensation and death, are possible complications of treatment withdrawal and patients should be monitored closely if therapy is ceased.

Identification and molecular characterisation of the complete genome of a Singapore isolate of hepatitis C virus: sequence comparison with other strains and phylogenetic analysis

The complete genomic sequence of a Singapore isolate of the hepatitis C virus (HCV) was obtained from serum of an individual chronically infected with HCV. Nine overlapping cDNA clones covering the entire viral genome was amplified by reverse-transcription-polymerase chain reaction (RT-PCR), This isolate (HCV-S1) comprised 9,609 nucleotides (nt), including 341 nt of the complete 5' untranslated region (5' UTR), a single open reading frame of 3,011 amino acids (aa) and 235 nt of the complete 3' UTR. Its genotype was identified as type lb from analyses of its sequences in the 5' UTR, NS3 and NS5B regions. When compared against nine reported HCV isolates, the overall aa homology of HCV-SI was closest with an Australian strain, HCV-A (94%) and a Japanese strain, HCV-JT (93.9%). Phylogenetic analysis revealed that it was most closely related to the Taiwan strain, HCV-TW and another Japanese strain, HCV-K1-R1.

The hepatitis C virus core protein interacts with NS5A and activates its caspase-mediated proteolytic cleavage

Viral proteins interact with one another during viral replication, assembly, and maturation. Systematic interaction assays of the hepatitis C virus (HCV) proteins using the yeast two-hybrid method have uncovered a novel interaction between core and NS5A. This interaction was confirmed by in vitro binding assays, and coimmunoprecipitation in mammalian cells. Core and NS5A are also colocalized in COS-7 cells. Interestingly, NS5A is cleaved to give specific-size fragments, when core is coexpressed in mammalian cells. Overexpression of core produced many dying and rounded cells and effects such as DNA laddering and the truncation of poly(ADP-ribose) polymerase 1 (PARP1), both indicators of apoptosis. These observations led us to investigate the link between the induction of apoptosis by core and the cleavage of NS5A. The proteolysis of NS5A and these apoptotic events can be inhibited by caspase inhibitor, Z-VAD, indicating that core induces apoptosis and the cleavage of NS5A by caspases. In cells infected by the HCV, core may provide the intrinsic apoptotic signal, which produces truncated forms of NS5A. The biological function of core-NS5A interaction and the downstream effect of NS5A cleavage are discussed.

Extended lamivudine treatment in patients with chronic hepatitis B enhances hepatitis B e antigen seroconversion rates: results after 3 years of therapy

A study in Chinese patients with chronic hepatitis B showed that treatment with lamivudine for 1 year significantly improves liver histology and enhances hepatitis B e antigen (HBeAg) seroconversion compared with placebo. Fifty-eight patients from this 1-year study have received long-term treatment with lamivudine 100 mg; the outcome of 3 years of lamivudine is reported here. Before treatment, all patients had detectable HBeAg. HBeAg seroconversion (HBeAg-negative, anti-HBe-positive), hepatitis B virus (HBV)-DNA suppression, alanine transaminase (ALT) normalization, emergence of YMDD variant HBV, liver histology, and long-term safety were assessed. After 3 years of continuous treatment with lamivudine 100 mg daily, 40% (23 of 58) of patients achieved HBeAg seroconversion. In patients with baseline serum ALT >2 x upper limit of normal (ULN), the rate of HBeAg seroconversion was 65% (17 of 26). Median serum HBV-DNA concentrations were below the level of detection, and median ALT concentrations were within the normal range throughout 3 years of treatment. YMDD variant HBV emerged in 33 of 58 (57%) patients during the 3 years, of whom 9 (27%) achieved HBeAg seroconversion (6 after emergence of YMDD variant HBV). ALT levels and histologic scores after emergence of YMDD variant HBV did not show major deterioration. Lamivudine was well tolerated during 3 years of therapy. In conclusion, these data in Chinese patients with chronic hepatitis B show enhanced seroconversion rates with extended lamivudine treatment. Up to two thirds of patients with moderately elevated pretreatment ALT achieved HBeAg seroconversion after 3 years of therapy.

Palliation of malignant gastric outlet obstruction caused by gastric cancer with self-expandable metal stents

Gastric carcinoma is among the most common cancers worldwide. Surgery remains the mainstay of potentially curative treatments. Unfortunately, most patients have an advanced form of the disease. We evaluated our experience in palliating malignant gastric outlet obstruction caused by gastric cancer with expandable metal stents (Wallstent Enteral; Boston Scientific, Singapore). Six patients with a median age of 68 years (range, 45-88) underwent the procedure. Three had metastatic gastric cancer; two recurrent gastric cancer; and one locally advanced gastric cancer with poor comorbid status. After the procedure, five of the six patients were able to resume an oral feeding within 24 hours. One patient with gastric dysmotility caused by linitus plastica required nasogastric tube feeding. Three patients died during a median follow-up period of 4 weeks (range, 2-8). The other three patients were still well at a median follow-up period of 10 weeks (range, 5-12). There was no procedure-related mortality or morbidity, nor was there any stent migration or blockage in any of these patients. In conclusion, palliation of malignant gastric outlet strictures caused by gastric cancer with expandable metal stents is an effective and safe alternative to surgery, particularly in patients with postgastrectomy anastomotic recurrence and in those who are poor candidates for surgery. Patients who are not expected to survive beyond 1 month and those with linitus plastica and associated gastric dysmotility may not be appropriate candidates for such a procedure.