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Mousavere I, Kalampokis G, Fousekis F, Karayiannis P, Baltayiannis G, Christodoulou D. An overview of recent treatment options for primary sclerosing cholangitis. Ann Gastroenterol 2023; 36:589-598. [PMID: 38023975 PMCID: PMC10662072 DOI: 10.20524/aog.2023.0834] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 09/26/2023] [Indexed: 12/01/2023] Open
Abstract
Primary sclerosing cholangitis (PSC) is a chronic hepatic dysfunction characterized by inflammatory and tissue-degenerative strictures of the biliary tree, leading to cirrhosis and cholangiocarcinoma. The pathophysiological mechanisms involve immune-mediated responses. Numerous treatment modalities targeting the inflammatory aspects have been suggested, but a consensus on the best treatment option is lacking. This study aims to review the most up-to-date treatment options for PSC.
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Thursz M, Sadiq F, Tree JA, Karayiannis P, Beasley DWC, Dejnirattisai W, Mongkolsapaya J, Screaton G, Wand M, Elmore MJ, Carroll MW, Matthews I, Thomas H. Corrigendum: Inhibition of phosphodiesterase 12 results in antiviral activity against several RNA viruses including SARS-CoV-2. J Gen Virol 2023; 104. [PMID: 37493135 DOI: 10.1099/jgv.0.001876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023] Open
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Thursz M, Sadiq F, Tree JA, Karayiannis P, Beasley DWC, Dejnirattisai W, Mongkolsapaya J, Screaton G, Wand M, Elmore MJ, Carroll MW, Matthews I, Thomas H. Inhibition of phosphodiesterase 12 results in antiviral activity against several RNA viruses including SARS-CoV-2. J Gen Virol 2023; 104. [PMID: 37432877 DOI: 10.1099/jgv.0.001865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023] Open
Abstract
The 2',5'- oligoadenylate synthetase (OAS) - ribonuclease L (RNAseL) - phosphodiesterase 12 (PDE12) pathway is an essential interferon-induced effector mechanism against RNA virus infection. Inhibition of PDE12 leads to selective amplification of RNAseL activity in infected cells. We aimed to investigate PDE12 as a potential pan-RNA virus antiviral drug target and develop PDE12 inhibitors that elicit antiviral activity against a range of viruses. A library of 18 000 small molecules was screened for PDE12 inhibitor activity using a fluorescent probe specific for PDE12. The lead compounds (CO-17 or CO-63) were tested in cell-based antiviral assays using encephalomyocarditis virus (EMCV), hepatitis C virus (HCV), dengue virus (DENV), West Nile virus (WNV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in vitro. Cross reactivity of PDE12 inhibitors with other PDEs and in vivo toxicity were measured. In EMCV assays, CO-17 potentiated the effect of IFNα by 3 log10. The compounds were selective for PDE12 when tested against a panel of other PDEs and non-toxic at up to 42 mg kg-1 in rats in vivo. Thus, we have identified PDE12 inhibitors (CO-17 and CO-63), and established the principle that inhibitors of PDE12 have antiviral properties. Early studies suggest these PDE12 inhibitors are well tolerated at the therapeutic range, and reduce viral load in studies of DENV, HCV, WNV and SARS-CoV-2 in human cells and WNV in a mouse model.
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Cuschieri S, Hatziyianni A, Karayiannis P, Haagsma JA, Wyper GMA, Kantaris M, Theodorou M, Pallari E. Re-engineering the Cypriot General Healthcare System for Syndemics. Front Public Health 2022; 10:734796. [PMID: 35899154 PMCID: PMC9309491 DOI: 10.3389/fpubh.2022.734796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 06/08/2022] [Indexed: 11/13/2022] Open
Abstract
To date in Cyprus, there is no dedicated “Quality Improvement” body or Public Health authority. The long-awaited general healthcare system (known as GeSy or GHS) has been completed, mid-stream of the COVID-19 pandemic. A recently proposed resilience plan in response to the lessons learnt from the pandemic was put forward by the Government of the Republic of Cyprus to strengthen the capacity of the GHS and support public health defense. The negotiator of GeSy and Health Minister 2015–2018 also provided his view that the health system needs a holistic transformation of service provision. Recognizing failures and thinking from a syndemogenesis perspective how the envisioned patient-centric healthcare delivery can be achieved, we propose that the public health response could also be linked to a politico-economic one in shielding GeSy. We make such case for a syndemic strategy (simultaneous management of COVID-19 and pre-existing epidemics on the island) and the development of the five-district model where each main district hospital is to complement the activities of the GHS through developing: 1. A training Center for training and sharing of best practices for COVID-19 and other public emergencies. 2. A public health body. 3. A quality improvement institute. 4. A commissioning center on planning and streamlining healthcare services. 5. A clinical trial platform. The rationale is based on the management literature and use of existing resources and capabilities for transforming the GeSy and generating value.
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Mamais I, Malatras A, Papagregoriou G, Giallourou N, Kakouri AC, Karayiannis P, Koliou M, Christaki E, Nikolopoulos GK, Deltas C. Circulating IgG Levels in SARS-CoV-2 Convalescent Individuals in Cyprus. J Clin Med 2021; 10:jcm10245882. [PMID: 34945178 PMCID: PMC8708243 DOI: 10.3390/jcm10245882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 12/14/2022] Open
Abstract
Long-term persistence and the heterogeneity of humoral response to SARS-CoV-2 have not yet been thoroughly investigated. The aim of this work is to study the production of circulating immunoglobulin class G (IgG) antibodies against SARS-CoV-2 in individuals with past infection in Cyprus. Individuals of the general population, with or without previous SARS-CoV-2 infection, were invited to visit the Biobank at the Center of Excellence in Biobanking and Biomedical Research of the University of Cyprus. Serum IgG antibodies were measured using the SARS-CoV-2 IgG and the SARS-CoV-2 IgG II Quant assays of Abbott Laboratories. Antibody responses to SARS-CoV-2 were also evaluated against participants’ demographic and clinical data. All statistical analyses were conducted in Stata 16. The median levels of receptor binding domain (RBD)-specific IgG in 969 unvaccinated individuals, who were reportedly infected between November 2020 and September 2021, were 432.1 arbitrary units (AI)/mL (interquartile range—IQR: 182.4–1147.3). Higher antibody levels were observed in older participants, males, and those who reportedly developed symptoms or were hospitalized. The RBD-specific IgG levels peaked at three months post symptom onset and subsequently decreased up to month six, with a slower decay thereafter. IgG response to the RBD of SARS-CoV-2 is bi-phasic with considerable titer variability. Levels of IgG are significantly associated with several parameters, including age, gender, and severity of symptoms.
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Dale JM, Hood SP, Bowen O, Bright H, Cutler KL, Berry N, Almond N, Goldin R, Karayiannis P, Rose NJ. Development of hepatic pathology in GBV-B-infected red-bellied tamarins (Saguinus labiatus). J Med Virol 2020; 92:3584-3595. [PMID: 32181899 DOI: 10.1002/jmv.25769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 03/14/2020] [Indexed: 01/08/2023]
Abstract
GB virus B (GBV-B) is a new world monkey-associated flavivirus used to model acute hepatitis C virus (HCV) infection. Critical for evaluation of antiviral or vaccine approaches is an understanding of the effect of HCV on the liver at different stages of infection. In the absence of longitudinal human tissue samples at defined time points, we have characterized changes in tamarins. As early as 2 weeks post-infection histological changes were noticeable, and these were established in all animals by 6 weeks. Despite high levels of liver-associated viral RNA, there was reversal of hepatic damage on clearance of peripheral virus though fibrosis was demonstrated in four tamarins. Notably, viral RNA burden in the liver dropped to near undetectable or background levels in all animals which underwent a second viral challenge, highlighting the efficacy of the immune response in removing foci of replication in the liver. These data add to the knowledge of GBV-B infection in New World primates which can offer attractive systems for the testing of prophylactic and therapeutic treatments and the evaluation of their utility in preventing or reversing liver pathology.
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Quattrocchi A, Mamais I, Tsioutis C, Christaki E, Constantinou C, Koliou M, Pana ZD, Silvestros V, Theophanous F, Haralambous C, Stylianou A, Sotiriou S, Athanasiadou M, Kyprianou T, Demetriou A, Demetriou CA, Kolokotroni O, Gregoriou I, Paphitou N, Panos G, Kostrikis L, Karayiannis P, Petrikkos G, Agathangelou P, Mixides G, Siakallis G, Hadjihannas L, Palazis L, Vavlitou A, Matsentidou-Timiliotou C, Koukios D, Adamidi T, Frangopoulos F, Constantinou E, Nikolopoulos G. Extensive Testing and Public Health Interventions for the Control of COVID-19 in the Republic of Cyprus between March and May 2020. J Clin Med 2020; 9:E3598. [PMID: 33171651 PMCID: PMC7695263 DOI: 10.3390/jcm9113598] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 10/31/2020] [Accepted: 11/05/2020] [Indexed: 12/24/2022] Open
Abstract
Coronavirus disease 2019 (COVID-19) has significantly affected the well-being of individuals worldwide. We herein describe the epidemiology of COVID-19 in the Republic of Cyprus during the first epidemic wave (9 March-3 May 2020). We analyzed surveillance data from laboratory-confirmed cases, including targeted testing and population screening. Statistical analyses included logistic regression. During the surveillance period, 64,136 tests (7322.3 per 100,000) were performed, 873 COVID-19 cases were diagnosed, and 20 deaths were reported (2.3%). Health-care workers (HCWs) represented 21.4% of cases. Overall, 19.1% of cases received hospital care and 3.7% required admission to Intensive Care Units. Male sex (adjusted Odds Ratio (aOR): 3.04; 95% Confidence Interval (CI): 1.97-4.69), increasing age (aOR: 1.56; 95%CI: 1.36-1.79), symptoms at diagnosis (aOR: 6.05; 95%CI: 3.18-11.50), and underlying health conditions (aOR: 2.08; 95%CI: 1.31-3.31) were associated with hospitalization. For recovered cases, the median time from first to last second negative test was 21 days. Overall, 119 primary cases reported 616 close contacts, yielding a pooled secondary attack rate of 12% (95%CI: 9.6-14.8%). Three population-based screening projects, and two projects targeting employees and HCWs, involving 25,496 people, revealed 60 positive individuals (0.2%). Early implementation of interventions with targeted and expanded testing facilitated prompt outbreak control on the island.
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Alexopoulou A, Vasilieva L, Karayiannis P. New Approaches to the Treatment of Chronic Hepatitis B. J Clin Med 2020; 9:jcm9103187. [PMID: 33019573 PMCID: PMC7601587 DOI: 10.3390/jcm9103187] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 02/07/2023] Open
Abstract
The currently recommended treatment for chronic hepatitis B virus (HBV) infection achieves only viral suppression whilst on therapy, but rarely hepatitis B surface antigen (HBsAg) loss. The ultimate therapeutic endpoint is the combination of HBsAg loss, inhibition of new hepatocyte infection, elimination of the covalently closed circular DNA (cccDNA) pool, and restoration of immune function in order to achieve virus control. This review concentrates on new antiviral drugs that target different stages of the HBV life cycle (direct acting antivirals) and others that enhance both innate and adaptive immunity against HBV (immunotherapy). Drugs that block HBV hepatocyte entry, compounds that silence or deplete the cccDNA pool, others that affect core assembly, agents that degrade RNase-H, interfering RNA molecules, and nucleic acid polymers are likely interventions in the viral life cycle. In the immunotherapy category, molecules that activate the innate immune response such as Toll-like-receptors, Retinoic acid Inducible Gene-1 (RIG-1) and stimulator of interferon genes (STING) agonists or checkpoint inhibitors, and modulation of the adaptive immunity by therapeutic vaccines, vector-based vaccines, or adoptive transfer of genetically-engineered T cells aim towards the restoration of T cell function. Future therapeutic trends would likely be a combination of one or more of the aforementioned drugs that target the viral life cycle and at least one immunomodulator.
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Constantinou C, Kolokotroni O, Mosquera M, Heraclides A, Demetriou C, Karayiannis P, Quattrocchi A, Charalambous A. Developing a holistic contingency plan: Challenges and dilemmas for cancer patients during the COVID-19. Cancer Med 2020; 9:6082-6092. [PMID: 32687677 PMCID: PMC7405276 DOI: 10.1002/cam4.3271] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 01/08/2023] Open
Abstract
During the first quarter of 2020 the world is experiencing a pandemic of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2), a novel beta coronavirus that is responsible for the 2019 novel coronavirus disease (COVID-19). The COVID-19 pandemic revealed that healthcare systems around the world were not prepared to deal with either the direct effects of the pandemic or with the indirect effects that are imposed on the health of patients with chronic disorders such as cancer patients. Some challenges and dilemmas currently faced during the pandemic include the management of cancer patients during the treatment and follow-up phases, the assessment of the safety of treatments currently used for the management of SARS-CoV-2 for use in cancer patients, the development of psychoeducation and emotional support for cancer patients and the safe conduct of clinical trials involving participation of cancer patients. Evidence from the literature supports the need for the urgent development of a holistic contingency plan which will include clear guidelines for the protection and comprehensive care of cancer patients. The implementation of such a plan is expected to have many beneficial effects by mainly minimizing the increased morbidity and mortality of cancer patients that could result as an adverse consequence of the COVID-19 or future pandemics.
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Mercuri L, Thomson EC, Hughes J, Karayiannis P. Quasispecies Changes with Distinctive Point Mutations in the Hepatitis C Virus Internal Ribosome Entry Site (IRES) Derived from PBMCs and Plasma. Adv Virol 2018; 2018:4835252. [PMID: 30581467 PMCID: PMC6276526 DOI: 10.1155/2018/4835252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 11/11/2018] [Indexed: 12/12/2022] Open
Abstract
The 5' untranslated region (UTR) of the hepatitis C virus (HCV) genome contains the internal ribosome entry site (IRES), a highly conserved RNA structure essential for cap-independent translation of the viral polyprotein. HCV, apart from the liver, is thought to be associated with lymphocyte subpopulations of peripheral blood mononuclear cells (PBMCs), in lymph nodes and brain tissue. In this study, RT-PCR, cloning, and sequence analysis were employed to investigate the quasispecies nature of the 5'UTR following extraction of viral RNA from PBMCs and plasma of HCV infected individuals. The nucleotide variation between IRES-derived sequences from PBMCs and plasma indicated the existence of polymorphic sites within the IRES. HCV isolates had divergent variants with unique mutations particularly at positions 107, 204, and 243 of the IRES. Most of the PBMC-derived sequences contained an A-A-A variant at these positions. The mutations associated with the IRESes suggested the presence of unique quasispecies populations in PBMCs compared with plasma.
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Alexopoulou A, Karayiannis P. Editorial: HBsAg serum levels in HBeAg-negative chronic HBV infection-is it a matter of genotype? Aliment Pharmacol Ther 2018; 48:102-103. [PMID: 29882982 DOI: 10.1111/apt.14681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Karayiannis P. Hepatitis B virus: virology, molecular biology, life cycle and intrahepatic spread. Hepatol Int 2017; 11:500-508. [PMID: 29098564 DOI: 10.1007/s12072-017-9829-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 10/05/2017] [Indexed: 12/18/2022]
Abstract
Hepatitis B virus is a member of the Hepadnaviridae family and responsible for causing acute and chronic hepatitis in humans. The current estimates of people chronically infected with the virus are put at 250 million worldwide. Immune-mediated liver damage in these individuals may lead to the development of cirrhosis and hepatocellular carcinoma later in life. This review deals with our current understanding of the virology, molecular biology, life cycle and cell-to-cell spread of this very important pathogen, all of which are considered essential for current and future approaches to antiviral treatment.
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Karayiannis P, Thomas HC. Current Status of Hepatitis G
Virus (GBV-C) in Transfusion:
Is It Relevant? Vox Sang 2017. [DOI: 10.1159/000461908] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Mohaghegh Shelmani H, Karayiannis P, Ashtari S, Mahmanzar MA, Khanabadi B, Modami N, Gholipour F, Zare F, Zali MR. Demographic changes of hepatitis B virus infection in Iran for the last two decades. GASTROENTEROLOGY AND HEPATOLOGY FROM BED TO BENCH 2017; 10:S38-S43. [PMID: 29511470 PMCID: PMC5838179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
AIM The objective of this study was to evaluate the impact of the hepatitis B virus (HBV) vaccination program, 24 years after its implementation, by analyzing patients with hepatitis B surface antigen (HBsAg) infection based on gender and age group. BACKGROUND Since the launch of the first universal vaccination program against HBV in Iran in 1993, the epidemiological pattern of HBV prevalence may have changed in our country. METHODS All data for this cross-sectional study were collected from medical records of HBsAg positive patients, who were referred to the Golhak and Armin private laboratories and also to the Gastrointestinal Department of Tehran's Taleghani Hospital and Day Hospital in Iran over a period of 5 years (2011-2016). In total, 8,606 HBsAg positive subjects were assessed according to gender and age group. RESULTS The rates of HBsAg carriage were 0.8%, 7.8%, 49.3%, 27.9% and 14.1% among subjects under 14 years old, 15-24 years, 25-44 years, 45-59 years and those older than 60 years, respectively. According to the age subgroup analyses; the highest (26.2%) and lowest (0.6%) rate of HBsAg positivity was seen in the 31-40 age group and younger than 10 year old children, respectively. CONCLUSION Global vaccination against hepatitis B has significantly reduced carrier rates among children and teenagers under 20 years old in this country. Nevertheless, HBsAg carriers still remain highly prevalent among 25-35-year age group. Therefore, the decline is limited to the younger population born after 1993, and it remains high in the middle-aged individuals.
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Koumbi L, Pollicino T, Raimondo G, Stampoulis D, Khakoo S, Karayiannis P. Hepatitis B virus basal core promoter mutations show lower replication fitness associated with cccDNA acetylation status. Virus Res 2016; 220:150-60. [PMID: 27132039 DOI: 10.1016/j.virusres.2016.04.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/26/2016] [Accepted: 04/26/2016] [Indexed: 02/07/2023]
Abstract
In chronic hepatitis B virus (HBV) infection, variants with mutations in the basal core promoter (BCP) and precore region predominate and associate with more severe disease forms. Studies on their effect on viral replication remain controversial. Increasing evidence shows that epigenetic modifications of cccDNA regulate HBV replication and disease outcome. Here we determined the transcription and viral replication efficiency of well-defined BCP and precore mutations and their effect on cccDNA epigenetic control. HBV monomers bearing BCP mutations A1762T/G1764A and A1762T/G1764A/C1766T, and precore mutations G1896A, G1899A and G1896A/G1899A, were transfected into HepG2 cells using a plasmid-free approach. Viral RNA transcripts were detected by Northern blot hybridization and RT PCR, DNA replicative intermediates by Southern blotting and RT PCR, and viral release was measured by ELISA. Acetylation of cccDNA-bound histones was assessed by Chromatin ImmunoPrecipitation (ChIP) assay and methylation of cccDNA by bisulfite sequencing. BCP mutations resulted in low viral release, mRNA transcription and pgRNA/cccDNA ratios that paralleled the acetylation of cccDNA-bound H4 histone and inversely correlated with the HDAC1 recruitment onto cccDNA. Independently of the mutations, cccDNA was a target for methylation, accompanied by the upregulation of DNMT1 expression and DNMT1 recruitment onto cccDNA. Our results suggest that BCP mutations decrease viral replication capacity possibly by modulating the acetylation and deacetylation of cccDNA-bound histones while precore mutations do not have a significant effect on viral replication. These data provide evidence that epigenetic factors contribute to the regulation of HBV viral replication.
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Koumbi L, Pollicino T, Raimondo G, Kumar N, Karayiannis P, Khakoo SI. Hepatitis B viral replication influences the expression of natural killer cell ligands. Ann Gastroenterol 2016; 29:348-57. [PMID: 27366037 PMCID: PMC4923822 DOI: 10.20524/aog.2016.0036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 03/28/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Hepatitis B virus (HBV) is accounting for over one million deaths annually due to immune-mediated chronic liver damage. Natural killer (NK) cells are abundant in the liver and contribute in HBV persistence. NK cytotoxic effects are controlled by signals from activating and inhibitory receptors. HBV may circumvent host antiviral immunity via the regulation of NK receptors and their ligands. We investigated the effect of viral replication and HBeAg mutations on NK mediators expression in the livers of chronic HBV (CHB) patients and in cell cultures. METHODS HBV monomers bearing hotspot mutations in the basal core promoter and precore region were transfected into HepG2 cells using a plasmid-free assay. Serum viremia and liver HBV RNA were measured in 19 CHB patients. The expression of HBV RNA and of NKG2D ligands, B7H6, DNAX accessory molecule-1, lectin-like transcript 1 (LLT1), LFA-1 and TRAIL was measured in the livers of CHB patients and transfected cells. RESULTS In general, high HBV replication in CHB patients and cell lines upregulated the mRNA of all NK cell ligands and particularly the inhibitory NK cell ligand, LLT1. The exception was the NKG2D ligand, MICA, that was significantly decreased in patients with high serum viremia and intrahepatic HBV RNA levels. CONCLUSIONS HBV replication has differential effects on NK cell ligands suggesting a potential escape mechanisms through up-regulation of LLT1 and down-regulation of MICA. A general trend towards upregulating NK cell ligands can be counteracted by decreasing MICA and hence weakening NK surveillance.
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Koumbi L, Karayiannis P. The Epigenetic Control of Hepatitis B Virus Modulates the Outcome of Infection. Front Microbiol 2016; 6:1491. [PMID: 26779147 PMCID: PMC4701982 DOI: 10.3389/fmicb.2015.01491] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 12/10/2015] [Indexed: 12/14/2022] Open
Abstract
Epigenetic modifications are stable alterations in gene expression that do not involve mutations of the genetic sequence itself. It has become increasingly clear that epigenetic factors contribute to the outcome of chronic hepatitis B virus (HBV) infection by affecting cellular and virion gene expression, viral replication and the development of hepatocellular carcinoma. HBV persists in the nucleus of infected hepatocytes as a stable non-integrated covalently closed circular DNA (cccDNA) which functions as a minichromosome. There are two major forms of HBV epigenetic regulation: posttranslational modification of histone proteins associated with the cccDNA minichromosome and DNA methylation of viral and host genomes. This review explores how HBV can interphase with host epigenetic regulation in order to evade host defences and to promote its own survival and persistence. We focus on the effect of cccDNA bound-histone modifications and the methylation status of HBV DNA in regulating viral replication. Investigation of HBV epigenetic control has important clinical correlates with regards to the development of potential therapeutic regimens that will successfully eradicate HBV infection and deal with HBV reactivation in those undergoing treatment with demethylating agents.
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Foster G, Afdhal NH, Karayiannis P, Thursz M. Welcome to the new, all electronic Journal of Viral Hepatitis. J Viral Hepat 2015; 22:1. [PMID: 25535958 DOI: 10.1111/jvh.12377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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Alexopoulou A, Karayiannis P. Interferon-based combination treatment for chronic hepatitis C in the era of direct acting antivirals. Ann Gastroenterol 2015; 28:55-65. [PMID: 25608803 PMCID: PMC4290005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/26/2014] [Indexed: 11/06/2022] Open
Abstract
The development of protease inhibitors (PIs) such as telaprevir and boceprevir constitutes a milestone in chronic hepatitis C antiviral treatment since it has achieved sustained virological response (SVR) rates of up to 75% in naïve and 29-88% in treatment-experienced patients with genotype 1 infection. Both require combination treatment with pegylated interferon (PEG-IFN) plus ribavirin (RBV) as PI monotherapy results in resistant mutations. New direct acting antiviral agents (DAAs) have recently been approved or their approval is imminent. Simeprevir administered orally as one pill per day in combination with PEG-IFN/RBV will be the next PI to be approved. The SVR rates at about 72-80% for treatment-naïve patients are not a major improvement over telaprevir or boceprevir. However, this treble combination has fewer side effects and drug-drug interactions and most patients undergo shorter treatment duration (24 months) due to earlier treatment responses. Sofosbuvir is the first available once-daily NS5B polymerase inhibitor which has been approved in combination with PEG-IFN/RBV for just 12 weeks with 89% SVR in treatment-naïve patients with genotype 1 infection and 83-100% in treatment-experienced patients with genotypes 2/3. The current review focuses on the recent rapid and continuous developments in the management of chronic HCV infection with DAAs in combination with PEG-IFN/RBV.
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Baltayiannis G, Karayiannis P. Treatment options beyond IFNα and NUCs for chronic HBV infection: expectations for tomorrow. J Viral Hepat 2014; 21:753-61. [PMID: 25271858 DOI: 10.1111/jvh.12307] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 07/01/2014] [Indexed: 12/21/2022]
Abstract
Chronic hepatitis B virus (HBV) infection may progress to cirrhosis, hepatocellular carcinoma (HCC) and end-stage liver failure with time. Interruption of this process can only be achieved through effective antiviral treatment. This approach has so far involved the use of immunomodulators such as pegylated interferon alpha (Peg-IFNα) for a finite period of up to a year and nucleos-(t)ide analogues (NUCs) for treatment over much longer periods of time. The latter act by suppressing HBV replication at the level of DNA synthesis by inhibiting the viral reverse transcriptase/DNA polymerase and causing premature termination of DNA synthesis. The ideal treatment end point is loss of HBsAg in both HBeAg+ve and HBeAg-ve patients following monotherapy. This, however, is only achievable in a minority of patients. Secondary outcomes are durable HBeAg loss and seroconversion to anti-HBe, which occur in about 18-30% of HBeAg+ve patients depending on the antiviral used, and sustained suppression of HBV-DNA accompanied by biochemical normalization and histological improvement in non-HBeAg+ve seroconverting and HBeAg-ve patients. There is therefore a need for additional direct-acting antivirals (DAAs) targeting different stages of the life cycle of the virus, as well as immunotherapeutic approaches. Such developments may pave the way for their use either alone or more likely in combination in the fight against chronic HBV infection. Such drugs or approaches, which are currently undergoing preclinical or clinical testing, are the subject of this review.
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Alexopoulou A, Karayiannis P. HBeAg negative variants and their role in the natural history of chronic hepatitis B virus infection. World J Gastroenterol 2014; 20:7644-7652. [PMID: 24976702 PMCID: PMC4069293 DOI: 10.3748/wjg.v20.i24.7644] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/01/2014] [Accepted: 03/05/2014] [Indexed: 02/06/2023] Open
Abstract
Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection. The appearance of the precore stop codon (with G-for-A substitution at position 1896) and basal core promoter (BCP) (with A-for-T and G-for-A, at positions 1762 and 1764, respectively) variants which reduce or abrogate hepatitis B e antigen (HBeAg) production, heralds the initiation of the seroconversion phase from HBeAg to anti-HBe positivity. The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response (immune clearance phase). Most patients after HBeAg seroconversion become “inactive HBsAg carriers”. However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B (CHB) with high viremia levels (reactivation phase). The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world. This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections. Frequent acute exacerbations accompanied by high viral replication, elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.
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Karamichali E, Foka P, Tsitoura E, Kalliampakou K, Kazazi D, Karayiannis P, Georgopoulou U, Mavromara P. HCV NS5A co-operates with PKR in modulating HCV IRES-dependent translation. INFECTION GENETICS AND EVOLUTION 2014; 26:113-22. [PMID: 24815730 DOI: 10.1016/j.meegid.2014.04.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/15/2014] [Accepted: 04/19/2014] [Indexed: 12/11/2022]
Abstract
Translation initiation of the Hepatitis C virus (HCV) genome is driven by an internal ribosome entry site (IRES), located within the 5' non-coding region. Several studies have suggested that different cellular non canonical proteins or viral proteins can regulate the HCV IRES activity. However, the role of the viral proteins on HCV translation remains controversial. In this report, we confirmed previous studies showing that NS5A down-regulates IRES activity in HepG2 but not in Huh7 cells suggesting that the NS5A effect on HCV IRES is cell-type dependent. Additionally, we provide strong evidence that activated PKR up-regulates the IRES activity while silencing of endogenous PKR had the opposite effect. Furthermore, we present data indicating that the NS5A-mediated inhibitory effect on IRES-dependent translation could be linked with the PKR inactivation. Finally, we show that NS5A from GBV-C but not from GBV-B down-regulates HCV IRES activity in the absence or the presence of PKR over expression. Notably, HCV and GBV-C but not GBV-B NS5A contains a previously identified PKR interacting protein domain.
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Hood SP, Mee ET, Perkins H, Bowen O, Dale JM, Almond NM, Karayiannis P, Bright H, Berry NJ, Rose NJ. Changes in immune cell populations in the periphery and liver of GBV-B-infected and convalescent tamarins (Saguinus labiatus). Virus Res 2013; 179:93-101. [PMID: 24246306 PMCID: PMC3969288 DOI: 10.1016/j.virusres.2013.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 11/03/2013] [Accepted: 11/07/2013] [Indexed: 01/09/2023]
Abstract
GBV-B infection of tamarins is a valuable model for acute HCV infection. We observed distinct expression patterns of PD-1, a marker of T-cell activation, on peripheral and hepatic lymphocytes. Differential PD-1 expression is coincident with reduction in peripheral GBV-B. Liver-associated viral RNA in the absence of peripheral viraemia indicates maintenance of occult infection.
Flaviviruses related to hepatitis C virus (HCV) in suitable animal models may provide further insight into the role that cellular immunity contributes to spontaneous clearance of HCV. We characterised changes in lymphocyte populations in tamarins with an acute GBV-B infection, a hepatitis virus of the flaviviridae. Major immune cell populations were monitored in peripheral and intra-hepatic lymphocytes at high viraemia or following a period when peripheral virus was no longer detected. Limited changes in major lymphocyte populations were apparent during high viraemia; however, the proportions of CD3+ lymphocytes decreased and CD20+ lymphocytes increased once peripheral viraemia became undetectable. Intrahepatic lymphocyte populations increased at both time points post-infection. Distinct expression patterns of PD-1, a marker of T-cell activation, were observed on peripheral and hepatic lymphocytes; notably there was elevated PD-1 expression on hepatic CD4+ T-cells during high viraemia, suggesting an activated phenotype, which decreased following clearance of peripheral viraemia. At times when peripheral vRNA was not detected, suggesting viral clearance, we were able to readily detect GBV-B RNA in the liver, indicative of long-term virus replication. This study is the first description of changes in lymphocyte populations during GBV-B infection of tamarins and provides a foundation for more detailed investigations of the responses that contribute to the control of GBV-B infection.
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Karayiannis P. The Role of the Molecular Biology Laboratory in the Management of Chronic Hepatitis B and C. THALASSEMIA REPORTS 2013. [DOI: 10.4081/thal.2013.s1.e26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Molecular biology techniques are routinely used nowadays to diagnose and evaluate antiviral treatment of patients with chronic hepatitis B (HBV) and hepatitis C virus (HCV) infections. Current tools at our disposal include tests that quantify the amount of circulating virus in the blood, techniques that can analyse genomic sequences to determine viral genotypes or subtypes, or determine amino-acid substitutions that may confer resistance to existing antiviral drugs. What is more, continuously evolving serological tests for the detection of viral antigens or their corresponding antibodies, have made diagnosis of disease as sensitive as possible. The present review will concentrate primarily on molecular diagnostics.
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Mahboobi N, Porter SR, Karayiannis P, Alavian SM. Dental treatment as a risk factor for hepatitis B and C viral infection. A review of the recent literature. JOURNAL OF GASTROINTESTINAL AND LIVER DISEASES : JGLD 2013; 22:79-86. [PMID: 23539395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
BACKGROUND & AIM Patients chronically infected either with hepatitis B (HBV) or hepatitis C virus (HCV) are at increased risk of developing cirrhosis, end stage liver disease and hepatocellular carcinoma. Different risk factors were found to be associated with the transmission of these viruses in various settings. HBV and HCV transmission seems to be also acquired by non-parenteral and non-sexual routes. A large number of patients infected with HCV might have non identifiable routes of viral acquisition. Hence, viral hepatitis transmission risk factors identification is the main way to reduce infection. Dental treatment may be one of such risk factors, and this aspect is addressed in the present literature review, drawing information from existing literature. METHODS An online database search was conducted, limited to publications from January 1999 to February 2012 on specific aspects of HBV and HCV infection, including articles on risk factors, markers of infection, dentistry, epidemiology and transmission. Relevant material was evaluated and reviewed. RESULTS Overall, 53 studies which met the selection criteria were evaluated. Although these studies were from different geographical regions of varied socioeconomic status and study populations and assessed different dental procedures, using different types of statistical analysis, we found that, although weak, there is an all-time risk of HBV and HCV infection during dental treatment. This is more important in developing countries where the rate of hepatitis infected individuals is higher. There is a need for more studies on this subject, properly planned, controlled and analyzed. CONCLUSION Dental treatment can be included among the risk factors of HBV and HCV infection. This risk can easily be eliminated using standard precautionary measures.
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