Development of Mathematical Models for the Analysis of Hepatitis Delta Virus Viral Dynamics

BACKGROUND: Mathematical models have shown to be extremely helpful in understanding the dynamics of different virus diseases, including hepatitis B. Hepatitis D virus (HDV) is a satellite virus of the hepatitis B virus (HBV). In the liver, production of new HDV virions depends on the presence of HBV. There are two ways in which HDV can occur in an individual: co-infection and super-infection. Co-infection occurs when an individual is simultaneously infected by HBV and HDV, while super-infection occurs in persons with an existing chronic HBV infection. METHODOLOGY/PRINCIPAL FINDINGS: In this work a mathematical model based on differential equations is proposed for the viral dynamics of the hepatitis D virus (HDV) across different scenarios. This model takes into consideration the knowledge of the biology of the virus and its interaction with the host. In this work we will present the results of a simulation study where two scenarios were considered, co-infection and super-infection, together with different antiviral therapies. Although, in general the predicted course of HDV infection is similar to that observed for HBV, we observe a faster increase in the number of HBV infected cells and viral load. In most tested scenarios, the number of HDV infected cells and viral load values remain below corresponding predicted values for HBV. CONCLUSIONS/SIGNIFICANCE: The simulation study shows that, under the most commonly used and generally accepted therapy approaches for HDV infection, such as lamivudine (LMV) or ribavirine, peggylated alpha-interferon (IFN) or a combination of both, LMV monotherapy and combination therapy of LMV and IFN were predicted to more effectively reduce the HBV and HDV viral loads in the case of super-infection scenarios when compared with the co-infection. In contrast, IFN monotherapy was found to reduce the HDV viral load more efficiently in the case of super-infection while the effect on the HBV viral load was more pronounced during co-infection. The results suggest that there is a need for development of high efficacy therapeutic approaches towards the specific inhibition of HDV replication. These approaches may additionally be directed to the reduction of the half-life of infected cells and life-span of newly produced circulating virions

An international genome-wide meta-analysis of primary biliary cholangitis: Novel risk loci and candidate drugs

Backgrounds & Aims Primary biliary cholangitis (PBC) is a chronic liver disease in which autoimmune destruction of the small intrahepatic bile ducts eventually leads to cirrhosis. Many patients have inadequate response to licensed medications, motivating the search for novel therapies. Previous genome-wide association studies (GWAS) and meta-analyses (GWMA) of PBC have identified numerous risk loci for this condition, providing insight into its aetiology. We undertook the largest GWMA of PBC to date, aiming to identify additional risk loci and prioritise candidate genes for in silico drug efficacy screening. Methods We combined new and existing genotype data for 10,516 cases and 20,772 controls from 5 European and 2 East Asian cohorts. Results We identified 56 genome-wide significant loci (20 novel) including 46 in European, 13 in Asian, and 41 in combined cohorts; and a 57th genome-wide significant locus (also novel) in conditional analysis of the European cohorts. Candidate genes at newly identified loci include FCRL3, INAVA, PRDM1, IRF7, CCR6, CD226, and IL12RB1, which each play key roles in immunity. Pathway analysis reiterated the likely importance of pattern recognition receptor and TNF signalling, JAK-STAT signalling, and differentiation of T helper (TH)1 and TH17 cells in the pathogenesis of this disease. Drug efficacy screening identified several medications predicted to be therapeutic in PBC, some of which are well-established in the treatment of other autoimmune disorders. Conclusions This study has identified additional risk loci for PBC, provided a hierarchy of agents that could be trialled in this condition, and emphasised the value of genetic and genomic approaches to drug discovery in complex disorders. Lay summary Primary biliary cholangitis (PBC) is a chronic liver disease that eventually leads to cirrhosis. In this study, we analysed genetic information from 10,516 people with PBC and 20,772 healthy individuals recruited in Canada, China, Italy, Japan, the UK, or the USA. We identified several genetic regions associated with PBC. Each of these regions contains several genes. For each region, we used diverse sources of evidence to help us choose the gene most likely to be involved in causing PBC. We used these ‘candidate genes’ to help us identify medications that are currently used for treatment of other conditions, which might also be useful for treatment of PBC

Virological profiles in hepatitis B virus/hepatitis C virus coinfected patients under interferon plus ribavirin therapy

none10BACKGROUND: Hepatitis C virus (HCV) is believed to exert a suppressive effect on hepatitis B virus (HBV) in most HBV/HCV-coinfected patients; once HCV is cured by interferon-based therapy, these patients may show HBV reactivation. However, recent evidence revealed that the virological status in HBV/HCV-untreated individuals may vary over time and may show fluctuating profiles. METHODS: To evaluate the behaviour of apparently inactive HBV infection in patients under treatment for a concurrent HCV infection, we performed a prospective study that evaluated nine consecutive patients (eight males with a median age of 45.9 years, and one female aged 62 years) longitudinally followed-up with bi-monthly evaluation of HBV/HCV viraemia levels and liver biochemistry during a 1-year treatment with interferon plus ribavirin. RESULTS: In seven cases the HBV infection maintained its inactive status independently of the HCV response to therapy. By contrast, two non-responder cases with persistently high HCV RNA levels showed HBV DNA flairs during the follow-up, indicating a status of active HBV infection with fluctuating virological profiles. CONCLUSIONS: This study suggests that the HBV behaviour may be independent of the HCV activity during anti-HCV therapy in HBV/HCV-coinfected patients, and that the HBV virological profile should be monitored to recognize possible reactivations that might lead to more proper therapeutic choices or adjustmentsnoneSAITTA C; PONTISSO P.; BRUNETTO MR; FARGION S; GAETA GB; NIRO GA; PICCIOTTO A; SMEDILE A; SQUADRITO G; RAIMONDO GSaitta, C; Pontisso, Patrizia; Brunetto, Mr; Fargion, S; Gaeta, Gb; Niro, Ga; Picciotto, A; Smedile, A; Squadrito, G; Raimondo, G