Hepatitis Associated Aplastic Anemia: A review

Hepatitis-associated aplastic anemia (HAAA) is an uncommon but distinct variant of aplastic anemia in which pancytopenia appears two to three months after an acute attack of hepatitis. HAAA occurs most frequently in young male children and is lethal if leave untreated. The etiology of this syndrome is proposed to be attributed to various hepatitis and non hepatitis viruses. Several hepatitis viruses such as HAV, HBV, HCV, HDV, HEV and HGV have been associated with this set of symptoms. Viruses other than the hepatitis viruses such as parvovirus B19, Cytomegalovirus, Epstein bar virus, Transfusion Transmitted virus (TTV) and non-A-E hepatitis virus (unknown viruses) has also been documented to develop the syndrome. Considerable evidences including the clinical features, severe imbalance of the T cell immune system and effective response to immunosuppressive therapy strongly present HAAA as an immune mediated mechanism. However, no association of HAAA has been found with blood transfusions, drugs and toxins. Besides hepatitis and non hepatitis viruses and immunopathogenesis phenomenon as causative agents of the disorder, telomerase mutation, a genetic factor has also been predisposed for the development of aplastic anemia. Diagnosis includes clinical manifestations, blood profiling, viral serological markers testing, immune functioning and bone marrow hypocellularity examination. Patients presenting the features of HAAA have been mostly treated with bone marrow or hematopoietic cell transplantation from HLA matched donor, and if not available then by immunosuppressive therapy. New therapeutic approaches involve the administration of steroids especially the glucocorticoids to augment the immunosuppressive therapy response. Pancytopenia following an episode of acute hepatitis response better to hematopoietic cell transplantation than immunosuppressive therapy

Hepatitis C Treatment: current and future perspectives

Hepatitis C virus (HCV) is a member of Flaviviridae family and one of the major causes of liver disease. There are about 175 million HCV infected patients worldwide that constitute 3% of world's population. The main route of HCV transmission is parental however 90% intravenous drug users are at highest risk. Standard interferon and ribavirin remained a gold standard of chronic HCV treatment having 38-43% sustained virological response rates. Currently the standard therapy for HCV is pegylated interferon (PEG-INF) with ribavirin. This therapy achieves 50% sustained virological response (SVR) for genotype 1 and 80% for genotype 2 & 3. As pegylated interferon is expensive, standard interferon is still the main therapy for HCV treatment in under developed countries. On the other hand, studies showed that pegylated IFN and RBV therapy has severe side effects like hematological complications. Herbal medicines (laccase, proanthocyandin, Rhodiola kirilowii) are also being in use as a natural and alternative way for treatment of HCV but there is not a single significant report documented yet. Best SVR indicators are genotype 3 and 2, < 0.2 million IU/mL pretreatment viral load, rapid virological response (RVR) rate and age <40 years. New therapeutic approaches are under study like interferon related systems, modified forms of ribavirin, internal ribosome entry site (HCV IRES) inhibitors, NS3 and NS5a inhibitors, novel immunomodulators and specifically targeted anti-viral therapy for hepatitis C compounds. More remedial therapies include caspase inhibitors, anti-fibrotic agents, antibody treatment and vaccines

In vitro and in vivo models to investigate the mechanisms of liver fibrosis and cholestasis

Chronic liver disease (CLD) is a leading cause of mortality around the world and can arise from a range of injuries or insults. Untreated CLD results in liver fibrosis and ultimately can lead to the development of liver cancer. Primary liver cancers include hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). Every year approximately 700,00 people die of liver cancer, making it the third most common cause of cancer death, worldwide (Ferlay et al., 2010). To date, drugs targeting these aggressive cancers have shown minimal benefit in clinical trials and cause a range of side effects. Therefore, improved insights into the underlying mechanisms and pathogenesis of these diseases will facilitate the development of novel drugs. Considering the significance of chronic hepatitis C virus (HCV) infection in the development of liver fibrosis, and to identify potential therapeutic targets, we examined the release of major fibrogenic cytokines from HCV infected cells and monitored their effect on activation of pro-fibrotic hepatic stellate cells. We demonstrated the release of fibrogenic cytokines in several HCV cell culture models, including a subgenomic replicon (SGR) and two full length virus clones, JFH1 and Jc1. We found that TGF-131 and CTGF expression was up regulated more in Jc1 infected cells than in cells containing the SGR or in JFH1 infected cells. Next, we examined the effect of these fibrogenic cytokines on hepatic stellate cells, using the human LX2 cell line and primary rat stellate cells. We demonstrated that the supernatant of Jc1 infected hepatic cells induced up-regulation of fibrotic markers in stellate cells, compared to supernatant from uninfected Huh7 cells. In summary, our results suggest a role for HCV induced cytokines in the development of liver fibrosis in people with chronic hepatitis C. In addition to HCV induced liver fibrosis, a major focus of this thesis is the inflammatory response to cholestasis. Diverse aetiologies result in liver cholestatic disease, which causes toxicity in the liver and ultimately leads to liver fibrosis and frequently liver cancer. A prominent ductular reaction occurs in response to biliary obstruction in cholestatic diseases. This ductular reaction involves the differentiation of bipotentialliver progenitor cells {LPCs) into hepatocytes and cholangiocytes, as well as proliferation of cholangiocytes and liver progenitor cells {LPCs). To date, the mediators of cholangiocyte proliferation in ductular reaction have not been well established. Therefore, we sought to determine the role of Notch and NF-KB signalling in cholangiocyte proliferation. In one animal model, bile duct ligation {BDL) was undertaken in rats to induce ductular reaction. Relative mRNA {qPCR) and protein {western blot) expression of key signalling and downstream molecules were used to determine activation of the Notch and NF-KB pathways. In complementary experiments, expression and localization of Notch and NF-KB signalling molecules was determined by immunofluorescence {IF). Our data suggests activation of both Notch and NF-KB signalling during the proliferation of biliary epithelial cells in cholestatic liver injury. Next, we used a mouse model of cholangiocyte proliferation involving a diethoxycarbonyl dihydrocollidine (DDC) diet, which causes biliary obstruction and cholestasis. We confirmed activation of NF-KB and Notch signalling in this model by real time PCR (qPCR) and found significant up regulation of Notch and canonical NF-KB pathway markers, but no change in the non-canonical NF-KB pathway. Because ductular reaction occurs in response to a range of chronic liver injuries, we decided to study the effect of HCV infection on ductular reaction. We hypothesised that dual insults (HCV and DDC) may exacerbate ductular reaction, so investigated cholangiocyte proliferation and ductular reaction in HCV transgenic (SL139) mice exposed to the DDC diet. In preliminary experiments we observed no change in the expression of Notch or NF-KB signalling in SL139 mice compared to wild type, either by histology or western blot analysis. Finally, we studied the effect of HCV infection on Notch and NF-KB signalling in vitro, as HCV has been proposed to convert infected hepatocytes to biliary cell lineage, resulting in cholangiocarcinoma. We examined activation of the Notch and NF-KB pathways in Jc1 infected Huh? cells, and found significant up regulation of both pathways. Taken together, our data suggest that Notch and NF-KB signalling may play a significant role in cholestatic diseases, including development of cholangiocarcinoma, and could serve as potential therapeutic targets

Inhibitory Potential of Phytochemicals on Interleukin-6-Mediated T-Cell Reduction in COVID-19 Patients: A Computational Approach

Background: A recent COVID-19 pandemic has resulted in a large death toll rate globally and even no cure or vaccine has been successfully employed to combat this disease. Patients have been reported with multi-organ dysfunction along with acute respiratory distress syndrome which implies a critical situation for patients and made them difficult to breathe and survive. Moreover, pathology of COVID-19 is also related to cytokine storm which indicates the elevated levels of interleukin (IL)-1, IL-6, IL-12, and IL-18 along with tumor necrosis factor (TNF)-α. Among them, the proinflammatory cytokine IL-6 has been reported to be induced via binding of severe acute respiratory syndrome coronavirus 2 (SARS)-CoV-2 to the host receptors. Methodology: Interleukin-6 blockade has been proposed to constitute novel therapeutics against COVID-19. Thus, in this study, 15 phytocompounds with known antiviral activity have been subjected to test for their inhibitory effect on IL-6. Based on the affinity prediction, top 3 compounds (isoorientin, lupeol, and andrographolide) with best scores were selected for 50 ns molecular dynamics simulation and MMGB/PBSA binding free energy analysis. Results: Three phytocompounds including isoorientin, lupeol, and andrographolide have shown strong interactions with the targeted protein IL-6 with least binding energies (−7.1 to −7.7 kcal/mol). Drug-likeness and ADMET profiles of prioritized phytocompounds are also very prominsing and can be further tested to be potential IL-6 blockers and thus benficial for COVID-19 treatment. The moelcular dynamics simulation couple with MMGB/PBSA binding free energy estimation validated conformational stability of the ligands and stronger intermolecular binding. The mean RMSD of the complexes is as: IL6-isoorientin complex (3.97 Å ± 0.77), IL6-lupeol (3.97 Å ± 0.76), and IL6-andrographolide complex (3.96 Å ± 0.77). In addition, the stability observation was affirmed by compounds mean RMSD: isoorientin (0.72 Å ± 0.32), lupeol (mean 0.38 Å ± 0.08), and andrographolide (1.09 Å ± 0.49). A similar strong agreement on systems stability was unraveled by MMGB/PBSA that found net binding net ~ −20 kcal/mol for the complexes dominated by van der Waal interaction energy. Conclusion: It has been predicted that proposing potential IL-6 inhibitors with less side effects can help critical COVID-19 patients because it may control the cytokine storm, a major responsible factor of its pathogenesis. In this study, 3 potential phytocompounds have been proposed to have inhibitory effect on IL-6 that can be tested as potential therapeutic options against SARS-CoV-2

Mapping CircRNA–miRNA–mRNA regulatory axis identifies hsa_circ_0080942 and hsa_circ_0080135 as a potential theranostic agents for SARS-CoV-2 infection

Non-coding RNAs (ncRNAs) can control the flux of genetic information; affect RNA stability and play crucial roles in mediating epigenetic modifications. A number of studies have highlighted the potential roles of both virus-encoded and host-encoded ncRNAs in viral infections, transmission and therapeutics. However, the role of an emerging type of non-coding transcript, circular RNA (circRNA) in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has not been fully elucidated so far. Moreover, the potential pathogenic role of circRNA-miRNA-mRNA regulatory axis has not been fully explored as yet. The current study aimed to holistically map the regulatory networks driven by SARS-CoV-2 related circRNAs, miRNAs and mRNAs to uncover plausible interactions and interplay amongst them in order to explore possible therapeutic options in SARS-CoV-2 infection. Patient datasets were analyzed systematically in a unified approach to explore circRNA, miRNA, and mRNA expression profiles. CircRNA-miRNA-mRNA network was constructed based on cytokine storm related circRNAs forming a total of 165 circRNA-miRNA-mRNA pairs. This study implies the potential regulatory role of the obtained circRNA-miRNA-mRNA network and proposes that two differentially expressed circRNAs hsa_circ_0080942 and hsa_circ_0080135 might serve as a potential theranostic agents for SARS-CoV-2 infection. Collectively, the results shed light on the functional role of circRNAs as ceRNAs to sponge miRNA and regulate mRNA expression during SARS-CoV-2 infection

Venn diagram of overlapped differentially expressed circRNAs among circRNAs of circRNA datasets, miRNA datasets and mRNA datasets.

a) Overlapped differentially expressed circRNAs among circRNAs of circRNA datasets, miRNA datasets and mRNA datasets (whole genes). b) Overlapped differentially expressed circRNAs among circRNAs of circRNA datasets, miRNA datasets and mRNA datasets (cytokine storm related mRNAs).</p