0
selected
-
1.
Molecular Dynamics of Fibrinogen Adsorption onto Graphene, but Not onto Poly(ethylene glycol) Surface, Increases Exposure of Recognition Sites That Trigger Immune Response.
Dragneva, N, Rubel, O, Floriano, WB
Journal of chemical information and modeling. 2016;(4):706-20
Abstract
Changes in the conformation of blood proteins due to their binding to nonbiological surfaces is the initial step in the chain of immunological reactions to foreign bodies. Despite the large number of experimental studies that have been performed on fibrinogen adsorption to nonbiological surfaces, a clear picture describing this complex process has eluded researchers to date. Developing a better understanding of the behavior of bioactive fibrinogen motifs upon their interaction with surfaces may facilitate the design of advanced materials with improved biocompatibility. This is especially important within the context of medical implants. Here we present results of explicit-solvent, all-atom MD simulations of the adsorption of the fibrinogen D-domain onto a graphene surface and a poly(ethylene glycol) (PEG) surface. Our results are consistent with experimental observations that interactions with PEG do not induce significant conformational changes on immune-reactive sites present in the D-domain of fibrinogen. In contrast, our results indicate that significant conformational changes induced by adsorption to graphene surfaces may occur under conditions that promote a high density of blood proteins on the surface. The structural rearrangements observed on graphene directly affect the secondary structure content of the D-domain, with consequent exposure of the recognition sites P1 (γ190-202) and P2 (γ377-395) and the subsite P2-C (γ383-395) involved in immune response. Analysis of the structural parameters of the MD conformers was shown to accurately assess the biocompatibility of the modeled surfaces.
-
2.
Latest developments in the treatment of hepatitis B.
Dandri, M, Petersen, J
Minerva gastroenterologica e dietologica. 2016;(1):88-102
Abstract
Chronic hepatitis B virus (HBV) infection continues to be a major health burden worldwide. Currently available antiviral treatment options for chronic hepatitis B include pegylated interferon alpha (PEG-IFN) or nucleos(t)ide analogues (NAs). The major advantages of NAs are good tolerance and potent antiviral activity associated with high rates of on-treatment response to therapy. The advantages of PEG-IFN include a finite course of treatment, the absence of drug resistance, and an opportunity to obtain a durable post-treatment response to therapy. The use of these two antiviral agents with different mechanisms of action in combination is theoretically an attractive approach for treatment. Although several studies have confirmed certain virological advantages of combination therapies, pivotal prospective studies demonstrating long-term clinical benefit to patients are still missing and monotherapy with PEG_IFN or NAs remains the therapy of choice. Furthermore, with the current treatment approaches, only a limited number of patients reach the aim HBsAg loss, which is closest to clinical cure. The limited efficacy of current approved therapeutic regimens demands the development of more efficient therapeutic approaches enabling not only suppression of viral replication, but resolution of HBV infection. The unique replication strategy employed by HBV enables its persistence within the infected hepatocytes. As a consequence, relapse of viral activity is commonly observed after cessation of treatment. Both the persistence of the HBV genome, which forms a stable minichromosome, the covalently closed circular DNA (cccDNA) in the nucleus of infected hepatocytes, as well as the inability of the immune system to resolve chronic HBV infection are believed to be key mechanisms of HBV chronicity. The recent development and availability of innovative in vitro and in vivo systems and sensitive molecular techniques have opened new possibilities to study the complex network of interactions that HBV establishes with the host in the course of infection and to define new targets for antiviral strategies. Several new antiviral or immunomodulatory compounds have reached preclinical or clinical testing with the aim of a clinical cure of chronic HBV with the loss of HBsAg. This review summarizes the most recent therapeutic strategies designed to directly target the virus or to improve immune responses during chronic HBV infection.
-
3.
1(OH) vitamin D3 supplementation improves the sensitivity of the immune-response during Peg-IFN/RBV therapy in chronic hepatitis C patients-case controlled trial.
Kondo, Y, Kato, T, Kimura, O, Iwata, T, Ninomiya, M, Kakazu, E, Miura, M, Akahane, T, Miyazaki, Y, Kobayashi, T, et al
PloS one. 2013;(5):e63672
Abstract
OBJECTIVE 1,25(OH)2 vitamin D3 can affect immune cells. However, the mechanism responsible for the favorable effects of 1(OH) vitamin D3, which becomes 1,25(OH)2 vitamin D3 in the liver, is not clear. The aim of this study is to analyze the immunological response of 1(OH) vitamin D3 supplementation in CH-C patients. DESIGN Forty-two CH-C patients were treated with 1(OH) vitamin D3/Peg-IFNα/RBV. Forty-two case-matched controls were treated with Peg-IFNα/RBV. The expression of Interferon-stimulated genes (ISGs)-mRNA in the liver biopsy samples and JFH-1 replicating Huh-7 cells were quantified by real-time PCR. Ten kinds of cytokines in the plasma were quantified during treatment by using a suspension beads array. A trans-well co-culture system with peripheral blood mononuclear cells (PBMCs) and Huh-7 cells was used to analyze the effect of 1(OH) vitamin D3. The activities of the Th1 response were compared between subjects treated with 1(OH) vitamin D3/Peg-IFN/RBV and those treated with Peg-IFN/RBV therapy alone. RESULTS 1(OH) vitamin D3/Peg-IFN/RBV treatment could induce rapid viral reduction, especially in IL28B T/T polymorphism. Several kinds of cytokines including IP-10 were significantly decreased after 4 weeks of 1(OH) vitamin D3 treatment (p<0.05). Th1 responses in the subjects treated with 1(OH) vitamin D3/Peg-IFN/RBV were significantly higher than those treated with Peg-IFN/RBV at 12 weeks after Peg-IFN/RBV therapy (p<0.05). The expression of ISGs in the patient's liver biopsy samples was significantly lower than in those treated without 1(OH) vitamin D3 (p<0.05). CONCLUSION 1(OH) vitamin D3 could improve the sensitivity of Peg-IFN/RBV therapy on HCV-infected hepatocytes by reducing the IP-10 production from PBMCs and ISGs expression in the liver.
-
4.
Pegylated interferon-α induced hypoferremia is associated with the immediate response to treatment in hepatitis C.
Ryan, JD, Altamura, S, Devitt, E, Mullins, S, Lawless, MW, Muckenthaler, MU, Crowe, J
Hepatology (Baltimore, Md.). 2012;(2):492-500
Abstract
UNLABELLED Pegylated interferon-α (PEG-IFN-α) forms an integral part of the current treatment for hepatitis C virus (HCV) infection. PEG-IFN-α suppresses HCV production by augmenting the innate antiviral immune response. Recent studies have reported the induction of hepcidin, the iron regulatory hormone, by IFN-α in vitro. As hepcidin plays an important role in innate immunity, we hypothesized that this finding may be of clinical relevance to HCV and investigated the changes in iron homeostasis during the first 24 hours of treatment. Blood samples were obtained from HCV patients immediately prior to and 6, 12, and 24 hours following the first dose of PEG-IFN-α/ribavirin (RBV). Samples were analyzed for hepcidin, cytokine, iron levels, and HCV viral load, and hepcidin messenger RNA (mRNA) expression was quantified in peripheral blood mononuclear cells. Hepcidin induction by IFN-α was further analyzed in cell culture. In HCV patients a single dose of PEG-IFN-α/RBV resulted in a significant increase in serum hepcidin, peaking at 12 hours, coinciding with a 50% reduction in serum iron and transferrin saturation over the 24-hour period. Patients with a ≥ 2 log decline in HCV viral load over the first 24 hours had significantly lower SI and TS levels at 12 and 24 hours. Moreover, 24-hour SI levels were an independent predictor of the immediate HCV viral decline, an indicator of ultimate treatment outcome. In cell culture, a direct induction of hepcidin by IFN-α was seen, controlled by the STAT3 transcription factor. CONCLUSION Hepcidin induction occurs following the initiation of PEG-IFN-α treatment for HCV, and is mediated by way of STAT3 signaling. The subsequent hypoferremia was greatest in those with the most significant decline in viral load, identifying systemic iron withdrawal as a marker of immediate interferon-α efficacy in HCV patients.
-
5.
Risk factors for hepatic decompensation in patients with HIV/HCV coinfection and liver cirrhosis during interferon-based therapy.
Mauss, S, Valenti, W, DePamphilis, J, Duff, F, Cupelli, L, Passe, S, Solsky, J, Torriani, FJ, Dieterich, D, Larrey, D
AIDS (London, England). 2004;(13):F21-5
Abstract
OBJECTIVE Hepatic decompensation was reported from two recent trials (APRICOT and RIBAVIC) assessing interferon (IFN)-based treatment of hepatitis C virus (HCV) in HIV/HCV-coinfected patients. This paper identifies risk factors associated with hepatic decompensation in APRICOT. METHODS APRICOT is a randomized, partially-blinded, controlled trial comparing treatment with peg-IFN alpha-2a 180 microg once weekly plus ribavirin/placebo 400 mg twice daily with IFN alpha-2a 3 million units three times weekly plus ribavirin 400 mg twice daily for 48 weeks in a total of 859 patients. Multiple logistic regression analysis was performed comparing the baseline characteristics of those cirrhotic patients who experienced decompensation with those of the other cirrhotic patients enrolled. RESULTS Fourteen patients, all cirrhotic, experienced hepatic decompensation during the study. The incidence in the cirrhotic subgroup of the study was 10.4% (14/134). Six of the 14 patients died as a result of hepatic decompensation. The risk factors associated with hepatic decompensation were increased bilirubin, decreased haemoglobin, increased alkaline phosphatase or decreased platelets, and treatment with didanosine. Markers of viral replication, histological activity, cellular immune status or HCV-therapy, treatment with ribavirin and pegylated versus non-pegylated IFN were not associated with hepatic decompensation. CONCLUSIONS The results from APRICOT indicate that the overall risk of hepatic decompensation in HIV/HCV-coinfected patients without cirrhosis receiving IFN-based treatment is low. In contrast, patients with markers of advanced cirrhosis, despite the absence of a history of hepatic decompensation, should be monitored closely during IFN-based therapy, because they are at risk of hepatic decompensation. Treatment with antiretrovirals such as didanosine may increase the risk further.