Hepatitis C virus infection of human cytotrophoblasts cultured in vitro.

Hepatitis C virus (HCV) infection in the uterus is a significant path of vertical HCV transmission. Some studies consider vertical HCV transmission in the uterus as the result of maternal blood leakage into infant blood, whereas others theorize that HCV is transmitted by the mother to the infant through cells constituting the placenta barrier. Although trophoblasts play an important role in the placenta barrier, no definitive evidence has been presented to prove that cytotrophoblasts can be infected with HCV. The current study investigated whether or not these can be infected with HCV by conducting an experiment, in which cultured human cytotrophoblasts were infected with HCV in vitro. The results were analyzed using reverse transcription polymerase chain reaction (RT-PCR), ultrastructural characteristic changes under an electron microscope, and immunoelectron microscopy. HCV RNA in the supernatant of the cultured medium of the infected group was intermittently detected during the 16-day incubation period using RT-PCR. Under an electron microscope, the ultrastructures of infected human cytotrophoblasts were markedly different from normal cells, demonstrating lysosomal hyperplasia, rough endoplasmic reticulum, decreased lipid droplets, presence of vacuoles, and the appearance of HCV-like particles. Using immunoelectron microscopy, HCV-like particles conjoined with golden granules were also observed. Based on the data, the current study concludes that HCV infects a human cytotrophoblast cultured in vitro; moreover, its ultrastructure changes dramatically upon infection.

Drug-Drug Interactions of Newly Approved Direct-Acting Antiviral Agents in Patients with Hepatitis C.

Hepatitis C is a major health problem worldwide, frequently resulting in cirrhosis and increasing the risk of hepatocellular carcinoma significantly. In recent years, the advent of direct-acting antivirals (DAAs) has dramatically improved the therapeutic outcomes in hepatitis C patients. In the last two years, several new DAA combinations have been approved for the treatment of the hepatitis C virus (HCV) infection, including elbasvir/grazoprevir, sofosbuvir/velpatasvir, sofosbuvir/velpatasvir/voxilaprevir, and glecaprevir/pibrentasvir. The newly approved DAA regimens may be prescribed with other drugs simultaneously, increasing the potential of pharmacokinetic interactions. Therefore, the knowledge and management of drug-drug interactions (DDIs) with DAAs should be considered a key issue in HCV therapy. This review summarizes researches of DDIs focusing on newly approved DAAs (elbasvir, grazoprevir, velpatasvir, voxilaprevir, glecaprevir, pibrentasvir) for patients undergoing HCV treatment to provide clinical consideration for comedication. With respect to DDIs, newly approved DAA regimens, including elbasvir/grazoprevir, sofosbuvir/velpatasvir, sofosbuvir/velpatasvir/voxilaprevir, and glecaprevir/pibrentasvir, are safely applicable.

Inhibitory effect of antisense oligonucleotide targeting TIMP-2 on immune-induced liver fibrosis.

INTRODUCTION: We previously reported that both experimental and human studies have shown the importance of TIMP-1 and TIMP-2 in the development of liver fibrosis, a disease mostly caused by HBV and HCV infection in China. Inhibiting the expression of TIMP-1 by an antisense oligonucleotide (ASON) can prevent liver fibrosis through decreasing the deposition of collagen I and III. Whether blocking the expression of TIMP-2 has the same effect on liver fibrosis is not clear. MATERIALS AND METHODS: To interfere with this potentially effective target, we designed and synthesized two different ASON targeting TIMP-2, then mixed and transfected them by hydrodynamic injection into the rat livers with immune-induced liver fibrosis. We isolated HSCs from the HSA-induced rat model with liver fibrosis, and transfected them with ASON or sense oligonucleotide in vitro. RESULTS: We observed that TIMP-2 ASON markedly reduced the expression of TIMP-2 by real-time PCR, Western blot, and enzyme linked immunosorbent assay. However, TIMP-2 ASON had little effect on alpha-SMA expression in vitro by Western blot. Inhibition of the expression of TIMP-2 by TIMP-2 ASON clearly decreased deposition of collagen I and IV, ameliorated liver pathology, and improved the liver function among the rats with immune-induced liver fibrosis. CONCLUSION: The results suggested that TIMP-2 ASON could prevent the progression of liver fibrosis in this rat model. It is possible that this could form the basis for exploration of new liver anti-fibrosis drugs at a genetic level.

Expression of dendritic cell-specific intercellular adhesion molecule 3 grabbing nonintegrin on dendritic cells generated from human peripheral blood monocytes.

AIM: To generate dendritic cells (DCs) from human peripheral blood and to detect the expression of dendritic cell-specific intercellular adhesion molecule 3 grabbing nonintegrin (DC-SIGN; CD209) for the further study of DC-SIGN in hepatitis C virus (HCV) transmission. METHODS: Peripheral blood monocytes were isolated from blood of healthy individuals by Ficoll-Hypaque sedimentation and cultured in complete medium containing rhGM-CSF and rhIL-4. Cells were cultured for seven days, with cytokine addition every two days to obtain immature DCs. Characteristics of the cultured cells were observed under light and scanning microscope, and the expression of DC-SIGN was detected by immunofluorescence staining. RESULTS: After seven-day culture, a large number of cells with typical characteristics of DCs appeared. Their characteristics were observed under light and scanning electron microscope. These cells had a variety of cell shapes such as those of bipolar elongate cells, elaborate stellate cells and DCs. DC-SIGN was detected by immunofluorescence staining and its expression level on cultivated dendritic cells was high. CONCLUSION: DCs with a high expression of DC-SIGN can be generated from human peripheral blood monocytes in complete medium containing rhGM-CSF and rhIL-4.

Correlation between TIMP-1 expression and liver fibrosis in two rat liver fibrosis models.

AIM: To evaluate serum TIMP-1 level and the correlation between TIMP-1 expression and liver fibrosis in immune-induced and CCL4-induced liver fibrosis models in rats. METHODS: Immune-induced and CCL4-induced liver fibrosis models were established by dexamethasone (0.01 mg) and CCL4 respectively. Serum TIMP-1 level was detected with ELISA, while histopathological grade of liver biopsy was evaluated. Spearman rank-correlation test was used to analyse the difference of the correlation between the TIMP-1 expression and hepatic fibrosis in the two fibrosis models. Furthermore, in situ hybridization was used to determine the expression difference of TIMP-1 mRNA in the two models. RESULTS: Positive correlation existed between serum TIMP-1 level of immune induced group and the histopathological stages of fibrosis liver of corresponding rats (Spearman rank-correlation test, r(s) = 0.812, P < 0.05), and the positive in situ hybridization signal of TIMP-1 mRNA was strong. In CCL4-induced liver fibrosis model, the correlation between the serum TIMP-1 level and the severity of hepatic fibrosis was not statistically significant(Spearman rank-correlation test, r(s) = 0.229, P > 0.05). And compared with immune-induced model, the positive in situ hybridization signal of TIMP-1 mRNA was weaker, while the expression variation was higher in hepatic fibrosis of the same severity. CONCLUSION: The correlations between TIMP-1 expression and liver fibrosis in two rat liver fibrosis models are different. In immune-induced model, serum TIMP-1 level could reflect the severity of liver fibrosis, while in CCL4-induced model, the correlation between the serum TIMP-1 level and the severity of hepatic fibrosis was not statistically significant.

Induction of hepatitis C virus-specific cytotoxic T and B cell responses by dendritic cells expressing a modified antigen targeting receptor.

AIM: To find a novel antigen (Ag) presentation strategy to improve the immune responses induced by dendritic cell (DC) vaccine expressing hepatitis C virus (HCV) core antigen (pcDNA3HCV C-Fc) in Balb/c mice (H-2d). METHODS: pcDNA3HCV C-Fc plasmid and eukaryotic expression vector pcDNA3 were injected into mice sc. Immune responses to pcDNA3HCV C-Fc were studied. Meanwhile the effect of pcDNA3HCV C-Fc on anti-translated subcutaneous tumor of SP2/0 cells stably expressing HCV C Ag (SP2/0-HCV C-FC) was also studied. Anti-HCV C in serum was detected by enzyme-linked immunoadsordent assay (ELISA) and HCV specific cytotoxic T lymphocyte (CTL) activity was measured by LDH release assay. After 3 wk of DNA immunization, the cells of SP2/0-HCV C-FC were inoculated into mice subcutaneously and tumor growth was measured every 5 d. The survival rate and living time of mice were also calculated. RESULTS: After 4 wk of DC immunization, the A(450 nm) values of sera in mice immunized with pcDNA3HCV C-Fc-DC and pcDNA3-DC were 0.56+/-0.17 and 0.12+/-0.03 respectively. The antibody titres in mice codeliveried with pcDNA3HCV C-Fc with DC were significantly higher than those of mice injected with pcDNA3-DC. The HCV specific CTL activities in mice coinjected with DC and pcDNA3HCV C-Fc or empty expression vectors were (73.2+/-3.1)% and (24.4+/-8.8)%, which were significantly higher than those of mice injected with water. The DC vaccine could evidently inhibit tumor growth, prolong the survival time of mice and improve the survival rate of mice and these effects could be improved by HCV C-Fc (pcDNA3HCV C-Fc) gene codelivered. CONCLUSION: DC vaccine has a strong antigenicity in humoral and cellular immunities, which can be promoted by transduced pcDNA3HCV C-Fc expressing HCV C or Fc. Thus, pcDNA3HCV C-Fc-transduced DCs may be a promising candidate for a CTL-based vaccine against HCV.

Advances in clinical diagnosis and treatment of severe acute respiratory syndrome.

It has been proved that severe acute respiratory syndrome (SARS) is caused by SARS-associated coronavirus, a novel coronavirus. SARS originated in Guangdong Province, the People's Republic of China at the end of 2002. At present, it has spread to more than 33 countries or regions all over the world and affected 8 360 people and killed 764 by May 31,2003. Identification of the SARS causative agent and development of a diagnostic test are important. Detecting disease in its early stage, understanding its pathways of transmission and implementing specific prevention measures for the disease are dependent upon swift progress. Due to the efforts of the WHO-led network of laboratories testing for SARS, tests for the novel coronavirus have been developed with unprecedented speed. The genome sequence reveals that this coronavirus is only moderately related to other known coronaviruses. WHO established the definitions of suspected and confirmed and probable cases. But the laboratory tests and definitions are limited. Until now, the primary measures included isolation, ribavirin and corticosteroid therapy, mechanical ventilation, etc. Other therapies such as convalescent plasma are being explored. It is necessary to find more effective therapy. There still are many problems to be solved in the course of conquering SARS.

Current status of severe acute respiratory syndrome in China.

Severe acute respiratory syndrome (SARS), also called infectious atypical pneumonia, is an emerging infectious disease caused by a novel variant of coronavirus (SARS-associated coronavirus, SARS-CoV). It is mainly characterized by pulmonary infection with a high infectivity and fatality. SARS is swept across almost all the continents of the globe, and has currently involved 33 countries and regions, including the mainland China, Hong Kong, Taiwan, North America and Europe. On June 30, 2003, an accumulative total reached 8450 cases with 810 deaths. SARS epidemic was very rampant in March, April and May 2003 in the mainland of China and Hong Kong. Chinese scientists and healthcare workers cooperated closely with other scientists from all over the world to fight the disease. On April 16, 2003, World Health Organization (WHO) formally declared that SARS-CoV was an etiological agent of SARS. Currently, there is no specific and effective therapy and prevention method for SARS. The main treatments include corticosteroid therapy, anti-viral agents, anti-infection, mechanical ventilation and isolation. This disease can be prevented and controlled, and it is also curable. Under the endeavor of the Chinese Government, medical staffs and other related professionals, SARS has been under control in China, and Chinese scientists have also made a great contribution to SARS research. Other studies in developing new detection assays and therapies, and discovering new drugs and vaccines are in progress. In this paper, we briefly review the current status of SARS in China.

RNA interference: antiviral weapon and beyond.

RNA interference (RNAi) is a remarkable type of gene regulation based on sequence-specific targeting and degradation of RNA. The term encompasses related pathways found in a broad range of eukaryotic organisms, including fungi, plants, and animals. RNA interference is part of a sophisticated network of interconnected pathways for cellular defense, RNA surveillance, and development and it may become a powerful tool to manipulate gene expression experimentally. RNAi technology is currently being evaluated not only as an extremely powerful instrument for functional genomic analyses, but also as a potentially useful method to develop specific dsRNA based gene-silencing therapeutics. Several laboratories have been interested in using RNAi to control viral infection and many reports in Nature and in Cell show that short interfering (si) RNAs can inhibit infection by HIV-1, polio and hepatitis C viruses in a sequence-specific manner. RNA-based strategies for gene inhibition in mammalian cells have recently been described, which offer the promise of antiviral therapy.

A small yeast RNA inhibits HCV IRES mediated translation and inhibits replication of poliovirus in vivo.

AIM: To investigate the anti-virus infection activity of internal ribosome entry site (IRES) specific inhibitor RNA (IRNA). METHODS: IRNA eukaryotic vector pcRz-IRNA or mIRNA eukaryotic vector pcRz-mIRNA was transfected into human hepatocarcinoma cells (HHCC), then selected with neomycin G418 for 4 to 8 weeks, and then infected with polio virus vaccines line. The cytopethogenesis effect was investigated and the cell extract was collected. At last the polio virus titer of different cells was determined by plaque assay. RESULTS: Constructive expression of IRNA was not detrimental to cell growth. HCV IRES-mediated cap-independent translation was markedly inhibited in cells constructively expressing IRNA compared to control hepatoma cells. However, cap-dependent translation was not significantly affected in these cell line. Additionally, HHCC cells constitutively expressing IRNA became refractory to infection of polio virus. CONCLUSION: IRES specific IRNA can inhibit HCV IRES mediated translation and poliovirus replication.

DC-SIGN: binding receptor for HCV?

DC-SIGN, a dendritic Cell-specific adhesion receptor and a type II transmembrane mannose-binding C-type lectin, is very important in the function of DC, both in mediating naive T cell interactions through ICAM-3 and as a rolling receptor that mediates the DC-specific ICAM-2-dependent migration processes. It can be used by viral and bacterial pathogens including Human Immunodeficiency Virus (HIV), HCV, Ebola Virus, CMV and Mycobacterium tuberculosis to facilitate infection. Both DC-SIGN and DC-SIGNR can act either in cis, by concentrating virus on target cells, or in trans, by transmission of bound virus to a target cell expressing appropriate entry receptors. Recent work showed that DC-SIGN are high-affinity binding receptors for HCV. Besides playing a role in entry into DC, HCV E2 interaction with DC-SIGN might also be detrimental for the interaction of DC with T cells during antigen presentation. The clinical strategies that target DC-SIGN may be successful in restricting HCV dissemination and pathogenesis as well as directing the migration of DCs to manipulate appropriate immune responses in autoimmunity and tumorigenic situations.

Expression of TIMP-1 and TIMP-2 in rats with hepatic fibrosis.

AIM: To investigate the location and expression of TIMP-1 and TIMP-2 in the liver of normal and experimental hepatic fibrosis in rats. METHODS: The rat models of experimental immunity hepatic fibrosis (n=20) were prepared by the means of immunologic attacking with human serum albumin (HSA), and normal rats (n=10) served as control group. Both immunohistochemistry and in situ hybridization methods were respectively used to detect the TIMP-1 and TIMP-2 mRNA and related antigens in liver. The liver tissue was detected to find out the gene expression of TIMP-1 and TIMP-2 with RT-PCR. RESULTS: The TIMP-1 and TIMP-2 related antigens in livers of experimental group were expressed in myofibroblasts and fibroblasts (TIMP-1: 482+/-65 vs 60+/-20; TIMP-2: 336+/-48 vs 50+/-19, P<0.001). This was the most obvious in portal area and fibrous septum. The positive signals were located in cytoplasm, not in nucleus. Such distribution and location were confirmed by situ hybridization (TIMP-1/beta-actin: 1.86+/-0.47 vs 0.36+/-0.08; TIMP-2/beta-actin: 1.06+/-0.22 vs 0.36+/-0.08, P<0.001). The expression of TIMP-1 and TIMP-2 was seen in the liver of normal rats, but the expression level was very low. However, the expression of TIMP-1 and TIMP-2 in the liver of experimental group was obviously high. CONCLUSION: In the process of hepatic fibrosis, fibroblasts and myofibroblasts are the major cells that express TIMPs. The more serious the hepatic fibrosis is in the injured liver, the higher the level of TIMP-1 and TIMP-2 gene expression.

Methodologic research on TIMP-1, TIMP-2 detection as a new diagnostic index for hepatic fibrosis and its significance.

AIM: To set up a new method to detect tissue inhibitors of metalloproteinase-1 and -2(TIMP-1 and TIMP-2) in sera of patients with hepatic cirrhosis, and to investigate the expression and location of TIMP-1 and TIMP-2 in liver tissue of patients with hepatic cirrhosis, and the correlation between TIMPs in liver and those in sera so as to discuss whether TIMPs can be used as a diagnosis index of hepatic fibrosis. METHODS: The monoclonal antibodies (McAbs) of TIMP-1 and TIMP-2 were used to sensitize erythrocytes, and solid-phase absorption to sensitized erythrocytes (SPASE) was used to detect TIMP-1 and TIMP-2 in the sera of patients with hepatic cirrhosis. Meanwhile, with the method of in situ hybridization and immunohistochemistry, we studied the mRNA expression and antigen location of TIMP-1 and TIMP-2 in the livers of 40 hepatic cirrhosis patients with pathologic diagnosis. RESULTS: With SPASE, they were 16.4% higher in the acute hepatitis group, 33.3% higher in the chronic hepatitis group, and the positive rates were 73.6% and 61.2% respectively in sera of hepatic cirrhosis patients, which were remarkably higher than those in chronic hepatitis and acute hepatitis group (P<0.001). In 40 samples of hepatic cirrhosis tissues, all of them showed positive expression of TIMP-1 and TIMP-2 mRNA detected with immunohistochemistry or in situ hybridization (positive rate was 100%). Expression of TIMPs in different degrees could be found in liver tissue with cirrhosis. TIMPs were located in cytoplasm of liver cells of patients with hepatic cirrhosis. There was a significant correlation between serum TIMPs level and liver TIMPs level. CONCLUSION: SPASE is a useful method to detect the TIMP-1 and TIMP-2 in sera of patients with hepatic cirrhosis, and TIMP-1 and TIMP-2 can be considered as a useful diagnostic index of hepatic fibrosis, especially TIMP-1.

DC-SIGN: binding receptors for hepatitis C virus.

OBJECTIVE: To review the recent developments in and research into binding receptors of hepatitis C virus (HCV) and especially the role of dendritic cell-specific adhesion receptor (DC-SIGN) in HCV. DATA SOURCES: Both Chinese- and English-language literature was searched using MEDLINE (2000 - 2003) and the databank of Chinese-language literature (2000 - 2003). STUDY SELECTION: Relevant articles on DC-SIGN and HCV binding receptors in recent domestic and foreign literature were selected. DATA EXTRACTION: Data were mainly extracted from 40 articles which are listed in the references section of this review. RESULTS: DC-SIGN, a dendritic cell-specific adhesion receptor and a type II transmembrane mannose-binding C-type lectin, is very important in the function of dendritic cells (DC), both in mediating naïve T cell interactions through ICAM-3 and as a rolling receptor that mediates the DC-specific ICAM-2-dependent migration processes. It can be used by HCV and other viral and bacterial pathogens including human immunodeficiency virus (HIV), Ebola virus, CMV and Mycobacterium tuberculosis to facilitate infection. Both DC-SIGN and DC-SIGNR can act either in cis, by concentrating virus on target cells, or in trans, by transmission of bound virus to a target cell expressing appropriate entry receptors. Recent report showed that DC-SIGN not only plays a role in entry into DC, HCV E2 interaction with DC-SIGN might also be detrimental to the interaction of DC with T cells during antigen presentation. CONCLUSIONS: DC-SIGNs are high-affinity binding receptors for HCV. The clinical strategies that target DC-SIGN may be successful in restricting HCV dissemination and pathogenesis as well as directing the migration of DCs to manipulate appropriate immune responses in autoimmunity and tumorigenic situations.

[The relationship between cellular infection by Hantaan virus and expression of beta3 integrin].

OBJECTIVE: To investigate the relationship between cellular entry of Hantaan virus (HTNV) and expression of beta3 integrin in beta3-integrin-deficient and HTNV-insusceptible China hamster ovary (CHO) cells. METHODS: Eukaryotic expression vector encoding human integrin beta3 and eukaryotic expression vector harboring human integrin alphav or alphaIIb subunit cDNA were transfected into HTNV non-permissive CHO cells individually or collectively. Screening for stable transfectant clones was performed using G418 selective (culture medium. The exogenous gene expression was analyzed qualitatively and quantitatively by immunofluorescence assay (IFA) and flow cytometry (FCM). Various modified CHO cells and untransfected CHO cells were infected using HTNV A9. At various time points after infection, HTNV antigens in infected cells were detected qualitatively and quantitatively by IFA, FCM. RESULTS: Highly-effective surface expression of beta3 integrin was measured in CHO/alphavbeta3 and CHO/alphaIIbbeta3, while weaker surface expression was detected in CHO/beta3 (P < 0.05). Expression of alphav or alphaIIb integrin in the individually transfected group was significantly lower than in the cotransfected group (P < 0.01) and the sites of localization changed. In contrast, effective surface expression was not seen when pcDNA3 was transfected alone. The infection rate of CHO/alphavbeta3 (60.1%) and CHO/alphaIIbbeta3 (55. 9%) cells were significantly higher than that of CHO/beta3 (38.7%) cells, while the infection rate of CHO/beta3 was significantly higher than that of CHO/alphav, CHO/pcDNA3 and CHO cells respectively. There was a close relationship between the positive percentage of HTNV A9-infected cells and expression of beta3 integrin. CONCLUSION: These results indicated that cellular entry of HTNV was related to the expression of beta3 integrin.

Botulism, where are we now?

INTRODUCTION: Botulism is a neuroparalytic illness caused by botulinum toxin, a product of the Clostridium botulinum bacteria and characteristically presents as an acute, symmetrical, descending flaccid paralysis. Albeit it is the most poisonous substance known, which even poses a major threat as biological weapons, purified and highly diluted botulinum toxin can be used to treat a wide variety of conditions associated with muscular hyperactivity, glandular hypersecretions and pain. There are six clinical presentations associated with current occurring botulism, each results from absorption of botulinum toxin into the bloodstream. AIM: The aim of this review is to summarize the current knowledge on the microbiology, epidemiology, vaccine research and clinical management of human botulism. CONCLUSIONS: Early diagnosis and management rely on history and physical examination. Delay in treatment may allow progression of paralysis, protracted hospitalization and deaths of long-term mechanical ventilation and intensive care unit care. The clinicians must take this disease into consideration of a possible outbreak. Awaiting laboratory confirmation is an egregious error, while awareness of the clinical sign and symptoms of botulism is critical for early diagnosis. Rapid management and followed public health surveillance may greatly alleviate disease severity and decrease mortality rates.

Effects of intestinal intervention on bacterial translocation in a rat model of acute liver failure in vivo.

BACKGROUND/AIMS: The study aimed to confirm bacterial translocation (BT) in rats with acute liver failure (ALF), to explore the correlation between the concentration of lipopolysaccharides and Toll-like receptor 4 (TLR4) expression, and further, to evaluate the curative effects of lactulose and montmorillonite (smecta) in this setting. METHODS: D-Galactosamine was injected into the abdominal cavity of rats to induce ALF. Escherichia coli JM109 labeled with enhanced green fluorescent protein was administered to track BT. Simultaneously, the rats were given lactulose or smecta. Blood samples were collected for measuring liver function, cytokines, endotoxins, and TLR4 expression. Representative tissue specimens from the liver, spleen, and mesenteric lymph nodes were aseptically harvested for bacterial identification by agarose gel electrophoresis, laser scanning confocal microscopy, and flow cytometry. RESULTS: BT occurred in ALF, accompanied by impaired liver function with increased cytokines, endotoxins, and TLR4 expression. After the treatment with lactulose or smecta, all these parameters decreased, including the relative quantity of translocated bacteria while albumin increased. Furthermore, compared with the lactulose treatment group, the parameters in the smecta treatment group improved. Moreover, in the group in which smecta was given for prophylaxis, there was greater improvement than with treatment. CONCLUSION: Intestinal intervention with lactulose or smecta can ameliorate BT; moreover, smecta has a better effect than lactulose, and its preventive effect was also better than its therapeutic effect.