Comparison of fibrosis regression of entecavir alone or combined with pegylated interferon alpha2a in patients with chronic hepatitis B.

BACKGROUND AND AIMS: Antiviral treatment with necleos(t)ide analogues contributes to histological improvement and virologic response in chronic hepatitis B (CHB) patients. However, whether adding pegylated interferon alpha2a (Peg-IFN-α-2a) can help additional clinical benefit, particularly on fibrosis regression was still unknown. METHODS: Chronic hepatitis B patients with pre-treatment biopsy-proven Ishak fibrosis score 2, 3 or 4 were randomly assigned to entecavir (ETV) alone or ETV plus Peg-IFN-α-2a (Peg-IFN-α-2a add-on) group (1:2 ratio). Post-treatment liver biopsy was performed at week 78. Fibrosis regression was defined as decrease in Ishak fibrosis score by ≥ 1 stage or predominantly regressive categorized by P-I-R score. Serum HBV DNA levels were assessed at baseline and every 26 weeks, while HBsAg and HBeAg were evaluated at baseline and every 52 weeks. RESULTS: A total of 218 treatment-naive CHB patients were randomly assigned to ETV alone or Peg-IFN-α-2a add-on group. Totals of 155 patients (ETV alone: Peg-IFN-α-2a add-on, 47:108) were included in statistical analysis. Fibrosis regression rates were 68% (32/47) in the ETV alone and 56% (60/108) in Peg-IFN-α-2a add-on group (p = 0.144). Both groups showed a similar trend of virological suppression during the process of 104-week antiviral therapy (p = 0.132). HBeAg or HBsAg loss or seroconversion rates in the ETV alone group were lower than Peg-IFN-α-2a add-on group though without statistical significance. CONCLUSIONS: Peg-IFN-α-2a add-on therapy did not yield additional fibrosis regression and virologic response than ETV alone therapy.

Delivery of therapeutic AGT shRNA by PEG-Bu for hypertension therapy.

Gene silencing by RNA interference (RNAi) is a promising approach for gene therapy. However, up to today, it is still a major challenge to find safe and efficient non-viral vectors. Previously, we reported PEI-Bu, a small molecular weight PEI derivative, as an efficient non-viral carrier. However, like many PEI-based polymers, PEI-Bu was too toxic. In order to reduce cytotoxicity while maintain or even enhance transfecion efficiency, we modified PEI-Bu with poly(ethylene glycol) (PEG) to obtain PEG-Bu, and used it to delivery a theraputic short hairpin RNA (shRNA) targeting angiotensinogen (AGT) to normal rat liver cells (BRL-3A), which was a key target for the treatment of hypertension. The structure of PEG-Bu was confirmed by proton nuclear magnetic resonance ((1)H-NMR). Gel permeation chromatography (GPC) showed that the weight average molecular weight (Mw) of PEG-Bu was 5880 Da, with a polydispersity of 1.58. PEG-Bu could condense gene cargo into spherical and uniform nanoparticles with particle size (65-88 nm) and zeta potential (7.3-9.6 mV). Interestingly and importantly, PEG-Bu displayed lower cytotoxicity and enhanced tranfection efficiency than PEI-Bu after PEGylation in both normal cells BRL-3A and tumor cells HeLa. Moreover, PEG-Bu could efficiently delivery AGT shRNA to knockdown the AGT expression. To sum up, PEG-Bu would be a promising non-viral vector for delivering AGT shRNA to BRL-3A cells for hypertension therapy.

Hepatocyte-targeting gene transfer mediated by galactosylated poly(ethylene glycol)-graft-polyethylenimine derivative.

Biscarbamate cross-linked polyethylenimine derivative (PEI-Et) has been reported as a novel nonviral vector for efficient and safe gene transfer in our previous work. However, it had no cell-specificity. To achieve specific delivery of genes to hepatocytes, galactosylated poly(ethylene glycol)-graft-polyethylenimine derivative (GPE) was prepared through modification of PEI-Et with poly(ethylene glycol) and lactobionic acid, bearing a galactose group as a hepatocyte-targeting moiety. The composition of GPE was characterized by proton nuclear magnetic resonance. The weight-average molecular weight of GPE measured with a gel permeation chromatography instrument was 9489 Da, with a polydispersity of 1.44. GPE could effectively condense plasmid DNA (pDNA) into nanoparticles. Gel retardation assay showed that GPE/pDNA complexes were completely formed at weigh ratios (w/w) over 3. The particle size of GPE/pDNA complexes was 79-100 nm and zeta potential was 6-15 mV, values which were appropriate for cellular uptake. The morphology of GPE/pDNA complexes under atomic force microscopy appeared spherical and uniform in size, with diameters of 53-65 nm. GPE displayed much higher transfection efficiency than commercially available PEI 25 kDa in BRL-3A cell lines. Importantly, GPE showed good hepatocyte specificity. Also, the polymer exhibited significantly lower cytotoxicity compared to PEI 25 kDa at the same concentration or weight ratio in BRL-3A cell lines. To sum up, our results indicated that GPE might carry great potential in safe and efficient hepatocyte-targeting gene delivery.

Molecular cloning and characterization of a gamma-glutamylcysteine synthetase gene from Chorispora bungeana.

Chorispora bungeana Fisch. and C.A. Mey (C. bungeana) is a rare alpine subnival plant species that is highly tolerant of freezing temperatures. Glutathione (GSH) is a major player in various metabolic processes involved in plant growth and development and stress responses. A recent study has found that the inhibition of GSH synthesis decreases the chilling tolerance of C. bungeana callus (J. Wu et al.: Cryobiology 57:9-17, 2008). We have isolated and characterized a full-length cDNA encoding gamma-glutamylcysteine synthetase (Cb gamma ECS), the key enzyme of GSH synthesis, from the leaves of C. bungeana, with the aim of furthering our understanding of the role of GSH at the molecular level. Cb gamma ECS was found to encode a 524-amino acid protein with moderate to high nucleotide sequence similar to previously reported plant gamma-ECS genes. Cb gamma ECS transcripts were detected in the calluses, roots and leaves of C. bungeana, but there was no tissue-specific expression. The transcripts of Cb gamma ECS accumulated both rapidly and at high levels when C. bungeana was treated with chilling (4 degrees C), freezing (-4 degrees C), several other environmental stresses (such as heat, salinity, osmotic and heavy metals), abscisic acid and hydrogen peroxide. These results suggest that Cb gamma ECS may participate in the cellular responses against multiple environmental stimuli in C. bungeana.