Comparison of the efficacy of thymosin alpha-1 and interferon alpha in the treatment of chronic hepatitis B: a meta-analysis

Chronic hepatitis B virus (HBV) infection is a serious problem because of its worldwide distribution and possible adverse sequelae, such as cirrhosis and hepatocellular carcinoma. Thymosin alpha-1 (Talpha1) is an immune modifier that has been shown to be effective for chronic hepatitis B (CHB) in some trials. But the trials comparing Talpha1 vs. interferon alpha (IFNalpha) treatment in CHB have been small and the results have been inconsistent. So we conducted a meta-analysis to compare the efficacy of Talpha1 and IFNalpha in the treatment of CHB. Generally, four randomized controlled trials including 199 CHB patients who received Talpha1 or IFNalpha treatment were identified through MEDLINE and EMBASE online search. Virological (for hepatitis B e antigen (HBeAg) positive patients, loss of HBV DNA and HBeAg; for HBeAg negative patients, loss of HBV DNA), biochemical (normalization of transaminases) and complete responses (fulfill criteria of biochemical and virological response simultaneously) were analyzed using the intention-to-treat method. The odds ratio (OR) was used to measure the magnitude of the efficacy. The ORs (95% confidence interval) of the virological response, biochemical response and complete response of Talpha1 over IFNalpha at the end of 6 months treatment were 0.62 (0.35, 1.10), 0.60 (0.34, 1.05) and 0.54 (0.30, 0.97), respectively. The ORs (95% confidence interval) of the virological response, biochemical response and complete response of Talpha1 over IFNalpha at the end of follow-up (6 months post-treatment) were 3.71 (2.05, 6.71), 3.12 (1.74, 5.62) and 2.69 (1.47, 4.91), respectively. These data showed that compared with IFNalpha, the benefit of Talpha1 was not immediately significant at the end of therapy, but virological, biochemical and complete response had a tendency to increase or accumulate gradually after the therapy. For three of the four trials that studied HBeAg-negative patients, the results are mostly applicable to HBeAg-negative CHB.

Effects of sex differences on constitutive nitric oxide synthase expression and activity in response to pressure overload in rats

Clinical studies have documented sex differences in left ventricular (LV) hypertrophy patterns, but the mechanisms are so far poorly defined. This study aimed to determine whether 1) severe pressure overload altered expression and/or activity of cardiac constitutive nitric oxide synthase (NOS1 and NOS3) and 2) these changes were modulated according to sex. Analyses were performed 0.4–20 wk after thoracic aortic constriction (TAC) in male and female Wistar rats. Male rats with TAC exhibited early signs of cardiac dysfunction, as shown by echocardiographic and LV end-diastolic pressure measurements, whereas females with TAC exhibited higher LV hypertrophy (+96% vs. males at 20 wk; P < 0.05). After TAC, cardiac NOS1 expression was rapidly induced (0.4 wk) and stable afterward in males ( P < 0.05 vs. sham groups), whereas it was delayed in females. Accordingly, specific NOS1 activity was increased by 2 wk in male rats with TAC (+122%; P < 0.001 vs. sham groups) and only by 20 wk in females (+220%; P < 0.001 vs. sham groups). NOS1 activity was correlated with NOS1 level. Regarding cardiac NOS3, expression was unaffected by TAC, and the decrease in activity observed at early and late times in male and female rats with TAC, respectively, is shown to be related to NOS3 allosteric regulator caveolin-1 level. The data demonstrated a unique sex-dependent regulation of the constitutive NOSs in response to TAC in rats; such a difference might play a role in the sex-dependent adaptability of the heart in response to pressure overload.

Sympathetic control of heart rate in nNOS knockout mice

Inhibition of neuronal nitric oxide synthase (nNOS) in cardiac postganglionic sympathetic neurons leads to enhanced cardiac sympathetic responsiveness in normal animals, as well as in animal models of cardiovascular diseases. We used isolated atria from mice with selective genetic disruption of nNOS (nNOS(-/-)) and their wild-type littermates (WT) to investigate whether sympathetic heart rate (HR) responses were dependent on nNOS. Immunohistochemistry was initially used to determine the presence of nNOS in sympathetic [tyrosine hydroxylase (TH) immunoreactive] nerve terminals in the mouse sinoatrial node (SAN). After this, the effects of postganglionic sympathetic nerve stimulation (1-10 Hz) and bath-applied norepinephrine (NE; 10(-8)-10(-4) mol/l) on HR were examined in atria from nNOS(-/-) and WT mice. In the SAN region of WT mice, TH and nNOS immunoreactivity was virtually never colocalized in nerve fibers. nNOS(-/-) atria showed significantly reduced HR responses to sympathetic nerve activation and NE (P < 0.05). Similarly, the positive chronotropic response to the adenylate cyclase activator forskolin (10(-7)-10(-5) mol/l) was attenuated in nNOS(-/-) atria (P < 0.05). Constitutive NOS inhibition with L-nitroarginine (0.1 mmol/l) did not affect the sympathetic HR responses in nNOS(-/-) and WT atria. The paucity of nNOS in the sympathetic innervation of the mouse SAN, in addition to the attenuated HR responses to neuronal and applied NE, indicates that presynaptic sympathetic neuronal NO does not modulate neuronal NE release and SAN pacemaking in this species. It appears that genetic deletion of nNOS results in the inhibition of adrenergic-adenylate cyclase signaling within SAN myocytes.

Differential role of S-nitrosylation and the NO-cGMP-PKG pathway in cardiac contractility

The role of nitric oxide (NO) in cardiac contractility is complex and controversial. Several NO donors have been reported to cause positive or negative inotropism. NO can bind to guanylate cyclase, increasing cGMP production and activating PKG. NO may also directly S-nitrosylate cysteine residues of specific proteins. We used the isolated rat heart preparation to test the hypothesis that the differential inotropic effects depend on the degree of NO production and the signaling recruited. SNAP (S-nitroso-N-acetylpenicillamine), a NO donor, increased contractility at 0.1, 1 and 10 microM. This effect was independent of phospholamban phosphorylation, was not affected by PKA inhibition with H-89 (N-[2((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide), but it was abolished by the radical scavenger Tempol (4-hydroxy-[2,2,4,4]-tetramethyl-piperidine-1-oxyl). However, at 100 microM SNAP reduced contractility, effect reversed to positive inotropism by guanylyl cyclase blockade with ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one), and abolished by PKG inhibition with KT5823, but not affected by Tempol. SNAP increased tissue cGMP at 100 microM, but not at lower concentrations. Consistently, a cGMP analog also reduced cardiac contractility. Finally, SNAP at 1 microM increased the level of S-nitrosylation of various cardiac proteins, including the ryanodine receptor. This study demonstrates the biphasic role for NO in cardiac contractility in a given preparation; furthermore, the differential effect is clearly ascribed to the signaling pathways involved. We conclude that although NO is highly diffusible, its output determines the fate of the messenger: low NO concentrations activate redox processes (S-nitrosylation), increasing contractility; while the cGMP-PKG pathway is activated at high NO concentrations, reducing contractility.

17beta-estradiol regulates constitutive nitric oxide synthase expression differentially in the myocardium in response to pressure overload

Estrogens [E(2)] exert direct and indirect effects that can modulate the development of cardiac disease. However, the precise mechanisms that are involved remain undefined. Our objective was to investigate whether E(2) affected the activity and expression of constitutive nitric oxide synthase (NOS) isoforms (NOS3 and NOS1) in cardiac hypertrophy induced by thoracic aortic constriction (TAC). Ovariectomized (Ovx) and nonovariectomized Wistar rats were subjected to TAC. Ovx animals received E(2) or placebo 3 wk after surgery for 11 wk. Afterward cardiac function and degree of left ventricular hypertrophy were assessed by echocardiography. NOS activity and expression were studied by biochemical techniques. TAC led to significant left ventricular hypertrophy (>90%) irrespective of hormonal status. Cardiac performance declined more in TAC+Ovx (-20%, P < 0.015) than in the two other TAC groups [TAC and TAC+Ovx+E(2)]. Total NOS activity decreased significantly in the Ovx groups. In response to TAC, total NOS activity increased whatever the E(2) status. Specific NOS3 activity dramatically decreased in the Ovx groups (-55%, P < 0.009) and was unaltered by TAC. By using coimmunoprecipitation assays, we showed that NOS3/caveolin-1 complexes negatively regulated NOS3 activity as a function of E(2) status. On the other hand, NOS1 expression and activity were markedly increased in hypertrophied myocardium (P < 0.003), irrespective of E(2) status. This study demonstrates a differential regulation of NOS expression and activity in response to pressure overload and E(2) status, the former being mainly involved in the induction of NOS1, whereas the latter regulated NOS3 activity and in turn cardiac function.

Atrial Glutathione Content, Calcium Current, and Contractility

Atrial fibrillation (AF) is characterized by decreased L-type calcium current (I(Ca,L)) in atrial myocytes and decreased atrial contractility. Oxidant stress and redox modulation of calcium channels are implicated in these pathologic changes. We evaluated the relationship between glutathione content (the primary cellular reducing moiety) and I(Ca,L) in atrial specimens from AF patients undergoing cardiac surgery. Left atrial glutathione content was significantly lower in patients with either paroxysmal or persistent AF relative to control patients with no history of AF. Incubation of atrial myocytes from AF patients (but not controls) with the glutathione precursor N-acetylcysteine caused a marked increase in I(Ca,L). To test the hypothesis that glutathione levels were mechanistically linked with the reduction in I(Ca,L), dogs were treated for 48 h with buthionine sulfoximine, an inhibitor of glutathione synthesis. Buthionine sulfoximine treatment resulted in a 24% reduction in canine atrial glutathione content, a reduction in atrial contractility, and an attenuation of I(Ca,L) in the canine atrial myocytes. Incubation of these myocytes with exogenous glutathione also restored I(Ca,L) to normal or greater than normal levels. To probe the mechanism linking decreased glutathione levels to down-regulation of I(Ca), the biotin switch technique was used to evaluate S-nitrosylation of calcium channels. S-Nitrosylation was apparent in left atrial tissues from AF patients; the extent of S-nitrosylation was inversely related to tissue glutathione content. S-Nitrosylation was also detectable in HEK cells expressing recombinant human cardiac calcium channel subunits following exposure to nitrosoglutathione. S-Nitrosylation may contribute to the glutathione-sensitive attenuation of I(Ca,L) observed in AF.

Effects of Oral Prednisone After Stenting in a Rabbit Model of Established Atherosclerosis

OBJECTIVES

The aim of this study was to compare the effects of systemic prednisone in combination with a bare-metal stent (BMS) or a paclitaxel-eluting stent (Taxus, Boston Scientific Corp., Natick, Massachusetts) on neointimal inhibition and vessel healing in an atherosclerotic rabbit model.

BACKGROUND

Inflammation plays a critical role in neointimal formation after coronary artery stenting. The efficacy of immunosuppressive doses of oral prednisone to inhibit in-stent neointimal proliferation was compared with BMS and with a commercially available paclitaxel-eluting stent (Taxus) in a rabbit model of established atherosclerosis.

METHODS

Bilateral iliac artery injury in atherosclerotic New Zealand White rabbits fed an atherogenic diet was followed by stent implantation. Animals randomly received Taxus stents, BMS (Express, Boston Scientific Corp.) and placebo, or BMS and oral prednisone (2.1 mg/kg/day for the first 7 days, followed by 1.4 mg/kg/day for 14 days and 0.7 mg/kg/day for 21 days). Stented arterial segments were harvested at 42 days and processed for light microscopy, immunohistochemistry, and organoid culture.

RESULTS

Compared with control subjects, prednisone-treated animals showed a 30% reduction in percent stenosis (p = 0.009), a 35% decrease in neointimal area (p < 0.003), and a 66% decrement in neointimal thickness (p < 0.001). Taxus stents also reduced all 3 parameters significantly (-34%, -39%, and -83%, respectively), but showed significantly more inflammatory cells and fibrin deposition and less endothelialization compared with the other 2 groups. Plaque burden was equal among groups, as shown by the identical stent and vessel area, and no remodeling was observed.

CONCLUSIONS

Systemic prednisone treatment and Taxus stents reduce neointimal formation compared with BMS. The extent of neointimal reduction is similar between prednisone- and Taxus stent-treated animals; however, Taxus stents resulted in a significantly greater delay in healing. Targeting of inflammatory pathways after percutaneous coronary intervention may be an efficacious way to prevent restenosis without the long-term risk of late thrombosis.

Analysis of the signals and mechanisms mediating nuclear trafficking of GATA-4. Loss of DNA binding is associated with localization in intranuclear speckles

Nucleocytoplasmic transport of GATA-4 is important in maintaining and regulating normal cardiogenesis and heart function. This report investigates the detailed mechanisms of GATA-4 nuclear transport. We characterized a nonclassical nuclear localization signal between amino acids 270 and 324 that actively transports GATA-4 into the nucleus of both HeLa cells and cardiac myocytes. Fine mapping studies revealed four crucial arginine residues within this region that mediate active transport predominantly through the nonclassical pathway via interaction with importin beta. These four residues were also essential for the DNA binding activity of GATA-4 and transcriptional activation of cardiac-specific genes. Interestingly, mutation of these residues not only inhibited DNA binding and gene transcription but also resulted in a preferential accumulation of the GATA-4 protein in distinct subnuclear speckles. A cardiac myocyte-specific, chromosome maintenance region 1-dependent nuclear export signal consisting of three essential leucine residues was also identified. The current study provides detailed information on the nuclear shuttling pathways of GATA-4 that represents an additional mechanism of gene regulation.

Thymosin Alpha 1: From Bench to Bedside

After the initial dramatic effects, observed in a Lewis lung carcinoma animal model, using a combination of thymosin alpha 1 (Talpha1) and interferon (IFN) after cyclophosphamide, a number of other preclinical models in mice (Friend erythroleukemia and B16 melanoma) and in rats (DHD/K12 colorectal cancer liver metastasis) have confirmed the efficacy of the combination therapy with Talpha1 and either IFN or IL-2 plus chemotherapy. These results provided the scientific foundation for the first clinical trials using Talpha1 in combination with BRMs and/or chemotherapy. Pivotal trials in advanced non-small cell lung cancer (NSCLC) and melanoma with Talpha1 and IFN-alpha low doses after cis-platinum or dacarbazine produced the first evidence of the high potentiality of this approach in the treatment of human cancer. The combination of Talpha1 and IFN-alpha was also used in patients affected by chronic B and C hepatitis including IFN-nonresponders and infected by precore mutants or genotype 1b. Further studies demonstrated additional biological activities clarifying the mechanism of action of Talpha1, partially explaining the synergism with IFN. It has been shown the capacity of activating infected dendritic cells through Toll-like receptor signaling, thus influencing the inflammation balance, and of increasing the expression of tumor, viral, and major histocompatibility complex (MHC) I antigens. Dose-response studies suggested the possibility of improving the efficacy of this molecule reducing the overall toxic. Based on these information two clinical trials are ongoing: a large phase II on advanced melanoma patients treated with Talpha1 at different doses after dacarbazine and a phase III one, on IFN-resistant hepatitis C virus (HCV) patients treated with a triple combination (IFN, ribavirin, and Talpha1).

Matrix metalloproteinases: influence on smooth muscle cells and atherosclerotic plaque stability

Atherosclerotic plaque rupture, with subsequent occlusive thrombosis, is the underlying cause of most cases of sudden cardiac death. Matrix metalloproteinases (MMPs) are thought to mediate the progression of stable atherosclerotic lesions to an unstable phenotype that is prone to rupture through the destruction of strength-giving extracellular matrix (ECM) proteins. Smooth muscle cells secrete and deposit ECM proteins and are, therefore, considered protective against atherosclerotic plaque destabilization. However, similar to inflammatory cells (e.g., macrophages), smooth muscle cells release numerous MMPs that are capable of digesting ECM proteins. Thus, the interaction of smooth muscle cells and MMPs in atherosclerotic plaques is complex and not fully understood. Recently, research into the roles of MMPs and their endogenous inhibitors (tissue inhibitors of metalloproteinases), and their effects on smooth muscle behavior during plaque destabilization has been aided by the development of reproducible animal models of plaque instability. A plethora of studies has demonstrated that MMPs directly modulate smooth muscle behavior with both beneficial and deleterious effects on atherosclerotic plaque stability, in addition to their canonical effects on ECM remodeling. Consequently, broad-spectrum MMP inhibition may inhibit plaque-stabilizing mechanisms, such as smooth muscle cell growth, while conversely retarding ECM destruction and subsequent rupture. Hence the development of selective MMP inhibitors, that spare inhibitory effects on smooth muscle cell function, may be useful therapies to prevent plaque rupture and in this regard MMP-12 appears to be a particularly attractive target.

New approach to prevent myocardial hypertrophy: the import blocking peptide

Calcineurin, a serine/threonine phosphatase, plays a crucial role in the development of myocardial hypertrophy. Calcineurin is a cytosolic phosphatase that dephosphorylates the nuclear factor of activated T cells (NFAT), a transcription factor. Until now, it has been postulated that dephosphorylated NFAT is shuttled into the nucleus. Recent evidence demonstrates that not only NFAT, but also calcineurin, is localized in the nucleus. Once calcineurin and NFAT enter the nucleus of cardiomyocytes, transcription of genes that are characteristic for myocardial hypertrophy (e.g., brain natriuretic peptide and atrial natriuretic peptide) occurs. Although the exact nuclear function of calcineurin remains unclear, its co-existence with NFAT is important for the full transcriptional activity of the calcineurin/NFAT signaling cascade. The principal effect of nuclear calcineurin is likely the prolonged nuclear retention period of NFAT. Potential effects of nuclear calcineurin include an antagonistic function to glycogen synthase kinase 3beta, which phosphorylates NFAT for its export out of the nucleus, or direct antagonization of the export of NFAT, catalyzed by the chromosome region maintenance 1, which would leave NFAT nuclear. The nuclear localization sequence (NLS) region at the amino acid sequence from position 172 to 183 of calcineurin Abeta is essential for shuttling calcineurin into the nucleus by importinbeta(1). A synthetic import blocking peptide (IBP) that mimics the nuclear localization sequence of calcineurin was generated. The NLS analog on IBP saturates the calcineurin binding site of importinbeta(1). This prevents the binding of calcineurin to importin and inhibits the nuclear shuttling of calcineurin. Inhibition of the calcineurin/importinbeta(1) interaction by competing synthetic peptides represents a new approach to the inhibition of the development of myocardial hypertrophy.

Hepatitis B virus genotype B is associated with better response to thymosin alpha1 therapy than genotype C

Hepatitis B virus (HBV) genotype has been reported to correlate with response to interferon treatment in several studies. The relationship between HBV genotype and thymosin alpha1 (T-alpha1) treatment is unknown. We retrospectively examine HBV genotypes, precore and core promoter mutations in patients treated with Talpha1 and analyse the correlation between complete response [alanine aminotransferase (ALT) normalization plus seroclearance of HBeAg and HBV-DNA] and HBV genotype. It consisted 98 patients with chronic hepatitis B randomly allocating to three groups: (i) T6 group (n = 32) received a 26-week course of Talpha1 1.6 mg two times a week; (ii) T12 group (n = 34) received the same regimen as T6 group, but Talpha1 therapy extended for 52 weeks; (iii) T0 group (n = 32) served as a control and was followed up for 18 months without specific treatment. Stepwise logistic regression analysis showed that genotype (OR, 3.747; 95% CI, 1.066-13.170; P = 0.039), precore mutation (OR, 6.285; 95% CI, 1.874-21.086; P = 0.003) and Talpha-1 treatment (OR, 12.045; 95% CI, 2.220-65.354; P = 0.004) as independent factors associated with complete response. The complete response of Talpha-1 therapy was higher in patients with genotype B compared to patients with genotype C (52%vs 24%; P = 0.036) and in patients with precore mutation (64%vs 19%; P = 0.002). In conclusion, genotype, presence of precore mutation and Talpha-1 therapy were independent predictors to complete response. Genotype B, compared to genotype C, is associated with a higher response rate to T-alpha1 therapy.

Efficacy of thymosin alpha-1 and interferon alpha in treatment of chronic viral hepatitis B: a randomized controlled study

AIM

To observe the efficiency and safety of thymosin-alpha1 treatment in patients with hepatitis B e antigen (HBeAg) and HBV DNA positive chronic hepatitis.

METHODS

Sixty-two patients were randomly divided into groups A and B. The patients in group A received subcutaneous injection of 1.6 mg thymosin-alpha1, twice a week (T-alpha1 group) for six months, and the patients in group B received 5 MU interferon alpha (IFN-alpha) each day for fifteen days, then three times weekly (IFN-alpha group) for six months. The results between two groups treated with and the group untreated with IFN-alpha which was followed up for 12 mo (historical control group consisting of 30 patients) were compared, and three groups were comparable between each other (P>0.05) at baseline (age, sex, clinical history, biochemical, and serological parameters).

RESULTS

At the end of treatment, complete response, which was defined as alanine aminotransferase (ALT) normalization and HBV DNA and HBeAg loss, occurred in 9 of 29 (31.0%) patients in the T-alpha1 group and in 15 of 33 (45.5%) patients in the IFN-alpha group (chi2=1.36, P>0.05). After a follow-up period of six months, a complete response was observed in 14 of 29 (48.3%) patients in the T-alpha1 group and in 9 of 33 (27.3%) patients in the IFN-alpha group (chi2=2.93, P>0.05). Compared with the results observed in the historical control (HC) group untreated with IFN-alpha which was followed up for 12 mo, the rate of complete response was significantly higher in IFN-alpha group at the end of therapy (1 of 30 vs 15 of 33, chi2=14.72, P<0.001) and in the T-alpha1 group at the end of follow-up (1 of 30 vs 14 of 29, chi2=15.71, P<0.001). In T-alpha1 and IFN-alpha treatment groups, the area under (the plasma concentration time) curve (AUC) of negative HBV DNA and HBeAg was 34%, 17%, 31% and 19% smaller than that in the HC group. By the end of the follow-up period, the proportions of ALT normalization and negative HBV DNA in the T-alpha1 group were significantly higher than those in the IFN-alpha and HC groups. The odds of ALT normalization and negative HBV DNA at the end of the follow-up was three-fold higher in the T-alpha1 group than in the IFN-alpha group. Unlike IFN-alpha, T-alpha1 was well tolerated by all patients, and no side effects appeared in T-alpha1 group.

CONCLUSION

The results suggest that a 6-mo course of T-alpha1 therapy is effective and safe in patients with chronic hepatitis B. T-alpha1 is able to reduce HBV replication in patients with chronic hepatitis B. Furthermore, T-alpha1 is better tolerated than IFN-alpha and can gradually induce more sustained ALT normalization and HBV DNA and HBeAg loss. However, a response rate of 48.3% is still less ideal. A more effective therapeutic approach warrants further study.

Liposomal plasmid DNA encoding human thymosin alpha and interferon omega potently inhibits liver tumor growth in ICR mice

AIM

To evaluate the potential therapeutic effect of liposomal gene delivery, genes encoding for human thymosin alpha1 (Talpha1) and interferon omega1 were injected via the tail vein into mice bearing a Hep-A-22 liver tumor.

METHODS

The cDNA of human Talpha1 and interferon omega1 were obtained by synthesis or reverse transcription-polymerase chain reaction (RT-PCR), respectively. Eukaryotic expressing vectors pIRES2, encoding Talpha1 and/or interferon omega1, were constructed and injected with liposome via the tail vein into ICR mice bearing a Hep-A-22 tumor. The potency of tumor inhibition was evaluated when three treated groups were compared with the group receiving the empty vector. Apoptosis of tumor cells was investigated by analyzing DNA fragmentation.

RESULTS

Only the group treated with dual-gene plasmid reached an eligible level of tumor inhibition (43%). The difference in tumor weight was statistically significant between the Talpha1 gene or the interferon omega1 gene treated groups and the control (P<0.05), and highly significant between the dual-gene treated group and the control (P<0.01). DNA ladder was observed in the tumor cells from the purpose gene treated groups but not from the control.

CONCLUSION

The dual-gene plasmid-liposome complex showed more potent inhibition than the single gene constructs on the growth of Hep-A-22 tumor cells in mice, which may be attributed to indirect and additive induction of apoptosis in tumor cells by increased expression of Talpha1 and interferon omega1.

CEACAMs: their role in physiology and pathophysiology

Carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) belong to a group of mammalian immunoglobulin-related glycoproteins. They are involved in cell–cell recognition and modulate cellular processes that range from the shaping of tissue architecture and neovascularization to the regulation of insulin homeostasis and T-cell proliferation. CEACAMs have also been identified as receptors for host-specific viruses and bacteria in mice and humans, respectively, making these proteins an interesting example of pathogen–host co-evolution. Forward and reverse genetics in the mouse now provide powerful novel models to elucidate the action of CEACAM family members in vivo.

Corneal integrins and their functions

Integrins were first described just over 20 years ago and have been studied in the cornea by many groups interested in how the cornea functions in health and disease. There are a minimum of 12 different integrin heterodimers reported to be expressed by the major resident cells of the cornea: the corneal and limbal epithelial cells, keratocytes/fibroblasts, and corneal endothelial cells. These different integrin heterodimers play important and varied roles in maintaining the cornea and organizing how its cells interact with their surrounding extracellular matrix to maintain corneal clarity. In this review, an overview of the discovery and functions of integrins is provided along with a description of the current state of our knowledge of this large family of important proteins. While we have learned a lot about corneal integrins over the past 20 years, there is still much to learn. Areas where gaps in our knowledge of integrin functions in the cornea are slowing our progress in understanding corneal diseases and dystrophies at a molecular level are highlighted.

Construction of retroviral vector of p125FAK specific ribozyme genes and its effects on BGC-823 cells

AIM: To construct the retroviral vector of p^125FAK specific ribozyme genes and to explore the feasibility of ribozyme in BGC-823 gene therapy in vitro.

METHODS: A hammerhead ribozyme DNA targeting p^125FAK mRNA from nt 1010 to nt 1032 was synthesized and recombinated into the retroviral vector pLXSN forming pLRZXSN recon. Using the lipofectin-mediated DNA transfection technique, pLRZXSN was introduced into BGC-823 cells. The effects of ribozyme on the growth of BGC-823 cells and apoptosis were studied by cell colony assay, flow cytometry (FCM), reverse transcriptase-polymerase chain reaction (RT-PCR), detection of DNA fragmentation and electron microscopy.

RESULTS: The number of BGC-823 cell colonies was inhibited by 56% after the cells were treated for 48 h. The cell proliferation was inhibited effectively by p^125FAK ribozyme and the inhibitory effect depended on the concentration and the time of incubation. The expression of p^125FAK mRNA and protein P¹²⁵ decreased sharply in BGC-823 cells treated with p^125FAK ribozyme. The characteristics of apoptosis, namely sub-G1 peak, DNA fragmentation and morphological changes, were revealed in BGC-823 cells treated with p^125FAK ribozyme.

CONCLUSION: p^125FAK ribozyme decreases p^125FAK gene expression and induces apoptosis of human gastric cancer cells in vitro.

Fibroblast migration after myocardial infarction is regulated by transient SPARC expression

Secreted protein, acidic, and rich in cysteine (SPARC) is thought to regulate cell matrix interaction during wound repair. We hypothesized that SPARC might promote migration via integrin-dependent mechanisms. The present study was designed to clarify the contribution of SPARC in the wound healing process after myocardial infarction (MI). Adult mice received a specific alpha(v) integrin inhibitor or vehicle through osmotic mini pumps. Mice of each group were either sham-operated or MI was induced. SPARC expression was investigated 2 days, 7 days, and 1 month after the surgical procedure. For migration assays, a modified Boyden chamber assay was used. A transient increase of SPARC levels was observed, starting at day 2 (2.55+/-0.21), day 7 (3.72+/-0.28), and 1 month (1.9+/-0.16) after MI. After 2 months, SPARC expression dropped back to normal levels compared to sham-operated hearts. Immunofluorescence analysis showed an increase of SPARC in the infarcted area 2 days after MI, a strong increase in the scar area 7 days after MI, and only low levels in the scar area 2 months after MI. Integrin alpha(v) inhibition abolished the up-regulation of SPARC. In vitro migration assays demonstrated that fibronectin-stimulated haptotaxis of fibroblasts was modulated by SPARC. This study provides evidence that SPARC is significantly up-regulated in the infarcted region after MI. This up-regulation is dependent on alpha(v) integrins. As SPARC is found to regulate fibroblast migration, it appears to play an important role in the injured myocardium with regard to healing and scar formation.

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The efficacy and safety of thymosin alpha-1 in Japanese patients with chronic hepatitis B; results from a randomized clinical trial

Thymalfasin (thymosin alpha-1; Talpha1) is a 28-amino acid polypeptide that has shown efficacy in the treatment of chronic hepatitis B virus (HBV) infection. The objective of this study was to evaluate the long-term, dose-related efficacy and safety of Talpha1 treatment in chronic hepatitis B patients with positive HBV-DNA and abnormally high alanine aminotransferase (ALT) levels. A total of 316 patients were randomized to receive either 0.8 or 1.6 mg of Talpha1 monotherapy for 24 weeks. At the end of the 72-week observation period (12 months after cessation of therapy), 36.4% of patients in the 1.6-mg treatment group achieved normalization of ALT, 30% achieved clearance of HBV-DNA by branched DNA vs 15% by transcription-mediated amplification, and 22.8% achieved clearance of HBe-antigen. Patients in the 0.8-mg treatment group achieved similar efficacy rates, although patients with advanced fibrosis demonstrated a significantly better response rate when treated with 1.6 mg of Talpha1 monotherapy vs 0.8 mg (as determined by intragroup analysis; patients were not stratified by liver biopsy). All adverse drug reactions were mild and most involved the fluctuation of liver enzymes, which was most likely related to the positive immune effects caused by the response to Talpha1 treatment. Adverse event incidence was similar in the 1.6- and 0.8-mg treatment groups. In conclusion, Talpha1 at doses of 0.8 and 1.6 mg exhibits long-term efficacy against hepatitis B with a good safety profile.

Emerging treatments in chronic hepatitis B

Although the management of chronic hepatitis B has improved over the last decade, none of the available therapeutic agents, IFN-alpha, lamivudine and adefovir dipivoxil, can achieve sustained off-therapy responses in most cases. Therefore, several newer, mainly antiviral and immunomodulatory agents, are being evaluated. Pegylated IFN-alpha(2a) has been shown to be more effective than lamivudine or standard IFN-alpha monotherapy in achieving post-therapy biochemical and virological responses, and is expected to be licensed soon for the treatment of chronic hepatitis B. Newer antiviral agents, such as entecavir and telbivudine, appear to be quite effective initially, but their sustained off-therapy response rates remain unknown. The preliminary data of monotherapies with immunomodulatory agents, or of combination therapies, have been rather disappointing. Long-term maintenance treatment with antiviral agent(s) with good safety and tolerability profiles and low resistance rates appears to be the most realistic future therapeutic option for most chronic hepatitis B patients.

Thymalfasin (thymosin-alpha 1) therapy in patients with chronic hepatitis B

Chronic hepatitis B virus (HBV) infection is a serious clinical problem because of its worldwide distribution and potential adverse sequelae. Globally, there are approximately 350 million people infected with chronic HBV, 75% of whom live in the Asia-Pacific region. Interferon-alfa and direct antiviral agents such as lamivudine and adefovir are effective in the therapy of chronic HBV infection but the efficacy is far from satisfactory, particularly in perinatally infected patients, patients with lower ALT levels and those with HBeAg-negative chronic hepatitis B. Thymalfasin (thymosin-alpha1) is an immunoregulatory agent able to enhance Th1 response. It has been shown to trigger maturational events in lymphocytes, to augment T-cell function, and to promote reconstitution of immune defects. Studies are underway in both monotherapy and combination therapy with thymalfasin and interferon and results are promising.

Effect of inducible nitric oxide synthesis inhibitor on CYP1A2 protein expression in BCG-immune liver damage in mice

AIM: To study the effect of nitric oxide production on CYP1A2 protein expression in immune liver damage induced by Mycobacterium Calmette-Guerin (BCG) in mice.

METHODS: Immune liver damage was induced by intravenous injection of BCG (125 mg/kg) for 2 weeks in vivo. The hepatic tissues injury was estimated by histopathological H-E staining. The protein expression of CYP2E1 and iNOS in hepatic tissues was determined by the method of immunohistochemistry. The correlation between iNOS inducing and liver injury degree was observered by the method of demi-quantification image analysis.

RESULTS: Two weeks after of BCG injection, granuloma was easily observed, and over-expression of iNOS protein was detected in the granulomas. The decrease of CYP1A2 protein expression was observed in mice hepatic tissues. Aminoguanidine, a selective iNOS inhibitor, significantly inhibited iNOS protein expression, and reversed down-regulation of CYP1A2 protein induced by BCG-immune liver damage in mice.

CONCLUSION: Under the BCG-stimulated condition, nitric oxide production participates in the down-regulation of CYP1A2 protein expression induced by immune hepatic injury in mice.

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Rapid and high throughput detection of HBV YMDD mutants with fluorescence polarization

AIM: To develop a simple and rapid detection of HBV gene variants and prediction of lamivudine-resistance in patients.

METHODS: Initially, plasmids harboring the wild-type or mutant HBV DNA fragments were used in a model system. The technique was then applied to clinical samples for an analysis of YMDD mutations. The sera were extracted from chronic hepatitis patients who had received lamivudine treatment for more than one year. P region gene of HBV was amplified by polymerase chain reaction. The excess primers and dNTPs in PCR products were removed by cleaning-up reagents. Template-directed dye-terminator incorporation reaction was performed and R110 or TAMRA labeled acyclo-terminator was added on the 3’ end of TDI-primer specifically. Fluorescence polarization value was measured with Victor 2 multilabel counter and the genotypes of HBV were analyzed.

RESULTS: The YMDD genotypes in recombined positive plasmid and 56 serum samples of HBV infected patients were analyzed by using our TDI-FP method and the specificity and sensitivity were confirmed by DNA sequencing. Five of 56 serum samples showed YVDD phenotype (9%), including 1 YMDD and YVDD mixed infection. Four of 56 showed YIDD phenotype (7.1%).

CONCLUSION: This is a simple, rapid, low cost and high throughput assay to detect HBV polymerase gene variants and suitable for large-scale screening and prediction of the lamivudine-resistance in clinical samples.

Correlation of splenic ultrasonography, HBV e system and AFP levels in hepatitis B with hepatic fibrosis and carcinogenesis

AIM

To clarify the relationship of splenic ultrasonography in liver fibrosis and carcinogenesis associated with hepatitis B, the spontaneous conversion of HBeAg to Anti-HBe and AFP level.

METHODS

The indexes of spleen ultrasonography of liver fibrosis along with carcinogenensis related with hepatitis B, positive rates of HBeAg or Anti-HBe and AFP levels were compared in different liver fibrosis stages and hepatocellular carcinoma (HCC) related with hepatitis B.

RESULTS

The lengths of spleen (mm) in stages of liver fibrosis S1, S2, S3, S4 and HCC with hepatitis B were 104.6±13.1, 108.7±13.6, 110.5±15.4, 123.0±16.8 and 116.9±28.2, respectively; differences of splenic length between group S4 and groups S1, S2 or S3 were significant statistically (P<0.05). The thicknesses of spleen (mm) in groups S1, S2, S3, S4 and HCC were 35.2±6.3, 37.0±7.7, 37.8±9.6, 43.3±10.8 and 40.811.2, respectively; difference in splenic thickness between group S4 and S1 was significant statistically (P<0.05). The widths of splenic vein (mm) in groups S1, S2, S3, S4 and HCC were 6.0±1.4, 6.5±1.4, 6.8±1.7, 7.8±1.7 and 6.82.6 respectively; there were differences among groups S4 and S1 or S2 (P<0.05) statistically. The positive rates of HBeAg were 92%(23/25), 75.6%(31/41), 68.8%(22/32), 51.9%(14/27) and 13.5%(5/37); and the positive rates of anti-HBe were 4%(1/25), 19.5%(8/41), 25%(8/32), 33.3%(9/27) and 70.3%(26/37) in group S1, S2, S3, S4 and HCC, respectively; difference between each two group among group S1, S2, S3, S4 and HCC was significant(P<0.05). The AFP levels(μg/L) were 11.0±6.7, 49.4±74.5, 112.11±59.0, 179.32±0.8 and 367.46±17.1 in group S1, S2, S3, S4 and HCC, respectively; there were differences among groups HCC and S1 or S2; S4, S3 or S2 and S1 (P<0.05), statistically.

CONCLUSION

The length and thickness of spleen and width of splenic vein were increased as the deterioration of severity of hepatic fibrosis. The length of spleen is more sensitive in indicating the severity of liver fibrosis. Both AFP level and splenic size were elevated as the increase rate of spontaneous conversion from HBeAg to anti-HBe. The risk of hepatocellular carcinoma associated with hepatitis B exists in any stages of liver fibrosis.

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Detection of HBV, HCV and HBV YMDD mutants by DNA microarray

AIM: To investigate the effect of DNA microarray in detection of hepatitis B virus (HBV), hepatitis C virus (HCV) and HBV YMDD mutants.

METHODS: HBV and HCV in 40 serum samples were detected by mixed microarray and quantitative determination method as well; 20 serum samples from patients with hepatitis B treated with lamivudine were detected by microarray loaded HBV YMDD mutants gene, and were simultaneously tested with mismatched PCR and DNA sequencing for comparison.

RESULTS: The coincident rate of mixed microarray and quantitative determination of HBV DNA was 85% (34/40). The detectable rate of HBV by mixed microarray was 83% (19/23); 2 of 17 samples showed false positive reaction. The coincident rate of mixed microarray and HCV RNA quantitative determination was 85% (34/40). The detectable rate of HCV by mixed microarray was 58% (7/12). One of 28 samples showed false positive reaction. The coincident rate of HBV YMDD mutants microarray and mismatched PCR was 70% (14/20). Mixed infection of wild and mutant HBV or different mutants were detected by microarray.

CONCLUSION: Mixed microarray has high sensitivity and low non-specificity in detection of HBV, but has lower sensitivity and higher specificity in detection of HCV. Detection of HBV YMDD mutants and mixed infection with microarray had higher sensitivity and specificity.

Changes in serum and histology of patients with chronic hepatitis B after interferon alpha-2b treatment

AIM: Chronic hepatitis B is a serious health problem. Interferon has long been used to treat Chronic hepatitis B. To evaluate the effects of interferon on chronic hepatitis B better, we designed the study to investigate the changes in sera and liver histology of patients with chronic hepatitis B after interferon alpha-2b treatment.

METHODS: Twenty-four patients with chronic hepatitis B were enrolled in this study. They all received interferon alpha-2b treatment as following: 3 million units, i.m. t.i.w., for 18 weeks. Sera of all patients were obtained respectively for evaluation of ALT, HBsAg, HBcAg, HBeAg, HBV DNA and TIMP-1 before and after interferon treatment, also a liver biopsy pre- and post-treatment was performed for comparison of HAI, HBsAg, HBcAg, HBeAg, TIMP-1 and activated HSC in the liver tissue.

RESULTS: Patients who had normalization of serum ALT and seroconversion of HBeAg and/or HBV DNA (blot hybridization) after treatment were defined as responders. The response rate in this study group was 37.5% (7/24). Compared to pretreatment, the serum HBV DNA and TIMP-1 decreased significantly (P < 0.05), so did the HAI, HBcAg, HBeAg, TIMP-1 and activated HSC (P < 0.05).

CONCLUSION: The significant decrease in HBV DNA in sera, the seroconversion of HBeAg, and the decrease of viral expression in liver indicated that interferon alpha-2b treatment can inhibit viral replication. The normalization of ALT in sera and the improvement of HAI in liver showed that interferon alpha-2b can improve the liver histology of patients with chronic hepatitis B. At the same time, interferon alpha-2b treatment can reduce the TIMP-1 in serum and liver and decrease the number of activated HSC, which may allievate or inhibit hepatic fibrosis. Although the response rate was unsatisfactory, interferon play a benefical role on patients with chronic hepatitis B in other respects. We still need further studies to improve the therapy effects.

Hepatoprotective role of ganoderma lucidum polysaccharide against BCG-induced immune liver injury in mice

AIM: To examine the effect of ganoderma lucidum polysaccharide (GLP) on the immune liver injury induced by BCG infection, and investigate the relationship between degrees of hepatic damage and NO production in mice.

METHODS: Immune hepatic injury was markedly induced by BCG-pretreatment (125 mg·kg^-1, 2-week, iv) or by BCG-pretreatment plus lipopolysaccharide (LPS, 125 μg·kg^-1, 12-hour, iv) in mice in vivo. Hepatocellular damage induced by BCG-pretreated plus inflammatory cytokines mixture (CM), which was included TNF-α, IL-1β, IFN-γ and LPS in culture medium in vitro. Administration of GLP was performed by oral or incubating with culture medium at immune stimuli simultaneity. Liver damage was determined by activity of alanine aminotransferase (ALT) in serum and in hepatocytes cultured supernatant, by liver weight changes and histopathological examination. NO production in the cultured supernatant was determined by the Griess reaction. Moreover, inducible nitric oxide synthase (iNOS) protein expression was also examinated by immunohistochemical method.

RESULTS: Immune hepatic injury was markedly induced by BCG or BCG plus inflammatory cytokines in BALB/c mice in vivo and in vitro. Under BCG-stimulated condition, augment of the liver weight and increase of the serum/supernatant ALT level were observed, as well as granuloma forming and inflammatory cells soakage were observed by microscopic analysis within liver tissues. Moreover, NO production was also increased by BCG or/and CM stimuli in the culture supernatant, and a lot of iNOS positive staining was observed in BCG-prestimulated hepatic sections. Application of GLP significantly mitigated hepatic tumefaction, decreased ALT enzyme release and NO production in serum/supernatant, improved the pathological changes of chronic and acute inflammation induced by BCG-stimuli in mice. Moreover, the immunohistochemical result showed that GLP inhibited iNOS protein expression in BCG-immune hepatic damage model.

CONCLUSION: The present study indicates that NO participates in immune liver injury induced by Mycobacterium bovis BCG infection. The mechanisms of protective roles by GLP for BCG-induced immune liver injury may be due to influence NO production in mice.