Virological response and safety of 24-week telaprevir alone in Japanese patients infected with hepatitis C virus subtype 1b

Hepatitis C virus (HCV) subtype 1b, which infects approximately 70% of Japanese carriers, is likely to be more eradicable by a telaprevir regimen than subtype 1a because of the higher genetic barrier of Val(36) and Arg(155) substitutions. The aims of this exploratory study were to evaluate the virological response and safety of 24-week oral administration of telaprevir alone in chronic HCV subtype 1b infection. Fifteen treatment-naïve patients were treated with telaprevir 750 mg every 8 h for 24 weeks. All patients were Japanese whose median age was 58.0 years (range: 45-68), and six patients (40%) were men. Median baseline HCV RNA level was 6.80 log(10) IU/mL (range: 3.55-7.10). The HCV RNA levels decreased to undetectable in five patients (33%) within 8 weeks. Three patients (20%) with negative HCV RNA by Week 4 achieved end of treatment response. One patient (7%) who achieved sustained virological response had a low baseline viraemia of 3.55 log(10) IU/mL. Most of the adverse events including anaemia and skin disorders were mild to moderate. Developed variants were T54A and A156V/T/F/Y with or without secondary substitutions rather than V36M ± R155K. Telaprevir alone for 24 weeks in Japanese patients with HCV subtype 1b resulted in an sustained viral response rate of 7% (1/15) and was well tolerated for 24 weeks. These results will support the implementation of further studies on oral combination of telaprevir with other direct-acting antiviral agents in patients infected with HCV subtype 1b.

Determination of accurate 1H positions of an alanine tripeptide with anti-parallel and parallel β-sheet structures by high resolution 1H solid state NMR and GIPAW chemical shift calculation

The accurate (1)H positions of alanine tripeptide, A(3), with anti-parallel and parallel β-sheet structures could be determined by highly resolved (1)H DQMAS solid-state NMR spectra and (1)H chemical shift calculation with gauge-including projector augmented wave calculations.

Safety, pharmacokinetics and resistant variants of telaprevir alone for 12 weeks in hepatitis C virus genotype 1b infection

BACKGROUND

Telaprevir in combination with peginterferon and ribavirin is a promising advancement in chronic hepatitis C treatment. However, the safety, tolerability, pharmacokinetics and antiviral profiles of telaprevir alone beyond 2 weeks have not been studied.

METHODS

In a phase 1b study in Japan, 10 treatment-naïve patients infected with hepatitis C virus genotype 1b with high viral load (>5 log(10) IU/mL) received telaprevir 750 mg every 8 h (q8h) for 12 weeks. We examined the safety, tolerability, pharmacokinetics, hepatitis C virus (HCV) RNA levels and resistant variants of telaprevir.

RESULTS

Neither serious adverse events nor discontinuations of study drug owing to an adverse event occurred. The most common adverse drug reactions were rash (80%) and anaemia (70%). Telaprevir concentration reached its steady state within 2 days after the first administration without abnormal accumulation. Telaprevir alone provided potent antiviral activity: a median log(10) decrease of 2.325 at 16 h and 5.175 on Day 14. During the treatment, HCV RNA levels at the nadir were below the limit of the quantification in seven patients and undetectable in three of 10 patients. Viral breakthrough associated with mainly Ala(156) -substituted variants occurred in eight patients, and only one patient showed end-of-treatment response. The selected variants reverted to the wild-type during the 24-week follow-up period.

CONCLUSION

Telaprevir alone was well tolerated at 750 mg q8h for up to 12 weeks. The safety profile and emergence of resistant variants of genotype 1b under telaprevir monotherapy for 12 weeks will become increasingly important in evaluating an oral combination of telaprevir with other direct-acting antiviral agents.

Aliskiren inhibits intracellular angiotensin II levels without affecting (pro)renin receptor signals in human podocytes

BACKGROUND

A direct renin inhibitor (DRI) had a benefit in decreasing albuminuria in type 2 diabetic patients having already been treated with angiotensin (Ang) II type 1 receptor blocker (ARB), suggesting that aliskiren may have another effect other than blockade of the traditional renin-angiotensin system (RAS). Recently, prorenin bound to (pro)renin receptor ((P)RR) was found and shown to evoke two pathways; the generation of Ang peptides and the receptor-dependent activation of extracellular signal-related protein kinase (ERK). Because (P)RR is present in the podocytes, a central component of the glomerular filtration barrier, we hypothesized that aliskiren influences the (P)RR-induced two pathways in human podocytes.

METHODS

Human podocytes were treated with 2 nmol/l prorenin in the presence and absence of an angiotensin-converting enzyme inhibitor (ACEi) imidaprilat, an ARB candesartan, a DRI aliskiren, or the siRNA knocking down the (P)RR mRNA and the intracellular AngII levels and the phosphorylation of ERK were determined.

RESULTS

The expression of (P)RR mRNA of human podocytes was unaffected by the treatment with RAS inhibitors, but decreased by 69% with the siRNA treatment. The basal levels of intracellular AngII and the prorenin-induced increase in intracellular AngII were significantly reduced by aliskiren and siRNA treatment, compared with imidaprilat and candesartan. The prorenin-induced ERK activation was reduced to control level by the siRNA treatment, but it was unaffected by imidaprilat, candesartan, or aliskiren.

CONCLUSIONS

Aliskiren is the most potent inhibitor of intracellular AngII levels of human podocytes among RAS inhibitors, although it is incapable of inhibiting the (P)RR-dependent ERK phosphorylation.

Changes in Fungicide Resistance Frequency and Population Structure of Pyricularia oryzae after Discontinuance of MBI-D Fungicides

The changes in fungicide resistance frequency and population structure of the rice blast fungus Pyricularia oryzae were monitored after the discontinuance of melanin biosynthesis inhibitor targeting scytalone dehydratase (MBI-D) fungicides use in Saga Prefecture, Japan. After discontinuance in 2003, the frequency of resistant isolates decreased from 71.8% in 2002 to 25% in 2003, and became undetectable in 2007. The initial marked decrease was due to a decline of isolates possessing the predominant haplotype, although the haplotypic diversity among resistant isolates remained high from 2003 to 2005. These results revealed that resistant isolates were less fit in comparison with sensitive isolates in the absence of MBI-D fungicide pressure under field conditions. Pairwise F_ST values indicated that the change in population structure after MBI-D discontinuance was explainable by a rapid change in the proportions of resistant and sensitive subpopulations. Depending upon the existence of fitness cost and rapid changes in population structure, it may be possible to reintroduce MBI-D fungicides in areas where resistance has already developed, although we speculate that fitness cost related to MBI-D resistance may be small based on our present results and previous findings.

Occult hepatitis B virus infection increases hepatocellular carcinogenesis by eight times in patients with non-B, non-C liver cirrhosis: a cohort study

An impact of serum hepatitis B virus (HBV) DNA on hepatocarcinogenesis has not been investigated in a cohort of patients with non-B, non-C cirrhosis. Eighty-two consecutive Japanese patients with cirrhosis, who showed negative hepatitis B surface antigen and negative anti-hepatitis C virus, were observed for a median of 5.8 years. Hepatitis B virus core (HBc) region and HBx region were assayed with nested polymerase chain reaction. Both of HBc and HBx DNA were positive in 9 patients (11.0%) and both were negative in 73. Carcinogenesis rates in the whole patients were 13.5% at the end of the 5th year and 24.6% at the 10th year. The carcinogenesis rates in the patients with positive DNA group and negative DNA group were 27.0% and 11.8% at the end of the 5th year, and 100% and 17.6% at the 10th year, respectively (P = 0.0078). Multivariate analysis showed that men (P = 0.04), presence of HBc and HBx DNA (hazard ratio: 8.25, P = 0.003), less total alcohol intake (P = 0.010), older age (P = 0.010), and association of diabetes (P = 0.005) were independently associated with hepatocellular carcinogenesis. Existence of serum HBV DNA predicted a high hepatocellular carcinogenesis rate in a cohort of patients with non-B, non-C cirrhosis.

Expression of distinct alpha 1-adrenoceptor phenotypes in the iris of pigmented and albino rabbits

BACKGROUND AND PURPOSE

The expression of multiple pharmacological phenotypes including alpha(1L)-adrenoceptor has recently been reported for alpha(1)-adrenoceptors. The purpose of the present study was to identify alpha(1)-adrenoceptor phenotypes in the irises of pigmented and albino rabbits.

EXPERIMENTAL APPROACH

Radioligand binding and functional bioassay experiments were performed in segments or strips of iris of pigmented and albino rabbits, and their pharmacological profiles were compared.

KEY RESULTS

[(3)H]-silodosin at subnanomolar concentrations bound to intact segments of iris of pigmented and albino rabbits at similar densities (approximately 240 fmol x mg(-1) protein). The binding sites in the iris of a pigmented rabbit were composed of a single component showing extremely low affinities for prazosin, hydrochloride [N-[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro-alpha,alpha-dimethyl-1H-indole-3-ethamine hydrochloride (RS-17053)] and 5-methylurapidil, while two components with high and low affinities for prazosin, RS-17053 and 5-methylurapidil were identified in irises from albino rabbits. In contrast, specific binding sites for [(3)H]-prazosin were not clearly detected because a high proportion of non-specific binding and/or low affinity for prazosin occurred. Contractile responses of iris dilator muscle to noradrenaline were antagonized by the above ligands, and their antagonist affinities were consistent with the binding estimates at low-affinity sites identified in both strains of rabbits.

CONCLUSIONS AND IMPLICATIONS

A typical alpha(1L) phenotype with extremely low affinity for prazosin is exclusively expressed in the iris of pigmented rabbits, while two distinct phenotypes (alpha(1A) and alpha(1L)) with high and moderate affinities for prazosin are co-expressed in the iris of albino rabbits. This suggests that a significant difference in the expression of phenotypes of the alpha(1)-adrenoceptor occurs in the irises between the two strains of rabbits.

Development of simple sequence repeat markers for Japanese isolates of Magnaporthe grisea

We developed nine simple sequence repeat (SSR) markers useful for differentiating Japanese isolates of Magnaporthe grisea through a bioinformatic approach. Repeat sequences in the genome of M. grisea were identified by a Tandem Repeat Finding program. Length polymorphisms at 28 loci were examined, nine of which were selected on the basis of detected polymorphisms. These nine SSR markers showed a Nei's gene diversity ranging from 0.23 to 0.91 among 48 field isolates of two natural populations. These SSR markers are well suited for M. grisea epidemiology and population genetics.

Identification of alpha 1L-adrenoceptor in mice and its abolition by alpha 1A-adrenoceptor gene knockout

BACKGROUND AND PURPOSE

The alpha(1L)-adrenoceptor has pharmacological properties that distinguish it from three classical alpha(1)-adrenoceptors (alpha(1A), alpha(1B) and alpha(1D)). The purpose of this was to identify alpha(1L)-adrenoceptors in mice and to examine their relationship to classical alpha(1)-adrenoceptors.

EXPERIMENTAL APPROACH

Radioligand binding and functional bioassay experiments were performed on the cerebral cortex, vas deferens and prostate of wild-type (WT) and alpha(1A)-, alpha(1B)- and alpha(1D)-adrenoceptor gene knockout (AKO, BKO and DKO) mice.

KEY RESULTS

The radioligand [(3)H]-silodosin bound to intact segments of the cerebral cortex, vas deferens and prostate of WT, BKO and DKO but not of AKO mice. The binding sites were composed of two components with high and low affinities for prazosin or RS-17053, indicating the pharmacological profiles of alpha(1A)-adrenoceptors and alpha(1L)-adrenoceptors. In membrane preparations of WT mouse cortex, however, [(3)H]-silodosin bound to a single population of prazosin high-affinity sites, suggesting the presence of alpha(1A)-adrenoceptors alone. In contrast, [(3)H]-prazosin bound to two components having alpha(1A)-adrenoceptor and alpha(1B)-adrenoceptor profiles in intact segments of WT and DKO mouse cortices, but AKO mice lacked alpha(1A)-adrenoceptor profiles and BKO mice lacked alpha(1B)-adrenoceptor profiles. Noradrenaline produced contractions through alpha(1L)-adrenoceptors with low affinity for prazosin in the vas deferens and prostate of WT, BKO and DKO mice. However, the contractions were abolished or markedly attenuated in AKO mice.

CONCLUSIONS AND IMPLICATIONS

alpha(1L)-Adrenoceptors were identified as binding and functional entities in WT, BKO and DKO mice but not in AKO mice, suggesting that the alpha(1L)-adrenoceptor is one phenotype derived from the alpha(1A)-adrenoceptor gene.

Increased expression of cyclooxygenase-2 in the renal cortex of human prorenin receptor gene-transgenic rats

Increased macula densa cyclooxygenase-2 (COX-2) is observed in diabetic rats and may contribute to hyperfiltration states. However, the signals mediating increased COX-2 expression in diabetic rats remain undetermined. We recently found that non-proteolytic activation of prorenin by site-specific binding proteins, such as prorenin receptor, plays a pivotal role in the development of diabetic nephropathy. The present study was designed to determine the contribution of prorenin receptor to renal cortical COX-2 expression. The COX-2 mRNA and protein levels of six 4-week-old male wild-type rats and six human prorenin receptor gene-transgenic (hProRenRcTg) rats were measured by real-time polymerase chain reaction methods, Western blotting, and immunohistochemistry, and compared. There were no differences between the two groups in arterial pressure measured by telemetry, urinary sodium excretion, or renal levels of rat prorenin receptor mRNA. The renal cortical COX-2 mRNA levels of the hProRenRcTg rats were significantly higher than those of the wild-type rats, and the renal cortical COX-2 protein levels were also higher in hProRenRcTg rats than in the wild-type rats. Immunohistochemical analysis revealed that COX-2 immunostaining was predominantly present in the macula densa cells, and significantly more COX-2-positive cells were present in the hProRenRcTg rats than in the wild-type rats. In addition, COX-2 inhibition with NS398 significantly decreased renal cortical blood flow in the hProRenRcTg rats but not in the wild-type rats. These results strongly suggest that human prorenin receptor directly or indirectly contributes to the regulation of renal cortical COX-2 expression.

Immunological control of methicillin-resistant Staphylococcus aureus (MRSA) infection in an immunodeficient murine model of thermal injuries

Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), is a major cause of sepsis in patients who are immunosuppressed by their burns. In this study, an immunological regulation of MRSA infection was attempted in a mouse model of thermal injury. SCIDbg mice were resistant to MRSA infection, while SCIDbgMN mice (SCIDbg mice depleted of neutrophils and macrophages (Mphi)) were susceptible to the same infection. Also, thermally injured SCIDbg mice were shown to be susceptible to MRSA infection. On the other hand, the resistance of SCIDbgMN mice to the infection was completely recovered after an inoculation with Mphi from normal mice. However, anti-MRSA resistance was not shown in SCIDbgMN mice inoculated with Mphi from thermally injured mice. Mphi from MRSA-infected thermally injured mice were identified as alternatively activated Mphi, and Mphi from MRSA-infected unburned mice were characterized as classically activated Mphi. Mphi from thermally injured SCIDbg mice previously treated with 2-carboxyethylgermanium sesquioxide (Ge-132) protected SCIDbgMN mice against MRSA infection. Ge-132 has been described as an inhibitor of alternatively activated Mphi generation. These results suggest that MRSA infection in thermally injured patients is controlled immunologically through the induction of anti-MRSA effector cells and elimination of burn-associated alternatively activated Mphi, which are cells that inhibit the generation of classically activated Mphi.

Serum prorenin levels and diabetic retinopathy in type 2 diabetes: new method to measure serum level of prorenin using antibody activating direct kinetic assay

AIM

To investigate the serum levels of prorenin and its correlation with the severity of diabetic retinopathy (DR).

METHODS

248 patients with diabetes and 108 control subjects were divided into four groups: no-DR (n = 146), no proliferative diabetic retinopathy (no-PDR) (n = 78), PDR (n = 24), and controls (n = 108). Serum levels of prorenin from all subjects were measured using the new antibody activating direct kinetic (AAD-PR) assay. The serum prorenin levels were compared among the groups.

RESULTS

The serum levels of prorenin in the control, no-DR, no-PDR, and PDR groups, respectively, were 109.1 (66.1), 194.6 (160.4), 271.5 (220.3), and 428.4 (358.4) pg/ml (mean (SD)). Prorenin in the PDR group was remarkably high compared with the control and no-DR groups (p<0.0001) and with the no-PDR group (p = 0.002). Serum levels of prorenin increased with increasingly severe retinopathy. No correlation was found between the prorenin level and the duration of disease or HbA(1c).

CONCLUSIONS

The serum levels of prorenin in patients with PDR were found to be markedly high using the AAD-PR assay. Increased levels of prorenin in diabetes may have an important role in the pathogenesis of DR.

Favorable outcomes with tacrolimus in two patients with refractory interstitial lung disease associated with polymyositis/dermatomyositis

Two cases of progressive interstitial lung disease associated with polymyositis/dermatomyositis are presented. Both patients were refractory to conventional therapy with high-dose corticosteroids, cyclosporine, and intermittent pulse cyclophosphamide, and thus a therapeutic trial of tacrolimus was instituted. Tacrolimus was markedly effective in achieving subjective, laboratory and radiographic improvement in both patients.

Single nucleotide polymorphism of the MxA gene promoter influences the response to interferon monotherapy in patients with hepatitis C viral infection

The biological activity of interferon (IFN) is mediated by the induction of intracellular antiviral proteins, such as 2'-5' oligoadenylate synthetase, dsRNA-activated protein kinase and MxA protein. Among these, MxA protein is assumed to be the most specific surrogate parameter for IFN action. This study was performed to elucidate whether a single nucleotide polymorphism (SNP) (G/T at nt-88) in the promoter region of the MxA gene influences the response to IFN therapy in patients with chronic hepatitis C virus (HCV) infection. Polymorphisms of the MxA gene in 235 HCV patients were determined by polymerase chain reaction-restriction fragment length polymorphism. The frequency of SNP was compared between sustained-responders (n = 78) and nonresponders (n = 157), as determined by biochemical and virological responses to IFN. Multivariate analysis showed that among all patients, HCV genotype, HCV RNA level and the SNP of the MxA gene were independent and significant determinants of the outcome of IFN therapy [odds ratio 3.8 (95% confidence interval 2.0-7.0), P < 0.0001; 0.27 (0.15-0.50), P < 0.0001; 1.8 (1.0-3.4), P = 0.0464, respectively]. Furthermore, among patients with a low viral load (< or =2.0 Meq/mL), MxA-T-positive patients were more likely to show a sustained response compared with MxA-T-negative patients [2.87 (1.3-6.3); 62%vs 36%; P = 0.0075]. Our findings suggested that the SNP of the MxA gene is one of the important host factors that independently influences the response to IFN in patients with chronic HCV infection, especially those with a low viral load.

Wild-type precore and core promoter sequences in patients with acute self-limited or chronic hepatitis B

BACKGROUND

Mutations in the precore region and core promoter were compared between patients with acute and chronic hepatitis B.

METHODS

There were 69 patients with acute self-limited hepatitis B and 210 with chronic hepatitis B who had been followed for > 15 years. The hepatitis B virus (HBV) of genotypes A, B and C was detected in 14 (23%), 8 (13%) and 28 (45%) of the patients with acute self-limited hepatitis, respectively, in contrast to 11 (5%), 25 (12%) and 167 (80%) of those with chronic hepatitis.

RESULTS

At presentation, hepatitis B e antigen (HBeAg) in serum was the more common (82% versus 65%, P < 0.05), and the wild-type sequences of the precore region (100% versus 74%, P < 0.001) and core promoter (88% versus 36%, P < 0.00001) were more frequent in the 50 patients with acute self-limited hepatitis than the 203 patients with chronic hepatitis B who were infected with HBV of genotype A, B or C. Wild-types of both the precore region and core promoter persisted in acute self-limited hepatitis, while they decreased from 28% to 10% in chronic hepatitis over the course of > 15 years.

CONCLUSION

HBV with the wild-type sequences of the precore region and core promoter prevails in patients with acute self-limited hepatitis, unlike in patients with chronic hepatitis.

Industry forum: Progress in pursuit of therapeutic A2A antagonists: The adenosine A2A receptor selective antagonist KW6002: Research and development toward a novel nondopaminergic therapy for Parkinson's disease

Research and development of the adenosine A2A receptor selective antagonist KW6002 have focused on developing a novel nondopaminergic therapy for Parkinson's disease (PD). Salient pharmacologic features of KW6002 were investigated in several animal models of PD. In rodent and primate models, KW6002 provides symptomatic relief from parkinsonian motor deficits without provoking dyskinesia or exacerbating existing dyskinesias. The major target neurons of the A2A receptor antagonist were identified as GABAergic striatopallidal medium spiny neurons. A possible mechanism of A2A receptor antagonist action in PD has been proposed based on the involvement of striatal and pallidal presynaptic A2A receptors in the "dual" modulation of GABAergic synaptic transmission. Experiments with dopamine D2 receptor knockout mice showed that A2A receptors can function and anti-PD activities of A2A antagonists can occur independent of the dopaminergic system. Clinical studies of KW6002 in patients with advanced PD with L-dopa-related motor complications yielded promising results with regard to motor symptom relief without motor side effects. The development of KW6002 represents the first time that a concept gleaned from A2A biologic research has been applied successfully to "proof of concept" clinical studies. The selective A2A antagonist should provide a novel nondopaminergic approach to PD therapy.

Duodenal wall cysts may be derived from a ductal component of ectopic pancreatic tissue

AIMS

To clarify the mechanism of origin of duodenal wall cysts in patients with chronic pancreatitis, developing into duodenal stenosis.

METHODS AND RESULTS

Specimens from 12 pancreatoduodenectomized patients with chronic pancreatitis and 51 controls were studied histopathologically and immunohistochemically. Variously shaped cystic lesions, averaging about 15 mm in diameter, were found in the duodenum in six of the 12 patients with chronic pancreatitis, but were not observed in the controls. Each case had an average of two cysts, which were located mainly in the muscularis propria of the duodenum with or without submucosal or extraduodenal-peripancreatic extensions. The inner part of the cyst wall consisted of a moderate rim of granulation tissue, with both myofibroblasts and smooth muscle proliferation in the tissue surrounding the cyst and the submucosal layer of the duodenum, occasionally accompanied by an epithelial lining. A ductal structure in the muscularis propria of the duodenum, possibly a ductal component of ectopic pancreatic tissue, was found in five of the six cases. Some of these structures showed cystic changes. Three of the six patients had accompanying duodenal stenosis.

CONCLUSIONS

Duodenal wall cysts occur mainly in the muscularis propria of the duodenum associated with both myofibroblasts and smooth muscle proliferation, and may result in duodenal stenosis. These cysts may be derived from a ductal component of ectopic pancreatic tissue.