A case of hepatitis C-associated osteosclerosis that was improved with the combination therapy of peginterferon alfa-2b and ribavirin

Hepatitis C-associated osteosclerosis (HCAO) is a rare disorder characterized by a marked increase in skeletal mass in patients who are infected with hepatitis C virus (HCV). The clinical presentation is an acquired deep bone pain with increased serum alkaline phosphatase (ALP) activity. We present a case of a patient with HCAO who was treated with antiviral therapy. A 42-year-old Japanese man presented with severe, stabbing pain in his lower limbs. He was diagnosed with hepatitis C secondary to intravenous drug use 20 years earlier. Serum biochemical studies revealed markedly elevated ALP activity and osteocalcin levels. Skeletal radiographs showed diffuse bony sclerosis with marked cortical thickening in the long bones. The bony findings and clinical symptoms were attributed to HCAO. The HCV RNA viral load was high and the genotype was 2a. The patient was treated with peginterferon alfa-2b and ribavirin for 24 weeks. After 24 weeks of the combination therapy, the patient had a sustained virological response and clinical remission of bone pain and a decrease in the level of serum ALP. In conclusion, HCAO was improved by the combination therapy of peginterferon alfa-2b and ribavirin when the patient achieved sustained virological response. It was confirmed that HCAO was one of the extrahepatic manifestations of HCV.     

Reduced Tim-3 expression on human T-lymphotropic virus type I (HTLV-I) Tax-specific cytotoxic T lymphocytes in HTLV-I infection

T cell immunoglobulin and mucin domain-containing molecule-3 (Tim-3) and programmed cell death-1 (PD-1) are T cell exhaustion molecules. We investigated the expression of Tim-3 and PD-1 in human T-lymphotropic virus type I (HTLV-I) infection. Tim-3 expression, but not PD-1 expression, was reduced on CD4(+) and CD8(+) T cells of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients and HTLV-I carriers as compared with healthy controls. Tim-3 expression was also reduced in HTLV-I Tax-specific cytotoxic T lymphocytes (CTLs) as compared with cytomegalovirus-specific CTLs. Tim-3(+), but not PD-1(+), Tax-specific CTLs produced less interferon-γ and exhibited low cytolytic activity. However, we observed no difference in the expression of Tim-3 or cytolytic activity between Tax-specific CTLs of HAM/TSP patients or carriers. Moreover, HTLV-I-infected CD4(+) T cells showed decreased Tim-3 expression. These data suggest that Tim-3 expression is reduced in HTLV-I infection and that a high number of Tim-3(-) HTLV-I-specific CTLs preserves their cytolytic activity, thereby controlling viral replication.     

Nrf2-mediated induction of p62 controls Toll-like receptor-4-driven aggresome-like induced structure formation and autophagic degradation

Toll-like receptors (TLRs) play a crucial role in several innate immune responses by regulating autophagy, but little is known about how TLR signaling controls autophagy. Here we demonstrate that p62/SQSTM1 is required for TLR4-mediated autophagy, which we show as selective autophagy of aggresome-like induced structures (ALIS). Treatment with LPS or Escherichia coli induced LC3(+) dot-like structures, and their assembly, but not lysosomal degradation, occurred independently of classic autophagic machinery. Microscopic and ultrastructural analyses showed that p62 is a component of the induced LC3(+) dots and these TLR4-induced p62(+) structures resemble ALIS. The levels of p62 mRNA and protein were increased in TLR4-activated cells and knockdown of p62 suppressed the ALIS formation and LC3-II conversion. The accumulation of p62 and ALIS required activation of Nrf2 by reactive oxygen species-p38 axis-dependent TLR4/MyD88 signaling, suggesting a link between innate immune and oxidative-stress responses. These findings indicate that TLR4-driven induction of p62 plays an essential role in the formation and the autophagic degradation of ALIS, which might be critical for regulating host defense.     

Oxidative stress-induced formation of a positive-feedback loop for the sustained activation of p38 MAPK leading to the loss of cell division in cardiomyocytes soon after birth

Shortly after birth, mammalian cardiomyocytes irreversibly exit from the cell cycle and become terminally differentiated. The cellular mechanisms responsible for the cessation of cell division and terminal differentiation of cardiomyocytes soon after birth have intrigued developmental biologists as well as cardiovascular physicians, but the genetic cues for the irreversible exit from the cell cycle soon after birth remain largely unknown. We examined whether and if so how oxidative stress to mammalian hearts during fetal–neonatal transition produces changes in the proliferative activity and terminal differentiation of cardiomyocytes. Scavenging of reactive oxygen species (ROS) during fetal–neonatal transition, especially after birth, resulted in an increase in the proliferative activity and a decrease in the ratio of binucleated cardiomyocytes. Exposure to ROS in cultured cardiomyocytes increased the activity of p38 MAPK and the expression of connexin 43 (Cx43). Not only knockdown of Cx43 using siRNA but also the inhibition of p38 MAPK activity resulted in a significant decrease in the production of ROS in cardiomyocytes, suggesting that the signaling pathway ROS–p38 MAPK–Cx43 (especially, Cx43 at mitochondria, mtCx43) constituted a closed regulatory system with positive feedback. In addition, continuous scavenging of ROS or suppression of p38 MAPK activity for 4 days after birth resulted in a significant decrease in the expression of mtCx43 and in the number of binucleated cardiomyocytes. This study demonstrated that the ROS-induced formation of a positive-feedback loop ROS–p38 MAPK–mtCx43 for the sustained activation of p38 MAPK soon after birth possibly contributes to the loss of cell division and binucleation in mammalian cardiomyocytes.     

Peroxiredoxin I protects gastric mucosa from oxidative injury induced by H. pylori infection

Background and Aim: Helicobacter pylori (H. pylori) infection enhances the production of reactive oxygen species and peroxynitrite, thereby resulting in oxidative tissue damage. In this study, we examined the role of peroxiredoxin I (Prx I), a stress‐induced antioxidant enzyme, in protecting gastric mucosa from H. pylori‐induced gastric mucosal injury. Methods: Wild type (Prx I^+/+) and Prx I‐deficient type (Prx I^–/–) mice were maintained for 2 to 12 months with or without infection of H. pylori, Sydney strain‐1. Gastric mucosal expression of Prx I was assessed by immunoblot analysis and immunohistochemistry. The degree of gastritis was evaluated by the updated Sydney system and by mucosal levels of inflammatory cytokines (MIP‐2, IL‐1β, and TNF‐α). Oxidative DNA injury and apoptosis were analyzed by mucosal level of 8‐hydroxy‐2′‐deoxyguanosine, and the number of apoptotic cells stained with a single‐stranded DNA antibody, respectively. Results: H. pylori infection upregulated gastric mucosal Prx I expression in the Prx I^+/+ but not the Prx I^–/– mice. H. pylori infection also induced more severe gastritis and a more prominent increase in MIP level, more marked oxidative DNA injury, and apoptosis in the Prx I^–/– than the Prx I^+/+ mice. In the absence of H. pylori infection, no changes were demonstrated in gastric mucosa in either the Prx I^+/+ or the Prx I^?/? mice. Conclusion: These data suggest that H. pylori infection upregulates gastric mucosal Prx I expression, and further, that Prx I plays an important role in gastric mucosal protection against oxidative injury induced by H. pylori infection.     

AST-120 (Kremezin) initiated in early stage chronic kidney disease stunts the progression of renal dysfunction in type 2 diabetic subjects

There is little clinical evidence when AST-120 should be prescribed for subjects with early stage overt diabetic nephropathy. We therefore designed a prospective, randomized, controlled study for subjects with type 2 diabetes (serum creatinine <1.5 mg/dl and urinary protein >0.5 g/day) in November, 2001. The primary end point was defined as exceeding 2 mg/dl of serum creatinine, and the secondary end point was defined as introducing a hemodialysis. Twenty-two subjects were selected, and after excluding 6 drop-out subjects, 16 subjects (10 in the control group; 6 in the KRM group) finally entered the study. Mean follow-up periods were 37 and 34 months in the control and KRM groups, respectively. There was no difference in clinical characteristics including renal dysfunction at baseline between the two groups. There was a significant reduction in urinary indoxyl sulfate at month 12 in the KRM group than in the control group. A significant difference was observed in changes in mean levels of serum creatinine versus time between the two groups. The primary end points were counted in 7 (70%) of the control subjects, while only 1 (17%) of the KRM group, and the Kaplan–Meier analysis was statistically significant. Although 4 (40%) of the control group and 1 (17%) of the KRM group were initiated hemodialysis as the secondary end point, the difference did not reach a statistical significance. Thus, we concluded that administration of AST-120 initiated in early stage overt diabetic nephropathy stunts the progression of renal dysfunction.     

Tristetraprolin (TTP) gene polymorphisms in patients with rheumatoid arthritis and healthy individuals

Tristetraprolin (TTP) is an intracellular protein that modulates the production of cytokines, including TNFα, by binding to and destabilizing the mRNAs of these cytokines. Therefore, differences in TTP gene expression may affect the severity of inflammatory diseases, such as rheumatoid arthritis (RA). We searched for polymorphisms in the human TTP gene and for this purpose, we sequenced the entire TTP gene in 20 Japanese individuals (ten with RA and ten healthy volunteers) and found one single nucleotide polymorphism (SNP) in the promoter region. We analyzed this SNP (A/G) by restriction fragment length polymorphism method in 155 RA patients and 100 control subjects. While the frequency of A allele in this SNP was similar in RA patients (74.5%) and controls (76.0%), the disease duration in RA patients with genotype GG was shorter than that of patients with genotypes AA/AG and RA patients with genotype GG had a higher probability of being treated with infliximab. We studied the difference in promoter activity between the two alleles by luciferase assay and found that the promoter activity of TTP promoter region with allele A was around two-fold higher than that with allele G. We conclude that this SNP in the promoter region of the TTP gene mildly affects promoter activity, and thus, may influence the disease activity of inflammatory disorders including RA.     

Antibacterial properties of some cyclic organobismuth(III) compounds

Bismuth compounds are known for their low levels of toxicity in mammals, and various types of bismuth salts have been used to treat medical disorders. As part of our program to probe this aspect of bismuth chemistry, cyclic organobismuth compounds 1 to 8 bearing a nitrogen or sulfur atom as an additional ring member have been synthesized, and their antimicrobial activities against five standard strains of gram-negative and gram-positive bacteria were assessed. The eight-membered-ring compounds, compounds 1 to 3, exhibited MICs of less than 0.5 μg/ml against Staphylococcus aureus and were more active than the six-membered ones, compounds 5 to 8 (MICs, 4.0 to 16 μg/ml). The gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Enterococcus faecalis) were more susceptible to both types of ring compounds than the gram-negative ones (Escherichia coli and Pseudomonas aeruginosa). Treatment with polymyxin B nonapeptide increased the susceptibility of E. coli to cyclic organobismuth compounds, indicating the low permeability of the outer membrane of gram-negative bacteria to the compounds. Compound 1 also had activity against methicillin-resistant S. aureus, which had an MIC for 90% of the hospital stock strains of 1.25 μg/ml. The killing curves for S. aureus treated with compound 1 or 3 revealed a static effect at a low dose (2× the MIC). However, when S. aureus was treated with 10× the MIC of compound 1 or 3, there was an approximately 3-log reduction in the viable cell number after 48 h of treatment. Electron microscopic inspection demonstrated a considerable increase in the size of S. aureus and the proportion of cells undergoing cell division after treatment with compound 1 at 0.5× the MIC.     

Effects of intravenous magnesium in a prolonged QT interval model of polymorphic ventricular tachycardia focus on transmural ventricular repolarization

BACKGROUND: This study was performed to clarify the antiarrhythmic effects of magnesium sulfate (Mg(++)) in a prolonged QT interval canine model of polymorphic ventricular tachyarrhythmia (VTA). METHODS: In six experiments in a canine model of prolonged QT by anthopleurin-A, Mg(++) was administered in boluses of 0.2 mL/kg during repetitive episodes of self-terminating polymorphic VTA or frequent premature ventricular complexes (PVCs). The distribution of ventricular repolarization across the left ventricular(LV) wall and dispersion of transmural repolarization were analyzed before, and 30 and 120 seconds after Mg(++) administration, during ventricular pacing at 100 bpm. Transmural unipolar electrograms were recorded from multipolar needle electrodes, and local activation-recovery intervals (ARI) were measured. RESULTS: Mg(++) rapidly eliminated self-terminating polymorphic VTA and all isolated PVCs. During ventricular pacing at 100 bpm, Mg(++) caused modest shortening of ARI at all recording sites. Since the magnitude of ARI shortening was greater at mid-myocardial sites than at other ventricular sites, mean transmural ARI dispersion decreased from 80 +/- 22 to 45 +/- 18 ms within 30 seconds after Mg(++) injection. However, this effect was transient, and, at 120 seconds after Mg(++) administration, ARI had increased all sites and transmural ARI dispersion lengthened to 65 +/- 18 ms. Besides suppression of triggered premature activity, homogenization of transmural ventricular repolarization was associated with the antiarrhythmic effects of intravenous Mg(++) in this model. CONCLUSION: Since these effects were transient, a continuous intravenous infusion of Mg(++) is preferred to prevent recurrences of VTA.