Serum osteoprotegerin levels and long-term prognosis in subjects with stable coronary artery disease

BACKGROUND

Osteoprotegerin (OPG) is a secretory glycoprotein which belongs to the tumor necrosis factor receptor family. OPG immunoreactivity was demonstrated in normal blood vessels and in early atherosclerotic lesions. In a previous study, we showed that high serum OPG levels are associated with progression of coronary artery disease (CAD).

OBJECTIVES

The present study was designed to assess the association between serum OPG level and long-term prognosis in patients with stable coronary artery disease.

METHODS

We performed a prospective, observational cohort study in 225 subjects to examine whether serum OPG levels can predict cardiovascular mortality. The median OPG levels were 1.02 ng mL(-1) at baseline.

RESULTS

During the follow-up (61 + or - 25 months), 27 deaths occurred including 13 cardiovascular deaths. When the subjects were divided into three groups according to serum OPG level, the group with high serum OPG showed a higher risk for cardiovascular mortality. A Multivariate Cox proportional hazards model indicated that the higher risk of cardiovascular death in the high OPG level group remained significant (hazards ratio of 7.44, 95%CI 0.92-60.30, highest vs. lowest OPG tertile). In contrast, serum OPG levels were not associated with non-cardiovascular mortality.

CONCLUSIONS

Our data show that serum OPG levels are an independent predictor of cardiovascular mortality in patients with stable coronary artery disease.

[Advanced thymic carcinoma effectively treated by surgical resection and postoperative radiation therapy: report of a case]

Thymic carcinomas are rare neoplasms, and standard treatment has not yet been established. We reported a case of advanced thymic carcinoma effectively treated by surgical resection and postoperative radiation therapy. A 71-year-old man was pointed out an abnormal shadow on chest X-ray. Chest computed tomography (CT) scan demonstrated an anterior mediastinal tumor. The tumor was diagnosed as carcinoma by CT-guided tumor biopsy and was extirpated completely with combined partial resection of the left lung. Microscopically, the tumor was diagnosed as thymic carcinoma with direct invasion to the left lung. Following postoperative radiation therapy, the patient is doing well without apparent recurrence 5 years after surgery.

The direct PAK1 inhibitor, TAT-PAK18, blocks preferentially the growth of human ovarian cancer cell lines in which PAK1 is abnormally activated by autophosphorylation at Thr 423

So far no effective therapeutic has been developed for the FDA-approved treatment of ovarian cancer patients. Recently we provided the first evidence indicating that an old antibiotic (antiparasitic drug) called Ivermectin suppresses the growth of a variety of human ovarian cancer cell lines in vitro by inactivating the oncogenic kinase PAK1 somehow (Hashimoto H, et al. Drug Discov Ther. 2009;3:243-246). This kinase is now known to be essential for the growth of more than 70% of all human cancers including breast, prostate, pancreatic, colon, gastric, lung, cervical, thyroid cancers as well as hepatoma, glioma, melanoma, MM (multiple myeloma) and NF (neurofibromatosis) tumors. In this study, using the cell-permeable PAK1-inactivating peptide TAT-PAK18 which blocks the essential PAK1-PIX interaction, we examined the relationship between the sensitivity of ovarian cancer cell lines to this anti-PAK1 peptide and the protein expression/autophosphorylation levels of PAK1 in these cell lines, and found that the more PAK1 is abnormally activated (autophosporylated at Thr 423), the more their growth is sensitive to this peptide, regardless of their PAK1 expression levels. This observation provides the first direct evidence that ovarian cancers also belong to the PAK1-dependent cancers which represent more than 70% of all human cancers, suggesting that anti-PAK1 drugs would be effective therapeutics for ovarian cancers.

Ivermectin inactivates the kinase PAK1 and blocks the PAK1-dependent growth of human ovarian cancer and NF2 tumor cell lines

Ivermectin is an old anti-parasitic antibiotic which selectively kills nematodes at a very low dose (0.2 mg/kg) by inhibiting their GABA (gamma-aminobutyric acid) receptor, but not mammalian counterpart. Interestingly, several years ago it was reported by a Russian group that Ivermectin can suppress almost completely the growth of human melanoma and a few other cancer xenografts in mice at the much higher doses (3-5 mg/kg) without any adverse effect on mice. However, its anti-cancer mechanism still remained to be clarified at the molecular levels, that would determine the specific type of cancers susceptible to this drug. The first hint towards its anti-PAK1 potential was a recent finding that Ivermectin at its sublethal doses dramatically reduces the litter size (number of eggs laid) of the tiny nematode C. elegans. Interestingly, either a PAK1-deficiency (gene knock-out) or treatment with natural anti-PAK1 products such as CAPE (caffeic acid phenethyl ester) and ARC (artepillin C), the major anti-cancer ingredients in propolis, also causes the exactly same effect on this nematode, suggesting the possibility that the kinase PAK1 might be a new target of Ivermectin. This kinase is required for the growth of more than 70% of human cancers such as pancreatic, colon, breast and prostate cancers and NF (neurofibromatosis) tumors. Here we demonstrate for the first time that Ivermectin blocks the oncogenic kinase PAK1 in human ovarian cancer and NF2-deficient Schwannoma cell lines to suppress their PAK1-dependent growth in cell culture, with the IC50 between 5-20 μM depending on cell lines.

Experimental ischaemia-reperfusion injury induces vascular endothelial growth factor expression in the rat testis

Testicular torsion causes ischaemia-reperfusion (I-R) injury of testis and might lead to male infertility. Its injury initiates a pathophysiological cascade, including an activation of inflammatory cytokines and generation of nitric oxide and other reactive oxygen species. Vascular endothelial growth factor (VEGF) mediates angiogenesis and promotes endothelial cell survival. The aim of our study was to investigate the time course expression of VEGF, VEGF-receptor (R)1, VEGF-R2, nitric oxide synthases (NOS) in experimental I-R injury of rat testis. In torsion side testis, the expression of VEGF protein and mRNA significantly increased in a time-dependent manner (P < 0.001 and P < 0.001, respectively). Although the expression of VEGF-R1 mRNA was increased in a similar way (P < 0.001), VEGF-R2 mRNA expression was not detected. In immunohistochemistry, the increase in VEGF protein staining was observed in testicular vascular endothelial cells and germ cells at 24 h after reperfusion. Significant activation of inducible NOS and endothelial NOS was investigated at 12 and 24 h after reperfusion (P < 0.01 and P < 0.001, respectively). This is the first report to show the time course expression of VEGF in experimental I-R rat testis.

Characterization of autoreactive T-cell clones to myeloperoxidase in patients with microscopic polyangiitis and healthy individuals

OBJECTIVE

To characterize autoreactive T cells against myeloperoxidase (MPO) by generating antigen-specific T-cell clones from patients with microscopic polyangiitis (MPA) and healthy individuals.

METHODS

Peripheral blood T cells from five patients with MPA and MPO-anti-neutrophil cytoplasmic antibodies (ANCAs) and from three healthy donors were used to establish MPO-specific T-cell clones by repeated stimulation with recombinant MPO fragments, followed by limiting dilution. The MPO-specific T-cell clones were subjected to analyses for CD4/CD8 phenotype, human leukocyte antigen (HLA) class II restriction, T-cell receptor (TCR) Beta-chain gene usage, complementarity-determining region 3 (CDR3) amino acid sequences, and cytokine expression profiles.

RESULTS

We successfully generated seven MPO-specific T-cell clones, five from the patients and two from healthy donors. Two clones recognized the light chain of MPO and five recognized the heavy chain. All the clones were HLA-DR-restricted CD4(+)CD8(-) helper T cells. The T-cell clones shared TCR Beta CDR3 amino acid motifs, depending on their MPO epitope: AGXiXiN was used by clones recognizing the light chain and TGXiS or QGXiE by those recognizing the heavy chain, whether the cells were derived from MPA patients or healthy subjects. However, the cytokine expression profiles of the patients' clones were skewed towards the Th1 phenotype, whereas the healthy individuals' clones remained Th0.

CONCLUSIONS

We have characterized MPO-reactive T cells in detail. This information may be useful for elucidating the mechanism of ANCA production and for developing selective therapeutic strategies for MPO-ANCA-associated vasculitis.

Cocktail-substrate assay system for mechanism-based inhibition of CYP2C9, CYP2D6, and CYP3A using human liver microsomes at an early stage of drug development

We established a mechanism-based inhibition cocktail-substrate assay system using human liver microsomes and drug-probe substrates that enabled simultaneous estimation of the inactivation of main cytochrome P450 (CYP) enzymes, CYP2C9, CYP2D6, and CYP3A, in drug metabolism. The inactivation kinetic parameters of typical mechanism-based inhibitors, tienilic acid, paroxetine, and erythromycin, for each enzyme in the cocktail-substrate assay were almost in agreement with the values obtained in the single-substrate assay. Using this system, we confirmed that multiple CYP inactivation caused by mechanism-based inhibitors such as isoniazid and amiodarone could be detected simultaneously. Mechanism-based inhibition potency can be estimated by the determination of the observed inactivation rate constants (k(obs)) at a single concentration of test compounds because the k(obs) of eleven CYP3A inactivators at 10 microM in the assay system nearly corresponded to k(inact)/K(I) values, an indicator of a compound's propensity to alter the activity of a CYP in vivo (R(2) = 0.97). Therefore, this cocktail-substrate assay is considered to be a powerful tool for evaluating mechanism-based inhibition at an early stage of drug development.

Possible importance of immunoglobulin E in foetal loss by mothers with anti‐SSA antibody

OBJECTIVE

The incidence of foetal loss and/or adverse foetal outcomes, including congenital heart block (CHB), has been investigated in mothers with anti-SSA antibody detected by immunodiffusion or counter-immunoelectrophoresis methods. We investigated the relationship between several serum parameters (such as autoantibodies and immunoglobulins) and foetal loss in patients with anti-SSA antibody, measured by enzyme-linked immunosorbent assay (ELISA).

MATERIAL AND METHODS

Thirty-seven women who showed positivity for anti-SSA antibody and had a history of pregnancy were included in this study. Immunoglobulins and several autoantibodies were assayed by routine laboratory methods at our hospital.

RESULTS

Our data indicated that immunoglobulin E (IgE) levels were significantly higher in the anti-SSA antibody positive women with foetal loss than in those without, and that a strong positive correlation between IgE and anti-SSA antibody levels was observed in the former group, but not in the latter.

CONCLUSION

The serum IgE level seems to be an important factor in the occurrence of foetal loss in mothers with anti-SSA antibody detected by ELISA.

Response of arginine vasopressin-enhanced green fluorescent protein fusion gene in the hypothalamus of adjuvant-induced arthritic rats

Arginine vasopressin (AVP) and corticotrophin-releasing hormone (CRH) in the parvocellular neurosecretory cells of the paraventricular nucleus (PVN) play a major role in activating the hypothalamic-pituitary-adrenal axis, which is the main neuroendocrine response against the many kinds of stress. We examined the effects of chronic inflammatory/nociceptive stress on the expression of the AVP-enhanced green fluorescent protein (eGFP) fusion gene in the hypothalamus, using the adjuvant arthritis (AA) model. To induce AA, the AVP-eGFP rats were intracutaneously injected heat-killed Mycobacterium butyricum (1 mg/rat) in paraffin liquid at the base of their tails. We measured AVP, oxytocin and corticosterone levels in plasma and changes in eGFP and CRH mRNA in the hypothalamus during the time course of AA development. Then, we examined eGFP fluorescence in the PVN, the supraoptic nucleus (SON), median eminence (ME) and posterior pituitary gland (PP) when AA was established. The plasma concentrations of AVP, oxytocin and corticosterone were significantly increased on days 15 and 22 in AA rats, without affecting the plasma osmolality and sodium. Although CRH mRNA levels in the PVN were significantly decreased, eGFP mRNA levels in the PVN and the SON were significantly increased on days 15 and 22 in AA rats. The eGFP fluorescence in the SON, the PVN, internal and external layers of the ME and PP was apparently increased in AA compared to control rats. These results suggest that the increases in the concentrations of ACTH and corticosterone in AA rats are induced by hypothalamic AVP, based on data from AVP-eGFP transgenic rats.

A comparative study of the diagnostic accuracy of ELISA systems for the detection of anti-neutrophil cytoplasm antibodies available in Japan and Europe

OBJECTIVES

Primary systemic vasculitis associated with anti-neutrophil cytoplasm antibodies (ANCA) differs in its frequency and clinical expression between Japan and Europe. We sought to ascertain whether such differences arise from the performance of enzyme-linked immunosorbent assays (ELISAs) for ANCA.

METHODS

Plasma samples from 64 consecutive Japanese patients with a clinical and histological diagnosis of primary systemic vasculitis including microscopic polyangiitis (MPA; n=52), Churg-Strauss syndrome (CSS; n=1), and Wegener's granulomatosis (WG; n=11), or those from disease controls with non-vasculitic glomerulonephritis (n=54) and healthy controls (n=55) were tested for the presence of myeloperoxidase (MPO) by ELISAs available in Japan (Nipro and MBL) and compared with those in Europe (Wieslab). The sensitivity and specificity were calculated for each ELISA, and its diagnostic performance was assessed by receiver operating characteristic curve analysis.

RESULTS

The sensitivity and specificity of either MPO-ANCA assays for a diagnosis of MPA were 90.4% and 98.2% (Nipro), 88.2% and 96.3% (MBL), and 86.5% and 99.1% (Wieslab). The overall diagnostic performance, assessed as the area under curve of the MPO-ANCA ELISAs for MPA were 0.946+/-0.022 (Nipro), 0.970+/-0.017 (MBL), and 0.971+/-0.017 (Wieslab), while that of PR3-ANCA ELISAs for WG were 0.986+/-0.025 (Nipro), 0.993+/-0.017 (MBL), and 0.916+/-0.059 (Wieslab).

CONCLUSIONS

The MPO-ANCA ELISAs commercially available in Japan exhibited high sensitivity and specificity for the diagnosis of ANCA-associated vasculitides and provided similar diagnostic value to those in Europe. These results facilitate further international comparison of ANCA-associated vasculitides between Japanese and European populations.