Satoshi Iwasa

Peroxiredoxin I expression in oral cancer: a potential new tumor marker

This study investigates the applicability of the novel antioxidant protein, peroxiredoxin (Prx) I as a marker for tumor status in oral squamous cell carcinoma (SCC). Samples from 53 patients with SCC in the oral cavity were examined by immunohistochemistry. Correlations between the expression level of Prx I and proliferating cell nuclear antigen (PCNA), the clinical features of tumors, and their histopathological classifications were statistically analyzed. Cases exhibiting low Prx I expression level included significantly more with larger tumor mass cases (T-category, P=0.004), positive lymph node metastasis (N-category, P=0.015), advanced stage (P=0.002), and poorly differentiated cells (P=0.020). There was no significant difference between Prx I expression and the other indices.

Increased immunoreactivity of endothelin-1 and endothelin B receptor in human atherosclerotic lesions. A possible role in atherogenesis.

This study was designed to analyze the distribution and localization of endothelin-1 (ET-1) and ET receptors (ET(A) and ET(B)) at different stages of human atherosclerotic lesions by immunohistochemistry. Compared with ET(A) receptors, there was increased immunoreactivity of ET-1 and ET(B) receptor in both unfoamy and foamy macrophages and T lymphocytes in fatty streak and fibrous plaque lesions. In addition, medial SMCs located just beneath the foam cell lesions revealed a higher intensity of ET(B) receptor immunoreactivity than those located beneath the normal-looking intima without foam cells. In fibrous plaques, intimal SMCs near foam cells showed an increased density of ET receptors with predominant ET(B) immunoreactivity. In the areas where SMCs showed ET(B) receptor, ET-1 immunoreactivity was also enhanced. These results suggest that accumulation of foamy macrophages and T lymphocytes may modulate the switching of ET receptor subtypes from ET(A) to ET(B) in vascular SMCs. and that the enhanced ET system mediated by ET(B) receptors may play active roles in the progression of atherosclerosis.

Heme oxygenase-1 expression in oral squamous cell carcinoma as involved in lymph node metastasis

Thirty-eight oral squamous cell carcinomas (SCCs) were semi-quantitatively analyzed by immunohistochemical staining, and the relation between heme oxygenase-1 (HO-1) expression and the clinical status were correlated. High immunostaining of HO-1 was detected in lymph node metastasis negative groups (P = 0.0018) and in well-differentiated SCCs (P = 0.0016). There were no significant correlations between heme oxygenase-1 expression and other factors, such as size of the tumor, staging, age and sex. These findings further support the proposition that high heme oxygenase-1 expression in oral SCCs can be useful in identifying patients at low risk of lymph node metastasis.

Role of Endothelin-1 in Atherosclerosisa

Abstract: Increased evidence has shown that endothelin‐1 (ET‐1) derived from the arterial cells is involved in the development of atherosclerosis. ET‐1 and ET receptors are upregulated in both human and experimental animal atherosclerotic lesions. Plasma ET‐1 levels are significantly elevated in hypercholestolemic subjects and cholesterol‐fed animals. We hypothesized that plasma lipoproteins such as LDL and HDL retained in the arterial wall can affect ET‐1 production and secretion, thereby sustaining vascular functions. Using a two‐chamber culture system, we have demonstrated that endothelial cells (ECs) show a polar secretion of ET‐1; the majority of ET‐1 are secreted toward the basal side of the vessels. Furthermore, we found that LDL enhances whereas HDL inhibits the ET‐1 secretion from ECs in a polarized pattern. In order to demonstrate ET receptor distribution in the lesion, we recently studied both human and apoE‐KO mice. Our study showed that there is an increased expression of ETB receptors in foamy macrophages in the lesions. More importantly, medial smooth muscle cells (SMCs) beneath the foam cell lesions exhibited a higher intensity of ETB receptor immunoreactivity than those located in foam cell‐free areas. In such an area, ET‐1 immunoreactivity is also increased. These results suggest that accumulation of foamy macrophages may modulate the shift of ET receptor subtypes from ETA to ETB in SMCs and an enhanced ET system mediated by ETB receptors may play a pivotal role in the progression of atherosclerosis. This notion has been further supported by a recent finding that administration of ET receptor antagonists resulted in a significant reduction of atherosclerosis in apoE‐KO mice.

Corresponding distributions of increased endothelin‐B receptor expression and increased endothelin‐1 expression in the aorta of apolipoprotein E‐deficient mice with advanced atherosclerosis

Endothelin (ET)‐1 causes proliferation of vascular smooth muscle cells (VSMC). Although it has been reported that stimulation of ETB receptors as well as ETA receptors promote proliferation of VSMC, the precise distribution of each receptor subtype in atherosclerotic vessels is unknown. Previous studies demonstrated that apolipoprotein E (apoE)‐deficient mice have hypercholesterolaemia and develop severe atherosclerosis. To investigate the pathophysiological roles of vascular ET system in atherosclerosis, we examined preproET‐1 messenger ribonucleic acid expression in the aorta of apoE‐deficient mice, and performed immunohistochemical staining for ET‐1 and each ET receptor subtype (ETA and ETB receptors) in the atherosclerotic lesions of these mice. The level of preproET‐1 mRNA in the aorta was significantly higher in the apoE‐deficient mice than in the control mice. Strong ET‐1 staining was observed in the macrophage‐foam cells, intimal and medial VSMC in the atherosclerotic lesions of the apoE‐deficient mice. In addition, in the atherosclerotic lesions, strong ETB receptor staining was observed in the macrophage‐foam cells, intimal and medial VSMC, which distribution corresponded closely to that of ET‐1. ETA receptor staining was observed in the medial VSMC of both groups, but not in the macrophage‐foam cells of the apoE‐deficient mice. ETA receptor staining in the medial VSMC was stronger in the apoE‐deficient mice than in the control mice. These results suggest that the vascular ET system, including ET‐1 and ET receptors, is activated in the atherosclerotic lesions of apoE‐deficient mice. Since the distribution of strong ETB receptor staining corresponded closely to that of ET‐1, it is suggested that the ET system, mediated by ETB receptors, has an important role in the pathophysiology of the atherosclerotic lesions of apoE‐deficient mice.

Blockade of Endothelin Receptors Reduces Diet-Induced Hypercholesterolemia and Atherosclerosis in Apolipoprotein E-Deficient Mice

Objective: Endothelin (ET)-1 has proatherogenic properties, since ET receptor antagonists reduce atherosclerotic lesions in animals. However, we recently demonstrated that ET-1 and ETB receptors are increased in atherosclerotic lesions. To further examine the effects of ETB receptor antagonism on atherogenesis, we investigated the chronic effects of the nonselective ETA/ETB receptor antagonist SB209670 on the development of atherosclerosis in apolipoprotein E (ApoE)-deficient mice. Methods: Ninety-four male mice (10 weeks of age) were randomly divided into four groups: mice fed a Western-type diet or a chow diet with SB209670 treatment (10 mg/kg/day) or placebo for 12 weeks. Results: In mice fed the Western-type diet, but not in mice fed the chow diet, treatment with SB209670 significantly attenuated the increase in plasma total cholesterol, predominantly in the very-low-density lipoprotein and intermediate-density lipoprotein fractions, without altering the plasma triglyceride level. Furthermore, treatment with SB209670 significantly reduced the extent of aortic atherosclerosis, by 53% in mice fed the Western-type diet and by 38% in mice fed the chow diet. Histological analysis revealed that SB209670 prevented the formation of atheromatous plaque lesions by inhibiting the fibroproliferative process. Conclusion: We found that chronic administration of SB209670 reduced diet-induced hypercholesterolemia and atherosclerosis in ApoE-deficient mice. Thus, nonselective ET receptor antagonists may have a therapeutic potential in the treatment of human atherosclerotic disease.

Ultrasonographic assessment for response to radiochemotherapy of metastatic cervical lymph nodes in head and neck cancer: usefulness of grey-scale and color doppler sonography.

To predict the response of lymph node metastasis to preoperative radiochemotherapy sonographically, the correlation between ultrasonographs and histologic features was retrospectively examined in 43 metastatic cervical lymph nodes from 24 patients with squamous cell carcinoma in the oral and maxillofacial region. Ultrasonographs were compared among poor-, good-, and complete-response lymph nodes. Before radiochemotherapy, hypoechoic internal echo and intranodal blood perfusion demonstrated many complete-response nodes; in contrast, most poor-response nodes showed peripheral blood perfusion and an avascular pattern, but did not have specific internal echo intensity. Complete-response nodes showed a significant reduction in their maximum and minimum diameters after radiochemotherapy. These results indicate that ultrasonography is useful for predicting the response of cervical lymph node metastasis to radiochemotherapy.

Bone marrow chimerism prevents atherosclerosis in arterial walls of mice deficient in apolipoprotein E

OBJECTIVE apolipoprotein E (apoE) is a key regulator in cholesterol-rich lipoprotein metabolism. Inherited deficiency of this protein results in type III hyperlipoproteinemia in humans. ApoE, especially that derived from macrophages, can efficiently protect against development of atherosclerotic lesion. To use stem cell gene therapy or mini-transplant in treating abnormal lipid metabolism and preventing atherosclerosis, a minimal level of bone marrow chimerism must be determined. METHODS lethally irradiated apoE deficient mice (12-16 weeks of age) fed on normal chow were transplanted with normal bone marrow cells (C57BL/6.Ly5.1) mixed with those of apoE deficient mice (C57BL/6.Ly5.2) at various ratios. Plasma cholesterol levels were determined every 3 weeks for up to 42 weeks. Areas of atherosclerotic lesion in the aortas were quantified 6 months post-transplant. Plasma apoE was measured by Western blot analysis. RESULTS bone marrow transplantation (BMT) in apoE (-/-) mice resulted in a detectable level of plasma apoE as determined by Western blot analysis. The plasma cholesterol levels in mice with > or = 60% chimerism were normalized by 6 weeks post-transplant. Mice with < or = 40% chimerism showed significant reductions, but not normalization, in the plasma cholesterol levels even at 42 weeks posttransplant. However, atherosclerotic areas observed in 10%-chimeric mice were significantly smaller than those in control mice (P<0.01). Immunohistochemical studies in 10%-chimeric mice revealed foam cells derived from donor marrow (apoE (+/+)) and expressed immunoreactive apoE in the atherosclerotic lesion. The positive signals by Western blot analysis were represented in the plasma of up to 8% of the chimeric mice. CONCLUSION chimerism of 10%, the minimum level analyzed, was sufficient to reduce the severity of atherosclerosis, although the plasma cholesterol levels were not completely normalized. The results indicate that stem cell gene therapy and mini-transplant may provide possible therapeutic approaches to treat patients with abnormal lipid metabolism and atherosclerosis.

c-Abl expression in oral squamous cell carcinomas

c-Abl is proto-oncogene product. c-Abl has roles in signal transduction, cell cycle regulation, and inhibition of apoptosis. There are many reports about c-Abl function in hematopoietic cells, but few are concerned with solid tumors. In the present study, biopsy specimens from 44 patients with oral squamous cell carcinomas were subjected to immunohistochemistry, and the expression levels of c-Abl were correlated with clinicopathological features. Statistical analyses revealed that c-Abl expression was significantly associated with T-category (p = 0.011), sex (p = 0.014), and differentiation (p = 0.007), but no significant difference was observed with N-category, age, primary tumor region, or the other histological gradings. The low c-Abl expression group included more T4, male, and poorly differentiated cases. There was a trend towards longer tendency survival in the high expression group, but the difference was not significant. We conclude that c-Abl is a good candidate for a tumor-expansion marker.

Three autopsied cases of cystic fibrosis in Japan

The incidence of cystic fibrosis (CF) is very rare in Japanese, while it is frequent in Caucasians. Here we report on three Japanese cases of CF. One of the patients had consanguineous parents. All three patients initially developed meconium ileus, and hepatobiliary and pancreatic changes became more severe as age increased. The ΔF508 mutation, the most frequent mutation associated with CF in Caucasians, was not found in these patients. To evaluate the relationship between the severity of hepatic lesions and a history of meconium ileus, we examined hepatic lesions in the present three cases, and we reviewed 22 Japanese autopsied cases of CF in the literature. No correlation was found between the incidence of biliary cirrhosis and a history of meconium ileus, because the cases with meconium ileus showed a high mortality during the neonatal period, before biliary cirrhosis developed. The high incidence of meconium ileus in Japanese CF patients may relate to a clinically severe phenotype and reflect a different genetic background between Caucasians and Japanese.