Increased plasma LIGHT levels in patients with atopic dermatitis

LIGHT [the name of which is derived from 'homologous to lymphotoxins, exhibits inducible expression, competes with herpes simplex virus glycoprotein D for herpes simplex virus entry mediator (HVEM), and expressed by T lymphocytes'], is a member of the tumour necrosis factor superfamily that is involved in various inflammatory diseases. We aimed to estimate the relevance of plasma LIGHT levels as a biomarker for atopic dermatitis (AD). In order to understand the putative role of LIGHT in AD pathogenesis, we also investigate the effects of LIGHT on a monocytic cell line, human acute monocytic leukaemia cell line (THP-1). We examined plasma LIGHT levels, total serum IgE, serum value of CCL17 and peripheral blood eosinophil counts in patients with AD and healthy subjects. The effects of LIGHT on activation and apoptosis in THP-1 cells were also investigated. The plasma concentrations of LIGHT in AD patients were significantly higher than those in healthy individuals and the concentrations decreased as the symptoms were improved by treatment. The LIGHT plasma concentrations correlated with IgE levels and the Severity Scoring of AD (SCORAD) index. In addition, LIGHT stimulation increased expression of CD86 and induced production of interleukin-1β in THP-1 cells. Apoptosis was inhibited, the Bcl-2 level increased and the caspase-3 level decreased in THP-1 cells stimulated with LIGHT, compared to unstimulated control cells. These results suggest that plasma LIGHT levels may be one of the promising biomarkers for AD.

Lifestyle changes through the use of delivered meals and dietary counseling in a single-blind study. The STYLIST study

BACKGROUND

Dietary habits are associated with obesity, and both are important contributing factors to lifestyle-related diseases. The STYLIST study examined the effects of dietary counseling by registered dietitians and the delivery of proper calorie-controlled meals (UMIN Registration No: 000006582).

METHODS AND RESULTS

Two-hundred adult patients with hypertension and/or diabetes mellitus were randomly divided into 2 groups with/without dietary counseling and consumed an ordinary diet for 4 weeks. Each group was then subdivided into 2 groups with/without dietary counseling and received calorie-controlled lunch and dinner boxes for the next 4 weeks. The calories in the delivered meals were based on the subject's ideal body weight (BW) and physical activity level. BW, waist circumference, blood pressure, and laboratory data, including glycoalbumin, were measured at 0, 4, and 8 weeks. BW and the other parameters were significantly reduced during the study period in patients who received diet counseling in the ordinary diet period and/or delivered meal period but not in patients without dietary counseling, as assessed by linear mixed models for longitudinal data.

CONCLUSIONS

The combination of dietary counseling by dietitians and delivery of calorie-controlled meals was effective in reducing BW, as well as blood pressure and glycoalbumin, in patients with hypertension and/or diabetes mellitus.

IRS-2 deficiency in macrophages promotes their accumulation in the vascular wall

The aim of this study was to investigate the role of insulin receptor substrate-2 (IRS-2) mediated signal in macrophages on the accumulation of macrophages in the vascular wall. Mice transplanted with IRS-2(-/-) bone marrow, a model of myeloid cell restricted defect of IRS-2, showed accumulation of monocyte chemoattractant protein-1-expressing macrophages in the vascular wall. Experiments using cultured peritoneal macrophages showed that IRS-2-mediated signal pathway stimulated by physiological concentrations of insulin, not by IL-4, contributed to the suppression of monocyte chemoattractant protein-1 expression induced by lipopolysaccharide. Our data indicated that IRS-2 deficiency in macrophages enhanced their accumulation in the vascular wall accompanied by increased expression of proinflammatory mediators in macrophages. These results suggest a role for insulin resistance in macrophages in early atherosclerogenesis.

Transcriptional regulation of S phase kinase-associated protein 2 by NR4A orphan nuclear receptor NOR1 in vascular smooth muscle cells

Members of the NR4A subgroup of the nuclear hormone receptor superfamily have emerged as key transcriptional regulators of proliferation and inflammation. NOR1 constitutes a ligand-independent transcription factor of this subgroup and induces cell proliferation; however, the transcriptional mechanisms underlying this mitogenic role remain to be defined. Here, we demonstrate that the F-box protein SKP2 (S phase kinase-associated protein 2), the substrate-specific receptor of the ubiquitin ligase responsible for the degradation of p27(KIP1) through the proteasome pathway, constitutes a direct transcriptional target for NOR1. Mitogen-induced Skp2 expression is silenced in vascular smooth muscle cells (VSMC) isolated from Nor1-deficient mice or transfected with Nor1 siRNA. Conversely, adenovirus-mediated overexpression of NOR1 induces Skp2 expression in VSMC and decreases protein abundance of its target p27. Transient transfection experiments establish that NOR1 transactivates the Skp2 promoter through a nerve growth factor-induced clone B response element (NBRE). Electrophoretic mobility shift and chromatin immunoprecipitation assays further revealed that NOR1 is recruited to this NBRE site in the Skp2 promoter in response to mitogenic stimulation. In vivo Skp2 expression is increased during the proliferative response underlying neointima formation, and this transcriptional induction depends on the expression of NOR1. Finally, we demonstrate that overexpression of Skp2 rescues the proliferative arrest of Nor1-deficient VSMC. Collectively, these results characterize Skp2 as a novel NOR1-regulated target gene and detail a previously unrecognized transcriptional cascade regulating mitogen-induced VSMC proliferation.

Deficiency of the NR4A orphan nuclear receptor NOR1 decreases monocyte adhesion and atherosclerosis

RATIONALE

The orphan nuclear receptor NOR1 is a member of the evolutionary highly conserved and ligand-independent NR4A subfamily of the nuclear hormone receptor superfamily. Members of this subfamily have been characterized as early response genes regulating essential biological processes including inflammation and proliferation; however, the role of NOR1 in atherosclerosis remains unknown.

OBJECTIVE

The goal of the present study was to determine the causal contribution of NOR1 to atherosclerosis development and to identify the mechanism by which this nuclear receptor participates in the disease process.

METHODS AND RESULTS

In the present study, we demonstrate expression of NOR1 in endothelial cells of human atherosclerotic lesions. In response to inflammatory stimuli, NOR1 expression is rapidly induced in endothelial cells through a nuclear factor kappaB-dependent transactivation of the NOR1 promoter. Overexpression of NOR1 in human endothelial cells increased the expression of vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule-1, whereas NOR1 deficiency altered adhesion molecule expression in response to inflammatory stimuli. Transient transfection experiments and chromatin immunoprecipitation assays revealed that NOR1 induces VCAM-1 promoter activity by binding to a canonical response element for NR4A receptors in the VCAM-1 promoter. Further functional studies confirmed that NOR1 mediates monocyte adhesion by inducing VCAM-1 and intercellular adhesion molecule-1 expression in endothelial cells. Finally, we demonstrate that NOR1 deficiency reduces hypercholesterolemia-induced atherosclerosis formation in apoE(-/-) mice by decreasing the macrophage content of the lesion.

CONCLUSIONS

In concert, these studies identify a novel pathway underlying monocyte adhesion and establish that NOR1 serves a previously unrecognized atherogenic role in mice by positively regulating monocyte recruitment to the vascular wall.

Impact of insulin resistance on enhanced monocyte adhesion to endothelial cells and atherosclerogenesis independent of LDL cholesterol level

Epidemiological studies suggest that insulin resistance is an independent risk factor for cardiovascular disease. However, there is little information on the role of insulin resistance in atherosclerogenesis independent of LDL cholesterol level. The aim of this study was to investigate the impact of systemic insulin resistance on monocyte adhesion to endothelial cells and atherosclerotic lesions independent of LDL cholesterol level. KKAy mice are obese mice with spontaneous diabetes and insulin resistance, and normal levels of LDL cholesterol. In parallel with systemic insulin resistance, decreased insulin signal, and the increased expression of monocyte chemoattractant protein-1 (MCP-1) were noted in macrophages isolated from KKAy mice. These mice showed enhanced monocyte adhesion to the endothelial cells of the thoracic artery. Furthermore, these mice showed expanded atherosclerotic lesions when fed high cholesterol diet. Our data indicate that insulin resistance promotes the atherosclerogenesis independent of LDL cholesterol level. Decreased insulin signaling in macrophages associated with systemic insulin resistance could be involved, at least in part, in this pathological process.

Inhibition of monocyte adhesion to endothelial cells and attenuation of atherosclerotic lesion by a glucagon-like peptide-1 receptor agonist, exendin-4

OBJECTIVE

Exogenous administration of glucagon-like peptide-1 (GLP-1) or GLP-1 receptor agonists such as an exendin-4 has direct beneficial effects on the cardiovascular system. However, their effects on atherosclerogenesis have not been elucidated. The aim of this study was to investigate the effects of GLP-1 on accumulation of monocytes/macrophages on the vascular wall, one of the earliest steps in atherosclerogenesis.

RESEARCH DESIGN AND METHODS

After continuous infusion of low (300 pmol . kg(-1) . day(-1)) or high (24 nmol . kg(-1) . day(-1)) dose of exendin-4 in C57BL/6 or apolipoprotein E-deficient mice (apoE(-/-)), we evaluated monocyte adhesion to the endothelia of thoracic aorta and arteriosclerotic lesions around the aortic valve. The effects of exendin-4 were investigated in mouse macrophages and human monocytes.

RESULTS

Treatment with exendin-4 significantly inhibited monocytic adhesion in the aortas of C57BL/6 mice without affecting metabolic parameters. In apoE(-/-) mice, the same treatment reduced monocyte adhesion to the endothelium and suppressed atherosclerogenesis. In vitro treatment of mouse macrophages with exendin-4 suppressed lipopolysaccharide-induced mRNA expression of tumor necrosis factor-alpha and monocyte chemoattractant protein-1, and suppressed nuclear translocation of p65, a component of nuclear factor-kappaB. This effect was reversed by either MDL-12330A, a cAMP inhibitor or PKI(14-22), a protein kinase A-specific inhibitor. In human monocytes, exendin-4 reduced the expression of CD11b.

CONCLUSIONS

Our data suggested that GLP-1 receptor agonists reduced monocyte/macrophage accumulation in the arterial wall by inhibiting the inflammatory response in macrophages, and that this effect may contribute to the attenuation of atherosclerotic lesion by exendin-4.

Preliminary report: mitochondrial DNA 5178 polymorphism in male elite Japanese endurance runners

Elite athletic endurance ability involves multiple genetic and environmental factors, with little known about the specific genotypes involved. As a first step to finding genetic markers of endurance performance, we recruited 66 male endurance runners and 110 control athletes. We investigated the distribution of m.5178CA polymorphisms in male endurance runners. Although the m.5178A genotype has been reportedly associated with longevity, endurance runners in this study showed a significantly higher frequency (71.2%) of the m.5178C genotype than control subjects (52.7%). The-m.5178C genotype may be favorable for performance in elite endurance runners.

[ARB as a drug for diabetic microangiopathy]

Diabetes is one of the most important risk factors for mortality along with hypertension. Recently, it has emerged that ARB is a suitable anti-hypertensive drug for diabetic patients, because ARB has some features to prevent the progression of atherosclerosis in diabetic patients. Here, we summarize the evidences suggesting that ARB couldprevent not only macroangiopathy but also microangiopathy in diabetic patients. We conclude that ARB might be an ideal anti-hypertensive drug for diabetic patients.

Deficiency of the NR4A neuron-derived orphan receptor-1 attenuates neointima formation after vascular injury

BACKGROUND

The neuron-derived orphan receptor-1 (NOR1) belongs to the evolutionary highly conserved and most ancient NR4A subfamily of the nuclear hormone receptor superfamily. Members of this subfamily function as early-response genes regulating key cellular processes, including proliferation, differentiation, and survival. Although NOR1 has previously been demonstrated to be required for smooth muscle cell proliferation in vitro, the role of this nuclear receptor for the proliferative response underlying neointima formation and target genes trans-activated by NOR1 remain to be defined.

METHODS AND RESULTS

Using a model of guidewire-induced arterial injury, we demonstrate decreased neointima formation in NOR1(-/-) mice compared with wild-type mice. In vitro, NOR1-deficient smooth muscle cells exhibit decreased proliferation as a result of a G(1)-->S phase arrest of the cell cycle and increased apoptosis in response to serum deprivation. NOR1 deficiency alters phosphorylation of the retinoblastoma protein by preventing mitogen-induced cyclin D1 and D2 expression. Conversely, overexpression of NOR1 induces cyclin D1 expression and the transcriptional activity of the cyclin D1 promoter in transient reporter assays. Gel shift and chromatin immunoprecipitation assays identified a putative response element for NR4A receptors in the cyclin D1 promoter, to which NOR1 is recruited in response to mitogenic stimulation. Finally, we provide evidence that these observations are applicable in vivo by demonstrating decreased cyclin D1 expression during neointima formation in NOR1-deficient mice.

CONCLUSIONS

These experiments characterize cyclin D1 as an NOR1-regulated target gene in smooth muscle cells and demonstrate that NOR1 deficiency decreases neointima formation in response to vascular injury.

The PPARalpha/p16INK4a pathway inhibits vascular smooth muscle cell proliferation by repressing cell cycle-dependent telomerase activation

Peroxisome proliferator-activated receptor (PPAR)alpha, the molecular target for fibrates used to treat dyslipidemia, exerts pleiotropic effects on vascular cells. In vascular smooth muscle cells (VSMCs), we have previously demonstrated that PPARalpha activation suppresses G(1)-->S cell cycle progression by targeting the cyclin-dependent kinase inhibitor p16(INK4a) (p16). In the present study, we demonstrate that this inhibition of VSMC proliferation by PPARalpha is mediated through a p16-dependent suppression of telomerase activity, which has been implicated in key cellular functions including proliferation. PPARalpha activation inhibited mitogen-induced telomerase activity by repressing the catalytic subunit telomerase reverse transcriptase (TERT) through negative cross-talk with an E2F-1-dependent trans-activation of the TERT promoter. This trans-repression involved the recruitment of the retinoblastoma (RB) family proteins p107 and p130 to the TERT promoter resulting in impaired E2F-1 binding, an effect that was dependent on p16. The inhibition of cell proliferation by PPARalpha activation was lost in VSMCs following TERT overexpression or knockdown, pointing to a key role of telomerase as a target for the antiproliferative effects of PPARalpha. Finally, we demonstrate that PPARalpha agonists suppress telomerase activation during the proliferative response following vascular injury, indicating that these findings are applicable in vivo. In concert, these results demonstrate that the antiproliferative effects of PPARalpha in VSMCs depend on the suppression of telomerase activity by targeting the p16/RB/E2F transcriptional cascade.

Short-term effects of dietary fat on intramyocellular lipid in sprinters and endurance runners

The effect of short-term fat loading on intramyocellular lipid (IMCL) in different types of muscle in endurance runners and sprinters has not been fully elucidated yet. The purpose of this study was to investigate the effect of dietary lipid on IMCL in soleus muscle (SOL) and tibialis anterior muscle (TA) during training period in endurance runners and sprinters. Seven male endurance runners and 7 male sprinters were selected to participate in the study. We measured TA- and SOL-IMCL levels after 3-day course of isocaloric normal- (25%), high- (60%), and low-fat (10%) diet during training period by (1)H-magnetic resonance spectroscopy in each subject. In sprinters, TA- and SOL-IMCL levels were comparable after each diet protocol. However, in endurance runners, TA-IMCL levels after normal-fat and high-fat diets were 1.7 times and 3.0 times higher than that after low-fat diet, respectively. The SOL-IMCL values after normal-fat diet and high-fat diet were 1.5 times and 1.6 times higher than that after low-fat diet, respectively. In addition, the TA-IMCL level after high-fat diet, but not SOL-IMCL, was significantly higher compared with that after normal-fat diet. Our data suggested that short-term dietary fat challenge during training period significantly altered IMCL level in endurance runners, but not in sprinters. In addition, response to fat loading on IMCL was influenced by variation of muscle type in endurance runners. These phenotypic and regional differences might be explained by differences in type of exercise training and muscle fiber composition.

Osteopontin mediates obesity-induced adipose tissue macrophage infiltration and insulin resistance in mice

Obesity is associated with a state of chronic, low-grade inflammation characterized by abnormal cytokine production and macrophage infiltration into adipose tissue, which may contribute to the development of insulin resistance. During immune responses, tissue infiltration by macrophages is dependent on the expression of osteopontin, an extracellular matrix protein and proinflammatory cytokine that promotes monocyte chemotaxis and cell motility. In the present study, we used a murine model of diet-induced obesity to examine the role of osteopontin in the accumulation of adipose tissue macrophages and the development of insulin resistance during obesity. Mice exposed to a high-fat diet exhibited increased plasma osteopontin levels, with elevated expression in macrophages recruited into adipose tissue. Obese mice lacking osteopontin displayed improved insulin sensitivity in the absence of an effect on diet-induced obesity, body composition, or energy expenditure. These mice further demonstrated decreased macrophage infiltration into adipose tissue, which may reflect both impaired macrophage motility and attenuated monocyte recruitment by stromal vascular cells. Finally, obese osteopontin-deficient mice exhibited decreased markers of inflammation, both in adipose tissue and systemically. Taken together, these results suggest that osteopontin may play a key role in linking obesity to the development of insulin resistance by promoting inflammation and the accumulation of macrophages in adipose tissue.

PPARalpha agonists suppress osteopontin expression in macrophages and decrease plasma levels in patients with type 2 diabetes

Osteopontin (OPN) is a proinflammatory cytokine implicated in the chemoattraction of monocytes and the development of atherosclerosis. Peroxisome proliferator-activated receptor (PPAR)alpha, a ligand-activated transcription factor with pleiotropic anti-inflammatory effects in macrophages, is the molecular target for fibrates, which are frequently used to treat dyslipidemia in patients with type 2 diabetes at high risk for cardiovascular disease. In the present study, we examined the regulation of OPN by PPARalpha agonists in macrophages and determined the effect of fibrate treatment on OPN plasma levels in patients with type 2 diabetes. Treatment of human macrophages with the PPARalpha ligands bezafibrate or WY14643 inhibited OPN expression. PPARalpha ligands suppressed OPN promoter activity, and an activator protein (AP)-1 consensus site conferred this repression. Overexpression of c-Fos and c-Jun reversed the inhibitory effect of PPARalpha ligands on OPN transcription, and, in chromatin immunoprecipitation assays, PPARalpha ligands inhibited c-Fos and phospho-c-Jun binding to the OPN promoter. Moreover, c-Fos and phospho-c-Jun protein expression was inhibited by PPARalpha agonists, indicating that PPARalpha ligands suppress OPN expression through negative cross talk with AP-1-dependent transactivation of the OPN promoter. This inhibitory effect of PPARalpha ligands on OPN expression was absent in PPARalpha-deficient macrophages, suggesting a receptor-mediated mechanism of OPN suppression. Finally, treatment of type 2 diabetic patients with bezafibrate significantly decreased OPN plasma levels. These results demonstrate a novel mechanism whereby PPARalpha ligands may impact macrophage inflammatory responses and decrease early proinflammatory markers for cardiovascular disease.

Eicosapentaenoic acid reduces the progression of carotid intima-media thickness in patients with type 2 diabetes

To investigate the effect of highly purified eicosapentaenoic acid (EPA) on the progression of diabetic macroangiopathy, we performed an open-label randomized prospective trial. A total of 81 Japanese type 2 diabetes were randomly assigned to the EPA (1800 mg/day) treated group or the control group. Carotid intima-media thickness (IMT) and brachial-ankle pulse wave velocity (baPWV) were evaluated before and after treatment in both groups. Sixty patients (EPA group, n=30; control group, n=30) completed this study. During the study period of 2.1+/-0.2 years, the mean IMT and max IMT of the EPA treated group showed a significant annual decrease compared with that of the control group (mean IMT, -0.029+/-0.112 mm versus 0.016+/-0.109 mm, respectively, P=0.029; max IMT, -0.084+/-0.113 mm versus -0.005+/-0.108 mm, respectively, P=0.0008). The baPWV was also improved significantly in the EPA treated group compared with the control group (-22.1+/-127.9 cm/s versus 62.3+/-223 cm/s, respectively, P=0.021). Multiple regression analysis showed that the administration of EPA was a significant and independent factor associated with an annual improvement of mean IMT (R2=0.067). In summary, this is the first demonstration that administration of purified EPA improves the carotid IMT and the baPWV in patients with type 2 diabetes.

Amelioration of glucose tolerance by hepatic inhibition of nuclear factor kappaB in db/db mice

AIMS/HYPOTHESIS

Recent studies have identified the involvement of inhibitor IkappaB kinase (IKK) in the pathogenesis of insulin resistance. To investigate the mechanism involved, we examined the role of nuclear factor kappaB (NF-kappaB), the distal target of IKK, in hepatic glucose metabolism.

METHODS

To inhibit NF-kappaB activity, db/db mice were infected with adenovirus expressing the IkappaBalpha super-repressor.

RESULTS

The IkappaBalpha super-repressor adenovirus infection caused a moderate reduction of NF-kappaB activity in liver. The treatment was associated with improved glucose tolerance, reduction in the serum insulin level, and increased hepatic triacylglycerol and glycogen contents, but had no effect on insulin-stimulated phosphorylation of Akt. On the other hand, quantification of mRNA in the liver revealed marked reduction of expression of gluconeogenic genes, such as those encoding phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase, concurrent with reduced expression of gene encoding peroxisome proliferator-activated receptor gamma coactivator-1alpha (PPARGC1A, also known as PGC-1alpha). Furthermore, the production of super-repressor IkappaBalpha suppressed the increase in blood glucose level after pyruvate injection.

CONCLUSIONS/INTERPRETATION

Our results indicate that moderate inhibition of NF-kappaB improved glucose tolerance through decreased gluconeogenesis associated with reduced PGC-1alpha gene expression in db/db mice, and suggest that inhibition of NF-kappaB activity in liver is a potentially suitable strategy for the normalisation of blood glucose concentration in type 2 diabetes.

The NR4A orphan nuclear receptor NOR1 is induced by platelet-derived growth factor and mediates vascular smooth muscle cell proliferation

Members of the nuclear hormone receptor superfamily function as key transcriptional regulators of inflammation and proliferation in cardiovascular diseases. In addition to the ligand-dependent peroxisome proliferator-activated receptors and liver X receptors, this family of transcription factors includes a large number of orphan receptors, and their role in vascular diseases remains to be investigated. The neuron-derived orphan receptor-1 (NOR1) belongs to the ligand-independent NR4A subfamily, which has been implicated in cell proliferation, differentiation, and apoptosis. In this study, we demonstrate NOR1 expression in vascular smooth muscle cells (SMC) of human atherosclerotic lesions. In response to mitogenic stimulation with platelet-derived growth factor (PDGF), SMC rapidly express NOR1 through an ERK-MAPK-dependent signaling pathway. 5'-deletion analysis, site-directed mutagenesis, and transactivation experiments demonstrate that PDGF-induced NOR1 expression is mediated through a cAMP-response element-binding protein (CREB)-dependent transactivation of the NOR1 promoter. Consequently, short interfering RNA-mediated depletion of CREB abolished PDGF-induced NOR1 expression in SMC. Furthermore, PDGF induced Ser-133 phosphorylation of CREB and subsequent binding to the CRE sites of the endogenous NOR1 promoter. Functional analysis demonstrated that PDGF induces NOR1 transactivation of its consensus NGFI-B-response elements (NBRE) in SMC. We finally demonstrate that SMC isolated from NOR1-deficient mice exhibit decreased cell proliferation and characterize cyclin D1 and D2 as NOR1 target genes in SMC. These experiments indicate that PDGF-induced NOR1 transcription in SMC is mediated through CREB-dependent transactivation of the NOR1 promoter and further demonstrate that NOR1 functions as a key transcriptional regulator of SMC proliferation.

Activation of peroxisome proliferator-activated receptor gamma suppresses telomerase activity in vascular smooth muscle cells

Activation of the peroxisome proliferator-activated receptor (PPAR) gamma, the molecular target for insulin sensitizing thiazolidinediones used in patients with type 2 diabetes, inhibits vascular smooth muscle cell (VSMC) proliferation and prevents atherosclerosis and neointima formation. Emerging evidence indicates that telomerase controls key cellular functions including replicative lifespan, differentiation, and cell proliferation. In the present study, we demonstrate that ligand-induced and constitutive PPARgamma activation inhibits telomerase activity in VSMCs. Telomerase reverse transcriptase (TERT) confers the catalytic activity of telomerase, and PPARgamma ligands inhibit TERT expression through a receptor-dependent suppression of the TERT promoter. 5'-deletion analysis, site-directed mutagenesis, and transactivation studies using overexpression of Ets-1 revealed that suppression of TERT transcription by PPARgamma is mediated through negative cross-talk with Ets-1-dependent transactivation of the TERT promoter. Chromatin immunoprecipitation assays further demonstrated that PPARgamma ligands inhibit Ets-1 binding to the TERT promoter, which is mediated at least in part through an inhibition of Ets-1 expression by PPARgamma ligands. In VSMCs overexpressing TERT, the efficacy of PPARgamma ligands to inhibit cell proliferation is lost, indicating that TERT constitutes an important molecular target for the antiproliferative effects of PPARgamma ligands. Finally, we demonstrate that telomerase activation during the proliferative response after vascular injury is effectively inhibited by PPARgamma ligands. These findings provide a previously unrecognized mechanism for the antiproliferative effects of PPARgamma ligands and support the concept that PPARgamma ligands may constitute a novel therapeutic approach for the treatment of proliferative cardiovascular diseases.

Polymorphism of the solute carrier family 12 (sodium/chloride transporters) member 3, SLC12A3, gene at exon 23 (+78G/A: Arg913Gln) is associated with elevation of urinary albumin excretion in Japanese patients with type 2 diabetes: a 10-year longitudinal study

AIMS/HYPOTHESIS

We have shown previously that the SLC12A3 +78G/A polymorphism in exon 23 (Arg913Gln) was a new candidate for conferring susceptibility to diabetic nephropathy. The aim of this study was to confirm the effect of this polymorphism on the elevation of urinary albumin excretion in type 2 diabetic patients.

METHODS

We retrospectively studied 264 Japanese patients with type 2 diabetes over a ten-year period. The subjects were classified into two groups: (1) persistent normoalbuminuria or microalbuminuria, or improvement from microalbuminuria to normoalbuminuria (group N); and (2) progression from normoalbuminuria to microalbuminuria or overt proteinuria, or progression from microalbuminuria to overt proteinuria (group P). They were assessed for association with the +78G/A polymorphism.

RESULTS

The frequency of the +78A allele was significantly higher in group N than in group P (10% vs 1%, p=0.021). By logistic regression analysis and discriminant analysis, the substituted allele was shown to be an independent factor correlating negatively to the elevation of albumin excretion (p=0.043 and 0.022, respectively).

CONCLUSIONS/INTERPRETATION

The SLC12A3 +78A(+) genotype may have a protective effect against the development and/or progression of diabetic nephropathy in Japanese type 2 diabetic patients.

Association between LDL particle size and postprandial increase of remnant-like particles in Japanese type 2 diabetic patients

Small, dense LDL, as well as chylomicron- and VLDL-remnant lipoproteins, are known to be important risk factors for coronary heart disease in patients with type 2 diabetes mellitus. The aim of this study was to clarify the relationship between LDL particle size and postprandial remnant lipoprotein levels in Japanese type 2 diabetic patients. Forty-six patients with type 2 diabetes mellitus were divided into tertiles according to LDL particle size. The peak LDL particle diameter was <26.30 nm in tertile 1, 26.30-26.85 nm in tertile 2, and >26.85 nm in tertile 3. After a test meal, tertile 1 had a significantly greater increment of triglycerides (TG), remnant-like particle (RLP)-TG, and RLP-cholesterol (RLP-C) than tertiles 2 and 3. There was a negative correlation between LDL particle size and the postprandial increases of TG, RLP-TG, and RLP-C. These results indicate that smaller sized LDL particles may be a marker of fasting state for an exaggerated postprandial increase of remnant lipoproteins as well as an increase of TG-rich lipoproteins.

Reduction of insulin-stimulated glucose uptake by peroxynitrite is concurrent with tyrosine nitration of insulin receptor substrate-1

Inducible nitric oxide synthetase plays an essential role in insulin resistance induced by a high-fat diet. The reaction of nitric oxide with superoxide leads to the formation of peroxynitrite (ONOO-), which can modify several proteins. In this study, we investigated whether peroxynitrite impairs insulin-signalling pathway. Our experiments showed that 3-(4-morpholinyl)sydnonimine hydrochloride (SIN-1), a constitutive producer of peroxynitrite, dose-dependently inhibited insulin-stimulated glucose uptake. While SIN-1 did not affect the insulin receptor protein level and tyrosine phosphorylation, it reduced the insulin receptor substrate-1 (IRS-1) protein level, and IRS-1 associated phosphatidylinositol-3 kinase (PI-3 kinase) activity. Although SIN-1 did not induce Ser307 phosphorylation of IRS-1, tyrosine nitration of IRS-1 was detected in SIN-1-treated-Rat1 fibroblasts expressing human insulin receptors. Mass spectrometry showed that peroxynitrite induced at least four nitrated tyrosine residues in rat IRS-1, including Tyr939, which is critical for association of IRS-1 with the p85 subunit of PI-3 kinase. Our results suggest that peroxynitrite reduces the IRS-1 protein level and decreases phosphorylation of IRS-1 concurrent with nitration of its tyrosine residues.

Functional effects of NAD(P)H oxidase p22phox C242T mutation in human leukocytes and association with thrombotic cerebral infarction

BACKGROUND

Previous study showed that polymorphism of the NAD(P)H oxidase p22(phox) gene is associated with atherosclerosis, although others could not confirm such association. We investigated the association between p22(phox) C242T polymorphism and thrombotic cerebral infarction and the role of this polymorphism on superoxide-production activity in human neutrophils and promyelocytic HL-60 cells as a model system.

METHODS

PCR-RFLP analysis revealed that genotype and allele frequencies of C242T polymorphism in 120 patients with thrombotic cerebral infarction and 177 control subjects. The superoxide-production activity in neutrophils was determined by cytochrome c reduction assay. To clarify the role of p22(phox) C242T polymorphism on NAD(P)H oxidase activity, we used transgenic HL-60 cells transfected with expression plasmids carrying p22(phox) cDNAs with or without C242T polymorphism.

RESULTS

Genotype and allele frequencies of C242T polymorphism in patients and control subjects were not significantly different. The superoxide-production activity in neutrophils with T allele was higher than in neutrophils without T allele. Moreover, expression analysis showed that superoxide-production activity in p22(phox) C242T-expressing HL-60 cells were significantly higher than in p22(phox)-expressing HL-60 cells.

CONCLUSIONS

We conclude that C242T of p22(phox) gene is not involved in thrombotic cerebral infarction but more likely in increased NAD(P)H oxidase activity in phagocytes.

Accumulation of somatic mutation in mitochondrial DNA and atherosclerosis in diabetic patients

A point mutation of mitochondrial DNA at nucleotide position 3243 A to G is responsible for the genetic cause of diabetes. Otherwise, this mutation is also reported to occur as a somatic mutation, possibility because of oxidative stress. Because diabetes may cause oxidative stress, we hypothesized that accumulation of the somatic A3243G mutation in mitochondrial DNA may be accelerated by diabetes. DNA was extracted from blood samples of 290 nondiabetic healthy subjects (aged 0-60 years) and from 383 type 2 diabetic patients (aged 18-80 years). Then, the extent of somatic A3243G mutation in total mitochondrial DNA was detected by real-time polymerase chain reaction (PCR) using the TaqMan probe. The genotyping of ACE I/D or p22phox C242T was done by PCR or PCR-restriction fragment length polymorphism. Although the level of the A3243G mutation was negligible in the newborn group, it increased in healthy subjects aged 20-29 and 41-60 years. In diabetic patients, the mutational rate increased along with age and the duration of diabetes. In the middle-aged group (41-60 years old), the A3243G mutation accumulates fourfold higher in the diabetic patients than in the healthy subjects. Moreover, multiple regression analysis revealed that the most critical factor associated with this mutation in diabetic patients was the duration of diabetes. Furthermore, the genotype of DD, DI-CC (ACE-p22phox) has the highest mutational rate and the thickest intima-media thickness of the carotid artery. In conclusion, diabetes accelerates the accumulation of the somatic A3243G mutation in mitochondrial DNA, and this somatic mutation may be a marker for the duration of diabetes and atherosclerosis.

Accumulation of somatic mutation in mitochondrial DNA and atherosclerosis in diabetic patients

A point mutation of mitochondrial DNA at nucleotide position 3243 A to G is responsible for the genetic cause of diabetes. Otherwise, this mutation is also reported to occur as a somatic mutation, possibility because of oxidative stress. Because diabetes may cause oxidative stress, we hypothesized that accumulation of the somatic A3243G mutation in mitochondrial DNA may be accelerated by diabetes. DNA was extracted from blood samples of 290 nondiabetic healthy subjects (aged 0-60 years) and from 383 type 2 diabetic patients (aged 18-80 years). Then, the extent of somatic A3243G mutation in total mitochondrial DNA was detected by real-time polymerase chain reaction (PCR) using the TaqMan probe. The genotyping of ACE I/D or p22phox C242T was done by PCR or PCR-restriction fragment length polymorphism. Although the level of the A3243G mutation was negligible in the newborn group, it increased in healthy subjects aged 20-29 and 41-60 years. In diabetic patients, the mutational rate increased along with age and the duration of diabetes. In the middle-aged group (41-60 years old), the A3243G mutation accumulates fourfold higher in the diabetic patients than in the healthy subjects. Moreover, multiple regression analysis revealed that the most critical factor associated with this mutation in diabetic patients was the duration of diabetes. Furthermore, the genotype of DD, DI-CC (ACE-p22phox) has the highest mutational rate and the thickest intima-media thickness of the carotid artery. In conclusion, diabetes accelerates the accumulation of the somatic A3243G mutation in mitochondrial DNA, and this somatic mutation may be a marker for the duration of diabetes and atherosclerosis.

Six year observational cohort study of the effect of carbon disulphide on brain MRI in rayon manufacturing workers

AIMS

To clarify whether the current occupational exposure limit (OEL) for carbon disulphide (CS2) is low enough to prevent the occurrence of adverse effects on the cerebrovascular system.

METHODS

A total of 432 male workers exposed to CS2 and 402 male referent workers in 11 Japanese viscose rayon factories were studied at baseline; 750 of these were followed up. Brain MRI was performed at both baseline and follow up surveys. Changes in the number of hyperintense spots in T2 weighted images (HIS), which point to so-called "silent cerebral infarctions", were evaluated over six years. A total of 666 subjects (217 exposed, 125 ex-exposed, and 324 referent subjects) who twice received brain MRI were subjected to analysis. Mean duration of exposure to the end of the study was 19.6 years for the exposed workers. The geometric mean CS2 (ppm) and TTCA (mg/g creatinine) concentrations for the past six years were 4.9 and 1.6 for all exposed workers, 5.8 and 1.9 for spinning/refining workers, and 2.7 and 0.9 for other exposed workers, respectively.

RESULTS

Exposed subjects showed a significantly higher risk for an increase in the number of HIS over six years. Odds ratios adjusted for possible confounders in the exposed and ex-exposed workers were 2.27 (95% CI 1.37 to 3.76) and 1.33 (95% CI 0.70 to 2.54), respectively. No exposure-response relations were observed in a number of analyses among the exposed workers.

CONCLUSIONS

Exposure to CS2 under the current Japanese OEL, 10 ppm, might increase the number of HIS in brain MRI. However, results should be interpreted with caution.

A six year follow up study of the subclinical effects of carbon disulphide exposure on the cardiovascular system

AIMS

A six year prospective cohort study was conducted to clarify whether the current carbon disulphide (CS2) exposure level is low enough to prevent subclinical health impairment and/or to ameliorate health effects due to previous high exposure. This paper describes the effects on the cardiovascular systems.

METHODS

The study subjects were 432 male workers exposed to CS2 and 402 non-exposed workers in Japan, all of whom were examined in 1992-93. A total of 251 CS2 exposed, 140 formerly exposed, and 359 non-exposed workers participated in the follow up survey (follow up rate 89.9%) in 1998-99. Mean duration of exposure was 19.3 years at the end the study. Mean CS2 and 2-thiothiazolidine-4-carboxylic acid (TTCA) concentrations were 5.0 ppm and 1.6 mg/g creatinine. Health items examined were serum biochemical indices including lipids and coagulation-fibrinolysis factors, blood pressure, aortic stiffness, ophthalmography, and electrocardiography at rest and after Master's double 2 step test. Potential confounding factors were adjusted for.

RESULTS

Incidence of ischaemic findings, defined as Minnesota codes I, IV(1-3), V(1-3) (at rest and after the load), or receiving treatment for ischaemia, was significantly higher in the exposed workers, especially for the spinning/refining workers (adjusted OR 2.1; 95% CI 1.1 to 4.0) or the highest quartile of six year mean TTCA (adjusted OR 3.9; 95% CI 1.8 to 8.7), although the observed increase in risk was diminished when rigorous ECG criteria were applied. Incidence of retinal microaneurysm was increased with marginal significance. Among cardiovascular risk factors we examined, only blood pressure values were significantly increased in the exposed workers.

CONCLUSIONS

Increased risk of ischaemic electrocardiogram findings among Japanese viscose rayon workers was observed. Although its clinical significance is to be discussed, the current Japanese occupational exposure limit for CS2, 10 ppm, would be high to prevent subclinical cardiovascular effects in this study population.

p38 MAPK is involved in activin A- and hepatocyte growth factor-mediated expression of pro-endocrine gene neurogenin 3 in AR42J-B13 cells

Neurogenin3 (ngn3) is a transcription factor that is essential for the differentiation of pancreatic endocrine cells. To investigate the signaling pathway that regulates ngn3 expression, we used AR42J-B13 cells as a model of the differentiation of pancreatic islets. In these cells, treatment with activin A and hepatocyte growth factor (HGF) induced the expression of ngn3. Reporter gene analysis using human ngn3 gene (NEUROG3) promoter fragments of various lengths identified the region between -402 and -327 bp of NEUROG3 as an activin A- and HGF-responsive DNA sequence. This DNA sequence normally functions as a repressor in AR42J-B13 cells, but treatment with activin A and HGF negates the repressor activity. Interestingly, function of the activin A- and HGF-responsive sequence was not influenced by the overexpression of the Smad inhibitory factor, Smad7. Instead, activin A and HGF activation was inhibited by overexpression of a dominant-negative mutant of transforming growth factor-beta-activated kinase 1 (TAK1), or mitogen-activated protein kinase kinase 3 (MKK3), or by treatment with a p38 MAPK-specific inhibitor, SB203580. Activin A and HGF function through the TAK1-MKK3-p38 MAPK pathway to relieve transcription repressors located between -402 and -326 bp on the NEUROG3 promoter, and consequently activate ngn3 expression and endocrine differentiation of AR42J-B13 cells.

The polymorphism of manganese superoxide dismutase is associated with diabetic nephropathy in Japanese type 2 diabetic patients

We evaluated the relationship of an alanine or valine polymorphism at amino acid sequence 16 [Val(16)Ala] of manganese superoxide dismutase (Mn-SOD) with diabetes and diabetic nephropathy in Japanese type 2 diabetic patients. Val(16)Ala genotyping of Mn-SOD was done by polymerase chain reaction-restriction fragment length polymorphism with a restriction enzyme ( Bsaw I) in 478 Japanese type 2 diabetic patients and 261 nondiabetic Japanese healthy subjects. The genotype distribution of diabetic and nondiabetic subjects was then compared, and the association of genotype with diabetic nephropathy was evaluated in the diabetic patients. The allele frequency and genotype of the diabetic patients were not different from those of the healthy nondiabetic subjects. The VV type showed a significantly higher frequency in the diabetic patients with nephropathy than did the AA or VA type [VV type: normoalbuminuria 70.8%, microalbuminuria 84.8% (P = 0.0057), macroalbuminuria 84.1% (P = 0.0128)]. Furthermore, logistic regression analysis showed that this polymorphism is associated with diabetic nephropathy independently (odds ratio = 0.461925, P = 0.03). Accordingly, the Val(16)Ala polymorphism of Mn-SOD may be unrelated to the etiology of type 2 diabetes, but it seems to be associated with diabetic nephropathy in Japanese type 2 diabetic patients.

Responsiveness of insulin-induced cardiac sympathetic nerve activation associates with blood pressure regulation in diabetics

To quantitatively evaluate the effect of insulin on cardiac sympathetic nerve activity (SNA) and analyze clinical factors associated with insulin sensitivity for the regulation of SNA in diabetics, 29 Japanese type 2 diabetics without neuropathy were recruited. A 2-h control study and a 2-h hyperinsulinemic euglycemic glucose clamp study were performed. From the power spectral analysis of R-R intervals on ECG during both studies, two major components, the low-frequency (LF) and the high-frequency component (HF), were obtained. Then %LF was calculated as LF/(LF +HF), and the ratio of the average %LF during the last 30 min of the clamp or the control to the average %LF for the entire time for clamp or control (R-%LF) was used as a marker of changes in SNA. R-%LF was significantly higher during the clamp than in the control (1.07 +/- 0.04 vs. 1.03 +/- 0.03, P < 0.05). High responders (individual R-%LF during clamp > or = mean + 2SD in control) showed a higher basal mean blood pressure (BP) before the clamp (89 +/- 3 vs. 82 +/- 2, P < 0.03) but not a higher glucose infusion rate (GIR) compared with low responders (<mean + 2SD). Furthermore, R-%LF showed a positive correlation with basal mean BP (P < 0.02) but not with GIR. These data demonstrate that an acute insulin load stimulates cardiac SNA, and insulin sensitivity in the regulation of SNA may be associated with BP regulation independently of peripheral insulin sensitivity.

RANTES promoter genotype is associated with diabetic nephropathy in type 2 diabetic subjects

OBJECTIVE

To evaluate the effect of RANTES gene promoter polymorphism and RANTES receptor (CCR5 gene) promoter polymorphism on diabetic nephropathy in Japanese type 2 diabetic subjects.

RESEARCH DESIGN AND METHODS

A total 616 Japanese subjects with type 2 diabetes were recruited. Polymorphisms of -28 C/G and -403 G/A in the RANTES gene promoter region, and of 59029 G/A in the CCR5 gene promoter region were detected by PCR-RFLP (restriction fragment length polymorphism). The association of these genotypes with nephropathy was analyzed.

RESULTS

While the RANTES -403 genotype showed no association with nephropathy, the frequency of the -28G allele was significantly higher in the DN2 group (urinary albuminuria-to-creatinine ratio [ACR] >or=300 mg/g creatinine, serum creatinine <2.0 mg/dl) than in the DN0 (ACR <30 mg/g creatinine) and DN1 (ACR >or=30 mg/g creatinine and <300 mg/g creatinine) groups. The frequency of a RANTES -28G-positive genotype (C/G or G/G) was higher in the DN2 group than in the DN0 and DN1 groups (34% vs. 25 and 20%, P = 0.0268, chi(2) = 4.905), and the frequency of a CCR5 59029 A-positive genotype (G/A or A/A) was higher in the DN1 and DN2 groups than in the DN0 group (84 and 85% vs. 76%, P = 0.0123, chi(2) = 6.269). Discriminant analysis showed that the RANTES -28G-positive genotype and CCR5 59029A-positive genotype were independently associated with nephropathy. The percentage of macroalbuminuria was twofold higher in the subjects having -28G or 59029A and threefold higher in the subjects having -28G and 59029A than in the subjects without -28G and 59029A.

CONCLUSIONS

The RANTES promoter -28G genotype and CCR5 promoter 59029A genotype may be independent risk factors for diabetic nephropathy in patients with type 2 diabetes and may have an additive effect on nephropathy.

Lead induced increase of blood pressure in female lead workers

AIMS

Although lead exposure has, in the absence of mathematical modelling, been believed to elevate blood pressure in females, it is necessary to clarify the relation between lead and blood pressure by eliminating confounding factors in the analysis.

METHODS

Blood lead was measured in 193 female workers, including 123 lead exposed workers. Possible confounding factors were controlled by multiple regression analyses.

RESULTS AND CONCLUSIONS

Blood lead above 40 micro g/dl was found to be the most potent factor for elevating systolic/diastolic blood pressure. Aging, urine protein, and plasma triglyceride also contributed to systolic/diastolic/pulse pressure increase, but hypertensive heredity did not. Data suggested that lead induced changes in lipoprotein metabolism may play an important role in the lead induced blood pressure increase in female workers.

Accumulation of somatic mutation in mitochondrial DNA extracted from peripheral blood cells in diabetic patients

AIMS/HYPOTHESIS

A point mutation of mitochondrial DNA at nucleotide number 3243 A to G is responsible for both the major genetic aetiologies of the MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) and mitochondrial diabetes. Otherwise, this mutation is also reported to occur as an acquired somatic mutation, possibly due to oxidative stress. Since diabetes can cause severe oxidative stress, we hypothesize that the accumulation of the somatic 3243 A to G mutation in mitochondrial DNA can be accelerated by diabetes.

METHODS

DNA was extracted from blood samples of 290 non-diabetic healthy subjects (age 20-60) including 98 newborn infants and from 383 patients with Type II (non-insulin-dependent) diabetes mellitus (age 18-80). The extent of somatic 3243 A to G mutation to total mitochondrial DNA was detected by real-time PCR using the TaqMan Probe.

RESULTS

Whereas the level of the 3243 A to G mutation was negligible in the newborn group, it was increased in healthy subjects who were 20 to 29 and 41 to 60 years of age, suggesting that this mutation was somatic. In the diabetic patients the mutation rate increased along with age and the duration of diabetes. In the middle-aged group (age 41-60), the 3243 A to G mutation accumulates fourfold higher in the diabetic patients than the healthy subjects. Moreover, multiple regression analysis showed that the most critical factor associated with this mutation in diabetic patients was the duration of diabetes.

CONCLUSION/INTERPRETATION

Diabetes accelerates the accumulation of the somatic 3243 A to G mutation in mitochondrial DNA, which can accelerate the ageing process. This somatic mutation could possibly be a new marker for estimating the duration of diabetes.

Chemokine receptor genotype is associated with diabetic nephropathy in Japanese with type 2 diabetes

Glomerular infiltration of monocytes/macrophages occurs in diabetic patients with nephropathy, and chemokine receptor signals are thought to play a key role in the development of nephropathy. Recently, polymorphism of the chemokine receptor (CCR)2 coding region V64I and the CCR5 promoter region 59029 (G/A) have been identified. Accordingly, we evaluated the effects of these genotypes on diabetic nephropathy. CCR2 V64I and CCR5 59029 (G/A) were detected by polymerase chain reaction-restriction fragment-length polymorphism in 401 patients with type 2 diabetes who had a serum creatinine <2.0 mg/dl. Although the CCR2 V64I genotype showed no association with nephropathy, the frequency of the CCR5 59029 A-positive genotype (G/A or A/A) was significantly higher in patients with microalbuminuria (urinary albumin-to-creatinine ratio [ACR] > or = 30 and <300 mg/gCre, 86%) and patients with macroalbuminuria (ACR > or = 300 mg/gCre, 87%) than in patients with normoalbuminuria (ACR <30 mg/gCre, 75%; P = 0.0095). Polytomic logistic regression analysis showed that the CCR5 59029 A-positive genotype was associated with nephropathy (odds ratio 2.243, P = 0.0074). These results suggest that the CCR5 promoter 59029 A genotype may be an independent risk factor for diabetic nephropathy in patients with type 2 diabetes.

[Immunohistochemical study of idiopathic and secondary epiretinal membrane]

PURPOSE

We investigated the immunohistochemical features of surgically resected idiopathic epiretinal membranes(ERMs) and secondary ERMs with regard to posterior vitreous detachment(PVD).

METHODS

Six specimens of idiopathic epiretinal membranes(3 eyes with complete PVD, 2 eyes with partial PVD, and one eye with no PVD) and 3 specimens of secondary ERMs(all eyes with complete PVD) were immunohistochemically studied. We used type I, II, III, IV collagen and fibronectin to study extracellular components, and glial fibrillary acidic protein(GFAP), S 100 protein, vimentin, and so forth to study cellular components.

RESULTS

All the specimens of idiopathic ERMs had the major components of the lamellar stained by type II collagen antibody, and one out of 3 specimens of secondary ERMs had a minor component stained by type II collagen antibody. Compared with idiopathic ERMs with complete PVD, 2 out of 3 specimens of idiopathic ERMs with partial PVD or no PVD contained rather thick collagen lamellar.

CONCLUSION

There was difference between specimens of idiopathic ERMs and specimens of secondary ERMs in staining by type II collagen antibody, supposed by vitreous, in this study. Idiopathic ERM with attached posterior vitreous membrane may cause growth of collagen.

Insertion polymorphism of CYP2E1 and urinary N-methylformamide after N,N- dimethylformamide exposure in Japanese workers

OBJECTIVES

This study examined whether consideration of the *1C/*1D CYP2E1 insertion polymorphism is important for interpreting the biological monitoring of exposure to N,N-dimethylformamide (DMF) in Japanese workers.

METHODS

The insertion genotype, airborne DMF exposure on the last day of a work week, and NMF in urine sampled just after the last workshift of the week were determined in 44 male and female Japanese workers.

RESULTS AND CONCLUSIONS

The allelic frequency of this CYP2E1 polymorphism was 0.261 in this Japanese population of workers. The CYP2E1 insertion polymorphism did not contribute to NMF levels even after consideration of BMI or alcohol intake. The results indicate that CYP2E1 insertion polymorphism does not appear to be an important determinant for the interpretation of biological exposure to DMF by the measurement of urinary NMF.

Investigations on the liver toxicity of a blend of HCFC-123 (2,2-dichloro-1,1,1-trifluoroethane) and HCFC-124 (2-chloro-1,1,1,2-tetrafluoroethane) in guinea-pigs

2,2-Dichloro-1,1,1-trifluoroethane (HCFC-123) has been developed as a substitute for ozone-depleting chlorofluorocarbons (CFCs). It is a structural analogue of halothane and similarities in the metabolic pathways and liver toxicity of both compounds have been described. The present study was initiated after an accidental outbreak of hepatitis in an industrial setting to examine whether concomitant exposure to 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124), which is not hepatotoxic, could enhance the liver toxicity of HCFC-123. Male Hartley guinea-pigs were exposed for 4 h to 5,000 ppm HCFC-123 alone or blended with 5,000 ppm HCFC-124, either once (single exposure) or on 5 consecutive days (repeated exposure). The animals were killed either 24 or 48 h after the last exposure. A transient cytolytic action of HCFC-123 was evident by increased mean serum levels of alanine aminotransferase at 24 h and isocitrate dehydrogenase at 24 and 48 h, both after a single or repeated exposure. The liver toxicity of HCFC-123 was confirmed by pathological examination of liver tissue, which showed mild (foci of necrotic hepatocytes) to moderate (multifocal random degeneration and necrosis) damage. Steatosis was also observed and was more pronounced after repeated exposure than after single. One animal out of 6 that were repeatedly exposed to the blend and sacrificed at 24 h showed liver lesions similar to halothane hepatitis. Although a few other animals responded markedly in the blend-treated group, on average, no significant difference in the biochemical or pathological lesions was found between the groups treated with HCFC-123 alone or with the blend. Urinary excretion of trifluoroacetic acid and chlorodifluoroacetic acid increased dose-dependently upon exposure to HCFC-123 and indicated accumulation after repeated exposure. No difference in metabolite excretion was found between animals treated with HCFC-123 alone or blended with HCFC-124. Treatment with HCFC-123 depleted hepatic glutathione levels by about 40 and 25% after single and repeated exposure, respectively; the amplitude of this reduction was not modified by co-exposure to HCFC-124. In conclusion, this study confirmed the hepatotoxicity of HCFC-123, based on biochemical, histopathological and metabolite studies, and found only very limited indication of a potentiation by HCFC-124 of this hepatotoxic effect.

Eosinophilic pustular folliculitis in association with nevoid basal cell carcinoma syndrome

This study reports on the clinical and light microscopic features of a nevoid basal cell carcinoma syndrome with the complication of eosinophilic pustular folliculitis. To the authors' knowledge, this is the first report of such an association, which is possibly due to immune dysregulation. Moreover, the patient experienced remission of eosinophilic pustular folliculitis after removal of the jaw cyst. One possible explanation for the remission is that a long-lasting TH, type inflammatory response as a result of the bone defect produces effective cytokines such as interferon-gamma.

N , N -Dimethylformamide: significance of dermal absorption and adjustment method for urinary N -methylformamide concentration as a biological exposure item

OBJECTIVES

To clarify the potential for dermal absorption of N,N-dimethylformamide (DMF) (CAS No. 68-12-2) vapor, and the appropriate adjustment method and the half-lives of urinary concentrations of N-methylformamide (NMF) as the biological exposure item of DMF.

METHODS

Thirteen healthy male volunteers (mean age: 22.7 years, range: 20-27) were exposed to DMF vapor twice, via both the skin and the lung, for 4 h at concentrations below 10 ppm, the recommended occupational exposure limit set by the Japan Society for Occupational Health, the American Conference of Governmental and Industrial Hygienists, and Deutsche Forschungsgemeinschaft, under conditions of 27 degrees C and 44% humidity. Each volunteer was exposed to DMF via the skin in a whole-body type exposure chamber and outside the chamber, via the lung by a respirator connected to the chamber. Exposure levels were 6.2 +/- 1.0 ppm in dermal exposure and 7.1 +/- 1.0 ppm in inhalation exposure. Urine samples were collected at every opportunity until 72 h after exposure; and NMF, as well as volume, creatinine, and specific gravity were measured. Dermal and inhalation intakes were compared after adjusting concentrations.

RESULTS AND CONCLUSIONS

DMF vapor absorptions via the skin and the lung were estimated to be 40.4 and 59.6%, respectively. Workers need to be aware of the risk of dermal absorption of DMF vapor as well as of the liquid. Though NMF concentrations adjusted by creatinine, specific gravity, and urinary volume showed good correlation with total NMF excretion and the absolute amount of NMF at each sampling time, creatinine-adjusted NMF concentration correlated better than the others. The biological half-life of urinary NMF after dermal exposure, 4.75 +/- 1.63 h, was longer than that after respiratory exposure, 2.42 +/- 0.63 h.

Antiatherogenic mitochondrial genotype in patients with type 2 diabetes

OBJECTIVE

To evaluate the significance of a longevity-associated mitochondrial genotype (Mt5178A) derived from a C --> A transversion at nucleotide position 5178 of mitochondrial DNA, which causes a Leu-to-Met substitution within the NADH dehydrogenase subunit 2 gene, in type 2 diabetic subjects.

RESEARCH DESIGN AND METHODS

Mt5178 typing was done by polymerase chain reaction-restriction fragment-length polymorphism with the restriction enzyme AluI in 1,148 type 2 diabetic Japanese subjects, and the results were compared with the clinical characteristics. Then, the association of Mt5178 type with early atherosclerotic changes of the bilateral carotid arteries on ultrasonography was assessed in 412 diabetic subjects randomly selected from the original 1,148 type 2 diabetic subjects, while maintaining the same frequency of Mt5178A and Mt5178C.

RESULTS

The frequency of Mt5178A in the type 2 diabetic subjects (454 of 1,148; 40%) was not different from that previously found in healthy blood donors (114 of 252; 45%). Clinical characteristics regarding diabetes were not significantly different between the Mt5178A group (n = 454) and the Mt5178C group (n = 694). However, the mean intima-media thickness (IMT) at six sites in the bilateral carotid arteries was significantly smaller in the Mrt5178A group than in the Mt5178C group (0.906 +/- 0.018 vs. 0.995 +/- 0.021 mm, mean +/- SEM, P = 0.022), and the Mt5178 type was significantly correlated with both the mean IMT and the presence of plaque on multiple regression analysis and discriminant analysis.

CONCLUSIONS

The Mt5178A genotype may be unrelated to the etiology of type 2 diabetes. However, Mt5178A seems to have an antiatherogenic effect, at least in type 2 diabetic individuals.

Does the polymorphism of cytochrome P-450 2E1 affect the metabolism of N,N-dimethylformamide? Comparison of the half-lives of urinary N-methylformamide

The aim of this study was to clarify whether phenotypic variation exists when subjects with different genotypes of cytochrome P450 2E1 (CYP2E1) are exposed to N,N-dimethylformamide (DMF). The genotypes of CYP2E1 were confirmed in 123 healthy male volunteer subjects. Of the 123 subjects, the numbers of c1 homozygotes, c2 heterozygotes, and c2 homozygotes were 77, 45, and 1, respectively. Seven of the c1 homozygotes, five of the c2 heterozygotes, and the one c2 homozygote (mean age: 22.7 years, range: 20-27 years) were exposed to DMF vapor twice, once via the skin and once via the lung, for a total of 8 h per subject at a concentration below 10 ppm, the occupational exposure limit recommended by the Japan Society for Occupational Health, the American Conference of Governmental and Industrial Hygienists, and Deutsche Forschungsgemeinschaft, at 27 degrees C and 44% relative humidity. Exposure levels were 6.2+/-1.0 ppm in dermal exposure and 7.1+/-1.0 ppm in inhalation exposure. Urine samples were collected until 72 h after exposure. The half-lives of urinary N-methylformamide (NMF) were obtained as the phenotype. The average urinary NMF half-lives of the c1 homozygotes, the c2 heterozygotes, and the c2 homozygote were 3.86+/-1.90, 4.38+/-1.53, and 4.2 h after dermal exposure, and 1.58+/-0.42, 1.84+/-0.61, and 3.2 h after respiratory exposure. The NMF half-lives of the c1 homozygotes were not significantly different from those of the c2 heterozygotes, and there were no differences between the NMF half-lives on the subjects with and without the c2 allele. Even though the data were obtained from only one c2 homozygote, it is noteworthy that the NMF half-life of this subject was slightly less than that of the c1 homozygotes after respiratory exposure.

Causal relationship between a case of severe hepatic dysfunction and low exposure concentrations of N,N-dimethylformamide in the synthetics industry

A 19-year-old man suffered hepatic dysfunction after 5 months of exposure to N,N-dimethylformamide (DMF) at his job in the synthetic resins industry. Laboratory data revealed elevated levels of AST (578 IU/l), ALT (1193 IU/l), and gamma-GTP (107 IU/l), no viral infection with HAV, HBV, or HCV, and no history or evidence of hepatic injury, although he did have a slight abdominal abnormality and swelling which was detected by palpation. His urinary N-methylformamide level, as a biological exposure index of DMF, was 42.8 mg/l, indicating 10-30 ppm of DMF exposure. After 2 months he was reinstated in two workplaces, the former where he worked in the morning and the other in the afternoon where environmental DMF concentrations were less than those in the former workplace. On the 18th day after his reinstatement, his liver function became exasperated again. After the second period of medication and one month of rest from work, he had fully recovered and was reinstated, but to a workshop without DMF exposure.

Immunocytochemistry of fibronectin and endothelin-1 in the cavernous body of postnatal rabbit penises

The differentiating cavernous body (CB) of postnatal rabbit penises was examined with a special reference to immunolocalizations for fibronectin (FN) and endothelin-1 (ET-1). At postnatal day 1, the CBs were embedded by an abundance of mesenchymal cells (MCs), and some of them were closely associated with endothelial cells of preexisting capillaries. Our electron micrographs indicated that such MCs are successively incorporated into the capillary endothelium as vasoformative cells. At this period, vascular sprouts of the helicine artery (HA), which were associated with the MCs, arose from the deep penile artery, and the transformation of such cells to endothelial and medial muscle ones was also indicated, and some MCs appeared to differentiate to epithelioid cells in the media. Immunoreactions for FN were preferentially localized in the rough endoplasmic reticulum (rER) and along the plasma membrane of such vasoformative MCs, and on the extracellular matrix components which connect these MCs with sprouts of both growing capillaries and HA. These findings suggest that FN, which is produced in the rER of the MCs, plays a crucial role in the mechanical linkage during the incorporation of vasoformative MCs into these penile vessels. Immunoreactions for ET-1 were preferentially localized on Weibel-Palade bodies in endothelial cells of the HA, implying the involvement of this peptide in the regulation of the local blood flow in this vessel.

Dermal absorption of N,N-dimethylacetamide in human volunteers

OBJECTIVES

We investigated the potential for the dermal absorption of N,N-dimethylacetamide (DMAC: CAS No. 127-19-5) vapor, the biological half-life of N-methylacetamide (NMAC) in urine as the biological exposure item of DMAC, and the adjustment method for urinary concentrations.

METHODS

Twelve healthy male volunteers (mean age 25.2 years, range 21-43 years) were exposed to DMAC for 4 h on two occasions at intervals of 96 h or above. Each volunteer sat inside a whole-body-type exposure chamber for the dermal exposure experiment or outside the chamber for the inhalation exposure experiment. The temperature and relative humidity in the chamber were controlled at approximately 26 degrees C and 40% in order to keep the skin (90% naked) of the volunteers dry. DMAC concentrations were 6.1 +/- 1.3 ppm for dermal exposure and 6.1 +/- 1.3 ppm for inhalation exposure. Urine samples were collected from 0 h through 36 h and at 48 h and 72 h after the exposure. Extrapolations from exposure concentrations for 4 h to 10 ppm for 8 h were performed.

RESULTS

Mean dermal absorption was estimated to be 40.4% of the total DMAC uptake. The biological half-lives of urinary NMAC were 9.0 +/- 1.4 h and 5.6 +/- 1.3 h via skin and lung, respectively. Mean NMAC in urine just after 5 consecutive workdays (8 h/day) at 10 ppm DMAC exposure was assumed to be 33.7 mg/g x Cr (18.6-70.0 mg/g x Cr). Creatinine-adjusted NMAC concentration in urine for each volunteer within 12 h after the exposure was more closely correlated with the total excretion amount of NMAC up to 36 h than with urinary-volume-adjusted or specific-gravity-adjusted NMAC concentration in both the dermal and inhalation exposure experiments.

CONCLUSIONS

DMAC vapor was significantly absorbed through the skin. Estimated NMAC values indicate that 20 mg/g x Cr NMAC seems to be appropriate as the biological exposure index.

Relationship between the blood coagulation-fibrinolysis system and the subclinical indicators of arteriosclerosis in a healthy male population

A cross-sectional observation was performed to assess the relationship between the coagulation-fibrinolysis system and the subclinical indicators of arteriosclerosis in a healthy male population. Subjects were 445 workers (18.9-49.4, Av. 36.2 yrs) in viscose rayon manufacturing factories in Japan. Coagulation-fibrinolysis parameters determined were D-dimer(DD), thrombin antithrombin III complex (TAT), tissue plasminogen activator (TPA), and plasminogen activator inhibitor 1 (PAI1). The following indicators of arteriosclerosis were examined; systolic and diastolic blood pressure (SBP, DBP), stiffness parameter of the carotid artery using ultrasound (beta), pulse wave velocity of the aorta (PWV), and a number of lacunar infarctions from brain MRI. After age-stratification(-29, 30-39, 40+ yrs), the subjects were classified into quartiles by coagulation-fibrinolysis parameters. The mean values of SBP and DBP and beta and PWV, the prevalence of brain infarctions were compared across these quartiles by means of analysis of variance, chi-square test, respectively. Multivariate analysis was also employed to adjust other risk factors. In conclusion, SBP and DBP and beta, PWV were elevated by increase of PAI1, TAT, respectively, in the 40+ years group even after adjustment for other possible risk factors. DD had no relation to any of the indicators of arteriosclerosis. None of the coagulation-fibrinolysis parameters had any relation to brain infarctions.

A cross-sectional observation of the health effects of hydrazine hydrate and differences of its metabolism by NAT2 polymorphism

OBJECTIVES

To summarize the results of two studies that attempted to clarify: (1) the health effects of hydrazine hydrate (HH) (N2H4 x H2O: CAS No. 7803-57-8); and (2) the influence of allelic polymorphism of N-acetyltransferase (NAT2) on the metabolism of HH.

METHODS

A cross-sectional survey was carried out on 172 male HH-exposed workers and 125 male referent workers at five factories in Japan. The biological half-lives of HH after 1 h of exposure were determined in 12 workers, four workers in each of three NAT2 phenotypes. Clinical examinations were performed and acute and chronic subjective symptoms related to HH were examined by self-administered questionnaires. NAT2 phenotypes were assessed.

RESULTS

No hydrazine was detected in either the breathing zones or the urine of the referent workers. The mean hydrazine concentration in the breathing zones, hydrazine and acetylhydrazine in urine, and the cumulative exposure level were 0.0109 ppm, 0.8660 micromol/g x Cr, and 2.80 ppm-years, respectively. There was no difference and no dose-dependent change in the health examination items between HH-exposed and referent workers after adjusting confounding factors, nor in terms of the differences of NAT2 phenotypes. Of 90 subjective symptoms, complaints of nightmares were significantly related to HH exposure. The half-life of urinary hydrazine and acetylhydrazine on rapid, intermediate, and slow phenotypes was 1.68, 3.01, and 4.46 h, respectively.

CONCLUSION

This study suggested that current and cumulative exposure to HH did not affect the workers' health, and the half-life of the slow phenotype was longer than those of the rapid and intermediate phenotypes.