市原 佐保子

1-Bromopropane (1-BP) has been used as an alternative to ozone-depleting solvents. Previous studies showed that 1-BP is neurotoxic in animals and humans. In humans, exposure to 1-BP caused various neurological and neurobehavioral symptoms or signs including depressive or irritated mood. However, the neurobiological changes underlying the depressive symptoms induced by 1-BP remain to be determined. The depressive symptoms are thought to be associated with degeneration of axons containing noradrenaline and serotonin. Based on this hypothesis, the present study examined the effects of repeated exposure to 1-BP on serotonergic and noradrenergic axons. Exposure to 1-BP induced dose-dependent decreases in the density of noradrenergic axons in the rat prefrontal cortex, but no apparent change in the density of serotonergic axons. The results suggest that depressive symptoms in workers exposed to 1-BP are due, at least in part, to the degeneration of noradrenergic axons in the brain.

Pleural plaques are asymptomatic focal thickenings of the pleura and considered the hallmark of asbestos exposure. However, it is often difficult to detect pleural plaques on chest x-rays (CXR). In a retrospective study, using chest CT scans of 140 Japanese asbestos-exposed construction workers who have probable or definite findings of pleural plaque on CXR; firstly, we proposed plaque morphology-based classification for CXR findings, and then we examined if those classified findings could be confirmed as pleural plaques on CT scans. Our morphology-based classification of pleural plaque findings included nine types. The percentages of confirmed pleural plaques on CT scans by type (number of confirmed pleural plaque on CT/number of observed on CXR) were 93% (40/43) for straight, 89% (56/63) for diamond, 88% (7/8) for double, 83% (19/23) for tapered medially, 80% (20/25) for parallel, 77% (23/30) for crescent, 79% (11/14) for tenting, 72% (18/25) for tapered-laterally (long type), and 0% (0/9) for tapered-laterally (short type). When added to the ILO classification, morphology-based classification of CXR pleural plaque findings makes its detection easier and hence chest radiograph continues to be a suitable tool for screening asbestos-related pleural plaques based on its simplicity, low radiation exposure, wide availability and cost-effectiveness.

OBJECTIVE: To investigate the potential role of nuclear factor-erythroid 2-related factor 2 (Nrf2) in neovascularization with a murine surgical model of ischemia. METHODS AND RESULTS: The transcription factor Nrf2 protects against oxidative stress by increasing the transcription of genes, including those for several antioxidant enzymes that contain an antioxidant response element. Ischemia was induced by femoral artery ligation in Nrf2-deficient (Nrf2(-/-)) and wild-type mice. Ischemia-induced neovascularization was enhanced in Nrf2(-/-) mice compared with that in wild-type mice. The expression of Nrf2 target genes for heme oxygenase 1 and thioredoxin 1 and the concentration of total glutathione in the ischemic hindlimb were reduced for Nrf2(-/-) mice compared with wild-type mice. The infiltration of inflammatory cells and the abundance of adhesion molecule mRNA were greater in the ischemic hindlimb of Nrf2(-/-) mice than in wild-type mice. The expression of monocyte chemoattractant protein-1, tumor necrosis factor-alpha, cyclooxygenase 2, and angiogenic factors in the ischemic hindlimb was also greater for Nrf2(-/-) mice than for wild-type mice. CONCLUSIONS: The ablation of Nrf2 promoted ischemia-induced neovascularization. This effect likely resulted from impaired antioxidant defense and increased accumulation of reactive oxygen species in endothelial cells; consequently, there was an enhanced inflammatory response.

OBJECTIVES: To investigate the health effects of 1-bromopropane (1-BP) and its dose-dependency in 1-BP production factories in China. METHODS: Data of 60 female and 26 male workers in three 1-BP factories and the same number of age-, sex-, and region-matched controls were interviewed and examined. The time-weighed average exposure levels of individual workers were estimated. RESULTS: Regression analysis on exposure level showed dose-dependent increase in the distal latency of tibial nerve, threshold for vibration sense in toes, lactate dehydrogenase, thyroid stimulating hormone, and follicle stimulating hormone in female workers. The analysis also showed dose-dependent decrease in sensory nerve conduction velocity of the sural nerve, red blood cell, and hematocrit in female workers. CONCLUSIONS: The results indicate that exposure to 1-BP induces dose-dependent neurotoxicity in female workers.

1-Bromopropane (1-BP) was introduced as an alternative to ozone-depleting solvents. However, it was found to exhibit neurotoxicity, reproductive toxicity, and hepatotoxicity in rodents and neurotoxicity in human. However, the mechanisms underlying the toxicities of 1-BP remain elusive. The present study investigated the role of oxidative stress in 1-BP-induced hepatotoxicity using nuclear factor erythroid 2-related factor 2 (Nrf2)-null mice. Groups of 24 male Nrf2-null mice and 24 male wild-type (WT) C57BL/6J mice were each divided into three groups of eight and exposed to 1-BP at 0, 100, or 300 ppm for 8 h/day for 28 days by inhalation. Liver histopathology showed significantly larger area of necrosis in Nrf2-null mice relative to WT mice at the same exposure level. Nrf2-null mice also had greater malondialdehyde (MDA) levels, higher ratio of oxidized glutathione/reduced form of glutathione, and lower total glutathione content. The constitutive level and the increase in ratio per exposure level of glutathione S-transferase (GST) activity were lower in the liver of Nrf2-null mice than WT mice. Exposure to 1-BP at 300 ppm increased the messenger RNA levels of heme oxygenase-1 (HO-1), glutamate-cysteine ligase modifier subunit (GcLm), glutamate-cysteine synthetase (GcLc), glutathione reductase, and NAD(P)H: quinone oxidoreductase 1 (NQO1) in WT mice but not in Nrf2-null mice except for GST Yc2. Nrf2-null mice were more susceptible to 1-BP-induced hepatotoxicity. That oxidative stress plays a role in 1-BP hepatotoxicity is deduced from the low expression levels and activities of antioxidant enzymes and high MDA levels in Nrf2-null mice.

1-Bromopropane (1-BP), an alternative to ozone-depleting solvents, exhibits neurotoxicity and reproductive toxicity in animals and humans. The present study investigated the effects of exposure to 1-BP on expression of neurotransmitter receptor genes in the rat brain to explore possible biomarkers for central neurotoxicity and find brain regions sensitive for microarray analysis. Thirty-six F344 rats were divided at random into four equal groups of nine and exposed to 1-BP at 0, 400, 800 and 1000 ppm for 8 h/day; 7 days/week for 4 weeks. Total RNA from different brain regions was extracted and real-time PCR was conducted to quantify the mRNA levels of serotonin, dopamine and GABA receptors. Western blot analysis for specific regions of interest was also carried out to determine the protein levels. The mRNAs of 5HTr2a, D2R and GABAa1 were down regulated in a 1-BP dose-dependent manner in the hippocampus. The mRNA levels of 5HTr1a, 5HTr2a, D1R and GABAa1 were significantly decreased in the cortex of rats exposed to 800 ppm, but not to 1000 ppm. The mRNAs of 5HTr1a and 5HTr3a in the pons-medulla were decreased in rats exposed to 400 ppm or higher concentrations. The mRNA expression of D2R in the hippocampus and 5HTr1a and 5HTr3a in the pons-medulla oblongata were the most sensitive indicators of 1-BP neurotoxicity. The results suggest that mRNA expression analysis is useful in identifying brain regions susceptible to 1-BP, as well as providing potential biomarkers for central nervous system toxicity.

Previous studies indicate that 1-bromopropane (1BP) has neurotoxicity and reproductive toxicity both in humans and animals. The present study investigated strain differences in susceptibility to 1BP and identified possible biological factors that determine such susceptibility. Twenty-four male mice of each of the three strains (C57BL/6J, DBA/2J, and BALB/cA) were divided into four groups of six each and exposed to 1BP at 0, 50, 110, and 250 ppm for 8 h/day for 28 days by inhalation. At the end of exposure period, the relative susceptibilities of each strain to 1BP-mediated hepatotoxicity and male reproductive toxicity were evaluated. The contributing factors to strain-dependent susceptibility were assessed by determination of hepatic CYP2E1 levels, glutathione-S-transferase (GST) activity, glutathione (GSH) status, and NAD(P)H:quinone oxidoreductase and heme oxygenase-1 mRNA levels. Liver histopathology showed significantly larger area of liver necrosis and more degenerative lobules in BALB/cA in the order of BALB/cA > C57BL/6J > DBA/2J. BALB/cA showed higher CYP2E1 protein level and lower total GSH content and GST activity in the liver than DBA/2J. These results indicate that BALB/cA mice are the most susceptible to hepatotoxicity of 1BP among the three strains tested, and that CYP2E1, GSH level/GST activity may contribute to the susceptibility to 1BP hepatotoxicity. Exposure to > or = 50 ppm of 1BP also decreased sperm count and sperm motility and increased sperms with abnormal heads in all three strains mice in a dose-dependent manner. Comparison with previous studies in rats indicates that mice are far more susceptible than rats to 1BP regarding hepatotoxicity and reproductive toxicity.

We have investigated the effect of benzo[a]pyrene (B[a]P), a carcinogen of tobacco smoke and an agonist for the aryl hydrocarbon receptor (AHR), on hypoxia-induced angiogenesis. Ischemia was induced by femoral artery ligation in wild-type and AHR-null mice, and the animals were subjected to oral administration of B[a]P (125 mg/kg) once a week. Exposure to B[a]P up-regulated the expression of metallothionein in the ischemic hindlimb and markedly inhibited ischemia-induced angiogenesis in wild-type mice. The amounts of interleukin-6 and of vascular endothelial growth factor (VEGF) mRNA in the ischemic hindlimb of wild-type mice were reduced by exposure to B[a]P. These various effects of B[a]P were markedly attenuated in AHR-null mice. Our observations suggest that the loss of the inhibitory effect of B[a]P on ischemia-induced angiogenesis apparent in AHR-null mice may be attributable to maintenance of interleukin-6 expression and consequent promotion of angiogenesis through up-regulation of VEGF expression.

BACKGROUND AND PURPOSE: Although genetic epidemiologic studies have implicated several genetic variants as risk factors for ischemic or hemorrhagic stroke, the genetic determinants of these conditions remain largely unknown. We performed an association study to identify gene polymorphisms that confer susceptibility to atherothrombotic cerebral infarction, intracerebral hemorrhage, or subarachnoid hemorrhage. METHODS: The study population comprised 3432 unrelated Japanese individuals: 1362 stroke patients (822 with atherothrombotic cerebral infarction, 333 with intracerebral hemorrhage, and 207 with subarachnoid hemorrhage) and 2070 controls. The genotypes for 50 polymorphisms of 38 candidate genes were determined by a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. RESULTS: An initial chi(2) test (false discovery rate <0.05) and subsequent multivariable logistic-regression analysis with adjustment for conventional risk factors (P<0.05) revealed that the -14C-->T polymorphism (rs1800977) of ABCA1, the A-->C (rs3027898) and C-->T (Ser532Leu, rs1059703) polymorphisms of IRAK1, and the G-->C (Cys2229Ser) polymorphism (rs619203) of ROS1 were significantly associated with atherothrombotic cerebral infarction; that the -428G-->A polymorphism (rs710968) of LIMK1 was significantly associated with intracerebral hemorrhage; and that the 13989A-->G (Ile118Val) polymorphism (NC_000007.12) of CYP3A4 was significantly associated with subarachnoid hemorrhage. CONCLUSIONS: Genotypes for ABCA1, IRAK1, and ROS1 may prove useful for assessment of the genetic risk for atherothrombotic cerebral infarction, whereas those for LIMK1 and CYP3A4 may be similarly beneficial in assessment of the genetic risk for intracerebral hemorrhage and subarachnoid hemorrhage, respectively. Validation of these findings will require additional studies with independent subject panels.

The aim of the present study was to identify gene polymorphisms that confer susceptibility to obesity. A total of 5448 unrelated Japanese individuals from two independent populations were examined: subject panel A comprised 4252 individuals who visited participating hospitals; subject panel B comprised 1196 community-dwelling elderly individuals. The genotypes for 95 polymorphisms of 67 candidate genes were determined. The chi(2) test revealed that six polymorphisms were related (p<0.05) to the prevalence of obesity in subject panel A; after application of Bonferroni's correction, however, only the 2677G --> A/T polymorphism (rs2032582) of the ATP-binding cassette, subfamily B, member 1 gene (ABCB1) was significantly associated (p=0.0003) with obesity. Subsequent multivariable logistic regression analysis also revealed that the 2677G --> A/T polymorphism of ABCB1 was significantly associated with obesity. For validation of this association, the 2677G --> A/T polymorphism of ABCB1 was examined in subject panel B and again found to be significantly associated with obesity. Body mass index was significantly (p=0.01) greater for individuals with the variant T allele of this polymorphism than for those with the GG genotype in the combined subject panels A and B. Our results suggest that the ABCB1 genotype may prove informative for assessment of genetic risk for obesity in Japanese individuals.

Metabolic syndrome is a risk factor for cardiovascular disease. The aim of the present study was to identify genetic variants that confer susceptibility to atherothrombotic cerebral infarction among individuals with metabolic syndrome in order to allow prediction of genetic risk for this condition. The study population comprised 1284 unrelated Japanese individuals with metabolic syndrome, including 313 subjects with atherothrombotic cerebral infarction and 971 controls. The genotypes for 296 polymorphisms of 202 candidate genes were determined with a method that combines the polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. The Chi-square test, multivariable logistic regression analysis with adjustment for age, sex, body mass index, and the prevalence of hypertension, hypercholesterolemia, and diabetes mellitus, as well as a stepwise forward selection procedure revealed that the 2445G-->A (Ala54Thr) polymorphism (rs1799883) of FABP2, the -108/3G-->4G polymorphism of IPF1 (S82168), the A-->G (Thr94Ala) polymorphism (rs2241883) of FABP1, the G-->A (Asp2213Asn) polymorphism (rs529038) of ROS1, the -11377C-->G polymorphism (rs266729) of ADIPOQ, the 162A-->C polymorphism (rs4769055) of ALOX5AP, the -786T-->C polymorphism (rs2070744) of NOS3, and the 3279C-->T polymorphism (rs7291467) of LGALS2 were associated (P<0.05) with the prevalence of atherothrombotic cerebral infarction. Among these polymorphisms, the 2445G-->A (Ala54Thr) polymorphism of FABP2 was most significantly associated with this condition. Our results suggest that FABP2, IPF1, FABP1, ROS1, ADIPOQ, ALOX5AP, NOS3, and LGALS2 are susceptibility loci for atherothrombotic cerebral infarction among Japanese individuals with metabolic syndrome. Genotypes for these polymorphisms, especially for the 2445G-->A (Ala54Thr) polymorphism of FABP2, may prove informative for the prediction of genetic risk for atherothrombotic cerebral infarction among such individuals.

Although various environmental factors, such as a high-salt diet, a smoking habit, excessive alcohol intake, and physical inactivity, influence the development of hypertension, genetic variation also contributes to an individual's susceptibility to this condition. The purpose of the present study was to identify gene polymorphisms that confer susceptibility or resistance to hypertension, and thereby contribute to the prediction of the genetic risk for this condition. The study population comprised 2752 unrelated Japanese individuals (1370 men, 1382 women), including 1276 subjects with hypertension (774 men, 502 women) and 1476 controls (596 men, 880 women). The genotypes for 50 polymorphisms of 35 candidate genes were determined by a method that combines polymerase chain reaction and sequence-specific oligonucleotide probes with suspension array technology. Evaluation of genotype distributions by the Chi-square test and subsequent multivariable logistic regression analysis with adjustment for age, sex, body mass index, smoking status, and the prevalence of diabetes mellitus and hypercholesterolemia revealed that the -14C-->T polymorphism of ABCA1, the C-->G (Ser2229Cys) polymorphism of ROS1, the C-->T (Asn591Asn) polymorphism of LDLR, the 13989A-->G (Ile118Val) polymorphism of CYP3A4, the C-->G and A-->C polymorphisms of ADIPOR1, and the -519A-->G polymorphism of MMP1 were significantly (P<0.05) associated with the prevalence of hypertension. Systolic and diastolic blood pressure differed significantly among genotypes for the -14C-->T polymorphism of ABCA1 and the C-->G (Ser2229Cys) polymorphism of ROS1, with the variant T and G alleles, respectively, being related to increased blood pressure. These results suggest that polymorphisms of ABCA1 and ROS1 are determinants of blood pressure and the development of hypertension in Japanese individuals. Determination of genotypes for ABCA1 and ROS1 may thus prove informative for the prediction of the genetic risk for hypertension.

Previous experiments indicated that 1-bromopropane (1-BP), an alternative to chloroflurocarbons, is neurotoxic and inhibits spermiation in the testis. Here we investigated the reversibility of the toxic effects of 1-BP in rats. Male Wistar rats were divided into three equal groups of 24 each and exposed by inhalation to 0, 400 or 1000 ppm of 1-BP for 6 weeks (8 hrs/day, 7 days/week). Eight rats from each group were sacrificed at the end of 6 weeks exposure, and at 4 and 14 weeks after the end of exposure, to assess the recovery processes. We studied sperm count, motility, morphology and testicular histopathology, as well as blood pressure, skin temperature and hindlimb muscle strength. At the end of 6 weeks of exposure to 1000 ppm (0 week recovery), testicular weight, epididymal weight, sperm count and motility were low, morphologically abnormal sperm were increased and spermatogenic cells showed diffuse degeneration. These changes did not show full recovery at 14 weeks recovery, with the exception of the prostate and seminal vesicular weights, which recovered back to control values. At 400 ppm, increased retained spermatids at 0 week recovery returned to normal at 4 weeks recovery. Exposure to 1000 ppm produced sustained reduction of hindlimb muscle strength at 14 weeks recovery, whereas normalization of the skin temperature and blood pressure was noted after transient changes. Our study showed that the effect of 1-BP on spermatogenesis is dose-dependent; low exposure inhibited spermiation and hormone-dependent organ weight reduction and these changes were transient, while a higher dose of 1000 ppm 1-BP caused persistent depletion of spermatogenic cells.

The purpose of the present study was to identify genetic variants that confer susceptibility to dyslipidemia. A total of 5213 individuals from two independent populations were examined: Subject panel A comprised 3794 individuals who visited participating hospitals; subject panel B comprised 1419 community-dwelling elderly individuals. The genotypes for 100 polymorphisms of 65 candidate genes were determined. The chi(2) test and multivariable logistic regression analysis revealed that seven polymorphisms of APOA5, APOC3, APOA1, ACAT2, and LPL were significantly associated with hypertriglyceridemia, six polymorphisms of APOA5, LIPC, and CYP3A4 with low HDL-cholesterol, and three polymorphisms of APOE and CCR2 with high LDL-cholesterol in subject panel A. For validation of these associations, the same polymorphisms were examined in subject panel B. Six polymorphisms of APOA5, APOC3, APOA1, and LPL were again significantly associated with hypertriglyceridemia, three polymorphisms of APOA5 with low HDL-cholesterol, and two polymorphisms of APOE with high LDL-cholesterol. Serum triglyceride, HDL-cholesterol, and LDL-cholesterol concentrations differed significantly among genotypes of these corresponding polymorphisms in both subject panels. These results indicate that polymorphisms of APOA5, APOC3, APOA1, and LPL are determinants of hypertriglyceridemia and that those of APOA5 and APOE are determinants of low HDL-cholesterol and high LDL-cholesterol, respectively, in Japanese individuals.

Sepsis is characterized by various symptoms, signs and underlying pathophysiology. To investigate possible mechanisms underlying this diversity, we compared the cardiovascular effects of lipopolysaccharide (LPS) derived from Escherichia coli (E-LPS) with those of LPS from Pseudomonas aeruginosa (P-LPS) in rats. We also examined the possible roles of tumor necrosis factor-alpha (TNF-alpha) and oxidative stress in LPS-induced cardiovascular damage. E-LPS (10 mg/kg body weight) or P-LPS (2 mg/kg body weight) was administered intravenously to Wistar rats. Echocardiography was serially performed. E-LPS induced an increase in left ventricular fractional shortening that persisted for at least 6 h, whereas P-LPS elicited an initial increase and a subsequent decrease in this parameter. Histological analysis revealed that P-LPS induced interstitial edema, congestion, intramyocardial bleeding, myocardial necrosis, infiltration of inflammatory cells, and formation of fibrin thrombi in the heart, whereas no pathological changes were apparent in the hearts of rats treated with E-LPS. Furthermore, the plasma concentration of TNF-alpha in rats treated with P-LPS was greater than that in rats treated with E-LPS, but the glutathione redox ratio in the heart was not affected by either type of LPS. In conclusion, E-LPS and P-LPS induced distinct patterns of functional and structural responses in the cardiovascular systems of rats. These differential responses may be attributable in part to the difference in the associated increases in the plasma concentration of TNF-alpha. The cardiovascular effects of LPS thus depend on the causative organisms.

Cardiotoxicity is a treatment-limiting side effect of the anticancer drug doxorubicin (DOX). We have now investigated the roles of oxidative stress and signaling by the protein kinase Akt in DOX-induced cardiotoxicity as well as the effects on such toxicity both of fenofibrate, an agonist of peroxisome proliferator-activated receptor-alpha, and of polyethylene glycol-conjugated superoxide dismutase (PEG-SOD), an antioxidant. Mice injected intraperitoneally with DOX were treated for 4 days with fenofibrate or PEG-SOD. Fenofibrate and PEG-SOD each prevented the induction of cardiac dysfunction by DOX. Both drugs also inhibited the activation of the transcription factor NF-kappaB and increase in lipid peroxidation in the left ventricle induced by DOX, whereas only PEG-SOD inhibited the DOX-induced activation of Akt and Akt-regulated gene expression. These results suggest that fenofibrate and PEG-SOD prevented cardiac dysfunction induced by DOX through normalization of oxidative stress and redox-regulated NF-kappaB signaling.

OBJECTIVE: The aryl hydrocarbon receptor (AHR) is a transcription factor that binds to DNA as a heterodimer with the AHR nuclear translocator (ARNT) after interaction with ligands such as polycyclic and halogenated aromatic hydrocarbons found in tobacco smoke and the environment. We have investigated the interaction between AHR and hypoxia signaling pathways in regulation of angiogenesis with the use of a surgical model of ischemia. METHODS AND RESULTS: Ischemia was induced by femoral artery occlusion in wild-type and AHR-null mice. Ischemia-induced angiogenesis was markedly enhanced in AHR-null mice compared with that in wild-type animals. Ischemia-induced upregulation of the expression of hypoxia-inducible factor-1alpha (HIF-1alpha) and ARNT as well as that of target genes for these transcription factors, such as that for vascular endothelial growth factor (VEGF), were also enhanced in AHR-null mice. Furthermore, the DNA binding activity of the HIF-1alpha-ARNT complex as well as the association of HIF-1alpha and ARNT with the VEGF gene promoter were increased by ischemia to a greater extent in AHR-null mice than in wild-type animals. CONCLUSIONS: Ablation of AHR resulted in enhancement of ischemia-induced angiogenesis. This effect was likely attributable in part to the associated enhancement of ischemia-induced VEGF expression, which in turn may be caused by an increased abundance and activity of the HIF-1alpha-ARNT heterodimer.

Oxidative stress is an important susceptibility factor for dilated cardiomyopathy. We have investigated the effects of bisoprolol, a beta1-selective adrenoceptor blocker, on oxidative stress and the development of cardiac dysfunction in a model of dilated cardiomyopathy. Male TO-2 and control hamsters at 8 weeks of age were treated with bisoprolol (5 mg/kg per day) or vehicle for 4 weeks. Treatment with bisoprolol prevented the progression of cardiac dysfunction in TO-2 hamsters. This drug did not affect the increase in NADPH oxidase activity but prevented the reduction in activity and expression of mitochondrial manganese-dependent superoxide dismutase as well as the increases in the concentrations of interleukin-1beta and tumor necrosis factor-alpha in the left ventricle of TO-2 hamsters. Attenuation of the development of cardiac dysfunction by bisoprolol may thus result in part from normalization of the associated increases in the levels of oxidative stress and pro-inflammatory cytokines in the left ventricle.

Peroxisome proliferator-activated receptor-alpha (PPAR-alpha) is a key regulator of lipid and glucose metabolism and is implicated in inflammation. We investigated the effects of the PPAR-alpha activator fenofibrate on, as well as the role of redox-regulated transcription factors, in the development of left ventricular (LV) hypertrophy and heart failure in Dahl salt-sensitive (DS) rats. DS rats were fed a high-salt diet and treated with either fenofibrate (30 or 50 mg/kg per day) or vehicle from 7 weeks of age. Fenofibrate inhibited the development of compensated hypertensive LV hypertrophy, attenuated the LV relaxation abnormality and systolic dysfunction, and improved the survival rate in DS rats. It also prevented a decrease in the ratio of reduced to oxidized glutathione and inhibited up-regulation of the DNA binding activities of the redox-regulated transcription factors NF-kappaB, AP-1, Egr-1, SP1, and Ets-1 induced in the left ventricle by the high-salt diet. Expression of target genes for these transcription factors, including those for adhesion molecules (VCAM-1, ICAM-1), cytokines (MCP-1), growth factors (TGF-beta, PDGF-B), and osteopontin, was also increased by the high-salt diet in a manner sensitive to treatment with fenofibrate. Furthermore, the infiltration of macrophages and T lymphocytes into the left ventricle and the increase in the plasma concentration of C-reactive protein were inhibited by fenofibrate. The PPAR-alpha activator fenofibrate thus attenuated the progression of heart failure and improved the survival rate in this rat model. These effects were associated with inhibition of the inflammatory response and of activation of redox-regulated transcription factors in the left ventricle.

1-Bromopropane (1-BP) exhibits neuroreproductive toxicities in adult rats and humans. Here, we determined the effects of exposure of rat dams to 1-BP during pregnancy and lactation on the growth and sexual maturation of their offspring. In Experiment 1, 40 rats were exposed to 0, 100, 400 and 800ppm 1-BP during pregnancy and lactation for 8h/day. Ten rats that were not placed in chambers throughout the experiment served to observe the effect of separation of dams from offspring. In Experiment 2, three groups of 10 pregnant rats each were exposed to fresh air in three chambers and 10 other rats were exposed to 800ppm 1-BP during pregnancy and lactation for 8h/day. After delivery, offspring of the exposed and non-exposed dams were swapped so that they were nursed by the opposite dams. In Experiment 1, the survival rate and body weight of offspring were lower than the non-exposed in 1-BP dose-dependent manner. In Experiment 2, the survival rate and body weight of offspring (Group A) nursed by exposed dams and those (Group B) of exposed dams were significantly lower than non-exposed groups. The body weight of Group A was lower than that of Group B, although the two groups showed a significant equal decrease in the survival rate. The number of dead offspring from Group A was significantly higher. Our results indicate that exposure to 1-BP during pregnancy and lactation has comparable effects on survival rate, but exposure during lactation has a more adverse effect on growth of offspring than that during pregnancy. Moreover, exposure during lactation is associated with reduced early survival of third generation (F2) rats.

Chronic elevation of plasma aldosterone contributes to heart failure. Mineralocorticoid receptor (MR) antagonism is cardioprotective in such a setting, but whether such protection occurs in the presence of low-aldosteroneconcentrations remains unclear. Weinvestigated whether MR blockade attenuates cardiac hypertrophy and failure in rats with salt-sensitive hypertension. Dahl salt-sensitive (DS) rats fed a high-salt diet from 7 weeks develop concentric left ventricular (LV) hypertrophy secondary to hypertension at 12 weeks followed by heart failure at 19 weeks (DS-CHF). DS rats on such a diet were treated with a non-antihypertensive dose of the selective MR antagonist eplerenone from 12 to 19 weeks. Renin activity and aldosterone concentration in plasma were decreased in DS-CHF rats compared with controls. LV hypertrophy and fibrosis, as well as macrophage infiltration around coronary vessels, were apparent in DS-CHF rats. The amounts of mRNAs for 11beta-hydroxysteroid dehydrogenase type 1, MR, monocyte chemoattractant protein 1, and osteopontin were increased in these hearts. Treatment of DS-CHF rats with eplerenone inhibited these changes in gene expression, as well as coronary va

OBJECTIVES: Oxidative stress is implicated in the pathogenesis of heart failure and affects the activity of matrix metalloproteinases (MMPs). We have now investigated the role of MMPs and their tissue inhibitors (TIMPs) in the transition from compensated left ventricular (LV) hypertrophy to heart failure as well as the effects of pravastatin on this transition in a rat model. METHODS: Dahl salt-sensitive rats were fed a high-salt (8% NaCl) diet and treated with pravastatin (50 or 100 mg/kg per day) or vehicle from 7 weeks of age. RESULTS: Pravastatin did not attenuate LV hypertrophy apparent at 12 or 18 weeks of age. However, the high dose of this drug markedly improved indices of diastolic function (early diastolic myocardial velocity) and systolic function (LV fractional shortening) at 18 weeks of age and increased the survival rate. It also prevented a decrease in the ratio of reduced to oxidized glutathione and an increase in NADPH oxidase activity in the left ventricle induced by the high-salt diet. The activities of MMP2 and MMP9 and the abundance of TIMP1 and TIMP2 in LV tissue were increased at 18 weeks of age, and pravastatin also prevented these changes. CONCLUSION: Although pravastatin did not attenuate LV hypertrophy, it prevented the transition from compensated hypertrophy to heart failure in this rat model. This effect of pravastatin may result from a reduction both in the level of oxidative stress and in MMP activity in the heart.

Mineralocorticoid receptor antagonism reduces mortality associated with heart failure by mechanisms that remain unclear. The effects of the mineralocorticoid receptor antagonist spironolactone on left ventricular (LV) function and chamber stiffness associated with myocardial fibrosis were investigated in mildly symptomatic patients with idiopathic dilated cardiomyopathy (DCM).

Long-term administration of vasodilators increases shear stress, which is thought to be important for vascular growth in the heart. Nicorandil, an activator of ATP-sensitive potassium channels with a nitrate-like action, is a potent vasodilator. We have now investigated the effects of nicorandil on vascular growth and gene expression in the failing heart of Dahl salt-sensitive (DS) hypertensive rats. DS rats fed a high-salt diet from 6 weeks of age develop concentric cardiac hypertrophy secondary to hypertension at 11 weeks, followed by heart failure at 18 weeks. DS rats on such a diet were treated with a nonantihypertensive oral dose of nicorandil (6 mg/kg per day) or vehicle from 11 to 18 weeks of age. Treatment of DS rats with nicorandil improved cardiac function and attenuated the development of heart failure. Myocardial capillary and arteriolar densities did not differ between vehicle-treated DS rats and age-matched controls. The abundance of mRNAs for endothelial NO synthase (eNOS), vascular endothelial growth factor (VEGF), the VEGF receptor Flt-1, and basic fibroblast growth factor (bFGF) in the myocardium was markedly reduced in vehicle-treated DS rats compared with contro