Cross-Sectional Inverse Association of Regular Soy Intake with Insulin Resistance in Japanese Elderly

Levels of isoflavones, biomarkers of soy intake, in 24-hour urine (24U) were inversely related to coronary heart disease (CHD) mortality in the World Health Organization's Cardiovascular Disease and Alimentary Comparison Study. Considering 24 U isoflavone levels were highest and CHD mortality was lowest in the Japanese, who maintained the world's longest life expectancy, the association of regular soy intake with cardiometabolic risk was investigated in Japanese adults (20-49 years old) and elderly (50-79 years old). In multivariate analysis adjusted for age, sex, and drug treatments, mean 24 U isoflavone excretion was significantly inversely associated with insulin resistance in the elderly and significantly associated with blood folate and potassium in the elderly, but also positively associated with 24 U salt in the elderly. These findings indicate that low-salt soy should be recommended to improve glucose metabolism in elderly Japanese.

Association of genetic variants for susceptibility to obesity with type 2 diabetes in Japanese individuals

AIMS/HYPOTHESIS

In populations of East Asian descent, we performed a replication study of loci previously identified in populations of European descent as being associated with obesity measures such as BMI and type 2 diabetes.

METHODS

We genotyped 14 single nucleotide polymorphisms (SNPs) from 13 candidate loci that had previously been identified by genome-wide association meta-analyses for obesity measures in Europeans. Genotyping was done in 18,264 participants from two general Japanese populations. For SNPs showing an obesity association in Japanese individuals, we further examined diabetes associations in up to 6,781 cases and 7,307 controls from a subset of the original, as well as from additional populations.

RESULTS

Significant obesity associations (p < 0.1 two-tailed, concordant direction with previous reports) were replicated for 11 SNPs from the following ten loci in Japanese participants: SEC16B, TMEM18, GNPDA2, BDNF, MTCH2, BCDIN3D-FAIM2, SH2B1-ATP2A1, FTO, MC4R and KCTD15. The strongest effect was observed at TMEM18 rs4854344 (p = 7.1 × 10(-7) for BMI). Among the 11 SNPs showing significant obesity association, six were also associated with diabetes (OR 1.05-1.17; p = 0.04-2.4 × 10(-7)) after adjustment for BMI in the Japanese. When meta-analysed with data from the previous reports, the BMI-adjusted diabetes association was found to be highly significant for the FTO locus in East Asians (OR 1.13; 95% CI 1.09-1.18; p = 7.8 × 10(-10)) with substantial inter-ethnic heterogeneity (p = 0.003).

CONCLUSIONS/INTERPRETATION

We confirmed that ten candidate loci are associated with obesity measures in the general Japanese populations. Six (of ten) loci exert diabetogenic effects in the Japanese, although relatively modest in size, and independently of increased adiposity.

Neuronal vulnerability of stroke-prone spontaneously hypertensive rats to ischemia and its prevention with antioxidants such as vitamin E

Stroke-prone spontaneously hypertensive rats (SHRSP/Izm) develop severe hypertension, and more than 95% of them die of cerebral stroke. Hypoxic stimulation followed by oxygen reperfusion induces neuronal damage in both normotensive Wistar Kyoto/Izm (WKY/Izm) and SHRSP/Izm rats, and the percentage of neurons that undergo apoptosis during hypoxia-reperfusion is markedly higher in SHRSP/Izm rats than in WKY/Izm rats. The biochemical characteristics of the SHRSP/Izm rats, unlike those of WKY/Izm rats, might act as a factor in the stroke proneness of SHRSP/Izm rats. In the hippocampus, the formation of hydroxyl radicals and the cerebral blood flow-independent formation of nitric oxide (NO) were strongly increased after reperfusion in SHRSP/Izm rats, and the neuronal expression of the thioredoxin and Bcl-2 genes was significantly decreased in the SHRSP/Izm rats compared with the WKY/Izm rats. On the other hand, the effects of antioxidants against neuronal death associated with cerebral ischemia-reperfusion were stronger in the SHRSP/Izm rats, in which the addition of vitamin E or ebselen almost completely inhibited neuronal death. Namely, the addition of 100 microg/ml of vitamin E under hypoxia/reoxygenation (H/R) conditions completely inhibited WKY and SHRSP/Izm neuronal death. Vitamin E exerts a marked inhibitory effect against neuronal damage via its incorporation into mitochondrial membranes, where it captures reactive oxygen and free radicals. The susceptibility of neurons to apoptosis in SHRSP/Izm rats is partly due to an insufficiency of mitochondrial redox regulation and apoptosis-inhibitory proteins. In this review, we describe the neuronal vulnerability of SHRSP/Izm rats induced by cerebral ischemia and the effects of antioxidants such as vitamin E.

Common variants at the GCK, GCKR, G6PC2-ABCB11 and MTNR1B loci are associated with fasting glucose in two Asian populations

AIMS/HYPOTHESIS

To test fasting glucose association at four loci recently identified or verified by genome-wide association (GWA) studies of European populations, we performed a replication study in two Asian populations.

METHODS

We genotyped five common variants previously reported in Europeans: rs1799884 (GCK), rs780094 (GCKR), rs560887 (G6PC2-ABCB11) and both rs1387153 and rs10830963 (MTNR1B) in the general Japanese (n = 4,813) and Sri Lankan (n = 2,319) populations. To identify novel variants, we further examined genetic associations near each locus by using GWA scan data on 776 non-diabetic Japanese samples.

RESULTS

Fasting glucose association was replicated for the five single nucleotide polymorphisms (SNPs) at p < 0.05 (one-tailed test) in South Asians (Sri Lankan) as well as in East Asians (Japanese). In fine-mapping by GWA scan data, we identified in the G6PC2-ABCB11 region a novel SNP, rs3755157, with significant association in Japanese (p = 2.6 x 10(-8)) and Sri Lankan (p = 0.001) populations. The strength of association was more prominent at rs3755157 than that of the original SNP rs560887, with allelic heterogeneity detected between the SNPs. On analysing the cumulative effect of associated SNPs, we found the per-allele gradients (beta = 0.055 and 0.069 mmol/l in Japanese and Sri Lankans, respectively) to be almost equivalent to those reported in Europeans.

CONCLUSIONS/INTERPRETATION

Fasting glucose association at four tested loci was proven to be replicable across ethnic groups. Despite this overall consistency, ethnic diversity in the pattern and strength of linkage disequilibrium certainly exists and can help to appreciably reduce potential causal variants after GWA studies.

Pontine hypoplasia in children with periventricular leukomalacia

BACKGROUND AND PURPOSE

The brain stem in patients with periventricular leukomalacia (PVL) appears smaller than normal on MR imaging, but few reports have described this feature, and the number of patients has been relatively small. The present study was conducted to examine the hypothesis that the pons in patients with PVL is smaller than normal.

MATERIALS AND METHODS

Using MR imaging, we examined 80 children (43 boys and 37 girls) with PVL and 80 age-matched control children (41 boys and 39 girls). The control children were diagnosed as neurologically and developmentally normal by pediatric neurologists and also showed normal MR imaging findings. MR imaging was performed at a corrected age range of 0-5 years in both groups. We measured the anteroposterior diameter of the whole pons, the tegmentum and the basis, and the corpus callosal length by using midline T1-weighted sagittal images and compared each parameter between the PVL groups and the control groups.

RESULTS

Pontine diameters in all of the regions were significantly smaller in the PVL group than in the control group (mean +/- SD, whole pontine diameters, 1.66 +/- 0.21 and 1.87 +/- 0.23 cm [P < .001]; basis diameters, 0.42 +/- 0.10 and 0.51 +/- 0.14 [P < .001]; tegmentum diameters, 1.23 +/- 0.20 and 1.36 +/- 0.19 [P < .001], respectively). The respective corpus callosal lengths were 5.02 +/- 0.90 and 5.51 +/- 0.76 (P < .001). There was no significant difference in the basis/tegmentum ratio between the PVL group and the control group. When the age-related pontine diameter differences were examined, there was already a significant difference at 0 years of age between the 2 groups. There was a significant correlation between whole pontine diameter and corpus callosal length in the PVL group (correlation coefficient, 0.52; P < .001) and the control group (correlation coefficient, 0.63; P < .001).

CONCLUSION

We have proven that pontine diameter in patients with PVL is significantly smaller than that in normal control subjects, including each diameter of basis and tegmentum.

Dietary habits, plasma polyunsaturated fatty acids and selected coronary disease risk factors in Tanzania

OBJECTIVES

To compare dietary habits and percent compositions of omega (omega)-3 fatty acid (FA) in plasma phospholipids and to examine if there is any association between fish intake and selected coronary disease risk (CHD) factors in this population.

DESIGN

Cross sectional population study.

SETTING

Three areas in Tanzania: urban Dar es Salaam (D), rural Handeni (H) and pastoralist population of Maasai in Moduli (Mo).

SUBJECTS

One hundred and five participants (Dar 36, Handeni 37 and Monduli 32) aged 47-57 years.

MAIN OUTCOME MEASURES

Fatty acids composition in plasma phospholipids.

RESULTS

The frequency of intake of fish, meat, coconut milk and fruits was higher in Dar than in Handeni or Monduli (all p< 0.0001). The Maasai from Monduli had the highest percentage consumption of milk in a week (p<0.0001) and lowest intake of fish (p<0.0001). Participants from Handeni had the highest prevalence of consumption of green vegetables (p<0.0001). Percent compositions of arachidonic acid (AA; C20: 4omega-6) and docosahexaenoic acid (DHA; C22: 6omega-3) in plasma phospholipids were the lowest in Monduli (p<0.0001). Selected coronary disease risk factors were higher in the urban area Dar. The frequency of intake of fish per week correlated negatively with total cholesterol (TC) and LDL-C and HBA1c percent but not with blood pressure. The percent composition of omega-3 FA in plasma phospholipids was positively correlated with the frequency of intake of fish a week.

CONCLUSION

Our results indicate that, there are significant differences in dietary patterns among the three study areas, and that the intake of fish is inversely associated with selected risk factors for coronary heart disease.

Can foods with added soya-protein or fish-oil reduce risk factors for coronary disease? A factorial randomised controlled trial

BACKGROUND AND AIMS

To develop functional foods which are capable of reducing key risk factors for coronary heart disease in an at risk population. The specific hypothesis tested here was that providing bread, cracker biscuits and snack bars fortified with DHA (long-chain omega 3) and soya-protein would havd a positive impact on cholesterol and blood pressure.

METHODS AND RESULTS

A pragmatic, double-blind, factorial placebo-controlled randomised trial recruiting 213 middle-aged men and women with untreated elevated total cholesterol or blood pressure. The factors examined were the effect of giving supplies of bread, cereal bars and cracker biscuits fortified with 2 g fish oils (DHA, 22: 6n-3), or 25 g soya-protein (containing 50 mg of isoflavonoids) for five weeks. Primary and secondary outcomes included total, low-density and high-density cholesterol (HDL-C), and systolic and diastolic blood pressure. Compliance was assessed using biomarkers and food intake histories. DHA enriched foods increased HDL-C by 6.0% (95% CI 2.5%, 9.6%) but had no effect on total or low-density cholesterol or blood pressure. Overall, soya-protein did not influence any of the outcomes assessed. However, in women only, soya-protein increased systolic blood pressure by 5.9% (95% CI 1.73, 9.9%).

CONCLUSIONS

Adding DHA (fish-oils) to staple foods might supplement existing methods to help reduce CVD morbidity and mortality. However, these findings highlight the importance of ensuring that functional foods do not present any harms to particular subgroups within a general population, if they are to be made freely available to consumers. This latter point requires further attention by the research community in relation to soya-protein.

Polyunsaturated fatty acids induce tight junctions to form in brain capillary endothelial cells

Tight junctions create a rate-limiting barrier to the diffusion of solutes between vertebrate epithelial cells and endothelial cells. They are also controlled within individual cells by a variety of physiologically relevant signals. We investigated the effects of polyunsaturated fatty acids on the formation of tight junctions in brain capillary endothelial cells, monitoring the transepithelial electrical resistance, and analyzed the expression of occludin messenger RNA. Brain-capillary endothelial cells were grown to confluence on filters and exposed to eicosapentaenoic acids, gamma linolenic acid and linoleic acid. Transepithelial electrical resistance was determined with voltage-measuring electrodes. The messenger RNA expression of occludin was quantitated by real-time quantitative reverse transcriptase-polymerase chain reaction. The basal resistance across monolayers of porcine brain capillary endothelial cells was 83+/-8.1 Omega cm(2). Cells cultured in eicosapentaenoic acids and gamma linolenic acid, but not linolenic acid, displayed a 2.7-fold increase in transepithelial electrical resistance at 10 microM in brain capillary endothelial cells. The expression level of occludin messenger RNA increased markedly immediately after the exposure to eicosapentaenoic acids or gamma linolenic acid. Following an 8 h exposure to exogenous eicosapentaenoic acids or gamma linolenic acid, occludin messenger RNA levels were significantly increased. In addition, the rise in transepithelial electrical resistance induced by eicosapentaenoic acids and gamma linolenic acid was markedly inhibited by the tyrosine kinase inhibitors genistein and PP2 and protein kinase C inhibitor, calphostin C. In contrast, the rise in transepithelial electrical resistance induced by eicosapentaenoic acids and gamma linolenic acid was not inhibited by the PI 3-kinase inhibitor, LY294002. We conclude that eicosapentaenoic acids and gamma linolenic acid increased the transepithelial electrical resistance and the expression of occludin messenger RNA in brain capillary endothelial cells. This gamma linolenic acid and eicosapentaenoic acid induced assembly of tight junction is likely to be regulated by protein kinase C and tyrosine kinase activity.

Determinants of hyperleptinaemia in an African population

OBJECTIVE

To examine the determinants for elevated plasma leptin concentration in normal weight (NW), obese (OB), and morbidly obese (MO) individuals in Tanzania.

DESIGN

Cross-sectional epidemiological study, the CARDIAC study.

SETTING

Three areas in Tanzania; Dar es Salaam, urban (U), Handeni, rural (R) and Monduli, pastoralists (P), in August 1998.

SUBJECTS

Five hundred and forty five participants from a random sample of 600 people aged 46-58 years.

MAIN OUTCOME MEASURES

Plasma leptin concentrations, height, weight, body mass index (BMI), lipid profiles, haemoglobin A1c (HBA1c), and blood pressure (BP).

RESULTS

Plasma leptin concentrations were higher in women than in men (women; 16.0 ng/mL, men; 3.1 ng/mL; p<0.0001). Women showed a higher mean body mass index (BMI), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) than men. In both genders, plasma leptin concentration, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), systolic BP (SBP) and diastolic BP (DBP) were significantly higher in OB than in NW participants. MO women had significantly higher leptin concentration, SBP and DBP compared with the other two groups. In NW men, log leptin concentrations showed a direct correlation with weight, BMI, HBA1c, TC, LDL-C, TG, SBP and DBP (all p<0.0001 except TG; p<0.001), while among NW women and OB men, weight and BMI correlated positively with log leptin (all p<0.05). OB women observed a positive correlation between log leptin and weight, BMI and LDL-C. Regression analysis indicated that among NW subjects, gender, BMI and TC explained 53.9% of the variation in log leptin. In OB subjects, gender, BMI and LDL-C explained 51.7% of the variability in leptin levels. No relationship was found between log leptin and CVD risk factors among MO subjects.

CONCLUSION

The most important determinants for hyperleptinaemia in NW participants were gender, BMI, TC, while in addition to these LDL-C, was an important determinant of leptin concentration in OB individuals. In MO women, the high leptin concentrations did not reflect the amount of adipose stores.

Okinawa: an exception to the social gradient of life expectancy in Japan

This paper examines why the social gradient of life expectancy does not apply in Japan when Okinawa is considered. The social gradient thesis links differences in longevity to social rank, with people and populations in higher status hierarchical positions having lower mortality and longer life expectancies than those beneath them in the social scale. Japan has been cited as a major example of this thesis in that Japanese life expectancy improved dramatically as Japan rose to the top echelon of nations in economic rank in the late 20th century. Thus it follows that Japan's most affluent and leading prefectures should be the major catalysts behind the nation's rise in life expectancy as well to the number one position in the world. However, this is not the case as life expectancy in Okinawa, Japan's poorest prefecture, exceeds that of Japan as a whole. We find that the social gradient of life expectancy does not apply at the prefectural level and question its validity for geographical areas. We suggest that healthy lifestyles, especially diet and the social support of family and friends, are more important than sense of hierarchy for longevity in Okinawa.

Implications from and for food cultures for cardiovascular diseases: Japanese food, particularly Okinawan diets

Okinawans, who have a different ethnicity and food cultural history to other Japanese nationals, and an exceptional longevity have been studied at home and as migrant groups in Hawaii and Brazil. Biomarkers for fish and soy intake and intervention studies indicate that these foods, along with seaweed and green vegetables are candidates for chronic non-communicable disease prevention.

Obesity and lipid profiles in middle aged men and women in Tanzania

OBJECTIVE

To examine the relationship between obesity and lipid profiles and to compare the effects of total obesity and central adiposity on lipids in three locations in Tanzania.

DESIGN

Cross-sectional epidemiological study.

SETTING

Three areas in Tanzania: Dar es Salaam (urban), Handeni (rural) and Monduli (pastoralists), in August 1998.

SUBJECTS

Five hundred and forty five men and women from a random sample of 600 people aged 46-58 years.

MAIN OUTCOME MEASURES

Mean BMI, waist circumference, WHR, TC, HDL-C, LDL-C, TG and LDL/HDL ratio. Prevalence rates of overweight,obesity, central obesity and dyslipidaemia.

RESULTS

As compared to men, women had higher BMI (24.7 versus 22.5 kg/m2, p<0.0001), waist circumference (92.4 versus 89.1 cm, p<0.05), TC (4.9 versus 4.2 mmol/L, p<0.0001) and LDL-C (3.3 versus 2.6 mmol/L, p<0.0001). The urban population demonstrated higher levels of lipid factors than the rural population (TC, men 4.8 mmol/L; women 5.3 mmol/L, p<0.0001; TG, men 3.6 mmol/L; women 3.7 mmol/L, p<0.0001, LDL-C, men 2.8 mmol/L, p<0.0001). BMI and waist circumference correlated positively with serum TC, TG, and LDL-C in both genders. Stepwise regression analysis showed that BMI predicted triglyceride concentration in men (p<0.05) and women (p<0.0001). Waist circumference predicted levels of TC in women only (p<0.0001) and of LDL-C in both genders (men p<0.05, women p<0.0001). The prevalence of overweight, obesity and central obesity were significantly higher in urban than in rural areas in both men and women. Compared to lean subjects, obese men and women had significantly higher mean serum TC, TG, LDL-C and a higher prevalence of dyslipidaemia. The mean levels of TC, TG and LDL cholesterol increased across successive increases in BMI and waist circumference quintiles in both genders.

CONCLUSION

Subjects from the urban area had greater lipid abnormalities related to obesity than those from the rural area and that, central adiposity had a greater effect on total cholesterol and LDL cholesterol among women than was BMI.

Antihypertensive effects of acetic acid and vinegar on spontaneously hypertensive rats

To clarify the possibility of a preventive effect of dietary vinegar on blood pressure, long-term administration of vinegar or the acetic acid to SHR was examined. As a result, it was observed that acetic acid itself, the main component of vinegar, significantly reduced both blood pressure (p<0.05) and renin activity (p<0.01) compared to controls given no acetic acid or vinegar, as well as vinegar. There were no significant differences in angiotensin I-converting enzyme activity in various organs. As for the mechanism of this function, it was suggested that this reduction in blood pressure may be caused by the significant reduction in renin activity and the subsequent decrease in angiotensin II. From this study, it was also suggested that the antihypertensive effect of vinegar is mainly due to the acetic acid in it.

Difference in subcellular distribution between 45- and 37-kDa mevalonate pyrophosphate decarboxylase in rat liver

We previously reported that the CP diet (a diet containing 5% cholestyramine and 0.1% pravastatin)-induced new species of 37-kDa mevalonate pyrophosphate decarboxylase (MPD) was characteristically and immunologically very similar to the well-known 45-kDa MPD. In the present study, we found a difference in subcellular distribution between 45- and 37-kDa MPD by cell fractionation and immunoblot analysis. The cytosol fraction contained 45- and 37-kDa MPD. Peroxisomal fraction contained a small amount of 45-kDa MPD, but not 37-kDa MPD. Also, 45-kDa MPD in peroxisome is localized in the matrix. From these data, the difference in subcellular distribution between 45- and 37-kDa MPD may be due to differences in the physiological role of cholesterol biosynthesis in rat liver.

Mevalonate pyrophosphate decarboxylase in stroke-prone spontaneously hypertensive rat is reduced from the age of two weeks

We carried out a comparison of tissue distribution of mevalonate pyrophosphate decarboxylase (MPD) between normotensive Wistar Kyoto rat (WKY) and stroke-prone spontaneously hypertensive rat (SHRSP) using Western blotting. However, there was no difference in tissue distribution of MPD between WKY and SHRSP, expect in brain and liver. We then compared the MPD between WKY and SHRSP liver at several weeks of age. We found that MPD in the liver as well as brain of SHRSP was significantly reduced from two weeks of age. This data is useful to identify or understand the mechanism underlying the reduced amount of MPD in SHRSP.

Mevalonate pyrophosphate decarboxylase is predominantly located in the cytosol of rat hepatocytes

Mevalonate pyrophosphate decarboxylase (MPD) is found in the 100000 x g supernatant fraction of cells or tissues and is considered to be a cytosolic protein. Recently, other groups reported that MPD is mostly located in the peroxisomes. In this study, we used two different methods to determine whether MPD is predominantly located in the peroxisomes or the cytosol of rat hepatocytes. 1) In permeabilized rat hepatocytes or normal rat kidney cells treated with digitonin, which lack cytosolic enzyme, MPD was mainly present in the medium. 2) Double immunofluorescent labeling of cells with both anti-MPD antibody and anti-hexokinase antibody yielded an immunofluorescent pattern for both enzymes typical of the cytosolic protein. These results indicate that MPD is predominantly located in the cytosol of rat hepatocytes.

Effects of vitamin E and sesamin on hypertension and cerebral thrombogenesis in stroke-prone spontaneously hypertensive rats

The preventive effects of sesamin, a lignan from sesame oil, and vitamin E on hypertension and thrombosis were examined using stroke-prone spontaneously hypertensive rats (SHRSP). At 5 weeks of age the animals were separated into four groups: (i) a control group; (ii) a vitamin E group, which was given a 1,000 mg alpha-tocopherol/kg diet; (iii) a sesamin group, given a 1,000 mg sesamin/kg diet; and (iv) a vitamin E plus sesamin group, given a 1,000 mg alpha-tocopherol plus 1,000 mg sesamin/kg diet for 5 weeks from 5 to 10 weeks of age. Resting blood pressure was measured by the tail-cuff method once weekly. A closed cranial window was created and platelet-rich thrombi were induced in vivo using a helium-neon laser technique. The number of laser pulses required for formation of an occlusive thrombus was used as an index of thrombotic tendency. In control rats, systolic blood pressure and the amount of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) became significantly elevated with age. However, the elevation in blood pressure and 8-OHdG were significantly suppressed in rats administrated vitamin E, sesamin, or vitamin E plus sesamin. At 10 weeks, the number of laser pulses required to induce an occlusive thrombus in arterioles of the control group was significantly lower than in the other groups (p<0.05). These results indicate that chronic ingestion of vitamin E and sesamin attenuated each of elevation in blood pressure, oxidative stress and thrombotic tendency, suggesting that these treatments might be beneficial in the prevention of hypertension and stroke.

Tissue distribution of a major mevalonate pyrophosphate decarboxylase in rats

The 45- and 35-kDa subunits of mevalonate pyrophosphate decarboxylase (MPD) have been purified from rat liver. In this study, we examined the relationship between 45- and 35-kDa MPD and the tissue distribution of a major MPD in rat liver. When the crude extract of rat liver fed on normal chow was subjected to immunoblot analysis using anti-rat 45-kDa MPD antibody, only the 45-kDa band was detected. In a pulse-chase experiment using anti-rat 45-kDa MPD antibody, there was no precursor-product relationship between the 45- and the 35-kDa MPD. In immunoprecipitation, more than 85% of MPD activity in the rat liver was depleted from the crude extract with an excess of the above antibody. When 45-kDa MPD contents in tissues were analyzed by immunoblotting, a single protein band with an apparent molecular weight of 45 kDa was detected in all tissues. The specific protein content of 45-kDa MPD in liver was markedly higher than in other tissues. The activity/amount ratio varied among brain, liver, and testis, being significantly highest in the liver. From these data, it is suggested that 45-kDa MPD serves as a major enzyme involved in cholesterol biosynthesis in rat liver and that a tissue-specific regulator or isozyme of 45-kDa MPD is present in rat liver.

Up-regulation of uncoupling protein 3 gene expression by fatty acids and agonists for PPARs in L6 myotubes

Uncoupling protein 3 (UCP3), which uncouples electron transport from ATP synthesis, is expressed at high levels in the skeletal muscle, an important organ in glucose and lipid metabolism. Because several reports proposed that fatty acids induced UCP3 gene expression in skeletal muscle in vivo, in the present study we examined the regulation of UCP3 gene expression by various fatty acids using L6 myotubes. UCP3 gene expression was increased in L6 myotubes by various fatty acids or by alpha-bromopalmitate, a nonmetabolized derivative of palmitic acid. Because fatty acids are also known as agonists for PPARs, we examined the involvement of PPARs in the regulation of the UCP3 gene expression. L-165041, a PPAR delta agonist, increased UCP3 gene expression in L6 myotubes, whereas neither Wy 14,643, a PPAR alpha agonist, nor Pioglitazone, a PPAR gamma agonist, increased it. Therefore, we conclude that UCP3 gene expression is increased by the activation of PPAR delta in L6 myotubes and postulate that PPAR delta mediates at least some part of the increased UCP3 gene expression by fatty acids in skeletal muscle in vivo.

Evaluation of selected polymorphisms of the Mendelian hypertensive disease genes in the Japanese population

It remains to be defined whether molecular variants of the genes underlying Mendelian forms of hypertension play some etiological role in essential hypertension. To pursue this issue, we focused on the following three genes: the epithelial sodium channel (ENaC), 11beta-hydroxysteroid dehydrogenase type 2, and mineralocorticoid receptor genes. Five sequence variations of these genes, which were either previously reported to show significant association with hypertension or identified as "mild" molecular variants, were chosen for our study. Each variation was screened in 247 severe hypertensive patients with early onset (<45 years) and any detectable variations were subsequently characterized in 291 older normotensive subjects (>60 years) for the case-control comparison. We also investigated the significance of association between the tested variants and biochemical parameters reflecting sodium-water homeostasis, such as plasma aldosterone concentration (PAC) and renin activity (PRA). Only the T663A variant (alpha-subunit of ENaC) turned out to be polymorphic in the Japanese population. In disagreement with positive associations previously reported in white and black subjects, we observed no significant association between T663A and hypertension, while allele frequencies of A663 were higher in Japanese (58-64%) compared with a reported prevalence of 29% in whites and 15% in blacks. T663A showed a borderline association (p=0.02) with the PAC/PRA ratio but not with PAC or PRA in the multivariate analysis. Our data did not support the association between Mendelian disease gene variants and essential hypertension in the Japanese. However, the present study did not definitively resolve this issue and further investigation is certainly warranted.

Changes in stroke mortality rates for 1950 to 1997: a great slowdown of decline trend in Japan

BACKGROUND AND PURPOSE

Stroke is the second leading cause of death in Japan. We sought to examine changes in stroke mortality rates by age, sex, and birth cohorts from 1950 to 1997.

METHODS

The numbers of deaths from stroke and the population by age and sex in subjects aged 55 to 79 years between 1950 and 1997 were obtained from national vital statistics. Poisson regression analyses for annual percentage changes were used to explore these trends.

RESULTS

Stroke mortality rates decreased since the mid-1960s for both men and women. Four periods of the decline are identified. In the first period (1950 to 1964), the age-adjusted annual percent changes averaged 0.9% for men (P<0.05) and -0.6% for women (P>0.05). In the second period (1965 to 1974), the annual change averaged -5.0% for men and -5.2% for women (both P<0.01). In the third period (1975 to 1989), the annual change averaged -8.6% for men and -8.7% for women (both P<0.01). In the fourth period (1990 to 1997), the annual change averaged -1.2% for men (P>0.05) and -3.0% for women (P<0.01). In the fourth period, the slowdown of the decline in stroke mortality was most evident in the older age groups of men.

CONCLUSIONS

The findings suggested that along with an increasing aging population, the slowdown in the decline of stroke mortality rates, especially for men, is of considerable concern. Efforts to control stroke should be vigorously continued in the 2000s.

Distribution of twenty-four hour urinary taurine excretion and association with ischemic heart disease mortality in 24 populations of 16 countries: results from the WHO-CARDIAC study

There is considerable interest in the association between taurine (2-aminoethanesufonic acid) and risk of ischemic heart disease (IHD), but little information has been made available on the distribution of taurine in populations around the world. The present study aimed to describe the differences in taurine excretion levels and their associations with IHD mortality rates in 24 populations in 16 countries worldwide. This was a multicenter cross-sectional study. In each center, 100 men and 100 women aged 48-56 years were selected randomly from the local populations. Twenty-four hour urinary taurine excretion was measured using an amino acid analyzer (Hitachi 835, Ibaragi, Japan). Age-adjusted IHD mortality rates in the relevant populations were calculated using the direct standard method. The results indicated that (a) percentiles 25%, 50% and 75% of the distributions of 24-h taurine excretion showed large variations in the study populations. Median values of taurine ranged from 191.6 micromol/day (St John, Canada) to 2,180.6 micromol/day (Beppu, Japan) in males, and from 127.5 micromol/day (Moscow, Russia) to 1,590.0 micromol/day (Beppu, Japan) in females. The highest overall median value of taurine was found in the Japanese population samples, followed by the Chinese samples (Shanghai and Taiwan). European, North American and oceanic Caucasians, however, had much lower median values of taurine, except in the cases of the samples from France and Spain. (b) Median values of taurine were significantly associated negatively with age-adjusted IHD mortality rates across the 24 study population samples in men (R2=0.42, p<0.01), and in women (R2=0.55, p<0.01). These negative associations remained significant after adjustment for serum total cholesterol, body mass index and urinary sodium to potassium ratios. In conclusion, the study provides, for the first time, a cross-sectional database on distribution of 24-h urinary taurine excretion in 24 population samples worldwide. A strong and inverse association between population levels of taurine excretion and IHD mortality was observed.

Increased hydroxyl radicals in the hippocampus of stroke-prone spontaneously hypertensive rats during transient ischemia and recirculation

It has been suggested that stroke-prone spontaneously hypertensive rats (SHRSP) show vulnerability to neuronal damage following transient ischemia. To observe the effect of hydroxyl radicals on neuronal damage in the hippocampus of SHRSP during ischemia and recirculation, we measured the levels of 2,3-dihydroxybenzoic acid (2,3-DHBA), as a biological marker of hydroxyl radicals in the hippocampus of SHRSP, by high pressure liquid chromatography-electrochemical detection. The production of hydroxyl radicals in the hippocampus during the first 20 min of recirculation was a peak in all intervals. The changes in 2,3-DHBA levels during ischemia and recirculation in SHRSP were significantly higher than in Wistar-Kyoto rats. These results suggest that neuronal damage following ischemia and recirculation is, in part, caused by the increase in hydroxyl radicals during ischemia and recirculation.

Cardiovascular risk factors in Tanzania: a revisit

In this assessment of cardiovascular risk factors, we examined the prevalence of selected risk factors according to the World Health Organisation (WHO) CARDIAC Study protocol and compared them with a similar study conducted more than a decade ago. The survey was carried out in Dar es Salaam (D, urban), Handeni (H, rural) and Monduli (Mo, semi-nomadic area). Subjects aged 47-57 were recruited randomly for blood pressure and anthropometrical measurements, 24 h urine collection and blood sampling. A structured questionnaire was used to obtain dietary information. The 1998 survey studied 446 subjects, while the 1987 survey included 496 men and women. The measured weight, body mass index (BMI) and prevalence of obesity (BMI > or = 30 kg/m(2)) increased significantly among women in the 1998 survey in rural Handeni and urban Dar. The overall prevalence of obesity was higher for women in the most recent survey (22.8%, P < 0.0001). Diastolic blood pressure (DBP) was higher in the most recent survey for women in Handeni. The overall prevalence of hypertension (blood pressure > 160/95 mmHg, or antihypertensive drug use), rose to 41.1% in 1998, (P < 0.001) for men and to 38.7% (P < 0.05) for women. The mean total serum cholesterol and prevalence of hypercholesterolaemia increased significantly in the most recent survey in the three studied areas. The overall prevalence of hypercholestrolaemia (serum cholesterol > 5.2 mmol/l) was higher in the 1998 survey for both men (21.8%, P < 0.0001) and women (54.0%, P < 0.0001). The mean HDL cholesterol increased significantly in the most recent survey, with a significant reduction in the mean atherogenic index, though these were still at higher levels (men 5.8, P < 0.0001; women 5.1, P < 0.0001 vs. 1987). A strong positive correlation was observed between blood pressure (SBP and DBP) and body mass index, total serum cholesterol and sodium to potassium ratio. These data suggest that for the past decade there has been an increase in the mean levels and prevalence of selected cardiovascular risk factors in Tanzania.

Glycitein effect on suppressing the proliferation and stimulating the differentiation of osteoblastic MC3T3-E1 cells

Glycitein, as one of the three major isoflavones in soybeans, directly but significantly (about 5%) suppressed the proliferation of MC3T3-E1 and stimulated bone-related protein (alkaline phosphatase (ALP) and osteocalcin (OC)) expression. These results indicate that glycitein suppresses the proliferation of osteoblasts and promotes differentiation from its progenitor.

Ethnic and environmental differences in various markers of dietary intake and blood pressure among Chinese Han and three other minority peoples of China: results from the WHO Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study

Our aim was to examine differences in dietary intake and blood pressure (BP) and their associations in four different ethnic Chinese populations, the Han, the Uygur, the Kazak and Tibetan subjects. This study used a sub-database of the Chinese sample of the WHO-Cardiovascular Diseases and Alimentary Comparison (CARDIAC) Study. The WHO-CARDIAC Study was a multicenter cross-sectional study. In each center, 100 men and 100 women aged 48-56 years were selected at random from the local population. Various markers of dietary intake and their relation with BP were studied. The results of the present study indicated the following. 1) There were significant differences in mean BP and prevalence rates of hypertension, with both being higher in the Kazak and Tibetan subjects than in Han and Uygur subjects. 2) The highest mean body mass index (BMI) was observed in the Kazak subjects, while the highest 24-h urinary sodium (Na) and sodium to potassium (Na/K) ratio excretion were observed in the Tibetan subjects. There were also significant differences in other factors, such as magnesium, 3-methylhistidine (3MH) (a biological marker of animal protein intake) and taurine (a biological marker of seafood intake) excretion levels among the four ethnic peoples. 3) In general, BMI, Na and/or Na/K ratios were positively, and 3MH/creatinine and taurine/creatinine ratios were negatively associated with BP. 4) After adjustment for age, sex and potassium, subjects with obesity (BMI > or =26 kg/m2) had significantly higher relative risk of being hypertensive (HT) than those with BMI<26 kg/m2 in the Han, Uygur and Kazak populations; and subjects with elevated sodium excretion (Na > or =244 mmol/day) had significantly higher relative risk of being HT than those with Na<244 mmol/day in the Han, Uygur and Tibetan populations. In conclusion, mean BP and prevalence rates of hypertension were significantly different among the four ethnic groups. These differences are likely to be due, at least in part, to the differences in several diet-related factors, which in turn are associated with culture and environmental differences. Different health promotion strategies might thus be emphasized in different populations.

Genistein, daidzein and glycitein inhibit growth and DNA synthesis of aortic smooth muscle cells from stroke-prone spontaneously hypertensive rats

Recent studies have reported that estrogen replacement therapy (ERT) reduces the risk of cardiovascular diseases in postmenopausal women. However, mechanisms responsible for this effect are not yet completely understood, and ERT is associated with carcinogenic side effects in women and feminizing effects in men. Because soybean isoflavones, a group of natural phytoestrogens, have only weak estrogenic activity and are not known to have side effects such as carcinogenesis and feminization, we evaluated the effects of genistein, daidzein and glycitein on the growth and DNA synthesis of aortic smooth muscle cells (SMC) from stroke-prone spontaneously hypertensive rats (SHRSP). SMC were cultured in dishes and proliferated on 10% dextran-coated charcoal/fetal bovine serum, and then treated with 0.1-30 micromol/L of genistein, daidzein or glycitein to investigate cell proliferation (cell number) and DNA synthesis (cell proliferation ELISA system), respectively. We also studied their effects on platelet-derived growth factor (PDGF)-BB (20 microg/L)-induced SMC proliferation. Soybean isoflavones inhibited proliferation and DNA synthesis of SMC from SHRSP in a concentration-dependent manner. Inhibition was significant at 3 micromol/L of genistein and 10 micromol/L of both daidzein and glycitein. For significant inhibition of PDGF-BB-induced SMC proliferation, concentrations as low as 0.1 micromol/L of each isoflavone were effective. These isoflavones, with their inhibitory effects on natural and PDGF-BB-induced SMC proliferation, may be useful in attenuatating such proliferation, a basic mechanism involved in atherosclerotic vascular change, thereby preventing atherosclerotic cardiovascular diseases.

Different associations of blood pressure with 24-hour urinary sodium excretion among pre- and post-menopausal women. WHO Cardiovascular Diseases and Alimentary Comparison (WHO-CARDIAC) Study

OBJECTIVE

Having found no definite relationship between blood pressure (BP) and 24h sodium excretion in women aged 48-56 years (in contrast to the results in men of the same age) in the WHO Cardiovascular Diseases and Alimentary Comparison (WHO-CARDIAC) Study, we analyzed the data to investigate whether the sodium-BP association differed between pre- and post-menopausal women.

DESIGN AND METHODS

The WHO-CARDIAC is a multicenter cross-sectional study, involving, as of July 2000, 60 collaborating centers in 25 countries. In each center, 100 men and 100 women aged 48-56 years were selected randomly from the general population of the area. In this report, 2,212 women in 21 centers located in 17 countries worldwide, who had data on menopausal status, were studied.

RESULTS

After adjustment for age, body mass index (BMI) and 24h urinary potassium excretion, 24h sodium excretion was positively and significantly associated with systolic blood pressure (SBP) [pooled regression coefficient: 0.037 (SE 0.01), P < 0.01] and with diastolic blood pressure (DBP) [0.023 (0.006), P< 0.01] in post-menopausal women. Pooled regression coefficients of sodium-BP association were not significant in pre-menopausal women (P< 0.05). Cross-center correlation analyses of the 21 centers showed that 24h sodium excretion was positively associated with SBP and DBP in both pre- and post-menopausal women, and this positive association between sodium excretion and SBP was significant in post-menopausal women (R2 = 0.23, P = 0.029).

CONCLUSION

Different associations between sodium and BP were observed in women with pre- and post-menopausal status. There may be a tendency for salt sensitivity to increase at the menopause.

Leisure-time physical activity and other factors in relation to blood pressure in Japanese-Americans in Hawaii, USA

To examine physical activity at work and during leisure-time as well as other factors related to blood pressure (BP) in Japanese-Americans living in Hilo, Hawaii, USA, we performed a population-based cross-sectional study with a sample of 238 participants aged 42-64 years old. This survey was carried out between 19 February and 1 March 2000 in Hilo. All participants were invited to Hilo Medical Center for a free physical examination and experimental tests including an examination of blood and urine samples. A self-administered health questionnaire was used that included items related to demographics, smoking, alcohol consumption, and habitual physical activity at work and during leisure-time. A summary score of physical activity (PA) was calculated. BP was measured using an automated BP measurement system (Khi machine, VINE Co., Ltd., Kyoto, Japan). The results showed the following. 1) Mean (SD) PA scores at work (WPA) and during leisure-time (LTPA) were 2.9 (0.5) and 2.5 (0.5) in men, and 3.0 (0.5) and 2.4 (0.3) in women, respectively; 2) Pearson correlation analyses (adjustment for age) indicated that WPA and LTPA in men show significant negative associations with SBP and DBP (p<0.05 and p<0.01), while LTPA shows significant negative associations with SBP and DBP in women (p<0.05 and p<0.01). After further adjustment for education, occupation, smoking, and alcohol consumption status, LTPA continued to show significant and negative associations with both SBP and DBP in men (p<0.01) and with DBP alone in women (p <0.01). 3) Hypertensive subjects had significantly lower mean LTPA scores than normotensive men (2.39 vs. 2.61, p<0.05) and women (2.32 vs. 2.45, p<0.05). 4) Body mass index and the ratio of sodium to potassium excretion showed significant and positive associations with SBP and DBP in multiple linear regression analyses. In conclusion, the results further emphasize that the health benefits of LTPA, control of body weight, and reduction in salt intake should continually receive strong attention in population-based high BP control.

The relation of oxidative DNA damage to hypertension and other cardiovascular risk factors in Tanzania

OBJECTIVES

To clarify the mechanism of involvement of oxidative stress in hypertensives, we investigated the relationship between the marker of oxidative DNA damage, urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), and cardiovascular risk factors, such as hypertension and serum glycosylated hemoglobin (HbA1c), among Tanzanians aged 46-58 years who were not on antihypertensive medication.

DESIGN AND METHODS

Sixty subjects (males/females, 28/ 32) were selected randomly from the subjects who completed a 24h urine collection in our epidemiological study at Dar es Salaam, Tanzania in 1998. The subjects were divided into two groups, hypertensive subjects (systolic blood pressure (SBP) > or = 140 mmHg and/or diastolic blood pressure (DBP) > or =90 mmHg) and normotensive subjects (SBP < 140 mmHg and DBP < 90 mmHg) or hyperglycemic subjects (HbA1c > or = 6.0%) and normoglycemic subjects (HbA1c < 6.0%). Biological markers from urine and blood were analyzed centrally in the WHO Collaborating Center.

RESULTS

The mean levels of HbA1c and 8-OHdG were significantly higher in the hypertensive subjects than in the normotensive subjects (P < 0.05). Urinary 8-OHdG was significantly higher in hyperglycemic subjects than in normoglycemic subjects. HbA1c was positively correlated with the 24-h urinary 8-OHdG excretions (r= 0.698, P < 0.0001).

CONCLUSIONS

These findings suggest oxidative DNA damage is increased in hypertensive subjects, and there is a positive correlation between the level of blood glucose estimated as HbA1c and oxidative DNA damage. Hyperglycemia related to insulin resistance in hypertension in Tanzania is associated with increased urinary 8-OHdG.

Association analysis of beta(2)-adrenergic receptor polymorphisms with hypertension in Japanese

Significant evidence has been provided for the pathophysiological involvement of the beta(2)-adrenergic receptor (ADRB2) in hypertension. Among ADRB2 polymorphisms identified to date, 2 amino acid substitutions, Arg16Gly and Gln27Glu, and a promoter variant, T-47C, are considered functionally important. In particular, Arg16Gly was shown to be associated with hypertension in black and white subjects. To investigate the relevance of ADRB2 polymorphisms to hypertension, we undertook an extensive association study in a Japanese population. An association was tested in 2 ways. First, a case-control study was conducted in 842 hypertensive and 633 normotensive subjects. In addition to the overall comparison between case and control groups, each was stratified by body mass index and compared with an independent panel of 525 diabetic subjects. Second, ANOVA and multivariate analyses were performed to test the significance of an association between ADRB2 genotype and the level of blood pressure within the entire population except for 395 subjects who had been under treatment for hypertension. Although no significant association was observed for Arg16Gly and T-47C, 2 analytical methods indicated a marginal association (P:=0.01 to 0.04) between the Glu27 variant and lower blood pressure levels. Given such a normotensive propensity, the odds ratio for Glu27 versus Gln27 allele frequencies was estimated to be 0.74, with a wide confidence interval (95% CI, 0.55 to 0.99) reflecting the low Glu27-allele frequency (6% to 8%) in Japanese. There were no apparent confounding influences of obesity and diabetes on the postulated association. Our data suggest that 3 ADRB2 polymorphisms tested are unlikely to confer principal genetic susceptibility for hypertension in the Japanese population. However, further investigation is warranted to clarify the relevance of ADRB2 polymorphisms to blood pressure regulation.

Prevalence of Alzheimer's disease, vascular dementia and dementia with Lewy bodies in a Japanese population

We studied the prevalence of dementing disorders in a rural town of Japan (Amino-cho), using a door-to-door two-phase design. Of the 170 persons screened as having cognitive impairment, 142 cases were diagnosed as having dementia. The prevalence (cases/100 aged 65 years older) was 3.8 for all types of dementia, 2.1 for Alzheimer's disease (AD), 1.0 for vascular dementia (VD) and 0.7 for other types of dementia. Among other types of dementia, there were four male patients with dementia with Lewy bodies (prevalence: 0.1), but no patients with frontotemporal lobar degeneration. The overall prevalence was higher in women for AD, while that of VD was the same in both sexes. With results similar to many previous studies in Western countries and some recent surveys in Japan, the present sudy clearly showed that AD is more prevalent than VD.

Protective effect of resveratrol on oxidative damage in male and female stroke-prone spontaneously hypertensive rats

1. In the present study, we examined the effect of resveratrol (3,4',5-trihydroxystilbene), a phytoestrogen found in the skins of most grapes, on oxidative DNA damage in male and female stroke-prone spontaneously hypertensive rats (SHRSP). 2. Five-week-old male and female SHRSP were divided into control and resveratrol groups. The resveratrol group was given 1 mg/kg per day, orally, resveratrol by gastric intubation once a day. 3. Following an 8 week feeding period, the levels of 8-hydroxydeoxyguanosine (8-OHdG), produced from deoxyguanosine under conditions of oxidative stress, in the urine of male and female resveratrol-treated SHRSP were significantly lower than that in control SHRSP. 4. The urine of resveratrol-treated male and female SHRSP had lower levels of hydroperoxide compared with control SHRSP, but the difference was not significant. 5. Treatment with resveratrol resulted in a 25 and 30% reduction in plasma glycated albumin in male and female SHRSP, respectively, compared with controls. 6. Gender differences for SHRSP with regard to 8-OHdG, hydroperoxide and glycated albumin levels were not confirmed, resveratrol having similar protective effects on male and female SHRSP. 7. These results indicate that dietary resveratrol: (i) plays a role in suppressing oxidative DNA damage and glycoxidative stress in vivo; and (ii) has similar protective effects in both male and female SHRSP, suggesting that the direct effects of this phytoestrogen on oxidative stress in vivo are not sexually dimorphic.

Reduced production of lactate during hypoxia and reoxygenation in astrocytes isolated from stroke-prone spontaneously hypertensive rats

Lactate production and expressions of monocarboxylate transporter 1 (MCT1) and lactate dehydrogenase (LDH) mRNA after hypoxia and reoxygenation (H/R) were examined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) using astrocytes in culture isolated from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar Kyoto rats (WKY). The basal production of lactate in SHRSP was the same as that observed in WKY. In contrast the lactate levels in SHRSP at 1 and 6 h of reoxygenation after hypoxia were significantly lower than those observed in WKY. In addition LDH and MCT1 mRNA expressions in SHRSP were significantly less strong compared with those in WKY during H/R. These findings indicate that decreased production and slow transport of lactate in SHRSP astrocytes are involved in neuronal energy depletion and possibly encourage neuronal damage, although hereditary weakness of cortical neurons is also related to cell death during H/R.