Plasma reactive carbonyl species: Potential risk factor for hypertension

Abstract

To study the role of oxidative stress in hypertension and pre-hypertension, this study analysed plasma levels of reactive carbonyl species (RCS) in 1204 Chinese Han adults. Results showed a statistically significant positive correlation (p < 0.001) between blood pressure and plasma RCS levels with or without being adjusted for covariates. Multivariate-adjusted odds ratio (OR) illustrated that, compared with the lowest quartile of plasma RCS levels, the highest quartile subjects had a 59% and a 130% increase in the risk for developing pre-hypertension and hypertension, respectively. The multi-interaction analysis manifested that the underlying mechanism of the increase of hypertensive risk or pre-hypertensive risk by overweight and unhealthy lifestyles might, at least in part, be through oxidative stress. In conclusion, these findings suggest that oxidative stress, as indicated by plasma RCS levels, are not the necessary consequence of pre-hypertension or hypertension, but reliable risk factors for developing pre-hypertension or hypertension in Chinese Han adults.     

Plasma protein carbonyl levels and breast cancer risk

To study the role of oxidative stress in breast cancer risk, we analysed plasma levels of protein carbonyls in 1050 cases and 1107 controls. We found a statistically significant trend in breast cancer risk in relation to increasing quartiles of plasma protein carbonyl levels (OR = 1.2, 95% CI = 0.9-1.5; OR = 1.5, 95% CI = 1.2-2.0; OR = 1.6, 95% CI = 1.2-2.1, for the 2(nd), 3(rd) and 4(th) quartile relative to the lowest quartile, respectively, P for trend = 0.0001). The increase in risk was similar for younger (<50 years) and older women, more pronounced among women with higher physical activity levels (0.7 hrs/week for 4(th) quartile versus lowest quartile OR = 2.0, 95% CI = 1.4-3.0), higher alcohol consumption (> or = 15 grams/day for 4(th) quartile versus lowest quartile OR = 2.3, 95% CI = 1.1-4.7), and hormone replacement therapy use (HRT, OR = 2.6, 95% CI = 1.6-4.4 for 4(th) quartile versus lowest quartile). The multiplicative interaction terms were statistically significant only for physical activity and HRT. The positive association between plasma protein carbonyl levels and breast cancer risk was also observed when the analysis was restricted to women who had not received chemotherapy or radiation therapy prior to blood collection. Among controls, oxidized protein levels significantly increased with cigarette smoking and higher fruit and vegetable consumption, and decreased with alcohol consumption >30 grams per day. Women with higher levels of plasma protein carbonyl and urinary 15F(2t)-isoprostane had an 80% increase in breast cancer risk (OR = 1.8, 95% CI = 1.2-2.6) compared to women with levels below the median for both markers of oxidative stress. In summary, our results suggest that increased plasma protein carbonyl levels may be associated with breast cancer risk.     

The prevalence of pre-hypertension and its association to established cardiovascular risk factors in south of Iran

ABSTRACT: BACKGROUND: Pre-hypertension is associated with an increased risk of the development of hypertension and subsequent cardiovascular disease and raises mortality risk. The aim of this study was to determine the prevalence of pre-hypertension and to explore the associations between pre-hypertension and established cardiovascular risk factors in a population-based sample of Iranian adults. Methods: In this cross-sectional study a representative sample of 892 participants aged [greater than or equal to]30 years was selected using a multistage cluster sampling method. After completion of a detailed demographic and medical questionnaire (gender, age, history of diabetes mellitus and hypertension, taking antihypertensive or hypoglycemic agents and history of smoking), all participants were subjected to physical examination, blood lipid profile, blood glucose, anthropometric and smoking assessments, during the years 2009 and 2010. Variables were considered significant at a p-value [less than or equal to] 0.05. Statistical analysis was performed using SPSS version 11.5 software. RESULTS: Pre-hypertension was observed among 300 (33.7%) subjects, 36.4% for men and 31.4% for women (p > 0.05). The pre-hypertensive group had higher levels of blood glucose and triglycerides, higher body mass index and lower percentage of smoking than did the normotensive group. Multivariate logistic regression analysis showed that obesity and overweight were the strongest predictors of pre-hypertension [odds ratio, 2.74: 95% CI (Confidence Interval), 1.62 to 4.62 p<0.001; odds ratio, 2.56, 95% CI, 1.74 to 3.77, p<0.001 respectively].Conclusions: Overweight and obesity has become important in the association with pre-hypertension in Iranian population. Primary prevention strategies should concentrate on reducing overweight and obesity if the prevalence of pre-hypertension is to be diminished in Iranian adults. Key words: pre-hypertension, cardiovascular risk factor, obesity, BMI.     

Shift work is not associated with high blood pressure or prevalence of hypertension

Background

Working mostly at night has been suggested to be associated with upset of chronobiological rhythms and high blood pressure, but the evidence from epidemiological studies is weak.

Methods

In a cross-sectional survey, we evaluated the association between shift work and blood pressure, pre-hypertension and hypertension. In total, 493 nurses, nurse technicians and assistants, were selected at random in a large general hospital setting. Hypertension was diagnosed by the mean of four automatic blood pressure readings ≥140/90 mmHg or use of blood pressure lowering agents, and pre-hypertension by systolic blood pressure ≥120–139 or diastolic blood pressure ≥80–89 mmHg. Risk factors for hypertension were evaluated by a standardized questionnaire and anthropometric measurements. The association between the shift of work and blood pressure, pre-hypertension and hypertension was explored using univariate and multivariate analyses that controlled for risk factors for hypertension by covariance analysis and modified Poisson regression.

Results

The mean age of the participants was 34.3±9.4 years and 88.2% were women. Night shift workers were older, more frequently married or divorced, and less educated. The prevalence of hypertension in the whole sample was 16%, and 28% had pre-hypertension. Blood pressure (after adjustment for confounding) was not different in day and night shift workers. The prevalence of hypertension and pre-hypertension by shift work was not different in the univariate analysis and after adjustment for confounding (all risk ratios  = 1.0).

Conclusion

Night shift work did not increase blood pressure and was not associated with hypertension or pre-hypertension in nursing personnel working in a large general hospital.     

Oxidative stress contributes to sex differences in angiotensin II-mediated hypertension in spontaneously hypertensive rats

NADPH oxidase has been implicated in ANG II-induced oxidative stress and hypertension in males; however, the contribution of oxidative stress to ANG II hypertension in females is unknown. In the present study, we tested the hypothesis that greater antioxidant capacity in female spontaneously hypertensive rats (SHR) blunts ANG II-induced oxidative stress and hypertension relative to males. Whole body and renal cortical oxidative stress levels were assessed in female and male SHR left untreated or following 2 wk of chronic ANG II infusion. Chronic ANG II infusion increased NADPH oxidase enzymatic activity in the renal cortex of both sexes; however, this increase only reached significance in female SHR. In contrast, male SHR demonstrated a greater increase in all measurements of reactive oxygen species production in response to chronic ANG II infusion. ANG II infusion increased plasma superoxide dismutase activity only in female SHR (76 ± 9 vs. 190 ± 7 Units·ml(-1)·mg(-1), P < 0.05); however, cortical antioxidant capacity was unchanged by ANG II in either sex. To assess the functional implication of alterations in NADPH enzymatic activity and oxidative stress levels following ANG II infusion, additional experiments assessed the ability of the in vivo antioxidant apocynin to modulate ANG II hypertension. Apocynin significantly blunted ANG II hypertension in male SHR (174 ± 2 vs. 151 ± 1 mmHg, P < 0.05), with no effect in females (160 ± 11 vs. 163 ± 10 mmHg). These data suggest that ANG II hypertension in male SHR is more dependent on increases in oxidative stress than in female SHR.     

Trends in Prevalence,Awareness, Treatment and Control of Hypertension during 2001-2010 in an Urban Elderly Population of China

Objective

As the most important risk factors of cardiovascular disease, pre-hypertension and hypertension are important public health challenges. Few studies have focused on the trends of pre-hypertension and hypertension specifically for the aging population in China. Given the anticipated growth of the elderly population in China, there is an urgent need to document the conditions of pre-hypertension and hypertension in this aging population.

Methods

We conducted two cross-sectional surveys of Chinese adults aged ≥60 years in 2001 and 2010. A total of 2,272 (943 males, 1,329 females) and 2,074 (839 males, 1,235 females) participants were included in the two surveys, respectively.

Results

The age- and sex-standardized prevalence of hypertension significantly increased from 60.1% to 65.2% from the 2001 to the 2010 survey. Among the participants with hypertension, the awareness, treatment and control of hypertension all significantly increased from 69.8% to 74.5%, 50.3% to 63.7%, and 15.3% to 30.3%, respectively, from 2001 to 2010. A logistic regression showed that a higher education level, a higher BMI, a family history of hypertension and doctor-diagnosed cardiovascular disease were significantly associated with hypertension awareness and treatment.

Conclusion

Hypertension prevalence increased rapidly between the years surveyed. Although the awareness, treatment and control of hypertension improved significantly, the values of these variables remained low. More attention should be given to the elderly because the population is aging worldwide, and urgent action, optimal treatment approaches and proper public health strategies must be taken to prevent and manage hypertension.     

Reactive oxygen species contribute to sleep apnea-induced hypertension in rats

In clinical studies, sleep apnea is associated with hypertension, oxidative stress, and increased circulating endothelin-1 (ET-1). We previously developed a model of sleep apnea by exposing rats to eucapnic intermittent hypoxia (IH-C) during sleep, which increases both blood pressure and plasma levels of ET-1. Because similar protocols in mice increase tissue and plasma markers of oxidative stress, we hypothesized that IH-C generation of reactive oxygen species (ROS) contributes to the development of ET-1-dependent hypertension in IH-C rats. To test this, male Sprague-Dawley rats were instrumented with indwelling blood pressure telemeters and drank either plain water or water containing the superoxide dismutase mimetic, Tempol (4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl, 1 mM). Mean arterial pressure (MAP) and heart rate (HR) were recorded for 3 control days and 14 treatment days with rats exposed 7 h/day to IH-C or air/air cycling (Sham). On day 14, MAP in IH-C rats treated with Tempol (107 +/- 2.29 mmHg) was significantly lower than in untreated IH-C rats (118 +/- 9 mmHg, P < 0.05). Tempol did not affect blood pressure in sham-operated rats (Tempol = 101 +/- 3, water = 101 +/- 2 mmHg). Immunoreactive ET-1 was greater in plasma from IH-C rats compared with plasma from sham-operated rats but was not different from Sham in Tempol-treated IH-C rats. Small mesenteric arteries from IH-C rats but not Tempol-treated IH-C rats had increased superoxide levels as measured by ferric cytochrome c reduction, lucigenin signaling, and dihydroethidium fluorescence. The data show that IH-C increases ET-1 production and vascular ROS levels and that scavenging superoxide prevents both. Thus oxidative stress appears to contribute to increases in ET-1 production and elevated arterial pressure in this rat model of sleep apnea-induced hypertension.     

Pre-Hypertension among Young Adults (20–30 Years) in Coastal Villages of Udupi District in Southern India: An Alarming Scenario

IntroductionAccording to Joint National Committee-7 (JNC-7) guidelines, a systolic blood pressure (SBP) of 120 to 139 mm Hg and/or diastolic blood pressure (DBP) of 80 to 89 mm Hg is considered as pre-hypertension. Existing evidence suggest that the cardiovascular morbidities are increasing among pre-hypertensive individuals compared to normal.ObjectiveTo assess the magnitude and factors associated with pre-hypertension among young adults (20–30 years) in coastal villages of Udupi Taluk (an area of land with a city or town that serves as its administrative centre and usually a number of villages), Udupi District, Karnataka state, India.DesignCommunity based cross sectional studySetting6 (out of total 14) coastal villages of Udupi Taluk, Karnataka state, India.Sample1,152 young adults (age group: 20–30 years) selected by stratified random sampling in 6 coastal villages of Udupi Taluk, Karnataka state, IndiaMethodA semi structured pre-tested questionnaire was used to elicit the details on socio-demographic variables, dietary habits, tobacco use, alcohol consumption, physical activity, family history of hypertension and stress levels. Anthropometric measurements and blood pressure were recorded according to standard protocols. Serum cholesterol was measured in a sub sample of the study population. Multivariate logistic regression was applied to identify the independent correlates of pre-hypertension among young adults (20–30 years).ResultsThe prevalence of pre-hypertension in the study population was 45.2% (95%CI: 42.4–48). Multivariate logistic regression analysis revealed that age group of 25–30 years (adj OR: 4.25, 95% CI: 2.99–6.05), white collared (adj OR: 2.29, 95% CI: 1.08–4.85) and skilled occupation (adj OR: 3.24, 95% CI: 1.64–6.42), students (adj OR: 2.46, 95% CI: 1.22–4.95), using refined cooking oil (adj OR: 0.53, 95% CI: 0.29–0.95), extra salt in meals (adj OR: 2.46, 95% CI: 1.52–3.99), salty food items (adj OR: 6.99, 95% CI: 3.63–13.48), pre-obese (adj OR: 1.66, 95% CI: 1.03–2.67) and obese (adj OR: 9.16, 95% CI: 2.54, 36.4) were the significant correlates of pre-hypertension.ConclusionIn the study population, prevalence of pre-hypertension among young adults (20–30 years) was high (45.2%). Biological (age 25–30 years, pre-obesity and obesity) and behavioral (sedentary occupation, intake of extra salt in meals/salty food and not using refined cooking oil) factors were associated with pre-hypertension. Study emphasizes the need of community based screening of pre-hypertension under National Rural Health Mission. It also provides apt information for the evidence based designing of interventions for lifestyle modifications among high risk young adults in the study area.     

Plasma selenium levels and oxidative stress biomarkers: A gene–environment interaction population-based study

The role of selenium exposure in preventing chronic disease is controversial, especially in selenium-repleted populations. At high concentrations, selenium exposure may increase oxidative stress. Studies evaluating the interaction of genetic variation in genes involved in oxidative stress pathways and selenium are scarce. We evaluated the cross-sectional association of plasma selenium concentrations with oxidative stress levels, measured as oxidized to reduced glutathione ratio (GSSG/GSH), malondialdehyde (MDA), and 8-oxo-7,8-dihydroguanine (8-oxo-dG) in urine, and the interacting role of genetic variation in oxidative stress candidate genes, in a representative sample of 1445 men and women aged 18–85 years from Spain. The geometric mean of plasma selenium levels in the study sample was 84.76 µg/L. In fully adjusted models the geometric mean ratios for oxidative stress biomarker levels comparing the highest to the lowest quintiles of plasma selenium levels were 0.61 (0.50–0.76) for GSSG/GSH, 0.89 (0.79–1.00) for MDA, and 1.06 (0.96–1.18) for 8-oxo-dG. We observed nonlinear dose–responses of selenium exposure and oxidative stress biomarkers, with plasma selenium concentrations above ~110 μg/L being positively associated with 8-oxo-dG, but inversely associated with GSSG/GSH and MDA. In addition, we identified potential risk genotypes associated with increased levels of oxidative stress markers with high selenium levels. Our findings support that high selenium levels increase oxidative stress in some biological processes. More studies are needed to disentangle the complexity of selenium biology and the relevance of potential gene–selenium interactions in relation to health outcomes in human populations.     

延边朝鲜族和汉族脂联素启动子SNPs与原发性高血压的相关性

为了探讨延边朝鲜族和汉族脂联素基因启动子单核苷酸多态性(SNPs)与原发性高血压(EH)的关系, 文章采用PCR产物直接测序方法检测了220例EH患者和268例对照个体的脂联素启动子5个SNPs位点: -11426A>G(rs16861194)、-11391G>A(rs17300539)、-11377C>G(rs62620185)、-11156insCA(rs60806105)、-11043C>T(rs76786086), 氧化酶法测定空腹血糖、甘油三酯、总胆固醇、低密度脂蛋白、高密度脂蛋白, 酶联免疫吸附法(ELISA)测定血浆脂联素和胰岛素。结果显示: (1) -11426A>G、-11377C>G 和-11156insCA 3个位点具有多态性, 且它们的基因型频率分布符合Hardy-Weinberg平衡定律(P>0.05), -11391G>A和-11043C>T位点无多态性; (2) -11426A>G和-11156insCA呈完全连锁不平衡(D’=1; r2=1); (3) -11426G基因频率比较, 朝鲜族(21.10%)高于汉族(12.05%), 汉族EH组高于对照组; -11377C>G的基因型和基因频率在朝鲜族和汉族间及同一民族内EH组和对照组间比较均无统计学意义(P>0.05); (4)单倍型?11426G -11377C的频率, 汉族EH组高于对照组(P<0.05), 朝鲜族EH组和对照组比较无统计学意义(P>0.05); (5)EH组的血浆脂联素水平明显低于对照组(P<0.001)。据此得出结论: (1)首次发现?11426A>G和?11156insCA呈完全连锁不平衡, -11426 A>G的多态性在朝鲜族和汉族中存在民族差异; (2) -11426 G和-11426G -11377C是延边汉族EH的危险因子和危险单倍型, 但不是朝鲜族的; (3)低血浆脂联素是延边朝鲜族和汉族EH的重要危险因素; (4)血浆脂联素水平与-11426A>G基因型无关。     

Increased oxidative stress, the renin-angiotensin system, and sympathetic overactivation induce hypertension in kidney androgen-regulated protein transgenic mice

Gender differences in the incidence and severity of hypertension have suggested the involvement of a sex-dependent mechanism. Transgenic (Tg) mice overexpressing kidney androgen-regulated protein (KAP) specifically in kidney showed hypertension associated with oxidative stress. Reactive oxygen species (ROS) are strongly implicated in the pathological signaling leading to hypertension in a framework that includes renin-angiotensin system (RAS) activation, increased sympathetic activity, and cardiac remodeling. In this report, we observed that plasma levels of angiotensin II and catecholamines were increased in KAP Tg mice, compared with wild-type animals. Systemic administration of Tempol, a membrane-permeative superoxide dismutase mimetic, reduced arterial pressure as well as urinary excretion of oxidative stress markers and reduced both angiotensin II and norepinephrine plasma levels in KAP Tg mice. Intracerebroventricular administration of Tempol also reduced arterial pressure in Tg mice. Moreover, administration of apocynin and DPI, inhibitors of NADPH oxidase, a major source of ROS, also reduced arterial pressure and both angiotensin II and norepinephrine plasma levels in Tg mice. Thus, we analyzed the involvement of the RAS and sympathetic nervous system in KAP Tg mouse hypertension. Both captopril and losartan reduced arterial blood pressure in Tg mice, as also occurred after β-adrenergic blockade with atenolol. Also, intracerebroventricular losartan administration reduced arterial pressure in KAP Tg mice. Our data demonstrate that hypertension in male KAP Tg mice is based on increased oxidative stress, increased sympathetic activity, and RAS activation. Moreover, our results suggest a role for increased oxidative stress in the CNS as a major cause of hypertension in these animals.     

Antenatal antioxidant prevents adult hypertension, vascular dysfunction, and microvascular rarefaction associated with in utero exposure to a low-protein diet

Developmental programming of hypertension is associated with vascular dysfunction characterized by impaired vasodilatation to nitric oxide, exaggerated vasoconstriction to ANG II, and microvascular rarefaction appearing in the neonatal period. Hypertensive adults have indices of increased oxidative stress, and newborns that were nutrient depleted during fetal life have decreased antioxidant defenses and increased susceptibility to oxidant injury. To test the hypothesis that oxidative stress participates in early life programming of hypertension, vascular dysfunction, and microvascular rarefaction associated with maternal protein deprivation, pregnant rats were fed a normal, low protein (LP), or LP plus lazaroid (lipid peroxidation inhibitor) isocaloric diet from the day of conception until delivery. Lazaroid administered along with the LP diet prevented blood pressure elevation, enhanced vasomotor response to ANG II, impaired vasodilatation to sodium nitroprusside, and microvascular rarefaction in adult offspring. Liver total glutathione was significantly decreased in LP fetuses, and kidney eight-isoprostaglandin F2alpha (8-isoPGF(2alpha)) levels were significantly increased in adult LP offspring; these modifications were prevented by lazaroid. Renal nitrotyrosine abundance and blood levels of 1,4-dihydroxynonene and 4-hydroxynonenal-protein adducts were not modified by antenatal diet exposure. This study shows in adult offspring of LP-fed dams prevention of hypertension, vascular dysfunction, microvascular rarefaction, and of an increase in indices of oxidative stress by the administration of lazaroid during gestation. Lazaroid also prevented the decrease in antioxidant glutathione levels in fetuses, suggesting an antenatal mild oxidative stress in offspring of LP-fed dams. These studies support the concept that perinatal oxidative insult can lead to permanent alterations in the cardiovascular system development.     

Oxidative stress in newborn infants with and without asphyxia as measured by plasma antioxidants and free fatty acids

A rapid perfusion of oxygen in infants at birth may cause an increase of oxidative stress. To assess this possibility, we measured levels of blood plasma antioxidants and free fatty acids in 20 normal infants at 0, 1, 3, and 5 days after birth. Plasma levels of the most reactive antioxidant, ascorbic acid, decreased daily to equilibrium values at days 3 and 5. Percentages of oxidized form of coenzyme Q-10 (%CoQ-10) in total coenzyme Q, another good marker of oxidative stress, in infants (25-31%) were significantly higher than those in healthy young adults (4.5%). Plasma levels of total free fatty acids (FFA) in normal infants were highest at day 1 and decreased rapidly thereafter. The content of polyunsaturated fatty acids (PUFA) in total FFA was lowest at day 1 and then increased. Since PUFA are susceptible to oxidation, these changes in FFA composition suggest that oxidative stress is most evident at the initial day of neonatal life. Furthermore, it appears that mono-unsaturated fatty acids such as oleic and palmitoleic acids increase in response to the oxidative loss of PUFA. Similar changes in plasma antioxidants, FFA levels, and FFA compositions were observed in 9 infants with asphyxia. Values of %CoQ-10 in infants with asphyxia were significantly greater than those in normal infants, suggesting that infants with asphyxia have elevated oxidative stress.     

The common variant in the <Emphasis Type="Italic">GSTM1</Emphasis> and <Emphasis Type="Italic">GSTT1</Emphasis> genes is related to markers of oxidative stress and inflammation in patients with coronary artery disease: a case-only study

Recent studies suggest that the common variant in the GSTM1 and GSTT1 genes modifies the risk of coronary artery disease (CAD), however, it is unclear whether the risk of CAD modulated by variants in the GSTM1 and GSTT1 genes was associated with alterations of indices of oxidative stress and inflammation. Our study is an attempt to provide insight into the role of GST genetic variant and markers of oxidative stress and inflammation in CAD patients. A total of 719 Chinese CAD patients were successfully genotyped. Plasma total antioxidant status (TAOS), glutathione(GSH), C-reactive protein (CRP), fibrinogen (FIB) and white blood cell count (WBC) were determined to evaluate the oxidative stress and inflammatory response. The correlations between GSTM1/GSTT1 genotypes and alterations of indices of oxidative stress and inflammation were analyzed. We found GSTM1-0/GSTT1-0 subjects had higher CRP and FIB and lower TAOS compared to patients with wild-type GSTM1/GSTT1 genes. A stepwise elevations in age, the incidences of hypertension and diabetes mellitus, levels of FIB and the number of WBC were associated with increased number of stenosed vessels. Reductions of plasma TAOS and GSH were associated with increased number of stenosed vessels. Our results suggest that GST polymorphisms maybe modify the effect on markers of oxidative stress and inflammation in Chinese CAD patients.     

Plasma F2-isoprostanes are elevated in newborns and inversely correlated to gestational age

F(2)-isoprostanes, prostaglandin F(2)-like compounds formed by free radical-catalyzed lipid peroxidation, are considered the most reliable markers of oxidative stress. It has been repeatedly suggested that newborns are exposed to conditions of oxidative stress resulting from the change from a low oxygen pressure in utero to a high oxygen pressure at birth. We measured the levels of F(2)-isoprostanes in plasma of newborns by gas chromatography/mass spectrometry and we found that F(2)-isoprostanes are significantly higher in term newborns compared to healthy adults. The greatest values were found in preterm newborns in whom F(2)-isoprostanes are even higher than in term babies. Moreover a significant inverse correlation was found between the plasma levels of isoprostanes and the gestational age. A quite normal level of isoprostanes was found in the mothers both at delivery and during pregnancy. Placental total F(2)-isoprostanes (sum of free plus esterified) were significantly higher in preterm compared to term deliveries and such a difference might account for the difference in plasma isoprostanes. Plasma non-protein-bound iron is higher in preterm than in term newborns, even if no correlation was found with plasma F(2)-isoprostanes. Erythrocyte desferrioxamine-chelatable iron content (0 time) and release (24 h of aerobic incubation) are higher in newborns than in adults and in preterm than in term newborns, but again no correlation was found with plasma F(2)-isoprostanes. The marked increase in plasma isoprostanes suggests that oxidative stress is a feature of the physiopathological changes seen in the perinatal period.     

Association of urinary levels of 6-sulfatoxymelatonin (aMT6s) with prevalent and incident hypertension

Laboratory studies indicate that melatonin has beneficial vascular effects. However, epidemiologic studies on the relationship between endogenous levels of melatonin and hypertension in humans are limited. We examined the association of quartile levels of 6-sulfatoxymelatonin (aMT6s) in first morning urines with prevalent and incident hypertension in 777 postmenopausal women who were originally part of a case–control study of breast cancer nested in the Women’s Health Initiative Observational Study. A total of 321 prevalent and 172 incident cases of hypertension were studied. In cross-sectional analyses, higher quartile level of aMT6s was associated with lower odds of hypertension (Q4 versus Q1; odds ratio = 0.57; 95% confidence interval [CI]: 0.3–0.9), after adjustment for age, body mass index and other risk factors. We also examined the association between baseline aMT6s levels and risk of incident hypertension. Compared to women in the lowest quartile of urinary aMT6s, the multivariable-adjusted hazard ratios and 95% CIs of incident hypertension for women in the second, third and highest quartile were 1.16 (0.8–1.8), 0.96 (0.6–1.5) and 1.02 (0.6–1.6), respectively. The mean change in systolic and diastolic blood pressure over 3 years also did not vary by baseline quartile levels of aMT6s. Although we found no evidence of a prospective association between urinary levels of aMT6s and risk of incident hypertension in postmenopausal women, our cross-sectional results provide some possible evidence of a role for physiologic levels of melatonin in hypertension. Additional larger studies are warranted, preferably with a wider range of ages, both genders and multiple melatonin measurements.     

eNOS基因第四内含子a／b多态与湖北汉族人原发性高血压而不是2型糖尿病相关联

目的：探讨内皮型一氧化氮合酶基因（eNOS）与湖北汉族人原发性高血压（EH）和2型糖尿病（T2DM）的关系。方法：采用病例-对照设计,分析了657例样本eNOS第四内含子重复序列多态性a／b,测量了身高、体重、腰围、臀围、收缩压、舒张压、空腹血糖,餐后2小时血糖等临床指标。结果：EH病例组eNOSab＋aa基因型和a等位基因频率显著高于EH对照组（基因型：25．3％vs18．9％,P=0．049;等位基因：13．3％vs9．8％,P=0．045）;而T2DM病例组与T2DM对照组的eNOSab＋aa基因型频率没有显著差异（20．2％vs24．1％,P=0．247）。单因素Logistic回归分析显示eNOSab＋aa基因型是EH的危险因子（OR=1．623,95％CI 1．053—2．506,P=0．029）。多因素回归分析显示,EH的独立风险因素是年龄、体重指数和eNOS基因a／b多态性,而体重指数和腰臀比是T2DM的独立风险因素。结论：eNOS基因a／b多态性是湖北汉族人群EH的一个易感标记,而与T2DM没有相关性。     

Homocysteine as a Risk Factor for Hypertension: A 2-Year Follow-Up Study

Homocysteine (Hcy) is regarded as a risk factor for hypertension, but research on the causal relationship between Hcy and hypertension is limited. In the present study, we prospectively tracked the blood pressure progression of a normotensive population with different Hcy levels over a 2-year period. The incidence of hypertension with increasing Hcy quartiles produced an approximately U-shaped curve, with significance in males. Compared with the third quartile, the risk of hypertension in the first and second quartiles was increased by 1.55 (95% confidence interval [CI] 1.154–2.081) fold and 1.501 (95% CI 1.119–2.013) fold, respectively, with the increase being more significant in males. In conclusion, Hcy is related to hypertension incidence with the results approximating an U-shaped curve. Low Hcy levels might also increase the risk of hypertension.     

Association of urinary iodine concentration with prediabetes/diabetes in adults: Analysis of the NHANES 2005–2016

Background & AimsIodine is required for synthesizing thyroid hormones and regulating human metabolism. Iodine deficiency can lead to thyroid function abnormalities, which are closely associated with disturbances in glucose-insulin homeostasis. Research on the relationship between iodine and diabetes/prediabetes in adults was sparse and inconsistent. We assessed trends in urinary iodine concentration (UIC) and diabetes/prediabetes prevalence and focused on the association between iodine and diabetes/prediabetes among U.S. adults.MethodsWe analyzed the National Health and Nutrition Examination Survey (NHANES) data from the 2005–2016 cycles. Linear regression was employed to evaluate UIC and prediabetes/diabetes prevalence trends over time. Both multiple logistic regression and restricted cubic splines (RCS) were performed to evaluate the association of UIC with diabetes/prediabetes.ResultsA distinctly declining trend in median UIC and a significant increase in diabetes prevalence in U.S. adults from 2005 to 2016 were observed. The fourth quartile of UIC was associated with a 30% lower risk for prediabetes, compared with the first quartile (OR=0.70, 95% CI: 0.56–0.86, P_trend=0.001). However, UIC was not significantly associated with the prevalence of diabetes. The RCS model suggested a significant nonlinear relationship between UIC and the risk of diabetes (P for nonlinearity =0.0147). Stratification analysis showed that the negative associations of UIC with the risk of prediabetes were more pronounced in participants who were men, aged 46–65, overweight, light alcohol drinkers, and nonactive smokers.ConclusionsOverall, the adults’ median UIC in the U.S. population was a declining trend. However, diabetes prevalence increased significantly from 2005 to 2016. Higher UIC was associated with a lower risk of prediabetes.     

Serum Uric Acid Levels and the Risk of Impaired Fasting Glucose: A Prospective Study in Adults of North China

Objective

To prospectively investigate the association between serum uric acid (SUA) level and incidence of impaired fasting glucose (IFG) in adult Chinese.

Methods

We evaluated 13,328 women and 41,350 men without diabetes and IFG. The participants were classified into quintile according to baseline level of SUA. Data were analyzed to examine the association between SUA levels and the incidence of IFG. We used Cox regression models to estimate the relative risk of IFG after adjusting for known risk factors.

Results

For men, the second quintile of SUA has the lowest cumulative incidence of IFG (29.9%); the fifth quintile of SUA has the highest cumulative incidence of IFG (35.6%). After corrected with Cox regression, the first quartile and the fourth quartile have higher cumulative incidence of IFG than the second quintile, with the HR of 1.11(1.05-1.17) and 1.07(1.01-1.13), respectively. For women, the first quartile of SUA has the lowest cumulative incidence of IFG (20.7%), while the fifth quintile of SUA has the highest cumulative incidence of IFG (30.0%). However, there is no significant difference in IFG between different quintile after adjusted with Cox regression.

Conclusions

The results of this prospective study suggest that there is a higher risk of developing IFG in association with low or high SUA concentrations for men. These relationships were independent of other known risk factors. There is no significant correlation in the risk of developing IFG in association with SUA concentrations for women. Analyses excluding participants with hypertension or with hyperlipidemia and analyses with participants stratified by age reached similar conclusion.