Parity and perceived job stress elevate blood pressure in young normotensive working women

This study examined the effect of physiological, behavioral, and psychosocial stressors on blood pressure measured in the work environment, home environment, and during sleep in a sample of 50 normotensive working women (average age = 30.2 +/- 7.4 years; average education = 4.3 years college). The results of separate stepwise regression analyses performed on the pressures measured in each environment showed that perceived job stress (P less than .05) and body fat or mass (P less than .05) significantly elevated systolic pressure in all situations, whereas home stress (P less than .05) and number of children (P less than .05) had the most marked effect on diastolic pressure variation over the day. These results suggest that the daily variation of systolic pressure in working women is related to stress on the job, and that diastolic pressure variation is associated with home stress, which may include stress arising from child care.     

Social stress increases blood pressure and cardiovascular pathology in a normotensive rat model

Territorial stress (TS) elevates blood pressure (BP) in several mammalian species. However, cardiovascular pathology following chronic stress has not been consistently shown in a non-genetic hypertension model. Therefore, the hypothesis tested was that social stress would directly increase: BP, collagen deposition in coronary and mesenteric arteries, and myocardial fibrosis. Wistar-Kyoto (WKY) male rats, four weeks of age, were divided into one of three groups: controls (n = 9), territorial stress (TS, n = 12), and social isolation followed by territorial stress (SITS, n = 11). Blood pressure was measured biweekly, and blood samples biweekly for serum testosterone, corticosterone, epinephrine and norepinephrine. Blood pressure significantly increased in the TS (130 mmHg, p < 0.05) and SITS (150 mmHg, p < 0.05) groups, compared to controls (120 mmHg, ANOVA, F = 6.7, p < 0.001). Coronary collagen was increased 47% in the TS group and 90% in the SITS group compared to controls (p < 0.05). The coronary wall/lumen ratio increased significantly (45%, p < 0.05) in the SITS group compared to the controls. Myocardial fibrosis was increased 27% in the TS group and 74% in the SITS group compared to controls (p < 0.05). In conclusion, stress treatments increased BP and cardiac pathology in a normotensive rat strain.     

Effects of guava intake on serum total and high-density lipoprotein cholesterol levels and on systemic blood pressure.

There is evidence that inclusion of high fiber foods such as oats, fruits and vegetables in the diet can decrease fat intake and modulate blood lipids. To test this hypothesis, 61 group A and 59 group B patients with essential hypertension were administered guava fruit preferably before meals in a foods-to-eat approach rather than foods-to-restrict, in a randomized and single-blind fashion for 12 weeks. At entry into the study, mean age, male sex, mean body mass index, percentages of risk factors and mean levels of blood lipids were comparable between groups A and B. Adherence to guava consumption was assessed by questionnaires and weighing of guava intake by 24-hour recall after 12 weeks of follow-up. Nutrient intakes including saturated and total fat were significantly decreased; carbohydrates, total and soluble fiber and vitamins and mineral intakes were significantly higher in group A than in group B at 12 weeks. There was a significant net decrease in serum total cholesterol (9.9%), triglycerides (7.7%) and blood pressures (9.0/8.0 mm Hg) with a significant net increase in high-density lipoprotein cholesterol (8.0%) after 12 weeks of guava fruit substitution in group A than in group B. By adding moderate amounts of guava fruit in the usual diet, changes in dietary fatty acids and carbohydrates may occur, providing significant amounts of soluble dietary fiber and antioxidant vitamins and minerals without any adverse effects. There is a greater decrease in lipoprotein metabolism and blood pressures.     

Excessive alcohol intake increases the risk of arterial stiffening in men with normal blood pressure.

Excessive alcohol intake is a known atherosclerotic cardiovascular risk factor. However, the relation between excessive alcohol intake and atherosclerotic cardiovascular risk in subjects with normal blood pressure has not been fully elucidated. This cross-sectional study investigated the relationship between alcohol intake and arterial stiffness, as assessed using brachial-ankle pulse wave velocity, in men with normal blood pressure. Middle-aged male workers who were found to have a normal blood pressure during an annual health check-up performed in May-July 2000 (n=1,682) were enrolled in the study. The subjects' laboratory data were analyzed, and information on drinking and smoking habits was obtained by a self-administered questionnaire. The brachial-ankle pulse wave velocity was measured using volume plethysmography. The mean brachial-ankle pulse wave velocities of men with an alcohol intake of 40-59 g/day and > or =60 g/day were larger than those of non-drinkers and men with an alcohol intake of <20 g/day. A multivariate general linear model was used to identify the association between alcohol intake and brachial-ankle pulse wave velocity after controlling for other risk factors using a multivariate analysis. An alcohol intake of more than 60 g of ethanol/day was significantly associated with an elevated brachial-ankle pulse wave velocity, after controlling for conventional atherosclerotic cardiovascular risk factors. In conclusion, the present results suggest that excessive alcohol intake increases the atherosclerotic cardiovascular risk associated with arterial stiffening in men with normal blood pressure.     

Mechanisms by which food intake elevates circulating levels of hyaluronan in humans

OBJECTIVES. Plasma hyaluronan is a potentially useful clinical test, especially in liver disease. It rises after eating, but mechanisms by which this occurs are not known. The study aimed at defining the effect of different food and liquid intake on plasma hyaluronan and to address mechanisms. DESIGN. The effects on plasma hyaluronan of ingestion of high-fat and low-fat meals, glucose solution, and saline, and of intravenous metoclopramide and oral cisapride were defined in healthy fasted subjects by serial measurements over 5 h. Hyaluronan was measured by a radiometric assay. RESULTS. After test meals and glucose ingestion, plasma hyaluronan rose to 1.7-13 times the fasting levels in 11 healthy volunteers. Peak values were observed in most subjects 45-90 min after ingestion and reached levels in six subjects that might suggest the presence of hepatic fibrosis or cirrhosis. No change occurred after ingestion of 0.48 L iso-osmotic NaCl solution, equal in bulk to the glucose solution. Stimulation of gastrointestinal motility with metoclopramide had no effect but oral cisapride induced a pattern of elevated plasma hyaluronan which mimicked that induced by foodstuffs. CONCLUSIONS. Displacement of hyaluronan from gastrointestinal tissues prevails over the increased clearance expected from elevated portal blood flow. The heightened flux of tissue fluid necessary to displace tissue hyaluronan is best explained by vasodilatation in response to ingestion of nutrients, and subsequent increase in intestinal lymph flow, rather than by fluid absorption, together with gut contraction. The discriminating value of plasma hyaluronan in clinical practice may be greatly enhanced by sampling in fasted subjects at rest.     

DASH diet lowers blood pressure and lipid-induced oxidative stress in obesity

Evidence suggests that obesity may raise blood pressure (BP) through oxidative stress-sensitive mechanisms and that the Dietary Approaches to Stop Hypertension combination diet (DASH-CD) may decrease BP by enhancing antioxidant capacity. To address this question, 12 obese patients with high-normal-to-stage 1 hypertension (hypertensives) and 12 lean normotensives were studied on their usual diets and after following the DASH-CD and a low-antioxidant diet in random sequence for 4 weeks each. Acute oxidative stress was induced by a 4-hour infusion of intralipid and heparin. Ferric-reducing activity of plasma (FRAP) and plasma F2-isoprostanes were measured as biomarkers of antioxidant capacity and oxidative stress, respectively. BP was lower in obese hypertensives on the DASH-CD than on the usual and low-antioxidant diets (-8.1+/-1.5/-7.4+/-1.6 mm Hg, P<0.05). BP did not change significantly in lean normotensives after 4 weeks on the DASH-CD but tended to rise on the low-antioxidant diet. FRAP on usual diets was higher in lean subjects than in obese subjects. FRAP increased in obese but not lean volunteers on the DASH-CD compared with usual diet, and the group difference disappeared. F2-isoprostanes increased from baseline during intralipid and heparin in both groups on the low-antioxidant diet but not in obese hypertensives on the DASH-CD. Among free-living obese hypertensives, the DASH-CD raises antioxidant capacity, lowers BP, and reduces oxidative stress induced by acute hyperlipidemia. The findings are consistent with evidence that elevated BP in obese subjects may reflect an imbalance between antioxidant capacity and oxidative stress that is improved by the DASH-CD.     

Vascular oxidative stress precedes high blood pressure in spontaneously hypertensive rats

This study examines whether longitudinal antioxidant treatment initiated in prehypertensive spontaneously hypertensive rats (SHR) can attenuate vascular oxidant stress and prevent blood pressure elevation during development. Male SHR and age-matched Wistar-Kyoto rats (WKY) were treated from 6 to 11 weeks of age with Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidinoxyl) (1 mmol/l in drinking water), a membrane-permeable superoxide dismutase mimetic. Mean systolic blood pressures (SBPs) were measured by tail-cuff Agonist-induced and basal O2- production was measured in thoracic aortas of 6- and 11-week-old SHR and WKY by lucigenin-derived chemiluminescence and oxidative fluorescent microscopy, respectively. SBP of 6-week-old SHR (131 +/- 5 mmHg) and WKY (130 +/- 4 mmHg) were not different; however, 11-week-old SHR SBP (171 +/- 4 mmHg) was significantly greater (p = .0001) than 11-week-old WKY SBP (143 +/- 5 mmHg). Tempol treatment completely, but reversibly, prevented this age-related rise in SHR SBP (SHR + Tempol: 137 +/- 4 mmHg; p < .0001 versus untreated SHR). Agonist-induced vascular O2- was increased in 6- (p = .03) and 11-week-old SHR (p < .0001) and 11-week-old WKY (p = .03) but not in 6-week-old WKY. Long-term Tempol treatment significantly lowered O2- production in both strains. Basal O2- measurements in both 6- and 11-week-old SHR were qualitatively increased compared with age-matched WKY; this increase in SHR was inhibited with in vitro Tempol treatment. These data show that antioxidant treatment to reduce oxidative stress prevents the age-related development of high blood pressure in an animal model of genetic hypertension.     

Influence of salt intake on the daytime-nighttime blood pressure variation in normotensive and hypertensive black subjects.

OBJECTIVE: To evaluate the influence of different salt-intake regimens on the circadian rhythm of blood pressure (daytime-night-time relationship) in normotensive and hypertensive black subjects with different patterns of salt sensitivity. METHODS: Randomized, cross-over study. Twenty normotensive (NT) and 27 hypertensive (HT) black subjects were kept on a low-sodium diet (30 mmol sodium/d, LS) and on a high-sodium diet (300 mmol sodium/d, HS) for 1 week each. On the last day of each regimen, 24 hour ambulatory blood pressure monitoring was performed. RESULTS: Eight normotensives were classified as salt-sensitive (SS), all with haptoglobin phenotypes (FeHap) 1,1 or 1,2, and 12 as salt resistant (SR), 5 with FeHap 2,2. Seventeen hypertensives were classified as SS, all with FeHap 1,1 or 1,2, and 11 as SR, 2 with FeHap 2,2. Salt sensitivity criterium was: difference > 5 mmHg of 24 h mean blood pressure from low sodium to high sodium. The pattern of daytime-nighttime blood pressure relationship between LS and HS was only modified (respectively from dipper to non-dipper) in HT-SS, but not in NT-SS, NT-SR and HT-SR. The percentual drop in nighttime mean blood pressure was about 10% in HT-SR and in NT-SR either under LS or HS. In NT-SS, the percentual night-time drop in mean blood pressure was lower than that of NT-RS (i.e. about 7-8%), but it was not different on LS and on HS. In contrast, in HT-SS, the percentual nighttime drop in mean blood pressure on HS (6%) was significantly lower than that on LS (10%, p < 0.01). In the 27 HT, but not in the NT, changes in the nocturnal drop in mean blood pressure induced by salt restriction correlated positively with the degree of salt sensitivity (r = 0.45, p < 0.05). CONCLUSIONS: In black subjects, the pattern of nighttime-daytime blood pressure relationship appears to be modified from LS to HS diets (or vice-versa) only in SS hypertensive subjects, but neither in NT-SS nor in NT-SS and HT-SR. Only in HT-SS, but not in the other groups, salt restriction shifts the circadian rhythm of blood pressure from a non-dipper to a dipper pattern. We conclude that in black salt-sensitive hypertensives, salt restriction improves the circadian rhythm of blood pressure. This may have important therapeutic consequences on target organ damage associated with non-dipper patterns.     

High potassium intake blunts the effect of elevated sodium intake on blood pressure levels

The purpose of this study was to investigate the influence of dietary potassium on the sodium effect on blood pressure (BP) in the general population and the adherence of current recommendations for sodium and potassium intake. An overnight (12-hour) urine sample was collected in a population-based study to investigate cardiovascular risk. A sub-sample of 1285 subjects (age range, 25–64 years) free from any medication interfering with BP or potassium excretion was studied. Of the participants, 86.0% consumed over 6 g of salt/day and 87.7% less than the recommended intake of potassium (4.7 g). Potassium excretion and the sodium to potassium ratio were significantly related to systolic and diastolic BP only in subjects consuming more than 6 g/day of salt. Subjects in the highest sodium to potassium ratio quartile (surrogate of unhealthy diet) presented 8 mm Hg and 7 mm Hg higher values of systolic and diastolic BP, respectively, when compared with the first quartile, while individuals in the fourth quartile of urinary potassium excretion (healthier diet) showed 6 mm Hg and 4 mm Hg lower systolic and diastolic BP, respectively, compared with the first quartile. Our data indicate that when people have an increased intake of potassium, high intake of sodium is not associated with higher BP.     

Determinants of rise in blood pressure in normotensive children

Thirty-nine initially normotensive children (25 girls) with a large increase in systolic blood pressure (SBP) over a period of 7 years were compared with 78 children with a small increase, matched for age and gender. They were selected from a random sample of 596 Dutch children who were examined at an initial examination and 4 weeks later, and at yearly intervals thereafter. Body weight, height and Quetelet index at baseline were similar in children with a large rise in SBP and those with a small rise. Children with a large increase had a larger weight gain during follow-up than those with a small rise. Parental blood pressure (BP) and parental history of diabetes mellitus and cardiovascular diseases did not differ between the study groups. Cardiovascular reactivity as assessed by a cold-pressor test at baseline did not differ between the study groups, nor did urinary sodium excretion during follow-up. Total tobacco consumption was larger in those with a small increase. Children with a large rise in SBP experienced a larger fall in SBP from the initial to the 4-week examination. The individual variability of BP over the whole observation period did not differ between the study groups. These observations suggest that a fall in BP after a short follow-up period may be indicative of high BP in the years to come.     

Ethanol withdrawal increases blood pressure and vascular oxidative stress: a role for angiotensin type 1 receptors

We evaluated the possible mechanisms underlying the oxidative stress induced by ethanol withdrawal. With this purpose, we verified the role of AT₁ receptors in such response. Male Wistar rats were treated with ethanol 3%–9% (vol./vol.) for 21 days. Ethanol withdrawal was induced by abrupt discontinuation of the treatment. Experiments were performed 48 hours after ethanol discontinuation. Increased plasma levels of angiotensin II were detected after ethanol withdrawal. Losartan (10 mg/kg; p.o. gavage), a selective AT₁ receptor antagonist, impeded the increase in blood pressure induced by ethanol withdrawal. Increased lipoperoxidation and superoxide anion (O₂^?) levels were detected in aortas after ethanol withdrawal, and losartan prevented these responses. Decreased hydrogen peroxide and nitrate/nitrite concentration were detected in aortas after ethanol withdrawal, and losartan prevented these effects. Nitrotyrosine immunostaining in the rat aorta was increased after ethanol withdrawal, and AT₁ blockade impeded this response. Increased expression of PKCδ and p47^phox was detected after ethanol withdrawal, and treatment with losartan prevented these responses. Our study provides novel evidence that ethanol withdrawal increases vascular oxidative stress and blood pressure through AT₁-dependent mechanisms. These findings highlight the importance of angiotensin II in ethanol withdrawal–induced increase in blood pressure and vascular oxidative damage.     

Anthropometric correlates of blood pressure in normotensive Pakistani subjects

Obesity and hypertension are two major inter-related cardiovascular risk factors. Decrease in adiposity is one of the most effective preventive measures not only in decreasing the overall cardiovascular risk but also the blood pressure. This cross-sectional study measured the effect of various measures of adiposity on blood pressure in normal healthy subjects of Pakistani origin. 400 normotensive subjects (247 males and 153 females) were included in this study. Along with data on co-morbid conditions, two blood pressure readings and several anthropometric measurements were recorded. Age and gender specific analysis was done. Following the WHO cutoffs for Asians, about 52% of our sample population was found to be overweight or obese. Age was not associated with blood pressure indices in males; however it was strongly associated with all blood pressure indices in females. Greater Body Mass Index (BMI), Waist Circumference (WC) and Waist to Height Ratio (WHTR) were associated with higher Systolic and Diastolic Blood pressure. Increasing age was also associated with higher levels of BMI, WC and WHTR. Anthropometric variables however, were more strongly associated with blood pressure indices than age in this sample population. In conclusion, we found WC and WHTR to be strongly associated with blood pressure indices in normotensive Pakistani males.     

Determinants of exercise blood pressure response in normotensive and hypertensive women: role of cardiorespiratory fitness

PURPOSE: Exaggerated blood pressure (BP) response during physical exertion is associated with increased risk for cardiovascular events. Furthermore, it may be the predisposing factor for myocardial infarction triggered by physical exertion. The authors have shown that systolic BP achieved after 6 minutes of exercise is the strongest predictor of left ventricular hypertrophy. Furthermore, a 37 mm Hg increase in systolic BP above resting BP at 6 minutes of exercise was the threshold for left ventricular hypertrophy. The purpose of this study was to determine predictors of exercise BP response in normotensive and hypertensive women. METHODS: An exercise tolerance test (Bruce) was performed by 1411 normotensive (resting BP < 140/90 mm Hg) and hypertensive (resting BP > or = 140/90 mm Hg) women. These women were faculty, students, and staff at the University of Maryland, College Park, Maryland, and the George Washington University Medical Center, as well as patients undergoing a routine exercise tolerance test at West Coast Cardiology, Pinellas Park, Florida. Two fitness categories (low-fit and high-fit) were established on the basis of treadmill time to exhaustion adjusted for age. RESULTS: Significant associations were observed among the 6-minute exercise BP and age, body mass index, resting systolic and diastolic BP, heart rate, and exercise time to exhaustion. In a stepwise multiple-regression analysis, the determinants of BP after 6 minutes of exercise were resting systolic BP and treadmill time to exhaustion (R2 = 0.36) for normotensive women and treadmill time to exhaustion and resting systolic BP (R2 = 0.30) for hypertensive women. When fitness categories were contrasted, low-fit women in both the normotensive and hypertensive categories had higher BP and rate-pressure product after 6 minutes of exercise than the high-fit women (P <.05). CONCLUSIONS: Resting systolic BP and cardiorespiratory fitness are determinants of a submaximal exercise BP response for both hypertensive and normotensive women. Low cardiorespiratory fitness is associated with a higher BP response during submaximal exercise, suggesting that increased fitness may attenuate this abnormal rise in BP. Thus, low- to moderate-intensity physical activities for most days of the week should be encouraged for all women to increase cardiorespiratory fitness. This is likely to attenuate an abnormal rise in systolic BP that may occur during routine daily activities and protect against the associated health consequences.     

Reactivity of blood pressure to mental arithmetic stress test, stress-test recovery time, and ambulatory blood pressure in hypertensive and normotensive subjects

BACKGROUND: Laboratory mental stress testing and 24 h ambulatory blood pressure monitoring may analyse reactivity of blood pressure during provoked stress and stressful situations in daily-life, respectively. OBJECTIVE: To evaluate whether the responses to a mental stress test and during the stress-test recovery time were associated with ambulatory blood pressure parameters. METHODS: Fifty-two untreated male subjects (22 normotensives and 30 hypertensives) were subjected both to mental arithmetic stress testing and ambulatory blood pressure monitoring. RESULTS: We found a positive correlation between baseline and peak-test blood pressures during the stress test and 24 h blood pressures. Maximal values of systolic and diastolic blood pressures measured during the 24 h were also correlated to the maximal systolic and diastolic blood pressures reached during the stress test ( P < 0.001). We observed no relationship between reactivity during the stress test and 24 h parameters. On the contrary, changes in diastolic blood pressure during the time of recovery from the stress test (expressed as percentage-change scores) were correlated to the 24 h diastolic blood pressure parameters, the diastolic load being the most closely associated variable. CONCLUSION: The absence of relationships between variations in blood pressure during the provoked stress and ambulatory monitoring parameters indicates that reactivity of blood pressure to an acute stress does not predict the 24 h profile. However, the correlation between the maximal blood pressure measured by ambulatory monitoring and that observed during stress testing indicates that the maximal 24 h values may show the extreme blood pressure response (like the one provoked acutely by a laboratory stress test) of an individual subject. The correlation between the percentage-change score during the recovery time of diastolic blood pressure and the 24 h diastolic load could account forr a lower than normal capacity for recovery of subjects with persistently high blood pressures.     

Habitual excessive dietary salt intake and blood pressure levels in renal transplant recipients

We observed that renal transplant recipients with good graft function (mean serum creatinine level 1.5 mg/dl ± 0.5 SD, N = 68) had dietary salt intakes (estimated from serial measurements of 24-hour sodium excretion rate) which averaged 43 percent higher than that of a comparable group of healthy subjects. There was no correlation between blood pressure levels and salt intake and, despite the high dietary salt intake, hypertension was present in only 29 patients and was usually mild; mean systolic and diastolic blood pressures were 132 ± 10 mm Hg and 89 ± 7 mm Hg, respectively white the patients were receiving ant (hypertensive medication (median number of standard doses of antihypertensive medication was 1.0 doses/ patient per day). These observations suggest that high dietary salt intake does not exert a powerful blood pressure elevating effect, since any effect of high dietary salt intake to raise blood pressure should have been magnified In the renal transplant recipients because of their reduced renal mass and their chronic glucocorticoid therapy.     

糖化血红蛋白水平和血糖波动与氧化应激关系的研究

目的探讨HbA₁c水平、血糖波动与氧化应激(OS)的关系。方法选取2017年8月至2019年8月于山西白求恩医院内分泌科住院的新诊断T2DM患者115例,分为低HbA₁c(5.5%~6.5%)组、中HbA₁c(6.5%~7.5%)组、高HbA₁c(7.5%~8.5%)组,行持续葡萄糖监测,记录包括平均血糖波动幅度(MAGE)、血糖标准差(SDBG)、最大血糖波动幅度(LAGE)及日间血糖平均绝对差(MODD);ELISA法测定OS血清指标8-羟基脱氧鸟苷(8-OHdG),分析HbA₁c水平和血糖波动与8-OHdG的关系。结果与低HbA₁c组比较,中HbA₁c组SDBG、MAGE升高(P<0.05);高HbA₁c组LAGE、SDBG、MAGE及MODD均高于低HbA₁c、中HbA₁c组(P<0.05)。随着HbA₁c水平升高,各组8-OHdG水平依次升高(P<0.01)。Pearson相关性分析显示,HbA₁c水平与LAGE、SDBG、MAGE及MODD呈正相关(P<0.01),高HbA₁c组8-OHdG与MAGE呈正相关(r=0.202,P=0.036)。结论 SDBG、MAGE是反映血糖波动更敏感的指标,HbA₁c<7.5%时显示血糖异常波动。T2DM患者血糖波动随HbA₁c水平升高而增加,OS随血糖波动增加而加重。     

Inhibition of endopeptidase-24.15 decreases blood pressure in normotensive rats

The potent vasodilatory peptide bradykinin is cleaved at the Phe5-Ser6 bond in vitro by the metalloenzyme endopeptidase-24.15 (E.C.3.4.24.15). We now report that intravenous infusion of N-[1-(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Phe-p-aminobenzoate, a specific active site-directed inhibitor of endopeptidase-24.15, produces an immediate drop in mean arterial pressure of as much as 50 mm Hg in pentobarbital-anesthetized, normotensive rats. Arterial pressure recovers within 5 minutes. The B2 bradykinin antagonist [Arg0,Hyp3,Thi5,8,D-Phe7]-bradykinin attenuates the decrease in mean arterial pressure resulting from treatment with the inhibitor. The endopeptidase-24.15 inhibitor potentiates the hypotensive effect of intravenous bradykinin infusion, increasing the maximal effect of the peptide by 47% and increasing the potency by almost 10-fold, while the response to intra-arterial bradykinin is less affected by the inhibitor. These results support a role for endopeptidase-24.15 in the inactivation of endogenous and exogenous bradykinin and suggest a direct involvement of the enzyme in the control of blood pressure.