Effect of satisfaction with social support on blood pressure in normotensive and borderline hypertensive men and women

The relation between blood pressure (BP) and two aspects of social support, perceived satisfaction and structural social support network characteristics, were examined in adults classified as having normal BP or borderline hypertension. Casual BP_s were taken by a trained technician on 3 separate visits, each approximately 1 week apart. Participants were categorized as borderline hypertensive if screening systolic blood pressure (SBP) fell in the range 130-160 mmHg and/ordiastolic blood pressure (DBP) fell in the range 85-100 mmHg; BP_s below these ranges were considered normotensive. Participants underwent ambulatory BP monitoring, Individuals classified as normotensive reported significantly greater support satisfaction than individuals with borderline hypertension. Social network characteristics were not associated with BP. During 24 hr of ambulatory BP monitoring, high perceived support satisfaction was associated with lower SBP and DBP at work, home, and during sleep. These data suggest that perceived satisfaction with social support is associated with lower BP. The presence of social support also may reduce BP levels during daily life. This study was supported by National Institutes of Health (NIH) Grants HL49427, HL49572. HL53724, and MOI-RR-30, National Center far Research Resources, Clinical Research Centers Program, National Institutes of Health.     

Increased ambulatory arterial stiffness index and blood pressure load in normotensive obese patients

ObjectivesIt has been shown that blood pressure (BP) values measured in obese subjects are higher than the individuals with normal weight, even in normotensive limits. However, data concerning the Ambulatory Arterial Stiffness Index (AASI) and blood pressure load in normotensive obese subjects is lacking. This study was aimed to compare the ambulatory arterial stiffness index and blood pressure load in normotensive obese and healthy controls.MethodsOne hundred normotensive obese and one hundred normal weight subjects were included in this study. All subjects underwent 24-hour ambulatory blood pressure monitoring. Ambulatory arterial stiffness index was calculated from 24-hour ambulatory blood pressure monitoring records. Ambulatory arterial stiffness index was defined as one minus the regression slope of unedited 24-h diastolic on systolic blood pressures. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) load values were calculated from 24-hour ambulatory blood pressure monitoring analysis.ResultsAmbulatory arterial stiffness index of the obese subjects was significantly higher than the healthy controls (0.48±0.2 vs. 0.33±0.11, p<0.001). 24-hours systolic blood pressure and diastolic blood pressure loads were significantly higher in obese subjects. Logistic regression analysis revealed that body mass index (BMI) was an independent predictor for an abnormal ambulatory arterial stiffness ındex (≥0.50) (OR: 1.137, 95% CI: 0.915-1.001, p=0.004).ConclusionBlood pressure load and ambulatory arterial stiffness index are increased in normotensive obese patients. Moreover, body mass index is an independent predictor for an abnormal ambulatory arterial stiffness index. Our results indicate that obese subjects are at higher risk for future cardiovascular events despite normal office BP levels.     

Caffeine, extended stress, and blood pressure in borderline hypertensive men

Caffeine increases blood pressure (BP), and its pressor effects are larger in borderline hypertensive (BH) men than in controls. This article extends findings of larger caffeine effects on BP at rest and to brief mental stress in BH to a new analysis of caffeine and prolonged mental stress in BH. In a double-blind, crossover study, 24 male BH (140/90 mmHg < BP < 160/95 mmHg) and 23 normotensive controls who were habitual caffeine consumers (NT; BP < 135/85 mmHg; negative parental history) worked on alternating mental stressors for 35 min after placebo or caffeine (3.3 mg/kg). Caffeine raised systolic blood pressure (SBP) and diastolic blood pressure (DBP) alone and during the extended tasks (all ps < .00001/.00001). BH had larger SBP and DBP increases over all postcaffeine periods (ps < .04/04) and larger DBP rises to the extended tasks after caffeine (p = .007). These combined effects led to undesirably high BPs (> 140/82 mmHg) relative to controls (< 130/75) during the 100 min after caffeine intake. Caffeine taken by BH at times of extended behavioral stress may elevate BP to a clinically meaningful degree. This research was supported by the Medical Research Service of the Department of Veterans Affairs and the National Heart Lung and Blood Institute of the National Institutes of Health, grant numbers HL32050 and HL07640. We thank Barbara McKey and Judith Silverstein for their efforts in data collection and Terrie Thomas for her valuable comments on an earlier version of this article.     

Naloxone effects on blood pressure,analgesia and diuresis in spontaneous hypertensive and normotensive rats

Studies were performed in unanesthetized normotensive and spontaneously hypertensive rats (SHR) to compare the effects of naloxone. In normotensive Wistar rats, naloxone did not change blood pressure (BP) and nociceptive threshold, but it induced a dose-related diuretic response. Whereas in SHR naloxone decreased nociceptive threshold and lowered BP when given intracerebroventricularly, it failed to significantly modify diuresis. These differences between hypertensive and normotensive rats in their responses to naloxone may be explained by the fact that vasopressin (VP) levels and opioid activity are different in SHR.     

Physical activity and blood pressure in normotensive young women

Summary Blood pressure and heart rate were measured in 22 physically active normotensive women, 20±1.7 years old (mean±SD) and in 25 physically non-active normotensive women 20.9± 1.7 years old in supine, sitting and standing positions. Diastolic and mean blood pressures were found to be significantly lower in active women than non-active women. A significant negative correlation was found between maximal oxygen consumption and blood pressure, and it is suggested that aerobic physical activity could be used as non-pharmacological therapy in cases of moderate and borderline hypertension in young women.     

The effect of renal sympathectomy on blood pressure and plasma renin activity in spontaneously hypertensive and normotensive rats

Renal denervation delays the development of hypertension in spontaneously hypertensive (SH) rats. The influence of bilateral surgical renal sympathectomy, verified by fluorescence microscopy, on blood pressure and plasma renin activity in SH and normotensive rats (170–180 g before the sympathectomy) was studied. Neither in SH nor in normotensive rats, did the preoperative systolic blood pressure in the renal-sympathectomized group differ from that in the sham-operated controls. After the sympathectomy, blood pressure in the SH rats increased in 4 weeks only insignificantly, from 160±3 to 172±6 mmHg, while that in the sham-operated SH rats rose from 163±5 to 191±5 mmHg. In normotensive rats, blood pressures in both the renal-sympathectomized and sham-operated groups remained at the pre-operative levels. Thirty days after the operations, plasma renin activity or plasma kininogen in the renal-sympathectomized group did not differ from that in the sham-operated one either in SH or in normotensive rats. The results suggest that the delay in hypertension development produced by renal sympathectomy in SH rats is not mediated by a reduction in renin secretion.     

Supplementation with omega-3 polyunsaturated fatty acids augments brachial artery dilation and blood flow during forearm contraction

Omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have beneficial effects on the heart and vasculature. We tested the hypothesis that 6 weeks of dietary supplementation with DHA (2.0 g/day) and EPA (3.0 g/day) enhances exercise-induced increases in brachial artery diameter and blood flow during rhythmic exercise. In seven healthy subjects, blood pressure, heart rate and brachial artery diameter, blood flow, and conductance were assessed before and during the last 30 s of 90 s of rhythmic handgrip exercise (30% of maximal handgrip tension). Blood pressure (MAP), heart rate (HR), and brachial artery vascular conductance were also determined. This paradigm was also performed in six other healthy subjects who received 6 weeks of placebo (safflower oil). Placebo treatment had no effect on any variable. DHA and EPA supplementation enhanced contraction-induced increases in brachial artery diameter (0.28 ± 0.04 vs. 0.14 ± 0.03 mm), blood flow (367 ± 65 vs. 293 ± 55 ml min−1) and conductance (3.86 ± 0.71 vs. 2.89 ± 0.61 ml min−1 mmHg−1) (P < 0.05). MAP and HR were unchanged. Results indicate that treatment with DHA and EPA enhances brachial artery blood flow and conductance during exercise. These findings may have implications for individuals with cardiovascular disease and exercise intolerance (e.g., heart failure)     

Left atrial pressure in normotensive and spontaneously hypertensive rats

The left atrial pressure in adult spontaneously hypertensive rats (SHR) of the Okamoto strain and normotensive control rat (NCR) was measured via chronically implanted catheters. In SHR left atrial pressure in end-expiration was more than twice as high (10.3±0.4 mmHg) as in NCR (4.6±0.3 mmHg). There was no difference in the intrapleural pressure between the two groups of rats, therefore the enhanced left atrial pressure in SHR represents a real rise in the diastolic filling pressure of its left ventricle. This is considered to be the most important compensation for the earlier reported rightward shift of the Frank-Starling curve in SHR (Hallbäck, Isaksson & Noresson 1975, Noresson et al. 1979a). Without this compensation the stroke volume would have been drastically reduced for the hypertrophied heart.     

Hemodynamics during rest and behavioral stress in normotensive men at high risk for hypertension

Persons at risk for hypertension may show elevated blood pressure (BP) at rest and during mental stress; however, the hemodynamics underlying the BP of those persons at high risk are not well characterized. We chose 21 high risk and 21 low risk men using their parental hypertension history and resting systolic blood pressures on two screenings. Then, on a day of extended rest versus a day with prolonged mental arithmetic and reaction time tasks, we examined whether high risk BP elevations reflected greater vascular resistance or cardiac output. High risk men had raised systolic/diastolic pressures ( F s = 74/15, p s < .0001/.0001) and higher vascular resistance ( F = 6.6, p < .02) with minimal differences in heart rate and cardiac output. This finding implicates vascular resistance as the altered element in BP control in these high risk men tested in a familiar environment with minimal task-related threat.     

Hypoalgesic effect of caffeine in normotensive men and women

Evidence from both hypertensive and normotensive individuals indicate that elevated blood pressure is associated with decreased pain sensitivity. The current study sought to experimentally raise blood pressure using 250 mg caffeine, and investigate its effects on the cold pressor pain experiences of 25 men and 25 women. In a placebo-controlled repeated-measures experiment, caffeine increased systolic and diastolic blood pressure, as well as producing more clearheaded and energetic feelings. Caffeine produced higher pain threshold and pain tolerance levels compared to placebo, and women had a lower tolerance to pain than men. Finally, a significant association was found between caffeine-related increase in systolic blood pressure and caffeine-related increase in pain tolerance. Furthermore, this association was the strongest in women. These results are discussed in light of future directions for pain and hypertension research.     

John Henryism and blood pressure differences among black men

A community probability sample of southern, working-class, black men (N=132)between 17 and 60 years of age was administered a scale to measure the degree to which they felt they could control their environment through hard work and determination. Since the legend of John Henry—the famous, black steeldriver of American folklore—can be understood as a cultural statement about how black Americans must often attempt to control behavioral Stressors through hard work and determination, items for the scale were developed to reflect the theme of John Henryism. It was hypothesized that men scoring below the median on education but above the median on John Henryism would have higher blood pressures than any other group. The data were in line with the prediction, in that men who scored low on education and high on John Henryism had significantly higher diastolic blood pressures than men who scored above the median on both measures. Study findings are discussed in terms of the meaning that education and John Henryism may have for raising or lowering autonomic arousal when individuals encounter behavioral Stressors in everyday life. Preliminary construct validity evidence for the John Henryism Scale is also presented.This research was made possible by a grant from the Robert Wood Johnson Foundation (5938), Biomedical Research Support Funds (2 S07 RR05450-20), and a Research Career Development Award (K04 HL01011) to Sherman A. James from the National Heart, Lung and Blood Institute.     

Peripheral blood flows during colorectal distension in anaesthetised dogs

Distension of the descending colon elicits reflex cardiovascular responses, including increases in heart rate and arterial blood pressure. To study the relative contribution of vasoconstriction in individual vascular beds to this reflex response, experiments were performed on seven dogs anaesthetised with chloralose and instrumented with electromagnetic flowmeters around the superior mesenteric, the left renal and the left external iliac arteries. The colorectal portion of the intestine was distended at constant pressure (36.6 mm Hg, 4.9 kPa mean; range 25–50 mm Hg, 3.3–6.7 kPa) with warm Ringer solution for periods of 2 min. After a set of control distensions, the experiments were performed whilst the reflex rise in arterial pressure was prevented by removal of blood from the arterial tree. In control distensions arterial pressure increased by 11.3±1.5 mm Hg, 1.51±0.12 kPa (mean±SEM). In distensions at constant arterial pressure, peripheral blood flows were altered to different extents in the three territories studied: vascular resistance increased by 30.8±5.6% (P<0.01) in the mesenteric, by 4.1±1.5% (P<0.03) in the renal, and by 15.2±6.8% (NS) in the external iliac bed. We conclude that colorectal distension may reflect activation of a function-specific pathway of the sympathetic nervous system, which leads to much greater vasoconstriction in the splanchnic circulation than in renal or musculocutaneous circulations.     

Central blood volume in spontaneously hypertensive rats and Wistar-Kyoto normotensive rats

Central blood volume and total blood volume were determined in spontaneously hypertensive rats and Wistar Kyoto rats at two ages, 6 and 12 weeks, representing ‘borderline’ hypertension and early ‘established’ hypertension, respectively. A technique was used where plasma and erythrocyte indicators were injected into conscious rats. Blood volume in the cardiopulmonary compartment, present in the ‘resting’ awake steady-state, could then be estimated by sudden freezing of the entire rat. 12 week-old spontaneously hypertensive rats showed a decreased total blood volume, while the fraction of blood contained in the cardiopulmonary area was significantly increased compared with that of normotensive Wistar Kyoto rats. In 6-week-old spontaneously hypertensive rats, total blood volume was only marginally decreased but also here a tendency towards centralization of the blood was seen. Thus, along with the development of hypertension in the spontaneously hypertensive rat their decreasing blood volume tends to become increasingly centralized to the cardiopulmonary area. Both neurohormonal influences and structural wall changes in the low-pressure capacitance side may contribute to this.     

Relationship between plasma homocysteine and blood pressure in hypertensive Northern-Nigerians

AimThe study sought to determine whether there is any relationship between plasma homocysteine and blood pressure levels in Nigerians with essential hypertension.MethodIt was a cross-sectional analytical study done on 120 randomly selected hypertensive patients and 120 normal healthy controls seen at the large Conference hall of the Ahmadu Bello University (ABU) Medical Centre, Zaria as well as the ABU Teaching Hospital, Zaria, Northern-Nigeria. Pearson''s Correlation and Binary Logistic Regression analysis determined the relationship between homocysteine and hypertension.ResultsHyperhomocysteinaemia found in the hypertensive patients (22.8 ± 6.6 µmol/L) differed significantly (p<0.001) from controls (10.9 ± 2.8 µmol/L) with significant (p<0.001), blood pressure difference between both groups. Homocysteine significantly positively correlated with systolic (r = 0.51, p<0.001) and diastolic (r = 0.47, p<0.001) blood pressures in hypertensive subjects. The relation of plasma hcy to hypertension was statistically significant for SBP; OR: 1.08 (95% CI, 1.05–1.11) and DBP; OR: 1.08 (95% CI, 1.03–1.13) in the unadjusted model. When adjusted for confounding variables, hcy was significantly related to SBP; OR: 1.1 (95% CI, 1.04–1.18) but not DBP (p=0.25; OR: 1.06 (95 % CI, 0.96–1.18). The mean plasma folate level was high (115.2 ± 48.0 ng/mL) in the hypertensive subjects. The hyperhomocysteinaemic subjects showed a 2.8 times Odds of developing hypertension.ConclusionThis study showed higher mean plasma homocysteine levels in hypertensives than controls not accounted for by sub-optimal folate levels. Hyperhomocysteinaemia showed a positive relationship to systolic hypertension after adjusting for confounders.     

A blend of sesame oil and rice bran oil lowers blood pressure and improves the lipid profile in mild-to-moderate hypertensive patients

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Prevalence of pre-high blood pressure and high blood pressure among non-overweight children and adolescents using international blood pressure references in developed regions in China

Background: There is a lack of data on the prevalence of pre-high blood pressure (PreHBP) and high blood pressure (HBP), based on recent international blood pressure references, in non-overweight children and adolescents.

Aim: To describe the prevalence of PreHBP and HBP in non-overweight children and adolescents in developed regions of China.

Subjects and methods: In total, 588?097 non-overweight children and adolescents aged 6–17?years from the National Surveys on Chinese Students’ Constitution and Health in 2015 were included.

Results: The prevalence of PreHBP was 13.41% and subjects in urban areas had a higher prevalence of PreHBP (14.14%) than those in rural areas (12.92%). Subjects in regions with a high (13.56%) or moderate (13.61%) socioeconomic status showed a higher prevalence of PreHBP than those in regions with a relatively low socioeconomic status (12.76%). A similar pattern was found for the prevalence of HBP, and the prevalence of HBP was 18.25% for all participants, 20.55% for subjects in urban areas, 16.71% in rural areas, 18.76% in high socioeconomic areas, 18.62% in moderate socioeconomic areas and 16.70% in relatively low socioeconomic areas.

Conclusion: A large proportion of non-overweight children and adolescents had elevated blood pressure and there were urban–rural and socioeconomic disparities in the prevalence of elevated blood pressure.     

Digital and brachial artery blood pressure measurements during peripheral,cold-induced vasoconstriction

Measurements of digital artery blood pressure made using an automated photoplethysmographic method (Finapres), in the middle finger of the left hands of nine male subjects, were compared with pressure measures in the right brachial artery using a method relying on the abolition of Karotkoff sounds during occlusion of the upper arm by a pressure cuff (Dinamap), during a 40-min immersion of the hand in cold (4° C) and thermoneutral (32° C) water. Blood flow in the left index finger was assessed and temperatures of the left and right ring fingers were also measured. Before immersion, systolic pressures in the digital artery were higher than systolic pressures in the brachial artery (P < 0.05), whereas the corresponding diastolic measurements were similar. However, both systolic (P < 0.01) and diastolic (P < 0.05) digital artery measurements increased with time. During cold immersion both systolic and diastolic pressures increased at both sites (P < 0.01), although the digital artery systolic readings rose sharply and then declined, whereas the brachial artery readings were stable. The cold-immersed digital artery diastolic measurements were greater than the brachial artery measurements (P < 0.01) and showed a continuation of the upward trend noted prior to immersion (P < 0.01). Thermoneutral diastolic digital artery measurements also showed this continued trend (P < 0.001). Some individual photoplethysmograph assessments of index finger blood flows showed intermittent vasodilatation, but cold immersion caused a decline in mean flow to 22% of pre-immersion value at 15 min, followed by an increase to 40%. It is concluded that digital artery pressure measurements may not be accurate reflections of more central measurements of blood pressure either quantitatively or qualitatively under conditions could enough to induce peripheral vascular changes.     

Peripheral and central vascular compliances in conscious normotensive and spontaneously hypertensive rats

Changes of left atrial (LAP) and right atrial pressure (RAP) upon 10% and 20% blood volume expansion were studied in conscious spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKR) with intact nervous cardiovascular control. In a separate series the changes of central (CBV) and peripheral (PBV) blood volumes upon similar increases of total blood volume (TBV) were measured as well, throughout using male, adult SHR and WKR in both series. During volume expansion both LAP and RAP increased significantly more in SHR than in WKR, as did CBV, while PBV increased significantly less in SHR than in WKR. Total ‘effective’ vascular compliance, defined as ΔTBV/ΔRAP, was significantly lower in SHR. From the two series of measurements central (CBV/LAP) and peripheral (PBV/RAP) vascular compliances could be separately deduced. Central vascular compliance was nearly 50% lower in SHR than in WKR. However, ‘unstressed’ volume of the peripheral compartment appeared to be rather normal in SHR compared to WKR. It is therefore suggested that the decreased total vascular compliance seen in essential hypertension and in SHR is mainly due to a decreased distensibility of the systemic capacitance vessels.     

Relation of high cytomegalovirus antibody titres to blood pressure and brachial artery flow-mediated dilation in young men: the Cardiovascular Risk in Young Finns Study

Human cytomegalovirus (CMV) infection is associated with a higher risk of cardiovascular disease in immunocompromised organ transplant patients. It has been linked with the pathogenesis of elevated arterial blood pressure. However, controversy exists as to whether CMV infection is associated with endothelial function, and little is known about its role as a potential risk factor for early atherosclerosis development at a young age. We aimed to discover if CMV antibody titres are associated with early vascular changes (carotid intima-media thickness, carotid artery distensibility and brachial artery flow-mediated dilation), blood pressure elevation or other traditional cardiovascular risk factors. CMV antibody titres were measured in 1074 women and 857 men (aged 24-39 years) taking part in the Cardiovascular Risk in Young Finns study. CMV antibody titres were significantly higher in women compared to men. In men, high CMV antibody titres were associated directly with age (P < 0·001) and systolic (P = 0·053) and diastolic (P = 0·002) blood pressure elevation, and associated inversely with flow-mediated dilation (P = 0·014). In women, CMV antibody titres did not associate with any of the analysed parameters. In a multivariate regression model, which included traditional atherosclerotic risk factors, CMV antibody titres were independent determinants for systolic (P = 0·029) and diastolic (P = 0·004) blood pressure elevation and flow-mediated dilation (P = 0·014) in men. High CMV antibody titres are associated independently with blood pressure and brachial artery flow-mediated dilation in young men. This association supports the hypothesis that common CMV infection and/or an immune response to CMV may lead to impaired vascular function at a young age.     

Time-courses in renin and blood pressure during sleep in humans

We previously described a strong concordance between nocturnal oscillations in plasma renin activity (PRA) and the rapid eye movement (REM) and non-REM (NREM) sleep cycles, but the mechanisms inducing PRA oscillations remain to be identified. This study was designed to examine whether they are linked to sleep stage-related changes in arterial blood pressure (ABP). Analysis of sleep electroencephalographic (EEG) activity in the delta frequency band, intra-arterial pressure, and PRA measured every 10 min was performed in eight healthy subjects. Simultaneously, the ratio of low frequency power to low frequency power + high frequency power [LF/(LF + HF)] was calculated using spectral analysis of R--R intervals. The cascade of physiological events that led to increased renin release during NREM sleep could be characterized. First, the LF/(LF + HF) ratio significantly (P < 10(-4) decreased, indicating a reduction in sympathetic tone, concomitantly to a significant (P < 10(- 3) decrease in mean arterial pressure (MAP). Delta wave activity increased (P < 10(-4) 10-20 min later and was associated with a lag of 0-10 min with a significant rise in PRA (P < 10(-4) . Rapid eye movement sleep was characterized by a significant increase (P < 10(-4) in the LF/(LF + HF) ratio and a decrease (P < 10(-4) in delta wave activity and PRA, whereas MAP levels were highly variable. Overnight cross-correlation analysis revealed that MAP was inversely correlated with delta wave activity and with PRA (P < 0.01 in all subjects but one). These results suggest that pressure-dependent mechanisms elicit the nocturnal PRA oscillations rather than common central processes controlling both the generation of slow waves and the release of renin from the kidney.