Hypertension, hormones, and aging

The Accumulation of Key Stroke Risk Factors and Its Association With the Characteristics of Subjects: A Population Based Cross Sectional Study

Background: Evidence has shown that the greater the accumulation of risk factors for stroke, the greater the risk of stroke. Early intervention in the accumulation of risk factors for stroke can effectively reduce the incidence of stroke. The study aimed to investigate the distribution of the number of certain risk factors for stroke (hypertension, hyperlipidemia, overweight and obesity, and diabetes) and to explore the cause of the accumulation of certain stroke risk factors. Methods: A total of 4,052 participants aged 40 years or older were selected by the multistage stratified cluster sampling method in Dehui City in Jilin province, China. Descriptive data analyses were conducted. Multiple regression analyses were used to explore the adjusted association between the accumulation of key stroke risk factors and subjects' lifestyle and demographic characteristics. Results: Overall, 84.1% of the participants in this study had one or more of the four certain risk factors for stroke. The odds ratios (ORs) and 95% confidence intervals (CIs) of having ≥1, ≥2, and ≥3 key stroke risk factors were 1.627 (1.258, 2.103), 1.446 (1.209, 1.728), and 1.394 (1.164, 1.670), respectively, for males compared to females. Similarly, the ORs and 95% CIs of having ≥1, ≥2, and ≥3 key stroke risk factors were 1.227 (1.009, 1.492), 1.256 (1.096, 1.442), and 1.450 (1.262, 1.667), respectively, for partially salty diets compared to normal diets. Compared to people who did not exercise regularly, the ORs and 95% CIs of having ≥1, ≥2, and ≥3 key stroke risk factors were 0.693 (0.544, 0.883), 0.800 (0.679, 0.944), and 0.775 (0.659, 0.913), respectively, for people who regularly exercised. Compared to people who without a family history of cerebrovascular diseases, the ORs and 95% CIs were 1.418 (1.162, 1.732), 1.327 (1.154, 1.525), and 1.209 (1.050, 1.393), for people who with it. Conclusions: Male, partially salty diets, and family history of cerebrovascular diseases were risk factors for the accumulation of certain stroke risk factors while regular physical exercise was a protective factor.

The Role of Beta-Blockers in the Treatment of Hypertension

IMPORTANCE

Two major guide-line committees (JNC-8 and NICE UK) have dropped beta-blockers as first-line therapy in the treatment of hypertension. Also, recent meta-analyses (that do not take age into account) have concluded that beta-blockers are inappropriate first-line agents in the treatment of hypertension. This review seeks to shed some light on the "rights and wrongs" of such actions and conclusions.

OBJECTIVES

Because the pathophysiology of primary/essential hypertension differs in elderly and younger subjects, the latter being closely linked to obesity and increased sympathetic nerve activity, the author sought to clarify the efficacy of beta-blockers in the younger/middle-aged group in reducing the risk of death, and cardiovascular end-points.

EVIDENCE ACQUISITION

Four searches were undertaken, utilising PubMed up to 31st Dec 2015. One search was under the terms "hypertension AND obesity AND sympathetic nerve activity". A second was "hypertension AND plasma noradrenaline/norepinephrine AND survival". A third was "beta-blockers or adrenergic beta-antagonists AND hypertension AND age AND stroke or myocardial infarction or death". A fourth was "meta-analysis of beta-blockers AND hypertension AND age AND death, stroke, myocardial infarction" RESULTS: Diastolic (with or without systolic) hypertension, in contrast to isolated systolic hypertension, occurs primarily in younger subjects, and is linked to overweight/obesity and increased sympathetic nerve activity. In younger/middle-aged hypertensive subjects, high plasma norepinephrine levels are linked (independent of blood pressure) to an increased risk of future cardiovascular events and death. High resting heart rates (a surrogate for high sympathetic nerve activity) likewise predict premature all-cause death, coronary heart disease and cardiovascular events in younger hypertensive subjects. In this younger/middle-aged hypertensive group, antihypertensive agents that increase sympathetic nerve activity (diuretics, dihydropyridine calcium blockers, and angiotensin receptor blockers (ARBs)) do not decrease (and may increase) the risk of myocardial infarction, and are therefore inappropriate first-line agents in this age-group. By contrast, in younger/middle-aged hypertensive subjects (less than 60 years old), meta-analysis has shown that beta-blockers are significantly superior to randomised placebo, and at least as effective as randomised comparator agents, in reducing death/stroke/myocardial infarction. In this younger/middle-aged hypertensive group beta-blockers have been shown (vs randomised placebo or diuretics) to reduce the risk of myocardial infarction by 35-50 %, and stroke by 50-55 % (vs placebo), in non-smoker men. Atenolol was at least as effective as ACE-inhibition (captopril) in reducing all 7 cardiovascular endpoints (including stroke which was reduced by 50 %), vs less tight control of blood pressure, in obese hypertensive subjects with type-2 diabetes (UKPDS study); and after 20 years follow-up, atenolol was significantly (23 %) superior to the ACE-inhibitor in reducing the risk of all-cause death (beta-blockers have anti-cancer properties, which maybe relevant).

CONCLUSIONS AND RELEVANCE

Primary/essential hypertension in younger/middle-age is underpinned by high sympathetic nerve activity. In this age-group high resting heart rates and high plasma norepinephrine levels (independent of blood pressure) are linked to premature cardiovascular events and death. Thus, anti-hypertensive agents that increase sympathetic nerve activity ie diuretics, dihydropyridine calcium blockers, and ARBs, are inappropriate first-line choices in this younger age-group. Beta-blockers perform well vs randomised placebo and other antihypertensive agents regarding reduced risk of death/stroke/myocardial infarction in younger (<60 years) hypertensive subjects, and are a reasonable first-line choice of therapy (certainly in men). These facts should be reflected in the recommendations of guideline committees around the world.

Female sex hormones protect against salt-sensitive hypertension but not essential hypertension

Initial studies found that female Dahl salt-sensitive (DS) rats exhibit greater blood pressure (BP) salt sensitivity than female spontaneously hypertensive rats (SHR). On the basis of the central role played by NO in sodium excretion and BP control, we further tested the hypothesis that blunted increases in BP in female SHR will be accompanied by greater increases in renal inner medullary nitric oxide synthase (NOS) activity and expression in response to a high-salt (HS) diet compared with DS rats. Gonad-intact and ovariectomized (OVX) female SHR and DS rats were placed on normal salt (NS; 0.4% salt) or HS (4% salt) diet for 2 wk. OVX did not alter BP in SHR, and HS diet produced a modest increase in BP. OVX significantly increased BP in DS rats on NS; HS further increased BP in all DS rats, although OVX had a greater increase in BP. Renal inner medullary NOS activity, total NOS3 protein, and NOS3 phosphorylated on serine residue 1177 were not altered by salt or OVX in either strain. NOS1 protein expression, however, significantly increased with HS only in SHR, and this corresponded to an increase in urinary nitrate/nitrite excretion. SHR also exhibit greater NOS1 and NOS3 protein expression than DS rats. These data indicate that female sex hormones offer protection against HS-mediated elevations in BP in DS rats but not SHR. We propose that the relative resistance to HS-mediated increases in BP in SHR is related to greater NOS expression and the ability to increase NOS1 protein expression compared with DS rats.

Home and clinic blood pressure responses in elderly individuals with systolic hypertension

Home blood pressure (BP) monitoring may enhance assessment of BP control. In this 16-week study, men and women 70 years or older with systolic BP between 150 and 200 mm Hg were randomized to receive valsartan/hydrochlorothiazide (V/HCTZ) 160/12.5 mg (n = 128), HCTZ 12.5 mg (n = 128), or V 160 mg (n = 128) for 4 weeks. Participants whose BP was 140/90 mm Hg or higher at weeks 4, 8, or 12 were uptitrated to a maximum of V/HCTZ 320/25 mg. Participants were evaluated by home BP monitoring using an automated device weekly before taking daily study medication (n = 301). Baseline BP ± SD for clinic (165.5 ± 11.8/85.1 ± 9.5 mm Hg) was approximately 3/1 mm Hg greater than home readings (162.5 ± 15.8/84.3 ± 10.2 mm Hg). Reductions in BP ± SEM at week 4 were similar for clinic (12.6 ± 1.0/4.7 ± 0.5 mm Hg) and home (10.9 ± 1.1/3.8 ± 0.5 mm Hg) readings (P = .25/P = .23; clinic versus home); differences between V/HCTZ and HCTZ or V were also similar for both home and clinic readings and results by either technique correlated significantly (P < .0001). Home BP measurements confirm that treatment initiated with V/HCTZ versus monotherapy resulted in greater antihypertensive efficacy. Home BP monitoring, if done with proper technique, provides a reliable indicator of BP control in elderly patients and may help guide drug dosing and titration.

Are we misunderstanding beta-blockers

In myocardial ischaemia and heart failure, beta-blockers with intrinsic sympathomimetic activity (ISA) e.g. pindolol, xamoterol, bucindolol, nebivolol, have performed poorly in reducing morbidity and mortality. In both indications beta-1 blockade is the vital active ingredient. Beta-1 blockade (bisoprolol) is now an alternative first-line choice to Ace-inhibition in the treatment of heart failure. The therapeutic role of beta-blockers in hypertension is less well understood, particularly since the new recommendations in the UK from the NICE committee stating that: 1. beta-blockers are no longer preferred as a routine initial therapy, 2. the combination with diuretics is discouraged due to the risk of induced diabetes, and 3. in younger patients first-choice initial therapy should be an ACE-inhibitor. Recent data from the Framingham Heart Study and other epidemiological studies have indicated that the development of diastolic hypertension in younger subjects is closely linked to weight-increase and an increase in peripheral resistance; such subjects have a high adrenergic drive and cardiac output. In contrast, elderly systolic hypertension mostly arises de novo via poor vascular compliance. Thus in younger, probably overweight, hypertensives (including diabetics) first-line beta-blockade has performed well in preventing myocardial infarction (a fact hidden by meta-analyses that do not take age into account). Conversely, in elderly hypertensives first-line beta-blockade (atenolol) has performed poorly in reducing cardiovascular risk (due to partial beta-2 blockade atenolol evokes metabolic disturbance and does not improve vascular compliance, or effectively lower central aortic pressure or reverse left ventricular hypertrophy). Thus beta-blockers like atenolol are ill-equipped for first-line therapy in elderly hypertension. Some beta-blockers, e.g. bisoprolol (up to 10 mg/day is highly beta-1 selective) and nebivolol (beta-2/3 intrinsic sympathomimetic activity), do improve vascular compliance and cause no metabolic disturbance. Beta-blockers as second-line to low-dose diuretics (which, by improving vascular compliance and increasing sympathetic nerve activity, create an optimal environment for beta-blockade) in elderly hypertension (including diabetics) have performed well in reducing cardiovascular events (this combination has the added bonus of reducing the risk of bone fracture by about 30%). Meta-analyses which include studies where it is unclear whether a diuretic or beta-blocker was a first-line therapy will dilute the benefit stemming from first-line diuretic/second-line beta-blockade. Hypertensives (of all ages) with ischaemia are well suited to beta-blockade.

Cardiovascular reactivity to psychological stressors in late adulthood is predicted by gestational age at birth

The relationships of body size and gestational age at birth with adult blood pressure (BP) are relatively modest compared to their stronger associations with cardiovascular disease. BP reactivity is a strong predictor of cardiovascular morbidity, and it is possible that reactivity, rather than resting level, is determined in utero. We investigated whether body size and gestational age at birth predict BP reactivity during experimentally induced psychosocial stress in late adulthood. A total of 73 men and 80 women born after 36 weeks' gestation in Helsinki, Finland, during 1934-1944 underwent the Trier Social Stress Test (TSST); a standardized psychosocial stress test consisting of a public speech and an arithmetic task. Changes in BP were monitored continuously by a non-invasive finger photoplethysmography (Finometer, FMS, Amsterdam, The Netherlands). The results showed that the most robust early determinant of BP reactivity was gestational age; however, with opposite relationships between the sexes (P for interaction <0.001). A 1-week increase in gestational age was associated with a 3.1 mm Hg (95% confidence interval (CI), 0.2 to 6.0) and 1.2 mm Hg (95% CI, -0.1 to 2.6) decreases in systolic and diastolic BP reactivity in women, but with 5.2 mm Hg (95% CI, 1.9 to 8.4) and 2.3 mm Hg (95% CI, 0.9 to 3.8) increases in men. In conclusion, normal variation in gestational age at birth predicts cardiovascular stress reactivity in later adulthood. Given that hypothalamic-pituitary-adrenal axis contributes to the regulation of autonomic nervous system function and the timing of parturition, and shows well-established sex differences, we speculate a role for early programming of this axis in explaining the findings.

Effect of Aerodiol administration on cerebral blood flow volume in postmenopausal women

OBJECTIVE

The aim of the study was to evaluate the acute effect of the intranasal 17beta-estradiol (Aerodiol, Servier, Chambray-les-Tours, France) administration on cerebral blood flow (CBF) volume.

METHODS

Eighteen healthy women who had been natural postmenopausal for at least 1 year were enrolled in the study. We conducted an experimental, randomized, placebo-controlled, crossover, double-blinded study of the acute effect of 17beta-estradiol on the internal carotid artery (ICA), vertebral artery (VA) and, CBF volume using color duplex sonography.

RESULTS

There were significant increases in the ICA, VA flow volumes and CBF volume after 17beta-estradiol administration compared to placebo measurements. However, there was no statistically significant difference in flow velocities or pulsatility indices.

CONCLUSION

Nasal 17beta-estradiol administration in postmenopausal women causes significant increases in CBF volume due to its vasodilatatory effect on ICA and VA.

Calcium antagonists in patients with type 2 diabetes and hypertension

Hypertension is twice as common in patients with diabetes compared to those without diabetes. It accounts for up to 75% of cardiovascular disease risk leading to the substantial increase in morbidity and mortality. Control of blood pressure in people with diabetes has been shown in randomized controlled trials to decrease cardiovascular risk and improve outcome especially in preventing stroke. A target blood pressure goal of <130/80 mm Hg is currently recommended for patients with diabetes. However, less than 1/3 of these patients achieve such a goal. This is in part due to the inherent difficulty in controlling blood pressure in these patients where hypertension is usually associated with increased salt sensitivity, volume expansion and isolated systolic hypertension. Therefore, patients with diabetes usually require multiple medications for optimal blood pressure control. Calcium channel antagonists have been shown in large clinical trials to be both safe and effective in controlling blood pressure in diabetic patients and will continue to play a major role in the management of hypertension in this population, particularly in the combination therapy that these patients usually require.

The Perindopril Protection Against Recurrent Stroke Study (PROGRESS): clinical implications for older patients with cerebrovascular disease

Blood pressure levels are strongly predictive of the risks of first-ever and recurrent stroke. The benefits of blood pressure-lowering therapy for the prevention of fatal and non-fatal stroke in middle-aged individuals are well established. However, until recently, there has been uncertainty about the consistency of such benefits across different patient groups and in particular, for older people and in those with a history of stroke. This paper discusses the evidence surrounding the effectiveness of blood pressure-lowering therapy, specifically in older patients with a history of stroke, with particular attention paid to the results from the Perindopril Protection Against Recurrent Stroke Study (PROGRESS). PROGRESS was a randomised, double-blind, placebo-controlled trial of 6105 individuals with a history of cerebrovascular disease recruited from 172 hospital outpatient clinics in ten countries. Participants (mean age 64 years; range 26-91 years) were randomly assigned to receive active treatment with an ACE inhibitor-based blood pressure-lowering regimen (perindopril) with or without addition of the diuretic indapamide, or matched placebo. At the end of follow up (mean of 4 years), active treatment reduced the incidence of total stroke by 28% (95% CI 17-38%) and the rate of major vascular events by 26% (95% CI 16-34%). Importantly, benefits of treatment were consistent across key patient subgroups, including those with and without hypertension, patients who were Asian and non-Asian, and for both ischaemic and haemorrhagic strokes subtypes. Current evidence is now strong for clinicians to consider blood pressure-lowering therapy as pivotal in the prevention of stroke, especially in patients with a known history of cerebrovascular disease (and vascular disease, in general), irrespective of blood pressure levels, as soon as patients are clinically stable after an acute stroke or other vascular event. Additional age-specific analyses of the PROGRESS data, together with those from other completed trials, will provide more reliable information about the size of the benefits of blood pressure-lowering therapy, specifically for different age groups, and particularly in the oldest old (those aged >80 years). In the meantime though, an ACE inhibitor plus diuretic treatment regimen that maximises the degree of blood pressure reduction has a good safety profile and is an effective treatment that should be considered in all patients with stroke, including the elderly.

Renal function and renal disease in the elderly: Part I

In all industrialized countries, life expectancy has risen in the past 100 years. The incidence of elderly patients reaching end-stage renal disease (ESRD) and requiring renal replacement therapy has also increased. During the past few decades, the pattern of ESRD has changed significantly with the emerging predominance of elderly patients. The causes of this phenomenon are manifold and include an increasing number of chronic diseases typical of the 'third age', such as type 2 diabetes mellitus and vascular disease. In many species, a consequence of aging includes deterioration of renal function, partly due to structural alterations, and partly as the result of a diminishing blood flow. In humans, the aging kidney is characterized by modifications resulting from organic and functional disturbances. In particular, type 2 diabetes mellitus has emerged as an important condition, the microvascular and macrovascular complications of which are a common cause of morbidity and mortality in older patients. In part I of this review, the morphological and functional changes of the aging kidney will be reviewed, as well as the pathological conditions leading to the loss of renal function in the elderly.

Renal and metabolic effects of caffeine in obese (fa/fa(cp)), diabetic, hypertensive ZSF1 rats

In Western society, the triad of hypertension, metabolic syndrome and obesity (which caries a high risk for renal disease) is increasing, as is the intake of caffeine. However, no information is available regarding the metabolic or renal consequences of caffeine consumption in this complex disease entity. The purpose of this study was to investigate the effects of chronic caffeine consumption on renal function and metabolic status in obese ZSF1 rats, an animal model of obesity, hypertension and the metabolic syndrome. Fifteen, 18-week-old male, obese ZSF1 rats were randomized to drink tap water (Cont, n = 8) or 0.1% solution of caffeine (Caff, n = 7) for 8 weeks. Metabolic and renal function measurements were performed at baseline and after 4 and 8 weeks of treatment. Caffeine treatment significantly (p < 0.05) reduced body weight, food, and fluid consumption and improved insulin sensitivity (fasting insulin 129.6+/-8.1 vs 97.5+/-3.6 microIU/mL; fed insulin 146.3+/-8.5 vs 110.6+/-3.4 microIU/mL; fasting glucose 138.7+/-13.4 vs 145+/-8.0 mg/dL; fed glucose 373+/-19.4 vs 283.3+/-19.6 mg/dL, Cont vs Caff, respectively). After 8 weeks of caffeine treatment, animals were less glycosuric as compared with control group. Area under glucose curves (AUC-glucose) in oral glucose tolerance test did not differ between the two groups (AUC- glucose: 592.5+/-42.7 vs 589.5+/-20.5 mg/dL x h, Cont vs Caff), whereas caffeine treatment significantly decreased AUC of insulin (AUC-insulin: 257.77+/-12.9 vs 198.0+/-5.9 microIU/mL x h, Cont vs. Caff, p<0.05). No differences were found with regard to plasma triglycerides and glycerol levels; however, caffeine significantly increased cholesterol levels after 4 and 8 weeks (2F-Anova, p<0.001). Moreover, caffeine significantly decreased creatinine clearance after 4 and 8 weeks (CrCl, Cont: 3.5+/-0.4, Caff: 2.2+/-0.2 L/kg/day, p<0.05) and increased protein/CrCl ratio (Cont: 323+/-30, Caff: 527+/-33 mg/L/day). Caffeine treatment for 8 weeks tended to increase plasma norepinephrine levels (p<0.06), but the two groups did not differ with regard to plasma renin activity, blood pressure, renal blood flow or and renal vascular resistance. The study indicates that caffeine improves insulin sensitivity but increases plasma cholesterol levels and impairs renal function in obesity with the metabolic syndrome and hypertension. Our results imply that the health consequences of chronic caffeine consumption may depend heavily on underlying pathophysiology process.