Hypothalamic gene expression in w-3 PUFA-deficient male rats before, and following, development of hypertension

Dietary deficiency of ω-3 fatty acids (ω-3 DEF) produces hypertension in later life. This study examined the effect of ω-3 DEF on blood pressure and hypothalamic gene expression in young rats, before the development of hypertension, and in older rats following the onset of hypertension. Animals were fed experimental diets that were deficient in ω-3 fatty acids, sufficient in short-chain ω-3 fatty acids or sufficient in short- and long-chain ω-3 fatty acids, from the prenatal period until 10 or 36 weeks-of-age. There was no difference in blood pressure between groups at 10 weeks-of-age; however, at 36 weeks-of-age ω-3 DEF animals were hypertensive in relation to sufficient groups. At 10 weeks, expression of angiotensin-II1A receptors and dopamine D3 receptors were significantly increased in the hypothalamic tissue of ω-3 DEF animals. In contrast, at 36 weeks, α2a and β1 adrenergic receptor expression was significantly reduced in the ω-3 DEF group. Brain docosahexaenoic acid was significantly lower in ω-3 DEF group compared with sufficient groups. This study demonstrates that dietary ω-3 DEF causes changes both in the expression of key genes involved in central blood pressure regulation and in blood pressure. The data may indicate that hypertension resulting from ω-3 DEF is mediated by the central adrenergic system.

Developmental origins of obesity-related hypertension

1. In the past 30 years the prevalence of obesity and overweight have doubled. It is now estimated that globally over 500 million adults are obese and a further billion adults are overweight. Obesity is a cardiovascular risk factor and some studies suggest that up to 70% of cases of essential hypertension may be attributable, in part, to obesity. Increasingly, evidence supports a view that obesity-related hypertension may be driven by altered hypothalamic signalling, which results in inappropriately high appetite and sympathetic nerve activity to the kidney.

2. In addition to the adult risk factors for obesity and hypertension, the environment encountered in early life may ‘programme’ the development of obesity, hypertension and cardiovascular disease. In particular, maternal obesity or high dietary fat intake in pregnancy may induce changes in fetal growth trajectories and predispose individuals to develop obesity and related sequelae.

3. The mechanisms underlying the programming of obesity-related hypertension are becoming better understood. However, several issues require clarification, particularly with regard to the role of the placenta in transferring fatty acid to the fetal compartment, the impact of placental inflammation and cytokine production in obesity.

4. By understanding which factors are most associated with the development of obesity and hypertension in the offspring, we can focus therapeutic and behavioural interventions to most efficiently reduce the intergenerational propagation of the obesity cycle.

Reversal of vascular macrophage accumulation and hypertension by a CCR2 antagonist in deoxycorticosterone/salt-treated mice

Infiltration of macrophages into the artery wall plays detrimental roles during hypertension by promoting vascular inflammation and endothelial dysfunction, and it occurs via a chemo-attractant action of chemokines on macrophage cytokine receptors. We sought to identify the key chemokine receptors associated with macrophage infiltration into the vascular wall during deoxycorticosterone acetate (DOCA)/salt-induced hypertension in mice and to evaluate the impact of pharmacological inhibition of these receptors on blood pressure and leukocyte accumulation. Mice treated with DOCA/salt for 21 days displayed markedly elevated systolic blood pressure (158±2 versus 114±5 mm Hg in sham group; P<0.0001). Polymerase chain reaction screening via a gene array of 20 chemokine receptors indicated an increased expression of CCR2 in aortas of DOCA/salt-treated mice. Real-time polymerase chain reaction confirmed mRNA upregulation of CCR2 in aortas from DOCA/salt-treated animals and of the CCR2 ligands CCL2, CCL7, CCL8, and CCL12 (all >2-fold versus sham; P<0.05). Flow cytometry revealed 2.9-fold higher macrophage numbers (ie, CD45+ CD11b+ F4/80+ cells) in the aortic wall of DOCA/salt versus sham-treated mice. Intervention with a CCR2 antagonist, INCB3344 (30 mg/kg per day, IP), 10 days after the induction of hypertension with DOCA/salt treatment, reduced the aortic expression of CCR2 mRNA and completely reversed the DOCA/salt-induced influx of macrophages. Importantly, INCB3344 substantially reduced the elevated blood pressure in DOCA/salt-treated mice. Hence, our findings highlight CCR2 as a promising therapeutic target to reduce both macrophage accumulation in the vascular wall and blood pressure in hypertension.

Synthesis of flavonoids and flavonoid-based designed multiple ligands for hypertension

The flavonoids, a family of compounds found in nature, possess a wealth of established health benefits. In this research, a library of novel flavonoid compounds was synthesised for therapeutic evaluation. A particular focus was the attachment of 3ʹ,4ʹ-dihydroxyflavonol, an antioxidant and antihypertensive flavonoid, to other known antihypertensives, to provide dual action compounds for the treatment of hypertension.

Patient engagement strategies used for hypertension and their influence on self-management attributes

Background. Several effective methods to facilitate patient self-management of hypertension are available in primary care. These include direct support from community pharmacists and general practice, and the use of home blood pressure (BP) monitoring. The aim of this study is to establish the prevalence of use of key strategies and to determine their independent relationship with patient self-management attributes.

Methods. A survey of patients with treated hypertension was undertaken in 27 community pharmacies. This established recent use of BP monitoring and advice from health professionals. Patient awareness of BP and targets, appropriateness of BP targets and adherence to anti-hypertensive medications were assessed as indicative self-management outcomes. Predictors of outcomes were determined using binary logistic regression.

Results. Overall, 215 surveys were returned. Two-thirds of patients were aged >65 years, and 45% had conditions warranting tighter BP control (<130/80 mmHg). Almost all patients reported monitoring of their BP in the previous year and 63% could report their most recent BP reading. Just 36% reported knowing a target BP, and 78% of reported targets were within guidelines recommendations. One-fifth (22%) monitored their own BP, and 15% reported non-adherence to medication. Doctors provided the large majority of professional advice. Self-monitoring or documentation of BP readings was independently associated with increased likelihood of BP and target BP being known.

Conclusions. Regular monitoring of BP does not automatically translate to professional advice. Increased uptake of patient self-monitoring should be promoted as a means of enabling self-management.

Duration of obesity and incident hypertension in adults from the Framingham Heart Study

Background: Previous studies exploring the association between obesity and hypertension generally used a single baseline measurement of obesity. The effect of accumulating excess adiposity over time on the risk of hypertension is uncertain. This study aimed to examine the relationship between duration of obesity and incident hypertension using the Framingham Heart Study.

Methods: Two thousand, nine hundred and fifty-three participants aged 30–62 years without baseline hypertension were included. Blood pressure, height and weight were measured biennially. Duration of obesity was calculated. Time to incident hypertension was analysed using time-varying Cox proportional hazards regression with age as the time scale and censoring at time of death or end of follow-up.

Results: Eighty percent of participants developed hypertension (median follow-up 15.9 years). A positive association between obesity duration and incident hypertension was observed in women. There was no longer an association when time-varying BMI was adjusted for (hazard ratio 0.95; (95% confidence interval 0.85–1.05)).

Conclusion: These findings suggest that the mechanism by which excess adiposity may increase blood pressure is primarily immediate and that long-term exposure to obesity does not further increase the risk of developing hypertension beyond the level of BMI attained.

Uteroplacental insufficiency leads to hypertension, but not glucose intolerance or impaired skeletal muscle mitochondrial biogenesis, in 12-month-old rats

Growth restriction impacts on offspring development and increases their risk of disease in adulthood which is exacerbated with "second hits." The aim of this study was to investigate if blood pressure, glucose tolerance, and skeletal muscle mitochondrial biogenesis were altered in 12-month-old male and female offspring with prenatal or postnatal growth restriction. Bilateral uterine vessel ligation induced uteroplacental insufficiency and growth restriction in offspring (Restricted). A sham surgery was also performed during pregnancy (Control) and some litters from sham mothers had their litter size reduced (Reduced litter), which restricted postnatal growth. Growth-restricted females only developed hypertension at 12 months, which was not observed in males. In Restricted females only homeostasis model assessment for insulin resistance was decreased, indicating enhanced hepatic insulin sensitivity, which was not observed in males. Plasma leptin was increased only in the Reduced males at 12 months compared to Control and Restricted males, which was not observed in females. Compared to Controls, leptin, ghrelin, and adiponectin were unaltered in the Restricted males and females, suggesting that at 12 months of age the reduction in body weight in the Restricted offspring is not a consequence of circulating adipokines. Skeletal muscle PGC-1α levels were unaltered in 12-month-old male and female rats, which indicate improvements in lean muscle mass by 12 months of age. In summary, sex strongly impacts the cardiometabolic effects of growth restriction in 12-month-old rats and it is females who are at particular risk of developing long-term hypertension following growth restriction.

Implementation of the diabetes and hypertension guideline lifestyle recommendations in urban Mongolia: A qualitative study of primary care providers

Abstract
Background: Hypertension and diabetes, key risk factors for cardiovascular disease, are significant health problems globally. As cardiovascular disease is one of the leading causes of mortality in Mongolia since 2000, clinical guidelines on arterial hypertension and diabetes were developed and implemented in 2011. This paper explores the barriers and enablers influencing the implementation of these guidelines in the primary care setting.
Methods: A phenomenological qualitative study with semi-structured interviews was conducted to explore the implementation of the diabetes and hypertension guidelines at the primary care level, as well as to gain insight into how practitioners view the usability and practicality of the guidelines. Ten family health centres were randomly chosen from a list of all the family health centres (n = 136) located in Ulaanbaatar City. In each centre, a focus group discussion with nurses (n = 20) and individual interviews with practice doctors (n =10) and practice managers (n= 10) were conducted. Data was analysed using a thematic approach utilising the Theoretical Domains Framework.
Results: The majority of the study participants reported being aware of the guidelines and that they had incorporated them into their daily practice. They also reported having attended guideline training sessions which were focused on practice skill development. The majority of participants expressed satisfaction with the wide range of resources that had been supplied to them by the Mongolian Government to assist with the implementation of the guidelines. The resources, supplied from 2011 onwards, included screening devices, equipment for blood tests, medications and educational materials. Other enablers were the participants’ commitment and passion for guideline implementation and their belief in the simplicity and practicality of the guidelines. Primary care providers reported a number of challenges in implementing the guidelines, including frustration caused by increased workload and long waiting times, time constraints, difficulties with conflicting tasks and low patient health literacy.
Conclusions: This study provides evidence that comprehensive and rigorous dissemination and implementation strategies increase the likelihood of successful implementation of new guidelines in low resource primary care settings. It also offers some key lessons that might be carefully considered when other evidence-based clinical guidelines are to be put into effect in low resource settings and elsewhere.

Implementation of clinical guidelines on diabetes and hypertension in urban Mongolia: a qualitative study of primary care providers' perspectives and experiences

BACKGROUND: Hypertension and diabetes, key risk factors for cardiovascular disease, are significant health problems globally. As cardiovascular disease is one of the leading causes of mortality in Mongolia since 2000, clinical guidelines on arterial hypertension and diabetes were developed and implemented in 2011. This paper explores the barriers and enablers influencing the implementation of these guidelines in the primary care setting.

METHODS: A phenomenological qualitative study with semi-structured interviews was conducted to explore the implementation of the diabetes and hypertension guidelines at the primary care level, as well as to gain insight into how practitioners view the usability and practicality of the guidelines. Ten family health centres were randomly chosen from a list of all the family health centres (n = 136) located in Ulaanbaatar City. In each centre, a focus group discussion with nurses (n = 20) and individual interviews with practice doctors (n = 10) and practice managers (n = 10) were conducted. Data was analysed using a thematic approach utilising the Theoretical Domains Framework.

RESULTS: The majority of the study participants reported being aware of the guidelines and that they had incorporated them into their daily practice. They also reported having attended guideline training sessions which were focused on practice skill development. The majority of participants expressed satisfaction with the wide range of resources that had been supplied to them by the Mongolian Government to assist with the implementation of the guidelines. The resources, supplied from 2011 onwards, included screening devices, equipment for blood tests, medications and educational materials. Other enablers were the participants' commitment and passion for guideline implementation and their belief in the simplicity and practicality of the guidelines. Primary care providers reported a number of challenges in implementing the guidelines, including frustration caused by increased workload and long waiting times, time constraints, difficulties with conflicting tasks and low patient health literacy.

CONCLUSIONS: This study provides evidence that comprehensive and rigorous dissemination and implementation strategies increase the likelihood of successful implementation of new guidelines in low resource primary care settings. It also offers some key lessons that might be carefully considered when other evidence-based clinical guidelines are to be put into effect in low resource settings and elsewhere.

Central proopiomelanocortin but not neuropeptide Y mediates sympathoexcitation and hypertension in fat fed conscious rabbits

OBJECTIVE: High-fat diet (HFD)-induced hypertension in rabbits is neurogenic because of the central sympathoexcitatory actions of leptin. Hypothalamic melanocortin and neuropeptide Y (NPY) neurons are recognized as the major signalling pathways through which leptin exerts its central effects. In this study, we assessed the effects of specific antagonists and agonists to melanocortin and NPY receptors on HFD-induced sympathoexcitation and hypertension. METHODS: Rabbits were instrumented with intracerebroventricular cannula, renal sympathetic nerve activity (RSNA) electrode, and blood pressure telemetry transmitter. RESULTS: After 3 weeks HFD (13.5% fat, n = 12) conscious rabbits had higher RSNA (+3.8  nu, P = 0.02), blood pressure (+8.6  mmHg, P < 0.001) and heart rate (+15  b/min, P = 0.01), and brain-derived neurotrophic factor levels in the hypothalamus compared with rabbits fed a control diet (4.2% fat, n = 11). Intracerebroventricular administration of the melanocortin receptor antagonist SHU9119 reduced RSNA (-2.7  nu) and blood pressure (-8.5  mmHg) in HFD but not control rabbits, thus reversing 100% of the hypertension and 70% of the sympathoexcitation induced by a HFD. By contrast, blocking central NPY Y1 receptors with BVD10 increased RSNA only in HFD rabbits. Intracerebroventricular α-melanocortin stimulating hormone increased RSNA and heart rate (P < 0.001) in HFD rabbits but had no effect in control rabbits. CONCLUSION: These findings suggest that obesity-induced hypertension and increased RSNA are dependent on the balance between greater activation of melanocortin signalling through melanocortin receptors and lesser activation of NPY sympathoinhibitory signalling. The amplification of the sympathoexcitatory effects of α-melanocortin stimulating hormone also indicates that the underlying mechanism is related to facilitation of leptin-melanocortin signalling, possibly involving chronic activation of brain-derived neurotrophic factor.

Undiagnosed hypertension in a rural district in Bangladesh: The Bangladesh Population-based Diabetes and Eye Study (BPDES)

Hypertension is mainly asymptomatic and remains undiagnosed until the disease progresses. The objective of the study was to determine the prevalence of and risk factors for hypertension in rural Bangladesh. Using a population-based cluster random sampling strategy, 3096 adults aged ⩾30 years were recruited from a rural district in Bangladesh. Data collected included two blood pressure (BP) measurements, fasting blood glucose, socio-demographic and anthropometric measurements. Hypertension was defined as systolic BP (SBP) ⩾140 mm Hg or diastolic BP (DBP) ⩾90 mm Hg or self-reported diagnosed hypertension. Logistic regression techniques were used for data analyses. The crude prevalence of hypertension was 40% (95% confidence interval (CI) 38-42%) of which 82% were previously undiagnosed. People from lower socio-economic status (SES) had a significantly higher percentage of undiagnosed hypertension compared with people with higher SES (P<0.001). There was no significant gender difference in severity of hypertension. Males with higher education level compared with no education had a higher prevalence of hypertension (odds ratio 2.34, 95% CI 1.49-3.69). Older age and waist circumference in both genders, and diabetes, lack of physical activity in females were found to be associated with higher prevalence of hypertension. Our research suggests the prevalence of undiagnosed hypertension was higher in the rural area in Bangladesh than that reported from the rural area in neighbouring India and China. Lower SES was associated with a higher risk of undiagnosed hypertension. Public health programs at the grass-roots level must emphasise the provision of primary care and preventive services in managing this non-communicable disease.