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Aims Risk factors for asymptomatic echocardiographic abnormalities that predict symptomatic heart failure (HF) may provide insight into early mechanisms of HF pathogenesis. We examined risk factors associated with asymptomatic echocardiographic structural, systolic, and diastolic abnormalities, separately and in combination, and interactions between risk factors, in the prospective community‐based SCReening Evaluation of the Evolution of New HF (SCREEN‐HF) Study cohort of 3190 participants at increased risk of cardiovascular disease. Methods and results Inclusion criteria were age ≥ 60 years with one or more of hypertension, diabetes, ischaemic heart disease, valvular heart disease, abnormal heart rhythm, cerebrovascular disease, or renal impairment. Exclusion criteria were known HF, ejection fraction mild valve abnormality. Structural, systolic, and diastolic echocardiographic abnormalities were defined according to the Atherosclerosis Risk in Communities study criteria, and risk factors for asymptomatic structural, systolic, and diastolic abnormalities were identified using logistic regression analysis. In multivariable analysis, increased body mass index (BMI), non‐steroidal anti‐inflammatory drug therapy, and alcohol intake were risk factors for isolated structural abnormality, whereas male gender, increased heart rate, atrial fibrillation (AF), angiotensin‐converting enzyme inhibitor therapy, and obstructive sleep apnoea were associated with a lower risk. Moreover, male gender, smoking, increased systolic blood pressure, and physical inactivity were risk factors for isolated systolic abnormality, whereas increased pulse pressure and antihypertensive therapy were associated with a lower risk. Furthermore, increased age, blood pressure, amino‐terminal pro‐B‐type natriuretic peptide level, and warfarin therapy (associated with AF) were risk factors for isolated diastolic abnormality, whereas increased heart rate and triglyceride level (associated with BMI) were associated with a lower risk. The association of increased heart rate with lower risk of structural and diastolic abnormalities was independent of β‐blocker therapy. Interactions between risk factors differed for structural, systolic, and diastolic abnormalities. Conclusions The different risk factors for asymptomatic structural, systolic, and diastolic abnormalities that predict symptomatic HF, and the interactions between risk factors, illustrate how these structural, systolic, and diastolic abnormalities represent unique trajectories that lead to symptomatic HF. Improved understanding of these trajectories may assist in the design of HF prevention strategies.

Aim Heart failure (HF) incidence increases markedly with age. We examined age‐associated longitudinal change in cardiac structure and function, and their prediction by age and cardiovascular disease (CVD) risk factors, in a community‐based cohort aged ≥60 years at increased CVD risk but without HF. Methods and results CVD risk factors were recorded in 3065 participants who underwent a baseline echocardiographic examination, of whom 2358 attended a follow‐up examination 3.8 [median, inter‐quartile range (IQR) 3.5, 4.2] years later. Median age was 71 (IQR 67, 76) years and 55% of participants were male. Age was associated with longitudinal increase in left ventricular (LV) mass index (LVMI); decrease in LV volumes; increase in LV ejection fraction; decrease in mitral annular systolic velocity; decrease in diastolic function (decreased mitral early diastolic annular velocity (e′); and increase in left atrial volume index, mitral peak early diastolic flow velocity (E)/e′ ratio, and tricuspid regurgitant velocity (TRVmax) in men and women, except for TRVmax in men). In multivariable analysis, longitudinal increase in LVMI was explained by CVD risk factors alone, whereas age, together with CVD risk factors, independently predicted longitudinal change in all other echocardiographic parameters. CVD risk factors were differentially associated with longitudinal change in different echocardiographic parameters. Conclusions Whereas the increase in LVMI with age was explained by CVD risk factors alone, age, together with risk factors, independently predicted longitudinal change in all other echocardiographic parameters, providing evidence for age‐specific mechanisms of change in cardiac structure and function as people age. Age‐associated change in LVMI, LV volumes, and diastolic function resembled what might be expected for the evolution of HF with preserved ejection fraction. Given the differential association of different CVD risk factors with longitudinal change in different echocardiographic parameters, therapies aimed at attenuation of age‐associated change in cardiac structure and function, and HF evolution, will likely need to address multiple CVD risk factors.

Aims We investigated whether addition of diastolic dysfunction (DD) and longitudinal strain (LS) to Stage B heart failure (SBHF) criteria (structural or systolic abnormality) improves prediction of symptomatic HF in participants of the SCReening Evaluation of the Evolution of New Heart Failure study, a self‐selected population at increased cardiovascular disease risk recruited from members of a health insurance fund in Melbourne and Shepparton, Australia. Both American Society of Echocardiography and European Association of Cardiovascular Imaging (ASE/EACVI) criteria and age‐specific Atherosclerosis Risk in Communities (ARIC) study criteria, for SBHF and DD, and ARIC criteria for abnormal LS, were examined. Methods and results Inclusion criteria were age ≥60 years with one or more of self‐reported ischaemic or other heart disease, irregular or rapid heart rhythm, cerebrovascular disease, renal impairment, or treatment for hypertension or diabetes for ≥2 years. Exclusion criteria were known HF, or ejection fraction mild valve abnormality detected on previous echocardiography or other imaging. Echocardiography was performed in 3190 participants who were followed for a median of 3.9 (interquartile range: 3.4, 4.5) years after echocardiography. Symptomatic HF was diagnosed in 139 participants at a median of 3.1 (interquartile range: 2.1, 3.9) years after echocardiography. ARIC structural, systolic, and diastolic abnormalities predicted HF in univariate and multivariable proportional hazards analyses, whereas ASE/EACVI structural and systolic, but not diastolic, abnormalities predicted HF. ARIC and ASE/EACVI SBHF criteria predicted HF with sensitivities of 81% and 55%, specificities of 39% and 76%, and C statistics of 0.60 (95% confidence interval: 0.57, 0.64) and 0.66 (0.61, 0.71), respectively. Adding ARIC DD to SBHF increased sensitivity to 94% with specificity of 24% and C statistic of 0.59 (0.57, 0.61), whereas addition of ASE/EACVI DD to SBHF increased sensitivity to 97% but reduced specificity to 9% and the C statistic to 0.52 (0.50, 0.54, P

Background Given the age-related decline in glomerular filtration rate (GFR) in healthy individuals, we examined the association of all-cause death or cardiovascular event with the Kidney age - Chronological age Difference (KCD) score, whereby an individual’s kidney age is estimated from their estimated GFR (eGFR) and the age-dependent eGFR decline reported for healthy living potential kidney donors. Methods We examined the association between death or cardiovascular event and KCD score, age-dependent stepped eGFR criteria (eGFRstep), and eGFR 2 (eGFR60) in a community-based high cardiovascular risk cohort of 3837 individuals aged ≥60 (median 70, interquartile range 65, 75) years, followed for a median of 5.6 years. Results In proportional hazards analysis, KCD score ≥ 20 years (KCD20) was associated with increased risk of death or cardiovascular event in unadjusted analysis and after adjustment for age, sex and cardiovascular risk factors. Addition of KCD20, eGFRstep or eGFR60 to a cardiovascular risk factor model did not improve area under the curve for identification of individuals who experienced death or cardiovascular event in receiver operating characteristic curve analysis. However, addition of KCD20 or eGFR60, but not eGFRstep, to a cardiovascular risk factor model improved net reclassification and integrated discrimination. KCD20 identified individuals who experienced death or cardiovascular event with greater sensitivity than eGFRstep for all participants, and with greater sensitivity than eGFR60 for participants aged 60–69 years, with similar sensitivities for men and women. Conclusions In this high cardiovascular risk cohort aged ≥60 years, the KCD score provided an age-adapted measure of kidney function that may assist patient education, and KCD20 provided an age-adapted criterion of eGFR-related increased risk of death or cardiovascular event. Further studies that include the full age spectrum are required to examine the optimal KCD score cut point that identifies increased risk of death or cardiovascular event, and kidney events, associated with impaired kidney function, and whether the optimal KCD score cut point is similar for men and women. Trial registration ClinicalTrials.gov NCT00400257, NCT00604006, and NCT01581827.

BACKGROUND: Effective management of cardiovascular and chronic kidney disease risk factors offers longer, healthier lives and savings in healthcare. AIM: To examine risk factor management in participants of the SCReening Evaluation of the Evolution of New Heart Failure study, a self-selected population at increased cardiovascular disease risk recruited from members of a health insurance fund in Melbourne and Shepparton, Australia. METHODS: Inclusion criteria were age ≥ 60 years with one or more self-reported ischaemic or other heart diseases, irregular or rapid heart rhythm, cerebrovascular disease, renal impairment or treatment for hypertension or diabetes for ≥2 years. Exclusion criteria were known heart failure or cardiac abnormality on echocardiography or other imaging. Medical history, clinical examination, full blood examination and biochemistry (without lipids and glycated haemoglobin (HbA1c)) were performed for 3847 participants on enrolment, and blood pressure, lipids and HbA1c were measured 1-2 years after enrolment for 3203 participants. RESULTS: Despite 99% of 3294 participants with hypertension receiving antihypertensive medication, half had blood pressures >140/90 mmHg. Approximately 77% of participants were overweight or obese, with one third being obese. Additionally, 74% of participants at high cardiovascular disease risk had low-density lipoprotein cholesterol levels ≥2 mmol/L, one third of diabetic participants had HbA1c >7%, 22% had an estimated glomerular filtration rate < 60 mL/min/1.73m2 , and substantial proportions had under-utilisation of antiplatelet therapy and anticoagulation for atrial fibrillation and were physically inactive. CONCLUSIONS: This population demonstrated substantial potential to reduce cardiovascular and renal morbidity and mortality and healthcare costs through more effective management of modifiable risk factors.

Background Body mass index †Deceased. (BMI) is a risk factor for heart failure with preserved ejection fraction (HFpEF). Design We investigated the threshold BMI and sex-specific waist circumference associated with increased HFpEF incidence in the SCReening Evaluation of the Evolution of New Heart Failure (SCREEN-HF) study, a cohort study of a community-based population at increased cardiovascular disease risk. Methods Inclusion criteria were age ≥60 years with one or more of self-reported hypertension, diabetes, heart disease, abnormal heart rhythm, cerebrovascular disease or renal impairment. Exclusion criteria were known heart failure, ejection fraction Results HFpEF incidence rates were higher for BMI ≥27.5 kg/m2 than for BMI 2, and for waist circumference >100 cm (men) or > 90 cm (women) than for waist circumference ≤94 cm (men) or ≤ 83 cm (women) in Poisson regression analysis. Semiparametric proportional hazards analyses confirmed these BMI and waist circumference thresholds, and exceeding these thresholds was associated with an attributable risk of HFpEF of 44–49%. Conclusions Both central obesity and overweight were associated with increased HFpEF incidence. Although a randomised trial of weight control would be necessary to establish a causal relationship between obesity/overweight and HFpEF incidence, these data suggest that maintenance of BMI and waist circumference below these thresholds in a community similar to that of the SCREEN-HF cohort may reduce the HFpEF incidence rate by as much as 50%.

Aims We investigated which serum amino-terminal pro-B-type-natriuretic peptide (NT-proBNP) levels inform heart failure (HF) risk in a community-based population at increased cardiovascular disease (CVD) risk. Methods and results Inclusion criteria were age ≥ 60 years with one or more of self-reported hypertension, diabetes, heart disease, abnormal heart rhythm, cerebrovascular disease, or renal impairment. Exclusion criteria were known HF, ejection fraction (EF) 76% and specificities of 47–69% for 5-year prediction of total HF in men and women in all three age groups. Sensitivities were ≥ 75% in most subgroups according to body mass index, estimated glomerular filtration rate, and the presence or absence of atrial fibrillation, pacemaker, or CVD, and for the prediction of HFpEF, HFrEF and VHF. Conclusion Age-specific serum NT-proBNP levels inform prognosis, and hence therapeutic decisions, regarding HF risk in individuals at increased CVD risk.

BackgroundThe lack of effective therapies for heart failure with preserved ejection fraction (HFpEF) reflects an incomplete understanding of its pathogenesis.DesignWe analysed baseline risk factors for incident HFpEF, heart failure with reduced ejection fraction (HFrEF) and valvular heart failure (VHF) in a community-based cohort.MethodsWe recruited 2101 men and 1746 women ≥60 years of age with hypertension, diabetes, ischaemic heart disease (IHD), abnormal heart rhythm, cerebrovascular disease or renal impairment. Exclusion criteria were known heart failure, left ventricular ejection fraction mild in severity. Median follow-up was 5.6 (IQR 4.6–6.3) years.ResultsMedian time to heart failure diagnosis in 162 participants was 4.5 (IQR 2.7–5.4) years, 73 with HFpEF, 53 with HFrEF and 36 with VHF. Baseline age and amino-terminal pro-B-type natriuretic peptide levels were associated with HFpEF, HFrEF and VHF. Pulse pressure, IHD, waist circumference, obstructive sleep apnoea and pacemaker were associated with HFpEF and HFrEF; atrial fibrillation (AF) and warfarin therapy were associated with HFpEF and VHF and peripheral vascular disease and low platelet count were associated with HFrEF and VHF. Additional risk factors for HFpEF were body mass index (BMI), hypertension, diabetes, renal dysfunction, low haemoglobin, white cell count and β-blocker, statin, loop diuretic, non-steroidal anti-inflammatory and clopidogrel therapies, for HFrEF were male gender and cigarette smoking and for VHF were low diastolic blood pressure and alcohol intake. BMI, diabetes, low haemoglobin, white cell count and warfarin therapy were more strongly associated with HFpEF than HFrEF, whereas male gender and low platelet count were more strongly associated with HFrEF than HFpEF.ConclusionsOur data suggest a major role for BMI, hypertension, diabetes, renal dysfunction, and inflammation in HFpEF pathogenesis; strategies directed to prevention of these risk factors may prevent a sizeable proportion of HFpEF in the community.Trial registration numberNCT00400257, NCT00604006 and NCT01581827.

Summary Angiogenesis and inflammation are causative factors in the development of neovascular retinopathies. These processes involve the retinal endothelium and the retinal immune cells, microglia. The renin-angiotensin system contributes to retinal injury via the actions of the type 1 angiotensin receptor (AT1R). However, it has been suggested that prorenin, the initiator of the renin-angiotensin system cascade, influences retinal injury independently from the AT1R. We evaluated whether prorenin induced a pro-angiogenic and pro-inflammatory response in retinal endothelial cells and a pro-inflammatory phenotype in retinal microglia. Primary cultures of retinal endothelial cells and microglia were studied. Rat recombinant prorenin (2 nmol/L) stimulated the proliferation and tubulogenesis of retinal endothelial cells; it increased the levels of pro-angiogenic factors, vascular endothelial growth factor, angiopoietin-1, and tyrosine kinase with immunoglobulin and epidermal growth factor homology domains, and pro-inflammatory factors, intercellular adhesion molecule-1 and monocyte chemoattractant protein-1, relative to the controls. The messenger RNA levels of the (pro)renin receptor were also increased. These effects occurred in the presence of the AT1R blocker candesartan (10 μmol/L) and the renin inhibitor aliskiren (10 μmol/L). Microglia, which express the (pro)renin receptor, elicited an activated phenotype when exposed to prorenin, which was characterized by increased levels of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, tumour necrosis factor-α, interleukin-6, and interleukin-1β and by decreased levels of interleukin-10 and arginase-1 relative to controls. Candesartan did not influence the effects of prorenin on retinal microglia. In conclusion, prorenin has distinct pro-angiogenic and pro-inflammatory effects on retinal cells that are independent of the AT1R, indicating the potential importance of prorenin in retinopathy.

Caillon et al1 report that angiotensin (Ang) II infusion increased blood pressure, decreased endothelial function, and increased γδ T-cell numbers and activation in the spleen of mice, and that the blood pressure and endothelial responses were abrogated by Tcrδ gene knockout and blunted by γδ T-cell depletion with an anti–T-cell receptor (TCR) γδ antibody. They also report that systolic blood pressure was associated with whole blood TCR γ constant region gene expression in a cohort of patients who had undergone coronary angiography. They conclude that γδ T cells mediate Ang II–induced blood pressure elevation, vascular injury, and T-cell activation in mice, and speculate that γδ T …

Background There is debate whether the J-curve relationship between cardiac event risk and DBP is because of inherent cardiac risk or is a consequence of blood pressure (BP) lowering therapy. Methods We examined the association between the cardiovascular risk marker amino-terminal-pro-B-type natriuretic peptide (NT-proBNP) and DBP in 1781 women and 2211 men aged at least 60 years with one or more cardiovascular risk factors; exclusion criteria were known heart failure or cardiac abnormality on a cardiac imaging study. Results The lowest median serum NT-proBNP levels were for DBP 85-89 mmHg for both women and men. DBP less than 70 mmHg in women and less than 80 mmHg in men was associated with higher NT-proBNP levels than the levels at DBP 85-89 mmHg, and this relationship was present for those with SBP equal to or less than 140 and SBP greater than 140 mmHg. In conditional logistic regression models, the association of elevated NT-proBNP levels with low DBP in women was no longer statistically significant after adjustment for age, ischaemic heart disease (IHD), pulse rate, atrial fibrillation, haemoglobin and glomerular filtration rate, whereas the association in men was no longer statistically significant after adjustment for age and IHD. By contrast, the association between elevated NT-proBNP levels and low DBP remained statistically significant after adjustment for the number of antihypertensive drug classes alone or together with all antihypertensive drugs, including β-blocker therapy. Conclusion There was a J-curve relationship between the cardiovascular risk marker NT-proBNP and DBP that was explained by the clinical variables and not by the BP-lowering therapy.

We assessed left ventricular dysfunction in a population at high risk for heart failure (HF), and explored associations between ventricular function, HF risk factors and NT-proB natriuretic peptide (NT-proBNP).3550 subjects at high risk for incident HF (≥60 years plus ≥1 HF risk factor), but without pre-existing HF or left ventricular dysfunction, were recruited. Anthropomorphic data, medical history and blood for NT-proBNP were collected. Participants at highest risk (n = 664) (NT-proBNP highest quintile;30.0 pmol/L) and a sample (n = 51) from the lowest NT-proBNP quintile underwent echocardiography. Participants in the highest NT-proBNP quintile, compared to the lowest, were older (74 years vs. 67 years; p0.001) and more likely to have coronary artery disease, stroke or renal impairment. In the top NT-proBNP quintile (n = 664), left ventricular systolic impairment was observed in 6.6% (95% CI: 4 to 8%) of participants and was associated with male gender, coronary artery disease, hypertension and NT-proBNP. At least moderate diastolic dysfunction was observed in 24% (95% CI 20 to 27%) of participants and was associated with diabetes and NT-proBNP. In this high risk population, NT-proBNP was associated with left ventricular systolic impairment (p0.001) and moderate to severe diastolic dysfunction (p0.001) after adjustment for age, gender, coronary artery disease, diabetes, hypertension and obesity.A high burden of ventricular dysfunction was observed in this high risk group. Combining NT-proBNP and HF risk factors may identify those with ventricular dysfunction. This would allow resources to be focused on those at greatest risk of progression to overt HF.

Background Myocardial microvascular dysfunction has been implicated in the pathogenesis of myocardial infarction (MI). We tested the hypothesis that patients with MI have lower microvasculature density in myocardium remote from the site of infarction than patients with similar extent of coronary artery disease (CAD) without MI and examined the relationship between myocardial capillary length density and plasma levels of angiogenesis-related biomarkers. Methods We analyzed biopsies from non-ischemic left ventricular (LV) myocardium and measured plasma levels of angiogenesis-related biomarkers in patients undergoing coronary artery bypass graft surgery, 57 without previous MI (no-MI) and 27 with recent non-ST-segment-elevation MI (NSTEMI). Comparison was made with biopsies from 31 aortic stenosis (AS) patients and 6 patients with "normal" LV without CAD. Results Myocardial microvascular density of NSTEMI patients was approximately half the density of no-MI patients, and similar to AS patients. Whereas the reduced microvascular density of AS patients was accounted for by their cardiomyocyte hypertrophy, this was not the case for NSTEMI patients, who had higher diffusion radius/cardiomyocyte width ratio than no-MI, "normal" LV, and AS patients. NSTEMI patients had lower plasma levels of carboxymethyl lysine and low molecular weight fluorophores, higher vascular endothelial growth factor (VEGF) receptor-1/VEGF-A ratio, and higher endostatin and hepatocyte growth factor levels than no-MI patients. Conclusions Recent MI was associated with reduced microvasculature density in myocardium remote from the site of infarction and alteration in plasma levels of angiogenesis-related biomarkers.

Impaired diastolic function is associated with increased morbidity and mortality, but antecedents and predictors of progression to heart failure (HF) are not well understood. We examined associations between NT-proBNP, HF risk factors, and diastolic function in a population at high risk for incident HF.A total of 3550 subjects at high risk for incident HF (≥60 years plus ≥1 HF risk factor), but without pre-existing HF or LV dysfunction were recruited. Participants at highest risk (n = 664) (NT-proBNP in the highest quintile254 pg/mL) underwent echocardiography. Moderate or severe diastolic dysfunction was observed in 25% [95% confidence interval (CI) 21-29%] of participants. Age (P = 0.001), male gender (P = 0.03), diabetes (P = 0.03), and NT-proBNP (P = 0.002) were associated with severity of diastolic dysfunction after adjustment for HF risk factors and LVEF. In regression analysis, log-transformed NT-proBNP was also associated with LV mass index (P = 0.05), left atrial size (P0.0001), and Doppler ratio of the mitral valve E/e' (P = 0.001). Multiple HF risk factors were present in the majority of participants (70%), but no association was observed between diastolic dysfunction and the number of risk factors reported (P = 0.3).Diastolic dysfunction was observed in one in four of these high risk subjects (≥ 60 years, HF risk factor, NT-proBNP254 pg/mL). NT-proBNP, age and diabetes were strongly associated with severity of diastolic dysfunction, whereas other HF risk factors and LVEF were not. More targeted surveillance using a combination of risk factors and biomarkers may improve identification of those at great risk of incident HF.

Objective The aim of the present study was to determine whether asymptomatic heart failure (HF) in the workplace is subject to the health worker effect, making screening using conventional risk factors combined with a cardiac biomarker, namely N-terminal pro B-type natriuretic peptide (NT-proBNP), as useful as in the general population. Methods Between June 2007 and December 2009 a ‘well’ population deemed at high risk for development of HF was identified through health insurance records. Blood was collected from volunteer participants for analysis of urea, electrolytes and creatinine, a full blood count and NT-proBNP. An echocardiogram was performed on selected participants based on high NT-proBNP concentrations. Results The mean left ventricular ejection fraction (LVEF) was significantly reduced in participants with the highest compared with the lowest NT-proBNP quintile. In multivariate analysis, log-transformed NT-proBNP was independently associated with impaired LVEF and with moderate to severe diastolic dysfunction after adjustment for age, sex, coronary artery disease, diabetes, hypertension and obesity. Conclusions A large burden of asymptomatic left ventricular dysfunction (AVLD) was observed in subjects aged 60 and over with plasma NT-proBNP in the top quintile that was independent of conventional risk factors and work status. HWE does not appear to operate in AVLD. NT-proBNP testing in a population with HF risk factors may cost-effectively identify those at greatest risk of developing HF in a working population and facilitate early diagnosis, treatment and maintenance of work capacity. What is known about the topic? Chronic heart failure (CHF) has several causes, the most common being hypertension and coronary ischaemia. CHF is a major health problem of increasing prevalence that severely impacts quality of life, shortens lives and reduces worker productivity. It is often not diagnosed early enough to take full advantage of ameliorating medication. What does this paper add? Population screening for CHF is not currently advocated. This may be because conventional risk factors must be used in combination and there is no useful biomarker available. Yet evidence (SOLVD (Studies of Left Ventricular Dysfunction trials) recommends early diagnosis. We believe the work place is an area of potential screening where there is little supporting evidence. This paper provides evidence that the biomarker NT-proBNP is a useful new tool that improves cost-effectiveness of screening in a selected population. Specifically, the paper recommends CHF screening in the population with the highest potential health gain (i.e. the working population) by the sector with the highest economic gain (i.e. employers). What are the implications for practitioners? The paper presents important health screening recommendations for medical and health and safety practitioners within a selected population of workers. We feel practitioners should consider screening for incipient heart failure, particularly within Australia’s working population, to save lives, provide economic benefit and extend working longevity.

Despite its long history, the renin-angiotensin system remains an active area of research. New components and interactions between novel and established components continue to be discovered. These developments are providing fresh insight into the role of the renin-angiotensin system in cardiovascular health and disease and new therapeutic targets for the prevention and treatment of cardiovascular disease. The pre-ISH 2012 satellite ‘Evolving concepts of the renin-angiotensin system’ provided a timely opportunity to review progress and to discuss the future of this exciting and productive area of research.

Background A significant proportion of individuals taking antihypertensive therapies fail to achieve blood pressures

Heart failure (HF) continues to grow as a cause of morbidity and mortality in our community and presents a significant public health problem, predominantly in individuals ≥65 years of age. Early intervention in asymptomatic HF subjects (Stage A/B) at risk of progression to symptomatic HF (Stage C/D) may provide an opportunity to halt this epidemic. The ability of cardiac imaging to assess cardiac structure and function permits early identification of those at increased risk of developing symptomatic HF. Systolic, diastolic, and structural left ventricular parameters each predict symptomatic HF, but no single parameter has sufficient sensitivity for screening to identify individuals with Stage A/B HF who are at increased risk of disease progression. Transthoracic echocardiography (TTE) has the advantage over other imaging modalities in being able to measure systolic, diastolic, and structural left ventricular parameters, and it identified at least 1 abnormal parameter in >50% of individuals with Stage A/B HF ≥65 years of age. Moreover, identification of at least 1 abnormality according to TTE in individuals with Stage A/B HF ≥65 years of age had 72% to 82% sensitivity for detection of those who subsequently developed symptomatic HF. Therefore, a case can be made for cardiac imaging by using TTE for community-dwelling populations with Stage A/B HF ≥65 years of age to identify those with increased risk of symptomatic HF who can be offered preventative therapies. Further studies are required to determine the best strategy for identifying the risk of symptomatic HF in younger individuals.

Background and Purpose— Several prospective studies have shown significant associations between plasma fibrinogen, viscosity, C-reactive protein (CRP), fibrin d -dimer, or tissue plasminogen activator (tPA) antigen and the risk of primary cardiovascular events. Little has been published on the associations of these variables with recurrent stroke. We studied such associations in a nested case-control study derived from the Perindopril Protection Against Recurrent Stroke Study (PROGRESS). Methods— Nested case-control study of ischemic (n=472) and hemorrhagic (n=83) strokes occurring during a randomized, placebo-controlled multicenter trial of perindopril-based therapy in 6105 patients with a history of stroke or transient ischemic attack. Controls were matched for age, treatment group, sex, region, and most recent qualifying event at entry to the parent trial. Results— Fibrinogen and CRP were associated with an increased risk of recurrent ischemic stroke after accounting for the matching variables and adjusting for systolic blood pressure, smoking, peripheral vascular disease, and statin and antiplatelet therapy. The odds ratio for the last compared with the first third of fibrinogen was 1.34 (95% CI, 1.01 to 1.78) and for CRP was 1.39 (95% CI, 1.05 to 1.85). After additional adjustment for each other, these 2 odds ratios stayed virtually unchanged. Plasma viscosity, tPA, and d -dimer showed no relationship with recurrent ischemic stroke, although tPA was significant for lacunar and large artery subtypes. Although each of these variables showed a negative relationship with recurrent hemorrhagic stroke, none of these relationships achieved statistical significance. Conclusions— Fibrinogen and CRP are risk predictors for ischemic but not hemorrhagic stroke, independent of potential confounders.

B-type natriuretic peptide (BNP) and C-reactive protein (CRP) are elevated in persons at risk for congestive heart failure (CHF). However, limited data are available directly comparing BNP-related peptides and CRP in persons at risk of CHF. To evaluate amino terminal–pro-BNP (NT-proBNP) and CRP, separately and together, for assessment of risk of CHF, we performed a nested case-control study of the 6105 participants of the Perindopril pROtection aGainst REcurrent Stroke Study (PROGRESS), a placebo-controlled study of a perindopril-based blood pressure–lowering regimen among individuals with previous stroke or transient ischemic attack (TIA). Each of 258 subjects who developed CHF resulting in death, hospitalization, or withdrawal of randomized therapy during a mean follow-up of 3.9 years was matched to 1 to 3 control subjects. NT-proBNP and CRP predicted CHF; the odds ratio for subjects in the highest compared with the lowest quarter was 4.5 (95% confidence interval, 2.7 to 7.5) for NT-proBNP and 2.9 (confidence interval, 1.9 to 4.7) for CRP, and each remained a predictor of CHF after adjustment for all other predictors. Screening for both markers provided better prognostic information than screening for either alone. Elevation of NT-proBNP above 50 pmol/L and CRP above 0.84 mg/L predicted CHF with sensitivity of 64% and specificity of 66%. NT-proBNP and CRP predicted CHF in subjects receiving perindopril-based therapy. We conclude that NT-proBNP and CRP are independent predictors of CHF risk after stroke or TIA. Moreover, NT-proBNP and CRP may be markers of mechanisms of CHF pathogenesis distinct from those responsive to angiotensin-converting enzyme inhibitor–based therapy.

OBJECTIVE: The plasma amino-terminal-pro-B-type natriuretic peptide (NT-proBNP) level predicted congestive heart failure, myocardial infarction, and ischaemic stroke in participants of the Perindopril Protection Against Recurrent Stroke Study (PROGRESS), a placebo-controlled study of the effects of blood pressure lowering on cardiovascular events among individuals with cerebrovascular disease. Active treatment comprised a flexible regimen based on perindopril, with the addition of indapamide at the discretion of treating physicians. Active treatment reduced cardiovascular events, and we therefore investigated whether active treatment modified NT-proBNP and other cardiovascular risk factors. METHODS: We measured NT-proBNP and other cardiovascular risk factors at randomization and after 13 months of therapy in a subset of 357 PROGRESS participants. RESULTS: Baseline systolic and pulse pressures were higher in individuals with elevated baseline NT-proBNP levels. In comparison with placebo, active treatment reduced the blood pressure and NT-proBNP levels, and increased renin levels. Reduction of NT-proBNP levels by active treatment was most evident in individuals with baseline NT-proBNP levels in the highest quarter (> 26 pmol/l), with a median reduction of 16 pmol/l (interquartile range 0-51 pmol/l, P = 0.004), corresponding to a median decrease of 39% (interquartile range 0-69%). Active treatment reduced blood pressure similarly for individuals in each of the four quarters of baseline NT-proBNP. Active therapy had no effect on plasma lipid, C-reactive protein, homocysteine, or soluble vascular cell adhesion molecule 1 levels. CONCLUSION: We conclude that plasma NT-proBNP level, in addition to predicting cardiovascular risk, may provide a measure of risk reduction by blood pressure-lowering therapy.

Baudrand et al1 reported that statin use was associated with lower plasma aldosterone levels and urinary aldosterone excretion in nonrandomized studies of hypertensive and diabetic subjects, both in the basal state and during stimulation by angiotensin II infusion or by a low sodium diet. They also reported that 10 μmol/L statins, a concentration that far exceeds peak plasma statin concentrations in patients, reduced the aldosterone secretory response of rat zona glomerulosa cells to angiotensin II and to potassium stimulation in vitro, and proposed that statins might reduce plasma aldosterone levels …

BACKGROUND: Bleeding into the chest is a life-threatening complication of cardiac surgery. Blood transfusion has been implicated as an important cause of harm associated with bleeding, based largely on studies demonstrating an independent association between transfusion and mortality. These studies did not, however, consider the possibility that bleeding may in itself be harmful, inasmuch as drains are inefficient at clearing blood from the chest and retained blood may compromise cardiac and lung function. STUDY DESIGN AND METHODS: We undertook a multivariate logistic regression analysis of the risk factors associated with mortality in 2599 consecutive patients undergoing cardiac surgery. Unlike previous studies the risk factors examined included the volume of chest tube drainage at 24 hours. A stratified analysis was also undertaken that compared the adjusted risk of death for patients exposed or not exposed to a postoperative blood transfusion. RESULTS: Blood transfusion was not an independent predictor of mortality (p = 0.4). Chest tube drainage was the strongest independent predictor of mortality (p

1. Aliskiren is a renin inhibitor with an IC(50) of 0.6 nmol/L for human renin, 4.5 nmol/L for mouse renin and 80 nmol/L for rat renin. 2. In the present study, we compared the effects of aliskiren (10 mg/kg per day), the angiotensin-converting enzyme inhibitor perindopril (0.2 mg/kg per day) and their combination on angiotensin and bradykinin peptides in female heterozygous (mRen-2)27 rats, transgenic for the mouse renin gene. 3. All three treatments produced similar reductions in systolic blood pressure, heart weight and plasma aldosterone levels and reduced angiotensin II levels in lung, but only perindopril and the combination reduced angiotensin II levels in kidney of (mRen-2)27 rats. In contrast, aliskiren and the combination, but not perindopril alone, increased cardiac bradykinin levels. Aliskiren increased immunostaining for tissue kallikrein in the heart and reduced cardiac fibrosis. 4. We investigated the mechanism underlying the increase in bradykinin levels following aliskiren treatment in Sprague-Dawley rats, in which aliskiren has a lower potency for renin inhibition. Aliskiren (10 mg/kg per day) reduced renal angiotensin levels within 24 h, but treatment for > 24 h was required to increase cardiac bradykinin levels. Moreover, 3 mg/kg per day aliskiren increased cardiac bradykinin levels, but did not reduce renal angiotensin levels. Aliskiren did not potentiate the hypotensive effects of bradykinin; however, it increased tissue kallikrein, but not plasma kallikrein, mRNA levels in the heart. 5. These data demonstrate that the aliskiren-induced increase in cardiac bradykinin levels is independent of renin inhibition and changes in bradykinin metabolism, but is associated with increased tissue kallikrein gene expression.

We examined whether the renin inhibitor, aliskiren, provides similar or greater protection than ACE inhibition from non-proliferative diabetic retinopathy and from the proliferative neoangiogenesis of oxygen-induced retinopathy.Transgenic (mRen-2)27 rats, which overexpress mouse renin and angiotensin in extra-renal tissues, were studied. For diabetic studies, non-diabetic, diabetic (streptozotocin, 55 mg/kg), diabetic + aliskiren (10 mg kg(-1) day(-1), pump), or diabetic + lisinopril (10 mg kg(-1) day(-1), drinking water) rats were evaluated over 16 weeks. For oxygen-induced retinopathy studies, rats were exposed to 80% oxygen (22 h/day) from postnatal days 0 to 11, and then room air from postnatal days 12 to 18. Aliskiren (10 or 30 mg kg(-1) day(-1), pump) or lisinopril (10 mg kg(-1) day(-1), drinking water) was administered during retinopathy development between postnatal days 12 and 18.Systolic BP in diabetic (mRen-2)27 rats was reduced with 10 mg kg(-1) day(-1) aliskiren, but only lisinopril normalised systolic blood pressure. In diabetic (mRen-2)27 rats, 10 mg kg(-1) day(-1) aliskiren and lisinopril reduced retinal acellular capillaries and leucostasis to non-diabetic levels. In oxygen-induced retinopathy, neoangiogenesis and retinal inflammation (leucostasis, ED-1 immunolabelling) were partially reduced by 10 mg kg(-1) day(-1) aliskiren and normalised by 30 mg kg(-1) day(-1) aliskiren, whereas lisinopril normalised neoangiogenesis and reduced leucostasis and ED-1 immunolabelling. Aliskiren and lisinopril normalised retinal vascular endothelial growth factor expression; however, only aliskiren reduced intercellular adhesion molecule-1 to control levels.Aliskiren provided similar or greater retinal protection than ACE inhibition and may be a potential treatment for diabetic retinopathy.

The (pro)renin receptor [(P)RR] is implicated in organ pathology. We examined the cellular location of the (P)RR and whether a putative (P)RR antagonist, RILLKKMPSV, corresponding to the handle region of the prorenin prosegment (handle region peptide [HRP]) influences angiogenesis, inflammation, and neuronal and glial function in rat retina. The (P)RR was localized to retinal vessels, endothelial cells, and pericytes, but most immunolabeling was in ganglion cells and glia. HRP (1 mg/kg per day by IP injection) reduced physiological angiogenesis in developing retina. Moreover, HRP (0.1 mg/kg per day by subcutaneous minipump) reduced pathological retinal angiogenesis, inflammation, and vascular endothelial growth factor and intercellular adhesion molecule-1 mRNA in rats with oxygen-induced retinopathy (OIR) to an extent similar to valsartan (10 mg/kg per day, IP). In contrast to its effects on vasculature, HRP compromised the electroretinogram in shams and OIR and increased phosphorylated extracellular-signal–related protein kinase 1/2 immunolabeling in shams but not in OIR, whereas valsartan did not affect the electroretinogram and reduced extracellular-signal–related protein kinase 1/2 immunolabeling in OIR. Retinal (P)RR mRNA levels were increased in OIR; HRP, but not valsartan, increased (P)RR mRNA levels in shams, whereas both HRP and valsartan reduced (P)RR mRNA levels in OIR. A control peptide (VSPMKKLLIR, 0.1 mg/kg per day) did not influence retinal vasculopathy or function. Circulating HRP levels in rats administered 1 mg/kg per day HRP were undetectable (

We measured components of the kallikrein- kinin system in human type 2 diabetes mellitus and the effects of statin therapy on the circulating kallikrein-kinin system.Circulating levels of bradykinin and kallidin peptides, and high and low molecular weight kininogens, as well as plasma and tissue kallikrein, and kallistatin were measured in non-diabetic and diabetic patients before coronary artery bypass graft surgery. Tissue kallikrein levels in atrial tissue were examined by immunohistochemistry and atrial tissue kallikrein mRNA quantified.Plasma levels of tissue kallikrein were approximately 62% higher in diabetic than in non-diabetic patients (p=0.001), whereas no differences were seen in circulating levels of bradykinin and kallidin peptides, and high and low molecular weight kininogens, or in plasma kallikrein or kallistatin. Immunohistochemistry revealed a twofold increase in tissue kallikrein levels in atrial myocytes (p= 0.015), while tissue kallikrein mRNA levels were increased eightfold in atrial tissue of diabetic patients (p=0.014). Statin therapy did not change any variables of the circulating kallikrein-kinin system. Neither aspirin, calcium antagonists, beta blockers or long-acting nitrate therapies influenced any kallikrein-kinin system variable.Tissue kallikrein levels are increased in type 2 diabetes, whereas statin therapy does not modify the circulating kallikrein-kinin system. Cardiac tissue kallikrein may play a greater cardioprotective role in type 2 diabetic than in non-diabetic patients and contribute to the benefits of ACE inhibitor therapy in type 2 diabetic patients. However, our findings do not support a role for the kallikrein-kinin system in mediating the effects of statin therapy on endothelial function.

Over many decades, several attempts have been made to treat hypertension using a vaccination strategy to inhibit the renin-angiotensin system. Renin vaccination successfully inhibited renin activity and reduced blood pressure in animal models, but caused autoimmune disease of the kidney. By contrast, most previous studies of angiotensin vaccination failed to reduce blood pressure in animal models, despite producing high titers of antibodies that prevented the pressor response to exogenous angiotensins. Angiotensin vaccination is being revisited as a strategy for treating hypertension, in the hope that new conjugates of angiotensin I and angiotensin II will produce antibodies of sufficient titer and affinity to reduce blood pressure in patients with hypertension. A recent clinical study of angiotensin II vaccination provided some cause for optimism, but many hurdles remain before this strategy can compete with current oral medications for hypertension.

Background: Measurement of plasma renin is important for the clinical assessment of hypertensive patients. The most common methods for measuring plasma renin are the plasma renin activity (PRA) assay and the renin immunoassay. The clinical application of renin inhibitor therapy has thrown into focus the differences in information provided by activity assays and immunoassays for renin and prorenin measurement and has drawn attention to the need for precautions to ensure their accurate measurement.Content: Renin activity assays and immunoassays provide related but different information. Whereas activity assays measure only active renin, immunoassays measure both active and inhibited renin. Particular care must be taken in the collection and processing of blood samples and in the performance of these assays to avoid errors in renin measurement. Both activity assays and immunoassays are susceptible to renin overestimation due to prorenin activation. In addition, activity assays performed with peptidase inhibitors may overestimate the degree of inhibition of PRA by renin inhibitor therapy. Moreover, immunoassays may overestimate the reactive increase in plasma renin concentration in response to renin inhibitor therapy, owing to the inhibitor promoting conversion of prorenin to an open conformation that is recognized by renin immunoassays.Conclusions: The successful application of renin assays to patient care requires that the clinician and the clinical chemist understand the information provided by these assays and of the precautions necessary to ensure their accuracy.

Angiotensin-converting enzyme (ACE) plays a central role in the production of the vasoconstrictor angiotensin II. ACE is a single polypeptide, but it contains 2 homologous and independent catalytic domains, each of which binds zinc. To understand the in vivo role of these 2 domains, we used gene targeting to create mice with point mutations in the ACE C-domain zinc-binding motif. Such mice, termed ACE13/13, produce a full-length ACE protein with tissue expression identical to wild-type mice. Analysis of ACE13/13 mice showed that they produce ACE having only N-domain catalytic activity, as determined by the hydrolysis of domain specific substrates and by chloride sensitivity. ACE13/13 mice have blood pressure and blood angiotensin II levels similar to wild-type mice. However, plasma renin concentration is increased 2.6-fold and blood angiotensin I levels are increased 7.5-fold. Bradykinin peptide levels are not different from wild-type levels. ACE13/13 mice have a reduced increase of blood pressure after intravenous infusion of angiotensin I. ACE13/13 mice have a normal renal structure, but they are not able to concentrate urine after dehydration as effectively as wild-type mice. This study shows that the C-domain of ACE is the predominant site of angiotensin I cleavage in vivo. Although mice lacking C-domain activity have normal physiology under laboratory conditions, they respond less well to the stress of dehydration.

In the heart, angiotensin II has been suggested to regulate cardiac remodeling and promote cardiac hypertrophy. To examine this, we studied compound heterozygous mice, called angiotensin-converting enzyme (ACE) 1/8, in which one ACE allele is null, whereas the other ACE allele (the 8 allele) targets expression to the heart. In this model, cardiac ACE levels are about 15 times those of wild-type mice, and ACE expression is reduced or eliminated in other tissues. ACE 1/8 mice have 58% the cardiac ACE of a previous model, called ACE 8/8, but both ACE 1/8 and ACE 8/8 mice have ventricular angiotensin II levels about twofold those of wild-type controls. Despite equivalent levels of cardiac angiotensin II, ACE 1/8 mice do not develop the marked atrial enlargement or the conduction defects previously reported in the ACE 8/8 mice. Six-month-old ACE 1/8 mice have normal cardiac function, as determined by echocardiography and left ventricular catheterization, despite the elevated levels of angiotensin II. ACE 1/8 mice also have normal levels of connexin 43. Both wild-type and ACE 1/8 mice develop similar degrees of cardiac hypertrophy after aortic banding. These data suggest that a moderate increase of local angiotensin II production in the heart does not produce cardiac dysfunction, at least under basal conditions, and that, in response to aortic banding, cardiac hypertrophy is not augmented by a twofold increase of cardiac angiotensin II.

Aliskiren (Tekturna or Rasilez) is an orally active renin inhibitor approved for the treatment of hypertension.1 As with inhibition of the renin-angiotensin system by angiotensin-converting enzyme inhibitors or type 1 angiotensin II (Ang II) receptor blockers, aliskiren therapy is accompanied by a reactive rise in plasma renin concentration, although in contrast to angiotensin-converting enzyme inhibitor and angiotensin receptor blocker therapy, aliskiren reduces enzymatic plasma renin activity (PRA). A direct comparison of aliskiren and angiotensin receptor blocker therapies in hypertensive patients showed differences in the magnitude of the reactive renin response.2,3 In 1 study, 300 mg/d of aliskiren and 320 mg/d of valsartan were similarly hypotensive, whereas plasma renin concentration was 2-fold higher during aliskiren therapy.3 In a second study, 150 mg/d of aliskiren and 150 mg/d of irbesartan were similarly hypotensive, whereas plasma renin concentration was 1.4-fold higher during aliskiren therapy.2,4 Moreover, the renin response to 300 mg of aliskiren was 1.6-fold higher than the response to 320 mg of valsartan in sodium-replete normotensive volunteers.5 Sealey and Laragh6 proposed that the exaggerated renin response may limit aliskiren’s ability to reduce blood pressure by counteracting the effect of renin inhibition on Ang II levels and may thereby account for the failure of 600 mg of aliskiren to reduce blood pressure at >300 mg of aliskiren. They also proposed the renin response to aliskiren therapy may paradoxically increase blood pressure in patients with a highly reactive renin concentration (renovascular, advanced, and malignant hypertension).6 Another concern expressed by several authors was the possible action of the increased renin concentrations on the putative renin receptor.2,7–10 How should the exaggerated renin response to aliskiren therapy be interpreted? Renin secretion is subject to tonic negative feedback inhibition by Ang II, and the reactive increase in renin concentration provides …

The report by Mohammed et al1 is a valuable description of myocardial pathology in terminal heart failure with preserved ejection fraction (HFpEF). The authors describe lower coronary microvascular density and greater myocardial fibrosis in HFpEF patients than in controls, and note that myocardial fibrosis was inversely associated with microvascular density in both HFpEF patients and controls. Moreover, they suggest that reduced microvascular density may contribute to myocardial fibrosis, and that both …

Duncan J CampbellSt. Vincent’s Institute of Medical Research and the Department of Medicine, University of Melbourne, St. Vincent’s Hospital, Fitzroy, Victoria, AustraliaBackground: Angiotensin-converting enzyme inhibitors (ACEI) have a well-established role in the prevention of cardiovascular events in hypertension, left ventricular dysfunction, and heart failure. More recently, ACEI have been shown to prevent cardiovascular events in individuals with increased cardiovascular risk, where hypertension, left ventricular dysfunction, or heart failure was not the primary indication for ACEI therapy.Objective: To review studies of the effects of the ACEI perindopril on cardiovascular events.Method: The EUROPA (European Trial on Reduction of Cardiac Events with Perindopril in Patients with Stable Coronary Artery Disease Study), PROGRESS (Perindopril Protection Against Recurrent Stroke Study), and ASCOT-BPLA (Anglo-Scandinavian Cardiac Outcomes Trial – Blood Pressure Lowering Arm) trials are reviewed.Results: Perindopril alone reduced cardiovascular events in subjects with stable coronary heart disease. Perindopril in combination with indapamide reduced cardiovascular events in subjects with cerebrovascular disease. Perindopril in combination with amlodipine reduced cardiovascular events in subjects with hypertension.Conclusion: Perindopril reduced cardiovascular events. The reduction of cardiovascular events by perindopril was in large part associated with reduction of blood pressure, and greater reduction in cardiovascular events was associated with greater reduction of blood pressure. Perindopril may need to be combined with other antihypertensive agents to maximize reduction of cardiovascular events.Keywords: Angiotensin-converting enzyme inhibitor, hypertension, coronary heart disease, stroke, myocardial infarction, heart failure

It has long been proposed that the renin-angiotensin system exerts a stimulatory influence on the sympathetic nervous system, including augmentation of central sympathetic outflow and presynaptic facilitation of norepinephrine release from sympathetic nerves. We tested this proposition in 19 patients with essential hypertension, evaluating whether the angiotensin receptor blockers (ARBs) eprosartan and losartan had identifiable antiadrenergic properties. This was done in a prospective, randomized, three-way placebo-controlled study of crossover design. Patients were randomized to 600 mg of eprosartan daily, 50 mg of losartan daily, or placebo. The treatment period was 4 wk, with 2-wk washout periods. Multiunit firing rates in efferent sympathetic nerves distributed to skeletal muscle vasculature (muscle sympathetic nerve activity, MSNA) were measured with microneurography, testing whether ARBs inhibit central sympathetic outflow. In parallel, isotope dilution methodology was used to measure whole body norepinephrine spillover to plasma. Mean blood pressure on placebo was 151/98 mmHg, with both ARBs causing reductions of approximately 11 mmHg systolic and 6 mmHg diastolic pressure, placebo corrected. Both MSNA [35 +/- 12 bursts/min (mean +/- SD) on placebo] and whole body norepinephrine spillover [366 +/- 247 ng/min] were unchanged by ARB administration, indicating that the ARBs did not materially inhibit central sympathetic outflow or act presynaptically to reduce norepinephrine release at existing rates of nerve firing. These findings contrast with the easily demonstrable reduction in sympathetic nervous activity produced by antihypertensive drugs of the imidazoline-binding class, which are known to act within the brain to inhibit sympathetic nervous outflow. We conclude that sympathetic nervous inhibition is not a major component of the blood pressure-lowering action of ARBs in essential hypertension.

BACKGROUND Angiotensin (Ang) II may enhance the influence of the sympathetic nervous system at various levels by facilitating norepinephrine (NE) release. We investigated whether such an interaction is evident in the human heart and whether it has an impact on left ventricular (LV) structure. METHODS AND RESULTS Ang I and Ang II concentrations were determined in arterial and coronary sinus (CS) plasma samples in a group of normotensive (n = 10) and hypertensive (n = 18) subjects. Total systemic and cardiac NE spillover was measured using isotope dilution methodology and LV structure by echocardiography. Arterial and CS concentrations of Ang I and Ang II were similar in both groups (Ang II CS, 5.8 +/- 4.0 versus 3.7 +/- 3.1 fmol/ml; P = not significant), as was the Ang II/Ang I ratio (CS, 0.56 +/- 0.17 versus 0.54 +/- 0.22 fmol/fmol; P = not significant). Total systemic (223 +/- 145 versus 374 +/- 149 ng/min; P < 0.05) and cardiac NE spillover (11.7 +/- 6.3 versus 19.4 +/- 10.5 ng/min; P < 0.05) were increased in hypertensive patients, as was LV mass index (LVMI) (86.7 +/- 14.7 versus 117.2 +/- 19.4 g/m; P < 0.001). LVMI correlated with cardiac NE spillover (r = 0.47; P < 0.02). No correlation was evident between CS Ang II and cardiac NE spillover (r = 0.001; P = not significant) or LVMI (r = -0.20; P = not significant). Arterial Ang II tended to correlate with total systemic NE spillover (r = 0.34; P = 0.081). When hypertensive subjects were divided into two groups with either high or low CS Ang II concentration, cardiac NE spillover and LVMI did not differ between the two groups. CONCLUSION These findings suggest a growth-promoting effect of increased cardiac sympathetic tone on cardiomyocytes in hypertensive patients, but do not support the notion of a significant role of Ang II for norepinephrine release and LV hypertrophy in the hypertensive human heart.

Obesity in humans is associated with lipid accumulation in skeletal muscle, insulin and leptin resistance, and type 2 diabetes. AMP-activated protein kinase (AMPK) is an important regulator of fatty acid (FA) metabolism in skeletal muscle. To address the hypothesis that lipid accumulation in skeletal muscle of obese subjects may be due to down-regulation of AMPK, we measured mRNA and protein levels of AMPK isoforms, AMPK1 and -2 activity, AMPK kinase activity, acetylcoenzyme A carboxylase (ACC) expression and phosphorylation, and FA metabolism in biopsies of rectus abdominus muscle from lean and obese women. We also examined the effect of 5-aminoimidazole-4-carboxamide riboside (AICAR) on AMPK activity and the effects of AICAR and leptin on FA metabolism. Skeletal muscle of obese subjects had increased total FA uptake and triglyceride esterification, and leptin failed to stimulate FA oxidation. However, AMPK mRNA and protein expression, AMPK1 and -2 activities, AMPK kinase activity, ACC phosphorylation, and FA oxidation were similar in lean and obese subjects. Moreover, AICAR increased AMPK2 activity, ACC phosphorylation, and palmitate oxidation to a similar degree in muscle from lean and obese subjects. We conclude that the abnormal lipid metabolism and leptin resistance of skeletal muscle of obese subjects is not due to down-regulation of AMPK. In addition, the similar stimulation by AICAR of AMPK in skeletal muscle of lean and obese subjects suggests that direct pharmacological activation of AMPK may be a therapeutic approach for stimulating FA oxidation in the treatment of human obesity. (J Clin Endocrinol Metab 89: 4575– 4580, 2004)

There is uncertainty about the contribution of angiotensin-converting enzyme (ACE) to angiotensin II formation, with recent studies suggesting that non-ACE enzymes may be the predominant pathway of angiotensin II formation in kidney, heart, and lung. To investigate the role of ACE in angiotensin II formation, we measured angiotensin I and II levels in blood, kidney, and heart of 2 mouse genetic models (ACE.1 and ACE.4) of reduced somatic ACE gene expression and in blood, kidney, heart, lung, adrenal, and brain of mice administered the ACE inhibitor lisinopril. We also measured the levels of bradykinin (1-9) and its ACE metabolite bradykinin (1-7). Reduced ACE gene expression and ACE inhibition had similar effects on angiotensin and bradykinin peptide levels. Angiotensin II levels were reduced by 70% to 97% in blood, 92% to 99% in kidney, 93% to 99% in heart, 97% in lung, and 85% in adrenal and brain. The marked reductions in angiotensin II/angiotensin I ratio indicated that ACE was responsible for at least 90% of angiotensin I conversion to angiotensin II in blood, kidney, heart, lung, and brain, and at least 77% in adrenal. Blood bradykinin (1-9) levels were increased 6.4-fold to 8.4-fold. Heart bradykinin (1-9) levels were increased in ACE.4 mice and the bradykinin (1-7)/bradykinin (1-9) ratio was reduced in kidney and heart of ACE.4 mice and heart of lisinopril-treated mice. These studies demonstrate that ACE is the predominant pathway of angiotensin II formation in blood and tissues of mice and plays a major role in bradykinin (1-9) metabolism in blood and, to a lesser extent, in kidney and heart.

There is growing evidence that essential hypertension is commonly neurogenic and is initiated and sustained by sympathetic nervous system overactivity. Potential mechanisms include increased central sympathetic outflow, altered norepinephrine (NE) neuronal reuptake, diminished arterial baroreflex dampening of sympathetic nerve traffic, and sympathetic neuromodulation by angiotensin II. To address this issue, we used microneurography and radiotracer dilution methodology to measure regional sympathetic activity in 22 hypertensive patients and 11 normotensive control subjects. The NE transport inhibitor desipramine was infused to directly assess the potential role of impaired neuronal NE reuptake. To evaluate possible angiotensin sympathetic neuromodulation, the relation of arterial and coronary sinus plasma concentrations of angiotensin II to sympathetic activity was investigated. Hypertensive patients displayed increased muscle sympathetic nerve activity and elevated total systemic, cardiac, and renal NE spillover. Cardiac neuronal NE reuptake was decreased in hypertensive subjects. In response to desipramine, both the reduction of fractional transcardiac 3 [H]NE extraction and the increase in cardiac NE spillover were less pronounced in hypertensive patients. DNA sequencing analysis of the NE transporter gene revealed no mutations that could account for reduced transporter activity. Arterial baroreflex control of sympathetic nerve traffic was not diminished in hypertensive subjects. Angiotensin II plasma concentrations were similar in both groups and were not related to indexes of sympathetic activation. Increased rates of sympathetic nerve firing and reduced neuronal NE reuptake both contribute to sympathetic activation in hypertension, whereas a role for dampened arterial baroreflex restraint on sympathetic nerve traffic and a peripheral neuromodulating influence of angiotensin II appear to be excluded.

The renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS) each encompasses a large number of molecules, with several participating in both systems. The RAS generates a family of bioactive angiotensin peptides with varying biological activities. These include angiotensin-(1-8) (Ang II), angiotensin-(2-8) (Ang III), angiotensin-(3-8) (Ang IV), and angiotensin-(1-7) [Ang-(1-7)]. Ang II and Ang III act on type 1 (AT(1)) and type 2 (AT(2)) angiotensin receptors, whereas, Ang IV and Ang-(1-7) act on their own receptors. The KKS also generates a family of bioactive peptides with varying biological activities. These include hydroxylated and non-hydroxylated bradykinin and kallidin peptides and their carboxypeptidase metabolites des-Arg(9)-bradykinin and des-Arg(10)-kallidin. Whereas bradykinin and kallidin act mainly via the type 2 bradykinin (B(2)) receptor, des-Arg(9)-bradykinin and des-Arg(10)-kallidin act mainly via the type 1 bradykinin (B(1)) receptor. The AT(1) receptor forms heterodimers with the AT(2) and B(2) receptors and there is cross talk between the AT(1) and epidermal growth factor receptors. The B(2) receptor also interacts with angiotensin converting enzyme and nitric oxide synthase. Both angiotensin and kinin peptides are metabolised by many different peptidases that are important determinants of the activities of the RAS and KKS, and several of which participate in both systems.

To investigate the pathophysiology underlying raised lactate levels after cardiac surgery with cardiopulmonary bypass (CPB).Prospective observational study.Medical and surgical intensive care unit of a tertiary hospital.A total of 40 patients undergoing first-time coronary artery bypass grafting with CPB.The prothrombotic response to cardiac surgery with CPB was assessed by measuring plasma levels of prothrombin fragment 1 + 2 and plasminogen activator inhibitor (PAI) activity. The hemodynamic responses to cardiac surgery with CPB were also measured using standard techniques.After cardiac surgery, prothrombin fragment 1 + 2 levels increased 6-fold and PAI activity increase 2- to 3-fold (p.0001). Lactate levels were not associated with prothrombin fragment 1 + 2 and PAI activity levels after CPB. Lactate levels were associated with baseline PAI activity (p =.006), a history of hypertension (p =.02), raised baseline lactate levels (p =.02), an early increase in body temperature after CPB (p =.05), a late increase in oxygen consumption after CPB (p =.03), and a raised white cell count after CPB (p =.06). Lactate levels were inversely associated with the maximum activated clotting time level reached during CPB (p =.02). Multivariate linear regression demonstrated lactate levels were independently associated with baseline PAI activity.We found cardiac surgery with CPB was associated with a marked prothrombotic response. Lactate levels were associated with elevated baseline PAI activity and evidence of an amplified inflammatory response to cardiac surgery with CPB. Our findings implicate aspects of the inflammatory response, including microvascular thrombosis, in the development of raised lactate levels after cardiac surgery with CPB.

The enormous benefits of inhibition of ACE demonstrate that manipulation of the metabolism of peptide hormones is a valuable therapeutic strategy for cardiovascular disease. Recent attempts to expand these benefits have combined ACE inhibition with inhibition of other peptidases such as neutral endopeptidase (NEP) in a single molecule, a strategy known as vasopeptidase inhibition. NEP metabolizes natriuretic peptides, and NEP inhibition offers the prospect of combining the benefits of increased natriuretic peptide levels with those of ACE inhibition. However, peptidases such as ACE and NEP have many different substrates, and there are complex interactions between ACE inhibition and NEP inhibition. Both ACE and NEP metabolize the kinin peptides bradykinin and kallidin, and NEP also converts angiotensin (Ang) I to Ang-(1-7) and metabolizes Ang II and endothelin. Addition of NEP inhibition to ACE inhibition potentiates the ACE inhibitor–induced increase in kinin levels, increases Ang II levels, reduces Ang-(1-7) levels, and may increase endothelin levels. These additional consequences of combined ACE/NEP inhibition increase the risk of angioedema and may counteract any benefit of ACE inhibition that depends on reduced Ang II levels and increased Ang-(1-7) levels. Further considerations are that the ratio of ACE and NEP inhibition is fixed for vasopeptidase inhibitors, and there is uncertainty how these drugs should be compared with ACE inhibitors. Vasopeptidase inhibitors will therefore require careful evaluation before they are introduced to patient care.

Objective - The reported association between calibrated integrated backscatter (cIB) and myocardial fibrosis is based on study of patients with dilated or hypertrophic cardiomyopathy and extensive (mean 15–34%) fibrosis. Its association with lesser degrees of fibrosis is unknown. We examined the relationship between cIB and myocardial fibrosis in patients with coronary artery disease.Methods - Myocardial histology was examined in left ventricular epicardial biopsies from 40 patients (29 men and 11 women) undergoing coronary artery bypass graft surgery, who had preoperative echocardiography with cIB measurement.Results - Total fibrosis (picrosirius red staining) varied from 0.7% to 4%, and in contrast to previous reports, cIB showed weak inverse associations with total fibrosis (r=−0.32, p=0.047) and interstitial fibrosis (r=−0.34, p=0.03). However, cIB was not significantly associated with other histological parameters, including immunostaining for collagens I and III, the advanced glycation end product (AGE) Nε-(carboxymethyl)lysine (CML) and the receptor for AGEs (RAGE). When biomarkers were examined, cIB was weakly associated with log plasma levels of amino-terminal pro-B-type natriuretic peptide (r=0.34, p=0.03), creatinine (r=0.33, p=0.04) and glomerular filtration rate (r=−0.33, p=0.04), and was more strongly associated with log plasma levels of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) (r=0.44, p=0.01) and soluble RAGE (r=0.53, p=0.002).Conclusions - Higher cIB was not a marker of increased myocardial fibrosis in patients with coronary artery disease, but was associated with higher plasma levels of sVEGFR-1 and soluble RAGE. The role of cIB as a non-invasive index of fibrosis in clinical studies of patients without extensive fibrosis is, therefore, questionable.