Serum uric acid and its relationship with metabolic syndrome and cardiovascular risk profile in patients with hypertension: insights from the I-DEMAND study.

BACKGROUND AND AIMS: The independent role of serum uric acid (SUA) as a marker of cardio-renal risk is debated. The aim of this study was to assess the relationship between SUA, metabolic syndrome (MS), and other cardiovascular (CV) risk factors in an Italian population of hypertensive patients with a high prevalence of diabetes. METHODS AND RESULTS: A total of 2429 patients (mean age 62 ± 11 years) among those enrolled in the I-DEMAND study were stratified on the basis of SUA gender specific quartiles. MS was defined according to the NCEP-ATP III criteria, chronic kidney disease (CKD) as an estimated GFR (CKD-Epi) <60 ml/min/1.73 m(2) or as the presence of microalbuminuria (albumin-to-creatinine ratio ≥2.5 mg/mmol in men and ≥3.5 mg/mmol in women). The prevalence of MS, CKD, and positive history for CV events was 72%, 43%, and 20%, respectively. SUA levels correlated with the presence of MS, its components, signs of renal damage and worse CV risk profile. Multivariate logistic regression analysis revealed that SUA was associated with a positive history of CV events and high Framingham risk score even after adjusting for MS and its components (OR 1.10, 95% CI 1.03-1.18; P = 0.0060; OR 1.28, 95% CI 1.15-1.42; P < 0.0001). These associations were stronger in patients without diabetes and with normal renal function. CONCLUSIONS: Mild hyperuricemia is a strong, independent marker of MS and high cardio-renal risk profile in hypertensive patients under specialist care. Intervention trials are needed to investigate whether the reduction of SUA levels favorably impacts outcome in patients at high CV risk.

Glycaemic fall after a glucose load. A population-based study.

BACKGROUND AND AIMS: A blood glucose (BG) fall after an oral glucose load has never been described previously at a population level. This study was aimed at looking for a plasma glucose trend after an oral glucose load for possible blood glucose fall if any, and for its impact on coronary mortality at a population level. METHODS AND RESULTS: In subjects from an unselected general population, BG and insulin were detected before and 1 and 2h after a 75-g oral glucose load for insulin sensitivity and ß-cell function determination. Blood pressure, blood examinations and left ventricular mass were measured, and mortality was monitored for 18.8±7.7 years. According to discriminant analysis, the population was stratified into cluster 0 (1-h BG < fasting BG; n=497) and cluster 1 (1-h BG ≥ fasting BG; n=1733). To avoid any interference of age and sex, statistical analysis was limited to two age-gender-matched cohorts of 490 subjects from each cluster (n=940). Subjects in cluster 0 showed significantly higher insulin sensitivity and ß-cell function, lower visceral adiposity and lower blood pressure values. Adjusted coronary mortality was 8 times lower in cluster 0 than 1 (p<0.001). The relative risk of belonging to cluster 1 was 5.40 (95% CI 2.22-13.1). CONCLUSION: It seems that two clusters exist in the general population with respect to their response to an oral glucose load, independent of age and gender. Subjects who respond with a BG decrease could represent a privileged sub-population, where insulin sensitivity and ß-cell function are better, some risk factors are less prevalent, and coronary mortality is lower.

Oxidative stress-related proteins in a Conn's adenoma tissue. Relevance for aldosterone's prooxidative and proinflammatory activity.

BACKGROUND AND AIM: Angiotensin II (Ang II) induces oxidative stress (OxSt), which is essential for cardiovascular remodeling. Aldosterone also induces fibrosis and remodeling through direct effect on non-classical mineralocorticoid (MR) target tissues. However, studies on the role of aldosterone on OxSt and related factors in humans are lacking. MATERIALS AND METHODS: We assessed gene and protein expression of p22phox (RT-PCR and Western blot), NAD(P)H oxidase subunit essential for superoxide production and gene expression of transforming growth fator (TGF) beta, plasminogen activator inhibitor (PAI)-1, and heme oxygenase (HO)-1, effectors of OxSt (RT-PCR), in a Conn's adenoma, removed from a patient with primary hyperaldosteronism. Ang II type 1 (AT1R) and MR receptors expression were also evaluated (RT-PCR). The normal adrenal tissue adjacent to the adenoma was used as control. RESULTS: p22phox gene and protein expression were higher (31% and 53%, respectively) in the adrenal adenoma. TGFbeta, PAI-1, and HO-1 gene expression were also higher (25%, 129%, and 25%, respectively) in the adrenal adenoma while AT1R gene expression was similar (8%). The expression of MR in the adenoma was documented. CONCLUSIONS: This report demonstrates in a human model that the increased aldosterone production has effects on enzyme systems related to OxSt, enhancing the systemic fibrogenic effects of aldosterone excess through TGFbeta and PAI-1 expression which was previously demonstrated only indirectly in vitro and in animal models. The presence of MR expression in the adenoma may link the hormone with the adenoma growth. Therefore, the results of this study derived from a single case might represent an important working hypothesis for further research in a larger number of cases to clarify the role of aldosterone overproduction on OxSt and its clinical relevance.

High angiotensin II state without cardiac remodeling (Bartter's and Gitelman's syndromes): are angiotensin II type 2 receptors involved?

BACKGROUND/AIMS: While Angiotensin II (Ang II) is a major factor in the development of cardiomyocyte hypertrophy and a pivotal role for Ang II signals via ERK1/2 has been identified, mechanism(s) responsible are still unclear. As Bartter's and Gitelman's syndrome patients (BS/GS) have increased Ang II, and yet normo/hypotension, hyporesponsiveness to pressors and blunted Ang II signaling via type 1 receptors (AT1R), this study assesses BS/GS's left ventricular (LV) mass and structure as well as Ang II induced ERK1/2 phosphorylation compared with essential hypertensive patients (EH) and normotensive healthy subjects (C) to gain insight into Ang II mediated processes. METHODS: Indices of cardiac hypertrophy were determined by M-mode, two-dimensional echo Doppler and ERK phosphorylation by Western blot. RESULTS: None of BS/GS exhibited LV remodelling; LV mass, LV end-diastolic volume and mass/volume ratio were unchanged vs C (60+/-14 g/m2 vs 64+/-12, 64+/-12 ml/m2 vs 60+/-8 and 0.95+/-0.2 vs 1.0+/-0.2, respectively) and reduced vs EH (119+/-15, p<0.001, 78+/-9, p<0.05 and 1.52+/-0.15, p<0.01). Despite BS/GS's higher plasma renin activity and aldosterone and unchanged level of AT1R, Ang II induced ERK1/2 phosphorylation was reduced vs both C and EH: 0.64 d.u.+/-0.08 vs 0.90+/-0.06 in C, p<0.006, and vs 1.45+/-0.07 in EH, p<0.001. CONCLUSION: The data point to a direct cardioremodeling role for Ang II and support a role of Ang II type 2 receptor (AT2R) signaling as involved in the lack of cardiovascular remodeling in BS/GS. However, further studies using more direct approaches to demonstrate the effects of AT2R signaling must be pursued.

Myocardial perfusion defects in Bartter and Gitelman syndromes.

BACKGROUND: Normotensive hypokalaemic tubulopathies (Bartter and Gitelman syndromes (BS/GS)) are genetic diseases that are considered benign. However, QT prolongation, left ventricular dysfunction and reduction of cardiac index upon exercise leading to arrhythmias and sudden cardiac death have been reported in these patients. Hence, we aimed to verifying whether an isometric exercise could represent a useful tool for the identification of patients at risk for future cardiac events. PATIENTS AND METHODS: Myocardial function (MF) and perfusion, evaluated as myocardial blood flow (MBF) of 10 BS/GS patients and 10 healthy controls, were investigated at rest and during isometric exercise. MF and MBF were evaluated using quantitative two-dimensional and myocardial contrast echocardiography. RESULTS: BS/GS patients had normal baseline MF and MBF. During exercise in BS/GS patients, corrected QT (QTc) was prolonged to peak value of 494 +/- 9.1 ms (P < 0.001). In controls, MF increased from resting to peak exercise (left ventricular ejection fraction: 65 +/- 4% to 78 +/- 5%, P < 0.003) while in seven BS/GS patients (Group 1) it declined (64 +/- 5% to 43 +/- 9%, P < 0.001). Myocardial perfusion increased upon exercise in controls as shown by changes of its markers: beta (a measure of myocardial flow velocity; 0.89 +/- 0.12 vs. 0.99 +/- 0.12, P < 0.001) and myocardial blood volume (14.4 +/- 2 vs. 20.2 +/- 0.25, P < 0.001), while in Group 1 BS/GS it decreased (0.87 +/- 0.15 vs. 0.67 +/- 0.15, P < 0.001; and 14.5 +/- 1.9 vs. 8.3 +/- 0.22, P < 0.001, respectively). CONCLUSIONS: Our results document for the first time that exercise induce coronary microvascular and myocardial defects in BS/GS patients. Therefore, this may challenge the idea that BS/GS are benign diseases. In addition, the diagnostic approach to these syndromes should include an in-depth cardiac assessment in order to identify patients at higher risk.

Primary aldosteronism - part I: prevalence, screening, and selection of cases for adrenal vein sampling.

Over the last few years compelling evidence has been gathered to support the view that primary aldosteronism (PA) is far more prevalent than usually held: its prevalence rate among consecutive newly diagnosed hypertensive patients referred to hypertension centers can be as high as 11.2%. Moreover, about 4.8% of cases are a surgically curable endocrine form of hypertension, and the majority of cases do not exhibit hypokalemia at the time of clinical presentation. The impact of these results on the strategy to be used in the clinical investigation of patients with hypertension is discussed in light of novel information on the optimal screening strategy to be used for pinpointing the PA patients from the vast array of hypertensive patients.

Primary aldosteronism: part II: subtype differentiation and treatment.

After discussing in Part I (Rossi et al, J Nephrol. 2008;21:447-454) the screening strategy to identify the hypertensive patients with primary aldosteronism (PA), we report here an update on the methodology for the further diagnostic work-up and treatment of PA patients. The most common forms of PA are aldosterone-producing adenoma (APA) and adrenocortical hyperplasia (BAH), which are unilateral or bilateral sources of aldosterone excess secretion, respectively. Since APA needs a surgical approach, in contrast to BAH which requires medical treatment, it is crucial to clearly delineate a diagnostic work-up aimed at discriminating the 2 forms. Clinical usefulness and accuracy of adrenal vein sampling, imaging tests (e.g., computed tomography and magnetic resonance) and mineralocorticoid adrenocortical scintigraphy are discussed in detail.

Endocrine arterial hypertension: diagnostic approach in clinical practice.

Endocrine arterial hypertension (EAH) a condition in which hormone excess results in clinically significant hypertension is a rare cause of hypertension. However in the last years its prevalence has increased, mostly due to the improvement of diagnostic work-up. In clinical practice, hypertensive subjects with suspicion of EAH currently undergo hormonal screening of the renin-aldosterone and catecholamines and glucocorticoids excess. This paper reviews current understanding for earlier recognition of the main forms of EAH and discusses screening laboratory methods and localization techniques that have enhanced the clinician's ability to make the diagnosis of EAH. Primary aldosteronism (PA) has recently been recognised as the most frequent cause of EAH. The aldosterone to renin ratio (ARR) is a highly recommended screening test for PA. When ARR is increased, confirmatory tests as saline infusion or fludrocortisone suppression are required. Differential diagnosis of PA requires adrenal gland imaging by computed tomography (CT) or magnetic resonance imaging (MRI), biochemical testing of the aldosterone response to posture, and selective adrenal venous sampling to differentiate unilateral aldosterone-producing adenoma from bilateral hyperplasia. Hypertension is frequently found in endogenous Cushing's Syndrome (CS). Twenty-four-hour urinary free cortisol measurement is the gold standard for the diagnosis of CS, but it must be confirmed by the overnight dexamethasone suppression test. CT and MRI are the primary imaging studies to perform, while scintigraphy is a useful confirmatory method. The most specific and sensitive diagnostic test for catecholamine-producing neoplasms is determination of urinary metanephrine levels; the neoplasms can be located by CT, MRI and metaiodo-benzylguanidine scintigraphy.

Endocrine arterial hypertension: therapeutic approach in clinical practice.

This review describes the therapeutic approach of endocrine arterial hypertension in clinical practice. In mineralocorticoid-related hypertension, adrenalectomy is the treatment of choice for aldosterone-producing adenomas and monolateral primary aldosteronism, whereas pharmacologic blood pressure (BP) control is indicated for the other forms of primary aldosteronism such as bilateral adrenal hyperplasia. Spironolactone is the drug of choice, but intolerable side effects limit its use; amiloride or eplerenone are a valid alternative. If BP remains uncontrolled, angiotensin converting enzyme inhibitors (ACE-I), angiotensin II receptor antagonists (AII-RA) and calcium channel blockers (CCB) may be added. Hypertension accompanying Cushing's syndrome can be approached with surgery, but antihypertensive treatment both pre- and postoperative is required as well. Eplerenone, AII-RA and ACE-I are indicated, while peroxisome proliferator activated receptor upsilon agonists may help for the insulin resistance syndrome. Drugs that suppress steroidogenesis should be used with care because of their serious side effects. Subjects with catecholamine-dependent hypertension due to a neuroendocrine neoplasm need to undergo preoperative alpha-adrenergic blockade with phenoxybenzamine or doxazozine. When adequate alpha-adrenergic blockade is achieved, beta-adrenergic blockade with low dose propranolol may be added. If target BP is not achieved, CCB and/or metyrosine are indicated. Laparoscopic adrenalectomy is the procedure of choice for solitary intra-adrenal neoplasms <8 cm. Acute hypertensive crises that may occur before or during surgery should be treated intravenously with sodium nitroprusside, phentolamine, nicardipine or labetalol. For malignant neoplasms, chemo- and radiopharmaceutical therapy may be considered.

Intravenous thrombolysis in the emergency department for the treatment of acute ischaemic stroke.

BACKGROUND AND AIMS: Thrombolytic therapy with intravenous recombinant tissue plasminogen activator (rt-PA) improves outcome in patients with ischaemic stroke treated within 3 h of symptom onset, but its extended implementation is limited. A pilot study was designed to verify whether evaluation of patients with acute ischaemic stroke and their treatment with intravenous rt-PA in the emergency department (ED), followed by transportation to a semi-intensive stroke care unit, offers a safe and effective organisational solution to provide intravenous thrombolysis to acute stroke patients when a stroke unit (SU) is not available. METHODS: After checking for inclusion and exclusion criteria, ED doctors contacted the stroke team with a single page, located family members and urgently obtained computed tomography scan and laboratory tests. A stroke team investigator clinically assessed the patient, obtained written informed consent and supervised intravenous rt-PA in the ED. After treatment, the patient was transferred to the SU for rehabilitation and treatment of complications, under supervision of the same stroke team investigator. RESULTS: 52 patients were treated with intravenous rt-PA within 3 h of symptom onset. 20 patients (38%) improved neurologically after 24 h, the number increased to 30 (58%) after one week. At 3 months 22 patients had a favourable outcome (43%). The 3-month mortality rate was 12%. Symptomatic cerebral haemorrhage was observed in two patients (4%). CONCLUSIONS: Intravenous rt-PA administration in the ED is an effective organisational solution for acute ischaemic stroke when an SU is not established.

Gene expression, localization, and characterization of endothelin A and B receptors in the human adrenal cortex.

Compelling evidence indicates that the endothelium-derived potent vasoconstrictor endothelin-1 (ET-1) stimulates aldosterone secretion by interacting with specific receptors. Although two different ET-1 receptors have been identified and cloned, the receptor subtype involved in mediating aldosterone secretion is still unknown. Accordingly, we wished to investigate whether the genes of ET-1 and of its receptors A and B are expressed in the normal human adrenal cortex. We designed specific primers for ET-1 and the ETA and ETB receptors genes and developed a reverse transcription polymerase chain reaction (RT-PCR) with chemiluminescent quantitation of the cDNA. In addition, we carried out 125I ET-1 displacement studies with cold ET-1, ET-3 and the specific ETA and ETB ligands BQ123 and sarafotoxin 6C. Localization of each receptor subtype was also investigated by autoradiography. Binding experiments were first individually analyzed by Scatchard and Hofstee plot and then coanalyzed by the nonlinear iterative curve fitting program Ligand. Histologically normal adrenal cortex tissue, obtained from kidney cancer patients (n = 7), and an aldosterone-producing adenoma (APA), which is histogenetically derived from the zona glomerulosa (ZG) cells, were studied. Results showed that the ET-1, ETA and ETB mRNA can be detected by RT-PCR in all adrenal cortices as well as in the APA. The best fitting of the 125I ET-1 displacement binding data was consistently provided by a two-site model both in the normal adrenal cortex (F = 22.1, P < 0.0001) and in the APA (F = 18.4, P < 0.0001). In the former the density (Bmax) of the ETA and ETB subtype was 2.6 +/- 0.5 pmol/mg protein (m +/- SEM) and 1.19 +/- 0.6, respectively. The dissociation constant (Kd) of ET-1, ET-3, S6C, and BQ-123 for each receptor subtype resulted to be within the range reported for human tissue for the ETA and ETB receptors. In the APA tissue the Bmax tended to be lower (1.33 and 0.8 pmol/mg protein, for the ETA and ETB, respectively) but the Kd were similar. Autoradiographic studies confirmed the presence of both receptor subtypes on the ZG as well as on APA cells. Thus, the genes of ET-1 and both its receptor subtypes ETA and ETB are actively transcribed in the human adrenal cortex. Furthermore, both receptor subtypes are translated into proteins in ZG and APA cells.

Pulse hypertension: a new component of the metabolic syndrome in elderly women?

The classification of arterial hypertension (HT) to define metabolic syndrome (MS) is unclear in that different cutoffs of blood pressure (BP) have been proposed. We evaluated the categorization of HT most qualified to define MS in relationship with coronary heart disease (CHD) mortality at a population level. A total of 3257 subjects aged > or =65 years were followed up for 12 years. MS was defined according to the criteria of the National Education Cholesterol Program using three different categories of HT: MS-1 (systolic blood pressure (SBP) > or =130 and diastolic blood pressure (DBP) > or =85 mm Hg), MS-2 (SBP > or =130 or DBP > or =85 mm Hg) and MS-3 (pulse pressure (PP) > or =75 mm Hg in men and > or =80 mm Hg in women). Gender-specific adjusted hazard ratio (HR) with 95% confidence intervals (CI) for CHD mortality was derived from Cox analysis in the three MS groups, both including and excluding antihypertensive treatment. In women with MS untreated for HT, the risk of CHD mortality was always significantly higher than in those without MS, independent of categorization; the HR of MS was 1.73 (CI 1.12-2.67) using MS-1, 1.75 (CI 1.10-2.83) using MS-2 and 2.39 (CI 3.71-1.31) using MS-3. In women with MS treated for HT, the HR of CHD mortality was significantly increased only in the MS-3 group (1.92, CI 1.1-2.88). MS did not predict CHD in men. In conclusion, MS can predict CHD mortality in elderly women with untreated HT but not in those with treated HT; in the latter, PP is the most predictive BP value.

Serum uric acid shows a J-shaped trend with coronary mortality in non-insulin-dependent diabetic elderly people. The CArdiovascular STudy in the ELderly (CASTEL).

The relationship between serum uric acid (SUA) and risk of coronary heart disease (CHD) mortality remains controversial, particularly in diabetic subjects. The aim of the present study is to evaluate whether SUA independently predicts CHD mortality in non-insulin-dependent elderly people from the general population and to investigate the interactions between SUA and other risk factors. Five hundred and eighty-one subjects aged >/=65 years with non-insulin-dependent diabetes mellitus were prospectively studied in the frame of the CArdiovascular STudy in the ELderly (CASTEL). Historical and clinical data, blood tests and 12-year fatal events were recorded. SUA as a continuous item was divided into tertiles and, for each tertile, adjusted relative risk (RR) with 95% confidence intervals (CI) was derived from multivariate Cox analysis. CHD mortality was predicted by SUA in a J-shaped manner. Mortality rate was 7.9% (RR 1.28, CI 1.05-1.72), 6.0% (reference tertile) and 12.1% (RR 1.76, CI 1.18-2.27) in the increasing tertiles of SUA, respectively, without any difference between genders. In diabetic elderly subjects, SUA independently predicts the risk of CHD mortality in a J-shaped manner.

Specific cellular features of atheroma associated with development of neointima after carotid endarterectomy: the carotid atherosclerosis and restenosis study.

BACKGROUND: The purpose of this study was to investigate whether some cellular and molecular features of tissue retrieved at carotid endarterectomy are associated with the extent of neointima formation at ultrasound follow-up. METHODS AND RESULTS: One hundred fifty patients were studied. Endarterectomy specimens were tested by immunocytochemistry with the use of (1) monoclonal antibodies that identify smooth muscle cells (SMCs) and fetal-type SMCs on the basis of smooth muscle and nonmuscle myosin content, (2) the anti-macrophage HAM 56, and (3) the anti-lymphocyte CD45RO. The maximum intima-media thickness (M-IMT) of the revascularized vessel was assessed by the use of B-mode ultrasonography 6 months after surgery. The M-IMT values were related positively to the number of SMCs (r=0.534, P<0.0005) and negatively to that of macrophages and lymphocytes (r=-0.428, P<0.0005, and -0.538, P=0.001, respectively). Patients were classified as class 1 (M-IMT 1.3 mm). An abundance of SMCs, mostly of fetal type, was found in the plaque of class 3 patients, whereas lesions from class 1 patients were rich in macrophages and lymphocytes. In the multivariate analysis, factors related to M-IMT were the number of SMCs and the percentage of fetal-type SMCs present in the plaque. CONCLUSIONS: Although the classic risk factors did not play a role, an abundance of SMCs and a scarcity of macrophages characterized the primary lesion of patients in whom neointima developed after surgery. In patients in whom neointima did not develop, lesions were rich in macrophages and lymphocytes. This approach can be useful in defining patients at risk of restenosis.

Homocysteine-lowering treatment in coronary heart disease.

Homocysteine (Hcy) is a sulphur-containing amino acid product of methionine's metabolism. Hyperhomocysteinemia (HHcy) is considered an independent risk factor for cardiovascular (CV) disease, at least in high-risk patients. In fact, evidence indicates that although mild HHcy may be regarded as a minor risk factor for CHD in low-risk patients, it can play a role in triggering new events in patients with known CHD, also by interacting with the "classical" CV risk factors. This is of much interest because HHcy represents a correctable risk factor, inasmuch vitamin supplementation as has been shown to effectively lower total homocysteine plasma levels (tHcy). While case-control and cross-sectional studies have consistently demonstrated an association of HHcy with CV disease, prospective studies have given conflicting results. Moreover, the effect of the homocysteine-lowering treatment in preventing CV events is still under debate. Thus, it remains unclear which patients should be screened for HHcy and which ones should be treated to lower tHcy. In this paper we shall report and discuss knowledge on the potential role of HHcy in the development of CHD and on the benefits due to tHcy-lowering treatment with vitamins.

High heart rate: a risk factor for cardiovascular death in elderly men.

OBJECTIVE: To examine the association between heart rate and 12-year incidence rates of total and cardiovascular death in a cohort of elderly subjects stratified by sex. SUBJECTS AND METHODS: The study was carried out in 763 white men and 1175 women aged 65 years or older who were participating in the Cardiovascular Study in the Elderly. Subjects were divided into quintiles of heart rate; the top quintile comprised those with a heart rate of greater than 80/min and the bottom quintile, those with a heart rate of less than 64/min. RESULTS: In the men, the number of deaths from cardiovascular causes was significantly increased in those in the top quintile of heart rate (crude relative risk, 1.55) but decreased in those in the bottom quintile (crude relative risk, 0.65). Similar relationships were found in the women, but the associations did not reach statistical significance (all-cause, P = .11; cardiovascular, P = .15). After adjustment for baseline age, body mass index, hypertension, diabetes mellitus, angina or previous myocardial infarction (coronary heart disease), regular medication, lipid levels, smoking, alcohol intake, forced expiratory volume in 1 second, and other confounders, the relative risk for cardiovascular death in the men was 1.38 (95% confidence interval, 0.94-2.03) for the subjects in the top quintile of heart rate and 0.82 (95% confidence interval, 0.52-1.28) for those in the bottom quintile. In the Cox analysis, predictors of time to cardiovascular death were heart rate (P < .001), age (P < .001), coronary heart disease (P < .001), clinical heart failure (P = .001), diabetes mellitus (P = .001), hypertension (P = .02), and triglyceride levels (P = .04), whereas total (P = .20) and high-density lipoprotein-cholesterol (P = .21) levels and smoking (P = .74) were found to be nonsignificant by the model. The heart rate-cardiovascular death association held true when subjects who died in 2 years after enrollment were excluded (P = .008). CONCLUSIONS: An elevated heart rate may be a strong predictor of cardiovascular death in elderly men. Conversely, a low heart rate is related to a better outcome in these subjects.

Clinical relevance of nighttime blood pressure and of daytime blood pressure variability.

BACKGROUND: The purpose of this study was to assess whether hypertensive target organ damage is related to average nighttime blood pressure (BP) and to BP variability. METHODS: Sixty-seven normotensive subjects and 171 borderline, 309 mild, 140 moderate, and 41 severe hypertensive patients were studied with noninvasive ambulatory BP monitoring. Each subject was assigned a target organ damage score of 0 to 5 on the basis of funduscopic changes and degree of left ventricular hypertrophy calculated from electrocardiogram and chest roentgenogram. RESULTS: When the 728 subjects were subdivided into five classes of increasing daytime BP, in each class a significantly higher degree of target organ damage was present in the subjects with higher nighttime diastolic BP. A similar, although nonsignificant, trend was observed in the subjects with higher nighttime systolic BP. In particular, higher nighttime BP levels were accompanied by a more severe degree of left ventricular hypertrophy. As for variability, subjects with higher daytime systolic BP SD, but not with higher daytime diastolic SD, displayed a more severe degree of target organ damage; this was accounted for by a higher degree of retinal abnormalities. The association between target organ damage and systolic BP SD was present both in men and women, while that with nighttime BP was present only in men. No relationship was found between degree of cardiovascular complications and peaks of pressure. CONCLUSIONS: These results suggest that a reduced day-night BP difference and an increased daytime BP variability, evaluated as the SD, are associated with a higher degree of hypertensive cardiovascular complications. Whether this BP profile is the cause or the consequence of target organ damage remains to be established.

Interactions between endothelin-1 and the renin-angiotensin-aldosterone system.

The renin-angiotensin-aldosterone (RAA) system and the endothelin (ET) system entail the most potent vasopressor mechanisms identified to date. Although they were studied in depth in relation to arterial hypertension and cardiovascular diseases, limited information on their interrelationships in causing hypertension and related target organ damage exists. The identification of consensus sequences for jun in the regulatory region of the preproendothelin-1 (ppET-1) gene raised the possibility of its transcriptional regulation by angiotensin II (Ang II). This was confirmed by the finding that stimulation with Ang II of cultured vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) induced expression of the ppET-1 gene and synthesis of ET-1. Endogenously produced ET-1 was found to contribute to the hypertrophic response of cardiomyocytes to Ang II and thereby to cardiac hypertrophy. Furthermore, ET-1 exerts multifaceted effects on the RAA system, such as dose-dependent inhibition of renin synthesis, and stimulation of aldosterone secretion. The finding of abundant specific ET-1 receptors in the adrenocortical zona glomerulosa (ZG) suggested a direct secretagogue effect of ET-1. In rats, ETB receptors mediate such an effect, whilst in humans, both ETA and ETB receptor subtypes intervene in regulating the transcription of the aldosterone synthase gene. In addition, ET-1 stimulates DNA synthesis and proliferation of ZG cells via ETA receptors and, therefore, might play a role in cell turnover of the normal adrenal cortex and in the onset of adrenal tumours. Studies on the in vivo interactions between ETs and the RAA system have given conflicting results, insofar as some suggested a participation of ET-1 in the pressor and cellular effects of exogenously administered Ang II, whereas others did not in the transgenic TGR(Ren 2m)27 rats and in the two-kidney, one clip.

24-hour leg and forearm haemodynamics in transected spinal cord subjects.

OBJECTIVE: A circadian rhythm of blood pressure has been demonstrated both in subjects who are physically active during the day and in those confined to bed. The study of the circadian rhythm of arterial flow and peripheral resistance, on the other hand, is limited to pioneer experiments. This paper is aimed at demonstrating that leg peripheral resistance has circadian fluctuations which are modulated by spinal neural traffic. METHODS: Eleven normal (able-bodied) human subjects and 11 patients with spinal transection due to spinal cord injury (SCI) were studied. They were confined to bed for 24 h. Blood pressure and heart rate were monitored every 15 min with an automatic device and leg flow with an automatic strain-gauge plethysmograph synchronised to the pressurometer. Peripheral resistance was calculated at the same intervals. RESULTS: In able-bodied subjects leg resistance was significantly higher during waking hours (when the sympathetic system is more activated) than during sleep, while in subjects with spinal cord injury no difference was detected between day-time and night-time. CONCLUSIONS: The circadian rhythm is controlled by adrenergic fibres transmitted via the spinal cord.

Autocrine-paracrine role of endothelin-1 in the regulation of aldosterone synthase expression and intracellular Ca2+ in human adrenocortical carcinoma NCI-H295 cells.

The role played by endothelin (ET-1) and its receptor subtypes A and B (ET(A) and ET(B)) in the functional regulation of human NCI-H295 adrenocortical carcinoma cells has been investigated. Reverse transcription-PCR with primers specific for prepro-ET-1, human ET-1 converting enzyme-1, ET(A), and ET(B) complementary DNAs consistently demonstrated the expression of all genes in NCI-H295 cells. The presence of mature ET-1 and both its receptor subtypes was confirmed by immunocytochemistry and autoradiography, respectively. Aldosterone synthase (AS) messenger RNA was also detected in NCI-H295 cells, and AS gene expression was enhanced by both ET-1 and the specific ET(B) agonist IRL-1620; this effect was not inhibited by either the ET(A) antagonist BQ-123 or the ET(B) antagonist BQ-788. A clear-cut increase in the intracellular Ca2+ concentration in NCI-H295 cells in response to ET(B), but not ET(A), activation was observed. In light of these findings, the following conclusions can be drawn: 1) NCI-H295 cells possess an active ET-1 biosynthetic pathway and are provided with ET(A) and ET(B) receptors; 2) ET-1 regulates in an autocrine/paracrine fashion the secretion of aldosterone by NCI-H295 cells by enhancing both AS transcription and raising the intracellular Ca2+ concentration; and 3) the former effect of ET-1 probably involves the activation of both receptor subtypes, whereas calcium response is exclusively mediated by the ET(B) receptor.