Care manager to control cardiovascular risk factors in primary care: the Raffaello cluster randomized trial.

BACKGROUND AND AIM: This cluster randomized trial evaluated the efficacy of a disease and care management (D&CM) model in cardiovascular (CVD) prevention in primary care. METHODS AND RESULTS: Eligible subjects had ≥ 1 among: blood pressure ≥ 140/90 mmHg; glycated hemoglobin ≥ 7%; LDL-cholesterol ≥ 160 or ≥ 100 mg/dL (primary or secondary prevention, respectively); BMI ≥ 30; current smoking. The D&CM intervention included a teamwork including nurses as care managers for the implementation of tailored care plans. Control group was allocated to usual-care. The main outcome was the proportion of subjects achieving recommended clinical targets for ≥ 1 of uncontrolled CVD risk factors at 12-month. During 2008-2009 we enrolled 920 subjects in the Abruzzo/Marche regions, Italy. Following the exclusion of L'Aquila due to 2009 earthquake, final analyses included 762 subjects. The primary outcome was achieved by 39.1% (95%CI: 34.2-44.2) and 25.2% (95%CI: 20.9-29.9) of subjects in the intervention and usual-care group, respectively (p < 0.001). The D&CM intervention significantly increased the proportion of subjects who achieved clinical targets for both diabetes and hypertension, with no differences in hypercholesterolemia, smoking status and obesity. CONCLUSIONS: The D&CM intervention was effective in controlling cardiovascular risk factors, in particular hypertension and diabetes. Numbers needed to treat were small. Such intervention may deserve further consideration in clinical practice. REGISTRATION NUMBER: ACTRN12611000813987.

Carotid artery atherosclerosis in hypertensive patients with a functional LDL receptor-related protein 6 gene variant.

BACKGROUND AND AIMS: Rare (611C) and common (1062V) variants of the Low-Density Lipoprotein Receptor-Related Protein 6 (LRP6) display reduced activation of Wnt/ß-catenin signaling. The rare gene variant was associated with hypertension, metabolic abnormalities, and early coronary artery disease. We investigated whether the common 1062V LRP6 variant was related to carotid artery atherosclerosis (CAA) in hypertensive patients. METHODS AND RESULTS: Retrospective study of 334 hypertensive patients (<65 years old) who underwent carotid artery ultrasonography. Hypertension, type 2 diabetes, dyslipidemia, glomerular filtration rate, and smoking habit were evaluated. CAA was defined by the presence of atherosclerotic plaques (focal intima-media thickness ≥ 1.3 mm). Logistic regression models were used to estimate the independent effect of 1062V allele. The relationship between LRP6 genotypes and LRP6 gene expression in carotid plaques was also investigated. No difference was observed between genotypes in clinical variables except for a slightly higher fasting glucose in 1062V carriers. The 1062V LRP6 variant was an independent risk factor for CAA in both unadjusted (OR 2.08, 95%CI 1.27-3.41, p=0.003) and adjusted models (OR 1.92, 95%CI 1.09-3.39, p=0.02). LRP6 was expressed in carotid atherosclerotic plaques at significantly lower levels (p=0.015) in 1062V carriers. CONCLUSION: Beside the role of established risk factors, 1062V variant of LRP6 and CAA are strongly associated in hypertensive patients, making LRP6 a novel relevant candidate gene for atherosclerosis in the presence of hypertension.

Angiotensin II stimulates and atrial natriuretic peptide inhibits human visceral adipocyte growth.

OBJECTIVE: Cardiovascular peptides such as angiotensin II (Ang II) and atrial natriuretic peptide (ANP) have metabolic effects on adipose cells. These peptides might also regulate adipocyte proliferation and visceral adipose tissue (VAT) expansion. Well-differentiated and stabilized primary cultures of human visceral mature adipocytes (MA) and in vitro-differentiated preadipocytes (DPA) were used as a model to study regulation of VAT expansion. METHODS: Adipocyte differentiation was evaluated by Oil Red O staining and antiperilipin antibodies. MA and DPA from intra- and retro-peritoneal depots were treated with increasing Ang II (with or without valsartan, a highly selective, competitive, 'surmountable' AT1 antagonist devoid of peroxisome proliferator-activated receptor gamma agonistic activity) or ANP concentrations. Cell counts and bromodeoxyuridine incorporation were used to evaluate proliferation. Apoptosis was evaluated by Hoechst 33342 staining. 8-Bromo cyclic guanosine monophosphate (8Br-cGMP) was used to investigate ANP effects, and real-time PCR to evaluate Ang II and ANP receptors' expression. RESULTS: Cell proliferation was progressively stimulated by increasing Ang II concentrations (starting at 10-11 M) and inhibited by ANP (already at 10-13 M) in both MA and DPA. Co-incubation with increasing Ang II concentrations and valsartan indicated that Ang II effects were AT1-mediated. Indeed, AT2 receptors were not expressed. Valsartan alone slightly inhibited basal proliferation indicating an autocrine/paracrine growth factor-like effect of endogenous, adipocyte-derived Ang II. 8Br-cGMP experiments indicated that the effects of ANP were mediated by the guanylyl cyclase type A receptor. CONCLUSION: A cell-culture model to study VAT growth showed stimulation by Ang II and inhibition by ANP at physiological concentrations. Because similar effects are likely to occur in vivo, Ang II and ANP might be important modulators of VAT expansion and associated metabolic and cardiovascular consequences.

Heart block and hyperthyroidism. Report of two cases.

In two patients with hyperthyroidism who had no signs of heart disease, first-degree heart block with tall and large P waves occurred. In one patient, a left bundle-branch block and transient complete heart block with Stokes-Adams episodes also occurred, although there was no verifiable evidence of acute inflammatory disease.

Reproducibility and clinical value of the trough-to-peak ratio of the antihypertensive effect: evidence from the sample study.

The objectives of our study were to assess the reproducibility of the trough-to-peak ratio (T/P) and to see whether a high T/P is accompanied by more organ protection or vice versa. The study included 175 (mean+/-SD age, 51+/-9 years) subjects with mild-moderate essential hypertension who had echocardiographic evidence of left ventricular (LV) hypertrophy taken from the SAMPLE study (Study on Ambulatory Monitoring of Blood Pressure and Lisinopril Evaluation), an open-label multicenter study. The study included a 3-week washout pretreatment period, a 12-month treatment period with lisinopril (n=84) or lisinopril plus hydrochlorothiazide (n=91) once daily, and a 4-week placebo follow-up period. Results of 24-hour ambulatory blood pressure monitoring and echocardiographic determination of left ventricular mass index (LVMI) were obtained before and after 3 and 12 months of treatment. T/Ps were computed in each patient by dividing the systolic and diastolic blood pressure changes at trough (changes in the last 2 hours of the monitoring period) by those at peak (average of the 2 adjacent hours with the maximal blood pressure reduction between the 2nd and 8th hour from drug intake) after 3 and 12 months of treatment. Average 24-hour blood pressure was similarly reduced at 3 and 12 months. Trough blood pressure changes at 3 and 12 months were closely correlated, as were the corresponding peak blood pressure changes. However, the 3- and 12-month T/Ps correlated to a lesser degree (r<0.42). Furthermore, the reduction of LVMI induced by treatment was similarly correlated with the treatment-induced reduction in 24-hour average, trough, and peak blood pressures but not with the T/Ps. This was also evident when the contribution to LV hypertrophy regression by 24-hour blood pressure changes and T/Ps was assessed in a multivariate regression analysis. In patients with a T/P >/=0.5 or <0.5, the regression of LVMI was similar. In conclusion, peak and trough blood pressure changes are reproducible and predict the regression of LVMI induced by treatment as well as average 24-hour blood pressure. T/Ps are less reproducible, and their value does not predict regression of organ damage by antihypertensive treatment.

Local renin-angiotensin system in human adrenals and aldosteronomas.

The local renin-angiotensin system may regulate adrenal cell growth and function. Angiotensinogen, renin, and angiotensin converting enzyme gene expression were studied in four normal adrenal glands (removed from patients with renal carcinomas) and five aldosterone-secreting adenomas. Northern blot analysis showed expression of angiotensinogen messenger RNA (mRNA) in normal adrenals at levels approximately 35-fold lower than liver and sixfold lower than kidney. Similar angiotensinogen mRNA levels were present in two aldosteronomas, whereas a third had levels approximately 50% of those found in kidney. Renin mRNA was detectable in most normal adrenals and in three adenomas, one of which had relatively high renin mRNA levels. Angiotensin converting enzyme gene was expressed in adrenal tissue and in three adenomas. Portions from these normal adrenals and two of these aldosteronomas, as well as samples from two other adrenals and three aldosteronomas, were also studied in an in vitro superfusion system coupled with active renin radioimmunometric assay, angiotensin II/III, and aldosterone radioimmunoassay. Total amounts of active renin and angiotensin II/III released from normal adrenals during 270 minutes of superfusion were higher than the amounts released from aldosteronomas (312 +/- 35 versus 187 +/- 43 and 823 +/- 100 versus 436 +/- 55 pg/100 mg tissue, respectively; mean +/- SEM, p less than 0.05), whereas aldosterone release from the adenomatous tissue was approximately threefold higher (320 +/- 21 versus 115 +/- 18 ng/100 mg tissue; mean +/- SEM, p less than 0.01). Total amounts of active renin and angiotensin II/III released by normal or adenomatous adrenal samples exceeded threefold to fourfold the amounts extracted from similar samples of the same surgical specimen.(ABSTRACT TRUNCATED AT 250 WORDS)

Low calorie diet enhances renal, hemodynamic, and humoral effects of exogenous atrial natriuretic peptide in obese hypertensives.

The expression of the natriuretic peptide clearance receptor is abundant in human and rat adipose tissue, where it is specifically inhibited by fasting. In obese hypertensives, plasma atrial natriuretic peptide (ANP) levels were found to be lower than in obese normotensives. Therefore, the increased adipose mass might influence ANP levels and/or its biological activity. The aim of the present study was to evaluate whether the humoral, hemodynamic, and renal effects of exogenous ANP in obese hypertensives might be enhanced by a very low calorie diet. Eight obese hypertensives received a bolus injection of ANP (0.6 mg/kg) after 2 weeks of a normal calorie/normal sodium diet, and blood pressure (BP), heart rate, ANP, cGMP, plasma renin activity, and aldosterone were evaluated for 2 hours before and after the injection. Diuresis and natriuresis were measured every 30 minutes. The patients then started a low calorie/normal sodium diet (510 kcal/150 mmol/d) for 4 days, and then the ANP injection protocol was repeated. The low calorie diet induced a slight weight loss (from 90.6+/-1.1 to 87. 7+/-1.2 kg; P<0.01), which was accompanied by increase of cGMP excretion (from 146.0+/-10.1 to 154.5+/-9.5 nmol/24 h; P<0.05) together with a reduction of BP (P<0.01 versus basal levels). ANP injection after diet was followed by an increase of ANP levels similar to that observed before diet, but plasma cGMP, diuresis, and natriuresis increased significantly only after diet. Similarly, the decrease of BP after ANP administration was significantly higher after diet (change in mean arterial pressure, -6.4+/-0.7 versus -4. 0+/-0.6 mm Hg; P<0.05) as well as that of aldosterone (P<0.01). These data show that a low calorie diet enhances the humoral, renal, and hemodynamic effects of ANP in obese hypertensives and confirm the importance of caloric intake in modulating the biological activity of ANP, suggesting that the natriuretic peptide system can play a role in the acute changes of natriuresis and diuresis associated with caloric restriction.

Absence of somatic mutations in natriuretic peptide receptor type A gene in human aldosterone-secreting adenomas.

Somatic mutations of genes codifying for key regulatory proteins are the cause of different types of hormone-secreting adenomas. Natriuretic peptides (NP) are the strongest inhibitors of aldosterone secretion but aldosterone-secreting adenomas (aldosteronomas) are resistant to this inhibition and have reduced binding sites for NPs. The objective of this study was to sequence the entire coding region of the NP receptor type A (NPRA, codified by the Npr1 gene) to find loss-of-function somatic mutations. Total RNA was extracted from eight aldosteronomas and cDNA was synthesized. NPRA mRNA expression was evaluated by Northern blot analysis and compared with beta-actin mRNA as the housekeeping gene. Twelve primer couples were designed on the basis of the Npr1 gene organization to amplify, by PCR, all 22 coding exons of the gene. The two strands of amplified DNAs were purified and directly sequenced by automated capillary sequencer. NPRA mRNA expression did not differ among aldosteronomas. Npr1 open reading frame sequences obtained from eight aldosteronomas did not contain any mutation. The coding sequences of all 22 exons were identical in all samples and identical to published sequences. In the 3'-untranslated region (3'-UTR) a new length difference 3C/4C polymorphism was found at position 15 129 (three adenomas were 3C/4C and two were 3C/3C). Such a 3C/4C polymorphism was present in genomic DNA from 80 control subjects (25, 4C/4C; 40, 3C/4C; 15, 3C/3C). Mutations in the coding exons of the Npr1 gene do not appear to be a common cause of aldosteronomas. Moreover, the exons of Npr1 encoding for the translated portion of mRNA do not appear to be prone to polymorphisms. The polymorphism identified in the 3'-UTR might affect mRNA stability resulting in lower receptor synthesis, but it is not likely to confer a predisposition to the development of aldosteronomas.

Tolerability and well-being with indapamide in the treatment of mild-moderate hypertension. An Italian multicenter study.

Since hypertension is an important risk factor of cardiovascular morbidity and mortality that can be at least in part decreased by pharmacologic reduction in elevated blood pressure, it is necessary that an antihypertensive agent be effective, but at the same time well tolerated and, according to some recent hypotheses, have no deleterious effect on serum electrolyte levels, as well as lipoprotein and glucose tolerance. However, due to different cultural and social backgrounds, lifestyles, and so on, the tolerability may differ from one population to another and the conclusions drawn from a population cannot be extrapolated to people of other countries. For these reasons, the well-being of patients, as well as the tolerability of indapamide, a non-thiazide diuretic, have been investigated in patients with hypertension of mild and moderate degree from different parts of Italy with a satisfactory blood-pressure response to this drug (-22.8 +/- 0.6/-17.1 +/- 0.5 mm Hg). Simultaneous to the significant blood-pressure reduction, the only significant change among the metabolic effects was a slight reduction in plasma potassium levels (-0.37 +/- 0.03 meq/liter). The tolerability was, on the whole, very good with a tendency toward an improvement of well-being in patients, the majority of whom were already asymptomatic before starting the treatment.

Role of renal kallikrein in modulating the antihypertensive effect of a single oral dose of captopril in normal- and low-renin essential hypertensives.

The antihypertensive efficacy of angiotensin converting enzyme (ACE) inhibitors may result from the blockade of angiotensin II formation but also, theoretically, from the inhibition of kinin breakdown. To test whether a blunted activity of the kallikrein-kinin system might account for the failure of ACE inhibitors in lowering blood pressure (BP) in patients in whom the renin-angiotensin system (RAS) is not enhanced, 31 essential hypertensives with normal or low plasma renin activity (PRA) were evaluated before and after a single oral dose (50 mg) of captopril. A significant fall, in both systolic and diastolic BP, was obtained in the subgroup of patients who were classified as 'normal-kallikrein hypertensives' according to whether their pretreatment urinary kallikrein excretion was within the normal range, while no significant change in BP was observed in 'low-kallikrein hypertensives'. Furthermore, the mean percentage fall in mean BP, throughout the 2 h following captopril administration, was significantly related to the basal value of urinary kallikrein excretion (r = 0.47, P less than 0.05) in all the patients. Our results suggest that blunted activity of the kallikrein system might be responsible for failure of captopril to lower BP in some hypertensive patients.

Patterns of hypertension management in Italy: results of a pharmacoepidemiological survey on antihypertensive therapy. Scientific Committee of the Italian Pharmacoepidemiological Survey on Antihypertensive Therapy.

OBJECTIVE: To collect statistically significant information on patterns of antihypertensive therapy in medical practice, with particular attention to the drugs used in the pharmacological management of hypertensive patients and the reasons for the limited achievement of therapeutic goals during treatment DESIGN: A survey conducted among general practitioners, specialists, and hypertensive patients. METHODS: A total of 28,000 physicians were contacted by letter and 3,394 declared their willingness to participate and received a questionnaire. Subsequently, 1,255 questionnaires suitable for analysis (corresponding to 37.0% of adhering physicians) were received. In addition, 4,612 questionnaires completed by patients were pooled and evaluated. The prevalence of hypertension was calculated from a base of 254,192 patients, seen by general practitioners. RESULTS: The prevalence of hypertension, defined as systolic blood pressure > or = 160 mmHg or diastolic blood pressure > or = 95 mmHg, or current treatment, was 19.7%. The average number of hypertensive patients in each general practitioner's file, covering the previous 12 months, was approximately 230. Physicians reported a 66% rate of discontinuation of treatment or switching to another drug. Physicians and patients both considered inadequate blood pressure control and side effects to be the two main reasons for switching antihypertensive therapy, but in opposite order. Furthermore, physicians indicated a prevalence of drug side effects between 10 and 20%, according to class of drug used, whereas 69% of patients reported to have experienced side effects. In the doctors' opinions, there were many reasons for poor patient adherence: complexity of the drug regimen, appearance of side effects, forgetfulness, reduced patient understanding of the need for long-term continuation of treatment, and refusal to accept a chronic pathological condition. CONCLUSIONS: The survey showed awareness of the disease among physicians and provides a representation of the experiences of both general practitioners and specialists, in addition to that of their patients. During antihypertensive therapy, a disconcerting degree of discontinuation and switching of drugs occurred. Insufficient blood pressure control and side effects accounted for most of the observed treatment changes. This survey revealed the existence of a gap between the physicians' perception of tolerability and the real experience of patients, a clear need for greater tolerability of treatments, and a need for an enhancement of patient-physician communication.

Urinary kallikrein excretion and blood pressure response to angiotensin converting enzyme inhibitors and calcium antagonists in hypertensive patients.

OBJECTIVE: To investigate whether the hypotensive effects of angiotensin converting enzyme (ACE) inhibitors in comparison with those of calcium antagonist might be predicted by urinary kallikrein activity, a marker of the activity of the renal kallikrein-kinin system. DESIGN: Seventy-five essential hypertensive patients were randomly assigned to treatment with ACE inhibitors (enalapril or lisinopril 20 mg once a day) or with calcium antagonists (nifedipine 20 mg twice a day or lacidipine 4 mg once a day). Fifty-four had normal (NK) and 21 low (LK) kallikrein activity. Blood pressure was measured after 2 weeks, and 3 and 6 months. Patients whose diagnostic blood pressure, 2 weeks after the first dose, decreased by at least 15 mmHg or was < or = 90 mmHg were defined as responders. The others were defined as non-responders. In non-responders a second drug was added and the patients were not considered for further analysis. METHODS: Urinary kallikrein activity was determined by a spectrophotometric assay using a synthetic chromogenic substrate. RESULTS: After 2 weeks therapy with ACE inhibitors 88% of NK patients were responders, whereas in the LK subgroup 40% were responders, a significant difference between subgroups. For the patients treated with calcium antagonists, conversely, 59% of NK patients were responders in comparison with 82% of the LK subgroup, a significant difference between drug groups. After 3 and 6 months of treatment blood pressure was significantly lower in NK patients treated with ACE inhibitors and in LK patients treated with calcium antagonists. In the NK group on ACE inhibitors the mean arterial pressure after the first dose was significantly related to that observed after 6 months (n = 0.71, P < 0.01). CONCLUSIONS: Our data indicate that urinary kallikrein activity may represent an index to predict the chronic antihypertensive effect not only of ACE inhibition but also of calcium antagonism, and support the concept that the renal kallikrein-kinin system might play some contributory role in modulating the hypotensive action of ACE inhibitors.

A novel promoter variant of the natriuretic peptide clearance receptor gene is associated with lower atrial natriuretic peptide and higher blood pressure in obese hypertensives.

OBJECTIVE AND DESIGN: The clearance receptor for natriuretic peptides (NPRC), a candidate gene for essential hypertension, is highly expressed in adipose tissue, where is nutritionally regulated. The objectives of the present study were to sequence the human 5'-flanking regulatory region of NPRC, to identify allelic variants and their frequencies, and to study the genotype/phenotype correlation in hypertensive patients. METHODS AND RESULTS: Using polymerase chain reaction (PCR) and direct automated sequencing, a biallelic (A/C) polymorphism was detected at position -55 in a conserved promoter element named P1. The novel C(-55) variant makes the promoter sequence identical to the mouse gene and introduces a second Hgal site in the amplified DNA, allowing the genotyping of a large number of subjects. In a random sample of 232 white Caucasians the C(-55) allele was more commonly found (81.7% of all alleles) with 155 CC (66.8%), 69 AC (29.7%) and only eight AA (3.5%) genotypes. Atrial natriuretic peptide (ANP) levels were determined in 84 patients with essential hypertension. In the presence of obesity (body mass index (BMI) > or = 30 kg/m2) the homozygous CC hypertensives (n = 21) had significantly lower plasma ANP (33.6 +/- 11.1 pg/ml) compared with the AC patients (n = 11; 46.8 +/- 15.9 pg/ml; P = 0.01), whereas systolic blood pressure (SBP) and mean blood pressure (MBP) had the opposite association (SBP 163.9 +/- 18.7 versus 150.9 +/- 12.9 and MBP 123.3 +/- 12 versus 114.5 +/- 5.9 mmHg; P< 0.05). The difference in ANP levels were also present when overweight patients (BMI > or = 27 kg/m2) were considered. CONCLUSION: A common 'ancestral' C(-55) variant of the NPRC P1 promoter is associated with lower ANP levels and higher SBP and MBP in obese hypertensives. The C(-55) variant, in the presence of increased adiposity, might reduce plasma ANP through increased NPRC-mediated ANP clearance, contributing to higher blood pressure.

The effects of aprotinin, a kallikrein inhibitor, on renin release and urinary sodium excretion in mild essential hypertensives.

The effects of aprotinin on renin release and renal function were evaluated in 24 male essential hypertensive patients, on unrestricted (n = 17) and on chronic low as well as on high sodium intake. Aprotinin (1 X 10(6) kallikrein inhibitor units) or saline (200 ml) were infused in all patients for 6 h. Blood samples were taken for plasma renin activity (PRA) and 6-h urine collections were obtained for active and inactive kallikrein, sodium and potassium excretion measurement. In patients on unrestricted sodium diet, aprotinin had no effect on blood pressure (BP), glomerular filtration rate, renal plasma flow, urinary sodium and potassium excretion. However, an inverse relationship was found between pretreatment urinary sodium excretion and the per cent reduction of the latter after aprotinin. A significant reduction in urinary sodium excretion was induced by aprotinin in patients on high sodium intake, whereas no change was observed in the same patients when on a low sodium diet. Aprotinin reduced the urinary excretion of active kallikrein by 81% and the active to total kallikrein ratio from 24 to 6%. Infusion of aprotinin induced a significant decline in active renin but did not modify inactive renin levels in patients on unrestricted sodium diet as well as in patients on low or high sodium intake. Our data suggest that the inhibition of kallikrein and/or other serine proteases by aprotinin can interfere with renal release of active renin and also support the hypothesis that the renal kallikrein system exerts a regulatory control on sodium excretion in salt replete hypertensives.

High levels of plasma atrial natriuretic factor and impaired left ventricular diastolic function in hypertensives without left ventricular hypertrophy.

OBJECTIVE: To seek possible correlations between plasma atrial natriuretic factor (ANF) and left ventricular diastolic function (LVDF) in hypertensive patients. DESIGN: Since LVDF abnormalities can be detected in patients with normal left ventricular mass, we studied a group of hypertensive patients without left ventricular hypertrophy. METHODS: Untreated hypertensive patients (n = 23) and normotensive control subjects (n = 19) were studied. LVDF indices were obtained by M-mode and pulsed Doppler echocardiography. Blood samples for plasma ANF were taken in the recumbent position from subjects on normal-sodium intake. RESULTS: Plasma ANF levels were significantly higher in hypertensive patients than in normotensive subjects. All indices for systolic function were normal in both normotensive subjects and hypertensive patients. Left atrial diameter was significantly higher for hypertensive patients than for normotensive subjects. Considering LVDF, all indices for ventricular filling were found to be altered, on average, in hypertensive patients, the only exception being peak early velocity. In addition, significant correlations were found between plasma ANF and the pulsed Doppler parameters of left ventricular filling, peak atrial velocity and the peak early:peak atrial velocity ratio. Overall correlations between plasma ANF and left atrial diameter, and between left atrial diameter and left ventricular mass index were also observed. CONCLUSIONS: The high levels of plasma ANF observed in our hypertensive patients and their correlation with the LVDF indices (which mainly reflect the atrial contribution to ventricular filling) could be the result of an increased atrial stretch due to diastolic ventricular dysfunction. This may exist in hypertensive patients before the development of ventricular hypertrophy.

Plasma atrial natriuretic peptide and natriuretic peptide receptor gene expression in adipose tissue of normotensive and hypertensive obese patients.

OBJECTIVE: Human and rat adipose tissue contain very high levels of natriuretic peptides clearance receptor messenger (m)RNA, and fasting inhibits its gene expression in adipose tissue. In this study we evaluated plasma atrial natriuretic peptide (ANP) and gene expression of biologically active type A natriuretic peptide receptor (NPr-A) and clearance natriuretic peptide receptor (NPr-C) in adipose tissue of obese hypertensive and obese normotensive patients. DESIGN AND METHODS: We studied 27 untreated obese hypertensives, 26 obese normotensives (body mass index > or = 30 kg/m2), 24 non-obese essential hypertensives and 23 lean healthy subjects (body mass index < or = 25 kg/m2). Blood samples were withdrawn for ANP, plasma renin activity and aldosterone radioimmunoassays. Subcutaneous peri-umbilical adipose tissue samples were obtained, by needle aspiration, in 13 obese hypertensives and in 12 obese normotensives and used for RNA extraction. Then, complementary synthesis and semiquantitative polymerase chain reaction (PCR) with primers complementary to sequences of different exons of the genes encoding for NPr-A, NPr-C and beta-actin, were performed. 32P-labeled PCR products were separated by electrophoresis, blotted onto nylon membranes, and the exposed autoradiographic films were analysed by densitometry. NPr signals were normalized by the beta-actin expression level. RESULTS: Plasma ANP was lower in obese hypertensives than in obese normotensives (37.5+/-7 versus 43.2+/-6 pg/ml, P< 0.05), but was higher in non-obese hypertensives than in non-obese normotensives. In contrast, plasma renin activity and aldosterone were higher in the obese hypertensives. Although NPr-A and NPr-C expression were not statistically different between the two obese groups, the NPr-A: NPr-C mRNA ratios were significantly lower in obese hypertensives (P < 0.03). CONCLUSIONS: Our data suggest that in obese hypertensives compared to obese normotensives, the lower NPr-A: NPr-C ratio might determine decreased biological activity and/or an increased clearance of natriuretic peptide in adipose tissue, suggesting that the natriuretic peptide and its receptor system may be important in obesity-related hypertension where ANP levels are lower.

Angiotensin converting enzyme gene polymorphism and carotid atherosclerosis in a low-risk population.

OBJECTIVES: Angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism has been shown to be an independent risk factor for myocardial infarction and other cardiovascular diseases. The aim of the study was to investigate the relationship between ACE genotype and carotid atherosclerosis evaluated by ultrasonography. PATIENTS AND METHODS: ACE I/D polymorphism was determined in 240 low-risk patients (mean age 53.6 +/- 7 years) in relation to traditional risk factors and the degree of carotid atherosclerosis. Intimal-medial thickness was measured at the level of the common carotid artery, bifurcation and internal carotid on both sides. Patients were defined as normal (n = 47, intimal-medial thickness <1.0 mm), thickened (n = 56, intimal-medial thickness > or = 1.0 and < or = 1.3 mm in the thickest wall) or with an atherosclerotic plaque (n = 137, intimal-medial thickness >1.3 mm for at least one level of examination). Age, sex, body mass index, blood pressure levels and prevalence of other risk factors were similar in the three groups. I/D polymorphism was determined by polymerase chain reaction using specific primers and genomic DNA from leukocytes as template. Plasma ACE levels, plasma renin activity and plasma aldosterone were evaluated in all patients by standard procedures. RESULTS: No significant differences were found in humoral parameters, ACE, genotype distribution and the corresponding allele frequency among the three groups of patients. Only ACE plasma levels were significantly higher in the DD and ID genotypes compared with the II genotype (DD 14.27 +/- 5.05 IU/ml, ID 12.70 +/- 4.31 IU/ml; II 8.04 +/- 3.45 IU/ml). The mean intimal-medial thickness was similar in all three genotypes. CONCLUSION: Although ACE genotype has been shown to be related to coronary atherosclerosis, the present data do not indicate that the DD genotype is associated with carotid atherosclerosis. However, further studies of larger populations are needed to clarify whether genetic ACE polymorphism is associated with carotid atherosclerosis.

Fasting inhibits natriuretic peptides clearance receptor expression in rat adipose tissue.

OBJECTIVE AND DESIGN: The early phase of weight loss induced by fasting is associated with diuresis, natriuresis and reduction in blood pressure through unclear mechanisms. Atrial natriuretic peptide (ANP) is a cardiac hormone with potent natriuretic, diuretic and hypotensive effects mediated by 'biologically active' receptors (NPr-A). A second type of receptor mediates the clearance of ANP (the clearance receptor, NPr-C). Since NPr-C appears to be abundant in adipose tissue, we analysed NPr-C and NPr-A gene expression in white and brown adipose tissue (WAT and BAT) as well as in renal cortex of fasting rats. Plasma ANP, cyclic GMP and aldosterone were also measured. METHODS: Twelve male Wistar rats were deprived of food for about 50 h, and 12 other rats were fed ad libitum. Periepididymal WAT, interscapular BAT and left renal cortex were used for RNA extraction and northern blot analysis with rat NPr-C and NPr-A complementary DNA probes labelled with 32P-dCTP. Densitometric analysis of hybridization signals was corrected by beta actin expression before statistical analysis. Blood was drawn for ANP, cyclic GMP (cGMP) and aldosterone radioimmunoassays, which were also measured in a group of six rats deprived of food for 25 h. RESULTS: A dramatic decrease in NPr-C steady-state messenger RNA levels was observed both in WAT (about 3.6-fold, P < 0.001) and in BAT (about threefold, P < 0.01), but fasting did not affect the expression of NPr-A in adipose tissues. In the renal cortex NPr-C and NPr-A messenger RNA levels were unaffected by fasting. ANP and aldosterone levels were reduced after fasting whereas cyclic GMP was increased at 25 h, but the differences did not reach statistical significance. CONCLUSIONS: Fasting exerts a tissue-specific and gene-specific suppression of NPr-C gene expression in adipose tissue that appears to be accompanied by an increased biological activity of ANP. The natriuresis and diuresis and reduction of blood pressure induced by fasting might result from a reduced expression of NPr-C in adipose fat pads.

Cardiovascular phenotype of young adults and angiotensinogen alleles.

OBJECTIVES AND DESIGN: Angiotensinogen (AGT) gene variants influence angiotensinogen plasma levels in children and young adults. The angiotensinogen promoter (-6)A variant facilitates gene transcription in human tissues and it has been associated with high blood pressure in older adults. A young adult population can be used as a model to study genotype/phenotype associations between AGT (-6) variants and cardiovascular variables. METHODS AND RESULTS: Anthropometric measurements, blood pressure and heart rate were taken in 422 white Caucasian students (mean age 23.5 years, SD 2.5 years). Family history for hypertension, physical activity and smoking history were evaluated. Left ventricular variables were measured by echocardiography. Carotid artery wall intimal-media thickness (IMT) was measured by high resolution sonography and digitalized morphometry. The AGT G(-6)A alleles were evaluated by mutagenically separated polymerase chain reaction controlled by direct sequencing. No significant associations were found between angiotensinogen genotype and blood pressure, cardiac variables [except for deceleration time in females which increased with the number of (-6)A alleles] and IMT. Allele frequencies were similar between the first and third tertile of blood pressure and left ventricular mass, and were also similar between negative or positive family history for hypertension (the last group having significantly higher systolic blood pressure in males, P = 0.04 and diastolic blood pressure in females, P < 0.01). Moreover, no relevant interaction on the cardiovascular variables was found between AGT genotype and body mass index. CONCLUSIONS: The angiotensinogen G(-6)A variants do not affect cardiovascular parameters in young adults, but an effect of this polymorphism on cardiovascular phenotype (and hypertension) in older adults cannot be excluded. Additional factors, associated with ageing, should be present to unleash the supposed unfavourable potential of the (-6)A angiotensinogen variant.

Long-term effects of indapamide: final results of a two-year Italian multicenter study in systemic hypertension.

To evaluate the antihypertensive efficacy and tolerability of a low-dose diuretic, indapamide, 2.5 mg once daily, was given to 248 patients with uncomplicated, mild to moderate hypertension for a period of 24 months. Blood pressure during sitting was 165 +/- 1/105 +/- 1 mmHg (mean +/- standard error of the mean) at the end of the placebo run-in period and 143 +/- 1/88 +/- 1 and 140 +/- 1/85 +/- 1 mmHg after 2 and 24 months, respectively; heart rate was clinically unmodified (from 77 +/- 1 to 75 +/- 1 beats/min). Total cholesterol, high-density cholesterol and serum triglycerides were unchanged, and uric acid increased significantly (from 292.0 +/- 6.5 to 377.7 +/- 56.5 mumols/liter). A mild reduction in serum potassium (-0.36 +/- 0.03 mmol/liter) was observed after 2 and 6 months of therapy; however, the degree of reduction appeared to be lower than that from reported studies with other thiazide diuretics. The incidence of hypokalemia (serum potassium less than 3.5 mmol/liter) was highest in northern Italy (17%), intermediate in the central region (14%) and lowest in southern Italy (2%), although the absolute reduction in serum potassium was similar in all the geographic areas. Blood glucose tolerance was unchanged despite the changes in serum potassium. The tolerability was good on the whole, with a tendency toward an improvement in the well-being of patients, most of whom were already asymptomatic before starting the study.