Renin-angiotensin system, natriuretic peptides, obesity, metabolic syndrome, and hypertension: an integrated view in humans.

The obesity pandemic is closely related to hypertension and metabolic syndrome. Visceral adipose tissue plays a key role in the metabolic and cardiovascular complications of being overweight. The pathophysiological link between visceral adiposity and cardiometabolic complications focuses on insulin sensitivity, sympathetic nervous system, renin-angiotensin-aldosterone system (RAAS) and, only recently, on cardiac natriuretic peptide system (CNPS). RAAS and CNPS are endogenous antagonistic systems on sodium balance, cardiovascular system, and metabolism. The circulating RAAS is dysregulated in obese patients, and adipose tissue has a full local renin-angiotensin system that is active at local and systemic level. Adipocyte biology and metabolism are influenced by local renin-angiotensin system, with angiotensin II acting as a 'growth factor' for adipocytes. CNPS induces natriuresis and diuresis, reduces blood pressure, and, moreover, has powerful lipolytic and lipomobilizing activity in humans but not in rodents. In obesity, lower plasmatic natriuretic peptides levels with increasing BMI, waist circumference, and metabolic syndrome have been documented. Thus, reduced CNPS effects coupled with increased RAAS activity have a central role in obesity and its deadly complications. We propose herein an integrated view of the dysregulation of these two antagonistic systems in human obesity complicated with hypertension, metabolic syndrome, and increased cardiovascular risk.

A human fatty acid amide hydrolase (FAAH) functional gene variant is associated with lower blood pressure in young males.

BACKGROUND: Fatty acid amide hydrolase (FAAH) inhibitors, preventing endocannabinoid (EC) degradation, reduce blood pressure (BP) and heart rate in young male (YM) hypertensive rodents. The functional human FAAH 129T gene variant results in reduced protein level and enzymatic activity but its relationship with BP is unknown. This study investigates the relationship among FAAH P129T alleles and cardiovascular features in YMs at baseline and after 9-year follow-up, and in older male obese hypertensive (OH) patients, in whom the EC system (ECS) is overactive. METHODS: Genotype analysis was performed in 215 Caucasian male students (24 (0.2) years old) and in 185 older OH patients (50 (0.2) years old). YMs were also followed up for 9 years. Clinical and anthropometric variables, BP, cardiac and carotid artery echographic measurements were evaluated. RESULTS: YMs with the FAAH 129T allele had lower systolic (P = 0.042) and mean BP (P = 0.022), and a trend toward lower diastolic BP (P = 0.06). Such significant association was maintained at follow-up. In contrast, the same allele was not associated with BP in older OH. No association was found with other cardiac and vascular variables. CONCLUSION: An FAAH defective gene variant results in lower BP in YMs, similar to the findings in young rodents. This effect is lost in older OH patients. Because cannabinoid CB1 receptor blockade is associated with BP reduction in OH patients, EC effects and the use of ECS-interfering drugs is likely to be age and clinical-condition dependent.

The 212A variant of the APJ receptor gene for the endogenous inotrope apelin is associated with slower heart failure progression in idiopathic dilated cardiomyopathy.

BACKGROUND: Idiopathic dilated cardiomyopathy (IDC) has multiple genetic and acquired causes. Apelin is an endogenous peptide that increases cardiac inotropism through his APJ receptor. No data are available concerning the APJ gene mutations responsible for IDC or on the role of APJ receptor gene variants in predicting heart failure (HF) progression. METHODS AND RESULTS: We prospectively evaluated 202 consecutive patients with IDC and 202 matched controls: 90 were screened for APJ gene mutations and all 202 were genotyped for G212A and A445C APJ receptor polymorphisms. No mutations were found within the coding or untranslated regions of the APJ receptor, and no differences in allelic or genotype frequencies were observed comparing patients with a healthy control population. The correlations between APJ receptor polymorphisms and HF progression were assessed. During a median follow-up of 37 months, 35 patients experienced HF progression. Univariate analysis showed that patients carrying at least 1 copy of 212A had a significantly lower risk for HF-related events than those who were homozygous for the G212 variant, and multivariate analysis confirmed that it was significantly related to a more favorable prognosis. CONCLUSIONS: APJ is unlikely to be a gene causing IDC, but the independent correlation between the 212A allele and a better prognosis suggests that it might act as a modifier gene.

The functional HERG variant 897T is associated with Conn's adenoma.

OBJECTIVE: Aldosterone secreting adenomas (aldosteronomas) have an unknown molecular origin. Ion channel currents are involved in signal transduction leading to aldosterone synthesis and secretion. HERG (human-ether-a-go-go-related gene) encodes for a potassium channel responsible for the outward rectifying delayed current and it is mutation prone. When mutated it causes most of the familial forms of both long QT and short QT syndromes. Abnormal repolarization in glomerulosa cells might increase aldosterone secretion or induce a proliferative advantage. The aims of this study were to: (1) evaluate HERG expression in aldosteronomas; (2) search for HERG somatic mutations; and (3) determine whether there is any relationship between the common HERG functional variant (A2690C, leading from lysine 897 to threonine, K897T) and aldosteronoma. DESIGN AND METHODS: Aldosteronoma and blood samples from 17 patients were studied to evaluate HERG expression, full-length HERG complementary DNA sequencing, and genotyping for K897T alleles. The prevalence of HERG 897 alleles was also tested in a control population and a population consisting entirely of hypertensive individuals. RESULTS: HERG was expressed in all aldosteronomas analysed. HERG somatic mutations were not detected. The 897T variant of HERG was significantly more common among patients with aldosteronoma (897T allele 41%) than in patients with moderate-severe essential hypertension (897T allele 20%, P = 0.007) or in the control population (897T allele 12%, P < 0.0001). The 897T/T genotype was present in 24% of the aldosteronoma patients versus 7% (P = 0.040) and 3% (P = 0.001) in essential hypertension and in the control population, respectively. When the chi test was performed considering the three groups together, the significance was similar (for alleles P < 0.0001 and for genotypes P = 0.004). CONCLUSION: The common functional HERG variant 897T may predispose to the development of aldosteronoma.

The 460Trp allele of alpha-adducin increases carotid intima-media thickness in young adult males.

BACKGROUND: The 460Trp allele of the alpha-adducin gene (ADD1), which is involved in a form of salt-sensitive hypertension, has been associated with patterns of target organ damage. OBJECTIVES: As carotid artery intima-media thickness (IMT) largely depends upon unknown genetic factors, besides being associated to conventional risk factors, we tested the association of the 460Trp allele of ADD1 with IMT in a well-characterized sample of young healthy normotensive subjects, to assess the role of ADD1 polymorphism without overlapping effects of age or already elevated blood pressure. METHODS: Anthropometric measurements, blood pressure (BP), and carotid artery wall IMT (high-resolution sonography and digitalized morphometry) were obtained in 420 healthy normotensive Caucasian university students. Genotypes for ADD1 were detected by automated genomic polymerase chain reaction (PCR). RESULTS: ADD1 genotypes were evenly distributed between genders. IMT was significantly larger in carriers of the 460Trp allele of ADD1, while a significant gender x ADD1 interaction (P = 0.02) demonstrated that IMT was increased only in males carrying the 460Trp allele (P < 0.001). No significant association was found in females. CONCLUSIONS: The 460Trp allele of ADD1 contributes substantially to increase carotid IMT, in a male hormonal milieu only, at least in the young age range.

Allelic variants of natriuretic peptide receptor genes are associated with family history of hypertension and cardiovascular phenotype.

OBJECTIVE: Abnormalities in the natriuretic peptide system could play a key role in the genesis of hypertension. We evaluated the associations between a family history of hypertension, cardiovascular phenotype and allelic variants of Npr1 and Npr3, two candidate genes that codify for natriuretic peptide receptors. METHODS: We genotyped 45 young normotensive subjects (19 males, 26.8 +/- 3.7 years) with accurately assessed family history of hypertension (FH+) and 52 (26 males, 26.1 +/- 3.1 years) without (FH-) for the known variants of Npr1 and Npr3 genes, and for a novel length difference (3C/4C) polymorphism at position 15129 in the 3'-untranslated region of the Npr1 gene. Blood pressure, echocardiography and plasma brain natriuretic peptide were assessed. RESULTS: Both the novel Npr1 3C allele (59 versus 33%, P < 0.001) and the 3C/3C genotype (31 versus 8%; P < 0.001) were significantly more frequent in FH+ than in FH-. The inverse distribution of the 4C/4C genotype suggested that a casual association was very unlikely. Moreover, the 3C/3C homozygous had significantly higher systolic blood pressure (121.1 +/- 6.3 versus 115.6 +/- 7.8 mmHg in 4C/4C; P < 0.05) and a longer left ventricular isovolumic relaxation time (67 +/- 10 versus 61 +/- 9 ms; P < 0.05). The Npr3 C(-55) allele variant was also more frequent in FH+ (88 versus 76%, P < 0.05), but was not associated with the cardiovascular phenotype. CONCLUSIONS: The novel Npr1 gene 3C variant and the Npr3 gene C(-55) allele are associated with hypertensive family history. Moreover, the functional Npr1 3C variant, when homozygous, is also associated with higher systolic blood pressure and prolonged ventricular relaxation.

Tolerability of long-term treatment with lercanidipine versus amlodipine and lacidipine in elderly hypertensives.

BACKGROUND: Irrespective of their clinical relevance, side effects cannot be considered a negligible problem in antihypertensive therapy. The aim of this trial was to evaluate the tolerability profile of lercanidipine with that of two other calcium antagonists (amlodipine and lacidipine) in elderly hypertensives. METHODS: In a multicenter, double-blind, parallel study 828 elderly (aged > or =60 years) hypertensives were randomized to lercanidipine 10 mg/day (n = 420), amlodipine 5 mg/day (n = 200), or lacidipine 2 mg/day (n = 208) (ratio 2:1:1). If blood pressure (BP) control was unsatisfactory (systolic BP/diastolic BP > or =140/90 mm Hg), the dose of the double-blind medication was doubled and, as a further step, enalapril or atenolol (plus diuretic, if needed) was added. Patients were treated for an average of 12 months. RESULTS: Amlodipine patients had significantly (P <.001) higher rates of edema (19%) and of early study discontinuations due to edema (8.5%) compared with lercanidipine (9% and 2.1%) and lacidipine patients (4% and 1.4%). Similarly, edema-related symptoms (lower limb swelling and heaviness) occurred significantly (P <.01) more often with amlodipine (50% and 45%, respectively) than with lercanidipine (35% and 33%) and lacidipine (34% and 31%). Most edema cases occurred in the first 6 months, a between-treatment difference being evident since beginning of treatment. Other drug-related adverse events did not differ between treatments. Blood pressure was equally and effectively reduced in the three groups. CONCLUSIONS: The two lipophilic dihydropyridine calcium antagonists, lercanidipine and lacidipine, have an antihypertensive effect comparable to that of amlodipine, but a better tolerability profile.

[Natriuretic peptides and essential arterial hypertension]. / Peptidi natriuretici e ipertensione arteriosa essenziale.

Natriuretic peptide system plays a well-defined role in the regulation of blood pressure and fluid volume. Although the effects of natriuretic peptides (atrial natriuretic peptide, brain natriuretic peptide and C-type natriuretic peptide) are mediated by specific biologic receptors, their plasma level is influenced by clearance receptors. It has been demonstrated that in hypertensive subjects plasma levels of natriuretic peptides are impaired; furthermore peptide receptor polymorphisms have been shown to be significantly associated with hypertension and cardiac hypertrophy. Studying normotensive subjects at high genetic risk of developing hypertension on the basis of family history makes it possible to investigate the role of natriuretic peptide system in the genesis of hypertension. It has been shown that plasma atrial and ventricular natriuretic peptide levels are significantly reduced in normotensive subjects with a family history of hypertension. Our study is the first one showing association among positive family history of essential hypertension and natriuretic peptide receptor polymorphisms. We identified a novel insertion/deletion polymorphism at position 15,129 in the 3'-untranslated region (3'-UTR) of NPRA receptor mRNA. The NPRA gene deletion variant is associated with hypertensive family history and higher systolic blood pressure. The "deletion 15129" variant might participate in the functional impairment of natriuretic peptide system defining an increased genetic susceptibility to hypertension.

Hypertension and obesity after the menopause.

It is well known that in pre-menopausal women the incidence of cardiovascular events is lower than in men of the same age and that after the menopause cardiovascular morbidity and mortality in women become similar, if not higher, than that in men indicating that female sex hormones play a relevant protective role upon the vasculature. Among the cardiovascular risk factors, hypertension appears to be more prevalent in postmenopausal women than in men but the precise mechanism through which menopause favours the development of hypertension is still a matter of debate. The prevalence of obesity and being overweight is also higher in postmenopausal women than that in men of comparable age. The pathogenesis of obesity-related hypertension recognizes a multifactorial mechanism including overactivity of the sympathetic nervous system, insulin resistance, leptin resistance, overactivity of the renin-angiotensin-aldosterone system and, finally, a blunted biological activity of the natriuretic peptides. The latter mechanism has been investigated by our group in recent years. Adipose tissue has been shown to express large amounts of mRNA for the biologically inactive C-type natriuretic peptide receptor (NPr-C) and this expression is decreased by fasting. Accordingly, adipose tissue can participate in the development and maintenance of high blood pressure through a reduced bioavailability of circulating natriuretic peptides leading to sodium retention. Since being overweight and obesity are a common finding in postmenopausal women, the complex mechanism of obesity-related hypertension can play a relevant role in explaining the high prevalence of hypertension after the menopause.

The association of left ventricular hypertrophy with metabolic syndrome is dependent on body mass index in hypertensive overweight or obese patients.

BACKGROUND: Overweight (Ow) and obesity (Ob) influence blood pressure (BP) and left ventricular hypertrophy (LVH). It is unclear whether the presence of metabolic syndrome (MetS) independently affects echocardiographic parameters in hypertension. METHODS: 380 Ow/Ob essential hypertensive patients (age ≤ 65 years) presenting for referred BP control-related problems. MetS was defined according to NCEP III/ATP with AHA modifications and LVH as LVM/h(2.7) ≥ 49.2 g/m(2.7) in males and ≥ 46.7 g/m(2.7) in females. Treatment intensity score (TIS) was used to control for BP treatment as previously reported. RESULTS: Hypertensive patients with MetS had significantly higher BMI, systolic and mean BP, interventricular septum and relative wall thickness and lower ejection fraction than those without MetS. LVM/h(2.7) was significantly higher in MetS patients (59.14 ± 14.97 vs. 55.33 ± 14.69 g/m(2.7); p = 0.022). Hypertensive patients with MetS had a 2.3-fold higher risk to have LVH/h(2.7) after adjustment for age, SBP and TIS (OR 2.34; 95%CI 1.40-3.92; p = 0.001), but MetS lost its independent relationship with LVH when BMI was included in the model. CONCLUSIONS: In Ow/Ob hypertensive patients MetS maintains its role of risk factor for LVH independently of age, SBP, and TIS, resulting in a useful predictor of target organ damage in clinical practice. However, MetS loses its independent relationship when BMI is taken into account, suggesting that the effects on MetS on LV parameters are mainly driven by the degree of adiposity.

Microalbuminuria and left ventricular mass in overweight and obese hypertensive patients: role of the metabolic syndrome.

BACKGROUND: Left ventricular hypertrophy (LVH) and microalbuminuria are common in hypertensive patients and are often associated with metabolic syndrome (MetS). However, it is not clear whether MetS could modify the association between cardiac and renal damage. OBJECTIVE: The aim of this study was to assess if the relationship of albumin/creatinine ratio (ACR) and left ventricular mass (LVM) could be independent from MetS in hypertensive overweight/obese patients. METHODS: 180 essential hypertensive and overweight/obese (body mass index [BMI] ≥25 kg/m(2)) patients referred to our Hypertension Centre from January 2006 to April 2009 because of blood pressure (BP) control-related problems were studied. Exclusion criteria were scarce adherence to antihypertensive drug therapy as investigated by the Morisky Medical Adherence Scale (MMAS), heart failure (New York Heart Association III or IV or left ventricular ejection fraction [LVEF] <50%), liver failure, cancer or other systemic severe diseases. MetS was defined according to the National Cholesterol Education Program (USA) Adult Treatment Panel III classification as modified by the American Heart Association. ACR was obtained from first morning urine specimens. Left ventricular dimensions, mass and ejection fraction, were measured by echocardiography following the American Society of Echocardiography recommendations. RESULTS: Patients with microalbuminuria had a 6-fold higher risk for LVH/h(2.7) and 2-fold higher risk for LVH/body surface area (BSA). Univariate linear regression analysis showed a positive relationship between ACR and LVM, expressed both as LVM/h(2.7) or LVM/BSA, as well as a direct correlation between logACR and interventricular diameters and ejection fraction. Regression models including logACR, estimated glomerular filtration rate, BMI, age, hypertension duration, smoking and MetS (as a single variable as well as each single component), showed that only logACR, BMI, hypertension duration and systolic blood pressure (SBP) were independently associated with LVM/h(2.7). CONCLUSION: Along with BP and BMI, albuminuria measured in a morning urine sample as ACR is a valuable low-cost index of cardiac organ damage and increased cardiovascular risk in hypertensive patients independently by MetS. On the other hand, MetS is not an independent risk factor for cardiac damage because it does not seem to add anything more than the sum of each of its components (especially SBP and adiposity indexed by BMI) to the relationship between cardiac and renal subclinical organ damage.

Cannabinoid CB1 receptor expression in relation to visceral adipose depots, endocannabinoid levels, microvascular damage, and the presence of the Cnr1 A3813G variant in humans.

Dysregulation of the endocannabinoid system in the visceral adipose tissue (VAT) is associated with metabolic and cardiovascular complications of obesity. We studied perirenal VAT CB1 receptor expression in relation to anthropometry, VAT area and endocannabinoid levels, kidney microvascular damage (MVDa), and the presence of the CB1 gene A3813G variant, the frequency of which was also evaluated in a large population of obese-hypertensive (OH) patients with or without the metabolic syndrome (MetS). Perirenal VAT and kidney samples were obtained from 30 patients undergoing renal surgery. Total and perirenal VAT areas were determined by computed tomography. CB1 messenger RNA expression and endocannabinoid levels in perirenal VAT were determined by quantitative reverse transcriptase polymerase chain reaction and liquid chromatography-mass spectrometry, respectively. The MVDa was evaluated in healthy portions of kidney cortex. The A3813G alleles were identified by genotyping in these patients and in 280 nondiabetic OH patients (age

Altered pattern of cannabinoid type 1 receptor expression in adipose tissue of dysmetabolic and overweight patients.

In overweight patients (OW), the increased peripheral activity of the endocannabinoid system in visceral adipose tissue (VAT) may be mediated by cannabinoid type 1 (CB1) receptor expression. We determined whether CB1 receptor splice variants and messenger RNA (mRNA) levels in perirenal and subcutaneous adipose tissues are associated with obesity and metabolic syndrome (MetS). Gene expression with multiple-primers real-time polymerase chain reaction (TaqMan; Applied Biosystem, Weiterstadt, Germany) was performed to study VAT and paired subcutaneous adipose tissue (SAT) mRNA from 36 consecutive patients undergoing nephrectomy. Cannabinoid type 1A and CB1E mRNAs variants with the longer version of exon 4 were expressed. The CB1 expression in perirenal VAT significantly correlated with body mass index (BMI). Paired subcutaneous/perirenal samples from normal-weight patients (BMI < 25 kg/m(2)) showed higher CB1 expression in SAT (P = .002), whereas in OW (BMI > or = 25 kg/m(2)), the higher CB1 expression was in VAT (P = .038). In unpaired samples, SAT of normal-weight patients had significantly higher CB1 mRNA levels compared with SAT of OW, whereas higher CB1 expression (P = .009) was found in VAT of OW (n = 25). Overweight patients with increased visceral CB1 expression had higher waist circumference (P < .01), insulin (P < .01), and homeostasis model assessment index (P < .01). In addition, patients with the MetS (n = 22) showed higher CB1 expression in perirenal adipose tissues (P = .007). Visceral adipose CB1 expression correlated with BMI. Overweight patients and those with MetS showed a CB1 expression pattern supporting a CB1-mediated overactivity of the endocannabinoid system in human VAT.

A geriatric emergency service for acutely ill elderly patients: pattern of use and comparison with a conventional emergency department in Italy.

The current disease-oriented, episodic model of emergency care does not adequately address the complex needs of older adults presenting to emergency departments (EDs). Dedicated ED facilities with a specific organization (e.g., geriatric EDs (GEDs)) have been advocated. One of the few GED experiences in the world is described and its outcomes compared with those of a conventional ED (CED). In a secondary analysis of a prospective observational cohort of 200 acutely ill elderly patients presenting to two urban EDs in Ancona, Italy, identifiers and triage, clinical, and social data were collected and the following outcomes considered: early (30-day) and late (6-month) ED revisit, frequent ED return, hospital admission, and functional decline. Death, functional decline, any ED revisit and any hospital admission were also considered as a composite outcome. Odds ratios and 95% confidence intervals (CIs) were calculated. Overall, GED patients were older and frailer than CED patients. The two EDs did not differ in terms of early, late, or frequent ED return or in 6-month hospital admission or functional decline. The mortality rate was slightly but significantly lower in the GED patients (hazard ratio=0.47, 95% CI=0.22-0.99, P=.047). The data suggest noninferiority and, indirectly, a slight superiority for the GED system in the acute care of elderly people, supporting the hypothesis that ED facilities specially designed for older adults may provide better care.

A manual of guidelines to score the modified cumulative illness rating scale and its validation in acute hospitalized elderly patients.

OBJECTIVES: To update previous guidelines to score the Cumulative Illness Rating Scale (CIRS) and test their usefulness in hospitalized elderly patients. DESIGN: The CIRS was scored retrospectively in a cohort of elderly patients followed for 18 months. SETTING: An acute internal medicine ward in an academic tertiary care hospital. PARTICIPANTS: Three hundred eighty-seven patients aged 65 and older. MEASUREMENTS: The CIRS was retrospectively scored for the enrolled patients. Intrarater and interrater reliability were calculated. Two illness severity indices (total score (TSC) and severity (SV)) and one comorbidity index (CM) were obtained. Clinical features and comprehensive geriatric assessment (CGA) variables were also used. All patients underwent an 18-month follow-up for mortality and rehospitalization. RESULTS: Intrarater and interrater reliability of the CIRS scored following the guidelines was good (intraclass correlation coefficients of 0.83 and 0.81, respectively). The TSC, SV, and CM correlated with clinical features (laboratory values, medication usage, and length of in-hospital stay) and CGA variables (cognitive impairment, depression and disability). All three indices were able to predict 18-month mortality and rehospitalization rates. CONCLUSION: This study confirmed the validity of the CIRS as an indicator of health status and demonstrated its ability to predict 18-month mortality and rehospitalization in hospitalized elderly patients. The availability of detailed guidelines for scoring the CIRS can improve its usefulness and facilitate more-widespread use for research and clinical aims.

Treatment of isolated systolic hypertension: the SHELL study results.

OBJECTIVE: Our aim was to compare the effect of lacidipine and chlorthalidone on cardiovascular outcome as a primary parameter and blood pressure as a secondary in elderly patients with isolated systolic hypertension in a prospective study with an open design. METHODS: 1882 males and females outpatients > or = 60 years were randomly assigned to the administration of chlorthalidone 12.5 mg o.d. or lacidipine 4 mg o.d. Patients were recruited if sitting systolic blood pressure was > or = 160 mmHg with a diastolic blood pressure equal or lower than 95 mmHg. Primary endpoint was a composite of cardiovascular and cerebrovascular events. RESULTS: At randomization mean systolic blood pressure was 178.1 mmHg in the lacidipine and 178.2 mmHg in the chlorthalidone group, the corresponding mean diastolic values being 86.9 and 86.8 mmHg. In both lacidipine and chlorthalidone groups treatment caused a significant (p < 0.001) and marked systolic blood pressure reduction which was maintained throughout the treatment period with a significant (p < 0.001) and steady although less marked reduction in diastolic blood pressure as well. At the end of treatment period (median 32 months), the reduction was 36.8/8.1 mmHg (systolic/diastolic) in the chlorthalidone and 38.4/7.9 mmHg in the lacidipine group, the final on treatment blood pressures being 142.0/79.2 and 143.2/79.5 mmHg, respectively. Treatments were similarly effective in males and females and in age groups between 60 and 69 years (n = 763), 70 and 79 years (n = 744) and > or = 80 years (n = 375). Similar reductions were obtained in a subgroup of patients (n = 209) followed in double-blind fashion for 1 year. The overall incidence of the primary endpoints was 9.3% with no significant between-group difference. Total mortality was also similar between groups. CONCLUSIONS: In elderly patients with isolated systolic hypertension, administration of lacidipine or chlorthalidone markedly reduced systolic blood pressure with no difference in the incidence of cardiovascular events and total mortality.

Natriuretic peptide clearance receptor alleles and susceptibility to abdominal adiposity.

OBJECTIVE: To test the association of the C(-55)A polymorphism of the natriuretic peptide clearance receptor (NPRC) with blood pressure (BP), overweight/obesity, and body fat distribution in a large male adult population. RESEARCH METHODS AND PROCEDURES: The study population was from a cross-sectional and follow-up study of 787 untreated male participants in the 1994 to 1995 follow-up examination of the Olivetti Heart Study in Naples (356 of whom were examined previously in 1975). BP and anthropometric measures were taken, and biochemical assays were performed. The NPRC gene polymorphism C(-55)A was evaluated by polymerase chain reaction and HgaI digestion. RESULTS: In the whole study population, there was no difference in BP, BMI, and biochemical tests among genotypes. Considering an A(-55) recessive model of inheritance, the AA subjects had lower BMI and waist circumference and lower prevalence of overweight, obesity, and abdominal adiposity as compared with the CC+CA subjects. On reviewing the characteristics of the subgroup previously examined in 1975, the AA subjects had already lower BMI, and their 20-year rate of overweight and obesity was lower than the CC+CA subjects; no difference was observed in the rate of hypertension. DISCUSSION: Male subjects carrying the A(-55)A NPRC genotype had a significantly lower prevalence of overweight, obesity, and abdominal adiposity. They also had a lower 20-year rate of overweight compared with CC+CA individuals. These findings from a large unselected and untreated male population are in keeping with the recent evidence of a powerful lipolytic and lipomobilizing activity of natriuretic peptides.