| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Department of Molecular and Clinical Endocrinology and Oncology (T.C., L.T., A.C., G.L., F.O.), and Department of Clinical and Experimental Medicine (F.M.), University "Federico II," 80131 Naples, Italy; Department of Obstetrics and Gynecology (S.P.), University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy; MeriGen Laboratory of Molecular Biology (S.D.B., D.L.), 80131 Naples, Italy; and Department of Clinical Medicine (F.G., C.V.), Cardiovascular and Immunological Science, Cardiac Rehabilitation Unit, University "Federico II," 80131 Naples, Italy
Address all correspondence and requests for reprints to: Francesco Orio, M.D., Ph.D., Department of Molecular and Clinical Endocrinology and Oncology, University "Federico II" of Naples, Via S. Pansini 5, 80131 Naples, Italy. E-mail: francescoorio{at}virgilio.it.
 |
Abstract |
|---|
 Top Abstract IntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
Objective: Our objective was to investigate serum aldosterone levels in PCOS and correlate them to some CVR factors and early atherosclerotic markers.
Design and Setting: A prospective baseline-controlled clinical study was conducted at the University "Federico II" of Naples School of Medicine (Naples, Italy).
Patients: Fifty PCOS women age- and body mass index-matched with 50 healthy women were enrolled.
Mean Outcome Measures: Anthropometric, hormonal, and metabolic patterns, including plasma aldosterone, renin, and C-reactive protein, were measured in each subject. Intima-media thickness was also evaluated in each patient and control.
Results: Aldosterone levels were significantly increased (P < 0.001) in PCOS compared with healthy women (10.5 ± 3.2 vs. 5.7 ± 2.5 ng/dl). In PCOS, a significant (P < 0.001) direct correlation between plasma aldosterone and homeostasis model assessment, C-reactive protein, intima-media thickness, and mean blood pressure was found. On the other hand, high-density lipoprotein cholesterol and potassium were inversely (P < 0.001) related to serum aldosterone. Multiple linear regression analysis showed that the area under the curve for insulin and homeostasis model assessment was linearly related to aldosterone in PCOS.
Conclusion: PCOS women show an insulin resistance related increase in serum aldosterone levels.
|
Introduction |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
Aldosterone is a well-recognized CVR factor (8) with an important role in the pathophysiology of hypertension, left ventricular hypertrophy, and heart failure (9, 10).
It has been demonstrated that aldosterone promotes myocardial and vascular fibrosis, impairs arterial compliance and cardiac remodeling (11), and induces perivascular inflammation (12). The "primum movens" of these cardiovascular changes, which are provoked by aldosterone, could be the activation of an immunostimulatory state characterized by oxidative stress, inflammation, and a profibrogenic phenotype (13, 14). In this regard, a large body of evidence has shown a correlative and causative relationship between inflammation and IR (15, 16), and aldosterone could be involved in the pathogenesis of IR (17). In fact, elevated circulating aldosterone levels are associated with a high prevalence of glucose intolerance and diabetes (17, 18) and of the metabolic syndrome (19).
Based on these considerations, the present study was carried out to investigate serum aldosterone levels in PCOS women and the possible relationship between aldosterone and some CVR factors and early atherosclerotic markers related to PCOS.
|
Subjects and Methods |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
Subjects
Fifty patients with PCOS were consecutively enrolled in this study at the Department of Molecular and Clinical Endocrinology and Oncology in Naples, Italy. The diagnosis of PCOS was made according to the European Society for Human Reproduction (ESHRE) and American Society of Reproductive Medicine (ASRM) criteria for the PCOS diagnosis (20). In particular, PCOS was defined when two of the following criteria were found: oligo- and/or anovulation; clinical and/or biochemical signs of hyperandrogenism; polycystic ovaries (PCO); and exclusion of other etiologies (20). Exclusion criteria included pregnancy, hypothyroidism, hyperprolactinemia, Cushing’s syndrome, congenital adrenal hyperplasia, androgen-secreting tumors, or hypertension; current or previous (within the last 6 months) use of oral contraceptives, glucocorticoids, antiandrogens, ovulation induction agents, or antidiabetic, antiobesity, and antihypertensive drugs; or use of antiinflammatory drugs and other hormonal drugs during the last month. None of the patients were affected by neoplastic, metabolic, or cardiovascular disorders or other concurrent medical illness (including diabetes or kidney, liver, thyroid, autoimmune, cerebrovascular, and ischemic heart disease).
Fifty healthy women matched for age and body mass index (BMI) were enrolled and considered as the control group. The controls were defined as age- and BMI- matched with PCOS cases when the differences between cases and controls were less than 2 yr of age and 1 kg/m2 of BMI. The healthy state of the women in the control group was determined by medical history, physical and pelvic examination, and complete blood chemistry. Their normal ovulatory state was confirmed by transvaginal ultrasonography (TV-USG) and plasma progesterone (P) assay. Both procedures were performed during the luteal phase of the menstrual cycle (7 d before the expected menses). The presence of fluid in the cul-de-sac at TV-USG and a plasma P assay greater than 31.8 nmol/liter (>10 ng/ml) were considered criteria for occurred ovulation (21). Exclusion criteria for healthy controls were PCO at TV-USG and/or clinical or biochemical hyperandrogenism.
All subjects were nonsmokers and had normal oral glucose tolerance tests (OGTTs) (22) and normal physical activity; none drank alcoholic beverages or had a BMI less than 18 kg/m2.
Study protocol
At study entry, all subjects underwent venous blood sampling for a complete hormonal assessment, fasting glucose and insulin levels, lipid profile, C-reactive protein (CRP), serum sodium and potassium, plasma renin activity, and aldosterone values.
Before the study, all patients and control subjects were put on a regular salt diet containing 150 mmol of NaCl daily for 2 wk. All blood samples were obtained in the morning between 0800 and 0900 h after overnight fasting and resting in bed, during the early follicular phase (d 2–5) of a spontaneous or P-induced menstrual cycle. Aldosterone and renin blood samples were obtained after patient resting in the recumbent position for 1 h before supine samples and for 2 h in an upright position before upright samples. Samples were obtained 10 min after needle insertion in duplicate and immediately centrifuged; serum was stored at –80 C until analyzed. Only serum for quantitative measurement of human plasma aldosterone and renin was tested at room temperature within 2 h from venipuncture to avoid cryoactivation of prorenin (23).
During the same visit, in each subject we performed a TV-USG and assessed anthropometric [weight, height, BMI, waist to hip ratio (WHR)], clinical [Ferriman-Gallwey score, heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure (with a mercury sphygmomanometer in a relaxed sitting position) (5, 7), and mean blood pressure (MBP) (SBP + 2*DBP)/3], and cardiovascular (echocolor-Doppler examination of the carotid artery) measurements.
Biochemical assays
Plasma LH, FSH, 17ß-estradiol, 17
-hydroxyprogesterone (17-OHP), testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEA-S), cortisol, and prolactin were measured by specific RIAs as previously described (5, 7). The levels of SHBG were measured using immunoradiometric assay (7), and the free androgen index (FAI) was calculated as follows: testosterone (nmol/liter)/SHBG (nmol/liter) x 100. Blood insulin and glucose levels were measured by a solid-phase chemoluminescent enzyme immunoassay and the glucose oxidase method, respectively (5, 7).
The estimate of IR by homeostasis model assessment (HOMA) score [fasting serum insulin (microunits per milliliter) x fasting plasma glucose (mmol/liter)/22.5] was calculated in all subjects. Glucose and insulin concentrations were also measured 30 min after insertion of an iv catheter to detect the fasting levels (time 0) before the OGTT. Successively, each subject received a 75-g glucose load orally, and additional blood samples (10 ml each) were obtained at 30-min intervals for the following 3 h during the infusion period for assaying glucose and insulin concentrations. In the PCOS and control groups, the glucose and insulin response to OGTT was analyzed by calculating the area under curve (AUC). The AUCs for glucose (AUCGLU) and insulin (AUCINS) were determined according to the mathematical method described by Tai (24) for the metabolic curves. The lipid profile consisted of serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) levels as previously described (5, 7). CRP was measured as recently shown (5). Serum potassium and sodium concentrations (mmol/liter) were determined by standard method on flame photometer (Corning Medical and Scientific, Halstead, Essex, UK).
Cortisol assay was performed by a solid-phase competitive chemoluminescent enzyme immunoassay, using the IMMULITE 2000 Analyzer (Diagnostic Products Corporation, Los Angeles, CA). The test results were: calibration range, 1–50 µg/dl (10 to 500 ng/ml); analytical sensitivity, 0.20 µg/dl (2.0 ng/ml); linearity, 94 to 113%; and recovery, 89–109%. For cortisol in the morning, the normal range was 50–200 ng/ml. The inter- and intraassay coefficients of variation (CVs) at concentration levels of 33–310 ng/ml were 6.8 and 9.4%, respectively (25).
Aldosterone and plasma renin assay were performed with a RIA method (26). The coated tube RIA kits for in vitro diagnostic use were manufactured by Diagnostic System Laboratories, Inc. (Webster, TX) and OBI-DSL (Cherwell Innovation Centre, Upper Heyford, Oxfordshire, UK), and used a highly specific rabbit antialdosterone and antirenin polyclonal antibody. Cross-reactivity to closely related naturally occurring steroids is negligible.
Standards, controls, and sample assays were performed in duplicate for both parameters; the standard calibration curves were calculated using means replicate values of seven different levels of standard concentration analyses using a log-linear fit plot curve of radioactivity (counts per minute), %B/T (mean counts/mean totals counts x 100), or %B/B0 (mean counts/mean counts of 0 concentrations of standards x 100) for the standards (y-axis) against analyses concentrations (x-axis). The intraassay CV was lower than 4.5%. Precision was determined as described in the National Committee for Clinical Laboratory Standards Protocol EP5-T2. For aldosterone, the normal range was 3–12.5 ng/dl recumbent and 7–29.5 ng/dl upright. For renin, the normal range was 0.2–2.7 ng/ml·h supine and 1.5–5.7 ng/ml·h upright. To exclude diagnosis of primary aldosteronism, plasma aldosterone/renin ratio was calculated as aldosterone (ng/dl) to renin (ng/ml·h) (23).
Carotid artery study
Each patient underwent several longitudinal ultrasonographic scans of the carotid artery by the same experienced operator (S.D.B.), who was blinded to the clinical data, by using an echocolor-Doppler (G.E. Vingmed Ultrasound, Horten, Norway) with a high-resolution 10-MHz linear probe.
The exams were performed in the supine position, with the head hyperextended and turned away from the side being scanned. The operator scanned the right and left common carotid arteries and the carotid bifurcation bulb area from multiple planes. The intima-media thickness (IMT) of the posterior (far) wall of both common carotid arteries was measured at the end diastole from the B-mode screen as the distance between the junction of the lumen and intima and that of the media and adventitia. The mean IMT for each side was calculated as the average of 10 measurements made in the right and left carotid arteries using electronic calipers. Ambient light and temperature were controlled throughout the procedure. According to our previous experience, the intra- and interobserver CVs for the repeated measurements of IMT were 7.0 and 12.0%, respectively (7).
Statistical analysis
For continuous variables, the Kolmogorov-Smirnov statistic with a Lilliefors significance correction was used for testing normality, and data were analyzed with unpaired t test.
Bivariate correlations computing Pearson’s coefficient with their significance levels were calculated between aldosterone and other variables in PCOS and control patients.
In PCOS, multiple linear regression analysis (stepwise method) was performed with aldosterone as the dependent variable and CRP, MBP, IMT, HDL, AUCINS, insulin, glucose, and HOMA as independent variables. In assessing the suitability of the data for a linear regression model, the collinearity diagnostics were evaluated.
Data are presented as mean and SD, and P value less than 0.05 was considered statistically significant. All analyses were run using SPSS 14.0.2 (SPSS Inc., Chicago, IL).
|
Results |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
.
|
All subjects had aldosterone levels within the normal range, except for 10 patients (aldosterone slightly above the upper limit of the normal range). Nevertheless, aldosterone levels were significantly increased (P < 0.001) in PCOS compared with healthy women (10.5 ± 3.2 vs. 5.7 ± 2.5 ng/dl). Conversely, plasma renin did not significantly differ between patients and controls (Table 1
). Serum potassium levels were significantly lower (P < 0.001) in PCOS, whereas serum sodium levels were not significantly different between the two groups (Table 1). Serum fasting insulin, HOMA, AUCINS, and MBP were significantly (P < 0.05) higher in patients than in controls, whereas SBP and HR were similar in both groups (Table 2).
|
). TG levels were similar in patients and controls (Table 2). All patients and controls had an aldosterone/renin ratio less than 27 ng/dl aldosterone per ng/ml·h renin, excluding a condition of primary hyperaldosteronism (23, 27). No pathological difference was found comparing aldosterone and renin values from supine to upright position.
The correlations between aldosterone and other variables are shown in Table 3 and in Fig. 1. A significant (P < 0.001) direct correlation between plasma aldosterone and MBP, HOMA, CRP, and IMT was observed. On the other hand, potassium and HDL-C were inversely (P < 0.001) related to aldosterone levels. No correlation was found between aldosterone levels and WHR, FAI, cortisol, and renin. Finally, no correlation was found in controls.
|
|
). No predictors were found in controls.
|
|
Discussion |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
This study was carried out to investigate aldosterone levels in PCOS women and their possible relationships with important CVR factors and early atherosclerotic markers in PCOS. Our data showed that serum aldosterone levels, although within the normal range, were significantly higher in PCOS women than controls. In PCOS patients, aldosterone levels correlated to the IMT, an early atherosclerotic parameter that has already been demonstrated to be impaired in young PCOS women (7). Moreover, in this study we have shown a significant linear relation between aldosterone levels and markers of insulin sensitivity (HOMA and AUCINS) in PCOS.
Although aldosterone levels in PCOS patients were higher than controls, their concentration was within the normal range. Vasan et al. (29) recently demonstrated that increased aldosterone levels even within the physiological range predispose to the development of hypertension. Furthermore, Schmidt and Schmeider (30) showed that aldosterone may lead to CVD involving mechanisms independent of its effect on blood pressure. Indeed, not only does the vascular wall represent an epithelial-type aldosterone target tissue, but vascular cells also seem to be able to produce local aldosterone (31). Increasing experimental and clinical evidence indicates that aldosterone is an important CVR factor (8, 10). Moreover, elevated plasma aldosterone levels correlated with cardiovascular mortality (32). Aldosterone has been demonstrated to influence vascular tone and structure directly (33), even at physiological concentrations (34). This adverse role of the renin-angiotensin-aldosterone system in the vascular remodeling and in the progression of atherosclerosis has been highlighted by correlation with IMT values (35).
Here, we also show that IMT is positively and significantly correlated with aldosterone. In agreement with Romagni et al. (34), we confirmed that this correlation is present even at physiological levels of aldosterone. Moreover, we have observed increased aldosterone levels and endothelial impairment in a young population lacking the classic risk factors for CVD such as obesity, smoking habits, diabetes/glucose intolerance, dyslipidemia, or hypertension.
Inflammation is thought to play a key role in the pathophysiological mechanism of atherosclerosis and CVD (36). Several markers of inflammation, such as CRP, fibrinogen, and white blood cell count, were found to be significantly increased in PCOS (5, 37). In agreement with previous data (37, 38), here we report increased CRP levels in PCOS patients. Moreover, we found a direct correlation between CRP and aldosterone levels.
Aldosterone has a well-established proinflammatory/fibrogenic cardiovascular action (12). Several studies confirmed the hypothesis that inappropriate elevations in circulating aldosterone induce inflammation followed by necrosis and subsequent reparative fibrosis (12, 14). This proinflammatory phenotype is based on the induction of oxidative/nitrosative stress (13). Moreover, recent data show that aldosterone might directly contribute to the oxidative stress and to the onset of atherosclerotic lesions (39).
In the present study, we also found an inverse correlation between plasma aldosterone and HDL-C levels. Recently, Fallo et al. (19) evaluated the prevalence of the metabolic syndrome in primary aldosteronism, comparing it to essential hypertension; the authors (19) also observed a more frequent occurrence of hypertriglyceridemia and low HDL-C in primary hyperaldosteronism. Furthermore, low HDL-C was the most potent discriminator between the presence and the absence of the metabolic syndrome in that study (19). The metabolic syndrome and its individual components, including low HDL-C and higher TG levels, are common in PCOS, particularly among women with the highest insulin levels (28).
A putative cause of the increased aldosterone levels, even if within normal limits, observed in PCOS could be the IR. In comparison to controls, PCOS women had higher serum insulin concentrations and HOMA index, confirming previous observations (40). In our study, aldosterone levels significantly correlated with either fasting insulin concentrations or estimates of insulin sensitivity. Multiple linear regression analysis showed that only HOMA and AUCINS linearly related to aldosterone in PCOS. In support of our findings, several studies (17, 18) reported the impairment of glucose metabolism and insulin action induced by aldosterone excess. In fact, a negative effect of aldosterone excess on glucose metabolism and increased prevalence of the metabolic syndrome in primary hyperaldosteronism have been reported (19). Analysis using the hyperinsulinemic euglycemic clamp method demonstrated that glucose disposal rates, insulin sensitivity, and metabolic clearance rate of glucose were significantly lower in primary hyperaldosteronism patients when compared with healthy controls (41).
Molecular data have also confirmed that aldosterone induces a reduction of insulin binding and insulin responsiveness, and aldosterone reduced human insulin receptor mRNA levels (42). Conversely, other authors failed to observe reduced insulin sensitivity in patients with primary hyperaldosteronism (43).
All the study participants were Southern Italian white women, so further research is warranted to determine ethnic and environmental influences on serum aldosterone levels.
In conclusion, our data indicate that women with PCOS appear to have higher aldosterone levels than age- and BMI-matched controls. The significant correlation between aldosterone levels and CRP levels, HOMA index, AUCINS, and IMT in PCOS patients suggests that aldosterone may play a role in the development of proinflammatory status and vascular dysfunction, which are known to be associated with PCOS. IR may be the triggering factor for this inappropriate aldosterone increase.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
The authors have nothing to declare.
First Published Online August 29, 2006
Abbreviations: AUC, Area under the curve; BMI, body mass index; CRP, C-reactive protein; CV, coefficient of variation; CVD, cardiovascular disease; CVR, cardiovascular risk; DBP, diastolic blood pressure; FAI, free androgen index; HDL-C, high-density lipoprotein cholesterol; HOMA, homeostasis model assessment; HR, heart rate; IMT, intima-media thickness; IR, insulin resistance; LDL-C, low-density lipoprotein cholesterol; MBP, mean blood pressure; OGTT, oral glucose tolerance test; P, progesterone; PCO, polycystic ovaries; PCOS, polycystic ovary syndrome; SBP, systolic blood pressure; TC, total cholesterol; TG, triglycerides; TV-USG, transvaginal ultrasonography; WHR, waist to hip ratio.
Received February 22, 2006.
Accepted August 22, 2006.
|
References |
|---|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
This article has been cited by other articles:
 |
|
 |
|
  E. Ingelsson, M. J. Pencina, G. H. Tofler, E. J. Benjamin, K. J. Lanier, P. F. Jacques, C. S. Fox, J. B. Meigs, D. Levy, M. G. Larson, et al. Multimarker Approach to Evaluate the Incidence of the Metabolic Syndrome and Longitudinal Changes in Metabolic Risk Factors: The Framingham Offspring Study Circulation, August 28, 2007; 116(9): 984 - 992. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Armanini, D. Pellati, and C. Fiore Polycystic Ovary Syndrome: Implications of Corticotropin in the Regulation of Blood Pressure, Aldosterone, and Androgen Secretion Hypertension, August 1, 2007; 50(2): e24 - e24. [Full Text] [PDF]
|
|
|
|
|
|
M.-J. Chen and Y.-S. Yang Response to Polycystic Ovary Syndrome: Implications of Corticotropin in the Regulation of Blood Pressure, Aldosterone, and Androgen Secretion Hypertension, August 1, 2007; 50(2): e25 - e25. [Full Text] [PDF]
|
|
|
|
 |
|
 A. J. King, N. Bari Olivier, P. S. Mohankumar, J. S. Lee, V. Padmanabhan, and G. D. Fink Hypertension caused by prenatal testosterone excess in female sheep Am J Physiol Endocrinol Metab, June 1, 2007; 292(6): E1837 - E1841. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |
