- Email: [email protected]
Increased circulating soluble P-selectin in polycystic ovary syndrome
Increased circulating soluble P-selectin in polycystic ovary syndrome Bulent O. Yildiz, M.D.,a Gurkan Bozdag, M.D.,b Ayla Harmanci, M.D.,a Umit Otegen, M.D.,b Kubra Boynukalin, M.D.,b Zehra Vural, M.D.,b Serafettin Kirazli, M.D.,c Ibrahim C. Haznedaroglu, M.D.,c and Hakan Yarali, M.D.b a c
Endocrinology and Metabolism Unit, Department of Internal Medicine; b Department of Obstetrics and Gynecology; and Hematology Unit, Department of Internal Medicine, Hacettepe University School of Medicine, Hacettepe, Ankara, Turkey
Objective: To determine whether the P-selectin–von Willebrand factor (vWF) pathway is altered in patients with polycystic ovary syndrome (PCOS). Design: Case-control study. Setting(s): Tertiary care academic medical center. Patient(s): Thirty-two normal glucose-tolerant patients with PCOS and 21 age- and body mass index–matched healthy women were prospectively enrolled. All the patients with PCOS had clinical and/or biochemical hyperandrogenism and chronic oligoanovulation, and 89% had polycystic ovaries on ultrasound. Intervention(s): None. Main Outcome Measure(s): Soluble P-selectin (sP-selectin), vWF, total T, sex hormone–binding globulin, total cholesterol, high-density lipoprotein cholesterol, triglycerides, fasting glucose and insulin, 2-hour glucose, and homeostatic model assessment–insulin resistance. Result(s): Soluble P-selectin levels were significantly higher in patients with PCOS compared with controls (58.7 19.0 vs. 45.3 15.0 ng/mL), whereas PCOS and control groups had similar vWF levels (46.7 24.2 vs. 39.5 22.3, respectively). There was no correlation between sP-selectin and anthropometric measurements or any of the androgen, lipid, or insulin resistance parameters. Conclusion(s): Our results suggest increments in the circulating sP-selectin concentrations associated with unaltered vWF levels in PCOS. Increased sP-selectin might potentially contribute to the future risk of cardiovascular disease in patients with PCOS. (Fertil Steril 2010;93:2311–5. 2010 by American Society for Reproductive Medicine.) Key Words: Cardiometabolic risk, thrombosis, inflammation, platelets, endothelial cell
Polycystic ovary syndrome (PCOS) is the most common endocrine disorder of reproductive-aged women, affecting approximately 5%–7% of this population (1–3). PCOS appears to be associated with increased cardiovascular disease (CVD) risk (4, 5). The increased CVD risk of the syndrome may be attributed to hyperandrogenism, obesity, dyslipidemia, and disturbances in glucose homeostasis including impaired glucose tolerance/type 2 diabetes (6–9). Thrombophilic abnormalities together with dysfibrinolysis might also contribute to the development of CVD in PCOS (10, 11). P-selectin is a cellular adhesion molecule that is stored with von Willebrand factor (vWF) in the a-granules of platelets and the Weibel-Palade bodies of endothelial cells (12). After platelet activation, P-selectin mediates adhesion of Received December 16, 2008; revised January 19, 2009; accepted January 20, 2009; published online March 3, 2009. B.O.Y. has nothing to disclose. G.B. has nothing to disclose. A.H. has nothing to disclose. U.O. has nothing to disclose. K.B. has nothing to disclose. Z.V. has nothing to disclose. S.K. has nothing to disclose. I.C.H. has nothing to disclose. H.Y. has nothing to disclose. Reprint requests: Bulent O. Yildiz, M.D., Hacettepe University, School of Medicine, Department of Internal Medicine, Endocrinology and Metabolism Unit, Hacettepe, Ankara, 06100, Turkey (FAX: 90-312-232-2518; E-mail: [email protected]).
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platelets or endothelial cells to leukocytes and promotes migration of inflammatory cells into early and advanced atherosclerotic lesions (13). Increased circulating soluble P-selectin levels in women free of CVD at baseline are associated with an increasing risk of future cardiovascular events (14). On the other hand, vWF functions in primary hemostasis by forming an adhesive bridge between platelets and vascular subendothelial structures, and increased plasma levels have been closely associated with endothelial cell dysfunction (15, 16). These observations suggest that the P-selectin-vWF pathway plays a critical role in thrombosis/atherosclerosis and may be an important target for prevention and treatment in individuals with a high risk of CVD (13). To our knowledge, there are no studies evaluating the P-selectin-vWF pathway in patients with PCOS in comparison with healthy women. In the present study, we aimed to determine whether there are any alterations in the P-selectin-vWF pathway that might contribute to the increased risk of CVD in PCOS.
MATERIALS AND METHODS Subjects We prospectively recruited 32 patients with PCOS and 21 age- and body mass index (BMI)-matched healthy controls.
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The diagnosis of PCOS was made by the presence of any two of the following three criteria: [1] clinical and/or biochemical evidence of hyperandrogenism; [2] chronic oligo-/anovulation; and/or [3] polycystic ovaries on ultrasound (PCO) (17). Hyperandrogenism and chronic oligoanovulation were defined as described elsewhere (11, 18). PCO was defined as the presence of 12 or more follicles in each ovary, each measuring 2–9 mm in diameter and/or increased ovarian volume (>10 mL) (17, 19). Cushing’s syndrome, nonclassical congenital adrenal hyperplasia, hyperprolactinemia, thyroid dysfunction, and androgen-secreting tumors were excluded as suggested (17). Subjects were not taking any medication for at least 3 months before the study. The control group consisted of healthy women who had regular menstrual cycles without clinical or biochemical hyperandrogenism or PCO. They did not have a history of any drug intake for at least 3 months. None of the participants in the study had impaired fasting glucose, impaired glucose tolerance, or type 2 diabetes. Exclusion criteria included smoking and alcohol in both groups. Study Protocol The study protocol was approved by Institutional Review Board of Hacettepe University Medical School, and informed consent was obtained from all participants. Anthropometric measurements including body mass index (BMI), waist circumference, and waist-to-hip ratio (WHR; waist, midway between the lower rib margin and the iliac crest; hip, widest circumference over the great trochanters) were determined. Subjects underwent a standard 2-hour 75 oral glucose tolerance test between 8 and 10 hours after an overnight fast during which fasting and 120 minute glucose levels obtained. All sampling procedures were performed in the early follicular phase (day 2–5). Blood samples were drawn from large antecubital veins of the forearm and centri fuged, within 30 minutes of collection, at 4 C for 20 minutes at 3000 rpm. Fasting serum and plasma samples obtained were transferred into polypropylene tubes and stored, for up to 3 months, at 80 C, until assayed for sP-selectin, vWF antigen, total T (tT), sex hormone–binding globulin (SHBG), fasting insulin, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG). Assays Plasma sP-selectin levels were measured by enzyme-linked immunosorbent assay using a commercially available assay (R&D Systems Europe Ltd., Oxon, UK). The intra- and inter-assay coefficients of variation (CVs) for this assay were 5.1% and 9.8%, respectively. The vWF antigen levels were analyzed using the immunoturbidimetric assay (STA-Liatest vWF, Diagnostica Stago, Asnieres, France). The intra- and interassay CVs for this assay were 5.4% and 7.9%, respectively. Plasma glucose was measured by the glucose oxidase technique (Roche Molecular Biochemicals, Mannheim, Germany). Insulin was measured by radioimmunoassay 2312
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(Diagnostic Systems Laboratories, Inc., Webster, TX). The intra- and interassay CVs were 4.5% and 8.9%, respectively. The tT levels were measured by chemiluminescent enzyme immunoassay (Immulite 2000; Diagnostic Products Corporation, Los Angeles, CA), with intra- and interassay CVs of 6% and 7%, respectively. SHBG was measured by IRMA (Diagnostic Systems Laboratories), with intra- and interassay CVs of 3.7% and 9.4%, respectively. Plasma total cholesterol, HDL-C, and TG levels were determined by the enzymatic colorimetric method (Roche Molecular Biochemicals). The average intraand interassay CVs were 1.4% and 2.2%, respectively. The free androgen index (FAI) was calculated from tT and SHBG levels (FAI ¼ tT 100/SHBG). Homeostasis model assessment–insulin resistance (HOMA-IR) (35) was applied using the following formula: (HOMA-IR) ¼ fasting insulin (mU/mL) fasting glucose (mmol)/22.5. Data Analysis All parameters are given as mean SD. Between-group comparisons were performed using the independent-samples t-test. Spearman’s test was used for correlation analyses. P<.05 was considered statistically significant. Data analysis was performed using the Statistical Package for Social Sciences, version 13.0 (SPSS Inc., Chicago). RESULTS The clinical, hormonal, and metabolic features of the women with PCOS and controls are shown in Table 1. All the patients had clinical and/or biochemical hyperandrogenism and chronic oligoanovulation, and 89% had PCO on ultrasound. The age, BMI, and WHR were similar among the patients with PCOS and controls, while PCOS patients had a higher waist circumference (P<.05; Table 1). As expected, tT and FAI levels were significantly higher in patients with PCOS compared with those in controls (P<.01 for both; Table 1). The groups did not differ with regard to total cholesterol, HDL-C, and TG levels. Although the two groups had similar fasting and 2-hour glucose levels, fasting insulin levels and HOMA-IR values were higher in patients with PCOS compared with controls (P<.01 for both; Table 1). Of interest, the platelet counts (103/mL) were also found to be higher in patients with PCOS. The sP-selectin levels were higher in patients with PCOS compared with those in controls (58.7 19.0 vs. 45.3 15.0 ng/mL; P<.01); however, both groups had similar vWF levels (46.7 24.2 vs. 39.5 22.3, respectively; NS). The sP-selectin and the vWF levels in the PCOS group did not show a correlation with any of the anthropometric variables, platelet counts, androgen, insulin resistance, or lipid parameters (data not shown). DISCUSSION Women with PCOS generally have established risk factors for CVD including insulin resistance, impaired glucose Vol. 93, No. 7, May 1, 2010
TABLE 1 The clinical, hormonal and metabolic features of the women with PCOS and controls. Variable Age, y Body mass index, kg/m2 Waist, cm Waist-to-hip ratio Total T, nmol/L Free androgen index Total cholesterol, mmol/L HDL-C, mmol/L TG, mmol/L Fasting glucose, mmol/L Fasting insulin, pmol/L 2-h glucose, mmol/L HOMA-IR Platelets (103/mL) sP-selectin, ng/mL vWF
PCOS (n[38)
Controls (n[23)
P value
24.8 3.9 24.2 4.2
27.3 5.1 23.0 2.7
NS NS
80.1 15.1 0.78 0.09 3.4 1.8 6.4 3.7 4.2 0.6 1.6 0.3 0.9 0.4 4.6 0.5 112.5 56.3 4.5 0.9 3.3 1.6 281 58 58.7 19.0 46.7 24.2
73.5 10.8 0.76 0.05 0.9 0.7 2.0 1.1 4.4 0.8 1.7 0.3 0.8 0.4 4.4 0.4 72.9 31.3 4.6 0.7 2.1 0.9 226 44 45.3 15.0 39.5 22.3
<0.05 NS <0.01 <0.01 NS NS NS NS <0.01 NS <0.01 <0.05 <0.01 NS
Note: All values are expressed as mean SD; NS ¼ not significant. Yildiz. P-selectin in PCOS. Fertil Steril 2010.
tolerance, type 2 diabetes, and obesity. Available data suggest that low-grade chronic inflammation, endothelial dysfunction (5, 10, 20–23), and thrombophilic abnormalities associated with dysfibrinolysis might play a role in increased CVD risk with the syndrome (10, 11). We hypothesized that the sPselectin-vWF pathway is altered in PCOS and that this alteration might contribute to the increased CVD risk in apparently healthy young women with PCOS. We report here an increase in sP-selectin levels and unaltered vWF in women with PCOS. P-selectin is found on the surface of activated platelets and endothelial cells and as a soluble form in the circulation. It is an adhesion molecule expressed on activated endothelial cells and platelets that mediates initial leukocyte ‘‘rolling’’ to the subendothelial region, which progresses to the formation of an atherogenic plaque (24). Therefore, P-selectin plays a major role in the cascade of inflammation, thrombosis, and coagulation at the site of vascular injury. Levels of sP-selectin are reported to be increased in patients with hypertension (25), dyslipidemia (26), and documented atherosclerosis (27). More importantly, circulating sP-selectin levels have been reported to be elevated among apparently healthy women at risk for future cardiovascular events, suggesting that this molecule might serve as a potential therapeutic target for the prevention of CVD (14). There is a lack of data on the sP-selectin levels in patients with PCOS compared with healthy women. The only available study in this context reported a reduction of sP-selectin levels by administration of acarbose for 6 months in obese Fertility and Sterility
patients with PCOS (28). Recently, it was reported that the soluble endothelial leukocyte adhesion molecule-1 (sE-selectin), which reflects low-grade inflammation of the endothelium (29), is higher in patients with PCOS compared with healthy women (21). In the present study, we documented significantly higher sP-selectin levels in patients with PCOS compared with healthy women. Since serum E2 levels might modulate sP-selectin levels during different phases of the menstrual cycle (30), the sP-selectin levels in our study were measured during the early follicular phase, at which serum E2 levels in PCOS are similar to those found in healthy women (31). The majority of the circulating sP-selectin derives from platelets (32), and sP-selectin appears to be a reliable marker of platelet hyperactivity (33). However, our method of measurement in this study does not distinguish between the contribution of platelets and endothelial cells to the sP-selectin levels. Even though we also found increased platelet counts that might suggest platelet activation in PCOS patients, we did not directly measure platelet expression of P-selectin, and sP-selectin levels did not correlate with platelet counts. It is noteworthy that we failed to show any correlation between sP-selectin levels and the adiposity, androgen, lipid, insulin, and glucose measures in PCOS group. These data suggest that increased sP-selectin levels might be an independent contributor to the increased risk of future CVD in PCOS irrespective of associated other well-established risk factors such as insulin resistance, obesity, dyslipidemia, and hyperandrogenism. Alternatively, we might have failed to detect 2313
an association between sP-selectin and insulin resistance owing to the insensitivity of the surrogates we have implied in our study (34, 35), although we should note that P-selectin levels do not correlate, for example, with total glucose disposal during euglycemic hyperinsulinemic clamp (36). Methodology is a less likely explanation for the lack of association between sP-selectin and obesity as the surrogates we have used in this study are good predictors of adiposity (37, 38). Lastly, our results do not preclude any potential associations between sP-selectin, and other emerging cardiovascular risk factors in PCOS that were not measured in our study. The vWF is stored with P-selectin in thrombocytes and endothelial cells and facilitates platelet adhesion into the subendothelium. An increased plasma level of vWF is an established marker of endothelial injury and may indicate endothelial dysfunction (15, 16). Increased levels are documented in patients with hypertension (25), dyslipidemia (26), and diabetes (39). Limited available data on the vWF levels in patients with PCOS suggest that the levels in the syndrome are similar to those observed in healthy women (40, 41). In accordance with these findings, we also failed to show any alteration in vWF levels among patients with PCOS compared with ageand BMI-matched healthy controls. We conclude that sP-selectin levels are increased in young, normal glucose-tolerant women with PCOS and that this increase is not associated with a change in vWF levels or other traditional CVD risk factors of the syndrome. Whether sP-selectin might serve as a potential biomarker for the prediction of future cardiovascular events in PCOS remains to be determined in larger studies.
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30. Jilma B, Hildebrandt J, Kapiotis S, Wagner OF, Kitzweger E, Mullner C, et al. Effects of estradiol on circulating P-selectin. J Clin Endocrinol Metab 1996;81:2350–5. 31. DeVane GW, Czekala NM, Judd HL, Yen SS. Circulating gonadotropins, estrogens, and androgens in polycystic ovarian disease. Am J Obstet Gynecol 1975;121:496–500. 32. Blann AD, Nadar SK, Lip GY. The adhesion molecule P-selectin and cardiovascular disease. Eur Heart J 2003;24:2166–79. 33. Cleanthis M, Smout J, Bhattacharya V, Ashour H, Dyker A, Ford GA, et al. Soluble but not platelet P-selectin correlates with spontaneous platelet aggregation: a pilot study. Clin Appl Thromb Hemost 2008;14:227–33. 34. Diamanti-Kandarakis E, Kouli C, Alexandraki K, Spina G. Failure of mathematical indices to accurately assess insulin resistance in lean, overweight, or obese women with polycystic ovary syndrome. J Clin Endocrinol Metab 2004;89:1273–6. 35. Yildiz BO, Gedik O. Assessment of glucose intolerance and insulin sensitivity in polycystic ovary syndrome. Reprod Biomed Online 2004;8:649–56. 36. Targher G, Bonadonna RC, Alberiche M, Zenere MB, Muggeo M, Bonora E. Relation between soluble adhesion molecules and insulin sen-
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Endocrinology and Metabolism Unit, Department of Internal Medicine; b Department of Obstetrics and Gynecology; and Hematology Unit, Department of Internal Medicine, Hacettepe University School of Medicine, Hacettepe, Ankara, Turkey
Objective: To determine whether the P-selectin–von Willebrand factor (vWF) pathway is altered in patients with polycystic ovary syndrome (PCOS). Design: Case-control study. Setting(s): Tertiary care academic medical center. Patient(s): Thirty-two normal glucose-tolerant patients with PCOS and 21 age- and body mass index–matched healthy women were prospectively enrolled. All the patients with PCOS had clinical and/or biochemical hyperandrogenism and chronic oligoanovulation, and 89% had polycystic ovaries on ultrasound. Intervention(s): None. Main Outcome Measure(s): Soluble P-selectin (sP-selectin), vWF, total T, sex hormone–binding globulin, total cholesterol, high-density lipoprotein cholesterol, triglycerides, fasting glucose and insulin, 2-hour glucose, and homeostatic model assessment–insulin resistance. Result(s): Soluble P-selectin levels were significantly higher in patients with PCOS compared with controls (58.7 19.0 vs. 45.3 15.0 ng/mL), whereas PCOS and control groups had similar vWF levels (46.7 24.2 vs. 39.5 22.3, respectively). There was no correlation between sP-selectin and anthropometric measurements or any of the androgen, lipid, or insulin resistance parameters. Conclusion(s): Our results suggest increments in the circulating sP-selectin concentrations associated with unaltered vWF levels in PCOS. Increased sP-selectin might potentially contribute to the future risk of cardiovascular disease in patients with PCOS. (Fertil Steril 2010;93:2311–5. 2010 by American Society for Reproductive Medicine.) Key Words: Cardiometabolic risk, thrombosis, inflammation, platelets, endothelial cell
Polycystic ovary syndrome (PCOS) is the most common endocrine disorder of reproductive-aged women, affecting approximately 5%–7% of this population (1–3). PCOS appears to be associated with increased cardiovascular disease (CVD) risk (4, 5). The increased CVD risk of the syndrome may be attributed to hyperandrogenism, obesity, dyslipidemia, and disturbances in glucose homeostasis including impaired glucose tolerance/type 2 diabetes (6–9). Thrombophilic abnormalities together with dysfibrinolysis might also contribute to the development of CVD in PCOS (10, 11). P-selectin is a cellular adhesion molecule that is stored with von Willebrand factor (vWF) in the a-granules of platelets and the Weibel-Palade bodies of endothelial cells (12). After platelet activation, P-selectin mediates adhesion of Received December 16, 2008; revised January 19, 2009; accepted January 20, 2009; published online March 3, 2009. B.O.Y. has nothing to disclose. G.B. has nothing to disclose. A.H. has nothing to disclose. U.O. has nothing to disclose. K.B. has nothing to disclose. Z.V. has nothing to disclose. S.K. has nothing to disclose. I.C.H. has nothing to disclose. H.Y. has nothing to disclose. Reprint requests: Bulent O. Yildiz, M.D., Hacettepe University, School of Medicine, Department of Internal Medicine, Endocrinology and Metabolism Unit, Hacettepe, Ankara, 06100, Turkey (FAX: 90-312-232-2518; E-mail: [email protected]).
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platelets or endothelial cells to leukocytes and promotes migration of inflammatory cells into early and advanced atherosclerotic lesions (13). Increased circulating soluble P-selectin levels in women free of CVD at baseline are associated with an increasing risk of future cardiovascular events (14). On the other hand, vWF functions in primary hemostasis by forming an adhesive bridge between platelets and vascular subendothelial structures, and increased plasma levels have been closely associated with endothelial cell dysfunction (15, 16). These observations suggest that the P-selectin-vWF pathway plays a critical role in thrombosis/atherosclerosis and may be an important target for prevention and treatment in individuals with a high risk of CVD (13). To our knowledge, there are no studies evaluating the P-selectin-vWF pathway in patients with PCOS in comparison with healthy women. In the present study, we aimed to determine whether there are any alterations in the P-selectin-vWF pathway that might contribute to the increased risk of CVD in PCOS.
MATERIALS AND METHODS Subjects We prospectively recruited 32 patients with PCOS and 21 age- and body mass index (BMI)-matched healthy controls.
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The diagnosis of PCOS was made by the presence of any two of the following three criteria: [1] clinical and/or biochemical evidence of hyperandrogenism; [2] chronic oligo-/anovulation; and/or [3] polycystic ovaries on ultrasound (PCO) (17). Hyperandrogenism and chronic oligoanovulation were defined as described elsewhere (11, 18). PCO was defined as the presence of 12 or more follicles in each ovary, each measuring 2–9 mm in diameter and/or increased ovarian volume (>10 mL) (17, 19). Cushing’s syndrome, nonclassical congenital adrenal hyperplasia, hyperprolactinemia, thyroid dysfunction, and androgen-secreting tumors were excluded as suggested (17). Subjects were not taking any medication for at least 3 months before the study. The control group consisted of healthy women who had regular menstrual cycles without clinical or biochemical hyperandrogenism or PCO. They did not have a history of any drug intake for at least 3 months. None of the participants in the study had impaired fasting glucose, impaired glucose tolerance, or type 2 diabetes. Exclusion criteria included smoking and alcohol in both groups. Study Protocol The study protocol was approved by Institutional Review Board of Hacettepe University Medical School, and informed consent was obtained from all participants. Anthropometric measurements including body mass index (BMI), waist circumference, and waist-to-hip ratio (WHR; waist, midway between the lower rib margin and the iliac crest; hip, widest circumference over the great trochanters) were determined. Subjects underwent a standard 2-hour 75 oral glucose tolerance test between 8 and 10 hours after an overnight fast during which fasting and 120 minute glucose levels obtained. All sampling procedures were performed in the early follicular phase (day 2–5). Blood samples were drawn from large antecubital veins of the forearm and centri fuged, within 30 minutes of collection, at 4 C for 20 minutes at 3000 rpm. Fasting serum and plasma samples obtained were transferred into polypropylene tubes and stored, for up to 3 months, at 80 C, until assayed for sP-selectin, vWF antigen, total T (tT), sex hormone–binding globulin (SHBG), fasting insulin, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG). Assays Plasma sP-selectin levels were measured by enzyme-linked immunosorbent assay using a commercially available assay (R&D Systems Europe Ltd., Oxon, UK). The intra- and inter-assay coefficients of variation (CVs) for this assay were 5.1% and 9.8%, respectively. The vWF antigen levels were analyzed using the immunoturbidimetric assay (STA-Liatest vWF, Diagnostica Stago, Asnieres, France). The intra- and interassay CVs for this assay were 5.4% and 7.9%, respectively. Plasma glucose was measured by the glucose oxidase technique (Roche Molecular Biochemicals, Mannheim, Germany). Insulin was measured by radioimmunoassay 2312
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(Diagnostic Systems Laboratories, Inc., Webster, TX). The intra- and interassay CVs were 4.5% and 8.9%, respectively. The tT levels were measured by chemiluminescent enzyme immunoassay (Immulite 2000; Diagnostic Products Corporation, Los Angeles, CA), with intra- and interassay CVs of 6% and 7%, respectively. SHBG was measured by IRMA (Diagnostic Systems Laboratories), with intra- and interassay CVs of 3.7% and 9.4%, respectively. Plasma total cholesterol, HDL-C, and TG levels were determined by the enzymatic colorimetric method (Roche Molecular Biochemicals). The average intraand interassay CVs were 1.4% and 2.2%, respectively. The free androgen index (FAI) was calculated from tT and SHBG levels (FAI ¼ tT 100/SHBG). Homeostasis model assessment–insulin resistance (HOMA-IR) (35) was applied using the following formula: (HOMA-IR) ¼ fasting insulin (mU/mL) fasting glucose (mmol)/22.5. Data Analysis All parameters are given as mean SD. Between-group comparisons were performed using the independent-samples t-test. Spearman’s test was used for correlation analyses. P<.05 was considered statistically significant. Data analysis was performed using the Statistical Package for Social Sciences, version 13.0 (SPSS Inc., Chicago). RESULTS The clinical, hormonal, and metabolic features of the women with PCOS and controls are shown in Table 1. All the patients had clinical and/or biochemical hyperandrogenism and chronic oligoanovulation, and 89% had PCO on ultrasound. The age, BMI, and WHR were similar among the patients with PCOS and controls, while PCOS patients had a higher waist circumference (P<.05; Table 1). As expected, tT and FAI levels were significantly higher in patients with PCOS compared with those in controls (P<.01 for both; Table 1). The groups did not differ with regard to total cholesterol, HDL-C, and TG levels. Although the two groups had similar fasting and 2-hour glucose levels, fasting insulin levels and HOMA-IR values were higher in patients with PCOS compared with controls (P<.01 for both; Table 1). Of interest, the platelet counts (103/mL) were also found to be higher in patients with PCOS. The sP-selectin levels were higher in patients with PCOS compared with those in controls (58.7 19.0 vs. 45.3 15.0 ng/mL; P<.01); however, both groups had similar vWF levels (46.7 24.2 vs. 39.5 22.3, respectively; NS). The sP-selectin and the vWF levels in the PCOS group did not show a correlation with any of the anthropometric variables, platelet counts, androgen, insulin resistance, or lipid parameters (data not shown). DISCUSSION Women with PCOS generally have established risk factors for CVD including insulin resistance, impaired glucose Vol. 93, No. 7, May 1, 2010
TABLE 1 The clinical, hormonal and metabolic features of the women with PCOS and controls. Variable Age, y Body mass index, kg/m2 Waist, cm Waist-to-hip ratio Total T, nmol/L Free androgen index Total cholesterol, mmol/L HDL-C, mmol/L TG, mmol/L Fasting glucose, mmol/L Fasting insulin, pmol/L 2-h glucose, mmol/L HOMA-IR Platelets (103/mL) sP-selectin, ng/mL vWF
PCOS (n[38)
Controls (n[23)
P value
24.8 3.9 24.2 4.2
27.3 5.1 23.0 2.7
NS NS
80.1 15.1 0.78 0.09 3.4 1.8 6.4 3.7 4.2 0.6 1.6 0.3 0.9 0.4 4.6 0.5 112.5 56.3 4.5 0.9 3.3 1.6 281 58 58.7 19.0 46.7 24.2
73.5 10.8 0.76 0.05 0.9 0.7 2.0 1.1 4.4 0.8 1.7 0.3 0.8 0.4 4.4 0.4 72.9 31.3 4.6 0.7 2.1 0.9 226 44 45.3 15.0 39.5 22.3
<0.05 NS <0.01 <0.01 NS NS NS NS <0.01 NS <0.01 <0.05 <0.01 NS
Note: All values are expressed as mean SD; NS ¼ not significant. Yildiz. P-selectin in PCOS. Fertil Steril 2010.
tolerance, type 2 diabetes, and obesity. Available data suggest that low-grade chronic inflammation, endothelial dysfunction (5, 10, 20–23), and thrombophilic abnormalities associated with dysfibrinolysis might play a role in increased CVD risk with the syndrome (10, 11). We hypothesized that the sPselectin-vWF pathway is altered in PCOS and that this alteration might contribute to the increased CVD risk in apparently healthy young women with PCOS. We report here an increase in sP-selectin levels and unaltered vWF in women with PCOS. P-selectin is found on the surface of activated platelets and endothelial cells and as a soluble form in the circulation. It is an adhesion molecule expressed on activated endothelial cells and platelets that mediates initial leukocyte ‘‘rolling’’ to the subendothelial region, which progresses to the formation of an atherogenic plaque (24). Therefore, P-selectin plays a major role in the cascade of inflammation, thrombosis, and coagulation at the site of vascular injury. Levels of sP-selectin are reported to be increased in patients with hypertension (25), dyslipidemia (26), and documented atherosclerosis (27). More importantly, circulating sP-selectin levels have been reported to be elevated among apparently healthy women at risk for future cardiovascular events, suggesting that this molecule might serve as a potential therapeutic target for the prevention of CVD (14). There is a lack of data on the sP-selectin levels in patients with PCOS compared with healthy women. The only available study in this context reported a reduction of sP-selectin levels by administration of acarbose for 6 months in obese Fertility and Sterility
patients with PCOS (28). Recently, it was reported that the soluble endothelial leukocyte adhesion molecule-1 (sE-selectin), which reflects low-grade inflammation of the endothelium (29), is higher in patients with PCOS compared with healthy women (21). In the present study, we documented significantly higher sP-selectin levels in patients with PCOS compared with healthy women. Since serum E2 levels might modulate sP-selectin levels during different phases of the menstrual cycle (30), the sP-selectin levels in our study were measured during the early follicular phase, at which serum E2 levels in PCOS are similar to those found in healthy women (31). The majority of the circulating sP-selectin derives from platelets (32), and sP-selectin appears to be a reliable marker of platelet hyperactivity (33). However, our method of measurement in this study does not distinguish between the contribution of platelets and endothelial cells to the sP-selectin levels. Even though we also found increased platelet counts that might suggest platelet activation in PCOS patients, we did not directly measure platelet expression of P-selectin, and sP-selectin levels did not correlate with platelet counts. It is noteworthy that we failed to show any correlation between sP-selectin levels and the adiposity, androgen, lipid, insulin, and glucose measures in PCOS group. These data suggest that increased sP-selectin levels might be an independent contributor to the increased risk of future CVD in PCOS irrespective of associated other well-established risk factors such as insulin resistance, obesity, dyslipidemia, and hyperandrogenism. Alternatively, we might have failed to detect 2313
an association between sP-selectin and insulin resistance owing to the insensitivity of the surrogates we have implied in our study (34, 35), although we should note that P-selectin levels do not correlate, for example, with total glucose disposal during euglycemic hyperinsulinemic clamp (36). Methodology is a less likely explanation for the lack of association between sP-selectin and obesity as the surrogates we have used in this study are good predictors of adiposity (37, 38). Lastly, our results do not preclude any potential associations between sP-selectin, and other emerging cardiovascular risk factors in PCOS that were not measured in our study. The vWF is stored with P-selectin in thrombocytes and endothelial cells and facilitates platelet adhesion into the subendothelium. An increased plasma level of vWF is an established marker of endothelial injury and may indicate endothelial dysfunction (15, 16). Increased levels are documented in patients with hypertension (25), dyslipidemia (26), and diabetes (39). Limited available data on the vWF levels in patients with PCOS suggest that the levels in the syndrome are similar to those observed in healthy women (40, 41). In accordance with these findings, we also failed to show any alteration in vWF levels among patients with PCOS compared with ageand BMI-matched healthy controls. We conclude that sP-selectin levels are increased in young, normal glucose-tolerant women with PCOS and that this increase is not associated with a change in vWF levels or other traditional CVD risk factors of the syndrome. Whether sP-selectin might serve as a potential biomarker for the prediction of future cardiovascular events in PCOS remains to be determined in larger studies.
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