PLASMA ADIPONECTIN

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PLASMA ADIPONECTIN RESISTIN And INSULIN
RESISTANCE IN WOMEN WITH POLYCYSTIC OVARY
SYNDROME
BCLF, 04-07 September 2007, Antalya, Turkey
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Mine Yavuz Taslipinar1, Nedret Kilic2, Nilufer
Bayraktar3, Ismail Guler4, Ebru Ofluoglu2, Hatice
Pasaoglu2, Ozdemir Himmetoglu4

• 1Department of Biochemistry, Etlik Ihtisas
  Hospital, Ankara, Turkey
• 2Department of Biochemistry, Gazi
  University Medical Faculty, Ankara, Turkey
• 3Biochemistry Laboratory, Baskent
  University Hospital, Ankara, Turkey
• 4Department of Obstetrics and Gynecology, Gazi
  University Medicine Faculty, Ankara,
  Turkey

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POLYCYSTIC OVARY SYNDROME (PCOS)

• PCOS is the most common endocrine disorder in
  women of reproductive age
• It is defined by
• hyperandrogenism
• chronic anovulation
• and/or polycystic ovaries

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PCOS Research Diagnostic Criteria (National
Institutes of Health, April, 1990)
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Prevalence

• It affects 4-8 of women of reproductive age
• 30 of women with seconder amenorrhoea
• 75 of women with oligomenorrhoea
• 90 of women with hirsutism
• Because of this high prevalance values,
  diagnosis and treatment of PCOS is important

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Pathogenesis

• Although the syndrome was described more than
  half a century ago, the underlying cause of the
  disorder continues to be uncertain.
• Several theories have been proposed to explain
  the pathogenesis of PCOS
• Tsilchorozzidou et al. The pathophysiology of
  polycystic ovary syndrome, Clin Endocrinol, 2004
• LH theory
• Ovarian theory
• Insulin theory

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Insulin Theory

• Insulin ? decreased effect at target cell ?
  Insulin Resistance (IR)
• Insulin receptor down regulation ?
  Hyperinsulinemia
• Polycystic ovary syndrome frequently is
  associated with IR accompanied by compensatory
  hyperinsulinemia, and IR is enhanced by the
  interaction between obesity and the syndrome
• Burghen GA et al. Correlation of
  hyperandrogenism with hyperinsulinism in
  polycystic ovarian disease. J Clin
• Endocrinol Metab 199050113 6.
• Hyperinsulinemia is thought to result in
  increased androgen biosynthesis and decreased
  levels of sex-hormone-binding globulin (SHBG),
  thus playing a major role in the pathogenesis of
  hyperandrogenism

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• In addition to reproductive morbidity, insulin
  resistance and the resultant hyperinsulinism put
  patients at risk for long-term metabolic
  disorders such as diabetes, hypertension,
  dyslipidemia, and atherosclerosis
• Nestler JE. Insulin regulation of human
  ovarian androgens. Hum Reprod 199712(Suppl)53
  62

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• IR, together with dyslipidaemia, impaired glucose
  tolerance, type 2 diabetes mellitus, and elevated
  systolic blood pressure, which are more prevalent
  in obese young women with PCOS than in weight
  matched controls, suggest that women with PCOS
  are at an increased risk of cardiovascular
  disease (CVD)
• A. Dunaif, Insulin resistance and the polycystic
  ovary syndrome Mechanisms and implications for
  pathogenesis, Endocr. Rev. 18 (1997) 774800

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Adiponectin and Resistin

• The adipose tissue not only stores triglycerides
  as a source of energy but also is considered to
  be an endocrine organ that supervises energy
  metabolism through the expression of a variety of
  genes of secretory proteins as adiponectin and
  resistin

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• Adiponectin is a protein of 247 amino acids
  consisting of four domains, with a molecular
  weight of 30 kDa (adipocyte complement-related
  protein of 30 kd / Acrp 30)
• It belongs to a collagen superfamily sharing
  significant homology with collagen X and VIII,
  complement factor C1q, and tumor necrosis
  factor-alpha.
• It is product of human apM1 gene which is
  expressed exclusively in white adipose tissue
• Adiponectin is believed to have
  insulin-sensitizing, anti-atherogenic, and
  anti-inflammatory actions
• Stefan N, Stumvoll M. Adiponectinits role in
  metabolism and beyond. Horm Metab Res 200234469
  74.
• Kazumi T, Kawaguchi A, Sakai K, Hirano T,
  Yoshino G. Young men with high-normal blood
  pressure have lower serum adiponectin, smaller
  LDL size, and higher elevated heart rate than
  those with optimal blood pressure. Diabetes Care
  200225971 6.
• Weyer C, Funahashi T, Tanaka S, Hotta K,
  Matsuzawa Y, Pratley RE, et al.
  Hypoadiponectinaemia in obesity and type 2
  diabetes close association with insulin
  resistance and hyperinsulinemia. J Clin
  Endocrinol Metab 2001861930 5.

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• Circulating concentrations of adiponectin were
  decreased in subjects with obesity, type 2
  diabetes, hypertension, dyslipidemia, and
  cardiovascular disease as compared with healthy
  individuals
• Hotta K et al. Plasma concentrations of a novel,
  adipose-specific protein, adiponectin, in type 2
  diabetic patients. Arterioscler Thromb Vasc Biol
  20002015959.
• Matsubara M et al. Decreased plasma adiponectin
  concentrations in women with dyslipidemia. J Clin
  Endocrinol Metab 2002872764 9.
• Kazumi T et alYoung men with high-normal blood
  pressure have lower serum adiponectin, smaller
  LDL size, and higher elevated heart rate than
  those with optimal blood pressure. Diabetes Care
  200225971 6.
• Arita Y et al. Paradoxical decrease of an
  adipose-specific protein, adiponectin in obesity.
  Biochem Biophys Res Commun 19992577983.

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• Animal studies indicate the role of adiponectin
  as an important endogenous insulin sensitizer
• Impaired insulin sensitivity has been observed in
  adiponectin knock-out mice
• Administration of adiponectin to obese or
  diabetic mice reduces glucose excursion and
  improves insulin sensitivity

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• Women with PCOS are at high risk for developing
  type 2 diabetes
• Adiponectin levels have been reported to be lower
  in patients with type 2 diabetes
• There are limited data on the role of adiponectin
  in women with PCOS.

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• Resistin, a peptide hormone produced by
  adipocytes and macrophages, has the opposite
  effects to adiponectin on insulin sensitivity
• While the expression of adiponectin mRNA is
  reduced in obesity and in insulin resistant
  states, that of resistin is increased suggesting
  an association between the two adipokines in
  these states

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• Resistin, a novel 12.5 kDa cysteine-rich protein,
  is secreted by adipocytes, too.
• Serum resistin levels are significantly increased
  in insulin-resistant mice and genetic or
  diet-induced obese mice
• In addition, neutralization of endogenous
  resistin with antibodies significantly suppresses
  hyperglycaemia in diet-induced obese mice by
  improving insulin sensitivity
• Steppan et al., 2001

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• Considering the association of PCOS with impaired
  glucose tolerance, diabetes mellitus, and
  atherosclerosis as well as inconsistent evidence
  with regard to adipocytokins as a possible link
  between IR
• this study was performed to assess the
  adiponectin and resistin concentrations in women
  with the PCOS and age and weight matched healthy
  controls

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Material Method
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• Study centers,
• GÜ Faculty of Medicine, Medical Biochemistry
  Department
• GÜ Faculty of Medicine, Obstetrics and Gynecology
  Department
• Twenty-five patients with PCOS were participated
  in this study.

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Study Cases

• The diagnosis of PCOS was made by the presence of
  anovulation accompanied by hyperandrogenism after
  excluding other conditions that could present in
  a similar fashion
• Polycystic ovaries were defined, using
  ultrasound, by the presence of two or more of the
  following criteria enlarged ovarian volume (gt9
  ml), 10 or more follicles 210 mm in diameter,
  and increased density and volume of stroma
• Adams et al., 1986 Polson et al.,1988

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Study Cases

• Patients with DM, hyperprolactinaemia, congenital
  adrenal hyperplasia, thyroid disorders, Cushing
  disease, hypertension, hepatic or renal
  dysfunction were excluded from the study
• Twenty-five age- and weight-matched healthy
  persons with regular ovulatory cycles were formed
  to serve as the control group
• The ethics committee of Gazi University, Faculty
  of Medicine in Ankara, Turkey approved the study
  protocol. All patients signed informed consent
  forms

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Methods

• Height and weight were measured and the BMI was
  calculated in all patients and controls
• After a high carbohydrate diet for 3 days, a
  standard oral glucose tolerance test (OGTT) was
  performed

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Methods

• Glucose ? Hexokinase method
• Cholesterol ? Cholesterol esterase method
• HDL ? Fotometric method
• Trigliseride ? Fotometric method
• LDL ? Friedewald calculation
• LDL-K Total Chol- (HDL)(VLDL)-TRG/5
• BUN ? Enzimatic urease method
• Creatinin ? Picrate reaction
• Albumin ? Bromcresol green reaction
• Insulin, LH, FSH, T.Testosteron, PRL ?
  Chemilumminesans
• Estradiol, progesteron, DHEA-SO4
  immunoassay method
• Serum total estriol, S.Testosteron, ?
  Radioimmunoassay (RIA)
• androstenedion, 17a-OH progesteron,

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OGTT and HOMA-IR (oral glucose tolerance test
homeostasis model insulin resistance index)

• A 2 h oral glucose tolerance test (OGTT) with 75
  g of glucose load was performed after an
  overnight fast . Four blood samples were
  collected at 0, 30, 60 and 120 min and the plasma
  stored at -20C until assayed for glucose and
  insulin.
• The homeostasis model (HOMA) insulin resistance
  index was calculated using the formula
• Fasting Plasma Glucose X Fasting Serum Insulin /
  405

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Adiponectin and Resistin Assay

• The resistin (HUMAN) ELISA kit was purchased from
  Phoenix Pharmaceuticals Inc. (USA)
• Adiponectin (HUMAN) ELISA kit was purchased from
  AviBion Orgenium Laboratories (Finland)

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Statistics

• Results are presented as means ? SD, and data
  were analyzed by using SPSS statistical package,
  version 10.0 for Windows (SPSS Inc., Chicago, IL)
• Differences between the PCOS and control groups
  were compared by Mann-Whitney U test
• Bivariate correlation analysis (calculation of
  Spearmans coefficient) was used to assess the
  correlation between fasting plasma adiponectin
  and resistin and insulin resistance
• plt0.05 was considered significant

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Results Conclusion
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Table 1. Clinical features of groups
b pgt0.05

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Table 2. Comparisons of patients and controls
aPlt0,05
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• Our present results demonstrate that PCOS
  patients in our study have hypoadiponectinaemia
  and this finding is possibly independent of the
  degree of obesity
• On the contrary, serum resistin levels are not
  different in PCOS patients

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• In most PCOS patients, obesity probably
  represents a secondary additional pathogenetic
  condition
• Obesity may effect cardiovascular, endocrine and
  metabolic features of patients with PCOS
• We could not exclude all obese patients in our
  study although we watched to choose control group
  not to give significant difference between BMI
• We found significantly higher HOMA values in PCOS
  group compared to controls, although BMI of the
  groups were not differ from each other

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• Resistin might therefore be expected to play a
  role in PCOS, and plasma levels in these patients
  might be expected to be elevated
• However, we found that plasma resistin levels in
  PCOS did not differ from those in normal cycling
  women of a similar age and with a similar BMI as
  similar with most previous studies showing no
  significant increase in serum resistin levels in
  PCOS patients
• Panidis et al., 2004 Seow et al., 2004, 2005
  Carmina et al., 2005 Lu et al., 2005

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• But, we showed that there was a positive
  correlation between resistin and HOMA
• To date, there was no conclusive evidence of a
  correlation between serum resistin and insulin
  resistance indices

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• In our study, we did not observe a direct
  correlation between adiponectin and multiple
  measures of insulin resistance (fasting insulin,
  HOMA-IR)
• But we reported a negative correlation between
  plasma adiponectin/resistin ratio and IR indices
  assessed in women with the PCOS

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• Currently, only a few studies on resistin and
  adiponectin levels in the PCOS have been
  published
• In view of the cardiovascular risk in women with
  the PCOS, we suggest that assessment of the
  adiponectin-to-resistin ratio might be
  potentially useful in prediction of the future
  cardiovascular risk in women with the polycystic
  ovary syndrome.