PED/PEA-15 Protein, PCOS, Obesity, Insulin Sensitivity Indexes, Metformin, Oral Contraceptives
Condition: Polycystic Ovarian Syndrome; Insulin Sensitivity
MeSH terms: Polycystic Ovary Syndrome; Insulin Resistance; Hypersensitivity; Syndrome
Study type: Interventional
Phase: Phase 3

Summary: 
      Insulin-resistance plays an important role in polycystic ovary syndrome (PCOS)
      physiopathology. The phosphoprotein enriched in the diabetes (PED/PEA-15), a 15 kDa protein
      related to insulin sensitivity, is over-expressed in type 2 diabetic patients and in PCOS
      women, independently of obesity. The effectiveness of oral contraceptives pills (OCP) or
      metformin (MET) in PCOS management is still uncertain. Aim of this pilot clinical study was
      to compare the effects of OCPs or MET on the expression of PED/PEA-15 in association with
      insulin sensitivity in obese PCOS women. Outcome measures: PED/PEA-15, BMI, plasma glucose
      and insulin, 1/HOMA-IR, homeostasis model assessment of insulin resistance; QUICKI,
      quantitative insulin sensitivity check index; ISI: whole-body insulin sensitivity index.
      Study design: twenty obese PCOS women (age: 24.7±18 yr; BMI: 30±2.4 kg/m2) were randomized
      according to insulin sensitivity to receive 30 µg ethinylestradiol plus 30 mg drospirenone 21
      day/month or MET 1250 mg three times daily for 6 months. Results: At baseline, age and BMI
      were not different in the two groups; PED/PEA-15 protein expression was higher in MET than in
      OCP group (p=0.011), along with higher 1/HOMA-IR (p=0.004), and lower QUICKI and ISI (p=0.003
      and p<0.001, respectively). After treatment, independently of body weight, only in MET group
      PED/PEA-15 decreased (p=0.004), along with insulin and 1/HOMA-IR (p<0.001), and QUICKI and
      ISI increased (p<0.001). Insulin sensitivity indexes improvement correlated significantly
      with PED/PEA-15 protein expression, but not with BMI. Conclusions: PED/PEA-15 protein
      over-expression in obese PCOS women with IR reduced after a six month treatment with MET,
      while remained unchanged in the OCP group. The reduction was independent of body weight, and
      correlated with insulin sensitivity indexes. This effect further supported MET as a more
      effective therapy than OCPs for obese PCOS women with IR, also when fertility is not
      required.
    

Detailed description: 
      Subjects:

      Twenty obese PCOS women (age: 24.7±18 yr; BMI: 30±2.4 kg/m2) were consecutively admitted to
      the Endocrinology Unit of the Department of Molecular and Clinical Endocrinology and Oncology
      of the Federico II University of Naples, and were enrolled in this clinical study. The
      diagnosis of PCOS was made according to the diagnostic criteria for PCOS At study entry the
      patients were randomized in two groups of treatment, according to insulin sensitivity. OCP
      group, 10 patients (BMI 29.7± 1.5 kg/m2) received 30 µg ethinylestradiol plus 30 mg
      drospirenone 21 day/month. MET group, 10 patients (BMI 30.4± 3.1 kg/m2), received metformin
      1250 mg three times daily. The duration of follow-up was 6 months. The control group
      consisted of 10 healthy female volunteers, who were age matched.

      Methods:

      As all PCOS women were anovulatory, they underwent a progesterone challenge test (100 mg
      natural progesterone i.m.; Prontogest, Amsa, Rome, Italy), which induced uterine bleeding in
      all PCOS women. To exclude the presence of type 2 diabetes or abnormal glucose tolerance, the
      oral glucose tolerance test (OGTT) was performed and the normal glucose response to the OGTT
      was defined according to the 'Report of the Expert Committee on the diagnosis and
      classification of diabetes mellitus'.

      All anthropometric measurements were taken with subjects wearing only light clothes and
      without shoes. In each woman, weight and height were measured to calculate the BMI [weight
      (kg) divided by height squared (m2), kg/m2]. Height was measured to the nearest cm using a
      wall-mounted stadiometer. Body weight (BW) was determined to the nearest 50 g using a
      calibrated balance beam scale.

      Patients were given a standardized interview to obtain information about the duration of
      obesity, eating patterns, smok¬ing habits and physical exercise. In particular, subjects were
      also asked to make a daily record of the amount of physical activity (no exercise; ≤2-3
      h/week; ≥2-3 h/week). Preadmission food intake and dietary history were assessed by a skilled
      dietitian who used a computer-assisted interview (Winfood 1.5, Medimatica srl, Martinsicuro,
      Italy). All PCOS women received a normo-caloric diet.

      Assays:

      Blood samples were obtained between 08.00 h and 09.00 h from an antecubital vein after an
      overnight fast, with the patient in the resting position. The OGTT was performed using 75 g
      dextrose. Blood samples were obtained at 0, 30, 60, 90, 120, min for plasma glucose and
      insulin measurements. Fasting plasma glucose (FPG) levels were determined by the glucose
      oxidase method immediately after the OGTT. Fasting plasma insulin (FPI) samples were promptly
      centrifuged, plasma was separated and stored at -20°C until assay. FPI was measured by a
      solid-phase chemiluminescent enzyme immunoassay using commercially available kits (Immunolite
      Diagnostic Products Co, Los Angeles, CA). 1/HOMA-IR, QUICKI and ISI were calculated.

      PED/PEA-15 protein was measured in white-blood cells (WBC) lysates obtained from 10 to 12 ml
      of freshly collected uncoagulated whole blood, after separation with dextran 6%, using
      Western blot analysis. For Western blot analysis WBC were solubilized at 4°C in TAT buffer,
      centrifuged at 500g for 20 min, and supernatant fractions were stored at -20°C until used.
      The amount of 50 μg of lysate proteins were heated at 100°C in Laemmli buffer. Proteins were
      separated by 15% SDS-PAGE and then transferred to 0•45-mm Immobilon-P membranes (Millipore,
      Bedfort, MA). Filters were probed with PED/PEA-15 antiserum at 1:2000 dilution, revealed by
      enhanced chemiluminescence and autoradiography. The protein bands were quantified by laser
      densitometry and expressed as percentage of pixels (arbitrary units).
    

Intervention name(s): Metformin; oral contraceptive
Intervention type(s): Drug; Drug
Intervention description(s): metformin 1250 mg three times daily; 30 µg ethinylestradiol plus 30 mg drospirenone 21 day/month.
Other intervention name(s): Biguanides; estroprogestins
Intervention MeSH terms: Metformin; Biguanides; Contraceptive Agents; Contraceptives, Oral
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: PED/PEA-15 protein; PCOS; IR; metformin; OCP; Oral Contraceptive