In this study we created a homogeneous group with patients diagnosed as severe melancholic depression in which biological factors are of major importance. In these patients, we aimed to determine serum BDNF, VEGF and leptin levels, which are all related to a neurotrophic hypothesis of depression and compare them with healthy controls. Methods Subjects The study included 40 MDD patients with melancholic features (18–65 years of age) evaluated by a semi-structured psychiatric examination. The patients were diagnosed according Inhibitors,research,lifescience,medical to the Diagnostic and Statistical Manual of Mental Disorders

[American Psychiatric Association, 1994]. Patients with an Axis I disorder other than MDD, alcohol/substance users, patients with any systemic or endocrinological disorder, pregnant women, women using oral contraceptives and patients with Inhibitors,research,lifescience,medical severe abnormalities in blood tests were excluded from the study. The patients had been drug-free for at least 3 months. Healthy controls (n = 40) were recruited from the hospital–university staff and were also assessed by a semi-structured

psychiatric interview. Informed consent was obtained from all of the participants. Inhibitors,research,lifescience,medical The study had local ethic committee approval. Complete blood count, serum electrolyte assay, liver and thyroid function tests, several hormone assays and electrocardiography were performed on all participants after an overnight fast between 8:00 and 10:00 a.m. following a general physical examination. The Hamilton Depression Rating Scale (HDRS) Inhibitors,research,lifescience,medical and Hamilton learn more anxiety Rating Scale were applied to patients to evaluate the severity of depression and anxiety. Sample preparation and analysis Blood was withdrawn from the antecubital vein in the fasting state. Blood samples were drawn into heparin-coated, ethylenediaminetetraacetic acid-containing and nonadditive tubes and

Inhibitors,research,lifescience,medical were processed in the laboratory immediately after collection. Complete blood count, serum electrolyte assay, liver function tests, thyroid function tests, cortisol, adrenocorticotropic hormone, growth hormone, sex hormones, prolactin, insulin and serum lipid profile were determined on the same day that the blood was collected. Serum samples obtained the for determination of BDNF, VEGF and leptin were kept at −80oC until the analyses. The time range for collecting the samples was about 6 months. BDNF (Phoenix Pharmaceuticals, Inc., Burlingame, CA, USA) and VEGF (Invitrogen, Camarillo, CA, USA) levels were determined by enzyme-linked immunosorbent assay kits. Leptin levels were determined by a radioimmunoassay method (Linco Research, St. Charles, MO, USA). BDNF and VEGF levels were given as pg/ml and leptin levels were given as ng/ml. Statistical analysis All statistical analyses were performed with SPSS version 13.0. Continuous variables were expressed as mean ± standard deviation. Categorical variables were expressed as frequency. The Shapiro-Wilk test was used as normality test.