Polikistik Over Sendromu Tanılı Hastalarla, Polikistik Over Sendromu Tanısı Olmayan Sağlıklı Kadınların Beyin Manyetik Rezonans Görüntülerinin Karşılaştırılması, Vücut Kitle Indeksi ve Hormon Düzeyleri ile Ilişkilerinin Belirlenmesi

Abstract

Polycystic ovary syndrome (PCOS) is a common and complex metabolic and endocrine disorder which is characterized by hyperandrogenism, chronic anovulation and polycystic ovaries on ultrasound. Obesity is another common health problem with increasing prevalence all over the world. There is a close relationship between PCOS and obesity. The amount and distribution of body fat plays an important role in prevalence of the syndrome and severity of the PCOS phenotype. In both PCOS and obesity, eating behavior and appetite regulation are thought to be altered at neuronal and hormonal levels. Deterioration of secretion and action of important appetite related hormones such as leptin, an adipocyte derived hormone, and gastrointestinal hormones such as ghrelin and glucagon like peptide-1 (GLP-1) have been reported. Neuronal imaging techniques provide valuable insights for understanding neurobiological mechanisms underlying eating behavior of human. Although there are multiple structural and functional neuroimaging studies comparing obese and lean individuals, there is lack of data comparing structural magnetic resonance imaging (MRI) properties and investigating hormonal correlations of patients with and without diagnosis of PCOS. In this study, we aimed to detect whether there are any differences in structural brain MRI properties and identify the relations between brain structure and appetite related hormones such as leptin, ghrelin and GLP-1. We included 40 women who presented to Endocrinology and Metabolism and Obstetrics and Gynecology clinics at Hacettepe University. Our study included four groups according to diagnosis of PCOS and their body mass index, as obese PCOS, lean PCOS, obese control, and lean control. Cranial MRI was performed in order to carry out brain voxel-based morphometric study and all participants underwent mixed meal test during early follicular phase (days 2-5) of menstrual cycle. In addition to basal levels of leptin, ghrelin and GLP-1, meal stimulated levels of GLP-1 at 15th, 30th, 45th, 60th, 90th, 120th and 180th minutes were obtained. In obese PCOS women compared to obese controls, we have found decreases in total brain volume (p=0.023), total gray matter volume (p=0.048) as well as decreases in left ventral diencephalon (p=0.018), left caudate nucleus (p=0.043), and left and right hippocampus (p=0.015 and p=0.042 respectively) gray matter volumes, that are important in regulation of eating behavior and maintaining energy balance. On the other hand, gray matter volume in amygdala was decreased in lean patients with PCOS than lean controls (p=0.028). The presence of PCOS did not make any difference in basal leptin, ghrelin and GLP-1 or meal stimulated levels of GLP-1. Also there were no significant relations between these hormones and brain regions where volumetric differences detected. Our study, being the first to investigate structural brain alterations in PCOS, suggests volumetric reductions in brain areas related with appetite, behavior and reward. Functional studies with larger sample size are needed to determine exact physiopathological roles of these changes and potential effects of long-term medical management on brain structure of PCOS.