Do thyroid hormones have any effect on the development of retinopathy of prematurity

Abstract

Correspondence (İletişim): Yeşim Coşkun, M.D. Bahcesehir Universitesi Tip Fakultesi, Cocuk Sagligi ve Hastaliklari Anabilim Dali, Istanbul, Turkey Phone (Telefon): +90 532 255 64 79 E-mail (E-posta): [email protected] Submitted Date (Başvuru Tarihi): 08.11.2019 Accepted Date (Kabul Tarihi): 18.11.2019 Copyright 2020 Haydarpaşa Numune Medical Journal OPEN ACCESS This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). 61 Coşkun et al., Do Thyroid Hormones have any Effects on the Development of Retinopathy of Prematurity? / doi: 10.14744/hnhj.2019.27122 Although there are various views on the pathogenesis of premature retinopathy, the biphasic theory proposed by Aston and Smith is the most widely acknowledged hypothesis[3, 4]. According to this theory, ROP occurs in two phases. Phase 1 is the phase in which vaso-obliteration occurs. In this phase, it is thought that significant angiogenic factors, such as the vascular endothelial factor (VEGF) and the insulin-like growth factor-1 (IGF-1), have an effect on angiogenesis. Phase 2 is the phase of neovascularization. In this phase, an increase in the secretion of angiogenic factors is observed due to hypoxia. It is believed that the main responsible period for ROP development is Phase 2, where neovascularization occurs. The thyroid hormone is necessary for normal development of the human brain during the intrauterine period and the first two years of life[5]. As the gestational week increases, the amount of serum-free thyroxine (fT4) and thyrotropin (TSH) synthesized by the fetus increases. Thyroid functions in preterm infants are affected by the immaturation of the hypothalamo-pituitary-thyroid axis, diseases and drugs used. In babies that are born mature, fT4 and TSH levels increase after birth then begin to decrease rapidly within 24 hours and continue to slow down after 48 hours. This fluctuation in thyroid functions is less common in low GW neonates[6–9]. Thyroid hormones have also been implicated to have a role in angiogenesis[10–12]. In this study, we aimed to investigate the effects of thyroid hormones on ROP development based on this information. Materials and Methods This study was retrospectively carried out with 34 GW patients who were hospitalized between January 2011 and January 2019 at Bahçeşehir University, Faculty of Medicine Göztepe Medical Park Hospital Neonatal Intensive Care Unit (NICU). The research protocol was approved by the Ethics Committee of Bahçesehir University Faculty of Medicine (No: 2019-05/10).