0027 Alternations in Contractility, Calcium Signaling and Nuclear Factor Kappa B Activation in Stem Cells Derived Cardiomyocytes Following Exposure to Obstructive Sleep Apnea Children’s Serum, and Intermittent Hypoxia

Abstract

Abstract Introduction There are cardiovascular morbid effects of OSA in adults and children. We have previously reported over-expression of Nuclear-Factor-κappa B in tonsils of children with OSA, and NF-κB activation after exposure to sera of children with OSA. In order to investigate NF-kB activation and the physiology of cardiomyocytes of human origin (CM’s), we have established an ex-vivo model where CM’s derived from human embryonic stem cells H-9.1 clone (hES) and from Induced pluripotent stem cells (iPSC) are either incubated with human sera, or exposed to intermittent hypoxia(IH) or room air (RA). Methods Serum samples were drawn following overnight polysomnography (PSG) from children with OSA (AHI>5) or control (AHI<1). Differentiated human cardiomyocytes were incubated with 5% OSA sera or control. Average cell beating/min was determined and NF-kB p50 and p65 cytoplasmic or nuclear localization were detected by immunofluorescence (operetta). CM’s were exposed to either RA or to IH (21% alternating with 1% O2, 6 cycles/h, 24 h) in a chamber (BioSpherix Instruments, Redfield, NY)Intracellular calcium transient signal (ionoptix) and mechanical contraction of CM (Musclemotion) were assessed. Results 1. Cell beating/min was reduced in cells incubated with OSA (n=10) as compared to control (n=10);(p<0.01), and following IH exposure vs RA (p<0.01),). 2. There is an over-expression of NF-κB p50, p65 subunits as a result of exposing CMs to OSA sera, and following IH exposure 3. a rapid decrease (up to 100%) was measured in calcium transient amplitude as well as contraction amplitude (p<0.05) after adding OSA sera, that was completely restored after washing. Conclusion We revealed human cardiomyocytes NF-kB activation and decreased contractility following exposure to OSA sera and to IH. The rapid decrease in calcium signaling and contractility infer the presence of factors that reversibly affects CMs contraction. This ex-vivo model enables the study of functional and molecular alterations in human CM Support Israel science Foundation (ISF) 1344/15