Rational and design of the REMOTE trial: An exploratory, pilot study to analyze REtinal MicrOcirculaTion in wEightlessness

Article type: Research Article

Authors: Binneboessel, Stephan^a | Masyuk, Maryna^a | Piayda, Kerstin^b | Bruno, Raphael Romano^a | Wernly, Bernhard^c | Jirak, Peter^c | Wolff, Georg^a | Gerdes, Norbert^a | Baldia, Philipp Heinrich^a | Kelm, Malte^a | Nienhaus, Fabian^a | Lang, Alexander^a | Winkels, Holger^d | Geerling, Gerd^e | Guthoff, Rainer^e | Kaya, Sema^e | Flossmann, Gerald^f | Riemer, Thomas^f | Baertschi, Michael^g | Jung, Christian^{a; *}

Affiliations: [a] Department of Cardiology, Pulmonology, and Vascular Medicine, Heinrich-Heine-University Duesseldorf, Medical Faculty, Duesseldorf, Germany | [b] Department of Cardiology and Vascular Medicine, Justus-Liebig-University Giessen, Medical Faculty, Giessen, Germany | [c] Department of Anaesthesiology, Paracelsus Medical University Salzburg, Perioperative Medicine and Intensive Care Medicine, Salzburg, Austria | [d] University of Cologne, Faculty of Medicine and University Hospital Cologne, Clinic III for InternalMedicine, Cologne, Germany | [e] Department of Ophthalmology, Heinrich-Heine-University Duesseldorf, MedicalFaculty, Duesseldorf, Germany | [f] iMEDOS Health GmbH, Jena, Germany | [g] Eyeness AG, Bern, Switzerland

Correspondence: [*] Corresponding author: Christian Jung, MD, PhD, Division of Cardiology, Pulmonology, and Vascular Medicine, University Duesseldorf, Moorenstraße 5, 40225 Duesseldorf, Germany. Tel.: +49 211 81 188 00; Fax: +49 211 81 195 20; E-mail: christian.jung@med.uni-duesseldorf.de.

Abstract: BACKGROUND:“Spaceflight associated neuro-ocular syndrome” (SANS) represents a challenging health condition in modern space medicine. Forty-eight percent of astronauts are diagnosed with SANS after long-term space missions. The pathophysiological mechanism seems to be multifactorial, and yet remains unknown. In this proof-of-concept study we plan to investigate retinal microcirculatory changes in weightlessness and aim to identify their role in the development of SANS. METHODS AND DESIGN:Healthy individuals will take part in a parabolic flight campaign, which recreates fractioned total weightlessness periods. The airplane is specifically equipped, and designed for the execution of parabolic flight maneuvers and scientific research in microgravity. Retinal microcirculation will be assessed with a modified fundus camera, which allows dynamic vessel analysis. We will additionally measure intra-ocular pressure and hemodynamic changes during each phase of the flight. Blood samples will be analyzed at baseline, one hour and 24 hours after exposure to weightlessness. CONCLUSIONS:This pilot study aims to investigate the feasibility of retinal microcirculation assessment during varying gravity. Results of this study may generate insights whether venous stasis in the eye, surrogated by the dilatation of retinal vessels and increase in intraocular pressure as signs of venous insufficiency, may potentially contribute to the development of SANS.

Keywords: Microgravity, parabolic flight campaign, retinal microcirculation, dynamic vessel analyzer, spaceflight associated neuro-ocular syndrome

DOI: 10.3233/CH-221691

Journal: Clinical Hemorheology and Microcirculation, vol. 84, no. 4, pp. 449-457, 2023