1 Istituto di Anatomia Umana e Biologia Cellulare, Università Cattolica del Sacro Cuore Facoltà di Medicina e Chirurgia, Rome, Italy. Electronic address: ornella.parolini@unicatt.it.
2 Department of Obstetrics and Gynaecology, Reproductive Biology Unit, Medical University of Vienna, Austria.
3 Stem Cells and Regenerative Medicine Department, King Abdullah International Medical Research Center, College of Science and Health Professions, King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, P.O. Box 22490, Riyadh 11426, Saudi Arabia.