1. Departments of Anatomy and Cell Biology and Translational Stem Cell Biology, Research Institute, Medical University, 9002 Varna, Bulgaria
2. Fondazione Iret, Tecnopolo R. Levi-Montalcini, Ozzano dell’Emilia, 40064 Bologna, Italy
3. Institute of Neurobiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
4. Institute of Biochemistry and Cell Biology, National Research Council, IBBC-CNR, 00185 Rome, Italy
5. Department of Translational Stem Cell Biology, Research Institute, Medical University, 9002 Varna, Bulgaria
6. Department of Urology, University St Anna Hospital, 9002 Varna, Bulgaria
7. Department of General and Clinical Pathology, Medical University, 9002 Varna, Bulgaria
8. Department of Neuroscience, Medical School, Washington University, St. Louis, MO 63110, USA