1 University of Santo Amaro, Health Sciences Post Graduation, Sao Paulo, Brazil; Federal University of Sao Paulo, Department of Medicine, Sao Paulo, Brazil.
2 Federal University of Sao Paulo, Department of Otorhinolaryngology -Head and Neck Surgery, São Paulo, Brazil.
3 University of Bonn, Department of Internal Medicine II - Cardiology, Pneumology, Angiology, Bonn, Germany.
4 University of Sao Paulo, Department of Cell and Tissue Biology, Institute of Biomedical Sciences, Sao Paulo, Brazil.
5 Federal University of Sao Paulo, Department of Medicine, Sao Paulo, Brazil; Albert Einstein Israeli Hospital, Clinical Laboratory, Sao Paulo, Brazil.
6 Federal University of Sao Paulo, Department of Medicine, Sao Paulo, Brazil.
The paper summarizes the difficulties to study the rare population of endothelial progenitor cells in clinical trials, based on the experience of our group in many publications in this area.