Received: 27 January 2020
Accepted: 10 November 2020
First Online: 16 November 2020
Ethics approval and consent to participate
: The study was performed according to the ethical principles of the World Medical Association Declaration of Helsinki. Informed consent was obtained from all human donors. The study has been independently reviewed and approved by the Ethical Committee of the University of Bonn (reference number 029/08).
: Not applicable.
: The authors declare that they have no competing interests.