Substance P and calcitonin gene-related neuropeptides as novel growth factors for ex vivo expansion of cord blood CD34⁺ hematopoietic stem cells

Abstract

There is little evidence on roles of growth factors other than cytokines in expansion of cord blood (CB) stem cells. We aimed to explore a novel approach for expansion, using Substance P (SP) and calcitonin gene-related peptide (CGRP) neuropeptides.

CB CD34⁺ cells were cultured in different concentrations of SP and/or CGRP in combination with a cytokine cocktail. Phenotypic and functional analysis was performed by flowcytometry and colonogenic assay.

Our results show a significant improvement of total expansion of neuropeptide treated cells. There was a selective effect of CGRP on CD34⁺ CD133⁺ cells, SP on CD34⁺ CD45^dim cells, and 10^{− 9} M SP and/or CGRP on expansion of CD34⁺ CD38⁻ cells. There was also a tendency for erythroid and granulocyte–myeloid colony formation in SP and CGRP treated cultures, respectively.

Supplementation of cytokines with other growth factors, such as neuropeptides, might enable us to overcome the difficulties of ex vivo expansion of CB cells.

Keywords::

• CGRP
• cord blood
• expansion
• stem cell
• SP

Acknowledgements

The authors would like to thank Professor P. Rameshwar for providing valuable comments on designing the neuropeptide culture condition and Professor Ormerod and Dr M. Ebrahimi for helpful advice on flowcytometry analysis. We would like to thank the staff of Cord Blood Bank of Bone Marrow Transplantation Research Center, especially Ms Raofi, for providing the CB samples. We are also grateful to Dr Mehrdad Pedram (Department of Medical Genetics, Tehran University of Medical Sciences) for his helpful comments and suggestions, as well as careful editing of the manuscript. This work was supported in part by a grant from the Iran National Science Foundation and Bone Marrow Transplantation Research Center of Tehran University of Medical Sciences.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.