Basic Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Stem Cells. May 26, 2020; 12(5): 359-367
Published online May 26, 2020. doi: 10.4252/wjsc.v12.i5.359
How old is too old? In vivo engraftment of human peripheral blood stem cells cryopreserved for up to 18 years - implications for clinical transplantation and stability programs
John Underwood, Mahvish Rahim, Carijo West, Rebecca Britton, Elaine Skipworth, Vicki Graves, Steven Sexton, Hillary Harris, Dave Schwering, Anthony Sinn, Karen E Pollok, Kent A Robertson, W Scott Goebel, Kerry M Hege
John Underwood, Departments of Internal Medicine and Pediatrics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
Mahvish Rahim, Karen E Pollok, Kent A Robertson, W Scott Goebel, Kerry M Hege, Department of Pediatrics, Division of Pediatric Hematology/Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, United States
Carijo West, Rebecca Britton, Elaine Skipworth, Vicki Graves, Steven Sexton, Hillary Harris, Dave Schwering, Cellular Therapy Laboratory, Indiana University Health, Indianapolis, IN 46202, United States
Anthony Sinn, Karen E Pollok, Department of Pediatrics, Herman B Wells Center for Pediatric Research, In Vivo Therapeutics Core and Angio Biocore Shared Resource Facilities for the Indiana University Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN 46202, United States
Author contributions: Skipworth E, Pollok KE, Robertson KA, Goebel WS and Hege KM designed and coordinated the study; West C, Britton R, Graves V, Sexton S, Harris H, Schwering D, Sinn A, Goebel WS and Hege KM performed the experiments, acquired and analyzed data; Underwood J, Rahim M, West C, Britton R, Graves V, Sexton S, Harris H, Schwering D, Pollok KE, Robertson KA, Goebel WS and Hege KM interpreted the data; Underwood J, Rahim M, Goebel WS and Hege KM wrote the manuscript; all authors approved the final version of the manuscript.
Supported by a pilot grant from the Indiana University Center of Excellence in Molecular Hematology, NIDDK, No. P30DK090948 (to Hege KM and Goebel WS); the NIH/NCI Cancer Center, No. P30CA082709 awarded to the Indiana University Simon Comprehensive Cancer Center (to Sinn A and Pollok KE).
Institutional review board statement: The study was reviewed and approved by the Institutional Review Board of Indiana University School of Medicine.
Institutional animal care and use committee statement: All animal experiments were performed under supervision of the In Vivo Therapeutics Core using procedures approved by the Indiana University School of Medicine Institutional Animal Care and Use Committee (protocol 0000002985).
Conflict-of-interest statement: Goebel WS receives fees as a consulting medical director for Cook Regentec, LLC, and serves as medical director for Ossium Health, Inc. All other authors report no potential conflicts of interest.
Data sharing statement: No additional data are available.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: W Scott Goebel, MD, PhD, Medical Director of the Cellular Therapy Laboratory, Associate Professor of Clinical Pediatrics, Division of Pediatric Hematology/Oncology, Indiana University School of Medicine, Room 2626, 705 Riley Hospital Drive, Indianapolis, IN 46202, United States. sgoebel2@iu.edu
Received: February 28, 2020
Peer-review started: February 28, 2020
First decision: April 2, 2020
Revised: April 14, 2020
Accepted: April 28, 2020
Article in press: April 28, 2020
Published online: May 26, 2020
Processing time: 88 Days and 8.6 Hours
ARTICLE HIGHLIGHTS
Research background

Peripheral blood stem cells (PBSC) are commonly cryopreserved awaiting clinical use for hematopoietic stem cell transplant (HSCT). Long term cryopreservation is commonly defined as five years or longer, and limited data exists regarding how long PBSC can be cryopreserved and retain the ability to successfully engraft. Our study examines the engraftment potential of long-term cryopreserved PBSC units. This could allow for PBSC units to be stored for a longer time without repeated viability testing and for these units to be utilized in clinical HSCT.

Research motivation

We investigated the viability and colony-forming unit capacity in vitro, and the in vivo engraftment potential of long-term cryopreserved PBSC units. This was done to gain an understanding of the viability of long-term cryopreserved PBSC units so that these long-term cryopreserved units could be used for clinical HSCT.

Research objectives

Our intention was to investigate if long-term cryopreserved PBSC units, which are being preserved in stem cell banks for many years, can be utilized with successful in vivo engraftment. This will help with gaining insight to the potential use of long-term cryopreserved PBSC units.

Research methods

PBSC units were collected and frozen as per validated clinical protocols. The units were then thawed as per clinical standards of practice. Progenitor function was assessed with standard colony-forming assays. CD34-selected cells were transplanted into NOD/ SCID/IL-2Rγnull (NSG) mice and stem cell function was assessed.

Research results

Ten long-term cryopreserved PBSC units (mean of 17 years) demonstrated appropriate post-thaw viability of which nine had BFU-E growth and seven showed CFU-GM growth. Immunodeficient NSG mice (6-7 recipient mice/PBSC unit) were transplanted with 4 randomly selected PBSC units that were cryopreserved for up to 18 years, and all mice showed short-term and long-term engraftment and reconstitution of human myeloid and lymphoid cells. Moving forward it will be important to analyze the engraftment of long-term cryopreserved PBSC units in vivo on a larger scale.

Research conclusions

This study demonstrates the appropriate long term engraftment of clinically collected and thawed PBSC units follow cryopreservation up to 17 years in immunodeficient mice. This is one of few studies that analyzes the in vivo engraftment potential of long-term cryopreserved PBSC units. This can allow institutions to safely increase the time of safe storage for PBSC units, without further viability testing of the units. These findings are beneficial for clinical programs, stem cell banks, and regulatory and accrediting agencies interested in product stability.

Research perspectives

In summary, this study demonstrates that long-term cryopreserved PBSC can exhibit short- and long-term engraftment in immunodeficient mice with differentiation into multilineage phenotypes. Future research would be to expand studies to look at in vivo engraftment on a larger scale and ultimately to apply this to clinical transplantation in humans.