Effect of expansion of human umbilical cord blood CD34\u2009+\u2009cells on neurotrophic and angiogenic factor expression and function

Ashalyn P Watt,Suzanne L Miller,Graham Jenkin,Yen Pham,Atul Malhotra,Lakshmi Nekkanti,Mark Kirkland,Courtney Mcdonald,Guy Moeneclaey

doi:10.1007/s00441-022-03592-2

Abstract

The use of CD34 + cell-based therapies has largely been focused on haematological conditions. However, there is increasing evidence that umbilical cord blood (UCB) CD34 + -derived cells have neuroregenerative properties. Due to low cell numbers of CD34 + cells present in UCB, expansion is required to produce sufficient cells for therapeutic purposes, especially in adults or when frequent applications are required. However, it is not known whether expansion of CD34 + cells has an impact on their function and neuroregenerative capacity. We addressed this knowledge gap in this study, via expansion of UCB-derived CD34 + cells using combinations of LDL, UM171 and SR-1 to yield large numbers of cells and then tested their functionality. CD34 + cells expanded for 14 days in media containing UM171 and SR-1 resulted in over 1000-fold expansion. The expanded cells showed an up-regulation of the neurotrophic factor genes BDNF, GDNF, NTF-3 and NTF-4, as well as the angiogenic factors VEGF and ANG. In vitro functionality testing showed that these expanded cells promoted angiogenesis and, in brain glial cells, promoted cell proliferation and reduced production of reactive oxygen species (ROS) during oxidative stress. Collectively, this study showed that our 14-day expansion protocol provided a robust expansion that could produce enough cells for therapeutic purposes. These expanded cells, when tested in in vitro, maintained functionality as demonstrated through promotion of cell proliferation, attenuation of ROS production caused by oxidative stress and promotion of angiogenesis.

Highlights

Umbilical cord blood (UCB) contains a mixed population of stem and progenitor cells that includes haematopoietic stem cells (HSCs), endothelial progenitor cells (EPCs) and mesenchymal stromal cells (MSCs) (Phuc et al 2012; RouraPonds, Victoria, Australia 4 Department of Paediatrics, Monash University, Clayton, VIC, Australia 5 Department of Obstetrics and Gynaecology, MonashUniversity, Clayton, VIC, Australia et al 2015), together with immunosuppressive cells such as myeloid-derived suppressor cells (MDSC) and regulatory T cells (Tregs) (Tolar et al 2009; Gervassi et al 2014)
After 7 days of expansion, the highest fold expansion of CD34 + / CD45 + cells was observed in the group containing both UM171 and low-density lipoprotein (LDL) (45.1 ± 1.6); the percentage of cells expressing CD34/CD45 was highest in the group containing UM171 and SR-1 (68.1 ± 2.7)
After 14 days of culture, all groups had significantly higher total cell counts and CD34 + /CD45 + fold expansion compared to day 7; all groups had significantly lower CD34 + /CD45 + positivity in the cultures compared to pre-expansion and day 7

Summary

Introduction

University, Clayton, VIC, Australia et al 2015), together with immunosuppressive cells such as myeloid-derived suppressor cells (MDSC) and regulatory T cells (Tregs) (Tolar et al 2009; Gervassi et al 2014). This range of cell populations possess a diverse mix of multi-functional capacities to mediate tissue regeneration and repair, and combined with the straightforward nature of cord blood collection, makes UCB-derived cells a strong option for cell-based therapies. UCB-HSCs are more primitive and have a lower risk of rejection compared to HSCs obtained from bone marrow, even when considering allogeneic use.

Methods

Results

Conclusion