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Front. Public Health | doi: 10.3389/fpubh.2018.00369

Initial Assessment of Variability of Responses to Toxicants in Donor-Specific Endothelial Colony Forming Cells

  • 1Creative Scientist (United States), United States
  • 2Georgia State University, United States
  • 3Duke University, United States
  • 4ZenBio, Inc., United States

There is increased interest in using high throughput in vitro assays to characterize human population variability in response to toxicants and drugs. Utilizing primary human endothelial colony-forming cells (ECFCs) isolated from blood would be highly useful for this purpose because these cells are involved in neonatal and adult vasculogenesis. We characterized the cytotoxicity of four known toxic chemicals (NaAsO2, CdCl2, tributyltin [TBT], and menadione) and their four relatively nontoxic counterparts (Na2HAsO4, ZnCl2, SnCl2, and phytonadione, respectively) in eight ECFC clones representing four neonatal donors (3 female, 1 male donor, 2 clones per donor). ECFCs were exposed to 9 concentrations of each chemical in duplicate; cell viability was evaluated 48 hours later using the fluorescent vital dye CFDA, yielding concentration-effect curves from each experiment. Technical (day-to-day) variability of the assay, assessed from three independent experiments, was low: p-values for the differences of results were 0.74 and 0.64 for the comparison of day 2 vs. day 1 and day 3 vs. day 1, respectively. The statistical analysis used to compare the entire concentration-effect curves has revealed significant differences in levels of cytotoxicity induced by the toxic and relatively nontoxic chemical counterparts, demonstrating that donor-specific ECFCs can clearly differentiate between these two groups of chemicals. Partitioning of the total variance in the nested design assessed the contributions of between-clone and between-donor variability for different levels of cytotoxicity. Individual ECFC clones demonstrated highly reproducible responses to the chemicals. The most toxic chemical was TBT, followed by NaAsO2, CdCl2, and Menadione. Nontoxic counterparts exhibited low cytotoxicity at the higher end of concentration ranges tested. Low variability was observed between ECFC clones obtained from the same donor or different donors for CdCl2, NaAsO2, and TBT, but for menadione, the between-donor variability was much greater than the between-clone variability. The low between-clone variability indicates that an ECFC clone may represent an individual donor in cell-based assays, although this finding must be confirmed using a larger number of donors. Such confirmation would demonstrate that an in vitro ECFC-based testing platform can be used to characterize the inter-individual variability of neonatal ECFCs exposed to drugs and/or environmental toxicants.

Keywords: Animal replacement, developmental toxicity, personalized medicine, Population variability, cardiovascular, circulatory disease, vascular dysfucntion, Neonatal health, Toxicological risk assessment, in vitro assay, Cell-based assay, Endothelial (dys)function, Endothelial cell (EC), endothelial colony forming cells (ECFCs), endothelial progenitor cell

Received: 02 Oct 2018; Accepted: 03 Dec 2018.

Edited by:

Jimmy T. Efird, University of Newcastle, Australia

Reviewed by:

Hirak K. Patra, University of Cambridge, United Kingdom
Maryam Dadar, Razi Vaccine and Serum Research Institute, Iran
Volker M. Lauschke, Karolinska Institute (KI), Sweden  

Copyright: © 2018 Filonov, Tice, Luo, Grotegut, Van Kanegan, Ludlow, Il'yasova and Kinev. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Alexander Kinev, Creative Scientist (United States), Durham, United States, avkinev@gmail.com