Comparison of Endothelial DifferentiationCapacities of Human and Rat Adipose-DerivedStem Cells

EXPERIMENTAL Comparison of Endothelial Differentiation Capacities of Human and Rat Adipose-Derived Stem Cells Hakan Orbay, M.D., Ph.D. Kamaljit Devi, B.S. Priscilla A. Williams, B.S. Tima Dehghani, B.S. Eduardo A. Silva, Ph.D. David E. Sahar, M.D. Sacramento and Davis, Calif. Background: The authors compared the endothelial differentiation capacities of human and rat adipose-derived stem cells to determine whether human adipose-derived stem cells can be a source of endothelial cells clinically. Methods: Human and rat adipose-derived stem cells were harvested and char- acterized with flow cytometry and trilineage differentiation. Cells from pas- sages III through V were fed with endothelial cell differentiation medium for up to 3 weeks. Cells were harvested after 1, 2, and 3 weeks, and endothelial differentiation was evaluated with quantitative reverse-transcriptase polymerase chain reaction, flow cytometry, and angiogenic sprouting assays. Results: Both human and rat adipose-derived stem cells were CD90 + , CD44 + , and CD31 − before differentiation. The cells were successfully differentiated into adipogenic, osteogenic, and chondrogenic lineages. Expression of en- dothelial cell–specific genes peaked at the second week of differentiation in both human and rat cells. The fold changes in expression of CD31, vascular endothelial growth factor receptor-1, nitric oxide synthase, and von Willebrand factor genes at week 2 were 0.4 ± 0.1, 34.7 ± 0.3, 2.03 ± 0.25, and 12.5 ± 0.3 respectively, in human adipose-derived stem cells; and 1.5 ± 1.01, 21.6 ± 1.7, 17.9 ± 0.6, and 11.2 ± 1.3, respectively, in rat cells. The percentages of CD31 + cells were 0.2, 0.64, and 1.6 in human cell populations and 0.5, 5.91, and 11.5 in rat cell populations at weeks 1, 2, and 3, respectively. Rat adipose-derived stem cell–derived endothelial cells displayed enhanced sprouting ­capability compared with the human cells. Conclusions: Human adipose-derived stem cells responded less strongly to EGM-2MV ­endothelial differentiation medium than did the rat cells. Still, the human cells have the potential to become a clinical source of endothelial cells with modifications in the differentiation conditions. (Plast. Reconstr. Surg. E merging interest in autologous stem cells and biotechnological advances have paved the way for the development of several tis- sue-engineered constructs for tissue regenera- tion. 1 However, the main roadblock preventing clinical translation of these regenerative meth- ods is the lack of a vascular system within tissue- engineered constructs. In the initial period after transplantation, thin and small constructs From the Department of Surgery, Division of Plastic Surgery, University of California, Davis Medical Center; and the De- partment of Biomedical Engineering, University of Califor- nia, Davis. Received for publication January 6, 2016; accepted July 25, The first two authors contributed equally to this work. Copyright © 2016 by the American Society of Plastic Surgeons DOI: 10.1097/PRS.0000000000002791 may successfully rely on passive diffusion for nutrition. 2,3 However, larger and more complex constructs cannot survive by means of passive dif- fusion alone. Instead, they require a sophisticated vascular network for efficient and immediate Disclosure: The authors have no financial interest to declare in relation to the content of this article. Supplemental digital content is available for this article. A direct URL citation appears in the text; simply type the URL address into any Web browser to access this content. A clickable link to the material is provided in the HTML text of this article on the Journal’s website (www.PRSJournal.com). www.PRSJournal.com Copyright © 2016 American Society of Plastic Surgeons. Unauthorized reproduction of this article is prohibited.