Stromal cells from the adipose tissue-derived stromal vascular fraction and culture expanded adipose tissue-derived stromal/stem cells: a joint statement of the International Federation for Adipose Therapeutics and Science (IFATS) and the International Society for Cellular Therapy (ISCT)

Abstract

Background aims: Adipose tissue is a rich and very convenient source of cells for regenerative medicine therapeutic approaches. However, a characterization of the population of adipose-derived stromal and stem cells (ASCs) with the greatest therapeutic potential remains unclear. Under the authority of International Federation of Adipose Therapeutics and International Society for Cellular Therapy, this paper sets out to establish minimal definitions of stromal cells both as uncultured stromal vascular fraction (SVF) and as an adherent stromal/stem cells population.

Methods: Phenotypic and functional criteria for the identification of adipose-derived cells were drawn from the literature.

Results: In the SVF, cells are identified phenotypically by the following markers: CD45-CD235a-CD31-CD34+. Added value may be provided by both a viability marker and the following surface antigens: CD13, CD73, CD90 and CD105. The fibroblastoid colony-forming unit assay permits the evaluation of progenitor frequency in the SVF population. In culture, ASCs retain markers in common with other mesenchymal stromal/stem cells (MSCs), including CD90, CD73, CD105, and CD44 and remain negative for CD45 and CD31. They can be distinguished from bone-marrow-derived MSCs by their positivity for CD36 and negativity for CD106. The CFU-F assay is recommended to calculate population doublings capacity of ASCs. The adipocytic, chondroblastic and osteoblastic differentiation assays serve to complete the cell identification and potency assessment in conjunction with a quantitative evaluation of the differentiation either biochemically or by reverse transcription polymerase chain reaction.

Conclusions: The goal of this paper is to provide initial guidance for the scientific community working with adipose-derived cells and to facilitate development of international standards based on reproducible parameters.

Conflict of interest statement

Disclosure of interest: Although the purpose of this statement paper is to advance the field in an impartial manner, the authors recognize that a range of activities may be perceived as having potential for a conflict of interest. To ensure transparency, the authors acknowledge the following relationships: PB is a consultant for Celgene and collaborates with ABCell Bio. BAB has pending patents. LC collaborates with CSA21, founded CSA21 and has four international patents. MD founded Rigenerand srl and has pending patents. AJK is a consultant for BioTime, Inc., MicroAire, Inc. and LifeCell, Inc., founded The GID Group and Stemsource, Inc. (now Cytori Therapeutics) and has multiple issued and pending U.S. and foreign patents. KLM is a consultant for Tissue Genesis Inc. and American Medical Sciences, collaborates with Advanced Technologies & Regenerative Medicine and Biomet, founded S and K Discoveries and has U.S. PTO-2 issued and six applications. HR is a consultant for Baxter Innov., Bio and Bio, Evercyte and AMI and founded Trauma Care Consult. JPR is a consultant for Cohera Medical and advisor to GID group. KY collaborates with Kaneka, Inc. JMG is a consultant for Advanced Technologies & Regenerative Medicine, Anterogen, Mentor, Stemmatters and Toucan Capital, collaborates with Cognate Bioservices, Medpace/Mesoblast, Vesta Therapeutics and Zen-Bio, founded Artecel Sciences and LaCell and has multiple issued and pending U.S. and foreign patents.

Copyright © 2013 International Society for Cellular Therapy. All rights reserved.

Figures

Figure 1

Illustration of a strategy for the analysis of the cells of the SVF by flow cytometry. The cell suspension undergoes a red blood cell lysis before antibody labeling, and dead cells are excluded by DAPI labeling. (A) Analysis of live (Dapi−) and dead (Dapi+) cells. (B) Forward and side scatterplot gated on live cells to identify the cell populations; the gate excludes the cell debris. (C) The markers CD34 and CD45 distinguish two different CD34+ cell populations according to CD45. Stromal cells are CD34brightCD45−. (D) The marker combination CD34 and CD31 distinguishes stromal cells CD34brightCD31− from the endothelial cells CD34+CD31+. (E, F) An example of analysis of CD45− cell populations using CD34 and CD73 or CD90 markers. Most of the CD45− CD34bright cells are CD73+ or CD90+. The antibodies were purchased from Becton-Dickinson (San Jose, CA, USA), Beckman-Coulter (Miami, FL, USA), eBioscience (San Diego, CA, USA) and Biolegend (San Diego, CA, USA). The plots came from several laboratories of the authors.

Figure 2

A phenotypic comparison of cultured ASCs (left column) and MSCs (right column) showing similarities (CD73, CD90) and differences (CD10, CD36 and CD106) between the two types of stromal cells. The plots came from several laboratories of the authors.