Immunophenotyping of a Stromal Vascular Fraction from Microfragmented Lipoaspirate Used in Osteoarthritis Cartilage Treatment and Its Lipoaspirate Counterpart

• Main Authors: Denis Polancec, Lucija Zenic, Damir Hudetz, Igor Boric, Zeljko Jelec, Eduard Rod, Trpimir Vrdoljak, Andrea Skelin, Mihovil Plecko, Mirjana Turkalj, Boro Nogalo, Dragan Primorac
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Genes
• Subjects: lipoaspirate; microfragmented lipoaspirate; immunophenotyping; endothelial progenitors; pericytes; supra-adventitial adipose stromal cells
• Online Access: https://www.mdpi.com/2073-4425/10/6/474

Osteoarthritis (OA) is a degenerative joint disease accompanied by pain and loss of function. Adipose tissue harbors mesenchymal stem/stromal cells (MSC), or medicinal signaling cells as suggested by Caplan (Caplan, 2017), used in autologous transplantation in many clinical settings. The aim of the study was to characterize a stromal vascular fraction from microfragmented lipoaspirate (SVF-MLA) applied for cartilage treatment in OA and compare it to that of autologous lipoaspirate (SVF-LA). Samples were first stained using a DuraClone SC prototype tube for the surface detection of CD31, CD34, CD45, CD73, CD90, CD105, CD146 and LIVE/DEAD Yellow Fixable Stain for dead cell detection, followed by DRAQ7 cell nuclear dye staining, and analyzed by flow cytometry. In SVF-LA and SVF-MLA samples, the following population phenotypes were identified within the CD45^− fraction: CD31⁺CD34⁺CD73^±CD90^±CD105^±CD146^± endothelial progenitors (EP), CD31⁺CD34^−CD73^±CD90^±CD105^−CD146^± mature endothelial cells, CD31^−CD34^−CD73^±CD90⁺CD105^−CD146⁺ pericytes, CD31^−CD34⁺CD73^±CD90⁺CD105^−CD146⁺ transitional pericytes, and CD31^−CD34⁺CD73^highCD90⁺CD105^−CD146^− supra-adventitial-adipose stromal cells (SA-ASC). The immunophenotyping profile of SVF-MLA was dominated by a reduction of leukocytes and SA-ASC, and an increase in EP, evidencing a marked enrichment of this cell population in the course of adipose tissue microfragmentation. The role of EP in pericyte-primed MSC-mediated tissue healing, as well as the observed hormonal implication, is yet to be investigated.