Successful isolation and ex vivo expansion of human mesenchymal stem/stromal cells obtained from different synovial tissue‐derived (biopsy) samples

Abstract

Mesenchymal stromal cells (MSC) isolated from synovial tissues constitute a novel source of stem-like cells with promising applications in cartilage regeneration and potentially in other regenerative medicine and tissue-engineering settings. Detailed characterization of these cells is lacking, thus compromising their full potential. Here we present the detailed characterization of the ex vivo expansion of synovium-derived stromal cells collected by three different biopsy methods: synovium-direct biopsy, arthroscopic trocar shaver blade filtrate, and cells isolated from synovial fluid (SF) samples. Isolation success rates were >75% for all sources. MSC obtained from the different samples displayed the characteristic immunophenotype of adult MSC, expressing CD73, CD90, and CD105. Arthroscopic shaver blade-derived cells showed the higher proliferation capacity measured by the fold increase (FI) in total cell number over several passages and considering their cumulative population doublings (CPD; 15 ± 0.85 vs. 13 ± 0.73 for synovium vs. 11 ± 0.97 for SF). Also, these cells were able to sustain an increased proliferation under hypoxic (2% O ) conditions (FI 55 ± 4 vs. 37 ± 7) after 17 days in culture. Expanded cells were able to differentiate successfully along the osteogenic, adipogenic, and chondrogenic lineages in vitro. Overall, these results demonstrate that synovial tissues represent a promising source for the isolation of human MSC, while depicting the variability associated to the biopsy method used, which impact cell behavior in vitro.

Scalable Manufacturing of Human Mesenchymal Stromal Cells in the Vertical‐Wheel Bioreactor System: An Experimental and Economic Approach

“…Mesenchymal stromal cells (MSC) have been receiving great interest in clinical settings due to their self‐renewal capacity, differentiation potential, and immunomodulatory and regenerative properties . By using the minimal criteria proposed by the International Society for Cellular Therapy (ISCT), MSC have been isolated from different human tissues, including bone marrow (BM), adipose tissue (AT), synovial membrane, periosteum, umbilical cord matrix (UCM), placenta, and amniotic fluid . Numerous studies have shown that MSC isolated from different sources present different biological features, such as distinct expression of cell surface markers, proliferative capacity, differentiation ability, and immunomodulatory and regenerative features …”

Nomenclature clarification: synovial fibroblasts and synovial mesenchymal stem cells

“…One of the other aspects of the definition of MSCs offered by the ISCT is the differentiation potential of the cells into osteocytes, adipocytes, and chondrocytes in vitro. Synovium-derived MSCs have been shown to differentiate into these three cells [6, 49, 50]. Although Alt et al [46] found that fibroblasts exhibited no differentiation potential, other studies have shown that fibroblasts do possess the potential to differentiate into osteocytes, adipocytes, and chondrocytes [45, 47, 51].…”

Infrapatellar Fat Pad/Synovium Complex in Early-Stage Knee Osteoarthritis: Potential New Target and Source of Therapeutic Mesenchymal Stem/Stromal Cells

“…Located within the synovial intima and sub-intima lie distinct MSC populations similar to IFP-MSC, with an origin still debated ( Li et al, 2019 ; Sivasubramaniyan et al, 2019 ). Though not populous within the tissue, these cells maintain high proliferative capacity and can differentiate into osteoblasts, adipocytes, and chondrocytes in vitro ( Ferro et al, 2019 ). The origin of synovium-derived MSC (sMSC) in the synovial lining is still not fully defined, with groups supporting the notion of MSC infiltrating from resident vasculature or even from the neighboring bone marrow.…”