Differentiation Potential And Tumorigenic Risk of Rat Bone Marrow Stem Cells Are Affected By Long-Term In Vitro Expansion

Abstract

Mesenchymal stem cells (MSCs) have the capacity for extensive expansion and adipogenic, osteogenic, chondrogenic, myogenic, and neural differentiation in vitro. The aim of our study was to determine stemness, differentiation potential, telomerase activity, and ultrastructural characteristics of long-term cultured rat bone marrow (rBM)-MSCs. Materials and Methods: rBM-MSCs from passages 3, 50, and 100 (P3, P50, and P100) were evaluated through immunocytochemistry, reverse transcription-polymerase chain reaction, telomerase activity assays, and electron microscopy. Results: A dramatic reduction in the levels of myogenic markers actin and myogenin was detected in P100. Osteogenic markers Coll1, osteonectin (Sparc), and osteocalcin as well as neural marker c-Fos and chondrogenic marker Coll2 were significantly reduced in P100 compared to P3 and P50. Osteogenic marker bone morphogenic protein-2 (BMP2) and adipogenic marker peroxisome proliferatoractivated receptor gamma (Pparγ) expression was reduced in late passages. The expression of stemness factor Rex-1 was lower in P100, whereas Oct4 expression was decreased in P50 compared to P3 and P100. Increased telomerase activity was observed in longterm cultured cells, signifying tumorigenic risk. Electron microscopic evaluations revealed ultrastructural changes such as smaller number of organelles and increased amount of autophagic vacuoles in the cytoplasm in long-term cultured rBM-MSCs. Conclusion: This study suggests that long-term culture of rBM-MSCs leads to changes in differentiation potential and increased tumorigenic risk.

Stem Cells and the Microenvironment: Reciprocity with Asymmetry in Regenerative Medicine

“…A first problem is represented by the reduced capacity to proliferate and differentiate in vitro: this is the case of adult stem cells, which proliferate and differentiate only in their specific tissue microenvironment (Scadden 2006;Votteler et al 2010). Furthermore, recent studies conducted on mice and cohorts of patients have indicated that adult mesenchymal and hematopoietic (Karaöz and Tepeköy 2019;Molina et al 2019), embryonic (Blum and Benvenisty 2008;Fujimori et al 2012), and induced pluripotent stem cells (Kamada et al 2014) are associated to a tumorigenic risk. For example, embryonic stem cells and induced pluripotent stem cells could give rise to teratomas, which are tumor-like formations consisting of tissues of the three germ layers (Nussbaum et al 2007;Hentze et al 2009).…”

Immunoregulatory therapy strategies that target cytokine storms in patients with COVID‑19 (Review)

“…Indeed, at least 20 COVID-19 clinical trials using MSCs are ongoing (Table III). Although most preclinical studies on the immune effects of MSCs have shown benefits, further studies are required to evaluate the safety of MSC transplantation, particularly with regard to potential tumorigenic effects (56).…”