Inability of Low Oxygen Tension to Induce Chondrogenesis in Human Infrapatellar Fat Pad Mesenchymal Stem Cells.

Samia Rahman,Nadr M Jomha,Melanie Kunze,Aillette Mulet-Sierra,Yan Liang,Victoria Goncalves,Adetola B Adesida,Adetola B Adesida,Adetola B Adesida,Alexander R A Szojka

doi:10.3389/fcell.2021.703038

Abstract

ObjectiveArticular cartilage of the knee joint is avascular, exists under a low oxygen tension microenvironment, and does not self-heal when injured. Human infrapatellar fat pad-sourced mesenchymal stem cells (IFP-MSC) are an arthroscopically accessible source of mesenchymal stem cells (MSC) for the repair of articular cartilage defects. Human IFP-MSC exists physiologically under a low oxygen tension (i.e., 1–5%) microenvironment. Human bone marrow mesenchymal stem cells (BM-MSC) exist physiologically within a similar range of oxygen tension. A low oxygen tension of 2% spontaneously induced chondrogenesis in micromass pellets of human BM-MSC. However, this is yet to be demonstrated in human IFP-MSC or other adipose tissue-sourced MSC. In this study, we explored the potential of low oxygen tension at 2% to drive the in vitro chondrogenesis of IFP-MSC. We hypothesized that 2% O2 will induce stable chondrogenesis in human IFP-MSC without the risk of undergoing endochondral ossification at ectopic sites of implantation.MethodsMicromass pellets of human IFP-MSC were cultured under 2% O2 or 21% O2 (normal atmosphere O2) in the presence or absence of chondrogenic medium with transforming growth factor-β3 (TGFβ3) for 3 weeks. Following in vitro chondrogenesis, the resulting pellets were implanted in immunodeficient athymic nude mice for 3 weeks.ResultsA low oxygen tension of 2% was unable to induce chondrogenesis in human IFP-MSC. In contrast, chondrogenic medium with TGFβ3 induced in vitro chondrogenesis. All pellets were devoid of any evidence of undergoing endochondral ossification after subcutaneous implantation in athymic mice.

Highlights

Articular cartilage is avascular and exists under a low oxygen tension microenvironment (LundOlesen, 1970; Brighton and Heppenstall, 1971a,b)
In vitro chondrogenic protocols for Infrapatellar fat pad (IFP)-mesenchymal stem cells (MSC) are either a direct transfer or a variant of protocols developed for bone marrow-derived mesenchymal stem cells (BM-MSC) and involve exogenous additions of TGFβ (Johnstone et al, 1998; Wickham et al, 2003; Khan et al, 2007; Buckley et al, 2011; Buckley and Kelly, 2012)
We explored a low oxygen tension of 2% as a driver of chondrogenic differentiation of infrapatellar fat pad MSC (IFP-MSC)

Summary

Introduction

Articular cartilage is avascular and exists under a low oxygen tension microenvironment (LundOlesen, 1970; Brighton and Heppenstall, 1971a,b). Hypoxia Fails to Induce Chondrogenesis factor for the early development of osteoarthritis (Muthuri et al, 2011). To this end, a variety of cell-based approaches including autologous chondrocyte implantation and multipotent mesenchymal stem cells (MSC) have been assessed to augment articular cartilage healing and mitigate the onset of osteoarthritis, in particular, knee osteoarthritis (Brittberg et al, 1994, 2001; Peterson et al, 2000; Hwang et al, 2011; Bornes et al, 2014, 2018; Mobasheri et al, 2014; Fellows et al, 2016). Several studies have demonstrated the in vitro chondrogenesis of adipose-derived MSC with growth factors (i.e., TGFβ1, TGFβ3, and BMP-6) in the absence or presence of low oxygen tension, no study has investigated the potential of low oxygen tension alone to drive the in vitro chondrogenesis of adipose-derived MSC (Zuk et al, 2001; Erickson et al, 2002; Awad et al, 2003; Huang et al, 2004; Wang et al, 2005; Estes et al, 2006; Afizah et al, 2007; Hennig et al, 2007; Khan et al, 2007; Malladi et al, 2007; Mehlhorn et al, 2007; Cheng et al, 2009; Kim and Im, 2009; Martinez-Lorenzo et al, 2009; Diekman et al, 2010; Merceron et al, 2010)

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