The Role of Dissolved Oxygen Levels on Human Mesenchymal Stem Cell Culture Success, Regulatory Compliance, and Therapeutic Potential

Abstract

Most cells in the human body, including human mesenchymal stem cells (hMSCs), have evolved to survive and function in a low physiological oxygen (O) environment. Investigators have become increasingly aware of the effects of O levels on hMSC biology and culture and are mimicking the natural niche of these cells in vitro to improve cell culture yields. This presents many challenges in relation to hMSC identity and function and in the maintenance of a controlled O environment for cell culture. The aim of this review was to discuss an "hMSC checklist" as a guide to establishing which identity and potency assays to implement when studying hMSCs. The checklist includes markers, differentiation potential, proliferation and growth, attachment and migration, genomic stability, and paracrine activity. Evidence drawn from the current literature demonstrates that low O environments could improve most "hMSC checklist" attributes. However, there are substantial inconsistencies around both the terminology and the equipment used in low O studies. Therefore, "hypoxia" as a term and as a culture condition is discussed. The biology of short-term (acute) versus long-term (chronic) hypoxia is considered, and a nascent hypothesis to explain the behavior of hMSCs in long-term hypoxia is presented. It is hoped that by establishing an ongoing discourse and driving toward a regulatory recognizable "hMSC checklist," we may be better able to provide the patient population with safe and efficacious regenerative treatments.

The impact of cryopreservation on bone marrow-derived mesenchymal stem cells: a systematic review

“…From the 41 retained studies, information regarding the freezing solution composition, the freezing protocol, the duration of storage, the concentration of cells at freezing, the passage number at freezing as well as the thawing method was extracted and tabulated. Next, studies were grouped in tables according to the “hMSC checklist” proposed in [24]. Cell surface marker expression, differentiation potential, proliferation and growth, attachment and migration potential, genomic stability and paracrine function were examined.…”

Polydopamine and collagen coated micro-grated polydimethylsiloxane for human mesenchymal stem cell culture

“…Their therapeutic potential has been proved in diverse tissue engineering applications such as wound healing [ 27 ], bone regeneration [ 28 ], small diameter vascular graft fabrication [ [29] , [30] , [31] ], and cardiac repair [ 32 ]. Moreover, previous studies have shown that physiologically low (2%) oxygen preserves the stemness and paracrine effects of hMSCs [ [33] , [34] , [35] ]. Therefore, in this study, hMSCs were selected as model cells to further examine their cellular response toward PD based surface coatings under the physiological hypoxic environment.…”

Determining Conditions for Successful Culture of Multi-Cellular 3D Tumour Spheroids to Investigate the Effect of Mesenchymal Stem Cells on Breast Cancer Cell Invasiveness

“…Similar to cancer cells, it has been found that hMSC proliferation, migratory capacity, and function can be enhanced in hypoxic conditions. It is reported that low O 2 percentages (3%) can stimulate a greater yield of hMSCs when cells are cultured in low oxygen for a number of days [23], and can significantly enhance proliferative ability by approximately 10 population doublings compared to ambient O 2 levels (20%) [24]. Therefore, from the wider literature, it can be seen that both cancer cells and hMSCs can thrive in hypoxic conditions in vitro, where other mammalian cells would perish.…”