The Influence of Hypoxia and Fibrinogen Variants on the Expansion and Differentiation of Adipose Tissue-Derived Mesenchymal Stem Cells

Abstract

Upon implantation of tissue-engineered scaffolds, hypoxia will occur until neovascularization takes place. In vivo, the temporary fibrin matrix forms a suitable matrix for this process and fibrin variants can influence the extent of neovascularization. In this study, the influence of oxygen tension and naturally occurring fibrinogen variants on adipose tissue-derived mesenchymal stem cell (ASC) expansion and differentiation were determined. ASC proliferated 1.7-fold faster in 1% oxygen and showed reduced cell aging, and their stemness was preserved. The stem cell surface marker expression was similar in 1% and 20% oxygen. The various fibrinogen coatings did not influence ASC expansion and differentiation. Differentiation of ASC toward adipogenic and osteogenic lineages was improved in 20% oxygen, whereas 1% oxygen improved chondrogenic differentiation. In conclusion, optimal oxygen concentrations vary for the intended ASC application, and fibrinogen variants, which can be used to influence neovascularization, do not alter ASC behavior. These data emphasize the importance of oxygen concentrations during stem cell growth and differentiation.

Human bone marrow stem cells cultured under hypoxic conditions present altered characteristics and enhanced in vivo tissue regeneration

“…In particular, the proliferation and CFU potency of hBMSCs expanded under hypoxia were not increased compared to those observed under normoxia. Several researchers have demonstrated that hypoxia enhances the in vitro expansion rate [23,24]; however, there are other studies with similar findings to those presented here, such as an O 2 concentration of 1% or less appearing to reduce the proliferation of MSCs [25]. Within the scope of the present experiments, it was assumed that a very low oxygen level can suppress the proliferation and CFU potency of hBMSCs; these tendencies, and their discrepancy with the results of several previous studies, may be related to the effect of the hypoxic condition on cellular senescence.…”

“…Within the scope of the present experiments, it was assumed that a very low oxygen level can suppress the proliferation and CFU potency of hBMSCs; these tendencies, and their discrepancy with the results of several previous studies, may be related to the effect of the hypoxic condition on cellular senescence. Cellular proliferation could be reduced at early passages, but the pattern might be reversed in cells at later passages (long-term culture) [23,24]. Cells cultured in a hypoxic condition showed decreased expression of apoptosis/ senescence-related genes [Apo1 (apoptosis antigen-1, also known as the FAS receptor) and p21 (regulator of cell cycle progression at the G1 and S phases; functions in cellular growth arrest)], and the proliferative potential could be maintained even in long-term culture passages.…”

Expression, Regulation and Function of Human Metallothioneins in Endothelial Cells

“…Cell culture under hypoxic conditions was performed as described previously [16]. In brief, MVEC were first stimulated with 10 ng/ml vascular endothelial growth factor (VEGF; Invitrogen) for 24 h. Subsequently, both MVEC and HUVEC were cultured for 24 h in 1% O 2 , 5% CO 2 and 37°C inside a custom-designed hypoxic workstation (T.C.P.S.).…”

The role of stem cells in adipose tissue remodeling.

“…Since oxygen has a limited diffusion capacity in which it can only supply cells within a close proximity to a functional capillary bed, such an increase in adipocyte area creates a hypoxic environment in obese adipose tissue (58,(185)(186)(187). Hypoxic conditions have been shown to inhibit adipogenic differentiation of mesenchymal stem cells (MSCs) from bone marrow and adipose tissue (188)(189)(190)(191). Hypoxia also has an effect on the endocrine function of adipose tissue, suppressing production of adiponectin by adipocytes (185,186,192,193).…”