Growth, Metabolism, and Growth Inhibitors of Mesenchymal Stem Cells

Abstract

Most therapeutic applications of bone marrow stromal cells (MSCs), or mesenchymal stem cells, require expansion of these cells. This study aimed to obtain more information about human MSCs regarding their expansion characteristics: growth, metabolism, and growth inhibitors. In addition, the same expansion factors were examined for (model species) goat and rat MSCs to evaluate differences between MSCs of mammalian species. MSC proliferation, nutrient consumption, and metabolite production were determined for five donors per species. In addition, the growth inhibitory concentrations of lactate and ammonia (NH3) were established. Results showed that goat MSCs grew significantly faster than human and rat MSCs and that goat cells metabolized glucose more efficiently into energy (Ylac/glc=0.8) than human (Ylac/glc=2.0) and rat MSCs (Ylac/glc=1.9). In addition, human (qGlc= -9.2pmol cell(-1) day(-1) and rat MSCs (qGlc= -5.9pmol cell(-1) day(-1)) consumed more glucose than goat MSCs (qGlc= -2.6pmol cell(-1) day(-1)). Glutamine was shown not to be important as energy source for human, goat, and rat MSCs. Regarding growth inhibition by metabolites, rat MSCs were more sensitive to lactate and NH3 (growth inhibiting at 16mM lactate and at 1.9mM NH3) than goat (lactate: 28.4mM, NH3: 2.9mM) and human MSCs (lactate: 35.4mM, NH3: 2.4mM). Human MSCs did not lose their differentiation potential when their growth was inhibited by lactate or NH3.

Production Process for Stem Cell Based Therapeutic Implants: Expansion of the Production Cell Line and Cultivation of Encapsulated Cells

“…Growth, oxygen and glucose consumption kinetics were determined by fitting of the model parameters to the experimental data. Glutamine wasn't considered since it is an unimportant energy source for hMSC [16]. The modeled curves for a 60 cm 3 scale are exemplarily shown in Figure 7.…”

“…The growth and consumption rates are comparable to those reported in the literature. Glucose consumption and growth rates of human mesenchymal stem cells are referred to be (0.23 -1.22) x 10 -7 mg/h/cell [17,18] and 0.33 -0.94 1/d [15,16,[19][20][21][22], respectively. Oxygen consumption rates of (1.22 -3.20) x 10 -8 mg/h/cell are reported for various human cell types [23][24][25][26][27].…”

Effects of L-lactic acid and D,L-lactic acid on viability and osteogenic differentiation of mesenchymal stem cells

“…Yet, if we tentatively set 75% as the threshold, the tolerant concentrations for both L-lactic acid and L,D-lactic acid are between 10-20 mmol/L according to our examinations of rat MSCs, and additions of 40 mmol/L lactic acids resulted in decrease of ALP activity more than 50% relative to the blank control ( Figure 6). In a previous study of growth inhibitors including lactic acids (lack of the groups of medium pH, salt, lactate, and D,L-lactic acids), Schop et al [44] indicated the cell-type dependence of the response to L-lactic acids: rat MSCs was inhibited at 16 mmol/L and human MSCs at 35.4 mmol/L. So, human cells are more tolerant to lactic acids.…”

“…How to decouple these three factors and determine the main one is an important topic, although some single factors have been examined [43,44]. Another fundamental question is the possible difference of cell responses between the two optical isomers of lactic acids.…”

Cartilage resurfacing potential of PLGA scaffolds loaded with autologous cells from cartilage, fat, and bone marrow in an ovine model of osteochondral focal defect

“…Glucose and lactate concentrations in supernatants were determined using an YSI 2700 automated analyser (Yellow Springs Instruments). Generation time (t d , days), cell growth rate (l, days -1 ), specific consumption (q Glc , nmol/10 6 cells/h) and production rates (q lac , nmol/10 6 cells/h) of extracellular metabolites (glucose and lactate, respectively) were calculated as described elsewhere (Schop et al 2009). ASC, MSC and chondrocyte progenitors were cultured in low glucose DMEM medium supplemented with streptomycin (0.167 g/L, SigmaAldrich), kanamycin (0.075 g/L, Sigma-Aldrich) and 10 % FCS.…”