Regulation of osteogenic differentiation of human adipose-derived stem cells by controlling electromagnetic field conditions

Many studies have reported that an electromagnetic field can promote osteogenic differentiation of mesenchymal stem cells. However, experimental results have differed depending on the experimental and environmental conditions. Optimization of electromagnetic field conditions in a single, identified system can compensate for these differences. Here we demonstrated that specific electromagnetic field conditions (that is, frequency and magnetic flux density) significantly regulate osteogenic differentiation of adipose-derived stem cells (ASCs) in vitro. Before inducing osteogenic differentiation, we determined ASC stemness and confirmed that the electromagnetic field was uniform at the solenoid coil center. Then, we selected positive (30/45 Hz, 1 mT) and negative (7.5 Hz, 1 mT) osteogenic differentiation conditions by quantifying alkaline phosphate (ALP) mRNA expression. Osteogenic marker (for example, runt-related transcription factor 2) expression was higher in the 30/45 Hz condition and lower in the 7.5 Hz condition as compared with the nonstimulated group. Both positive and negative regulation of ALP activity and mineralized nodule formation supported these responses. Our data indicate that the effects of the electromagnetic fields on osteogenic differentiation differ depending on the electromagnetic field conditions. This study provides a framework for future work on controlling stem cell differentiation.

Comparative Analysis about the Effect of Isolated Phosphatidylcholine and Sodium Deoxycholate for the Viability of Adipocyte

PURPOSE: Lipobean(R)s, widely used in lipodissolving techniques, contain phosphatidylcholine and sodium deoxycholate as its main substances. They have been approved only as medication for liver disease by the FDA. However, they have been used under various clinical settings without exact knowledge of its action mechanism. The authors designed an in vitro study to analyze the effects of different concentrations of phosphatidylcholine and sodium deoxycholate on adipocytes and other types of cells. METHODS: Human adipose-derived stem cell were cultured and induced to differentiate into adipocytes. Fibroblasts extracted from human inferior turbinate tissue, and MC3T3-E1 osteoblast lines were cultured. Phosphatidylcholine solution dissolved with ethanol was applied to the culture medium at differing concentrations (1, 4, 7, 10 mg/mL). The sodium deoxycholate solution dissolved in DMSO applied to the medium at differing concentrations (0.07, 0.1. 0.4. 0.7 mg/mL). Cells were dispersed at a concentration of 5 x 10(3) cells/well in 24 well plates, and surviving cells were calculated 1 day after the application using a CCK-8 kit. RESULTS: The number of surviving cells of adipocytes, fibroblasts and osteoblasts decreased as the concentration of sodium deoxycholate increased. However, all types of cells that had been processed in a phosphatidylcholine showed a cell survival rate of over 70% at all concentrations. CONCLUSION: This study shows that sodium deoxycholate is the more major factor in destroying adipocytes, and it is also toxic to the other cells. Therefore, we conclude that care must be taken when using Lipobean(R)s as a method of reducing adipose tissue, for its toxicity may destroy other nontarget cells existing in the subcutaneous tissue layer.