Influence of glucose and insulin in human adipogenic differentiation models with adipose-derived stem cells.

Abstract

Autologous fat grafting represents an attractive source for tissue engineering applications in the field of reconstructive medicine. However, in adipogenic differentiation protocols for human adiposederived stem cells, the concentration of glucose and insulin varies considerably. With the intent to gain maximum tissue augmentation, we focused on the late phase of adipogenesis. In this study, we modified the differentiation protocol for adipose-derived stem cells by prolongation of the induction period and the application highly concentrated glucose and insulin. Human adipose-derived stem cells were isolated from subcutaneous depots and differentiated in a standard induction medium for the first two weeks, followed by two weeks with varying glucose and insulin concentrations. Morphological changes assessed using Oil-RedO staining were examined for corresponding alterations in the expression of the adipogenic markers peroxisome proliferator-activated receptor gamma (PPARγ) and lipoprotein lipase (LPL). Furthermore, glucose and lactate levels in conditioned media were monitored over the period of differentiation. We found high-glucose media increasing the level of lipid accumulation and the size of single droplets whereas insulin significantly showed a dosedependent negative effect on fat storage. However, whereas high glucose stimulated PPARγ transcription, expression levels in insulin-treated cells remained constant. Results permit assumptions that a high-glucose medium intensifies the degree of differentiation in mature adipocytes providing conditions to promote graft volume while we have identified highly concentrated insulin treatment as an inhibitor of lipid storage in the late adipogenic differentiation.

Insulin negatively regulates dedifferentiation of mouse adipocytes in vitro

“…Insulin binds to its receptor and then triggers the phosphorylation of IRS, which, in turn, recruits and sequentially activates PI-3K and AKT [14,15], which plays important roles in adipose biology [37,38]. Although insulin is known to stimulate adipocyte differentiation dose-dependently at the early stage of differentiation [39], Konneker et al recently reported that high concentration of insulin (>3.4 μM) inhibits lipid storage in the late phase of human primary preadipocytes differentiation [40]. Similar result was also can be found in a previous report that long-term exposure to insulin eliciting a more immature phenotype in 3T3-L1 adipocytes [41].…”

Application of a deep learning-based image analysis and live-cell imaging system for quantifying adipogenic differentiation kinetics of adipose-derived stem/stromal cells

“…Lipid droplets can combine to form larger droplets, and adipocytes and hepatocytes can contain giant lipid droplets [ 12 ]. Lipid droplet formation and accumulation are processes that can be monitored using morphological data obtained through conventional microscopy [ 13 ]. The generation of lipids during adipogenesis is a complex process regulated by the gene expression of peroxisome proliferator-activated receptor γ ( PPARG), CEBPA/CEBPB [ 14 ] and ADIPOQ , which leads to the production of adiponectin, an adipokine involved in adipocyte differentiation [ 15 ].…”

High-throughput drug screening models of mature adipose tissues which replicate the physiology of patients’ Body Mass Index (BMI)

“…This was also the case for the fatty acids uptake measurements of 13 different patients ( Appendix A , Appendix A ). This reduced mature adipocyte sensitivity can be a bias from the in vitro culture condition where culturing the mature adipocytes in DMEM high glucose medium for 2 weeks might induce their insulin resistance [ 55 , 56 ]. This model still allows to get, after 7 days of culture, a reliable tool for assessing drugs acting on the glucose/fatty acids uptakes or the glycerol release in the obesity fighting strategy.…”