DNA methylation profile of different clones of human adipose stem cells does not allow to predict their differentiation potential.

Human adipose stem cells can differentiate into various mesodermic lineages, including adipogenic, osteogenic, chondrogenic, myogenic and endothelial pathways. In addition, these cells types possess immunomodulatory properties, potentially useful for autoimmune and autoinflammatory diseases. However, single-cell expanded clones have shown that the cells can present a variety of differentiation potential, which may be partly due to epigenetic differences among them. The objective of this study was to assess if DNA methylation plays a role in the differentiation potential observed between different cell clones obtained from the same donor. To this end, the methylation profile of five clonal cell lines of human adipose stem cells obtained by liposuction from two donors was analyzed. Previous reports demonstrated that cell lines 1.7 and 1.22 from Donor 1 and 3.5 from Donor 3 were adipogenic-osteogenic, but not cell lines 1.10 and 3.10. The genes analyzed were neuronal, endothelial, myogenic, osteogenic, adipogenic, extracellular matrix, cell cycle, cytoskeleton and metabolic enzymes. All clones analyzed in this study displayed a similar pattern of methylation in most of the gene families: 85.5% were hypomethylated genes and 14.5% hypermethylated. In conclusion, the methylation pattern of the 1113 genes studied in this report was not a consistent tool to identify the differentiation potential of human adipose stem cells.

Sunflower Oil but Not Fish Oil Resembles Positive Effects of Virgin Olive Oil on Aged Pancreas after Life-Long Coenzyme Q Addition.

An adequate pancreatic structure is necessary for optimal organ function. Structural changes are critical in the development of age-related pancreatic disorders. In this context, it has been reported that different pancreatic compartments from rats were affected according to the fat composition consumed. Since there is a close relationship between mitochondria, oxidative stress and aging, an experimental approach has been developed to gain more insight into this process in the pancreas. A low dosage of coenzyme Q was administered life-long in rats in order to try to prevent pancreatic aging-related alterations associated to some dietary fat sources. According to that, three groups of rats were fed normocaloric diets containing Coenzyme Q (CoQ) for two years, where virgin olive, sunflower, or fish oil was included as unique fat source. Pancreatic samples for microscopy and blood samples were collected at the moment of euthanasia. The main finding is that CoQ supplementation gives different results according to fat used in diet. When sunflower oil was the main fat in the diet, CoQ supplementation seems to improve endocrine pancreas structure and in particular ß-cell mass resembling positive effects of virgin olive oil. Conversely, CoQ intake does not seem to improve the structural alterations of exocrine compartment previously observed in fish oil fed rats. Therefore CoQ may improve pancreatic alterations associated to the chronic intake of some dietary fat sources.

Negative neuronal differentiation of human adipose-derived stem cell clones.

AIMS: Adipose mesenchymal stem cells are a heterogeneous population. Therefore, the question posed in this study is whether the heterogenic differentiation potential exhibited by the different clones toward mesodermic lineages can be extended to nonmesodermic lineages, such as the neuroectoderm. MATERIALS & METHODS: Different single cell clones of human adipose mesenchymal stem cells from the same donor were isolated. Neuronal plasticity of the clones was assessed according to the pattern DNA methylation, gene expression and intracellular calcium responses. RESULTS: Under neurogenic culture conditions, clones presented variable expression of neuronal-specific genes, but still expressed osteogenic markers. No calcium response was exhibited in response to KCl incubation. The DNA methylation profile presented a very similar pattern in neuroectoderm gene promoters. CONCLUSIONS: Data indicate that there are no significant differences between the undifferentiated and supposedly neuronal-differentiated mesenchymal cells.

Comparative analysis of pancreatic changes in aged rats fed life long with sunflower, fish, or olive oils.

An adequate pancreatic structure is necessary for optimal organ function. Structural changes are critical in the development of age-related pancreatic disorders. We aimed to study the effect of oil consumption on pancreas histology in order to find aging-related signs. To this end, three groups of rats were fed an isocaloric diet for 2 years, where virgin olive, sunflower, or fish oil was included. Pancreatic samples for microscopy and blood samples were collected at the moment of sacrifice. As a result, the sunflower oil-fed rats presented higher ß-cell numbers and twice the insulin content than virgin olive oil-fed animals. In addition, rats fed with fish oil developed acinar fibrosis and macrophage infiltrates in peri-insular regions, compared with counterparts fed with virgin olive oil. Inflammation signs were less prominent in the sunflower group. The obtained data emphasize the importance of dietary fatty acids in determining pancreatic structure.

Phenotypic differences during the osteogenic differentiation of single cell-derived clones isolated from human lipoaspirates.

Osteogenic precursors can be obtained from mesenchymal stem cells, which can be isolated from different sources, including adipose tissue. Optimal osteogenic differentiation in in vitro conditions and the selection of the potential precursors that could be further used in bone regeneration still have two main questions left to solve, viz. the heterogeneity of the mesenchymal cell population and the presence of a basal transcription level of several characteristic genes of the osteogenic lineage, which makes rapid and effective comparisons during cell differentiation difficult. Single-cell clones were isolated and expanded from human lipoaspirate cells. Osteogenic differentiation was induced and studied in defined media, using four representative isolated cell clones showing differences in the basal expression of a set of characteristic osteogenic genes. The clones showing a low constitutive expression of these genes were able to display comparatively higher levels of mineralization. In addition, the cells from these clones displayed a characteristic pattern of bundle fibres of collagen during osteogenic induction and showed a higher potency to differentiate towards the adipogenic lineage. These results demonstrate that specific multipotent precursors can be isolated from human lipoaspirate cells with a higher differentiation potential, allowing the maturation of specific lineages in a shorter time. These results additionally demonstrate that, since the basal expressions of the several genes were used as osteogenic markers, a phenotypic biochemical analysis should always be utilized to study optimal osteogenesis conditions. Copyright © 2010 John Wiley & Sons, Ltd.