Adipose-derived mesenchymal stromal/stem cells: An update on their phenotype in vivo and in vitro

Abstract

Adipose tissue is a rich, ubiquitous and easily accessible source for multipotent stromal/stem cells and has, therefore, several advantages compared to other sources of mesenchymal stromal/stem cells. Several studies have tried to identify the origin of the stromal/stem cell population within adipose tissue in situ. This is a complicated attempt because no marker has currently been described which unambiguously identifies native adipose-derived stromal/stem cells (ASCs). Isolated and cultured ASCs are a non-uniform preparation consisting of several subsets of stem and precursor cells. Cultured ASCs are characterized by their expression of a panel of markers (and the absence of others), whereas their in vitro phenotype is dynamic. Some markers were expressed de novo during culture, the expression of some markers is lost. For a long time, CD34 expression was solely used to characterize haematopoietic stem and progenitor cells, but now it has become evident that it is also a potential marker to identify an ASC subpopulation in situ and after a short culture time. Nevertheless, long-term cultured ASCs do not express CD34, perhaps due to the artificial environment. This review gives an update of the recently published data on the origin and phenotype of ASCs both in vivo and in vitro. In addition, the composition of ASCs (or their subpopulations) seems to vary between different laboratories and preparations. This heterogeneity of ASC preparations may result from different reasons. One of the main problems in comparing results from different laboratories is the lack of a standardized isolation and culture protocol for ASCs. Since many aspects of ASCs, such as the differential potential or the current use in clinical trials, are fully described in other recent reviews, this review further updates the more basic research issues concerning ASCs' subpopulations, heterogeneity and culture standardization.

Comparison of human platelet lysate alternatives using expired and freshly isolated platelet concentrates for adipose-derived stromal cell expansion

“…Studies have found that the immunophenotypic profiles differ significantly between ASCs derived from different donors, between ASCs obtained from different tissue sources, between ASC populations at different passages and to a large extent between individual cells within a given ASC population (52)(53)(54)(55)(56). To date, no immunophenotypic marker has been identified that is specific to ASCs.…”

Strategies for Bioengineered Scaffolds that Support Adipose Stem Cells in Regenerative Therapies

“…ASCs share many similarities with BM-MSCs including their potential to develop into similar cell lineages and have no clear distinction between the populations in terms of surface marker or gene expression [16,[20][21][22][23]. It has been suggested that ASCs can be distinguished from BM-MSCs by their expression of CD36 (F.A.T.…”

Stem cells and chronic wound healing: state of the art

“…5 The inconstant nature of surface marker expression as these cells are removed from their native environment and expanded ex vivo merely worsens the surrounding controversy. 6 Lack of standardization can thereby impede our ability to draw comparisons across studies. Despite these shortcomings, MSCs are understood to play a significant role in coordinating the wound healing response as it advances through phases of inflammation, proliferation, and remodeling.…”