Characterization of human adult stem cell populations isolated from subcutaneous and visceral adipose tissue
Silvana Baglioni1, Michela Francalanci1, Roberta Squecco2, Adriana Lombardi1, Giulia Cantini1, Roberta Angeli3, Stefania Gelmini1, Daniele Guasti4, Susanna Benvenuti1, Francesco Annunziato3, Daniele Bani4, Francesco Liotta3, Fabio Francini2, Giuliano Perigli5, Mario Serio1 & Michaela Luconi1
White adipose tissue acts as an endocrine organ that secretes a variety of adipokines and coordinates a number of biological processes such as energy homeostasis, neuroendocrine and immune functions. Recent studies demonstrated that abundant adipose tissue depots (particularly visceral adipose tissue), by producing inflammatory cytokines, contribute to chronic low-grade inflammation processes which may underlie the pathogenesis of metabolic disorders such as obesity, atherosclerosis, insulin-resistance and diabetes. Functional differences in adipose tissue seem associated with the regional distribution of fat depots, in particular in subcutaneous and visceral omental pads.
The aim of our study was to obtain a human cell model that provides an useful system for the in vitro investigation of the pathophysiological processes leading to differentiation of mature adipocyte. For the first time we isolated human adipose-derived adult stem cells from visceral and subcutaneous abdominal fat (V-ASC and S-ASC, respectively) from the same subject. Flow cytometry immunophenotyping shows that plastic culturing selects homogeneous cell populations of V-ASC and S-ASC sharing typical markers of mesenchymal stem cells. Electron microscopy, electrophysiological analysis of cell currents and quantitative real time RT-PCR analysis of the expression of stemness markers confirm the mesenchymal stem nature of both V-ASC and S-ASC. Similarly to S-ASC, when cultured in the appropriate inducing media, V-ASC can differentiate not only towards adipogenic, osteogenic and chondrogenic lineages, but also towards muscle and neuronal cells, as demonstrated by immunofluorescence, quantitative real time RT-PCR and electrophysiological analyses, suggesting the multipotency of such adult stem cells.
In conclusion both visceral and subcutaneous adipose tissues are a source of pluripotent stem cells with multi-germline potential. However, the viscerall rather than the subcutaneous adipose-derived adult stem cell populations could represent a more appropriate in vitro cell model for investigating the molecular mechanisms implicated in the pathophysiology of metabolic disorders such as obesity.