ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2011) 26 P323

Functional differences between visceral and subcutaneous fat pads originate in the adipose stem cell

G Cantini1, S Baglioni1, M Francalanci1, G Poli1, E Borgogni1, A Di Franco1, R Squecco1, F Francini1, M Lucchese2, G Perigli1, M Serio1 & M Luconi1

1University of Florence, Florence, Italy; 2AOU Careggi, Florence, Italy.

Metabolic pathologies mainly originate from dysfunctions of the white adipose tissue (AT). Functional differences in AT and their impact on metabolism seem associated with the fat depot regional distribution, in particular the subcutaneous (SAT) and visceral (VAT) pads. Human adult adipose stem cell (ASC) populations have recently been characterized from SAT and VAT. In this study, using human ASC cultures obtained from paired biopsies of abdominal SAT, S-ASC, and VAT, V-ASC, we addressed the question whether the functional differences observed between the two compartments may be already present in the adipose stem cell instead of being restricted to mature adipocytes. V-ASC showed significantly greater dimensions than the corresponding S-ASC, as evaluated by Millipore Scepter (mean diameter: 23.4±4.8 μm, V-ASC and 20.5±3.9 μm, S-ASC, P<0.005) and by electrophysiology path clamping. Investigating the ability of ASC to proliferate in vitro a statistically significant difference in the proliferation rate between the two paired populations was observed, being S-ASC growth rate significantly higher than the one observed in V-ASC, as evaluated by cell counting, Ki67 immunostaining, MTS and bromodeoxyuridine incorporation (mean fold increase respectively of 2.55, 2.07, 2.33 and 1.63, P<0.001). Following 3 weeks of in vitro-induced adipogenic differentiation performed in parallel conditions on V-ASC and S-ASC, S-ASC demonstrated a significantly higher adipogenic potential, as evaluated by Adipored staining of intracellular lipids (mean fold increase absorbance S- versus V-adipocytes: 1.83±0.09, P<0.001), as also confirmed by a significantly higher expression in in vitro differentiated adipocytes of adipogenic genes and proteins such as PPARgamma, adiponectin, FABP4. Our findings strongly suggest that VAT and SAT functional differences already originate in the adult adipose stem cell, which maintains the memory of the fat pad of origin.