Functional Differences in Visceral and Subcutaneous Fat Pads Originate from Differences in Adipose Stem Cells
Gabriella Nesi, Silvana Baglioni, Milena Paglierani, Giulia Cantini, Giada Poli, Gianni Forti, Michaela Luconi. University of Florence, Florence, Italy
Background: Metabolic pathologies mainly originate from adipose tissue (AT) dysfunction. AT functional differences associate with the anatomic distribution of fat depots in subcutaneous (SAT) and visceral (VAT) pads. We address the question as to whether the differences between the two compartments may be seen early in the adipose stem cell (ASC) and not just in mature adipocytes.
Design: We assessed proliferation/differentiation of ASC from paired abdominal SAT-(SASC) and VAT-(V-ASC) biopsies in parallel. Growth rate was evaluated by MTS assay, cell counting and bromodeoxyuridine incorporation and then confirmed by Ki67 immunostaining. Adipogenesis induced in vitro from ASC populations was assayed through expression of adipogenic markers by TaqMan, Western blot and immunofluorescence analyses.
Results: A statistically significant difference between the two ASC populations was observed in the proliferation rate and adipogenic potential, with S-ASC displaying a growth rate (Ki67% mean±SE nuclear staining: S-ASC, 67.7±15.1 vs. V-ASC, 32.7±7.7, P<0.001, n=4 different ASC populations) and adipogenic potential (mean±SE adiponectin vs. GAPDH reference gene TaqMan expression: S-adipocytes, 274500±75000 vs. V-adipocytes, 39000±17400, P<0.005, n=30 differentiated populations) higher than V-ASC, consequently giving rise to better organised, functional adipocytes. The higher ability to secrete adiponectin and the lower susceptibility to lipolysis of S-ASC derived adipocytes accounted for the metabolic differences observed in the various adipose tissue depots.
Conclusions: Our findings strongly suggest that VAT and SAT functional differences occur early in adult ASC which keeps the memory of the original fat pad. Such differences in the stem cell may render the adipose depots variably susceptible to dysfunction and cause a differential involvement of the two compartments in the development of metabolic pathologies, leading the way to possible targets for specific therapeutic approaches.
Wednesday, March 21, 2012 9:30 AM
Poster Session V # 285, Wednesday Morning