Endothelial progenitor cells (EPCs) are key for angiogenic responses in multiple tissues and mediate a coordinate augmentation of the capillary network as adipose tissue (AT) expands in response to positive energy balance. However, isolation and culture of EPCs from human AT has been difficult. Here we describe a new method for obtaining well-characterized EPCs from human AT. Subcutaneous and visceral AT specimens (approximately 1-2 g) were obtained from 10-20 obese subjects by needle biopsy of abdominal subcutaneous AT and removal of omental AT fragments during abdominal surgery, respectively. Human EPCs were isolated from both the digested (SVCI) and undigested (SVCII) stromal vascular fractions of AT by anti-CD31 beads. After 5 days of in vitro culture, EPCs from SVCII exhibited an endothelial-like cobblestone morphology as compared to EPCs from SVCI. Flow cytometry analysis showed that the percentage of CD31+ and CD144+ cells was much higher in the SVCII compared to SVCI fraction (SVCII: CD31 97.9±2.9%, CD144 93.3±4.7%; SVCI: CD31 4.0±1.2%, CD144 3.8±0.7%). Immunofluorescence staining demonstrated that CD31+ EPCs from SVCII expressed Von Willebrand Factor (vWF) and VE-cadherin. Additionally, significantly higher mRNA and protein levels of CD31, E-selectin, e-NOS, VEGFR, and CD34 were found in CD31+ EPCs from SVCII than in control cells (CD31- cells from SVCI). EPCs from SVCII maintained the expression of endothelial markers (CD144 mRNA and protein levels) up to the fourth cell passage. Lastly, CD31+ EPCs from SVCII, but not control cells, were able to form tubes in 3D scaffolds (Matrigel) resembling capillary structures, as well as to incorporate acetylated LDL in vitro. Thus, we have successfully isolated EPCs with high proliferative potential and specific functional properties from the human AT. This will potentially increase our understanding of AT biology particularly in relation to altered expansion of distinct AT depots in human obesity.

Disclosure

C. Caccioppoli: None. S. Perrini: None. V. Genchi: None. R. Doria: None. G. Palma: None. A. Cignarelli: None. A. Natalicchio: Speaker’s Bureau; Self; AstraZeneca, Boehringer Ingelheim International GmbH, Lilly Diabetes, Sanofi. L. Laviola: Advisory Panel; Self; A. Menarini Diagnostics, Abbott, AstraZeneca, Lilly Diabetes, Novo Nordisk Inc., Roche Diabetes Care, Sanofi-Aventis, Speaker’s Bureau; Self; Boehringer Ingelheim International GmbH, Medtronic. F. Giorgino: Consultant; Self; AstraZeneca, Boehringer Ingelheim International GmbH, Lilly Diabetes, Novo Nordisk, Roche Diabetes Care, Sanofi, Research Support; Self; Lilly Diabetes, Roche Diabetes Care.

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