Primary cultures of isolated human adipose-derived adult stem (ADAS) cells are multipotent
and differentiate in vitro along the adipocyte, chondrocyte, neuronal, osteoblast,
and skeletal muscle pathways.
We examined the ADAS cell yield per unit volume of liposuction tissue, and their surface
protein phenotype by flow cytometry. Adipogenesis was assessed by Oil Red O staining
and ELISA analysis of leptin secretion.
The donor population was 87.5% female (n = 18) with a mean age (± SD) of 44 ± 10 years and body mass index (BMI) of 24.9 + 2.7. The mean cell yield was 404 000 ± 206 000 cells per milliliter of lipoaspirate (n = 18). Linear regression analysis of the cells derived from the female donors demonstrated
a significant negative correlation between the number of cells obtained per milliliter
of lipoaspirate with the BMI but not the age of the donor.
The undifferentiated ADAS cells were homogeneously positive for the cell-surface markers
CD10, CD13, CD29, CD44, CD49e, CD59, CD90, and HLA-ABC, and homogeneously negative
for the cell surface markers CD11b, CD45, and HLA-DR. The absence of the panhema-topoietic
marker, CD45, indicates that the ADAS cells do not derive from circulating BM hematopoietic
stem cells. Adipocyte differentiation led to a 5.1-fold increase in Oil Red O staining,
and a 196-fold increase in leptin secretion levels. Culture of the cells in the presence
of antibiotic and fungizone did not alter the undifferentiated ADAS cell immunophenotype
based on flow cytometry, or their adipocyte differentiation based on leptin secretion.
The ability to isolate a consistently homogeneous population of undifferentiated adult
stem cells from adipose tissue of multiple donors supports their potential utility
in future tissue-engineering applications.