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Loss of function studies has indicated that PPAR-γ is required for adipogenesis
both in vitro and in vivo. Thiazolidinediones (TZDs) act by binding to PPAR-γ,
thereby activating the protein cascade that affects metabolism as well as differentia-
tion capacity. The latter occurs by increasing adipogenesis and lipid accumulation
(Kelly et al. 1999 ; Schipper et al. 2008 ). It was demonstrated by Tchkonia and col-
leagues ( 2002 ) that preadipocytes isolated from subcutaneous adipose tissue had the
highest PPAR-γ activity, displayed the greatest effects of TZDs on differentiation,
and had the lowest amount of apoptosis compared to omental and visceral abdomi-
nal adipose deposits. These results suggested that ASCs isolated from subcutaneous
adipose tissue may be more suited to differentiate into mature adipocytes than vis-
ceral or omental adipose tissue (Tchkonia et al. 2002 ).
Schipper and co-workers ( 2008 ) compared the functional variability between
different anatomically located subcutaneous adipose tissue deposits. Apoptosis sus-
ceptibility was lowest in abdominal deposits, while arm deposits showed consistent
expression of PPAR-γ-2 without the addition of ciglitazone (a TZD). Although the
addition of TZDs can cause more extensive differentiation and lipid accumulation
in subcutaneous compared to visceral adipose depositions, the expression of PPAR-γ
was not found to be different between the different sites (Schipper et al. 2008 ).
The yield and growth characteristics of ASCs isolated from different donor sites
were evaluated by Oedayrajsingh-Varma ( 2006 ). No signifi cant difference in terms
of the yield or viability of ASCs obtained from the abdomen, hip, or thigh donor
areas was observed (Oedayrajsingh-Varma et al. 2006 ). In contrast, Jurgens and co-
workers ( 2008 ) found that the yield of ASCs from the stromal vascular fraction
(SVF) is dependent on the specifi c tissue-harvesting site. The abdominal area
yielded signifi cantly more ASCs when compared to the hip and thigh regions,
although no difference was found in the total number of nucleated cells per volume
or the ASC proliferation and differentiation capacity. When cultured, ASCs from
both regions displayed homogeneous cell populations with similar growth kinetics
and phenotype (Jurgens et al. 2008 ). Hauner and Entenmann ( 1991 ) also observed
differences in the adipogenic differentiation potential between SVF cells harvested
from abdominal and femoral adipose tissue (Hauner and Entenmann 1991 ).
Recently it was confi rmed by Iyyanki and co-workers ( 2015 ) that the SVF and
ASC yield from the abdominal area is signifi cantly higher than from the axilla and
fl ank areas (Iyyanki et al 2015 ). Taranto and co-workers ( 2015 ) explored abdominal
adipose tissue further by comparing the stromal tissue compound yield, stemness,
and multipotency of cells isolated from the superfi cial and deep adipose abdominal
layers. They demonstrated that ASCs from the superfi cial adipose tissue layer dis-
played increased SVF cell yield, increase surface expression of CD105, multipo-
tency (POU5F1, vascular endothelial growth factor (VEGF-A)) gene expression,
and tri-lineage differentiation capacity, as well as stemness (Nanog and Sox2) gene
expression (Taranto et al. 2015 ).
Identifying variation in ASCs isolated from different anatomical sites could help
to identify an ASC population better suited for specifi c structural and functional
requirements in tissue engineering (Rinkinen et al. 2015 ). These fi ndings highlight
the importance of the specifi c anatomical location as a source of ASCs.
F.A. van Vollenstee et al.