205cultures, isolated both at 1 h and at 24 h. In addition, these results clearly
demonstrated that adipose tissue extraction by suction does not damage the SVF. The
group went further and suggested that liposuction is the better method for harvest-
ing ASCs (von Heimburg et al. 2004 ).
A recent side-by-side comparative study of bone marrow-derived MSCs with
ASCs obtained through liposuction or from resection showed increased prolifera-
tion and differentiation capacity of ASCs obtained from liposuction, inferring that
liposuction produces a more homogenous population of stem cells than the ASCs
obtained from resection. Interestingly, although the ASCs obtained from liposuc-
tion and resection were collected from the same patient at the same donor site, dif-
ferences in gene expression profi les were observed (Gnanasegaran et al. 2014 ).
Gene expression in ASCs (liposuction) showed an endoderm propensity with the
expression of SOX17 and ISL1 (roles in beta cells) and GFAP (role in neurogene-
sis). ASCs obtained from resection demonstrated distinct gene expression tending
toward mesoderm and ectoderm lineages. ASCs obtained via resection distinctly
expressed OLIG2, which is related to oligodendrocyte formation and regulation of
ventral neuroectodermal progenitor cell fate (Gnanasegaran et al. 2014 ).
The procedure of performing liposuction has become common practice among
plastic and reconstructive surgeons. A 2014 survey indicated that 13,728,901 lipo-
suctions are performed annually by approximately 35,000 plastic surgeons world-
wide (International Survey on Aesthetic/Cosmetic Procedures Performed).
Liposuction was also scored at 14.2 % of the total surgical procedures performed
by plastic surgeons, indicating that this is one of the most common surgical proce-
dures in this fi eld ( http://www.isaps.org ). The current trends in liposuction and
other fat- removal techniques in the United States were also surveyed by the
American Society for Aesthetic Plastic Surgery (ASAPS). The number of liposuc-
tions performed in the Unites States from 1997 to 2014 has increased by 51.6 %,
and in 2014 liposuction was the most popular cosmetic surgical procedure with a
total of 342,494 procedures ( http://www.surgery.org ). Multiple factors such as
genetic, epigenetic, and behavioral factors contribute to the increasing global obe-
sity epidemic. This epidemic favors adipose tissue as a stem cell source for regen-
erative medicine, as subcutaneous adipose tissue is abundant and readily accessible
(Katz et al. 1999 ).
Adipose tissue is the richest source of stem cells in the human body, containing
100- to 1000-fold more multipotent cells per unit volume compared to the bone
marrow (Tjabringa et al. 2008 ). It was demonstrated that about 3.5 × 10^4 preadipo-
cytes can be isolated from 1 g of adipose tissue (Ersek and Salisbury 1995 ; Fournier
and Otteni 1983 ; von Heimburg et al. 2004 ). Fraser and colleagues ( 2006 ) demon-
strated that 1 g of adipose tissue yields a 500-fold greater number of ASCs than the
number of MSCs derived from 1 g of bone marrow. Liposuction can yield anywhere
from 100 ml to >3 L of lipoaspirate, which is then routinely discarded. This data
highlights one of the ideal characteristic of a stem cell source, namely, that it is eas-
ily obtainable in large quantities (Fraser et al. 2006 ).
10 Harvesting and Collection of Adipose Tissue for the Isolation...