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doublings at higher seeding densities were not statistically signifi cant. The older
patients however had a smaller regression coeffi cient than younger patients, demon-
strating less change in population doublings with increasing seeding densities
(Fossett et al. 2012 ). Fossett and colleagues ( 2012 ) further demonstrated that syno-
vial fat pad- derived ASCs plated at a density of 50 cells/cm^2 showed a 980-fold
increase in ASC proliferation for females and a 367-fold increase for male patients
over a period of 21 days. In addition, the investigated cell surface markers demon-
strated little difference between genders except for STRO-1 which was expressing
at higher levels in female relative to male patients. Based on the fact that estrogens
upregulate receptor expression on embryonic stem cells and the previously sug-
gested notion that androgens have inhibitory effects and estrogens a stimulatory
effect on MSCs, the possibility was suggested that gender may account for the vari-
ability observed (Fossett et al. 2012 ; Ray et al. 2008 ).
10.2.3 Harvesting Techniques
The ideal source of stem cells used for regenerative medical applications should
(1) be easily obtainable, with minimal discomfort to the patient via a minimally
invasive procedure, (2) yield suffi cient numbers of cells for extensive cell cultur-
ing, (3) be able to differentiate along multilineage pathways in a controlled and
reproducible manner, (4) be transplantable to either autologous or allogeneic hosts
safely and effectively, and (5) be able to be manufactured in accordance with GMP
guidelines (Mizuno 2009 ). Adipose tissue-derived stromal/stem cells can be con-
sidered to fulfi ll all these criteria. With regard to harvesting, raw lipoaspirate can
easily be obtained by suction-assisted lipectomy also known as liposuction, lipo-
plasty, or simply fat suctioning. This method in comparison to other tissue-harvest-
ing techniques has minimal ethical considerations and limited pain and discomfort
to the patient and demonstrates an increased cellular yield and viability (Dominici
et al. 2006 ).
10.2.3.1 Liposuction Versus Biopsy/Resection
Oedayrajsingh-Varma and co-workers ( 2006 ) evaluated the yield and growth char-
acteristics of isolated ASCs using different harvesting techniques. Their fi ndings
demonstrated that adipose tissue harvested by both resection (biopsy) and wet/
tumescent liposuction (described below) techniques provided high yields of rapidly
growing ASCs, whereas adipose tissue obtained by ultrasound-assisted liposuction
provided a low yield of ASCs exhibiting a low proliferative capacity. More than
80 % of the cells exhibited an ASC phenotype, irrespective of the operative proce-
dure performed (Oedayrajsingh-Varma et al. 2006 ).
A comparative study evaluating the viability of ASCs from excised versus
aspirated adipose tissue showed a signifi cant loss in viability within the excised
F.A. van Vollenstee et al.