Page 3 - Sexual Health Treatments

322 Lin et al.

Actually, several lines of evidence suggest that
ADSCs are vascular precursor cells. Many studies
have shown that SVF contains progenitor cells
that are able to differentiate into endothelial cells
and participate in blood vessel formation. Also, a
recent study demonstrated that SVF cells express-
ing both pericyte and mesenchymal markers reside
in a periendothelial location and stabilize endot-
helial networks [22]. Another recent study showed
that ADSCs transplanted into ischemic cortex
preferentially migrate toward microvessels where
they differentiate into vascular SMCs [2]. By
extensive histology, flow cytometric assay, it was
shown that smooth muscle actin (SMA) and CD31
localized within smooth muscle and endothelial
cells, respectively, in all blood vessels examined.
CD34 localized to both the intima (endothelium) Figure 1 A hypothetical scheme of the adipose-derived
and adventitia, neither of which expressed SMA. stem cells niche consists of four components: cap cells-
The niche marker Wnt5a was confined exclusively endothelial cells, basal membrane, supporting cells-
to the vascular wall, within mural SMCs. Surpris- pericytes, and stem cells.
ingly, the widely accepted MSC marker STRO-1
was expressed exclusively in the endothelium of
capillaries and arterioles but not in the endothe- metric sorting, these ADSCs have been shown to
lium of arteries. The ESC marker SSEA1 localized share many of the same cellular markers with the
to a pericytic location in capillaries and in certain BMSCs, such as CD9, CD10, CD13, CD29,
SMCs of arterioles. Cells expressing the ESC CD117, CD34, CD90, CD105, and STRO-1
markers telomerase and OCT4 were rare and (Table 1).
observed only in capillaries. Tang et al. also The ADSCs display multipotency by retaining
identified the progenitor cells in WAT within the ability to differentiate into cell types of differ-
the adipose vasculature [18]. Notably, Rodeheffer ent lineages, including neurogenic, chondrogenic,
et al. reported a similar result by employing a osteogenic, adipogenic, myogenic, cardiomyo-
variety of approaches [17]. Based on these findings genic, vascular/endothelial, hepatic, and pan-
and evidence gathered from the existing literature, creatic differentiation (Figure 2). In the current
it has been proposed that ADSCs are vascular pre- review, we mainly focus on neurogenic differentia-
cursor (stem) cells at various stages of differentia- tion, smooth muscle differentiation, and endothe-
tion [8]. These studies serve to solidify the idea lial differentiation, which encompass the dominant
that ADSCs are in fact derived from the adipose differentiation pathways for functional cells
vasculature where the stem cells reside in a located within the penile erectile tissue.
microenvironment that has been hypothetically
named as the ADSC niche (Figure 1). Neuron Differentiation
It has been shown that ADSCs can be induced by
isobutylmethylxanthine (IBMX) to differentiate
The Isolation and Differentiation of ADSCs In Vitro
into neuron-like cells in vitro [5,10,25]. This
In recent years, the ADSCs as a new source of IBMX-induced neuronal differentiation was medi-
ASCs have been extensively explored [14,23,24]. ated by the IGF-I signaling pathway. The signifi-
The ADSCs can be developed with a series of steps cance of these studies is that ADSCs have the
including isolation, sorting, culture, differentia- potential to treat degenerative neurological dis-
tion, and application. Firstly, the adipose tissue was eases including neurogenic erectile dysfunction
digested with collagenase type IA, sorted by a cell (ED), which frequently occurs in patients who
strainer and specific stem cell markers [4]. These have undergone pelvic floor surgeries or radiation.
cells can be cultured in regular culture medium Due to the fact that future clinical applica-
and can be induced into different cell types using tions will likely use these ASCs in an autologous
induction medium. Afterward, the cells can be fashion, ADSCs could be induced to differentiate
used for many different purposes. Using flow cyto- into neuron-like cells which expressed neuronal

J Sex Med 2009;6(suppl 3):320–327