Page 6 - Sexual Health Treatments

Adipose-Derived Stem Cells and Erectile Dysfunction 325

that BMSCs alone or transduced with eNOS were damaged erectile function in an animal model.
able to reverse age-associated ED. Song et al. [44] Several possible mechanisms underlying the treat-
showed that magnetic resonance could be used to ment were proposed. First, the cell-based mecha-
noninvasively evaluate human BMSC in corpus nism indicated that ADSCs differentiated into
cavernous of rats and rabbits. Also, Song et al. local functional cells, including SMCs and endot-
showed that immortalized human BMSC (by helium. Second, the growth factor-based mecha-
v-myc transfection) transplanted into rat corpus nism indicated that the growth factors secreted
cavernosum could differentiate into endothelial from the ADSCs underwent one of the following
cells and SMCs. situations: (i) recruit local stem cells and activity to
Also, the skeletal muscle-derived stem cells differentiation; (ii) attract the systemic stem cells
(MDSCs) have been converted into SMCs both in to the penis by homing effect; (iii) IGF-1 promotes
vitro and in vivo, and were shown to recover erec- local functional cell growth; (iv) the neurotrophic
tile function in the aged rats [45]. Although these effect to promote nerve regeneration, which needs
results suggest exogenous stem cell implantation to be confirmed by further studies.
and/or endogenous stem cell modulation might be
a viable therapeutic approach for age-related ED, Perspectives
the application of MDSCs obtained from muscle is
limited due to the source and number of this kind The ADSCs are regarded as candidates for the
of stem cell. treatment of ED due to many factors. These stem
Song et al. investigated the feasibility of apply- cells can easily be obtained in large quantities
ing neural crest stem cells (NCSCs) to repair under local anesthesia, they possess the potential
injury in the penile cavernosum and found that to undergo long-term proliferation, self-renewal,
these stem cells differentiated into either endothe- and multipotent differentiation, and they can serve
lial cells or SMCs, as shown by their expression of as a vehicle for release of neurotrophins, such as
cell type-specific markers. However, the function nerve growth factor, to repair damages due to dia-
of these differentiated cells had not been explored betes or pelvic surgery.
in their experiment [46]. In addition to using ADSCs for treatment of
ED, there are several other kinds of andrology
Application of ADSCs disorders that can benefit from stem cell therapy,
Garcia et al. isolated human ADSCs from a lipo- including the reconstruction of penile tissue,
suction procedure, and administered according to enlargement of the penis, and strengthening of the
a strict protocol that involves infusion of the cells vaginal muscle. There is also the potential appli-
into the target lesion along with fibrin glue in a cation for use of ADSCs in steroid hormone
human phase IIb clinical study [47]. The clinical therapy.
results satisfied the effectiveness to induce healing Corresponding Author: Guiting Lin, MD, PhD,
in a complex of perianal fistulas, though the under- Department of Urology, University of California, San
ling mechanism needs to be further explored. Francisco, CA 94143-0738, USA. Tel: 415-476-3801;
Also, human ADSCs have been successfully Fax: 415-476-3803; E-mail: glin@urology.ucsf.edu
applied to reverse urethral incontinence in an
animal model in 2005 [48]. The ADSCs were also Conflict of Interest: None declared.
isolated from human lipoaspirate, labeled with a
fluorescent tag and suspended in Hanks’ balanced References
salt solution. The multiple animal models, includ- 1 Thomson JA, Itskovitz-Eldor J, Shapiro SS,
ing eight Rnu athymic rats and six severe combined Waknitz MA, Swiergiel JJ, Marshall VS, Jones JM.
immunodeficient (SCID) mice underwent laparo- Embryonic stem cell lines derived from human blas-
tomy and injection of ADSCs into the bladder and tocysts. Science 1998;282:1145–7.
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weeks in the lower urinary tract and differentiated Adipose-derived stromal cells—Their utility and
into SMCs, which implies that ADSCs may provide potential in bone formation. Int J Obes Relat Metab
Disord 2000;24(4 suppl):S41–4.
a feasible and cost-effective cell source for urinary 3 Yu J, Vodyanik MA, Smuga-Otto K, Antosiewicz-
tract reconstruction. The major defect of this study Bourget J, Frane JL, Tian S, Nie J, Jonsdottir GA,
is the lack of functional studies on those animals. Ruotti V, Stewart R, Slukvin II, Thomson JA.
Recently, a pilot experiment has been con- Induced pluripotent stem cell lines derived from
ducted [15] and found that ADSCs improved the human somatic cells. Science 2007;318:1917–20.

J Sex Med 2009;6(suppl 3):320–327