AB08. Stem cell therapy in urology

Stem cells (SCs) are classified into embryonic and adult types; the latter is further divided into several subtypes including mesenchymal stem cells (MSCs), which are the most extensively studied adult SCs in the field of regenerative medicine. In urology the most frequently used MSCs are derived from the bone marrow, skeletal muscle, and adipose tissue. Due to its abundant tissue source and ease of isolation, adipose tissue-derived MSC (ADSC) is gaining wider acceptance as the most promising therapeutic cell type. Regardless of their tissue origin, MSCs have been shown to locate near or within blood vessels. In adipose tissue we demonstrated their localization in the capillaries and in the adventitia of larger blood vessels, and this has been independently confirmed by all subsequent studies. Thus, in a recent review article we proposed that MSCs are vascular stem cells, and this helps explain why MSCs exist in not only the bone marrow but also other adult tissues. Although MSCs have been shown to possess multi-lineage differentiation potential, the evidence is mostly in vitro. In a recent review article we discussed in detail why current in vivo evidence is unconvincing. Furthermore, in a recent book chapter we discussed that, instead of cellular differentiation, paracrine action is the principal mechanism through which MSCs exert therapeutic effects. MSC therapy for the kidney has been demonstrated in both acute and chronic renal failure animal models. The mechanism is generally trophic and anti-inflammatory while cell differentiation or engraftment is rarely detected. In 3 recent clinical trials MSC administration has been shown to improve kidney transplantation. For the ureter, both BMSC and ADSC have been tested for the construction of tissue grafts. For the bladder, MSCs have been investigated for the construction of tissue grafts and for the treatment of bladder dysfunction. In regard to the urethra, which is the most extensively investigated urological tissue in terms of SC therapy, we have recently summarized and discussed all published studies on SC therapy for stress urinary incontinence. In regard to the penis, which is the second most investigated urological organ in terms of SC therapy, we have also recently summarized and discussed all published studies on SC therapy for erectile dysfunction. Papers that are published more recently will be updated in this talk.