Presentation Authors: Istvan Kovanecz, Robert A Gelfand, Torrance, CA, Guiting Lin, San Francisco, CA, Sheila Sharifzad, Randy Ricks, Tom Lue, Nestor Gonzalez-Cadavid*, Torrance, CA
Introduction: Female stress urinary incontinence (FSUI) is prevalent in women with type 2 diabetes/obesity (T2D/O), and treatment is not optimal. Stem cells (SC) may repair endogenously the damaged bladder urethral myosphincter (BUM), but have poor efficacy in SC therapy, usually as autografts. In the male Zucker fatty (ZF) rat model of T2D/O with erectile dysfunction, the repair capacity of muscle derived SC (MDSC) is impaired in aging by a long-term exposure to dyslipidemic milieu, that triggers a noxious phenotype and abnormal global transcriptional signatures (GTS) of genes and microRNAs (miRs). This is mimicked in vitro by treatment of MDSC with dyslipidemic serum or lipid factors. In order to predict whether SC damage occurs in T2D/O-associated FSUI, impairing their endogenous and SC therapy repair capacity, we studied whether: 1) the dyslipidemic serum from aged female ZF rats (ZF-S) damages in vitro the SC from young normoglycemic ZF rats (ZF-SC), in comparison with serum from control Zucker lean rats (ZL-S), and 2) the ZF-SC are more impaired than the SC from ZL rats (ZL-SC).
Methods: ZF-SC and ZL-SC from pelvic muscles were incubated in DMEM/ serum, with added either dyslipidemic ZF-S or normolipidemic ZL-S (1-5%), or no addition (NA). At 4 days: a) quantitative histochemistry measured fat deposits (Oil red O), apoptosis (Tunel), and scratch wound repair (HE), b) western blots measured proliferation (PCNA), smooth muscle (calponin 1) and skeletal myofiber (MHC-II) differentiation, and a muscle inhibitor/pro-lipofibrotic factor (myostatin), and c) miR-GTS were determined.
Results: ZF-S compared with NA increased similarly fat infiltration and apoptosis in the ZF-SC and ZL-SC, reduced % gap closure (11- vs 3-fold), and SC proliferation and differentiation, but increased myostatin. ZL-S was nearly ineffective. Many individual miRs in untreated ZF-SC and ZL-SC compared with male MDSC, varied >2 fold (e.g., lower 100-5p, 99a-5p; higher 143-3p, 221-5p), as well as between themselves. Treatment with ZF-S, but not ZL-S, reduced miRs decreased in MDSC by the T2D/O milieu, related to myostatin inhibition (e.g., 21-5p, 199a-5p) or unrelated (e.g., 99b-5p, 10b-5p).
Conclusions: The dyslipidemic ZF-S damages both SC in vitro, and up-regulates myostatin, in agreement with miR-GTS changes, thus resembling the male ZF rat model. This predicts noxious effects in vivo of the T2D/O milieu impairing endogenous SC tissue repair and autograft SC therapy for FSUI.
Source of Funding: NIH R01DK #105092-03