Therapeutic potential of muscle growth promoters in a stress urinary incontinence model
AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY
Authors: Yang, Jun; Balog, Brian; Deng, Kangli; Hanzlicek, Brett; Rietsch, Anna; Kuang, Mei; Hatakeyama, Shinji; Lach-Trifilieff, Estelle; Zhu, Hui; Damaser, Margot S.
Abstract
Weakness of urinary sphincter and pelvic floor muscles can cause insufficient urethral closure and lead to stress urinary incontinence. Bimagrumab is a novel myostatin inhibitor that blocks activin type II receptors. inducing skeletal muscle hypertrophy and attenuating muscle weakness. beta(2)-Adrenergic agonists, such as 5-hydroxybenzothiazolone derivative (5-110B) and clenbuterol, can enhance muscle growth. We hypothesized that promoting muscle growth would increase leak point pressure (LPP) by facilitating muscle recovery in a dual-injury (DI) stress urinary incontinence model. Rats underwent pudendal nerve crush (PNC) followed by vaginal distension (VD). One week after injury, each rat began subcutaneous (0.3 mL/rat) treatment daily in a blinded fashion with either bimagrumab (DI + Bim), clenbuterol (DI + Clen), 5-HOB (DI + 5-HOB), or PBS (DI + PBS). Sham-injured rats underwent sham PNC + VD and received PBS (sham + PBS). After 2 wk of treatment, rats were anesthetized for LPP and external urethral sphincter electromyography recordings. Hindlimb skeletal muscles and pelvic floor muscles were dissected and stained. At the end of 2 wk of treatment, all three treatment groups had a significant increase in body weight and individual muscle weight compared with both sham-treated and sham-injured rats. LPP in DI + Bim rats was significantly higher than LPP of DI + PBS and DI + Clen rats. There were more consistent urethral striated muscle fibers, elastin fibers in the urethra, and pelvic muscle recovery in DI + Bim rats compared with DI + PBS rats. In conclusion, bimagrumab was the most effective for increasing urethral pressure and continence by promoting injured external urethral sphincter and pelvic floor muscle recovery.
Clenbuterol Plus Granulocyte Colony-Stimulating Factor Regulates Stem/Progenitor Cell Mobilization and Exerts Beneficial Effect by Increasing Neovascularization in Rats With Heart Failure
JOURNAL OF CARDIAC FAILURE
Authors: Tanaka, Toshikazu D.; Lancaster, Jordan J.; Juneman, Elizabeth; Bahl, Joseph J.; Goldman, Steven
Abstract
Background: Treatment of beta(2)-adrenergic receptor agonists with myeloid cytokines, such as granulocyte colony-stimulating factor (G-CSF) has been reported to enhance stem/progenitor cell mobilization and proliferation in ischemic myocardium. However, whether the combination therapy of G-CSF and clenbuterol (Clen) contributes to improved left ventricular (LV) function remains uncertain. We investigated whether this combination therapy induced bone marrow-derived stem/progenitor cell mobilization, neovascularization, and altered LV function after acute myocardial infarction (MI). Methods and Results: Following MI, rats were treated with single Clen, high-dose Clen, and G-CSF + Clen. We evaluated LV function and remodeling with the use of echocardiography in addition to hemodynamics 3 weeks after MI. Treatment with G-CSF + Clen increased (P < .05), compared with no treatment, LV ejection fraction 46 +/- 3% vs 34 +/- 2%, LV dP/dt 5,789 +/- 394 mm Hg vs 4,503 +/- 283 mm Hg, and the percentage of circulating CD34+ cells, appearing to correlate with improvements in LV function. Conclusions: Combination therapy improved LV function 3 weeks after MI, suggesting that G-CSF + Clen might augment stem/progenitor cell migration, contributing to tissue healing. These data raise the possibility that enhancing endogenous bone marrow-derived stem/progenitor cell mobilization may be a new treatment for ischemic heart failure after MI.