Stem cell antigen/Ly6a protects against bladder fibrosis in mice.

We have defined a population of stem cell antigen (Sca)-1+/CD34+/lin- mesenchymal stem cells in the mouse urinary bladder. These cells are reduced after partial bladder outlet obstruction (PO). To test the role of Sca-1 expressed by these cells, we analyzed bladders from Sca-1 knockout (KO) mice in both uninjured male mice and male mice subjected to PO. We found that loss of Sca-1 alone had little effect on bladder development or function but reduced the total number of mesenchymal stem cells by 30%. After PO, bladders from Sca-1-null KO male mice were larger, with more collagen and less muscle, than obstructed wild-type mice. Steady-state levels of caldesmon were significantly reduced and levels of fibroblast-specific protein 1 were significantly increased in Sca-1 KO mice compared with wild-type mice after PO. In investigating the effects of PO on cell proliferation, we found that loss of Sca-1 changed the timing of cell division in CD34+/lin-, collagen-producing, and smooth muscle cells. PO in combination with loss of Sca-1 drastically reduced the ability of CD34+/lin- cells to form colonies in vitro. Our findings therefore support the hypothesis that Sca-1 protects the bladder from fibrotic remodeling after obstruction, in part by influencing the proliferation of cells responding to the injury.

Sequential intravesical gemcitabine and docetaxel for treatment-naïve and previously treated intermediate-risk nonmuscle invasive bladder cancer.

INTRODUCTION: Adjuvant intravesical therapy is recommended for patients with intermediate-risk NMIBC. While intravesical gemcitabine-docetaxel (Gem/Doce) has demonstrated favorable outcomes for high-risk NMIBC, its utility in the intermediate-risk setting is not well described. We report outcomes of Gem/Doce as an adjuvant treatment for intermediate-risk NMIBC. METHODS: We retrospectively identified patients with intermediate-risk NMIBC by AUA criteria treated with Gem/Doce following TURBT between 2012 and 2022. Patients received weekly sequential intravesical instillations of 1 g gemcitabine and 37.5 mg docetaxel for 6 weeks. Monthly maintenance of 2 years was initiated if disease-free at first surveillance. The primary outcome was recurrence-free survival (RFS), assessed using the Kaplan-Meier method. RESULTS: The cohort included 77 patients with median follow-up of 26 (IQR 14-50) months. Prior to induction, 67 (87%) patients presented with Ta low-grade (LG) lesions, 3 (3.9%) with Ta high-grade (HG), 5 (6.5%) with TaLG plus focal TaHG, and 2 (2.6%) with T1LG. Thirty-three (43%) patients received previous intravesical therapy including BCG (23), mitomycin (13), and docetaxel monotherapy (12). The 2-year RFS was 71% among all patients. Treatment-naïve patients had superior RFS compared to previously treated patients (P = 0.04); 2-year estimates were 79% and 64%, respectively. Twenty-nine (38%) patients experienced adverse events; all were Grade 1 to 2 except 1 (1.3%) Grade 3 (acute oxygen desaturation). Three (3.9%) patients did not tolerate a full induction course. CONCLUSIONS: In this retrospective review of a heterogenous population of patients with intermediate-risk NMIBC, Gem/Doce was an effective and well-tolerated adjuvant therapy. Further prospective evaluation in this setting is needed.