Yoshihiro Maeda

Pharmacological effects of solifenacin on human isolated urinary bladder.

To investigate the effects of solifenacin on human detrusor smooth muscles, we evaluate the effects of solifenacin on the contractions induced by carbachol, KCl, CaCl2 and electrical field stimulation (EFS), and the EFS-induced acetylcholine release from detrusor smooth muscle strips by using the muscle bath and microdialysis technique. The effects of solifenacin were also compared with effects of other antimuscarinic agents (atropine, oxybutynin and propiverine). Pretreatment with various antimuscarinic agents caused parallel shifts to the right of the concentration-response curves to carbachol. The pA2 value of the Schild plots for solifenacin was similar to that for oxybutynin. Atropine did not inhibit the KCl- and CaCl2-induced contractions, while solifenacin, oxybutynin and propiverine significantly inhibited these contractions. EFS-induced contractions were inhibited by various antimuscarinic drugs in a concentration-dependent manner. In the presence of atropine, solifenacin tended to inhibit the residual atropine-resistant contractions induced by EFS, but it was not significant. However, oxybutynin and propiverine inhibited them under the same conditions. Although pretreatment with atropine and propiverine did not cause significant changes in EFS-induced acetylcholine release, solifenacin and oxybutynin caused significant decreases in acetylcholine release. The present results suggest that solifenacin inhibits contractions of human detrusor smooth muscles mainly by the antimuscarinic action and that the high concentration of solifenacin has Ca2+ channel antagonist action. Moreover, solifenacin may block not only postjunctional receptors, but also prejunctional receptors to modulate acetylcholine releases in cholinergic nerve endings in human detrusor smooth muscles. The findings support that muscarinic-receptor-inhibitory actions in human bladder mainly contribute to the usefulness of solifenacin as a therapeutic drug for overactive bladder.

C5aR is frequently expressed in metastatic renal cell carcinoma and plays a crucial role in cell invasion via the ERK and PI3 kinase pathways

The anaphylatoxin C5a is a chemoattractant for leukocyte migration via the C5a receptor (C5aR). We recently reported that C5aR was aberrantly expressed in a wide variety of human related cancers, while it also promotes cancer cell invasion by C5a stimulation. However, the biological significance of C5aR expression in renal cell carcinoma (RCC) has not yet been clarified. In the present study, we aimed to elucidate the biological role of C5aR in RCC progression. Clinical RCC specimens were analyzed for C5aR expression and its relationship with baseline demographic data and clinicopathological parameters was analyzed. Moreover, renal carcinoma Renca cells stably expressing C5aR were generated and used to assess the effects of C5a-C5aR axis activation on various cellular phenomena in culture. Immunohistochemistry revealed that 96.7% of the metastatic RCCs (mRCCs) showed C5aR expression, whereas only 50.5% of the non-metastatic RCCs expressed C5aR (P<0.001). Although C5a stimulation did not significantly alter anoikis of C5aR‑expressing Renca cells, C5a elicited cell morphological change and scattering of those cells accompanied with dynamic actin rearrangement, which was not observed in the Renca cells harboring the empty vector only. Moreover, C5a triggered ERK and PI3K‑dependent invasion of the C5aR-expressing renal carcinoma cells. These results are consistent with the idea that the C5a-C5aR axis plays a crucial role in renal carcinoma cell invasion, which may be one of the key steps for RCC metastasis. The present study provides proof‑of‑concept that the C5a-C5aR axis may be a useful therapeutic target for preventing RCC progression.

Change in acetylcholine release from rat bladder with partial outlet obstruction

To investigate changes in acetylcholine release from the bladder of rats with partial bladder outlet obstruction (BOO), as partial BOO leads to hypertrophy and an alteration in the contractions of the detrusor smooth muscle, and acetylcholine plays an important role in urinary bladder contractions but there is little available information on acetylcholine release after BOO.

Pharmacological effects of propiverine and its active metabolite, M-1, on isolated human urinary bladder smooth muscle, and on bladder contraction in rats.

Objective:  To investigate the effects of M‐1, a major active metabolite of propiverine on the bladder.

Attenuation of Non‐neuronal Adenosin Triphosphate Release from Human Bladder Mucosa by Antimuscarinic Agents

Objectives: To clarify the contribution of mucosal muscarinic receptors to bladder function, we investigated the effects of various antimuscarinic drugs on stretch‐induced non‐neuronal adenosin triphosphate (ATP) release in human bladder.

Sorafenib enhances the antitumor effects of anti-CTLA-4 antibody in a murine cancer model by inhibiting myeloid-derived suppressor cells.

This antitumor effect of sorafenib is considered to be dependent not only on its direct cytotoxicity to cancer cells but also due to the inhibition of myeloid-derived suppressor cells (MDSCs). Recently, a novel antibody against cytotoxic T-lymphocyte antigen 4 (CTLA-4), which activates lymphocytes, is currently in clinical applications. The aim of the present study was to investigate the synergistic antitumor effects of anti-CTLA-4 antibody (Ab) and sorafenib in a murine cancer model. RENCA cells were subcutaneously inoculated into mice, which were randomly divided into 4 treatment groups: sorafenib plus anti-CTLA-4 Ab, sorafenib plus control Ab, vehicle plus anti-CTLA-4 Ab, and vehicle plus control Ab. Single therapy using anti-CTLA-4 Ab suppressed tumor growth, but no difference was noted when compared with the single therapy group using sorafenib. Notably, the greatest decrease in tumor size was noted with sorafenib plus anti-CTLA-4 Ab (combination therapy), and the highest rate of tumor rejection was observed in the combination therapy group. The number of infiltrating CD4- or CD8-positive lymphocytes was strongly increased in the combination therapy group. These in vivo data indicate that sorafenib increased the immunostimulatory effect of anti-CTLA-4 Ab even when sorafenib was used at a low dose. An in vitro study using MDSCs and CD8(+) T cells showed that the inhibitory effect of MDSCs on CD8(+) T cells was significantly abrogated by the combined use of sorafenib and anti-CTLA-4 Ab. Sorafenib suppressed the expression of immunosuppressive factors in MDSCs. These data indicate that combination therapy of sorafenib and anti-CTLA-4 Ab may be effective in advanced kidney cancer patients.

Severe bleeding tendency caused by a rare complication of excessive fibrinolysis with disseminated intravascular coagulation in a 51-year-old Japanese man with prostate cancer: a case report

IntroductionDisseminated intravascular coagulation causes thrombotic tendency leading to multiple organ failure and occurs in a wide variety of diseases including malignancy. Disseminated intravascular coagulation is a latent complication in people with prostate cancer.Case presentationA 51-year-old Japanese man with advanced castration-resistant prostate cancer was admitted to our hospital because of extensive purpura and severe anemia. Prolonged plasma coagulation time, hypofibrinogenemia and normal platelet count suggested that a decrease in fibrinogen induced a bleeding tendency causing purpura. However, elevated plasma levels of thrombin-antithrombin complex, fibrin and/or fibrinogen degradation products and D-dimers, with positive fibrin monomer test, manifested disseminated intravascular coagulation and subsequent fibrinolysis. Plasma levels of thrombin-antithrombin complex, fibrin and/or fibrinogen degradation products and D-dimers decreased after administration of low-molecular-weight heparin. However, low fibrinogen and α2-antiplasmin levels were not improved and plasmin-antiplasmin complex did not decrease, which revealed excessive fibrinolysis complicated with disseminated intravascular coagulation. We suspected that prostate cancer cell-derived urokinase-type plasminogen activator caused excessive fibrinolysis. Administration of tranexamic acid for fibrinogenolysis was added together with high-dose anti-androgen therapy (fosfestrol) for prostate cancer. Thereafter, prostate-specific antigen and plasmin-antiplasmin complex decreased, followed by normalized fibrinogen and α2-antiplasmin levels, and the patient eventually recovered from the bleeding tendency. Immunohistochemical staining of the biopsied prostate tissue exhibited that the prostate cancer cells produced tissue factor, the coagulation initiator, and urokinase-type plasminogen activator.ConclusionThis patient with rare complications of disseminated intravascular coagulation and excessive fibrinolysis is a warning case of potential coagulation disorder onset in patients with prostate cancer. We propose that combined administration of tranexamic acid and low-molecular-weight heparin together with high-dose anti-androgen therapy is a useful therapeutic option for patients with this complicated coagulation disorder.