Pharmacological effects of TAK-828F: an orally available RORγt inverse agonist, in mouse colitis model and human blood cells of inflammatory bowel disease.

OBJECTIVE AND DESIGN: To evaluate the potency of RORγt blockade for treatment of Inflammatory Bowel Disease (IBD), the efficacy of TAK-828F, a novel RORγt inverse agonist, in anti-TNF-α mAb non-responsive mouse colitis model and effect of TAK-828F on IL-17 production in peripheral mononuclear blood cells (PBMCs) of anti-TNF-α naive and treatment-failure patients of IBD was investigated. METHODS AND RESULTS: The colitis model showed Th17-dependent pathogenicity and response to anti-IL-12/23p40 monoclonal antibody (mAb), but no response to anti-TNF-α mAb. In the model, TAK-828F, at oral dosages of 1 and 3 mg/kg, inhibited progression of colitis and reduced the immune reaction that characterize Th17 cells. Anti-IL-17A mAb showed neither efficacy nor change in the T cell population and colonic gene expression in the model. In the normal mouse, a 4-week treatment of TAK-828F at 30 mg/kg did not severely reduce lymphocyte cell counts in peripheral and intestinal mucosa, which was observed in RORγ-/- mice. TAK-828F strongly inhibited IL-17 gene expression with IC50 values from 21.4 to 34.4 nmol/L in PBMCs from anti-TNF mAb naive and treatment-failure patients of IBD. CONCLUSIONS: These results indicate that RORγt blockade would provide an effective approach for treating refractory patients with IBD by blocking IL-23/Th17 pathway.

Impaired diffuse noxious inhibitory controls in specific alternation of rhythm in temperature-stressed rats.

Fibromyalgia is characterized by chronic widespread musculoskeletal pain. A hypofunction in descending pain inhibitory systems is considered to be involved in the chronic pain of fibromyalgia. We examined functional changes in descending pain inhibitory systems in rats with specific alternation of rhythm in temperature (SART) stress, by measuring the strength of diffuse noxious inhibitory controls (DNIC). Hindpaw withdrawal thresholds to mechanical von Frey filament or fiber-specific electrical stimuli by the Neurometer system were used to measure the pain response. To induce DNIC, capsaicin was injected into the intraplantar of the forepaw. SART-stressed rats were established by exposure to repeated cold stress for 4 days. In the control rats, heterotopic intraplantar capsaicin injection increased withdrawal threshold, indicative of analgesia by DNIC. The strength of DNIC was reduced by naloxone (µ-opioid receptor antagonist, intraperitoneally and intracerebroventricularly), yohimbine (α2-adrenoceptor antagonist, intrathecally), and WAY-100635 (5-HT1A receptor antagonist, intrathecally) in the von Frey test. In SART-stressed rats, capsaicin injection did not increase withdrawal threshold in the von Frey test, indicating deficits in DNIC. In the Neurometer test, deficient DNIC in SART-stressed rats were observed only for Aδ- and C-fibers, but not Aß-fibers stimulation. Analgesic effect of intracerebroventricular morphine was markedly reduced in SART-stressed rats compared with the control rats. Taken together, in SART-stressed rats, capsaicin-induced DNIC were deficient, and a hypofunction of opioid-mediated central pain modulation system may cause the DNIC deficit.

Bidirectional regulation of human colonic smooth muscle contractility by tachykinin NK(2) receptors.

In this study, we attempted to clarify the mechanism of tachykinin-induced motor response in isolated smooth muscle preparations of the human colon. Fresh specimens of normal colon were obtained from patients suffering from colonic cancer. Using mucosa-free smooth muscle strips, smooth muscle tension with circular direction was monitored isometrically. Substance P (SP), neurokinin A (NKA), and neurokinin B (NKB) produced marked contraction. All of these contractions were inhibited by saredutant, a selective NK(2)-R antagonist, but not by CP122721, a selective NK(1)-R antagonist or talnetant, a selective NK(3)-R antagonist. ßAla(8)-NKA(4-10) induced concentration-dependent contraction similar to NKA, but Sar(9)-Met(11)-SP and Met-Phe(7)-NKB did not cause marked contraction. Colonic contraction induced by ßAla(8)-NKA(4-10) was completely blocked by saredutant, but not by atropine. Tetrodotoxin or N(G)-nitro-L-arginine methyl ester pretreatment significantly enhanced ßAla(8)-NKA(4-10)-induced contraction. Immunohistochemical analysis showed that the NK(2)-R was expressed on the smooth muscle layers and myenteric plexus where it was also co-expressed with neuronal nitric oxide synthase in the myenteric plexus. These results suggest that the NK(2)-R is a major contributor to tachykinin-induced smooth muscle contraction in human colon and that the NK(2)-R-mediated response consists of an excitatory component via direct action on the smooth muscle and an inhibitory component possibly via nitric oxide neurons.

Cold response of the bladder in guinea pig: involvement of transient receptor potential channel, TRPM8.

OBJECTIVES: To address the physiologic role of TRPM8, one of the transient receptor potential channels, we investigated the bladder cooling reflex and the effect of menthol on it in the guinea pig. METHODS: Single cystometry in female Hartley guinea pigs was performed with high-speed infusion (60 mL/hr) under urethane anesthesia (1 g/kg intraperitoneally). The volume threshold for micturition (VT) and micturition pressure were determined. The distribution of TRPM8 in the S1 dorsal root ganglion (DRG) was also examined by immunostaining. RESULTS: Intravesical infusion of saline containing menthol (0.6 mM) at 38 degrees C markedly decreased the VT and increased micturition pressure. Although cold saline itself (4 degrees C) had little effect on VT or micturition pressure, the VT was significantly decreased in a temperature-dependent manner when the bladder was pretreated with menthol. This decrease in the VT was not observed in animals that received hexamethonium pretreatment (10 mg/kg intravenously), which blocks the spinal reflex, or capsaicin (1 mM intravesically), which causes deafferentation of capsaicin-sensitive C-fiber afferent. Immunohistochemical analysis revealed that TRPM8 is expressed in small-diameter neurons in guinea pig S1 dorsal root ganglions. CONCLUSIONS: The results of our study showed that the bladder cooling reflex is observed in guinea pigs if the animals were pretreated with menthol. This reflex was sensitive to ganglion blockade or capsaicin-sensitive C-fiber deafferentation and might be mediated by C-fiber activation through TRPM8.

Effects of NSAIDs on bladder function in normal and cystitis rats: a comparison study of aspirin, indomethacin, and ketoprofen.

To clarify the potential usefulness of non-steroidal anti-inflammatory drugs, NSAIDs, for patients with overactive bladder, we examined the effect of NSAIDs on urodynamic parameters in normal and cystitis rats and compared their ulcerogenic activity in the gastrointestinal mucosa. Cystometry was performed after administration of the conventional NSAIDs, aspirin, indomethacin, or ketoprofen. Prostaglandin levels were measured in the bladder of cystitis rats pretreated with NSAIDs. Furthermore, the ulcerogenic responses were examined. NSAIDs increased bladder capacity without any effect on micturition pressure in normal rats in the following rank order of potency: ketoprofen > or = indomethacin > or = aspirin. In cystitis rats, bladder capacity was increased and micturition frequency was decreased. The levels of prostaglandin were significantly increased in cystitis rats. All NSAIDs inhibited the increment of prostaglandin levels at doses equal to that effective in the improvement of bladder functions. When administered intraduodenally, both ketoprofen and indomethacin induced lesions in the gastrointestinal mucosa. However, aspirin had no significant effect. We demonstrate that NSAIDs are effective in animal models of disease, most likely by suppressing by prostaglandin synthesis. Since aspirin, in contrast to ketoprofen or indomethacin, did not cause any gastrointestinal lesions, aspirin might be the NSAIDs treatment of choice for overactive bladder.

Mechanism of action by which aspirin alleviates detrusor hyperactivity in rats.

We examined the effect of aspirin on urodynamic parameters in normal and cyclophosphamide-induced cystitic rats and compared them in rats with or without sensory denervation. Cystometry was performed under urethane anesthesia; and volume threshold for micturition (VT), micturition frequency (MF), micturition pressure (MP), and micturition volume (MV) were determined. Cystitis was induced by pretreatment with cyclophosphamide and sensory denervation was performed by pretreating animals with a large dose of capsaicin. PGE(2) and 6-keto-PGF(1alpha) contents in the bladder were determined by ELISA. Sensory intact, cystitic rats showed decrement of VT and increment of MF. Aspirin increased VT and decreased MF in the cystitic condition. Both PGE(2) and 6-keto-PGF(1alpha) contents in the bladder were significantly increased in cystitic rats, but such increases were completely inhibited by aspirin. In sensory denervated rats, aspirin showed a marginal tendency of increment of VT. Cystitic rats showed overflow micturition in the sensory denervated condition, but VT was the same as that of normal rats. Furthermore, following capsaicin pretreatment, aspirin had no effect on the cystometrogram in cystitic rats. From these findings, it is concluded that suppression of sensory C-fiber via inhibition of PGs synthesis in the bladder is involved in the pharmacological action of aspirin in the detrusor hyperactivity.