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Abstract Boron neutron capture therapy (BNCT) is a high-LET particle radiotherapy clinically tested for treating malignant gliomas. Boronophenylalanine (BPA), a boron-containing phenylalanine derivative, is selectively transported into tumor cells by amino acid transporters, making it an ideal agent for BNCT. In this study, we investigated whether the amino acid 5-aminolevulinic acid (ALA) could sensitize glioma stem cells (GSCs) to BNCT by enhancing the uptake of BPA. Using human and mouse GSC lines, pre-incubation with ALA increased the intracellular accumulation of BPA dose-dependent. We also conducted in vivo experiments by intracerebrally implanting HGG13 cells in mice and administering ALA orally 24 h before BPA administration (ALA + BPA-BNCT). The ALA preloading group increased the tumor boron concentration and improved the tumor/blood boron concentration ratio, resulting in improved survival compared to the BPA-BNCT group. Furthermore, we found that the expression of amino acid transporters was upregulated following ALA treatment both in vitro and in vivo, particularly for ATB0,+. This suggests that ALA may sensitize GSCs to BNCT by upregulating the expression of amino acid transporters, thereby enhancing the uptake of BPA and improving the effectiveness of BNCT. These findings have important implications for strategies to improve the sensitivity of malignant gliomas to BPA-BNCT.

Objective: To emphasize the importance of patients’ actual subjective satisfaction with the outcome of surgery for trigeminal neuralgia (TGN) using a standardized analysis that combines pain relief and complications. Methods: Ninety-four patients with TGN who underwent surgery and were followed up for 2–15 years (2006–2019) at Shiroyama Hospital, Osaka, Japan were enrolled. Patient subjective satisfaction was measured by evaluating the surgical results: the pain score (P) represented residual pain levels, ranging from P-0 (complete pain relief) to P-1, P-2, and P-3, wherein pain persisted in variable degrees. The complication score (C) ranged from C-0 (no complications after surgery) to C-1 and C-2 in which slight or problematic nerve dysfunction remained. The total surgical result for patient satisfaction (T) represented the summed P and C scores (T = P + C). Results: Among the 94 patients, 81 (86.2%) were categorized as having P-0. In 13 (13.8%) patients, the pain persisted with P-1, P-2, or P-3. In 14 (14.9%) patients, complications occurred at the C-1 or C-2 level. The analysis results revealed T-0 in 71 (75.5%), T-1 in 15 (15.9%), T-2 in 5 (5.3%), T-3 in 2 (2.1%), and T-4 in 1 (1. 1%) patient. Conclusions: A standardized analysis is crucial for evaluating the actual surgical results regarding patient satisfaction with microvascular decompression for refractory TGN. Based on our single-institute study with long-term follow-up, our method that combined separate outcomes for pain relief and complication occurrence into a single score effectively measured the actual subjective satisfaction of patients after surgery for TGN.

Abstract The aim of this study was to evaluate the influence of skin distortion due to surgical positioning on the clinical accuracy of the navigation system. The distance errors were measured in four fiducial markers (anterior, posterior, right, and left of the head) after the registration of the navigation system. The distance errors were compared between the surface-merge registration (SMR) method using preoperative imaging and the automatic intraoperative registration (AIR) method using intraoperative imaging. The comparison of the distance errors were performed in various surgical positions. The AIR method had the significant accuracy in the lateral markers than the SMR method (lateral position, 3.8 mm vs. 8.95 mm; p

We examined the stimulatory effects of lubiprostone, a bicyclic fatty acid derived from prostaglandin E1 and a chloride channel type-2 opener (ClC-2), on HCO3- secretion in the rat stomach and duodenum, with a focus on the EP receptor subtypes involved in this action. Under urethane anesthesia, an ex-vivo chambered stomach or a duodenal loop was perfused with saline, and HCO3- secretion was measured at pH 7.0 using a pH stat-method. Lubiprostone (0.1–30 μM) was perfused in the chamber or loop for 10 min. Indomethacin, ONO-8711 (an EP1 antagonist), or AE5-599 (an EP3 antagonist) was given s.c. 1 h before the lubiprostone treatment, while AE3-208 (an EP4 antagonist) or CFTRinh-172 (a cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor) was given i.p. 30 min before. Lubiprostone dose-dependently and significantly increased HCO3- secretion in both the stomach (≥ 10 μM) and duodenum (≥ 1 μM). The stimulatory effect in the stomach was significantly abrogated by a pretreatment with the EP1 antagonist, but not the EP3/EP4 antagonists or CFTR inhibitor, while that in the duodenum was significantly attenuated by the EP3/EP4 antagonists as well as the CFTR inhibitor. Indomethacin had no effect on the response of either tissue to lubiprostone. These results suggest that lubiprostone stimulated HCO3- secretion in the stomach and duodenum in a manner that was mediated by different EP receptor subtypes; the former was mediated by EP1 receptors, while the latter was mediated by both EP3 and EP4 receptors. CFTR/ClC-2 may be involved in the response observed in the duodenum, but not in the stomach.

The influence of adrenalectomy on indomethacin-induced enteropathy in rats was examined and the possible involvement of adrenal glucocorticoids in protective effects of urocortin I, a CRF agonist, was investigated. Male SD rats were administered indomethacin (10 mg/kg) s.c., killed 24 h later, and small intestines were examined for hemorrhagic lesions. Urocortin I (20 μg/kg) was given i.v. 10 min before indomethacin. Bilateral adrenalectomy was performed a week before the experiment. Indomethacin caused hemorrhagic lesions in small intestines, accompanied by intestinal hypermotility, enterobacterial invasion and iNOS expression. Adrenalectomy markedly increased ulcerogenic and motility responses caused by indomethacin, with further enhanced bacterial invasion and iNOS expression. This worsening effect was reproduced by pretreatment with mifepristone. Urocortin I prevented indomethacin-induced enteropathy; this effect was abrogated by astressin 2B, a CRF2 receptor antagonist, but was not affected by either adrenalectomy or mifepristone pretreatment. These results suggest that adrenalectomy aggravates indomethacin-induced enteropathy, and intestinal hypermotility response may be the key element in the mechanism underlying this aggravation, while endogenous glucocorticoids play a role in intestinal mucosal defense against these lesions but do not account for protective effects of urocortin I, which are mediated by peripheral CRF2 receptors.

Background: Boron neutron capture therapy (BNCT) is a nuclear reaction-based tumor cell-selective particle irradiation method. High-dose methotrexate and whole-brain radiation therapy (WBRT) are the recommended treatments for primary central nervous system lymphoma (PCNSL). This tumor responds well to initial treatment but relapses even after successful treatment, and the prognosis is poor as there is no safe and effective treatment for relapse. In this study, we aimed to conduct basic research to explore the possibility of using BNCT as a treatment for PCNSL. Methods: The boron concentration in human lymphoma cells was measured. Subsequently, neutron irradiation experiments on lymphoma cells were conducted. A mouse central nervous system (CNS) lymphoma model was created to evaluate the biodistribution of boron after the administration of borono-phenylalanine as a capture agent. In the neutron irradiation study of a mouse PCNSL model, the therapeutic effect of BNCT on PCNSL was evaluated in terms of survival. Results: The boron uptake capability of human lymphoma cells was sufficiently high both in vitro and in vivo. In the neutron irradiation study, the BNCT group showed a higher cell killing effect and prolonged survival compared with the control group. Conclusions: A new therapeutic approach for PCNSL is urgently required, and BNCT may be a promising treatment for PCNSL. The results of this study, including those of neutron irradiation, suggest success in the conduct of future clinical trials to explore the possibility of BNCT as a new treatment option for PCNSL.

GPR40/FFAR1 is a Gq protein-coupled receptor expressed in pancreatic β cells and enteroendocrine cells, and mediates insulin and incretin secretion to regulate feeding behavior. Several GPR40 full agonists have been reported to reduce food intake in rodents by regulating gut hormone secretion in addition to their potent glucose-lowering effects; however, detailed mechanisms of feeding suppression are still unknown. In the present study, we characterized T-3601386, a novel compound with potent full agonistic activity for GPR40, by using in vitro Ca2+ mobilization assay in Chinese hamster ovary (CHO) cells expressing FFAR1 and in vivo hormone secretion assay. We also evaluated feeding suppression and weight loss after the administration of T-3601386 and investigated the involvement of the vagal nerve in these effects. T-3601386, but not a partial agonist fasiglifam, increased intracellular Ca2+ levels in CHO cells with low FFAR1 expression, and single dosing of T-3601386 in diet-induced obese (DIO) rats elevated plasma incretin levels, suggesting full agonistic properties of T-3601386 against GPR40. Multiple doses of T-3601386, but not fasiglifam, in DIO rats showed dose-dependent weight loss accompanied by feeding suppression and durable glucagon-like peptide-1 elevation, all of which were completely abolished in Ffar1-/- mice. Immunohistochemical analysis in the nuclei of the solitary tract demonstrated that T-3601386 increased the number of c-Fos positive cells, which also disappeared in Ffar1-/- mice. Surgical vagotomy and drug-induced deafferentation counteracted the feeding suppression and weight loss induced by the administration of T-3601386. These results suggest that T-3601386 exerts incretin release and weight loss in a GPR40-dependent manner, and that afferent vagal nerves are important for the feeding suppression induced by GPR40 full agonism. Our novel findings raise the possibility that GPR40 full agonist can induce periphery-derived weight reduction, which may provide benefits such as less adverse effects in central nervous system compared to centrally-acting anti-obesity drugs.

Background: The development of effective boron compounds is a major area of research in the study of boron neutron capture therapy (BNCT). We created a novel boron compound, boronophenylalanine–amide alkyl dodecaborate (BADB), for application in BNCT and focused on elucidating how it affected a rat brain tumor model. Methods: The boron concentration of F98 rat glioma cells following exposure to boronophenylalanine (BPA) (which is currently being utilized clinically) and BADB was evaluated, and the biodistributions in F98 glioma-bearing rats were assessed. In neutron irradiation studies, the in vitro cytotoxicity of each boron compound and the in vivo corresponding therapeutic effect were evaluated in terms of survival time. Results: The survival fractions of the groups irradiated with BPA and BADB were not significantly different. BADB administered for 6 h after the termination of convection-enhanced delivery ensured the highest boron concentration in the tumor (45.8 μg B/g). The median survival time in the BADB in combination with BPA group showed a more significant prolongation of survival than that of the BPA group. Conclusion: BADB is a novel boron compound for BNCT that triggers a prolonged survival effect in patients receiving BNCT.

Taking the visual perspective of another individual is an important skill in social communication, and is termed visual perspective-taking (VPT). Individuals with autism spectrum disorder who have deficits in social interaction show relatively lower performance on VPT tasks than individuals who achieve age-appropriate developmental milestones. Thus, researchers have attempted to teach VPT skills and component behaviors to children with autism spectrum disorder. This pilot study evaluated the effects of a technology-based intervention on VPT skills in an adolescent male with autism spectrum disorder and moderate intellectual disabilities using a multiple-probe across behaviors design. Using a training package composed of multi-view videos with feedback, we trained the participant to discriminate whether the experimenter could see an object and to discriminate between right or left based on the experimenter's perspective. The results showed that the percentage of correct responses for each skill increased when the training package was applied. Furthermore, we observed generalization of VPT skills to untrained lab and natural environment settings. We discussed (1) the possibility that training multiple exemplars resulted in broad generalization, (2) the effectiveness of experiencing other people's perspectives when training VPT skills, and (3) the potential and limitations of multi-view videos for clinical application based on the results of the social validity questionnaire.

Boron neutron capture therapy (BNCT) is a form of tumor-cell selective particle irradiation using low-energy neutron irradiation of boron-10 (10B) to produce high-linear energy transfer (LET) alpha particles and recoiling 7Li nuclei (10B [n, alpha] 7Li) in tumor cells. Therefore, it is important to achieve the selective delivery of large amounts of 10B to tumor cells, with only small amounts of 10B to normal tissues. To develop practical materials utilizing 10B carriers, we designed and synthesized novel dodecaboranethiol (BSH)-containing kojic acid (KA-BSH). In the present study, we evaluated the effects of this novel 10B carrier on cytotoxicity, 10B concentrations in F98 rat glioma cells, and micro-distribution of KA-BSH in vitro. Furthermore, biodistribution studies were performed in a rat brain tumor model. The tumor boron concentrations showed the highest concentrations at 1 h after the termination of administration. Based on these results, neutron irradiation was evaluated at the Kyoto University Research Reactor Institute (KURRI) with KA-BSH. Median survival times (MSTs) of untreated and irradiated control rats were 29.5 and 30.5 days, respectively, while animals that received KA-BSH, followed by neutron irradiation, had an MST of 36.0 days (p = 0.0027, 0.0053). Based on these findings, further studies are warranted in using KA-BSH as a new B compound for malignant glioma.

Abstract.: Atrophic gastritis caused by infection with Helicobacter pylori is characterized by parietal cell loss, which is a main risk factor for gastric cancer. Parietal cells play a crucial role in the regulation of cell lineage maturation and proliferation in the gastric units. Among the classical cadherins, E-cadherin plays an important role not only in epithelial cell–cell connections, but also in the maintenance of epithelial polarity and gastric glandular architecture and regulation of cell proliferation. The aim of this study is to elucidate how parietal cells and E-cadherin are altered in gastritis with Helicobacter pylori infection. We studied the effects of Helicobacter pylori on gastric mucosal E-cadherin 2 weeks after inoculation and investigated the relationship between parietal cell loss and the amount of E-cadherin on parietal cells in Mongolian gerbils. The number of parietal cells and amount of staining of E-cadherin below the isthmus were investigated by immunohistochemistry. It was shown that a reduction in intercellular E-cadherin preceded the disappearance of parietal cells. The gastric glands where parietal cells were lost were replaced by mucus secreting cells without E-cadherin. These results suggest that Helicobacter pylori damaged E-cadherin on parietal cells and caused massive parietal cell loss, leading to the deregulation of gastric morphology. Keywords:: Helicobacter pylori, E-cadherin, gastritis, parietal cell, gastric

AbstractBackground/Aim: Muscarinic acetylcholine receptors exist in five subtypes (M1~M5), and they are widely expressed in various tissues to mediate diverse autonomic functions, including gastric secretion. In the present study, we demonstrated, using M1~M5 KO mice, the importance of M4 receptors in carbachol (CCh) stimulation of acid secretion and investigated how the secretion is modulated by the activation of M4 receptors. Methods: C57BL/6J mice of wild-type (WT) and M1-M5 KO were used. Under urethane anesthesia, acid secretion was measured in the stomach equipped with an acute fistula. CCh (30 µg/kg) was given s.c. to stimulate acid secretion. Atropine or octreotide (a somatostatin analogue) was given s.c. 20 min before the administration of CCh. CYN154806 (a somatostatin SST2 receptor antagonist) was given i.p. 20 min before the administration of octreotide or CCh. Results: CCh caused an increase of acid secretion in WT mice, and the effect was totally inhibited by prior administration of atropine. The effect of CCh was similarly observed in the animals lacking M1, M2 or M5 receptors but significantly decreased in M3 or M4 KO mice. CYN154806, the SST2 receptor antagonist, dose-dependently and significantly reversed the decreased acid response to CCh in M4 but not M3 KO mice. Octreotide, the somatostatin analogue, inhibited the secretion of acid under CCh-stimulated conditions in WT mice. The immunohistochemical study showed the localization of M4 receptors on D cells in the stomach. Serum somatostatin levels in M4 KO mice were higher than WT mice under basal conditions, while those in WT mice were significantly decreased in response to CCh. Conclusions: These results suggest that under cholinergic stimulation the acid secretion is directly mediated by M3 receptors and indirectly modified by M4 receptors. It is assumed that the activation of M4 receptors inhibits the release of somatostatin from D cells and minimizes the acid inhibitory effect of somatostatin through SST2 receptors, resulting in enhancement of the acid response mediated by M3 receptors on parietal cells.

Trelagliptin (SYR-472), a novel dipeptidyl peptidase-4 inhibitor, shows sustained efficacy by once-weekly dosing in type 2 diabetes patients. In this study, we characterized in vitro properties of trelagliptin, which exhibited approximately 4- and 12-fold more potent inhibition against human dipeptidyl peptidase-4 than alogliptin and sitagliptin, respectively, and >10,000-fold selectivity over related proteases including dipeptidyl peptidase-8 and dipeptidyl peptidase-9. Kinetic analysis revealed reversible, competitive and slow-binding inhibition of dipeptidyl peptidase-4 by trelagliptin (t1/2 for dissociation ≈ 30 minutes). X-ray diffraction data indicated a non-covalent interaction between dipeptidyl peptidase and trelagliptin. Taken together, potent dipeptidyl peptidase inhibition may partially contribute to sustained efficacy of trelagliptin.

We reviewed the effect of monosodium glutamate (MSG) on the development and healing of nonsteroidal anti-inflammatory drug (NSAID)-induced small intestinal lesions in rats. Loxoprofen (60 mg/kg, p.o.) induced lesions in the small intestine within 24 h, accompanied by a decrease of Muc2 expression and an increase in enterobacterial invasion and inducible nitric oxide synthase (iNOS) expression. These lesions were prevented when MSG was given as a mixture of powdered food for 5 days before the loxoprofen treatment. This effect of MSG was accompanied by an increase in Muc2 expression / mucus secretion as well as the suppression of bacterial invasion and iNOS expression. These intestinal lesions healed spontaneously within 6 days, but the process was impaired by the repeated administration of low-dose loxoprofen (30 mg/kg) for 5 days after the ulceration, with the decrease of vascular endothelial derived growth factor (VEGF) expression and angiogenesis. The healing-impairing effect of loxoprofen was prevented by feeding 5% MSG for 5 days after the ulceration. These results suggest that MSG not only prevents loxoprofen-induced small intestinal damage but also promotes a healing of these lesions; the former is functionally associated with the increase in Muc2 expression / mucus secretion and the suppression of bacterial invasion and iNOS expression, while the latter is associated with the stimulation of VEGF expression/angiogenesis. Keywords:: glutamate, loxoprofen, small intestinal damage, protective effect, healing-promoting effect, amino acid

Abstract.: We have reported that nicotine and the specific α7AChR agonist ameliorate indomethacin-induced intestinal lesions in mice by activating α7 nicotinic acetylcholine receptors (α7nAChR). Dopamine D2–receptor antagonists, such as domperidone and metoclopramide, enhance the release of ACh from vagal efferent nerves. The present study examined the effects of domperidone and metoclopramide on indomethacin-induced small intestinal ulceration in mice, focusing on the α7AChR. Male C57BL/6 mice were administered indomethacin (10 mg/kg, s.c.) and sacrificed 24 h later. Domperidone (0.1 – 10 mg/kg) and metoclopramide (0.03 – 0.3 mg/kg) were administered i.p. twice, at 0.5 h before and 8 h after indomethacin treatment, while methyllycaconitine (a selective antagonist of α7nAChR, 30 mg/kg) was administered twice, at 0.5 h before each domperidone treatment. Indomethacin caused severe hemorrhagic lesions in the small intestine, mostly to the jejunum and ileum, with a concomitant increase in myeloperoxidase (MPO) activity. Domperidone suppressed the severity of lesions and the increase in MPO activity at low doses (0.1 – 3 mg/kg), but not at a high dose (10 mg/kg). Similar effects were also observed by metoclopramide. The protective effects of domperidone and metoclopramide were totally abolished by prior administration of methyllycaconitine. Indomethacin treatment markedly enhanced inducible nitric oxide synthase and chemokine mRNA expression in the small intestine, but these responses were all significantly attenuated by either domperidone or metoclopramide. These findings suggest that dopamine D2–receptor antagonists ameliorate indomethacin-induced small intestinal ulceration through the activation of endogenous anti-inflammatory pathways mediated by α7nAChR. Keywords:: dopamine D2–receptor antagonist, α7 nicotinic acetylcholine receptor, indomethacin, small intestinal ulceration, chemokine

Abstract.: Endogenous prostaglandins (PGs) play an important role in modulating the mucosal integrity and various functions of the gastrointestinal tract, and E type PGs are most effective in these actions. PGE2 protected against acid-reflux esophagitis and prevented the development of gastric damage induced by ethanol or indomethacin, the effects mimicked by EP1 agonists and attenuated by an EP1 antagonist. Adaptive cytoprotection induced by mild irritants was also attenuated by the EP1 antagonist. On the other hand, the acid-induced duodenal damage was prevented by EP3/EP4 agonists and worsened by EP3/EP4 antagonists. Similarly, the protective effect of PGE2 on indomethacin-induced small intestinal damage or DSS-induced colitis was mimicked by EP3/EP4 agonists or EP4 agonists, respectively. The mechanisms underlying these actions of PGE2 are related to inhibition of stomach contraction (EP1), stimulation of duodenal HCO3− secretion (EP3/EP4), inhibition of small intestinal contraction (EP4), and stimulation of mucus secretion (EP3/EP4) or down-regulation of cytokine secretion in the colon (EP4), respectively. PGE2 also showed a healing-promoting effect on gastric ulcers and intestinal lesions through the activation of EP4 receptors, the effect associated with stimulation of angiogenesis via an increase in VEGF expression. These findings should aid the development of new strategies for treatment of gastrointestinal diseases. Keywords:: prostaglandin E, EP receptor subtype, mucosal protection, function, gastrointestinal tract

Ammonia is one of the important toxins produced by Helicobacter pylori (H. pylori), the major cause of peptic ulcer diseases. We examined whether glutamine or marzulene (a gastroprotective drug containing 1% sodium azulene and 99% glutamine) protects the gastric mucosa against H. pylori in vivo and investigated the mechanism underlying glutamine-induced mucosal protection against ammonia in gastric epithelial cells in vitro. Mongolian gerbils were fed for 3 months with a diet containing glutamine (2% – 20%) or marzulene (20%) starting from 2 weeks or 2 years after H. pylori infection. Then, gastric mucosal changes were evaluated both macro- and microscopically. Cultured gastric epithelial cells were incubated in the presence of ammonia, with or without glutamine; and cell viability, ammonia accumulation, and chemokine production were determined. Gerbils exhibited edema, congestion, and erosion after 3-month infection; and after 2-year infection, they showed cancer-like changes in the gastric mucosa. Glutamine and marzulene significantly suppressed these pathological changes caused in the gastric mucosa by H. pylori infection. Ammonia was accumulated in the cells, resulting in an increase in chemokine production and a decrease in cell viability. These pathological responses were prevented by glutamine. In addition, glutamine decreased chemokine production and cell death through inhibition of cellular accumulation of ammonia, resulting in the prevention of H. pylori–induced gastric diseases in vivo. These results suggest that glutamine/marzulene would be useful for prophylactic treatment of H. pylori–induced gastric diseases in patients. Keywords:: glutamine, gastric mucosa, Helicobacter pylori, protection, cell death, gastrointestinal tract

It was reported previously that non-steroidal anti-inflammatory drugs (NSAID)– induced gastric damage was markedly aggravated in rats during arthritis, and this response was mediated by the overproduction of nitric oxide (NO) derived from endothelial NO synthase (eNOS) in addition to inducible NO synthase (iNOS). The present study examined the gastric ulcerogenic response to cold-restraint stress in adjuvant arthritic rats, particularly in relation to NO/NOS isozymes. Exposure of normal rats to cold-restraint stress (13°C) produced slight gastric damage 3 h later, but the ulcerogenic response was markedly aggravated in arthritic rats. Pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) (a nonselective inhibitor of NOS) slightly increased the cold-restraint stress–induced gastric lesions in normal rats, but dose-dependently prevented the aggravation of these lesions in arthritic rats. The increased ulcerogenic response in arthritic rats was significantly suppressed by 1400W (a selective inhibitor of iNOS) and L-iminoethyl ornithine (L-NIO) (a selective inhibitor of eNOS), but not by NG-propyl-L-arginine (L-NPA) (a selective inhibitor of nNOS), and almost totally abolished by the coadministration of 1400W and L-NIO. The mucosal expression levels of eNOS and iNOS but not nNOS mRNAs were enhanced in arthritic rats compared with normal rats. The aggravation of stress-induced gastric lesions in arthritic rats was also significantly suppressed by pretreatment with glutathione. These results suggest that the gastric ulcerogenic response to cold-restraint stress is enhanced in arthritic rats, similar to that induced by NSAIDs, and this phenomenon may be causally associated with the upregulation of eNOS/NO in addition to iNOS/NO. Keywords:: nitric oxide (NO), endothelial NO synthase (eNOS), inducible NO synthase (iNOS), gastric damage, cold-restraint stress

The aim of the present study was to elucidate the pathogenic role of endogenous 5-HT in pancreatitis. Injections of cerulein at hourly intervals caused edematous pancreatitis in mice characterized by hyperenzymemia and histological alterations. While the cerulein-induced hyperenzymemia was attenuated in mice pretreated with p-CPA, a 5-HT depletor, it was exaggerated by the preferential 5-HT2A agonist (DOI), but not by the preferential 5-HT2B agonist (BW723C86) or the preferential 5-HT2C agonist (mCPP). Selective 5-HT2A antagonists (risperidone, spiperone, ketanserin, AMI-193, and MDL 11,939) dose-dependently attenuated the hyperenzymemia; and their potency order, excepting that of ketanserin which has considerable affinity at the 5-HT2C receptor as well, paralleled their reported pKi values at the 5-HT2A receptor. Selective 5-HT2B (SB204741) and 5-HT2C (SB242084) antagonists hardly affected the hyperenzymemia. Although the non-selective 5-HT2A/2B/2C antagonists (metergoline, ritanserin, and methysergide) dose-dependently attenuated the hyperenzymemia, they were relatively less potent compared to their high pKi values at the 5-HT2A receptor. In another set of experiments, risperidone, but not SB204741 and SB242084, dose-dependently reversed the cerulein-induced histological alteration of the pancreas (inflammatory cell infiltration). These results suggest that endogenously released 5-HT activates 5-HT2A receptors to aggravate cerulein-induced pancreatitis. We propose that selective 5-HT2A antagonists may provide a new therapy for acute pancreatitis. Keywords:: serotonin (5-HT), 5-HT2A-receptor activation, cerulein-induced acute pancreatitis, hyperenzymemia, histological alteration

We examined the effect of tacrolimus (FK506), an immunosuppressive drug, on indomethacin-induced small intestinal ulceration in rats. Animals were given indomethacin (10 mg/kg, s.c.), killed 24 h later, and myeloperoxidase (MPO) activity and thiobarbituric acid reactants (TBARS) were evaluated in intestinal lesions. Tacrolimus (0.3 – 3 mg/kg) was administered p.o. twice 0.5 h before and 6 h after indomethacin injection. The expression of inducible nitric oxide synthase (iNOS) mRNA was determined by a TaqMan real-time RT-PCR, while the activity of nuclear factor (NF)-κB DNA-binding was analyzed by electrophoresis mobility shift assays (EMSA) 6 h after indomethacin treatment. Indomethacin provoked severe hemorrhagic lesions in the small intestine, mainly in the jejunum and ileum, accompanied with increases in MPO activity and TBARS. Oral administration of tacrolimus reduced the severity of indomethacin-induced intestinal lesions in a dose-dependent manner. The increases in MPO activity and TBARS were also significantly attenuated by tacrolimus. The expression of iNOS mRNA was markedly enhanced when examined 6 h after indomethacin administration, and this response was counteracted by tacrolimus. Indomethacin also activated NF-κB in a tacrolimus-preventable manner. These results suggest that tacrolimus prevents indomethacin-induced small intestinal ulceration in the rat. This effect may be due to inhibition of iNOS induction through suppression of NF-κB activation. Keywords:: tacrolimus (FK506), indomethacin, small intestinal ulceration, inducible nitric oxide synthase (iNOS), nuclear factor (NF)-κB

Gastric ulcer disease remains widespread; a stressful lifestyle and nonsteroidal antiinflammatory drugs (NSAIDs) make significant contributions to this pathological situation. The findings overviewed here support the idea that glucocorticoid hormones released in response to acute stress or NSAIDs act as gastroprotective substances and exert many of the same actions in the stomach as prostaglandins (PGs) and nitric oxide (NO) as well as capsaicin-sensitive afferent neurons. Glucocorticoids exert a gastroprotective effect by both maintaining local defensive factors (mucosal blood flow and mucus production) and inhibiting pathogenic elements (gastric motility and microvascular permeability). Furthermore, they exert gastroprotective actions in co-operation with PGs, NO, and the afferent neurons; and their compensatory action is observed when the protective mechanism provided by either of these factors is impaired. The gastroprotective action of glucocorticoids is also associated with maintenance of general body homeostasis, including blood glucose levels and systemic blood pressure. In conclusion, glucocorticoids released in response to acute stress or NSAIDs are naturally occurring protective factors that play an important role in maintenance of the gastric mucosal integrity. This led us to re-evaluate the traditional paradigm that glucocorticoid hormones produced during activation of the hypothalamic-pituitary-adrenocortical axis are ulcerogenic in the stomach. Keywords:: hypothalamic-pituitary-adrenocortical axis, glucocorticoid hormone, stress- and nonsteroidal antiinflammatory drug (NSAID)-induced gastric erosion, gastroprotection

ABSTRACT: We examined the effect of lafutidine, a novel histamine H2-receptor antagonist, on acid reflux esophagitis in rats in relation to capsaicin-sensitive afferent neurons. The esophagitis was induced in rats by ligating both the pylorus and forestomach for 4 h. Lafutidine (1 – 30 mg/kg) and cimetidine (100 mg/kg) were administered either intragastrically or intraduodenally, while capsaicin (1 – 30 mg/kg) was administered intragastrically after the dual ligation. Intragastrical administered lafutidine at >3 mg/kg significantly prevented the hemorrhagic esophageal damage induced by the dual ligation, and this effect was mimicked by neither capsaicin nor cimetidine given intragastrically, but totally abolished by sensory deafferentation. In contrast, lafutidine and cimetidine given intraduodenally were both protective against the esophageal damage in a sensory deafferentation-resistant manner. The acid secretion in pylorus-ligated stomachs was significantly inhibited by these agents given intraduodenally, but not intragastrically. Vanilloid receptor subtype 1 (VR1) was expressed abundantly in the stomach, but very weakly expressed in the esophagus as assessed by Western blotting. These results suggest that lafutidine is effective against the esophageal lesions induced by acid reflux through inhibition of acid secretion and capsaicin-sensitive afferent neurons. The latter mechanism, not shared by cimetidine, may be due to the interaction of lafutidine with unidentified sites on sensory neurons other than VR1.

Selective free fatty acid receptor 1 (FFAR1)/GPR40 agonist fasiglifam (TAK-875), an antidiabetic drug under phase 3 development, potentiates insulin secretion in a glucose-dependent manner by activating FFAR1 expressed in pancreatic β cells. Although fasiglifam significantly improved glycemic control in type 2 diabetes patients with a minimum risk of hypoglycemia in a phase 2 study, the precise mechanisms of its potent pharmacological effects are not fully understood. Here we demonstrate that fasiglifam acts as an ago-allosteric modulator with a partial agonistic activity for FFAR1. In both Ca(2+) influx and insulin secretion assays using cell lines and mouse islets, fasiglifam showed positive cooperativity with the FFAR1 ligand γ-linolenic acid (γ-LA). Augmentation of glucose-induced insulin secretion by fasiglifam, γ-LA, or their combination was completely abolished in pancreatic islets of FFAR1-knockout mice. In diabetic rats, the insulinotropic effect of fasiglifam was suppressed by pharmacological reduction of plasma free fatty acid (FFA) levels using a lipolysis inhibitor, suggesting that fasiglifam potentiates insulin release in conjunction with plasma FFAs in vivo. Point mutations of FFAR1 differentially affected Ca(2+) influx activities of fasiglifam and γ-LA, further indicating that these agonists may bind to distinct binding sites. Our results strongly suggest that fasiglifam is an ago-allosteric modulator of FFAR1 that exerts its effects by acting cooperatively with endogenous plasma FFAs in human patients as well as diabetic animals. These findings contribute to our understanding of fasiglifam as an attractive antidiabetic drug with a novel mechanism of action.

High-mobility group box 1 (HMGB1) was initially discovered as a nuclear protein that interacts with DNA as a chromatin-associated non-histone protein to stabilize nucleosomes and to regulate the transcription of many genes in the nucleus. Once leaked or actively secreted into the extracellular environment, HMGB1 activates inflammatory pathways by stimulating multiple receptors, including Toll-like receptor (TLR) 2, TLR4, and receptor for advanced glycation end products (RAGE), leading to tissue injury. Although HMGB1's ability to induce inflammation has been well documented, no studies have examined the role of HMGB1 in wound healing in the gastrointestinal field. The aim of this study was to evaluate the role of HMGB1 and its receptors in the healing of gastric ulcers. We also investigated which receptor among TLR2, TLR4, or RAGE mediates HMGB1's effects on ulcer healing. Gastric ulcers were induced by serosal application of acetic acid in mice, and gastric tissues were processed for further evaluation. The induction of ulcer increased the immunohistochemical staining of cytoplasmic HMGB1 and elevated serum HMGB1 levels. Ulcer size, myeloperoxidase (MPO) activity, and the expression of tumor necrosis factor α (TNFα) mRNA peaked on day 4. Intraperitoneal administration of HMGB1 delayed ulcer healing and elevated MPO activity and TNFα expression. In contrast, administration of anti-HMGB1 antibody promoted ulcer healing and reduced MPO activity and TNFα expression. TLR4 and RAGE deficiency enhanced ulcer healing and reduced the level of TNFα, whereas ulcer healing in TLR2 knockout (KO) mice was similar to that in wild-type mice. In TLR4 KO and RAGE KO mice, exogenous HMGB1 did not affect ulcer healing and TNFα expression. Thus, we showed that HMGB1 is a complicating factor in the gastric ulcer healing process, which acts through TLR4 and RAGE to induce excessive inflammatory responses.