Efficacy of Boron Neutron Capture Therapy in Primary Central Nervous System Lymphoma: In Vitro and In Vivo Evaluation.

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.

Mucosal protective agents prevent exacerbation of NSAID-induced small intestinal lesions caused by antisecretory drugs in rats.

Antisecretory drugs such as histamine H2-receptor antagonists and proton pump inhibitors are commonly used for the treatment of upper gastrointestinal mucosal lesions induced by nonsteroidal anti-inflammatory drugs (NSAIDs). However, it has recently been reported that these drugs exacerbate NSAID-induced small intestinal lesions in rats. Unfortunately, there are few effective agents for the treatment of this complication. We examined the effects of mucosal protective agents (MPAs) (misoprostol, irsogladine, and rebamipide) and mucin of porcine stomach on diclofenac-induced intestinal lesions and the exacerbation of the lesions by ranitidine or omeprazole. The effects of the drugs on intestinal motility and mucus distribution/content were also examined. Male Wistar rats (180-220 g) were used. Each drug was administered orally under fed conditions. Diclofenac (1-10 mg/kg) produced multiple lesions in the small intestine dose-dependently. Both ranitidine (30 mg/kg) and omeprazole (100 mg/kg) significantly increased the intestinal lesions induced by low doses (3 and 6 mg/kg) of diclofenac. Misoprostol (0.03-0.3 mg/kg), irsogladine (3-30 mg/kg), and rebamipide (30-300 mg/kg), as well as mucin (30-300 mg/kg) inhibited the formation of intestinal lesions caused by a high dose (10 mg/kg) of diclofenac alone and prevented the exacerbation of diclofenac-induced lesions by antisecretory drugs. Diclofenac (10 mg/kg) markedly increased the intestinal motility and decreased the mucosal mucus, and the decrease of mucus was significantly inhibited by the MPAs. These results indicate the usefulness of the MPAs for the treatment of intestinal lesions induced by NSAIDs alone or by coadministration with antisecretory drugs, and suggest that mucus plays an important role in the protection of intestinal mucosa by the MPAs.

Exacerbation of nonsteroidal anti-inflammatory drug-induced small intestinal lesions by antisecretory drugs in rats: the role of intestinal motility.

Antisecretory drugs such as histamine H2-receptor antagonists (H2-RAs) and proton pump inhibitors (PPIs) are commonly used for the treatment of gastric and duodenal ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs). However, the effects of these drugs on NSAID-induced small intestinal ulcers are not fully understood. The effects of H2-RAs and PPIs on NSAID-induced gastrointestinal lesions and small intestinal motility were examined in rats. Male Wistar rats (180-220 g) were used. Indomethacin (10 mg/kg) was administered orally in fasted or fed rats, and gastrointestinal lesions were examined 24 h after indomethacin administration. Intestinal motility was measured by using a balloon method under urethane anesthesia. Indomethacin produced multiple lesions in the gastric corpus in fasted rats and in the small intestine in fed rats: 1) H2-RAs (cimetidine, ranitidine, and famotidine) and PPIs (omeprazole, lansoprazole, and rabeprazole) markedly inhibited the formation of gastric lesions. 2) The drugs, except for lansoprazole, increased intestinal lesions. 3) H2-RAs augmented the increase in intestinal motility caused by indomethacin, and the effects of H2-RAs on motility and intestinal lesions were markedly inhibited by atropine. 4) Lansoprazole inhibited the formation of intestinal lesions, and the effect was prevented by both pharmacological ablation of capsaicin-sensitive sensory neurons and pretreatment with N-nitro-l-arginine methyl ester, a selective inhibitor of nitric-oxide synthesis. The results suggest that: 1) inhibition of acid secretion by antisecretory drugs may exacerbate NSAID-induced intestinal lesions, 2) H2-RAs further aggravate lesions by increasing intestinal motility via the activation of cholinergic pathways, and 3) lansoprazole protects the intestinal mucosa against NSAID-related ulcerative stimuli.

[Prophylactic effect of glutamate on gastrointestinal damage].

Glutamate is known as the umami substance in the diet and umami taste has been traditionally preferred in East Asian countries. Recent our and others' studies showed that glutamate has potential to protect the gastrointestinal mucosa against noxious agents. In contrast, Helicobacter pylori infection and non-steroidal anti-inflammatory drugs (NSAIDs) are recognized as the two major causes of gastrointestinal diseases characterized by gastritis or gastrointestinal ulcers. We examined whether dietary supplementation of glutamate prevents the Helicobacter pylori infection- and NSAIDs-induced gastrointestinal damages in animal models. In this paper, we first review how these noxious agents develop gastrointestinal damages, and secondly discuss the possible candidates of protective factors as well as the mechanisms how glutamate prevents these gastrointestinal damages. We propose that our daily intake of glutamate has important roles in protecting the gastrointestinal mucosa against Helicobacter pylori and NSAIDs and possibly contributes to the maintenance of our healthy lives.

Measurement of small intestinal damage.

Many animal models have been devised for investigating the pathogenesis of intestinal lesions and for screening drugs for the treatment of intestinal ulcers in humans. Recently, particular attention has been focused on NSAID-induced intestinal lesions as a result of the development of the capsule endoscope and double-balloon endoscope. Ischemic enteritis, one of the most dramatic abdominal emergencies, is known to cause severe damage to the small intestine by a significant decrease of arterial blood flow in the small intestine. In this unit, two animal models for small intestinal damage induced by NSAIDs or intestinal ischemia are described. Also included are methods for lesion induction and evaluation of the damage as well as the measurement of pathogenic functional and biochemical changes.

Aggravation of cold-restraint stress-induced gastric lesions in adjuvant arthritic rats: pathogenic role of inducible and endothelial nitric oxide.

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 degrees C) produced slight gastric damage 3 h later, but the ulcerogenic response was markedly aggravated in arthritic rats. Pretreatment with N(G)-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 1400 W (a selective inhibitor of iNOS) and L-iminoethyl ornithine (L-NIO) (a selective inhibitor of eNOS), but not by N(G)-propyl-L-arginine (L-NPA) (a selective inhibitor of nNOS), and almost totally abolished by the co-administration of 1400 W 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.

The dipeptidyl peptidase-4 inhibitor alogliptin in combination with pioglitazone improves glycemic control, lipid profiles, and increases pancreatic insulin content in ob/ob mice.

The combination of two agents with different but complementary mechanisms of action is a logical approach for treating patients with type 2 diabetes. Thus, we evaluated chronic combination therapy with alogliptin, a highly selective dipeptidyl peptidase-4 inhibitor that enhances the action of incretins, and pioglitazone, a thiazolidinedione that improves peripheral and hepatic insulin sensitivity. Studies were designed to investigate the chronic metabolic and pancreatic effects of alogliptin (0.03%) plus pioglitazone (0.003%) combination treatment in obese ob/ob mice. After 4-5 weeks of treatment, alogliptin significantly increased plasma active glucagon-like peptide-1 levels up to 4.1-fold and decreased plasma glucagon up to 25%, whereas pioglitazone significantly increased plasma adiponectin up to 1.3-fold. Combination treatment exhibited a complementary effect, increasing plasma insulin levels by 3.2-fold (alogliptin alone, 1.6-fold; pioglitazone alone, 1.5-fold) and decreasing glycosylated hemoglobin by 2.3% (alogliptin alone, 1.0%; pioglitazone alone, 1.5%), and non-fasting and fasting plasma glucose by 37% and 62% (alogliptin alone, 17% and 24%; pioglitazone alone, 30% and 45%), respectively. Combination treatment also decreased plasma triglycerides by 67% and non-esterified fatty acids by 25% (alogliptin alone, 24% and 11%; pioglitazone alone, 54% and 8%). Moreover, combination treatment increased pancreatic insulin content by 2.2-fold (alogliptin alone, 1.3-fold; pioglitazone alone, 1.6-fold), with no significant changes in body weight. These results indicate that combination treatment with alogliptin and pioglitazone improved glycemic control, lipid profiles and increased pancreatic insulin content in ob/ob mice by preventing incretin inactivation and improving insulin resistance. These results provide a strong argument for using alogliptin in combination with pioglitazone.

Risperidone attenuates local and systemic inflammatory responses to ameliorate diet-induced severe necrotic pancreatitis in mice: it may provide a new therapy for acute pancreatitis.

In a previous article, we showed that a potent serotonin-, 5-hydroxytryptamine-2A (5-HT(2A)) antagonist, risperidone, ameliorated cerulein-induced edematous pancreatitis in mice. In the present article, young female mice were fed a choline-deficient, ethionine-supplemented diet. All of the mice developed severe necrotic pancreatitis, and approximately 50% of them died within 4 days. Serum levels of proinflammatory interleukin (IL)-6 significantly increased on day 3 and returned toward the control on day 4 of choline-deficient ethionine-supplemented (CDE) diet treatment. The time course of IL-6 levels paralleled those of plasma amylase and lipase activities. On the other hand, platelet counts significantly decreased on day 3, and the change became more marked on day 4, coinciding with mortality and histological alterations of the pancreas (edema, inflammatory cell infiltration, necrosis). Preceding these changes, plasma levels of 5-hydroxyindoleacetic acid (5-HIAA) increased on feeding a CDE diet to reach a peak on day 3 and returned toward the control on day 4. Risperidone (0.1-3.2 mg/kg twice a day) hardly affected the 5-HIAA levels but dose-dependently attenuated the serum IL-6 levels, plasma amylase/lipase levels, platelet counts, histological alterations, and mortality of diet-induced pancreatitis mice. These results are discussed in relation to the pathogenesis of acute pancreatitis. Thus, we speculate that acinar cell injury triggers local inflammatory reactions and, if coincided with enhanced IL-6 release, leads to a systemic inflammatory response syndrome, which is responsible for the mortality. In addition, it is suggested that diet-induced 5-HT release and 5-HT(2A) receptor activation are involved in this whole process of pancreatitis development. Risperidone may provide a new therapy for the disease.

Impairment by 5-fluorouracil of the healing of gastric lesions in rats: effect of lafutidine, a histamine H2 receptor antagonist, mediated by capsaicin-sensitive afferent neurons.

We investigated the influence of 5-fluorouracil (5-FU), an anti-tumor agent, on the healing of gastric lesions generated by 0.6 M HCl in rats and the effect of lafutidine, a histamine H(2) receptor antagonist, on the impaired healing. Animals fasted for 18 h were given 1 ml of 0.6 M HCl p.o., fed normally from 1 h later, and killed 1-96 h thereafter. 5-FU was given i.v. twice, 1 h and 24 h after the HCl. The gastric lesions healed spontaneously within 96 h. Although it decreased acid secretion, 5-FU markedly delayed the healing. Lafutidine, but not cimetidine, given p.o. immediately after each dosing of 5-FU significantly reversed the delay in healing by 5-FU, and this effect was attenuated by the chemical ablation of capsaicin-sensitive afferent neurons. Capsaicin also significantly reversed the delay in healing. The mucosal application of 50 mM HCl did not affect gastric mucosal blood flow (GMBF) in the normal stomach, but significantly increased it in the stomach damaged by 0.6 M HCl. The increases in GMBF were attenuated by 5-FU; however, the co-administration of lafutidine significantly restored the response. In addition, 5-FU inhibited both cell proliferation and migration in rat gastric epithelial cells (RGM1) in vitro. These results suggest that 5-FU delayed the healing of gastric lesions generated by 0.6 M HCl, probably through the inhibition of cell migration and proliferation, as well as the impairment of GMBF, and lafutidine reversed the delay in healing, mainly through the amelioration of the GMBF response mediated by capsaicin-sensitive afferent neurons.

Preconditioning stress prevents cold restraint stress-induced gastric lesions in rats: roles of COX-1, COX-2, and PLA2.

We investigated the protective effect of mild stress on gastric lesions induced by cold-restraint stress, especially concerning prostaglandins (PGs)/cyclo-oxygenase (COX) isozymes. Rats were exposed to severe stress (cold-restraint stress at 10 degrees C for 6 hr) or mild stress (cold-restraint stress at 10 degrees C for 30 min and kept at room temperature for 60 min) followed by severe stress. Severe stress induced gastric lesions, with a concomitant decrease in body temperature (BT). The ulcerogenic response was inhibited by atropine but worsened by indomethacin and SC-560 but not rofecoxib, although none of these agents had any effect on the change in BT. Mild stress suppressed the gastric ulceration and the decrease in BT induced by severe stress, and these effects were reversed by both COX-1 and COX-2 inhibitors. The expression of COX-2 in the stomach was up-regulated from 4 hr after severe stress and this response was slightly expedited by mild stress. COX-2 was also expressed in the hypothalamus under normal and stressed conditions. Quinacrine (phospholipase A(2) inhibitor) attenuated the protective effect of mild stress on the ulceration and decrease in BT caused by severe stress. TA-0910 (TRH analogue) at a low dose also prevented the gastric ulceration and the decrease in BT induced by severe stress. These results suggest that mild stress protects against cold-restraint stress-induced gastric ulceration, and the effect is peripherally and centrally mediated by PGs derived from both COX-1 and COX-2 through the activation of phospholipase A(2). TRH may also be involved in the protective effect of mild stress, probably through regulation of the thermogenic system.

Protective effect of lafutidine, a novel H2-receptor antagonist, on reflux esophagitis in rats through capsaicin-sensitive afferent neurons.

We examined the effect of lafutidine, a novel histamine H(2)-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.

Facilitation by endogenous prostaglandins of capsaicin-induced gastric protection in rodents through EP2 and IP receptors.

We investigated the role that prostaglandins (PGs) and EP receptors play in facilitating the gastroprotective action of capsaicin against HCl/ethanol in rats and mice. Male Sprague-Dawley rats and C57BL/6 mice were used after 18 h of fasting. The animals were given HCl/ethanol (60% in 150 mM HCl) p.o. and killed 1 h later. Capsaicin or various EP agonists were given p.o. 30 min or i.v. 10 min before HCl/ethanol. In some cases, indomethacin or various EP agonists were given s.c. 30 min or i.v 10 min before capsaicin, respectively. Gastric lesions induced by HCl/ethanol were significantly inhibited by PGE(2) as well as capsaicin. The effect of PGE(2) was antagonized by ONO-AE-829 (EP1 antagonist), whereas the capsaicin action was mitigated by indomethacin as well as sensory deafferentation but not by ONO-AE-829. The generation of mucosal PGE(2) was not affected by either capsaicin or sensory deafferentation, but was significantly inhibited by indomethacin. Although neither butaprost (EP2), ONO-NT-012 (EP3), nor 11-deoxy PGE1 (EP4) alone had any effect on HCl/ethanol-induced gastric lesions, only butaprost restored the protective action of capsaicin in the presence of indomethacin. Capsaicin provided a protective action against HCl/ethanol-induced gastric lesions in wild-type (+/+) mice in an indomethacin-sensitive manner, and this action was similarly observed in EP1 (-/-) and EP3 (-/-) mice but not in the animals lacking IP receptors. These results suggest that capsaicin exhibits gastric cytoprotection, essentially by stimulating sensory neurons, and this action is facilitated by endogenous PGs through EP2/IP receptors, probably sensitizing the sensory neurons to capsaicin.

Ulcerogenic influence of selective cyclooxygenase-2 inhibitors in the rat stomach with adjuvant-induced arthritis.

Cyclooxygenase (COX)-2 inhibitors have been developed as new gastric sparing anti-inflammatory drugs. We previously reported that the ulcerogenic response to conventional nonselective COX inhibitors, such as indomethacin and aspirin, was markedly increased in arthritic rats. The ulcerogenic effect of selective COX-2 inhibitors in arthritic animals, however, remains unknown. The present study was designed to examine the influence of selective COX-2 inhibitors, such as rofecoxib and celecoxib, on gastric mucosal integrity in rats with adjuvant-induced arthritis. Arthritis was induced in male dark Agouti rats by injection of Freund's complete adjuvant into the right hind paw. Two weeks after the injection, the animals were fasted for 18 h, various COX inhibitors were administered orally, and the mucosa was examined for lesions 4 h later. Oral administration of indomethacin caused hemorrhagic gastric lesions in both normal and arthritic rats, although the severity of lesions was significantly greater in the latter group. In contrast, neither rofecoxib nor celecoxib caused any gastric damage in normal rats, but both drugs provoked hemorrhagic gastric lesions in arthritic rats. The expression of COX-2 mRNA and immuno-positive cells was observed in the gastric mucosa of arthritic but not normal rats. The gastric mucosal prostaglandin (PG) E(2) content was significantly elevated in arthritic rats in a rofecoxib-sensitive manner. In conclusion, COX-2 inhibitors produce gastric lesions in arthritic rats, similar to the nonselective COX-inhibitors. COX-2 is up-regulated in the stomach of arthritic rats, and PGs produced by COX-2 play a role in maintaining the integrity of the gastric mucosa.

Pathogenic importance of intestinal hypermotility in NSAID-induced small intestinal damage in rats.

BACKGROUND/AIM: Nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin produce damage in the small intestine as a major adverse reaction. We examined the effect of various NSAIDs on intestinal motility and investigated the pathogenic importance of motility changes in the intestinal ulcerogenic response to indomethacin in rats. METHODS: Animals without fasting were given various NSAIDs (indomethacin 10 mg/kg, diclofenac 40 mg/kg, flurbiprofen 20 mg/kg, naproxen 40 mg/kg) s.c., and in the case of indomethacin, the following parameters were examined in the small intestine 24 h later; the lesion score, the number of enterobacteria and myeloperoxidase (MPO) as well as inducible nitric oxide (iNOS) activity. Intestinal motility was monitored as intraluminal pressure recordings using a balloon under anesthesia. RESULTS: All NSAIDs tested decreased mucosal PGE(2) levels and produced hemorrhagic lesions in the small intestine, accompanied by intestinal hypermotility. As representative of NSAIDs, indomethacin also increased the extent of enterobacterial invasion and MPO as well as iNOS activity before the occurrence of intestinal damage, and the hypermotility response was observed earlier than the onset of any other event caused by this agent. The intestinal lesions induced by indomethacin were prevented by either supplementation with dmPGE(2), inhibition of bacterial invasion with ampicillin or inhibition of iNOS activity with aminoguanidine, while the hypermotility response was prevented by dmPGE(2) only. In addition, the observed effects of dmPGE(2) were all mimicked by atropine when the intestinal hypermotility was suppressed by this agent. CONCLUSION: These results suggest the pathogenic importance of intestinal hypermotility in the intestinal ulcerogenic response to NSAIDs in rats and show that this event is critical for the occurrence of enterobacterial invasion under PG deficiency, followed by various inflammatory changes and damage in the mucosa. This study also suggests that the antispasmodic drug is protective against NSAID-induced intestinal lesions.

Alteration of gastric ulcerogenic and healing responses in rats with adjuvant-induced arthritis.

Gastroenteropathy is the most common among patients who use non-steroidal anti-inflammatory drugs (NSAIDs) for treatment of inflammatory disorders. It is known that rheumatoid arthritic patients are more susceptible to NSAID-induced gastropathy than other NSAID users. This article reviewed our recent studies concerning the influence of arthritic conditions on gastric ulcerogenic response to NSAID and healing response of chronic gastric ulcers in rats. Gastric lesions induced by indomethacin, one of the conventional NSAIDs, were markedly aggravated in arthritic rats. This increased ulcerogenic response in arthritic rats was attributable to nitric oxide production due to up-regulation of inducible nitric oxide synthase. In arthritic rat stomachs, cyclooxygenase (COX)-2 was also up-regulated, where COX-2 selective inhibitors such as rofecoxib or celecoxib provoked gross lesions, although they caused no damage in normal rats. In addition, the healing of chronic gastric ulcers was also delayed in arthritic rats because of less expression of various growth factors such as basic fibroblast growth factors or insulin-like growth factors. Based on these findings, it is concluded that arthritic conditions alter the mucosal ulcerogenic and healing responses in the stomach. Especially, caution should be paid on the use of COX-2 selective inhibitors in rheumatoid arthritic patients.