Teita Asano

Synthesis and biological evaluation of derivatives of 2-{2-fluoro-4-[(2- oxocyclopentyl)methyl]phenyl}propanoic acid: Nonsteroidal anti-inflammatory drugs with low gastric ulcerogenic activity

We previously reported that 2-fluoroloxoprofen has lower gastric ulcerogenic activity than loxoprofen, a nonsteroidal anti-inflammatory drug (NSAID) without selectivity for COX-2. We synthesized derivatives of 2-fluoroloxoprofen and studied their properties. Compared to 2-fluoroloxoprofen, one derivative, 11a, exhibited higher anti-inflammatory activity and an equivalent ulcerogenic effect. These results suggest that 11a could be therapeutically beneficial for use as an NSAID.

Stimulation of gastric ulcer healing by heat shock protein 70.

It is important in treatment of gastric ulcers to not only prevent further ulcer formation but also enhance ulcer healing. When cells are exposed to gastric irritants, expression of heat shock proteins (HSPs) is induced, making the cells resistant to the irritants. We recently reported direct evidence that HSPs, especially HSP70, are preventive against irritant-induced gastric ulcer formation. Gastric ulcer healing is a process involving cell proliferation and migration at the gastric ulcer margin and angiogenesis in granulation tissue. In this study, we have examined the role of HSP70 in gastric ulcer healing. Gastric ulcers were produced by focal and serosal application of acetic acid. Expression of HSP70 was induced in both the gastric ulcer margin and granulation tissue. Compared with wild-type mice, gastric ulcer healing was accelerated in transgenic mice expressing HSP70, and both cell proliferation at the gastric ulcer margin and angiogenesis in granulation tissue were enhanced. Oral administration of geranylgeranylacetone, an inducer of HSPs, to wild-type mice, either prior to or after ulcer formation, not only induced expression of HSP70 in the stomach but also accelerated gastric ulcer healing. On the other hand, oral administration of purified recombinant HSP70 prior to the ulcer formation, but not after formation, stimulated gastric ulcer healing. This study provides the first evidence that HSP70 accelerates gastric ulcer healing. The results also suggest that both the HSP70 produced prior to ulcer formation and released from damaged cells, and the HSP70 produced after ulcer formation are involved in this accelerated healing process.

Aldioxa improves delayed gastric emptying and impaired gastric compliance, pathophysiologic mechanisms of functional dyspepsia

Delayed gastric emptying and impaired gastric accommodation (decreased gastric compliance) play important roles in functional dyspepsia (FD). Here we screen for a clinically used drug with an ability to improve delayed gastric emptying in rats. Oral administration of aldioxa (dihydroxyaluminum allantoinate) partially improved clonidine- or restraint stress-induced delayed gastric emptying. Administration of allantoin, but not aluminium hydroxide, restored the gastric emptying. Both aldioxa and allantoin inhibited clonidine binding to the α-2 adrenergic receptor, suggesting that antagonistic activity of the allantoin moiety of aldioxa on this receptor is involved in the restoration of gastric emptying activity. Aldioxa or aluminium hydroxide but not allantoin restored gastric compliance with restraint stress, suggesting that aluminium hydroxide moiety is involved in this restoration. We propose that aldioxa is a candidate drug for FD, because its safety in humans has already been confirmed and its ameliorating effect on both of delayed gastric emptying and impaired gastric compliance are confirmed here.

Effects of β-(1,3-1,6)-D-glucan on irritable bowel syndrome-related colonic hypersensitivity.

Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by chronic abdominal pain associated with altered bowel habits. Since the prevalence of IBS is very high and thus, involves elevated health-care costs, treatment of this condition by methods other than prescribed medicines could be beneficial. β-(1,3)-D-glucan with β-(1,6) branches (β-glucan) has been used as a nutritional supplement for many years. In this study, we examined the effect of β-glucan on fecal pellet output and visceral pain response in animal models of IBS. Oral administration of β-glucan suppressed the restraint stress- or drug-induced fecal pellet output. β-Glucan also suppressed the visceral pain response to colorectal distension. These results suggest that β-glucan could be beneficial for the treatment and prevention of IBS.

Ameliorative Effect of Mepenzolate Bromide against Pulmonary Fibrosis

Idiopathic pulmonary fibrosis is thought to involve lung injury caused by reactive oxygen species (ROS), which in turn is followed by abnormal fibrosis. A transforming growth factor (TGF)-β1–induced increase in myofibroblast number plays an important role in this abnormal fibrosis. We recently found that mepenzolate bromide (mepenzolate), which has been used clinically to treat gastrointestinal disorders, has ROS-reducing properties. In the present study, we examined the effect of mepenzolate on bleomycin-induced pulmonary fibrosis and lung dysfunction in mice. The severity of pulmonary fibrosis was assessed by histopathologic evaluation and determination of hydroxyproline levels. Lung mechanics (elastance) and respiratory function [forced vital capacity (FVC)] were assessed using a computer-controlled ventilator. Respiratory function was also evaluated by monitoring percutaneous arterial oxygen saturation (SpO2). Intratracheal administration of mepenzolate prior to bleomycin treatment reduced the extent of pulmonary fibrosis and changes in lung mechanics and led to a significant recovery of both FVC and SpO2 compared with control. Furthermore, mepenzolate produced a therapeutic effect even when it was administered after the development of fibrosis. Administration of mepenzolate also prevented bleomycin-induced pulmonary cell death and inflammatory responses and increased myofibroblast number. Mepenzolate also decreased NADPH oxidase activity and active TGF-β1 level or increased glutathione S-transferase (GST) activity in the presence of bleomycin treatment. These results show that the intratracheal administration of mepenzolate reduced bleomycin-induced pulmonary fibrosis and lung dysfunction in mice. These effects may be due to this drug’s inhibitory effect on NADPH oxidase and TGF-β1 activities and its stimulatory effect on GST.

Superiority of pulmonary administration of mepenzolate bromide over other routes as treatment for chronic obstructive pulmonary disease

We recently proposed that mepenzolate bromide (mepenzolate) would be therapeutically effective against chronic obstructive pulmonary disease (COPD) due to its both anti-inflammatory and bronchodilatory activities. In this study, we examined the benefits and adverse effects associated with different routes of mepenzolate administration in mice. Oral administration of mepenzolate caused not only bronchodilation but also decreased the severity of elastase-induced pulmonary emphysema; however, compared with the intratracheal route of administration, about 5000 times higher dose was required to achieve this effect. Intravenously or intrarectally administered mepenzolate also showed these pharmacological effects. The intratracheal route of mepenzolate administration, but not other routes, resulted in protective effects against elastase-induced pulmonary damage and bronchodilation at a much lower dose than that which affected defecation and heart rate. These results suggest that the pulmonary route of mepenzolate administration may be superior to other routes (oral, intravenous or intrarectal) to treat COPD patients.

Anethole restores delayed gastric emptying and impaired gastric accommodation in rodents

Functional dyspepsia (FD), a functional gastrointestinal disorder, is characterized by persistent or recurrent postprandial upper abdominal discomfort and epigastric pain. The high prevalence of FD and associated healthcare costs suggests that treatment of this condition by methods other than prescribed medicines, such as natural products, could be beneficial. Delayed gastric emptying and impaired gastric accommodation play important roles in the development of FD. Anethole (1-methoxy-4-((E)-propenyl)-benzene), a major component of essential fennel oil, has been used as a flavoring, in alcoholic beverage production and in pharmaceutical formulations for many years. In this study, we examined the effects of anethole on delayed gastric emptying and impaired gastric accommodation in rodents. Oral administration of anethole improved clonidine-induced delayed gastric emptying but did not affect normal gastric emptying in mice. Fennel oil and Anchu-san (a Japanese herbal medicine containing anethole) also restored delayed gastric emptying. Furthermore, oral administration of anethole stimulated gastric accommodation in rats. These results suggest that anethole could be beneficial for the treatment of FD.

Synthesis and biological comparison of enantiomers of mepenzolate bromide, a muscarinic receptor antagonist with bronchodilatory and anti-inflammatory activities

Chronic obstructive pulmonary disease (COPD) is characterized by abnormal inflammatory responses and airflow limitations. We recently proposed that the muscarinic antagonist mepenzolate bromide (mepenzolate) would be therapeutically effective against COPD due to its muscarinic receptor-dependent bronchodilatory activity as well as anti-inflammatory properties. Mepenzolate has an asymmetric carbon atom, thus providing us with the opportunity to synthesize both of its enantiomers ((R)- and (S)-mepenzolate) and to examine their biochemical and pharmacological activities. (R)- or (S)-mepenzolate was synthesized by condensation of benzilic acid with (R)- or (S)-alcohol, respectively, followed by quaternization of the tertiary amine. As predicted by computational simulation, a filter-binding assay in vitro revealed that (R)-mepenzolate showed a higher affinity for the muscarinic M3 receptor than (S)-mepenzolate. In vivo, the bronchodilatory activity of (R)-mepenzolate was superior to that of (S)-mepenzolate, whereas anti-inflammatory activity was indistinguishable between the two enantiomers. We confirmed that each mepenzolate maintained its original stereochemistry in the lung when administered intratracheally. These results suggest that (R)-mepenzolate may have superior properties to (S)-mepenzolate as a drug to treat COPD patients given that the former has more potent bronchodilatory activity than the latter.

Identification of a unique nsaid, fluoro-loxoprofen with gastroprotective activity.

We previously proposed that direct cytotoxicity of NSAIDs due to their membrane permeabilization activity, together with their ability to decrease gastric prostaglandin E(2), contributes to production of gastric lesions. Compared to loxoprofen (LOX), fluoro-loxoprofen (F-LOX) has much lower membrane permeabilization and gastric ulcerogenic activities but similar anti-inflammatory activity. In this study, we examined the mechanism for this low ulcerogenic activity in rats. Compared to LOX, the level of gastric mucosal cell death was lower following administration of F-LOX. However, the gastric level of prostaglandin E(2) was similar in response to treatment with the two NSAIDs. Oral pre-administration of F-LOX conferred protection against the formation of gastric lesions produced by subsequent administration of LOX and orally administered F-LOX resulted in a higher gastric pH value and mucus content. In the presence of a stimulant of gastric acid secretion, the difference in the ulcerogenic activity of F-LOX and LOX was less apparent. Furthermore, an increase in the mucus was observed in gastric cells cultured in the presence of F-LOX in a manner dependent of increase in the cellular level of cAMP. These results suggest that low ulcerogenic activity of F-LOX involves its both low direct cytotoxicity and protective effect against the development of gastric lesions. This protective effect seems to be mediated through an increase in a protective factor (mucus) and a decrease in an aggressive factor (acid).