Imbalance of glutamatergic and GABAergic neurotransmission in audiogenic seizure-susceptible Leucine-rich glioma-inactivated 1 (Lgi1)-mutant rats.

Leucine-rich glioma-inactivated 1 (LGI1) was identified as a causative gene of autosomal dominant lateral temporal lobe epilepsy. We previously reported that Lgi1-mutant rats carrying a missense mutation (L385R) showed audiogenic seizure-susceptibility. To explore the pathophysiological mechanisms underlying Lgi1-related epilepsy, we evaluated changes in glutamate and GABA release in Lgi1-mutant rats. Acoustic priming (AP) for audiogenic seizure-susceptibility was performed by applying intense sound stimulation (130 dB, 10 kHz, 5 min) on postnatal day 16. Extracellular glutamate and GABA levels in the hippocampus CA1 region were evaluated at 8 weeks of age, using in vivo microdialysis techniques. Under naïve conditions without AP, glutamate and GABA release evoked by high-K+ depolarization was more prominent in Lgi1-mutant than in wild-type (WT) rats. The AP treatment on day 16 significantly increased basal glutamate levels and depolarization-induced glutamate release both in Lgi1-mutant and WT rats, yielding greater depolarization-induced glutamate release in Lgi1-mutant rats. On the other hand, the AP treatment enhanced depolarization-induced GABA release only in WT rats, and not in Lgi1-mutant rats, illustrating reduced GABAergic neurotransmission in primed Lgi1-mutant rats. The present results suggest that enhanced glutamatergic and reduced GABAergic neurotransmission are involved in the audiogenic seizure-susceptibility associated with Lgi1-mutation.

An efficient CRISPR interference-based prediction method for synergistic/additive effects of novel combinations of anti-tuberculosis drugs.

Tuberculosis (TB) is treated by chemotherapy with multiple anti-TB drugs for a long period, spanning 6 months even in a standard course. In perspective, to prevent the emergence of antimicrobial resistance, novel drugs that act synergistically or additively in combination with major anti-TB drugs and, if possible, shorten the duration of TB therapy are needed. However, their combinatorial effect cannot be predicted until the lead identification phase of the drug development. Clustered regularly interspaced short palindromic repeats interference (CRISPRi) is a powerful genetic tool that enables high-throughput screening of novel drug targets. The development of anti-TB drugs promises to be accelerated by CRISPRi. This study determined whether CRISPRi could be applicable for predictive screening of the combinatorial effect between major anti-TB drugs and an inhibitor of a novel target. In the checkerboard assay, isoniazid killed Mycobacterium smegmatis synergistically or additively in combinations with rifampicin or ethambutol, respectively. The susceptibility to rifampicin and ethambutol was increased by knockdown of inhA, which encodes a target molecule of isoniazid. Additionally, knockdown of rpoB, which encodes a target molecule of rifampicin, increased the susceptibility to isoniazid and ethambutol, which act synergistically with rifampicin in the checkerboard assay. Moreover, CRISPRi could successfully predict the synergistic action of cyclomarin A, a novel TB drug candidate, with isoniazid or rifampicin. These results demonstrate that CRISPRi is a useful tool not only for drug target exploration but also for screening the combinatorial effects of novel combinations of anti-TB drugs. This study provides a rationale for anti-TB drug development using CRISPRi.

Down syndrome cell adhesion molecule like-1 (DSCAML1) links the GABA system and seizure susceptibility.

The Ihara epileptic rat (IER) is a mutant model with limbic-like seizures whose pathology and causative gene remain elusive. In this report, via linkage analysis, we identified Down syndrome cell adhesion molecule-like 1(Dscaml1) as the responsible gene for IER. A single base mutation in Dscaml1 causes abnormal splicing, leading to lack of DSCAML1. IERs have enhanced seizure susceptibility and accelerated kindling establishment. Furthermore, GABAergic neurons are severely reduced in the entorhinal cortex (ECx) of these animals. Voltage-sensitive dye imaging that directly presents the excitation status of brain slices revealed abnormally persistent excitability in IER ECx. This suggests that reduced GABAergic neurons may cause weak sustained entorhinal cortex activations, leading to natural kindling via the perforant path that could cause dentate gyrus hypertrophy and epileptogenesis. Furthermore, we identified a single nucleotide substitution in a human epilepsy that would result in one amino acid change in DSCAML1 (A2105T mutation). The mutant DSCAML1A2105T protein is not presented on the cell surface, losing its homophilic cell adhesion ability. We generated knock-in mice (Dscaml1A2105T) carrying the corresponding mutation and observed reduced GABAergic neurons in the ECx as well as spike-and-wave electrocorticogram. We conclude that DSCAML1 is required for GABAergic neuron placement in the ECx and suppression of seizure susceptibility in rodents. Our findings suggest that mutations in DSCAML1 may affect seizure susceptibility in humans.

Prolyl-hydroxylase inhibitors reconstitute tumor blood vessels in mice.

Tumor blood vessels have leaky and low blood flow properties, which lead to hypoxia and low nutrient levels in the tumor tissue area known as the tumor microenvironment (TME). We reported that the prolyl-hydroxylase (PHD) inhibitor Roxadustat normalized tumor blood vessels, improved tumor tissue perfusion, and re-oxygenated the tumor tissue. Recently, several PHD inhibitors including Roxadustat, Daprodustat, Molidustat, and Vadadustat, were evaluated in clinical trials and approved for treating renal anemia. In this study, we showed that PHD inhibitors reconstituted tumor blood vessels and improved the TME, and some agents exhibited differential effects on tumors in a mouse model.

[Function of synaptic vesicle protein 2A (SV2A) as a novel therapeutic target for epilepsy].

Epilepsy is a chronic neurologic disease characterized by recurrent seizures, affecting nearly 1% of the population. Synaptic vesicle protein 2A (SV2A) is a membrane protein specifically expressed in synaptic vesicles and is now implicated in the pathogenesis of epileptic disorders. This is because 1) Sv2a-knockout mice exhibit severe seizures, 2) SV2A serves as a specific binding site for certain antiepileptics (e.g., levetiracetam and its analogues) and 3) the SV2A expression changes under various epileptic conditions both in animals (e.g., kindling) and humans (e.g., intractable temporal lobe epilepsy and focal cortical dysplasia). Furthermore, it has been shown that a missense mutation in the SV2A gene caused intractable epilepsy, involuntary movements and developmental retardation, indicating a causative role of SV2A dysfunction in epilepsy. In order to explore the mechanism of SV2A in modulating development of epileptogenesis, we recently developed a novel rat model (Sv2aL174Q rat) carrying a missense mutation (Leu174Gln) in the Sv2a gene. These rats were highly susceptible to the kindling development associated with repeated pentylenetetrazole treatments or electrical stimulations of the amygdala. In addition, the Sv2aL174Q mutation specifically impaired depolarization-induced GABA, but not glutamate, release in the hippocampus and amygdala. All this evidence indicates that the SV2A-GABAergic system plays a crucial role in modulating epileptogenesis and encourages discovery research into the novel antiepileptic agents which enhance the function of the SV2A-GABA system.

Therapeutic Role of Synaptic Vesicle Glycoprotein 2A (SV2A) in Modulating Epileptogenesis.

Dysfunction of synaptic neurotransmitter release is closely involved in the pathogenesis of various central nervous system diseases. Synaptic vesicle glycoprotein 2A (SV2A) is a membrane protein specifically expressed in synaptic vesicles and it modulates action potential-dependent neurotransmitter release in the brain. Since 1) SV2A-knockout mice exhibit severe convulsive seizures, 2) SV2A expression in the brain is reportedly altered in various epileptic disorders both in animal models (e.g., kindling and genetic models) and humans (e.g., intractable temporal lobe epilepsy and focal cortical dysplasia) and 3) SV2A serves as a specific binding site for the antiepileptic drug, levetiracetam and its analogues, it is considered that SV2A is involved in the pathogenesis and treatment of epilepsy. In addition, a recent clinical study demonstrated that a missense mutation in the SV2A gene caused intractable epilepsy with involuntary movements and developmental retardation, illustrating a causative role of SV2A dysfunction in epilepsy. Although the functional mechanisms of SV2A in regulating epileptogenesis remain unknown, studies using animals carrying the Sv2a missense mutation showed that the dysfunction of SV2A preferentially disrupts action potential-induced γ-aminiobutyric acid (GABA), but not glutamate, released in the limbic regions (i.e., hippocampus and amygdala) and markedly facilitates kindling epileptogenesis. All these evidences indicate that the SV2A-GABAergic system plays a crucial role in modulating epileptogenesis and encourages research on the novel antiepileptic agents which enhance SV2A function.

Nicotine Elicits Convulsive Seizures by Activating Amygdalar Neurons.

Nicotinic acetylcholine (nACh) receptors are implicated in the pathogenesis of epileptic disorders; however, the mechanisms of nACh receptors in seizure generation remain unknown. Here, we performed behavioral and immunohistochemical studies in mice and rats to clarify the mechanisms underlying nicotine-induced seizures. Treatment of animals with nicotine (1-4 mg/kg, i.p.) produced motor excitement in a dose-dependent manner and elicited convulsive seizures at 3 and 4 mg/kg. The nicotine-induced seizures were abolished by a subtype non-selective nACh antagonist, mecamylamine (MEC). An α7 nACh antagonist, methyllycaconitine, also significantly inhibited nicotine-induced seizures whereas an α4ß2 nACh antagonist, dihydro-ß-erythroidine, affected only weakly. Topographical analysis of Fos protein expression, a biological marker of neural excitation, revealed that a convulsive dose (4 mg/kg) of nicotine region-specifically activated neurons in the piriform cortex, amygdala, medial habenula, paratenial thalamus, anterior hypothalamus and solitary nucleus among 48 brain regions examined, and this was also suppressed by MEC. In addition, electric lesioning of the amygdala, but not the piriform cortex, medial habenula and thalamus, specifically inhibited nicotine-induced seizures. Furthermore, microinjection of nicotine (100 and 300 µg/side) into the amygdala elicited convulsive seizures in a dose-related manner. The present results suggest that nicotine elicits convulsive seizures by activating amygdalar neurons mainly via α7 nACh receptors.

Inhibition of Inwardly Rectifying Potassium (Kir) 4.1 Channels Facilitates Brain-Derived Neurotrophic Factor (BDNF) Expression in Astrocytes.

Inwardly rectifying potassium (Kir) 4.1 channels in astrocytes regulate neuronal excitability by mediating spatial potassium buffering. Although dysfunction of astrocytic Kir4.1 channels is implicated in the development of epileptic seizures, the functional mechanisms of Kir4.1 channels in modulating epileptogenesis remain unknown. We herein evaluated the effects of Kir4.1 inhibition (blockade and knockdown) on expression of brain-derived neurotrophic factor (BDNF), a key modulator of epileptogenesis, in the primary cultures of mouse astrocytes. For blockade of Kir4.1 channels, we tested several antidepressant agents which reportedly bound to and blocked Kir4.1 channels in a subunit-specific manner. Treatment of astrocytes with fluoxetine enhanced BDNF mRNA expression in a concentration-dependent manner and increased the BDNF protein level. Other antidepressants (e.g., sertraline and imipramine) also increased the expression of BDNF mRNA with relative potencies similar to those for inhibition of Kir4.1 channels. In addition, suppression of Kir4.1 expression by the transfection of small interfering RNA (siRNA) targeting Kir4.1 significantly increased the mRNA and protein levels of BDNF. The BDNF induction by Kir4.1 siRNA transfection was suppressed by the MEK1/2 inhibitor U0126, but not by the p38 MAPK inhibitor SB202190 or the JNK inhibitor SP600125. The present results demonstrated that inhibition of Kir4.1 channels facilitates BDNF expression in astrocytes primarily by activating the Ras/Raf/MEK/ERK pathway, which may be linked to the development of epilepsy and other neuropsychiatric disorders.

Nicotine evokes kinetic tremor by activating the inferior olive via α7 nicotinic acetylcholine receptors.

Nicotinic acetylcholine (nACh) receptors are implicated in the pathogenesis of movement disorders (e.g., tremor) and epilepsy. Here, we performed behavioral and immunohistochemical studies using mice and rats to elucidate the mechanisms underlying nicotine-induced tremor. Treatments of animals with nicotine (0.5-2mg/kg, i.p.) elicited kinetic tremor, which was completely suppressed by the nACh receptor antagonist mecamylamine (MEC). The specific α7 nACh receptor antagonist methyllycaconitine (MLA) also inhibited nicotine-induced tremor, whereas the α4ß2 nACh antagonist dihydro-ß-erythroidine (DHßE) or the peripheral α3ß4 nACh antagonist hexamethonium showed no effects. Mapping analysis of Fos protein expression, a biological marker of neural excitation, revealed that a tremorgenic dose (1mg/kg) of nicotine region-specifically elevated Fos expression in the piriform cortex (PirC), medial habenula, solitary nucleus and inferior olive (IO) among 44 brain regions examined. In addition, similarly to the tremor responses, nicotine-induced Fos expression in the PirC and IO was selectively antagonized by MLA, but not by DHßE. Furthermore, an electrical lesioning of the IO, but not the PirC, significantly suppressed the induction of nicotine tremor. The present results suggest that nicotine elicits kinetic tremor in rodents by activating the IO neurons via α7 nACh receptors.

A Missense Mutation of the Gene Encoding Synaptic Vesicle Glycoprotein 2A (SV2A) Confers Seizure Susceptibility by Disrupting Amygdalar Synaptic GABA Release.

Synaptic vesicle glycoprotein 2A (SV2A) is specifically expressed in the membranes of synaptic vesicles and modulates action potential-dependent neurotransmitter release. To explore the role of SV2A in the pathogenesis of epileptic disorders, we recently generated a novel rat model (Sv2a(L174Q) rat) carrying a missense mutation of the Sv2a gene and showed that the Sv2a(L174Q) rats were hypersensitive to kindling development (Tokudome et al., 2016). Here, we further conducted behavioral and neurochemical studies to clarify the pathophysiological mechanisms underlying the seizure vulnerability in Sv2a(L174Q) rats. Sv2a(L174Q) rats were highly susceptible to pentylenetetrazole (PTZ)-induced seizures, yielding a significantly higher seizure scores and seizure incidence than the control animals. Brain mapping analysis of Fos expression, a biological marker of neural excitation, revealed that the seizure threshold level of PTZ region-specifically elevated Fos expression in the amygdala in Sv2a(L174Q) rats. In vivo microdialysis study showed that the Sv2a(L174Q) mutation preferentially reduced high K(+) (depolarization)-evoked GABA release, but not glutamate release, in the amygdala. In addition, specific control of GABA release by SV2A was supported by its predominant expression in GABAergic neurons, which were co-stained with antibodies against SV2A and glutamate decarboxylase 1. The present results suggest that dysfunction of SV2A by the missense mutation elevates seizure susceptibility in rats by preferentially disrupting synaptic GABA release in the amygdala, illustrating the crucial role of amygdalar SV2A-GABAergic system in epileptogenesis.

Synaptic vesicle glycoprotein 2A (SV2A) regulates kindling epileptogenesis via GABAergic neurotransmission.

Synaptic vesicle glycoprotein 2A (SV2A) is a prototype synaptic vesicle protein regulating action potential-dependent neurotransmitters release. SV2A also serves as a specific binding site for certain antiepileptics and is implicated in the treatment of epilepsy. Here, to elucidate the role of SV2A in modulating epileptogenesis, we generated a novel rat model (Sv2a(L174Q) rat) carrying a Sv2a-targeted missense mutation (L174Q) and analyzed its susceptibilities to kindling development. Although animals homozygous for the Sv2a(L174Q) mutation exhibited normal appearance and development, they are susceptible to pentylenetetrazole (PTZ) seizures. In addition, development of kindling associated with repeated PTZ treatments or focal stimulation of the amygdala was markedly facilitated by the Sv2a(L174Q) mutation. Neurochemical studies revealed that the Sv2a(L174Q) mutation specifically reduced depolarization-induced GABA, but not glutamate, release in the hippocampus without affecting basal release or the SV2A expression level in GABAergic neurons. In addition, the Sv2a(L174Q) mutation selectively reduced the synaptotagmin1 (Syt1) level among the exocytosis-related proteins examined. The present results demonstrate that dysfunction of SV2A due to the Sv2a(L174Q) mutation impairs the synaptic GABA release by reducing the Syt1 level and facilitates the kindling development, illustrating the crucial role of SV2A-GABA system in modulating kindling epileptogenesis.

New insight into the therapeutic role of the serotonergic system in Parkinson's disease.

Parkinson's disease (PD) is a common, late-onset neurodegenerative disorder that shows progressive extrapyramidal motor disorders (e.g., bradykinesia, resting tremors, muscle rigidity and postural instability) and various non-motor symptoms (e.g., cognitive impairment, mood disorders, autonomic dysfunction and sleep disorders). While dopaminergic agents such as L-3,4-dihydroxyphenylalanine (L-DOPA) and dopamine D2 agonists are widely used for the treatment of PD, there is still high clinical unmet need for novel medications that overcome the limitations of current therapies. Evidence is now accumulating that the serotonergic nervous system is involved in the pathophysiological basis of PD and can provide benefits in the treatment of PD through its diverse functions. Among 5-HT receptor subtypes, 5-HT1A, 5-HT2, 5-HT3 and 5-HT6 receptors play an important role in modulating extrapyramidal motor disorders. In addition, 5-HT1A, 5-HT2, 5-HT3, 5-HT4 and 5-HT6 receptors are implicated in modulation of cognitive impairment, mood disorders (e.g., depression and anxiety) and/or psychosis, which are frequently observed in patients with PD. Specifically, stimulation of 5-HT1A receptors seems to be effective for multiple PD symptoms including parkinsonism, L-DOPA-induced dyskinesia, cognitive impairment, mood disorders and neurodegeneration of dopamine neurons. Blockade of 5-HT2 receptors is also likely to improve parkinsonism, depressive mood and cognitive impairment. In addition, it was recently demonstrated that 5-HT2A inverse agonists can alleviate PD psychosis. All these findings emphasize the therapeutic roles of the serotonergic system in PD and stimulate new insight into novel treatments by modulating 5-HT1A and 5-HT2 receptors.

The role of gastroesophageal reflux in relation to symptom onset in patients with proton pump inhibitor-refractory nonerosive reflux disease accompanied by an underlying esophageal motor disorder.

BACKGROUND: The symptom improvement rate is low with proton pump inhibitors (PPIs) in nonerosive reflux disease (NERD). The underlying pathogenic mechanism is complex. Esophageal motility disorders (EMDs) are thought to be a factor, but their prevalence, type, symptoms and the role played by gastroesophageal reflux (GER) in symptom onset have not been fully investigated. AIM: To investigate the role of GER in symptom onset in PPI-refractory NERD patients with EMDs. METHODS: This study comprised 76 patients with PPI-refractory NERD. Manometry was performed during PPI treatment and patients were divided into an EMD group and normal motility (non-EMD) group. Then, multichannel intraluminal impedance-pH monitoring was performed and medical interviews were conducted. RESULTS: Nineteen patients (25%) had an EMD. Data were compared between 17 patients, excluding 2 with achalasia and 57 non-EMD patients. No significant differences were observed between groups in 24-hour intraesophageal pH <4 holding time (HT), mean number of GER episodes or mean number of proximal reflux episodes. The reflux-related symptom index (≥50%) showed a relationship between reflux and symptoms in 70.5% of EMD patients and 75% of non-EMD patients. In the EMD group, the score for FSSG (Frequency Scale for the Symptoms of GERD) question (Q)10 was significantly correlated with the number of GER episodes (r = 0.58, p = 0.02) and the number of proximal reflux episodes (r = 0.63, p = 0.02). In addition, the score for Q9 tended to be correlated with the number of GER episodes (r = 0.44, p = 0.06). CONCLUSION: Our results suggest that some PPI-refractory NERD patients have EMDs, and that GER plays a role in symptom onset.

Preferential suppression of limbic Fos expression by intermittent hypoxia in obese diabetic mice.

Sleep apnea (SA) causes not only sleep disturbances, but also neurocognitive impairments and/or psychoemotional disorders. Here, we studied the effects of intermittent hypoxia (IH) on forebrain Fos expression using obese diabetic db/db mice to explore the pathophysiological alterations in neural activities and the brain regions related to SA syndrome. Male db/db mice were exposed to IH stimuli (repetitive 6-min cycles of 1min with 5% oxygen followed by 5min with 21% oxygen) for 8h (80 cycles) per day or normoxic condition (control group) for 14 days. Fos protein expression was immunohistochemically examined a day after the last IH exposure. Mapping analysis revealed a significant reduction of Fos expression by IH in limbic and paralimbic structures, including the cingulate and piriform cortices, the core part of the nucleus accumbens and most parts of the amygdala (i.e., the basolateral and basomedial amygdaloid nuclei, cortical amygdaloid area and medial amygdaloid nucleus). In the brain stem regions, Fos expression was region-specifically reduced in the ventral tegmental area while other regions including the striatum, thalamus and hypothalamus, were relatively resistant against IH. In addition, db/db mice exposed to IH showed a trend of sedative and/or depressive behavioral signs in the open field and forced swim tests. The present results illustrate that SA in the obese diabetic model causes neural suppression preferentially in the limbic and paralimbic regions, which may be related to the neuropsychological disturbances associated with SA.

Pathophysiological roles of serotonergic system in regulating extrapyramidal motor functions.

The serotonergic nervous system plays crucial roles in regulating psycho-emotional, cognitive, sensori-motor and autonomic functions. It is now known that multiple serotonin (5-hydroxytryptamine; 5-HT) receptors regulate extrapyramidal motor functions, which are implicated in pathogenesis and/or treatment of various neurological disorders (e.g., Parkinson's disease and drug-induced extrapyramidal motor deficits). Specifically, antagonism of 5-HT2A/2C receptors alleviates antipsychotic-induced extrapyramidal side effects (EPS) by relieving the 5-HT2A/2C receptor-mediated inhibition of nigral dopaminergic neuron activity and striatal dopamine release. Indeed, many of the second generation antipsychotics (e.g., risperidone, perospirone and olanzapine) commonly possess potent 5-HT2A/2C blocking actions which contribute to their atypical antipsychotic property. In addition, activation of 5-HT1A receptors also improves antipsychotic-induced EPS and motor disabilities in animal models of Parkinson's disease. Microinjection studies revealed that stimulation of postsynaptic 5-HT1A receptors in the striatum or motor cortex plays an important role in the antiparkinsonian actions. Furthermore, recent studies demonstrated that antagonism of 5-HT3 and 5-HT6 receptors alleviates extrapyramidal motor disorders while 5-HT4, 5-HT5, and 5-HT7 receptors are mostly inactive. These results encourage drug discovery research into new 5-HT receptor ligands that could improve current therapies for extrapyramidal motor disorders.

Comparison of the effect of a single dose of omeprazole or lansoprazole on intragastric pH in Japanese participants: a two-way crossover study.

BACKGROUND: It is known that the pharmacokinetic profile of proton pump inhibitors (PPIs) after postprandial administration may differ among PPIs. The purpose of this study was to compare the inhibitory effects of gastric acid secretion by PPIs administered after a meal, based on a 24-hour intragastric pH monitoring. METHODS: Ten healthy men who provided written informed consent participated in the study. They were given a 20-mg omeprazole tablet and a 30-mg lansoprazole orally dispersing tablet in a two-way crossover manner. At baseline, the anti-HP-IgG antibody levels in blood and the pepsinogen (PG) I/II ratio were measured. Participants were given a standardized meal and 200 mL of water at 9:30 am, 13:30 pm, and 18.30 pm. Participants took the PPI after breakfast. RESULTS: Two of the ten participants tested positive for Helicobacter pylori infection. The PG I/II ratio indicated negative gastric atrophy in all the participants. The percentage 24-hour intragastric pH > 4 holding times (median, range) with omeprazole and lansoprazole were 29.3, 19.3-50.0% and 27.8, 13.0-42.3%, respectively, which shows that with the administration of omeprazole, the pH was maintained at >4 for a longer period (p < 0.05). Each median intragastric pH value per hour at 3, 17, and 18 hours after a dose of omeprazole was significantly higher than that of lansoprazole (p < 0.05). CONCLUSION: Compared with lansoprazole, a single postprandial dose of omeprazole showed a more rapid and sustained acid-inhibitory effect.

Inhibition of gastric perception of mild distention by omeprazole in volunteers.

AIM: To evaluate the effects of omeprazole on gastric mechanosensitivity in humans. METHODS: A double lumen polyvinyl tube with a plastic bag was introduced into the stomach of healthy volunteers under fluorography and connected to a barostat device. Subjects were then positioned so they were sitting comfortably, and the minimal distending pressure (MDP) was determined after a 30-min adaptation period. Isobaric distensions were performed in stepwise increments of 2 mmHg (2 min each) starting from the MDP. Subjects were instructed to score feelings at the end of every step using a graphic rating scale: 0, no perception; 1, weak/vague; 2, weak but significant; 3, moderate/vague; 4, moderate but significant; 5, severe discomfort; and 6, unbearable pain. After this first test, subjects received omeprazole (20 mg, after dinner) once daily for 1 wk. A second test was performed on the last day of treatment. RESULTS: No adverse effects were observed. Mean MDP before and after treatment was 6.3 ± 0.3 mmHg and 6.2 ± 0.5 mmHg, respectively. One subject before and 2 after treatment did not reach a score of 6 at the maximum bag volume of 750 mL. After omeprazole, there was a significant increase in the distension pressure required to reach scores of 1 (P = 0.019) and 2 (P = 0.017) as compared to baseline. There were no changes in pressure required to reach the other scores after treatment. Two subjects before and one after omeprazole rated their abdominal feeling < 1 at MDP, and mean (± SE) abdominal discomfort scores at MDP were 0.13 ± 0.09 and 0.04 ± 0.04, respectively. Mean scores induced by each MDP + 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 (mmHg) were 1.1 ± 0.3, 2.0 ± 0.4, 2.9 ± 0.5, 3.3 ± 0.4, 4.6 ± 0.3, 5.2 ± 0.3, 5.5 ± 0.2, 5.5 ± 0.3, 5.7 ± 0.3, and 5.4, respectively. After omeprazole, abdominal feeling scores for the same incremental pressures over MDP were 0.3 ± 0.1, 0.8 ± 0.1, 2.0 ± 0.4, 2.8 ± 0.4, 3.8 ± 0.4, 4.6 ± 0.4, 4.9 ± 0.3, 5.4 ± 0.4, 5.2 ± 0.6, and 5.0 ± 1.0, respectively. A significant decrease in feeling score was observed at intrabag pressures of MDP + 2 mmHg (P = 0.028) and + 4 mmHg (P = 0.013), respectively, after omeprazole. No significant score changes were observed at pressures ≥ MDP + 6 mmHg. CONCLUSION: Although the precise mechanisms are undetermined, the present study demonstrated that omeprazole decreases mechanosensitivity to mild gastric distension.

Efficacy of endoluminal gastroplication in Japanese patients with proton pump inhibitor-resistant, non-erosive esophagitis.

AIM: To evaluate the efficacy, safety, and long-term outcomes of endoluminal gastroplication (ELGP) in patients with proton pump inhibitor (PPI)-resistant, non-erosive reflux disease (NERD). METHODS: The subjects were NERD patients, diagnosed by upper endoscopy before PPI use, who had symptoms such as heartburn or reflux sensations two or more times a week even after 8 wk of full-dose PPI treatment. Prior to ELGP, while continuing full-dose PPI medication, patients' symptoms and quality of life (QOL) were assessed using the questionnaire for the diagnosis of reflux disease, the frequency scale for symptoms of gastro-esophageal reflux disease (FSSG), gastrointestinal symptoms rating scale, a 36-item short-form. In addition, 24-h esophageal pH monitoring or 24-h intraesophageal pH/impedance (MII-pH) monitoring was performed. The Bard EndoCinch(TM) was used for ELGP, and 2 or 3 plications were made. After ELGP, all acid reducers were temporarily discontinued, and medication was resumed depending on the development and severity of symptoms. Three mo after ELGP, symptoms, QOL, pH or MII-pH monitoring, number of plications, and PPI medication were evaluated. Further, symptoms, number of plications, and PPI medication were evaluated 12 mo after ELGP to investigate long-term effects. RESULTS: The mean FSSG score decreased significantly from before ELGP to 3 and 12 mo after ELGP (19.1 ± 10.5 to 10.3 ± 7.4 and 9.3 ± 9.9, P < 0.05, respectively). The total number of plications decreased gradually at 3 and 12 mo after ELGP (2.4 ± 0.8 to 1.2 ± 0.8 and 0.8 ± 1.0, P < 0.05, respectively). The FSSG scores in cases with no remaining plications and in cases with one or more remaining plications were 4.4 and 2.7, respectively, after 3 mo, and 2.0 and 2.8, respectively, after 12 mo, showing no correlation to plication loss. On pH monitoring, there was no difference in the percent time pH < 4 from before ELGP to 3 mo after. Impedance monitoring revealed no changes in the number of reflux episodes or the symptom index for reflux events from before ELGP to 3 mo after, but the symptom sensitivity index decreased significantly 3 mo after ELGP (16.1 ± 12.9 to 3.9 ± 8.3, P < 0.01). At 3 mo after ELGP, 6 patients (31.6%) had reduced their PPI medication by 50% or more, and 11 patients (57.9%) were able to discontinue PPI medication altogether. After 12 mo, 3 patients (16.7%) were able to reduce the amount of PPI medication by 50% or more, and 12 patients (66.7%) were able to discontinue PPI medication altogether. A high percentage of cases with remaining plications had discontinued PPIs medication after 3 mo, but there was no difference after 12 mo. No serious complications were observed in this study. CONCLUSION: ELGP was safe, resulted in significant improvement in subjective symptoms, and allowed less medication to be used over the long term in patients with PPI-refractory NERD.

Usefulness of a slow nutrient drinking test for evaluating gastric perception and accommodation.

BACKGROUND/AIM: An implication of the drinking test for gastric function is controversial. We evaluated the usefulness of a nutrient drinking test for examining gastric function by comparing it with a gastric barostat study. METHODS: We investigated perceived pressure of an intragastric bag with stepwise distension and postprandial peak gastric volume (accommodation volume) with a consistent pressure after drinking a liquid meal (200 ml, 300 kcal) in 18 volunteers. Drinking a similar liquid meal on a different day at a continual rate of 15 ml/min was performed to score satiety and bloated sensations at 5-min intervals. An additional 10 volunteers performed the drinking test before and after administration of mosapride citrate or a placebo in a double-blind crossover study. RESULTS: Pressure to induce severe discomfort correlated positively with maximum satiety volume in the drinking test (r = 0.60, p = 0.02). Accommodation volume in the barostat study showed a significant correlation (r = 0.59, p = 0.03) with threshold volume to induce bloating in the drinking test. Mosapride tended to increase the volume inducing the first bloated sensation as compared to the placebo. CONCLUSION: The present drinking test may be useful for evaluating the threshold to induce severe discomfort and accommodation volume.

Rebamipide suppresses TLR-TBK1 signaling pathway resulting in regulating IRF3/7 and IFN-α/ß reduction.

TANK-binding kinase 1 (TBK1) regulates the interferon regulatory factor (IRF) 3 and IRF7 activation pathways by double strand RNA (dsRNA) via Toll-like receptor (TLR) 3 and by lipopolysaccharide (LPS) via TLR4. Rebamipide is useful for treating inflammatory bowel disease (IBD). Although IBD is associated with nuclear factor-κB (NF-κB), any association with the TBK1-IRF pathway remains unknown. How rebamipide affects the TBK1-IRF pathway is also unclear. We analyzed the relationship between IBD (particularly ulcerative colitis; UC) and the TLR-TBK1-IRF3/7 pathway using human colon tissue, a murine model of colitis and human colonic epithelial cells. Inflamed colonic mucosa over-expressed TKB1, NAP1, IRF3, and IRF7 mRNA compared with normal mucosa. TBK1 was mainly expressed in inflammatory epithelial cells of UC patients. The expression of TBK1, IRF3, IRF7, IFN-α and IFN-ß mRNA was suppressed in mice given oral dextran sulfate-sodium (DSS) and daily rectal rebamipide compared with mice given only DSS. Rebamipide reduced the expression of TBK1, IRF3 and IRF7 mRNA induced by LPS/dsRNA, but not of NF-κB mRNA in colonic epithelial cells. Rebamipide might suppress the TLR-TBK1 pathway, resulting in IRF3/7-induction of IFN-α/ß and inflammatory factors. TBK1 is important in the induction of inflammation in patients with UC. If rebamipide represses the TLR-TBK1 pathway, then rectal administration should suppress inflammation of the colonic mucosa in patients with UC.