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Background: The incidence and mortality rates of colorectal cancer (CRC) has been reported to be strongly associated to sex/gender difference. CRC shows sexual dimorphism, and sex hormones have been shown to affect the tumor immune microenvironment. This study aimed to investigate location-dependent sex differences in tumorigenic molecular characteristics in patients with colorectal tumors, including adenoma and CRC. Methods: A total of 231 participants, including 138 patients with CRC, 55 patients with colorectal adenoma, and 38 healthy controls, were recruited between 2015 and 2021 at Seoul National University Bundang Hospital. All patients underwent colonoscopy and acquired tumor lesion samples were further analyzed for programmed death-ligand 1 (PD-L1), epidermal growth factor receptor (EGFR) expression, deficient mismatch repair (dMMR), and microsatellite instability (MSI) status. This study was registered with ClinicalTrial.gov, number NCT05638542. Results: The average of combined positive score (CPS) was higher in serrated lesions and polyps (lesions/polyps) compared to conventional adenomas (5.73 and 1.41, respectively, P < 0.001). No significant correlation was found between sex and PD-L1 expression within the groups, regardless of histopathological diagnosis. In multivariate analysis where each sex was further stratified by tumor location due to their interaction in CRC, PD-L1 expression was inversely correlated with males having proximal CRC with a CPS cutoff of 1 (Odds ratio (OR) 0.28, P = 0.034). Females with proximal CRC showed a significant association with dMMR/MSI-high (OR 14.93, P = 0.032) and high EGFR expression (OR 4.17, P = 0.017). Conclusion: Sex and tumor location influenced molecular features such as PD-L1, MMR/MSI status and EGFR expression in CRC, suggesting a possible underlying mechanism of sex-specific colorectal carcinogenesis. [ABSTRACT FROM AUTHOR]

In Mg2+-free aCSF, bursting discharges were induced in the posterior telencephalon of zebrafish following an electrical stimulation of the anterior telencephalon. The bursting discharges were partially reduced by CNQX (10μM), an AMPA receptor antagonist, and the remaining activity was completely blocked by an additional treatment of APV (50μM), an NMDA receptor antagonist. Long-term potentiation that lasted more than 1h was also induced after 20min of perfusion with KCl (10mM). The degree of KCl-induced long-term potentiation (K-LTP) was reduced when a concomitant electrical stimulation was not delivered during a KCl perfusion. K-LTP was blocked by APV (50μM) but not by nifedipine (10μM), an L-type Ca2+ channel blocker. Furthermore, K-LTP was not induced in the presence of a broad spectrum inhibitor for protein kinases, H-7 (10μM). These results suggest that NMDA receptors and protein kinases play important roles in the synaptic plasticity of the zebrafish brain. [Copyright &y& Elsevier]

The distribution of GABA-containing neurons was studied in the brain of the adult zebrafish by Nissl staining and immunohistochemistry. GABA immunoreactivity (GABA-IR) was demonstrated in parts of the brain such as olfactory bulb (OB), telencephalon, tectum stratum, and in the hypothalamus. GABA-IR appeared in the area where Nissl-stained cell bodies were abundant. The internal cellular layer of the OB was most densely stained by Nissl staining, and also showed a high level of GABA-IR. The telencephalon and the hypothalamus revealed a similar pattern to the OB in terms of Nissl staining and GABA-IR. However, the distribution and shape of stained cells of the tectum stratum were distinct from those in other regions: Nissl-stained neurons were ubiquitously present throughout all cellular layers including the stratum griseum centrale, the stratum album centrale (SAC), and the stratum periventriculare (SP). However, GABA-IR was weakly expressed in a limited number of neurons only in the SAC and SP. Whether GABA serves as an inhibitory neurotransmitter was also tested in the isolated telencephalon preparation by using extracellular field potential recordings. The synaptic activity recorded in the posterior dorsal telencephalon in response to the electrical stimulation of the anterior dorsal telencephalon was increased in the presence of the GABAA receptor antagonist, BMI, suggesting an inhibitory role for GABA-immunoreactive neurons in the adult brain of the zebrafish. [Copyright &y& Elsevier]

Background: Failure of second or third‐line eradication treatment against Helicobacter pylori (H. pylori) is principally caused by antimicrobial resistance and reduced treatment adherence. Aims: To evaluate the efficacy and safety of culture‐based rescue eradication treatments in patients who have previously experienced failed eradication treatment. Methods: Patients who had persistent H. pylori infection following at least one eradication treatment were recommended to undergo culture analysis to determine the minimal inhibitory concentrations of various antimicrobials via endoscopic resection. Consenting patients were assigned one of four therapeutic treatments based on an algorithm determined by antimicrobial resistance. These treatments consisted of 7 or 14‐day administration of clarithromycin‐containing proton pump inhibitor (PPI) triple therapy; esomeprazole, moxifloxacin, and amoxicillin (MEA) therapy; esomeprazole, bismuth, metronidazole, and tetracycline (quadruple) therapy; or lansoprazole, rifabutin, and amoxicillin (RLA) therapy. Eradication efficacy, adherence, and adverse events were assessed aside clinical outcomes. Results: A total of 132 patients were enrolled, with 84 patients completing the study. The overall resistance rates to amoxicillin, clarithromycin, metronidazole, and moxifloxacin were 13.1%, 83.3%, 47.6%, and 71.4%, respectively. The patients were allocated to the PPI triple (n = 11), MEA (n = 15), quadruple (n = 53), or RLA triple (n = 5) therapy group. The eradication rates in the intention‐to‐treat and per‐protocol analyses were 90.5% (76 of 84 patients) and 93.8% (76 of 81 patients), respectively. Nausea was the most frequent adverse event (25.0%). Conclusions: As a rescue therapy, culture‐based susceptibility‐guided eradication treatment was both effective and safe, even for patients exhibiting high antimicrobial resistance. [ABSTRACT FROM AUTHOR]

Background/Aims: Favorable outcomes of potassium-competitive acid blocker (PCAB)-containing eradication therapy have been reported. In fact, tegoprazan, a recently developed PCAB, was presumed to show good eradication efficacy even for resistant Helicobacter pylori. We aimed to investigate the anti-H. pylori efficacy of tegoprazan compared with that of vonoprazan. Methods: A total of 220 resistant clinical H. pylori isolates were utilized. The anti-H. pylori efficacy of PCABs was determined by evaluating the minimum inhibitory concentrations (MICs) of clarithromycin, fluoroquinolone, metronidazole, and amoxicillin in combination with vonoprazan or tegoprazan by the agar dilution method. The impact of the mutations responsible for resistance development, such as 23S rRNA, gyrA, rdxA, frxA, and pbp1 mutations, was also analyzed. Results: H. pylori growth was significantly inhibited in a medium containing 1 μg/mL clarithromycin with tegoprazan (128 μg/mL). The MICs of clarithromycin (46.3%), fluoroquinolone (46.7%), metronidazole (55.6%), and amoxicillin (34.5%) against resistant H. pylori isolates improved after tegoprazan administration. Tegoprazan demonstrated more frequent susceptibility acquisition with metronidazole than with vonoprazan (20.6% vs 4.7%, p=0.014). However, there were no significant differences depending on the mutational status of each antimicrobial agent. Conclusions: Tegoprazan administration may improve the susceptibility of antimicrobial-resistant H. pylori, independent of acid suppression. [ABSTRACT FROM AUTHOR]

The composition of the gut microbiota is influenced by sex hormones and colorectal cancer (CRC). Previously, we reported that 17β-estradiol (E2) inhibits azoxymethane/dextran sulfate sodium (AOM/DSS)-induced tumorigenesis in male mice. Here, we investigated whether the composition of the gut microbiota is different between male and female, and is regulated by estrogen as a secondary outcome of previous studies. We established four groups of mice based on the sex and estrogen status [ovariectomized (OVX) female and E2-treated male]. Additionally, three groups of males were established by treating them with AOM/DSS, and E2, after subjecting them to AOM/DSS treatment. The mice were sacrificed at 21 weeks old. The composition of the gut microbiota was analyzed using 16S rRNA metagenomics sequencing. We observed a significant increase in the microbial diversity (Chao1 index) in females, males supplemented with E2, and males treated with AOM/DSS/E2 compared with normal males. In normal physiological condition, sex difference and E2 treatment did not affect the ratio of Firmicutes/Bacteroidetes (F/B). However, in AOM/DSS-treated male mice, E2 supplementation showed significantly lower level of the F/B ratio. The ratio of commensal bacteria to opportunistic pathogens was higher in females and E2-treated males compared to normal males and females subjected to OVX. Unexpectedly, this ratio was higher in the AOM/DSS group than that determined in other males and the AOM/DSS/E2 group. Our findings suggest that estrogen alters the gut microbiota in ICR (CrljOri:CD1) mice, particularly AOM/DSS-treated males, by decreasing the F/B ratio and changing Shannon and Simpson index by supply of estrogen. This highlights another possibility that estrogen could cause changes in the gut microbiota, thereby reducing the risk of developing CRC. [ABSTRACT FROM AUTHOR]

Background and Aim: Failure of bismuth quadruple therapy for Helicobacter pylori eradication is frequently observed. To increase the eradication rate, comprehensive analyses need to be performed regarding risk factors of bismuth quadruple therapy failure based on complete standard culture and antimicrobial susceptibility testing results. Methods: Patients with history of failed first therapy who had H. pylori colonies isolated from culture and successful minimum inhibitory concentration (MIC) test were enrolled. Esomeprazole, bismuth, metronidazole, and tetracycline (quadruple) therapies for 7 or 14 days were given. Eradication rate, treatment compliance, adverse events, and risk factors for the failure of bismuth quadruple therapy were analyzed. Results: A total 54 patients were enrolled. Overall eradication rate in the present study was 88.8%. The eradication rate for cases with metronidazole resistance such as MIC 8–16 μg/mL or 16–32 μg/mL was 92.8% (13/14). For cases with high level metronidazole resistance (MIC > 32 μg/mL), the eradication rate was only 60% (6/10). Multivariate analysis regarding compliance, treatment duration, age > 60, three kinds of metronidazole MICs, tetracycline MIC > 4 μg/mL, adverse events and any other parameters, "metronidazole resistance, high level (MIC > 32 μg/mL)" was the only independent risk factor for eradication failure (P = 0.007). Conclusion: For cases with metronidazole resistance at MIC > 32 μg/mL, rescue therapy other than bismuth‐containing quadruple therapy is needed. [ABSTRACT FROM AUTHOR]

Background/Aims: A high-fat diet (HFD) can cause intestinal inflammation and alter the gut microbiota; probiotics, however, are known to have anti-inflammatory effects. This study aimed to investigate the response of rat colon to HFD and the effect of Clostridium butyricum on HFD-induced intestinal inflammation and production of short-chain fatty acids (SCFAs) according to sex. Methods: Male and female 6-week-old Fischer-344 rats were fed a chow diet or HFD for 8 weeks, and Biovita or three different concentrations of C. butyricum were orally gavaged. The levels of tight junction proteins (TJPs), inflammatory markers in the ascending colonic mucosa, and bile acids (BAs) and SCFAs in stool were measured. Results: HFD significantly increased the histological inflammation scores and fat proportions. Fecal BA levels were higher in the HFD group than in the control group, with a more prominent increase in deoxycholic acid/cholic acid after probiotics administration in females; however, no statistically significant differences were observed. TJPs showed an opposite response to HFD depending on sex, and tended to increase and decrease after HFD in males and females, respectively. The HFD-reduced TJPs were recovered by probiotics, with some statistical significance in females. HFD-decreased butyric acid in stools appeared to be recovered by probiotics in males, but not in females. The expression of inflammatory markers (TNF-α) was increased by HFD in males and decreased with medium-concentration probiotic supplementation. The opposite was observed in females. MPO was increased by HFD in both sexes and decreased by probiotic supplementation. Conclusions: The probiotic C. butyricum improved indicators of HFD-induced colonic inflammation such as levels of inflammatory markers and increased the production of SCFAs and the expression of TJPs. These effects tended to be more pronounced in male rats, showing sex difference. [ABSTRACT FROM AUTHOR]

The colonic response to stress is greater in female rats than in male rats. The aim of this study was to evaluate the effect of probiotics in the repeated water avoidance stress (rWAS)-induced colonic microinflammation model of Wistar rats in a sex-specific manner. The three groups (no-stress, WAS, and WAS with probiotics) were exposed to r-WAS for 1 h daily for 10 days, and Lactobacillus farciminis was administered by oral gavage for 10 days to animals in the probiotics group. The visceromotor response (VMR) to colorectal distension (CRD) was assessed using a barostat and noninvasive manometry before and after WAS exposure. Immunohistochemistry for mast cells and real-time polymerase chain reaction (RT-PCR) for detection of mucosal cytokines were performed using distal colon tissue after the animals were sacrificed. Significant reduction of VMR to CRD (visceral analgesia) was observed at 60 mmHg in the female WAS group (P = 0.045), but not in males. In addition, the female WAS with probiotics group showed a significantly lower colonic mucosal mast cell count in comparison to the female WAS group (P = 0.013), but this phenomenon was not observed in the male group. The colonic mucosal mRNA levels of interferon-γ (IFNR), tumor necrosis factor-α (TNFA), interleukin (IL) 6, and IL17 were higher in the female WAS group than in the male WAS group. The mRNA levels of IFNR, TNFA, and IL6 were significantly decreased in WAS females who received probiotics (all P < 0.050). In conclusion, rWAS is induced in a sex-specific manner. A 10-day-long treatment with L. farciminis is an effective therapy for rWAS-induced colonic microinflammation in female rates, but not in male rats. [ABSTRACT FROM AUTHOR]

Background: Failure of Helicobacter pylori (H. pylori) eradication is principally caused by antimicrobial resistance. Nowadays, multidrug resistance could be a major determinant of eradication failure. To assess minimal inhibitory concentration (MIC), antimicrobial resistance rates and trends in H. pylori isolated from patients with upper gastrointestinal disease with long‐term period. Materials and Methods: Patients who had H. pylori colonies isolated from culture were consecutively enrolled during the period of 2003–2022. From each patient, one to ten isolates were collected from culture of mucosal biopsy. MIC test was performed for amoxicillin, clarithromycin, metronidazole, tetracycline, levofloxacin, and moxifloxacin using agar dilution method. Trends in MIC distribution, prevalence of resistances with single and multiple were investigated which were suspected to be related to the failure of empirical H. pylori eradication treatment. Results: From 2003 to 2022, a total of 873 patients were enrolled and 2735 H. pylori isolates were successfully collected. Increase in the primary resistance rate was found in clarithromycin (16.1%–31.0%, p =.022), metronidazole (30.6%–38.1%, p < 0.001), and both of levofloxacin and moxifloxacin (7.3%–35.7%, p < 0.001). The prevalence of multidrug resistance to both clarithromycin and metronidazole (9.2%–37.9%, p < 0.001), clarithromycin and fluoroquinolone (2.8%–41.7%, p < 0.001), and clarithromycin, metronidazole, and fluoroquinolone (1.4%–28.2%, p < 0.001) was found to significantly increase. Conclusions: The prevalence of multiple resistance against H. pylori in Korea is ongoing. Its trend should be considered when establishing an empirical treatment strategy (ClinicalTrials. gov: NCT05247112). [ABSTRACT FROM AUTHOR]

The gastric accommodation reflex is an important mechanism in gastric physiology. However, the aging-associated structural and functional changes in gastric relaxation have not yet been established. Thus, we evaluated the molecular changes of interstitial cell of Cajal (ICC) and neuronal nitric oxide synthase (nNOS) and the function changes in the corpus of F344 rats at different ages (6-, 31-, 74-wk and 2-yr). The proportion of the c-Kit-positive area in the submucosal border (SMB) and myenteric plexus (MP) layer was significantly lower in the older rats, as indicated by immunohistochemistry. The density of the nNOS-positive immunoreactive area also decreased with age in the SMB, circular muscle (CM), and MP. Similarly, the percent of nNOS-positive neuronal cells per total neuronal cells and the proportion of nNOS immunoreactive area of MP also decreased in aged rats. In addition, the mRNA and protein expression of c-Kit and nNOS significantly decreased with age. Expression of stem cell factor (SCF) and the pan-neuronal marker PGP 9.5 mRNA was significantly lower in the older rats than in the younger rats. Barostat studies showed no difference depending on age. Instead, the change of volume was significantly decreased by L-NG63-nitroarginine methyl ester in the 2-yr-old rats compared with the 6-wk-old rats (P = 0.003). Taken together, the quantitative and molecular nNOS changes in the stomach might play a role in the decrease of gastric accommodation with age. [ABSTRACT FROM AUTHOR]

Background: Tight junction proteins (TJPs) play a role in epithelial defense mechanisms. However, the effect of Helicobacter pylori (Hp) on TJPs remains unclear. This study aimed to evaluate the expression of TJPs in relation to Hp infection and eradication in gastric carcinogenesis. Methods: In total, 510 subjects (284 controls and 226 gastric cancer [GC] patients) were prospectively enrolled in the study. The expression of claudin‐1 and ‐2 (CLDN‐1, ‐2), occludin (OCLN), and tight junction protein 1 (TJP1) was measured based on their Hp infection status in normal corpus mucosa and evaluated following Hp eradication using quantitative real‐time polymerase chain reaction (qPCR) and immunohistochemistry (IHC). Results: The expression of TJP1 in Hp+ controls was significantly lower than that in Hp− controls (p = 0.006), whereas it was higher in Hp+ than in Hp− GC patients (p = 0.001). Moreover, the increased expression of TJP1 in Hp+ GC patients was reduced to levels in Hp−within a year after Hp eradication and was maintained for more than 5 years. Furthermore, IHC results for TJP1 were similar to qPCR results. In particular, the higher IHC staining intensity of TJP1 in the cytosol of GC patients (p = 0.019) decreased after Hp eradication (p = 0.040). Conclusion: Hp infection affects TJP expression. The high expression of TJP1 in Hp+ GC patients was restored to control levels after Hp eradication, suggesting that TJP1 plays a role in gastric carcinogenesis. [ABSTRACT FROM AUTHOR]

17β-estradiol (E2) is known to have a protective effect in colorectal cancer (CRC); thus, E2 may be effective for cancer immunotherapy in CRC. The aim of this study is to evaluate the effect of combination therapy with E2 and anti-programmed cell death receptor-1 ligand (PD-L1) antibodies, and the effects of sex and estrogen on colon tumor growth, PD-L1 expression, and tumor-associated cell populations in an MC38 colon tumor model. Male mice showed increased MC38 colon tumor growth and PD-L1 expression in tumor sections as well as higher proportion of cancer-associated fibroblasts (CD45-CD31-CD140a+), PD-L1-expressing tumor cells (CD45-CD274+) and tumor-associated macrophages (TAMs) (CD11b+F4/80+CD274+) compared to female mice. E2 treatment prior to MC38 injection significantly reduced these phenomena in male mice. Furthermore, co-treatment with E2 and anti-PD-L1 antibodies significantly inhibited MC38 tumor growth and reduced PD-L1-expressing cells in male mice compared to treatment with either E2 or anti-PD-L1 antibodies alone. Combination treatment with E2 and anti-PD-L1 decreased TAM population (CD11b+F4/80+) in the tumor mass while increasing M1 TMAs (CD11b+F4/80+CD86+). These results suggest that estrogen inhibits MC38 tumor growth by downregulating PD-L1 expression and regulating tumor-associated cell populations. Furthermore, estrogen boosted the effect of anti-PD-L1 antibody in the MC38 tumor model. [ABSTRACT FROM AUTHOR]

Objective. Antimicrobial resistance of Helicobacter pylori is most important factor in eradication success. GenoType HelicoDR test has been developed for rapid detection of antimicrobial resistance. The present study evaluated the clinical usefulness of GenoType HelicoDR test in Korea. Materials and methods. To detect 23S rRNA for clarithromycin resistance and gyrA mutations for fluoroquinolone resistance, both DNA sequencing after minimal inhibitory test (MIC) and GenoType HelicoDR test were performed in H. pylori isolates from the gastric mucosa of 101 patients. The eradication results of clarithromycin and moxifloxacin-containing triple therapy were evaluated by the 23S rRNA and gyrA mutations. Results. For 42 isolates with A2143G mutation by GenoType HelicoDR, 83.3% (35/42) of concordance rate was estimated with DNA sequencing method and 85.7% (36/42) for MIC test. For 43 isolates with N87K mutation by GenoType HelicoDR, 71.1% (31/43) of concordance rate was estimated with DNA sequencing and 88.4% (38/43) for MIC test. The sensitivity and specificity of GenoType HelicoDR test in determination of 23S rRNA mutation were 94.9% and 87.1%, and those of gyrA 98.2% and 80.0%. The sensitivity and specificity of GenoType HelicoDR test in determination of clarithromycin resistance based on MIC test were 55.0% and 80.0%, for fluoroquinolone 74.4% and 70.0%. Conclusion. GenoType HelicoDR test is useful to determine mutations responsible for clarithromycin or fluoroquinolone-containing eradication failure but has a limitation for the clinical applicability in determination of resistance. [ABSTRACT FROM AUTHOR]

Background and Aim Clinical outcomes of Helicobacter pylori ( HP) infection have been shown to be dependent on the variability of virulence factors. The aim of this study was to evaluate the prevalence of each virulence factor and the association between polymorphisms of the virulence factors of HP, and the clinical outcome of gastroduodenal diseases in South Korea. Methods Four hundred one HP colonies were analyzed (75 colonies from 45 controls; 71 colonies from 39 benign gastric ulcer [ BGU] patients; 102 colonies from 54 duodenal ulcer [ DU] patients; 121 colonies from 77 stomach cancer patients; and 32 colonies from 25 dysplasia patients). Polymerase chain reaction amplifications for vacA, cagA, iceA, oipA, and dupA were performed using DNA extract from HP isolates cultured from mucosal biopsy specimens. dupA was regarded as positive when all of jph0718, jph0719, and dup A were positive. Results Most colonies were composed of vacA s1 (100.0%), i1 (100.0%) and m1 (92.9%), cagA-positive (87.2%), iceA1 (95.8%), oipA-positive (91.2%), and dupA-negative (52.0%) genotypes. dupA was more frequently expressed in BGU (81.3%), DU (74.7%), and dysplasia (41.7%) than control (16.7%) ( P < 0.001). Infection by dupA-positive HP showed an increased risk of BGU (odds ratio 33.06, 95% confidence interval 11.91-91.79) and DU (odds ratio 15.60, 95% confidence interval 6.49-37.49). Conclusion HP infection in South Koreans appears to be closely related to highly virulent strains ( vacA s1/i1/m1, cagA(+), iceA1(+), and oipA(+)), except dupA. dupA has an intimate association with the development of peptic ulcer diseases. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, we investigated the changes of calretinin (CR) expression in the central nervous system of SOD1G93A transgenic mice as an in vivo model of amyotrophic lateral sclerosis (ALS). In wild-type SOD1 (wtSOD1) transgenic mice, many CR-immunoreactive neurons were found in all cortical regions. In the cerebral cortex of SOD1G93A transgenic mice, the number and staining intensity of CR-positive neurons were decreased. In the hippocampal formation, layer-specific alterations in the staining intensity of CR-immunoreactive neurons were observed in the CA1–3 areas and dentate gyrus. In wtSOD1 transgenic mice, CR-immunoreactive neurons with long processes were found in the stratum oriens and stratum radiatum of CA1–3 areas, and heavily stained band-like molecular layer was prominent in the dentate gyrus. CR immunoreactivity was decreased in each layer of CA1–3 areas and dentate gyrus of SOD1G93A transgenic mice. The first demonstration of decreased immunoreactivity for CR in the cerebral cortex and hippocampus of SOD1G93A transgenic mice may provide insights into the pathogenesis of motor neuron degeneration in human ALS although further quantitative studies are needed. [Copyright &y& Elsevier]

Abstract: Although there have been many studies on the regional distribution of Kv channels in the rat and mouse cerebellum, there are no reports about Kv channel distribution in the gerbil, which is used as an ischemia animal model. Therefore, we aimed to investigate differences in the spatial patterning of Kv channel α-subunit isoforms in the gerbil cerebellum. The greatest concentration of Kv1.2 was found in the basket cell axon plexus and terminal regions around the Purkinje cells. Kv1.1 immunoreactivity was also concentrated in this area although the staining intensity was relatively lower. Both Purkinje cell layer and granular layer were intensely stained with anti-Kv1.3 and Kv1.6 antibodies, whereas immunoreactivities for Kv1.4 and Kv1.5 were detected in the Purkinje cell bodies with much lower intensity in the molecular and granular layers. In the cerebellar nuclei, the cell bodies of cerebellar output neurons showed strong immunoreactivities for Kv1.2, Kv1.4, and Kv1.6 with moderate staining for Kv1.3 and Kv1.5 in the cell bodies. This study on the differential localization patterns of Kv1 channel subunits in the gerbil cerebellum may provide helpful guidelines for correlating current types with particular channels and useful data for the future investigations on the pathological conditions such as ischemia and epilepsy. [Copyright &y& Elsevier]

In the present study, we investigated layer-specific changes in insulin-like growth factor-I (IGF-I) receptor localization in the cerebral cortex, hippocampus and cerebellum of neuronal nitric oxide synthase knockout (nNOS−/−) mice using immunohistochemistry. In the cerebral cortex of control mice, moderately stained cells were seen through the layers II–VI in several cortical regions. In nNOS−/− mice, there was a significant decrease in IGF-I receptor immunoreactivity in the same cortical regions. In the hippocampus of control mice, a distinct immunoreactivity pattern was observed in the CA1–3 areas and dentate gyrus. The immunoreactivity for IGF-I receptor was differentially decreased in each layer in nNOS−/− mice. In nNOS−/− cerebellum, IGF-I receptor immunoreactivity was also significantly decreased in each layer of cerebellar cortex and cerebellar nuclei. To clarify whether decreased expression of IGF-I receptor in nNOS−/− mice was specific, the expression of other receptors for IGF-I was also evaluated. Receptor tyrosine kinase type A (TrkA receptor) and TrkB receptor were differentially decreased in each layer of the hippocampus or cerebellum of nNOS−/− mice. Although further studies of functional features of IGF-I systems in the nNOS(−/−) mice are required, our first morphological data may provide insights into NO-induced changes in trophic support as well as basic knowledge required for the study of NO-associated neurological diseases. [Copyright &y& Elsevier]

Background: Antimicrobial resistance of Helicobacter pylori (H pylori) affects the efficacy of eradication therapy. The aim of this study was to estimate the prevalence of primary and secondary resistance of H pylori isolates to antibiotics in Korea. Methods: The present study was performed from 2003 to 2018. Primary resistance was evaluated in 591 patients without any history of eradication and secondary resistance in 149 patients from whom Helicobacter pylori was cultured after failure of eradication. A minimal inhibitory concentration test was performed for amoxicillin, clarithromycin, metronidazole, tetracycline, levofloxacin, and rifabutin using the agar dilution method. Results: An increase in the primary resistance rate was found in clarithromycin (P < .001), metronidazole (P < .001), and both levofloxacin (P < .001) during the study period. The primary resistance rates of amoxicillin and tetracycline were low and stable during the study period. The secondary resistance rate significantly increased in metronidazole and levofloxacin (P = .022 and.039, respectively). Conclusions: The primary and secondary resistance rates of clarithromycin, metronidazole, and levofloxacin for Helicobacter pylori in Korea were high and increased over time. However, the primary and secondary resistance rates of amoxicillin and tetracycline were low and stable over time. These results will help in selecting effective eradication regimens of H pylori in Korea in the future. [ABSTRACT FROM AUTHOR]

The association between adverse effects of PPI and gut microbiota in old age has yet to be elucidated. We assessed changes in the gut microbiota and butyrate levels following the long-term administration of PPIs to old rats and investigated their associations. F344 aged male rats were fed a PPI-supplemented diet for 50 weeks. The ileal microbiota was analysed by metagenomic sequencing of the 16S rRNA, while the butyrate concentration was measured by high-performance liquid chromatography. We observed a significant decrease in microbial diversity following PPI administration in the 2-year-old rats but not in the 74-week-old rats. PPI treatment reduced both commensal bacteria and opportunistic pathogens, particularly in the 2-year-old rats. Enterotypes comprising the majority of the control samples were enriched in Lactobacillus, while other enterotypes in the PPI group were dominated by Turicibacter or Romboutsia. The PPI treatment reduced the butyrate concentrations in the intestines and colons of 74-week-old rats compared to the control group. The abundance of Lactobacillus significantly correlated with butyrate concentrations in 74-week-old rats. In conclusion, long-term administration of PPIs alters the gut microbiota and butyrate concentrations in rats, particularly in old age, which may be an underlying mechanism of PPI-induced adverse effects such as pseudomembranous colitis. [ABSTRACT FROM AUTHOR]

Estrogen is known to have a protective effect in colorectal cancer (CRC) development. Previously, we reported the anti-inflammatory and antitumorigenic effects of 17β-estradiol (E2) in azoxymethane (AOM)/dextran sulfate sodium (DSS)-treated male mice. The aim of this study was to investigate whether ovariectomy in a female AOM/DSS mouse model increases colorectal tumorigenesis and whether tumorigenesis is reduced by estrogen supplementation after ovariectomy. Clinical symptoms and histological severity of colitis and the levels of inflammatory mediators were evaluated in the colon of AOM/DSS-treated ovariectomized (OVX) mice. The levels of E2, myeloperoxidase (MPO), and NF-κB-dependent cytokines (interleukin (IL)-1β and IL-6) were measured by ELISA. Furthermore, quantitative real-time (qRT) PCR and Western blot analysis were performed. Ovariectomy did not aggravate AOM/DSS-induced colitis at 2 weeks. At weeks 10 and 16, ovariectomy significantly increased tumor number and incidence rate in only the proximal colon after AOM/DSS treatment (F_AOM/DSS vs OVX_AOM/DSS), and these increases were significantly reduced by E2 supplementation (OVX_AOM/DSS vs OVX_AOM/DSS/E2). However, ovariectomy did not affect CRC development in the distal colon (F_AOM/DSS vs OVX_AOM/DSS). At week 2, E2 administration to AOM/DSS-treated OVX mice attenuated the histological severity of colitis by decreasing the protein and/or mRNA levels of estrogen receptor alpha (ERα) and NF-κB-related mediators (i.e., COX-2, TNF-α, and IL-6) and by enhancing estrogen receptor beta (ERβ) and nuclear Nrf2 protein expression and the mRNA expression of related antioxidant enzyme genes (i.e., HO-1, GCLC, GCLM, and NQO1). Endogenous estrogen in females protects against the development of proximal colon cancer, and exogenous E2 replacement in OVX female mice showed protective effects against AOM/DSS-induced colitis and carcinogenesis. The mechanism could involve modulating ERs-, NF-κB- and Nrf2-mediated pathways. [ABSTRACT FROM AUTHOR]

Abstract: Background and Aim: rdxA and frxA mutations and enhancement of efflux pump have been suggested as the cause of metronidazole resistance in Helicobacter pylori. This study was performed to investigate the resistance mechanisms related to clinical eradication outcome, and to examine direct involvement of hefA in metronidazole‐resistant isolates with intact rdxA and frxA. Methods: A total of 53 H. pylori‐positive patients who were treated with metronidazole‐containing sequential or quadruple therapy from 2011 to 2015 were enrolled. The metronidazole susceptibility of H. pylori isolates was examined by agar dilution test. Mutations in rdxA and frxA, were analyzed with DNA sequencing, and impact of hefA on metronidazole resistance was examined with quantitative real‐time reverse transcription polymerase chain reaction, knockout and genetic complementation test for hefA. Results: Seven mutation types of rdxA and/or frxA were found in H. pylori isolated from non‐eradicated subjects. rdxA mutation was associated with eradication failure (P = 0.002), and nonsense mutation in rdxA reduced eradication efficacy (P = 0.009). hefA expression was significantly higher in resistant isolates (P < 0.001), especially in rdxA(−)frxA(−) as compared to rdxA(+)frxA(+) (P = 0.027). Resistant isolates with no mutation in rdxA and frxA became susceptible after hefA knockout. Genetic complementation for hefA recovered metronidazole resistance in all of three hefA knockout mutants. Conclusions: These results suggest that rdxA mutations play a critical role in metronidazole resistance as well as the outcomes of eradication therapy. In addition, hefA seems to be directly involved in metronidazole resistance, which explains the resistance in clinical isolates with intact rdxA and frxA. [ABSTRACT FROM AUTHOR]

Background Amoxicillin (Amx) is one of the most important antibiotics for eradication of Helicobacter pylori ( H. pylori). Main determinants of genetically stable Amx resistance are mutations in the C-terminus of penicillin-binding protein 1A ( pbp1A). However, contribution of individual mutation remains unclear. Methods 77 Amx-resistant (AmxR) and 77 Amx-susceptible (AmxS) H. pylori strains were isolated from gastric tissues, and DNA sequencing was performed to compare C-terminus sequences of pbp1A gene between AmxR and AmxS strains. Natural transformation of these mutated genes into amoxicillin-susceptible strains was performed. Results Among many mutations in pbp1A, D479E ( OR: 37.4, 95% CI: 5.53-252.49, P < .001), and T593 mutation ( OR: 32.0, 95% CI: 4.04-252.86, P < .001) independently contributed to Amx resistance in H. pylori strains. In the transformation experiment, T593 mutations were identified in their transformants showing Amx resistance. However, PCR product of D479E was not inserted into recipient ( ATCC 43504) resulting in transformation failure. Conclusion Amx resistance is associated with various substitutions in pbp1A and T593 mutation contributes to Amx resistance of H. pylori. [ABSTRACT FROM AUTHOR]

The aging-associated cellular and molecular changes in esophagus have not been established, yet. Thus we evaluated histological structure, interstitial cells of Cajal (ICCs), neuronal nitric oxide synthase (nNOS)-positive cells, and contractility in the esophagus of Fischer 344 rat at different ages (6-, 31-, 74-weeks, and 2-years). The lamina propria thickness and endomysial area were calculated. The immunoreactivity of c-Kit, nNOS and protein gene product (PGP) 9.5 was counted after immunohistochemistry. Expression of c-Kit, stem cell factor (SCF), nNOS and PGP 9.5 mRNA was measured by real-time PCR, and expression of c-Kit and nNOS protein was detected by Western blot. Isovolumetric contractile force measurement and electrical field stimulation (EFS) were conducted. The lamina propria thickness increased (6 week vs 2 year, P = 0.005) and the endomysial area of longitudinal muscle decreased with aging (6 week vs 2 year, P<0.001), while endomysial area of circular muscle did not significantly decrease. The proportions of NOS-immunoreactive cells and c-Kit-immunoreactive areas declined with aging (6 week vs 2 year; P<0.001 and P = 0.004, respectively), but there was no significant change of PGP 9.5-immunopositiviy. The expressions of nNOS, c-Kit and SCF mRNA also reduced with aging (6 week vs 2 year; P = 0.006, P = 0.001 and P = 0.006, respectively), while the change of PGP 9.5 mRNA expression was not significant. Western blot showed the significant decreases of nNOS and c-Kit protein expression with aging (6 week vs 2 year; P = 0.008 and P = 0.012, respectively). The EFS-induced esophageal contractions significantly decreased in 2-yr-old rat compared with 6-wk-old rats, however, L-NG-Nitroarginine methylester did not significantly increase the spontaneous and EFS-induced contractions in the 6-wk- and 2-yr-old rat esophagus. In conclusion, an increase of lamina propria thickness, a decrease of endomysial area, c-Kit, SCF and NOS expression with preserved total enteric neurons, and contractility in aged rat esophagus may explain the aging-associated esophageal dysmotility. [ABSTRACT FROM AUTHOR]

Background Little is known about the role of gastric microbiota except for Helicobacter pylori (HP) in human health and disease. We compared the differences of human gastric microbiota according to gastric cancer or control and HP infection status and assessed the role of bacteria other than HP. Methods Gastric microbiota of 63 antral mucosal and 18 corpus mucosal samples were analyzed by bar-coded 454 pyrosequencing of the 16S rRNA gene. Antral samples were divided into four subgroups based on HP positivity in pyrosequencing and the presence of cancer. The analysis was focused on bacteria other than HP, especially nitrosating or nitrate-reducing bacteria (NB). The changes of NB in antral mucosa of 16 subjects were followed up. Results The number of NB other than HP (non-HP-NB) was two times higher in the cancer groups than in the control groups, but it did not reach statistical significance. The number of non-HP-NB tends to increase over time, but this phenomenon was prevented by HP eradication in the HP-positive control group, but not in the HP-positive cancer group. Conclusion We could not find the significant role of bacteria other than HP in the gastric carcinogenesis. [ABSTRACT FROM AUTHOR]

Background: Ghrelin has been indicated as one of the etiological factors in functional dyspepsia (FD).Methods: We analyzed 179 patients with FD (based on the Rome III criteria) and 103 asymptomatic healthy individuals (controls) who had undergone endoscopy at Seoul National University Bundang Hospital from February 2011 to June 2014. FD patients were classified into three groups by means of a self-reported questionnaire: patients with postprandial distress syndrome (PDS; n = 49), patients with epigastric pain syndrome (EPS; n = 45), and patients with a combination of these two types (mixed group; n = 85). The fasting blood levels of acyl ghrelin and desacyl ghrelin and messenger RNA (mRNA) expression of preproghrelin in the fundic mucosa were measured by ELISAs and reverse transcription quantitative real-time PCR, respectively. One year after participant enrollment, they were measured again in 79 participants and the changes in the values were compared according to Helicobacter pylori eradication or symptom response.Results: Plasma acyl ghrelin level was lower in the PDS group than in the control and EPS groups (control group 14.1 fmol/mL, PDS group 8.9 fmol/mL, EPS group 13.8 fmol/mL, mixed group 11.3 fmol/mL; P = 0.003 and P = 0.012, respectively). One year after the eradication of H. pylori, plasma acyl ghrelin level was increased and gastric preproghrelin mRNA expression was upregulated (P = 0.004 and P < 0.001, respectively). Patients with abatement of symptoms demonstrated an increase in plasma acyl ghrelin level (from 11.51 to 21.00 fmol/L, P = 0.040).Conclusions: Our results suggest that plasma acyl ghrelin plays a role in the development of PDS. H. pylori eradication upregulates preproghrelin mRNA expression and increases plasma acyl ghrelin level, contributing to the abatement of PDS symptoms. [ABSTRACT FROM AUTHOR]

Background: Epithelial--mesenchymal transition (EMT), in which polarized epithelial cells have mesenchymal cell phenotypes, is thought to be a key process of invasion and metastasis of cancer. Transforming growth factor beta-1 (TGF-β1) is known to be carcinogenic and Helicobacter pylori is a predominant carcinogen of gastric cancer. Our study aimed to determine whether TGF-β1 or H. pylori infection enhances EMT process and cytotoxinassociated gene E (CagE) is associated with EMT. Materials and Methods: Human gastric cancer cell AGS and MKN45 were treated with recombinant TGF-β1 or H. pylori including cagE-negative (DcagE) mutant. Besides the assessment of EMT-related markers expression levels by means of RT-qPCR, Western blot, and immunofluorescence assay, the induction of in vitro EMT on gastric cancer cells (AGS and MKN cell lines) was confirmed by wound-healing assay and invasion assay. Results: When gastric cancer cells were treated with TGF-β1 or various strains of cagE-positive H. pylori, EMT-related marker altered significantly. However, the DcagE mutant did not. Wound-healing assay and invasion assay showed enhanced migration ability of the cells treated with cagE-positive H. pylori but not in DcagE mutant. Conclusions: EMT induction in gastric cancer cells by TGF-β1 was con- firmed. Only infection with cagE-positive H. pylori upregulated the TGF-β1-mediated EMT pathway and consequently promotes EMT. Therefore, H. pylori might induce TGF-β1-mediated EMT associated with the cagE. [ABSTRACT FROM AUTHOR]

Background Sequencing of 16 S ribosomal RNA ( rRNA) gene has improved the characterization of microbial communities. It enabled the detection of low abundance gastric Helicobacter pylori sequences even in subjects that were found to be H. pylori negative with conventional methods. The objective of this study was to obtain a cutoff value for H. pylori colonization in gastric mucosa samples by pyrosequencing method. Materials and Methods Gastric mucosal biopsies were taken from 63 subjects whose H. pylori status was determined by a combination of serology, rapid urease test, culture, and histology. Microbial DNA from mucosal samples was amplified by PCR using universal bacterial primers. 16 S rDNA amplicons were pyrosequenced. ROC curve analysis was performed to determine the cutoff value for H. pylori colonization by pyrosequencing. In addition, temporal changes in the stomach microbiota were observed in eight initially H. pylori-positive and eight H. pylori-negative subjects at a single time point 1-8 years later. Results Of the 63 subjects, the presence of H. pylori sequences was detected in all (28/28) conventionally H. pylori-positive samples and in 60% (21/35) of H. pylori-negative samples. The average percent of H. pylori reads in each sample was 0.67 ± 1.09% in the H. pylori-negative group. Cutoff value for clinically positive H. pylori status was approximately 1.22% based on ROC curve analysis ( AUC = 0.957; p < .001). Helicobacter pylori was successfully eradicated in five of seven treated H. pylori-positive subjects (71.4%), and the percentage of H. pylori reads in these five subjects dropped from 1.3-95.18% to 0-0.16% after eradication. Conclusion These results suggest that the cutoff value of H. pylori sequence percentage for H. pylori colonization by pyrosequencing could be set at approximately 1%. It might be helpful to analyze gastric microbiota related to H. pylori sequence status. [ABSTRACT FROM AUTHOR]

Objective. The eradication rate of 10-day sequential therapy for Helicobacter pylori ( H. pylori) infection was not satisfactory in Korea, probably due to antibiotic resistance. To compare the treatment efficacy of 15-day and 10-day sequential therapy of conventional 7-day proton pump inhibitor (PPI) triple therapy for the treatment of H. pylori infection. Methods. A total of 332 patients with H. pylori infection were randomly assigned to receive either 7-day PPI triple therapy, 10-day sequential therapy or 15-day sequential therapy. Eradication rate, drug compliance, and adverse events were compared among the three regimens. Results. The eradication rates by intention-to-treat analysis were 64.3% (95% CI: 55.5-73.2; 74 of 115 patients), 72.1% (95% CI: 63.6-80.5; 80 of 111 patients), and 80.2% (95% CI: 72.5-87.9; 85 of 106 patients) in the 7-day PPI triple, 10-day and 15-day sequential therapy groups, respectively ( p = 0.032). The eradication rates by per-protocol analysis were 68.5% (95% CI: 59.6-77.4; 74 of 108 patients), 78.4% (95% CI: 70.3-86.5; 80 of 102 patients), and 89.5% (95% CI: 83.2-95.8; 85 of 95 patients) in the 7-day PPI triple, 10-day and 15-day sequential therapy groups, respectively ( p = 0.001). There were no statistically significant differences between the three eradication therapy groups in regard to drug compliance and adverse events. Conclusion. The 15-day sequential therapy demonstrated improved eradication efficacy compared with 7-day PPI triple and 10-day sequential therapy in Korea. [ABSTRACT FROM AUTHOR]

Background Antimicrobial resistance of Helicobacter pylori ( H. pylori) affects the efficacy of eradication therapy. The aim of this study was to estimate the prevalence of primary and secondary resistance of H. pylori isolates to antibiotics and to characterize the risk factors associated with antimicrobial resistance in Korea. Materials and Methods This study was performed during the period of 2003-2012. Primary resistance was evaluated from 347 patients without any history of eradication, and secondary resistance was evaluated in 86 patients from whom H. pylori was cultured after failure of eradication. Minimal inhibitory concentration test was performed for amoxicillin, clarithromycin, metronidazole, tetracycline, azithromycin, levofloxacin, and moxifloxacin using agar dilution method. Primary and secondary resistance rates of H. pylori to 7 antibiotics were evaluated and risk factors for the antibiotic resistance were analyzed. Results Increase in the primary resistance rate was found in amoxicillin (6.3-14.9%, p = .051), clarithromycin (17.2-23.7%, p = .323), and both of levofloxacin and moxifloxacin (4.7-28.1%, p = .002) during the study period. Secondary resistance rate significantly increased in metronidazole, levofloxacin, and moxifloxacin. Increase of resistance occurred after initial failure of eradication therapy in case of clarithromycin ( p < .001), azithromycin ( p < .001), levofloxacin ( p = .011), and moxifloxacin ( p = .020). Multivariable analyses showed that clarithromycin, azithromycin, levofloxacin, and moxifloxacin resistance was associated with previous eradication treatment history. Conclusions The increased primary and secondary antibiotic resistance of H. pylori in Korea is ongoing, and it will become a significant limitation for effective eradication of H. pylori in the future. [ABSTRACT FROM AUTHOR]