The causal role of gut microbiota in susceptibility and severity of COVID-19: A bidirectional Mendelian randomization study.

Growing evidence has shown that altered gut microbiota is associated with the pathogenesis of COVID-19, but their causal effects are still unclear. We conducted a bidirectional Mendelian randomization (MR) study to assess the causal effects of gut microbiota on COVID-19 susceptibility or severity, and vice versa. The microbiome genome-wide association studies (GWAS) data of 18 340 individuals and GWAS statistics from the COVID-19 host genetics initiative (38 984 European patients and 1 644 784 controls) were used as exposure and outcomes. The inverse variance weighted (IVW) was used as the primary MR analysis. Sensitivity analyses were performed to validate the robustness, pleiotropy, and heterogeneity of results. In the forward MR, we identified several microbial genera with causal effects on COVID-19 susceptibility (p < 0.05 and FDR < 0.1): Alloprevotella (odds ratio [OR]: 1.088, 95% confidence interval [CI]: 1.021-1.160), Coprococcus (OR: 1.159, 95% CI: 1.030-1.304), Parasutterella (OR: 0.902, 95% CI: 0.836-0.973), and Ruminococcaceae UCG014 (OR: 0.878, 95% CI: 0.777-0.992). The Reverse MR identified that exposure to COVID-19 had causal effects on the depletion of the families Lactobacillaceae (Beta [SE]: -0.220 [0.101]) and Lachnospiraceae (-0.129 [0.062]), the genera Flavonifractor (-0.180 [0.081]) and Lachnoclostridium [-0.181 [0.063]). Our findings supported the causal effect of gut microbiota on the pathogenesis of COVID-19, and infection of COVID-19 might further causally induce gut microbiota dysbiosis.

"M1/M2" Muscularis Macrophages Are Associated with Reduction of Interstitial Cells of Cajal and Glial Cells in Achalasia.

BACKGROUND AND AIMS: Several studies showed muscularis macrophages (MMφ) are associated with GI motility disorders. The purpose of this study was to preliminary explore the association between MMφ and achalasia. METHODS: Tissue samples of the lower esophageal sphincter (LES) high-pressure zone were obtained from 27 achalasia patients and 10 controls. Immunohistochemistry for MMφ, interstitial cells of Cajal (ICC), neuronal nitric oxide synthase (nNOS), and glial cells were conducted. Histological characteristics were compared between groups, and correlation analysis was performed. RESULTS: Fewer ICC was found in achalasia compared with controls (P = 0.018), and the level of M1 macrophages was higher than that in controls no matter in terms of the number or the proportion of M1(P = 0.026 for M1 and 0.037 for M1/MMφ). Statistical differences were found between two groups in terms of proportion of M2 and ratio of M1 to M2 (P = 0.048 for M2/ MMφ and < 0.001 for M1/M2). For the correlation analysis, significant correlations were detected between levels of nNOS, ICC, and glial cells in patients with achalasia (P = 0.026 for nNOS and ICC, 0.001 for nNOS and glial cells, 0.019 for ICC and glial cells). There were significant correlations between M2/MMφ and levels of ICC (P = 0.019), glial cells (P = 0.004), and nNOS (P = 0.135). CONCLUSION: Patients with achalasia had a higher level of M1/M2 ratio in LES and significant correlations were found between M2/MMφ and numbers of ICC and glial cells, which suggested that MMφ were probably associated with occurrence and development of achalasia.

Risk factors for the failure of endoscopic resection of gastric submucosal tumors: a long-term retrospective case-control study.

OBJECTIVE: Endoscopic resection (ER) is an effective treatment method for gastric submucosal tumors (G-SMTs), but endoscopic resection failure requires emergency surgery. The purpose of this study was to assess potential risk factors for endoscopic resection failure. METHODS: A total of 1041 patients with G-SMT undergoing endoscopic resection were enrolled. Twenty-five patients in whom endoscopic resection failed, requiring a transition to surgery midway through the operation, were included in the failed group, and 1016 patients who received successful endoscopic resection were included in the successful endoscopic resection group. Baseline and lesion characteristics were recorded, and the differences in tumor characteristics and risk factors for resection failure of G-SMT were analyzed. Sensitivity analysis was performed to detect the stability of the indicator. RESULTS: Of the 1041cases included, there were 25 cases (2.4%) of failed endoscopic resection. Binary logistic analysis showed that the independent risk factors included tumors originating from deep muscularis propria(OR = 14.42, 95% CI 4.47-46.52), size > 3 cm (OR = 7.75, 95% CI 2.64-22.70), exophytic growth pattern (OR = 4.98, 95% CI 1.62-15.29), endoscopist with less experience (OR = 5.99, 95% CI 1.07-12.19), and irregular borders (OR = 4.13, 95% CI 1.40-12.19). The stable risk factors were tumors size, tumor origin and growth pattern according to sensitivity analysis. CONCLUSIONS: Tumors originating from the deep muscularis propria, tumor size > 3 cm, endoscopists with less experience, an exophytic growth pattern, and irregular boundaries were found to be independent risk factors for endoscopic resection failure. To reduce the risk of endoscopic resection failure, physicians should carefully evaluate G-SMT characteristics preoperative.

Differential diagnosis for esophageal protruded lesions using a deep convolution neural network in endoscopic images.

BACKGROUND AND AIMS: Recent advances in deep convolutional neural networks (CNNs) have led to remarkable results in digestive endoscopy. In this study, we aimed to develop CNN-based models for the differential diagnosis of benign esophageal protruded lesions using endoscopic images acquired during real clinical settings. METHODS: We retrospectively reviewed the images from 1217 patients who underwent white-light endoscopy (WLE) and EUS between January 2015 and April 2020. Three deep CNN models were developed to accomplish the following tasks: (1) identification of esophageal benign lesions from healthy controls using WLE images; (2) differentiation of 3 subtypes of esophageal protruded lesions (including esophageal leiomyoma [EL], esophageal cyst (EC], and esophageal papilloma [EP]) using WLE images; and (3) discrimination between EL and EC using EUS images. Six endoscopists blinded to the patients' clinical status were enrolled to interpret all images independently. Their diagnostic performances were evaluated and compared with the CNN models using the area under the receiver operating characteristic curve (AUC). RESULTS: For task 1, the CNN model achieved an AUC of 0.751 (95% confidence interval [CI], 0.652-0.850) in identifying benign esophageal lesions. For task 2, the proposed model using WLE images for differentiation of esophageal protruded lesions achieved an AUC of 0.907 (95% CI, 0.835-0.979), 0.897 (95% CI, 0.841-0.953), and 0.868 (95% CI, 0.769-0.968) for EP, EL, and EC, respectively. The CNN model achieved equivalent or higher identification accuracy for EL and EC compared with skilled endoscopists. In the task of discriminating EL from EC (task 3), the proposed CNN model had AUC values of 0.739 (EL, 95% CI, 0.600-0.878) and 0.724 (EC, 95% CI, 0.567-0.881), which outperformed seniors and novices. Attempts to combine the CNN and endoscopist predictions led to significantly improved diagnostic accuracy compared with endoscopists interpretations alone. CONCLUSIONS: Our team established CNN-based methodologies to recognize benign esophageal protruded lesions using routinely obtained WLE and EUS images. Preliminary results combining the results from the models and the endoscopists underscored the potential of ensemble models for improved differentiation of lesions in real endoscopic settings.

Effect and mechanisms of sacral nerve stimulation on visceral hypersensitivity mediated by nerve growth factor.

To investigate the efficacy of sacral nerve stimulation (SNS) on nerve growth factor (NGF) mediated visceral sensitivity in normal rat and visceral hypersensitivity model rats. 120 male newborn rats were randomly divided into 6 groups: group A was normal model group; group B ~ F were all sensitized with acetic acid enema and grouped again. Group c2 was given NGF antagonist, d2 group was given NGF agonist, e2 group was given PI3K inhibitor, and f2 group was given PLC-γ inhibitor. After treatment, the expression of NGF, TrKA, PI3K, AKT, PLC-γ, NF-κB, TRPV1, pTRPV1 and intracellular Ca2+ content were detected. The expression of protein TRPV1 and pTRPV1 was increased, and Ca2+ was increased in the visceral hypersensitive group. NGF, TrKA in NGF antagonist group, PI3K, AKT, NF-κB in PI3K inhibitor group, PLC-γ in PLC-γ inhibitor group were all almost not expressed. The relative expression of NGF, TrKA, PI3K, AKT, PLC-γ and NF-κB in NGF antagonist group was lower than that in visceral hypersensitivity group and NGF activator group (P < .01). The relative expression of NGF, TrKA, PI3K and AKT mRNA in NGF antagonist group was lower than that in the normal model group (P < .01). There was no significant difference in the relative expression of PLC-γ and NF-κB mRNA (P > .05). The expression level of MAPK, ERK1 and ERK2 in visceral hypersensitivity group was higher than that in PI3K inhibitor group and PLC-γ inhibitor group. The normal group Ca2+ curve was flat, and the NGF agonist group had the highest Ca2+ curve peak. Calcium concentration in visceral hypersensitivity group was higher than that in PI3K inhibitor group and that in PLC-γ inhibitor group was higher than that in NGF antagonist group. The binding of TrkA receptor to NGF activates the MAPK/ERK pathway, the PI3K/Akt pathway and the PLC-γ pathway, causing changes in the fluidity of intracellular and extracellular Ca2+ , resulting in increased sensitivity of visceral tissues and organs.

MICAL1 facilitates breast cancer cell proliferation via ROS-sensitive ERK/cyclin D pathway.

Molecule interacting with CasL 1 (MICAL1) is a multidomain flavoprotein mono-oxygenase that strongly involves in cytoskeleton dynamics and cell oxidoreduction metabolism. Recently, results from our laboratory have shown that MICAL1 modulates reactive oxygen species (ROS) production, and the latter then activates phosphatidyl inositol 3-kinase (PI3K)/protein kinase B (Akt) signalling pathway which regulates breast cancer cell invasion. Herein, we performed this study to assess the involvement of MICAL1 in breast cancer cell proliferation and to explore the potential molecular mechanism. We noticed that depletion of MICAL1 markedly reduced cell proliferation in breast cancer cell line MCF-7 and T47D. This effect of MICAL1 on proliferation was independent of wnt/ß-catenin and NF-κB pathways. Interestingly, depletion of MICAL1 significantly inhibited ROS production, decreased p-ERK expression and unfavourable for proliferative phenotype of breast cancer cells. Likewise, MICAL1 overexpression increased p-ERK level as well as p-ERK nucleus translocation. Moreover, we investigated the effect of MICAL1 on cell cycle-related proteins. MICAL1 positively regulated CDK4 and cyclin D expression, but not CDK2, CDK6, cyclin A and cyclin E. In addition, more expression of CDK4 and cyclin D by MICAL1 overexpression was blocked by PI3K/Akt inhibitor LY294002. LY294002 treatment also attenuated the increase in the p-ERK level in MICAL1-overexpressed breast cancer cells. Together, our results suggest that MICAL1 exhibits its effect on proliferation via maintaining cyclin D expression through ROS-sensitive PI3K/Akt/ERK signalling in breast cancer cells.

[Predictors of efficacy of biofeedback therapy in patients with chronic constipation].

OBJECTIVE: To explore the anorectal physiology, psychological state, quality of life, lifestyle of patients with chronic constipation (CC) and evaluate the factors which potentially predict the efficacy of biofeedback therapy (BF). METHODS: Seventy CC patients receiving BF training were enrolled in this study. Anorectal physiology, Zung's Self-Rating Depression Scale (SDS), Zung's Self-Rating Anxiety Scale (SAS) and Chinese version of the MOS 36-item short form healthy survey (SF-36), lifestyle scale were recorded before BF training. A bowel symptom measurement including five major symptoms was recorded before and after BF training. The improvement in the symptom score was considered as criteria of clinical efficacy of BF therapy. Thirty-two possible influencing factors of efficacy of BF therapy were selected. Univariate analysis and multivariate analysis were conducted to assess the independent predictors. RESULTS: The results of univariate analysis showed that efficacy of BF therapy was positively correlated to the role physical (r = 0.256, P = 0.031), negatively correlated to the score of SDS (r = -0.315, P = 0.007) and the first sensation threshold (r = -0.278, P = 0.020). The multivariate analysis showed the score of SDS (ß = -0.263, P = 0.033) and the first sensation volume (ß = -0.281, P = 0.013) were the independent predicator of efficacy of BF therapy. CONCLUSION: CC patients who tended to depression state and rectal hyposensitivity have poor response to BF therapy. To treat these patients purposely could optimize the efficacy of BF therapy.

Value of adjunctive evidence from MII-pH monitoring and high-resolution manometry in inconclusive GERD patients with AET 4-6.

OBJECTIVES: Gastro-esophageal reflux disease (GERD) is a common disease in gastroenterology outpatients. However, some patients with typical reflux symptoms does not satisfy diagnostic criteria. This study was to explore the value of adjunctive evidence from multichannel intraluminal impedance-pH (MII-pH) monitoring and esophageal high-resolution manometry (HRM) in inconclusive GERD patients with acid exposure time (AET) 4-6%. METHODS: Endoscopy, MII-pH monitoring and esophageal HRM were retrospectively analyzed from consecutive patients with typical reflux symptoms in a tertiary hospital from 2013 to 2019. Patients were categorized as conclusive or inconclusive GERD according to AET. Adjunctive evidence for GERD diagnosis from Lyon Consensus were collected and analyzed. RESULTS: Among 147 patients with typical reflux symptoms, conclusive GERD was found in only 31.97% of patients (N = 47). The remaining 100 patients (68.03%) were inconclusive GERD, of whom 28% (N = 28) had AET 4-6%. These patients suffered similar reflux burden and impaired esophageal movement. Inconclusive GERD patients with AET 4-6% had lots of positive adjunctive evidence from HRM and MII-pH monitoring. In receiver operating characteristic analysis, mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPWI) had an area under the curve (AUC) of 0.839 (CI: 0.765-0.913, p < 0.001) and 0.897 (CI: 0.841-0.953, p < 0.001), respectively, better than total reflux episode (AUC of 0.55, p = 0.33). When MNBI was combined with PSPWI, the AUC was elevated to 0.910 (CI: 0.857-0.963, p < 0.001). CONCLUSIONS: Inconclusive GERD patients with AET 4-6% have similar acid burden and esophagus motility dysfunction to GERD patients. MNBI and PSPWI are pivotal adjunctive evidence for diagnosing GERD when AET is borderline.

Esophageal Nocturnal Baseline Impedance and Post-reflux Swallow-induced Peristaltic Wave Index in Identifying Proton Pump Inhibitor-refractory Non-erosive Reflux Disease.

BACKGROUND/AIMS: Esophageal mean nocturnal baseline impedance (MNBI) levels and post-reflux swallow-induced peristaltic wave (PSPW) index could increase the diagnostic value of 24-hour multichannel intraluminal impedance and pH monitoring in patients with gastroesophageal reflux disease. This study aims to compare the MNBI and PSPW index in patients with no evidence of erosive reflux disease. METHODS: Impedance-pH monitoring tracings from 70 patients, 50 with non-erosive reflux disease (NERD) and 20 with functional heartburn (FH), were reviewed. According to proton pump inhibitors (PPI) treatment response, NERD patients were divided into NERD/PPI responders and NERD/PPI nonresponders. MNBI, PSPW index, and intercellular spaces were measured and compared among each group. RESULTS: MNBI values and PSPW index were lower in NERD patients than in FH (P < 0.01 and P < 0.05, respectively). MNBI positively correlated with PSPW index (r = 0.525, P < 0.001). NERD/PPI responders had lower MNBI values and PSPW index compared to NERD/PPI nonresponders (both P < 0.01). MNBI and PSPW index distinguished NERD from FH patients with an area under the curve of 0.914 and 0.677, respectively. Wider intercellular space could be identified in patients with NERD (P < 0.01). CONCLUSION: MNBI and PSPW index may differentiate NERD from FH patients and relate to PPI treatment efficacy in patients with NERD.

Sex-Based Differences in pH Parameters and Esophageal Impedance of Patients With Gastroesophageal Reflux Disease.

Background/Aims: The incidence of reflux esophagitis (RE) has a striking predominance in males. Conversely, non-erosive reflux disease (NERD) is more common in females. This imbalance of gastroesophageal reflux disease (GERD) implies sex-related differences in its pathogenesis. However, limited studies have analyzed the sex-based differences in pH parameters and esophageal impedance of GERD patients. Methods: This study evaluated sex-based pathogenesis differences by comparing reflux episodes, mean nocturnal baseline impedance (MNBI) values, and post-reflux swallow-induced peristaltic wave (PSPW) index values of males with GERD and females with GERD using 24-h multichannel intraluminal impedance and pH monitoring. Results: We analyzed 181 patients (102 males and 79 females) with GERD. Reflux symptom index (RSI) scores were higher in females than that in males (P < 0.05). Males had significantly longer acid exposure times, higher DeMeester scores, and more acid reflux episodes than females (P < 0.05). Females had more instances of weakly acidic reflux than males (P < 0.01). The PSPW index values of males and females were similar (P > 0.05). Compared with females, males had lower MNBI values for the mid and distal esophagus (P < 0.05). However, with increasing age, the MNBI values of females decreased more rapidly than those of males. MNBI values of elderly patients of both sexes older than 60 years were similar. Conclusions: Acid reflux is more likely to occur in males; however, females tend to have more instances of weakly acid reflux. The integrity of the esophageal mucosa is more fragile in males than in females; however, the esophageal mucosal barrier attenuates more rapidly with increasing age in females than in males.

Factors of Reflux Episodes With Post-reflux Swallow-induced Peristaltic Wave in Gastroesophageal Reflux Disease.

Background/Aims: It is known that post-reflux swallow-induced peristaltic wave (PSPW) index represents the chemical clearance of the esophagus. However, few studies have explored why some reflux episodes could induce PSPW while others in the same patient could not. The purpose of this study is to investigate the characteristics of reflux episodes which could elicit PSPW. Methods: In this study, 269 reflux episodes were detected, of which 90 with a PSPW and 179 without a PSPW. Comparisons were made between the characteristics of reflux episodes with a PSPW and without a PSPW. The characteristics were including nadir pH, pH drop, proximal extent (cm, sec), ascending velocity (cm/sec), volume clearance time, acid clearance time, percentage acidic (%), 15 to 60-minute acid burden (seconds), and 15- to 60-minute volume burden (seconds). The characteristics between the 2 groups were compared through performing Wilcoxon signed rank test. Results: Reflux episodes followed by a PSPW were significantly associated with a higher proximal extent than those without a PSPW. After the reflux episodes, higher volume clearance time and larger volume burden were more likely to trigger a PSPW. However, there were no significant differences between the 2 groups in nadir pH, pH drop, ascending velocity, acid clearance time, percentage acidic, or acid burden. Conclusions: The role of acid seems to be less important in a reflux episode inducing a PSPW. Proximal reflux episodes are more likely to induce a PSPW. The depression of volume clearance may also be an important factor in eliciting a PSPW.

Characteristics of intestinal microflora involved insacral nerve stimulation affecting visceral hypersensitivity.

OBJECTIVE: This study was to investigate the effect of intestinal flora-intestinal-brain on the visceral sensitivity of normal rat and visceral hypersensitivity model rats, and to explore the effect of intestinal flora-intestinal-brain axis on visceral hypersensitivity in rats. METHODS: Sixty SD male newborn rats were randomly divided into 4 groups according to the random number table: group A, group B, group C, and group D, with 15 rats in each group. 15 sterile SD newborn rats, numbered E group. Group A: normal model group; group B, group C, group D, group E, all used acetogen enema sensitization method to establish a visceral hypersensitivity model. Group C was given the vancomycin antibiotic before the model group and in group D sacral nerve stimulation (SNS) was given after modeling. At the end of the treatment period, the visceral sensitivity, intestinal flora expression, expression of NGF, TrKA, NF-κB, TRPV1, pTRPV1, IL-1ß, IL-10, IL-22, TNF-α, 5-HT, and γ-GABA were measured in each group. RESULTS: (1) The VMR values of the sterile rat model group were significantly different from those of the model group and the SNS stimulation model group (P<0.01). The VMR values of the antibiotic model group were statistically significant compared with the SNS stimulation model group (P<0.01). (2) There was no bacterial growth in the sterile rat model group. The expression levels of the four bacterial groups were significantly different between the antibiotic model group and the SNS stimulation model group (P<0.01). (3) The expression of NGF and TrKA in the SNS stimulation model was higher than that in the antibiotic model group (P<0.05). The expression of NF-κB and pTRPV1 was lower than that in the model group (P<0.05). The NGF, TrKA, NF-κB, and pTRPV1 were hardly expressed, which was significantly lower than the other groups (P<0.05). (4) There was no significant difference in the content of each index between the normal model group and the antibiotic model group (P > 0.05), IL-10 and 5-HT levels in the normal model group, the sterile rat model group, and the antibiotic model. There was no significant difference between the group and the sterile rat model group (P > 0.05). The difference was statistically significant (P<0.01). CONCLUSION: The neurotransmitter produced by the intestinal flora can bind to the receptor TrkA and the translocation channel TRPV1 of intestinal tissue and CNS tissue, causing intestinal sensitivity changes.

Retraction Note: HDAC6 inhibitor TST strengthens the antiproliferative effects of PI3K/mTOR inhibitor BEZ235 in breast cancer cells via suppressing RTK activation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

EGF Stimulates Rab35 Activation and Gastric Cancer Cell Migration by Regulating DENND1A-Grb2 Complex Formation.

Aims: The aim of this study was to reveal the specific molecular mechanisms by which DENND1A accepts EGF signaling and activates Rab35 in gastric cancer. Methods: The expression of proteins related to DENND1A was examined by western blot analysis. Activation of Rab35 was assessed by GST-pulldown. The interaction of DENND1A and Grb2 was assessed by GST-pulldown and co-immunoprecipitation assays. The relationship between DENND1A and cell migration and invasion was detected using wound healing and transwell by gene overexpression and RNA interference. Results: EGF stimulation significantly promoted cell migration, whereas transfection with siRab35 partially inhibited EGF-promoted cell migration. DENND1A is also involved in these processes and active Rab35. Moreover, DENND1A binds to the N-terminal and C-terminal SH3 domains of Grb2 through PRD. Of special interest is the observation that EGFR can recruit Grb2-DENND1A complex under EGF stimulation. Further results reveal that the higher the expression of DENND1A, the shorter progression-free survival of gastric cancer patients. Conclusion: In summary, we confirmed that EGF-Grb2-DENND1A-Rab35 signaling pathway with the interaction of DENND1A and Grb2 as a regulatory center could regulate gastric cancer cell migration and invasion. Ultimately, the expression level of DENND1A predicts the survival status of gastric cancer patients and may become one of the important targets for the treatment of gastric cancer.

HDAC6 inhibitor TST strengthens the antiproliferative effects of PI3K/mTOR inhibitor BEZ235 in breast cancer cells via suppressing RTK activation.

NVP-BEZ235 (BEZ235), an available dual PI3K/mTOR inhibitor, showed antitumor effect and provided a therapy strategy in carcinomas. However, the acquired upregulation of multiple receptor tyrosine kinases (RTKs) by NVP-BEZ235 in tumors limits its clinical efficacy. HDAC6, a class II histone deacetylase, is associated with expressions of multiple RTKs. The aim of this study was to detect whether co-treatment with HDAC6 inhibitor Tubastatin A (TST) would enhance the anticancer effects of BEZ235 in breast cancer cells. In this study, we described that treatment of breast cancer cell lines (T47D, BT474, and MDA-MB-468) with BEZ235 significantly triggered PI3K/mTOR signaling inactivation and increased multiple RTK expression, including EGFR, HER2, HER3, IGF-1 receptor, insulin receptor, and their phosphorylation levels. The adding of TST destabilized these RTKs in those breast cancer cells. Co-treatment with BEZ235 and TST reduced cell proliferative rate by strengthening Akt inactivation. In addition, the combination of these two drugs also cooperatively arrested cell cycle and DNA synthesis. In conclusion, the co-treatment with PI3K/mTOR inhibitor BEZ235 and HDAC6 inhibitor TST displayed additive antiproliferative effects on breast cancer cells through inactivating RTKs and established a rationable combination therapy to treat breast cancer.

Esophageal Body Motility for Clinical Assessment in Patients with Refractory Gastroesophageal Reflux Symptoms.

BACKGROUND/AIMS: Little data exists about esophageal body dysmotility and reflux patterns in refractory gastroesophageal reflux disease (RGERD) patients off therapy. We aimed to evaluate effects of esophageal body dysmotility on reflux parameters in RGERD patients by combining impedance-pH monitoring and high-resolution manometry (HRM). METHODS: We retrospectively reviewed the impedance-pH data and HRM metrics in patients with refractory gastroesophageal reflux symptoms. Impedance-pH monitoring and manometric data were compared between 2 groups: ineffective esophageal motility (IEM) and normal motility. RESULTS: Forty-eight patients (30 males, mean age 54.5 years) were included (16 erosive esophagitis, 24 non-erosive reflux disease, and 8 functional heartburn), amongst which 24 subjects showed IEM, and others had normal motility. Number of patients who had a large break in the IEM group was significantly higher than that of normal motility patients. IEM group had more patients with weakly acid reflux and long term acid reflux than the normal group (P = 0.008, P = 0.004, respectively). There was no statistical difference in baseine impedance levels from z4 to z6 between the 2 groups (2911 ± 1160 Ω vs 3604 ± 1232 Ω, 2766 ± 1254 Ω vs 3752 ± 1439 Ω, 2349 ± 1131 Ω vs 3038 ± 1254 Ω, all P > 0.05). Acid exposure time, numbers of long term acid reflux and weakly acid reflux showed strong negative correlation with esophageal body motility and/or lower esophageal sphincter function. CONCLUSIONS: IEM was associated more with acid exposure, abnormal weakly acid reflux, and long term acid reflux in RGERD patients. These data suggested the role of esophageal body dysmotility in the pathophysiological mechanisms of RGERD patients.

Role of altered esophageal intraluminal baseline impedance levels in patients with gatroesophageal reflux disease refractory to proton pump inhibitors.

Numerous studies have investigated utility of esophageal intraluminal baseline impedance levels (BILs) in gastroesophageal reflux disease (GERD). However, effect of BILs in refractory GERD (RGERD) has not been well investigated. The aim of this study is to evaluate role of BILs in RGERD patients. Total 62 subjects with refractory gastroesophageal reflux symptoms underwent 24-hour impedance-pH monitoring and gastroendoscopy. Distal BILs in acid reflux type were significantly lower than those in nonacid reflux type and functional heartburn (FH) group. Distal BILs of reflux esophagitis (RE) patients were lower than those of nonerosive reflux disease (NERD) patients, while there were no statistical significance between 2 groups. Patients with severe esophagitis had lower distal BILs than those with mild esophagitis and NERD patients, and patients with severe esophagitis in acid reflux type had the lowest distal BILs. Distal BILs were significantly negatively correlated with DeMeester score, episodes of acid reflux, and acid exposure time, but no correlated with episodes of nonacid reflux. Characteristics of BILs in RGERD patients were similar with those in GERD patients, but might be more complicated. Evaluating BILs in RGERD patients could achieve a better understanding of pathophysiology in RGERD.

EGF-stimulated activation of Rab35 regulates RUSC2-GIT2 complex formation to stabilize GIT2 during directional lung cancer cell migration.

Non-small cell lung cancer (NSCLC) remains one of the most metastasizing tumors, and directional cell migration is critical for targeting tumor metastasis. GIT2 has been known to bind to Paxillin to control cell polarization and directional migration. However, the molecular mechanisms underlying roles of GIT2 in controlling cell polarization and directional migration remain elusive. Here we demonstrated GIT2 control cell polarization and direction dependent on the regulation of Golgi through RUSC2. RUSC2 interacts with SHD of GIT2 in various lung cancer cells, and stabilizes GIT2 (Mazaki et al., 2006; Yu et al., 2009) by decreasing degradation and increasing its phosphorylation. Silencing of RUSC2 showed reduced stability of GIT2, defective Golgi reorientation toward the wound edge and decreased directional migration. Moreover, short-term EGF stimulation can increase the interaction between RUSC2 and GIT2, prolonged stimulation leads to a decrease of their interaction through activating Rab35. Silencing of Rab35 also reduced stability and phosphorylation of GIT2 and decreased cell migration. Taken together, our study indicated that RUSC2 participates in EGFR signaling and regulates lung cancer progression, and may be a new therapeutic target against lung cancer metastasis.