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13 result(s) for "Imazu, Noriyuki"
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Ferroptosis in the colon epithelial cells as a therapeutic target for ulcerative colitis
BackgroundFerroptosis, a type of programmed cell death triggered by oxidative stress, was suspected to play a role in ulcerative colitis. Indigo naturalis is highly effective against ulcerative colitis, but its mechanism is unclear. This study found that indigo naturalis treatment suppressed ferroptosis.MethodsWe analyzed 770 mRNA expressions of patients with ulcerative colitis. Suppression of ferroptosis by indigo naturalis treatment was shown using a cell death assay. Malondialdehyde levels and reactive oxygen species were analyzed in CaCo-2 cells treated with indigo naturalis. Glutathione metabolism was shown by metabolomic analysis. Extraction of the ingredients indigo naturalis from the rectal mucosa was performed using liquid chromatograph—mass spectrometry.ResultsGene expression profiling showed that indigo naturalis treatment increased antioxidant genes in the mucosa of patients with ulcerative colitis. In vitro analysis showed that nuclear factor erythroid-2-related factor 2-related antioxidant gene expression was upregulated by indigo naturalis. Indigo naturalis treatment rendered cells resistant to ferroptosis. Metabolomic analysis suggested that an increase in reduced glutathione by indigo naturalis. The protein expression of CYP1A1 and GPX4 was increased in the rectum by treatment with indigo naturalis. The main ingredients of indigo naturalis, indirubin and indigo inhibited ferroptosis. Indirubin was detected in the rectal mucosa of patients with ulcerative colitis who were treated with indigo naturalis.ConclusionsSuppression of ferroptosis by indigo naturalis in the intestinal epithelium could be therapeutic target for ulcerative colitis. The main active ingredient of indigo naturalis may be indirubin.
Small bowel capsule endoscopy examination and open access database with artificial intelligence: The SEE‐artificial intelligence project
Objectives Artificial intelligence (AI) may be practical for image classification of small bowel capsule endoscopy (CE). However, creating a functional AI model is challenging. We attempted to create a dataset and an object detection CE AI model to explore modeling problems to assist in reading small bowel CE. Methods We extracted 18,481 images from 523 small bowel CE procedures performed at Kyushu University Hospital from September 2014 to June 2021. We annotated 12,320 images with 23,033 disease lesions, combined them with 6161 normal images as the dataset, and examined the characteristics. Based on the dataset, we created an object detection AI model using YOLO v5 and we tested validation. Results We annotated the dataset with 12 types of annotations, and multiple annotation types were observed in the same image. We test validated our AI model with 1396 images, and sensitivity for all 12 types of annotations was about 91%, with 1375 true positives, 659 false positives, and 120 false negatives detected. The highest sensitivity for individual annotations was 97%, and the highest area under the receiver operating characteristic curve was 0.98, but the quality of detection varied depending on the specific annotation. Conclusions Object detection AI model in small bowel CE using YOLO v5 may provide effective and easy‐to‐understand reading assistance. In this SEE‐AI project, we open our dataset, the weights of the AI model, and a demonstration to experience our AI. We look forward to further improving the AI model in the future.
Spermidine from arginine metabolism activates Nrf2 and inhibits kidney fibrosis
Kidney metabolism may be greatly altered in chronic kidney disease. Here we report that arginine metabolism is the most altered in unilateral ureteral obstruction (UUO)-induced fibrosis of the kidneys in metabolomic analysis. Spermidine is the most increased metabolite of arginine. In human glomerulonephritis, the amount of spermidine shown by immunostaining is associated with the amount of fibrosis. In human proximal tubule cells, spermidine induces nuclear factor erythroid 2-related factor 2 (Nrf2). Subsequently, fibrotic signals, such as transforming growth factor β1 secretion, collagen 1 mRNA, and oxidative stress, represented by a decrease in the mitochondrial membrane potential is suppressed by spermidine. UUO kidneys of Arg2 knockout mice show less spermidine and significantly exacerbated fibrosis compared with wild-type mice. Nrf2 activation is reduced in Arg2 knockout UUO kidneys. Spermidine treatment prevents significant fibrotic progression in Arg2 knockout mice. Spermidine is increased in kidney fibrosis, but further increases in spermidine may reduce fibrosis. Arginine metabolism is activated and spermidine levels are increased in kidney fibrosis, resulting in activation of the Nrf2 pathway and subsequent protection against interstitial inflammation and fibrosis in renal tubular epithelial cells.
Arginase 2 attenuates ulcerative colitis by antioxidant effects of spermidine
Background Spermidine suppress oxidative stress and is involved in various disease pathogenesis including ulcerative colitis (UC). Arginase 2 (ARG2) plays a central role in the synthesis of spermidine. This study aimed to clarify the effect of endogenously produced spermidine on colitis. Methods The physiological role of ARG2 and spermidine was investigated using Arg2 -deficient mice with reduced spermidine. Immunohistochemical staining of the rectum was used to analyze ARG2 expression and spermidine levels in healthy controls and UC patients. Results In mice with dextran sulfate sodium-induced colitis, ARG2 and spermidine levels were increased in the rectal epithelium. Spermidine protects colonic epithelial cells from oxidative stress and Arg2 knockdown cells reduced antioxidant activity. Organoids cultured from the small intestine and colon of Arg2 -deficient mice both were more susceptible to oxidative stress. Colitis was exacerbated in Arg2 -deficient mice compared to wild-type mice. Supplementation with spermidine result in comparable severity of colitis in both wild-type and Arg2 -deficient mice. In the active phase of UC, rectal ARG2 expression and spermidine accumulation were increased compared to remission. ARG2 and spermidine levels were similar in healthy controls and UC remission patients. Conclusions ARG2 produces spermidine endogenously in the intestinal epithelium and has a palliative effect on ulcerative colitis. ARG2 and spermidine are potential novel therapeutic targets for UC.
USEFULLNESS OF SERUM LEUCINE-RICH ALPHA2-GLYCOPROTEIN AND FECAL CALPROTECTIN ASSURROGATE MARKERS IN ULCERATIVE COLITIS
Abstract BACKGROUND AND AIM Serum Leucine-rich alpha-2 glycoprotein (LRG) was identified as a novel biomarker for rheumatoid arthritis and IBD by using a proteomics approach. Several studies have suggested that serum LRG levels and fecal calprotectin (fCal) were correlated with clinical activities in patients with ulcerative colitis (UC). We compared utility of these biomarkers for monitoring disease activity in UC. METHODS A single-center observational study was conducted at Kyushu University Hospital. A total of 101 patients who underwent colonoscopy during the period from February to December 2021 were enrolled. The associations between endoscopic and histological activity and biomarkers were investigated. Endoscopic activity was defined as Mayo endoscopic score (MES) of 1 or less for mucosal healing and 0 for complete mucosal healing. For histological activity (n=90), Geboes score of 2 or less was defined as histological remission. RESULTS Subjects ranged in age from 16 to 80 years (35 males and 66 females). There were 63 cases of total colitistype, 32 cases of left-sided colitis type, and 6 cases of proctitis type. The MES at enrollment were as follows: MES 0 in 41 cases, MES 1 in 33 cases, MES 2 in 19 cases, and MES 3 in 8 cases. In comparison between the mucosal healing and non-mucosal healing groups, LRG was significantly lower in the mucosal healing group (p<0.0001). The correlation coefficient of LRG with MES was r=0.614 (p<0.0001), which was higher than that of fCal, r=0.414 (p<0.0001). In ROC analysis with mucosal healing as the outcome, the AUC and cut-off value of LRG were 0.781 and 17.9 μg/ml, respectively, and for fCal were 0.850 and 396 μg/g, respectively. In the ROC analysis with complete mucosal healing as the outcome, the AUC for LRG was 0.690, which was lower than the AUC of 0.846 for fCal . When compared by histological remission, LRG was lower in the histological remission group (p<0.001). In the ROC analysis with histological remission as the outcome, the AUC for LRG was 0.722 (cutoff value 14.2 μg/ml) and for fCal was 0.837 (cutoff value 119 μg/g). CONCLUSION Both LRG and fCal are valuable biomarkers reflecting disease activity in UC.
ARGINASE 2 AMELIORATES EXPERIMENTAL COLITIS THROUGH ANTIOXIDANT EFFECTS VIA SPERMIDINE PRODUCTION
Abstract BACKGROUND Spermidine which is a type of polyamine, shows elevated levels in patients with ulcerative colitis and is implicated in the pathogenesis of ulcerative colitis (UC). Arginase 2 (ARG2) plays a critical role in spermidine production. This study aimed to determine the role and mechanism of endogenous spermidine by using ARG2-deficient mice. METHODS The protective role of spermidine against oxidative stress was examined by intracellular reactive oxygen species levels and cell viability. The physiological role of spermidine was investigated using Arg2 knockdown cells with reduced spermidine. The importance of ARG2 in inflammation was examined in the dextran sulfate sodium-induced colitis model. Protein expression levels of ARG2 and accumulation of spermidine in patients with UC were evaluated by immunohistochemistry of the rectum. RESULTS ARG2 protein expression and the accumulation of spermidine were upregulated in the rectum of mice with dextran sulfate sodium colitis. Spermidine upregulated antioxidant genes in the cells. Arg2 knockdown cells showed reduced antioxidant activity. Dextran sulfate sodium colitis was more severe in Arg2-deficient mice, and organoids derived from Arg2-deficient mice showed diminished tolerance to oxidative stress. Furthermore, in the rectum of patients with UC, ARG2 and spermidine expression levels were higher in the active phase than in the remission phase. CONCLUSIONS Endogenous spermidine in the intestinal epithelium induced by ARG2 has a protective role in colitis. Spermidine may be a promising new therapeutic target for inflammatory bowel disease.
Improved Efficiency and Lesion Detection in Small Bowel Capsule Endoscopy Using the Open‐Source Artificial Intelligence Model SEE‐AI
Small bowel capsule endoscopy (CE) produces lengthy videos that are time-consuming to review and susceptible to missed lesions. We evaluated whether an open-source, pretrained artificial intelligence (AI) model (SEE-AI) could improve diagnostic performance and interpretation efficiency compared with conventional reading. We retrospectively analyzed 249 PillCam SB3 examinations performed between 2007 and 2022 at six hospitals, using a two-reader crossover design. SEE-AI (confidence threshold 0.1) generated annotated videos with bounding boxes for eight lesion categories. The primary endpoints were sensitivity for lesion detection on a per-lesion and per-patient basis. Secondary endpoints included specificity, predictive values, overall accuracy, and reading time. A prespecified subgroup analysis evaluated cases of suspected small-bowel bleeding (SSBB), focusing on Saurin P1+P2 hemorrhagic lesions. Across 1550 adjudicated lesions, AI-assisted reading demonstrated higher sensitivity than conventional reading (per-lesion: 98.8% [1532/1550] vs. 86.4% [1339/1550]; per-patient: 99.1% [464/468] vs. 80.3% [376/468]; both < 0.0001). The mean reading time decreased from 17.9 to 13.7 min ( < 0.0001). In SSBB cases ( = 131), sensitivity for P1+P2 lesions improved on both a per-lesion basis (98.2% [439/447] vs. 82.8% [370/447]) and per-patient basis (98.6% [145/147] vs. 73.5% [108/147]), with a shorter reading time (14.1 vs. 18.0 min; all < 0.0001). In this multicenter evaluation, SEE-AI significantly improved lesion detection and reduced reading time for CE interpretation, including SSBB cases, while maintaining openness and reproducibility. AI-assisted reading may reduce clinicians' workload and support the adoption of SEE-AI as a practical tool - and a potential future standard of care - for small bowel CE. N/A.
Diagnostic utility of quantitative analysis of microRNA in bile samples obtained during endoscopic retrograde cholangiopancreatography for malignant biliary strictures
The sensitivity of bile cytology for malignant biliary strictures is not adequate. To overcome this limitation, we evaluated whether quantitative analysis of microRNAs (miRNAs) in bile can provide a precise diagnosis of malignant biliary strictures due to pancreatic cancer (PC) and biliary tract cancer (BTC). This was a retrospective evaluation of miRNA levels in stored bile samples of patients with PC, BTC or benign biliary stricture obtained during biliary drainage from April 2019 to December 2021 at our institution. A total of 113 patients (PC; n = 40, BTC; n = 38, control; n = 35) were enrolled. The miRNA candidates to be quantified were determined with microarray analysis from each 3 patients with PC, BTC and controls. Using microarray analysis, we confirmed four significantly up-regulated miRNAs (miR-1275, miR-6891-5p, miR-7107-5p, miR-3197) in patients with PC and BTC compared to control patients. Quantitative PCR was then performed in 113 bile samples for these miRNAs. miR-1275 was significantly upregulated in PC (p = 0.003) and BTC (p = 0.049) compared to controls, miR-6891-5p was significantly upregulated in PC compared to controls (p = 0.025). In particular, a combination of bile cytology and miR-1275 in bile showed a sensitivity of 77.5% (95% CI, 70.7-77.5%), specificity of 100% (95% CI, 92.2-100%) and an area under the curve (AUC) of 0.93, and provided a significantly greater additional diagnostic effect than bile cytology alone (p = 0.014). This study suggest that bile miRNAs could be potential biomarkers for pancreato-biliary diseases, particularly miR-1275 and miR-6891-5p may be helpful in the diagnosis of PC and BTC.