Bidirectional regulation of the brain-gut-microbiota axis following traumatic brain injury

JOURNAL/nrgr/04.03/01300535-202508000-00002/figure1/v/2024-09-30T120553Z/r/image-tiff Traumatic brain injury is a prevalent disorder of the central nervous system. In addition to primary brain parenchymal damage, the enduring biological consequences of traumatic brain injury pose long-term risks for patients with traumatic brain injury; however, the underlying pathogenesis remains unclear, and effective intervention methods are lacking. Intestinal dysfunction is a significant consequence of traumatic brain injury. Being the most densely innervated peripheral tissue in the body, the gut possesses multiple pathways for the establishment of a bidirectional "brain-gut axis" with the central nervous system. The gut harbors a vast microbial community, and alterations of the gut niche contribute to the progression of traumatic brain injury and its unfavorable prognosis through neuronal, hormonal, and immune pathways. A comprehensive understanding of microbiota-mediated peripheral neuroimmunomodulation mechanisms is needed to enhance treatment strategies for traumatic brain injury and its associated complications. We comprehensively reviewed alterations in the gut microecological environment following traumatic brain injury, with a specific focus on the complex biological processes of peripheral nerves, immunity, and microbes triggered by traumatic brain injury, encompassing autonomic dysfunction, neuroendocrine disturbances, peripheral immunosuppression, increased intestinal barrier permeability, compromised responses of sensory nerves to microorganisms, and potential effector nuclei in the central nervous system influenced by gut microbiota. Additionally, we reviewed the mechanisms underlying secondary biological injury and the dynamic pathological responses that occur following injury to enhance our current understanding of how peripheral pathways impact the outcome of patients with traumatic brain injury. This review aimed to propose a conceptual model for future risk assessment of central nervous system-related diseases while elucidating novel insights into the bidirectional effects of the "brain-gut-microbiota axis."

Iron deposition in gastric black spots: Clinicopathological insights and NanoSuit-correlative light and electron microscopy analysis

Objectives

Black spots (BSs) are lentiginous findings observed in the gastric body and fundus during upper gastrointestinal endoscopy and are predominantly seen in patients undergoing Helicobacter pylori eradication treatment. However, the detailed patient background and exact composition are poorly understood. This study aims to clarify the clinicopathological features of BSs, examine patient demographics, and use the NanoSuit-correlative light and electron microscopy (CLEM) method combined with scanning electron microscopy-energy dispersive X-ray spectroscopy for elemental analysis.

Methods

Patients who underwent upper gastrointestinal endoscopy between 2017 and 2022 were included. Data on age, medications, blood tests, and H. pylori infection status were retrospectively gathered from medical records. Univariate analysis was conducted to examine BS presence, with results then used in a multivariate model to identify associated risk factors. Additionally, pathological specimens from patients with BSs were analyzed for elemental composition using the NanoSuit-CLEM method combined with scanning electronmicroscopy-energy dispersive X-ray spectroscopy.

Results

An analysis of 6778 cases identified risk factors for BSs, including older age and using proton pump inhibitors, statins, corticosteroids, and antithrombotic drugs. Endoscopically, BSs correlated with higher gastric atrophy and lower active H. pylori infection. Iron deposition at BS sites was specifically identified using NanoSuit-CLEM.

Conclusions

BSs on gastrointestinal endoscopy may indicate an absence of active H. pylori inflammation. The discovery of iron deposition within BSs using the NanoSuit-CLEM method has offered new insights into the possible causative factors and advances our understanding of the etiology of BSs, bringing us closer to unraveling the underlying mechanisms of their formation.

Comparison of remimazolam and midazolam for sedation during colonoscopy in Japanese patients: A propensity score matching analysis

Objectives

To compare the efficacy and safety of sedation with midazolam and remimazolam for colorectal endoscopy.

Methods

This single-center, two-arm, post-hoc analysis of the REM-IICTJP01 study investigated the efficacy and safety of remimazolam for gastrointestinal endoscopic sedation. We enrolled 40 and 208 patients who underwent colonoscopy under remimazolam and midazolam sedation, respectively, during the same period. The primary outcome was the time from the end of the colonoscopy until discharge. The secondary outcomes included the time from the end of the colonoscopy until awakening, dosage, and adverse events. Propensity score matching was employed to eliminate the effect of confounding factors.

Results

Thirty-seven patients in each group were matched. After propensity matching, the time to awakening after colonoscopy was 28.0 (13.0-37.0) min in the midazolam group and 0 (0-0) min in the remimazolam group; moreover, the time till discharge was 40.0 (35.0-46.5) min in the midazolam group and 0 (0-5.0) min in the remimazolam group, both of which were significantly shorter in the remimazolam group (p < 0.01). The number of additional doses was 0 (0-0) and 2 (1-3) in the midazolam and remimazolam groups, respectively. The total dose was 2.0 (2.0-3.5) and 6.0 (5.0-7.0) mg in the midazolam and remimazolam groups, respectively.

Conclusions

Remimazolam yielded significantly faster times to awakening and discharge safely compared to midazolam.

Establishment of a swine model of delayed bleeding after endoscopic procedure

Objectives

Although delayed bleeding after endoscopic procedures has become a problem, currently, there are no appropriate animal models to validate methods for preventing it. This study aimed to establish an animal model of delayed bleeding after endoscopic procedures of the gastrointestinal tract.

Methods

Activated coagulation time (ACT) was measured using blood samples drawn from a catheter inserted into the external jugular vein of swine (n = 7; age, 6 months; mean weight, 13.8 kg) under general anesthesia using the cut-down method. An upper gastrointestinal endoscope was inserted orally, and 12 mucosal defects were created in the stomach by endoscopic mucosal resection using a ligating device. Hemostasis was confirmed at this time point. The heparin group (n = 4) received 50 units/kg of unfractionated heparin via a catheter; after confirming that the ACT was ≥200 s 10 min later, continuous heparin administration (50 units/kg/h) was started. After 24 h, an endoscope was inserted under general anesthesia to evaluate the blood volume in the stomach and the degree of blood adherence at the site of the mucosal defect.

Results

Delayed bleeding was observed in three swine (75%) in the heparin-treated group, who had a maximum ACT of >220 s before the start of continuous heparin administration. In the non-treated group (n = 3), no prolonged ACT or delayed bleeding was observed at 24 h.

Conclusion

An animal model of delayed bleeding after an endoscopic procedure in the gastrointestinal tract was established using a single dose of heparin and continuous heparin administration after confirming an ACT of 220 s.

Recurrence rates and risk factors in obscure gastrointestinal bleeding

Obscure gastrointestinal bleeding (OGIB), defined in 2010, involves bleeding from the GI tract that remains unexplained after standard diagnostic procedures. OGIB, which accounts for about 5% of all GI bleeds, poses diagnostic and management challenges, particularly due to the anatomical features of the small intestine. Advances in capsule endoscopy (CE) and balloon-assisted endoscopy have improved the diagnostic and therapeutic landscape for small intestinal lesions.

Objective

To determine the recurrence rate and identify risk factors for recurrence following diagnostic and therapeutic interventions using CE and balloon-assisted endoscopy in patients with OGIB.

Methods

A retrospective cohort study at Gifu University Hospital analyzed CE procedures for patients with OGIB from 2008 to 2022. Patients underwent CE with subsequent treatments based on the findings. Statistical analyses, including Kaplan-Meier and Cox proportional hazards models, were used to estimate cumulative recurrence rates and identify recurrence risk factors.

Results

Out of 417 patients, 65.2% had positive CE findings, leading to therapeutic interventions in 16.3% of cases. The cumulative recurrence rates at 12, 24, and 36 months were 4.3%, 9.0%, and 13.9%, respectively. Liver cirrhosis (hazard rate: 4.15, 95% confidence interval 1.88-9.18, p < 0.01) was identified as a significant risk factor for recurrence.

Conclusions

A significant recurrence rate in OGIB patients, with liver cirrhosis being a major risk factor. Despite diagnostic and therapeutic advances, a comprehensive approach including careful follow-up and consideration of risk factors is essential for management.

Is annual screening by fecal immunochemical test necessary after a recent colonoscopy?

Objective

The population-based colorectal cancer screening guidelines in Japan recommend an annual fecal immunochemical test (FIT). However, there is no consensus on the need for annual FIT screening for patients who recently performed a total colonoscopy (TCS). Therefore, we evaluated the repeated TCS results for patients with positive FIT after a recent TCS to assess the necessity of an annual FIT.

Methods

We reviewed patients with positive FIT in opportunistic screening from April 2017 to March 2022. The patients were divided into two groups: those who had undergone TCS within the previous 5 years (previous TCS group) and those who had not (non-previous TCS group). We compared the detection rates of advanced neoplasia and colorectal cancer between the two groups.

Results

Of 671 patients, 151 had received TCS within 5 years and 520 had not. The detection rates of advanced neoplasia in the previous TCS and non-previous TCS groups were 4.6% and 12.1%, respectively (p < 0.01), and the colorectal cancer detection rates were 0.7% and 1.5%, respectively (no significant difference). The adenoma detection rates were 33.8% in the previous TCS group and 40.0% in the non-previous TCS group (no significant difference).

Conclusions

Only a few patients were diagnosed with advanced neoplasia among the patients with FIT positive after a recent TCS. For patients with adenomatous lesions on previous TCS, repeated TCS should be performed according to the surveillance program without an annual FIT. The need for an annual FIT for patients without adenomatous lesions on previous TCS should be prospectively assessed in the future.

Endoscopic detection and diagnosis of gastric cancer using image-enhanced endoscopy: A systematic review and meta-analysis

Objectives

We aimed to conduct a systematic review and meta-analysis to assess the value of image-enhanced endoscopy including blue laser imaging (BLI), linked color imaging, narrow-band imaging (NBI), and texture and color enhancement imaging to detect and diagnose gastric cancer (GC) compared to that of white-light imaging (WLI).

Methods

Studies meeting the inclusion criteria were identified through PubMed, Cochrane Library, and Japan Medical Abstracts Society databases searches. The pooled risk ratio for dichotomous variables was calculated using the random-effects model to assess the GC detection between WLI and image-enhanced endoscopy. A random-effects model was used to calculate the overall diagnostic performance of WLI and magnifying image-enhanced endoscopy for GC.

Results

Sixteen studies met the inclusion criteria. The detection rate of GC was significantly improved in linked color imaging compared with that in WLI (risk ratio, 2.20; 95% confidence interval [CI], 1.39-3.25; p < 0.01) with mild heterogeneity. Magnifying endoscopy with NBI (ME-NBI) obtained a pooled sensitivity, specificity, and area under the summary receiver operating curve of 0.84 (95 % CI, 0.80-0.88), 0.96 (95 % CI, 0.94-0.97), and 0.92, respectively. Similarly, ME-BLI showed a pooled sensitivity, specificity, and area under the curve of 0.81 (95 % CI, 0.77-0.85), 0.85 (95 % CI, 0.82-0.88), and 0.95, respectively. The diagnostic efficacy of ME-NBI/BLI for GC was evidently high compared to that of WLI, However, significant heterogeneity among the NBI studies still existed.

Conclusions

Our meta-analysis showed a high detection rate for linked color imaging and a high diagnostic performance of ME-NBI/BLI for GC compared to that with WLI.

Endoscopic findings and outcomes of gastric mucosal changes relating to potassium-competitive acid blocker and proton pump inhibitor therapy

Gastric mucosal changes associated with long-term potassium-competitive acid blocker and proton pump inhibitor (PPI) therapy may raise concern. In contrast to that for PPIs, the evidence concerning the safety of long-term potassium-competitive acid blocker use is scant. Vonoprazan (VPZ) is a representative potassium-competitive acid blocker released in Japan in 2015. In order to shed some comparative light regarding the outcomes of gastric mucosal lesions associated with a long-term acid blockade, we have reviewed six representative gastric mucosal lesions: fundic gland polyps, gastric hyperplastic polyps, multiple white and flat elevated lesions, cobblestone-like gastric mucosal changes, gastric black spots, and stardust gastric mucosal changes. For these mucosal lesions, we have evaluated the association with the type of acid blockade, patient gender, Helicobacter pylori infection status, the degree of gastric atrophy, and serum gastrin levels. There is no concrete evidence to support a significant relationship between VPZ/PPI use and the development of neuroendocrine tumors. Current data also shows that the risk of gastric mucosal changes is similar for long-term VPZ and PPI use. Serum hypergastrinemia is not correlated with the development of some gastric mucosal lesions. Therefore, serum gastrin level is unhelpful for risk estimation and for decision-making relating to the cessation of these drugs in routine clinical practice. Given the confounding potential neoplastic risk relating to H. pylori infection, this should be eradicated before VPZ/PPI therapy is commenced. The evidence to date does not support the cessation of clinically appropriate VPZ/PPI therapy solely because of the presence of these associated gastric mucosal lesions.

Safety of edoxaban for delayed bleeding in gastrointestinal endoscopic procedures with a high risk of bleeding

Objectives

There are limited reports on the safety of gastrointestinal endoscopic procedures in individuals taking edoxaban, one of the direct oral anticoagulants. We clarified the incidence of delayed bleeding in patients who were on edoxaban in the perioperative period of gastrointestinal endoscopic procedures with a high risk of bleeding.

Methods

This was an investigator-initiated, single-center, open-label, prospective, single-arm study. Patients on warfarin or edoxaban undergoing endoscopy with a high risk of bleeding were enrolled from June 2018 to September 2021. Warfarin was replaced with edoxaban in patients on warfarin. Patients taking other direct oral anticoagulants, and antiplatelet drugs, were excluded. The primary endpoint was severe delayed bleeding (Common Terminology Criteria for Adverse Events [CTCAE] grades III-V) and the secondary endpoints included thromboembolism, all adverse events, any delayed bleeding (CTCAE grades I or II), and hospital stay durations.

Results

Twenty-one patients on edoxaban underwent high-risk endoscopy. Three cases (14%) experienced CTCAE grade III delayed bleeding, requiring endoscopic hemostasis. No CTCAE grade I-II delayed bleeding or thromboembolic events occurred. Cholangitis and aspiration pneumonia (conservatively treated) occurred during the hospital stay. The median length of hospital stay was 8 days (range 3-24 days). Patients with delayed bleeding had higher systolic blood pressure at admission and longer hospital stays.

Conclusions

The delayed bleeding incidence in high-risk endoscopic procedures for patients on edoxaban was acceptable. Higher blood pressure may be associated with increased risk, but further research is needed.

Efficacy and safety of uncovered self-expandable metal stents for distal malignant biliary obstruction in unresectable non-pancreatic cancer

Objectives

The efficacy of uncovered self-expandable metal stents (UCSEMS) versus fully covered self-expandable metal stents for distal malignant biliary obstruction remains controversial. Additionally, the heterogeneity of the disease conditions has been indicated in previous studies because pancreatic and non-pancreatic cancers have different characteristics in clinical course. Therefore, the etiology of biliary obstruction necessitates investigations stratified by primary disease. This study aimed to evaluate the outcomes of UCSEMS, specifically for non-pancreatic cancer-induced distal malignant biliary obstruction.

Methods

We conducted a single-center retrospective review to evaluate the time to recurrent biliary obstruction and frequency of adverse events (AEs) in patients receiving UCSEMS for unresectable non-pancreatic cancer-induced malignant biliary obstruction.

Results

Overall, 32 patients were enrolled in the study between January 2016 and December 2023. The median time to recurrent biliary obstruction was 140 days. AE rates were low at 3.1% for both pancreatitis and cholecystitis, suggesting a potential benefit of UCSEMS in reducing post-procedural AEs.

Conclusion

UCSEMS may reduce the risk of post-procedural AEs and should be considered in patients at high risk of post-endoscopic retrograde cholangiopancreatography pancreatitis. However, the patency period may be shorter, necessitating future comparative research with fully covered self-expandable metal stents to determine the optimal stent choice.

Micro-bacterial assessment of disposable gowns with a focus on green endoscopy in gastrointestinal endoscopy procedures: A Japanese pilot study for healthcare waste reduction

Objective

This study aimed to implement green endoscopy through the microbiological assessment of gowning techniques during endoscopy to reduce carbon emissions and separate medical waste.

Methods

Twenty-five patients who performed esophagogastroduodenoscopy from March to May 2024 were included in this study. Four sections of the isolation gowns (anterior, posterior, right, and left) were cut into 2 cm2 after endoscopy, and the rate of microbial contamination was examined using the stamp method.

Results

The endoscopic examination time was 8 min (6-12), and endoscopy was performed by 10 expert endoscopists, six endoscopists, and nine residents. The overall isolation gown contamination rate was 56%, with 25%, 20.8%, 20.8%, and 33.3% in the front, back, as well as right and left arms, respectively. The rates of isolation gown contamination rates in the expert endoscopists, endoscopists, and residents groups were 30%, 50%, and 77.8%, respectively, with a higher rate in the residents group. Regardless of the physician's performance, bacterial detection was consistently higher in the left arm (42.9% vs. 40% vs. 25%; p = 0.093). The detected bacteria comprised 58% Gram-positive and 42% Gram-negative organisms, including those from tap water used for endoscopy bacteria and obtained from the participant's skin or mouth. No pathogenic organisms were detected.

Conclusions

The bacteria detected in disposable gowns after gastrointestinal endoscopy were non-pathogenic. Thus, our findings suggest that changing all personal protective equipment of respective endoscopes might not be essential. We advocate for green endoscopy to achieve sustainable development goals and reduce medical waste.

Analysis of lens cloudiness during endoscopic submucosal dissection procedures: Effects of a novel lens cleaner

Objectives

We aimed to identify independent factors for intraoperative endoscopic lens cloudiness during gastric and colorectal endoscopic submucosal dissections, investigate the effectiveness of Cleastay, an endoscope anti-fog solution, and examine factors associated with severe submucosal fat deposition.

Methods

A total of 220 patients who underwent gastric or colorectal endoscopic submucosal dissections in two institutions between January 2022 and October 2023 were included. Significant factors related to cloudiness were determined using univariate and multivariate analyses. Patient background and tumor characteristics related to severe submucosal fat deposition were investigated, and the degree of intraoperative endoscopic lens cloudiness and outcomes were compared between the Cleash and Cleastay groups.

Results

In the multivariate analysis, factors increasing lens cloudiness included long procedure time (odds ratio [OR], 17.51; 95% confidence interval [CI], 1.52-202.08), stomach (vs. colon; OR, 5.08; 95% CI, 1.99-12.96), and severe submucosal fat deposition (OR, 12.19; 95% CI, 5.02-29.60). Conversely, the use of Cleastay (vs. Cleash; OR, 0.066; 95% CI, 0.021-0.21) was identified as a factor reducing cloudiness. Location analysis revealed that severe submucosal fat deposition was more common in the upper stomach and right colon.

Conclusions

It was suggested that Cleastay is more useful for endoscopic submucosal dissection of the upper stomach and right colon, where severe submucosal fat deposition is expected.

Risk factors for biliary tract events during elective cholecystectomy waiting time after endoscopic retrograde cholangiopancreatography for choledocholithiasis

Objectives

Endoscopic lithotripsy and elective cholecystectomy, followed by endoscopic retrograde cholangiopancreatography, are the first-line treatments for patients with common bile duct (CBD) stones (CBDS) and gallstones. However, this approach entails acute cholecystitis and recurrent cholangitis risk while patients await surgery. We aimed to identify acute cholecystitis and cholangitis risk factors during the waiting time for elective cholecystectomy.

Methods

This study comprised 151 patients with CBDS combined with gallstones who underwent cholecystectomy within 90 days of the first endoscopic retrograde cholangiopancreatography at two tertiary care centers between January 2019 and October 2021.

Results

The incidence of biliary tract events (acute cholecystitis, acute cholangitis, or any complications requiring unplanned cholangiopancreatography) was 28% (43 cases). In univariate and multivariate analyses, plastic stent placement as a bridge to surgery for the first treatment of CBDS was an independent risk factor for biliary tract events during the waiting time for surgery (odds ratio 4.25, p = 0.002). A subgroup analysis among those with plastic stent placement revealed a CBD diameter of ≤ 10 mm as an independent risk factor for acute cholecystitis (odds ratio 4.32; p = 0.027); a CBD diameter ≥ 11 mm was an independent risk factor for acute cholangitis and unplanned re-endoscopic retrograde cholangiopancreatography (odds ratio 5.66; p = 0.01).

Conclusions

Plastic stent placement for CBDS before elective cholecystectomy increases the risk of acute cholecystitis or acute cholangitis during the waiting time for elective cholecystectomy.

Current status of endoscopic ultrasound in the diagnosis of intraductal papillary mucinous neoplasms

The new Kyoto guidelines for the management of intraductal papillary mucinous neoplasm (IPMN) provide evidence-based recommendations for the diagnosis and treatment of IPMN. Endoscopic ultrasonography (EUS) is a diagnostic modality with a high spatial resolution that allows detailed observation and obtaining cyst fluid or tissue samples via EUS-guided fine needle aspiration (EUS-FNA). Currently, EUS is an indispensable examination method for the diagnosis of pancreatic diseases. On the other hand, there have been concerns that EUS imaging tends to be highly operator-dependent, and may lack objectivity. Previous guidelines have assigned EUS as an option for patients with worrisome features. However, recent reports indicate that the sensitivity of EUS for the diagnosis of mural nodules (MNs) is more than 90%, comparable or superior to that of contrast-enhanced computed tomography or magnetic resonance cholangiopancreatography. The specific advantages of EUS in the diagnosis of IPMN are: (1) high spatial resolution imaging for the diagnosis of MNs, (2) contrast-enhanced EUS for differentiation of intra-cystic MNs from mucous clots, and (3) pathological diagnosis using EUS-FNA and differential diagnosis of a pancreatic cystic tumor by cystic fluid analysis. In order to utilize EUS in the diagnosis of IPMN, endoscopists are required to have the skills to provide sufficiently objective imaging findings.

Colorectal endoscopic submucosal dissection in the USA: The current state and future perspectives

Endoscopic submucosal dissection (ESD) is a transformative advancement in the endoscopic management of superficial gastrointestinal lesions. Initially conceived for the treatment of early gastric cancer, ESD has demonstrated proficiency in achieving en-bloc resection of superficial gastrointestinal lesions. ESD has experienced widespread acceptance in Japan and East Asia; however, its adoption in the USA remains delayed. This initial hesitancy could be attributed to procedural complexity and training demands; nonetheless, recently, ESD has been gaining popularity in the USA. This is due to the advancements in endoscopic technology, tailored training programs, and cumulative evidence regarding the efficacy and safety of ESDs. This review aimed to deliberate the historical progress, current implementation, and prospective trajectory of ESDs in the USA. With ongoing clinical research, technological integration, and educational efforts, ESD is likely to become the gold standard for managing large gastrointesitinal lesions. This progress marks an imperative step toward less invasive, more precise, and patient-centric approaches regarding advanced therapeutic endoscopy in the USA.