Perspectives on label-free microscopy of heterogeneous and dynamic biological systems

Significance

Advancements in label-free microscopy could provide real-time, non-invasive imaging with unique sources of contrast and automated standardized analysis to characterize heterogeneous and dynamic biological processes. These tools would overcome challenges with widely used methods that are destructive (e.g., histology, flow cytometry) or lack cellular resolution (e.g., plate-based assays, whole animal bioluminescence imaging).

Aim

This perspective aims to (1) justify the need for label-free microscopy to track heterogeneous cellular functions over time and space within unperturbed systems and (2) recommend improvements regarding instrumentation, image analysis, and image interpretation to address these needs.

Approach

Three key research areas (cancer research, autoimmune disease, and tissue and cell engineering) are considered to support the need for label-free microscopy to characterize heterogeneity and dynamics within biological systems. Based on the strengths (e.g., multiple sources of molecular contrast, non-invasive monitoring) and weaknesses (e.g., imaging depth, image interpretation) of several label-free microscopy modalities, improvements for future imaging systems are recommended.

Conclusion

Improvements in instrumentation including strategies that increase resolution and imaging speed, standardization and centralization of image analysis tools, and robust data validation and interpretation will expand the applications of label-free microscopy to study heterogeneous and dynamic biological systems.

Deformability of Heterogeneous Red Blood Cells in Aging and Related Pathologies

Aging is interrelated with changes in red blood cell parameters and functionality. In this article, we focus on red blood cells (RBCs) and provide a review of the known changes associated with the characterization of RBC deformability in aging and related pathologies. The biophysical parameters complement the commonly used biochemical parameters and may contribute to a better understanding of the aging process. The power of the deformability measurement approach is well established in clinical settings. Measuring RBCs' deformability has the advantage of relative simplicity, and it reflects the complex effects developing in erythrocytes during aging. However, aging and related pathological conditions also promote heterogeneity of RBC features and have a certain impact on the variance in erythrocyte cell properties. The possible applications of deformability as an early biophysical biomarker of pathological states are discussed, and modulating PIEZO1 as a therapeutic target is suggested. The changes in RBCs' shape can serve as a proxy for deformability evaluation, leveraging single-cell analysis with imaging flow cytometry and artificial intelligence algorithms. The characterization of biophysical parameters of RBCs is in progress in humans and will provide a better understanding of the complex dynamics of aging.

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.

Steroid lifting method during endoscopic submucosal dissection: A novel strategy for stricture prevention

A 73-year-old male patient was referred to us with a long Barrett's esophagus (BE). He had a history of pulmonary embolism under anticoagulant therapy. Esophagogastroduodenoscopy showed a C8M9 BE with no macroscopic lesions. Random biopsies from the BE revealed multifocal high-grade dysplasia. The case was discussed in a multidisciplinary team conference and the decision for full resection of BE with endoscopic submucosal dissection (ESD) was made. Considering the large ESD resection and the high risk of stricture, we developed a novel preventive technique: the "steroid lifting method" for submucosal injection during ESD. Complete circumferential ESD with en bloc resection was performed using the "steroid lifting method", without adverse events. Oral liquids were initiated on day 1 and the patient was discharged on day 4. Oral prednisolone (30 mg per day) was started and tapered for a total of 6 weeks. The pathological examination confirmed multifocal high-grade dysplasia, with radical and curative resection. The patient had neither stricture, dysphagia nor recurrence of Barrett's mucosa at the 2, 6, 12, and 24-month follow-up. International guidelines recommend oral prednisolone and triamcinolone injection to prevent stricture formation in large ESD of esophageal squamous cell carcinoma. However, there is no solid data on BE ESD. The risk factors for stricture formation and the optimal preventive management after large BE ESD is not known. The "steroid lifting method" might be an option in this context. Large prospective studies addressing stricture formation and preventive measures on BE ESD are necessary.

Balloon catheter-assisted endoscopic resection for papillary adenoma of non-exposed protruded type (with video)

Papillary adenomas, known precursors to papillary adenocarcinoma, warrant close monitoring due to their malignant potential. Historically, surgical resection represented the mainstay of treatment for papillary adenomas with intraductal extension. However, recent advancements in endoscopic techniques have facilitated the adoption of endoscopic papillectomy as a minimally invasive alternative in carefully selected cases. We report a case of an 82-year-old woman with a diagnosis of papillary adenoma exhibiting intraductal extension. This was managed with a novel endoscopic technique, balloon catheter-assisted endoscopic resection. Due to the obscured intraductal component of the papillary mass, a balloon occlusion catheter was deployed within the common bile duct and used as traction to facilitate endoscopic visualization of the mass. Endoscopic resection via papillectomy was subsequently performed. Histopathological examination of the resected specimen revealed a villous adenoma with high-grade dysplasia. Serial endoscopic ultrasound examinations with targeted papillary biopsies were performed to monitor for disease recurrence.

Role of metabolic dysfunction and inflammation along the liver-brain axis in animal models with obesity-induced neurodegeneration

The interaction between metabolic dysfunction and inflammation is central to the development of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Obesity-related conditions like type 2 diabetes and non-alcoholic fatty liver disease exacerbate this relationship. Peripheral lipid accumulation, particularly in the liver, initiates a cascade of inflammatory processes that extend to the brain, influencing critical metabolic regulatory regions. Ceramide and palmitate, key lipid components, along with lipid transporters lipocalin-2 and apolipoprotein E, contribute to neuroinflammation by disrupting blood-brain barrier integrity and promoting gliosis. Peripheral insulin resistance further exacerbates brain insulin resistance and neuroinflammation. Preclinical interventions targeting peripheral lipid metabolism and insulin signaling pathways have shown promise in reducing neuroinflammation in animal models. However, translating these findings to clinical practice requires further investigation into human subjects. In conclusion, metabolic dysfunction, peripheral inflammation, and insulin resistance are integral to neuroinflammation and neurodegeneration. Understanding these complex mechanisms holds potential for identifying novel therapeutic targets and improving outcomes for neurodegenerative diseases.

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.

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.

Unilateral drainage and chemotherapy prolong the patency of a plastic stent placed above the sphincter of Oddi in patients with malignant hilar biliary obstruction

Objectives

To evaluate the results of inside stent therapy for unresectable malignant hilar biliary obstruction and identify factors related to stent patency duration.

Methods

Of 44 patients who underwent initial inside-stent placement above the sphincter of Oddi from April 2017 to December 2022, 42 with the resolution of jaundice (clinical success rate, 95.5%) were retrospectively analyzed. Univariate and multivariate logistic regression analysis identified factors associated with stent patency duration.

Results

Univariate analysis revealed significant differences in the drainage method (406 days for unilateral drainage vs. 305 days for bilateral drainage of the right and left liver lobes, p = 0.022) with or without chemotherapy (406 days with vs. 154 days without, p = 0.038). Multivariate analysis (Cox proportional hazards analysis) revealed similar results, with unilateral drainage (p = 0.031) and chemotherapy (p = 0.048) identified as independent factors associated with prolonged stent patency. Early adverse events were observed in two patients (4.8%; one cholangitis, one pancreatitis).

Conclusions

Inside-stent therapy was safely performed in patients with malignant hilar biliary obstruction. Simple unilateral drainage and chemotherapy may prolong stent patency.

The influence of color vision deficiency on vessel visibility during colorectal endoscopic submucosal dissection and the potential advantage of red dichromatic imaging to achieve color vision barrier-free

Objectives

Although color information is important in gastrointestinal endoscopy, there are limited studies on how endoscopic images are viewed by people with color vision deficiency. We aimed to investigate the differences in the visibility of blood vessels during endoscopic submucosal dissection (ESD) among people with different color vision characteristics and to examine the effect of red dichromatic imaging (RDI) on blood vessel visibility.

Methods

Seventy-seven pairs of endoscopic images of white light imaging (WLI) and RDI of the same site were obtained during colorectal ESD. The original images were set as type C (WLI-C and RDI-C), a common color vision. These images were computationally converted to simulate images perceived by people with color vision deficiency protanope (Type P) or deutanope (Type D) and denoted as WLI-P and RDI-P or WLI-D and RDI-D. Blood vessels and background submucosa that needed to be identified during ESD were selected in each image, and the color differences between these two objects were measured using the color difference (ΔE 00) to assess the visibility of blood vessels.

Results

ΔE 00 between a blood vessel and the submucosa was greater under RDI (RDI-C/P/D: 24.05 ± 0.64/22.85 ± 0.66/22.61 ± 0.64) than under WLI (WLI-C/P/D: 22.26 ± 0.60/5.19 ± 0.30/8.62 ± 0.42), regardless of color vision characteristics. This improvement was more pronounced in Type P and Type D and approached Type C in RDI.

Conclusions

Color vision characteristics affect the visibility of blood vessels during ESD, and RDI improves blood vessel visibility regardless of color vision characteristics.

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.

Perfluoropentane-based oxygen-loaded nanodroplets reduce microglial activation through metabolic reprogramming

JOURNAL/nrgr/04.03/01300535-202504000-00032/figure1/v/2024-07-06T104127Z/r/image-tiff Microglia, the primary immune cells within the brain, have gained recognition as a promising therapeutic target for managing neurodegenerative diseases within the central nervous system, including Parkinson's disease. Nanoscale perfluorocarbon droplets have been reported to not only possess a high oxygen-carrying capacity, but also exhibit remarkable anti-inflammatory properties. However, the role of perfluoropentane in microglia-mediated central inflammatory reactions remains poorly understood. In this study, we developed perfluoropentane-based oxygen-loaded nanodroplets (PFP-OLNDs) and found that pretreatment with these droplets suppressed the lipopolysaccharide-induced activation of M1-type microglia in vitro and in vivo, and suppressed microglial activation in a mouse model of Parkinson's disease. Microglial suppression led to a reduction in the inflammatory response, oxidative stress, and cell migration capacity in vitro. Consequently, the neurotoxic effects were mitigated, which alleviated neuronal degeneration. Additionally, ultrahigh-performance liquid chromatography-tandem mass spectrometry showed that the anti-inflammatory effects of PFP-OLNDs mainly resulted from the modulation of microglial metabolic reprogramming. We further showed that PFP-OLNDs regulated microglial metabolic reprogramming through the AKT-mTOR-HIF-1α pathway. Collectively, our findings suggest that the novel PFP-OLNDs constructed in this study alleviate microglia-mediated central inflammatory reactions through metabolic reprogramming.

Clinical assessment of computed tomography for detecting ingested blister packs: A single-center retrospective study

Objectives

Blister pack (BP) ingestion poses serious risks, such as gastrointestinal perforation, and accurate localization by computed tomography (CT) is a common practice. However, while it has been reported in vitro that CT visibility varies with the material type of BPs, there have been no reports on this variability in clinical settings. In this study, we investigated the CT detection rates of different BPs in clinical settings.

Methods

This single-center retrospective study from 2010 to 2022 included patients who underwent endoscopic foreign body removal for BP ingestion. The patients were categorized into two groups for BP components, the polypropylene (PP) and the polyvinyl chloride (PVC)/polyvinylidene chloride (PVDC) groups. The primary outcome was the comparison of CT detection rates between the groups. We also evaluated whether the BPs contained tablets and analyzed their locations.

Results

This study included 61 patients (15 in the PP group and 46 in the PVC/PVDC group). Detection rates were 97.8% for the PVC/PVDC group compared to 53.3% for the PP group, a significant difference (p < 0.01). No cases of BPs composed solely of PP were detected by CT. Blister packs were most commonly found in the upper thoracic esophagus.

Conclusions

Even in a clinical setting, the detection rates of PVC and PVDC were higher than that of PP alone. Identifying PP without tablets has proven challenging in clinical. Considering the risk of perforation, these findings suggest that esophagogastroduodenoscopy may be necessary, even if CT detection is negative.

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.

Comparison of propofol-based sedation and midazolam sedation in pediatric bidirectional endoscopy conducted by pediatric gastroenterologists

Objectives

The effectiveness and safety of propofol-based sedation and midazolam sedation in pediatric bidirectional endoscopy were compared.

Methods

We retrospectively analyzed the cases of pediatric patients (≤15 years old) who had undergone bidirectional endoscopy, esophagogastroduodenoscopy, and colonoscopy by pediatric gastroenterologists. Demographic data, indications, sedatives/dosages, clinical outcomes, endoscopic findings, adverse events, and total patient time requirements (total time in which patients stay in our hospital) were compared in the two sedation groups.

Results

Ninety-one children (51 boys, 40 girls, mean age 13 years, range 9-15) treated at our hospital were enrolled. Propofol alone or in combination with midazolam and/or pentazocine was administered to 51 patients (propofol-based sedation group). Midazolam alone or in combination with pentazocine was administered to the other 40 patients (midazolam sedation group). In the propofol group, the following mean doses were used: propofol, 96 mg (range 40-145 mg); midazolam, 4.9 mg (range 3-5 mg); and pentazocine, 7.5 mg. In the midazolam group, the mean doses of midazolam and pentazocine were 6.2 mg (range 4-10 mg) and 15 mg, respectively. All procedures were successfully completed by pediatric gastroenterologists. The total procedure times and endoscopic findings were similar in the two groups, but the median patient time requirement in the propofol group was significantly shorter versus the midazolam group (7.3 h vs. 8.4 h, p < 0.001). No adverse events occurred in either group.

Conclusions

Propofol-based sedation in pediatric bidirectional endoscopy was safely and effectively performed by pediatric gastroenterologists, and its patient time requirement was shorter than that for midazolam sedation.

Gastrointestinal endoscopy training in the United States: Program structure and competence assessment

The general principles of gastrointestinal endoscopy training in the United States were formulated and summarized more than a decade ago and the principles have been consistent until now. To summarize, trainees should be prepared to (i) appropriately recommend endoscopic procedures as indicated by the findings of the consultative evaluation, with an explicit understanding of accepted specific indications, contraindications, and diagnostic/therapeutic alternatives, (ii) perform procedures safely, completely, and expeditiously, including possessing a thorough understanding of the principles of conscious sedation/analgesia techniques, the use of anesthesia-assisted sedation where appropriate, and pre-procedure clinical assessment and patient monitoring, (iii) correctly interpret endoscopic findings and integrate them into medical or endoscopic therapy, (iv) identify risk factors for each procedure, understand how to minimize each, and recognize and appropriately manage complications when they occur, (v) acknowledge the limitations of endoscopic procedures and personal skills and know when to request help, and (vi) understand the principles of quality measurement and improvement. This article provides an overview of the endoscopy training system and structure, evaluation scheme, and competence and credentialing process in the United States.

Treating amyotrophic lateral sclerosis with allogeneic Schwann cell-derived exosomal vesicles: a case report

Schwann cells are essential for the maintenance and function of motor neurons, axonal networks, and the neuromuscular junction. In amyotrophic lateral sclerosis, where motor neuron function is progressively lost, Schwann cell function may also be impaired. Recently, important signaling and potential trophic activities of Schwann cell-derived exosomal vesicles have been reported. This case report describes the treatment of a patient with advanced amyotrophic lateral sclerosis using serial intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles, marking, to our knowledge, the first instance of such treatment. An 81-year-old male patient presented with a 1.5-year history of rapidly progressive amyotrophic lateral sclerosis. After initial diagnosis, the patient underwent a combination of generic riluzole, sodium phenylbutyrate for the treatment of amyotrophic lateral sclerosis, and taurursodiol. The patient volunteered to participate in an FDA-approved single-patient expanded access treatment and received weekly intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles to potentially restore impaired Schwann cell and motor neuron function. We confirmed that cultured Schwann cells obtained from the amyotrophic lateral sclerosis patient via sural nerve biopsy appeared impaired (senescent) and that exposure of the patient's Schwann cells to allogeneic Schwann cell-derived exosomal vesicles, cultured expanded from a cadaver donor improved their growth capacity in vitro. After a period of observation lasting 10 weeks, during which amyotrophic lateral sclerosis Functional Rating Scale-Revised and pulmonary function were regularly monitored, the patient received weekly consecutive infusions of 1.54 × 10 12 (×2), and then consecutive infusions of 7.5 × 10 12 (×6) allogeneic Schwann cell-derived exosomal vesicles diluted in 40 mL of Dulbecco's phosphate-buffered saline. None of the infusions were associated with adverse events such as infusion reactions (allergic or otherwise) or changes in vital signs. Clinical lab serum neurofilament and cytokine levels measured prior to each infusion varied somewhat without a clear trend. A more sensitive in-house assay suggested possible inflammasome activation during the disease course. A trend for clinical stabilization was observed during the infusion period. Our study provides a novel approach to address impaired Schwann cells and possibly motor neuron function in patients with amyotrophic lateral sclerosis using allogeneic Schwann cell-derived exosomal vesicles. Initial findings suggest that this approach is safe.

Hypoxia-preconditioned bone marrow-derived mesenchymal stem cells protect neurons from cardiac arrest-induced pyroptosis

JOURNAL/nrgr/04.03/01300535-202504000-00027/figure1/v/2024-07-06T104127Z/r/image-tiff Cardiac arrest can lead to severe neurological impairment as a result of inflammation, mitochondrial dysfunction, and post-cardiopulmonary resuscitation neurological damage. Hypoxic preconditioning has been shown to improve migration and survival of bone marrow-derived mesenchymal stem cells and reduce pyroptosis after cardiac arrest, but the specific mechanisms by which hypoxia-preconditioned bone marrow-derived mesenchymal stem cells protect against brain injury after cardiac arrest are unknown. To this end, we established an in vitro co-culture model of bone marrow-derived mesenchymal stem cells and oxygen-glucose deprived primary neurons and found that hypoxic preconditioning enhanced the protective effect of bone marrow stromal stem cells against neuronal pyroptosis, possibly through inhibition of the MAPK and nuclear factor κB pathways. Subsequently, we transplanted hypoxia-preconditioned bone marrow-derived mesenchymal stem cells into the lateral ventricle after the return of spontaneous circulation in an 8-minute cardiac arrest rat model induced by asphyxia. The results showed that hypoxia-preconditioned bone marrow-derived mesenchymal stem cells significantly reduced cardiac arrest-induced neuronal pyroptosis, oxidative stress, and mitochondrial damage, whereas knockdown of the liver isoform of phosphofructokinase in bone marrow-derived mesenchymal stem cells inhibited these effects. To conclude, hypoxia-preconditioned bone marrow-derived mesenchymal stem cells offer a promising therapeutic approach for neuronal injury following cardiac arrest, and their beneficial effects are potentially associated with increased expression of the liver isoform of phosphofructokinase following hypoxic preconditioning.

Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion

JOURNAL/nrgr/04.03/01300535-202504000-00033/figure1/v/2024-07-06T104127Z/r/image-tiff Behavioral recovery using (viable) peripheral nerve allografts to repair ablation-type (segmental-loss) peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration. Furthermore, such peripheral nerve allografts undergo immunological rejection by the host immune system. In contrast, peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks, reduced immune responses, and many axons do not undergo Wallerian degeneration. The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study. We hypothesized that polyethylene glycol might have some immune-protective effects, but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery. We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion. Ablation-type sciatic nerve injuries in outbred Sprague-Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts, but peripheral nerve allografts were loose-sutured (loose-sutured polyethylene glycol) with an intentional gap of 1-2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons. Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts, animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively. Other morphological signs of rejection, such as collapsed Schwann cell basal lamina tubes, were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively. Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts. While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts, loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively. MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts, but MHCII expression was modestly lower compared to negative control at 21 days postoperatively. We conclude that, while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts, successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts, and produce recovery of sensory/motor functions and voluntary behaviors. Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.

Clinical usefulness and acceptability of small-bowel capsule endoscopy with panoramic imaging compared with axial imaging in Japanese patients

Objectives

We aimed to evaluate the usefulness and acceptability of CapsoCam Plus (CapsoCam) in Japanese patients.

Methods

This retrospective single-center study enrolled 930 patients with suspected small-bowel bleeding (SSBB) who underwent capsule endoscopy. Thirty-three patients using CapsoCam and PillCam SB3 (SB3) were matched using propensity score matching. The diagnostic yield and the acceptability of CapsoCam were evaluated.

Results

There was no SSBB case where capsule endoscopy was performed within 48 h of bleeding. CapsoCam had a significantly higher observation rate of the entire small bowel (97% vs. 73%, p = 0.006) and Vater's papilla (82% vs. 15%, p < 0.001) than SB3. The reading time of CapsoCam was significantly longer than that of SB3 (30 vs. 25 min, p < 0.001), and CapsoCam's time from the capsule endoscopy swallowing to read completion was longer than that of SB3 (37 vs. 12 h, p < 0.001). The two groups showed no difference in the capsule endoscopy findings according to the P classification. Notably, 85% of the patients using CapsoCam reported examination distress as "not at all" or "almost not," and 94% reported swallowing difficulty as "very easy" or "easy."

Conclusions

CapsoCam took time to read; however, it is a well-tolerated examination with a high observation rate of Vater's papilla and entire small-bowel mucosa. Detectability of bleeding sources was comparable in both modalities for cases of occult SSBB and overt SSBB more than 48 h after bleeding. CapsoCam is a useful modality for patients with SSBB.