Citations

AbstractBackgroundTau aggregation is the underlying cause of several neurodegenerative tauopathies. Formation of tau aggregates with seeding activity involves interactions with other proteins, but with unknown effects on tau‐seed properties. Our previous study found that Bassoon (BSN), a presynaptic protein, interacts with tau‐seed, exacerbating its toxicity in vivo. Bsn downregulation reduced tau spreading and overall pathology. A previous study also linked missense mutations in BSN to the aggregation of 3‐ and 4‐repeat tau in patients. However, it is unknown how genetic mutations in BSN influence tau pathology in vivo.MethodWe developed a knock‐in mouse model harboring a mutation in endogenous BSN (p.Pro3882Ala), equivalent to p.Pro3866Ala BSN mutation identified in patients. We evaluated the cognitive and motor abilities of aged heterozygous and homozygous BSNKI mice and also we analyzed BSN and tau patterns in the brains of these mice. Additionally, we examined BSN and tau patterns in the BSN mutation carrier.ResultAt 10 months, BSNKI mice did not exhibit anxiety‐related behavior and had similar activity as WT littermates. They also displayed similar cognitive abilities as the WT mice. Interestingly, the BSNKI mice displayed lower latency to fall off the rotarod and reduced grip strength compared to the WT mice. We also observed an increase in the accumulation of pathological tau and BSN deposits in the brains of the BSNKI mice. The BSN mutation carrier displayed inclusions of BSN and tau pathology.ConclusionWe developed a mouse model with a knock‐in mutation in the Bassoon gene, allowing us to evaluate the effects of this disease‐associated mutation in vivo. Our results have shown that the mice with Bsn mutation have impairments in motor coordination, and postural instability, similar to BSN mutation carriers and show pathological tau and BSN deposits in the brain. We found inclusions of BSN and tau pathology in BSN mutation the carrier that resembled certain pathological features of AD and PSP. These findings suggest that BSN plays a role in tau pathology and targeting it may represent a promising therapeutic strategy for tauopathies. Further research is needed to fully understand our findings' underlying mechanisms and potential therapeutic implications.

Introduction/Background: Cardiopulmonary arrest (Code Blue or CB) is a feared complication of severe medical illnesses. In-hospital CB events (CBE) have been estimated to have a mortality rate of only 30.4%. CBEsare difficult to prepare for and execute due many factors, including their low frequency, high complexity, and unpredictability. Research Questions/Hypothesis: Over 6 months (March - September 2019), we tested the effects of both adaptation of a Code Blue (CB) Team Leader (TL) checklist—aimed at improving resident leadership and communication—as well as implementation of an interdisciplinary in-hospital CB simulation to improve the performance of both resident physicians. Methods/Approach: Primary outcomes included change in resident confidence leading a CBE (i.e. Level of comfort as TL , confidence of diagnosis and management, confidence in code-related procedural skills), and familiarity with the institutional rapid response protocol. Secondary outcomes included self-reported confidence of nurses to execute their role, and both physician and nurse time to response. Confidence parameters were measured by a 10 point Likert scale. Pre-intervention, baseline cross-sectional survey values of the primary outcome were obtained from 24 internal medicine residents (12 PGY2s, 12 PGY3) over 6 months. Post-intervention, the cross-sectional survey was repeated. Results/Data (descriptive and inferential statistics): Statistics for residents displayed in table and figure 1. The level of nurse confidence increased from 7.5 to 8.25 over 5 months. The time to first response by residents has decreased by more than 50%. Conclusion(s) Our project improved the quality and resident level of comfort running Code Blue events among both residents and nurses.

Abstract Background The BioFire® FilmArray® Gastrointestinal Pathogen Panel (GIPP) tests for 22 potential pathogens in stool, including Clostridioides difficile. C. difficile nucleic acid is detected via nested polymerase chain reaction (PCR) targeting toxin A (TcdA) and/or toxin B (TcdB) genes. While PCR-based diagnostic methods are highly sensitive, they lack specificity to differentiate colonization from C. difficile infection (CDI). Mayo Clinic Arizona (MCA) uses enzyme immunoassay (EIA) testing for toxin A/B and glutamate dehydrogenase antigens with reflex to PCR for discordance as the primary algorithm for diagnosing CDI; however, GIPP PCR testing circumvents this algorithm. When used in patients with low pretest probability for CDI, clinical false positives can lead to inappropriate diagnosis and treatment of colonization. GIPA Results in the Electronic Medical Record Pre-Intervention MCA Standalone C. difficile Testing Algorithm Abbreviations – EIA, enzyme immunoassay; GDH, glutamate dehydrogenase; NAAT, nucleic acid amplification test Methods We convened a multidisciplinary quality improvement team to reduce the detection and treatment of C. difficile colonization secondary to GIPP test results. Surveys were sent to providers and nurses as part of a formal gap analysis and included questions around ordering patterns, knowledge of appropriate tests, and associated costs. Baseline data was compiled from GIPP orders in MCA from 1/1/2022-9/30/2022. Results There were 1978 GIPP orders for 1694 patients during the study period (∼7 GIPPs/day). Most orders (65%) originated from ambulatory settings. The most common positive target was C. difficile (355/723, 49%), which resulted in treatment for suspected CDI in 94.9% (337/355) of cases. Of the 49 providers who responded to the survey, 86% ordered the GIPP at least monthly. Testing for C. difficile was the 2nd most common reason for ordering the GIPP. Most providers underestimated the cost of the panel and were unfamiliar with the differences between the GIPP and EIA testing algorithm. Nurses sought clarification on stool samples suitable for GIPP testing. Following education and modifications to ordering in the electronic health record, the decision was made to remove the C. difficile target from the GIPP. Provider Understanding of C. difficile Testing Methods GIPA Results in the Electronic Medical Record Post-Intervention Conclusion Multiplex PCR panels are comprehensive but require careful implementation to facilitate diagnostic stewardship. Facilities with robust standalone C. difficile testing algorithms may consider removing the C. difficile target from the GIPP. Disclosures All Authors: No reported disclosures

Processing grief from the outside. How a pharmacist experiences patient loss.

Abstract Microglia-mediated neuroinflammation contributes to acute demyelination in neuromyelitis optica spectrum disorders (NMOSD). Soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in the CSF has been associated with microglial activation in several neurodegenerative diseases. However, the basis for this immune-mediated attack and the pathophysiological role of sTREM2 in NMOSD remain to be elucidated. Here, we performed Mendelian randomization analysis and identified a genetic association between increased CSF sTREM2 and NMOSD risk. CSF sTREM2 was elevated in patients with NMOSD and was positively correlated with neural injury and other neuroinflammation markers. Single-cell RNA sequencing of human macrophage/microglia-like cells in CSF, a proxy for microglia, showed that increased CSF sTREM2 was positively associated with microglial dysfunction in patients with NMOSD. Furthermore, we demonstrated that sTREM2 is a reliable biomarker of microglial activation in a mouse model of NMOSD. Using unbiased transcriptomic and lipidomic screens, we identified that excessive activation, overwhelmed phagocytosis of myelin debris, suppressed lipid metabolism and enhanced glycolysis underlie sTREM2-mediated microglial dysfunction, possibly through the nuclear factor kappa B (NF-κB) signalling pathway. These molecular and cellular findings provide a mechanistic explanation for the genetic association between CSF sTREM2 and NMOSD risk and indicate that sTREM2 could be a potential biomarker of NMOSD progression and a therapeutic target for microglia-mediated neuroinflammation.

AbstractBackgroundParticipation in colonoscopies is an essential aspect of endoscopic training. The purpose of this study was to explore the impact of fellow/trainee participation on colonoscopy outcomes.MethodsThis meta‐analysis was registered on the International Prospective Register of Systematic Reviews (PROSPERO). From database inception to July 2022, studies investigating fellow involvement and colonoscopy outcomes were searched across Cochrane library, PubMed, and other databases. The random‐effects model was applied to generate more conservative estimates. Sensitive analysis was conducted to explore whether the result would depend on a particular study. Egger's test and Begg's test were used to estimate the potential for publication bias.ResultsSeventeen studies including 30,062 participants were included. We found that fellow/trainee involvement enhanced the overall rates of adenoma detection and polyp detection (OR = 1.26, 95% CI = 1.14–1.40, p < 0.001; OR = 1.29, 95% CI = 1.02–1.63, p = 0.020, respectively). The mean number of adenoma/polyps per colonoscopy was also higher with fellow/trainee participation (MD = 0.12, 95% CI = 0.08–0.17, p < 0.001; MD = 0.15, 95% CI = 0.02–0.28, p = 0.020, respectively).ConclusionIn addition to its educational purpose, fellow or trainee involvement is associated with beneficial effects on colonoscopy outcomes.

Neuron-derived extracellular vesicles (NDEVs) are potential biomarkers of neurological diseases although their reliable molecular target is not well established. Here, we demonstrate that ATPase Na + /K + transporting subunit alpha 3 (ATP1A3) is abundantly expressed in extracellular vesicles (EVs) isolated from induced human neuron, brain, cerebrospinal fluid, and plasma in comparison with the presumed NDEV markers NCAM1 and L1CAM by using super-resolution microscopy and biochemical assessments. Proteomic analysis of immunoprecipitated ATP1A3 + brain-derived EVs shows higher enrichment of synaptic markers and cargo proteins relevant to Alzheimer’s disease (AD) compared to NCAM1 + or LICAM + EVs. Single particle analysis shows the elevated amyloid-β positivity in ATP1A3 + EVs from AD plasma, providing better diagnostic prediction of AD over other plasma biomarkers. Thus, ATP1A3 is a reliable target to isolate NDEV from biofluids for diagnostic research.

Abstract Extracellular vesicles (EVs) have emerged as critical mediators of intercellular communication and promising biomarkers and therapeutics in the central nervous system (CNS). Human brain‐derived EVs (BDEVs) provide a comprehensive snapshot of physiological changes in the brain's environment, however, the isolation of BDEVs and the comparison of different methods for this purpose have not been fully investigated. In this study, we compared the yield, morphology, subtypes and protein cargo composition of EVs isolated from the temporal cortex of aged human brains using three established separation methods: size‐exclusion chromatography (SEC), phosphatidylserine affinity capture (MagE) and sucrose gradient ultracentrifugation (SG‐UC). Our results showed that SG‐UC method provided the highest yield and collected larger EVs compared to SEC and MagE methods as assessed by transmission electron microscopy and nanoparticle tracking analysis (NTA). Quantitative tandem mass‐tag (TMT) mass spectrometry analysis of EV samples from three different isolation methods identified a total of 1158 proteins, with SG‐UC showing the best enrichment of common EV proteins with less contamination of non‐EV proteins. In addition, SG‐UC samples were enriched in proteins associated with ATP activity and CNS maintenance, and were abundant in neuronal and oligodendrocytic molecules. In contrast, MagE samples were more enriched in molecules related to lipoproteins, cell‐substrate junction and microglia, whereas SEC samples were highly enriched in molecules related to extracellular matrix, Alzheimer's disease and astrocytes. Finally, we validated the proteomic results by performing single‐particle analysis using the super‐resolution microscopy and flow cytometry. Overall, our findings demonstrate the differences in yield, size, enrichment of EV cargo molecules and single EV assay by different isolation methods, suggesting that the choice of isolation method will have significant impact on the downstream analysis and protein discovery.

Abstract Alopecia areata (AA) is the most frequent form of an organ-specific autoimmune disease in humans mediated by NKG2D+ CD8 T cells destroying hair follicles. C3H/HeJ mice naturally develop AA similar to humans, and we found it accompanies the expansion of exhausted phenotype (CD101+ Tim3+) memory CD8 T cells not only in the skin and skin-draining lymph nodes (SDLNs), but also in the liver and lungs. Before the disease induction, we found these CD8 T cells are activated in the lungs and liver, suggesting they are pre-activated in these organs. In the skin, expanded CD8 T cells additionally upregulated CD39, PD-1, and CTLA-4, which produced less IFNg than those in the SDLN, liver and lungs when stimulated. These features suggest that autoreactive CD8 T cells in the skin are exhausted by chronic antigenic stimulation. However, they did not upregulate TOX, a hallmark of T cell exhaustion. Intriguingly, CD44high NKG2D-expressing CD8 T cells appeared in the thymi of aged C3H/HeJ mice before disease induction. These cells express TBET and EOMES without overt expansion of PLZF-expressing T cells. Collectively these features suggest AA is mediated by autoreactive activation CD8 T cells that are not explained by previously known mechanisms. This research was supported by the National Research Foundation of Korea (NRF-2022R1A2C1007692)

PURPOSE Total neoadjuvant therapy (TNT) is a newly established standard treatment for rectal adenocarcinoma. Current methods to communicate magnitudes of regression during TNT are subjective and imprecise. Magnetic resonance tumor regression grade (MR-TRG) is an existing, but rarely used, regression grading system. Prospective validation of MR-TRG correlation with pathologic response in patients undergoing TNT is lacking. Utility of adding diffusion-weighted imaging to MR-TRG is also unknown. METHODS We conducted a multi-institutional prospective imaging substudy within NRG-GI002 (ClinicalTrials.gov identifier: NCT02921256 ) examining the ability of MR-based imaging to predict pathologic complete response (pCR) and correlate MR-TRG with the pathologic neoadjuvant response score (NAR). Serial MRIs were needed from 110 patients. Three radiologists independently, then collectively, reviewed each MRI for complete response (mriCR), which was tested for positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity with pCR. MR-TRG was examined for association with the pathologic NAR score. All team members were blinded to pathologic data. RESULTS A total of 121 patients from 71 institutions met criteria: 28% were female (n = 34), 84% White (n = 101), and median age was 55 (24-78 years). Kappa scores for T- and N-stage after TNT were 0.38 and 0.88, reflecting fair agreement and near-perfect agreement, respectively. Calling an mriCR resulted in a kappa score of 0.82 after chemotherapy and 0.56 after TNT reflected near-perfect agreement and moderate agreement, respectively. MR-TRG scores were associated with pCR ( P < .01) and NAR ( P < .0001), PPV for pCR was 40% (95% CI, 26 to 53), and NPV was 84% (95% CI, 75 to 94). CONCLUSION MRI alone is a poor tool to distinguish pCR in rectal adenocarcinoma undergoing TNT. However, the MR-TRG score presents a now validated method, correlated with pathologic NAR, which can objectively measure regression magnitude during TNT.