Scholarly Activity

BACKGROUND: Small extracellular vesicles (sEVs) mediate intercellular communication in the central nervous system, regulating processes ranging from homeostatic maintenance to injury repair. Although astrocytes are a major source of sEVs in the brain, in vivo investigation of their endogenous and cell-specific signaling remains technically challenging.

NEW METHOD: To address this limitation, we developed a novel inducible transgenic reporter mouse line, GFAP-CD63-GFP, that enables specific labeling of astrocyte-derived sEVs. The mouse line was generated by crossing GFAP-CreERT2 mice with CD63-emGFPloxP/stop/loxP mice. This system enables Tamoxifen-inducible, astrocyte-specific expression of GFP-tagged CD63, a tetraspanin enriched in sEVs. The model allows visualization and quantification of astrocyte-derived CD63-positive sEVs in vivo.

RESULTS: Following Tamoxifen induction, GFP expression was robustly detected in the brain and spinal cord. Immunogold transmission electron microscopy further identified GFP-positive sEVs within neurons, providing ultrastructural evidence of astrocyte-to-neuron vesicle transfer. As a proof-of-concept, ischemic stroke significantly increased astrocyte-derived sEVs in the ipsilesional cerebral hemisphere and the stroke-impaired side of the spinal cord, accompanied by enhanced neuronal endocytosis.

COMPARISON WITH EXISTING METHODS: Current approaches rely primarily on in vitro EV isolation or nonspecific membrane dyes. The GFAP-CD63-GFP model enables cell type-specific, temporally controlled, and in situ tracking of astrocyte-derived sEVs.

CONCLUSIONS: These findings provide the first in vivo demonstration of increased astrocyte-to-neuron sEV communication during post-stroke recovery. The GFAP-CD63-GFP reporter mouse thus provides a powerful platform for investigating astrocyte-derived sEV signaling under both physiological and pathophysiological conditions of the CNS.

Muscle injury resulting in markedly elevated creatine kinase levels is termed rhabdomyolysis. The muscle damage can occur because of direct or indirect trauma, or it can be related to the use of certain medications, toxins, illicit drugs, or the presence of underlying inflammatory, metabolic, or genetic disorders with a predisposition for rhabdomyolysis. A detailed review of history can help in identifying the underlying etiology. Identification and removal of the triggering/inciting factor and noxious stimuli should be attempted as soon as possible. Careful evaluation for any complications and initiation of appropriate treatment are recommended. Aggressive fluid therapy, correction of metabolic derangement, and, when warranted, renal replacement therapy, form the mainstays of treatment.

This systematic review (PROSPERO CRD420246206360) investigated relationships between self-reported or objective sleep duration and fluid biomarkers of Alzheimer's disease pathology and neurodegeneration: cerebrospinal fluid or blood Aβ, p-tau181, t-tau, NfL and GFAP. We searched PubMed, SCOPUS, and CINAHL from inception to September 2024. Twenty studies (n = 12,445) met inclusion criteria (13 cerebrospinal fluid biomarkers [n = 2836]; 7 blood biomarkers [n = 9609]). Study quality was assessed using Newcastle-Ottawa scales. Whereas many studies did not report any associations, some trends emerged: short sleep duration was associated with higher cerebrospinal fluid t-tau and p-tau181 and lower cerebrospinal fluid or blood Aβ42 across multiple studies. Longer sleep duration showed more variable associations, with some suggesting either worse or better biomarker profiles (e.g., higher and lower fluid t-tau, p-tau181, or Aβ42). Two studies investigating non-linear relationships identified U-shaped associations, suggesting both short (≤5-6 h) and long (≥8 h) sleep durations are associated with altered biomarker profiles. The predominantly cross-sectional and high heterogeneity of the available evidence, as well as the relatively small number of studies by individual biomarker (especially for NfL and GFAP) limit conclusions about sleep-biomarker relationships. Future research should investigate emerging blood-based biomarkers and explore temporal associations between sleep duration and Alzheimer's disease biomarker changes.

This systematic review (PROSPERO CRD420246206360) investigated relationships between self-reported or objective sleep duration and fluid biomarkers of Alzheimer's disease pathology and neurodegeneration: cerebrospinal fluid or blood Aβ, p-tau181, t-tau, NfL and GFAP. We searched PubMed, SCOPUS, and CINAHL from inception to September 2024. Twenty studies (n = 12,445) met inclusion criteria (13 cerebrospinal fluid biomarkers [n = 2836]; 7 blood biomarkers [n = 9609]). Study quality was assessed using Newcastle-Ottawa scales. Whereas many studies did not report any associations, some trends emerged: short sleep duration was associated with higher cerebrospinal fluid t-tau and p-tau181 and lower cerebrospinal fluid or blood Aβ42 across multiple studies. Longer sleep duration showed more variable associations, with some suggesting either worse or better biomarker profiles (e.g., higher and lower fluid t-tau, p-tau181, or Aβ42). Two studies investigating non-linear relationships identified U-shaped associations, suggesting both short (≤5-6 h) and long (≥8 h) sleep durations are associated with altered biomarker profiles. The predominantly cross-sectional and high heterogeneity of the available evidence, as well as the relatively small number of studies by individual biomarker (especially for NfL and GFAP) limit conclusions about sleep-biomarker relationships. Future research should investigate emerging blood-based biomarkers and explore temporal associations between sleep duration and Alzheimer's disease biomarker changes.

OBJECTIVES: To critically evaluate the current International Classification of Headache Disorders, 3rd edition (ICHD-3) definition of status migrainosus (SM) and assess how well it meets clinical and research needs. The review will also explore additional attack dimensions that could support a more patient-centric and clinically actionable definition.

BACKGROUND: ICHD-3 defines SM as a debilitating migraine attack lasting more than 72 h. This 72-h threshold is historically derived rather than empirically validated, and limited evidence is available to guide treatment. We posit that a primarily duration-based definition restricts both the clinical utility of SM and its usefulness as a construct in acute treatment trials.

METHODS: This narrative review was structured around five key questions: (Q1) Do we need specific diagnostic criteria for SM; (Q2) Should time be used within the definition; (Q3) Should attack severity and disability be included; (Q4) Should treatment response be included; and (Q5) Should migraine attack phases be considered. Targeted PubMed searches (inception-mid-2025) were performed for questions 2-5. One reviewer was assigned to each of these questions and independently conducted title/abstract screening, full-text review, and data extraction.

RESULTS: Searches yielded 36 publications from 504 screened for question 2, 12 from 322 for question 3, 61 from 171 for question 4, and 13 from 1708 for question 5. Q1: Although SM remains clinically useful, the current criteria do not capture the heterogeneity of prolonged attacks and provide limited guidance for treatment escalation. Q2: Attack duration varies widely across migraine phenotypes, and the 72-h cutoff lacks clear justification and is misaligned with real-world practice, where escalation occurs well before 72 h. Q3: "Debilitating" is undefined, and pain severity alone insufficiently reflects functional impact; disability may offer a more meaningful indicator for clinical decision-making. Q4: Treatment refractoriness is central to how prolonged attacks are managed but is not incorporated into current criteria, and standardized definitions of acute treatment failure are lacking. Q5: Prodrome, aura, and postdrome can meaningfully contribute to attack burden, yet SM criteria do not specify whether nonheadache phases count toward attack duration.

CONCLUSIONS: A revised definition of SM should move beyond a rigid 72-h threshold and give greater weight to functional impairment, treatment response, and more explicit definitions of attack duration that clarify how nonheadache phases are handled.

The eye is highly susceptible to inflammation-induced tissue damage; however, the mechanisms that drive inflammation resolution during ocular infections remain unclear. In this study, we utilize a murine model of intraocular bacterial infection (S. aureus-induced endophthalmitis) and lipidomics analysis to uncover a critical role of pro-resolving lipid mediators, particularly resolvin D1 (RvD1), in resolving inflammation and restoring ocular tissue homeostasis and vision. RvD1 protects mouse eyes from severe endophthalmitis by enhancing bacterial clearance, suppressing intraocular inflammation, and preserving retinal structure and function. Pharmacological inhibition of formyl peptide receptor 2 (FPR2) reveals that RvD1's protective effects mainly rely on FPR2 signaling. Unexpectedly, RvD1 is unable to resolve inflammation or protect the eye in the absence of Toll-like receptor 2 (TLR2), a critical pattern recognition receptor in ocular S. aureus infections. These findings reveal an unrecognized interplay between TLR2 and FPR2 signaling, including their mutual regulation and physical receptor interactions during bacterial infection. Overall, these findings provide new insights into the coordinated roles of TLR2 and FPR2 in resolving inflammation and protecting the eye during bacterial infections.

OBJECTIVES: Temporal lobe epilepsy (TLE) impacts multiple brain networks. Aberrant functional connectivity has been demonstrated in resting-state networks (RSNs) that mediate higher brain functions in TLE. This study aimed to identify the reproducible patterns of altered functional connectivity in TLE in a large, international cohort through ENIGMA-Epilepsy.

METHODS: Resting-state functional MRI datasets from nine centers across North America, South America, Europe and South Africa, including 442 people with TLE and 387 healthy adults, were analyzed. We examined group differences in whole-brain connectivity in patients compared to controls in seven major RSNs. We also investigated whole-brain connectivity maps for key nodes within the default mode network (DMN). Furthermore, the associations between connectivity patterns and clinical variables were assessed.

RESULTS: We found lower within-network connectivity scores (13.6% on average) and higher between-network connectivity scores (129% on average) in non-limbic RSN in TLE. This pattern was reproducible across all seven sites and most robust for DMN and visual networks. Patterns of connectivity were not associated with age of seizure onset or disease duration and were mostly similar in patients with left and right TLE with a few exceptions; isolated regions of high connectivity in left TLE and lower connectivity in right TLE compared to controls.

SIGNIFICANCE: We show strong evidence of lower connectivity within most RSNs and higher connectivity outside of these networks that was highly consistent across geographically diverse sites, demonstrating the robustness and generalizability of our findings. The findings demonstrate a consistent disruption of network organization in TLE that may underlie cognitive co-morbidities and seizure propagation patterns observed in this patient population.

PLAIN LANGUAGE SUMMARY: In this international ENIGMA-Epilepsy study, resting-state fMRI data from 442 individuals with TLE showed reduced connectivity within major resting-state networks (about 14% lower) and markedly increased connectivity between networks (about 129% higher), compared to 387 healthy controls. These patterns were highly reproducible across sites. Connectivity alterations were not related to age of onset or disease duration and were largely similar across left and right TLE, aside from small, region-specific differences. Overall, the study demonstrates a robust, widespread reorganization of brain network connectivity in TLE, which may help explain associated cognitive difficulties and seizure spread.

BACKGROUND: Drug-resistant epilepsy (DRE) remains a debilitating condition for those affected. This meta-analysis evaluates the effectiveness of Deep Brain Stimulation (DBS) as a neuromodulatory treatment option in improving seizure control and quality of life (QOL) in epilepsy.

METHODS: PubMed, EMBASE (Elsevier), CiNAHL, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Scopus, and Web of Science were searched for articles from their inception to August 2024 by two independent reviewers using the Preferred Reporting items for Systematic Reviews and Meta-analysis (PRISMA) system. The review was registered prospectively with PROSPERO (CRD42023463358).

RESULTS: From 756 screened studies, 25 met eligibility criteria, comprising 480 patients with DRE undergoing DBS. Short-term follow-up showed that 41.6% achieved ≥50% seizure reduction at 3-6 months, increasing to 63% at ≥1 year. The pooled SUDEP proportion was 1%. Pooled mean QOLIE-31 scores were 47.59 at baseline, 56.11 at 3 months, 58.55 at 6 months, and 50.11 at ≥1 year, representing time-specific estimates derived from different study samples. The mean improvements at 3 and 6 months (+8.52 and +10.96) exceeded the minimal clinically important difference of 5 points.

CONCLUSION: DBS reduces seizure burden and yields early improvements in QOL among patients with DRE, with pooled QOLIE-31 estimates suggesting clinically meaningful gains in the early postoperative period. However, later timepoint estimates were more variable and should be interpreted cautiously, as they do not represent longitudinal trajectories within the same patients. These findings support DBS as an effective therapeutic option and highlight the need for future studies to optimize patient selection and long-term outcomes.

Background: Unfractionated heparin (UFH) remains the standard anticoagulant for extracorporeal membrane oxygenation (ECMO), despite complications, such as heparin resistance, heparin-induced thrombocytopenia, bleeding and variable pharmacokinetics. This has prompted the search for alternative and novel anticoagulation strategies, including pharmacologic agents, circuit modifications, and monitoring approaches. This scoping review aimed to map the breadth and characteristics of evidence on ECMO anticoagulation strategies beyond UFH.

Methods: A comprehensive search of peer-reviewed and gray literature was conducted across PubMed, Cochrane, Clinical Trials, WHO Trials Registry, and conference abstracts through manual searches in key journals. Clinical, pre-clinical, and gray literature studies evaluating pharmacologic agents, anticoagulation-free or heparin-sparing, biocompatible circuits, and monitoring innovations were included. Data were charted and synthesized descriptively to identify trends, gaps, and emerging directions.

Results: A total of 269 records were included. Evidence was highly heterogeneous among study designs, populations, ECMO modalities, and outcome definitions. Most clinical studies were retrospective cohorts and adult-centered, with limited multicenter randomized controlled trials and underrepresentation of neonatal and pediatric populations. Direct thrombin inhibitors were frequently studied and clinically implemented alternatives to UFH. Other agents, including nafamostat mesylate, prostaglandin E1, and factor pathway inhibitors remain early in clinical investigation. Anticoagulation-free strategies and biocompatible circuit technologies were mostly supported through pre-clinical and single-center studies. Monitoring and modeling innovations, like TEG, ROTEM, real-time imaging, and machine learning, are quickly emerging.

Conclusions: ECMO anticoagulation is transitioning from UFH reliance toward diversified and personalized strategies. Future research should prioritize multicenter randomized controlled trials, standardize protocols, expand to neonatal and pediatric investigation, and integrate strategies.

OBJECTIVES: Traumatic brain injury (TBI) is a major cause of mortality and long-term neurological disabilities. Adenosine monophosphate-activated protein kinase (AMPK), a key cellular energy sensor, plays a critical role in maintaining energy homeostasis. Loss of AMPK phosphorylation following TBI impairs the restoration of cellular energy homeostasis and promotes inflammation. In this study, we investigated whether post-TBI loss of AMPK worsens functional impairments, amplifies inflammation, and exacerbates tissue damage in a mouse model of TBI.

METHODS: Adult male C57BL/6 wild-type (WT) and (AMPKα1-KO) mice were subjected to TBI or sham surgery. Behavioral assessments were performed at 24 h post-TBI, followed by mice were anesthetized, and their brains were rapidly collected for histological and biochemical analyses. To further support our findings, mixed glial cells isolated from WT and AMPKα1-KO pups were treated with lipopolysaccharides and interferon-gamma (LI) (0.1 μg/ml LPS and 20 ng/ml IFNg) for 6 h to induce an inflammatory response.

RESULTS: Our results show that TBI reduces AMPK phosphorylation in WT mice and that AMPK loss correlates with worsened behavioral deficits, enhanced NLRP3 inflammasome activation, and elevated levels of pro-inflammatory mediators, including IL-1β. Similarly, AMPKα1-KO glial cells exhibited greater activation of NLRP3 inflammasome and higher expression of pro-inflammatory markers, such as IL-1β, IL-6, TNF-α, iNOS, and Cox 2, compared with WT cells.

CONCLUSIONS: Collectively, our results demonstrate that AMPKα1 is a critical endogenous regulator of glial-driven neuroinflammation and secondary tissue damage following TBI. Restoring AMPKα1 activity after TBI may therefore represent a promising therapeutic strategy to attenuate neuroinflammation and limit TBI-associated neurological damage.