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Synapse loss is an early and invariant feature of Alzheimer's disease (AD) and there is a strong correlation between the extent of synapse loss and the severity of dementia. Accordingly, it has been proposed that synapse loss underlies the memory impairment evident in the early phase of AD and that since plasticity is important for neuronal viability, persistent disruption of plasticity may account for the frank cell loss typical of later phases of the disease. Extensive multi-disciplinary research has implicated the amyloid β-protein (Aβ) in the aetiology of AD and here we review the evidence that non-fibrillar soluble forms of Aβ are mediators of synaptic compromise. We also discuss the possible mechanisms of Aβ synaptotoxicity and potential targets for therapeutic intervention.

Background Genomic studies of high-grade/progressive meningiomas have reported a heterogeneous mutation spectrum, identifying few recurrently mutated genes. Most studies have been underpowered to detect genomic subclasses of aggressive meningiomas due to relatively small number of available samples. Here, we present a genomic survey of one of the largest multi-institutional cohorts of high-grade/progressive meningiomas to date. Methods 850 high-grade/progressive meningiomas, including 441 WHO grade 2 and 176 WHO grade 3 meningiomas and 220 progressive WHO grade 1 meningiomas, were tested as part of a clinical testing program by hybridization capture of 406 cancer-related genes to detect base substitutions, indels, amplifications, deletions, and rearrangements. Information from pathology reports, histopathology review, and patient clinical data was assessed. Results Genomic analyses converged to identify at least three distinct patterns of biologically-aggressive meningiomas. The first and most common contained NF2 -mutant tumors (n = 426, 50%), was associated with male sex (64.4% %, p  = 0.0001) and often harbored additional mutations in CDKN2A / B (24%), and the chromatin regulators ARID1A (9%), and KDM6A (6%). A second group ( NF2 -agnostic) featured TERT promoter ( TERT p; n = 56) or TP53 mutations (n = 25) and were either NF2 -mutant or wild-type, and displayed no association with either sex ( p  = 0.39). The remaining group generally lacked NF2 mutations, and accounted for 40% of the cases—with three subgroups. One consistent primarily of grade 3 lesions harboring alterations in chromatin regulators BAP1 (n = 22) or PBRM1 (n = 16). A second subgroup contained AKT1 (n = 26), PIK3CA (n = 14) and SMO (n = 7) mutant skull-based meningiomas, and a third mixed subgroup included 237 meningiomas with a heterogeneous spectrum of low frequency and non-recurrent alterations. Conclusions Our findings indicate that the patterns of genomic alterations in high-grade/progressive meningiomas commonly group into three different categories. The most common NF2 -associated canonical group frequently harbored CDKN2A / B alterations, which is potentially amenable to targeted therapies. An NF2 -agnostic group harbored frequent TERT p and TP53 mutations. The final subclass, distinct from the canonical NF2 mutant associated pathway, was partly characterized by BAP1 / PBRM1 alterations (rhabdoid/papillary histology) or skull-base disease. Overall, these data increase our understanding of the pathobiology of high-grade/progressive meningiomas and can guide the design of clinical trials. IRB approval status Reviewed and approved by Western IRB; Protocol No. 20152817.

Dynamic tracking of spinal instrumentation could facilitate real-time evaluation of hardware integrity and in so doing alert patients/clinicians of potential failure(s). Critically, no method yet exists to continually monitor the integrity of spinal hardware and by proxy the process of spinal arthrodesis; as such hardware failures are often not appreciated until clinical symptoms manifest. Accordingly, herein, we report on the development and engineering of a bio-adhesive metal detector array (BioMDA), a potential wearable solution for real-time, non-invasive positional analyses of osseous implants within the spine. The electromagnetic coupling mechanism and intimate interfacial adhesion enable the precise sensing of the metallic implants position without the use of radiation. The customized decoupling models developed facilitate the precise determination of the horizontal and vertical positions of the implants with incredible levels of accuracy (e.g., <0.5 mm). These data support the potential use of BioMDA in real-time/dynamic postoperative monitoring of spinal implants. No method exists for real-time evaluation of the status of spinal implants. Here, the authors developed a bio-adhesive metal detector array (BioMDA) that provides a wearable, non-invasive solution for positional analyses of osseous implants within the spine.

Aggressive neurosurgical resection to achieve sustained local control is essential for prolonging survival in patients with lower-grade glioma. However, progression in many of these patients is characterized by local regrowth. Most lower-grade gliomas harbor isocitrate dehydrogenase 1 (IDH1) or IDH2 mutations, which sensitize to metabolism-altering agents. To improve local control of IDH mutant gliomas while avoiding systemic toxicity associated with metabolic therapies, we developed a precision intraoperative treatment that couples a rapid multiplexed genotyping tool with a sustained release microparticle (MP) drug delivery system containing an IDH-directed nicotinamide phosphoribosyltransferase (NAMPT) inhibitor (GMX-1778). We validated our genetic diagnostic tool on clinically annotated tumor specimens. GMX-1778 MPs showed mutant IDH genotype-specific toxicity in vitro and in vivo, inducing regression of orthotopic IDH mutant glioma murine models. Our strategy enables immediate intraoperative genotyping and local application of a genotype-specific treatment in surgical scenarios where local tumor control is paramount and systemic toxicity is therapeutically limiting.

Background CD19-directed chimeric antigen receptor T-cell therapy (CD19-CAR) has yielded encouraging efficacy in CNS lymphomas (CNSL), but most patients ultimately experience progressive disease (PD). Risk factors, progression patterns as well as optimal salvage therapies remain unclear. Methods Clinical and radiological characteristics of CD19-CAR failure were therefore retrospectively defined in CNSL treated at Massachusetts General Hospital from 2018 to 2024. PD patterns were defined as local or distant. CNS-progression-free survival from CD19-CAR infusion (CNS-PFS1) and first subsequent progression (CNS-PFS2) were analyzed. Results CD19-CAR achieved a 60% overall response rate (45% complete (CR), 15% partial response) in 60 recurrent CNSL. Median CNS-PFS1 was 4 months with radiographic PD in 36 patients (local 23.3%; local and distant 16.7%; distant 20%). PD patterns were associated with prior CD19-CAR response: Distant relapse typically occurred after CR whereas local PD followed CD19-CAR refractory disease. Peripherally contrast enhancing CNSL (pCE) at CD19-CAR infusion correlated with refractory disease. Leptomeningeal involvement (LMD) was associated with recurrence after CR. On multivariable Cox regression, pCE (Hazard ratio [HR]: 2.75; 95%-Confidence interval [CI]: 1.08–6.68, p  = 0.03) and LMD (HR: 2.72; CI: 1.20–6.25, p  = 0.02) were independently associated with shorter CNS-PFS1. At progression, peripheral CD19 + -B-cell aplasia suggested CD19-CAR persistence in 93% of patients. Median CNS-PFS2 after CD19-CAR failure was one month. Salvage immune checkpoint inhibition, and lenalidomide with rituximab/tafasitamab yielded prolonged responses. Conclusions This study identifies novel radiological risk factors for CD19-CAR failure in CNSL, namely pCE and LMD. Outcome in this setting is unfavorable and encouraging salvage treatments warrant prospective evaluation.

Hemangioblastomas consist of 10-20% neoplastic “stromal” cells within a vascular tumor cell mass of reactive pericytes, endothelium and lymphocytes. Familial cases of central nervous system hemangioblastoma uniformly result from mutations in the Von Hippel-Lindau ( VHL ) gene. In contrast, inactivation of VHL has been previously observed in only a minority of sporadic hemangioblastomas, suggesting an alternative genetic etiology. We performed deep-coverage DNA sequencing on 32 sporadic hemangioblastomas (whole exome discovery cohort n = 10, validation n = 22), followed by analysis of clonality, copy number alteration, and somatic mutation. We identified somatic mutation, loss of heterozygosity and/or deletion of VHL in 8 of 10 discovery cohort tumors. VHL inactivating events were ultimately detected in 78% (25/32) of cases. No other gene was significantly mutated. Overall, deep-coverage sequence analysis techniques uncovered VHL alterations within the neoplastic fraction of these tumors at higher frequencies than previously reported. Our findings support the central role of VHL inactivation in the molecular pathogenesis of both familial and sporadic hemangioblastomas.

The synaptotoxic Aβ protein aggregates in the brains of individuals with Alzheimer's disease. Dennis Selkoe and his colleagues identify the size of the Aβ aggregate in the brains of individuals with Alzheimer's disease that is responsible for the deficits of learning and memory that characterize the disease. Alzheimer's disease constitutes a rising threat to public health. Despite extensive research in cellular and animal models, identifying the pathogenic agent present in the human brain and showing that it confers key features of Alzheimer's disease has not been achieved. We extracted soluble amyloid-β protein (Aβ) oligomers directly from the cerebral cortex of subjects with Alzheimer's disease. The oligomers potently inhibited long-term potentiation (LTP), enhanced long-term depression (LTD) and reduced dendritic spine density in normal rodent hippocampus. Soluble Aβ from Alzheimer's disease brain also disrupted the memory of a learned behavior in normal rats. These various effects were specifically attributable to Aβ dimers. Mechanistically, metabotropic glutamate receptors were required for the LTD enhancement, and N -methyl D -aspartate receptors were required for the spine loss. Co-administering antibodies to the Aβ N-terminus prevented the LTP and LTD deficits, whereas antibodies to the midregion or C-terminus were less effective. Insoluble amyloid plaque cores from Alzheimer's disease cortex did not impair LTP unless they were first solubilized to release Aβ dimers, suggesting that plaque cores are largely inactive but sequester Aβ dimers that are synaptotoxic. We conclude that soluble Aβ oligomers extracted from Alzheimer's disease brains potently impair synapse structure and function and that dimers are the smallest synaptotoxic species.