Citations

Abstract INTRODUCTION Tauopathies are a heterogeneous group of neurodegenerative disorders defined by abnormal aggregation of tau protein. Although cryogenic electron microscopy (cryo‐EM) has uncovered disease‐specific tau structures, translating these insights into diagnostic tools remains difficult. METHODS We developed a heparin‐free, salt‐modulated real‐time quaking‐induced conversion (RT‐QuIC) assay using K12 and K11 tau substrates, targeting aggregation‐prone regions. This current method improves on previous methodology by minimising the number of required substrates by modulating reaction salt content in order to differentiate yet‐undistinguished tauopathy strains. Thioflavin T fluorescence kinetics and attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR) spectroscopy were used to classify tau aggregates from human brain homogenates. RESULTS This method differentiated eight tauopathies, including Alzheimer's disease, Pick disease, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), argyrophilic grain disease (AGD), frontotemporal dementia with parkinsonism associated with chromosome 17 with N279K mutation (FTDP‐17 N279K), and globular glial tauopathies types II and III. Subclassification of 4R tauopathies was achieved by modulating salt conditions and analyzing aggregation profiles. FTIR confirmed preservation of conformational differences. DISCUSSION This salt‐modulated, heparin‐free RT‐QuIC platform enables sensitive tauopathy classification based on strain‐specific kinetics and structure. It offers a practical tool for diagnostic development, mechanistic studies, and therapeutic screening.

Abstract INTRODUCTION The locus coeruleus (LC) degenerates early in Alzheimer's disease (AD). However, the extent of rostrocaudal degeneration across clinicopathologic heterogeneity remains underexplored in AD. METHODS Using digital pathology, we quantified LC neuronal density and area at three neuroanatomic levels in a large AD series. RESULTS Analysis of neuropathologic AD subtypes revealed greater middle LC vulnerability in hippocampal sparing AD compared to typical and limbic predominant AD. Regression analyses identified distinct predictor variables associated with the degeneration of rostral and middle LC. Age at onset predicted 24% of the variability in rostral LC neuronal density, whereas Braak stage, brain weight, Lewy body disease, and age at onset accounted for 15% of the variability in middle LC. Analyses of clinical presentations revealed lower rostral LC neuronal density in non‐amnestic compared to amnestic AD cases. DISCUSSION These insights demonstrate greater LC degeneration in atypical clinicopathologic forms of AD, including hippocampal sparing, young‐onset, and non‐amnestic presentations.

BACKGROUND: Cerebrovascular disease is prevalent in older adults and is associated with cognitive impairment. Although the association between brain infarcts and cognition has been widely investigated, the contribution of vascular disease to cognitive impairment has been less studied, particularly in non-White populations. We investigated the epidemiological and clinical characteristics of vascular disease phenotypes and their association with cognitive abilities in a diverse population. METHODS: In a Brazilian population–based clinicopathological study (recruitment between 2004 and 2024), inclusion criteria were age at death ≥18 years and the availability of an informant. Clinical information and cognitive abilities were assessed through informant interviews. Hyaline arteriolosclerosis (HA) was evaluated in 13 brain areas and categorized as absent, mild, moderate, or severe. Moderate/severe HA defined microvascular disease (Micro[+]). Intracranial atherosclerosis in the circle of Willis was similarly classified, with moderate/severe cases defining macrovascular disease (Macro[+]). Four vascular profiles were compared: Micro[+]/Macro[+], Micro[−]/Macro[+], Micro[+]/Macro[−], and Micro[−]/Macro[−]. Linear regression models adjusted for sociodemographic, clinical, and cerebrovascular/neurodegenerative lesions evaluated the association of cognition with vascular profiles, and microvascular and macrovascular diseases separately. RESULTS: Of 2418 participants, 834 with missing data were excluded, yielding a final sample of 1584 individuals (mean age, 74.3±13.4 years; 776 [49%] women; 982 [62%] White). Microvascular disease was slightly more frequent (31%) than macrovascular (29%). Regarding vascular profiles, 788 (50%) participants were Micro[−]/Macro[−], 334 (21%) Micro[+]/Macro[−], 301 (19%) Micro[−]/Macro[+], and 161 (10%) Micro[+]/Macro[+]. Micro[+] participants were older and more frequently women, and had worse cognitive abilities. Vascular groups were similar regarding most clinical comorbidities. HA (β, 0.81 [95% CI, 0.25–1.36]; P =0.004) and Micro[+]/Macro[+] phenotype (β, 1.25 [95% CI, 0.38–2.12]; P =0.005) were associated with worse cognitive abilities compared with HA-negative and Micro[−]/Macro[−] participants, respectively. CONCLUSIONS: HA was as frequent as intracranial atherosclerosis. HA and the vascular phenotype with both microvascular and macrovascular diseases were associated with worse cognition.

BACKGROUND: With pulmonary hypertension (PH), a pulmonary artery wedge pressure (PAWP)>15 mm Hg is used to diagnose left heart dysfunction, but some patients with adjudicated group 1 PH demonstrate PAWP>15 mm Hg. The primary objective of the study was to evaluate group 1 PH with high PAWP>15 mm Hg. METHODS: Patients with adjudicated group 1 PH from PVDOMICS between 2016 and 2019 were separated into high PAWP(>15 mm Hg) or normal PAWP and compared with adjudicated combined pre- and postcapillary (Cpc) PH related to heart failure with preserved ejection fraction (HFpEF). Participants underwent dynamic right heart catheterization and metabolomics. Findings were validated in 3 independent cohorts with adjudicated group 1 PH (validation cohorts 1 and 2 with exercise right heart catheterization and validation cohort 3 with resting right heart catheterization). RESULTS: Of 325 patients with group 1 PH (73% women, mean age 53.0±14.3 years), 15% (n=48) had high PAWP. Group 1 PH+high PAWP demonstrated greater obesity, left ventricular hypertrophy ( P <0.0002), left ventricular strain impairment ( P <0.0001), and decreased left ventricular compliance ( P <0.0001) compared with group 1 PH+normal PAWP, with changes comparable to Cpc-PH HFpEF (n=75). Compared with Cpc-PH HFpEF, left atrial function was better in group 1 PH+high PAWP with lower PAWP V wave, higher left atrial compliance, and left atrial ejection fraction ( P <0.0001 for all). Metabolomics demonstrated little difference between group 1 PH with high versus normal PAWP but large differences between group 1 PH+high PAWP versus Cpc-PH HFpEF (100 metabolites altered at false discovery rate P <0.05). Elevated PAWP was also observed in 18% of group 1 PH in the validation cohort 1 (n=402), with exercise PAWP response intermediately abnormal in group 1 PH+high PAWP relative to Cpc-PH HFpEF and group 1 PH+normal PAWP (interaction P <0.0001). Elevated PAWP was similarly observed in 22% and 19% of group 1 PH in validation cohorts 2 (n=55) and 3 (n=787), respectively. CONCLUSIONS: Approximately 1 in 5 adjudicated patients with group 1 PH has elevation in resting PAWP despite severe pulmonary vascular dysfunction and metabolomics consistent with traditionally defined group 1 PH. Despite resting PAWP elevation, these patients with group 1 PH were metabolomically and biologically distinct from Cpc PH HFpEF, with better left atrial function and diastolic reserve during exercise. These data emphasize the limitations of using resting PAWP alone to separate group 1 PH from HFpEF and call for development of more integrated clinical diagnostic criteria.

A 75-year-old male was admitted with worsening anemia and spontaneous bruising in the left abdominal wall and paraspinal region. Laboratory workup revealed low factor XIII (FXIII) activity levels. Cryoprecipitate transfusions raised his FXIII level, but still fluctuated drastically, ranging from 4 to 43% was discharged 3 days later once his bleeding was managed. Three days later, he was readmitted for severe pain and new bruising in his latissimus dorsi and lateral right thigh. CT-scan revealed hemothorax and arterial bleeding requiring an urgent angiogram with embolization. Chromogenic and functional FXIII assays were unable to elucidate an inhibitor at this time. Management included FXIII concentrate, rituximab, and prednisone; the patient was discharged 12 days later with FXIII levels of 50%. After prednisone tapering, FXIII levels decreased drastically. This case exemplified that higher levels of FXIII are required to prevent bleeding diatheses rather than the previously reported minimum of 5% activity. Despite the diagnostic uncertainty of laboratory testing, the shortened half-life of FXIII activity following replacement therapy and favorable response to immunotherapy indicates that the bleeding diathesis was caused by an acquired inhibitor.

Abstract Recent advances in long-read transcriptome sequencing enable high-throughput profiling of full-length RNA isoforms in bulk, single-cell, and single-nucleus samples. However, long-read datasets typically contain a mixture of complete and partial transcripts, leading to pervasive ambiguity in read-to-isoform assignment and complicating accurate isoform identification and quantification, particularly in the absence of reliable reference annotations. These challenges are further amplified in single-cell and single-nucleus samples, where coverage is sparse and transcriptional heterogeneity is high. Here, we present the Long Read Alignment Assembler (LRAA), a unified and versatile computational framework for isoform identification and quantification from long-read RNA sequencing data across bulk, single-cell, and single-nucleus transcriptomic samples. LRAA combines splice-graph based structural modeling with expectation maximization based optimization to probabilistically resolve ambiguous read assignments and improve isoform abundance estimation. The framework supports quantification-only, reference-guided, and fully reference-free (de novo) modes of analysis within a single methodological paradigm. We benchmarked LRAA using both simulated and genuine long-read datasets spanning sequencing standards and whole transcriptomes. Central to this evaluation is a novel benchmarking strategy based on Multiplexed Overexpression of Regulatory Factors (MORFs), which provides biologically expressed, barcoded isoforms with unambiguous read-level ground truth. Across all benchmarks, including MORFs, synthetic spike-ins, and whole-transcriptome datasets, LRAA consistently outperformed state-of-the-art methods in isoform identification accuracy, sensitivity, and expression quantification. Finally, we demonstrate the biological utility of LRAA by resolving cell-type-specific isoform usage across peripheral blood immune cell populations and by detecting a pathogenic cryptic isoform of STMN2 with associated transcriptional changes in single-nucleus RNA-seq data from frontal cortex tissue of an individual with frontotemporal dementia (FTD). Together, these results establish LRAA as a robust and general solution for resolving transcript diversity in complex biological systems, from development to disease.

Abstract Introduction: Recruitment for rare disease studies is challenging due to small eligible populations. Traditional clinical research management systems often lack tools to track recruitment contacts prior to enrollment. The NET-PRO study, focused on neuroendocrine tumors (NETs), implemented a participation monitoring system to enhance recruitment efficiency and representativeness. Methods: NET-PRO is a multicenter cohort study of 2538 adults diagnosed with gastroenteropancreatic (GEP) or lung NETs between January 2018 and September 2024. Recruitment occurred from January 2022 to February 2025 across 14 U.S. medical centers. Sites used flexible recruitment methods (email, mail, phone, in-clinic) and tracked contacts using REDCap-based tools. Participant characteristics were analyzed by enrollment mode (online or mail) and recruitment difficulty (number of contacts required prior to enrollment) using standardized mean differences, chi-square tests, and ANOVA. Results: Of 9279 contacted patients, 2675 consented (28.8%) and 2538 enrolled (27.4%). Most enrolled online (83.2%), while 16.8% enrolled by mail. Mail respondents were older, had lower education and income, and more comorbidities. Among those enrolled, recruitment difficulty was associated with older age, lower education and income, but not comorbidity. Over half of the most difficult-to-recruit participants enrolled online. Contact methods varied by attempt, with email dominating early contacts and phone/mail used more in later attempts. Conclusions: A participation monitoring tool supported flexible, multimodal recruitment and improved sample representativeness in a rare cancer study. Tracking recruitment contacts enabled adaptive strategies and may reduce bias in observational research by enabling better outreach to harder-to-reach populations.

Abstract Background Colonic strictures in Crohn’s disease (CD) are an important, but understudied clinical problem. Cross-sectional imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), and intestinal ultrasound (IUS) effectively assess the small bowel in CD allowing for the diagnosis of strictures. However, radiologic definitions of colonic strictures and their diagnostic accuracy have not been developed. Endoscopic definitions of colonic strictures are the most well-described. Aims We aimed to systematically review available data to summarize definitions, diagnosis and differentiation between inflammation and fibrosis of colonic strictures on endoscopy, CT, MR, and IUS Methods We conducted a systematic review following PRISMA guidelines using MEDLINE, Scopus, CINAHL, and CENTRAL databases from inception to Oct 6, 2024 to identify literature with diagnostic imaging that included patients with colonic CD strictures. To distinguish fibrosis from inflammation, only studies comparing endoscopy or imaging to a full thickness histologic gold standard were included. Two stage screening was completed in duplicate, and risk of bias was assessed using QUADAS-2 Results 46 studies were eligible for inclusion. Definitions for colonic strictures on CT, MR, and IUS are heterogeneous with combinations of bowel wall thickness, luminal narrowing, and pre-stenotic dilation with no clear cut offs. Endoscopic definitions commonly included lack of colonoscope passage through a narrowed lumen. The diagnostic accuracy of colonic strictures on imaging to detect inflammation and fibrosis against a gold standard of endoscopy or surgical resection is unclear as direct comparisons are few. Meta-analyses were not conducted due to methodological heterogeneity of grading fibrosis and statistical heterogeneity of sensitivity, specificity, and accuracy of colonic stricture diagnoses limited by pooling with small bowel strictures in the studies Conclusions This systematic review describes a lack of definitions for the diagnosis of CD colonic strictures particularly on diagnostic imaging, and the limitations with the current available data to differentiate inflammation from fibrosis. Although bowel wall thickening, luminal narrowing, and pre-stenotic dilation are recognized as hallmark features of small bowel strictures, their adaptation to the colon requires further assessment. Definitions for colonic strictures should likely include imaging combined with endoscopy. Future endeavors are required to develop a consensus to define and diagnose colonic strictures on these modalities Funding Agencies None