Citations

BACKGROUND: With evolving therapy for heart failure with reduced ejection fraction, the benefits of adding a defibrillator in patients undergoing cardiac resynchronization therapy (CRT) remain unclear, particularly for nonischemic cardiomyopathy (NICM). This study evaluates long-term survival among patients with NICM treated with CRT defibrillator (CRT-D) versus CRT pacemaker (CRT-P). METHODS: DECIDE-CRT (Cardiac Resynchronization With or Without Defibrillator in Non-Ischemic Cardiomyopathy) is a multicenter cohort study across 170 US Veterans Affairs hospitals. We identified patients with NICM receiving primary-prevention CRT-P or CRT-D between January 1, 2006, and December 31, 2020. Using a propensity score approach, we applied inverse probability of treatment weighting to balance baseline characteristics between the CRT-P and CRT-D groups. An inverse probability of treatment weighting–weighted Cox model estimated hazards for all-cause mortality. Secondary outcomes included generator replacement, device-related infections, hospitalization for heart failure, and ventricular arrhythmias. RESULTS: Of 16 609 CRT recipients, 3965 met NICM primary-prevention criteria (CRT-D=3158; CRT- P =807). At baseline, patients with NICM receiving CRT-P were much older, with more cardiovascular and noncardiovascular comorbidities compared with the CRT-D group. During the median follow-up of 5.2 years, the mortality rate for CRT-P versus CRT-D was 9.46 versus 9.21 per 100 person-years (RR, 0.97 [95% CI, 0.71–1.13]; P =0.66). The adjusted hazard ratio for all-cause mortality using the inverse probability of treatment weighting-Cox model was 0.90 (95% CI, 0.71–1.13; P =0.34). There was no difference in adjusted hazard for heart failure hospitalization (hazard ratio, 1.27 [95% CI, 0.86–1.87]), while the CRT-D group had higher rates of generator replacement and device-related infections. CONCLUSIONS: This nationwide observational study from the Veterans Affairs Health system did not demonstrate a clear survival advantage with the addition of a defibrillator among patients with NICM receiving CRT although residual confounding cannot be excluded. Given the uncertainty surrounding the incremental benefit of the defibrillator in this setting, a randomized trial is needed to test the incremental value of CRT-D over CRT-P in NICM.

Importance In a phase 2 randomized clinical trial, high-dose vitamin D 3 added to standard treatment improved progression-free survival (PFS) compared with standard-dose vitamin D 3 in patients with metastatic colorectal cancer (mCRC). Objective To determine if high-dose vitamin D 3 added to standard chemotherapy improves outcomes in patients with previously untreated mCRC. Design, Setting, and Participants Double-blind phase 3 randomized clinical trial enrolling 455 patients with previously untreated mCRC, conducted in the US through the National Clinical Trials Network from October 2019 to December 2022 (database freeze: July 15, 2024). Interventions mFOLFOX6 (modified FOLFOX6 [5-fluorouracil, leucovorin, oxaliplatin]) or FOLFIRI (5-fluorouracil, leucovorin, irinotecan) plus bevacizumab every 2 weeks with either high-dose vitamin D 3 (8000 IU daily × 14 days as loading dose followed by 4000 IU daily) or standard-dose vitamin D 3 (400 IU daily) until disease progression, intolerable toxicity, or withdrawal of consent. Main Outcomes and Measures The primary end point was PFS assessed by the unstratified log-rank test. Secondary end points included objective response rate, overall survival, and toxicity. Prespecified subgroup analyses of PFS were performed according to known prognostic factors. Results Among 455 randomized patients (median age, 59 years; 181 [40%] female) with median follow-up 20 months, the median PFS for high-dose vitamin D 3 (n = 228) was 11.8 months (95% CI, 10.3-13.3) vs 10.3 months (95% CI, 9.4-12.2) for standard-dose vitamin D 3 (n = 227) (1-sided log-rank P = .25). There were no significant differences in objective response rate between high-dose and standard-dose vitamin D 3 (51% [95% CI, 44%-58%] vs 44% [95% CI, 37%-50%], respectively; P = .12), or in overall survival (median, 25.6 vs 27.0 months; 1-sided log-rank P = .66). There were no clinically meaningful differences in the most common grade 3 or greater adverse events between the high- and standard-dose groups, including neutropenia (n = 67 [32%] vs n = 62 [30%]) and hypertension (n = 42 [20%] vs n = 49 [23%]) or in incidence of vitamin D–associated toxicities. Conclusions and Relevance Among patients with previously untreated mCRC, addition of high-dose vitamin D 3 , vs standard-dose vitamin D 3 , to standard chemotherapy plus bevacizumab did not improve PFS. Trial Registration ClinicalTrials.gov Identifier: NCT04094688

Urinary urea is a key biomarker for tracking protein oxidation and nitrogen balance. A persistent analytical limitation is that conventional total-nitrogen assays do not deconvolute urinary urea from urinary ammonia, and direct measurement still requires capital-intensive clinical analyzers. Here, we implement and independently validate two cost-effective methods that resolve urinary urea by pairing the presence and absence of urease: Method 1 is a urease-coupled potentiometric assay using an ammonium ion-selective electrode (ISE method); Method 2 is a microplate Berthelot–salicylate colorimetric assay employing a repurposed consumer-grade aquarium ammonia test kit (API®) (API method). Each method was validated against the Roche Cobas C311 clinical analyzer (ISE for urinary ammonia and API for urinary urea) in healthy adult volunteers (n = 10 each), and API–ISE were then compared head-to-head for urinary urea. ISE vs. Cobas yielded R2 = 0.967, slope 95% CI [0.867, 1.173], and Bland–Altman bias of −1.02 mM (95% LoA [−7.40, +5.36] mM). API vs. Cobas yielded R2 = 0.973, slope 95% CI [0.790, 1.039], and bias of −1.55 mM (95% LoA [−11.56, +8.46] mM). API–ISE urinary urea comparison confirmed mutual agreement (R2 = 0.9976, slope 95% CI [0.946, 1.024]; bias of +3.47 mM; 95% LoA [−14.60, +21.53] mM), with mean recoveries near 100% (API: 100.7 ± 2.9%; ISE: 100.6 ± 5.4%; 20–350 mM). Both methods agreed with the clinical analyzer, supporting their potential for decentralized, resource-limited testing; clinical and point-of-care validations are needed.

Iron is an essential element for cellular homeostasis and functionality. Increased iron in the lung is associated with aging and asthma in the elderly (AIE). Using human airway smooth muscle cells from young versus elderly versus AIE patients, we found that dysregulated iron metabolism (more than iron accumulation), resulting in activation of antioxidant systems and increased susceptibility to ferroptosis, occurs in AIE, contributing to cell hyperplasia and matrix remodeling of aging and AIE.

Importance Elevated low-density lipoprotein cholesterol (LDL-C) is a modifiable risk factor for cardiovascular disease, the leading cause of premature death worldwide. Assessing the LDL-C–related burden is critical for guiding prevention and treatment strategies. Objectives To estimate the global, regional, and national burden of ischemic heart disease and ischemic stroke attributable to elevated LDL-C (relative to 35-54 mg/dL) from 1990 to 2023 and to quantify the contributions of population growth, aging, risk-deleted burden, and exposure changes to burden trends. Design, Setting, and Population This comparative risk assessment, part of the Global Burden of Disease Study 2023, estimated population-level LDL-C exposure and associated health loss in 204 countries and territories. Mean LDL-C levels were estimated using spatiotemporal gaussian process regression based on 806 studies across 161 countries. Relative risks were derived from meta-analyses of 38 randomized clinical trials. Population-attributable fractions for deaths and disability-adjusted life-years (DALYs) were estimated by age and sex for adults aged 25 years or older from 1990 to 2023, with 95% uncertainty intervals. Exposure Population-level LDL-C concentrations. Main Outcomes and Measures Population-attributable fractions, counts, and rates (all ages and age standardized per 100 000) of LDL-C–attributable deaths and DALYs from ischemic heart disease and ischemic stroke, with uncertainty intervals. Results In 2023, elevated LDL-C accounted for 3.6 million deaths (95% uncertainty interval, 2.2-5.4 million; 6.0% of global mortality) and 90.7 million DALYs (95% uncertainty interval, 58.9-123.3 million; 3.2% of DALYs). Although global all-ages rates remained stable, age-standardized death and DALY rates decreased by 45.6% and 39.5%, respectively, since 1990. In 2023, age-standardized LDL-C–attributable DALY rates were highest in Eastern Europe and lowest in high-income Asia-Pacific. One-third of the global LDL-C burden occurred in India and China. Population growth and aging drove the increasing burden, with notable regional disparities in LDL-C exposure and risk-deleted DALY rates shifting toward middle-sociodemographic settings. Conclusions and Relevance Despite declining age-standardized rates, the absolute LDL-C burden has increased since 1990 due to demographic changes and has shifted toward middle-sociodemographic countries. Measurement and surveillance gaps persist. Strengthened prevention, diagnosis, and treatment access strategies are essential to mitigate the health burden of LDL-C.

Abstract Introduction Peripheral nervous system innervation of various organs has been associated with the development and maintenance of the immune system. Yet, the intricate details of thymic innervation remain less well-studied. Interestingly, various neurological insults including brain tumors, and neurotropic infections have been shown to have profound impacts on thymic size and cellularity and T cell development. Methods We used flow cytometry, confocal microscopy, neuro tracers, and genetic knockout mice to evaluate developing T cell-neuron interactions within the thymus. Results We have identified neuronal cell bodies within the thymus. These cells express neuronal markers such as NeuN and tyrosine hydroxylase and lack TEC identifiers, such as EpCAM, UEA-1, and Ly51. Thymic neurons can be infected with a neurotropic rabies vector, further cementing their neuronal identity. Considering the thymus consists mostly of T cells, we next investigated a potential interaction between T cells and thymic neurons. Interestingly, loss of T cell development results in a lack of thymic neuron development indicating T cell-neuron coregulation during development. However, thymic neurons can be recovered following a bone marrow transplant, suggesting the provision of a differentiation and/or survival signal for neurons provided by the developing T cells. Using knockout mice lacking the T cell lineage at various stages of development, we determined that TCR beta selection is required for the development of thymic neurons. Finally, we determined that a lack of transition from DN4 to DP severely diminishes the development of thymic neurons. Analysis of the publicly available bulk RNA-sequencing data comparing thymic DP to DN cell populations indicates the potential involvement of IL34 in neuronal development in the thymus. Conclusion We describe a novel population of neuronal cells within the thymus that interact with developing thymocytes to establish optimal thymic architecture. Funding Source NIH K99/R00 Topic Categories Neuroimmunology (NEUR)

Abstract Introduction Mucosal immunization and respiratory IgA offer significant promise in protecting against airborne pathogens, including SARS-CoV-2. However, the conditions and mechanisms that lead to the robust induction of respiratory IgA responses following mucosal vaccination remain poorly understood. Methods In this project, we established SARS-CoV-2 breakthrough infection and mucosal adenovirus-based booster vaccination models. Using genetic mouse models and various in vivo and in vitro blockade or depletion approaches, we further investigated the mechanisms regulating respiratory IgA responses. Results Here we found that a mucosal adenovirus-based booster vaccination in mouse models revealed that respiratory booster immunization elicited markedly stronger and more durable respiratory IgA, T cell response, and protective immunity against SARS-CoV-2, supporting the promise of respiratory mucosal vaccination. Mechanistically, we identified that local CD4+ T cells support respiratory IgA production by promoting IgA+ B cell class switching, proliferation, and survival in situ. This T cell help depended on interactions between local Blimp-1+ T-bet+ Th1 cells and B cells, mediated through ICOS/CD40L/MHC-II engagement and IL-21 signaling. Furthermore, lung macrophages contributed to the mucosal IgA response via TGF-β production. Consequently, mucosal administration of SARS-CoV-2 Spike-encoding mRNA encapsulated in pulmonary surfactant (PS)- incorporated lipid nanoparticles designed to target lung macrophages elicited a stronger mucosal IgA response. Conclusion Our results uncover a local cellular network supporting enhanced mucosal IgA responses, with implications for the development of optimal mucosal immunization strategies against SARS-CoV-2 and other respiratory pathogens such as H5N1 influenza. Funding Source AI147394, AG069264, AI112844, HL170961, AI154598, AI176171 to J.S., AI67986, AI177467 to Hui.H; U54CA260582 to S.L.L; R01AI168684 to G. Z.; S.L.L was also supported by a fund provided by an anonymous private donor to The Ohio State University. Topic Categories Mucosal and Regional Immunology (MUC)

Abstract Introduction The H-2Db class I restricted CD8 T cell response is critical for clearance of neurotropic Theiler’s virus encephalomyelitis virus (TMEV) infection. However, the key central nervous system cell types required to present H-2Db for CD8 T cell trafficking and expansion in the brain are not known. Mural cells are a critical cellular component of the neurovascular unit for maintaining vascular integrity which also express MHC class I molecules. However, the importance of mural cell antigen-restricted engagement by CD8 T cells has not been investigated. Methods To determine the function of mural cell MHC Class I antigen presentation, we crossed the Pdgfrβ-creERT2 mouse to our novel H-2Db LoxP mouse developed by our laboratory. This transgenic mouse approach enabled us to target mural cells during neuroinflammation. Results We observed robust knockdown of H-2Db on mural cells during acute TMEV infection. Conditional H-2Db knockdown in mural cells resulted in increased brain infiltration of CD8 T cells specific to the immunodominant Db:VP2 121-130 epitope of TMEV, demonstrating an important role of mural cells for immune cell recruitment. Conclusion To our knowledge, this is the first study demonstrating MHC class I antigen presentation by mural cells impacts CD8 T cell recruitment during neuroinflammation. Funding Source R01-NS103212, T32-AI170478 Topic Categories Neuroimmunology (NEUR)

Abstract Introduction Glioblastoma (GBM) is the most aggressive primary brain tumor in adults with an incident rate of 12,000 cases in the United States every year. Current treatment options for these patients include surgical resection, radiation, and chemotherapy. Despite these conventional treatments, patients have a dismal prognosis mostly due to the inability to deliver therapeutic agents across the blood-brain barrier. In recent years, the use of oncolytic picornavirus has been employed as a novel virotherapy for GBM. We hypothesized that we could enhance antibody delivery to the brain through harnessing the immune response associated with this oncolytic virus. Prior work from our lab has shown that CD8 T cell engagement with MHC class I on brain endothelium induces CNS vascular permeability which is dependent on perforin. We therefore asked if picornavirus antigen specific CD8 T cells could enhance antibody delivery to the brain. Methods To test this, we evaluated the potential of activating MHC class I restricted CD8 T cells in vivo through intravenous administration of their cognate picornavirus antigens. Results We determined that this approach enhanced delivery of antibody to brain parenchyma. Importantly, antibody delivery to the brain was still enhanced when CD8 T cells lacked perforin expression which significantly reduced the toxicity of this combination approach. Conclusion These findings demonstrate that theCD8 T cell response towards virotherapy can be harnessed to promote delivery of therapeutic antibody to the brain. Funding Source NCI — R01 CA 94953 NINDS — R01 NS122174 NINDS —R01 NS103212 Mayo Clinic Graduate School of Biomedical sciences Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)

Abstract Introduction CD8 T cells are key immune cells in viral clearance, targeting infected cells following recognition of MHC class I restricted antigen presentation. Previous work has determined that microglia and perivascular macrophages are essential for normal CD8 T cell responses against neurotropic viral infection, indicating that cells at the neurovascular unit can act as antigen-presenting cells. However, the specific importance of microglia MHC class I restricted antigen presentation to brain-infiltrating CD8 T cells has been difficult to define. Methods To address this question, our laboratory generated novel single MHC Class I conditional knockout mice in which H-2Kb or H-2Db can be deactivated specifically in Tmem119+ microglia with tamoxifen administration. Recombinant Theiler’s murine encephalomyelitis virus (TMEV) encoding the model OVA antigen enabled analysis of virus antigen-specific CD8 T cells restricted to H-2Kb class I molecules while Daniel’s strain TMEV H-2Db class I molecules enabled analysis of Db:VP2 specific CD8 T cells. Results Our results revealed profound differences in the response of CD8 T cells upon deletion of MHC class I molecules on microglia. Conditional knockout of H-2Kb in Tmem119+ microglia reduced Kb:OVA epitope specific CD8 T cells in the brain compared to Cre negative littermate controls, and BrdU staining revealed differences in T cell proliferation. Meanwhile, mice with deletion of Db in Tmem119+ microglia had reduced levels of perforin in Db:VP2 CD8 T cells. Furthermore, in a model of CNS vascular disease, the deletion of H-2Db of Tmem119+ microglia reduced CD8 T cell numbers in the brain, as well as the blood-brain barrier (BBB) breakdown observed by a FITC albumin assay. Conclusion These findings demonstrate discrete roles for specific MHC Class I molecules on microglia during CNS viral infection. This data will further our understanding of brain infiltrating CD8 T cell responses in neurologic diseases as well as the regulation of BBB by microglia. Funding Source R01 NS 103212 R01 NS122174 Topic Categories Neuroimmunology (NEUR)