Biomarkers from subcutaneous engineered tissues predict acute rejection of organ allografts.

Invasive graft biopsies assess the efficacy of immunosuppression through lagging indicators of transplant rejection. We report on a microporous scaffold implant as a minimally invasive immunological niche to assay rejection before graft injury. Adoptive transfer of T cells into Rag2-/- mice with mismatched allografts induced acute cellular allograft rejection (ACAR), with subsequent validation in wild-type animals. Following murine heart or skin transplantation, scaffold implants accumulate predominantly innate immune cells. The scaffold enables frequent biopsy, and gene expression analyses identified biomarkers of ACAR before clinical signs of graft injury. This gene signature distinguishes ACAR and immunodeficient respiratory infection before injury onset, indicating the specificity of the biomarkers to differentiate ACAR from other inflammatory insult. Overall, this implantable scaffold enables remote evaluation of the early risk of rejection, which could potentially be used to reduce the frequency of routine graft biopsy, reduce toxicities by personalizing immunosuppression, and prolong transplant life.

Deactivation of LVAD Support for Myocardial Recovery - Surgical Perspectives.

Left ventricular assist devices (LVAD) are excellent therapies for advanced heart failure patients either bridged to transplant or for lifetime use. LVADs also allow for reverse remodeling of the failing heart that is often associated with functional improvement. Indeed, growing enthusiasm exists to better understand this population of patients whereby the LVAD is used as an adjunct to mediate myocardial recovery. When patients achieve benchmarks suggesting that they no longer need LVAD support, questions related to discontinuation of LVAD therapy become front and center. The purpose of this review is to provide a surgical perspective to the practical and technical issues surrounding LVAD deactivation.

The landscape of regional missense mutational intolerance quantified from 125,748 exomes.

Missense variants can have a range of functional impacts depending on factors such as the specific amino acid substitution and location within the gene. To interpret their deleteriousness, studies have sought to identify regions within genes that are specifically intolerant of missense variation 1-12 . Here, we leverage the patterns of rare missense variation in 125,748 individuals in the Genome Aggregation Database (gnomAD) 13 against a null mutational model to identify transcripts that display regional differences in missense constraint. Missense-depleted regions are enriched for ClinVar 14 pathogenic variants, de novo missense variants from individuals with neurodevelopmental disorders (NDDs) 15,16 , and complex trait heritability. Following ClinGen calibration recommendations for the ACMG/AMP guidelines, we establish that regions with less than 20% of their expected missense variation achieve moderate support for pathogenicity. We create a missense deleteriousness metric (MPC) that incorporates regional constraint and outperforms other deleteriousness scores at stratifying case and control de novo missense variation, with a strong enrichment in NDDs. These results provide additional tools to aid in missense variant interpretation.

The Scalable Variant Call Representation: Enabling Genetic Analysis Beyond One Million Genomes.

The Variant Call Format (VCF) is widely used in genome sequencing but scales poorly. For instance, we estimate a 150,000 genome VCF would occupy 900 TiB, making it both costly and complicated to produce and analyze. The issue stems from VCF's requirement to densely represent both reference-genotypes and allele-indexed arrays. These requirements lead to unnecessary data duplication and, ultimately, very large files. To address these challenges, we introduce the Scalable Variant Call Representation (SVCR). This representation reduces file sizes by ensuring they scale linearly with samples. SVCR achieves this by adopting reference blocks from the Genomic Variant Call Format (GVCF) and employing local allele indices. SVCR is also lossless and mergeable, allowing for N+1 and N+K incremental joint-calling. We present two implementations of SVCR: SVCR-VCF, which encodes SVCR in VCF format, and VDS, which uses Hail's native format. Our experiments confirm the linear scalability of SVCR-VCF and VDS, in contrast to the super-linear growth seen with standard VCF files. We also discuss the VDS Combiner, a scalable, open-source tool for producing a VDS from GVCFs and unique features of VDS which enable rapid data analysis. SVCR, and VDS in particular, ensure the scientific community can generate, analyze, and disseminate genetics datasets with millions of samples.

Use of Extracorporeal Membrane Oxygenation for Primary Graft Dysfunction After Cardiac Transplantation: Results of an A Priori Ventless Approach.

Primary graft dysfunction (PGD) after cardiac transplantation is a devastating complication with increasing frequency lately in the setting of donation after circulatory death (DCD). Severe PGD is commonly treated with extracorporeal membrane oxygenation (ECMO) using central or peripheral cannulation. We retrospectively reviewed the outcomes of PGD after cardiac transplantation requiring ECMO support at our center from 2015 to 2020, focused on our now preferential approach using peripheral cannulation without a priori venting. During the study period, 255 patients underwent heart transplantation at our center and 26 (10.2%) of them required ECMO for PGD. Of 24 patients cannulated peripherally 19 (79%) were alive at 30 days and 17 (71%) 1 year after transplant; two additional patients underwent central ECMO cannulation due to unfavorable size of femoral vessels and concern for limb ischemia. Successful decannulation with full graft function recovery occurred in 22 of 24 (92%) patients cannulated peripherally. Six of them had an indwelling intra-aortic balloon pump placed before the transplantation. None of the other 18 patients received a ventricular vent. In conclusion, the use of an a priori peripheral and ventless ECMO approach in patients with PGD after heart transplant is an effective strategy associated with high rates of graft recovery and survival.

Itaconate suppresses atherosclerosis by activating a Nrf2-dependent antiinflammatory response in macrophages in mice.

Itaconate has emerged as a critical immunoregulatory metabolite. Here, we examined the therapeutic potential of itaconate in atherosclerosis. We found that both itaconate and the enzyme that synthesizes it, aconitate decarboxylase 1 (Acod1, also known as immune-responsive gene 1 [IRG1]), are upregulated during atherogenesis in mice. Deletion of Acod1 in myeloid cells exacerbated inflammation and atherosclerosis in vivo and resulted in an elevated frequency of a specific subset of M1-polarized proinflammatory macrophages in the atherosclerotic aorta. Importantly, Acod1 levels were inversely correlated with clinical occlusion in atherosclerotic human aorta specimens. Treating mice with the itaconate derivative 4-octyl itaconate attenuated inflammation and atherosclerosis induced by high cholesterol. Mechanistically, we found that the antioxidant transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), was required for itaconate to suppress macrophage activation induced by oxidized lipids in vitro and to decrease atherosclerotic lesion areas in vivo. Overall, our work shows that itaconate suppresses atherogenesis by inducing Nrf2-dependent inhibition of proinflammatory responses in macrophages. Activation of the itaconate pathway may represent an important approach to treat atherosclerosis.

Projecting complete redaction of clinical trial protocols (RAPTURE): redacted cross sectional study.

OBJECTIVES: To characterise redactions in clinical trials and estimate a time when all protocols are fully removed (RAPTURE). DESIGN: Redacted cross sectional study. SETTING: Published phase 3 randomised controlled trials from 1 January 2010 to ██████████████. PARTICIPANTS: New England Journal of Medicine, ██████████, and Journal of the American Medical Association. MAIN OUTCOME MEASURES: █████ ████████ ██████████████ ██████ ██████████ ████████ ████████ ██████████ ███████████ ████████████ ████████████ ████████████████████████ ██████████████████ RESULTS: ████████████████████ met the inclusion criteria, with 268 (56.7%) research protocols available and accessible. The rate of redactions in protocols has increased from 0 in 2010 to 60.8% in 2021 (P<0.001). The degree of data redaction has also increased, with the average cumulative redactions among industry funded trials rising from 0 in 2010 to 3.5 pages in 2021 (P<0.001). Modelling predicts that RAPTURE is expected to occur between 2073 and 2136. Redactions featured predominantly in ████████ sponsored trials and mostly occurred in the statistical design. CONCLUSIONS: This study highlights the rise in protocol redactions and predicts that, ██████████████████████████████████████████ will be entirely redacted between 2073 and 2136. A legitimate rationale for the redactions could ███ be found. A multipronged strategy against protocol redactions is required to maintain the integrity of science. AVAILABILITY: This paper is partially redacted, but for the sake of ███████████, a version without any redactions can be found in the supplementary material.

Aspirin and Hemocompatibility Events With a Left Ventricular Assist Device in Advanced Heart Failure: The ARIES-HM3 Randomized Clinical Trial.

IMPORTANCE: Left ventricular assist devices (LVADs) enhance quality and duration of life in advanced heart failure. The burden of nonsurgical bleeding events is a leading morbidity. Aspirin as an antiplatelet agent is mandated along with vitamin K antagonists (VKAs) with continuous-flow LVADs without conclusive evidence of efficacy and safety. OBJECTIVE: To determine whether excluding aspirin as part of the antithrombotic regimen with a fully magnetically levitated LVAD is safe and decreases bleeding. DESIGN, SETTING, and PARTICIPANTS: This international, randomized, double-blind, placebo-controlled study of aspirin (100 mg/d) vs placebo with VKA therapy in patients with advanced heart failure with an LVAD was conducted across 51 centers with expertise in treating patients with advanced heart failure across 9 countries. The randomized population included 628 patients with advanced heart failure implanted with a fully magnetically levitated LVAD (314 in the placebo group and 314 in the aspirin group), of whom 296 patients in the placebo group and 293 in the aspirin group were in the primary analysis population, which informed the primary end point analysis. The study enrolled patients from July 2020 to September 2022; median follow-up was 14 months. Intervention: Patients were randomized in a 1:1 ratio to receive aspirin (100 mg/d) or placebo in addition to an antithrombotic regimen. MAIN OUTCOMES AND MEASURES: The composite primary end point, assessed for noninferiority (-10% margin) of placebo, was survival free of a major nonsurgical (>14 days after implant) hemocompatibility-related adverse events (including stroke, pump thrombosis, major bleeding, or arterial peripheral thromboembolism) at 12 months. The principal secondary end point was nonsurgical bleeding events. RESULTS: Of the 589 analyzed patients, 77% were men; one-third were Black and 61% were White. More patients were alive and free of hemocompatibility events at 12 months in the placebo group (74%) vs those taking aspirin (68%). Noninferiority of placebo was demonstrated (absolute between-group difference, 6.0% improvement in event-free survival with placebo [lower 1-sided 97.5% CI, -1.6%]; P < .001). Aspirin avoidance was associated with reduced nonsurgical bleeding events (relative risk, 0.66 [95% confidence limit, 0.51-0.85]; P = .002) with no increase in stroke or other thromboembolic events, a finding consistent among diverse subgroups of patient characteristics. CONCLUSIONS AND RELEVANCE: In patients with advanced heart failure treated with a fully magnetically levitated LVAD, avoidance of aspirin as part of an antithrombotic regimen, which includes VKA, is not inferior to a regimen containing aspirin, does not increase thromboembolism risk, and is associated with a reduction in bleeding events. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04069156.

Clonally expanded memory CD8+ T cells accumulate in atherosclerotic plaques and are pro-atherogenic in aged mice.

Aging is a strong risk factor for atherosclerosis and induces accumulation of memory CD8+ T cells in mice and humans. Biological changes that occur with aging lead to enhanced atherosclerosis, yet the role of aging on CD8+ T cells during atherogenesis is unclear. In this study, using femle mice, we found that depletion of CD8+ T cells attenuated atherogenesis in aged, but not young, animals. Furthermore, adoptive transfer of splenic CD8+ T cells from aged wild-type, but not young wild-type, donor mice significantly enhanced atherosclerosis in recipient mice lacking CD8+ T cells. We also characterized T cells in healthy and atherosclerotic young and aged mice by single-cell RNA sequencing. We found specific subsets of age-associated CD8+ T cells, including a Granzyme K+ effector memory subset, that accumulated and was clonally expanded within atherosclerotic plaques. These had transcriptomic signatures of T cell activation, migration, cytotoxicity and exhaustion. Overall, our study identified memory CD8+ T cells as therapeutic targets for atherosclerosis in aging.

Clinical Outcomes With a Fully Magnetically Levitated Left Ventricular Assist Device Among Women and Men.

BACKGROUND: Left ventricular assist devices (LVADs) are underused among women with advanced heart failure, but reasons remain unclear. Outcomes in women compared with men with contemporary fully magnetically levitated LVADs remain uncertain. OBJECTIVES: The authors examined differences in characteristics, 2-year outcomes, and risk for key adverse events among women and men. METHODS: In 2,200 HeartMate3 (HM3) (Abbott Cardiovascular) LVAD recipients in the MOMENTUM 3 study (Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy with HeartMate 3), survival free of disabling stroke or reoperation to replace or remove a malfunctioning pump at 2 years was analyzed between women and men. Other outcomes included overall 2-year survival, adverse events, and functional measures. RESULTS: Women comprised 20.4% (n = 448 of 2,200) of the study population and were younger, with nonischemic cardiomyopathy, and more often were Black persons compared with men. The primary endpoint (women 79.4% vs men 75.5% (adjusted [a]HR: 0.96 [95% CI: 0.75-1.24]; P = 0.66) or survival at 2 years (women 82.4% vs men 80.2%; aHR: 1.06 [95% CI: 0.81-1.40]; P = 0.66) was no different. Women had an increased rate of stroke (adjusted incidence rate ratio [aIRR]: 1.52 [95% CI: 1.09-2.11]; P = 0.012), major bleeding (aIRR: 1.28 [95% CI: 1.15-1.42]; P < 0.0001) and infection (aIRR 1.14 [95% CI: 1.03-1.55]; P = 0.01), but these differences were not seen among older (>65 years) patients. Both groups had similar gains in 6-minute walk distance and quality-of-life measurements. CONCLUSIONS: There were no differences in the primary composite endpoint or overall survival in women compared with men at 2 years of support. Reasons underlying increase in hemocompatibility-related events and infection-related morbidity in younger women deserves further study. (MOMENTUM 3 IDE [HM3], NCT02224755; MOMENTUM 3 Continued Access Protocol [MOMENTUM 3 CAP], NCT02892955).

Extended duration of treatment using reduced-frequency dosing of anti-PD-1 therapy in patients with advanced melanoma and Merkel cell carcinoma.

BACKGROUND: Optimal duration of treatment (DoT) with immune checkpoint inhibitors (ICI) in metastatic cancers remains unclear. Many patients, especially those without radiologic complete remission, develop progressive disease after ICI discontinuation. Extending DoT with ICI may potentially improve efficacy outcomes but presents major logistical and cost challenges with standard frequency dosing (SFD). Receptor occupancy data supports reduced frequency dosing (RFD) of anti-PD-1 antibodies, which may represent a more practical and economically viable option to extend DoT. METHODS: We conducted a retrospective study of patients with metastatic melanoma and Merkel cell carcinoma (MCC), who received ICI at RFD administered every 3 months, after initial disease control at SFD. We evaluated efficacy, safety, and cost-savings of the RFD approach in this cohort. RESULTS: Between 2014 and 2021, 23 patients with advanced melanoma (N = 18) or MCC (N = 5) received anti-PD-1 therapy at RFD. Median DoT was 1.1 years at SFD and 1.2 years at RFD. The 3 year PFS after start of RFD was 73% in melanoma and 100% in MCC patients, which compare favorably to historical control rates. In the subset of 15 patients who received at least 2 years of therapy, total savings amounted to $1.1 million in drug costs and 384 h saved despite the extended DoT (median 3.4 years), as compared to the calculated cost of 2 years at SFD. CONCLUSIONS: ICI administration at RFD can allow extension of treatment duration, while preserving efficacy and reducing logistical and financial burden. RFD approach deserves further exploration in prospective clinical trials.

Predictors of 5-Year Mortality in Patients Managed With a Magnetically Levitated Left Ventricular Assist Device.

BACKGROUND: In advanced heart failure patients implanted with a fully magnetically levitated HeartMate 3 (HM3, Abbott) left ventricular assist device (LVAD), it is unknown how preimplant factors and postimplant index hospitalization events influence 5-year mortality in those able to be discharged. OBJECTIVES: The goal was to identify risk predictors of mortality through 5 years among HM3 LVAD recipients conditional on discharge from index hospitalization in the MOMENTUM 3 pivotal trial. METHODS: This analysis evaluated 485 of 515 (94%) patients discharged after implantation of the HM3 LVAD. Preimplant (baseline), implant surgery, and index hospitalization characteristics were analyzed individually, and as multivariable predictors for mortality risk through 5 years. RESULTS: Cumulative 5-year mortality in the cohort (median age: 62 years, 80% male, 65% White, 61% destination therapy due to transplant ineligibility) was 38%. Two preimplant characteristics (elevated blood urea nitrogen and prior coronary artery bypass graft or valve procedure) and 3 postimplant characteristics (hemocompatibility-related adverse events, ventricular arrhythmias, and estimated glomerular filtration rate <60 mL/min/1.73 m2 at discharge) were predictors of 5-year mortality. In 171 of 485 patients (35.3%) without any risk predictors, 5-year mortality was reduced to 22.6% (95% CI: 15.4%-32.7%). Even among those with 1 or more predictors, mortality was <50% at 5 years (45.7% [95% CI: 39.0%-52.8%]). CONCLUSIONS: Long-term survival in successfully discharged HM3 LVAD recipients is largely influenced by clinical events experienced during the index surgical hospitalization in tandem with baseline factors, with mortality of <50% at 5 years. In patients without identified predictors of risk, long-term 5-year mortality is low and rivals that achieved with heart transplantation, even though most were implanted with destination therapy intent. (MOMENTUM 3 IDE Clinical Study Protocol, NCT02224755; MOMENTUM 3 Pivotal Cohort Extended Follow-up PAS, NCT03982979).

Interventional pharmacoeconomics for immune checkpoint inhibitors through alternative dosing strategies.

Immune checkpoint inhibitors (ICIs) are approved for the treatment of a variety of cancer types. The doses of these drugs, though approved by the Food and Drug Administration (FDA), have never been optimised, likely leading to significantly higher doses than required for optimal efficacy. Dose optimisation would hypothetically decrease the risk, severity, and duration of immune-related adverse events, as well as provide an opportunity to reduce costs through interventional pharmacoeconomic strategies such as off-label dose reductions or less frequent dosing. We summarise existing evidence for ICI dose optimisation to advocate for the role of interventional pharmacoeconomics.

An illusion of predictability in scientific results: Even experts confuse inferential uncertainty and outcome variability.

Traditionally, scientists have placed more emphasis on communicating inferential uncertainty (i.e., the precision of statistical estimates) compared to outcome variability (i.e., the predictability of individual outcomes). Here, we show that this can lead to sizable misperceptions about the implications of scientific results. Specifically, we present three preregistered, randomized experiments where participants saw the same scientific findings visualized as showing only inferential uncertainty, only outcome variability, or both and answered questions about the size and importance of findings they were shown. Our results, composed of responses from medical professionals, professional data scientists, and tenure-track faculty, show that the prevalent form of visualizing only inferential uncertainty can lead to significant overestimates of treatment effects, even among highly trained experts. In contrast, we find that depicting both inferential uncertainty and outcome variability leads to more accurate perceptions of results while appearing to leave other subjective impressions of the results unchanged, on average.

Lactate Dehydrogenase and Hemorrhagic Stroke During Extracorporeal Membrane Oxygenation for COVID-19.

PURPOSE: Hemorrhagic stroke (HS) is a devastating complication during extracorporeal membrane oxygenation (ECMO) but markers of risk stratification during COVID-19 are unknown. Lactate dehydrogenase (LDH) is a readily available biomarker of cell injury and permeability. We sought to determine whether an elevated LDH before ECMO placement is related to the occurrence of HS during ECMO for COVID-19. METHODS: Adult patients with COVID-19 requiring ECMO between March 2020 and February 2022 were included. LDH values prior to ECMO placement were captured. Patients were categorized into high (> 750 U/L) or low (≤ 750 U/L) LDH groups. Multivariable regression modeling was used to determine the association between LDH and HS during ECMO. RESULTS: There were 520 patients that underwent ECMO placement in 17 centers and 384 had an available LDH. Of whom, 122 (32%) had a high LDH. The overall incidence of HS was 10.9%, and patients with high LDH had a higher incidence of HS than those with low LDH level (17% vs 8%, p = 0.007). At 100 days, the probability of a HS was 40% in the high LDH group and 23% in those with a low LDH, p = 0.002. After adjustment for clinical covariates, high LDH remained associated with subsequent HS (aHR: 2.64, 95% CI 1.39-4.92). Findings were similar when restricting to patients supported by venovenous ECMO only. CONCLUSION: Elevated LDH prior to ECMO cannulation is associated with a higher incidence of HS during device support. LDH can risk stratify cases for impending cerebral bleeding during ECMO.