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Medical researchers have called for new forms of translational science that can solve complex medical problems. Mainstream science has made complementary calls for heterogeneous teams of collaborators who conduct transdisciplinary research so as to solve c

UnlabelledThe mycophenolate mofetil (MMF) trial involved 650 heart transplant patients from 28 centers who received MMF or azathioprine (AZA), both in combination with cyclosporine and corticosteroids. Baseline and 1-year intravascular ultrasound (IVUS) were performed in 196 patients (102 MMF and 94 AZA) with no differences between groups in IVUS results analyzed by morphometric analysis (average of 10 evenly spaced sites, without matching sites between studies). Baseline to first-year IVUS data can also be analyzed by site-to-site analysis (matching sites between studies), which has been reported to be more clinically relevant. Therefore, we used site-to-site analysis to reanalyze the multicenter MMF IVUS data.ResultsIVUS images were reviewed and interpretable in 190 patients (99 MMF and 91 AZA) from the multicenter randomized trial. The AZA group compared to the MMF group had a larger number of patients with first-year maximal intimal thickness (MIT)>or=0.3 mm (43% vs. 23%, p=0.005), a greater decrease in the mean lumen area (p=0.02) and a decrease in the mean vessel area (the area actually increased in the MMF group, p=0.03).ConclusionMMF-treated heart transplant patients compared to AZA-treated patients, both concurrently on cyclosporine and corticosteroids, in this study have significantly less progression of first-year intimal thickening.

Background: There is significant variability amongst pathologists in the histopathological interpretation of the endomyocardial biopsy (EMB) for acute cellular rejection (ACR) and assessment of variability in the interpretation of antibody-mediated rejection (AMR) has not been reported. In contemporary practice, the strategy of allograft surveillance with donor-derived cell-free DNA (dd-cfDNA) as compared to EMB has not been compared with a focus on long-term clinical outcomes beyond acute rejection (AR)., Methods: The Genomic Research Alliance for Transplantation (GRAfT) is a multicenter, prospective cohort study that enrolled patients from 2015 to 2020. The center pathologist read was compared to two blinded core cardiac pathologists. ACR and AMR were graded based on the International Society for Heart and Lung Transplantation (ISHLT) criteria. Weighted Cohen's kappa (κ) was used to evaluate interrater reliability between the center and core reads. To assess long-term outcomes, we evaluated a composite of AR, allograft dysfunction, and mortality within 1 year., Results: The study included 94 patients (median age 55 years [IQR 45, 62]), 30% female, 41% Black race) with a total of 429 EMBs and paired dd-cfDNA measures. The concordance rate between center and core pathologists was 77% for ACR (95%CI: 66% - 89%) and 63% for AMR (95%CI: 53% - 74%). 46 patients had an elevation in dd-cfDNA without AR by EMB. The median dd-cfDNA was 0.49% (IQR: 0.35, 1.01) and subsequent AR, allograft dysfunction, or mortality occurred in 59% of these patients at 1 year. In patients with AR by EMB and negative dd-cfDNA (n=5) the composite outcome occurred in 20% of patients at 1 year. At baseline, the positive likelihood ratio (LR+) of dd-cfDNA to detect AR by the center pathologist was 3.74 (95% CI 3.01 - 4.64) and core pathologist was 2.59 (95%CI: 1.95 - 3.45). If the composite outcome was included as a true positive, the LR+ of dd-cfDNA improved to 9.82 (95%CI: 7.04, 13.69) and7.63 (95% CI: 5.61, 10.38) at 1-year, respectively., Conclusions: Pathologists interrater reliability is limited in both ACR and AMR. The positive LR of dd-cfDNA when compared to traditional histopathology is limited, but when longitudinal clinical outcomes are included to assess diagnostic performance, the LR+ improves significantly. The value of dd-cfDNA extends beyond the diagnosis of AR to include other clinically meaningful outcomes for patients after heart transplant., (Copyright © 2024. Published by Elsevier Inc.)

Background: Noninvasive methods for surveillance of acute rejection are increasingly used in heart transplantation (HT), including donor-derived cell-free DNA (dd-cfDNA). As other cardiac biomarkers differ by sex, we hypothesized that there may be sex-specific differences in the performance of dd-cfDNA for the detection of acute rejection. The purpose of the current study was to examine patterns of dd-cfDNA seen in quiescence and acute rejection in male and female transplant recipients., Methods: Patients enrolled in the Genomic Research Alliance for Transplantation who were ≥18 years at the time of HT were included. Rejection was defined by endomyocardial biopsy with acute cellular rejection (ACR) grade ≥2R and/or antibody-mediated rejection ≥ pAMR 1. dd-cfDNA was quantitated using shotgun sequencing. Median dd-cfDNA levels were compared between sexes during quiescence and rejection. The performance of dd-cfDNA by sex was assessed using area under the receiver operator characteristic (AUROC) curve. Allograft injury was defined as dd-cfDNA ≥0.25%., Results: One hundred fifty-one unique patients (49 female, 32%) were included in the analysis with 1,119 available dd-cfDNA measurements. Baseline characteristics including demographics and comorbidities were not significantly different between sexes. During quiescence, there were no significant sex differences in median dd-cfDNA level (0.04% [IQR 0.00, 0.16] in females vs 0.03% [IQR 0.00, 0.12] in males, p = 0.22). There were no significant sex differences in median dd-cfDNA for ACR (0.33% [0.21, 0.36] in females vs 0.32% [0.21, 1.10] in males, p = 0.57). Overall, median dd-cfDNA levels were higher in antibody-mediated rejection (AMR) than ACR but did not significantly differ by sex (0.50% [IQR 0.18, 0.82] in females vs 0.63% [IQR 0.32, 1.95] in males, p = 0.51). Elevated dd-cfDNA detected ACR/AMR with an AUROC of 0.83 in females and 0.89 in males, p-value for comparison = 0.16., Conclusions: There were no significant sex differences in dd-cfDNA levels during quiescence and rejection. Performance characteristics were similar, suggesting similar diagnostic thresholds can be used in men and women for rejection surveillance., (Copyright © 2024 International Society for the Heart and Lung Transplantation. All rights reserved.)

Background: Black heart transplant patients are at higher risk of acute rejection (AR) and death than White patients. We hypothesized that this risk may be associated with higher levels of donor-derived cell-free DNA (dd-cfDNA) and cell-free mitochondrial DNA., Methods: The Genomic Research Alliance for Transplantation is a multicenter, prospective, longitudinal cohort study. Sequencing was used to quantitate dd-cfDNA and polymerase chain reaction to quantitate cell-free mitochondrial DNA in plasma. AR was defined as ≥2R cellular rejection or ≥1 antibody-mediated rejection. The primary composite outcome was AR, graft dysfunction (left ventricular ejection fraction <50% and decrease by ≥10%), or death., Results: We included 148 patients (65 Black patients and 83 White patients), median age was 56 years and 30% female sex. The incidence of AR was higher in Black patients compared with White patients (43% versus 19%; P =0.002). Antibody-mediated rejection occurred predominantly in Black patients with a prevalence of 20% versus 2% ( P <0.001). After transplant, Black patients had higher levels of dd-cfDNA, 0.09% (interquartile range, 0.001-0.30) compared with White patients, 0.05% (interquartile range, 0.001-0.23; P =0.003). Beyond 6 months, Black patients showed a persistent rise in dd-cfDNA with higher levels compared with White patients. Cell-free mitochondrial DNA was higher in Black patients (185 788 copies/mL; interquartile range, 101 252-422 133) compared with White patients (133 841 copies/mL; interquartile range, 75 346-337 990; P <0.001). The primary composite outcome occurred in 43% and 55% of Black patients at 1 and 2 years, compared with 23% and 27% in White patients, P <0.001. In a multivariable model, Black patient race (hazard ratio, 2.61 [95% CI, 1.35-5.04]; P =0.004) and %dd-cfDNA (hazard ratio, 1.15 [95% CI, 1.03-1.28]; P =0.010) were associated with the primary composite outcome., Conclusions: Elevated dd-cfDNA and cell-free mitochondrial DNA after heart transplant may mechanistically be implicated in the higher incidence of AR and worse clinical outcomes in Black transplant recipients., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02423070., Competing Interests: Disclosures Dr P. Shah has unrelated grant support paid to the institution from Merck, Bayer, Roche, and Abbott and participated in consulting for Natera, Merck, and Procyrion. Dr K. Shah is a consultant for Eidos and Grant Reviewer for Pfizer. Dr Valantine participated in Board of Directors for CareDx. The other authors report no conflicts.

Competing Interests: Disclosures Dr Valantine serves on the board of directors of CareDx, Inc., Pacific Biosciences, Inc., and Bridge Biosciences, and is a senior advisor to the Chan Zuckerberg Initiative. Dr Khush is a scientific advisor, research grant recipient, and speaker for CareDx, Inc.

Dr. Hannah Valantine is renowned for her work in transplantation medicine, leadership, and mentoring as well as her efforts to improve scientific workforce diversity. In this interview with Cell, she discusses her research; what Juneteenth means to her; the persistent gender, race, and ethnicity leadership gaps that exist in academic medicine; and the importance of equitable, inclusive, and diverse science., Competing Interests: Declaration of interests H.A.V. serves on the board of directors of Pacific Biosciences Inc., Bridgebio Inc., and CareDx Inc. H.A.V. also serves as a consultant to the Chan Zuckerberg Initiative., (Copyright © 2023.)

An extensive body of research about team science provides empirical evidence that diverse teams outperform homogenous teams in creating more innovative solutions to complex problems. At the core of diverse and inclusive teams is a rich diversity of perspectives, experiences, and backgrounds that invite new questions and broaden the scope of research. Diverse perspectives are especially relevant for biomedicine, which seeks to find solutions for challenging problems affecting the human condition. It is essential that diversity and inclusion in biomedicine is prioritized as a key driver of innovation, both through the people who conduct the research and the science itself. Key questions have been articulated as important drivers for funding research: (1) Who is doing the science and who is building the tools? (2) What science and technology is being done and how? and (3) Who has access to the knowledge and benefits of scientific innovation? I will briefly review the empirical evidence supporting diversity as a powerful enhancer of the quality and outputs of research and clinical care. I offer my own research as a case study of incorporating a framework of diversity, equity, and inclusion into research that uses new emerging genomic tools for earlier and more precise diagnosis of organ transplant rejection. I will demonstrate how these same tools hold great promise for accelerating the discovery of hitherto unexplored mechanisms that drive the poor outcomes for African ancestry organ transplant recipients, which in turn will identify new diagnostics and therapeutic targets that benefit transplant recipients across all ancestries., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Cell-free DNA (cfDNA) is a noninvasive marker of cellular injury. Its significance in pulmonary arterial hypertension (PAH) is unknown., Methods: Plasma cfDNA was measured in 2 PAH cohorts (A, n=48; B, n=161) and controls (n=48). Data were collected for REVEAL 2.0 (Registry to Evaluate Early and Long-Term PAH Disease Management) scores and outcome determinations. Patients were divided into the following REVEAL risk groups: low (≤6), medium (7-8), and high (≥9). Total cfDNA concentrations were compared among controls and PAH risk groups by 1-way analysis of variance. Log-rank tests compared survival between cfDNA tertiles and REVEAL risk groups. Areas under the receiver operating characteristic curve were estimated from logistic regression models. A sample subset from cohort B (n=96) and controls (n=16) underwent bisulfite sequencing followed by a deconvolution algorithm to map cell-specific cfDNA methylation patterns, with concentrations compared using t tests., Results: In cohort A, median (interquartile range) age was 62 years (47-71), with 75% female, and median (interquartile range) REVEAL 2.0 was 6 (4-9). In cohort B, median (interquartile range) age was 59 years (49-71), with 69% female, and median (interquartile range) REVEAL 2.0 was 7 (6-9). In both cohorts, cfDNA concentrations differed among patients with PAH of varying REVEAL risk and controls (analysis of variance P ≤0.002) and were greater in the high-risk compared with the low-risk category ( P ≤0.002). In cohort B, death or lung transplant occurred in 14 of 54, 23 of 53, and 35 of 54 patients in the lowest, middle, and highest cfDNA tertiles, respectively. cfDNA levels stratified as tertiles (log-rank: P =0.0001) and REVEAL risk groups (log-rank: P <0.0001) each predicted transplant-free survival. The addition of cfDNA to REVEAL improved discrimination (area under the receiver operating characteristic curve, 0.72-0.78; P =0.02). Compared with controls, methylation analysis in patients with PAH revealed increased cfDNA originating from erythrocyte progenitors, neutrophils, monocytes, adipocytes, natural killer cells, vascular endothelium, and cardiac myocytes (Bonferroni adjusted P <0.05). cfDNA concentrations derived from erythrocyte progenitor cells, cardiac myocytes, and vascular endothelium were greater in patients with PAH with high-risk versus low-risk REVEAL scores ( P ≤0.02)., Conclusions: Circulating cfDNA is elevated in patients with PAH, correlates with disease severity, and predicts worse survival. Results from cfDNA methylation analyses in patients with PAH are consistent with prevailing paradigms of disease pathogenesis.

Background: Noninvasive monitoring of heart allograft health is important to improve clinical outcomes. MicroRNAs (miRs) are promising biomarkers of cardiovascular disease and limited studies suggest they can be used to noninvasively diagnose acute heart transplant rejection., Methods: The Genomic Research Alliance for Transplantation (GRAfT) is a multicenter prospective cohort study that phenotyped heart transplant patients from 5 mid-Atlantic centers. Patients who had no history of rejection after transplant were compared to patients with acute cellular rejection (ACR) or antibody-mediated rejection (AMR). Small RNA sequencing was performed on plasma samples collected at the time of an endomyocardial biopsy. Differential miR expression was performed with adjustment for clinical covariates. Regression was used to develop miR panels with high diagnostic accuracy for ACR and AMR. These panels were then validated in independent samples from GRAfT and Stanford University. Receiver operating characteristic curves were generated and area under the curve (AUC) statistics calculated. Distinct ACR and AMR clinical scores were developed to translate miR expression data for clinical use., Results: The GRAfT cohort had a median age of 52 years, with 35% females and 45% Black patients. Between GRAfT and Stanford, we included 157 heart transplant patients: 108 controls and 49 with rejection (50 ACR and 38 AMR episodes). After differential miR expression and regression analysis, we identified 12 miRs that accurately discriminate ACR and 17 miRs in AMR. Independent validation of the miR panels within GRAfT led to an ACR AUC 0.92 (95% confidence interval [CI]: 0.86-0.98) and AMR AUC 0.82 (95% CI: 0.74-0.90). The externally validated ACR AUC was 0.72 (95% CI: 0.59-0.82). We developed distinct ACR and AMR miR clinical scores (range 0-100), a score ≥ 65, identified ACR with 86% sensitivity, 76% specificity, and 98% negative predictive value, for AMR score performance was 82%, 84% and 97%, respectively., Conclusions: We identified novel miRs that had excellent performance to noninvasively diagnose acute rejection after heart transplantation. Once rigorously validated, the unique clinical ACR and AMR scores usher in an era whereby genomic biomarkers can be used to screen and diagnose the subtype of rejection. These novel biomarkers may potentially alleviate the need for an endomyocardial biopsy while facilitating the initiation of targeted therapy based on the noninvasive diagnosis of ACR or AMR., (Copyright © 2022 International Society for Heart and Lung Transplantation. All rights reserved.)

Black patients suffer higher rates of antibody-mediated rejection and have worse long-term graft survival after heart transplantation. Donor-derived cell free DNA (ddcfDNA) is released into the blood following allograft injury. This study analyzed %ddcfDNA in 63 heart transplant recipients categorized by Black and non-Black race, during the first 200 days after transplant. Immediately after transplant, %ddcfDNA was higher for Black patients (mean [SE]: 8.3% [1.3%] vs 3.2% [1.2%], p = 0.001). In the first week post-transplant, the rate of decay in %ddcfDNA was similar (0.7% [0.68] vs 0.7% [0.11], p = 0.78), and values declined in both groups to a comparable plateau at 7 days post-transplant (0.46% [0.03] vs 0.45% [0.04], p = 0.78). The proportion of Black patients experiencing AMR was higher than non-Black patients (21% vs 9% [hazard ratio of 2.61 [95% confidence interval: 0.651-10.43], p = 0.18). Black patients were more likely to receive a race mismatched organ than non-Black patients (69% vs 35%, p = 0.01), which may explain the higher levels of early allograft injury., (Copyright © 2022. Published by Elsevier Inc.)

Workplace harassment, particularly sexual harassment, has substantial negative implications for individuals and organizations and for scientific advancement. The National Institutes of Health (NIH) is uniquely positioned to lead the effort to prevent sexual harassment in the scientific community and mitigate its detrimental effects. Recognizing the need for benchmark data, NIH developed and validated the 2019 NIH Workplace Climate and Harassment Survey. The goal was to use best practices in survey design methods to create an instrument for rigorous assessment of harassment incidence and organizational climate predictors of sexual harassment in scientific research environments. This article summarizes the processes used to design and administer the NIH survey and provides brief descriptions of 3 products of the process developed to guide scientific institutions wishing to embark on a data-driven approach to assess and prevent harassment: a document detailing survey development and methods, a survey implementation guide, and the key findings obtained from the survey, including recommendations for interventions targeting the organizational climate at NIH and limitations of the survey. The survey identified that 1 in 5 respondents had experienced sexual harassment in the 12 months preceding their participation in the survey and that women, sexual and gender minorities, younger respondents, trainees/students, and individuals with a disability were more likely to have experienced sexual harassment. Those who had experienced sexual harassment during that period were also more likely to have experienced incivility, bullying, and intimidating behaviors in the workplace. NIH intends to use the survey findings as a quality assurance and quality improvement guide to inform future activities to prevent and address harassment across NIH., (Copyright © 2021 by the Association of American Medical Colleges.)

Background: After heart transplantation, endomyocardial biopsy (EMBx) is used to monitor for acute rejection (AR). Unfortunately, EMBx is invasive, and its conventional histological interpretation has limitations. This is a validation study to assess the performance of a sensitive blood biomarker-percent donor-derived cell-free DNA (%ddcfDNA)-for detection of AR in cardiac transplant recipients., Methods: This multicenter, prospective cohort study recruited heart transplant subjects and collected plasma samples contemporaneously with EMBx for %ddcfDNA measurement by shotgun sequencing. Histopathology data were collected to define AR, its 2 phenotypes (acute cellular rejection [ACR] and antibody-mediated rejection [AMR]), and controls without rejection. The primary analysis was to compare %ddcfDNA levels (median and interquartile range [IQR]) for AR, AMR, and ACR with controls and to determine %ddcfDNA test characteristics using receiver-operator characteristics analysis., Results: The study included 171 subjects with median posttransplant follow-up of 17.7 months (IQR, 12.1-23.6), with 1392 EMBx, and 1834 %ddcfDNA measures available for analysis. Median %ddcfDNA levels decayed after surgery to 0.13% (IQR, 0.03%-0.21%) by 28 days. Also, %ddcfDNA increased again with AR compared with control values (0.38% [IQR, 0.31-0.83%], versus 0.03% [IQR, 0.01-0.14%]; P <0.001). The rise was detected 0.5 and 3.2 months before histopathologic diagnosis of ACR and AMR. The area under the receiver operator characteristic curve for AR was 0.92. A 0.25%ddcfDNA threshold had a negative predictive value for AR of 99% and would have safely eliminated 81% of EMBx. In addition, %ddcfDNA showed distinctive characteristics comparing AMR with ACR, including 5-fold higher levels (AMR ≥2, 1.68% [IQR, 0.49-2.79%] versus ACR grade ≥2R, 0.34% [IQR, 0.28-0.72%]), higher area under the receiver operator characteristic curve (0.95 versus 0.85), higher guanosine-cytosine content, and higher percentage of short ddcfDNA fragments., Conclusions: We found that %ddcfDNA detected AR with a high area under the receiver operator characteristic curve and negative predictive value. Monitoring with ddcfDNA demonstrated excellent performance characteristics for both ACR and AMR and led to earlier detection than the EMBx-based monitoring. This study supports the use of %ddcfDNA to monitor for AR in patients with heart transplant and paves the way for a clinical utility study. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02423070.

In nearly all walks of life, leadership sets the tone for what gets done, who does it, and how it is achieved. In 2020, the top ranks of academic medicine have not yet attained gender parity-an aspirational goal set 7 years ago in this journal as "50:50 by 2020," and a vital aim for the United States' productivity and innovation as a leader in biomedical research. Parity in academic leadership for women and other groups underrepresented in science and medicine will seed the culture change necessary for inclusive excellence: environments in which individuals from all backgrounds thrive in their pursuit of new knowledge to benefit human health.In this Invited Commentary, the author describes the National Institutes of Health's (NIH's) current system-wide framework and tools for creating cultures of inclusive excellence through a set of guiding principles and integrated strategies. Successful efforts will recognize that individually focused solutions are necessary but not sufficient for institutional culture change. In keeping with a systems approach are implementing accountability and transparency; establishing clear metrics of inclusion, diversity, and equity; tracking and evaluating such metrics; as well as tying these metrics to institutional reward systems. These essential steps to institutional culture transformation require strong partnerships between NIH and the academic community. The author argues that with committed vision, focus, and energy, success is attainable, and soon.

The representation of women and scientists from underrepresented groups (URGs), including Black/African Americans, Hispanic/Latinx, Pacific Islanders, and American Indians, diminishes as individuals advance in their careers from training to senior leadership positions. Correcting this imbalance requires integrated strategies to achieve inclusive excellence within the scientific workforce reflected by creating and sustaining environments, in which diverse talent thrives. The National Institutes of Health (NIH) Scientific Workforce Diversity office has led the charge to develop and implement evidence-informed interventions toward achieving this goal that undergirds NIH's mission to improve the nation's health. Past and current efforts aiming to enhance workforce diversity but targeted to individuals are necessary but insufficient for lasting change. Thus, NIH-funded institutions should develop and prioritize integrated, systems-targeted efforts as foundational components of a well-supported, productive workforce. At the heart of these endeavors is institutional accountability that ties progress toward inclusive excellence to institutional values and reward systems., (© 2020 Federation of American Societies for Experimental Biology.)

Despite efforts to promote diversity in the biomedical workforce, there remains a lower rate of funding of National Institutes of Health R01 applications submitted by African-American/black (AA/B) scientists relative to white scientists. To identify underlying causes of this funding gap, we analyzed six stages of the application process from 2011 to 2015 and found that disparate outcomes arise at three of the six: decision to discuss, impact score assignment, and a previously unstudied stage, topic choice. Notably, AA/B applicants tend to propose research on topics with lower award rates. These topics include research at the community and population level, as opposed to more fundamental and mechanistic investigations; the latter tend to have higher award rates. Topic choice alone accounts for over 20% of the funding gap after controlling for multiple variables, including the applicant's prior achievements. Our findings can be used to inform interventions designed to close the funding gap., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

Background: Acute allograft rejection (AAR) plays an important role in patient and graft survival; therefore, more emphasis should be placed on its prediction. This study aimed to investigate baseline clinical and diagnostic variables associated with subsequent AAR during the first year post-transplant, especially focusing on early physiologic and anatomic measures., Methods: This study enrolled 88 heart transplant patients who underwent fractional flow reserve (FFR), coronary flow reserve (CFR), the index of microcirculatory resistance (IMR) and intravascular ultrasound (IVUS) in the left anterior descending artery at baseline (within 8 weeks post-transplant). Cardiac index (CI), pulmonary capillary wedge pressure (PCWP), mean pulmonary artery pressure (mPAP), right atrial pressure and left ventricular ejection fraction were also evaluated. AAR was defined as acute cellular rejection of grade ≥2R and/or pathological antibody-mediated rejection of grade ≥pAMR2., Results: During the first year post-transplant, 25.0% of patients experienced AAR. Patients with AAR during the first year showed higher rates of recipient obesity, lower rates of recipient-donor sex mismatch and rATG and tacrolimus uses, higher PCWP, mPAP and IMR, and lower CFR at baseline, compared with those without. In the multivariate analysis, only baseline IMR ≥ 16.0 was independently associated with AAR during the first year, demonstrating high negative predictive value (96.7%)., Conclusions: Invasively assessing microvascular resistance (baseline IMR ≥ 16.0) in the early post-transplant period was an independent determinant of subsequent acute allograft rejection during the first year post-transplant, suggesting that early assessment of IMR may enhance patient risk stratification and target medical therapies to improve patient outcome., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Allograft failure is common in lung-transplant recipients and leads to poor outcomes including early death. No reliable clinical tools exist to identify patients at high risk for allograft failure. This study tested the use of donor-derived cell-free DNA (%ddcfDNA) as a sensitive marker of early graft injury to predict impending allograft failure., Methods: This multicenter, prospective cohort study enrolled 106 subjects who underwent lung transplantation and monitored them after transplantation for the development of allograft failure (defined as severe chronic lung allograft dysfunction [CLAD], retransplantation, and/or death from respiratory failure). Plasma samples were collected serially in the first three months following transplantation and assayed for %ddcfDNA by shotgun sequencing. We computed the average levels of ddcfDNA over three months for each patient (avddDNA) and determined its relationship to allograft failure using Cox-regression analysis., Findings: avddDNA was highly variable among subjects: median values were 3·6%, 1·6% and 0·7% for the upper, middle, and low tertiles, respectively (range 0·1%-9·9%). Compared to subjects in the low and middle tertiles, those with avddDNA in the upper tertile had a 6·6-fold higher risk of developing allograft failure (95% confidence interval 1·6-19·9, p = 0·007), lower peak FEV1 values, and more frequent %ddcfDNA elevations that were not clinically detectable., Interpretation: Lung transplant patients with early unresolving allograft injury measured via %ddcfDNA are at risk of subsequent allograft injury, which is often clinically silent, and progresses to allograft failure. FUND: National Institutes of Health., (Published by Elsevier B.V.)

Background: Antibody-mediated rejection (AMR) often progresses to poor health outcomes in lung transplant recipients (LTRs). This, combined with the relatively insensitive clinical tools used for its diagnosis (spirometry, histopathology) led us to determine whether clinical AMR is diagnosed significantly later than its pathologic onset. In this study, we leveraged the high sensitivity of donor-derived cell-free DNA (ddcfDNA), a novel genomic tool, to detect early graft injury after lung transplantation., Methods: We adjudicated AMR and acute cellular rejection (ACR) in 157 LTRs using the consensus criteria of the International Society for Heart and Lung Transplantation (ISHLT). We assessed the kinetics of allograft injury in relation to ACR or AMR using both clinical criteria (decline in spirometry from baseline) and molecular criteria (ddcfDNA); percent ddcfDNA was quantitated via shotgun sequencing. We used a mixed-linear model to assess the relationship between and ddcfDNA levels and donor-specific antibodies (DSA) in AMR + LTRs., Results: Compared with ACR, AMR episodes (n = 42) were associated with significantly greater allograft injury when assessed by both spirometric (0.1 liter vs -0.6 liter, p < 0.01) and molecular (ddcfDNA) analysis (1.1% vs 5.4%, p < 0.001). Allograft injury detected by ddcfDNA preceded clinical AMR diagnosis by a median of 2.8 months. Within the same interval, spirometry or histopathology did not reveal findings of allograft injury or dysfunction. Elevated levels of ddcfDNA before clinical diagnosis of AMR were associated with a concurrent rise in DSA levels., Conclusion: Diagnosis of clinical AMR in LTRs lags behind DSA-associated molecular allograft injury as assessed by ddcfDNA., (Copyright © 2018. Published by Elsevier Inc.)

Background: Invasively assessed coronary microvascular resistance early after heart transplantation predicts worse long-term outcome; however, little is known about the relationship between microvascular resistance, left ventricular function and outcomes in this setting., Methods: A total of 100 cardiac transplant recipients had fractional flow reserve (FFR) and the index of microcirculatory resistance (IMR) measured in the left anterior descending artery and echocardiographic assessment of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) at 1 year after heart transplantation. The primary endpoint was the composite of death and retransplantation occurring beyond the first post-operative year., Results: The mean FFR, IMR, LVEF, and GLS values at 1 year were 0.87 ± 0.06, 21.3 ± 17.3, 60.4 ± 5.4%, and 14.2 ± 2.4%, respectively. FFR and IMR had no significant correlation with LVEF and GLS. During a mean follow-up of 6.7 ± 4.2 years, the primary endpoint occurred in 24 patients (24.0%). By ROC curve analysis, IMR = 19.3 and GLS = 13.3% were the best cutoff values for predicting death or retransplantation. Cumulative event-free survival was significantly lower in patients with higher IMR (log-rank p = 0.02) and lower GLS (log-rank p < 0.001). Cumulative event-free survival can be further stratified by the combination of IMR and GLS (long-rank p < 0.001). By multivariable Cox proportional hazards model, higher IMR and lower GLS were independently associated with long-term death or retransplantation (elevated IMR, hazard ratio = 2.50, p = 0.04 and reduced GLS, hazard ratio = 3.79, p = 0.003, respectively)., Conclusion: Invasively assessed IMR does not correlate with GLS at 1 year after heart transplantation. IMR and GLS determined at 1 year may be used as independent predictors of late death or retransplantation., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The first spark of my desire to become a cardiologist came, believe it or not, in a third-grade art class where I was asked to draw and color the circulation of blood as depicted by 16th-century English physician William Harvey. This task enraptured me-seeing that something so beautiful could work so flawlessly. So, many years later, I remain intrigued by cardiac transplantation, the subspecialty in which I ultimately chose to anchor my career as a physician scientist. Each day I live in awe of the fact that you can remove someone's organ, place it in another, and still have that organ work beautifully, most of the time. But why does it sometimes fail?

Cardiac allograft vasculopathy is a major cause of long-term graft failure following heart transplantation. Asymmetric dimethylarginine (ADMA), a marker of endothelial dysfunction, has been mechanistically implicated in the development of cardiac allograft vasculopathy, but its impact on coronary physiology early after transplantation is unknown. Invasive indices of coronary physiology, namely, fractional flow reserve (FFR), the index of microcirculatory resistance, and coronary flow reserve, were measured with a coronary pressure wire in the left anterior descending artery within 8 weeks (baseline) and 1 year after transplant. Plasma levels of ADMA were concurrently assayed using high-performance liquid chromatography. In 46 heart transplant recipients, there was a statistically significant correlation between elevated ADMA levels and lower FFR values at baseline (r = -0.33; p = 0.024); this modest association persisted 1 year after transplant (r = -0.39; p = 0.0085). Patients with a baseline FFR <0.90 (a prognostically validated cutoff) had significantly higher baseline ADMA levels (0.63 ± 0.16 vs 0.54 ± 0.12 µM; p = 0.034). Baseline ADMA (odds ratio 1.80 per 0.1 µM; 95% confidence interval 1.07 to 3.03; p = 0.027) independently predicted a baseline FFR <0.90 after multivariable adjustment. Even after dichotomizing ADMA (≥0.60 µM, provides greatest diagnostic accuracy by receiver operating characteristic curve), this association remained significant (odds ratio 7.52, 95% confidence interval 1.74 to 32.49; p = 0.006). No significant relationship between ADMA and index of microcirculatory resistance or coronary flow reserve was detected. In conclusion, baseline ADMA was a strong independent predictor of FFR <0.90, suggesting that elevated ADMA levels are associated with abnormal epicardial function soon after heart transplantation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Negative remodeling is a common occurrence early after cardiac transplantation. Its impact on the development of myocardial ischemia is not well documented. The aim of this study is to investigate the impact of negative remodeling on fractional flow reserve after cardiac transplantation., Methods: Thirty-four cardiac transplant recipients underwent intravascular ultrasound (IVUS) and fractional flow reserve (FFR) assessment soon after transplantation and one year later. Patients were divided into those with and without negative remodeling based on IVUS, and the impact on FFR was assessed. In the 19 patients with negative remodeling, there was no significant change in plaque volume (119.3±82.0 to 131.3±91.2mm 3 , p=0.21), but vessel volume (775.6±212.0 to 621.9±144.1mm 3 , p<0.0001) and lumen volume (656.3±169.1 to 490.7±132.0mm 3 , p<0.0001) decreased significantly and FFR likewise decreased significantly (0.88±0.06 to 0.84±0.07, p=0.04). In the 15 patients without negative remodeling, vessel volume did not change (711.7±217.6 to 745.7±198.5, p=0.28), but there was a significant increase in plaque volume (126.8±88.3 to 194.4±92.7, p<0.001) and a resultant significant decrease in FFR (0.89±0.05 to 0.85±0.05, p=0.01)., Conclusion: Negative remodeling itself, without any change in plaque volume can cause a significant decrease in fractional flow reserve after cardiac transplantation and appears to be another possible mechanism for myocardial ischemia., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Cardiac allograft vasculopathy (CAV) remains a leading cause of mortality after heart transplantation (HT). Angiotensin-converting enzyme inhibitors (ACEIs) may retard the development of CAV but have not been well studied after HT., Objectives: This study tested the safety and efficacy of the ACEI ramipril on the development of CAV early after HT., Methods: In this prospective, multicenter, randomized, double-blind, placebo-controlled trial, 96 HT recipients were randomized to undergo ramipril or placebo therapy. They underwent coronary angiography, endothelial function testing; measurements of fractional flow reserve (FFR) and coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR); and intravascular ultrasonography (IVUS) of the left anterior descending coronary artery, within 8 weeks of HT. At 1 year, the invasive assessment was repeated. Circulating endothelial progenitor cells (EPCs) were quantified at baseline and 1 year., Results: Plaque volumes at 1 year were similar between the ramipril and placebo groups (162.1 ± 70.5 mm 3 vs. 177.3 ± 94.3 mm 3 , respectively; p = 0.73). Patients receiving ramipril had improvement in microvascular function as shown by a significant decrease in IMR (21.4 ± 14.7 to 14.4 ± 6.3; p = 0.001) and increase in CFR (3.8 ± 1.7 to 4.8 ± 1.5; p = 0.017), from baseline to 1 year. This did not occur with IMR (17.4 ± 8.4 to 21.5 ± 20.0; p = 0.72) or CFR (4.1 ± 1.8 to 4.1 ± 2.2; p = 0.60) in the placebo-treated patients. EPCs decreased significantly at 1 year in the placebo group but not in the ramipril group., Conclusions: Ramipril does not slow development of epicardial plaque volume but does stabilize levels of endothelial progenitor cells and improve microvascular function, which have been associated with improved long-term survival after HT. (Angiotensin Converting Enzyme [ACE] Inhibition and Cardiac Allograft Vasculopathy; NCT01078363)., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

The National Institutes of Health (NIH) is committed to attracting, developing, and supporting the best scientists from all groups as an integral part of excellence in training. Biomedical research workforce diversity, capitalizing on the full spectrum of skills, talents, and viewpoints, is essential for solving complex human health challenges. Over the past few decades, the biomedical research workforce has benefited from NIH programs aimed at enhancing diversity. However, there is considerable room for improvement, particularly at the level of independent scientists and within scientific leadership. We provide a rationale and specific opportunities to develop and sustain a diverse biomedical research workforce through interventions that promote the successful transitions to different stages on the path toward completion of training and entry into the biomedical workforce., (© 2016 H. A. Valantine et al. CBE—Life Sciences Education © 2016 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).)

Background: Although cardiac allograft vasculopathy (CAV) is typically characterized by diffuse coronary intimal thickening with pathological vessel remodeling, plaque instability may also play an important role in CAV. Previous studies of native coronary atherosclerosis have demonstrated associations between attenuated-signal plaque (ASP), plaque instability, and adverse clinical events., Objectives: This study's aim was to characterize the association between ASP and long-term mortality post-heart transplantation., Methods: In 105 heart transplant recipients, serial (baseline and 1-year post-transplant) intravascular ultrasound was performed in the first 50 mm of the left anterior descending artery. The ASP score was calculated by grading the measured angle of attenuation from grades 0 to 4 (specifically, 0°, 1° to 90°, 91° to 180°, 181° to 270°, and >270°) at 1-mm intervals. The primary endpoint was all-cause death or retransplantation., Results: At 1-year post-transplant, 10.5% of patients demonstrated ASP progression (newly developed or increased ASP). Patients with ASP progression had a higher incidence of acute cellular rejection during the first year (63.6% vs. 22.3%; p = 0.006) and tendency for greater intimal growth (percent intimal volume: 9.2 ± 9.3% vs. 4.4 ± 5.3%; p = 0.07) than those without. Over a median follow-up of 4.6 years, there was a significantly lower event-free survival rate in patients with ASP progression at 1-year post-transplant compared with those without. In contrast, maximum intimal thickness did not predict long-term mortality., Conclusions: ASP progression appears to reflect chronic inflammation related to acute cellular rejection and is an independent predictor of long-term mortality after heart transplantation. Serial assessments of plaque instability may enhance identification of high-risk patients who may benefit from closer follow-up and targeted medical therapies., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Circulating cell-free DNA (cfDNA) is emerging as a powerful monitoring tool in cancer, pregnancy and organ transplantation. Nucleosomal DNA, the predominant form of plasma cfDNA, can be adapted for sequencing via ligation of double-stranded DNA (dsDNA) adapters. dsDNA library preparations, however, are insensitive to ultrashort, degraded cfDNA. Drawing inspiration from advances in paleogenomics, we have applied a single-stranded DNA (ssDNA) library preparation method to sequencing of cfDNA in the plasma of lung transplant recipients (40 samples, six patients). We found that ssDNA library preparation yields a greater portion of sub-100 bp nuclear genomic cfDNA (p 10(-5), Mann-Whitney U Test), and an increased relative abundance of mitochondrial (10.7x, p 10(-5)) and microbial cfDNA (71.3x, p 10(-5)). The higher yield of microbial sequences from this method increases the sensitivity of cfDNA-based monitoring for infections following transplantation. We detail the fragmentation pattern of mitochondrial, nuclear genomic and microbial cfDNA over a broad fragment length range. We report the observation of donor-specific mitochondrial cfDNA in the circulation of lung transplant recipients. A ssDNA library preparation method provides a more informative window into understudied forms of cfDNA, including mitochondrial and microbial derived cfDNA and short nuclear genomic cfDNA, while retaining information provided by standard dsDNA library preparation methods.

Objectives: This study investigated the association between arterial remodeling and geographic distribution of cardiac allograft vasculopathy (CAV), and outcomes after heart transplantation., Background: CAV is characterized by a combination of coronary intimal thickening and pathological vessel remodeling, which varies at different locations in coronary arteries., Methods: In 100 transplant recipients, serial volumetric intravascular ultrasonography (IVUS) was performed at baseline and 1 year post-transplantation in the first 50 mm of the left anterior descending artery (LAD). IVUS indices were evaluated in the entire segment and 3 equally divided LAD segments. Paradoxical vessel remodeling was defined as [Δvessel volume/Δintimal volume <0]., Results: After 1 year, death or re-transplantation occurred in 20 patients over a median follow-up period of 4.7 years. Paradoxical vessel remodeling was observed in 57%, 41%, 50%, and 40% for the entire vessel, proximal, middle, and distal LAD segments, respectively. Kaplan-Meier analysis revealed a significantly lower event-free rate of survival in patients with paradoxical vessel remodeling involving the proximal LAD segment, which was not present when involving the entire LAD or mid and distal LAD segments. In multivariate analysis, paradoxical vessel remodeling of the proximal LAD segment was independently associated with death or re-transplantation (hazard ratio [HR]: 11.18; 95% confidence interval [CI]: 2.39 to 83.23; p = 0.0015)., Conclusions: Despite the diffuse nature of CAV, paradoxical vessel remodeling of the proximal LAD segment at 1 year was the primary determinant of long-term mortality or re-transplantation. Assessment of arterial remodeling combined with coronary intimal thickening may enhance identification of high-risk patients who may benefit from closer follow-up and targeted medical therapies., (Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: It remains difficult to predict and to measure the efficacy of pharmacological immunosuppression. We hypothesized that measuring the B-cell repertoire would enable assessment of the overall level of immunosuppression after heart transplantation., Methods and Findings: In this proof-of-concept study, we implemented a molecular-barcode-based immune repertoire sequencing assay that sensitively and accurately measures the isotype and clonal composition of the circulating B cell repertoire. We used this assay to measure the temporal response of the B cell repertoire to immunosuppression after heart transplantation. We selected a subset of 12 participants from a larger prospective cohort study (ClinicalTrials.gov NCT01985412) that is ongoing at Stanford Medical Center and for which enrollment started in March 2010. This subset of 12 participants was selected to represent post-heart-transplant events, with and without acute rejection (six participants with moderate-to-severe rejection and six without). We analyzed 130 samples from these patients, with an average follow-up period of 15 mo. Immune repertoire sequencing enables the measurement of a patient's net state of immunosuppression (correlation with tacrolimus level, r = -0.867, 95% CI -0.968 to -0.523, p = 0.0014), as well as the diagnosis of acute allograft rejection, which is preceded by increased immune activity with a sensitivity of 71.4% (95% CI 30.3% to 94.9%) and a specificity of 82.0% (95% CI 72.1% to 89.1%) (cell-free donor-derived DNA as noninvasive gold standard). To illustrate the potential of immune repertoire sequencing to monitor atypical post-transplant trajectories, we analyzed two more patients, one with chronic infections and one with amyloidosis. A larger, prospective study will be needed to validate the power of immune repertoire sequencing to predict rejection events, as this proof-of-concept study is limited to a small number of patients who were selected based on several criteria including the availability of a large number of samples and the absence or presence of rejection events., Conclusions: If confirmed in larger, prospective studies, the method described here has potential applications in the tailored management of post-transplant immunosuppression and, more broadly, as a method for assessing the overall activity of the immune system.

The US biomedical research workforce does not currently mirror the nation's population demographically, despite numerous attempts to increase diversity. This imbalance is limiting the promise of our biomedical enterprise for building knowledge and improving the nation's health. Beyond ensuring fairness in scientific workforce representation, recruiting and retaining a diverse set of minds and approaches is vital to harnessing the complete intellectual capital of the nation. The complexity inherent in diversifying the research workforce underscores the need for a rigorous scientific approach, consistent with the ways we address the challenges of science discovery and translation to human health. Herein, we identify four cross-cutting diversity challenges ripe for scientific exploration and opportunity: research evidence for diversity's impact on the quality and outputs of science; evidence-based approaches to recruitment and training; individual and institutional barriers to workforce diversity; and a national strategy for eliminating barriers to career transition, with scientifically based approaches for scaling and dissemination. Evidence-based data for each of these challenges should provide an integrated, stepwise approach to programs that enhance diversity rapidly within the biomedical research workforce.