Browsing by Author "Himmelfarb, Jonathan"

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    A Metabolomics Approach to Identify Metabolites Associated With Mortality in Patients Receiving Maintenance Hemodialysis
    (Elsevier, 2024-06-29) Al Awadhi, Solaf; Myint, Leslie; Guallar, Eliseo; Clish, Clary B.; Wulczyn, Kendra E.; Kalim, Sahir; Thadhani, Ravi; Segev, Dorry L.; McAdams DeMarco, Mara; Moe, Sharon M.; Moorthi, Ranjani N.; Hostetter, Thomas H.; Himmelfarb, Jonathan; Meyer, Timothy W.; Powe, Neil R.; Tonelli, Marcello; Rhee, Eugene P.; Shafi, Tariq; Medicine, School of Medicine
    Introduction: Uremic toxins contributing to increased risk of death remain largely unknown. We used untargeted metabolomics to identify plasma metabolites associated with mortality in patients receiving maintenance hemodialysis. Methods: We measured metabolites in serum samples from 522 Longitudinal US/Canada Incident Dialysis (LUCID) study participants. We assessed the association between metabolites and 1-year mortality, adjusting for age, sex, race, cardiovascular disease, diabetes, body mass index, serum albumin, Kt/Vurea, dialysis duration, and country. We modeled these associations using limma, a metabolite-wise linear model with empirical Bayesian inference, and 2 machine learning (ML) models: Least absolute shrinkage and selection operator (LASSO) and random forest (RF). We accounted for multiple testing using a false discovery rate (pFDR) adjustment. We defined significant mortality-metabolite associations as pFDR < 0.1 in the limma model and metabolites of at least medium importance in both ML models. Results: The mean age of the participants was 64 years, the mean dialysis duration was 35 days, and there were 44 deaths (8.4%) during a 1-year follow-up period. Two metabolites were significantly associated with 1-year mortality. Quinolinate levels (a kynurenine pathway metabolite) were 1.72-fold higher in patients who died within year 1 compared with those who did not (pFDR, 0.009), wheras mesaconate levels (an emerging immunometabolite) were 1.57-fold higher (pFDR, 0.002). An additional 42 metabolites had high importance as per LASSO, 46 per RF, and 9 per both ML models but were not significant per limma. Conclusion: Quinolinate and mesaconate were significantly associated with a 1-year risk of death in incident patients receiving maintenance hemodialysis. External validation of our findings is needed.
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    A Participant-Centered Approach to Understanding Risks and Benefits of Participation in Research Informed by the Kidney Precision Medicine Project
    (Elsevier, 2022) Butler, Catherine R.; Appelbaum, Paul S.; Ascani, Heather; Aulisio, Mark; Campbell, Catherine E.; de Boer, Ian H.; Dighe, Ashveena L.; Hall, Daniel E.; Himmelfarb, Jonathan; Knight, Richard; Mehl, Karla; Murugan, Raghavan; Rosas, Sylvia E.; Sedor, John R.; O'Toole, John F.; Tuttle, Katherine R.; Waikar, Sushrut S.; Freeman, Michael; Kidney Precision Medicine Project; Medicine, School of Medicine
    An understanding of the ethical underpinnings of human subjects research that involves some risk to participants without anticipated direct clinical benefit-such as the kidney biopsy procedure as part of the Kidney Precision Medicine Project (KPMP)-requires a critical examination of the risks as well as the diverse set of countervailing potential benefits to participants. This kind of deliberation has been foundational to the development and conduct of the KPMP. Herein, we use illustrative features of this research paradigm to develop a more comprehensive conceptualization of the types of benefits that may be important to research participants, including respecting pluralistic values, supporting the opportunity to act altruistically, and enhancing benefits to a participant's community. This approach may serve as a model to help researchers, ethicists, and regulators to identify opportunities to better respect and support participants in future research that entails some risk to these participants as well as to improve the quality of research for people with kidney disease.
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    Precision Medicine in Nephrology: An Integrative Framework of Multidimensional Data in the Kidney Precision Medicine Project
    (Elsevier, 2024) El-Achkar, Tarek M.; Eadon, Michael T.; Kretzler, Matthias; Himmelfarb, Jonathan; Kidney Precision Medicine Project; Medicine, School of Medicine
    Chronic kidney disease (CKD) and acute kidney injury (AKI) are heterogeneous syndromes defined clinically by serial measures of kidney function. Each condition possesses strong histopathologic associations, including glomerular obsolescence or acute tubular necrosis, respectively. Despite such characterization, there remains wide variation in patient outcomes and treatment responses. Precision medicine efforts, as exemplified by the Kidney Precision Medicine Project (KPMP), have begun to establish evolving, spatially anchored, cellular and molecular atlases of the cell types, states, and niches of the kidney in health and disease. The KPMP atlas provides molecular context for CKD and AKI disease drivers and will help define subtypes of disease that are not readily apparent from canonical functional or histopathologic characterization but instead are appreciable through advanced clinical phenotyping, pathomic, transcriptomic, proteomic, epigenomic, and metabolomic interrogation of kidney biopsy samples. This perspective outlines the structure of the KPMP, its approach to the integration of these diverse datasets, and its major outputs relevant to future patient care.
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    Prevalence and Persistence of Uremic Symptoms in Incident Dialysis Patients
    (ASN, 2020-02-01) Rhee, Eugene P.; Guallar, Eliseo; Hwang, Seungyoung; Kim, Noori; Tonelli, Marcello; Moe, Sharon M.; Himmelfarb, Jonathan; Thadhani, Ravi I.; Powe, Neil R.; Shafi, Tariq; Medicine, School of Medicine
    Background Uremic symptoms are major contributors to the poor quality of life among patients on dialysis, but whether their prevalence or intensity has changed over time is unknown. Methods We examined responses to validated questionnaires in two incident dialysis cohort studies, the Choices for Health Outcomes in Caring for ESRD (CHOICE) study (N=926, 1995–1998) and the Longitudinal United States/Canada Incident Dialysis (LUCID) study (N=428, 2011–2017). We determined the prevalence and severity of uremic symptoms—anorexia, nausea/vomiting, pruritus, sleepiness, difficulty concentrating, fatigue, and pain—in both cohorts. Results In CHOICE and LUCID, respectively, mean age of the participants was 58 and 60 years, 53% and 60% were male, and 28% and 32% were black. In both cohorts, 54% of the participants had diabetes. Median time from dialysis initiation to the symptoms questionnaires was 45 days for CHOICE and 77 days for LUCID. Uremic symptom prevalence in CHOICE did not change from baseline to 1-year follow-up and was similar across CHOICE and LUCID. Baseline symptom prevalence in CHOICE and LUCID was as follows: anorexia (44%, 44%, respectively), nausea/vomiting (36%, 43%), pruritus (72%, 63%), sleepiness (86%, 68%), difficulty concentrating (55%, 57%), fatigue (89%, 77%), and pain (82%, 79%). In both cohorts, >80% of patients had three or more symptoms and >50% had five or more symptoms. The correlation between individual symptoms was low (ρ<0.5 for all comparisons). In CHOICE, no clinical or laboratory parameter was strongly associated with multiple symptoms. Conclusions The burden of uremic symptoms among patients on dialysis is substantial and has not changed in the past 15 years. Improving quality of life will require identification of the factors that underlie the pathogenesis of uremic symptoms and better ways of removing the toxins that are responsible.
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    Rationale and design of the Kidney Precision Medicine Project
    (Elsevier, 2021) de Boer, Ian H.; Alpers, Charles E.; Azeloglu, Evren U.; Balis, Ulysses G. J.; Barasch, Jonathan M.; Barisoni, Laura; Blank, Kristina N.; Bomback, Andrew S.; Brown, Keith; Dagher, Pierre C.; Dighe, Ashveena L.; Eadon, Michael T.; El-Achkar, Tarek M.; Gaut, Joseph P.; Hacohen, Nir; He, Yongqun; Hodgin, Jeffrey B.; Jain, Sanjay; Kellum, John A.; Kiryluk, Krzysztof; Knight, Richard; Laszik, Zoltan G.; Lienczewski, Chrysta; Mariani, Laura H.; McClelland, Robyn L.; Menez, Steven; Moledina, Dennis G.; Mooney, Sean D.; O'Toole, John F.; Palevsky, Paul M.; Parikh, Chirag R.; Poggio, Emilio D.; Rosas, Sylvia E.; Rosengart, Matthew R.; Sarwal, Minnie M.; Schaub, Jennifer A.; Sedor, John R.; Sharma, Kumar; Steck, Becky; Toto, Robert D.; Troyanskaya, Olga G.; Tuttle, Katherine R.; Vazquez, Miguel A.; Waikar, Sushrut S.; Williams, Kayleen; Wilson, Francis Perry; Zhang, Kun; Iyengar, Ravi; Kretzler, Matthias; Himmelfarb, Jonathan; Kidney Precision Medicine Project; Medicine, School of Medicine
    Chronic kidney disease (CKD) and acute kidney injury (AKI) are common, heterogeneous, and morbid diseases. Mechanistic characterization of CKD and AKI in patients may facilitate a precision-medicine approach to prevention, diagnosis, and treatment. The Kidney Precision Medicine Project aims to ethically and safely obtain kidney biopsies from participants with CKD or AKI, create a reference kidney atlas, and characterize disease subgroups to stratify patients based on molecular features of disease, clinical characteristics, and associated outcomes. An additional aim is to identify critical cells, pathways, and targets for novel therapies and preventive strategies. This project is a multicenter prospective cohort study of adults with CKD or AKI who undergo a protocol kidney biopsy for research purposes. This investigation focuses on kidney diseases that are most prevalent and therefore substantially burden the public health, including CKD attributed to diabetes or hypertension and AKI attributed to ischemic and toxic injuries. Reference kidney tissues (for example, living-donor kidney biopsies) will also be evaluated. Traditional and digital pathology will be combined with transcriptomic, proteomic, and metabolomic analysis of the kidney tissue as well as deep clinical phenotyping for supervised and unsupervised subgroup analysis and systems biology analysis. Participants will be followed prospectively for 10 years to ascertain clinical outcomes. Cell types, locations, and functions will be characterized in health and disease in an open, searchable, online kidney tissue atlas. All data from the Kidney Precision Medicine Project will be made readily available for broad use by scientists, clinicians, and patients.
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    A reference tissue atlas for the human kidney
    (American Association for the Advancement of Science, 2022) Hansen, Jens; Sealfon, Rachel; Menon, Rajasree; Eadon, Michael T.; Lake, Blue B.; Steck, Becky; Anjani, Kavya; Parikh, Samir; Sigdel, Tara K.; Zhang, Guanshi; Velickovic, Dusan; Barwinska, Daria; Alexandrov, Theodore; Dobi, Dejan; Rashmi, Priyanka; Otto, Edgar A.; Rivera, Miguel; Rose, Michael P.; Anderton, Christopher R.; Shapiro, John P.; Pamreddy, Annapurna; Winfree, Seth; Xiong, Yuguang; He, Yongqun; de Boer, Ian H.; Hodgin, Jeffrey B.; Barisoni, Laura; Naik, Abhijit S.; Sharma, Kumar; Sarwal, Minnie M.; Zhang, Kun; Himmelfarb, Jonathan; Rovin, Brad; El-Achkar, Tarek M.; Laszik, Zoltan; He, John Cijiang; Dagher, Pierre C.; Valerius, M. Todd; Jain, Sanjay; Satlin, Lisa M.; Troyanskaya, Olga G.; Kretzler, Matthias; Iyengar, Ravi; Azeloglu, Evren U.; Kidney Precision Medicine Project; Medicine, School of Medicine
    Kidney Precision Medicine Project (KPMP) is building a spatially specified human kidney tissue atlas in health and disease with single-cell resolution. Here, we describe the construction of an integrated reference map of cells, pathways, and genes using unaffected regions of nephrectomy tissues and undiseased human biopsies from 56 adult subjects. We use single-cell/nucleus transcriptomics, subsegmental laser microdissection transcriptomics and proteomics, near-single-cell proteomics, 3D and CODEX imaging, and spatial metabolomics to hierarchically identify genes, pathways, and cells. Integrated data from these different technologies coherently identify cell types/subtypes within different nephron segments and the interstitium. These profiles describe cell-level functional organization of the kidney following its physiological functions and link cell subtypes to genes, proteins, metabolites, and pathways. They further show that messenger RNA levels along the nephron are congruent with the subsegmental physiological activity. This reference atlas provides a framework for the classification of kidney disease when multiple molecular mechanisms underlie convergent clinical phenotypes.
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    The chromatin landscape of healthy and injured cell types in the human kidney
    (Springer Nature, 2024-01-10) Gisch, Debora L.; Brennan, Michelle; Lake, Blue B.; Basta, Jeannine; Keller, Mark S.; Ferreira, Ricardo Melo; Akilesh, Shreeram; Ghag, Reetika; Lu, Charles; Cheng, Ying-Hua; Collins, Kimberly S.; Parikh, Samir V.; Rovin, Brad H.; Robbins, Lynn; Stout, Lisa; Conklin, Kimberly Y.; Diep, Dinh; Zhang, Bo; Knoten, Amanda; Barwinska, Daria; Asghari, Mahla; Sabo, Angela R.; Ferkowicz, Michael J.; Sutton, Timothy A.; Kelly, Katherine J.; De Boer, Ian H.; Rosas, Sylvia E.; Kiryluk, Krzysztof; Hodgin, Jeffrey B.; Alakwaa, Fadhl; Winfree, Seth; Jefferson, Nichole; Türkmen, Aydın; Gaut, Joseph P.; Gehlenborg, Nils; Phillips, Carrie L.; El-Achkar, Tarek M.; Dagher, Pierre C.; Hato, Takashi; Zhang, Kun; Himmelfarb, Jonathan; Kretzler, Matthias; Mollah, Shamim; Kidney Precision Medicine Project (KPMP); Jain, Sanjay; Rauchman, Michael; Eadon, Michael T.; Medicine, School of Medicine
    There is a need to define regions of gene activation or repression that control human kidney cells in states of health, injury, and repair to understand the molecular pathogenesis of kidney disease and design therapeutic strategies. Comprehensive integration of gene expression with epigenetic features that define regulatory elements remains a significant challenge. We measure dual single nucleus RNA expression and chromatin accessibility, DNA methylation, and H3K27ac, H3K4me1, H3K4me3, and H3K27me3 histone modifications to decipher the chromatin landscape and gene regulation of the kidney in reference and adaptive injury states. We establish a spatially-anchored epigenomic atlas to define the kidney's active, silent, and regulatory accessible chromatin regions across the genome. Using this atlas, we note distinct control of adaptive injury in different epithelial cell types. A proximal tubule cell transcription factor network of ELF3, KLF6, and KLF10 regulates the transition between health and injury, while in thick ascending limb cells this transition is regulated by NR2F1. Further, combined perturbation of ELF3, KLF6, and KLF10 distinguishes two adaptive proximal tubular cell subtypes, one of which manifested a repair trajectory after knockout. This atlas will serve as a foundation to facilitate targeted cell-specific therapeutics by reprogramming gene regulatory networks.