Browsing by Author "Segal, Mark S."

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    Conditional Deletion of Bmal1 Accentuates Microvascular and Macrovascular Injury
    (Elsevier, 2017-06) Bhatwadekar, Ashay D.; Beli, Eleni; Diao, Yanpeng; Chen, Jonathan; Luo, Qianyi; Alex, Alpha; Caballero, Sergio; Dominguez, James M., II; Salazar, Tatiana E.; Busik, Julia V.; Segal, Mark S.; Grant, Maria B.; Ophthalmology, School of Medicine
    The brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein (BMAL)-1 constitutes a major transcriptional regulator of the circadian clock. Here, we explored the impact of conditional deletion of Bmal1 in endothelium and hematopoietic cells in murine models of microvascular and macrovascular injury. We used two models of Bmal1fx/fx;Tek-Cre mice, a retinal ischemia/reperfusion model and a neointimal hyperplasia model of the femoral artery. Eyes were enumerated for acellular capillaries and were stained for oxidative damage markers using nitrotyrosine immunohistochemistry. LSK (lineage-negative, stem cell antigen-1-positive, c-Kit-positive) cells were quantified and proliferation assessed. Hematopoiesis is influenced by innervation to the bone marrow, which we assessed using IHC analysis. The number of acellular capillaries increased threefold, and nitrotyrosine staining increased 1.5-fold, in the retinas of Bmal1fx/fx;Tek-Cre mice. The number of LSK cells from the Bmal1fx/fx;Tek-Cre mice decreased by 1.5-fold and was accompanied by a profound decrease in proliferative potential. Bmal1fx/fx;Tek-Cre mice also exhibited evidence of bone marrow denervation, demonstrating a loss of neurofilament-200 staining. Injured femoral arteries showed a 20% increase in neointimal hyperplasia compared with similarly injured wild-type controls. Our study highlights the importance of the circadian clock in maintaining vascular homeostasis and demonstrates that specific deletion of BMAL1 in endothelial and hematopoietic cells results in phenotypic features similar to those of diabetes.
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    Existing Transplant Nephrology Compensation Models and Opportunities for Equitable Pay
    (Wolters Kluwer, 2022) Josephson, Michelle A.; Wiseman, Alexander C.; Tucker, J. Kevin; Segal, Mark S.; Schmidt, Rebecca J.; Mujtaba, Muhammad A.; Gurley, Susan B.; Gaston, Robert S.; Doshi, Mona D.; Brennan, Daniel C.; Moe, Sharon M.; Medicine, School of Medicine
    The American Society of Nephrology (ASN) formed the ASN Task Force on Academic Nephrologist Compensation and Productivity in 2020 to understand how the subspecialty is evolving and where there are needs for alignment in compensation in US transplant centers. The task force's review of the roles and responsibilities of transplant nephrologists is in the companion perspective (1). Transplant nephrologists are required for successful kidney transplantation, the ideal treatment from a survival and quality-of-life perspective for patients with kidney failure (2,3). Unfortunately, work relative value unit (wRVU) requirements for compensation models vary tremendously across institutions and limit the ability to adequately staff programs. This article addresses transplant nephrology models of care, how different models affect funds flow and compensation, and opportunities to more equitably compensate transplant nephrologists.
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    The Importance of Transplant Nephrology to a Successful Kidney Transplant Program
    (Wolters Kluwer, 2022) Moe, Sharon M.; Brennan, Daniel C.; Doshi, Mona D.; Gaston, Robert S.; Gurley, Susan B.; Mujtaba, Muhammad A.; Schmidt, Rebecca J.; Segal, Mark S.; Tucker, J. Kevin; Wiseman, Alexander C.; Josephson, Michelle A.; Medicine, School of Medicine
    Nephrologists are responsible for the care of patients with a diverse array of systemic diseases, comorbidities, and kidney issues across a variety of service locations (clinic, inpatient, dialysis unit). As the field of nephrology becomes increasingly complex, there has been a need for advanced training and subspecialization, similar to the transformation cardiology experienced with heart failure, electrophysiology, and interventional cardiology. As a result, the American Society of Nephrology (ASN) formed the ASN Task Force on Academic Nephrologist Compensation and Productivity to begin to understand the needed transformation, especially as it relates to assessing clinical productivity and compensation. Members of the task force included nephrology division chiefs, transplant program directors, and transplant nephrologists, representing academic and community transplant programs across the United States. The group met virtually throughout 2021 to discuss specific job functions, roles, responsibilities, and compensation models, and the discussion and conclusions follow. The flow of transplant funds from the hospital to the physician and transplant nephrology models of care are further discussed in a companion Perspective.