Browsing by Author "Ikizler, T. Alp"

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    Genetic Variants Associated With Mineral Metabolism Traits in Chronic Kidney Disease
    (Oxford University Press, 2022) Laster, Marciana L.; Rowan, Bryce; Chen, Hua-Chang; Schwantes-An, Tae-Hwi; Sheng, Xin; Friedman, Peter A.; Ikizler, T. Alp; Sinshiemer, Janet S.; Ix, Joachim H.; Susztak, Katalin; de Boer, Ian H.; Kestenbaum, Bryan; Hung, Adriana; Moe, Sharon M.; Perwad, Farzana; Robinson-Cohen, Cassianne; Medicine, School of Medicine
    Context: Chronic kidney disease (CKD) causes multiple interrelated disturbances in mineral metabolism. Genetic studies in the general population have identified common genetic variants associated with circulating phosphate, calcium, parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23). Objective: In this study we aimed to discover genetic variants associated with circulating mineral markers in CKD. Methods: We conducted candidate single-nucleotide variation (SNV) analysis in 3027 participants in the multiethnic Chronic Renal Insufficiency Cohort (CRIC) to determine the associations between SNVs and circulating levels of mineral markers. Results: SNVs adjacent to or within genes encoding the regulator of G protein-coupled signaling 14 (RGS14) and the calcium-sensing receptor (CASR) were associated with levels of mineral metabolites. The strongest associations (P < .001) were at rs4074995 (RGS14) for phosphate (0.09 mg/dL lower per minor allele) and FGF23 (8.6% lower), and at rs1801725 (CASR) for calcium (0.12 mg/dL higher). In addition, the prevalence of hyperparathyroidism differed by rs4074995 (RGS14) genotype (chi-square P < .0001). Differential inheritance by race was noted for the minor allele of RGS14. Expression quantitative loci (eQTL) analysis showed that rs4074995 was associated with lower RGS14 gene expression in glomeruli (P = 1.03 × 10-11) and tubules (P = 4.0 × 10-4). Conclusion: We evaluated genetic variants associated with mineral metabolism markers in a CKD population. Participants with CKD and the minor allele of rs4074995 (RGS14) had lower phosphorus, lower plasma FGF23, and lower prevalence of hyperparathyroidism. The minor allele of RGS14 was also associated with lower gene expression in the kidney. Further studies are needed to elucidate the effect of rs4074995 on the pathogenesis of disordered mineral metabolism in CKD.
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    Human and Machine Intelligence Together Drive Drug Repurposing in Rare Diseases
    (Frontiers Media, 2021-07-28) Challa, Anup P.; Zaleski, Nicole M.; Jerome, Rebecca N.; Lavieri, Robert R.; Shirey-Rice, Jana K.; Barnado, April; Lindsell, Christopher J.; Aronoff, David M.; Crofford, Leslie J.; Harris, Raymond C.; Ikizler, T. Alp; Mayer, Ingrid A.; Holroyd, Kenneth J.; Pulley, Jill M.; Medicine, School of Medicine
    Repurposing is an increasingly attractive method within the field of drug development for its efficiency at identifying new therapeutic opportunities among approved drugs at greatly reduced cost and time of more traditional methods. Repurposing has generated significant interest in the realm of rare disease treatment as an innovative strategy for finding ways to manage these complex conditions. The selection of which agents should be tested in which conditions is currently informed by both human and machine discovery, yet the appropriate balance between these approaches, including the role of artificial intelligence (AI), remains a significant topic of discussion in drug discovery for rare diseases and other conditions. Our drug repurposing team at Vanderbilt University Medical Center synergizes machine learning techniques like phenome-wide association study-a powerful regression method for generating hypotheses about new indications for an approved drug-with the knowledge and creativity of scientific, legal, and clinical domain experts. While our computational approaches generate drug repurposing hits with a high probability of success in a clinical trial, human knowledge remains essential for the hypothesis creation, interpretation, "go-no go" decisions with which machines continue to struggle. Here, we reflect on our experience synergizing AI and human knowledge toward realizable patient outcomes, providing case studies from our portfolio that inform how we balance human knowledge and machine intelligence for drug repurposing in rare disease.
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    Nutrition in Kidney Disease: Core Curriculum 2022
    (Elsevier, 2022-03) MacLaughlin, Helen L.; Friedman, Allon N.; Ikizler, T. Alp; Medicine, School of Medicine
    As chronic kidney disease (CKD) progresses, the requirements and utilization of different nutrients change substantially. These changes are accompanied by multiple nutritional and metabolic abnormalities that are observed in the continuum of kidney disease. To provide optimal care to patients with CKD, it is essential to have an understanding of the applicable nutritional principles: methods to assess nutritional status, establish patient-specific dietary needs, and prevent or treat potential or ongoing nutritional deficiencies and derangements. This installment of AJKD’s Core Curriculum in Nephrology provides current information on these issues for the practicing clinician and allied health care workers and features basic, practical information on epidemiology, assessment, etiology, and prevention and management of nutritional considerations in patients with kidney disease. Specific emphasis is made on dietary intake and recommendations for dietary patterns, and macro- and micronutrients. In addition, special conditions such as acute kidney injury and approaches to obesity treatment are reviewed.