Browsing by Subject "Nephrology"

Now showing 1 - 10 of 21
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    2016 Advances in Renal Imaging Symposium
    (Indiana University School of Medicine/IUPUI, 2016-11-15) IUPUI Imaging Research Symposium
    The primary objective of the “Advances in Renal Imaging” symposium is to provide a forum for nephrology researchers and imaging scientists to come together and discuss needed kidney imaging biomarkers and explore the development of imaging technologies designed to address specific renal imaging needs. The Symposium includes three sessions of oral presentations with invited speakers addressing the following general themes: 1) Need for advances in renal imaging and the identification of potential imaging biomarker targets; 2) Advances in renal microscopy methods for basic science renal research; 3) Advances in molecular, perfusion, and structural renal imaging.
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    The archaeal Dps nanocage targets kidney proximal tubules via glomerular filtration
    (American Society for Clinical Investigation, 2019-09-03) Uchida, Masaki; Maier, Bernhard; Waghwani, Hitesh Kumar; Selivanovitch, Ekaterina; Pay, S. Louise; Avera, John; Yun, EJun; Sandoval, Ruben M.; Molitoris, Bruce A.; Zollman, Amy; Douglas, Trevor; Hato, Takashi; Medicine, School of Medicine
    Nature exploits cage-like proteins for a variety of biological purposes, from molecular packaging and cargo delivery to catalysis. These cage-like proteins are of immense importance in nanomedicine due to their propensity to self-assemble from simple identical building blocks to highly ordered architecture and the design flexibility afforded by protein engineering. However, delivery of protein nanocages to the renal tubules remains a major challenge because of the glomerular filtration barrier, which effectively excludes conventional size nanocages. Here, we show that DNA-binding protein from starved cells (Dps) — the extremely small archaeal antioxidant nanocage — is able to cross the glomerular filtration barrier and is endocytosed by the renal proximal tubules. Using a model of endotoxemia, we present an example of the way in which proximal tubule–selective Dps nanocages can limit the degree of endotoxin-induced kidney injury. This was accomplished by amplifying the endogenous antioxidant property of Dps with addition of a dinuclear manganese cluster. Dps is the first-in-class protein cage nanoparticle that can be targeted to renal proximal tubules through glomerular filtration. In addition to its therapeutic potential, chemical and genetic engineering of Dps will offer a nanoplatform to advance our understanding of the physiology and pathophysiology of glomerular filtration and tubular endocytosis.
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    ASN Presidential Address 2013: innovation and individualization--the path forward for nephrology
    (American Society for Nephrology, 2014-05) Molitoris, Bruce A.; Department of Medicine, IU School of Medicine
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    ASN Presidential Address 2014: moving past nephrology's midlife crisis
    (American Society of Nephrology (ASN), 2015-04) Moe, Sharon M.; Department of Medicine, IU School of Medicine
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    Bacterial sepsis triggers an antiviral response that causes translation shutdown
    (American Society for Clinical Investigation, 2019-01-02) Hato, Takashi; Maier, Bernhard; Syed, Farooq; Myslinski, Jered; Zollman, Amy; Plotkin, Zoya; Eadon, Michael T.; Dagher, Pierre C.; Medicine, School of Medicine
    In response to viral pathogens, the host upregulates antiviral genes that suppress translation of viral mRNAs. However, induction of such antiviral responses may not be exclusive to viruses, as the pathways lie at the intersection of broad inflammatory networks that can also be induced by bacterial pathogens. Using a model of Gram-negative sepsis, we show that propagation of kidney damage initiated by a bacterial origin ultimately involves antiviral responses that result in host translation shutdown. We determined that activation of the eukaryotic translation initiation factor 2-α kinase 2/eukaryotic translation initiation factor 2α (Eif2ak2/Eif2α) axis is the key mediator of translation initiation block in late-phase sepsis. Reversal of this axis mitigated kidney injury. Furthermore, temporal profiling of the kidney translatome revealed that multiple genes involved in formation of the initiation complex were translationally altered during bacterial sepsis. Collectively, our findings imply that translation shutdown is indifferent to the specific initiating pathogen and is an important determinant of tissue injury in sepsis.
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    Calcium channel Orai1 promotes lymphocyte IL-17 expression and progressive kidney injury
    (American Society for Clinical Investigation, 2019-11-01) Mehrotra, Purvi; Sturek, Michael; Neyra, Javier A.; Basile, David P.; Anatomy and Cell Biology, School of Medicine
    We hypothesized that the store-operated calcium entry (SOCE) channel, Orai1, participates in the activation of Th17 cells and influences renal injury. In rats, following renal ischemia/reperfusion (I/R), there was a rapid and sustained influx of Orai1+ CD4 T cells and IL-17 expression was restricted to Orai1+ cells. When kidney CD4+ cells of post-acute kidney injury (post-AKI) rats were stimulated with angiotensin II and elevated Na+ (10-7 M/170 mM) in vitro, there was an enhanced response in intracellular Ca2+ and IL-17 expression, which was blocked by SOCE inhibitors 2APB, YM58483/BTP2, or AnCoA4. In vivo, YM58483/BTP2 (1 mg/kg) attenuated IL-17+ cell activation, inflammation, and severity of AKI following either I/R or intramuscular glycerol injection. Rats treated with high-salt diet (5-9 weeks after I/R) manifested progressive disease indicated by enhanced inflammation, fibrosis, and impaired renal function. These responses were significantly attenuated by YM58483/BTP2. In peripheral blood of critically ill patients, Orai1+ cells were significantly elevated by approximately 10-fold and Th17 cells were elevated by approximately 4-fold in AKI versus non-AKI patients. Further, in vitro stimulation of CD4+ cells from AKI patients increased IL-17, which was blocked by SOCE inhibitors. These data suggest that Orai1 SOCE is a potential therapeutic target in AKI and CKD progression.
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    Claudin-2 deficiency associates with hypercalciuria in mice and human kidney stone disease
    (American Society for Clinical Investigation, 2020-03-09) Curry, Joshua N.; Saurette, Matthew; Askari, Masomeh; Pei, Lei; Filla, Michael B.; Beggs, Megan R.; Rowe, Peter S. N.; Fields, Timothy; Sommer, Andre J.; Tanikawa, Chizu; Kamatani, Yoichiro; Evan, Andrew P.; Totonchi, Mehdi; Alexander, R. Todd; Matsuda, Koichi; Yu, Alan S. L.; Anatomy and Cell Biology, School of Medicine
    The major risk factor for kidney stone disease is idiopathic hypercalciuria. Recent evidence implicates a role for defective calcium reabsorption in the renal proximal tubule. We hypothesized that claudin-2, a paracellular cation channel protein, mediates proximal tubule calcium reabsorption. We found that claudin-2–null mice have hypercalciuria due to a primary defect in renal tubule calcium transport and papillary nephrocalcinosis that resembles the intratubular plugs in kidney stone formers. Our findings suggest that a proximal tubule defect in calcium reabsorption predisposes to papillary calcification, providing support for the vas washdown hypothesis. Claudin-2–null mice were also found to have increased net intestinal calcium absorption, but reduced paracellular calcium permeability in the colon, suggesting that this was due to reduced intestinal calcium secretion. Common genetic variants in the claudin-2 gene were associated with decreased tissue expression of claudin-2 and increased risk of kidney stones in 2 large population-based studies. Finally, we describe a family in which males with a rare missense variant in claudin-2 have marked hypercalciuria and kidney stone disease. Our findings indicate that claudin-2 is a key regulator of calcium excretion and a potential target for therapies to prevent kidney stones.
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    Conditional Myh9 and Myh10 inactivation in adult mouse renal epithelium results in progressive kidney disease
    (American Society for Clinical Investigation, 2020-11-05) Otterpohl, Karla L.; Busselman, Brook W.; Ratnayake, Ishara; Hart, Ryan G.; Hart, Kimberly R.; Evans, Claire M.; Phillips, Carrie L.; Beach, Jordan R.; Ahrenkiel, Phil; Molitoris, Bruce A.; Surendran, Kameswaran; Chandrasekar, Indra; Pathology and Laboratory Medicine, School of Medicine
    Actin-associated nonmuscle myosin II (NM2) motor proteins play critical roles in a myriad of cellular functions, including endocytosis and organelle transport pathways. Cell type–specific expression and unique subcellular localization of the NM2 proteins, encoded by the Myh9 and Myh10 genes, in the mouse kidney tubules led us to hypothesize that these proteins have specialized functional roles within the renal epithelium. Inducible conditional knockout (cKO) of Myh9 and Myh10 in the renal tubules of adult mice resulted in progressive kidney disease. Prior to overt renal tubular injury, we observed intracellular accumulation of the glycosylphosphatidylinositol-anchored protein uromodulin (UMOD) and gradual loss of Na+ K+ 2Cl– cotransporter from the apical membrane of the thick ascending limb epithelia. The UMOD accumulation coincided with expansion of endoplasmic reticulum (ER) tubules and activation of ER stress and unfolded protein response pathways in Myh9&10-cKO kidneys. We conclude that NM2 proteins are required for localization and transport of UMOD and loss of function results in accumulation of UMOD and ER stress–mediated progressive renal tubulointerstitial disease. These observations establish cell type–specific role(s) for NM2 proteins in regulation of specialized renal epithelial transport pathways and reveal the possibility that human kidney disease associated with MYH9 mutations could be of renal epithelial origin.
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    Consensus-Based Recommendations on Priority Activities to Address Acute Kidney Injury in Children: A Modified Delphi Consensus Statement
    (American Medical Association, 2022-09-01) Goldstein, Stuart L.; Akcan-Arikan, Ayse; Alobaidi, Rashid; Askenazi, David J.; Bagshaw, Sean M.; Barhight, Matthew; Barreto, Erin; Bayrakci, Benan; Bignall, Orville N. R.; Bjornstad, Erica; Brophy, Patrick D.; Chanchlani, Rahul; Charlton, Jennifer R.; Conroy, Andrea L.; Deep, Akash; Devarajan, Prasad; Dolan, Kristin; Fuhrman, Dana Y.; Gist, Katja M.; Gorga, Stephen M.; Greenberg, Jason H.; Hasson, Denise; Heydari Ulrich, Emma; Iyengar, Arpana; Jetton, Jennifer G.; Krawczeski, Catherine; Meigs, Leslie; Menon, Shina; Morgan, Jolyn; Morgan, Catherine J.; Mottes, Theresa; Neumayr, Tara M.; Ricci, Zaccaria; Selewski, David; Soranno, Danielle E.; Starr, Michelle; Stanski, Natalja L.; Sutherland, Scott M.; Symons, Jordan; Tavares, Marcelo S.; Wong Vega, Molly; Zappitelli, Michael; Ronco, Claudio; Mehta, Ravindra L.; Kellum, John; Ostermann, Marlies; Basu, Rajit K.; Pediatric ADQI Collaborative; Pediatrics, School of Medicine
    Importance: Increasing evidence indicates that acute kidney injury (AKI) occurs frequently in children and young adults and is associated with poor short-term and long-term outcomes. Guidance is required to focus efforts related to expansion of pediatric AKI knowledge. Objective: To develop expert-driven pediatric specific recommendations on needed AKI research, education, practice, and advocacy. Evidence review: At the 26th Acute Disease Quality Initiative meeting conducted in November 2021 by 47 multiprofessional international experts in general pediatrics, nephrology, and critical care, the panel focused on 6 areas: (1) epidemiology; (2) diagnostics; (3) fluid overload; (4) kidney support therapies; (5) biology, pharmacology, and nutrition; and (6) education and advocacy. An objective scientific review and distillation of literature through September 2021 was performed of (1) epidemiology, (2) risk assessment and diagnosis, (3) fluid assessment, (4) kidney support and extracorporeal therapies, (5) pathobiology, nutrition, and pharmacology, and (6) education and advocacy. Using an established modified Delphi process based on existing data, workgroups derived consensus statements with recommendations. Findings: The meeting developed 12 consensus statements and 29 research recommendations. Principal suggestions were to address gaps of knowledge by including data from varying socioeconomic groups, broadening definition of AKI phenotypes, adjudicating fluid balance by disease severity, integrating biopathology of child growth and development, and partnering with families and communities in AKI advocacy. Conclusions and relevance: Existing evidence across observational study supports further efforts to increase knowledge related to AKI in childhood. Significant gaps of knowledge may be addressed by focused efforts.
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    Documentation of acute kidney injury at discharge from the neonatal intensive care unit and role of nephrology consultation
    (Springer Nature, 2022) Chmielewski, Jennifer; Chaudhry, Paulomi M.; Harer, Matthew W.; Menon, Shina; South, Andrew M.; Chappell, Ashley; Griffin, Russell; Askenazi, David; Jetton, Jennifer; Starr, Michelle C.; Neonatal Kidney Collaborative; Pediatrics, School of Medicine
    Objective: To investigate whether NICU discharge summaries documented neonatal AKI and estimate if nephrology consultation mediated this association. Study design: Secondary analysis of AWAKEN multicenter retrospective cohort. Exposures: AKI severity and diagnostic criteria. Outcome: AKI documentation on NICU discharge summaries using multivariable logistic regression to estimate associations and test for causal mediation. Results: Among 605 neonates with AKI, 13% had documented AKI. Those with documented AKI were more likely to have severe AKI (70.5% vs. 51%, p < 0.001) and SCr-only AKI (76.9% vs. 50.1%, p = 0.04). Nephrology consultation mediated 78.0% (95% CL 46.5-109.4%) of the total effect of AKI severity and 82.8% (95% CL 70.3-95.3%) of the total effect of AKI diagnostic criteria on documentation. Conclusion: We report a low prevalence of AKI documentation at NICU discharge. AKI severity and SCr-only AKI increased odds of AKI documentation. Nephrology consultation mediated the associations of AKI severity and diagnostic criteria with documentation.