Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo

Diglycolic acid (DGA) is present in trace amounts in our food supply and is classified as an indirect food additive linked with the primary GRAS food additive carboxymethyl cellulose (CMC). Carboxymethyl starches are used as a filler/binder excipient in dietary supplement tablets and a thickening in...

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Main Authors: Miriam E. Mossoba, Sanah Vohra, Howard Toomer, Shelia Pugh-Bishop, Zachary Keltner, Vanessa Topping, Thomas Black, Nicholas Olejnik, Ana Depina, Kathleen Belgrave, Jessica Sprando, Joyce Njorge, Thomas J. Flynn, Paddy L. Wiesenfeld, Robert L. Sprando
Format: Article
Language:English
Published: Elsevier 2017-01-01
Series:Toxicology Reports
Online Access:http://www.sciencedirect.com/science/article/pii/S2214750017300422
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author Miriam E. Mossoba
Sanah Vohra
Howard Toomer
Shelia Pugh-Bishop
Zachary Keltner
Vanessa Topping
Thomas Black
Nicholas Olejnik
Ana Depina
Kathleen Belgrave
Jessica Sprando
Joyce Njorge
Thomas J. Flynn
Paddy L. Wiesenfeld
Robert L. Sprando
spellingShingle Miriam E. Mossoba
Sanah Vohra
Howard Toomer
Shelia Pugh-Bishop
Zachary Keltner
Vanessa Topping
Thomas Black
Nicholas Olejnik
Ana Depina
Kathleen Belgrave
Jessica Sprando
Joyce Njorge
Thomas J. Flynn
Paddy L. Wiesenfeld
Robert L. Sprando
Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo
Toxicology Reports
author_facet Miriam E. Mossoba
Sanah Vohra
Howard Toomer
Shelia Pugh-Bishop
Zachary Keltner
Vanessa Topping
Thomas Black
Nicholas Olejnik
Ana Depina
Kathleen Belgrave
Jessica Sprando
Joyce Njorge
Thomas J. Flynn
Paddy L. Wiesenfeld
Robert L. Sprando
author_sort Miriam E. Mossoba
title Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo
title_short Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo
title_full Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo
title_fullStr Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo
title_full_unstemmed Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo
title_sort comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo
publisher Elsevier
series Toxicology Reports
issn 2214-7500
publishDate 2017-01-01
description Diglycolic acid (DGA) is present in trace amounts in our food supply and is classified as an indirect food additive linked with the primary GRAS food additive carboxymethyl cellulose (CMC). Carboxymethyl starches are used as a filler/binder excipient in dietary supplement tablets and a thickening ingredient in many other processed foods. We sought to utilize the human proximal tubule HK-2 cell line as an in vitro cellular model system to evaluate its acute nephrotoxicity of DGA. We found that DGA was indeed toxic to HK-2 cells in all in vitro assays in our study, including a highly sensitive Luminex assay that measures levels of an in vitro biomarker of kidney-specific toxicity, Kidney Injury Molecule 1 (KIM-1). Interestingly, in vitro KIM-1 levels also correlated with in vivo KIM-1 levels in urine collected from rats treated with DGA by daily oral gavage. The use of in vitro and in vivo models towards understanding the effectiveness of an established in vitro system to predict in vivo outcomes would be particularly useful in rapidly screening compounds that are suspected to be unsafe to consumers. The merit of the HK-2 cell model in predicting human toxicity and accelerating the process of food toxicant screening would be especially important for regulatory purposes. Overall, our study not only revealed the value of HK-2 in vitro cell model for nephrotoxicity evaluation, but also uncovered some of the mechanistic aspects of the human proximal tubule injury that DGA may cause. Keywords: Kidney proximal tubule, HK-2 cells, Diglycolic acid, Nephrotoxicity
url http://www.sciencedirect.com/science/article/pii/S2214750017300422
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spelling doaj-33362497970a424f9240161a3482ee432020-11-25T01:39:50ZengElsevierToxicology Reports2214-75002017-01-014342347Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivoMiriam E. Mossoba0Sanah Vohra1Howard Toomer2Shelia Pugh-Bishop3Zachary Keltner4Vanessa Topping5Thomas Black6Nicholas Olejnik7Ana Depina8Kathleen Belgrave9Jessica Sprando10Joyce Njorge11Thomas J. Flynn12Paddy L. Wiesenfeld13Robert L. Sprando14Corresponding author at: US FDA, MOD-1 Laboratories, 8301 Muirkirk Rd., HFS-025, Lab 1406, Laurel, MD 20708, United States.; U.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesU.S. Food and Drug Administration (US FDA), Center for Food Safety and Applied Nutrition (CFSAN), Office of Applied Research and Safety Assessment (OARSA), Division of Toxicology (DOT), 8301 Muirkirk Rd., Laurel, MD 20708, United StatesDiglycolic acid (DGA) is present in trace amounts in our food supply and is classified as an indirect food additive linked with the primary GRAS food additive carboxymethyl cellulose (CMC). Carboxymethyl starches are used as a filler/binder excipient in dietary supplement tablets and a thickening ingredient in many other processed foods. We sought to utilize the human proximal tubule HK-2 cell line as an in vitro cellular model system to evaluate its acute nephrotoxicity of DGA. We found that DGA was indeed toxic to HK-2 cells in all in vitro assays in our study, including a highly sensitive Luminex assay that measures levels of an in vitro biomarker of kidney-specific toxicity, Kidney Injury Molecule 1 (KIM-1). Interestingly, in vitro KIM-1 levels also correlated with in vivo KIM-1 levels in urine collected from rats treated with DGA by daily oral gavage. The use of in vitro and in vivo models towards understanding the effectiveness of an established in vitro system to predict in vivo outcomes would be particularly useful in rapidly screening compounds that are suspected to be unsafe to consumers. The merit of the HK-2 cell model in predicting human toxicity and accelerating the process of food toxicant screening would be especially important for regulatory purposes. Overall, our study not only revealed the value of HK-2 in vitro cell model for nephrotoxicity evaluation, but also uncovered some of the mechanistic aspects of the human proximal tubule injury that DGA may cause. Keywords: Kidney proximal tubule, HK-2 cells, Diglycolic acid, Nephrotoxicityhttp://www.sciencedirect.com/science/article/pii/S2214750017300422