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Proteomic analysis of urine from male dogs during early stages of tubulointerstitial injury in a canine model of progressive glomerular disease

Authors

  • Mary B. Nabity,

    1. Departments of 1Veterinary Pathobiology, 2Small Animal Clinical Sciences, and 3Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; and 4Department of Population Health and Pathobiology, North Carolina State University, Raleigh, NC, USA
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  • 1 George E. Lees,

    1. Departments of 1Veterinary Pathobiology, 2Small Animal Clinical Sciences, and 3Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; and 4Department of Population Health and Pathobiology, North Carolina State University, Raleigh, NC, USA
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  • 2 Lawrence J. Dangott,

    1. Departments of 1Veterinary Pathobiology, 2Small Animal Clinical Sciences, and 3Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; and 4Department of Population Health and Pathobiology, North Carolina State University, Raleigh, NC, USA
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  • 3 Rachel Cianciolo,

    1. Departments of 1Veterinary Pathobiology, 2Small Animal Clinical Sciences, and 3Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; and 4Department of Population Health and Pathobiology, North Carolina State University, Raleigh, NC, USA
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  • 4 Jan S. Suchodolski,

    1. Departments of 1Veterinary Pathobiology, 2Small Animal Clinical Sciences, and 3Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; and 4Department of Population Health and Pathobiology, North Carolina State University, Raleigh, NC, USA
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  • and 2 Jörg M. Steiner 2

    1. Departments of 1Veterinary Pathobiology, 2Small Animal Clinical Sciences, and 3Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; and 4Department of Population Health and Pathobiology, North Carolina State University, Raleigh, NC, USA
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Mary B. Nabity, Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, 4467 TAMU, College Station, TX 77843, USA
E-mail: mnabity@cvm.tamu.edu

Abstract

Background: Sensitive and specific noninvasive biomarkers for tubulointerstitial injury are lacking, and proteomic techniques provide a powerful tool for biomarker discovery.

Objective: The aim of this study was to identify novel urinary biomarkers of early tubulointerstitial injury in canine progressive renal disease using both 2-dimensional differential in-gel electrophoresis (2-D DIGE), which identifies individual proteins, and surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF), which generates protein peak profiles.

Methods: Urine was collected from 6 male dogs with X-linked hereditary nephropathy (XLHN) at 2 time points (TP): 1) the onset of overt proteinuria (urine protein:creatinine ratio>2) and 2) the onset of azotemia (creatinine ≥1.2 mg/dL); corresponding renal biopsies were analyzed from 3 of the dogs. Urine samples from the 6 dogs were subjected to analysis by 2-D DIGE and SELDI-TOF. Urinary retinol-binding protein (RBP) was evaluated in 25 male dogs with XLHN and normal control dogs by Western blot analysis.

Results: Clinical data and histologic evaluation revealed reduced renal function and increased tubulointerstitial fibrosis at TP 2. A number of urine proteins and protein peaks were differentially present at the 2 time points, with several known biomarkers of renal disease identified in addition to several promising new biomarkers. RBP was first detected in urine approximately 2 months before onset of azotemia (TP 2), but after onset of overt proteinuria, and amounts increased with progression of disease.

Conclusions: Proteomic techniques were successfully used to identify urinary biomarkers of renal disease in dogs with XLHN. Urinary RBP is a promising biomarker for early detection of tubulointerstitial damage and progression to end-stage renal disease.

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