title: Long-term follow-up of renal function assessing serum cystatin C in dogs with diabetes mellitus or hyperadrenocorticism.
abstract: BACKGROUND
  Serum cystatin C (sCysC) is used as biomarker for glomerular filtration rate (GFR). The effects of diabetes mellitus (DM) on renal function in dogs are unclear. Some renal variables have been evaluated in dogs with hyperadrenocorticism (HAC), but not sCysC.
  
  
  OBJECTIVE
  The purpose of this study was the validation of a particle-enhanced nephelometric immunoassay (PENIA) for measuring canine sCysC, and to assess renal function in dogs with DM or HAC.
  
  
  METHODS
  A PENIA was analytically validated for canine sCysC by determining imprecision and linearity. In a longitudinal 6-month study, renal function of 14 DM dogs was assessed, using serum creatinine, GFR, urinary protein-to-creatinine (UPC) ratio, urinary markers, systolic blood pressure (SBP), and sCysC, and compared to 17 healthy dogs at baseline. Furthermore, sCysC was measured at initial presentation and during a 12-month follow-up in 22 HAC dogs.
  
  
  RESULTS
  The sCysC intra- and inter-assay variation coefficients were < 8% and highly linear (r = .997). About 33% and 67% of DM dogs had persistent proteinuria and systemic hypertension, respectively, but there were no significant differences in GFR, UPC, and urinary markers over time, and compared with healthy dogs at initial presentation. Serum CysC decreased significantly (P < .05) over time within the DM group. It did not change significantly over time within the HAC group.
  
  
  CONCLUSIONS
  A PENIA measured sCysC linearly and precisely. There were no clinically relevant renal alterations over time in dogs with DM, although persistent proteinuria was observed. In dogs with HAC, sCysC measurement was not useful, although significant GFR changes occurred over time.
authors.affiliation: Department of Small Animal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Sofie J J
authors.initials: SJ
authors.lastname: Marynissen
authors.affiliation: Department of Small Animal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Pascale M Y
authors.initials: PM
authors.lastname: Smets
authors.affiliation: Department of Small Animal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Liesbeth F E
authors.initials: LF
authors.lastname: Ghys
authors.affiliation: Department of Small Animal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Dominique
authors.initials: D
authors.lastname: Paepe
authors.affiliation: Department of Clinical Chemistry, Microbiology and Immunology, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Joris
authors.initials: J
authors.lastname: Delanghe
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Sara
authors.initials: S
authors.lastname: Galac
authors.affiliation: Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Meyer
authors.affiliation: Department of Clinical Sciences and Clinical Research Unit, INRA, École Nationale Vétérinaire de Toulouse (ENVT), Toulouse, France.
authors.forename: Hervé P
authors.initials: HP
authors.lastname: Lefebvre
authors.affiliation: Department of Small Animal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Daminet
mesh_terms: D000308:Adrenocortical Hyperfunction / Q000097:blood / Q000662:veterinary*; D000818:Animals; D055316:Cystatin C / Q000097:blood*; D003920:Diabetes Mellitus / Q000097:blood / Q000662:veterinary*; D004285:Dogs; D005500:Follow-Up Studies; D007668:Kidney / Q000378:metabolism*
chemical_list: D055316:Cystatin C
keywords: Biomarker; GFR; canine; kidney; proteinuria