title: Characterization of kidney injury molecule-1 in cats.
abstract: BACKGROUND
  Kidney disease (KD) is common in older cats and presumed to arise from subclinical kidney injuries throughout life. Sensitive markers for detecting kidney injury are lacking. Kidney injury molecule 1 (KIM-1) is a useful biomarker of kidney injury in humans and rodents.
  
  
  OBJECTIVE
  Feline KIM-1 is conserved across species, expressed in kidney, and shed into urine of cats with acute kidney injury (AKI). The objectives were to characterize the feline KIM-1 gene and protein, assess available immunoassays for detecting KIM-1 in urine of cats, and identify KIM-1 expression in kidney sections.
  
  
  METHODS
  Samples from 36 hospitalized and 7 clinically healthy cats were evaluated. Hospitalized cats were divided into 2 groups based on absence (n = 20) or presence (n = 16) of historical KD.
  
  
  METHODS
  Feline KIM-1 genomic and complementary DNA sequences were amplified, sequenced and analyzed to determine the presence of isoforms, exon-intron organization and similarity with orthologous sequences. Presence in urine was evaluated by immunoassay and expression in kidney by immunohistochemistry.
  
  
  RESULTS
  Three expressed feline KIM-1 transcript variants comprising 894, 810, and 705 bp were identified in renal tissue. KIM-1 immunoassays yielded positive results in urine of cats with conditions associated with AKI, but not chronic KD. Immunohistochemistry of kidney sections identified KIM-1 in proximal tubular cells of cats with positive urine immunoassay results.
  
  
  CONCLUSIONS
  Kidney injury molecule 1 was expressed in specific segments of the nephron and detected in urine of cats at risk of AKI. Urine KIM-1 immunoassay may be a useful indicator of tubular injury.
authors.affiliation: Department of Pathobiology, University of Guelph, Guelph, ON.
authors.forename: S K
authors.initials: SK
authors.lastname: Bland
authors.forename: O
authors.initials: O
authors.lastname: Côté
authors.forename: M E
authors.initials: ME
authors.lastname: Clark
authors.forename: J
authors.initials: J
authors.lastname: DeLay
authors.forename: D
authors.initials: D
authors.lastname: Bienzle
mesh_terms: D058186:Acute Kidney Injury / Q000652:urine / Q000662:veterinary*; D000595:Amino Acid Sequence; D000818:Animals; D015415:Biomarkers / Q000652:urine; D002371:Cat Diseases / Q000652:urine*; D002415:Cats; D005260:Female; D007118:Immunoassay / Q000662:veterinary; D007668:Kidney / Q000737:chemistry; D007674:Kidney Diseases / Q000652:urine / Q000662:veterinary; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000652:urine*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011991:Receptors, Virus / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D015415:Biomarkers; D008562:Membrane Glycoproteins; D011991:Receptors, Virus
keywords: Feline; Renal disease; Serum creatinine; Urinalysis