Evaluation of mass spectrometry of urinary proteins and peptides as biomarkers for cats at risk of developing azotemia.
OBJECTIVE
To evaluate proteomic delineation of feline urine by mass spectrometry as a method for identifying biomarkers in cats at risk of developing azotemia.


METHODS
Urine samples from geriatric cats (> 9 years old) with chronic kidney disease and nonazotemic cats that either remained nonazotemic (n = 10) or developed azotemia (10) within 1 year.


METHODS
Optimization studies with pooled urine were performed to facilitate the use of surface enhanced laser desorption-ionization time-of-flight mass spectrometry (SELDI-TOF-MS) for analysis of the urinary proteome of cats. Urine samples from nonazotemic cats at entry to the study were analyzed via SELDI-TOF-MS with weak cation exchange and strong anion exchange arrays. Spectral data were compared to identify biomarkers for development of azotemia.


RESULTS
Low protein concentration in feline urine precluded direct application to array surfaces, and a buffer exchange and concentration step was required prior to SELDI-TOF-MS analysis. Three preparation conditions by use of weak cation and strong anion exchange arrays were selected on the basis of optimization studies for detection of biomarkers. Eight potential biomarkers with an m/z of 2,822, 9,886, 10,033, 10,151, 10,234, 11,653, 4,421, and 9,505 were delineated.


CONCLUSIONS
SELDI-TOF-MS can be used to detect urinary low-molecular weight peptides and proteins that may represent biomarkers for early detection of renal damage. Further study is required to purify and identify potential biomarkers before their use in a clinical setting.
Department of Veterinary Clinical Sciences, Royal Veterinary College, NW1 0TU, London, England. rjepson@rvc.ac.uk
Rosanne E
RE
Jepson
Gary R
GR
Coulton
Matthew L
ML
Cowan
Peter
P
Markwell
Harriet M
HM
Syme
Jonathan
J
Elliott
D000818:Animals; D053099:Azotemia / Q000652:urine / Q000662:veterinary*; D015415:Biomarkers / Q000652:urine; D002371:Cat Diseases / Q000652:urine*; D002415:Cats; D057230:Limit of Detection; D010455:Peptides / Q000652:urine*; D040081:Protein Array Analysis / Q000379:methods* / Q000662:veterinary; D011507:Proteinuria / Q000652:urine / Q000662:veterinary*; D020543:Proteome / Q000032:analysis*; D012307:Risk Factors; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods* / Q000662:veterinary
D015415:Biomarkers; D010455:Peptides; D020543:Proteome