Measurement of urinary cauxin in geriatric cats with variable plasma creatinine concentrations and proteinuria and evaluation of urine cauxin-to-creatinine concentration ratio as a predictor of developing azotemia.
OBJECTIVE
To evaluate urine cauxin immunoreactivity in geriatric cats with variable plasma creatinine concentrations and proteinuria and to assess urinary cauxin-to-creatinine concentration ratio (UC/C) as a predictor of developing azotemia.


METHODS
188 client-owned geriatric (>or= 9 years of age) cats.


METHODS
A direct immunoassay was developed and validated for the quantification of urinary cauxin relative to a standard curve generated from a urine sample with high cauxin immunoreactivity. Relationships among UC/C, plasma creatinine concentration, and proteinuria were assessed. Nonazotemic cats were recruited and followed for 12 months. Urinary cauxin-to-creatinine concentration ratio was evaluated as a predictor of development of azotemia in these cats.


RESULTS
No relationship was evident between UC/C and plasma creatinine concentration. A weak positive correlation was identified between UC/C and urine protein-to-creatinine concentration ratio (r = 0.212). At entry to the longitudinal study, those cats that later developed azotemia had a UC/C that was significantly higher than in those remaining nonazotemic after 12 months.


CONCLUSIONS
The UC/C did not vary with severity of azotemia but appeared contributory to the feline urinary proteome. High UC/C values were predictive of the geriatric cats in our study developing azotemia. However, it seems unlikely that UC/C will provide additional information about the measurement of urine protein-to-creatinine concentration ratio as a biomarker for the development of azotemia in cats.
Jepson
Rosanne E
RE
Department of Veterinary Clinical Science, Royal Veterinary College, North Mymms, Hatfield, Hertfordshire AL9 7TA, England. rjepson@rvc.ac.uk
Syme
Harriet M
HM
Markwell
Peter
P
Miyazaki
Masao
M
Yamashita
Tetsuro
T
Elliott
Jonathan
J
D000375:Aging / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D053099:Azotemia / Q000097:blood / Q000652:urine / Q000662:veterinary*; D043182:Carboxylesterase / Q000652:urine*; D002371:Cat Diseases / Q000097:blood / Q000652:urine*; D002415:Cats / Q000254:growth & development*; D003404:Creatinine / Q000097:blood; D005260:Female; D007676:Kidney Failure, Chronic / Q000097:blood / Q000652:urine / Q000662:veterinary; D008297:Male; D009919:Orchiectomy / Q000662:veterinary; D010052:Ovariectomy / Q000662:veterinary; D011237:Predictive Value of Tests; D011507:Proteinuria / Q000662:veterinary*; D012016:Reference Values; D015203:Reproducibility of Results
D003404:Creatinine; D043182:Carboxylesterase; C515680:cauxin protein, Felis catus