Summary: | 碩士 === 國立中興大學 === 獸醫學系暨研究所 === 107 === Indoxyl sulfate (IS) is a renal marker for prediction of the progression of International Renal Interest Society staging 2 and 3 chronic kidney diseases (CKD) in both dogs and cats with the CKD. Symmetric dimethylarginine (SDMA) is strongly correlated with decrease in glomerular filtration rate and be used as an early renal biomarker than the conventionally used creatinine. Interest in their use in veterinary clinical practice is increasing, however, none has studied their inter-relationship and an analytical method for quantifying both markers is unavailable. In the present study, an HPLC-UV method to simultaneously quantify IS and SDMA in canine and feline plasma and urine is developed. The calibration functions were linear in the ranges of 0.042-84.84 mg/L for IS and 0.013-1.33 μg/L for SDMA, covering both the levels reached in healthy and CKD dogs and cats. The inter-day precisions were 3.8% for IS and 2.9% for SDMA. The results indicated that the HPLC-UV method is useful as a selective, rapid and sensitive analytical tool for simultaneous determination of IS and SDMA. Application in clinical cases revealed that plasma and urinary IS were useful (area under the ROC curve > 0.75) in detection of dog and cat CKD respectively, while urinary protein to IS ratio was with good sensitivity and specificity in both dogs and cats. However, in CKD dogs and cats, SDMA peak was partially superimposed with a peak of an unknown substance. A preliminary study using LC-MS/MS to differentiate plasma and urinary levels of SDMA and asymmetric dimethylarginine (ADMA) revealed that urinary SDMA and ADMA might be potential renal markers in veterinary medicine. In conclusion, an HPLC-UV method to simultaneously detect IS and SDMA in plasma/urine was validated; additionally, urinary IS, SDMA and ADMA are promising renal markers in dogs and cats.
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