Urine and plasma metanephrine concentrations in cats with chronic kidney disease: characterization and correlation...

The role of the autonomic nervous system in the pathophysiology of chronic kidney disease (CKD) in cats is currently unknown.

To describe urine and plasma metanephrines concentration in cats with CKD and their correlation with biomarkers of kidney function.

Fifty-nine cats were recruited and divided into 3 groups: cats with CKD (n = 28), healthy cats (HC) (n = 21), and cats with nonadrenal, non-kidney-related chronic illness (n = 10).

A cross-sectional study was performed in cats recruited from a veterinary teaching hospital. Metanephrine and normetanephrine concentrations were measured in urine (U-MN/NMN) and plasma (P-MN/NMN) by liquid chromatography tandem mass spectrometry. Data were correlated with biomarkers of kidney function measured in the same time-point sample.

The CKD group had significantly higher P-NMN (median, 14.20; min-max, 5.65-34.09 nmol/L) than the HC group (7.03; 5.19-13.03 nmol/L). P-MN concentrations correlated with the urinary protein-creatinine ratio (UPCR) (r = 0.528, P = .017). P-NMN correlated with symmetric dimethylarginine (SDMA) (r = 0.604, P = .006), serum creatinine (r = 0.488, P = .029) and UPCR (r = 0.445, P = .049). U-MN:urine creatinine concentration (UCreat) ratio correlated with UPCR (r = 0.683, P < .001) and urine specific gravity (r = -0.397), P < .001). U-NMN:UCreat ratio correlated with SDMA (r = 0.558, P = .007), serum phosphate (r = 0.561, P = .005) and UPCR (r = 0.494, P = .017).

There is evidence of sympathetic nervous system dysfunction in cats with CKD.