Background: Chronic kidney disease (CKD) and hypertension have been associated with decreased bioavailability of nitric oxide (NO) and endothelial dysfunction. Increased concentrations of the endothelial nitric oxide synthase (eNOS) inhibitor asymmetric dimethylarginine (ADMA) are implicated.
Hypothesis: Plasma ADMA concentration is increased in cats with CKD and systemic hypertension corresponding to a decrease in total plasma nitrate/nitrite (NOx) availability. Decrease in systolic blood pressure (SBP) and proteinuria during treatment of hypertension with amlodipine besylate may be associated with increased NOx availability.
Animals: Sixty-nine client-owned normotensive and hypertensive cats with variable azotemia.
Methods: Plasma ADMA, symmetric dimethylarginine (SDMA), and l-arginine were measured simultaneously by hydrophilic-interaction liquid chromatography-electrospray tandem mass spectrometry in cats from 6 groups: normotensive nonazotemic (n = 10), normotensive mildly azotemic (n = 10), hypertensive mildly azotemic with hypertensive retinopathy (n = 20), hypertensive mildly azotemic without hypertensive retinopathy (n = 10), normotensive moderately azotemic cats (n = 10), and hypertensive nonazotemic cats (n = 9). Plasma NOx concentrations were measured.
Results: A moderate correlation between plasma creatinine and ADMA (n = 69, r= .608, P < .001), SDMA (n = 69, r= .741, P < .001), and NOx concentrations (n = 69, r= .589, P < .001) was observed. There was no association among plasma ADMA, SDMA, and NOx concentrations and SBP.
Conclusions and clinical importance: Plasma ADMA and SDMA concentrations are increased in cats with CKD and correlate with plasma creatinine concentration. This may imply the presence of endothelial dysfunction in cats with CKD. Plasma ADMA concentrations were not associated with systemic hypertension. Treatment of systemic hypertension with amlodipine besylate did not affect plasma ADMA or NOx concentrations.