Chronic kidney disease (CKD) is a common cause of morbidity and mortality in cats and dogs.  Serum concentrations of symmetric dimethylarginine (SDMA) have been shown to detect CKD in cats on average 17.0 months before serum creatinine (Cr) concentration increased above the reference interval, and in dogs on average 9.8 months before serum Cr concentrations increased above the reference interval.

  • SDMA is produced by post-translational methylation of arginine residues in proteins.   Subsequent degradation of proteins containing methylated arginines yields individual methylated arginine amino acids.
  • Free methylarginines are released into the cytosol following proteolysis, and then enter the blood circulation.
  • SDMA is excreted by glomerular filtration and accumulates in patients with renal failure.  We have shown that serum SDMA concentrations are correlated with glomerular filtration rate in dogs and cats.
  • Serum SDMA concentrations are not influenced by lean body mass as is serum Cr concentration. This limits serum Cr utility as a biomarker for monitoring renal function in dogs and cats with decreased lean body mass. 

Now that the utility of using serum SDMA as an early indicator of compromised renal function in pets with CKD has been demonstrated, we find ourselves in the fortunate situation of being able to evaluate benefits of early dietary interventions to improve the outcome of pets with CKD.

  • For example, dietary supplementation of mildly protein-restricted, energy-dense currently available renal protective food with functional lipids (fish oil), antioxidants (lipoic acid), carnitine, increasing concentrations of botanicals (fruits and vegetables), and more bioavailable protein sources reverses the age-associated decline in glomerular filtration rate in healthy geriatric dogs.
  • As a renal biomarker, SDMA was more sensitive for detecting diet-induced changes in glomerular filtration rate than serum Cr.
  • Feeding dogs with IRIS-Stage 1 CKD a renal food for 12 months resulted in improvement in renal biomarker concentrations, in particular decreases in serum SDMA concentration, and owners noted improvement in overall quality of life attributes.