JOURNAL SCAN
Article reprinted with the permission of DMV360, January 2015, Veterinary Medicine
is a copyrighted publication of Advanstar. Communications inc. All rights reserved.
SDMA Pinpointed as
Biomarker for Feline
Renal disease
References Summarised by
Jennifer L. Garcia, DVM, DACVIM
Does this form of testing hold the key to diagnosing
deterioration of the kidney in cats earlier?
Why they did it
Chronic kidney disease in cats is often not recognised
in the clinical setting until there is evidence of azotaemia and loss of urine concentrating ability. Identification of sensitive serum biomarkers, which would allow
early identification of cats with renal disease, would
facilitate early intervention and improve patient care.
Symmetric dimethylarginine (SDMA) has been found
to be an accurate surrogate for estimated glomerular filtration rate (GFR) in people and a more sensitive
biomarker of renal function. These studies sought to
evaluate the utility of this biomarker in the setting of
feline renal disease.
What they did
Three studies have evaluated the possible role of
SDMA as a biomarker for feline renal disease.
In the first article (“Comparison of serum concentrations of symmetric dimethylarginine and creatinine as
kidney function biomarkers in cats with chronic kidney
disease”), the authors retrospectively reviewed SDMA
and serum creatinine concentrations in 15 cats with
azotaemia for ≥ three months, four nonazotaemic
cats with a greater than 30% decrease in GFR from
normal, and two nonazotaemic cats with calcium oxalate kidney stones. Data from 21 healthy geriatric cats
were also evaluated. Over a six-month period prior to
enrollment, these cats had three normal GFR test results, three normal serum creatinine concentrations
and three urine specific gravity assessments > 1.040.
In the second article (“Comparison of serum concentrations of symmetric dimethylarginine and creatinine
as kidney function biomarkers in healthy geriatric cats
fed reduced protein foods enriched with fish oil, Lcarnitine, and medium-chain triglycerides”), the authors fed control food or one of two experimental diets supplemented with fatty acids to 32 healthy cats.
Cats were fed these diets for six months, and serum
chemistry profiles, including SDMA and serum creatinine concentrations, GFR, and metabolic profiles,
were performed at baseline and at 1.5, three and six
months.
In the third article (“Relationship between serum symmetric dimethylarginine concentration and glomeru-
lar filtration rate in cats”), the authors sought to determine whether SDMA concentrations would rise as
expected in cats with reduced GFR. GFR was measured by using iohexal clearance in 10 client-owned
cats. All cats were > 11 years of age, and both azotaemic and nonazotaemic cats were included.
What they found
In the first article, the authors found that both SDMA
and serum creatinine concentrations correlated well
to changes in GFR. However, SDMA was elevated
before the serum creatinine concentration in 81% of
cats (17 of the 21 subjects) by a mean of 17 months
(range, 1.5 to 48 months). SDMA was elevated in all
nonazotaemic cats with a subnormal GFR. The SDMA
and serum creatinine concentrations remained within
the reference range for all the healthy geriatric cats.
In the second article, the authors found that diets
supplemented with fatty acids did not result in a