title: 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, L-carnitine, and medium-chain triglycerides.
abstract: The purpose of this study was to determine whether feeding cats reduced protein and phosphorus foods with added fish oil, L-carnitine, and medium-chain triglycerides (MCT) altered serum biomarkers of renal function. Thirty-two healthy cats, mean age 14.0 (8.3-19.6) years, were fed control food or one of two experimental foods for 6 months. All foods had similar concentrations of moisture, protein, and fat (approximately 8.0%, 26.5%, and 20.0%, respectively). Both experimental foods contained added fish oil (1.5%) and L-carnitine (500 mg/kg). Experimental-food 2 also contained increased MCT (10.5% from coconut oil), 1.5% added corn oil, and reduced animal fat. Glomerular filtration rate (GFR), serum biochemistries, renal function biomarkers including serum creatinine (sCr) and symmetrical dimethylarginine (SDMA), and plasma metabolomic profiles were measured at baseline, and at 1.5, 3, and 6 months. Body composition was determined by dual-energy X-ray absorptiometry. Although both experimental foods altered plasma fatty acids, carnitine and related metabolites, and lysophospholipid concentrations, there were no changes in renal function biomarkers. There was, however, a benefit in using SDMA versus sCr to assess renal function in older cats with less total lean mass. Compared with cats <12 years, those >15 years had lower total lean mass (P < 0.01), lower GFR (P = 0.04), and lower sCr concentrations (P < 0.01). However, SDMA concentrations (P < 0.01) were higher in older cats. This study shows that in cats, serum SDMA concentration is more highly correlated with GFR than sCr concentration, and, unlike sCr, which declines with age because of muscle wasting, SDMA increases as GFR declines with age.
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4802, USA. Electronic address: jean.hall@oregonstate.edu.
authors.forename: J A
authors.initials: JA
authors.lastname: Hall
authors.affiliation: IDEXX Laboratories, One IDEXX Drive, Westbrook, ME 04092, USA.
authors.forename: M
authors.initials: M
authors.lastname: Yerramilli
authors.affiliation: IDEXX Laboratories, One IDEXX Drive, Westbrook, ME 04092, USA.
authors.forename: E
authors.initials: E
authors.lastname: Obare
authors.affiliation: IDEXX Laboratories, One IDEXX Drive, Westbrook, ME 04092, USA.
authors.forename: M
authors.initials: M
authors.lastname: Yerramilli
authors.affiliation: Pet Nutrition Center, Hill's Pet Nutrition, Topeka, KS 66617-1587, USA.
authors.forename: S
authors.initials: S
authors.lastname: Yu
authors.affiliation: Pet Nutrition Center, Hill's Pet Nutrition, Topeka, KS 66617-1587, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Jewell
mesh_terms: D000367:Age Factors; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood; D015415:Biomarkers / Q000097:blood; D001774:Blood Chemical Analysis / Q000662:veterinary; D001798:Blood Proteins / Q000378:metabolism; D001823:Body Composition / Q000187:drug effects*; D015992:Body Mass Index; D002415:Cats; D003404:Creatinine / Q000097:blood*; D003430:Cross-Sectional Studies; D004032:Diet / Q000662:veterinary*; D018753:Diet, Protein-Restricted / Q000662:veterinary; D015525:Fatty Acids, Omega-3 / Q000097:blood / Q000378:metabolism*; D005260:Female; D005919:Glomerular Filtration Rate / Q000662:veterinary; D007677:Kidney Function Tests / Q000662:veterinary*; D008297:Male
chemical_list: D015415:Biomarkers; D001798:Blood Proteins; D015525:Fatty Acids, Omega-3; C024917:symmetric dimethylarginine; D001120:Arginine; D003404:Creatinine
keywords: Creatinine; Glomerular filtration rate; Healthy geriatric cats; Renal diets; SDMA