Chronic kidney disease is commonly seen in captive cheetahs as well as domestic cats. It is not completely understood why captive cheetahs are more prone to this condition than their wild counterparts, but diet, age, genetic diversity, and chronic stress have been proposed as risk factors. Scientists at the Smithsonian National Zoological Park (Washington DC), Cheetah Conservation Fund (Namibia) and White Oak Conservation, (Florida) partnered together to take a closer look at their captive cheetahs to identify methods that could be used to detect early kidney disease.
Kidney health is often assessed in animals by measuring the filtration rate of a vascular structure within the kidney called a glomerulus. When the glomerular filtration rate decreases, this is an indication that there is reduced kidney health. This filtration rate can be determined in animals using a substance called inulin and measuring its clearance by the glomeruli from the blood over time, but researchers were unsure if this method was applicable to cheetahs. Researchers were also curious to see if a recently identified compound in blood called symmetric dimethylarginine (SDMA) could be used to assess kidney function in cheetahs.
Thirty-three animals, with no evidence of impaired kidney function, had their blood samples evaluated for these parameters to determine their usefulness in identifying early renal disease and to establish normal reference ranges found in cheetahs. Researchers concluded that inulin clearance from the blood could be used to determine glomerular filtration rate. Importantly, it could therefore potentially be used to identify early kidney disease that is not detectable using
other methods such as serum BUN or creatinine. Serum SDMA concentration also was shown to hold promise as an indicator of decreased renal function and is worth investigating further.
While we work to identify why chronic kidney disease occurs with such a high prevalence in captive cheetahs, the validation of early detection methods plays a vital role in being able to provide early treatments and management of the disease. This study recently published in the American Journal of Veterinary Research (Glomerular filtration rate determined by measuring serum clearance of a single dose of inulin and serum symmetric dimethylarginine concentration in clinically normal cheetahs (Acinonyx jubatus). 2020 81(4): 375-380.), expands our understanding of kidney associated blood values and provides an exciting opportunity to help ensure captive cheetahs live long and healthy lives.
Contributing authors: Carlos R. Sanchez DVM, MSc1; Lee-Ann C. Hayek PhD3; Ellen P. Carlin DVM2,7, Scott A. Brown VMD, PhD4; Scott Citino DVM5, Laurie Marker PhD6 ; Krista L. Jones DVM, PhD2; and Suzan Murray DVM1,2. (1) Department of Animal Health and Global Health Program (2), Smithsonian National Zoological Park, Washington, DC; (3) Smithsonian Institution, Washington, DC; (4) Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia; (5) White Oak Conservation, Yulee, FL; (6) Cheetah Conservation Fund, Otjiwarongo, Namibia; (7) EcoHealth Alliance, New York, NY.