BackgroundSerum selenium concentrations and the activity of plasma glutathione peroxidase (GPx) decrease with the progression of chronic kidney disease (CKD) in human patients. Selenium is considered a limiting factor for plasma GPx synthesis. Plasma total antioxidant capacity (TAC) is decreased in CKD cats in comparison to healthy cats.HypothesisSerum selenium concentrations and plasma and erythrocyte GPx activity in cats with CKD are lower than in healthy cats. Serum selenium concentrations, the activity of enzymes, and plasma TAC progressively decrease with the progression of kidney disease according to IRIS (International Renal Interest Society) classification.AnimalsTwenty‐six client‐owned cats in IRIS stages I–IV of CKD were compared with 19 client‐owned healthy cats.MethodsA CBC, serum biochemical profile, urinalysis, plasma and erythrocyte GPx activity, serum selenium concentration, and plasma TAC were measured in each cat.ResultsCats in IRIS stage IV CKD had a significantly higher (P = .025) activity of plasma GPx (23.44 ± 6.28 U/mL) than cats in the control group (17.51 ± 3.75 U/mL). There were no significant differences in erythrocyte GPx, serum selenium concentration, and plasma TAC, either among IRIS stages I–IV CKD cats or between CKD cats and healthy cats.Conclusions and Clinical ImportanceErythrocyte GPx activity, serum selenium concentration, and plasma TAC do not change in CKD cats compared with healthy cats. Selenium is not a limiting factor in feline CKD. Increased plasma GPx activity in cats with stage IV CKD suggests induction of antioxidant defense mechanisms. Antioxidant defense systems might not be exhausted in CKD in cats.

The aim of the study was to investigate the effect of a therapeutic renal diet on selected clinical, biochemical, and urinary parameters and on selected parameters of oxidative stress in cats with early stages of chronic kidney disease (CKD). A prospective study of a 3-month duration was conducted to evaluate the effect of renal diet on selected clinical and laboratory parameters in client-owned cats with early stages of CKD. Of a total of 29 enrolled client-owned cats, nineteen (19) cats completed the study, ten receiving renal diet and nine receiving a diet of the owner's choice. A clinical examination was performed, and blood and urine samples were collected on the day of presentation and at regular check-ups after 3-4, 7-8, and 10-12 weeks. Serum creatinine and symmetric dimethylarginine (SDMA) concentrations and selected parameters of oxidative stress (plasma glutathione peroxidase (GPX) activity and plasma malondialdehyde (MDA) and serum selenium concentrations), were measured and electrophoresis of urinary proteins was performed. At inclusion, a significant positive correlation (p < 0.001) was found between serum selenium concentration and plasma GPX activity (Pearson correlation coefficient 0.83 (95% CI: [0.65 - 0.92]) and a significant negative correlation (p < 0.001) between serum SDMA and urine specific gravity (Pearson correlation coefficient -0.70 (95% CI: [-0.87 - (-0.38)]). At the end of the 3-month feeding trial no significant difference was found in SDMA and creatinine concentrations.

The portal venous system is a network of vessels that carry blood from the capillary beds of the major abdominal organs to the liver. During embryology, the portal venous system can develop aberrantly, leading to vascular connections between the portal and systemic venous circulation known as portosystemic shunts. The purpose of this comparative review with a few short representative case reports was to present the similarities and differences in portosystemic shunts in humans and small animals and their radiologic evaluation. Aberrant vascular connections between the portal and systemic venous circulation enable portal blood to bypass metabolism and detoxification in the liver, leading to significant clinical implications. Portosystemic shunts are very rare in humans, but these connections are much more common in small animals, affecting up to 0.6% of small animals. Portosystemic shunts can be congenital or acquired and are divided into intrahepatic and extrahepatic types. Because of its ability to accurately assess abdominal structures, large vessels, and their flow dynamics without anesthesia, ultrasonography has become the first imaging modality employed for the diagnostic evaluation of portosystemic shunts in both humans and small animals. This is usually followed by contrast-enhanced computed tomographic angiography in order to better define the exact shunt anatomy and to plan treatment. It is important to understand the embryology, anatomy, pathology, and pathophysiology of portosystemic shunts in order to understand the findings of radiologic imaging and to initiate appropriate treatment.