Acute‐Phase Proteins and Iron Status in Cats with Chronic Kidney Disease

Background The role of inflammation in the development and progression of chronic kidney disease (CKD) in cats is not well characterized. Hepcidin is a recently discovered acute‐phase protein (APP) that plays an important role in iron metabolism and contributes to the development of anemia in humans with CKD. Objectives To compare serum APP concentrations, iron status, and erythropoietin (EPO) concentrations in healthy cats and cats with naturally occurring CKD. Animals A total of 18 healthy control cats and 38 cats with CKD. Methods Prospective study. After complete physical examination and routine blood analysis, the following tests were performed: serum amyloid A (SAA), haptoglobin (HAP), EPO, serum iron and ferritin concentration as well as total iron‐binding capacity (TIBC). Serum hepcidin‐25 concentration was measured by ELISA kit designed for use in humans. Results Mean SAA and hepcidin concentrations were significantly higher and mean total iron and TIBC were significantly lower in the CKD group (P < .05). There was a significant positive correlation between serum creatinine concentration (CRT) and 2 of the APPs (SAA and hepcidin; P < .05). Increases in SAA and hepcidin were associated with decreases in TIBC and hematocrit in the CKD group. Fourteen (37%) of the cats with CKD were anemic, and these cats had significantly lower TIBC (P < .05), suggesting a functional iron deficiency. There was no association between survival time and APP, iron status, or EPO concentrations. Conclusions Our data suggest that CKD in cats is associated with systemic inflammation and altered iron metabolism. With further validation in cats, hepcidin assays may help better characterize these relationships.