Abstract
BACKGROUND: Chronic kidney disease (CKD) in cats is common and often leads to anemia. Hepcidin, an acute-phase protein and regulator of iron metabolism, is a potential biomarker for CKD-associated anemia. HYPOTHESIS/OBJECTIVES: To validate a hepcidin-25 ELISA for cats. To compare serum hepcidin concentrations in cats with CKD grouped by PCV, and explore associations between hepcidin and other clinicopathological variables. ANIMALS: One hundred client-owned cats with naturally occurring CKD. METHODS: Retrospective cross-sectional study. Cats with azotemic CKD were categorized by PCV: anemic (<28%), low-normal (LN-PCV, 28%-33%), or normal PCV (N-PCV, 35%-43%). LN-PCV and N-PCV groups were matched for plasma creatinine concentration, age, bodyweight, body and muscle condition scores. Associations between serum hepcidin concentrations, serum amyloid A (SAA), and clinicopathological variables were evaluated. Multiple regression analysis identified independent associations with hepcidin. RESULTS: The hepcidin-25 ELISA demonstrated acceptable precision, reproducibility, and specificity. Hepcidin was higher in anemic cats (median [range], 3.1 ng/mL [1.17-6.58]) compared to LN-PCV (2.21 ng/mL [1.24-6.94]) and N-PCV cats (2.29 ng/mL [1.41-7.72) (P = .007), with no difference between the latter two groups (P > .99). Hepcidin was weakly positively correlated with plasma creatinine (r = 0.265, P = .008) and plasma phosphate (r = 0.214, P = .034); no significant correlations were observed between hepcidin and PCV, SAA, or other clinicopathological variables. Plasma creatinine alone was associated with hepcidin in multivariable analysis, explaining <15% of the variance. CONCLUSIONS AND CLINICAL IMPORTANCE: Serum hepcidin concentration is higher in cats with CKD once anemia is established. Its association with plasma creatinine suggests kidney dysfunction influences its excretion, although additional factors not assessed in this study likely contribute.