ABSTRACT
OBJECTIVE: To describe serum fibroblast growth factor 23 (FGF-23) concentrations in young adult cats with remnant kidney model-induced chronic kidney disease (CKD) and to evaluate the effects of orally administered aluminum hydroxide (ALOH) on serum phosphate and FGF-23 concentrations in these cats. ANIMALS: 17 adult, purpose-bred cats with induced CKD and 13 healthy, age-matched cats. METHODS: A prospective, randomized study. Cats with induced CKD fed a wet renal diet received treatment with ALOH (90 mg/kg/d, PO) on days 0 to 42 and no treatment on days 43 to 84 (treatment group, n = 9) or no treatment on days 0 to 84 (control group, n = 8). Standard serum and urine biochemical analyses and several parameters reflective of calcium-phosphate balance, including serum parathyroid hormone and FGF-23 concentrations, were evaluated at baseline and various time points, including days 42 and 84. Age-matched, healthy, community-owned cats underwent similar evaluations at a single time point. Baseline data from CKD cats were compared to those of healthy cats. Longitudinal data from CKD cats were compared over time. RESULTS: Serum phosphate, total and ionized calcium, and FGF-23 concentrations were significantly higher in CKD cats at baseline relative to healthy cats (all P ≤ .009). Serum phosphate concentration did not change significantly over time in either CKD group; however, FGF-23 concentrations significantly increased over time in the control group (P < .02) but not the treatment group (P = .059). CLINICAL RELEVANCE: Aluminum hydroxide did not reduce serum phosphate or FGF-23 concentrations in this small study of cats with induced CKD chronically eating a phosphate-restricted diet.
ABSTRACT
OBJECTIVE: To report acute and chronic outcomes of cats with chronic kidney disease (CKD) induced by a remnant kidney model. ANIMALS: 32 purpose-bred cats (n = 15 female, n = 17 male). PROCEDURES: Cats underwent a 2-stage reduction in renal mass through partial arterial ligation of 1 kidney (day 28) and delayed contralateral nephrectomy (day 0), targeting an 11/12th functional nephrectomy. Acute (days -28 - 29) survival and renal function parameters were compared over time, and the latter were evaluated as predictors for acute mortality. Chronic (days 30 to >1,100) survival, renal function, and morphology were described. RESULTS: Acutely, renal function deteriorated in all cats (mean ± SD baseline and day 28 serum creatinine mean concentration, 1.13 ± 0.23 mg/dL and 3.03 ± 1.20 mg/dL, respectively; P < .001; and GFR, 3.22 mL/min/kg ± 0.12 and 1.21 mL/min/kg ± 0.08, respectively; P < .001). Seven (22%) cats were euthanized after because of clinical signs of uremia after contralateral nephrectomy. Prenephrectomy renal function tests were not significant indicators for survival during this acute phase. Twenty-five cats entered the chronic phase. Ten cats were euthanized at a median of 163 days from nephrectomy because of progressive renal dysfunction. Median survival times were significantly different when stratified by acute kidney injury grade at day 29. Cats in the chronic phase had clinical courses similar to cats with naturally occurring CKD, and most (13/15) were in CKD stage 2. CLINICAL RELEVANCE: The remnant kidney model is effective at reducing kidney function to an extent that mimics important characteristics of spontaneous CKD in cats.