Quantitative assessment of urea generation and elimination in healthy dogs and in dogs with chronic kidney disease

BACKGROUND: Kinetic assessment of urea, the main end product of protein metabolism, could serve to assess protein catabolism in dogs with chronic kidney disease (CKD). Protein malnutrition and catabolism are poorly documented in CKD and they often are neglected clinically because of a lack of appropriate evaluation tools. HYPOTHESIS: Generation and excretion of urea are altered in dogs with CKD. ANIMALS: Nine dogs with spontaneous CKD (IRIS stages 2-4) and 5 healthy research dogs. METHODS: Endogenous renal clearance (Clrenal) of urea and creatinine was measured first. Exogenous plasma clearance (Clplasma, total body clearance) of the 2 markers then was determined by an IV infusion of urea (250-1,000 mg/kg over 20 minutes) and an IV bolus of creatinine (40 mg/kg). Extrarenal clearance (Clextra) was defined as the difference between Clplasma)and Clrenal. Endogenous urea generation was computed assuming steady-state conditions. RESULTS: Median Clrenal and Clextra of urea were 2.17 and 0.21 mL/min/kg in healthy dogs and 0.37 and 0.28 mL/min/kg in CKD dogs. The proportion of urea cleared by extrarenal route was markedly higher in dogs with glomerular filtration rate<1 mL/kg/min than in normal dogs, reaching up to 85% of the total clearance. A comparable pattern was observed for creatinine excretion, except in 1 dog, Clextra remained<20% of Clplasma. CONCLUSION: Extrarenal pathways of urea excretion are predominant in dogs with advanced CKD and justify exploring adjunctive therapies based on enteric nitrogen excretion in dogs. A trend toward increased urea generation may indicate increased catabolism in advanced CKD.

Safety and efficacy of imatinib in CML over a period of 10 years: data from the randomized CML-study IV.

Tyrosine kinase inhibitors (TKI) have changed the natural course of chronic myeloid leukemia (CML). With the advent of second-generation TKI safety and efficacy issues have gained interest. The randomized CML - Study IV was used for a long-term evaluation of imatinib (IM). 1503 patients have received IM, 1379 IM monotherapy. After a median observation of 7.1 years, 965 patients (64%) still received IM. At 10 years, progression-free survival was 82%, overall survival 84%, 59% achieved MR(5), 72% MR(4.5), 81% MR(4), 89% major molecular remission and 92% MR(2) (molecular equivalent to complete cytogenetic remission). All response levels were reached faster with IM800 mg except MR(5). Eight-year probabilities of adverse drug reactions (ADR) were 76%, of grades 3-4 22%, of non-hematologic 73%, and of hematologic 28%. More ADR were observed with IM800 mg and IM400 mg plus interferon α (IFN). Most patients had their first ADR early with decreasing frequency later on. No new late toxicity was observed. ADR to IM are frequent, but mostly mild and manageable, also with IM 800 mg and IM 400 mg+IFN. The deep molecular response rates indicate that most patients are candidates for IM discontinuation. After 10 years, IM continues to be an excellent initial choice for most patients with CML.Leukemia advance online publication, 13 March 2015; doi:10.1038/leu.2015.36.