摘要：Abstract Hyperkalemia is frequently observed in patients at the end-stage of chronic kidney disease (CKD), and has possible harmful consequences on cardiac function. Many strategies are currently used to manage hyperkalemia, one consisting of increasing fecal K excretion through the administration of cation-exchange resins. In this study, we explored another more specific method of increasing intestinal K secretion by inhibiting the H,K-ATPase type 2 (HKA2), which is the main colonic K reabsorptive pathway. We hypothetised that the absence of this pump could impede the increase of plasma K levels following nephronic reduction (N5/6) by favoring fecal K secretion. In N5/6 WT and HKA2KO mice under normal K intake, the plasma K level remained within the normal range, however, a load of K induced strong hyperkalemia in N5/6 WT mice (9.1 ± 0.5 mM), which was significantly less pronounced in N5/6 HKA2KO mice (7.9 ± 0.4 mM, p < 0.01). This was correlated to a higher capacity of HKA2KO mice to excrete K in their feces. The absence of HKA2 also increased fecal Na excretion by inhibiting its colonic ENaC-dependent absorption. We also showed that angiotensin-converting-enzyme inhibitor like enalapril, used to treat hypertension during CKD, induced a less severe hyperkalemia in N5/6 HKA2KO than in N5/6 WT mice. This study therefore provides the proof of concept that the targeted inhibition of HKA2 could be a specific therapeutic maneuver to reduce plasma K levels in CKD patients.
