Epstein Murray, Lifschitz Meyer D
Division of Nephrology and Hypertension, University of Miami Miller School of Medicine, Miami, FL, USA.
Adult Nephrology Unit, Shaare Zedek Medical Center, Jerusalem, Israel.
Kidney Int Suppl (2011). 2016 Apr;6(1):7-15. doi: 10.1016/j.kisu.2016.01.006. Epub 2016 Mar 14.
Integrated mechanisms controlling the maintenance of potassium homeostasis are well established and are defined by the classic "feedback control" of potassium balance. Recently, increasing investigative attention has focused on novel physiological paradigms that increase the complexity and precision of homeostasis. This review briefly considers the classic and well-established feedback control of potassium and then considers subsequent investigations that inform on an intriguing and not widely recognized complementary paradigm: the "feed-forward control of potassium balance." Feed-forward control refers to a pathway in a homeostatic system that responds to a signal in the environment in a predetermined manner, without responding to how the system subsequently reacts (i.e., without responding to feedback). Studies in several animal species, and recently in humans, have confirmed the presence of a feed-forward control mechanism that is capable of mediating potassium excretion independent of changes in serum potassium concentration and aldosterone. Knowledge imparted by this update of potassium homeostasis hopefully will facilitate the clinical management of hyperkalemia in patients with chronic and recurrent hyperkalemia. Awareness of this updated integrative control mechanism for potassium homeostasis is more relevant today when the medical community is increasingly focused on leveraging and expanding established renin-angiotensin-aldosterone system inhibitor treatment regimens and on successfully coping with the challenges of managing hyperkalemia provoked by renin-angiotensin-aldosterone system inhibitors. These new insights are relevant to the future design of clinical trials delineating renal potassium handling.
控制钾稳态维持的综合机制已得到充分确立，并由经典的钾平衡“反馈控制”所定义。最近，越来越多的研究关注于新型生理模式，这些模式增加了稳态的复杂性和精确性。本综述简要回顾了经典且已确立的钾反馈控制，然后考虑了后续的研究，这些研究揭示了一种有趣但未被广泛认可的互补模式：“钾平衡的前馈控制”。前馈控制是指稳态系统中的一条通路，它以预定的方式对环境中的信号做出反应，而不响应系统随后的反应（即不响应反馈）。对几种动物物种以及最近对人类的研究已经证实，存在一种前馈控制机制，该机制能够独立于血清钾浓度和醛固酮的变化来调节钾排泄。钾稳态的这一更新所带来的知识有望促进慢性和复发性高钾血症患者高钾血症的临床管理。当医学界越来越关注利用和扩展已确立的肾素 - 血管紧张素 - 醛固酮系统抑制剂治疗方案，以及成功应对肾素 - 血管紧张素 - 醛固酮系统抑制剂引发的高钾血症管理挑战时，了解这种更新的钾稳态综合控制机制在当今更为重要。这些新见解与未来描述肾脏钾处理的临床试验设计相关。
