Li Nannan, Ying Yi, Yang Baoxue
School of Basic Medical Sciences, Peking University, Beijing, China.
Adv Exp Med Biol. 2023;1398:281-287. doi: 10.1007/978-981-19-7415-1_19.
One of the most prevalent indications of water-electrolyte imbalance is edema. Aquaporins (AQPs) are a protein family that can function as water channels. Osmoregulation and body water homeostasis are dependent on the regulation of AQPs. Human kidneys contain nine AQPs, five of which have been demonstrated to have a role in body water balance: AQP1, AQP2, AQP3, AQP4, and AQP7. Water imbalance is connected with AQP dysfunction. Hyponatremia with elevated AQP levels can accompany edema, which can be caused by disorders with low effective circulating blood volume and systemic vasodilation, such as congestive heart failure (CHF), hepatic cirrhosis, or the syndrome of incorrect antidiuretic hormone secretion (SIADH). In CHF, upregulation of AQP2 expression and targeting is critical for water retention. AQP2 is also involved in aberrant water retention and the formation of ascites in cirrhosis of the liver. Furthermore, water retention and hyponatremia in SIADH are caused by increased expression of AQP2 in the collecting duct. Fluid restriction, demeclocycline, and vasopressin type-2 receptor antagonists are widely utilized to treat edema. The relationship between AQPs and edema is discussed in this chapter.
水电解质失衡最常见的指征之一是水肿。水通道蛋白（AQPs）是一类可作为水通道发挥作用的蛋白质家族。渗透调节和机体水平衡依赖于对水通道蛋白的调节。人类肾脏含有9种水通道蛋白，其中5种已被证明在机体水平衡中发挥作用：水通道蛋白1、水通道蛋白2、水通道蛋白3、水通道蛋白4和水通道蛋白7。水平衡失调与水通道蛋白功能障碍有关。水通道蛋白水平升高伴低钠血症可伴有水肿，这可能由有效循环血容量降低和全身血管舒张的疾病引起，如充血性心力衰竭（CHF）、肝硬化或抗利尿激素分泌不当综合征（SIADH）。在充血性心力衰竭中，水通道蛋白2表达上调和靶向作用对于水潴留至关重要。水通道蛋白2也参与了肝硬变时异常的水潴留和腹水形成。此外，抗利尿激素分泌不当综合征中的水潴留和低钠血症是由集合管中水通道蛋白2表达增加引起的。限制液体摄入、地美环素和血管加压素2型受体拮抗剂被广泛用于治疗水肿。本章将讨论水通道蛋白与水肿之间的关系。
