Aquaporins in Edema

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.