Endotheilum-specific deficiency of polycystin-1 promotes hypertension and cardiovascular disorders, and impairs arterio-venous fistula maturation

Abstract

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent hereditary kidney disease and is generally due to mutations in PKD1 and PKD2, encoding polycystins 1 and 2. In ADPKD, hypertension and cardiovascular (CV) disorders are highly prevalent but their mechanisms are partially understood. The objective of this study was to determine whether hypertension and the CV disorders of ADPKD are a consequence of the endothelial deficiency in the polycystin complex, rather than to the kidney disease, as is currently believed. Since endothelial cells express the polycystin complex, where it plays a central role in the mechanotransduction of blood flow, we generated a murine model with inducible deletion of Pkd1 in endothelial cells (Cdh5-CreERT2; Pkd1fl/fl) to specifically determine the role of endothelial polycystin-1 in ADPKD. We analyzed the endothelial phenotype associated with Pkd1 deficiency, invasive and noninvasive blood pressure, vascular function on isolated vessels, and echocardiography. The impact on the development of a model of aorto-cava arterio-venous fistula and on the CV consequences of superimposed chronic kidney disease were analyzed to further establish the clinical relevance of our results. As expected, transgenic mice presented normal kidney structure and function. Endothelial deletion of Pkd1 induced endothelial dysfunction, as demonstrated by impaired flow-mediated dilatation of resistance arteries and impaired relaxation to acetylcholine, increased blood pressure and prevented the normal development of arterio-venous fistula. In experimental chronic kidney disease induced by subtotal nephrectomy, endothelial deletion of Pkd1 further aggravated endothelial dysfunction, vascular remodelling and heart hypertrophy ( Fig. 1 ). Altogether, this study provides the first in vivo demonstration that specific deletion of Pkd1 in endothelial cells promotes endothelial dysfunction and hypertension independently of kidney cysts and of impaired kidney function, impairs arterio-venous fistula development and potentiates the cardiovascular alterations associated with chronic kidney disease. It establishes the endothelium as a significant contributor to cardiovascular disease in ADPKD.