Abstract 18804: Chronic Pressure Overload Impairs Cardiac Microvascular Endothelial Cell Metabolism and Angiogenic Potential in Aortic Stenosis Patients
Introduction: Chronic myocardial pressure overload leads to interstitial fibrosis and capillary rarefaction. We previously showed that transverse aortic constriction upregulates Transforming Growth Factor ß (TGFß)-dependent fibrosis-related genes, including Cartilage Intermediate Layer Protein (CILP), in murine cardiac microvascular endothelial cells (MiVEC).
Hypothesis: In aortic stenosis patients (AS), chronic pressure overload induces a phenotypic switch in cardiac MiVEC that impairs EC function and metabolism.
Methods: We culture-expanded CD31+ MiVEC after MACS isolation from right atrium (RA, low pressure) and left ventricular outflow tract (LVOT, pressure overload) surgical biopsies of AS and exposed them to TGFß and the TGFß-1 receptor inhibitor, SD208 for 48h. At p4, MiVEC angiogenic potential was determined using 2D tube formation and 3D spheroid sprouting. Glycolytic and oxidative metabolic fluxes were assessed using 3H-5-Glucose and 3H-9,10-palmitic acid.
Results: In AS, CILP expression in LVOT positively correlated with LA dilation and pulmonary artery pressure (n=19, Pearson, P<0.05). In cultured MiVEC (n=10), CILP expression trended to be higher in LVOT than RA (P=0.08) and increased >300-fold in the presence of TGF-ß (p=0.01) via activation of the SD208-inhibitable TGFß-1 receptor. LVOT MiVEC showed less sprouts/spheroid (12.84±2.01 vs 23.17±1.38 in RA MiVEC, P<0.05, n=4) and impaired network formation, defined by a greater number of extremities (43.71±4.98 vs 30.55±3.57/cm2, P=0.03), less nodes (188.07±53.15 vs 273.14±62.76/cm2, P=0.03) and reduced total network length (7.95±1.34 vs 10.39±1.21 mm/mm2, P=0.02) compared to RA (n=6). Glycolytic flux was comparable (P=0.38), but palmitic acid flux was higher in LVOT-derived MiVEC (7.46±2.3 vs 3.54±1.10 nmol/h/mg protein in RA MiVEC, P<0.05, n=10).
Conclusions: Chronic pressure overload induces a molecular and metabolic switch in human cardiac MiVEC, characterized by TGFß-dependent CILP-upregulation, loss of angiogenic potential in vitro and increased fatty acid oxidation. These data, for the first time, identify human cardiac MiVEC as a critical target to reverse fibrosis and capillary rarefaction in pressure overloaded hearts.
Author Disclosures: S. Trenson: None. A. Wibowo: None. H. Hermans: None. S. Schoors: None. P. de Zeeuw: None. M. Vanhaverbeke: None. S. Craps: None. H. Gillijns: None. E. Caluwé: None. J. Bartunek: None. P. Herijgers: None. M. Herregods: None. P. Carmeliet: None. A. Luttun: None. S. Janssens: None.
- © 2016 by American Heart Association, Inc.