Measures of high-density lipoprotein function in men and women with severe aortic stenosis

Background: Calcification of the aortic valve is a common heart valve disorder, in some cases leading to clinically impactful severe aortic stenosis (AS). Sex-specific differences in aortic valve calcification (ACV) exist, with women having a lower burden of calcification than men as measured by computed tomography; however, the pathophysiological mechanism that leads to these differences remains unclear. Methods: Using cultured human Tamm-Horsfall protein 1 (THP-1) macrophages and human aortic valve interstitial cells, the effects of high-density lipoprotein (HDL) particles isolated from the plasma of men and women with severe AS were studied for cholesterol efflux capacity (CEC). Results: HDL-CEC was assessed in 46 patients with severe AS, n = 30 men, n = 16 women. ATP-Binding Cassette A1 (ABCA1)-mediated HDL-CEC was measured from human cultured THP-1 macrophages to plasma HDL samples. Women with severe AS had more ABCA1-mediated HDL-CEC, as compared to men (8.50 ± 3.90% cpm vs. 6.80 ± 1.50% cpm, P = 0.04). HDL pre-β1 and α-particles were higher in woman than in men by spectral density, (pre-β1 HDL, 20298.29 ± 1076.15 vs. 15,661.74 ± 789.00, P = 0.002, and α-HDL, 63006.35 ± 756.81 vs. 50,447.00 ± 546.52, P = 0.03). Lecithin-cholesterol acyltransferase conversion of free cholesterol into cholesteryl esters was higher in women than men (16.44 ± 9.11%/h vs. 12.00 ± 8.07%/h, P = 0.03). Conclusions: Sex-specific changes in various parameters of HDL-CEC were found in patients with severe AS. Sex-based modifications in HDL functionality by HDL-CEC might account for the reduced burden of calcification in women vs. men with severe AS. Therefore, future studies should target sex-related pathways in AS to help to improve understanding and treatment of AS. Graphical abstract: Sex specifc differences in AVC and differences associated with HDL function in men and women with severe AS. When compared to men, women had higher preβ-HDL and α-HDL migrating particles, higher cholesterol efflux to HDL, and higher lecithin cholesterol acyl transferase (LCAT) activity, possibly indicating that improved reverse cholesterol transport may be protective against worsened calcification.[Figure not available: see fulltext.]