Interestingly, we previously demonstrated that an endothelial dysfunction (evaluated by A23187 concentration response-induced nitric oxide-dependent flow increase and reactive hyperemia) exists in coronary microcirculation in female but not in male ApoE KO + HFD mice, while sodium nitroprusside-induced increase in coronary flow is comparable between WT and ApoE KO + HFD groups in both sexes [20]. Here, APOE is linked to endothelial dysfunction.