Among the proteins differentially secreted by male and female ECs, we focused our interest on PTX3, for two main reasons: (i) a role for PTX3 has been proposed in the response to vascular damage and in the development and progression of atherosclerosis [34, 35], and (ii) we and others have previously shown that PTX3 is one of the more represented proteins in the secretome of human ECs, when cells are studied without sex segregation [21–23]. Here, PTX3 is linked to atherosclerosis.