In contrast, the protein expression of eNOS, SOCS3 and SIRT1 was decreased in HUVECs treated with sera from HD patients compared to sera from healthy controls (eNOS: 0.56 ± 0.28 vs. 4.35 ± 1.77, respectively, p < 0.01; SOCS3: 0.67 ± 0.08 vs. 0.89 ± 0.41, respectively, p = 0.22; and SIRT1: 0.53 ± 0.48 vs. 0.82 ± 0.2, p = 0.07; Figure 2B). Here, SOCS3 is linked to Huntington disease.