We measured plasma levels of VEGF165b in the PH group (pulmonary artery hypertension [PAH], n = 26; chronic thromboembolic pulmonary hypertension [CTEPH], n = 13) and control group (n = 30). Circulating levels of VEGF165b were higher in PH group than controls (97.1 vs. 53.3 pg/ml, P < 0.01). The multiple regression analysis demonstrated that the independent factor to determine the plasma levels of VEGF165b was the presence of PH (P = 0.04). Next, we focused on differences in VEGF165b levels and classifications of PH. Plasma VEGF165b level was higher only in idiopathic PAH (n = 9) than in control (137.1 vs. 53.3 pg/ml, P < 0.01), but not in PH related to collagen disease (n = 7), congenital heart disease (n = 10) and CTEPH (n = 13).
We demonstrated associations between circulating levels of VEGF165b and classifications of PH. VEGF165b, anti-angiogenic isoform, might contribute to the pathophysiology in PH, especially in idiopathic PAH. The level of plasma VEGF165b might be a novel marker that reflects the pathological conditions in patients with PH.