TEK and pulmonary arterial hypertension: Although previous studies described the occurrence of pulmonary edema [37] and decreased pulmonary microcirculatory perfusion in vivo [38] in response to reduced Tie2 expression, this was all initiated by either sepsis [36] or pulmonary arterial hypertension [38], suggesting pulmonary edema only occurs in response to both reduced Tie2 expression and an additional inflammatory hit.