These effects of angiopoietin-2 have been linked to IH in several models (26, 27), and protection against IH linked to antagonism by angiopoietin-1 (28), but our findings provide the first detailed understanding, on the molecular and cellular level, of how angiopoiein-2 regulates the development of IH by linking coagulation proteases with chemokine signaling. Here, ANGPT1 is linked to isolated hemihyperplasia.