Markers of respiratory morbidity, sepsis, and interestingly not hsPDA, which itself is associated with MR-proANP and CT-proET1, were no longer associated with the development of any stage ROP and ROP ≥ stage II after adjustment for co-factors.22 This suggests that ANP and ET1 might have an intrinsic effect on retinal vascularisation and ROP development but involved mechanisms are not fully understood. This evidence concerns the gene EDN1 and Sepsis.