The same sequence of vascular impairment serving as an indicator for long-term prognosis applies to the (early) postnatal life of preterm infants. According to the Brenner hypothesis, the decreased number of nephrons causes hyperfiltration, sodium loss with activation of the renin-angiotensinaldosterone system and hypertension [Brenner et al.], a process that entails further nephron loss, predisposition to develop proteinuria and possibly chronic kidney disease [Vieux et al., Puddu et al.].