The importance of ACE/Ang II signaling in human disease is suggested by increased levels of ACE and Ang II in patients with ARDS and patients with sepsis [16–19], and it is further underlined by genetic studies of an insertion/deletion (I/D) polymorphism within the ACE gene, with the D allele conferring higher ACE and Ang II levels in tissue and serum [20]. This evidence concerns the gene ACE and Sepsis.