Reproduced with permission from Skibsted et al. Crit Care 2013; 17: 231 and adapted. Numbers denote targets within cellular processes for different systems biology approaches: 1, Genetic analysis and Single Nucleotide Polymorphisms (SNPs) and 2, epigenomics (methylation variable positions) 3, transcriptomics (mRNA); 4, proteomics; and 5, metabolomics; 6, pharmaco-(genomics/metabolomics/proteomics).