Fig. 1

Autophagy, metabolome, microbiome—the interplay of endogenous and exogenous substrates. Critical illness triggers autophagy, which is concomitantly depressed by exogenous substrates. Intermediary metabolites can be captured in a more sophisticated approach summarized in the metabolome. Further, microbiome-modulated metabolites may influence the metabolomic pool and vice versa be influenced by the degree of underlying critical illness per se and associated treatment, particularly the use of antimicrobial agents