Later studies using multiparametric photo-acoustic microscopy (measuring real-time changes in hemoglobin (Hb) concentration, oxygen saturation of Hb, and blood flow in peritubular capillaries in vivo) revealed that sepsis induced a significant reduction in peritubular capillary oxygen saturation of Hb and a decrease in kidney ATP levels, supporting the role of microcirculatory dysfunction in SA-AKI [19]. This evidence concerns the gene GSTM1 and acute kidney injury.