Figure 1.

Schematic of bilirubin generation and conjugation in the liver. The physiological properties of bilirubin may explain its ability to protect against the progression of DN. These properties make bilirubin a potential clinical biomarker or therapeutic target for a variety of disease states. BVR, biliverdin reductase; CAD, coronary artery disease; CO, carbon monoxide; CVD, cardiovascular disease; Fe²⁺, ferrous iron; Fe³⁺, ferric iron; NOS, nitric oxide synthase; RBC, erythrocyte; TNFα, tumor necrosis factor-α.