Schematics of different pathways for glucose metabolism that lead to the activation of protein kinase C (PKC) and transforming growth factor β(TGF-β). In addition to undergoing glycolysis, excess glucose is channeled into the polyol and hexosamine pathways, which results in increased lipid synthesis and the generation of diacylglycerol (DAG). This leads to the activation of PKC and TGF-β and, consequently, increased extracellular matrix (ECM) synthesis. Abbreviation: GFAT, glutamine:fructose-6-phosphate-aminotransferase.