Carbamylated lipoproteins in diabetes

Figure 1 Carbamylation of lipoproteins is a non-enzymatic irreversible process mediated by isocyanate, and corresponds to the irreversible binding of a carbamoyl moiety to ε-NH₂ of lysine residues in proteins, resulting in carbamyllysine. Isocyanate originates from either the non-enzymatic spontaneous dissociation of urea, or from the myeloperoxidase (MPO)-mediated oxidation of thiocyanate, or to a lesser extent from tobacco smoke or atmospheric pollution. The urea pathway is of particular relevance in diabetic patients with chronic kidney disease. MPO level is elevated in patients with type 1 and type 2 diabetes (T2D). Plasma levels of carbamylated low-density lipoproteins and high-density lipoproteins are increased in T2D patients with or without chronic kidney disease. T2D: Type 2 diabete; CML: Carbamyllysine; MPO: Myeloperoxidase; Lys: Lysine; cLDL: Carbamylated low-density lipoproteins; cHDL: Carbamylated high-density lipoproteins.