Glycation products and the pathogenesis of diabetic complications.

Glucose irreversibly modifies long-lived macromolecules by forming AGEs as a function of glucose concentration and time. AGEs cause qualitative and quantitative changes in extracellular matrix components such as type IV collagen, laminin, and vitronectin. These AGE-induced changes can affect cell adhesion, growth, and matrix accumulation. AGE-modified proteins also alter cell function by interacting with specific receptors on macrophages and endothelial cells, inducing changes that promote matrix overproduction, focal thrombosis, and vasoconstriction. DNA and nuclear proteins also may be targets for AGE damage. The persistence of accumulated AGEs during periods of normal glucose homeostasis may explain the phenomenon of hyperglycemic memory. Pharmacological inhibition of in vivo AGE formation by aminoguanidine prevents or ameliorates diabetic retinopathy, nephropathy, and neuropathy in animal models. These data suggest that aminoguanidine and other AGE inhibitors have a potential therapeutic role in the treatment of diabetic patients.