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Editor’s note: The regular Tech Edge columnist Mindy Goldstein, PhD, welcomes the following contribution from her Estée Lauder colleagues Daniel Maes, Lieve Declercq and Hugo Corstjens.
The Glycation Process
Glycation is the nonenzymatic reaction between sugars and proteins that leads to the reversible formation of intermediate products in the form of carbonyls such as methylglyoxal and glycolaldehyde. These intermediates are more reactive than the initial sugars and thereby propagate the reaction. During a period of a few months, the early glycation products react further to give rise slowly to inert and intramolecular cross-links called advanced glycation end products (AGE) or Maillard products.
Oxidative reactions appear to play a critical role in the extended chemical modification and cross-linking of proteins such as collagen by reactive sugars. Therefore the Maillard reaction products are often referred to as glycoxidation products. Throughout this paper the term glycation will be used to represent both processes.
The formation of the glycation end products affects mostly the body’s long-lived structural proteins such as collagen and elastin. This leads to a gradual stiffening and loss of tissue elasticity through a significant modification of the extracellular matrix. Further evolution of the glycation process is believed to contribute to the development of pathologies such as diabetes,2 neurodegenerative diseases3 and osteoarthritis.
The presence and detection of glycation products in the skin has been proposed by a number of groups as a marker and predictor for the progression of diabetic complications. The significant impact of the glycation process on the structure and functioning of the skin itself has only recently been explored.
This review and discussion will focus on the impact of the glycation process on skin aging only, and it will review the consequences in the healthy, nondiabetic population in order to maintain the relevance to the average user of cosmetic products.