Prevention of infrared-A radiation mediated detrimental effects in human skin.

Photoaging and skin damage that is caused by solar radiation is well known. We have recently learned that within the solar spectrum this damage not only results from ultraviolet (UV) radiation, but also from longer wavelengths, in particular near infrared radiation. Accordingly, infrared radiation (IR) has been shown to alter the collagen equilibrium of the dermal extracellular matrix in at least 2 ways: (1) by leading to an increased expression of the collagen degrading enzyme matrixmetalloproteinase-1 while (2) decreasing the de novo synthesis of the collagen itself. Infrared-A (IRA) radiation exposure, therefore, induces similar biological effects to UV, but the underlying mechanisms are substantially different. IRA acts via the mitochondria and therefore protection from IR requires alternative strategies.