Total Defense + Repair: A Novel Concept in Solar Protection and Skin Rejuvenation
July 2015 | Volume 14 | Issue 7 | Supplement Individual Articles | 3 | Copyright © July 2015
David H. McDaniel MD FAAD,a Iltefat H. Hamzavi MD,b Joshua A. Zeichner MD,cSabrina G. Fabi MD FAAD FAACS,d Vivian W. Bucay MD,e Julie C. Harper MD,f Jody A. Comstock MD,g Elizabeth T. Makino BS CCRA MBA,h Rahul C. Mehta PhD,h and Virginia L. Vega PhDh
aMcDaniel Institute of Anti-Aging Research, Virginia Beach, VA
bDepartment of Dermatology, Henry Ford Hospital, Detroit, MI
cDepartment of Dermatology, Mount Sinai Hospital, New York, NY
dDepartment of Dermatology, San Diego, CA
eBucay Center for Dermatology and Aesthetics, San Antonio, TX
fDepartment of Dermatology, University of Alabama, Birmingham, AL
gSkin Spectrum, Tuczon, AZ
hResearch & Development, SkinMedica Inc., an Allergan Company, Irvine, CA
Abstract
For more than a century, solar radiation has been known to contribute significantly to the extrinsic aging of skin. Until recently, this was almost exclusively attributed to the photodamage caused by ultraviolet (UV) light. However, a growing body of evidence now indicates that both infrared (IR) and visible light may also contribute to extrinsic skin aging. Infrared radiation, comprised of IR-A, IR-B, and IR-C, accounts for 54.3% of the total solar radiation reaching the skin. Studies have shown that IR radiation is also responsible for skin aging. Thus, IR-A radiation regulates hundreds of genes in skin, with roles in extracellular matrix (ECM) homeostasis regulation, apoptosis, cell growth, and stress responses. IR-B and IR-C radiation are primarily responsible for the increase in skin temperature associated with solar exposure, and are implicated in heat-related skin destruction of collagen and elastin, which is characterized by an increase in the expression of matrix metalloproteinases (MMPs). The contribution of visible light to photoaging is less well understood; however, some preliminary indication associates visible light with the upregulation of MMPs’ expression, DNA damage, and keratinocyte proliferation. Interestingly, the common denominator that links skin damage to the different solar wavelengths is the enhanced production of reactive molecule species (RMS) and therewith increased oxidative stress. SkinMedica® Total Defense + Repair (TD+R; SkinMedica Inc., an Allergan company, Irvine, CA) is a “superscreen,” which combines broad spectrum UV protection with a unique blend of antioxidants (SOL-IR Advanced Antioxidant Complex™) that provide protection from IR radiation while promoting skin repair. Preclinical studies have indicated that TD+R SPF34 prevents the formation of UV-induced sunburn cells and cyclobutane pyrimidine dimers while preserving or improving the expression of ECM genes. In addition, it prevents IR-A-triggered fragmentation of elastin fibers and expression of MMP-1. Initial clinical studies indicate that TDR+R SPF34 reduces the increase in surface temperature seen with IR radiation. A significant improvement in the appearance of lines and wrinkles was reported as early as week 2 in patients using TDR+R SPF34. In summary, we observed that the unique blend of antioxidants present in TD+R acts in harmony with SPF active ingredients, expanding solar protection beyond UV radiation and counterbalancing the deleterious effects of free radicals on skin cells by promoting endogenous repair.
J Drugs Dermatol. 2015;14(suppl 7):s3-s11.
INTRODUCTION
The relationship between sun exposure and skin damage
has long been established. Reports from as early as the 19th century described photoaging, photodistributed dermatosis, and a high incidence of keratosis and skin cancer in individuals who spent significant time outdoors.1,2 The first study identifying a causal link between a specific wavelength of light and skin damage was published in 1922, suggesting that wavelengths
in the ultraviolet-B (UVB) range were primarily responsible
for sunburn.3 Despite this early interest, the field of photodermatology
did not develop significantly until the late 1960’s,
when Kligman’s landmark report was published differentiating extrinsic ageing (photoaging) from intrinsic aging.4 At this point, it was still believed that UVB was the wavelength responsible for skin damage, a concept that was not challenged until 1977 when Kumakiri et al identified ultrastructural changes in skin as a result of repeated exposure to ultraviolet-A (UVA) radiation.5
Studies conducted during the late 20th century focused on the deleterious
effects of UVA and UVB radiation on the skin, with little or no consideration of the effects caused by other wavelengths.
