Effects of Infrared-A Irradiation on Skin: Discrepancies in Published Data Highlight the Need for an Exact Consideration of Physical and Photobiological Laws and Appropriate Experimental Settings (original) (raw)
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Alternative methodology for the study of infrared-A radiation effects on human skin
Surgical & Cosmetic Dermatology, 2016
Financial support: the study was sponsored by Grupo Kosmoscience Valinhos / Campinas (SP), Brazil Conflict of interest: none. Alternative methodology for the study of infrared-A radiation effects on human skin Metodologia alternativa para o estudo dos efeitos da radiação infravermelha-A sobre a pele humana
Infrared and skin: Friend or foe
Journal of photochemistry and photobiology. B, Biology, 2016
In the last decade, it has been proposed that the sun's IR-A wavelengths might be deleterious to human skin and that sunscreens, in addition to their desired effect to protect against UV-B and UV-A, should also protect against IR-A (and perhaps even visible light). Several studies showed that NIR may damage skin collagen content via an increase in MMP-1 activity in the same manner as is known for UVR. Unfortunately, the artificial NIR light sources used in such studies were not representative of the solar irradiance. Yet, little has been said about the other side of the coin. This article will focus on key information suggesting that IR-A may be more beneficial than deleterious when the skin is exposed to the appropriate irradiance/dose of IR-A radiation similar to daily sun exposure received by people in real life. IR-A might even precondition the skina process called photopreventionfrom an evolutionary standpoint since exposure to early morning IR-A wavelengths in sunlight may ready the skin for the coming mid-day deleterious UVR. Consequently IR-A appears to be the solution, not the problem. It does more good than bad for the skin. It is essentially a question of intensity and how we can learn from the sun.
Water-filtered infrared-A radiation (wIRA) is not implicated in cellular degeneration of human skin
German medical science : GMS e-journal, 2007
Excessive exposure to solar ultraviolet radiation is involved in the complex biologic process of cutaneous aging. Wavelengths in the ultraviolet-A and -B range (UV-A and UV-B) have been shown to be responsible for the induction of proteases, e. g. the collagenase matrix metalloproteinase 1 (MMP-1), which are related to cell aging. As devices emitting longer wavelengths are widely used in therapeutic and cosmetic interventions and as the induction of MMP-1 by water-filtered infrared-A (wIRA) had been discussed, it was of interest to assess effects of wIRA on the cellular and molecular level known to be possibly involved in cutaneous degeneration. Investigation of the biological implications of widely used water-filtered infrared-A (wIRA) radiators for clinical use on human skin fibroblasts assessed by MMP-1 gene expression (MMP-1 messenger ribonucleic acid (mRNA) expression). Human skin fibroblasts were irradiated with approximately 88% wIRA (780-1400 nm) and 12% red light (RL, 665-7...
Skin Pharmacology and Physiology, 2010
Solar radiation is well known to damage human skin, for example by causing premature skin ageing (i.e. photoageing). We have recently learned that this damage does not result from ultraviolet (UV) radiation alone, but also from longer wavelengths, in particular near-infrared radiation (IRA radiation, 760–1,440 nm). IRA radiation accounts for more than one third of the solar energy that reaches human skin. While infrared radiation of longer wavelengths (IRB and IRC) does not penetrate deeply into the skin, more than 65% of the shorter wavelength (IRA) reaches the dermis. IRA radiation has been demonstrated to alter the collagen equilibrium of the dermal extracellular matrix in at least two ways: (a) by leading to an increased expression of the collagen-degrading enzyme matrix metalloproteinase 1, and (b) by decreasing the de novo synthesis of the collagen itself. IRA radiation exposure therefore induces similar biological effects to UV radiation, but the underlying mechanisms are sub...
Minimal heating dose: a novel biological unit to measure infrared irradiation
Photodermatology, Photoimmunology and Photomedicine, 2006
Background and Objective: Infrared (IR) rays, which comprise approximately 40% of the solar radiation which reaches the earth's surface, have received relatively scant attention. As no standard method has yet been agreed upon for the biological evaluation of IR irradiation, the objective of this study is to suggest a new unit for IR irradiation. Methods: The skin temperature of 38 Korean volunteers was measured after IR irradiation with varying irradiance. Results: Skin temperature after IR irradiation at an irradiance of 2.02 W/cm 2 remained unchanged after 652 AE 22 s (mean AE standard error), which corresponds, in this case, to a total radiation dose of IR 1317.3 AE 44.84 J/cm 2. This quantity was designated as the minimal heating dose (MHD). We also demonstrated that MHD increased with increasing IR irradiance at lower IR irradiance (1.17 and 2.02 W/cm 2), whereas it became constant at higher irradiance (2.87 and 3.22 W/cm 2). No statistically significant correlations were detected between MHD and volunteers' ages, erythema index, or melanin index. Conclusion: We propose 'MHD' as a biological unit for the measurement of IR irradiation.
The Other End of the Rainbow: Infrared and Skin
Journal of Investigative Dermatology - J INVEST DERMATOL, 2010
Although infrared radiation (IRR) is ubiquitous in the terrestrial milieu, its effects on human skin have until now been largely ignored. Recent studies suggest an important role for infrared A (IRA) radiation (760-1440 nm) in dermal inflammation, photoaging, and photocarcinogenesis. In this issue, Calles et al. identify and analyze the IRA-induced transcriptome in human dermal fibroblasts. Their work paves the way for new research directions in IRA photobiology and raises important clinical questions regarding photoprotection and IRR-based dermatotherapy.
The impact of ultraviolet radiation on skin photoaging — review of in vitro studies
Journal of Cosmetic Dermatology, 2021
Skin aging involves internal and external processes. Changes occurring as a result of genetic conditions (internal, chronological aging) overlap with aging symptoms stimulated by environmental conditions (extrinsic aging). The most harmful external factor threatening the skin is ultraviolet (UV) radiation. UV radiation consists of three components: UVA (λ = 320−400 nm), UVB (λ = 280−320 nm) and UVC (λ = 100−280 nm). UVC radiation, unlike UVA and UVB radiation, is almost completely absorbed by the ozone layer. UVA and UVB rays reach the earth in sufficient quantities to damage skin structures. 1,2 Nevertheless, the negative impact has been also observed during skin exposure to infrared radiation (IR; λ = 760 nm−1 mm). 3 IR penetrates deeper layers of the skin than the rest of optical radiation. Even up to 17% of the incident infrared light can directly penetrate into the subcutaneous tissue. IR is absorbed by tissue chromophores (e.g., water) and converted into heat so that deep tissues can be heated. The heat is then transferred deeper by conduction, and pathological changes such as skin and corneal burns can occur. 4 The human skin, an important part of the innate immune system, has various molecular mechanisms that protect this organ from UV exposure. The first of these is the layered structure of the
A Study on the Effect of Sun Radiation on Human Health (The Skin
Elite Journal of Medical Sciences, 2024
A considerable high number of outdoor workers worldwide are constantly exposed for majority of their working life to sun radiation (SR); this exposure is known to induce various adverse health effects, mainly related to its ultraviolet (UV) component. The skin is one of the principal target organs for both acute and long-term exposure as well as other organs of the body. Ultraviolet B (UVB) rays vary with time and season and are the major cause of sunburns. Sunburned skin is a leading risk factor for melanoma and non-melanoma skin cancers, protection against exposure to UVB rays may be achieved by a combination of various approaches such as use of broad-spectrum sunscreen formulations. There was no significant association between age and color of skin (X 2 =36.929, P=0.005). Researchers recommend using sunscreen to protect the skin from harmful UVR. SR exposure is influenced by various environmental and individual factors, and occupation is one of the most relevant.