Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Sun’s infrared-A is not detrimental to the skin

15.07.2010
Recent scientific publications refute concerns regarding the infrared-A (IRA) component of the Sun’s radiation. Specific protection against the Sun’s infrared-A is therefore unnecessary. As far as ultraviolet in Sun's radiation is concerned, an adequate protection is still required.

Two new publications from the Berlin Charité and the University Medical Centre Mainz [1] and from the University of Stuttgart-Hohenheim [2] confirm earlier studies concerning the harmlessness of infrared-A [3] and its usefulness to humans. They refute concerns regarding possible detrimental effects of infrared-A, which is the main part of the Sun’s thermal radiation. In the Earth’s moderate climate zones, the infrared A-radiation reaches the Earth’s surface after being filtered by the water vapour in the Earth’s atmosphere, and is thus especially well tolerable.

The publication from the Charité Berlin and the Mainz University Medical Center has demonstrated numerous systematic methodological errors in publications claiming to show the dangers of the infrared-A component of the Sun’s radiation. In cell culture studies, irradiances were partly used which were much more than 10-fold greater than that of the maximum possible infrared-A irradiance of the Sun in the moderate climate zones or even in the tropics.

These studies ignored the fact that cells in a cell culture (which are not covered by overlying skin cells and have no connection to a blood circulation) should not be exposed to the same level of irradiance as human skin (with an intact blood perfusion, a layer of overlying cells and a horny layer), if meaningful conclusions relevant to the situation in the skin of a person are to be drawn.

An earlier publication has also brought attention to the differences in effects seen when identical irradiances are used to irradiate inanimate material having no blood circulation (resulting in a surface temperature of approx. 100°C) and human skin capable of heat dissipation via the circulation (resulting in a surface temperature of approx. 38°C) [4].

In the studies in which supposed dangers were reported, no consideration at all was given to the fact that the results seen are dependent not only on the dose of irradiation, but also on the irradiance level: Effects seen following short exposures to very high irradiances can not be interpreted as suggesting that the same result will occur if irradiation is carried out over hours using a lower irradiance level.

Additionally, some of the studies were carried out using foreskin cells obtained from infants, which are known to behave differently to skin cells.
A specific effect of infrared-A exposure which was independent of a pure temperature increase could not be identified as the reason for effects interpreted as being undesirable in the critical studies. Instead, the publication from the University of Stuttgart-Hohenheim showed that certain effects could be seen in cell cultures even in the complete absence of infrared-A exposure when only the temperature of the water bath was increased, whereas these effects were not seen even with high infrared-A irradiance levels as long as the cells were maintained under physiological temperature conditions.

Ultimately, the interpretation of possible effects and the avoidance of miss- or overinterpretations are of considerable importance: Even when, as claimed in the critical reports, an upregulation of enzymes capable of degrading collagen (e.g., the matrix metalloproteinases) or their gene expression were to occur, this can not automatically be interpreted as being detrimental in the sense of a promotion of skin ageing or even more far-reaching skin changes, since these effects are also seen during other processes such as wound healing.

Even a purported increase in free radicals can not categorically be considered as being unfavourable; the ambivalent relevance of free radicals has already been pointed out in an earlier publication [5]: in the case of special white blood cells (granulocytes), the generation of free radicals is an important mechanism of action in the defence against bacteria.

Consequently, there is no reason for specific measures against the Sun’s infrared-A (e.g., in the form of special Sun protection products), especially when the fact that infrared-A has been shown to provide some protection against the unwanted effects of the Sun’s ultraviolet radiation is considered [6]. At the same time, there is no cause for any reservations concerning the beneficial medical application of infrared-A (IRA) or water-filtered infrared-A (wIRA) radiation. However, the necessity for adequate skin and eye protection against ultraviolet (UV) in Sun's radiation remains valid, e.g., in the form of protection through textiles, sunglasses or sun protection products.

Publications:
[1] Piazena H, Kelleher DK. 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. Photochem Photobiol. 2010; 86: 687-705. DOI: 10.1111 ⁄ j.1751-1097.2010.00729.x
[2] Jung T, Höhn A, Piazena H, Grune T. Effects of water-filtered infrared A irradiation on human fibroblasts. Free Radic Biol Med. 48; 2010: 153-160. DOI: 10.1016/j.freeradbiomed.2009.10.036
[3] Gebbers N, Hirt-Burri N, Scaletta C, Hoffmann G, Applegate LA. Water-filtered infrared-A radiation (wIRA) is not implicated in cellular degeneration of human skin. GMS Ger Med Sci. 2007; 5: Doc08. Online available from: http://www.egms.de/pdf/gms/2007-5/000044.pdf (PDF) and http://www.egms.de/en/gms/2007-5/000044.shtml (shtml).
[4] Mercer JB, Nielsen SP, Hoffmann G. Improvement of wound healing by water-filtered infrared-A (wIRA) in patients with chronic venous stasis ulcers of the lower legs including evaluation using infrared thermography. GMS Ger Med Sci. 2008; 6: Doc11. Online available from: http://www.egms.de/pdf/gms/2008-6/000056.pdf (PDF) and http://www.egms.de/en/gms/2008-6/000056.shtml (shtml).
[5] Meffert H. Antioxidants – friend or foe? GMS Ger Med Sci. 2008; 6: Doc09. Online available from: http://www.egms.de/pdf/gms/2008-6/000054.pdf (PDF) and http://www.egms.de/en/gms/2008-6/000054.shtml (shtml).

[6] Menezes S, Coulomb B, Lebreton C, Dubertret L. Non-coherent near infrared radiation protects normal human dermal fibroblasts from solar ultraviolet toxicity. J Invest Dermatol. 1998; 111(4): 629-33. DOI: 10.1046/j.1523-1747.1998.00338.x

Wolfgang Müller | idw
Further information:
http://awmf.org

More articles from Health and Medicine:

nachricht Vanishing capillaries
23.03.2017 | Technische Universität München

nachricht How prenatal maternal infections may affect genetic factors in Autism spectrum disorder
22.03.2017 | University of California - San Diego

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>