Featured Research

from universities, journals, and other organizations

UV Radiation Induces Vitamin A Deficiency In Skin

Date:
March 31, 1999
Source:
University Of Michigan
Summary:
That golden tan may look terrific, but its cost to your skin---premature aging, wrinkles, sags, blotches, and an increased risk of skin cancer---may be more than you want to pay. While it is well known that ultraviolet radiation from the sun has many effects on skin, scientists still don't fully understand how UV causes so much damage.

ANN ARBOR---That golden tan may look terrific, but its cost to your skin---premature aging, wrinkles, sags, blotches, and an increased risk of skin cancer---may be more than you want to pay. While it is well known that ultraviolet radiation from the sun has many effects on skin, scientists still don't fully understand how UV causes so much damage.

University of Michigan scientists have discovered an important new piece of the puzzle, however, which they describe in an article to be published in this week's Nature Medicine.

"We found that ultraviolet irradiation blocks the ability of skin cells to recognize and respond to an essential nutrient called retinoic acid, which skin cells make from vitamin A or retinol," said John J. Voorhees, M.D., the Duncan and Ella Poth Distinguished Professor of Dermatology in the U-M Medical School. "The inability to respond to retinoic acid triggers a cascade of biochemical changes that upsets the normal balance between healthy and dying skin cells. In essence, UV causes a functional vitamin A deficiency in human skin.

"We also found that pretreating skin with retinoic acid---the active form of vitamin A---before UV exposure limits the extent of the harmful biochemical changes."

According to Gary J. Fisher, Ph.D., U-M senior associate research scientist in dermatology and the study's co-author, UV causes a major loss of retinoic acid receptors found in human skin cells. "Retinoic acid receptors are the molecular mediators of the biological actions of vitamin A. When retinoic acid receptors are lost, it is as if the skin has no vitamin A," Fisher explained. "This is a bad situation because vitamin A is required for normal skin development and function. Retinoic acid receptors, when activated by retinoic acid, transfer genetic instructions from DNA to the cell's protein-producing factory telling it to assemble proteins needed for skin cell function.

"Eight hours after skin was exposed to UV radiation in our study, amounts of retinoic acid receptor messenger RNA and protein were as much as 70 percent lower than control levels. They remained below normal levels for more than 24 hours after exposure," Fisher said. "When skin was pre-treated with retinoic acid and then exposed to UV radiation, the amount of messenger RNA and protein still dropped, but it rebounded to normal levels within 16 hours. Applying retinoic acid after UV exposure had no effect."

Voorhees added that when the biochemical retinoic acid receptor pathway is shut down, other dangerous skin changes---which also occur in response to UV exposure---can proceed unchecked. This process was first described by Voorhees, Fisher and their colleagues, in a series of articles published in Nature, New England Journal of Medicine, and Journal of Clinical Investigation.

"In this process, UV activates a protein complex called AP-1, which causes production of large amounts of enzymes called matrix metalloproteinases or MMPs," Voorhees explained. "These MMPs break apart and degrade collagen and elastin, the major structural materials in skin. Although the broken-down collagen and elastin are replaced, the repair process is imperfect. This imperfect repair results in a tiny defect in the skin. With repeated UV exposures, the defect grows and eventually results in the wrinkled appearance of sun-damaged skin. In addition, the biochemical changes associated with activation of AP-1 and production of MMPs promote skin cancer."

Although additional research will be needed to completely understand the complex relationship between the retinoic acid receptor pathway and the pathway responsible for producing enzymes that destroy skin collagen, Voorhees and his colleagues believe the two may exist in a state of dynamic balance. This dynamic balance may be necessary to maintain healthy skin. "However, if the retinoic acid receptor pathway is disabled by UV radiation, the destructive pathway has free rein to inflict a great deal of damage," Voorhees said.

Understanding how these two biochemical pathways work in human skin may lead to new medications or treatments that could block the harmful effects of UV radiation. "Our findings suggest that applying retinoic acid or retinol to skin before going out in the sun might be beneficial. However, before vitamin A or retinoic acid can be recommended as a preventive against sun damage, formal clinical trials must be performed to know whether this notion is correct," Voorhees added.

Until then, Voorhees emphasized that the U-M study reinforces the importance of protecting skin from UV exposure. "Daily exposure to UV radiation---even amounts too small to produce skin redness---is particularly dangerous, because the skin never has time to restore normal levels of retinoic acid receptors."

In addition to Voorhees and Fisher, co-investigators on the U-M study were ZengQuan Wang, Mohamed Boudjelal and Sewon Kang all from the Department of Dermatology in the U-M Health System. The U-M holds a patent on the use of retinoic acid or retinol to prevent wrinkles and skin damage caused by UV exposure from the sun. The research was funded by the Babcock Endowment for Dermatological Research, the Dermatology Foundation (SK) and the Johnson & Johnson Corporation.


Story Source:

The above story is based on materials provided by University Of Michigan. Note: Materials may be edited for content and length.


Cite This Page:

University Of Michigan. "UV Radiation Induces Vitamin A Deficiency In Skin." ScienceDaily. ScienceDaily, 31 March 1999. <www.sciencedaily.com/releases/1999/03/990331063314.htm>.
University Of Michigan. (1999, March 31). UV Radiation Induces Vitamin A Deficiency In Skin. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/1999/03/990331063314.htm
University Of Michigan. "UV Radiation Induces Vitamin A Deficiency In Skin." ScienceDaily. www.sciencedaily.com/releases/1999/03/990331063314.htm (accessed July 24, 2014).

Share This




More Health & Medicine News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. Video provided by Newsy
Powered by NewsLook.com
Condemned Man's US Execution Takes Nearly Two Hours

Condemned Man's US Execution Takes Nearly Two Hours

AFP (July 24, 2014) America's death penalty debate raged Thursday after it took nearly two hours for Arizona to execute a prisoner who lost a Supreme Court battle challenging the experimental lethal drug cocktail. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com
China's Ageing Millions Look Forward to Bleak Future

China's Ageing Millions Look Forward to Bleak Future

AFP (July 24, 2014) China's elderly population is expanding so quickly that children struggle to look after them, pushing them to do something unexpected in Chinese society- move their parents into a nursing home. Duration: 02:07 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins