Glycerin, commonly found in skin care products because it attracts water and helps skin look better, may have therapeutic value as well, according to researchers at the Medical College of Georgia. Glycerin, or glycerol, is a natural alcohol and water attractor that’s been used in skin care products for centuries, says Dr. Wendy Bollinger Bollag, cell physiologist. Glycerol also makes skin look and function better by helping skin cells mature properly.
“This is a pretty novel hypothesis that is really quite in its infancy,” Dr. Bollag says of the finding that glycerol works as a signal to help direct skin cells through their four normal stages of maturity. In the endless cycle of skin-cell production, the youngest cells move up from the deepest layer and switch from replicating as their main function to eventually becoming mature surface cells that spit out lipids to help form the skin’s protective barrier before they die.
The researchers’ findings about the signaling function of glycerol means the readily available fluid, found in its pure state on grocery store shelves and as a component of many other products, may help people with diseases such as psoriasis and non-melanoma skin cancers, that result from abnormal proliferation and maturation of skin cells, and may augment wound-healing.
Phospholipase D is an enzyme that converts fats or lipids in the external protective skin cell membrane to cell signalers. When phospholipase D pairs with glycerol, it produces a distinctive signal that directs skin cell maturation. They found that, despite its name, a channel called aquaporin 3, which is expressed in skin cells and allows only certain molecules through, is not particularly good at transporting water but is good at transporting glycerin. Inside skin cells, aquaporin 3 and phospholipase D interact. “We don’t know if it’s direct or if there is an intervening protein, but they associate,” Dr. Zheng says. They theorize that aquaporin 3 funnels glycerol to phospholipase D, resulting in phosphatidylglycerol, a lipid that appears to signal enzymes involved in skin cell differentiation, Dr. Zheng says.
“We think the glycerol is serving as a substrate to allow the skin to mature properly and, when you don’t have enough glycerol in the skin, cells don’t mature properly and that is why you get hyper-proliferative, thick skin,” Dr. Bollag says.
A mouse model for dry, flaky, unnaturally thick and slow-healing skin recently developed by researchers at the University of California, San Francisco, may help prove the Augusta researchers correct.
The genetically manipulated mice lack sufficient glycerol in their skin because they are missing the gene responsible for aquaporin 3. “That is why their levels of glycerol are reduced, because they don’t have that glycerol channel,” Dr. Bollag says. The mouse research was published in the Journal of Investigative Dermatology about the same time Drs. Bollag and Zheng were submitting their work. “We were thinking, we know why this happens,” Dr. Bollag says. Water-loving glycerol couldn’t get inside the phospholipase D cell without a channel. Consequently, the phosphatidylglycerol that results from their union doesn’t happen and neither does the resulting signal that directs normal skin cell maturation.
Another naturally occurring mouse with dry, thick skin has aquaporin 3 but lacks skin fats that are normally broken down to release glycerol, Dr. Bollag says.
When glycerol was given topically or orally to these animal models, many of the skin problems resolved. Other water-attracting agents didn’t work so well, which gives the MCG researchers more fuel for their finding that glycerol also plays a key role in normal skin cell maturation and proliferation.
They hope their findings will not only contribute to a better understanding of normal skin development but lead to more effective treatment when development is abnormal.
“For instance, in psoriasis, you have keratinocytes (skin cells) that grow too much and if we could somehow harness this signal, we might somehow be able to tell those keratinocytes, ‘No. It’s time to mature. Stop growing. Mature and form good skin. Form this good barrier,'” Dr. Bollag says. “Another instance in which you don’t get normal maturation of the keratinocytes is in skin cancer, the non-melanoma skin cancers. So here is another way that if we could potentially harness this signaling pathway, we could maybe bypass the signal that basically makes them cancer and tell them, ‘No. Mature and form skin and that’s it. Don’t become a cancer,'” says Dr. Bollag.
The MCG researcher has submitted a grant application to the National Institutes of Health to further study the signaling mechanism she and Dr. Zheng have found. The NIH supported her current studies as well.
“(Now we are) trying to find out what the signal activates,” she says. “In other words, how does the signal that is produced by phospholipase D and the glycerol actually tell the cell to mature? How does that signal then activate certain enzymes and proteins in the cell to make the cell mature? Other things we are interested in looking at are ways to manipulate the system, for instance to increase signal formation, to see if we can then increase keratinocyte formation and that would potentially be a way to harness the system to treat skin diseases.”
Glycerin / Glycerol can help with the following
Key
| May do some good |
Glossary
Lipid
Fat-soluble substances derived from animal or vegetable cells by nonpolar solvents (e.g. ether); the term can include the following types of materials: fatty acids, glycerides, phospholipids, alcohols and waxes.
Psoriasis
An inherited skin disorder in which there are red patches with thick, dry silvery scales. It is caused by the body making too-many skin cells. Sores may be anywhere on the body but are more common on the arms, scalp, ears, and the pubic area. A swelling of small joints may go along with the skin disease.
Enzymes
Specific protein catalysts produced by the cells that are crucial in chemical reactions and in building up or synthesizing most compounds in the body. Each enzyme performs a specific function without itself being consumed. For example, the digestive enzyme amylase acts on carbohydrates in foods to break them down.
Protein
Compounds composed of hydrogen, oxygen, and nitrogen present in the body and in foods that form complex combinations of amino acids. Protein is essential for life and is used for growth and repair. Foods that supply the body with protein include animal products, grains, legumes, and vegetables. Proteins from animal sources contain the essential amino acids. Proteins are changed to amino acids in the body.
Microgram
(mcg): 1/1,000 of a milligram in weight.
Cancer
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.