It is well known that human beings can identify odours through the 350 different types of olfactory receptors in the nose, which start a signalling process that then messages the brain. The receptors jointly work to provide a sense of smell.
In a new study published in the Journal of Investigative Dermatology, it was found that these olfactory receptors also existed in the cells that form the outermost layer of the skin, called the keratinocytes. Activating these receptors increased the receptivity and the rate of cell division and their migration. The study discovered that the presence of these receptors on the skin increases the rate at which the wounds would heal.
Although these receptors were known to have existed in all human issues, it was thought that their function was limited to detecting odours apart from the receptors in a few cell types such as sperm, colon and the prostate. The study paper described the found fact, "The activation of the olfactory receptors in sperm influences its swimming direction and speed, while in colon cells it induces a release of serotonin (a process that is part of the enteric nervous system - also nicknamed our "second brain").
The study found that the skin cells possess a receptor called OR2AT4 which responds to the scent of sandalwood, frequently used in incense sticks and perfumes. "We were able to activate this receptor using Sandalore, a synthetic sandalwood scent. Using samples that included cultured keratinocyte cells and human skin, we discovered that activating OR2AT4 triggered a signal pathway that led to a higher concentration of calcium in the cells," said the study.
Hanns Hatt, author of the paper and professor of Cellphysiology at Ruhr-Universität Bochum, the university that collaborated with the Deramatology Department at the University of Munster for the research, said that this resulted to a rise in the proliferation and a quicker migration of keratinocytes - processes which facilitate wound healing. Scratching experiments on isolated human skin tissue confirmed this wound-healing effect.
In addition to OR2AT4, they found a variety of olfactory receptors in the melanin producing cells as well called melanocytes, situated at the bottom layer of the epidermis and in fibroblasts cells. It is a highly important part of the wound-healing process. "The function of these additional receptors is something we are planning to characterise in future experiments," Hanns said.
He states that the results so far show that these olfactory receptors in human skin have potential therapeutic benefits. "Understanding the mechanism could be a possible starting point for new drugs and cosmetics. Sandalore, for example, could have potential use as a topical ointment that could have anti-ageing properties or accelerate wound healing," Hanns said.
The study also cautioned to keep in mind that concentrated fragrances should be handled carefully until there is confirmation of the functions the different types of olfactory receptors in skin cells have. "Besides the positive effect of Sandalore on the receptor OR2AT4, we could well discover that other receptors elicit negative effects on human skin cells," he said.