The body’s ability to heal is astounding. Researchers have invested decades in understanding how it works but only in recent times have these findings been applied to beauty and anti-aging.
It is beyond the scope of this article to review every growth factor and pathway related to healing and anti-aging; but here’s a brief review of growth factors you see on product labels and research related to them. Also included are new findings in healing; connections between retinol, resveratrol and growth factors; and an overview of growth factor-containing spa products.
Age Gracefully and Scarlessly
Celeste Hilling wrote about growth factors a few years ago.1 She described the growing body of medical research aimed at advancing healing and tissue regeneration scarlessly. Through this research, human growth factors (HGFs) were identified as critical to healing and with huge skin rejuvenation potential.
According to Frank Dreher,2 aged skin has an altered growth factor response similar to a chronic wound. This is why growth factors for skin healing can reduce the signs of aging. They promote dermal fibroblast proliferation and stimulate the formation of the extracellular matrix (ECM) including collagen and hyaluronic acid—especially when combined. “Today, there is evidence that the signs of aging skin may be best improved with a balanced mixture of growth factors,” Dreher writes.
But how do they work? Dreher explained that growth factors play key roles in the body for regulating cell processes. Paired up with cytokines, they help to regulate cell division, differentiation, movement and adhesion, trafficking, activation, apoptosis and survival. Also, only low concentrations are needed for these effects.
Clinical studies have found topical growth factors reduce healing time; particularly epidermal growth factor (EGF), fibroblast growth factor-2 (FGF-2), transforming growth factor-beta (TGF-β) and platelet-derived growth factor (PDGF).2 Each has different effects. For example, TGF-β helps stimulate collagen, inhibit cellular breakdown and enabl cells to locate nutrients.1
Interestingly, according to Dreher,2 wounds in adults heal with scar formation, which restores tissue integrity. But in utero, rapid and perfect skin repair occurs. This was validated by Lali et al.,3 who explained in the animal kingdom, there are five forms of TGF-β. Only TGF-β1, -β2 and -β3 are expressed by mammals. Embryonic wounds express high levels of -β3 and low levels of -β1 and -β2, whereas adult wounds predominantly express -β1 (and -β2).
In relation, studies have shown that levels of TGF-β1 and its down-stream targets, i.e., connective tissue growth factors (CTGF), are significantly reduced in aged human skin.2 In fact, topical retinol, known for its anti-aging effects, has been shown to stimulate the TGF-β/CTGF pathway to help regulate the homeostasis of the ECM.4
Another anti-aging favorite, resveratrol, has been shown in skin models to increase the expression of growth factors (HBEGF, IGF1, NGF and TGF) and decrease the expression of inflammatory and skin-aging molecules (IL-1, IL-6, IL-8, COX-2, TNGRSF). However, this plant polyphenol has drawbacks, including its low bioavailability due to metabolism. Thus, companies have modified its structure to improve its application.5
Go with the Flow
To aid TGF-β’s fibroblast and ECM activities, increasing blood flow to the damaged or aged site can speed the healing process. That’s where agents like granulocyte-macrophage colony-stimulating factor (GM-CSF) come in.1 GM-CSF restores the response of blood cells to the skin’s breakdown. As a bonus, factors that increase blood flow also help to counteract infection, e.g., in acne; even skin discoloration; reduce rosacea; and brighten dullness.1
Another facet of both wound healing and aging is inflammation, and interleukin-10 (IL-10) (known as cytokine synthesis inhibitory factor) blocks inflammation. This supports cell defenses and initiates the post-inflammatory phases of healing.3 In relation, interleukins 3, 6, 7 and 8 (IL3, IL6-8) help to enhance natural cell defenses, balance cell nutrients and improve the anti-inflammatory response.1
Connexins (Cx) also have gained interest for wound closure and inflammation. A number of these junction proteins are expressed in the epidermis and dermis, and are acutely regulated following injury. Interestingly, their normal regulation is lost in non-healing wounds, suggesting a novel target for healing.3
Growth Factors and Spa Skin Care
Growth factors are found in a number of clinical brands in the spa industry, the most prevalent being EGF or “RH-oligopeptide 1,” on the ingredient label.
GlyMed Plus uses EGF in its DNA Reset Face & Neck Cream, where it is nano-encapsulated for improved anti-wrinkle and healing effects. On growth factors, Christine Heathman, CEO and founder of GlyMed Plus commented, “[EGF] ... operates via the EGF receptor on epidermal cells to grow across the wound. However, it also has effects on smooth muscle cells and fibroblasts.”
EGF is used in Rhonda Allison’s Growth Factor Serum and Serum Plus, and Growth Factor Gel, where it aids in tissue regrowth after microdermabrasion or chemical peels, and provides healing benefits for problematic, wounded, photoaged or acneic skin. The company complexes EGF with urea glycolysates, DHEA and pyroglutamic acid to intensify the growth factor in its enhanced epidermal growth factor (eEGF), which can be found in its Elite eEGF. “[Growth factors] have wound healing and repair abilities. . . We use them after skin rejuvenation to help repair and strengthen new, healthy cells,” said Shannon Esau, director of accounts and education for the company.
TGF-β1, or “Polypeptide-22” on a label, is used by Jan Marini in its Regeneration Booster, Transformation Face Cream and Serum and Transofrmation Eye Cream. It is used to help maintain youthful, healthy skin. “[TGF-β1] appears to stimulate a type of collagen that we don’t produce after the age of 30. It is also critical to wound healing and is an important factor in collagen remodeling and synthesis,” explained Jan Marini, founder and CEO.
Along similar lines, Skinprint uses self-regeneration stem cell technology (SRST) to activate skin receptors and release repair and growth factors unique to an individual’s needs in its Skintellect MicroGel Cream. “Initiating your own skin to produce the needed growth factors is a more effective way to get the needed growth factors to provide the anti-aging benefit you’re seeking with maximum safety,” noted Robert Manzo, president and CEO. He furthered, “By enhancing epidermal stem cells to become more active via this personalized approach, keratinocytes will be more robust, dermal tissue will regenerate and the skin will appear smoother and brighter.”
Rachel Grabenhofer is the managing editor of Cosmetics & Toiletries, Skin Inc.’s sister brand for cosmetic chemists. She’s a member of the Council of Science Editors and Society of Cosmetic Chemists, and for the past several years, has led judging panels to honor the best ingredients in cosmetics.
A close up view of fibroblasts with fluorescent stain