Stem Cells, Growth Factors & Cytokines in Skincare
When it comes to skin health, does the “social activity” of your skin cells ever cross your mind? In fact, were you aware that your skin even had a social life? Well-understood biology confirms that your cells have VERY active social interactions going on, and are in constant communication with one another, giving off messages that instruct coordinated biological events, influencing how cells function and behave. All nucleated human cells, outside of red blood cells, communicate with one another by giving off messenger proteins called cytokines and growth factors. These proteins, each one carrying its own unique “instruction”, are widely recognized by the medical literature, including publications such as the Journal of Drugs in Dermatology, as the molecular “keys” that unlock the full potential of your cells to stimulate and optimize skin health. As we begin to grasp the basic fundamentals behind aging, and aging skin in particular, we come to the realization that no matter what research proven ingredient we expose our skin to, if we aren’t optimizing cellular communication, these powerful actives won’t be performing at their highest level. Growth Factors and cytokines allow us to achieve this very objective. However, not all growth factors and cytokines are created equal.
In order to discuss the effects growth factors and cytokines have on the skin, it is necessary to understand it is their combined “pattern” that determines what their effect will be (all cells secrete dozens if not hundreds of growth factors and cytokines.) That pattern is determined by the genetic machinery of the cells being cultured to obtain the growth factors and cytokines - most frequently stem cells from liposuction fat, stem cells from bone marrow, or fibroblasts from male infant foreskins . The role of growth factors and cytokines in wound healing have been studied extensively; they serve multiple functions including regulation of the immune system, promoting collagen synthesis, quenching inflammation, increasing inflammation, reducing scar tissue, and so on.
I want to place emphasis on the ability of these proteins to either INCREASE or DECREASE inflammation. This is their most important aspect when it comes to comparing the different sources of growth factors and cytokines, and ultimately what physiological effect they will have on the skin. It should come as no surprise to anyone that inflammation and aging are synonymous; they are one in the same. Any topical product meant to be anti-aging, in the truest sense of the term, must be strongly anti-inflammatory.
Before I dive into the different sources of these proteins, let’s briefly discuss basic “mechanism of action”. As previously mentioned, these biological signals are how cells “talk” to each other. They work in sort of a “lock and key” fashion. Think of the growth factor or cytokine as the “key”, and the receptor on the surface of the cell as the “lock”. A growth factor (“key”) gets synthesized within a cell; that cell then releases the growth factor where it travels to its neighboring cells and attaches to a receptor on the surface of those cells (“lock”), activating a unique biological response. A cascade of biologic signals gets sent to the heart of the cell, the nucleus, causing a change in genetic expression. The behavior of the neighboring cells is changed. This process continues, to complete the task at hand. This is cell-to-cell communication in its simplest explanation.
Now let’s move on to where these signal proteins are sourced from, and why that is important. The terms growth factor, cytokine and stem cells get thrown around quite often in skin care marketing, with a ton of misinformation being spread around as to what these actually mean. Often it’s the “magical” plant stem cell that gets sensationalized in the skin care arena. Without spending too much time diving into this, when it comes to cell-to-cell communication within HUMAN skin, plants serve no purpose or function. It is physiologically impossible for plant stem cells to communicate with human cells, they just don’t speak the same language. That’s not to say they don’t have some therapeutic value, as research shows potential anti-oxidant capability from certain plant species. That being said, it is vital that we expose the skin to human-derived growth factors and cytokines, in order to achieve the physiological effect we desire.
There are hundreds of different types of growth factors and cytokines. Within the realm of human-derived growth factors, we have multiple cells we can utilize to extract these powerful cellular messenger proteins. Let’s first discuss the process of “extraction”, so you get a better understanding. An easy way to recognize that you have a human derived protein product is when you read the label and it says “_________ conditioned media”, with the blank space being the preferred cell of choice. Independent of the cell used (we will discuss these next), the culturing process is as follows:
-In the lab, the cell of choice is placed into a “glorified” petri dish that contains a media solution. We like to call this a “nutrient-rich broth”. This media is basically a nutritional source for the cells to feed off of and grow.
-As the cells grow, they begin to replicate themselves, exponentially increasing the amount of cells within the culture/media.
-While growing, the cells start to give off/release the growth factors and cytokines that they naturally produce, into the broth/media.
-Once this process is complete, the living cells are filtered out of the broth/media, and what you are left with is the growth factors, cytokines, enzymes, exosomes and other material that the cell released.
-The media is now “conditioned” and ready to be processed and formulated for topical application.
Barring a few additional steps that would be too technical to discuss, this is the process, simplified. Whatever cell is used, each gives off its own unique portfolio of proteins, whose net pattern determines the physiological effect it has on the skin.
There are three main cell types cultured for topical application; Fibroblast cells, Adipose (Fat) Stem Cells and Bone Marrow Stem Cells. The pattern of proteins they produce are vastly different from one another.
Fibroblast Cells: Even though still widely used, this is considered “first generation” growth factor skin care. Fibroblast cells are the dominant cell within connective tissue. These cells are what synthesize key structural protein such as collagen and elastin. When cultured (usually from neonatal tissue), just like any other cell, they begin to release the messenger bio-signals. Fibroblasts, however, are what’s considered “low-ranking” cells. The amount of cytokines and growth factors they release into the media are minute. They are WEAK producers of the bio-signals. With some even teetering on the inflammatory side. Manufacturers will compensate for this by adding a larger dose of the media in their products. This, in no way, improves efficacy, it simply makes the product stink (human protein has a distinct smell!).
Adipose (Fat) Stem Cells: Sourced from middle-aged donors, a byproduct of liposuction waste, they are cheap, easy to culture and grow in abundance. The inherent problem with these cells is that they serve no role in controlled healing within the body. Fat Stem Cells have one fate in life, and that is to create more fat. Fat serves auxillary endocrine function, and when these stem cells are cultured, the portfolio of proteins that get released into the media are strongly PRO-INFLAMMATORY. Metabolically active hormones such as leptin, and cytokines such as TNF-a and IL-6 could disrupt healthy biochemical pathways. Remember that aging and inflammation go hand-in-hand. If the objective of a daily skin care product is to be anti-aging, it is strongly encouraged you avoid the usage of Adipose Stem Cell-derived growth factors and cytokines.
Bone Marrow Stem Cells: This is the master stem cell that controls healing and regeneration throughout the entire body. In fact, it is the only MOBILE stem cell that patrols the body looking for injury. Upon discovery of that injury, it initiates a regenerative response to heal. When cultured (sourced from healthy young adult donors), bone marrow stem cells release an abundance of growth factors and cytokines, whose portfolio is predominantly ANTI-INFLAMMATORY and PRO-HEALING, such as TGF-b3, IGF-1 and IL-10. It is this net-pattern of protein that provides an unparalleled anti-aging response on the skin. No other cell in the body has the ability to fight inflammation quite like this.
It is also important to remember that growth factors do not exist in isolation, and no product should contain a single protein molecule (think the EGF cream craze in the late nineties). You want to use a product that has a physiologically balanced composition of these proteins, and a product whose net-pattern of bio-signals is anti-inflammatory. As an aesthetic practitioner, I encourage you to dive deeper into the research of this technology and constantly ask questions about the products manufacturers are selling you. Armed with this knowledge, you have the power to choose formulations that truly optimize this social network that exists within your skin, and have it work with you, not against you.
Your skin is talking, are you listening?
