The reported applications of stem cells are numerous. But are stem cells really a breakthrough or just marketing hype?
Ruslan Semechkin, Ph.D., wrote a very interesting article about it:
One of the earliest applications of stem cell technology in the skin care field was by Amatokin, whose first product was developed in Russia and launched in the United States in 2005. Since then, however, there is a whole new generation of stem cell-related skin care products. Stem cells are the new buzzword in skin care. Common questions surrounding stem cells include: Are they (a) the latest and greatest advance in anti-aging skin care?; (b) revolutionizing the art and science of cosmeceuticals?; or (c) just a lot of hype? So which is it? The truth is probably (d) all of the above.
Like many other technologies in cosmeceuticals, the source of the active ingredient, the veracity of the claims and the underlying science, are quite literally, all over the board. Let’s look at the different types of stem cells and consider the sources, the science and how they are used in skin care products. It’s important that the skin care industry understand the science behind stem cells, and communicate fairly and effectively.
What Are Stem Cells?
Stem cells are a part of all living things: plants, animals and humans. They have the remarkable ability to develop into different cell types and continue to proliferate (divide) almost indefinitely. These two properties are what make stem cells so valuable in many fields, including tissue repair and skin rejuvenation. Although there is still much debate in the scientific community as to the actual process of aging, one theory is as we age the pool of stem cells in our bodies gets smaller, and correspondingly our ability to heal ourselves or simply replace damaged cells decreases. The supposition behind all cosmeceutical applications of stem cell-derived ingredients is this process can somehow be reversed. This has generated tremendous interest in the use of human stem cells in skin care; however, one of the most important things to understand is live human stem cells are not being applied directly to the skin; rather the stem cells are cultivated, processed and the resulting extract used as an ingredient.
As a cosmetic ingredient, there are many sources of stem cells, from both plants and humans.
Plant Stem Cells
Plant Stem Cells, more commonly known as meristem cells, are frequently derived from apples, melons, roses or rice plants. These plant-based stem cells have properties not unlike antioxidants, and can be found in many different anti-aging formulas.
But do meristem cells derived from plants stimulate the body’s human stem cells? No. Plant stem cells are just a decent source of antioxidants, apparently nothing more, nothing less. It’s a clear case where marketing has spoken louder than science.
Human Stem Cells
While it is logical to assume human stem cells will provide a better source of ingredients than plant stem cells, not all human stem cells are born equal. There are basically two main classes of human stem cells: pluripotent and multipotent. Pluripotent stem cells have the ability to become almost any cell in the body and are derived from oocytes (eggs) or from genetically reprogrammed adult cells. If the stem cells are derived from eggs, the eggs can be fertilized—embryonic stem cells (ESC); or unfertilized—parthenogenetic stem cells (PSC). Pluripotent stem cells derived from cells that are in their final form, so called adult cells, are called induced pluripotent stem cells (iPS). Multipotent stem cells—for example, mesenchymal stem cells—are stem cells that have limited capabilities and can only form different cell types within the same “germ layer—i.e., closely related cell types such as hair and nail, or bone and cartilage.
The potential for stem cells to cure diseases rather than just treat the symptoms has made them a very attractive subject for medical research and is known as Regenerative Medicine.
Indeed, the medical community has used multipotent stem cells to treat a number of conditions for many years. The process involves extracting stem cells from an individual (usually from the bone marrow), expanding those cells, adding growth factors and then implanting them back into the same individual. Such “autologous” treatments have been used for more than 30 years to treat leukemia.
However, because of their ability to become any cell type, pluripotent stem cells offer much greater therapeutic potential. There are currently a number of clinical trials underway using ESC cells to treat individuals with acute spinal cord injury and individuals with macular degeneration. Although the research and clinical development looks promising, there are a number of issues associated with using an ESC. First, the fact that a viable embryo is destroyed in order to create the ESC is ethically unacceptable to many people. Second, implanting cells from one individual to another—allogenic treatment—usually results in the tissue being rejected by the recipient’s immune system. To avoid this, strong immune-suppression regimens are used that by themselves, are dangerous and painful.
PSC are a viable alternative to ESC, potentially offering solutions to both these issues. Literally derived from the Greek for virgin birth, parthenogenesis takes unfertilized eggs and activates them without introducing sperm, to create pluripotent stem cells.
Skin Care Applications
There are a number of companies that use stem cells derived from adult tissue, usually discarded foreskins, and skin tissue discarded from abdominoplasties (tummy tucks, etc). These adult skin stem cells reside in the basal layer of the epidermis and remain dormant until they are activated by tissue injury or disease. Such multipotent stem cells only have a limited ability to differentiate and proliferate, and contain mostly epidermal growth factors.
Lifeline Skin Care, launched in 2010 by International Stem Cell Corp. (ISCO)—a publicly traded biotechnology company focused on using pluripotent stem cells derived via PSC to find cures and study diseases, particularly those of the brain, liver, pancreas and eyes—uses PSC.
Lifeline’s scientists have developed and patented a process to extract various bioactive growth factors, peptides and enzymes from these PSC; however, the peptides by themselves would be useless as they quickly breakdown and lose their potential to interact with skin cells unless they are stabilized. This is true for all stem cell extracts; however not every skin care product addresses this issue, in large part because of the complexity involved and the R&D resources required to find a solution. Lifeline also figured out how to encapsulate the peptides in a liposomal bi-layer delivery system that would both provide adequate protection, yet also release the peptide after they have been absorbed by the skin.
ISCO’s scientists have taken biopsies from human subjects and then isolated and cultured fibroblast cells from these samples. After treatment with HSC-XTM (Lifeline’s patented stem cell extract), the gene expression levels were measured for elastin, two types of collagen, keratinocyte growth factors, fibroblast growth factors and epidermal growth factors using an extremely sensitive technique called qPCR. All six genes that were examined showed significantly increased expression levels, leading to increased amounts of collagen and elastin, resulting in improved firmness and elasticity of the skin.
For now, there aren’t any credible science, either in vitro or in vivo, that supports the efficacy of plant stem cell extracts. The prevailing opinion is plant stem cells probably don’t relate to skin stem cells at all. The good news: They’re probably not bad for skin; but are they good for skin? The jury is still out on that.
Ruslan Semechkin, Ph.D., is president and CEO of Lifeline Skin Care, a subsidiary of International Stem Cell Corp. Semechkin joined International Stem Cell as the head of the neurology division in December 2008 and was appointed vice president in June 2010. Semechkin was trained in medical genetics, physiology and business management, with an undergraduate degree from Moscow State University. He earned his Ph.D. in physiology from Anokhin Research Institute, a Russian Academy of Medical Sciences. He is an active member of the Society of Cosmetic Chemists and the International Society for Stem Cell Research. He has lectured on innovations in stem cell biology, including the use of stem cells in neurology and skin regeneration. Semechkin’s scientific papers have been published in peer-reviewed medical and scientific journals, including Cell.
ISCO has filed its own patent applications covering specific pluripotent hpSC lines and methods to produce new PSC lines for research, therapeutic and commercial uses. As of Jan. 1, 2010, the company had 47 U.S. and international patent applications across eight patent families. The company continues to make PSCs freely available to academic collaborators worldwide.
I hope this article has clarified you doubts and question about stem cells.