Stem Cells and Scalp Hair Regeneration
Human hair growth of is a very complex process. Hair loss is based on numerous factors including genetics, environment issues, hormonal influence, and health condition. Infections, autoimmune disorders, iron deficiency, and metabolic problems can also affect hair loss. Nutrition plays another key role determining whether or not ones’ body will produce healthy hair. Male pattern baldness, or androgenetic alopecia (AGA), is X-linked (affected by maternal genetic influence).
Hair typically grows at a rate of one half inch per month. At any given time most people have 100,000 to 150,000 hairs on their scalp. One single strand of hair is comprised of multiple microscopic components. Each of these components contributes to ones’ ability to grow and maintain healthy hair. Human beings produce three different types of hair, while the sort of hair found on a human scalp is known as terminal hair.
Hair Growth Basics
Humans constantly grow and lose our hair. Your scalp sheds dead or damaged hair on a daily basis. Alopecia obviously occurs when the hair we lose is not replaced by new growth. An undesirable trend occurs as individuals grow older and begin losing primary terminal hairs on the scalp area, replacing them with vellus hairs. Vellus hairs are very similar to what is present in a newborn infant before the scalp filled in with permanent hair. There are three phases in the hair growth cycle.
Phase One-Active Growth-Anagen
In the anagen phase the majority of ones’ hairs strands are actively growing. Anagen typically lasts 3-4 years but can in some cases be as long as nine years. Because of a shortened anagen phase, some may notice that their hair is becoming finer and thinner with less color. At any given time, most of our hair is in the anagen growth phase. Only a small percentage of our hair strands are in one the catagen or telogen phases.
Phase Two-Regressive Phase- Catagen
The catagen, or hair loss phase, usually lasts 3-4 weeks. On any given day, most people shed 75-100 scalp hairs. These hairs are lost to make way for new growth hair that will soon appear. This hair loss may be associated with brushing or shampooing your hair.
Phase Three-Resting Phase- Telogen
Telogen phase lasts a few months and is the phase where your hair is resting or sleeping. Hairs in the resting phase are neither growing nor falling out. They are just “resting”. This means that there is no active growth going on with that hair strand.
There are a variety of hair restoration techniques and cosmetic hair procedures available today. Your hair restoration surgeon will match hair types and hair direction to maintain optimal appearance. Some have advocated the uncontrolled injection of Platelet rich plasma (mostly growth factors and a few stem cells) at the time of hair restoration surgery. Medications are sometimes also used. Rogaine and Propecia are, at present, the only two baldness medications approved for use by the FDA. They are more effective for maintaining hair already on the scalp than they are in re-growing hair. These medications cannot restore the robust healthy follicles in androgenic alopecia and can have many untoward side effects, some of may become permanent even after discontinuing the medication. Over the last 10 years, there has been much hype and hope for an effective baldness treatment using stem cell technology.
Scientists have thought for many years that people suffering from hair loss had a depletion of hair follicles and follicular stem cells that are necessary to grow hair. Dermatology professor George Cotsarelis, MD, of the University of Pennsylvania, published a study in 2011 in the Journal of Clinical Investigation showing that bald people have the same number of follicle stem cells as those with hair(1). Cotsarelis analyzed skin cells from the bald and non-bald parts of the scalp of people with androgenetic alopecia. Using different markers to distinguish between stem cells and hair follicle progenitor cells, they were able to tally the number of each type and found that there was the same number of follicle stem cells in the skin from bald scalps as there were in the skin from the non-bald scalps. The inability of those scalp stem cells to develop into the type of cells that make hair follicles may be the underlying cause of male-pattern baldness. So if we could identify the signals that stimulate the stem cells to produce more hair follicle progenitor cells, then it should be possible to generate bigger hair follicles that will grow hair. Such studies have shown that men with male pattern baldness retain their stem cells in follicle roots but these stem cells lack the ability to initiate hair regeneration. We know that these follicle stem cells need signals from within the skin to grow hair, but the source of those signals has been unclear.
A recent landmark report from Yale (Horsely, et. al.; Sept. 2, 2011 issue of Cell) demonstrates the efficacy of adipose derived stem cells in activating these dormant hair follicles and growing new hair (2). Horsley reported that when hair dies, the layer of scalp fat that comprises most of the skin’s thickness shrinks. With onset of hair growth, the fat layer expands in a process known as adipogenesis. There is a type of stem cell involved in creation of new fat cells — adipose precursor cells — that was required for hair regeneration in mice. These precursor cells are the same stem cells isolated in stromal vascular fraction by the process used at the Phoenix Stem Cell Treatment Center. These Yale investigators also found these precursor cells produce signal molecules called PDGF (platelet derived growth factor), which are necessary for hair growth in mice. It has not been shown that PDGF has the same chemical signal effect on human hair growth. It is known that PDGF is a powerful activator of human adult mesenchymal stem cells.
The PSCTC Protocol:
PSCTC is studying the effects of controlled micro-implantation of stromal vascular fraction (SVF-mostly stem cells with some growth factors) derived from autologous human fat into the scalp in men with alopecia. An automatic micro-injection system allows the introduction of depth controlled doses of fat derived autologous stem cells (stromal vascular fraction) in a systematic pattern to targeted areas. The micro-injection system is painless and can be done as an outpatient procedure after SVF/stem cell harvesting with a mini-liposuction under local anesthesia.