In this article we will offer a brief explanation of how stem cells work in hair growth. The idea of this treatment is to use stem cells, which are cells that can transform themselves into other specialized cell types, such as the components of hair types of cells and inject or transplant them into your scalp to help promote hair growth. This is NOT a hair transplant procedure. It is a stem cell procedure.
In our office we offer bone marrow derived stem cells and PRP therapy alone for hair loss. This article will not necessarily compare one treatment to another. This discussion is best offered in the examination room when we have had the opportunity to access the hair loss of the patient. What this article will focus on is the common aspects of these three hair loss treatments and how they can promote hair growth.
A brief explanation of the three treatments.
- Stem cell treatment for hair loss: Bone marrow stem cells are taken from your bone marrow drawn from the iliac crest of the pelvis in a simple procedure. The bone marrow contains stem cells and the healing growth factors found in PRP therapy.
- PRP treatments involve collecting a small amount of your blood and spinning it in a centrifuge to separate the platelets from the red cells. The collected platelets are then injected into an area of thinning hair. This stimulates hair regeneration in many people. The treatment is aptly named Platelet Rich Plasma therapy as it is blood plasma that is rich is platelets.
Hair loss treatment: Getting the stem cells in your hair follicles and “bulge” to start growing hair again.
In August of 2018 researchers writing in the journal Stem cells international (1) discussed the role of stem cells in treating Alopecia by way of hair follicle regeneration and neoregeneration.
Here are their learning points:
- Hair follicles have a niche for mature stem cells—hair follicular stem cells (HFSCs)—a so-called “bulge” in the attachment region of arrector pili muscles, (the small muscles attached to hair follicles). (Note: There are stem cells in your hair. They are just not active hair stem cells– this can lead to hair loss – see below).
- Hair follicular stem cells can take part in the regeneration of epidermal cells and the structure of hair follicles and sebaceous glands (these glands secrete the hair oil that healthy hairs need.)
- The researchers explain that: Stem cells of the “bulge” can remain in their niche where they self-regenerate, but they can also move down to the hair matrix region, where they become progenitor cells which then form an internal hair follicle and the hair stem.
- In other words, the stem cells can become the building block of new hair when active and may reverse hair loss.
- There is a second type of stem cells within the hair follicle. The dermal papilla cells (DPCs) DPCs play an important role in induction and regulation of hair growth and the formation of new hair follicles. Signals from DPCs activate stem cells in the “bulge” to start hair growth.
The researchers point out that most of these stem cells live in a “dormant state,” and that their activation is essential for hair growth.
Stem cell Hair loss treatments: Activating these stem cell hair follicles
In numerous articles on this website I discuss how stem cells and growth factors introduced into damaged joints activate the native stem cells in that joint to restart the healing process. This is no different when it comes to hair loss. We know that there are many stem cells in the hair follicle, so the problem is not the number of stem cells, BUT, a problem of getting these dormant cells active again and growing hair.
A listing of the common growth factors of stem cell and PRP hair loss treatment and what they do.
- Hepatocyte growth factor (HGF) and HGF activator enhance the proliferation of hair follicle epithelial cells. (The stem cells send signals for hair to grow).
- Epidermal growth factor improves the activity and growth of follicle outer-root sheath cells
- Basic fibroblast growth factor b-FGF improves the advancement of hair follicles
- Vascular endothelial growth factor (VEGF) improves peri-follicular angiogenesis (new blood vessels to get new blood and more growth factors to the site prior to and to get ready to support new hair growth).
- Transforming growth factor beta TGF-β stimulates the signaling pathways that manage the HC (Hair growth cycle). TGF-β gives structure to the hair growth cycle. It orders the new blood vessels to “barren” areas. It creates the communication network between the native and new stem cells and growth factors so “everyone is working in unison.” It orders the stem cells to get to areas where growth can occur.
- Insulin-like growth factor 1 (IGF-1) improves the migration, survival, and proliferation of hair follicle cells. It does so with the help of Insulin-like growth factor-binding protein-1 to -6 which manages the IGF-1 effect and its connection with extracellular matrix proteins (collagens) at the hair follicle level.
There are many other growth factors involved, the list above are some of the primary ones. As you can see from this list the introduction of these growth factors whether from the bone marrow stem cells or from the PRP treatment alone, stimulates native stem cells and native growth factors to “reboot,” the hair growth mechanism.
The loss of stem cells is the loss of hair
In a January 2022 supportive study published in the journal Cell stem cell researches (2) wrote of hair shaft survival by preventing hair follicle stem cell (HFSC) loss : “In aging, androgenic alopecia, and genetic hypotrichosis (hair growth) disorders, hair shaft miniaturization (it gets smaller) is often associated with hair follicle stem cell (HFSC) loss. However, the mechanism causing this stem cell depletion in vivo (in the body) remains elusive.”
In this study the researchers show that hair shaft loss or a reduction in diameter shrinks the physical size, which results in mechanical compression of hair follicle stem cells and their apoptotic (death) loss.
Persistent hair shaft miniaturization during aging and genetic hair growth disorders causes long-term hair follicle stem cell loss. Our results identify an unconventional role of the inert hair shaft structure as a functional niche component governing hair follicle stem cell survival.
In an accompanying editorial, (3) this article’s findings were summarized as “The number of hair follicle stem cells decreases during aging and in hair-loss disorders, such as alopecia. In this (article, the researchers) discover that the hair shaft serves as a physical niche component for the preservation of hair follicle stem cells.”
This is a demonstration of hair injections. This is a PRP hair treatment. It can be considered an alternative to hair transplant surgery.
Looking further at Stem Cell-Based Treatments for Hair Loss Conditions
A 2020 paper from the University of Miami, Miller School of Medicine (4), gives us a good summary of the current research: “Novel discoveries revolving around stem-cell based therapies provide encouraging steps towards developing more effective and successful hair loss treatments. Although these initial steps towards such discoveries are hopeful, there is still a limited amount of clinical data to fully support stem-cell based therapies. . . While results are certainly hopeful, larger and more robust double blind controlled clinical trials are needed to further assess the exact mechanisms, therapeutic potential and safety of stem-cell based approaches to hair loss management.”
Limitations of treatment
An April 2023 paper, (5) while suggesting: “stem cells have the potential to enhance medical treatment options currently available for alopecia. Although these studies are in their infancy, there are over 4700 NIH (National Institutes of Health) -sponsored clinical trials underway to understand all the pathways and possible application of stem cell therapy.” But, the authors of the paper add: “Stem cell therapy for hair loss also has many limitations. The studies have not been standardized in the preparation of the cells and the quantity used. There has been no study in the time interval between treatments and whether the stem cell injection is permanent. The advantage of one type of donor stem cell such as adipose tissue versus others such as bone marrow or hair follicle has not been studied.”
1 Owczarczyk-Saczonek A, Krajewska-Włodarczyk M, Kruszewska A, Banasiak Ł, Placek W, Maksymowicz W, Wojtkiewicz J. Therapeutic potential of stem cells in follicle regeneration. Stem cells international. 2018 Oct;2018.
2 Xie Y, Chen D, Jiang K, Song L, Qian N, Du Y, Yang Y, Wang F, Chen T. Hair shaft miniaturization causes stem cell depletion through mechanosensory signals mediated by a Piezo1-calcium-TNF-α axis. Cell Stem Cell. 2022 Jan 6;29(1):70-85.
3 Hinnant T, Lechler T. Hair follicle stem cells feel the pressure. Cell Stem Cell. 2022 Jan 6;29(1):1-2. doi: 10.1016/j.stem.2021.12.001. PMID: 34995491.
4 Egger A, Tomic-Canic M, Tosti A. Advances in Stem Cell-Based Therapy for Hair Loss. CellR4 Repair Replace Regen Reprogram. 2020;8:e2894. Epub 2020 Sep 2.
5 Talebzadeh AT, Talebzadeh N. Stem Cell Applications in Human Hair Growth: A Literature Review. Cureus. 2023 Apr 11;15(4).