The Future of Hair Regrowth: Part 4 – Stem Cells

Some of the most anxiously awaited treatments on the hair growth horizon are those that seek to harness the power of stem cells to regrow hair. This post will give you a brief introduction to stem cells and describe some of the research and development programs focused on developing treatments for hair loss.

Stem Cells 101

Each tissue and organ in the body is made up of cells with specialized structures and unique functions. These specialized cells are generated by a process called “differentiation”, in which immature, undifferentiated cells give rise to mature, differentiated cells that are equipped to carry out specific roles.

The most versatile type of stem cells, called embryonic stem cells (ESCs), arise in the earliest stages of development and give rise to every cell type in the body. The use of human ESCs has been a source of controversy because their isolation usually requires the destruction of an embryo.

Adult stem cells (ASCs), present in low numbers in the body throughout our lives, are capable of producing multiple cell types but are already committed to a particular developmental pathway. Examples of ASCs include hair follicle stem cells, which are responsible for the growth and maintenance of hair follicles, and hematopoietic stem cells, which give rise to the various red and white blood cells that carry oxygen throughout our bodies and protect us from infections.

Promising Research into Stem Cell-Based Treatments for Alopecia

Earlier this year, the research group of Dr. Roland Lauster at Berlin Technical University published an exciting report1 in the Journal of Biotechnology detailing a method that could lead to a stem cell-based treatment for hair loss.

Dr. Lauster's group isolated dermal papilla cells from human scalp hair follicles and cultured them using the same methods as have been used for culturing embryonic stem cells and mesenchymal stem cells. The cells first formed small clusters and approximately 13.5% of these “microfollicles” eventually began to grow hair-like fibers, as shown by light microscopy and electron microscopy in this figure from the paper.

The authors suggest that their “robust, reproducible method” is a “good jumping-off point for further work” on treating male pattern baldness or chemotherapy-induced alopecia. While the hairs produced in the study were similar to vellus (fine, peach fuzz) hairs, they suggest that “with further experimentation, it may be possible to cultivate hair of different thickness, color or texture.”

Eventually these microfollicles might be produced in large quantities from a patient's own cells and injected back into the scalp, where they could form new hair follicles and grow new hairs.

Histogen and Follica: Company Profiles

Two of the most notable commercial efforts in stem cell-directed therapies for alopecia are being spearheaded by the companies Histogen and Follica. Rather than implanting stem cells into the scalp to create new hair follicles, these companies are developing methods and formulations that would stimulate the development or activity of cells already present in the scalp.

Histogen, Inc.
Location: San Diego, CA
Background: Founded by Dr. Gail Naughton, former co-founder, President and Vice Chairman of the now liquidated human tissue engineering company Advanced Tissue Sciences, Inc.
(click here to listen to an interview with Dr. Naughton on TheBaldTruth.com)
Technology: Histogen's Hair Stimulating Complex (HSC) is a mixture of soluble protein factors such as Wnt7a, VEGF, KGF, and follistatin. These proteins are secreted by cells, called embryonic fibroblasts, which are grown in a controlled laboratory environment.
Development status: Histogen has completed a double-blind, placebo-controlled Phase 1/2 clinical trial of HSC to evaluate its safety and efficacy as an injectable for hair growth. According to the Histogen website, no adverse events were observed and HSC was found to increase hair count, hair thickness, and hair density at the 12 week endpoint with continued growth observed 12 months later.2 No Phase 3 details have been released yet.

Follica, Inc.
Location: Philadelphia, PA
Background: Founded around the pioneering research of Dr. George Cotsarelis, a professor at the University of Pennsylvania, who has been studying hair follicle stem cells for over 20 years and published an early pioneering article in the journal Cell in 1990.3
Technology: Cells in the scalp are coaxed into generating hair follicles by first wounding the target area and exposing the healing tissue to stem cell modulating factors such as Wnt pathway activators.4 The company is developing a device that would perform the wounding in a controlled fashion.
Development status: Follica's development program is still in its early stages. A recent article by Dr. Cotsarelis showed that stem cells are still present in normal numbers in the scalp of men affected by androgenic alopecia,5 suggesting that their focus may shift toward increasing the production of progenitor cells, the next cell type in the differentiation cascade. An article on Xconomy.com this year quoted the CEO as saying that clinical trials are underway outside of the U.S.

Conclusion

While stem cell therapies are exciting and may hold great potential for treating diseases and regrowing damaged tissues, they have proven difficult to commercialize: after 20 years, Geron, one of the leading developers of embryonic stem cell-based therapies for neurological diseases, has given up and shifted towards developing drugs for cancer.

Still, thousands of people who suffer from alopecia hope this promising field of research and development will eventually lead to a solution for hair loss.

Check back soon for the final installment of the Avacor® Hair Regrowth Blog’s series on The Future of Hair Regrowth to learn about some of the many novel, early-stage research programs that may lead to new treatments for hair loss in the future!

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1. Lindner G, Horland R, Wagner I, Ataç B, Lauster R. De novo formation and ultra-structural characterization of a fiber-producing human hair follicle equivalent in vitro. J Biotechnol. 2011 Mar 20;152(3):108-12. Link to PubMed

2. Histogen website. (accessed 11/16/2011) http://histogen.com/applications/hsc.htm.

3. Cotsarelis G, Sun TT, Lavker RM. Label-retaining cells reside in the bulge area of pilosebaceous unit: implications for follicular stem cells, hair cycle, and skin carcinogenesis. Cell. 1990 Jun 29;61(7):1329-37. Link to PubMed

4. Ito M, Yang Z, Andl T, Cui C, Kim N, Millar SE, Cotsarelis G. Wnt-dependent de novo hair follicle regeneration in adult mouse skin after wounding. Nature. 2007 May 17;447(7142):316-20. Link to PubMed

5. Garza LA, Yang CC, Zhao T, Blatt HB, Lee M, He H, Stanton DC, Carrasco L, Spiegel JH, Tobias JW, Cotsarelis G. Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells. J Clin Invest. 2011 Feb 1;121(2):613-22. Link to PubMed