Notes from the Second Intercontinental Meeting of Hair Research Societies November 5th-7th, 1998, Washington, D.C.
It was a distinguished group of close to 400 attendees from 37 different countries that contributed to the proceedings at the Second Intercontinental Meeting of Hair Research Societies. The well-organized meeting consisted of plenary sessions, keynote lectures, poster presentations and workshops on the following subjects: the hair cycle, research methods, hair follicle pigmentation and epithelial-mesenchymal interactions. In addition, informal events during lunch or dinner were planned according to interest groups.
The plenary sessions offered the opportunity for numerous researchers to present their current work and findings and, although most of the presentations were dismayingly esoteric, it was exhilarating to realize how much basic science research is taking place into the understanding of hair growth.
There are many gems of wisdom to be gleaned from the 25 or so presentations. Many of the findings have great implications for future research and development. Here are examples:
An estradiol applied to the skin of CD-1 mice can arrest follicles in telogen and produce a profound and prolonged inhibition of hair growth whereas treatments with a pure estrogen receptor antagonist causes the hair follicle to exit telogen and enter anagen, thereby initiating hair growth. The results attest to the complexity of estrogen receptor mediated signaling in hair follicle biology.
It's conceivable that the 5 alpha-reductase inhibitors used in the treatment of hair loss in alopecia androgenetica may also favor the metabolism of testosterone to estrogens.
There is new evidence that the human hair follicle dermal tissue can induce new fibre-producing follicles when transplanted to an alternative adult skin site. There is obvious significance in the evidence that male tissue was not rejected from the female skin, suggesting that the sheath dermis is immunologically privileged.
Dermal components retain the capacity to form an active dermal papilla after prolonged periods of time (36 days) in organ culture.
Hepatocyte growth factor stimulates hair follicle growth in organ cultures and mitogenic activity of hair matrix-derived cells and the topical application of minoxidil sulfate increased the expression of some of the molecules.
The poster presentations were available for viewing during the length of the meeting and often the authors were present to discuss their findings. In total, 93 posters were displayed and the information was often interesting, if not particularly surprising or new. Here are a few summaries, which may be of interest:
Alopecia areata-like hair loss has been observed in dogs, cats, horses, cattle, non-human primates, and rodent species. As in humans, the hair loss is non-scarring and reversible. Spontaneous remission occurs in all species.
Topical minoxidil was proven effective in 36% of patients with alopecia areata after 48 weeks of therapy.
Dermal papilla cells have recently been shown to possess the characteristics of androgen target cells.
The presence of 5 alpha-reductase isoenzymes within the human dermal papilla is still unclear, because different techniques to detect these isoenzymes gave conflicting results.
Minoxidil itself is not able to induce capillary fenestrations, but that it stimulates vascular endothelial growth factor expression by anagen hair bulbs and hair papilla, and as a result indirectly increases fenestrations in follicular capillary walls.
Randomized, double-blind trials support the superior efficacy of 5% minoxidil topical solution over 2% without major safety concerns.
Hair growth is largely unaffected in psoriasis.
Interleukin-1beta has been shown to be a potent inhibitor of hair growth in vitro and may be a pivotal factor in initiation of catagen.
Potassium channel openers such as diazoxide and minoxidil may promote unwanted hair growth as a side effect. The mechanisms by which potassium channel regulators affect hair growth are unclear.
There is evidence that minoxidil may have an anti-androgenic effect on hair follicles in both the beard and scalp.
Normal scalp dermal papilla cells medium stimulated both human and rat dermal papilla suggesting that the soluble mitogenic factors were able to act across the species difference. Balding cell media had less mitogenic ability. Therefore, balding cells either secrete some growth inhibitory factor(s) or fail to produce some stimulatory factor, which may well be involved in the process of alopecia androgenetica.
Topical application of liposome-entrapped molecules has the potential to modify hair growth, prevent hair loss, and restore hair color. The targeted liposome delivery demonstrated the feasibility of hair follicle gene therapy. Future experiments will utilize small molecules, proteins, and genes entrapped in liposomes to target the hair follicle for specific hair modification.
The first keynote lecture was given by Dr. Harold Slavkin on "Toward a Molecular Understanding of Epithelial Appendage Morphogenesis: Ectodermal Dysplasia-A Case Study" and drew inspiration from the ongoing work of unraveling and analyzing the human genome and the parallel mysteries between the developing hair bud and other normal and abnormal developmental embryonic problems.
The second keynote lecture by Dr. Lawrence Pinto was entitled "Identification of the Genes Involved in Complex Biological Systems: What We Have Learned from the Genetic Molecular Analysis of Circadian Rhythms". Although technically circadian rhythms pertain to biological cycles recurring at approximately 24-hour intervals (i.e. circa diem), there is exciting research into the regulatory factors that initiate or inhibit other cyclic biological phenomenon such as the hair growth cycle on the human scalp.
Some of the most productive and exciting times were spent in informal social settings talking to erudite and learned scientists and knowing that we were on the threshold of more exciting discoveries, many of which may be directly applicable to the treatment or cure of alopecia androgenetica. In fact, there are more than 50 patent pending products that deal with hair growth promotion, anti-androgens, blockage of DHT, topical immunosuppressants, etc. Ironically, it wasn't that long ago that the patent office summarily dismissed all claims for products that 'grew hair'.
The whole field of hair research is in its infancy. Twenty years ago, the medical/scientific community didn't seriously consider the subject. In the Second Intercontinental Meeting of Hair Research Societies, new findings and new questions will prompt the search for more information and understanding of a subject that's an important part of our everyday lives. The proceedings from the meeting will be available in a future issue of the Journal of Investigative Dermatology. We'll all look forward to the Third Intercontinental Meeting of Hair Research Societies in 2001 in Tokyo. See you there.
Richard Lee, M.D.
Regrowth