FUTURE TRENDS
Regeneration and cloning of hair follicles represents the next step in revolutionizing hair transplantation. With an unlimited supply of hairs, there will no longer be constraints based upon the density of hairs in the donor region. Keratinocyte tubulogenesis has been induced by cultured dermal papilla cells; bone marrow- and umbilical cordderived mesenchymal stem cells were shown to be a reservoir for follicle regeneration; and epidermal wounding, with upregulation of Wnt proteins, led to hair follicle regeneration in adult mouse skin. In addition, erythropoietin has been found to promote the growth of dermal papilla cells as well as to prolong the anagen phase of cultured human hair follicles. Lastly, ongoing research utilizing a mouse model for AGA should provide insights into mechanisms of disease and therapies.
Acknowledgment
The authors wish to thank Dowling B. Stough, MD, for his contribution to this chapter in the previous editions.
Additional figures available in our eBook (see inside front cover for access code).
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Hayes V, Severi G, Eggleton S, et al. The E211 G >A
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Blanpain C, Lowry WE, Geoghegan A, et al. Self-renewal, multipotency, and the existence of two cell populations within an epithelial stem cell niche. Cell. 2004;118:635–648.2. Ito M, Kizawa K, Hamada K, Cotsarelis G. Hair follicle
-
Randolph M, Tosti A. Oral minoxidil treatment for hair androgen receptor polymorphism is associated with a decreased risk of metastatic prostate cancer and androgenetic alopecia. Cancer Epidemiol Biomarkers Prev. 2005;14:993–996.12. Prodi DA, Pirastu N, Maninchedda G, et al. EDA2R is stem cells in the lower bulge form the secondary germ, a biochemically distinct but functionally equivalent progenitor cell population, at the termination of catagen. Differentiation. 2004;72:548–557.3. Garza LA, Yang C-C, Zhao T, et al. Bald scalp in men with loss: a review of efficacy and safety. J Am Acad Dermatol. 2021;84:737–746.23. Kaufman KD, Olsen EA, Whiting D, et al. Finasteride in the treatment of men with androgenetic alopecia. J Am Acad Dermatol. 1998;39:578–589.24. Finasteride Male Pattern Hair Loss Study Group. Long- associated with androgenetic alopecia. J Invest Dermatol. 2008;128:2268–2270.13. Hillmer AM, Brockschmidt FF, Hanneken S, et al.
term (5-year) multinational experience with finasteride 1 mg in the treatment of men with androgenetic alopecia. Eur J Dermatol. 2002;12:38–49.25. Leyden J, Dunlap F, Miller B, et al. Finasteride in the
Susceptibility variants for male-pattern baldness on chromosome 20p11. Nat Genet. 2008;40:1279–1281.14. Hillmer AM, Flaquer A, Hanneken S, et al. Genome-wide androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells. J Clin Invest. 2011;121:613–622.4. Garza LA, Liu Y, Yang Z, et al. Prostaglandin D2 inhibits treatment of men with frontal male pattern hair loss. J Am Acad Dermatol. 1999;40:930–937.26. Leavitt M, Perez-Meza D, Rao NA, et al. Effects of scan and fine-mapping linkage study of androgenetic alopecia reveals a locus on chromosome 3q26. Am J Hum Genet. 2008;82:737–743.15. Chiang YZ, Tosti A, Chaudry IH, et al. Lichen planopilaris hair growth and is elevated in bald scalp of men with androgenetic alopecia. Sci Transl Med. 2012;4:126ra34.5. Ellis J, Stebbing M, Harrap S. Polymorphism of the finasteride (1 mg) on hair transplant. J Dermatol Surg. 2005;31:1268–1276.27. Camacho FM, Garcia-Hernandez MJ, Fernandez-Crehuet following hair transplantation and face lift surgery. Br J Dermatol. 2012;166:666–670.16. Olsen EA, Whiting D, Bergfeld W, et al. A multicenter, androgen receptor gene is associated with male pattern baldness. J Invest Dermatol. 2001;116:452–455.6. Hillmer A, Hanneken S, Tirzmann S, et al. Genetic
JL. Value of hormonal levels in patients with male androgenetic alopecia treated with finasteride: better response in patients under 26 years old. Br J Dermatol. 2008;158:1121–1124.28. McClellan KJ, Markham A. Finasteride: a review of its use randomized, placebo-controlled double-blind clinical trial of a novel formulation of 5% topical minoxidil topical foam vs. placebo in the treatment of androgenetic alopecia in men. J Am Acad Dermatol. 2007;57:767–774.17. Avram MR, Cole JP, Gandelman M, et al. The potential variation in the human androgen gene is the major determinant of common early onset androgenetic alopecia. Am J Hum Genet. 2005;77:140–148.7. Levy-Nissenbaum E, Bar-Natan M, Frydman M, Pras E.
Confirmation of the association between male pattern baldness and the androgen receptor gene. Eur J Dermatol. 2005;15:339–340.8. Wakisaka N, Taira Y, Ishikawa M, et al. Effectiveness of in male pattern hair loss. Drugs. 1999;57:111–126.29. D’Amico AV, Roehrborn CH. Effect of 1 mg/day finasteride on concentrations of serum prostate-specific antigen in men with androgenetic alopecia: a randomized controlled trial. Lancet Oncol. 2007;8:21–25.30. Thompson IM, Goodman PJ, Tangen CM, et al. The role of minoxidil in the hair transplantation setting. Dermatol Surg. 2002;28:894–900.18. Messenger AG, Rundegren J. Minoxidil: mechanisms of finasteride on patients with male pattern baldness who have different androgen receptor gene polymorphisms. J Investig Dermatol Symp Proc. 2005;10:293–294.9. Sinclair R, Greenland KJ, Egmond S, et al. Men with action on hair growth. Br J Dermatol. 2004;150:186–194.19. Han JH, Kwon OS, Chung JH, et al. Effect of minoxidil influence of finasteride on the development of prostate cancer. N Engl J Med. 2003;349:215–224.31. Cohen YC, Liu KS, Heyden NL, et al. Detection bias due to on proliferation and apoptosis in dermal papilla cells of human hair follicle. J Dermatol Sci. 2004;34:91–98.20. Abell E. Histologic response to topically applied
Kennedy disease have a reduced risk of androgenetic alopecia. Br J Dermatol. 2007;157:290–294.10. Sawaya ME, Shalita AR. Androgen receptor polymor- the effect of finasteride on prostate volume: a modeling approach for analysis of the Prostate Cancer Prevention Trial. J Natl Cancer Inst. 2007;99:1366–1374.32. Propecia (package insert). Whitehouse Station, NJ: Merck minoxidil. Curr Ther Res. 1984;36:1098–1106.21. Goren A, Sharma A, Dhurat R, et al. Low-dose daily phisms (CAG repeat lengths) in androgenetic alopecia, hirsutism and acne. J Cutan Med Surg. 1998;3:9–15.
aspirin reduces topical minoxidil efficacy in androgenetic alopecia patients. Dermatol Ther. 2018;31:e12741.
& Co; 2004.
When transplanting Afrocentric type 4 hair, it is important to note that the curl of the follicles and the C-shaped curve of the hairs make separation of the follicles slightly more difficult (Fig. 157.17B). Rather than using a straight blade, the blade must be bent in order to not transect the hair follicles. Also, the grafts may be slightly larger, requiring a larger bore needle (e.g. 16 gauge) to create recipient sites. Lastly, there is an increased risk of keloid or hypertrophic scar formation in patients with darker skin phototypes, more often in the donor region than in the recipient sites. Injecting triamcinolone acetonide suspension prior to donor site closure may help lessen the risk of such scar formation.