Novel effect of sildenafil on hair growth
Background: Sildenafil (Viagra, Kamagra Oral Jelly by Indian Manufacturer – Ajanta Pharma Limited), a phosphodiesterase 5 (PDE5) inhibitor, is known to increase the intracellular level of cyclic guanosine monophosphate (cGMP), which causes vasodilation. However, the effect of sildenafil on human hair follicles (hHFs) is unknown.
Objective: The purpose of this study was to determine the role of sildenafil in hair growth.
Methods: We investigated the expression of PDE5 in human dermal papilla cells (hDPCs) and hHFs. The effects of sildenafil on hDPC proliferation were evaluated using BrdU assays. The mRNA expression of growth factors and extracellular signal-regulated kinase (ERK) phosphorylation were investigated using real-time PCR and western blotting, respectively. Additionally, anagen induction and perifollicular vessel formation were evaluated using an in vivo mice model.
Results: We confirmed high expression of PDE5 in hDPCs and hHFs. Sildenafil enhances proliferation of hDPCs and up-regulates the mRNA expression of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), which are responsible for hair growth. Additionally, sildenafil up-regulates the levels of phosphorylated ERK and accelerates anagen induction by stimulating perifollicular vessel formation after topical application in mice.
Conclusion: Our study demonstrates for the first time, the significant therapeutic potential of sildenafil on hair growth and its potential use in treatment of alopecia.
Choi HI, Kang BM, Jang J, Hwang ST, Kwon O. Novel effect of sildenafil on hair growth. Biochem Biophys Res Commun. 2018 Nov 2;505(3):685-691. doi: 10.1016/j.bbrc.2018.09.164. Epub 2018 Oct 3. PMID: 30292404.
The use of phosphodiesterase inhibitors for the treatment of alopecia
Background: Hair loss encompasses a group of scarring and nonscarring diseases with limited treatment options. Understanding the pathogenesis of alopecias has led to the experimental use of phosphodiesterase inhibitors (PDEi).Objective: To perform a systematic review of literature surrounding the use of PDEi for alopecia.Materials and methods: A search was conducted using PubMed in February 2019 on PDEi and alopecia. Inclusion criteria were clinical trials, prospective or retrospective studies, case series and case reports written in English, using PDEi in human subjects for the treatment of alopecia.Results: Fifteen articles were included for review – eight discussing the use of topical caffeine 0.2%-2.5% for the treatment of androgenetic alopecia (AGA) and telogen effluvium (TE), one using injectable caffeine for AGA, one using topical sildenafil for pediatric alopecia areata (AA), and five using oral apremilast for adult AA.Conclusions: Preliminary results using topical caffeine for AGA or TE are promising with minimal adverse events. However, these studies are primarily single-center trials with few patients. Studies using topical or systemic PDEi for AA demonstrate limited success. Current research using PDEi for alopecia is limited, however new clinical trials are being conducted.
Juhász MLW, Atanaskova Mesinkovska N. The use of phosphodiesterase inhibitors for the treatment of alopecia. J Dermatolog Treat. 2020 May;31(3):245-253. doi: 10.1080/09546634.2019.1592097. Epub 2019 Apr 2. PMID: 30935254.
Determination of the sildenafil effect on alopecia areata in childhood
An open-pilot comparison study
Background: Alopecia areata is an immunologically mediated cessation of hair growth primarily involving, but not limited to, the scalp. The treatment of alopecia areata involves promotion of hair growth (for instance with topical minoxidil application), immunosuppression (intralesional or systemic steroid therapy, phototherapy) or immunomodulation (anthralin, dinitrochlorobenzene, diphenylcyclopropenone, squaric acid dibutylester). All these medications have some disadvantages and difficulties for the treatment of children with alopecia areata.
Objective: To use an open-pilot study to assess the efficacy of topical 1% sildenafil in children diagnosed with alopecia areata.
Methods: Eight patients with (25% of scalp surface area involvement) alopecia areata who were refractory to previous topical treatments applied 1% sildenafil twice daily for 3 months. All the patients completed the study.
Results: Two patients experienced vellus-type hair growth and one patient had terminal hair growth. However, these outcomes were accepted as the spontaneous regression of the disease.
Conclusion: We cannot recommend the use of topical 1% sildenafil for the treatment of alopecia areata without further evidence of its therapeutic benefit.
Sarifakioglu E, Degim IT, Gorpelioglu C. Determination of the sildenafil effect on alopecia areata in childhood: An open-pilot comparison study. J Dermatolog Treat. 2006;17(4):235-7. doi: 10.1080/09546630600895003. PMID: 16971319.
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