Evaluation of wavelength-dependent hair growth effects on low-level laser therapy: an experimental animal study

Enhanced Hair Regrowth Through Dual-Wavelength Low-Level Laser Therapy: A Comparative Study on Mice

Low-level laser therapy (LLLT) is a non-invasive treatment that uses low-power lasers or light sources to stimulate biological responses. Previous studies focused on single-wavelength effects on hair growth in mice. In this study, we investigated dual-wavelength combinations to enhance hair regrowth. Using light-emitting diodes (LEDs) at 670, 680, 780, and 880 nm, we assessed the correlation between different wavelength pairs and hair regrowth after shaving in mice. Phototherapy was conducted over 14 days, with results analyzed through surface image analysis and histological examination. Our findings indicate that dual-wavelength therapy is superior to single-wavelength treatment and significantly more effective than the untreated control, demonstrating its potential for improved hair regrowth.

Medical Treatment for Androgenetic Alopecia

Androgenetic alopecia is a common type of hair loss, which is generally influenced by genetic factors and systemic androgens resulting in follicular miniaturization.1 It can cause cosmetic problems leading to psychological distress among affected men and women. Effective standard medical treatments available are topical minoxidil 2 to 5%, oral finasteride, oral dutasteride, and hair transplantation.1 However, some patients do not achieve favorable results with standard treatments. For these reasons, other novel treatments have been developed, including new medications, regenerative medicines (autologous platelet-rich plasma, adipose-derived stem cells, micrograft generation, and exosome), and low-level laser therapy.

Enhanced hair growth effects through low-level vortex beams radiation: An experimental animal study

Photobiomodulation therapy (PBMT) is a non-invasive and pain-less treatment for hair loss. Researches on PBMT rarely considered the impact of different light structures. In this study, we irradiated shaven rats with both 650 nm, m = 32 vortex beams and ordinary Gaussian beams. The laser treatment was performed at 24-hour intervals for 20 days. The energy density was set to 4.25 J/cm² . The results indicated that low-level vortex beam irradiation led to better stimulation of hair growth than the Gaussian beams, which might be related to deeper penetration. The underlying biological mechanisms are discussed in terms of the activation of Wnt/β-catenin/sonic hedgehog pathway. Our results suggest that low-level vortex beam irradiation is advantageous to the treatment of hair loss because it is technically feasible, convenient and effective.

Photobiomodulation of the Visual System and Human Health

Humans express an expansive and detailed response to wavelength differences within the electromagnetic (EM) spectrum. This is most clearly manifest, and most studied, with respect to a relatively small range of electromagnetic radiation that includes the visible wavelengths with abutting ultraviolet and infrared, and mostly with respect to the visual system. Many aspects of our biology, however, respond to wavelength differences over a wide range of the EM spectrum. Further, humans are now exposed to a variety of modern lighting situations that has, effectively, increased our exposure to wavelengths that were once likely minimal (e.g., “blue” light from devices at night). This paper reviews some of those biological effects with a focus on visual function and to a lesser extent, other body systems.

Trichogenic Photostimulation Using Monolithic Flexible Vertical AlGaInP Light-Emitting Diodes

Alopecia is considered an aesthetic, psychological, and social issue among modern people. Although laser-induced skin stimulation is utilized for depilation treatment, such treatment has significant drawbacks of high energy consumption, huge equipment size, and limited usage in daily life. Here, we present a wearable photostimulator for hair-growth applications using high-performance flexible red vertical light-emitting diodes (f-VLEDs). Flexible microscale LEDs were effectively fabricated by a simple monolithic fabrication process, resulting in high light output (∼30 mW mm^-2), low forward voltage (∼2.8 V), and excellent flexibility for wearable biostimulation. Finally, trichogenic stimulation of a hairless mouse was achieved using high-performance red f-VLEDs with high thermal stability, device uniformity, and mechanical durability.

Systematic review of low-level laser therapy for adult androgenic alopecia

Alopecia is a common disorder affecting over half of the world's population. Within this condition, androgenic alopecia (AA) is the most common type, affecting 50% of males over 40 and 75% of females over 65. Anecdotal paradoxical hypertrichosis noted during laser epilation has generated interest in the possibility of using laser to stimulate hair growth. In this study, we aimed to critically appraise the application of low-level laser therapy for the treatment of AA in adults. A systematic review was performed on studies identified on Medline, EMBASE, Cochrane database, and clinicaltrials.org. Double-blinded randomized controlled trials were selected and analyzed quantitatively (meta-analysis) and qualitatively (quality of evidence, risk of bias). Low-level laser therapy appears to be a promising noninvasive treatment for AA in adults that is safe for self-administration in the home setting. Although shown to effectively stimulate hair growth when compared to sham devices, these results must be interpreted with caution. Further studies with larger samples, longer follow-up, and independent funding sources are necessary to determine the clinical effectiveness of this novel therapy.

New-Generation Therapies for the Treatment of Hair Loss in Men

Hair loss affects millions of people worldwide and can have devastating effects on an individual's psychoemotional well-being. Today hair restoration technologies through hair transplantation have advanced with the use of robots and follicular unit extraction/grafting that can offer patients excellent clinical results. Adjuvant modalities, such as platelet-rich plasma injections, lasers, and stem cells, can further enhance durability, health, and appearance of hair transplants.

Wnt/β-catenin and ERK pathway activation: A possible mechanism of photobiomodulation therapy with light-emitting diodes that regulate the proliferation of human outer root sheath cells

BACKGROUND

Outer root sheath cells (ORSCs) play important roles in maintaining hair follicle structure and provide support for the bulge area. The hair growth promoting effects of photobiomodulation therapy (PBMT) have been reported, but the mechanisms for this in human ORCs (hORSCs) have rarely been studied.

OBJECTIVE

The aim of this study was to investigate the effect of various wavelengths of light-emitting diode (LED) irradiation on human ORSCs (hORSCs).

METHODS

LED irradiation effects on hORSC proliferation and migration were examined with MTT assay, BrdU incorporation assay and migration assays. hORSCs were irradiated using four LED wavelengths (415, 525, 660, and 830 nm) with different low energy levels. LED irradiation effects on the expression of molecules associated with the Wnt/β-catenin signaling and ERK pathway, hair stem cell markers, and various growth factors and cytokines in hORSCs were examined with real-time PCR and Western blot assay. The effect of the LED-irradiated hORSCs on cell proliferation of human dermal papilla cells (hDPCs) was examined with co-culture and MTT assay.

RESULTS

PBMT with LED light variably promoted hORSC proliferation and suppressed cell apoptosis depending on energy level. LED irradiation induced Wnt5a, Axin2, and Lef1 mRNA expression and β-catenin protein expression in hORSCs. Phosphorylation of ERK, c-Jun, and p38 in hORSCs was observed after LED light irradiation, and ERK inhibitor treatment before irradiation reduced ERK and c-Jun phosphorylation. Red light-treated hORSCs showed substantial increase in IL-6, IL-8, TNF-a, IGF-1, TGF-β1, and VEGF mRNA. Light irradiation at 660 and 830 nm projected onto hORSCs accelerated in vitro migration. LED-irradiated hORSCs increased hDPCs proliferation when they were co-cultured. The conditioned medium from LED-irradiated hORSCs was sufficient to stimulate hDPCs proliferation.

CONCLUSION

These results demonstrate that LED light irradiation induced hORSC proliferation and migration and inhibited apoptosis in vitro. The growth-promoting effects of LEDs on hORSCs appear to be associated with direct stimulation of the Wnt5a/β-catenin and ERK signaling pathway. Lasers Surg. Med. 49:940-947, 2017. © 2017 Wiley Periodicals, Inc.