Progress of clinical research on fractional laser treatment of androgenetic alopecia: A review article

BACKGROUND

Androgenetic alopecia (AGA) is a prevalent form of hair loss that affects both men and women, severely impacting patients' quality of life. Traditional treatments include oral medications, topical medications, and hair transplantation, but these methods have certain side effects and limitations. How to safely effectively and maximally promote hair growth has been a key issue in the treatment of AGA. In recent years, fractionated laser therapy, as a noninvasive method, has gradually gained attention due to its minimally invasive and highly effective nature.

AIMS

In this paper, we summarized the studies related to fractional laser treatment of AGA in the past 15 years, and discussed its therapeutic mechanism, clinical effect, future development direction, and advantages and disadvantages compared with traditional treatment methods in the treatment of AGA.

METHODS

An extensive literature search was conducted using PubMed, Google, Google Scholar, Embase, and Scopus. All available articles studying fractional laser treatment of AGA were compiled in March 2024. Titles and abstracts were then screened for relevance and thoroughly examined for patient clinical outcomes. Prospective clinical trials, retrospective chart reviews, case series, and individual case reports were included in the literature review.

CONCLUSIONS

Fractional laser treatment of AGA showed remarkable efficacy and high safety. Compared with traditional treatments, fractional laser has the advantages of minimally invasive, quick recovery, fewer side effects, and a wide range of population applicability, providing an effective treatment option for AGA patients. Further large-scale clinical studies will help optimize the laser parameters and treatment settings to improve the therapeutic effect.

Investigator-blinded, controlled, and randomized comparative study on 1565 nm non-ablative fractional laser versus 5% minoxidil for treatment of androgenetic alopecia

BACKGROUND

Characterized by progressive hair loss due to an excessive response to androgens, androgenetic alopecia (AGA) affects up to 50% of males and females. Minoxidil is one of approved medications for AGA but inadequate responses occur in many patients.

AIMS

To determine whether 1565 nm non-ablative fractional laser (NAFL) could yield better therapeutic benefits for patients with AGA as compared with 5% minoxidil.

METHODS

Thirty patients with AGA were enrolled; they were randomly assigned into the laser or minoxidil treatment groups. For the laser treatment group, patients were treated by 1565 nm NAFL at 10 mJ, 250 spots/cm2 with 2 weeks intervals for 4 sessions in total. For the minoxidil treatment group, 1-milliliter of topical 5% minoxidil solution was applied to hair loss area twice a day.

RESULTS

The primary outcomes were the changes in numerous hair growth indexes at the Week 10 as compared with the baselines. Both 1565 nm NAFL and 5% minoxidil led to significantly greater hair densities and diameters in patients at the Week 10 than the baselines (p < 0.01). As compared with 5% minoxidil, 1565 nm NAFL showed significantly greater improvements in total hair number, total hair density (hair/cm2), terminal hair number, terminal hair density (hair/cm2), number of hair follicle units, and average hair number/number of hair follicle units.

CONCLUSIONS

Our data demonstrate that 1565 nm NAFL exhibits superior clinical efficacy in some aspects of hair growth to the topical minoxidil. It is a safe and effective modality in treating AGA.

Use of fractionated laser therapy for the treatment of androgenetic alopecia: a systematic review and meta-analysis

Procedural management, including fractionated laser therapy, has been increasingly investigated for the management of androgenetic alopecia (AGA). However, no comprehensive resources exist detailing the efficacy of fractionated laser therapies used for the treatment of AGA. A systematic review investigating fractionated laser use for AGA was performed, separated into each distinct fractionated laser modality. A meta-analysis was performed to examine improvement in hair counts and hair shaft diameter. Fourteen studies were included for systematic review, which identified the use of erbium-glass, thulium, erbium-ytrrium:aluminum garnet (YAG), and carbon dioxide (CO2) fractionated laser for the treatment of AGA. In the meta-analysis, fractionated laser combination therapy showed significant improvement in hair shaft diameter (2.51, 95% CI 2.37-2.65, I2 = 90.54). Fractionated laser monotherapy alone significantly improved hair shaft diameter (2.28 95% CI 2.03-2.52, I2 = 91.20%). This effect was durable on subgroup analysis for both erbium-glass (2.36 95% CI 2.01-2.71, I2 = 92.05%) and thulium (1.61 95% CI 1.08-2.15, I2 = < 0.00%). There was no improvement in hair shaft count for any laser modality. Erbium-glass laser is an effective modality as either monotherapy or combination with topical/injectable therapies to improve hair shaft diameter in AGA.

What Do We Know About Hair Growth Induced by Wounding and Its Therapeutic Applications?

BACKGROUND

Many studies have reported the role of hair follicles (HFs) in the wound healing response, and vice versa, the creation of superficial injuries may stimulate hair growth, which has encouraged new treatments for hair loss.

OBJECTIVE

To review the phenomenon of wound-induced hair growth and the usefulness of therapeutic procedures based on skin wounding in androgenetic alopecia (AGA).

METHODS

A literature search was conducted to review cases of localized hypertrichosis induced by wounds and the role of microneedling, fractional laser, and scalp threading as monotherapy for AGA.

RESULTS

Localized hypertrichosis has been extensively reported after bone fractures, burn injury, chronic venous ulcer, etc. Only 2 cases of wound-induced hair neogenesis in humans have been reported. As monotherapy for AGA, 1 of 3 studies of microneedling, 4 of 6 of fractional lasers, and 2 of 3 studies of scalp threading show good efficacy.

CONCLUSION

Certain types of wounds seem to stimulate localized hair growth in humans, but the underlying mechanism is unclear. Reports on wound-induced HF neogenesis in humans are anecdotal and questions remain as to whether this is a true phenomenon in humans. Further clinical studies are needed before recommending wound-induced hair growth procedures as therapies for AGA.

Recent Advances in Understanding of the Etiopathogenesis, Diagnosis, and Management of Hair Loss Diseases

Hair-loss diseases comprise heterogenous conditions with respective pathophysiology and clinicopathological characteristics. Major breakthroughs in hair follicle biology and immunology have led to the elucidation of etiopathogenesis of non-scarring alopecia (e.g., alopecia areata, AA) and cicatricial alopecia (e.g., lichen planopilaris, LPP). High-throughput genetic analyses revealed molecular mechanism underlying the disease susceptibility of hair loss conditions, such as androgenetic alopecia (AGA) and female pattern hair loss (FPHL). Hair loss attracted public interest during the COVID-19 pandemic. The knowledge of hair loss diseases is robustly expanding and thus requires timely updates. In this review, the diagnostic and measurement methodologies applied to hair loss diseases are updated. Of note, novel criteria and classification/scoring systems published in the last decade are reviewed, highlighting their advantages over conventional ones. Emerging diagnostic techniques are itemized with clinical pearls enabling efficient utilization. Recent advances in understanding the etiopathogenesis and management for representative hair diseases, namely AGA, FPHL, AA, and major primary cicatricial alopecia, including LPP, are comprehensively summarized, focusing on causative factors, genetic predisposition, new disease entity, and novel therapeutic options. Lastly, the association between COVID-19 and hair loss is discussed to delineate telogen effluvium as the predominating pathomechanism accounting for this sequela.

Non-ablative Er:YAG laser is an effective tool in the treatment arsenal of androgenetic alopecia

Background

Up to 70% of the adult population worldwide is affected by androgenetic alopecia (AGA) hair loss. Laser therapy offers an addition or alternative to pharmaceutical and surgical treatment of hair regrowth, with non‐ablative lasers being preferred over ablative lasers in terms of safety and downtime. Combining laser therapy with different topical agents may result in better hair regrowth.

Objective

The aim was to evaluate the effectiveness and safety of non‐ablative Er:YAG laser used in clinical practice, alone or in combination with other treatment modalities, in patients with both early and advanced stages of AGA.

Methods and patients

Sixteen patients (7 male and 9 female) with active AGA in different stages were treated with the non‐ablative Er:YAG laser (SMOOTH^TM mode, 7 mm spot size, 7.00 J/cm² pulse fluence, 3.3 Hz frequency) as a monotherapy or in combination with injections of platelet‐rich plasma (PRP) to the scalp, topical minoxidil, and oral supplements for the promotion and support of hair growth. Efficacy was assessed with clinical assessment of AGA grade (Ludwig scale for female / Norwood‐Hamilton scale for male) and with blind evaluation of hair quality in global photographs before and after treatment. Patients subjectively rated their satisfaction with the laser treatment on a scale from 0–3 and pain on a VAS scale from 0–10.

Results

AGA grade after treatment was lower compared to baseline (p = 0.015 and p = 0.125 in female and male patients, respectively). Blind evaluation indicated an improvement in hair quality in 93% of patients, either being described as much better (14%) or as better (79%), which was not correlated with age or AGA grade. The median satisfaction score was 3, and the median VAS score for pain was 2. The positive effect of the treatment on the hair quality is ongoing. No adverse reactions were reported.

Conclusions

The treatment was effective in treating AGA, confirmed by a decrease in AGA grade and by blinded evaluation of global photographs. Although the possible additive or complementary effect of topical minoxidil or nutraceuticals cannot be excluded, our results suggest that the non‐ablative Er:YAG laser SMOOTH^™ mode as a monotherapy, or in combination with PRP, is an efficient and safe treatment for AGA—with a high satisfaction rate among patients regardless of patient age, AGA duration, or AGA stage.

Non-thermal plasma promotes hair growth by improving the inter-follicular macroenvironment

Non-thermal plasma (NTP) is widely used in the disinfection and surface modification of biomaterials. NTP treatment can regenerate and improve skin function; however, its effectiveness on hair follicle (HF) growth and its underlying mechanisms need to be elucidated. Herein, we propose an air-based NTP treatment, which generates exogenous nitric oxide (eNO), as a therapeutic strategy for hair growth. The topical application of air-based NTP generates large amounts of eNO, which can be directly detected using a microelectrode NO sensor, in the dermis of mouse dorsal skin. Additionally, NTP-induced eNO has no cytotoxicity in normal human skin cells and promotes hair growth by increasing capillary tube formation, cellular proliferation, and hair/angiogenesis-related protein expression. Furthermore, NTP treatment promotes hair growth with adipogenesis and activation of CD34⁺CD44⁺ stem cells and improves the inter-follicular macroenvironment via increased perifollicular vascularity in the mouse hair regrowth model. Given the importance of the hair follicle (HF) cycle ratio (growth vs. regression vs. resting) in diagnosing alopecia, NTP treatment upregulates the stem cell activity of the HF to promote the anagen : catagen : telogen ratio, leading to improved hair growth. We confirmed the upregulation of increasing Wnt/β-catenin signaling and activation of perifollicular adipose tissue and angiogenesis in HF regeneration. In conclusion, these results show that the eNO from NTP enhances the cellular activities of human skin cells and endothelial cells in vitro and stem cells in vivo, thereby increasing angiogenesis, adipogenesis, and hair growth in the skin dermis. Furthermore, the results of this study suggest that NTP treatment may be a highly efficient alternative in regenerative medicine for achieving enhanced hair growth.

Non-thermal plasma (NTP) is widely used in the disinfection and surface modification of biomaterials.

Energy-based Devices for Hair Loss

Treatment options for hair loss have traditionally been limited to topical and systemic therapies. Systemic therapies for inflammatory hair disorders are often immunosuppressive, and systemic treatment of androgenetic hair loss can cause undesired effects on sexual and reproductive health. Topical agents have a favorable side effect profile compared with systemic therapies, but many topicals have poor transcutaneous absorption, limiting their concentration and action at follicular targets in the dermis.

Female Pattern Hair Loss-An Update

Female pattern hair loss (FPHL) is nonscarring progressive thinning of hair with gradual decrease in the number of hair, especially in the frontal, central, and parietal scalp, due to a process known as follicular miniaturization. The etiopathogenesis of FPHL is complex with multiple factors such as genetics, inflammation, hormones, and environment playing role in it. It usually manifests as slowly progressive hair thinning, mainly over the vertex and upper parietal scalp, the frontal hairline is often spared and the miniaturization is also not as severe as in men. A thorough history, clinical examination, hair loss evaluation tests, dermoscopy, and scalp biopsy can help in establishing the diagnosis. Various biochemical tests may be needed in patients with hyperandrogenism. The treatment includes medical and surgical modalities. Topical minoxidil is still considered the first line of treatment. Along with medical therapy, cosmetic camouflage may also be needed in some cases.

Finasteride and Its Potential for the Treatment of Female Pattern Hair Loss: Evidence to Date

The currently approved treatment for female pattern hair loss (FPHL) includes topical minoxidil administration; however, this treatment fails to achieve hair regrowth in some patients. Finasteride, a selective 5α-reductase inhibitor (5-ARI), may be considered as an alternative treatment. However, because of its potential teratogenic effects, clinical studies and use of finasteride for FPHL are limited. In this review, we aim to summarize the literature regarding the pharmacology, clinical efficacy, and adverse effects of oral finasteride for the treatment of FPHL and to provide novel therapeutic options including topical finasteride and dutasteride, a new generation 5-ARI, for the treatment of FPHL.

Laser-assisted Hair Regrowth: Fractional Laser Modalities for the Treatment of Androgenic Alopecia

Background:

A large proportion of the population is at sometime affected by androgenic alopecia. Current therapies consisting of minoxidil or finasteride are often the first choices for treatment. These regimens are limited by their efficacy, side-effect profiles, and often lengthy treatment courses. Low level laser/light has shown to be relatively effective and safe for the treatment of hair loss, and a number of products are currently available to consumers. Recently, fractional lasers have been examined as treatment options for androgenic alopecia. The mechanism of action of these minimally invasive resurfacing procedures is thought to be 2-fold. First, the microscopic injuries created by these treatments may induce a favorable wound healing environment that triggers hair growth. Alternatively, disruption of the stratum corneum allows for improved transdermal passage of well-established therapeutic drugs to the hair roots.

Methods:

A literature review was performed to evaluate the efficacy of these emerging treatments on hair regrowth.

Results:

Nine original studies examining the effect of fractional lasers on hair growth in androgenic alopecia have been reviewed.

Conclusions:

Preliminary evidence suggests that fractional laser therapies have a positive effect on hair regrowth; however, most of the literature is limited to case reports, and small prospective and retrospective series. Further studies, in the form of well-designed randomized controlled trials, are necessary to evaluate the efficacy, safety, and optimal treatment courses.

The Effect of the Fractional Carbon Dioxide Laser on Improving Minoxidil Delivery for the Treatment of Androgenetic Alopecia

Introduction: Recently, laser treatment for hair loss has become very popular. Laser-assisted drug delivery (LAD) is an evolving technology with potentially broad clinical applications. This work aims at inspecting the effect of the fractional carbon dioxide laser (CO₂ ) on improving the delivery of minoxidil in patients with androgenetic alopecia and detecting the role of the fractional CO₂ laser in its treatment. Methods: We enrolled 45 Egyptians with male androgenetic alopecia (MAGA); clinical grading was assessed based on Norwood-Hamilton classification. The patients were divided into 3 groups: the first group (combined group) received the fractional CO₂ laser session followed by topical application of minoxidil and also in between sessions; the second group received fractional CO₂ laser sessions only and 6 sessions with 2-week intervals were performed; the third group applied topical minoxidil only for 3 months. Global photographs and dermoscopic assessments were performed before treatment and 3 months after the treatment. Results: Several dermoscopic findings were detected, including peripilar sign, hair diversity, yellow spot, white dots, and arborizing red lines. The number of double hair units significantly increased after the treatment in the combined group. The mean number of hair after the treatment in the 3 groups significantly increased, mostly in the combined group. The hair thickness (thin & thick) significantly increased after the treatment in the combined group and the fractional group; however, in the minoxidil group, only thin hair thickness increased. In all the 3 groups, there was a significant improvement in hair count and thickness. Conclusion: The ablative fractional CO₂ laser alone or combined with minoxidil may serve as an additional treatment for MAGA.

The rise of transcutaneous drug delivery for the management of alopecia: a review of existing literature and an eye towards the future

Introduction: Fractional lasers and microneedling devices are increasingly used with topical drugs to treat various conditions, including alopecia, as they grant access to dermal structures such as hair follicles and cutaneous vasculature. Objective: To perform a comprehensive review on transcutaneous drug delivery for the management of alopecia. Methods: PubMed, Embase, and Ovid Medline databases were searched using terms including: alopecia, microneedling, lasers, androgenetic alopecia (AGA), alopecia areata (AA), drug delivery. Articles were examined for inclusion criteria: diagnosis of alopecia regardless of type, use of fractional laser or microneedling devices, and subsequent administration of topical medication. Results: 8 studies, 6 prospective clinical trials and 2 case series, examining either AA or AGA were identified. For AA, five studies examined microneedling together with topical triamcinolone in three of these, while two studies used photodynamic therapy. Regarding AGA, two studies used topical minoxidil plus microneedling, and one examined topical finasteride with fractional erbium glass laser. Improvement was seen in 6 of the 8 studies. Discussion: Transcutaneous drug delivery via fractional laser and microneedling is a promising modality with preliminary evidence for increased hair regrowth over topical therapy alone. Further studies are needed to elucidate treatment parameters and appropriate device selection for drug delivery.

Fractional Carbon Dioxide Laser in Combination with Topical Corticosteroid Application in Resistant Alopecia Areata: A Case Series

Introduction:

Intradermal steroid injections are used as treatment option in resistant alopecia areata. However, it is difficult and quite painful to treat large areas of alopecia with this modality.

Objective:

To assess the efficacy and safety profile of a combination of fractional carbon dioxide (CO₂) treatment followed by topical corticosteroid application in resistant alopecia areata.

Materials and Methods:

Ten cases of resistant alopecia areata who had not responded to multiple treatment modalities were treated with fractional CO₂ laser followed by topical application of triamcinolone spray (10mg/mL) on the resistant lesions. Patients received 4–8 sessions that were repeated at an interval of 3–4 weeks. Response to treatment was assessed on a quartile physician assessment scale and labeled as excellent (>75% regrowth), good (50%–75% regrowth), fair (26%–50% response), and poor (<25% regrowth).

Results:

Eight of these ten cases completed the treatment process. Seven of these eight patients had complete recovery of the area treated. One patient however did not show good response even after four sessions. No significant adverse effects were noted in any of the patients.

Conclusion:

Fractional CO₂ laser in combination with topical triamcinolone can prove to be an effective treatment option in resistant alopecia areata.

Fractional carbon dioxide laser for the treatment of facial atrophic acne scars: prospective clinical trial with short and long-term evaluation

The aim of this study was to evaluate the efficacy and safety of fractional carbon dioxide laser for the treatment of acne scars. Thirty-one participants, 15 female and 16 male, whose mean age was 34.84 ± 10.94 years, were included in this prospective study. The study took place between 2012 and 2016. Participants were evaluated with the "ECCA Grading Scale" before the first session, 3 months (short-term evaluation) and 3 years after the last session (long-term evaluation). Participants received two or three treatment sessions at 4-week intervals, with a 10,600 nm fractional carbon dioxide laser with pulse energies ranging between 100 and 160 mJ, 120 spot type, 75-100 spot/cm² density, and 30 W power. Self-assessments by the participants were done 3 months and 3 years after the last session. The mean ECCA score was 107.90 ± 39.38 before the first session, and 82.17 ± 36.23 at the time of short-term evaluation (p = 0.000). The grade of improvement at the short-term evaluation was as follows: no improvement, mild, moderate, and significant improvement for 7 (22.6%), 11 (35.5%), 9 (29%), and 4 (12.9%) of the participants, respectively. Regarding self-assessments, 80.6 and 61.3% of the participants rated themselves as having at least mild improvement at the short-term and the long-term follow-up periods, respectively. The results of this study suggest that fractional carbon dioxide laser is an efficient treatment option for acne scars. Furthermore, self-assessment results show that more than half of the participants still experience at least mild improvement at the end of 3 years.

Efficacy of fractional lasers in treating alopecia: a literature review

Hair loss stemming from different types of alopecia, such as androgenic alopecia and alopecia areata, negatively affects over half the population and, in many circumstances, causes serious psychosocial distress. Current treatment options for alopecia, such as minoxidil, anthralin, and intralesional corticosteroids, vary efficacy and side effect profiles. It is known that low-level laser/light therapies (LLLT), or photobiomodulations, such as the US FDA-cleared HairMax Lasercomb®, He-Ne laser, and excimer laser, are relatively affordable, user-friendly, safe, and effective forms of treatment for hair loss. While less is known about the effectiveness of fractional lasers for combating hair loss, research suggests that by creating microscopic thermal injury zones, fractional lasers may cause an increase in hair growth from a wound healing process, making them potential therapeutic options for alopecia. A literature review was performed to evaluate the effectiveness of fractional lasers on hair regrowth. The specific fractional laser therapies include the 1550-nm nonablative fractional erbium-glass laser, the ablative fractional 2940-nm erbium:YAG laser, and the ablative fractional CO₂ fractional laser. Additional randomized controlled trials are necessary to further evaluate the effectiveness of the lasers, as well as to establish appropriate parameters and treatment intervals.

Androgenetic Alopecia: An Update of Treatment Options

Androgenetic alopecia (AGA) is characterized by a non-scarring progressive miniaturization of the hair follicle in predisposed men and women with a pattern distribution. Although AGA is a very prevalent condition, approved therapeutic options are limited. This article discusses the current treatment alternatives including their efficacy, safety profile, and quality of evidence. Finasteride and minoxidil for male androgenetic alopecia and minoxidil for female androgenetic alopecia still are the therapeutic options with the highest level evidence. The role of antiandrogens for female patients, the importance of adjuvant therapies, as well as new drugs and procedures are also addressed.

Alopecia areata: What's new in epidemiology, pathogenesis, diagnosis, and therapeutic options?

Alopecia areata (AA) is a common and stressful disorder that results in hair loss, and resistant to treatment in some cases. Experimental and clinical evidence suggests that AA is caused by autoimmune attack against the hair follicles. The precise pathomechanism, however, remains unknown. Here, we focus on the recent progress in multidisciplinary approaches to the epidemiology, pathogenesis, and new treatments of AA in 996 publications from January 2010 to July 2016, and provide an overview of the current understanding in clinical management and research directions.

Fractional resurfacing in the Asian patient: Current state of the art

BACKGROUND AND OBJECTIVE

Fractionated photothermolysis (FP) has revolutionized modern laser technology. By creating selective columns of microthermal damage, fractionated devices allows for greater treatment depths to be achieved without the prolonged downtime and risk of complications seen in traditional fully ablative laser resurfacing. Fractional resurfacing is a proven method to treat a variety of cutaneous conditions. In the Caucasian patient, a wide range of devices and treatment settings can be utilized safely and effectively. However, ethnic skin requires special consideration due to its unique pigmentary characteristics and clinical presentations. In this review article, we detail the current indications and strategies to optimize results and mitigate complications when utilizing fractional resurfacing for the Asian patient.

METHODS

A review of the MEDLINE English literature was conducted on fractionated laser devices studied in the Asian population. Articles included describe non-ablative devices including fractionated erbium glass, thulium fiber, diode, and radiofrequency devices; and ablative devices including fractionated carbon dioxide (CO₂ ) laser, erbium yttrium aluminum garnet and yttrium scandium gallium garnet (YSGG) laser. These data were integrated with the expert opinion of the authors.

CONCLUSION

Taking into account the unique characteristics and cosmetic concerns of the Asian population, fractional resurfacing can be considered a safe and effective option for the treatment of atrophic and hypertrophic scarring, and photorejuvenation in ethnic skin types. Select cases of melasma may be treated with fractionated non-ablative devices, but utilized with caution. The predominant complication associated with fractional resurfacing for these conditions is post-inflammatory hyperpigmentation (PIH) and rebound worsening of melasma. A greater number of treatments at lower density settings and wider treatment intervals typically produce the lowest risks of PIH without compromising treatment efficacy. Lasers Surg. Med. 49:45-59, 2017. © 2016 Wiley Periodicals, Inc.

Effects of non-ablative fractional erbium glass laser treatment on gene regulation in human three-dimensional skin models

Clinical experiences with non-ablative fractional erbium glass laser therapy have demonstrated promising results for dermal remodelling and for the indications of striae, surgical scars and acne scars. So far, molecular effects on human skin following treatment with these laser systems have not been elucidated. Our aim was to investigate laser-induced effects on skin morphology and to analyse molecular effects on gene regulation. Therefore, human three-dimensional (3D) organotypic skin models were irradiated with non-ablative fractional erbium glass laser systems enabling qRT-PCR, microarray and histological studies at same and different time points. A decreased mRNA expression of matrix metalloproteinases (MMPs) 3 and 9 was observed 3 days after treatment. MMP3 also remained downregulated on protein level, whereas the expression of other MMPs like MMP9 was recovered or even upregulated 5 days after irradiation. Inflammatory gene regulatory responses measured by the expression of chemokine (C-X-C motif) ligands (CXCL1, 2, 5, 6) and interleukin expression (IL8) were predominantly reduced. Epidermal differentiation markers such as loricrin, filaggrin-1 and filaggrin-2 were upregulated by both tested laser optics, indicating a potential epidermal involvement. These effects were also shown on protein level in the immunofluorescence analysis. This novel standardised laser-treated human 3D skin model proves useful for monitoring time-dependent ex vivo effects of various laser systems on gene expression and human skin morphology. Our study reveals erbium glass laser-induced regulations of MMP and interleukin expression. We speculate that these alterations on gene expression level could play a role for dermal remodelling, anti-inflammatory effects and increased epidermal differentiation. Our finding may have implications for further understanding of the molecular mechanism of erbium glass laser-induced effects on human skin.

Hair regrowth through wound healing process after ablative fractional laser treatment in a murine model

BACKGROUND AND OBJECTIVE

Alopecia is one of the most common dermatological problems in the elderly; however, current therapies for it are limited by low efficacy and undesirable side effects. Although clinical reports on fractional laser treatment for various alopecia types are increasing, the exact mechanism remains to be clarified. The purposes of this study were to demonstrate the effect of ablative fractional laser treatment on hair follicle regrowth in vivo and investigate the molecular mechanism after laser treatment.

MATERIALS AND METHODS

Ablative CO2 fractional laser was applied to the shaved dorsal skin of 7-week-old C57BL/6 mice whose hair was in the telogen stage. After 12 mice were treated at various energy (10-40 mJ/spot) and density (100-400 spots/cm(2) ) settings to determine the proper dosage for maximal effect. Six mice were then treated at the decided dosage and skin specimens were sequentially obtained by excision biopsy from the dorsal aspect of each mouse. Tissue samples were used for the immunohistochemistry and reverse transcription polymerase chain reaction assays to examine hair follicle status and their related molecules.

RESULTS

The most effective dosage was the 10 mJ/spot and 300 spots/cm(2) setting. The anagen conversion of hair was observed in the histopathological examination, while Wnt/β-catenin expression was associated with hair regrowth in the immunohistochemistry and molecular studies.

CONCLUSIONS

Ablative fractional lasers appear to be effective for inducing hair regrowth via activation of the Wnt/β-catenin pathway in vivo. Our findings indicate that fractional laser treatment can potentially be developed as new treatment options for stimulating hair regrowth.

Drug discovery for alopecia: gone today, hair tomorrow

INTRODUCTION

Hair loss or alopecia affects the majority of the population at some time in their life, and increasingly, sufferers are demanding treatment. Three main types of alopecia (androgenic [AGA], areata [AA] and chemotherapy-induced [CIA]) are very different, and have their own laboratory models and separate drug-discovery efforts.

AREAS COVERED

In this article, the authors review the biology of hair, hair follicle (HF) cycling, stem cells and signaling pathways. AGA, due to dihydrotesterone, is treated by 5-α reductase inhibitors, androgen receptor blockers and ATP-sensitive potassium channel-openers. AA, which involves attack by CD8(+)NK group 2D-positive (NKG2D(+)) T cells, is treated with immunosuppressives, biologics and JAK inhibitors. Meanwhile, CIA is treated by apoptosis inhibitors, cytokines and topical immunotherapy.

EXPERT OPINION

The desire to treat alopecia with an easy topical preparation is expected to grow with time, particularly with an increasing aging population. The discovery of epidermal stem cells in the HF has given new life to the search for a cure for baldness. Drug discovery efforts are being increasingly centered on these stem cells, boosting the hair cycle and reversing miniaturization of HF. Better understanding of the molecular mechanisms underlying the immune attack in AA will yield new drugs. New discoveries in HF neogenesis and low-level light therapy will undoubtedly have a role to play.

Histologic comparison of microscopic treatment zones induced by fractional lasers and radiofrequency

INTRODUCTION

Fractional photothermolysis induces microscopic, localized thermal injury in the skin surrounded by undamaged viable tissue in order to promote wound healing.

OBJECTIVE

This study evaluated acute histologic changes following each single pass of various fractional lasers and radiofrequency (RF).

METHODS

Three male domestic swine were used. We used fractional Erbium:glass (Er:glass), Erbium:yttrium-aluminum-garnet (Er:YAG), CO2 lasers, and fractional ablative microplasma RF. We analyzed features and average values of the diameter, depth, and vertical sectional areas treated with each kind of laser and RF.

RESULTS

The microscopic treatment zone (MTZ) of fractional Er:glass resulted in separation of dermoepidermal junction with no ablative zone. Fractional Er:YAG provided the most superficial and broad MTZ with little thermal collateral damage. Fractional CO2 resulted in a narrow and deep "cone"-like MTZ. Fractional RF resulted in a superficial and broad "crater"-like MTZ.

CONCLUSIONS

This study provides the first comparison of MTZs induced by various fractional lasers and RF. These data provide basic information on proper laser and RF options. We think that these findings could be a good reference for information about fractional laser-assisted drug delivery.