The 730 nm picosecond titanium sapphire laser for treatment of café-au-lait macules in all skin types.

OBJECTIVES: Café-au-lait macules (CALM) are benign birthmarks presenting as uniformly pigmented, well demarcated, brown patches that can be distressing to patients, especially when located in cosmetically sensitive areas. As with all pigmentary lesions in skin of color patients, CALMs have been particularly challenging to treat. Here we present the first case series characterizing treatment parameters and clinical outcomes utilizing the 730-nm picosecond titanium sapphire laser for the treatment of CALMs. This device provides an additional safe and effective treatment option for these challenging cases. METHODS: We performed a retrospective review of patients treated at a single institution between April 2021 and December 2023. Clinical photographs were graded by 3 outside board-certified dermatologists using a 5-point visual analog scale. RESULTS: Fourteen patients (age range: 10 months-66 years, mean age: 27.4 years, Fitzpatrick skin types II-VI) were treated for CALM on the face (11) or body (3). On average, patients received 4.3 treatments, with treatment intervals ranging from 4 to 40 weeks. Treatment remains ongoing with the 730-nm picosecond laser for eight patients. Overall, patients were rated to have a mean improvement of 26%-50%. Two patients (FST III and VI) achieved 100% clearance after 4-5 treatment sessions. Our study included four patients whose CALM were of the smooth bordered "coast of California" subtype, three of whom had a mean improvement rating of only 1%-25%. The fourth patient had near complete resolution. Follow up for these patients has ranged from 6 weeks to 1.5 years. Of the patients treated, one patient experienced transient post-inflammatory hyperpigmentation and another transient post-inflammatory hypopigmentation, while a third patient experienced mild persistent guttate hypopigmentation. Three patients experienced partial recurrence indicating that maintenance treatments may be needed in some patients. CONCLUSION: The 730-nm picosecond titanium sapphire laser is a safe and efficacious treatment option, in the right morphologic setting, to improve the cosmetic appearance of CALMs in a wide range of ages and skin types. To our knowledge, this is the first reported treatment of CALMs with picosecond lasers in FST V and VI patients. Our study also supports prior studies which have found that CALM with smooth-bordered "coast of California" morphology have a poor response to laser therapy as compared to those with jagged or ill-defined bordered "coast of Maine" morphology.

Comparison of bleomycin polidocanol foam vs electrochemotherapy combined with polidocanol foam for treatment of venous malformations.

OBJECTIVE: This study aims to investigate the difference in safety and efficacy between two treatments for venous malformations (VMs), electrochemotherapy combined with polidocanol foam (ECP) and bleomycin polidocanol foam (BPF), providing alternative therapies for VMs. METHODS: We conducted a retrospective review of 152 patients with VMs treated with ECP and BPF. Pre- and post-treatment magnetic resonance images (MRIs) were collected, and clinical follow-up assessments were performed. Imaging results were used to calculate lesion volume changes. Clinical outcomes included changes in pain and improvements in perceived swelling. Patients were followed up at 1 week and 6 months after surgery. All emerging complications were documented in detail. RESULTS: Of the 152 patients, 87 (57.2%) received BPF treatment, and 65 (42.8%) received ECP treatment. The most common location of VMs was the lower extremities (92/152; 60.2%), and the most common symptom was pain (108/152; 71.1%). Forty-three patients had previously undergone therapy in the BPF group (43/87; 49.4%), whereas 30 patients had received prior treatment in the ECP group (30/65; 46.2%). The study found that the percentage of lesion volume reduction in the BPF group was not significantly different from that in the ECP group (75.00% ± 17.85% vs 74.69% ± 8.48%; P = .899). ECP was more effective when the initial lesion volume was greater than 30 mL (67.66% ± 12.34% vs 73.47% ± 8.00%; P = .048). Patients treated with BPF had significantly less posttreatment pain than those treated with ECP, in different baseline lesion size. In the overall sample, pain relief was significantly higher in the BPF group than in the ECP group (4.21 ± 1.19 vs 3.57 ± 0.76; P = .002). However, there was no difference in pain relief between the two groups for the treatment of initially large VMs (4.20 ± 0.94 vs 3.70 ± 0.87; P = .113). The ECP group was significantly more likely to develop hyperpigmentation (5/87; 5.75% vs 11/65; 16.92%; P = .026) and swelling (9/87; 10.34% vs 16/65; 24.62%; P = .019) 1 week after surgery than the BPF group. CONCLUSIONS: Our study demonstrates that both BPF and ECP are effective treatments for VMs, with BPF being a safer option. ECP is a better choice for patients with the initial lesion volume greater than 30 mL, but it is more likely to lead to early swelling and hyperpigmentation.

Clinical application of 675 nm laser therapy for dorsal hand skin hyperpigmentation.

BACKGROUND: Noninvasive skin rejuvenation treatment is growing in recognition to aesthetic medicine. AIM: The objective of the study was to assess the efficacy and the safety of the 675-nm laser source treatment of photodamaged hands. MATERIALS AND METHODS: The study included 21 patients (6 males and 15 females) with a mean age of 63 (± 9) years. Patients were treated with -two to three sessions of the 675-nm laser with a 1-month interval between sessions. Photos of each patient were collected at baseline, and 3 months after the last laser session. The 5-point Global Aesthetic Improvement Scale (GAIS) was recorded with their final assessment session (3 months). RESULTS: The total GAIS scores showed satisfactory results: 15 patients (71%) experienced 4 score (excellent improvement) changes and 6 patients (29%) experienced 3 score (good improvement) changes. Clinical images showed good efficacy and visible aesthetic results for the management of photodamaged skin. No serious adverse effects were recorded. CONCLUSION: This study demonstrates the safety and efficacy of for the aesthetic improvement of skin pigmentation and texture for photodamaged hands.

Skin hyperpigmentation index in melasma: A complementary method to classic scoring systems.

BACKGROUND: Due to relapsing nature of melasma with significant impact on quality of life, an objective measurement score is warranted, especially to follow-up the patients with melasma and their therapy response in a quantitative and precise manner. AIMS: To prove concordance of skin hyperpigmentation index (SHI) with well-established scores in melasma and demonstrate its superiority regarding inter-rater reliability. Development of SHI mapping for its integration in common scores. METHODS: Calculation of SHI and common melasma scores by five dermatologists. Inter-rater reliability was assessed by intraclass correlation coefficient (ICC) and concordance by Kendall correlation coefficient. RESULTS: Strong concordance of SHI with melasma area and severity index (MASI)-Darkness (0.48; 95% CI: 0.32, 0.63), melasma severity index (MSI)-Pigmentation (0.45; 95% CI: 0.26, 0.61), and melasma severity scale (MSS) (0.6; 95% CI: 0.42, 0.74). Using step function for mapping SHI into pigmentation scores showed an improvement of inter-rater reliability with a difference in (ICC of 0.22 for MASI-Darkness and 0.19 for MSI-Pigmentation), leading to an excellent agreement. CONCLUSION: Skin hyperpigmentation index could be an important additional cost-and time-conserving assessment method, to follow-up the patients with melasma undergoing brightening therapies in clinical studies, as well as in routine clinical practice. It is in strong concordance with well-established scores but superior regarding inter-rater reliability.

A retrospective study of 1064-nm Q-switched Nd:YAG laser therapy for acquired bilateral nevus of Ota-like macules.

BACKGROUND: The therapeutic efficacy of laser treatments for acquired bilateral nevus of Ota-like macules (ABNOM) varies among studies, and few studies have evaluated the factors affecting therapeutic effects. AIMS: To evaluate the efficacy and safety of 1064-nm Q-switched Nd:YAG laser (QSNYL) therapy for ABNOM and to identify the factors influencing the outcome. METHODS: A total of 110 patients with ABNOM were retrospectively evaluated and received two-to-nine treatment sessions. The effects of different factors on the therapeutic effect were analyzed on the basis of the number of treatments, age at first treatment, skin type, lesion color, affected area, number of lesion sites, and presence of concomitant melasma. RESULTS: The curative effect was positively correlated with the treatment time and negatively correlated with the increasing age at first treatment (p < 0.05). The curative effect was better in patients with skin type III than those with type IV ( p < 0.05) and in patients with a lesion area of less than 10 cm2 than those with a larger affected area (p < 0.05). Additionally, the treatment effect was poorer in patients with concomitant melasma (p < 0.05). The treatment effect was not significantly correlated with the lesion color or number of affected sites (p > 0.05). Eleven patients (10%) developed postinflammatory hyperpigmentation (PIH). CONCLUSIONS: Early and repeated QSNYL therapy achieved satisfactory results for ABNOM. The risk of PIH after laser treatment is highest among patients with older age, darker lesion color, and darker skin color. For patients with ABNOM with concurrent melasma, low-energy laser therapy is recommended to reduce the risk of melasma aggravation.

Comprehensive treatment of Cronkhite-Canada syndrome: A case report and literature review.

INTRODUCTION: Cronkhite-Canada syndrome (CCS) is currently considered to be a non-hereditary disease, which is relatively rare clinically. It is also known as polyposis hyperpigmentation alopecia nail dystrophy syndrome, it is a syndrome characterized by gastrointestinal polyposis and ectodermal changes, the main manifestations are gastrointestinal symptoms, skin pigmentation, alopecia, and hypothyroidism. CASE PRESENTATION: In this paper, the clinical characteristics, diagnosis and treatment of a case of CCS admitted to Huanghe Sanmenxia Hospital were analyzed. In the course of treatment, traditional Chinese medicine was used, but no hormone, and the patient's clinical symptoms were greatly relieved. CONCLUSIONS: CCS is rare, there is no specific treatment, and traditional Chinese medicine may can greatly relieve the clinical symptoms of patients. However, it's still having to be verified by a large sample, multi-center, long-term treatment follow-up studies.

Treatment of facial pigmented disorders with a 785-nm picosecond Ti:sapphire laser in Asians: A report of three cases.

Since the advent of the theory of selective photothermolysis, the importance of targeting the chromophore and minimizing the surrounding damage has been extensively discussed. Picosecond-domain laser (ps-laser) treatment with a wide range of wavelengths is an emerging option for various pigmented lesions; however, no definitive treatment choice has been confirmed. The authors aimed to investigate the efficacy and safety of a ps-laser with a 785-nm wavelength for the treatment of facial pigmented lesions in Asians. Three Korean patients with facial pigmented lesions were recruited for the study. A 785-nm ps-laser with a fractionated and an unfractionated handpiece was utilized to administer the treatment. The clinical outcome was evaluated by a clinician by comparing pre- and post-treatment photographs. All patients exhibited a significant improvement in pigmented lesions including freckles, lentigines, and melasma, after three to four sessions of treatment. No adverse events, including post-inflammatory hyperpigmentation or hypopigmentation were observed. In conclusion, this novel 785-nm Ti:sapphire ps-laser may be an effective and safe modality for treating pigmented lesions in skin of color.

Comparison of the safety and efficacy of low fluence Q-switched 1064-nm and conventional Q-Switched 755-nm lasers in the treatment of café-au-lait macules: A prospective self-controlled trial.

BACKGROUND: Conventional high fluence Q-switched (HFQS) Alexandrite 755-nm are widely used in clinical café-au-lait macules (CALMs) treatment. There have been recent concerns regarding the efficacy and safety of low fluence Q-switched (LFQS) Nd: YAG 1064-nm lasers. OBJECTIVE: To evaluate the efficacy and safety of the conventional HFQS and LFQS laser in the treatment of CALMs. METHODS: Within 3 months, 20 patients underwent prospective self-controlled split-lesion treatments with HFQS once or twice depending on the recovery rate, and with LFQS six times biweekly. Then the more effective laser was selected for continued treatments. Efficacy outcomes were evaluated by a visual analog scale (VAS) biweekly during the comparative trail. Recovery process, side effects and recurrence were recorded during the trial and follow-up visit. Patient and physician preferences for laser selection were also recorded. RESULTS: The average VAS scores of areas treated with HFQS and LFQS were 2.92 ± 0.86 and 2.93 ± 1.13, respectively (p > 0.05). The most significant efficacy change of LFQS was after the fourth laser treatment (VAS score: 1.82-2.37, p < 0.001). 11 lesions treated with LFQS and 7 with HFQS achieved an optimal treatment response (3.67 ≤ VAS ≤ 4). Three patients relapsed on one side (one on LFQS, two on HFQS) and five on both sides. Adverse effects included temporary hypopigmentation, hyperpigmentation, uneven pigmentation, and mottled hypopigmentation. Doctors thought 80% of patients were suitable for LFQS. 70% of patients preferred LFQS posttreatment. CONCLUSIONS: The efficacy difference between the LFQS 1064-nm laser and HFQS 755-nm laser in treating CALMs in a 3-month comparative trial was statistically insignificant. LFQS is preferred by doctors and patients and is likely to help more patients achieve treatment efficacy than the HFQS within a short time, with fewer temporary adverse reactions, and a more even pigmentation. But it can cause mottled hypopigmentation. The LFQS had obvious lesion clearance after the fourth treatment.

Q-Switched Laser Combined with Intense Pulsed Laser in the Treatment of Melasma Based on Reflection Confocal Microscope.

Chloasma is a prevalent clinical hyperpigmentation skin disorder that causes symmetrical brown to tan patches on the cheeks, as well as the neck and forearms on rare occasions. The pathophysiology of this condition is complicated, and there is now no cure. Under the light microscope, the full-thickness melanin of the epidermis in the skin lesions was increased, and the dermal chromophages increased. At present, the treatment of melasma mainly includes topical drugs, chemical peels, systemic drugs, laser therapy, and traditional Chinese medicine. With the development of medical technology, intense pulsed light and Q-switched laser have been widely used in the treatment of melasma, which can emit laser beams to penetrate the dermis uniformly to treat deep pigmented lesions in the dermis. After a stable treatment outcome for melasma is achieved, it is important to minimize side effects such as postinflammatory hyperpigmentation and skin irritation. Therefore, this paper uses a reflection confocal microscope to establish an evaluation index system and then uses a neural network to evaluate the treatment effect. The work of this paper is as follows: (1) this paper introduces various methods of treating melasma at home and abroad and focuses on the application of intense pulsed light therapy and low-energy Q-switched Nd: YAG laser in the treatment of melasma. (2) In this paper, the case data samples are trained with the designed BP network to obtain a reliable evaluation network model. (3) The results and mistakes of the evaluation are produced by training the genetic algorithm optimized backpropagation (GA-BP) network structure model to evaluate the treatment effect of chloasma. Finally, it has been demonstrated that the GA-BP network has great accuracy and stability.

Single and combined 1064 nm Q-switched Nd: YAG laser therapy in melasma: A meta-analysis.

PURPOSE: This article attempted to describe the efficacy and safety of 1064QNYL in combination with other treatments for refractory melasma. METHODS: Two researchers independently retrieved randomized controlled trials (RCTs) according to inclusion and exclusion criteria. Primary outcome was evaluated with MASI and mMASI scores in control group and experiment group. The secondary outcome was evaluated with MI scores. We calculated 95% CI of standardized mean difference (SMD) and heterogeneity of the included literature by Higgins I2 test, and assessed publication bias by Funnel plots, Egger's, and Begg's tests. RESULTS: A total of 12 articles including 322 subjects were analyzed. Experiment group was treated with 1064QNYL combined with single treatment (e.g., PDL, IPL, RF, and TA). Control group was treated with 1064QNYL alone. A greater reduction of Melasma Area and Severity Index (MASI)/modified Melasma Area and Severity Index (mMASI) scores were shown in experiment group than that in control group at the end of the treatment (SMD, -0.37; 95% CI -0.70 to -0.04, p = 0.03, I2  = 33%). The SMD of MI scores further supported this conclusion by -0.32 (95% CI -0.63 to -0.02, p = 0.04, I2  = 27%). As for adverse events (AEs), combined treatment gave rise to more mild burning, stinging, and erythema that resolved spontaneously. Several studies reported focal purpura, punctate leukoderma, hyperpigmentation, hypopigmentation, and so on. CONCLUSION: Combined 1064QNYL treatment was better than single laser treatment, with the highest short-term benefit and long-term follow-up to maintain the effect in favor of combined treatment.

Getting to the Core of Contemporary Therapies for Post-Inflammatory Hyperpigmentation.

Post-inflammatory hyperpigmentation (PIH) is a typical complication of inflammatory dermatoses that more frequently and severely affects people with darker skin. External insults to the skin, such as burn injuries, dermatologic treatments, and intrinsic skin disorders (eg, eczema and acne), are common causes of PIH. Individuals with darker skin are prone to develop PIH, which can cause substantial psychological suffering. PIH can be prevented or alleviated. When this happens, it is essential to point out what is causing it and treat it as soon as possible to prevent inflammation and PIH from progressing. If the inflammatory symptoms go away or there is no evidence of inflammation at the time of diagnosis, PIH treatments should be evaluated. To hasten the resolution of PIH, treatment should begin as soon as possible. Treatment begins with the care of the initial inflammatory condition. Topical medications, chemical peels, laser and light-based treatment, phototherapy, and other therapeutic modalities are offered to treat PIH. Understanding the therapy options available helps the physician in choosing the best treatment for each patient. With these backgrounds, the current review aimed to discuss the epidemiology, pathogenesis, clinical presentation, and available treatment options for the PIH. J Drugs Dermatol. 2022;21(3):276-283. doi:10.36849/JDD.6485.

Laser therapy in the treatment of melasma: a systematic review and meta-analysis.

Melasma is a highly prevalent and cosmetically disfiguring pigmented skin disease. The post-treatment results are often unsatisfactory. A large number of clinical trials have tried to prove the effectiveness of the combination therapy involving laser therapy, but the results have been indeterminate. This study aimed to evaluate the effectiveness of laser treatment for melasma via a systematic review and meta-analysis. We respectively searched 4 databases and clinicaltrials.gov as of June 8, 2021. Two researchers independently searched for literature and extracted data. Study outcomes were computed by weighted mean differences (WMD). All statistical analyses were performed by the Review Manager version 5.3, STATA version 14 software at 95% confidence interval. We obtained 22 eligible studies which involved a total of 694 patients. After the heterogeneity test and sensitivity analysis, we took a subgroup meta-analysis on the before and after treatment of different laser types. We found that most lasers and laser-based combinations were associated with reduced melasma area and severity index (MASI), such as low-fluence Q-switch 1,064-nm Nd: YAG laser (QSNYL) (WMD: - 2.76; 95% CI: - 3.53 to - 1.99), fractional ablative CO2 laser (WMD: - 9.36; 95% CI: - 12.51 to - 6.21), and fractional ablative 2940-nm Er: YAG laser (WMD: - 2,72; 95% CI: - 3.94 to - 1.49). Significant decrease was seen in neither MASI score of non-ablative 1550-nm fractional laser (WMD: - 1.29; 95% CI: - 2.80 to 0.21) and picosecond laser (WMD: - 0.58; 95% CI: - 1.43 to 0.27), nor melanin index (MI) of low-fluence QSNYL treatment (WMD: 10.17; 95% CI: - 4.11 to 24.46). When using laser to treat melasma, various adverse reactions may occur, most of which will resolve quickly without subsequent treatment, such as edema, erythema, scaling, and burning sensation after treatment. However, for patients with darker skin, there are risks of postinflammatory hyperpigmentation and hypopigmentation. The laser and laser-based combination treatment for melasma could significantly reduce the MASI score, which was showed by our systematic review and meta-analysis.

Efficacy and safety of tretinoin 0.05% cream to prevent hyperpigmentation during narrowband UV-B phototherapy in patients with facial vitiligo: a randomized clinical trial.

BACKGROUND: Narrowband UV-B (NBUVB) phototherapy is the mainstay of vitiligo treatment, but hyperpigmentation is one of the limitations. Meanwhile, topical tretinoin is effective against pigmentary disorders. OBJECTIVE: To determine whether tretinoin 0.05% cream would prevent hyperpigmentation when patients with facial vitiligo underwent phototherapy. METHODS: A randomized, controlled, split-face trial was conducted. Adult patients with stable, non-segmental facial vitiligo were enrolled. The left/right sides of the face were randomly allocated to receive either topical tretinoin 0.05% cream or moisturizer twice daily. The entire face was subjected to NBUVB phototherapy twice weekly for 12 weeks. The degree of hyperpigmentation was assessed as the delta L* (brightness) value of the darkest spot in each side of the face at baseline and every 4 weeks. The degree of repigmentation was assessed. RESULTS: Twenty-five patients were enrolled; 21 completed the study. The delta L* value was significantly different between the two groups: -0.5% in the tretinoin group and -8.7% in the control group at 12 weeks (p = .002). Marked repigmentation was achieved in 15 patients of both groups. CONCLUSIONS: Tretinoin 0.05% cream prevented hyperpigmentation during NBUVB phototherapy in patients with facial vitiligo, and did not compromise the overall treatment response. TRIAL REGISTRATION: ClinicalTrials.gov NCT03933774.

Q-switched 532 nm Nd:YAG laser therapy for physiological lip hyperpigmentation: novel classification, efficacy, and safety.

BACKGROUND: Physiological lip hyperpigmentation (PLH) is a common cosmetic concern in the Middle East and Asia. It is characterized by homogeneous symmetric diffuse hyperpigmentation affecting both lips. There is no satisfactory treatment for this condition. The aim of this study is to evaluate the efficacy and safety of Q-switched (QS) 532 nm Nd:YAG laser for PLH. METHODS: A total of 30 patients with clinical diagnosis of PLH were retrospectively reviewed and included in the study. Patients underwent at least one laser treatment using QS 532 nm with a minimum follow up of six months. Laser parameters were as follows: spot size 2-3 mm, pulse duration 20 ns, fluence 2-4 J/cm2. One to three sessions were performed depending on clinical response. Two methods were used for assessment: patient satisfaction and independent physician assessment. PLH was classified as grade 1 (upper lip fully affected plus only border of lower lip), grade 2 (upper lip fully affected plus most of lower lip), and grade 3 (majority of both lips hyperpigmented). RESULTS: Excellent (>75% improvement) response was achieved in 30% of patients. Good (51-75% improvement) response was seen in 37% and 43% of patients according to patient satisfaction and independent physician assessment, respectively. Majority of patients required only one treatment session. Reactivation of herpes labialis occurred in two patients, and mottled hypopigmentation in three patients. None of the patients developed persistent hyperpigmentation or scarring. CONCLUSIONS: PLH can be effectively treated with QS 532 nm Nd:YAG laser and is well tolerated by patients.

Postinflammatory hypopigmentation: a comprehensive review of treatments.

Postinflammatory hypopigmentation is an acquired form of hypopigmentation that occurs secondary to an exogenous or endogenous insult to the skin. It can occur in all skin phototypes but is more visually apparent in skin of color. Due in part to greater attention given to its counterpart, postinflammatory hyperpigmentation, there is a dearth of literature describing this entity and treatment options remain limited. This review provides a comprehensive update on the pathogenesis, diagnostic evaluation and treatment of postinflammatory hypopigmentation, with a focus on newly reported treatment modalities.

Treatment of melasma with a low-fluence 1064 nm Q-switched Nd:YAG laser: Laser toning in Caucasian women.

BACKGROUND AND OBJECTIVES: Melasma is a common, therapeutically challenging, and very often relapsing disorder of hyperpigmentation most often observed in women. Low-fluence, multipass technique with Q-switched-mode laser-"laser toning" is broadly used to treat melasma, especially in Asia. The study aimed to evaluate the effects of a series of laser treatments with very short, nanosecond pulses in the treatment of melasma in Caucasian women. MATERIAL AND METHODS: Forty polish females with Fitzpatrick skin phototype II-III and melasma were treated with 1064 nm Q-switched neodymium:yttrium-aluminum-garnet (QSNY) laser (pulse with 5 ns; spot size, 6-8 mm; fluence, 1.7-3.2 J/cm2 ; 2-8 passes; nine treatments). Melanin index (MI), erythema index (EI) by Mexameter MX18®, the modified Melasma Area Severity Index (mMASI), and the participant's self-assessment were used to evaluate the treatment results. Twenty-one patients were subjected to a 1-year follow-up. RESULTS: Significant improvement in melasma pigmentation was observed in the mean MI and mMASI score; both were significantly reduced (p < 0.0001). Significant erythema reduction was achieved (p < 0.001). In total, 70% of participants rated the laser as a method that met their expectations for treating melasma. Clinical follow-up after one year showed that the reduced melasma effect was still maintained. Patients also noticed improved skin conditions (radiance, smoothness, brightness, hydration, regeneration). No serious adverse effects were observed. CONCLUSIONS: Low-fluence 1064 nm QSNY laser is an effective, safe, and noninvasive method with long-term results in melasma treatment. QSNY (1064 nm) improves the condition of melasma patients with erythema.

Identification of the fate and regenerative mechanism of zebrafish melanocyte progenitor cells and melanocytes after laser-induced pigment ablation.

BACKGROUND AND OBJECTIVES: Lasers are known to be the most effective treatment modality for pigmentary skin diseases. However, melanocytes and melanin pigment often recur or leave post-inflammatory hyperpigmentation after the laser procedure. Studies have reported on the role of progenitor cells in pigment cell regeneration, which can be constantly replenished through mitosis. However, the response of unpigmented melanocyte progenitor cells to laser treatment is poorly understood. In this study, we used adult zebrafish skin as the melanocyte regenerative system and examined the response of melanocyte progenitor cells to laser photothermolysis. MATERIALS AND METHODS: The two groups of adult zebrafish were irradiated with 1064 nm wavelength laser system of Q-switched neodymium:yttrium-aluminum-garnet (Nd:YAG) laser with 0.3 or 0.7 J·cm-2 . We compared the regeneration of pigment at different energy levels by measuring new melanocyte counts and pigment area. We traced and quantitatively compared the melanocyte lineage cells by immunohistochemical staining using specific markers such as sox10, mitfa, and dct during the regeneration process. Three repetitive laser ablations were also held to test the postinflammatory hyperpigmentation. RESULTS: After the laser ablation of melanocytes, most of the new melanocytes appeared between Days 5 and 10. In high-energy irradiation of 0.7 J·cm-2 , the unpigmented mitfa-expressing cells showed significant decrease (p < 0.05) and showed delay in the differentiation process of melanocyte lineage cells. After repeated laser irradiation, hyperpigmentation did not appear and the final recovery ratio of the pigmented area was 87.5% and 75.3% at the 0.3 and 0.7 J·cm-2 energy levels, respectively. CONCLUSION: We suggest that laser treatment overcoming the recurrence should be planned based on the adequate energy level targeting the melanocyte progenitor cells. High-energy irradiation may induce apoptosis of progenitor cells and delay their process of differentiation. Short-term repetitive sessions of laser therapy can reduce the pigmentation in the long-term observation.

Inhibition of melanogenesis by Aster yomena callus pellet extract in melanoma cells and patients with skin pigmentation.

Plant tissue culture holds immense potential for the production of secondary metabolites with various physiological functions. We recently established a plant tissue culture system capable of producing secondary metabolites from Aster yomena. This study aimed to uncover the mechanisms underlying the potential therapeutic effects of Aster yomena callus pellet extract (AYC-P-E) on photoaging-induced skin pigmentation. Excessive melanogenesis was induced in B16F10 melanoma cells using α-melanocyte stimulating hormone (α-MSH). The effects of AYC-P-E treatment on melanin biosynthesis inducers and melanin synthesis inhibition were assessed. Based on the results, a clinical study was conducted in subjects with skin pigmentation. AYC-P-E inhibited melanogenesis in α-MSH-treated B16F10 cells, accompanied by decreased mRNA and protein expression of melanin biosynthesis inducers, including cyclic AMP response element-binding protein (CREB), tyrosinase, microphthalmia-associated transcription factor (MITF), tyrosinase related protein-1 (TRP-1), and TRP-2. This anti-melanogenic effect was mediated by mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) and protein kinase B (AKT) phosphorylation. Treatment of subjects with skin pigmentation with AYC-P-E-containing cream formulations resulted in 3.33%, 7.06%, and 8.68% improvement in the melanin levels at 2, 4, and 8 weeks, respectively. Our findings suggest that AYC-P-E inhibits excessive melanogenesis by activating MEK/ERK and AKT signaling, potentiating its cosmetic applications in hyperpigmentation treatment.