Lasers in Surgery and Medicine最新文献

Objectives: Picosecond lasers are extensively utilized to treat hyperpigmentation and signs of skin aging. However, the underlying biological mechanisms remain to be elucidated. This study was performed to explore the effects and mechanisms of picosecond laser therapy on melanin clearance and skin rejuvenation in a porcine model.

Methods: A dual-wavelength (532/1064 nm) picosecond laser was applied to both pigmented and non-pigmented skin of Bama miniature pigs. For pigmentation treatment, 532 nm irradiation was delivered with 3 and 4 mm spot sizes at fluences ranging from 0.4 to 1.0 J/cm², and 1064 nm irradiation was applied with 2, 3, and 4 mm spot sizes at fluences of 1.2 to 3.0 J/cm². For rejuvenation treatment, 1064 nm irradiation (8 mm spot size, 0.4 J/cm²) was employed. Skin samples were collected immediately after treatment and at 7 and 30 days post-irradiation. Hematoxylin and eosin staining and transmission electron microscopy were used to evaluate epidermal morphology and melanosome ultrastructure. Fontana-Masson staining was performed to assess melanin distribution and content, combined with CD163 immunofluorescence to visualize the colocalization of melanin and macrophages. Immunohistochemistry and Western blot analyses were conducted to determine tyrosinase expression levels. Multiplex immunohistochemistry was further applied to detect melanocytic markers (SOX10, MART-1), collagen I/III, growth factors (TGF-β1, GDF11), and barrier-related proteins (filaggrin, claudins).

Results: Picosecond laser treatment immediately induced epidermal vacuolization and melanosome disruption, followed by a progressive reduction in epidermal melanin over time, which was more prominent in the 532 nm treatment group compared with 1064 nm. Fontana-Masson and immunofluorescence staining revealed abundant CD163-positive macrophages colocalized with melanin in the dermis on Day 7, indicating active phagocytosis of pigment debris. SOX10- and MART-1-positive melanocytes were rare at Day 0 and absent thereafter in laser-treated skin. Western blot analysis showed that tyrosinase expression was significantly downregulated from Day 7 and remained suppressed through Day 30, suggesting inhibition of melanogenesis. Regarding rejuvenation, dermal collagen I and III slightly decreased at Day 7 but markedly increased by Day 30. TGF-β1 and GDF11 were upregulated following treatment. Filaggrin and claudins increased at Day 7 and declined at Day 30 but remained above baseline, indicating improved barrier integrity.

Conclusions: Picosecond lasers effectively induced pigment reduction, immune-mediated clearance and melanogenesis inhibition, while concomitantly promoting dermal regeneration and epidermal barrier repair. These findings provide mechanistic insights into their therapeutic applications in pigmentation disorders and skin aging.

Objectives: Retinal pigment epithelium (RPE) melanin absorbs laser energy during retinal laser therapy, potentially influencing treatment efficacy and safety. This study investigated the relationship between spot visibility threshold laser power and RPE melanin content, as measured by polarization-sensitive optical coherence tomography (PS-OCT), and examined differences in RPE melanin levels between the titration and treatment areas in subthreshold microsecond pulsing retinal laser therapy (SMPL).

Methods: Twelve eyes from 11 patients who underwent SMPL for macular edema and serous retinal detachment were included. In SMPL therapy, the threshold laser power was determined through titration outside the macula, near the vascular arcade. RPE melanin levels were evaluated based on polarimetric entropy (PE) measured by PS-OCT. The relationships between the visibility threshold laser power observed in funduscopy, RPE-PE in the titration area, and RPE-PE in three distinct macular regions were analyzed.

Results: A significant inverse correlation was observed between visibility threshold laser power (1125.0 ± 154.5 mW) and RPE-PE in the titration area (0.50 ± 0.09; p = 0.028; adjusted R² = 0.34; linear regression). RPE-PE values in the central macular region (0.57 ± 0.07) were correlated with those in the titration area (p = 0.025; adjusted R² = 0.35) but were significantly higher (p < 0.01; Wilcoxon signed-rank test). The ratio of macular to titration RPE-PE values was 1.15 ± 0.17, with considerable interindividual variability.

Conclusion: The inverse correlation between individual visibility threshold laser power and RPE-PE, along with discrepancies in melanin density between the titration and macular regions, suggests that variations in RPE melanin density substantially influence the efficacy and safety of SMPL. These findings support the potential utility of PS-OCT-based RPE melanin assessment for optimizing SMPL parameters.

Background: Energy-based treatments for atrophic acne scars (AAS) in darker skin phototypes must balance efficacy with pigmentary safety. While the nonablative 675-nm laser has shown promise with minimal risk of adverse effects, prospective data in Asian populations remain limited. This study evaluated the efficacy, tolerability, and safety of a 675-nm laser for AAS in Fitzpatrick skin types (FSTs) III-IV.

Methods: Sixteen adults with AAS underwent 3 monthly sessions using sequential Moveo (low-fluence scanning) and Standard (fractional stamping) modes. Outcomes were assessed at baseline and at 1, 3, and 6 months after the final session, including Goodman and Baron quantitative scores (GBQGASGS), Antera® 3D imaging device, patient satisfaction, procedural pain, and adverse events.

Results: GBQGASGS improved by 14.5% at 6 months after the final treatment (19.81 ± 7.31 to 16.94 ± 7.18; p = 0.001), with a 9.7% reduction evident 1 month after the second session (p = 0.017). Antera® 3D analysis demonstrated improvements in skin texture (12.91 ± 4.25 to 11.38 ± 3.97; p = 0.002) and scar volume (2.54 ± 1.33 to 2.04 ± 1.26; p = 0.001). At 6 months, blinded evaluators reported ≥ 25% improvement in 50% of subjects, while 69% of patients reported ≥ 25% improvement. Adverse events were of low incidence and transient in nature, and no serious complications occurred.

Conclusions: The 675-nm laser demonstrated significant and sustained improvements in acne scar metrics in Asian patients with FST III-IV, supporting its role as a pigment-safe, nonablative option for atrophic acne scars in skin of color.

Trial registration: Thai Clinical Trials Registry: TCTR20250218009.

Background: Vulvar lichen sclerosus (VLS) is a chronic inflammatory condition predominantly affecting postmenopausal women, often leading to significant discomfort and impaired quality of life. Current treatments, such as topical corticosteroids, have limitations in efficacy and long-term safety. Fractional CO₂ laser therapy has emerged as a promising modality for managing VLS, but its combination with topical estrogen remains underexplored.

Objective: This study aimed to evaluate the efficacy and safety of combined fractional CO₂ laser and topical estrogen therapy in managing VLS in postmenopausal women.

Methods: A randomized controlled trial was conducted involving 60 postmenopausal women diagnosed with VLS. Participants were divided into two groups: the intervention group received fractional CO₂ laser therapy combined with topical estrogen ointment, while the control group received topical estrogen alone. Efficacy was defined as a significant reduction in vulvar lichen sclerosus symptom score (VLSSS), assessed at baseline, 3 months, and 6 months. Secondary outcomes included histopathological changes and patient-reported quality of life measures.

Results: At both 3 months and 1 year after treatment, the intervention group showed a significant reduction in VLSSS compared to the control group (p < 0.001). Histopathological analysis demonstrated reduced inflammation and fibrosis. Patient-reported outcomes revealed significant improvements in sexual function (FSFI) and quality of life (CECA10) in the combined therapy group. Additionally, the recurrence rate at 1 year was significantly lower in the intervention group (17.14%) than in the control group (31.43%, p < 0.001). No severe adverse events were reported.

Limitations: The study's sample size was relatively small, and the follow-up period was limited to 6 months, which may not capture long-term outcomes. Additionally, the single-center design may limit generalizability.

Conclusion: Combined fractional CO₂ laser and topical estrogen therapy is a safe and effective approach for managing VLS in postmenopausal women, offering significant symptom relief and improved quality of life. Further studies with larger cohorts and longer follow-up are warranted to confirm these findings.