Split-Sided Chest Study of Skin Rejuvenation Comparing Low-Energy, 1,927-nm Thulium Fractional Laser Treatment Prior to Photodynamic Therapy Versus Photodynamic Therapy Alone

A Review of the Dermatologic Clinical Applications of Topical Photodynamic Therapy

Topical photodynamic therapy is a widely approved therapy for actinic keratoses and low-risk nonmelanoma skin cancers with a rapidly growing range of emerging indications for other cutaneous diseases. This review summarizes the best-available evidence to provide a clinical update for dermatologists on the approved and emerging indications of photodynamic therapy. The body of evidence suggests that photodynamic therapy is superior or noninferior to other available treatment modalities for actinic keratoses, low-risk basal cell carcinomas, Bowen's disease, skin field cancerization, chemoprevention of keratinocyte carcinomas in organ transplant recipients, photoaging, acne vulgaris, and cutaneous infections including verrucae, onychomycosis, and cutaneous leishmaniasis. There is emerging evidence that photodynamic therapy plays a role in the management of actinic cheilitis, early-stage mycosis fungoides, extramammary Paget disease, lichen sclerosis, and folliculitis decalvans but there are no comparative studies with other active treatment modalities. Common barriers to topical photodynamic therapy include procedural pain, costs, and the time required for treatment delivery. There is significant heterogeneity in the photodynamic therapy protocols reported in the literature, including different photosensitizers, light sources, number of treatments, time between treatments, and use of procedural analgesia. Topical photodynamic therapy should be considered in the management of a spectrum of inflammatory, neoplastic, and infectious dermatoses. However, more comparative research is required to determine its role in the treatment algorithm for these dermatologic conditions and more methodological research is required to optimize photodynamic therapy protocols to improve the tolerability of the procedure for patients.

Low-fluence treatment with a novel fractionated 2,910-nm fiber laser improves photodamage

BACKGROUND

Facial rejuvenation by lasers that target water has been a mainstay of esthetic laser treatments for decades. Modern lasers more commonly treat a fraction of the skin surface using ablative, semi-ablative, or nonablative pulses.

METHODS

Twenty subjects with visible evidence of chronic photoaging on the face were enrolled in this study. All subjects received two full-face, single-pass treatments spaced 2 months apart with the superficial mode of a 2910 nm fiber laser with an estimated penetration depth of 10 μm, 25% coverage, delivered in a 15 mm × 15 mm square microbeam pattern. A blinded comparison of pretreatment and 3-month post-treatment images was performed. Evaluation of biopsy samples for laser-tissue effects was performed on three separate subjects and biopsies were harvested 1-day post-treatment, 1-week post-treatment, and 2-weeks post-treatment.

RESULTS

Blinded evaluation of digital images revealed an average improvement score of 25.1 ± 14.5 (mean ± SEM) or 25.1%, using an 11-point scale evaluating overall improvement in photoaging (p < 0.001). Post-treatment effects were limited to mild-to-moderate erythema and edema, and the pain was rated a 1.9 out of a maximum of 10. Histology demonstrated superficial changes in the stratum corneum and epidermis with dermal inflammation present at 1-day post-treatment and 1-week post-treatment, with a return to baseline at 2 weeks.

CONCLUSIONS

The 2910 nm fiber laser is safe and effective for improving mild photodamage, with minimal discomfort and downtime. Dermal inflammation results from very superficial epidermal injury and may contribute to clinical improvement.

The photosensitizer-based therapies enhance the repairing of skin wounds

Wound repair remains a clinical challenge and bacterial infection is a common complication that may significantly delay healing. Therefore, proper and effective wound management is essential. The photosensitizer-based therapies mainly stimulate the photosensitizer to generate reactive oxygen species through appropriate excitation source irradiation, thereby killing pathogenic microorganisms. Moreover, they initiate local immune responses by inducing the recruitment of immune cells as well as the production of proinflammatory cytokines. In addition, these therapies can stimulate the proliferation, migration and differentiation of skin resident cells, and improve the deposition of extracellular matrix; subsequently, they promote the re-epithelialization, angiogenesis, and tissue remodeling. Studies in multiple animal models and human skin wounds have proved that the superior sterilization property and biological effects of photosensitizer-based therapies during different stages of wound repair. In this review, we summarize the recent advances in photosensitizer-based therapies for enhancing tissue regeneration, and suggest more effective therapeutics for patients with skin wounds.