The Optimal Application of Medium Potency Topical Corticosteroids in Preventing Laser-Induced Inflammatory Responses-An Animal Study

Delayed Collagen Production without Myofibroblast Formation Contributes to Reduced Scarring in Adult Skin Microwounds

In adult mammals, wound healing predominantly follows a fibrotic pathway, culminating in scar formation. However, cutaneous microwounds generated through fractional photothermolysis, a modality that produces a constellation of microthermal zones, exhibit a markedly different healing trajectory. Our study delineates the cellular attributes of these microthermal zones, underscoring a temporally limited, subclinical inflammatory milieu concomitant with rapid re-epithelialization within 24 hours. This wound closure is facilitated by the activation of genes associated with keratinocyte migration and differentiation. In contrast to macrothermal wounds, which predominantly heal through a robust myofibroblast-mediated collagen deposition, microthermal zones are characterized by absence of wound contraction and feature delayed collagen remodeling, initiating 5-6 weeks after injury. This distinct wound healing is characterized by a rapid re-epithelialization process and a muted inflammatory response, which collectively serve to mitigate excessive myofibroblast activation. Furthermore, we identify an initial reparative phase characterized by a heterogeneous extracellular matrix protein composition, which precedes the delayed collagen remodeling. These findings extend our understanding of cutaneous wound healing and may have significant implications for the optimization of therapeutic strategies aimed at mitigating scar formation.

Clinical Evaluation and Experience in Treatments Performed with Fractional CO2 Laser on Latin American Skin: An Observational Retrospective Study

Background: The carbon dioxide (CO₂) laser is an ablative system that evaporates, remodels, and coagulates tissues, becoming therefore a gold standard piece of equipment for the treatment of dermatological pathologies and esthetic imperfections. Objective: To evaluate the efficacy and safety of CO₂ laser treatments in different patients' skin pathologies. Methods: A total of 705 patients with an age range between 18 and 70 years, with phototypes on the Fitzpatrick scale III, IV, V, and VI, were enrolled from October 2021 to May 2022, and were treated using the CO₂ laser system. Results: Ninety-six patients were treated with fractional CO₂ laser, used for skin rejuvenation and stretch marks. One patient presented reactivation of herpes simplex, 10 postinflammatory hyperpigmentation that resolved after 3 months with depigmenting agents, 6 with persistent erythema. A total of 13 patients with rhinophyma were treated, and no complications were observed; a total of 64 patients with wrinkles were treated. They improved in 6 months. A total of 340 patients were treated for seborrheic keratosis, papulosa nigra dermatosis, fibropapillomas, sebaceous hyperplasias, verruca vulgaris, and condylomata acuminata. One patient presented with a complication hypopigmented macule. A total of 136 patients underwent treatment for laser ablation of intradermal nevi and verrucous epidermal nevi, without complications. A total of 56 patients were treated with keloids and hypertrophic scars. One patient presented with ulceration of a keloid that resolved with the application of clostridiopeptidase A and chloramphenicol after 2 weeks. Conclusions: The use of the CO₂ laser in any phototype and race, which are factors with a high incidence in Latin America, provides a safe and effective result for different dermatological pathologies.

Practice patterns regarding combination treatments and laser and energy based devices: A survey of American Society for Laser Medicine and Surgery Members

OBJECTIVE

The use of laser and energy-based devices (LEBD) has grown exponentially in recent years, and variations in common practices exist. Our study sought to evaluate the current practice paradigms of leaders in the field of LEBD with regard to antimicrobial prophylaxis, adjuvant topical treatments, use of laser procedures in pregnancy, and combination of procedures.

METHODS

Anonymous surveys were distributed to leading dermatologists in American Society for Laser Medicine & Surgery (ASLMS) via email.

RESULTS

Surveys were distributed to 65 ASLMS members; 37 submitted responses. Routine antiviral prophylaxis is used by 76% for fractional ablative procedures of the face, but only 27% for fractional non-ablative procedures. Routine antifungal prophylaxis was used by a minority (16%) for ablative procedures, whereas antibacterial prophylaxis was used by 68%, with varying antibiotics. Wide variations exist in skin preparation and topicals used post-laser treatment. Most respondents feel comfortable combining same-day LEBD and botulinum toxin injections, specifically vascular or Q-switched/picosecond lasers. Most respondents avoid performing LEBD during pregnancy.

CONCLUSIONS

Expert consensus in a rapidly growing field sheds light on common, reliable practices. However, even at the expert level, variations exist. Further high-quality research is needed to standardize and update guidelines.

Synergistic Sequential Emission of Fractional 10.600 and 1540 nm Lasers for Skin Resurfacing: An Ex Vivo Histological Evaluation

Background: Fractional ablative and non-ablative lasers are useful treatments for skin rejuvenation. A procedure that provides the sequential application of fractional ablative followed by non-ablative laser treatment may reduce patients' downtime and deliver better cosmetic results than with either laser alone. Objective: The purpose of the current study was to demonstrate the ameliorative and therapeutic effects in skin remodeling of the synergistic use of the two laser wavelengths (fractional ablative CO₂ and non-ablative 1540 nm) with three different types of pulse shapes, S-Pulse (SP), D-Pulse (DP) and H-Pulse (HP), through which the CO₂ laser can emit, performing an ex vivo histological evaluation. Methods: In this prospective study, ex vivo sheep inner thigh skin was chosen due to its similarity to human skin tissue, and a histological evaluation was performed. Three irradiation conditions, using all of the three CO₂ pulse shapes (alone or averaged), were investigated: (1) 10.600 nm alone, the sequential irradiation of the two wavelengths in the same perfectly controlled energy pulses (DOT) for the entire scan area; ((2) 10.600 nm followed immediately by 1540 nm; and (3) 1540 nm followed immediately by 10.600 nm). Results: When comparing ablative to sequential irradiations, the synergy of the two wavelengths did not alter the typical ablative pulse shape of the 10.600 nm laser alone. With the same CO₂ pulse shape, the lesion depth did not vary with the synergy of the two wavelengths, while thermal lesion width increased compared to CO₂ alone. The ablation rate was achieved, while the total thermal lesion coverage in the scanning area of CO₂ - 1540 lasers was greater than when using CO₂ alone and then the other sequential irradiation. Conclusions: This study provides important preclinical data for new and early uses of the novel 10.600/1540 nm dual-wavelength non-ablative fractional laser. The synergy of the two wavelengths enhanced all the benefits already available when using CO₂ laser systems both in terms of tone strengthening, thanks to a greater shrinking effect, and in terms of stimulation and collagen remodeling thanks to a greater volumetric thermal effect.