The comparison of skin rejuvenation effects of vitamin A, fractional laser, and their combination on rat

Low-power therapeutic lasers on mRNA levels

Gene expression evaluation in cells and biological tissues has been crucial for research in biology, medicine, biotechnology, and diagnostic. Messenger ribonucleic acid (mRNA) levels show relationship with gene expression, and they can be measured by real-time quantitative polymerase chain reaction (RT-qPCR) for the quantification of steady-state mRNA levels in cells and biological tissues. Radiations emitted from low-power lasers induce photobiomodulation, which is the base of therapeutic protocols for disease treatment. Despite that the understanding on photobiomodulation has been improved by mRNA level evaluation, laser irradiation parameters and procedures are diversified among studies, harming the comparison of RT-qPCR data. In this systematic review, data from mRNA levels reported in photobiomodulation studies were summarized regarding the process, function, and gene. Literature search was conducted for the assessment of published reports on mRNA levels evaluated by RT-qPCR in cells and biological tissues exposed to low-power lasers. Data showed that mRNA levels have been evaluated by RT-qPCR for a variety of genes related to molecular, cellular, and systemic processes after low-power violet-orange, red, and infrared laser exposure. Results from gene expression have increased the understanding of the mechanisms involved in photobiomodulation, and they can be useful to increase the efficacy and safety of clinical applications based on low-power lasers.

Transcriptomic analysis of human skin wound healing and rejuvenation following ablative fractional laser treatment

Ablative fractional laser treatment is considered the gold standard for skin rejuvenation. In order to understand how fractional laser works to rejuvenate skin, we performed microarray profiling on skin biopsies to identify temporal and dose-response changes in gene expression following fractional laser treatment. The backs of 14 women were treated with ablative fractional laser (Fraxel®) and 4 mm punch biopsies were collected from an untreated site and at the treated sites 1, 3, 7, 14, 21 and 28 days after the single treatment. In addition, in order to understand the effect that multiple fractional laser treatments have on skin rejuvenation, several sites were treated sequentially with either 1, 2, 3, or 4 treatments (with 28 days between treatments) followed by the collection of 4 mm punch biopsies. RNA was extracted from the biopsies, analyzed using Affymetrix U219 chips and gene expression was compared between untreated and treated sites. We observed dramatic changes in gene expression as early as 1 day after fractional laser treatment with changes remaining elevated even after 1 month. Analysis of individual genes demonstrated significant and time related changes in inflammatory, epidermal, and dermal genes, with dermal genes linked to extracellular matrix formation changing at later time points following fractional laser treatment. When comparing the age-related changes in skin gene expression to those induced by fractional laser, it was observed that fractional laser treatment reverses many of the changes in the aging gene expression. Finally, multiple fractional laser treatments, which cover different regions of a treatment area, resulted in a sustained or increased dermal remodeling response, with many genes either differentially regulated or continuously upregulated, supporting previous observations that maximal skin rejuvenation requires multiple fractional laser treatments. In conclusion, fractional laser treatment of human skin activates a number of biological processes involved in wound healing and tissue regeneration.

Involvement of microRNAs as a Response to Phototherapy and Photodynamic Therapy: A Literature Review

The current knowledge about the mechanisms of action of light-based treatments (chiefly photodynamic therapy and phototherapy) in skin diseases leans to the possible involvement of epigenetic and oxidative stress mechanisms. To better understand and exploit, to the fullest, these relatively safe and reproducible treatments, several studies have focused on miRNAs, small non-encoding RNAs (22–24 nucleotides), after light-based treatments. The current narrative review focused on 25 articles. A meta-analysis was not deemed appropriate. The results gather the most recurrent skin-related miRNAs up- or downregulated after light treatment. Five of these, miR-21, -29, -125, -145 and -155, are either the most consistently related to efficacy/resistance to treatment or identified as helpful diagnostic tools. A specific class of miRNAs (angioMIRs) requires further studies. Future treatments and imaging techniques could benefit greatly from the use of antagomirs as a possible co-adjuvant therapy along with light-based treatments.