A prospective study of adverse reactions of ALA-PDT for acne vulgaris

Unveiling the mechanism of photothermal therapy in acne man-agement: targeting sebaceous gland ferroptosis via umbilical cord mesenchymal stem cell membrane-encapsulated Au-Ag-PDA

Background

Branched gold and silver nanoparticles coated with polydopamine (Au-Ag-PDA) demonstrate high photothermal conversion efficiency. Utilizing umbilical cord mesenchymal stem cell membranes (MSCM) as an effective drug delivery system, our preliminary studies investigated the suppression of sebum secretion in sebaceous glands using MSCM-coated Au-Ag-PDA nano-particles (Au-Ag-PDA@MSCM) combined with 808 nm laser irradiation, showing potential for dermatological applications in acne treatment.

Methods

This study employs proteomic analysis, complemented by subsequent techniques such as Western blotting (WB), small interfering RNA (siRNA), and transmission electron microscopy, to further investigate the differential mechanisms by which Au-Ag-PDA and Au-Ag-PDA@MSCM-mediated photothermal therapy (PTT) suppress sebum secretion.

Results

Our proteomic analysis indicated mitochondrial respiratory chain damage in sebaceous gland tissues post-PTT, with further validation revealing ferroptosis in sebaceous cells and tissues. Acyl-CoA Synthetase Long-Chain Family Member 4 (Acsl4) has been identified as a critical target, with Au-Ag-PDA@MSCM demonstrating enhanced ferroptotic effects.

Conclusion

These findings significantly advance our understanding of how PTT mediated by Au-Ag-PDA@MSCM nanoparticles reduces sebum secretion and underscore the pivotal role of MSCM in inducing ferroptosis in sebaceous glands, thus providing a robust theoretical foundation for employing PTT via specific molecular pathways in acne treatment.

Long-Term Improvement of Different Types of Acne Vulgaris Using a Mild Photodynamic Therapy Protocol with BF-200 ALA Gel: A Series of Cases

Background: Photodynamic therapy (PDT) can be a promising alternative for patients with acne vulgaris. Our study aimed to evaluate the efficacy and safety of red light photodynamic therapy with BF-200 ALA gel in the treatment of different types of acne vulgaris. Methods: We performed a retrospective, observational study of a series of 22 cases. All patients were treated according to a mild PDT protocol. After a careful wash of the affected skin areas, BF-200 ALA gel was applied to the skin in a thin layer and incubated for 30 min, followed by illumination using narrow-spectrum red light (635 nm) at a dose of 4 J/cm2. Most patients received one (36.4%), two (27.3%), or three (22.7%) PDT sessions. About a third of the patients received concomitant acne treatment with topical retinoids. Results: Patients of 25.1 ± 8.9 years suffering from papulopustular (45.5%), nodular (27.3%), and comedonal acne (27.3%) in the face were included. Irrespective of acne type or severity, 95.5% of patients had good or excellent responses to the treatment with PDT (≥60% lesion clearance). We found no association between concomitant acne medication and the favorable results achieved by PDT. Most patients reported no adverse events (72.7%), except for six patients who experienced erythema. The good efficacy results were maintained over a follow-up period of 12.5 ± 10.8 months. Conclusions: In this study, we show that PDT with BF-200 ALA gel and low light dose is an effective and long-lasting option for the treatment of different acne types.

Increased PDT Efficacy When Associated with Nitroglycerin: A Study on Retinoblastoma Xenografted on Mice

Purposes: The aim of the study was to assess the efficacy of a treatment protocol that combines photodynamic therapy (PDT) and nitroglycerin (NG) on human retinoblastoma tumors xenografted on mice. We aimed to increase the PDT efficiency (in our least treatment-responsive retinoblastoma line) with better PS delivery to the tumor generated by NG, which is known to dilate vessels and enhance the permeability and retention of macromolecules in solid tumors. Methods: In vivo follow-up of the therapeutic effects was performed by sodium MRI, which directly monitors variations in sodium concentrations non-invasively and can be used to track the tumor response to therapy. NG ointment was applied one hour before PDT. The PDT protocol involves double-tumor targeting, i.e., cellular and vascular. The first PS dose was injected followed by a second one, separated by a 3 h interval. The timelapse allowed the PS molecules to penetrate tumor cells. Ten minutes after the second dose, the PS was red-light-activated. Results: In this study, we observed that the PDT effect was enhanced by applying nitroglycerin ointment to the tumor-bearing animal’s skin. PDT initiates the bystander effect on retinoblastomas, and NG increases this effect by increasing the intratumoral concentration of PS, which induces a higher production of ROS in the illuminated region and thus increases the propagation of the cell death signal deeper into the tumor (bystander effect).