Photobiomodulation for melasma treatment: Integrative review and state of the art.

PURPOSE: Photobiomodulation therapy (PBM) is a versatile technique for treating skin diseases. Melasma, a chronic hyperpigmentation condition, has recently been associated with vascular features and dermal photoaging and poses significant management challenges. We review the recent literature on melasma etiology and the evidence supporting PBM as a therapeutic modality for melasma treatment. METHODS: We conducted a comprehensive literature search in three different databases from May to August 2023, focusing on studies published in the past 10 years. The inclusion criteria comprised full-text studies investigating low-power lasers and/or light-emitting diodes (LEDs) in in vitro or in vivo models, as well as clinical trials. We excluded studies discussing alternative melasma therapies or lacking experimental data. We identified additional studies by searching the reference lists of the selected articles. RESULTS: We identified nine relevant studies. Clinical studies, in agreement with in vitro experiments and animal models, suggest that PBM effectively reduces melasma-associated hyperpigmentation. Specific wavelengths (red: 630 nm; amber: 585 and 590 nm; infrared: 830 and 850 nm) at radiant exposures between 1 and 20 J/cm2 exert modulatory effects on tyrosinase activity, gene expression, and protein synthesis of melanocytic pathway components, and thus significantly reduce the melanin content. Additionally, PBM is effective in improving the dermal structure and reducing erythema and neovascularization, features recently identified as pathological components of melasma. CONCLUSION: PBM emerges as a promising, contemporary, and non-invasive procedure for treating melasma. Beyond its role in inhibiting melanogenesis, PBM shows potential in reducing erythema and vascularization and improving dermal conditions. However, robust and well-designed clinical trials are needed to determine optimal light parameters and to evaluate the effects of PBM on melasma thoroughly.

Low-intensity pulsed ultrasound (LIPUS) stimulates mineralization of MC3T3-E1 cells through calcium and phosphate uptake.

The present study aimed to evaluate the effect of low-intensity pulsed ultrasound (LIPUS) on pre-osteoblast mineralization using in vitro bioassays. Pre-osteoblastic MC3T3-E1 cells were exposed to LIPUS at 1 MHz frequency, 0.2 W/cm2 intensity and 20% duty cycle for 30 min. The analyses were carried out up to 336 h (14 days) after exposure. The concentration of collagen, phosphate, alkaline phosphatase, calcium and transforming growth factor beta 1 (TGF-ß1) in cell supernatant and the presence of calcium deposits in the cells were analyzed. Our results showed that LIPUS promotes mineralized nodules formation. Collagen, phosphate, and calcium levels were decreased in cell supernatant at 192 h after LIPUS exposure. However, alkaline phosphatase and TGF-ß1 concentrations remained unchanged. Therapeutic pulsed ultrasound is capable of stimulating differentiation and mineralization of pre-osteoblastic MC3T3-E1 cells by calcium and phosphate uptake with consequent hydroxyapatite formation.

Immediate effect and safety of HIFU single treatment for male subcutaneous fat reduction.

BACKGROUND: The increasing search for procedures for fat reduction is related to dissatisfaction with body shape. High-intensity focused ultrasound (HIFU) has been proven effective in body sculpting when used noninvasively to reduce subcutaneous fat and improve body contour. AIMS: This study aimed to evaluate the immediate effect and safety of HIFU single treatment for male localized fat and body remodeling. PATIENTS/METHODS: Twenty-four male subjects (18 to 59 years old) with BMI ≤ 30 kg/cm² and at least 2 cm of abdominal fat received a single HIFU treatment session. Individuals were subjected to abdominal measurements before and after procedure. In addition, biochemical analyses of blood samples were performed to assess possible inflammatory effects or oxidative stress induction by the treatment. RESULTS: High-intensity focused ultrasound was found to be an effective treatment in reducing localized adiposities in the abdominal region. A significant decrease (0.6%) was observed in infraumbilical circumference of subjects submitted to HIFU single treatment when compared with control subjects. The laboratory parameters did not present any appreciable changes. CONCLUSION: This study further strengthens the current view that HIFU is an effective and safe tool for localized fat reduction.