The Potential Depigmenting Activity of Retinaldehyde

Background: Retinoids have been reported to exert depigmenting activity. Unlike most depigmenting agents that target tyrosinase, they are not phenolic agents and may act via different mechanisms. Objectives: We analysed the properties of retinaldehyde (RAL), a precursor of retinoic acid (RA), as a skin-lightening agent in various models. Methods: The viability and the depigmenting properties of RAL were assessed in murine melanocytes, in human reconstructed epidermis, and in mice and guinea pigs. The melanin content and cytotoxicity were assessed in melanocytes; in 3-dimensional models, the melanin concentration and the number of active melanocytes were determined. Results: RAL was taken up by melanocytes and mostly metabolised to retinol and retinyl esters, and to a lesser extent to RA. RAL decreased the melanin concentration of guinea pig ears and mouse tails by 54 and 74%, respectively, and decreased the number of active melanocytes by 42 and 77%, respectively. In reconstructed epidermis the melanin concentration was increased by 52%, whereas the number of active melanocytes decreased by 44%. Conclusion: RAL exerts a significant depigmenting activity with a mode of action that looks different from that of RA. Our data suggest a skin-lightening effect related to a melanolytic action (i.e. a decrease in melanin concentration, whatever the mechanism) rather than to melanocytotoxicity, besides other still unknown actions of RAL on melanocytes

The Combination of a Retinoid, a Phenolic Agent and an Antioxidant Improves Tolerance while Retaining an Optimal Depigmenting Action in Reconstructed Epidermis

BACKGROUND: Cutaneous pigmented lesions urge the need to find safe and effective treatments to lighten the skin. OBJECTIVE: The aim of this study was to combine a retinoid (retinaldehyde), a new phenolic agent (4-(1-phenylethyl)-resorcinol) and a proreducing agent (delta-tocopheryl-beta-D-glucopyranoside) to achieve synergistic actions for skin lightening. METHODS: The tolerance profile and the depigmenting properties of these agents were assessed in murine keratinocyte and melanocyte cell lines, as well as in a 3-dimensional model of reconstructed epidermis. RESULTS: Retinaldehyde and 4-(1-phenylethyl)-resorcinol induced a significant decrease of tissue viability in reconstructed epidermis, but this cytotoxicity was prevented by the addition of delta-tocopheryl-beta-D-glucopyranoside. The combination of the three agents was, however, efficient in decreasing the specific melanin content and the density of active melanocytes. CONCLUSION: A combination of various chemicals acting via different mechanisms allows a decrease in the toxicity of each compound alone while retaining optimal skin-lightening properties

Safety of topical methimazole for the treatment of melasma. Transdermal absorption, the effect on thyroid function and cutaneous adverse effects

Methimazole is an oral antithyroid compound that exhibits a skin-depigmenting effect when used topically. However, the effect of topical methimazole on thyroid function has not been reported. This study was aimed at assessing the safety of topical methimazole used to treat pigmented lesions, without affecting thyroid hormones due to systemic delivery. The pharmacokinetics of methimazole, either applied in the form of a 5% topical formulation to facial skin or taken orally in the form of a 5-mg tablet by 6 volunteers, were determined. In addition, the effect of long-term topical applications of 5% methimazole on the function of the thyroid gland in 20 patients with epidermal melasma was determined following 6 weeks of once-daily application. Cutaneous adverse effects of topical methimazole were determined. From 15 min up to 24 h after application, methimazole was undetectable in the serum of the individuals receiving single topical methimazole dosing. Methimazole, however, was detected in serum after 15 min of oral administration and remained detectable in serum up to 24 h after administration. Long-term topical methimazole applications in melasma patients did not induce any significant changes in serum TSH, free thyroxine and free triiodothyronine levels. Topical methimazole was well tolerated by the patients and did not induce any significant cutaneous side effects. Present data together with the previously shown non-cytotoxic and non-mutagenic characteristics of methimazole indicate that this agent could be considered as a safe skin-depigmenting compound for topical treatment of skin hyperpigmentary disorders in humans

Dressing/Wound Care for Laser Treatment

Laser procedures have become quite commonplace in the field of dermatology. Advancing technology, coupled with better management and prevention of side effects, has resulted in a large increase in laser procedures. As mentioned throughout this text, lasers are an appealing therapy for scars, photo-damage, ritides, and pigmentary disorders. Ablative lasers have been used effectively for years however with concerns of side effects and/or complications. Patient are also often dissuaded by the down-time required after ablative laser procedures. Furthermore, the demand for ablative procedures has decreased with non-ablative techniques dramatically on the rise. The non-ablative however, tend to have diminished efficacy compared to ablative techniques for many indications. With the rapid advances in laser technology there is a need to investigate optimal postoperative regimens so that we may deliver better outcomes and increase patient satisfactions

Dressings/Wound Care for Laser Treatment

Ablative and non-ablative lasers have different effects on the skin. Various postoperative treatments have been used, e.g., topical agents and/or dressings (open vs closed techniques).Additional research is needed to determine the optimal postoperative care after laser procedures