A comparative evaluation of tretinoin gel microsphere, 0.1%, versus tretinoin cream, 0.025%, in reducing facial shine

Tretinoin gel microsphere, 0.1%, is a highly effective anti-acne medication formulated with sponge-like microspheres encapsulating the active ingredient, tretinoin. In addition to minimizing cutaneous irritation, this system may also reduce facial shine. This single-center, double-blind, half-face study evaluated the potential of tretinoin gel microsphere, 0.1%, to reduce the appearance of facial shine compared to tretinoin cream, 0.025%. Thirty-five subjects (ages 12 to 24 years) with moderate acne vulgaris and moderate facial oiliness, were evaluated after 4 consecutive days of product use. On sides treated with tretinoin gel microsphere, 0.1%, investigators found significantly reduced facial shine at 3 and 6 hours posttreatment. Subjects' self-evaluations revealed a significant reduction in facial shine at 3 hours posttreatment. Photographic analyses showed reductions in facial shine for both treatments, but decreases were greater on tretinoin gel microsphere, 0.1%-treated sides. Both therapies were well tolerated, and no adverse events occurred. Tretinoin gel microsphere, 0.1%, has the added benefit of reducing the appearance of facial shine, which is a frequent concern in acne patients.

Targeting expression of a dominant-negative retinoic acid receptor mutant in the epidermis of transgenic mice results in loss of barrier function

To study the effects of retinoic acid on the skin in vivo, we have subverted the activity of endogenous receptors by targeting expression of a dominant negative mutant of retinoic acid receptor alpha (RAR alpha) to the epidermis of transgenic mice. At birth, mice expressing the mutant RAR alpha transgene exhibited a marked phenotype of a red, shiny skin that was somewhat sticky to touch. Severely affected neonates died within 24 hr. Histological changes in the epidermis were subtle with the phenotypic stratum corneum appearing slightly thinner and more loosely packed than in controls. Electron microscopic studies revealed that lipid multilamellar structures were not present between cells in the stratum corneum of phenotypic mice. When assayed for transepidermal water loss, phenotypic skin lost water at a rate three times faster than controls, suggesting that neonatal lethality resulted from loss of epidermal barrier function. The absence of a functional lipid barrier in transgenic mice first became evident at E17 when lipids were extruded initially into the intercellular space. We have identified a potential pathway linking inhibition of retinoid signaling with disruption of the lipid barrier that involves peroxisome proliferator-activated receptors. This study documents the role of the retinoid signaling pathway in formation and maintenance of a functional epidermis and provides the first evidence that this is mediated in part by modulation of lipid metabolism.