Improvement of naturally aged skin with vitamin A (retinol).
Ageing skin is characterised by the appearance of, for example, fine lines and wrinkles, sagging, looseness and discoloration. Many of the changes occur in the dermal layers as a result of a cumulative exposure to UVA over a lifetime. UVA penetrates deep into the skin reaching the dermis, while UVB is thought to be mostly responsible for any signs of erythema, skin burning and tanning. Sun exposure results in the generation of free radicals leading to a reduction in collagen and elastin fibres and an increase in proteases responsible for degrading these proteins. Collagen and elastin provide the supporting network for the dermis, therefore damage to these fibres leads to the reported reduction in the firmness of the skin and a wrinkled appearance. These signs of photoageing can be alleviated to some extent with retinoic acid treatment. Additionally, skin ages due to intrinsic changes, under the control of genes and hormones. This is the subject of this investigation, although many studies have looked at treating photodamage there are few available studies on intrinsically aged or 'naturally' aged skin.
In order to study skin that had aged purely from intrinsic changes, a non-sun-exposed site of the body was chosen--the upper inner portion of the arm. Treatment, containing 0.4% all-trans-retinol, was applied to one arm and vehicle lotion was applied to the other arm. Assignment of product was random, and approximately 2ml of lotion was applied to the arms.
Recruited subjects were at least 80 years of age (average age 87 years) and both male and female subjects were enrolled. A total of 23 subjects completed the 24 week study. Clinical results showed that retinol treatment to the arm significantly reduced the fine wrinkling scores compared to vehicle treatment. The reduction in fine wrinkling was observed at 4 weeks and continued to week 24. Improvements in tactile roughness and overall severity of aged skin was also seen with the retinol treatment. Biopsy data showed that retinol increased glycosoaminoglycans (GAG) expression and produced a significant increase in immunostaining for collagen I from baseline to week 24, compared to the vehicle-treated arm.
The authors indicated that retinol treatment was well tolerated by the subjects, although by week 24 most participants reported some degree of cutaneous irritation on the retinol-treated arm. This included erythema, peeling, pruritus, dryness and burning/stinging. In all, three subjects withdrew from the study due to adverse reactions.
This study examines the effect of retinol treatment on intrinsic ageing. Previously, retinol and retinoic acid usage has been investigated in photodamaged skin. In fact, retinoic acid usually requires at least 2-3 months of treatment before improvements are visible on photodamaged skin. The improvements in this study occurred in a much shorter time frame (4 weeks), and the authors speculate that this points to differences in wrinkle architecture between intrinsically aged and sun-damaged skin.
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|Date:||Mar 1, 2008|
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