First, this study zooms in on what we know, and don't, and need to find out, about how the meibomian glands change as we age. We know that there is an age-related increase in MGD (the leading cause of dry eye disease), but we don't know why, and this study looks at a number of possible mechanisms that might be gradually eroding their healthy function. Of course, anything we can learn about the mechanism of natural change in the glands could conceivably be helpful for understanding MGD disease processes - and treatments - even where aging is not a factor. Anyway, the potential mechanisms of MGD suggested in the study are androgens, stem cells, growth hormone/IGF-1, insulin sensitivity, and converging signal FOXOs (don't ask me to explain what that means!)
Second, it identifies retinoic acid as a cause of MGD and dry eye disease and warns of the proliferation of anti-aging products that contain it:
Anti-aging skin care products, of which retinoids-based products are a major component, showed an annual growth rate of 11.8% from 2002 to 2007 and 9.7% from 2007 to 2012, far exceeding all the other skin care products combined…. Unfortunately one side effect of RA cream is dryness of the skin. In fact, retinoic acid (RA), also known as isotretinoin or Accutane, was initially used to treat acne before it found its way into the anti-aging cosmetics. It is highly effective in reducing sebaceous gland size by inhibiting sebocyte proliferation, differentiation and sebum production…. Not surprisingly, RA causes MGD and dry eye disease, given that meibomian gland is a sebaceous gland. 408 RA causes keratinization and thickening of the meibomian gland ducts…, degeneration and necrosis of the acinar cells, fibrosis of the periacinar tissue, and reduced lipid content in meibomian gland…. Further, isotretinoin exposure is associated with tear film instability and hyperosmolarity, dry eye symptoms and blepharitis…. In effect, RA promotes MGD and evaporative dry eye disease.Anyway, here's the abstract:
Aging and dry eye disease.
Dry eye disease is a prevalent eye disorder that in particular affects the elderly population. One of the major causes of dry eye, meibomian gland dysfunction (MGD), shows increased prevalence with aging. MGD is caused by hyperkeratinization of the ductal epithelium of meibomian gland and reduced quantity and/or quality of meibum, the holocrine product that stabilizes and prevents the evaporation of the tear film. Of note, retinoids which are used in current anti-aging cosmetics may promote the development of MGD and dry eye disease. In this review, we will discuss the possible mechanisms of age-related MGD.
Exp Gerontol. 2012 Apr 28. [Epub ahead of print]
Ding J,
Sullivan DA.
2 comments:
"RA causes MGD and dry eye disease" - I believe this is referring to SYSTEMIC RA, not topically applied product, which would have a much lower absorption rate.
Actually RA is absorbed through the skin quite readily, since it is a small, hydrophilic molecule. It is a vitamin A derivative, and it can be stored in the fat in large amounts. So the RA in the eye cream that you apply on your lids will have no problem diffusing into the skin, through the connective tissue, then right onto your meibomian glands. Topical application has another issue in that you can easily over dose topically by applying the anti-aging serum or cream repeatedly.
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