Another reason to look at the dermal/epidermal junction: sun spots, vitiligo and melasma

The dermal-epidermal junction is so thin (in a microscope it is just a line that we may be tempted to ignore it completely. And yet, it is crucial to skin’s health. It is also critical to some problems that many of us consider very annoying: sun spots that appear as we age.  Others don’t have to wait that long: they are afflicted with melasma or vitiligo much earlier in life.

These are all disorders of pigmentation, and, apparently, disruption of the dermal/epidermal junction may be the starting event in disorders of pigmentation initiated by factors like UV radiation.   Once the chain of events is initiated, keratinocytes don’t adhere properly and growth factors are not produced.  Why is defective adherence so important? Because almost anything can lead to the exfoliation (loss) of keratinocytes and pigmented cells, leading to thinner skin and irregular pigmentation.

In the miscroscope, the basement membrane in the melasma lesions appears disrupted and disorganized, and the melanocytes are deformed. Chronic exposure to UV radiation leads to increased metalloproteinase activity, which may be responsible for the dysfunction of the basement membrane. Dermal-epidermal interactions increase, and the disrupted signalling among melanocytes and other skin cells may cause the melasma lesions.

Environmental factors may lead to defective keratinocyte adhesion and decreased release of keratinocyte-derived growth factors. Later on, a secondary event like physical trauma, oxidative stress or autoantibodies, may lead to exfoliation of keratinocytes and pigmented cells and the white spots characteristic of vitiligo.

Actives that can help the dermal epidermal junction: apocynin, ROS BioNet, keratinocyte growth factor.