THE SKIN ENDOCANNABINOID SYSTEM
The centrality of skin function to human health has meant that evolution endowed skin with complex biochemical networks of receptors and small molecules that continually survey and respond to inputs, and modify the reactions of resident cells to react to incoming information.
One such network is the skin endocannabinoid system (SkECS), where endogenous and exogenous cannabinoids can act at numerous receptor sites to promote skin health. Cannabinoid receptors (CB1, CB2, TRPV1, TRPA1 and TRPV4) are present on multiple cell types in the human skin (fibroblasts, keratinocytes, immune cells, neurons, subcutaneous fat cells and muscle layers).
The presence of the SkECS is a clear indicator that cannabinoids may be central to skin health. It also presents the intriguing possibility that exogenously applied cannabinoids could augment, initiate or supplement the roles that endocannabinoids play in the skin to therapeutic benefit.
Cannabinoids and their diverse receptors have been implicated in the proliferation of skins cells, in the differentiation processes that give rise to the multicellular complexity of skin, in hormone and mediator secretion that maintain skin tone, and in the activity of hair follicle cells and the sebaceous glands.
The SkECS maintains skin homeostasis, and loss of this homeostasis leads to disorders such as acne, dermatitis, itch, pain, psoriasis, sclerosis and excessive or unwanted hair growth.
CBD TARGETS FOR SKIN HEALTH
Epidermis – psoriasis – Phyto-cannabinoids inhibit keratinocyte proliferation, decrease keratinization and suppress cornified envelop formation; promote epidermal differentiation; inhibit proliferation of transformed (tumorigenic) keratinocytes.
Sebaceous glands – CB2 ligands stimulate lipid and sebum production and apoptosis of glandular cells.
Hair follicles – Anandamide inhibits hair shaft elongation and proliferation, promote intraepithelial apoptosis and catagen regression.
Dermatitis – Cannabinoid receptors suppress inflammation.
Dermal fibrosis – Cannabinoid receptors suppress fibrosis.
UV-B induced skin tumors and skin inflammation – Cannabinoid receptors suppress UV-B induced skin tumors and skin inflammation, resulting in decreased growth, angiogenesis, metastasis and apoptosis.
Sources and acknowledgments
“Evolved To Defend: Cannabinoid Protection Of Barrier Tissues In Plants And Humans”. Andrea L. Small-Howard, Ph.D.