The cutaneous Endocannabinoid System (SEC) has been demonstrated in the skin not only at the level of neuronal endocannabinoids: the endocannabinoids anandamide and 2-arachidonoylglycerol (2-AG), the CB1, CB2 and TRPV1 receptors and the enzymes involved in the biosynthesis and degradation of endocannabinoids (FAAH, MAGL, etc …).
The components of the SEC have been found, to varying degrees, on almost all the cells that make up the skin: epidermal keratinocytes, melanocytes, mast cells, fibroblasts, sebocytes, sweat glands and even on some types of hair follicles. In the skin, the role of the SEC is that of regulator of various functions: cell growth, proliferation and apoptosis, inflammatory and immune responses, transmission of sensory stimuli to the central nervous system and synthesis of lipids and other components of the epidermis.
As for Psoriasis, the treatments currently available range from the use of topical preparations – containing emollients, vitamin D analogues, cortisone, etc … – and phototherapy for mild-moderate forms, up to the use of systemic therapies with cyclosporine. , methotrexate, and biologics, for the more severe forms.
Despite the effectiveness of these treatments, the significant side effects they entail, push for the search for new therapies.
Cannabinoids have shown promise in the treatment of psoriasis. Several mechanisms are proposed: antiproliferative effects on keratinocytes, inhibition of the action of immune cells (macrophages and lymphocytes), the release of inflammatory cytokines and angiogenesis. (2)
The CB2 receptors, due to their localization on immune cells, would seem to be those most involved in these actions. CB1 and PPARγ receptors also play an important role in psoriasis. Various pre-clinical studies have demonstrated the validity of phytocannabinoids or analogues which, by acting on these receptors, improve the symptoms of psoriasis.
Even in dermatitis, various researches show that modulating the action of the SEC could give good results. In a study conducted on laboratory animals, it was found that CB2 receptors are involved in contact dermatitis, so called because they are caused by contact with irritants or allergens: using both agonists and antagonists of CB2, there was an increase in inflammation , but, by using inverse agonists (which bind and inactivate the receptor), both systemically and topically, a decrease in inflammation was obtained.
Finally, in dermatological pruritus, the application of cannabinoids is very promising because both CB1 and CB2 receptors and TRPV1 are involved in this sensation