The Presence of the Endocannabinoid System in an In Vitro Model of Gorham-Stout Disease and Its Possible Role in the Pathogenesis

Gorham-Stout syndrome (GSD), also known as disappearing bone disease, is an extremely rare bone disorder, characterized by a huge bone loss, which is followed by a lack of new matrix deposition and an excessive proliferation of both blood vessels and lymphatics. Unfortunately, the biological causes of GSD are still unknown. Recent studies that have tried to understand the etiopathogenesis of GSD have been principally focused on the vascular and osteoclastogenic aspects, not considering the possibility of a lack of osteoblast function. Nowadays, a diagnosis is still difficult, and is often made by exclusion of the presence of other pathologies, as well as on radiological evidence, and finally confirmed by histological examination. Treatment also remains a critical issue for clinicians today, who mostly try to control the progression of the disease. Over the last two decades, clear evidence has emerged that the endocannabinoid system plays an important role in bone metabolism, leading scientists to hypothesize that it could be involved in physiological and pathological bone processes. In this work, we analyzed the presence of the ES in a primary cell line of human mesenchymal stem cells derived from a GSD patient for the first time, to understand if and how this complex network may play a role in the pathogenesis of the syndrome. Our preliminary results demonstrated that the ES is also present in the pathological tissue. Moreover, the qRT-PCR analysis showed an altered expression of the different ES components (i.e., CNR1, CNR2, TRPV1, and GPR55). We observed an upregulation of CNR1 and TRPV1 expression, while the opposite trend was noticed for CNR2 and GPR55 expression. Thus, these results could lead us to speculate that possible deregulation of the ES may play an important role in the lack of bone regeneration in GSD patients. However, further studies will be necessary to confirm the role of the ES in the progression of GSD and understand whether the natural components of Cannabis Sativa could play a therapeutic role in the treatment of the disease.