Aim: 1a,25-dihydroxyvitaminD3 (VD) is a steroid hormone that plays a key role in calcium homeostasis and in several tissues. For example it has been demonstrated that VD can induce an increase in nitric oxide (NO) production in endothelial cells (EC; Molinari C, Cell Physiol Biochem 27:661,2011). Since it has been shown that NO stimulates proliferation, migration and differentiation of EC to form new blood vessels (Fukumura D, Nat Rev Cancer 6:521,2006), our aim was to test if VD was able to induce proliferation and migration in EC.

Methods: Porcine aortic EC were starved for 24h in 1% FCS, stimulated for 24h with VD (1 to 100 nM), fixed, stained with 1% toluidine and counted by optical microscopy. Migration in a 3D matrix was studied using an anionic hydrogel (~1 cm² surface, gelatin-PLGA; Epinova Biotech, Novara) and MMP-2 production. Hydrogel samples were layered onto 70-80% confluent EC layer and observed after 1 week of VD stimulation (1 to 100 nM) to score cells migrated inside the 3D structure, while MMP-2 activity was tested in conditioned cell medium using gelatin zymography.

Results: VD 10 nM induced a significant increase of cellular density (+64.5%; p<0.0001) compared to control samples, while VD increased cell migration into 3D matrix at every concentration along with MMP-2 expression.

Conclusion: VD can promote both endothelial cells proliferation and migration in a 3D matrix. These findings cast new light on the role of VD in the angiogenetic process.