Effects of 25-OH vitamin D supplementation on mesenchymal stromal cells in an animal model of Systemic Lupus Erythematosus (SLE)

Background. 25OH Vitamin D (25-OH-D3) is a fat-soluble steroid-derived molecule involved in the calcium homeostasis. Low levels of 25-OH-D3 are commonly found in patients with systemic lupus erythematosus (SLE) and have been correlated to higher disease activity and severity. Several recent studies have demonstrated that high dose Vitamin D may influence several aspects of the innate and adaptative immune response and some authors hypothesized that high dose 25-OH-D3 may have a role in the treatment of SLE. Despite these observations, the immunomodulatory effect of high dose 25-OH-D3 in vivo still needs to be demonstrated. Purpose: The aim of our study was to identify the effect of 25-OH-D3 on proteinuria, survival and renal biopsy in New Zealand Black/White F1 mice (NZ), that develop a disease very similar to human SLE nephritis. Methods. We administered to 20 NZ mice a diet enriched with high dose 25-OH-D3 10.000 UI/Kg starting from 8 weeks of age. Mice were divided in 7 experimental groups (5 mice each). The first group was sacrificed before the start of the treatment (8 week of age), three groups were treated (treated mice – TM) with 25-OH-D3 and sacrificed at 16, 26 and 36 weeks of age. Other three groups were enrolled as controls and sacrificed at 16, 26 and 36 weeks of age respectively (untreated mice – UM). The parameters collected included: total urinary protein and kidney histology for the evaluation of lupus nephritis (LN): glomerulonephritis, interstitial nephritis and vascular lesions according to a 5 points scale to obtain a total score (ranging from 0 to 12). Additionally the study of mesenchymal stromal cells proliferation has been studied.