Prevention of autoimmune diabetes in NOD mice by 1,25 dihydroxyvitamin D 3

Abstract

Summary 1,25 dihydroxyvitamin D3, the active form of vitamin D, has immunomodulatory properties in vitro and in vivo. We report that treatment with 1,25 dihydroxyvitamin 03 (5 gg/kg on alternate days) prevents the development of clinical diabetes in NOD mice, an animal model of human autoimmune diabetes. Diabetes incidence in female NOD mice at the age of 200 days was reduced to 8 % in the 1,25 dihydroxyvitamin D treated group vs 56% in the control group (p < 0.0001). In parallel, treatment with 1,25 dihydroxyvitamin D 3 resulted in a complete normalisation of the capacity to induce suppressor mechanisms in an autologous MLR, which is severely depressed in control NOD mice. The existence of such suppressor ceils was confirmed in transfer experiments, whereby cotransfer of splenocytes from 1,25 dihydroxyvitamin D3 treated NOD mice prevented diabetes transfer by splenocytes from diabetic NOD mice into irradiated, 6-8-week-old male NOD mice. Other known immune defects of the NOD mice, such as defective natural killer cell killing of YAC-1 targets and defective thymocyte activation by anti-CD3 were not corrected. The pharmacological doses of 1,25 dihydroxyvitamin D3 were universally well tolerated as reflected by a normal weight gain of the mice. Serum calcium was increased (2.5+0.2 vs 2.2 + 0.2 mmol/1 in the control group,p < 0.005), whereas osteocalcin levels nearly doubled and bone calcium content was halved. These findings show that 1,25 dihydroxyvitamin D3 can prevent diabetes in NOD mice, probably through the correction of their defective suppressor function. [Diabetologia (1994) 37: 552-558]

1,25-Dihydroxyvitamin D3 restores sensitivity to cyclophosphamide-induced apoptosis in non-obese diabetic (NOD) mice and protects against diabetes

“…Diabetes and insulitis were evaluated as described previously [2]. Briefly, mice were weighed weekly and glucosuria was tested 3 times a week starting from 1 week before CY administration using Clinistix (Bayer Diagnostics, Basingstoke, UK).…”

“…Pancreases were removed and fixed in Bouin's solution. Haematoxylin and eosin-stained serial sections were evaluated for insulitis by two independent investigators as described previously [2]. Any degree of lymphocytic infiltration of the islets was scored as positive.…”

“…Naive 6-8-week-old male NOD mice were sublethally (7·5 Gy) irradiated and received, 48 h later, 20 × 10 6 splenocytes intravenously obtained from overtly diabetic NOD mice [2]. In co-transfer experiments, 20 × 10 6 splenocytes from test mice were injected intravenously, 24 h before the transfer of the diabetogenic cells.…”

“…4b): apoptosis was detected in 17% in NOD mice compared with 35% in C57Bl/6 mice (P < 0·00001). Interestingly, treatment with 1,25(OH) 2 appeared from a trend to a lower percentage of splenocytes surviving the CY injection (46% remaining cells in 1,25(OH) 2 D 3 -treated mice versus 55% in control NOD mice, NS, Fig. 4a), but especially from a significant difference as demonstrated by the more reliable TUNEL technique (25% apoptosis in 1,25(OH) 2 D 3 -treated mice versus 17% in control NOD mice, P < 0·001, Fig.…”

“…In previous work we have demonstrated that NOD mice treated with 1,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ) were protected against insulitis and diabetes [1,2]. This protection was achieved without signs of systemic immunosuppression and was associated with a restoration of the defective immune regulator system of the NOD mice.…”