Vitamin D supplementation in progressive MS should be medically supervised

Research involving a mouse model of progressive MS may indicate that the short-term positive effects of high-dose vitamin D supplementation outweigh the negative (i.e. observed increased microglial activation and neuronal loss). The results underline the need for medically supervised vitamin D supplementation in progressive MS, accompanied by regular monitoring.

The use of vitamin D supplementation in patients with MS is widespread. While high-dose vitamin D has been associated with adverse effects, such as kidney injury and hypercalcaemia, moderate dosages of vitamin D have been found to reduce brain pathology in mice [1].

Dr Michaela Haindl (Medical University of Graz, Austria) and colleagues studied the effects of intermediate-dose vitamin D (400 IU/week) compared with high-dose vitamin D (400 IU/day) in 29 rats [2]. They measured myelin preservation and microglial activation by means of proteolipid protein (PLP) and ionised calcium-binding adaptor molecule 1 (Iba1) immunohistochemistry, respectively.

Intermediate-dose vitamin D was associated with preservation of PLP on the contralateral side on day 15, while high-dose vitamin D showed preservation of PLP on both ipsilateral and contralateral sides. However, there was no significant difference in PLP preservation between the 2 dose groups. PLP preservation on day 30 followed a similar pattern. Conversely, microglial activation was significantly higher in the high-dose vitamin D group compared with the intermediate-dose group, both on day 15 and day 30. In additional analyses, a significant reduction in apoptotic cells, marked by caspase-3, was observed with high-dose vitamin D on day 15. Serum NfL levels were lower with higher vitamin D supplementation on day 15 (P=0.004).

The authors concluded that high-dose vitamin D seemed to have a negative effect on microglia and led to an increased activation. Interestingly, high-dose vitamin D seemed to be associated with lower numbers of apoptotic cells but also with increased neuronal loss. Thus, vitamin D supplementation in patients with progressive MS should be carefully monitored.

1. Haindl MT, et al. Nutrients. 2023;15(15):3309.
2. Haindl MT, et al. High dose vitamin D supplementation leads to increased microglial activation and neuronal loss in an animal model of progressive multiple sclerosis. Poster P648, ECTRIMS 2024, 18–20 October 2024, Copenhagen, Denmark.

 

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Posted on 18 November 202425 November 2024