Multiple Sclerosis suppressed by an Ultraviolet wavelength not associated with Vitamin D (mice)
UVB radiation, vitamin D and multiple sclerosis.
Photochem Photobiol Sci. 2016 Dec 2.
DeLuca HF1, Plum L1.
1Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA. deluca@biochem.wisc.edu.
Acheson et al. (1960) observed an inverse relationship between sunlight exposure and the incidence of Multiple Sclerosis (MS). This led to the suggestion that increased levels of vitamin D caused by sunlight in some way suppresses MS. Further, super physiological doses of the metabolically active metabolite of vitamin D, i.e. 1α,25 dihydroxy vitamin D suppresses the animal model of MS i.e. experimental autoimmune encephalomyelitis (EAE).
However, this response was accompanied by hypercalcemia. Hypercalcemia itself can suppress EAE . The ability of 1,25(OH)2D3 to suppress EAE in mice is largely eliminated by a low calcium diet until hypercalcemia is induced by high doses of 1,25(OH)2D3 that causes mobilization of calcium from the skeleton. Of great importance is the finding that vitamin D deficiency prevents EAE, a finding dramatically opposite to the original hypothesis. Further, vitamin D receptor knock out animals do not develop EAE supporting the idea that vitamin D does not suppress EAE.
Upon revisiting the inverse relationship between light exposure and incidence of MS, a narrow band of light (300-315 nm) was discovered that prevents EAE without a change in serum levels of 25 hydroxy vitamin D (indicator of vitamin D status) . Clinical trials are underway to explore the possible use of this narrow band light as a treatment to stop the progression of MS, while biochemical studies are underway to evaluate the mechanism of action of the narrow band light.
PMID: 27910985 DOI: 10.1039/c6pp00308g