Orally Administered Calcitriol Reduced Inflammation in EB Mice

A lack of vitamin D is a potential key factor in epidermolysis bullosa acquisita (EBA), researchers have found. Using mouse models of the disease, they showed that orally administrating calcitriol, vitamin D’s active form, reduced disease severity and improved inflammation by regulating the immune system’s response.

The study, “Calcitriol treatment ameliorates inflammation and blistering in mouse models of epidermolysis bullosa acquisita,” was published in the Journal of Investigative Dermatology.

Vitamin D deficiency, or hypovitaminosis D, has gained attention as a potential factor contributing to autoimmune blistering skin disorders, but experimental evidence has been lacking.

Despite “the well-established use of vitamin D agents in different dermatologic diseases, information on clinical effects of this vitamin and the underlying immunomodulatory mode of action in autoimmune bullous diseases is generally lacking,” the research team wrote.

Researchers investigated how vitamin D may influence EBA by using two mouse models of the disease. They tested the effects of oral administration of calcitriol (1,25-dihydroxyvitamin D), the active form of vitamin D found in the body.

Mice treated with calcitriol showed a decrease in disease severity. The treatment also decreased the infiltration of a group of immune cells, called neutrophils, into the mice’s skin and impaired their activation.

The oral therapy had additional immunomodulatory effects including increasing the number of regulatory immune cells, which are responsible for keeping the immune system in check. It also reduced the number of pro-inflammatory cells, known as Th17 cells, which led to a reduction in the level of autoantibodies.

Researchers also analyzed total levels of 25-hydroxyvitamin D, the major circulating form of vitamin D, in EBA patients. In line with results from patients with other types of autoimmune skin diseases, the majority of EBA patients (73%) had lower levels of vitamin D. A total of 46% of patients had a deficiency of vitamin D, defined as levels lower than 20 ng/mL, and 27% had an insufficient vitamin D status (20-29 ng/mL).

Overall, “the results of this study support the potential introduction of supplementation with vitamin D derivatives or analogs in patients with EBA and related diseases due to its potent immunomodulatory action, although further interventional studies are needed to evaluate the beneficial effects of this treatment,” the team concluded.