The impact of vitamin D3 intake on inflammatory markers in multiple sclerosis patients and their first-degree relatives

Abstract

Background & aims: In our previous study, a Seesaw model was proposed for the fluctuation of crucial anti- (IL-10) and pro-inflammatory (Il-6 & IL-17A) cytokines through vitamin D3. In this paper, however, it is intended to extend the mentioned model by assessing the expression mRNA levels of IL-27 and TGF-β1 as well as the changes of plasma levels of IL-27, TGF-β1, IL-17A, IL-10, and IL-6 after treatment by vitamin D3.

Method: Venous blood samples were drawn from Healthy Participants (HP, n = 25) and First-Degree Relative Participants (FDRP, n = 25) as control groups and Multiple Sclerosis Participants (MSP, n = 25) before and after eight weeks of supplementation with 50000 IU vitamin D3. The mRNA expression and plasma concentrations were gauged by using Real-Time PCR and ELISA assay, respectively.

Results: The mRNA surfaces of IL-27, as well as TGF-β1, were up-regulated. However, the plasma levels of TGF-β1, IL-17A, and IL-6 were significantly different among the three groups. In addition, the plasma levels of IL-27, TGF-β1, IL-10, IL-17A, and IL-6 significantly changed following the administration of vitamin D3.

Conclusion: The findings of this paper illustrate that anti-inflammatory cytokines could have a key role in immunomodulatory functions due to their anti-inflammatory functions. To conclude, this might contribute to preventing the pathophysiological process of MS. Also, the proposed model could be used as a preventive way on disposed people to multiple sclerosis, particularly in first degree relatives of these patients.

Fig 1. Enrollment and selection of participants allocated to groups by simple random sampling.

Fig 2. The outcome of IL-27 & TGF-β1 mRNA expression analysis.

Impacts of vitamin D₃ administration on mRNA expression of anti-inflammatory cytokines (n = 25 per group). (A-D) IL-27 and TGF-β1 mRNA expression surfaces of Multiple Sclerosis Participants (MSP), First Degree Relatives Participants (FDRP), and Healthy Participants (HP). In comparison, among groups, MSP, FDRP, and HP have been identified by A, B, and C, respectively. One-way ANOVA and then, post-hoc Tukey’s test, was applied. The data were then represented as mean ± standard deviation (SD), and * P<0.05 was considered as statistically significant between groups.

Fig 3. The outcome of IL-27, TGF-β1, IL-17A, IL-10 & IL-6 protein levels analysis.

Effects of vitamin D₃ administration on plasma concentrations of cytokines in Multiple Sclerosis Participants (MSP), First Degree Relatives Participants (FDRP), and Healthy Participants (HP) (n = 25 per group). One-way ANOVA and then, post-hoc Tukey’s test, was applied. We observed that supplementation with vitamin D₃ had significantly effect in changing plasma levels of IL-27, TGF-β1, IL-17A, IL-10 & IL-6 in MSP group (A), while, only the plasma levels of IL-6, IL-10 & IL-27 in FDRP group (B) and IL-17A & IL-6 in HP group (C) changed. Mean ± standard deviation (SD) and asterisk (*) represents the differences before and after supplementation, also, P<0.05 was considered as statistically significant between groups.

Fig 4. Seesaw model.

(A): When the sera level of vitamin D is sufficient, the anti-inflammatory state will come true. Thereby, at the first step, the expression levels of IL-27 and TGF-β1 augment. Then, the effectiveness of these cytokines has been represented separately by 1. negative feedback on the IL-17A expression, and 2. Positive feedback on the IL-10 expression as a major anti-inflammatory. After that, the pro-inflammatory state is prohibited. (B): Conversely, pro-inflammatory cytokines, especially IL-17A, increases during the deficiency level of vitamin D₃. IL-17A mediates BBB dysfunction (so, pro-inflammatory cytokines can cross the BBB) and induces secretion of IL-6 by BBB endothelial. However, after the production of IL-6 and in the presence of TGF-β1 in inflammation tissue, IL-6 has positive feedback on increasing IL-17A secretion, too. TGF-β1: Transforming Growth Factor-β1, BBB: Blood-Brain Barrier, IL: Interleukin.