Curcumin modulates inflammatory responses in peripheral blood mononuclear cells from women with gestational diabetes mellitus

Introduction:
Curcumin is a multi-functional component with anti-inflammatory and immunomodulatory properties. Unregulated immune responses may be a causative factor in the development of gestational diabetes mellitus (GDM). This study investigated the effect and mechanisms of curcumin on regulatory T cells/Th17 axis, and secretion of related cytokines (interleukin [IL]-17A, IL-6, and IL-10) in peripheral blood mononuclear cells (PBMCs) of healthy women and women with GDM.

Material and methods:
This research involved in vitro experiments to evaluate the influence of curcumin on PBMCs; none of the subjects were taking any curcumin supplementation. Flow cytometry and ELISA were used in this study. Curcumin (1 µM, for 72 hours) treatment reduced the frequency of Th17 cells and the levels of related cytokines (IL-6, and IL-17) in women with GDM.

Results:
The percentage of Th17 cells decreased after treatment with curcumin relative to untreated cells in the GDM group (p = 0.04). Curcumin reduced the IL-17A level in the GDM group (p = 0.01). Curcumin treatment reduced the IL-6 level only in the GDM group (p = 0.02). In the presence of curcumin, the IL-10 level in the supernatants of cell culture was significantly higher in the GDM group compared to the negative control (p = 0.0008).

Conclusions:
The findings of the present study showed that curcumin modulated the immune responses via balancing of Treg/Th17 in women with GDM. Curcumin increased the level of IL-10, an anti-inflammatory cytokine, whereas it decreased the level of IL-6, which is related to the differentiation of Th17 cells. Curcumin treatment decreased the expression of IL-17A, the main secretory cytokine of Th17 cells. In conclusion, curcumin may act as an immunomodulator component in GDM by balancing the Th17/Treg axis.