Vitamin E is a MIF Inhibitor

Macrophage migration inhibitory factor (MIF) is known to contribute to the pathogenesis of inflammatory hyperalgesia and neuropathic pain. Prior studies have shown that Vitamin E treatment is associated with attenuated hyperalgesia and reduced neuropathic pain in rodents. Given these observations, we investigated the possibility that Vitamin E is a MIF inhibitor. Dopachrome tautomerase assays revealed that Vitamin E inhibits the enzymatic activity of purified human recombinant MIF (rhMIF) in a dose-dependent manner (45%, 74%, 92% and 100% inhibition at 3, 10, 30 and 100μM, respectively). Cell-free ELISA based assays showed that Vitamin E binds onto rhMIF thereby blocking its recognition (48% inhibition at 100μM). Circular dichroism studies indicated the Vitamin E has a strong affinity to bind to rhMIF (binding constant 19.52±1.4μM). In silico studies demonstrated that Vitamin E docks well in the active site of MIF with the long aliphatic chain of Vitamin E exhibiting strong van der Waals interactions with MIF. Most importantly, human cell-based assays revealed that Vitamin E significantly inhibits rhMIF-induced production of pro-inflammatory cytokines in a dose-dependent manner (77%, 80%, and 96% inhibition of IL-6 production, respectively, at 10, 30 and 100μM). Taken together, these results demonstrate that Vitamin E inhibits not only the enzymatic activity of MIF but more importantly the biological function of MIF. Our findings suggest that Vitamin E may be attenuating hyperalgesia and reducing neuropathic pain at least in part by inhibiting MIF activity.

Expression of IL-12 and T helper cell 1 cytokines in the fluid of paranasal sinus mucoceles

OBJECTIVE

The objective of this study was to assess the expression of regulatory cytokines and T helper cell (Th)1/Th2 cytokines in paranasal sinus mucoceles.

MATERIALS AND METHODS

Fluid samples of 12 paranasal sinus mucoceles were assessed by enzyme-linked immunosorbent assay for concentrations of regulatory cytokines (interleukin [IL]-10 and IL-12), Th1 cytokines (IL-2 and interferon gamma), and Th2 cytokines (IL-4 and IL-5).

RESULTS

IL-12 was detected in all samples, whereas IL-10 was detected in only one case. The concentration of IL-12 tended to correlate with that of interferon gamma and was significantly and positively correlated with that of IL-2.

CONCLUSIONS

Th1 cytokines and the Th1 regulatory cytokine IL-12, but not IL-10, potentially play a key role in the pathogenesis of paranasal sinus mucoceles. Together with our recent report showing that lipopolysaccharide is highly detected in mucocele fluid, the data from this study suggest that the Th1 response induced by lipopolysaccharide may affect the immunological inflammation in the epithelium of paranasal sinus mucoceles.