Influence of Omega 3 and 6 Fatty Acids on Human Meibomian Gland Epithelial Cells.

PURPOSE

Oral supplementation with omega 3 (ω-3) and/or 6 (ω-6) fatty acids (FAs) has been reported to alleviate the signs and symptoms of dry eye disease and to improve the expressibility and quality of meibum, in patients with meibomian gland dysfunction. We tested our hypothesis that these FA effects may reflect a direct FA action on human meibomian gland epithelial cells.

METHODS

Immortalized human meibomian gland epithelial cells (IHMGECs) were cultured with ω-3, ω-6, or both FAs together for up to 7 days in the presence or absence of serum. After FA exposure, cells were analyzed for lipid expression, lysosome content, and proliferative ability.

RESULTS

Our research shows that ω-3 and ω-6 stimulate the accumulation of small neutral lipid-containing vesicles, but not lysosomes, in IHMGECs. This vesicular effect was associated with a 2.4- to 3.7-fold increase in the cellular content of triglycerides after ω-3 and ω-6 treatment, respectively. The combination of both FAs together also enhanced triglyceride levels. Of interest, culture of IHMGECs with ω-3 and azithromycin, a known inducer of IHMGEC differentiation, led to a significantly greater amount of total neutral lipids, relative to that found with azithromycin alone. Cellular exposure to the FAs did not alter the expression of free or esterified cholesterol, or phospholipids. Further, these FAs, alone or together, prevented the proliferation of IHMGECs in serum-free, but not serum-containing, media.

CONCLUSIONS

Our findings support our hypothesis and demonstrate that ω-3 and ω-6 can act directly on IHMGECs to influence the quality and quantity of intracellular lipids.