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Womens Health

Women's Health - Poster Session E

Poster L22 - The impacts of estradiol on hyperglycemic cell barriers of the retina

Saturday, October 26, 2024
10:00 AM – 11:00 AM EST
Location: Exhibit Hall E, F & G

Introduction:  Millions of people with diabetes are at risk of developing diabetic retinopathy (DR), a disease of progressive vision loss as a result of degradation of the inner blood-retinal barrier (iBRB) and improper vascular growth into the retina. There are limited treatment options for DR and no preventative care beyond controlling blood glucose concentrations. Hyperglycemia in individuals with diabetes increases the formation of advanced glycation end products (AGEs), inflammatory molecules which are suggested to contribute to the breakdown of the iBRB. Additionally, hormonal changes in females due to menopause have been suggested to increase occurrence of DR. The hormone estradiol (E2) drops from 30-400 ng/mL to 0-30ng/mL in human females due to menopause. The addition of estradiol has previously demonstrated neuroprotective properties in mammalian cell culture, suggesting hormone therapy may be leveraged to prevent iBRB degradation in postmenopausal women with diabetes.

Materials and

Methods:  Rat Primary Retinal Microvascular Endothelial Cells (RA6065) (Cell Biologics) were cultured in unmodified endothelial growth media (Cell Biologics), endothelial growth media containing AGEs (Millipore Sigma), and endothelial growth media containing AGEs and estradiol (E2 + AGEs) at physiologically relevant concentrations for seven days before seeding in 6.5 mm transwell inserts with 0.4 µm pores. The transwell inserts were coated with rat fibronectin (Sigma Aldrich) and rat collagen type I (Sigma Life Sciences) and cultivated into an endothelial cell monolayer. Transepithelial/transendothelial electrical resistance (TEER) measurements were collected over a four day period to evaluate the effects of chronic hyperglycemic AGEs and E2 treatment on cell barrier integrity.

Results, Conclusions, and Discussions: Between hours 1 and 24 seeded endothelial cells formed a monolayer barrier, with TEER values increasing until stabilizing at 18 hours (Figure 1A). After 24 hours, there was a significant difference in resistance between unconditioned and AGE conditioned endothelial cell monolayers (p=0.0011), and between the unconditioned and E2 + AGE conditioned endothelial cell monolayers (p < 0.0001) (Figures 1). Notably, there is no significant difference between AGE and E2 + AGE conditions at hours 24 and 48. At hour 72, there is no longer any significant difference between unconditioned endothelial cell monolayer resistance and the monolayer treated with E2 + AGEs (Figure 1B). Instead, there was a significant difference between monolayers treated with AGEs and those treated with E2+AGEs (p < 0.0077). Despite vision loss from diabetic retinopathy affecting many people, there remains limited preventive and treatment options available. These results indicate that estradiol has the potential to aid in the neuroprotection and recovery of endothelial cell barriers, exhibited by the TEER data after 72 hours of E2 treatment. Barrier integrity was recovered in the E2+AGEs condition and demonstrated no significant difference with the unconditioned endothelial cell monolayer. The AGE conditioned monolayer did not recover barrier integrity, and displayed significantly lower barrier resistance than the E2+AGEs conditioned monolayer. This suggests hormone therapy is a possible form of preventative care or treatment for postmenopausal women with diabetic retinopathy. Future research will incorporate additional relevant cell components to create a more comprehensive in vitro model of the iBRB to further test the effects of estradiol on the recovery and maintenance of cell barrier integrity.

Acknowledgements (Optional):