Alanis Dávila-Santiago¹, Alanis N. Rivera-Ramos¹, Luis A. Rojas-Colón¹, David E. Rivera-Ponte², Jadier Colón-Vázquez², Miguel P. Méndez-González^1,2
1 Department of Natural Sciences at University of Puerto Rico, Aguadilla, 2 Department of Biochemistry at Universidad Central del Caribe, School of Medicine

Introduction: Diabetic patients with high blood glucose levels are at increased risk of suffering from a neurological disorder known as epilepsy. Previous studies have shown that high glucose levels can induce the secretion of inflammatory cytokines from brain cells such as astrocytes. Pro-inflammatory cytokines can downregulate the expression of the inwardly rectifying potassium channel 4.1 (Kir4.1), increasing seizure susceptibility. Moreover, during seizures, there is an increase in pro-inflammatory cytokines that could further exacerbate the pathology. The objective of this study is to observe if chronic high glucose conditions affect the expression of inflammatory cytokines in astrocytes.

Methodology: Primary mixed cultures of astrocytes and microglia were obtained from the neocortex of 1–2 day-old rats. The cells were cultivated in 2 experimental groups. One group was plated in high glucose (25mM) DMEM and a second group was plated in normal glucose (5mM) DMEM. The medium was exchanged every 4 days, and at about 12 days, leucine methyl ester (pH 7.4) in 50-75 mM was used to treat the mixed glial cultures to kill microglia. In 1 mL of supernatant, cytokine expression was measured using the RayBio Rat Cytokine Antibody Array, which can detect 34 rat proteins.

Results: We found that astrocytes grown in hyperglycemic conditions have a higher expression of pro-inflammatory cytokines (e.g. CINC-3, and TNF-α) as well as anti-inflammatory cytokines (e.g. CNTF) in comparison to normal glucose control conditions.

Conclusion: These results demonstrate that astrocytes cultured under hyperglycemic conditions regulate pro-inflammatory and anti- inflammatory cytokine secretion, which could impact seizure outcomes. In the future we seek to study the effect of upregulated inflammatory cytokines on astrocytes and study the effect of metformin on inflammatory cytokine expression by astrocytes in hyperglycemic conditions.

Acknowledgements: We would like to acknowledge following funding sources: NIHP20GM103475-19, American Diabetes Association 1-19-IBS-300, NIH-NINDSR15-NS116478, NIH- NINDSSC2NS124907, NIH-NINDSNS124907, NIH-NIMHDG12MD007583, and NSF grant no. 2122203.