Hypothesis: Astrocyte foot processes detachment from the neurovascular unit in female diabetic mice may impair modulation of information processing—six degrees of separation

Abstract

Astrocytes via their foot processes (ACfp) are specialized connecting cells, and they structurally connect the neurovascular unit (NVU) mural cells to neurons. Astrocytes provide homeostatic mechanisms for structural connections and provide communication between the NVU and regional neurons for functional hyperemia in regions of increased neuronal activity (neurovascular coupling). Previously, our group has demonstrated a detachment, separation, and retraction of ACfp in diabetic db/db females (DBC). It was hypothesized that a loss of adherent ACfp/NVU could result in the known impaired cognition in DBC. Additionally hypothesized was that empagliflozin treatment could protect DBC ACfp/NVU remodeling. This study demonstrates a significant loss of ACfp/NVU numbers in DBC and a protection of this loss by empagliflozin treatment (DBE). The number of intact ACfp/NVU was 6.45 ± 1.1 in control heterozygous (CKC) vs. 1.88 ± 0.72 in DBC (p < 0.05) and 5.86 ± 0.88 in DBE vs. DBC (p < 0.05) by visually hand-counting the capillary NVUs (22 in CKC, 25 in DBC, and 22 in DBE). These findings suggest that empagliflozin provides neuroprotection via the prevention of ACfp separation in DBE as compared to diabetic DBC. Furthermore, a loss of ACfp/NVU numbers in DBC may correspond with a negative modulation of informational processing, and the protection of ACfp/NVU numbers could provide a protective modulation in DBE models