Hyperglycemic conditions are prodromal to blood-brain barrier (BBB) impairment. The BBB comprises cerebral microvessel endothelial cells (CMECs) that are surrounded by astrocytic foot processes. Astrocytes express high levels of gap junction connexin 43 (Cx43), which play an important role in autocrine and paracrine signaling interactions that mediate gliovascular cross talk through secreted products. One of the key factors of the astrocytic “secretome” is vascular endothelial growth factor (VEGF), a potent angiogenic factor that can disrupt BBB integrity. We hypothesize that high-glucose conditions change the astrocytic expression of Cx43 and increase VEGF secretion leading to impairment of CMEC barrier properties in vitro and in vivo. Using coculture of neonatal rat astrocytes and CMEC, we mimic hyperglycemic conditions using high-glucose (HG) feeding media and show a significant decrease in Cx43 expression and the corresponding increase in secreted VEGF. This result was confirmed by the analyses of Cx43 and VEGF protein levels in the brain cortex samples from the type 2 diabetic rat (T2DN). To further characterize inducible changes in BBB, we measured transendothelial cell electrical resistance (TEER) and tight junction protein levels in cocultured conditioned astrocytes with isolated rat CMEC. The coculture monolayer’s integrity and permeability were significantly compromised by HG media exposure, which was indicated by decreased TEER without a change in tight junction protein levels in CMEC. Our study provides insight into gliovascular adaptations to increased glucose levels resulting in impaired cellular cross talk between astrocytes and CMEC, which could be one explanation for cerebral BBB disruption in diabetic conditions.

Objective Our study identified risk factors for the development of clinically identifiable catheter-associated thrombosis (CT). Study Design We performed a retrospective cohort study of neonates in whom a central catheter was present. A total of 1,475 catheters were identified in 766 patients during a 36-month study period. The odds ratio (OR) of thrombi formation in catheterized neonates was modeled using simple (single predictor) and multiple (multiple predictors) logistic regressions as well as simple and multiple Cox's proportional hazard models. Result The incidence of CT was 1.17 per 100 neonates. Unadjusted factors including age at insertion, history of surgery before or during line placement, cholestasis, femoral location, and line size significantly increased the OR or hazards ratio (HR) of developing thrombi formation. In multiple logistic and Cox's regression analyses, three factors continued to be significantly associated with OR or HR of thrombi formation: line size, femoral location, and cholestasis. Conclusion We conclude that clinically identifiable CT is rare in the neonatal population. Furthermore, catheter-specific characteristics are predictive for CT and require further investigation.