Adverse Effect of Cyclosporin A on Barrier Functions of Cerebral Microvascular Endothelial Cells After Hypoxia-reoxygenation Damage In Vitro

Abstract

Hypoxia and post-hypoxic reoxygenation induces disruption of the blood-brain barrier (BBB). Alterations of the BBB function after hypoxia/reoxygenation (H/R) injury remain unclear. Cyclosporin A (CsA), a potent immunosuppressant, induces neurotoxic effects by entering the brain, although the transport of CsA across the BBB is restricted by P-glycoprotein (P-gp), a multidrug efflux pump, and tight junctions of the brain capillary endothelial cells. The aim of this study was to evaluate whether the BBB after H/R damage is vulnerable to CsA-induced BBB dysfunction. We attempted to establish a pathophysiological BBB model with immortalized mouse brain capillary endothelial (MBEC4) cells. The effects of CsA on permeability and P-gp activity of the MBEC4 cells were then examined. Exposure to hypoxia for 4 h and reoxygenation for 1 h (H/R (4 h/1 h)) produced a significant decrease in P-gp function of MBEC4 cells, without changing cell viability and permeability for sodium fluorescein and Evan's blue-albumin at 7 days after H/R (4 h/1 h). CsA-induced hyperpermeability and P-gp dysfunction in MBEC4 monolayers at 7 days after H/R (4 h/1 h) were exacerbated. The possibility that CsA penetrates the BBB with incomplete functions in the vicinity of cerebral infarcts to induce neurotoxicity has to be considered.

Interleukin-25 Expressed by Brain Capillary Endothelial Cells Maintains Blood-Brain Barrier Function in a Protein Kinase Cϵ-dependent Manner

“…BBB Permeability and CD4 ϩ T Cell Transmigration Assay-The permeability of MBEC4 and primary BCEC monolayers was evaluated using the permeability marker, Evan's blue albumin (EBA), as described previously (32) and by measuring transendothelial electrical resistance (TER). Confluent monolayers of MBEC4 cells on the Transwell inserts (3-m pore size) were incubated with or without 50 ng/ml TNF-␣ and 50 ng/ml IL-25 for 24 h. The monolayers were then washed with assay buffer (118 mM NaCl, 4.7 mM KCl, 1.3 mM CaCl 2 , 1.2 mM MgCl 2 , 1.0 mM NaH 2 PO 4 , 25 mM NaHCO 3 , and 11 mM D-glucose (pH 7.4)).…”

Recovery of Motor Spontaneous Activity After Intranasal Delivery of Human Recombinant Erythropoietin in a Focal Brain Hypoxia Model Induced by CoCl2 in Rats

“…It was also demonstrated that MDR-1 gene overexpression could cause an impairment of brain hypoxia treatment with conventional drugs (Dohgu et al 2007;Xiao-Dong et al 2008). In this investigation, overexpression of both Epo-R and MDR-1 genes were documented at the same type of cells, and a successful treatment with rHu-Epo was also observed, suggesting that intranasal delivery of rHu-Epo could be an interesting approach in the treatment of cerebral hypoxia avoiding both (a) pharmacoresistant phenotype depending on MDR-1 expression and (b) peripheral adverse effects of erythropoiesis stimulation.…”

Tissue Plasminogen Activator Enhances the Hypoxia/reoxygenation-induced Impairment of the Blood–brain Barrier in a Primary Culture of Rat Brain Endothelial Cells

“…Other in vitro studies have demonstrated that hypoxia with reoxygenation increases endothelial cell permeability (Utepbergenov et al 1998;Dohgu et al 2007;Nishioku et al 2007). Fig.…”