The impact of pericytes on the blood-brain barrier integrity depends critically on the pericyte differentiation stage.

The blood-brain barrier consists of the cerebral microvascular endothelium, pericytes, astrocytes and neurons. In this study we analyzed the differentiation stage dependent influence of primary porcine brain capillary pericytes on the barrier integrity of primary porcine brain capillary endothelial cells. At first, we were able to induce two distinct differentiation stages of the primary pericytes in vitro.

Methods to assess pericyte-endothelial cell interactions in a coculture model.

The blood-brain barrier (BBB) comprises the microvascular endothelial cells, pericytes, and astrocytes, which are connected by the extracellular matrix (ECM). Current BBB models focus solely on the microvascular endothelial cells which constitute a physical barrier by formation of tight junctions (TJs), while the impact of pericytes on barrier regulation is poorly understood. We established a coculture model from primary porcine brain capillary endothelial cells (PBCECs) and pericytes (PBCPs) to approach the in vivo situation.

Regulation of the blood-brain barrier integrity by pericytes via matrix metalloproteinases mediated activation of vascular endothelial growth factor in vitro.

The blood-brain barrier consists of the cerebral microvascular endothelium, pericytes, astrocytes, and neurons. In this study, we analyzed the influence of primary porcine brain capillary pericytes on the barrier integrity of primary porcine brain capillary endothelial cells in a species-consistent in vitro coculture model. We were able to show a barrier integrity-decreasing impact of pericytes by transendothelial electrical resistance (TEER) and (14)C-sucrose permeability measurements.

Metalloproteinase mediated occludin cleavage in the cerebral microcapillary endothelium under pathological conditions.

Reactive oxygen species (ROS) as well as matrix metalloproteinases (MMPs) induce modifications in the tight junction (TJ) protein occludin which is crucial for the blood-brain barrier (BBB) function. We investigated the role of ROS and MMPs in endothelial autoregulatory response on oxidative stress with respect to occludin and the BBB integrity. The ROS hydrogen peroxide (H(2)O(2)) was applied to our well-established BBB cell culture model based on primary porcine brain capillary endothelial cells (PBCEC).

Control of the blood-brain barrier by glucocorticoids and the cells of the neurovascular unit.

The blood-brain barrier is built up by endothelial cells lining the cerebral capillaries whereby the physical diffusion barrier is formed by tight junctions sealing the intercellular clefts. Chemical factors being released endogenously to the blood stream may regulate the barrier tightness. However, since tight junctions of the cerebral capillaries are more complex compared to those of other vessels, it becomes evident that the cells of the neurovascular unit play an important role in the induction and the maintenance of the barrier properties.