Table 6.

Summary of factors related to hypertension that promote BBB disruption and risk of HT.

Marker	Effect on BBB/consequences/contribution to risk of HT	References (for further reading)
Changes to the immune system and response
Elevated levels of proinflammatory cytokines as TNF, IL-6, MCP-1, and sICAM-1 in the vasculature	Impact endothelial cell ability to regulate. Leukocyte interaction and infiltration, disruption of BBB	(80)
Response to Angiotensin II due to chronic hypertension
Increased MMP-9 and MMP-2	Activated by the renin-angiotensin system in the vasculature, leading to vessel remodeling and disruption of the BBB	(81)
Increase in serum PAI-1	Activated by Angiotensin II, interferes with the tPa/alteplase degradation	(67)
Increased ROS through NADPH oxidases	Macrophages in response to Angiotensin II Additionally, acute hypertension may attenuate the ability to cope with ROS	(82)
Mechanical cellular changes due to chronic hypertension
Remodeling of microvasculature: Decreased lumen diameter, increased vascular resistance, increased wall to lumen diameter.	Decreased endothelial cell function and reduced autoregulation ability	(80)

BBB, Blood brain barrier; IL, interleukin; MCP-1, monocyte chemoattractant protein 1; NADPH, Nicotinamide adenine dinucleotide phosphate; PAI-1, plasminogen activator inhibitor-1; ROS, reactive oxygen species; sICAM, soluble intercellular adhesion molecule; TNF, tumor necrosis factor; tPa, tissue plasminogen activator.