engleski

Stroke as a consequence of hypertension

Hypertension is the most important modifiable risk factor for stroke and has been reported in about 64% of patients with stroke. Hypertension also worsens stroke prognosis since patients with pre-existing hypertension have less salvageable tissue in comparison to normotensive patients. Chronic mechanical stress on cerebral arteries caused by hypertension, endothelial dysfunction and decreased NO have negative consequences for the brain as these conditions lead to decreased autoregulatory capacity. Autoregulation ensures relatively constant cerebral blood flow over a range of BP changes. Hypertension increases blood-brain barrier permeability via reactive oxygen species and lowers its capability to regulate homeostasis. Hypertension is linked to high leves of angiotensin II in the brain and circulation which causes oxidative stress by increasing superoxide production and impairing the normal vasodilatory effect of NO. Endothelin-1 is also a vasoconstrictor synthesized by endothelial cells in the cerebral vasculature. Under normal physiological conditions, NO inhibits endothelin-1 release. However, in conditions such as hypertension, NO is decreased, endothelin-1 release is enhanced and thus vasoconstriction is also increased.

Hypertension, stroke, angiotensin II, endothelin-1

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