eprosartan and Cerebrovascular-Disorders

Selective blockade of the angiotensin II AT1 receptor represents a novel mechanism for interrupting the renin-angiotensin system without altering the potential benefits of AT2 receptor stimulation. This selective inhibition produces none of the disadvantages associated with reduced bradykinin metabolism and angiotensin II generated by non-angiotensin-converting enzyme pathways. Eprosartan is a potent (1.4 nmol/L) AT1 receptor antagonist that competitively blocks angiotensin II-induced vascular contraction. In various animal models of disease, including hypertension and stroke, eprosartan is effective in reducing disease progression. Eprosartan also has sympathoinhibitory activity, as demonstrated by an inhibition of the pressor responses induced by activation of sympathetic outflow through spinal cord stimulation in pithed rats. In contrast, some of the other angiotensin II receptor antagonists, such as losartan, at equivalent angiotensin II blocking doses, have no effect on sympathetic nervous system activity. Because eprosartan can inhibit both the direct effects of angiotensin II as well as the indirect effects that are mediated by enhanced sympathetic neurotransmission, this may represent an important advance in the treatment of elevated systolic blood pressure.

Topics: Acrylates; Angiotensin II; Angiotensin Receptor Antagonists; Animals; Antihypertensive Agents; Blood Pressure; Cerebrovascular Disorders; Disease Models, Animal; Humans; Hypertension; Imidazoles; Rats; Receptors, Angiotensin; Renin-Angiotensin System; Sympathetic Nervous System; Thiophenes

Eprosartan (EPRO), an angiotensin receptor type-1 (AT-1) blocker, exhibited neuroprotective activities in ischemic stroke resulting from focal cerebral ischemia in rats. The current study aimed to clarify the neuroprotective role of EPRO in middle carotid artery occlusion (MCAO)-induced ischemic stroke in rats. Fifty-six male Wistar rats were divided into four groups (n = 14 per group): sham-operated group, sham receiving EPRO (60 mg/kg/day, po) group, ischemia-reperfusion (IR) group, and IR receiving EPRO (60 mg/kg/day, po) group. MCAO led to a remarkable impairment in motor function together with stimulation of inflammatory and apoptotic pathways in the hippocampus of rats. After MCAO, the AT1 receptor in the brain was stimulated, resulting in activation of Janus kinase 2/signal transducers and activators of transcription 3 signaling generating more neuroinflammatory milieu and destructive actions on the hippocampus. Augmentation of caspase-3 level by MCAO enhanced neuronal apoptosis synchronized with neurodegenerative effects of oxidative stress biomarkers. Pretreatment with EPRO opposed motor impairment and decreased oxidative and apoptotic mediators in the hippocampus of rats. The anti-inflammatory activity of EPRO was revealed by downregulation of nuclear factor-kappa B and tumor necrosis factor-β levels and (C-X-C motif) ligand 1 messenger RNA (mRNA) expression. Moreover, the study confirmed the role of EPRO against a unique pathway of hypoxia-inducible factor-1α and its subsequent inflammatory mediators. Furthermore, upregulation of caveolin-1 mRNA level was also observed along with decreased oxidative stress marker levels and brain edema. Therefore, EPRO showed neuroprotective effects in MCAO-induced cerebral ischemia in rats via attenuation of oxidative, apoptotic, and inflammatory pathways.

Topics: Acrylates; Animals; Brain; Cerebrovascular Disorders; Imidazoles; Male; Nerve Tissue Proteins; Neuroprotective Agents; Rats; Rats, Wistar; Reperfusion Injury; Signal Transduction; Thiophenes

Moderate elevations in blood pressure translate to significant increases in cardiovascular and cerebro vascular risk. Beneficially, this relationship allows small decreases in blood pressure to be associated with risk reduction. Both the renin-angiotensin system and the sympathetic nervous system are involved in hypertension, hence targeting these systems is likely to be of benefit in the treatment of hypertension. Angiotensin II type 1 receptor blockers (ARBs) are used for controlling blood pressure and treating heart failure in a broad range of patients, including those with diabetes and the elderly. Not only have ARBs shown good efficacy and tolerability, they also appear to have a protective effect that goes beyond that expected from the reduction of blood pressure. The ARB eprosartan is a nonbiphenyl nontetrazole angiotensin II type 1 receptor (AT1) antagonist, which acts to decrease total peripheral resistance. Eprosartan acts at vascular AT1 receptors (postsynaptically) and at presynaptic AT1 receptors, where it inhibits noradrenaline release. In clinical studies, eprosartan has been shown to significantly reduce cardiovascular and cerebrovascular events, whilst avoiding the persistent cough that commonly occurs with the use of angiotensin-converting enzyme inhibitors. Eprosartan can also be differentiated from other ARBs due to its noradrenergic effects, which other ARBs used at therapeutic doses do not possess. Eprosartan, therefore, represents a useful therapeutic option in the management of patients with hypertension, including those with a history of stroke or with co-morbid type 2 diabetes mellitus.

Topics: Acrylates; Aged; Aged, 80 and over; Angiotensin II Type 1 Receptor Blockers; Antihypertensive Agents; Cardiovascular Diseases; Cerebrovascular Disorders; Humans; Hypertension; Imidazoles; Middle Aged; Risk; Thiophenes