0000000000217187
AUTHOR
Mikahela A. López-morales
Relaxant Effects of the Selective Estrogen Receptor Modulator, Bazedoxifene, and Estrogen Receptor Agonists in Isolated Rabbit Basilar Artery
We have previously shown that the selective estrogen receptor modulator, bazedoxifene, improves the consequences of ischemic stroke. Now we aimed to characterize the effects and mechanisms of action of bazedoxifene in cerebral arteries. Male rabbit isolated basilar arteries were used for isometric tension recording and quantitative polymerase chain reaction. Bazedoxifene relaxed cerebral arteries, as 17-β-estradiol, 4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol [estrogen receptor (ER) α agonist], and G1 [G protein-coupled ER (GPER) agonist] did it (4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol > bazedoxifene = G1 > 17-β-estradiol). 2,3-Bis(4-hydroxyphenyl)-propionitrile (E…
Emergent Uric Acid Treatment is Synergistic with Mechanical Recanalization in Improving Stroke Outcomes in Male and Female Rats.
Preclinical and clinical studies support a promising, albeit not definitive, neuroprotective effect of emergent uric acid (UA) administration in ischemic stroke. We assessed the effects of UA in an ischemic stroke model relevant to the current treatment paradigm of mechanical thrombectomy within the STAIR/RIGOR recommendations. A cohort of male and female Wistar rats was subjected to ischemic stroke with mechanical recanalization under physiological monitoring. The effects of transient middle cerebral artery occlusion (tMCAO) with adjunctive UA (IV, 16 mg/kg) or vehicle treatment were assessed at 24 h and 7 days. Outcomes included neurofunctional impairment, brain infarct (TTC staining, MRI…
Potassium channels contribute to the increased sensitivity of the rabbit carotid artery to hydrogen sulfide in diabetes
Abstract Hydrogen sulfide (H2S) is a potential endothelium-derived hyperpolarizing factor (EDHF) and adventitium- or adipocyte-derived relaxing factor (ADRF) which vasorelaxant action is mediated by potassium channels. H2S could also play an important role in the pathophysiology of diabetic cardiovascular complications. The present study has investigated the influence of alloxan-induced diabetes on the role of potassium channels mediating the relaxant response of the rabbit carotid artery to NaHS, a donor of H2S. NaHS (10−8-3 × 10−5 M) relaxed phenylephrine-precontracted carotid arteries, with higher potency in diabetic than in control rabbits. The selective blockers of potassium channels c…
The selective oestrogen receptor modulator, bazedoxifene, mimics the neuroprotective effect of 17β‐oestradiol in diabetic ischaemic stroke by modulating oestrogen receptor expression and the MAPK / ERK 1/2 signalling pathway
Because neuroprotection in stroke should be revisited in the era of recanalisation, the present study analysed the potential neuroprotective effect of the selective oestrogen receptor modulator, bazedoxifene acetate (BZA), in an animal model of diabetic ischaemic stroke that mimics thrombectomy combined with adjuvant administration of a putative neuroprotectant. Four weeks after induction of diabetes (40 mg kg-1 streptozotocin, i.p.), male Wistar rats were subjected to transient middle cerebral artery occlusion (intraluminal thread technique, 60 minutes) and assigned to one of three groups treated with either: vehicle, BZA (3 mg kg-1 day-1 , i.p.) or 17β-oestradiol (E2 ) (100 μg kg-1 day-…
Mechanisms involved in the increased sensitivity of the rabbit basilar artery to atrial natriuretic peptide in diabetes.
Atrial natriuretic peptide (ANP) is a vasodilator with significant regional differences and controversial effects in the cerebral circulation, a vascular bed particularly prone to diabetes-induced complications. The present study has investigated how alloxan-induced diabetes modifies the mechanisms involved in the response of the rabbit basilar artery to ANP. ANP (10(-12) -10(-7) M) relaxed precontracted basilar arteries, with higher potency in diabetic than in control rabbits. In arteries from both groups of animals, endothelium removal reduced ANP-induced relaxations. Inhibition of NO-synthesis attenuated ANP-induced relaxation but this attenuation was lower in diabetic than in control ra…
Molecular mechanisms underlying the neuroprotective role of atrial natriuretic peptide in experimental acute ischemic stroke
Abstract Along with its role in regulating blood pressure and fluid homeostasis, the natriuretic peptide system could be also part of an endogenous protective mechanism against brain damage. We aimed to assess the possibility that exogenous atrial natriuretic peptide (ANP) could protect against acute ischemic stroke, as well as the molecular mechanisms involved. Three groups of rats subjected to transient middle cerebral artery occlusion (tMCAO, intraluminal filament technique, 60 min) received intracerebroventricular vehicle, low-dose ANP (0.5 nmol) or high-dose ANP (2.5 nmol), at 30 min reperfusion. Neurofunctional condition, and brain infarct and edema volumes were measured at 24 h after…
The selective estrogen receptor modulator, bazedoxifene, reduces ischemic brain damage in male rat
While the estrogen treatment of stroke is under debate, selective estrogen receptor modulators (SERMs) arise as a promising alternative. We hypothesize that bazedoxifene (acetate, BZA), a third generation SERM approved for the treatment of postmenopausal osteoporosis, reduces ischemic brain damage in a rat model of transient focal cerebral ischemia. For comparative purposes, the neuroprotective effect of 17β-estradiol (E2) has also been assessed. Male Wistar rats underwent 60min middle cerebral artery occlusion (intraluminal thread technique), and grouped according to treatment: vehicle-, E2- and BZA-treated rats. Optimal plasma concentrations of E2 (45.6±7.8pg/ml) and BZA (20.7±2.1ng/ml) w…
Molecular mechanisms mediating the neuroprotective role of the selective estrogen receptor modulator, bazedoxifene, in acute ischemic stroke: A comparative study with 17β-estradiol
As the knowledge on the estrogenic system in the brain grows, the possibilities to modulate it in order to afford further neuroprotection in brain damaging disorders so do it. We have previously demonstrated the ability of the selective estrogen receptor modulator, bazedoxifene (BZA), to reduce experimental ischemic brain damage. The present study has been designed to gain insight into the molecular mechanisms involved in such a neuroprotective action by investigating: 1) stroke-induced apoptotic cell death; 2) expression of estrogen receptors (ER) ERα, ERβ and the G-protein coupled estrogen receptor (GPER); and 3) modulation of MAPK/ ERK1/2 and PI3K/Akt signaling pathways. For comparison, …