Carmen Capone - Academia.edu (original) (raw)

Papers by Carmen Capone

Cerebral small vessel disease (SVD) is a leading cause of stroke and dementia.

Annals of neurology, Jan 9, 2015

CADASIL is a genetic paradigm of cerebral small vessel disease caused by NOTCH3 mutations that st... more CADASIL is a genetic paradigm of cerebral small vessel disease caused by NOTCH3 mutations that stereotypically lead to the extracellular deposition of NOTCH3 ectodomain (Notch3(ECD) ) on the vessels. TIMP3 and vitronectin are two extracellular matrix proteins that abnormally accumulate in Notch3(ECD) -containing deposits on brain vessels of mice and patients with CADASIL. Herein, we investigated whether increased levels of TIMP3 and vitronectin are responsible for aspects of CADASIL disease phenotypes. Timp3 and vitronectin expression were genetically reduced in TgNotch3(R169C) mice, a well-established preclinical model of CADASIL. A mouse overexpressing human TIMP3 (TgBAC-TIMP3) was developed. Disease-related phenotypes, including cerebral blood flow deficits, white matter lesions and Notch3(ECD) deposition, were evaluated between 6 and 20 months of age. Cerebral blood flow responses to neural activity (functional hyperemia), topical application of vasodilators, and decreases in bl...

Amer J Physiol Heart Circ Phy, 2011

intact animal to the cellular, subcellular, and molecular levels. It is published 12 times a year... more intact animal to the cellular, subcellular, and molecular levels. It is published 12 times a year (monthly) by the American lymphatics, including experimental and theoretical studies of cardiovascular function at all levels of organization ranging from the publishes original investigations on the physiology of the heart, blood vessels, and AJP -Heart and Circulatory Physiology Hypertension alters cerebrovascular regulation and increases the brain's susceptibility to stroke and dementia. We investigated the temporal relationships between the arterial pressure (AP) elevation induced by "slow pressor" angiotensin II (ANG II) infusion, which recapitulates key features of human hypertension, and the resulting cerebrovascular dysfunction. Minipumps delivering saline or ANG II for 14 days were implanted subcutaneously in C57BL/6 mice (n ϭ 5/group). Cerebral blood flow was assessed by laser-Doppler flowmetry in anesthetized mice equipped with a cranial window. With ANG II (600 ng·kg Ϫ1 ·min Ϫ1 ), AP started to rise after 9 days (P Ͻ 0.05 vs. saline), remained elevated at 11-17 days, and returned to baseline at 21 days (P Ͼ 0.05). ANG II attenuated the cerebral blood flow increase induced by neural activity (whisker stimulation) or endotheliumdependent vasodilators, an effect observed before the AP elevation (7 days), as well as after the hypertension subsided (21 days). Nonpressor doses of ANG II (200 ng·kg Ϫ1 ·min Ϫ1 ) induced cerebrovascular dysfunction and oxidative stress without elevating AP (P Ͼ 0.05 vs. saline), whereas phenylephrine elevated AP without inducing cerebrovascular effects. ANG II (600 ng·kg Ϫ1 ·min Ϫ1 ) augmented neocortical reactive oxygen species (ROS) with a time course similar to that of the cerebrovascular dysfunction. Neocortical application of the ROS scavenger manganic(I-II)meso-tetrakis(4-benzoic acid)porphyrin or the NADPH oxidase peptide inhibitor gp91ds-tat attenuated ROS and cerebrovascular dysfunction. We conclude that the alterations in neurovascular regulation induced by slow pressor ANG II develop before hypertension and persist beyond AP normalization but are not permanent. The findings unveil a striking susceptibility of cerebrovascular function to the deleterious effects of ANG II and raise the possibility that cerebrovascular dysregulation precedes the elevation in AP also in patients with ANG II-dependent hypertension.

J Cerebr Blood Flow Metabol, 2005

Neuropsychopharmacology, 2007

Stroke a Journal of Cerebral Circulation, 2009

Aging, Alzheimer disease, and hypertension, major determinants of cognitive dysfunction, are asso... more Aging, Alzheimer disease, and hypertension, major determinants of cognitive dysfunction, are associated with profound alterations in the structure and function of cerebral blood vessels. These vascular alterations may impair the delivery of energy substrates and nutrients to the active brain, and impede the clearance of potentially toxic metabolic byproducts. Reactive oxygen species derived form the enzyme NADPH oxidase are key pathogenic effectors of the cerebrovascular dysregulation. The resulting alterations in the homeostasis of the cerebral microenvironment may lead to cellular dysfunction and death and to cognitive impairment. The prominent role that cerebrovascular oxidative stress plays in conditions associated with cognitive impairment suggests new therapeutic opportunities to counteract and, possibly, reverse the devastating effects of cerebrovascular dysfunction on the brain.

The Faseb Journal, Apr 1, 2009

Current Alzheimer Research, 2015

Hypertension, a risk factor for Alzheimer's disease (AD),... more Hypertension, a risk factor for Alzheimer's disease (AD), is a treatable condition, which offers possibilities for prevention of AD. Elevated angiotensin II (AngII) is an important cause of essential hypertension. AngII has deleterious effects on endothelial function and cerebral blood flow (CBF), which may contribute to AD. AngII blocking agents can thus provide potential candidates to reduce AD risk factors in hypertensive patients. We studied the effect of 2 months induced hypertension (AngII-infusion via osmotic micropumps) on systolic blood pressure (SBP) and CBF in 10 months-old wild-type (WT) C57bl/6j and AβPPswe/PS1ΔE9 (AβPP/PS1) mice, and treatment with two different antihypertensives, 1) eprosartan mesylate (EM, 0.35mg/kg) or 2) hydrochlorotiazide (HCT, 7.5mg/kg), after 1 month of induced-hypertension. SBP was monitored twice each month via tail cuff plethysmography. CBF was measured with MR by flow-sensitive alternating inversion recovery. Chronic AngII-infusion induced an increase in SBP in both AβPP/PS1 and WT mice accompanied by a decrease in hippocampal and thalamic CBF only in the AβPP/PS1 mice. An additional difference between the AβPP/PS1 mice and WT mice was that SBP was much higher in AβPP/PS1 mice in both hypertensive and normotensive conditions. Moreover, both antihypertensives were less effective in reducing AngII-induced hypertension to normal levels in AβPP/PS1 mice, while being effective in WT mice. It can be concluded that AngII-induced elevated SBP results in impaired CBF and a decreased response to blood pressure lowering treatment in a transgenic model of AD. Our findings suggest a relation between midlife hypertension and decreased CBF in an AD mouse model, similar to the relation which has been found in AD patients. This translational mouse model could be used to investigate possible prevention and treatment strategies for AD.

The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 4, 2012

Hypertension, a powerful risk factor for stroke and dementia, has damaging effects on the brain a... more Hypertension, a powerful risk factor for stroke and dementia, has damaging effects on the brain and its vessels. In particular, hypertension alters vital cerebrovascular control mechanisms linking neural activity to cerebral perfusion. In experimental models of slow-developing hypertension, free radical signaling in the subfornical organ (SFO), one of the forebrain circumventricular organs, is critical for the hormonal release and sympathetic activation driving the elevation in arterial pressure. However, the contribution of this central mechanism to the cerebrovascular alterations induced by hypertension remains uncertain. We tested the hypothesis that free radical production in the SFO is involved in the alterations in cerebrovascular regulation produced by hypertension. In a mouse model of gradual hypertension induced by chronic administration of subpressor doses of angiotensin II (AngII), suppression of free radicals in the SFO by overexpression of CuZn-superoxide dismutase (CuZ...

Proceedings of the National Academy of Sciences of the United States of America, Jan 29, 2008

Alterations in cerebrovascular regulation related to vascular oxidative stress have been implicat... more Alterations in cerebrovascular regulation related to vascular oxidative stress have been implicated in the mechanisms of Alzheimer's disease (AD), but their role in the amyloid deposition and cognitive impairment associated with AD remains unclear. We used mice overexpressing the Swedish mutation of the amyloid precursor protein (Tg2576) as a model of AD to examine the role of reactive oxygen species produced by NADPH oxidase in the cerebrovascular alterations, amyloid deposition, and behavioral deficits observed in these mice. We found that 12- to 15-month-old Tg2576 mice lacking the catalytic subunit Nox2 of NADPH oxidase do not develop oxidative stress, cerebrovascular dysfunction, or behavioral deficits. These improvements occurred without reductions in brain amyloid-beta peptide (Abeta) levels or amyloid plaques. The findings unveil a previously unrecognized role of Nox2-derived radicals in the behavioral deficits of Tg2576 mice and provide a link between the neurovascular ...

PLoS ONE, 2007

Background. Neurosphere-derived cells (NC), containing neural stem cells, various progenitors and... more Background. Neurosphere-derived cells (NC), containing neural stem cells, various progenitors and more differentiated cells, were obtained from newborn C57/BL6 mice and infused in a murine model of focal ischemia with reperfusion to investigate if: 1) they decreased ischemic injury and restored brain function; 2) they induced changes in the environment in which they are infused; 3) changes in brain environment consequent to transient ischemia were relevant for NC action. Methodology/ Principal Findings. NC were infused intracerebroventricularly 4 h or 7 d after 30 min middle cerebral artery occlusion. In ischemic mice receiving cells at 4 h, impairment of open field performance was significantly improved and neuronal loss significantly reduced 7-14 d after ischemia compared to controls and to ischemic mice receiving cells at 7 d. Infusion of murine foetal fibroblast in the same experimental conditions was not effective. Assessment of infused cell distribution revealed that they migrated from the ventricle to the parenchyma, progressively decreased in number but they were observable up to 14 d. In mice receiving NC at 7 d and in sham-operated mice, few cells could be observed only at 24 h, indicating that the survival of these cells in brain tissue relates to the ischemic environment. The mRNA expression of trophic factors such as Insulin Growth Factor-1, Vascular Endothelial Growth Factor-A, Transforming Growth Factor-b1, Brain Derived Neurotrophic Factor and Stromal Derived Factor21a, as well as microglia/macrophage activation, increased 24 h after NC infusion in ischemic mice treated at 4 h compared to sham-operated and to mice receiving cells at 7 d. Conclusions/Significance. NC reduce functional impairment and neuronal damage after ischemia/reperfusion injury. Several lines of evidence indicate that the reciprocal interaction between NC and the ischemic environment is crucial for NC protective actions. Based on these results we propose that a bystander control of the ischemic environment may be the mechanism used by NC to rapidly restore acutely injured brain function.

Journal of Neuroscience, 2013

PGRN deficiency on the brain in health and disease. PGRN has been implicated in neurovascular dev... more PGRN deficiency on the brain in health and disease. PGRN has been implicated in neurovascular development, inflammation, and Wnt signaling, a pathway involved in the formation of the blood-brain barrier (BBB). Because BBB alterations and inflammation contribute to ischemic brain injury, we examined the role of PGRN in the brain damage produced by ischemia-reperfusion. PGRN ϩ/Ϫ and PGRN Ϫ/Ϫ mice underwent middle cerebral artery occlusion (MCAO) with monitoring of cerebral blood flow. Infarct volume and motor deficits were assessed 72 h later. Post-ischemic inflammation was examined by expression of inflammatory genes and flow cytometry. BBB structure and permeability were examined by electron microscopy (EM) and Evans blue (EB) extravasation, respectively. MCAO resulted in ϳ60% larger infarcts in PGRN ϩ/Ϫ and PGRN Ϫ/Ϫ mice, an effect independent of hemodynamic factors or post-ischemic inflammation. Rather, massive hemorrhages and post-ischemic BBB disruption were observed, unrelated to degradation of tight junction (TJ) proteins or matrix metalloproteinases (MMPs). By EM, TJ were 30 -52% shorter, fewer, and less interlocking, suggesting a weaker seal between endothelial cells. Intracerebral injection of platelet-derived growth factor-CC (PDGF-CC), which increases BBB permeability, resulted in a more severe BBB breakdown in PGRN ϩ/Ϫ and PGRN Ϫ/Ϫ than wild-type mice. We describe a previously unrecognized involvement of PGRN in the expression of key ultrastructural features of the BBB. Such a novel vasoprotective role of PGRN may contribute to brain dysfunction and damage in conditions associated with reduced PGRN function.

Stroke, 2009

Aging, Alzheimer disease, and hypertension, major determinants of cognitive dysfunction, are asso... more Aging, Alzheimer disease, and hypertension, major determinants of cognitive dysfunction, are associated with profound alterations in the structure and function of cerebral blood vessels. These vascular alterations may impair the delivery of energy substrates and nutrients to the active brain, and impede the clearance of potentially toxic metabolic byproducts. Reactive oxygen species derived form the enzyme NADPH oxidase are key pathogenic effectors of the cerebrovascular dysregulation. The resulting alterations in the homeostasis of the cerebral microenvironment may lead to cellular dysfunction and death and to cognitive impairment. The prominent role that cerebrovascular oxidative stress plays in conditions associated with cognitive impairment suggests new therapeutic opportunities to counteract and, possibly, reverse the devastating effects of cerebrovascular dysfunction on the brain.

Neuropsychopharmacology, 2007

The effect of ST1942, a 2-aminotetraline derivative with anti-inflammatory properties, was evalua... more The effect of ST1942, a 2-aminotetraline derivative with anti-inflammatory properties, was evaluated in ischemia/reperfusion injury in CD1 and C57BL/6 mice. ST1942 or saline were injected intraperitoneally 30 min and 6, 24, 36 h after ischemia. Forty-eight hours after ischemia, ST1942 (25 mg/kg) reduced the infarct volume by 50% in CD1 and 61% in C57BL/6 mice. All subsequent data were obtained from the latter strain. The ischemic lesion was significantly reduced by 30% when the first injection was administered 6 h after ischemia, revealing a broad effective window. Degenerating neurons in striatum, cortex and hippocampus of ischemic mice were markedly decreased by ST1942. Also examined was the effect of ST1942 on general and focal neurological deficits for 4 days after ischemia. Mice receiving the drug twice daily showed constantly reduced deficits. We then investigated the cortical mRNA expression of some inflammatory and apoptotic genes by real-time PCR. Forty-eight hours after ischemia ST1942 treatment significantly counteracted ischemia-induced activation of IL-1b, TNFa, and Bax, and enhanced the expression of the antiapoptotic gene, Bcl-2, showing in vivo anti-inflammatory and antiapoptotic actions. The microglial activation/macrophage recruitment in the ischemic lesion was strongly prevented in mice receiving ST1942. In neuron-microglia cocultures, ST1942 significantly counteracted LPS-induced cytotoxicity. Binding data and experiments on microglial cell cultures indicate that the anti-inflammatory effect of ST1942 may be due to its action on 5-HT2B receptors, thus highlighting the possibility that this 5-HT receptor subtype may represent a novel target for neuroprotective drugs in ischemic injury.

Journal of Cerebral Blood Flow & Metabolism, 2013

Cyclooxygenase-2-derived prostaglandin E2 (PGE2) contributes to excitotoxic and ischemic neuronal... more Cyclooxygenase-2-derived prostaglandin E2 (PGE2) contributes to excitotoxic and ischemic neuronal cell death by engaging neuronal PGE2 type 1 receptors (EP1R). Our previous studies have shown that EP1R signaling resulted in disturbances of intracellular Ca(2+) homeostasis and suppression of the pro-survival protein kinase AKT. The aim of this study was to investigate whether these pathophysiological mechanism have a role in the neuronal cell death after transient forebrain ischemia. Mice were subjected to ischemia/reperfusion by bilateral common carotid artery occlusion. Hippocampal cornu ammonis area 1 (CA1) neuronal cell death was determined 5 days after reperfusion. Animals treated with the EP1R antagonist SC51089 or EP1R-deficient mice (EP1(-/-)) showed significantly less neuronal injury as compared to vehicle-treated wild-type controls. Benefits of EP1R blockage were still evident 14 days after injury. Better neuronal survival was correlated with reduced neuronal caspase-3 activity and decreased nuclear translocation of the apoptosis-inducing factor . Neuroprotection could be reverted by intracerebroventricular administration of the phosphoinositide 3-kinase inhibitor LY294002 and was not further increased by the calcineurin inhibitor FK506. These data implicate EP1R in postischemic neuronal apoptosis possibly by facilitating AKT inhibition.

Hypertension, 2010

Data Supplement (unedited) at: http://hyper.ahajournals.org located on the World Wide Web at:

Hypertension, 2009

Female mice are protected from the cerebrovascular dysfunction induced by angiotensin II (AngII),... more Female mice are protected from the cerebrovascular dysfunction induced by angiotensin II (AngII), an effect attributed to estrogen. We examined whether such cerebrovascular protection from AngII is related to the estrous cycle. Cerebral blood flow (CBF) was monitored by laser-Doppler flowmetry in anesthetized (urethane-chloralose) C57BL/6 female mice equipped with a cranial window. The phase of the estrous cycle was determined by vaginal smear cytology and plasma estrogen measurement. AngII (0.25 μg/Kg/min; i.v.; 30-45 min) elevated arterial pressure (15-20 mmHg) equally across the estrous cycle. However, in proestrus and estrus, phases in which estrogen is relatively high, AngII did not impair the in increase in the CBF induced by neural activity or by endothelium-dependent vasodilators (p>0.05 from vehicle). In contrast, in diestrus (lower estrogen) AngII induced a marked cerebrovascular dysfunction comparable to that of males. For example, the CBF response to whisker stimulation and to the endothelium-dependent vasodilator acetylcholine were attenuated by 41±12% and 49±12%, respectively (p<0.05; n=6/group). The protection from the cerebrovascular effects of AngII in proestrus was abolished by the estrogen receptor inhibitor ICI182,780. AngII also increased production of free radicals in cerebral blood vessels in diestrus (+116±13%; p<0.05), but not in proestrus and estrus (p>0.05 from control). Topical treatment with ICI182,780 reestablished AngII-induced oxidative stress in proestrus (p>0.05 from diestrus). We conclude that the protection from the neurovascular dysfunction induced by acute administration of AngII in females depends on the estrous cycle and may underlie the increased propensity to cerebrovascular damage associated with low estrogen states.

Journal of Cerebral Blood Flow & Metabolism, 2005

Cerebral small vessel disease (SVD) is a leading cause of stroke and dementia.

Annals of neurology, Jan 9, 2015

CADASIL is a genetic paradigm of cerebral small vessel disease caused by NOTCH3 mutations that st... more CADASIL is a genetic paradigm of cerebral small vessel disease caused by NOTCH3 mutations that stereotypically lead to the extracellular deposition of NOTCH3 ectodomain (Notch3(ECD) ) on the vessels. TIMP3 and vitronectin are two extracellular matrix proteins that abnormally accumulate in Notch3(ECD) -containing deposits on brain vessels of mice and patients with CADASIL. Herein, we investigated whether increased levels of TIMP3 and vitronectin are responsible for aspects of CADASIL disease phenotypes. Timp3 and vitronectin expression were genetically reduced in TgNotch3(R169C) mice, a well-established preclinical model of CADASIL. A mouse overexpressing human TIMP3 (TgBAC-TIMP3) was developed. Disease-related phenotypes, including cerebral blood flow deficits, white matter lesions and Notch3(ECD) deposition, were evaluated between 6 and 20 months of age. Cerebral blood flow responses to neural activity (functional hyperemia), topical application of vasodilators, and decreases in bl...

Amer J Physiol Heart Circ Phy, 2011

intact animal to the cellular, subcellular, and molecular levels. It is published 12 times a year... more intact animal to the cellular, subcellular, and molecular levels. It is published 12 times a year (monthly) by the American lymphatics, including experimental and theoretical studies of cardiovascular function at all levels of organization ranging from the publishes original investigations on the physiology of the heart, blood vessels, and AJP -Heart and Circulatory Physiology Hypertension alters cerebrovascular regulation and increases the brain's susceptibility to stroke and dementia. We investigated the temporal relationships between the arterial pressure (AP) elevation induced by "slow pressor" angiotensin II (ANG II) infusion, which recapitulates key features of human hypertension, and the resulting cerebrovascular dysfunction. Minipumps delivering saline or ANG II for 14 days were implanted subcutaneously in C57BL/6 mice (n ϭ 5/group). Cerebral blood flow was assessed by laser-Doppler flowmetry in anesthetized mice equipped with a cranial window. With ANG II (600 ng·kg Ϫ1 ·min Ϫ1 ), AP started to rise after 9 days (P Ͻ 0.05 vs. saline), remained elevated at 11-17 days, and returned to baseline at 21 days (P Ͼ 0.05). ANG II attenuated the cerebral blood flow increase induced by neural activity (whisker stimulation) or endotheliumdependent vasodilators, an effect observed before the AP elevation (7 days), as well as after the hypertension subsided (21 days). Nonpressor doses of ANG II (200 ng·kg Ϫ1 ·min Ϫ1 ) induced cerebrovascular dysfunction and oxidative stress without elevating AP (P Ͼ 0.05 vs. saline), whereas phenylephrine elevated AP without inducing cerebrovascular effects. ANG II (600 ng·kg Ϫ1 ·min Ϫ1 ) augmented neocortical reactive oxygen species (ROS) with a time course similar to that of the cerebrovascular dysfunction. Neocortical application of the ROS scavenger manganic(I-II)meso-tetrakis(4-benzoic acid)porphyrin or the NADPH oxidase peptide inhibitor gp91ds-tat attenuated ROS and cerebrovascular dysfunction. We conclude that the alterations in neurovascular regulation induced by slow pressor ANG II develop before hypertension and persist beyond AP normalization but are not permanent. The findings unveil a striking susceptibility of cerebrovascular function to the deleterious effects of ANG II and raise the possibility that cerebrovascular dysregulation precedes the elevation in AP also in patients with ANG II-dependent hypertension.

J Cerebr Blood Flow Metabol, 2005

Neuropsychopharmacology, 2007

Stroke a Journal of Cerebral Circulation, 2009

Aging, Alzheimer disease, and hypertension, major determinants of cognitive dysfunction, are asso... more Aging, Alzheimer disease, and hypertension, major determinants of cognitive dysfunction, are associated with profound alterations in the structure and function of cerebral blood vessels. These vascular alterations may impair the delivery of energy substrates and nutrients to the active brain, and impede the clearance of potentially toxic metabolic byproducts. Reactive oxygen species derived form the enzyme NADPH oxidase are key pathogenic effectors of the cerebrovascular dysregulation. The resulting alterations in the homeostasis of the cerebral microenvironment may lead to cellular dysfunction and death and to cognitive impairment. The prominent role that cerebrovascular oxidative stress plays in conditions associated with cognitive impairment suggests new therapeutic opportunities to counteract and, possibly, reverse the devastating effects of cerebrovascular dysfunction on the brain.

The Faseb Journal, Apr 1, 2009

Current Alzheimer Research, 2015

Hypertension, a risk factor for Alzheimer&amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease (AD),... more Hypertension, a risk factor for Alzheimer&amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease (AD), is a treatable condition, which offers possibilities for prevention of AD. Elevated angiotensin II (AngII) is an important cause of essential hypertension. AngII has deleterious effects on endothelial function and cerebral blood flow (CBF), which may contribute to AD. AngII blocking agents can thus provide potential candidates to reduce AD risk factors in hypertensive patients. We studied the effect of 2 months induced hypertension (AngII-infusion via osmotic micropumps) on systolic blood pressure (SBP) and CBF in 10 months-old wild-type (WT) C57bl/6j and AβPPswe/PS1ΔE9 (AβPP/PS1) mice, and treatment with two different antihypertensives, 1) eprosartan mesylate (EM, 0.35mg/kg) or 2) hydrochlorotiazide (HCT, 7.5mg/kg), after 1 month of induced-hypertension. SBP was monitored twice each month via tail cuff plethysmography. CBF was measured with MR by flow-sensitive alternating inversion recovery. Chronic AngII-infusion induced an increase in SBP in both AβPP/PS1 and WT mice accompanied by a decrease in hippocampal and thalamic CBF only in the AβPP/PS1 mice. An additional difference between the AβPP/PS1 mice and WT mice was that SBP was much higher in AβPP/PS1 mice in both hypertensive and normotensive conditions. Moreover, both antihypertensives were less effective in reducing AngII-induced hypertension to normal levels in AβPP/PS1 mice, while being effective in WT mice. It can be concluded that AngII-induced elevated SBP results in impaired CBF and a decreased response to blood pressure lowering treatment in a transgenic model of AD. Our findings suggest a relation between midlife hypertension and decreased CBF in an AD mouse model, similar to the relation which has been found in AD patients. This translational mouse model could be used to investigate possible prevention and treatment strategies for AD.

The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 4, 2012

Hypertension, a powerful risk factor for stroke and dementia, has damaging effects on the brain a... more Hypertension, a powerful risk factor for stroke and dementia, has damaging effects on the brain and its vessels. In particular, hypertension alters vital cerebrovascular control mechanisms linking neural activity to cerebral perfusion. In experimental models of slow-developing hypertension, free radical signaling in the subfornical organ (SFO), one of the forebrain circumventricular organs, is critical for the hormonal release and sympathetic activation driving the elevation in arterial pressure. However, the contribution of this central mechanism to the cerebrovascular alterations induced by hypertension remains uncertain. We tested the hypothesis that free radical production in the SFO is involved in the alterations in cerebrovascular regulation produced by hypertension. In a mouse model of gradual hypertension induced by chronic administration of subpressor doses of angiotensin II (AngII), suppression of free radicals in the SFO by overexpression of CuZn-superoxide dismutase (CuZ...

Proceedings of the National Academy of Sciences of the United States of America, Jan 29, 2008

Alterations in cerebrovascular regulation related to vascular oxidative stress have been implicat... more Alterations in cerebrovascular regulation related to vascular oxidative stress have been implicated in the mechanisms of Alzheimer's disease (AD), but their role in the amyloid deposition and cognitive impairment associated with AD remains unclear. We used mice overexpressing the Swedish mutation of the amyloid precursor protein (Tg2576) as a model of AD to examine the role of reactive oxygen species produced by NADPH oxidase in the cerebrovascular alterations, amyloid deposition, and behavioral deficits observed in these mice. We found that 12- to 15-month-old Tg2576 mice lacking the catalytic subunit Nox2 of NADPH oxidase do not develop oxidative stress, cerebrovascular dysfunction, or behavioral deficits. These improvements occurred without reductions in brain amyloid-beta peptide (Abeta) levels or amyloid plaques. The findings unveil a previously unrecognized role of Nox2-derived radicals in the behavioral deficits of Tg2576 mice and provide a link between the neurovascular ...

PLoS ONE, 2007

Background. Neurosphere-derived cells (NC), containing neural stem cells, various progenitors and... more Background. Neurosphere-derived cells (NC), containing neural stem cells, various progenitors and more differentiated cells, were obtained from newborn C57/BL6 mice and infused in a murine model of focal ischemia with reperfusion to investigate if: 1) they decreased ischemic injury and restored brain function; 2) they induced changes in the environment in which they are infused; 3) changes in brain environment consequent to transient ischemia were relevant for NC action. Methodology/ Principal Findings. NC were infused intracerebroventricularly 4 h or 7 d after 30 min middle cerebral artery occlusion. In ischemic mice receiving cells at 4 h, impairment of open field performance was significantly improved and neuronal loss significantly reduced 7-14 d after ischemia compared to controls and to ischemic mice receiving cells at 7 d. Infusion of murine foetal fibroblast in the same experimental conditions was not effective. Assessment of infused cell distribution revealed that they migrated from the ventricle to the parenchyma, progressively decreased in number but they were observable up to 14 d. In mice receiving NC at 7 d and in sham-operated mice, few cells could be observed only at 24 h, indicating that the survival of these cells in brain tissue relates to the ischemic environment. The mRNA expression of trophic factors such as Insulin Growth Factor-1, Vascular Endothelial Growth Factor-A, Transforming Growth Factor-b1, Brain Derived Neurotrophic Factor and Stromal Derived Factor21a, as well as microglia/macrophage activation, increased 24 h after NC infusion in ischemic mice treated at 4 h compared to sham-operated and to mice receiving cells at 7 d. Conclusions/Significance. NC reduce functional impairment and neuronal damage after ischemia/reperfusion injury. Several lines of evidence indicate that the reciprocal interaction between NC and the ischemic environment is crucial for NC protective actions. Based on these results we propose that a bystander control of the ischemic environment may be the mechanism used by NC to rapidly restore acutely injured brain function.

Journal of Neuroscience, 2013

PGRN deficiency on the brain in health and disease. PGRN has been implicated in neurovascular dev... more PGRN deficiency on the brain in health and disease. PGRN has been implicated in neurovascular development, inflammation, and Wnt signaling, a pathway involved in the formation of the blood-brain barrier (BBB). Because BBB alterations and inflammation contribute to ischemic brain injury, we examined the role of PGRN in the brain damage produced by ischemia-reperfusion. PGRN ϩ/Ϫ and PGRN Ϫ/Ϫ mice underwent middle cerebral artery occlusion (MCAO) with monitoring of cerebral blood flow. Infarct volume and motor deficits were assessed 72 h later. Post-ischemic inflammation was examined by expression of inflammatory genes and flow cytometry. BBB structure and permeability were examined by electron microscopy (EM) and Evans blue (EB) extravasation, respectively. MCAO resulted in ϳ60% larger infarcts in PGRN ϩ/Ϫ and PGRN Ϫ/Ϫ mice, an effect independent of hemodynamic factors or post-ischemic inflammation. Rather, massive hemorrhages and post-ischemic BBB disruption were observed, unrelated to degradation of tight junction (TJ) proteins or matrix metalloproteinases (MMPs). By EM, TJ were 30 -52% shorter, fewer, and less interlocking, suggesting a weaker seal between endothelial cells. Intracerebral injection of platelet-derived growth factor-CC (PDGF-CC), which increases BBB permeability, resulted in a more severe BBB breakdown in PGRN ϩ/Ϫ and PGRN Ϫ/Ϫ than wild-type mice. We describe a previously unrecognized involvement of PGRN in the expression of key ultrastructural features of the BBB. Such a novel vasoprotective role of PGRN may contribute to brain dysfunction and damage in conditions associated with reduced PGRN function.

Stroke, 2009

Aging, Alzheimer disease, and hypertension, major determinants of cognitive dysfunction, are asso... more Aging, Alzheimer disease, and hypertension, major determinants of cognitive dysfunction, are associated with profound alterations in the structure and function of cerebral blood vessels. These vascular alterations may impair the delivery of energy substrates and nutrients to the active brain, and impede the clearance of potentially toxic metabolic byproducts. Reactive oxygen species derived form the enzyme NADPH oxidase are key pathogenic effectors of the cerebrovascular dysregulation. The resulting alterations in the homeostasis of the cerebral microenvironment may lead to cellular dysfunction and death and to cognitive impairment. The prominent role that cerebrovascular oxidative stress plays in conditions associated with cognitive impairment suggests new therapeutic opportunities to counteract and, possibly, reverse the devastating effects of cerebrovascular dysfunction on the brain.

Neuropsychopharmacology, 2007

The effect of ST1942, a 2-aminotetraline derivative with anti-inflammatory properties, was evalua... more The effect of ST1942, a 2-aminotetraline derivative with anti-inflammatory properties, was evaluated in ischemia/reperfusion injury in CD1 and C57BL/6 mice. ST1942 or saline were injected intraperitoneally 30 min and 6, 24, 36 h after ischemia. Forty-eight hours after ischemia, ST1942 (25 mg/kg) reduced the infarct volume by 50% in CD1 and 61% in C57BL/6 mice. All subsequent data were obtained from the latter strain. The ischemic lesion was significantly reduced by 30% when the first injection was administered 6 h after ischemia, revealing a broad effective window. Degenerating neurons in striatum, cortex and hippocampus of ischemic mice were markedly decreased by ST1942. Also examined was the effect of ST1942 on general and focal neurological deficits for 4 days after ischemia. Mice receiving the drug twice daily showed constantly reduced deficits. We then investigated the cortical mRNA expression of some inflammatory and apoptotic genes by real-time PCR. Forty-eight hours after ischemia ST1942 treatment significantly counteracted ischemia-induced activation of IL-1b, TNFa, and Bax, and enhanced the expression of the antiapoptotic gene, Bcl-2, showing in vivo anti-inflammatory and antiapoptotic actions. The microglial activation/macrophage recruitment in the ischemic lesion was strongly prevented in mice receiving ST1942. In neuron-microglia cocultures, ST1942 significantly counteracted LPS-induced cytotoxicity. Binding data and experiments on microglial cell cultures indicate that the anti-inflammatory effect of ST1942 may be due to its action on 5-HT2B receptors, thus highlighting the possibility that this 5-HT receptor subtype may represent a novel target for neuroprotective drugs in ischemic injury.

Journal of Cerebral Blood Flow & Metabolism, 2013

Cyclooxygenase-2-derived prostaglandin E2 (PGE2) contributes to excitotoxic and ischemic neuronal... more Cyclooxygenase-2-derived prostaglandin E2 (PGE2) contributes to excitotoxic and ischemic neuronal cell death by engaging neuronal PGE2 type 1 receptors (EP1R). Our previous studies have shown that EP1R signaling resulted in disturbances of intracellular Ca(2+) homeostasis and suppression of the pro-survival protein kinase AKT. The aim of this study was to investigate whether these pathophysiological mechanism have a role in the neuronal cell death after transient forebrain ischemia. Mice were subjected to ischemia/reperfusion by bilateral common carotid artery occlusion. Hippocampal cornu ammonis area 1 (CA1) neuronal cell death was determined 5 days after reperfusion. Animals treated with the EP1R antagonist SC51089 or EP1R-deficient mice (EP1(-/-)) showed significantly less neuronal injury as compared to vehicle-treated wild-type controls. Benefits of EP1R blockage were still evident 14 days after injury. Better neuronal survival was correlated with reduced neuronal caspase-3 activity and decreased nuclear translocation of the apoptosis-inducing factor . Neuroprotection could be reverted by intracerebroventricular administration of the phosphoinositide 3-kinase inhibitor LY294002 and was not further increased by the calcineurin inhibitor FK506. These data implicate EP1R in postischemic neuronal apoptosis possibly by facilitating AKT inhibition.

Hypertension, 2010

Data Supplement (unedited) at: http://hyper.ahajournals.org located on the World Wide Web at:

Hypertension, 2009

Female mice are protected from the cerebrovascular dysfunction induced by angiotensin II (AngII),... more Female mice are protected from the cerebrovascular dysfunction induced by angiotensin II (AngII), an effect attributed to estrogen. We examined whether such cerebrovascular protection from AngII is related to the estrous cycle. Cerebral blood flow (CBF) was monitored by laser-Doppler flowmetry in anesthetized (urethane-chloralose) C57BL/6 female mice equipped with a cranial window. The phase of the estrous cycle was determined by vaginal smear cytology and plasma estrogen measurement. AngII (0.25 μg/Kg/min; i.v.; 30-45 min) elevated arterial pressure (15-20 mmHg) equally across the estrous cycle. However, in proestrus and estrus, phases in which estrogen is relatively high, AngII did not impair the in increase in the CBF induced by neural activity or by endothelium-dependent vasodilators (p>0.05 from vehicle). In contrast, in diestrus (lower estrogen) AngII induced a marked cerebrovascular dysfunction comparable to that of males. For example, the CBF response to whisker stimulation and to the endothelium-dependent vasodilator acetylcholine were attenuated by 41±12% and 49±12%, respectively (p<0.05; n=6/group). The protection from the cerebrovascular effects of AngII in proestrus was abolished by the estrogen receptor inhibitor ICI182,780. AngII also increased production of free radicals in cerebral blood vessels in diestrus (+116±13%; p<0.05), but not in proestrus and estrus (p>0.05 from control). Topical treatment with ICI182,780 reestablished AngII-induced oxidative stress in proestrus (p>0.05 from diestrus). We conclude that the protection from the neurovascular dysfunction induced by acute administration of AngII in females depends on the estrous cycle and may underlie the increased propensity to cerebrovascular damage associated with low estrogen states.

Journal of Cerebral Blood Flow & Metabolism, 2005