scholarly journals Chronic cerebral hypoperfusion alters amyloid-β peptide pools leading to cerebral amyloid angiopathy, microinfarcts and haemorrhages in Tg-SwDI mice

2017 ◽  
Vol 131 (16) ◽  
pp. 2109-2123 ◽  
Author(s):  
Natalia Salvadores ◽  
James L. Searcy ◽  
Philip R. Holland ◽  
Karen Horsburgh
Keyword(s):  
Amyloid Β ◽  
Chronic Cerebral Hypoperfusion ◽  
Cerebral Hypoperfusion ◽  
Amyloid Angiopathy ◽  
Amyloid Β Peptide ◽  
Wild Type ◽  
Aβ Peptides ◽  
Bilateral Carotid ◽  
The Brain ◽  
Bilateral Carotid Artery

Cerebral hypoperfusion is an early feature of Alzheimer’s disease (AD) that influences the progression from mild cognitive impairment to dementia. Understanding the mechanism is of critical importance in the search for new effective therapies. We hypothesized that cerebral hypoperfusion promotes the accumulation of amyloid-β (Aβ) and degenerative changes in the brain and is a potential mechanism contributing to development of dementia. To address this, we studied the effects of chronic cerebral hypoperfusion induced by bilateral carotid artery stenosis on Aβ peptide pools in a transgenic mouse model of AD (transgenic mice with Swedish, Dutch and Iowa mutations in human amyloid precursor protein (APP) (Tg-SwDI)). Cerebrovascular integrity was characterized by quantifying the occurrence of microinfarcts and haemorrhages and compared with wild-type mice without Aβ. A significant increase in soluble Aβ peptides (Aβ40/42) was detected after 1 month of hypoperfusion in the parenchyma in parallel with elevated APP and APP proteolytic products. Following 3 months, a significant increase in insoluble Aβ40/42 was determined in the parenchyma and vasculature. Microinfarct load was significantly increased in the Tg-SwDI as compared with wild-type mice and further exacerbated by hypoperfusion at 1 and 3 months. In addition, the number of Tg-SwDI hypoperfused mice with haemorrhages was increased compared with hypoperfused wild-type mice. Soluble parenchymal Aβ was associated with elevated NADPH oxidase-2 (NOX2) which was exacerbated by 1-month hypoperfusion. We suggest that in response to hypoperfusion, increased Aβ production/deposition may contribute to degenerative processes by triggering oxidative stress promoting cerebrovascular disruption and the development of microinfarcts.

Chronic cerebral hypoperfusion in male rats results in sustained HPA activation, and hyperinsulinemia

2021 ◽  
Author(s):  
Theresa A. Lansdell ◽  
Anne M Dorrance
Keyword(s):  
Insulin Resistance ◽  
Chronic Cerebral Hypoperfusion ◽  
Cerebral Hypoperfusion ◽  
Male Rats ◽  
Lower Blood Glucose ◽  
Insulin Resistant ◽  
Lower Blood ◽  
Bilateral Carotid ◽  
Glucose Tolerance Tests ◽  
Bilateral Carotid Artery

Vascular contributions to cognitive impairment and dementia (VCID) is a spectrum of cognitive deficits caused by cerebrovascular disease, for which insulin resistance is a major risk factor. A major cause of VCID is chronic cerebral hypoperfusion (CCH). Under stress, sustained hypothalamic-pituitary-adrenal axis (HPA) activation can result in insulin resistance. Little is known about the effects of CCH on the HPA axis. We hypothesized that CCH causes sustained HPA activation and insulin resistance. Male rats were subjected to bilateral carotid artery stenosis (BCAS) for 12 weeks to induce CCH and VCID. BCAS reduced cerebral blood flow and caused memory impairment. Plasma adrenocorticotropic hormone was increased in the BCAS rats (117.2 ± 9.6 vs. 88.29 ± 9.1 pg/mL, BCAS vs. sham, p = 0.0236), as was corticosterone (220 ± 21 vs. 146 ± 18 ng/g feces, BCAS vs. sham, p = 0.0083). BCAS rats were hypoglycemic (68.1 ± 6.1 vs. 76.5± 5.9 mg/dL, BCAS vs. sham, p = 0.0072), with increased fasting insulin (481.6 ± 242.6 vs. 97.94± 40.02 pmol/L, BCAS vs. sham, p = 0.0003) indicating BCAS rats were insulin resistant (HOMA-IR:11.71 ± 6.47 vs. 2.62 ± 0.93; BCAS vs. control, p = 0.0008). Glucose tolerance tests revealed that BCAS rats had lower blood glucose AUCs than controls (250 ± 12 vs. 326 ± 20 mg/dL/h, BCAS vs. sham, p = 0.0075). These studies indicate that CCH causes sustained activation of the HPA and results in insulin resistance, a condition that is expected to worsen VCID.

Altered expression of neurofilament 200 and amyloid-β peptide (1–40) in a rat model of chronic cerebral hypoperfusion

2014 ◽  
Vol 36 (5) ◽  
pp. 707-712 ◽  
Author(s):  
Weihua Liang ◽  
Weiwei Zhang ◽  
Shifu Zhao ◽  
Qianning Li ◽  
Hua Liang ◽  
...  
Keyword(s):  
Rat Model ◽  
Amyloid Β ◽  
Chronic Cerebral Hypoperfusion ◽  
Cerebral Hypoperfusion ◽  
Amyloid Β Peptide ◽  
Altered Expression ◽  
Neurofilament 200

scholarly journals Angiotensin IV suppresses inflammation in the brains of rats with chronic cerebral hypoperfusion

2018 ◽  
Vol 19 (3) ◽  
pp. 147032031879958 ◽  
Author(s):  
Qing-Guang Wang ◽  
Xiao Xue ◽  
Yang Yang ◽  
Peng-Yu Gong ◽  
Teng Jiang ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Neurological Diseases ◽  
Amyloid Β ◽  
Chronic Cerebral Hypoperfusion ◽  
Cerebral Hypoperfusion ◽  
Angiotensin Iv ◽  
Artificial Cerebrospinal Fluid ◽  
Ang Iv ◽  
The Brain ◽  
Pro Inflammatory Cytokines

Introduction: This study aimed to evaluate the influence of central angiotensin IV (Ang IV) infusion on chronic cerebral hypoperfusion (CCH)-related neuropathological changes including amyloid-β (Aβ), hyperphosphorylated tau (p-tau) and the inflammatory response. Materials and methods: Rats with CCH received central infusion of Ang IV, its receptor AT4R antagonist divalinal-Ang IV or artificial cerebrospinal fluid for six weeks. During this procedure, the systolic blood pressure (SBP) was monitored, and the levels of Aβ42, p-tau and pro-inflammatory cytokines in the brain were detected. Results: Rats with CCH exhibited higher levels of Aβ42, p-tau and pro-inflammatory cytokines in the brain when compared with controls. Infusion of Ang IV significantly reduced the expression of pro-inflammatory cytokines in the brains of rats with CCH. Meanwhile, the reduction of pro-inflammatory cytokines levels caused by Ang IV was reversed by divalinal-Ang IV. During the treatment, the SBP in rats was not significantly altered. Conclusion: This study demonstrates for the first time that Ang IV dose-dependently suppresses inflammation through AT4R in the brains of rats with CCH, which is independent from SBP. These findings suggest that Ang IV/AT4R may represent a potential therapeutic target for CCH-related neurological diseases.

scholarly journals The Neurovascular Unit Dysfunction in Alzheimer’s Disease

2021 ◽  
Vol 22 (4) ◽  
pp. 2022 ◽  
Author(s):  
Luis O. Soto-Rojas ◽  
Mar Pacheco-Herrero ◽  
Paola A. Martínez-Gómez ◽  
B. Berenice Campa-Córdoba ◽  
Ricardo Apátiga-Pérez ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurovascular Unit ◽  
Amyloid Β ◽  
Brain Parenchyma ◽  
Amyloid Angiopathy ◽  
Amyloid Β Peptide ◽  
Vascular Risk ◽  
Therapeutic Approaches ◽  
The Brain

Alzheimer’s disease (AD) is the most common neurodegenerative disease worldwide. Histopathologically, AD presents with two hallmarks: neurofibrillary tangles (NFTs), and aggregates of amyloid β peptide (Aβ) both in the brain parenchyma as neuritic plaques, and around blood vessels as cerebral amyloid angiopathy (CAA). According to the vascular hypothesis of AD, vascular risk factors can result in dysregulation of the neurovascular unit (NVU) and hypoxia. Hypoxia may reduce Aβ clearance from the brain and increase its production, leading to both parenchymal and vascular accumulation of Aβ. An increase in Aβ amplifies neuronal dysfunction, NFT formation, and accelerates neurodegeneration, resulting in dementia. In recent decades, therapeutic approaches have attempted to decrease the levels of abnormal Aβ or tau levels in the AD brain. However, several of these approaches have either been associated with an inappropriate immune response triggering inflammation, or have failed to improve cognition. Here, we review the pathogenesis and potential therapeutic targets associated with dysfunction of the NVU in AD.

scholarly journals Advances in our Understanding of the Pathophysiology, Detection and Management of Cerebral Amyloid Angiopathy

2012 ◽  
Vol 7 (2) ◽  
pp. 134 ◽  
Author(s):  
Octavio M Pontes-Neto ◽  
Eitan Auriel ◽  
Steven M Greenberg ◽  
◽  
◽  
...  
Keyword(s):  
Cerebral Amyloid Angiopathy ◽  
Small Vessel Disease ◽  
Specific Treatment ◽  
Amyloid Β ◽  
Amyloid Angiopathy ◽  
Amyloid Β Peptide ◽  
Small Vessels ◽  
The Media ◽  
Cerebral Amyloid ◽  
The Brain

Cerebral amyloid angiopathy (CAA) is pathologically defined as the deposition of amyloid protein, most commonly the amyloid β peptide (Aβ), primarily within the media and adventitia of small and medium-sized arteries of the leptomeninges, cerebral and cerebellar cortex. This deposition likely reflects an imbalance between Aβ production and clearance within the brain and leads to weakening of the overall structure of brain small vessels, predisposing patients tolobar intracerebral haemorrhage (ICH), brain ischaemia and cognitive decline. CAA is associated with markers of small vessel disease, like lobar microbleeds and white matter hyperintensities on magnetic resonance imaging. Therefore, it can be now be diagnosed during life with reasonable accuracy by clinical and neuroimaging criteria. Despite the lack of a specific treatment for this condition, the detection of CAA may help in the management of patients, regarding the prevention of major haemorrhagic complications and genetic counselling. This review discusses recent advances in our understanding of the pathophysiology, detection and management of CAA.

scholarly journals Effects of Amyloid Beta Peptide on Neurovascular Cells

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
Sholpan Askarova ◽  
Andrey Tsoy ◽  
Tamara Shalakhmetova ◽  
James C-M Lee
Keyword(s):  
Molecular Mechanisms ◽  
Neurodegenerative Disorder ◽  
Early Stage ◽  
Treatment Strategies ◽  
Amyloid Β ◽  
Amyloid Angiopathy ◽  
Amyloid Β Peptide ◽  
Inflammatory Reactions ◽  
Inflammatory Processes ◽  
The Brain

Alzheimer’s disease (AD) is a chronic neurodegenerative disorder, which is characterized by the accumulation of amyloid plaques and neurofibrillary tangles in specific regions of the brain, accompanied by impairment of the neurons, and progressive deterioration of cognition and memory of affected individuals. Although the cause and progression of AD are still not well understood, the amyloid hypothesis is dominant and widely accepted. According to this hypothesis, an increased deposition of amyloid-β peptide (Aβ) in the brain is the main cause of the AD’s onset and progression. There is increasing body of evidence that blood-brain barrier (BBB) dysfunction plays an important role in the development of AD, and may even precede neuron degeneration in AD brain. In the early stage of AD, microvasculature deficiencies, inflammatory reactions, surrounding the cerebral vasculature and endothelial dysfunctions are commonly observed. Continuous neurovascular degeneration and accumulation of Aβ on blood vessels resulting in cerebral amyloid angiopathy is associated with further progression of the disease and cognitive decline. However, little is known about molecular mechanisms that underlie Aβ induced damage of neurovascular cells. In this regards, this review is aimed to address how Aβ impacts the cerebral endothelium.  Understanding the cellular pathways triggered by Aβ leading to alterations in cerebral endothelial cells structure and functions would provide insights into the mechanism of BBB dysfunction and inflammatory processes in Alzheimer’s, and may offer new approaches for prevention and treatment strategies for AD. 

scholarly journals Chronic cerebral hypoperfusion accelerates amyloid β deposition in APPSwInd transgenic mice

2009 ◽  
Vol 1294 ◽  
pp. 202-210 ◽  
Author(s):  
Hiroshi Kitaguchi ◽  
Hidekazu Tomimoto ◽  
Masafumi Ihara ◽  
Masunari Shibata ◽  
Kengo Uemura ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Amyloid Β ◽  
Chronic Cerebral Hypoperfusion ◽  
Cerebral Hypoperfusion
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