scholarly journals Fibrin deposition accelerates neurovascular damage and neuroinflammation in mouse models of Alzheimer's disease

2007 ◽  
Vol 204 (8) ◽  
pp. 1999-2008 ◽  
Author(s):  
Justin Paul ◽  
Sidney Strickland ◽  
Jerry P. Melchor
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Blood Brain Barrier ◽  
Mouse Models ◽  
Brain Barrier ◽  
Vascular Pathology ◽  
Fibrin Deposition ◽  
Blood Brain ◽  
Neurovascular Damage ◽  
Blood Brain Barrier Damage

Cerebrovascular dysfunction contributes to the pathology and progression of Alzheimer's disease (AD), but the mechanisms are not completely understood. Using transgenic mouse models of AD (TgCRND8, PDAPP, and Tg2576), we evaluated blood–brain barrier damage and the role of fibrin and fibrinolysis in the progression of amyloid-β pathology. These mouse models showed age-dependent fibrin deposition coincident with areas of blood–brain barrier permeability as demonstrated by Evans blue extravasation. Three lines of evidence suggest that fibrin contributes to the pathology. First, AD mice with only one functional plasminogen gene, and therefore with reduced fibrinolysis, have increased neurovascular damage relative to AD mice. Conversely, AD mice with only one functional fibrinogen gene have decreased blood–brain barrier damage. Second, treatment of AD mice with the plasmin inhibitor tranexamic acid aggravated pathology, whereas removal of fibrinogen from the circulation of AD mice with ancrod treatment attenuated measures of neuroinflammation and vascular pathology. Third, pretreatment with ancrod reduced the increased pathology from plasmin inhibition. These results suggest that fibrin is a mediator of inflammation and may impede the reparative process for neurovascular damage in AD. Fibrin and the mechanisms involved in its accumulation and clearance may present novel therapeutic targets in slowing the progression of AD.

scholarly journals A Leaky Blood–Brain Barrier to Fibrinogen Contributes to Oxidative Damage in Alzheimer’s Disease

Antioxidants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 102
Author(s):  
James G. McLarnon
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Blood Brain Barrier ◽  
Immune Cell ◽  
Neurovascular Unit ◽  
Amyloid Β ◽  
Brain Barrier ◽  
Vascular Pathology ◽  
Immune Reactivity ◽  
Blood Brain

The intactness of blood–brain barrier (BBB) is compromised in Alzheimer’s disease (AD). Importantly, evidence suggests that the perturbation and abnormalities appearing in BBB can manifest early in the progression of the disease. The disruption of BBB allows extravasation of the plasma protein, fibrinogen, to enter brain parenchyma, eliciting immune reactivity and response. The presence of amyloid-β (Aβ) peptide leads to the formation of abnormal aggregates of fibrin resistant to degradation. Furthermore, Aβ deposits act on the contact system of blood coagulation, altering levels of thrombin, fibrin clots and neuroinflammation. The neurovascular unit (NVU) comprises an ensemble of brain cells which interact with infiltrating fibrinogen. In particular, interaction of resident immune cell microglia with fibrinogen, fibrin and Aβ results in the production of reactive oxygen species (ROS), a neurotoxic effector in AD brain. Overall, fibrinogen infiltration through a leaky BBB in AD animal models and in human AD tissue is associated with manifold abnormalities including persistent fibrin aggregation and clots, microglial-mediated production of ROS and diminished viability of neurons and synaptic connectivity. An objective of this review is to better understand how processes associated with BBB leakiness to fibrinogen link vascular pathology with neuronal and synaptic damage in AD.

scholarly journals A first-principles study on potential chelation agents and indicators of Alzheimer's disease

RSC Advances ◽  
2020 ◽  
Vol 10 (58) ◽  
pp. 35574-35581
Author(s):  
Bryan Wang ◽  
Xuan Luo
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Human Serum ◽  
Blood Brain Barrier ◽  
First Principles ◽  
Brain Barrier ◽  
Serum Transferrin ◽  
Human Serum Transferrin ◽  
First Principles Study ◽  
Blood Brain

Human-serum transferrin is involved in the transportation of aluminum across the blood–brain barrier.

scholarly journals Probable Causes of Alzheimer’s Disease

Sci ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 16
Author(s):  
James David Adams
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Lactic Acid ◽  
Blood Brain Barrier ◽  
Transient Receptor Potential ◽  
Brain Barrier ◽  
Folate Intake ◽  
Blood Brain ◽  
Age Related ◽  
The Brain

A three-part mechanism is proposed for the induction of Alzheimer’s disease: (1) decreased blood lactic acid; (2) increased blood ceramide and adipokines; (3) decreased blood folic acid. The age-related nature of these mechanisms comes from age-associated decreased muscle mass, increased visceral fat and changes in diet. This mechanism also explains why many people do not develop Alzheimer’s disease. Simple changes in lifestyle and diet can prevent Alzheimer’s disease. Alzheimer’s disease is caused by a cascade of events that culminates in damage to the blood–brain barrier and damage to neurons. The blood–brain barrier keeps toxic molecules out of the brain and retains essential molecules in the brain. Lactic acid is a nutrient to the brain and is produced by exercise. Damage to endothelial cells and pericytes by inadequate lactic acid leads to blood–brain barrier damage and brain damage. Inadequate folate intake and oxidative stress induced by activation of transient receptor potential cation channels and endothelial nitric oxide synthase damage the blood–brain barrier. NAD depletion due to inadequate intake of nicotinamide and alterations in the kynurenine pathway damages neurons. Changes in microRNA levels may be the terminal events that cause neuronal death leading to Alzheimer’s disease. A new mechanism of Alzheimer’s disease induction is presented involving lactic acid, ceramide, IL-1β, tumor necrosis factor α, folate, nicotinamide, kynurenine metabolites and microRNA.

Recent Advances in Targeted Drug Delivery Approaches using Lipidic and Polymeric Nanocarriers for the management of Alzheimer’s Disease

2021 ◽  
Vol 27 ◽  
Author(s):  
Dhara Lakdawala ◽  
Md Abdur Rashid ◽  
Farhan Jalees Ahmad
Keyword(s):  
Alzheimer’S Disease ◽  
Drug Delivery ◽  
Alzheimer's Disease ◽  
Blood Brain Barrier ◽  
Targeted Drug Delivery ◽  
Brain Barrier ◽  
Polymeric Nanocarriers ◽  
Blood Brain ◽  
Targeted Drug ◽  
The Brain

: Drug delivery to the brain has remained a significant challenge in treating neurodegenerative disorders such as Alzheimer's disease due to the presence of the blood-brain barrier, which primarily obstructs the access of drugs and biomolecules into the brain. Several methods to overcome the blood-brain barrier have been employed, such as chemical disruption, surgical intervention, focused ultrasound, intranasal delivery and using nanocarriers. Nanocarrier systems remain the method of choice and have shown promising results over the past decade to achieve better drug targeting. Polymeric nanocarriers and lipidic nanoparticles act as a carrier system providing better encapsulation of drugs, site-specific delivery, increased bioavailability and sustained release of drugs. The surface modifications and functionalization of these nanocarrier systems have greatly facilitated targeted drug delivery. The safety and efficacy of these nanocarrier systems have been ascertained by several in vitro and in vivo models. In the present review, we have elaborated on recent developments of nanoparticles as a drug delivery system for Alzheimer's disease, explicitly focusing on polymeric and lipidic nanoparticles.

scholarly journals Dendrimeric Poly(Epsilon-Lysine) Delivery Systems for the Enhanced Permeability of Flurbiprofen across the Blood-Brain Barrier in Alzheimer’s Disease

2018 ◽  
Vol 19 (10) ◽  
pp. 3224 ◽  
Author(s):  
Shafq Al-azzawi ◽  
Dhafir Masheta ◽  
Anna Guildford ◽  
Gary Phillips ◽  
Matteo Santin
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Blood Brain Barrier ◽  
Solid Phase ◽  
Synthesis Method ◽  
Delivery Systems ◽  
Brain Barrier ◽  
Target Cells ◽  
Target Tissue ◽  
Blood Brain

Alzheimer’s disease (AD) is a progressive brain disorder and age-related disease characterised by abnormal accumulation of β-amyloid (Aβ). The development of drugs to combat AD is hampered by the lack of therapeutically-active molecules able to cross the blood-brain barrier (BBB). It is agreed that specifically-designed carriers, such as dendrimers, could support the drug penetration across the BBB. The aim of this study was to design biocompatible and biodegradable dendrimeric delivery systems able to carry Flurbiprofen (FP), as drug for AD treatment, across the BBB and liberate it at the target tissue. These dendrons were synthesised using solid-phase peptide synthesis method and characterised by mass spectrometry and fourier-transform infrared spectroscopy (FTIR). The results revealed successful synthesis of dendrons having FP been integrated during the synthesis at their branching ends. Cytotoxicity assays demonstrated the biocompatibility of the delivery systems, whereas HPLC analysis showed high percentages of permeability across an in vitro BBB model for FP-integrated dendrons. Results also revealed the efficiency of drug conjugates on the γ-secretase enzyme in target cells with evidence of eventual drug release by hydrolysis of the carrier. This study demonstrates that the coupling of FP to dendrimeric delivery systems can successfully be achieved during the synthesis of the poly(epsilon-lysine) macromolecules to improve the transport of the active drug across the BBB.

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