Current Strategies and Novel Drug Approaches for Alzheimer Disease

2020 ◽  
Vol 19 (9) ◽  
pp. 676-690 ◽  
Author(s):  
Roma Ghai ◽  
Kandasamy Nagarajan ◽  
Meenakshi Arora ◽  
Parul Grover ◽  
Nazakat Ali ◽  
...  

Alzheimer’s Disease (AD) is a chronic, devastating dysfunction of neurons in the brain leading to dementia. It mainly arises due to neuronal injury in the cerebral cortex and hippocampus area of the brain and is clinically manifested as a progressive mental failure, disordered cognitive functions, personality changes, reduced verbal fluency and impairment of speech. The pathology behind AD is the formation of intraneuronal fibrillary tangles, deposition of amyloid plaque and decline in choline acetyltransferase and loss of cholinergic neurons. Tragically, the disease cannot be cured, but its progression can be halted. Various cholinesterase inhibitors available in the market like Tacrine, Donepezil, Galantamine, Rivastigmine, etc. are being used to manage the symptoms of Alzheimer’s disease. The paper’s objective is to throw light not only on the cellular/genetic basis of the disease, but also on the current trends and various strategies of treatment including the use of phytopharmaceuticals and nutraceuticals. Enormous literature survey was conducted and published articles of PubMed, Scifinder, Google Scholar, Clinical Trials.org and Alzheimer Association reports were studied intensively to consolidate the information on the strategies available to combat Alzheimer’s disease. Currently, several strategies are being investigated for the treatment of Alzheimer’s disease. Immunotherapies targeting amyloid-beta plaques, tau protein and neural pathways are undergoing clinical trials. Moreover, antisense oligonucleotide methodologies are being approached as therapies for its management. Phytopharmaceuticals and nutraceuticals are also gaining attention in overcoming the symptoms related to AD. The present review article concludes that novel and traditional therapies simultaneously promise future hope for AD treatment.

Author(s):  
Yegnanarayanan Venkatraman ◽  
◽  
Narayanaa Y Krithicaa ◽  
Valentina E. Balas ◽  
Marius M. Balas ◽  
...  

Notice that the synapsis of brain is a form of communication. As communication demands connectivity, it is not a surprise that "graph theory" is a fastest growing area of research in the life sciences. It attempts to explain the connections and communication between networks of neurons. Alzheimer’s disease (AD) progression in brain is due to a deposition and development of amyloid plaque and the loss of communication between nerve cells. Graph/network theory can provide incredible insights into the incorrect wiring leading to memory loss in a progressive manner. Network in AD is slanted towards investigating the intricate patterns of interconnections found in the pathogenesis of brain. Here, we see how the notions of graph/network theory can be prudently exploited to comprehend the Alzheimer’s disease. We begin with introducing concepts of graph/network theory as a model for specific genetic hubs of the brain regions and cellular signalling. We begin with a brief introduction of prevalence and causes of AD followed by outlining its genetic and signalling pathogenesis. We then present some of the network-applied outcome in assessing the disease-signalling interactions, signal transduction of protein-protein interaction, disturbed genetics and signalling pathways as compelling targets of pathogenesis of the disease.


2019 ◽  
pp. S445-S451 ◽  
Author(s):  
H. Svobodová ◽  
D. Kosnáč ◽  
Z. Balázsiová ◽  
H. Tanila ◽  
P.O. Miettinen ◽  
...  

Iron is very important element for functioning of the brain. Its concentration changes with aging the brain or during disease. The aim of our work was the histological examination of content of ferritin and free iron (unbound) in brain cortex in association with Aβ plaques from their earliest stages of accumulation in amyloid plaque forming APP/PS1 transgenic mice. Light microscopy revealed the onset of plaques formation at 8-monthage. Detectable traces of free iron and no ferritin were found around plaques at this age, while the rate of their accumulation in and around Aβ plaques was elevated at 13 months of age. Ferritin accumulated mainly on the edge of Aβ plaques, while the smaller amount of free iron was observed in the plaque-free tissue, as well as in and around Aβ plaques. We conclude that free iron and ferritin accumulation follows the amyloid plaques formation. Quantification of cortical iron and ferritin content can be an important marker in the diagnosis of Alzheimer’s disease.


2020 ◽  
Vol 21 (9) ◽  
pp. 3270
Author(s):  
Ruth Maron ◽  
Gad Armony ◽  
Michael Tsoory ◽  
Meir Wilchek ◽  
Dan Frenkel ◽  
...  

The two major proteins involved in Alzheimer’s disease (AD) are the amyloid precursor protein (APP) and Tau. Here, we demonstrate that these two proteins can bind to each other. Four possible peptides APP1 (390–412), APP2 (713–730), Tau1 (19–34) and Tau2 (331–348), were predicted to be involved in this interaction, with actual binding confirmed for APP1 and Tau1. In vivo studies were performed in an Alzheimer Disease animal model—APP double transgenic (Tg) 5xFAD—as well as in 5xFAD crossed with Tau transgenic 5xFADXTau (FT), which exhibit declined cognitive reduction at four months of age. Nasal administration of APP1 and Tau1 mixture, three times a week for four or five months, reduced amyloid plaque burden as well as the level of soluble Aβ 1–42 in the brain. The treatment prevented the deterioration of cognitive functions when initiated at the age of three months, before cognitive deficiency was evident, and also at the age of six months, when such deficiencies are already observed, leading to a full regain of cognitive function.


2020 ◽  
Vol 117 (51) ◽  
pp. 32691-32700
Author(s):  
Sonam Dubey ◽  
Stefan Heinen ◽  
Slavica Krantic ◽  
JoAnne McLaurin ◽  
Donald R. Branch ◽  
...  

Preclinical and clinical data support the use of focused ultrasound (FUS), in the presence of intravenously injected microbubbles, to safely and transiently increase the permeability of the blood–brain barrier (BBB). FUS-induced BBB permeability has been shown to enhance the bioavailability of administered intravenous therapeutics to the brain. Ideal therapeutics candidates for this mode of delivery are those capable of inducing benefits peripherally following intravenous injection and in the brain at FUS-targeted areas. In Alzheimer’s disease, intravenous immunoglobulin (IVIg), a fractionated human blood product containing polyclonal antibodies, act as immunomodulator peripherally and centrally, and it can reduce amyloid pathology in the brain. Using the TgCRND8 mouse model of amyloidosis, we tested whether FUS can improve the delivery of IVIg, administered intravenously (0.4 g/kg), to the hippocampus and reach an effective dose to reduce amyloid plaque pathology and promote neurogenesis. Our results show that FUS-induced BBB permeability is required to deliver a significant amount of IVIg (489 ng/mg) to the targeted hippocampus of TgCRN8 mice. Two IVIg-FUS treatments, administered at days 1 and 8, significantly increased hippocampal neurogenesis by 4-, 3-, and 1.5-fold in comparison to saline, IVIg alone, and FUS alone, respectively. Amyloid plaque pathology was significantly reduced in all treatment groups: IVIg alone, FUS alone, and IVIg-FUS. Putative factors promoting neurogenesis in response to IVIg-FUS include the down-regulation of the proinflammatory cytokine TNF-α in the hippocampus. In summary, FUS was required to deliver an effective dose of IVIg to promote hippocampal neurogenesis and modulate the inflammatory milieu.


2020 ◽  
Author(s):  
Simone Mwenda Crivelli ◽  
Qian Luo ◽  
Jo Stevens ◽  
Caterina Giovagnoni ◽  
Daan van Kruining ◽  
...  

Abstract Background: Deregulation of ceramide and sphingomyelin levels have been suggested to contribute to the pathogenesis of Alzheimer’s disease (AD). Ceramide transfer proteins (CERTs) are ceramide carriers, crucial for ceramide and sphingomyelin balance in cells. Extracellular forms of CERTs co-localize with amyloid-β (Aβ) plaques in AD brains. To date, the significance of these observations for the pathophysiology of AD remains uncertain.Methods: The plasmid expressing CERTL, the long isoform of CERTs, was used to study the interaction of CERTL with amyloid precursor protein (APP) by co-immunoprecipitation and immunofluorescence in HEK cells. The recombinant CERTL protein was employed to study interaction of CERTL with amyloid-β (Aβ), Aβ aggregation process in presence of CERTL, and the resulting changes in Aβ toxicity in neuroblastoma cells. CERTL was overexpressed in neurons by adeno associated virus (AAV) in a familial mouse model of familial AD (5xFAD). Ten weeks after transduction animal were challenged with behavior tests for memory, anxiety and locomotion. At week twelve brains were investigated for sphingolipid levels by mass spectrometry, plaques and neuroinflammation by immunohistochemistry, gene expression and/or immunoassay.Results: Here, we report that CERTL, binds to APP, modifies Aβ aggregation and reduces Aβ neurotoxicity in vitro. Furthermore, we show that intracortical injection of AAV, mediating the expression of CERTL, decreases levels of ceramide d18:1/16:0 and increases sphingomyelin levels in the brain of male transgenic mice, modelling familial AD (5xFAD). CERTL in vivo over-expression has a mild effect on animal locomotion and decreases Aβ formation and modulates microglia by decreasing their pro-inflammatory phenotype.Conclusion: Our results demonstrate a crucial role of CERTL in regulating ceramide levels in the brain, in amyloid plaque formation and neuroinflammation, thereby opening research avenues for therapeutic targets of AD and other neurodegenerative diseases.


2016 ◽  
Vol 371 (1700) ◽  
pp. 20150429 ◽  
Author(s):  
Marc Aurel Busche ◽  
Arthur Konnerth

An essential feature of Alzheimer's disease (AD) is the accumulation of amyloid-β (Aβ) peptides in the brain, many years to decades before the onset of overt cognitive symptoms. We suggest that during this very extended early phase of the disease, soluble Aβ oligomers and amyloid plaques alter the function of local neuronal circuits and large-scale networks by disrupting the balance of synaptic excitation and inhibition ( E / I balance) in the brain. The analysis of mouse models of AD revealed that an Aβ-induced change of the E / I balance caused hyperactivity in cortical and hippocampal neurons, a breakdown of slow-wave oscillations, as well as network hypersynchrony. Remarkably, hyperactivity of hippocampal neurons precedes amyloid plaque formation, suggesting that hyperactivity is one of the earliest dysfunctions in the pathophysiological cascade initiated by abnormal Aβ accumulation. Therapeutics that correct the E / I balance in early AD may prevent neuronal dysfunction, widespread cell loss and cognitive impairments associated with later stages of the disease. This article is part of the themed issue ‘Evolution brings Ca 2+ and ATP together to control life and death’.


Author(s):  
You-Hyang Song ◽  
Jiwon Yoon ◽  
Seung-Hee Lee

AbstractSomatostatin (SST) is a well-known neuropeptide that is expressed throughout the brain. In the cortex, SST is expressed in a subset of GABAergic neurons and is known as a protein marker of inhibitory interneurons. Recent studies have identified the key functions of SST in modulating cortical circuits in the brain and cognitive function. Furthermore, reduced expression of SST is a hallmark of various neurological disorders, including Alzheimer’s disease and depression. In this review, we summarize the current knowledge on SST expression and function in the brain. In particular, we describe the physiological roles of SST-positive interneurons in the cortex. We further describe the causal relationship between pathophysiological changes in SST function and various neurological disorders, such as Alzheimer’s disease. Finally, we discuss potential treatments and possibility of novel drug developments for neurological disorders based on the current knowledge on the function of SST and SST analogs in the brain derived from experimental and clinical studies.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Simone M. Crivelli ◽  
Qian Luo ◽  
Jo A.A. Stevens ◽  
Caterina Giovagnoni ◽  
Daan van Kruining ◽  
...  

Abstract Background Dysregulation of ceramide and sphingomyelin levels have been suggested to contribute to the pathogenesis of Alzheimer’s disease (AD). Ceramide transfer proteins (CERTs) are ceramide carriers which are crucial for ceramide and sphingomyelin balance in cells. Extracellular forms of CERTs co-localize with amyloid-β (Aβ) plaques in AD brains. To date, the significance of these observations for the pathophysiology of AD remains uncertain. Methods A plasmid expressing CERTL, the long isoform of CERTs, was used to study the interaction of CERTL with amyloid precursor protein (APP) by co-immunoprecipitation and immunofluorescence in HEK cells. The recombinant CERTL protein was employed to study interaction of CERTL with amyloid-β (Aβ), Aβ aggregation process in presence of CERTL, and the resulting changes in Aβ toxicity in neuroblastoma cells. CERTL was overexpressed in neurons by adeno-associated virus (AAV) in a mouse model of familial AD (5xFAD). Ten weeks after transduction, animals were challenged with behavior tests for memory, anxiety, and locomotion. At week 12, brains were investigated for sphingolipid levels by mass spectrometry, plaques, and neuroinflammation by immunohistochemistry, gene expression, and/or immunoassay. Results Here, we report that CERTL binds to APP, modifies Aβ aggregation, and reduces Aβ neurotoxicity in vitro. Furthermore, we show that intracortical injection of AAV, mediating the expression of CERTL, decreases levels of ceramide d18:1/16:0 and increases sphingomyelin levels in the brain of male 5xFAD mice. CERTL in vivo over-expression has a mild effect on animal locomotion, decreases Aβ formation, and modulates microglia by decreasing their pro-inflammatory phenotype. Conclusion Our results demonstrate a crucial role of CERTL in regulating ceramide levels in the brain, in amyloid plaque formation and neuroinflammation, thereby opening research avenues for therapeutic targets of AD and other neurodegenerative diseases.


2010 ◽  
Vol 2 (1) ◽  
pp. 159-164
Author(s):  
Suman Pratihar ◽  
Shomik Nag ◽  
Jayanta Kumar Kundu

Alzheimer’s disease is a brain disorder named after German physician Alois Alzheimer, who first described it in 1906. The Alzheimer’s disease is now becoming curable by identifying the actual cause of the disease with the proper diagnosis of the disease of the patient. The disease can now be cured by drug treatment, by hormonal treatment and by using herbal products such as medicines. The drugs are based on antagonizing action of the components against the causative agents (â Amyloid plaque, Apolipoprotein E, Tau protein) of the disease. Thecommon drugs based on their action are N-methyl-D-aspartate (NMDA) receptor antagonists, Cholinesterase inhibitor, agents for increasing blood supply and neurotransmitter in the brain, lipofuchsin and â Amyloid plaque inhibitor, free radical scavenger, agent for metal chelator and agent for increasing macrophage activity in the brain.


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