scholarly journals Neurotrophic signaling deficiency exacerbates environmental risks for Alzheimer’s disease pathogenesis

2021 ◽  
Vol 118 (25) ◽  
pp. e2100986118
Author(s):  
Zhourui Wu ◽  
Chun Chen ◽  
Seong Su Kang ◽  
Xia Liu ◽  
Xiaohuan Gu ◽  
...  
Keyword(s):  
Risk Factors ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Senile Plaque ◽  
Neuronal Loss ◽  
Cerebral Hypoperfusion ◽  
Amyloid Aggregates ◽  
Environmental Events ◽  
Neurotrophic Signaling ◽  
Insight Into

The molecular mechanism of Alzheimer’s disease (AD) pathogenesis remains obscure. Life and/or environmental events, such as traumatic brain injury (TBI), high-fat diet (HFD), and chronic cerebral hypoperfusion (CCH), are proposed exogenous risk factors for AD. BDNF/TrkB, an essential neurotrophic signaling for synaptic plasticity and neuronal survival, are reduced in the aged brain and in AD patients. Here, we show that environmental factors activate C/EBPβ, an inflammatory transcription factor, which subsequently up-regulates δ-secretase that simultaneously cleaves both APP and Tau, triggering AD neuropathological changes. These adverse effects are additively exacerbated in BDNF+/− or TrkB+/− mice. Strikingly, TBI provokes both senile plaque deposit and neurofibrillary tangles (NFT) formation in TrkB+/− mice, associated with augmented neuroinflammation and extensive neuronal loss, leading to cognitive deficits. Depletion of C/EBPβ inhibits TBI-induced AD-like pathologies in these mice. Remarkably, amyloid aggregates and NFT are tempospatially distributed in TrkB+/− mice brains after TBI, providing insight into their spreading in the progression of AD-like pathologies. Hence, our study revealed the roles of exogenous (TBI, HFD, and CCH) and endogenous (TrkB/BDNF) risk factors in the onset of AD-associated pathologies.

scholarly journals Role of Oxidative Stress and Metal Toxicity in the Progression of Alzheimer’s Disease

2020 ◽  
Vol 18 (7) ◽  
pp. 552-562 ◽  
Author(s):  
Hareram Birla ◽  
Tarun Minocha ◽  
Gaurav Kumar ◽  
Anamika Misra ◽  
Sandeep Kumar Singh
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Defense Mechanism ◽  
Senile Plaque ◽  
Radical Scavenging ◽  
Neuronal Loss ◽  
The Elderly ◽  
Underlying Mechanism

Alzheimer’s disease (AD) is one of the life-threatening neurodegenerative disorders in the elderly (>60 years) and incurable across the globe to date. AD is caused by the involvement of various genetic, environmental and lifestyle factors that affect neuronal cells to degenerate over the period of time. The oxidative stress is engaged in the pathogenesis of various disorders and its key role is also linked to the etiology of AD. AD is attributed by neuronal loss, abnormal accumulation of Amyloid-β (Aβ) and neurofibrillary tangles (NFTs) with severe memory impairments and other cognitive dysfunctions which lead to the loss of synapses and neuronal death and eventual demise of the individual. Increased production of reactive oxygen species (ROS), loss of mitochondrial function, altered metal homeostasis, aberrant accumulation of senile plaque and mitigated antioxidant defense mechanism all are indulged in the progression of AD. In spite of recent advances in biomedical research, the underlying mechanism of disruption of redox balance and the actual source of oxidative stress is still obscure. This review highlights the generation of ROS through different mechanisms, the role of some important metals in the progression of AD and free radical scavenging by endogenous molecule and supplementation of nutrients in AD.

scholarly journals Investigation of common risk factors between polycystic ovary syndrome and Alzheimer's disease

2021 ◽  
Author(s):  
Nahid Sarahian ◽  
Hosna Sarvazad ◽  
Elham Sajadi ◽  
Nasrin Rahnejat ◽  
Narges Eskandari-Roozbahani
Keyword(s):  
Risk Factors ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Polycystic Ovary Syndrome ◽  
Neurodegenerative Disorder ◽  
Polycystic Ovary ◽  
Clinical Manifestations ◽  
Neuronal Loss ◽  
Ovary Syndrome ◽  
Common Risk Factors

Abstract The most common endocrine disorder among women is Polycystic ovary syndrome (PCOS), characterized by hyperandrogenism, chronic ovulation, and/or ultrasound evidence of small ovarian cysts. Obesity and insulin resistance are also the main factors influencing the clinical manifestations of this syndrome. High intakes of fat have been linked to more significant cognitive decline in old age, and due to the growing elderly population, maintaining long-term optimal cognitive function is very important. Alzheimer's disease (AD) is the most typical progressive neurodegenerative disorder of the brain, and recent studies suggest a relationship between endocrinal dysregulation and neuronal loss during AD pathology. In this narrative review, the international databases, including Google Scholar, Scopus, PubMed, and Web of Science databases, were searched for retrieving the relevant studies. According to the factors involved in Alzheimer's and PCOS, it seems that both disorders may share some common risk factors. In this study, the relevant studies' summaries were categorized to discuss the possible pathways that may explain the association between Alzheimer's and PCOS signs/symptoms and complications. Future preclinical studies are needed to investigate the exact underlining mechanisms related to PCOS and Alzheimer's association.

Voxel-based morphometry (VBM) analysis in Alzheimer's disease an insight into heterogeneity of cerebral atrophy

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S338-S338
Author(s):  
Akihiko Shiino ◽  
Toshiyuki Watanabe ◽  
Ichiro Akiguchi ◽  
Shigehiro Morikawa ◽  
Toshiro Inubushi ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cerebral Atrophy ◽  
Voxel Based Morphometry ◽  
Insight Into

Elucidating the risk factors for progression from amyloid-negative amnestic mild cognitive impairment to dementia

2020 ◽  
Vol 17 ◽  
Author(s):  
Hyung-Ji Kim ◽  
Jae-Hong Lee ◽  
E-nae Cheong ◽  
Sung-Eun Chung ◽  
Sungyang Jo ◽  
...  
Keyword(s):  
Risk Factors ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Amnestic Mild Cognitive Impairment ◽  
Amyloid Pet ◽  
Clinical Progression ◽  
Amnestic Mci

Background: Amyloid PET allows for the assessment of amyloid β status in the brain, distinguishing true Alzheimer’s disease from Alzheimer’s disease-mimicking conditions. Around 15–20% of patients with clinically probable Alzheimer’s disease have been found to have no significant Alzheimer’s pathology on amyloid PET. However, a limited number of studies had been conducted this subpopulation in terms of clinical progression. Objective: We investigated the risk factors that could affect the progression to dementia in patients with amyloid-negative amnestic mild cognitive impairment (MCI). Methods: This study was a single-institutional, retrospective cohort study of patients over the age of 50 with amyloidnegative amnestic MCI who visited the memory clinic of Asan Medical Center with a follow-up period of more than 36 months. All participants underwent brain magnetic resonance imaging (MRI), detailed neuropsychological testing, and fluorine-18[F18]-florbetaben amyloid PET. Results: During the follow-up period, 39 of 107 patients progressed to dementia from amnestic MCI. In comparison with the stationary group, the progressed group had a more severe impairment in verbal and visual episodic memory function and hippocampal atrophy, which showed an Alzheimer’s disease-like pattern despite the lack of evidence for significant Alzheimer’s disease pathology. Voxel-based morphometric MRI analysis revealed that the progressed group had a reduced gray matter volume in the bilateral cerebellar cortices, right temporal cortex, and bilateral insular cortices. Conclusion: Considering the lack of evidence of amyloid pathology, clinical progression of these subpopulation may be caused by other neuropathologies such as TDP-43, abnormal tau or alpha synuclein that lead to neurodegeneration independent of amyloid-driven pathway. Further prospective studies incorporating biomarkers of Alzheimer’s diseasemimicking dementia are warranted.

Characteristics of Insulin-degrading Enzyme in Alzheimer's Disease: A Meta-Analysis

2018 ◽  
Vol 15 (7) ◽  
pp. 610-617 ◽  
Author(s):  
Huifeng Zhang ◽  
Dan Liu ◽  
Huanhuan Huang ◽  
Yujia Zhao ◽  
Hui Zhou
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Enzyme Activity ◽  
Protein Level ◽  
Senile Plaque ◽  
Meta Analysis ◽  
Cochrane Library ◽  
Insulin Degrading Enzyme ◽  
Degrading Enzyme ◽  
Significant Difference

Background: β-amyloid (Aβ) accumulates abnormally to senile plaque which is the initiator of Alzheimer's disease (AD). As one of the Aβ-degrading enzymes, Insulin-degrading enzyme (IDE) remains controversial for its protein level and activity in Alzheimer's brain. Methods: The electronic databases PubMed, EMBASE, The Cochrane Library, OVID and Sinomed were systemically searched up to Sep. 20th, 2017. And the published case-control or cohort studies were retrieved to perform the meta-analysis. Results: Seven studies for IDE protein level (AD cases = 293; controls = 126), three for mRNA level (AD cases = 138; controls = 81), and three for enzyme activity (AD cases = 123; controls = 75) were pooling together. The IDE protein level was significantly lower in AD cases than in controls (SMD = - 0.47, 95% CI [-0.69, -0.24], p < 0.001), but IDE mRNA and enzyme activity had no significant difference (SMD = 0.02, 95% CI [-0.40, 0.43] and SMD = 0.06, 95% CI [-0.41, 0.53] respectively). Subgroup analyses found that IDE protein level was decreased in both cortex and hippocampus of AD cases (SMD = -0.43, 95% CI [-0.71, -0.16], p = 0.002 and SMD = -0.53, 95% CI [-0.91, -0.15], p = 0.006 respectively). However, IDE mRNA was higher in cortex of AD cases (SMD = 0.71, 95% CI [0.14, 1.29], p = 0.01), not in hippocampus (SMD = -0.26, 95% CI [-0.58, 0.06]). Conclusions: Our results indicate that AD patients may have lower IDE protease level. Further relevant studies are still needed to verify whether IDE is one of the factors affecting Aβ abnormal accumulation and throw new insights for AD detection or therapy.

Biological Signatures of Alzheimer’s Disease

2020 ◽  
Vol 20 (9) ◽  
pp. 770-781 ◽  
Author(s):  
Poornima Sharma ◽  
Anjali Sharma ◽  
Faizana Fayaz ◽  
Sharad Wakode ◽  
Faheem H. Pottoo
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
White Matter ◽  
Senile Plaque ◽  
Senile Plaques ◽  
Amyloid Deposition ◽  
Immune Defense ◽  
Amyloid Angiopathy ◽  
Microvascular Changes ◽  
Β Amyloid

Alzheimer’s disease (AD) is the most prevalent and severe neurodegenerative disease affecting more than 0.024 billion people globally, more common in women as compared to men. Senile plaques and amyloid deposition are among the main causes of AD. Amyloid deposition is considered as a central event which induces the link between the production of β amyloid and vascular changes. Presence of numerous biomarkers such as cerebral amyloid angiopathy, microvascular changes, senile plaques, changes in white matter, granulovascular degeneration specifies the manifestation of AD while an aggregation of tau protein is considered as a primary marker of AD. Likewise, microvascular changes, activation of microglia (immune defense system of CNS), amyloid-beta aggregation, senile plaque and many more biomarkers are nearly found in all Alzheimer’s patients. It was seen that 70% of Alzheimer’s cases occur due to genetic factors. It has been reported in various studies that apolipoprotein E(APOE) mainly APOE4 is one of the major risk factors for the later onset of AD. Several pathological changes also occur in the white matter which include dilation of the perivascular space, loss of axons, reactive astrocytosis, oligodendrocytes and failure to drain interstitial fluid. In this review, we aim to highlight the various biological signatures associated with the AD which may further help in discovering multitargeting drug therapy.

scholarly journals Continuous and Cyclic Progesterone Differentially Interact with Estradiol in the Regulation of Alzheimer-Like Pathology in Female 3×Transgenic-Alzheimer’s Disease Mice

Endocrinology ◽  
2010 ◽  
Vol 151 (6) ◽  
pp. 2713-2722 ◽  
Author(s):  
Jenna C. Carroll ◽  
Emily R. Rosario ◽  
Angela Villamagna ◽  
Christian J. Pike
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Postmenopausal Women ◽  
Transgenic Mouse Model ◽  
Dependent Behavior ◽  
Potential Efficacy ◽  
Increased Risk ◽  
Neural Interactions ◽  
Β Amyloid ◽  
Insight Into

Depletion of estrogens and progesterone at menopause has been linked to an increased risk for the development of Alzheimer’s disease (AD) in women. A currently controversial literature indicates that although treatment of postmenopausal women with hormone therapy (HT) may reduce the risk of AD, several parameters of HT may limit its potential efficacy and perhaps, even exacerbate AD risk. One such parameter is continuous vs. cyclic delivery of the progestogen component of HT. Recent experimental evidence suggests that continuous progesterone can attenuate neural actions of estradiol (E2). In the present study, we compared the effects of continuous and cyclic progesterone treatment in the presence and absence of E2 in ovariectomized 3×Tg-AD mice, a transgenic mouse model of AD. We found that ovariectomy-induced hormone depletion increases AD-like pathology in female 3×Tg-AD mice, including accumulation of β-amyloid, tau hyperphosphorylation, and impaired hippocampal-dependent behavior. E2 treatment alone prevents the increases in pathology. Continuous progesterone did not affect β-amyloid levels when delivered alone but blocked the Aβ-lowering action of E2. In contrast, cyclic progesterone significantly reduced β-amyloid levels by itself and enhanced rather than inhibited the E2 effects. These results provide new insight into the neural interactions between E2 and progesterone that may prove valuable in optimizing HT regimens in postmenopausal women.

Sign in / Sign up

Export Citation Format

Share Document