Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0751295 (memory loss)
 3,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alzheimer's disease is a chronic neurodegenerative disorder marked by a progressive loss of memory and cognitive function. Stress level glucocorticoids are correlated with dementia progression in patients with Alzheimer's disease. In this study, twelve month old male mice were chronically treated for 21 days with stress-level dexamethasone (5mg/kg). We investigated the pathological consequences of dexamethasone administration on learning and memory impairments, amyloid precursor protein processing and neuronal cell apoptosis in 12-month old male mice. Our results indicate that dexamethasone can induce learning and memory impairments, neuronal cell apoptosis, and mRNA levels of the amyloid precursor protein, beta-secretase and caspase-3 are selectively increased after dexamethasone administration. Immunohistochemistry demonstrated that amyloid precursor protein, caspase-3 and cytochrome c in the cortex and CA1, CA3 regions of the hippocampus are significantly increased in 12-month old male mice. Furthermore, dexamethasone treatment induced cortex and hippocampus neuron apoptosis as well as increasing the activity of caspase-9 and caspase-3. These findings suggest that high levels of glucocorticoids, found in Alzheimer's disease, are not merely a consequence of the disease process but rather play a central role in the development and progression of Alzheimer's disease. Stress management or pharmacological reduction of glucocorticoids warrant additional consideration of the regimen used in Alzheimer's disease therapies.
 ...
PMID:Glucocorticoids increase impairments in learning and memory due to elevated amyloid precursor protein expression and neuronal apoptosis in 12-month old mice. 1994 64

Alzheimer's disease (AD) is an irreversible neurodegenerative disorder with symptoms of confusion, memory loss, and mood swings. The beta-amyloid peptide, with 39-42 amino acid residues (BAP), plays a significant role in the development of AD. Although there is no cure for AD, it can be managed with available drugs to some degree. Several studies have revealed that natural antioxidants, such as vitamin E, vitamin C and beta-carotene, may help in scavenging free radicals generated during the initiation and progression of this disease. Therefore, there has been considerable interest in plant phytochemicals with antioxidant property as potential agents to prevent the progression of AD. Our earlier investigations of the Withania somnifera fruit afforded lipid peroxidation inhibitory withanamides that are more potent than the commercial antioxidants. In this study, we have tested two major withanamides A (WA) and C (WC) for their ability to protect the PC-12 cells, rat neuronal cells, from beta-amyloid induced cell damage. The cell death caused by beta-amyloid was negated by withanamide treatment. Molecular modeling studies showed that withanamides A and C uniquely bind to the active motif of beta-amyloid (25-35) and suggest that withanamides have the ability to prevent the fibril formation. Further understanding of the mechanism of action and in vivo efficacy of these withanamides may facilitate its development as a prophylaxis.
 ...
PMID:Withanamides in Withania somnifera fruit protect PC-12 cells from beta-amyloid responsible for Alzheimer's disease. 1995 50

Alzheimer's disease (AD) is the major cause of dementia in the elderly, leading to memory loss and cognitive decline. The mechanism underlying onset of the disease has not been fully elucidated. However, characteristic pathological manifestations include extracellular accumulation and aggregation of the amyloid beta-peptide (Abeta) into plaques and intracellular accumulation and aggregation of hyperphosphorylated tau, forming neurofibrillary tangles. Despite extensive research worldwide, no disease modifying treatment is yet available. In this review, we focus on gene therapy as a potential treatment for AD, and summarize recent work in the field, ranging from proof-of-concept studies in animal models to clinical trials. The multifactorial causes of AD offer a variety of possible targets for gene therapy, including two neurotrophic growth factors, nerve growth factor and brain-derived neurotrophic factor, Abeta-degrading enzymes, such as neprilysin, endothelin-converting enzyme and cathepsin B, and AD associated apolipoprotein E. This review also discusses advantages and drawbacks of various rapidly developing virus-mediated gene delivery techniques for gene therapy. Finally, approaches aiming at down-regulating amyloid precursor protein (APP) and beta-site APP cleaving enzyme 1 levels by means of siRNA-mediated knockdown are briefly summarized. Overall, the prospects appear hopeful that gene therapy has the potential to be a disease modifying treatment for AD.
 ...
PMID:Gene therapy in Alzheimer's disease - potential for disease modification. 2015 67

Alzheimer's disease (AD) is a devastating age-related neurodegenerative disorder characterized by progressive impairment of cognition and short-term memory loss. The deposition of amyloid-beta (Abeta) 1-42 into senile plaques is an established feature of AD neuropathology. Controversy still exists about the amyloid pathway as the initiating mechanism or a mere consequence of the events leading to AD. Nevertheless, Abeta toxicity has been probed in vitro and in vivo and increased production or decreased clearance of Abeta peptides are reported to play a major role in the development of AD. Treatment of neural stem cells with Abeta in vitro induces neuronal differentiation. Increased neurogenesis has been also described in AD patients as well as in amyloid-beta protein precursor (AbetaPP) transgenic mice. Adult neurogenesis is greatly enhanced in young AbetaPP transgenic mice, before other AD-liked pathologies, and reduced in older animals. This increased neurogenesis at young ages might be the first pathology related to AD, which is detectable long before other harmful manifestation of the disease. Therefore, understanding the mechanisms of Abeta-induced neurogenesis will reveal insights into the pathogenesis of AD and may prove useful as an early AD biomarker.
 ...
PMID:Adult neurogenesis: a potential tool for early diagnosis in Alzheimer's disease? 2016 55

Multiple intracellular signals are altered in Alzheimer's disease brain tissues, including the PI3K/Akt pathway. However, the pathological relevance of such alterations is poorly understood. In vitro studies yield results that seem to be consistent with the conventional perception in which an up-regulation of the cell survival pathway, PI3K pathway, is protective in Alzheimer's disease pathogenesis. The current in vivo genetic approach, however, reveals that inhibition of the PI3K pathway leads to rescuing of the beta-amyloid peptide (Abeta)-induced memory loss in the Drosophila brain. We began our inquiry into the molecular basis of this memory loss by studying Abeta42-induced enhancement of long-term depression. We found that long-term depression is restored to a normal level through inhibition of PI3K activity. Abeta42-induced PI3K hyperactivity is directly confirmed by immunostaining of the PI3K phosphorylation targets, phospholipids. Such observations lead to the following demonstration that Abeta42-induced memory loss can be rescued through genetic silencing or pharmacological inhibition of PI3K functions. Our data suggest that Abeta42 stimulates PI3K, which in turn causes memory loss in association with an increase in accumulation of Abeta42 aggregates.
 ...
PMID:PI3 kinase signaling is involved in Abeta-induced memory loss in Drosophila. 2035 Dec 82

Amyloid-beta (Abeta) deposition is a defining feature of Alzheimer's disease (AD). The toxicity of Abeta aggregation is thought to contribute to clinical deficits including progressive memory loss and cognitive dysfunction. Therefore, Abeta peptide has become the focus of many therapeutic approaches for the treatment of AD due to its central role in the development of neuropathology of AD. In the past decade, taking the advantage of multiphoton microscopy and molecular probes for amyloid peptide labeling, the dynamic progression of Abeta aggregation in amyloid plaques and cerebral amyloid angiopathy has been monitored in real time in transgenic mouse models of AD. Moreover, amyloid plaque-associated alterations in the brain including dendritic and synaptic abnormalities, changes of neuronal and astrocytic calcium homeostasis, microglial activation and recruitment in the plaque location have been extensively studied. These studies provide remarkable insight to understand the pathogenesis and pathogenicity of amyloid plaques in the context of AD. The ability to longitudinally image plaques and related structures facilitates the evaluation of therapeutic approaches targeting toward the clearance of plaques.
 ...
PMID:Multiphoton in vivo imaging of amyloid in animal models of Alzheimer's disease. 2039 80

The longevity-assurance activity of the tumor suppressor p53 depends on the levels of Delta40p53 (p44), a short and naturally occurring isoform of the p53 gene. As such, increased dosage of p44 in the mouse leads to accelerated aging and short lifespan. Here we show that mice homozygous for a transgene encoding p44 (p44(+/+)) display cognitive decline and synaptic impairment early in life. The synaptic deficits are attributed to hyperactivation of insulin-like growth factor 1 receptor (IGF-1R) signaling and altered metabolism of the microtubule-binding protein tau. In fact, they were rescued by either Igf1r or Mapt haploinsufficiency. When expressing a human or a 'humanized' form of the amyloid precursor protein (APP), p44(+/+) animals developed a selective degeneration of memory-forming and -retrieving areas of the brain, and died prematurely. Mechanistically, the neurodegeneration was caused by both paraptosis- and autophagy-like cell deaths. These results indicate that altered longevity-assurance activity of p53:p44 causes memory loss and neurodegeneration by affecting IGF-1R signaling. Importantly, Igf1r haploinsufficiency was also able to correct the synaptic deficits of APP(695/swe) mice, a model of Alzheimer's disease.
 ...
PMID:Altered longevity-assurance activity of p53:p44 in the mouse causes memory loss, neurodegeneration and premature death. 2040 77

A recent paper by Bialystok et al in Neuropsychologia (vol. 45, pgs. 459 to 464) suggested that early bilingualism produced a statistically significant 4.1-year delay in onset of memory loss symptoms in older individuals with Alzheimer disease, possibly reflecting an increase in the cognitive reserve of these individuals. That study focused on multilingual elderly patients of whom 90% were immigrants. Our memory clinic, in Montreal Canada, has the advantage of having a large set of individuals who are either multilingual immigrants to Canada, or who are nonimmigrants but raised in both official languages of Canada--French and English. We thus attempted to replicate the above findings using a larger cohort in a different setting. We examined age at diagnosis of Alzheimer disease and age at symptom onset for all unilingual versus multilingual participants, and then for those who were nonimmigrant English/French bilinguals. Overall, we found a small but significant protective effect of more than 2 languages spoken, but we found no significant benefit in bilinguals overall in relation to age at diagnosis or age at symptom onset. However, in the immigrant group, the results mirrored those of Bialystok et al with 2 or more languages delaying the diagnosis of Alzheimer disease by almost 5 years. A trend toward the same effect was also seen in nonimmigrants whose first language was French. In contrast, in nonimmigrants whose first language was English, no such effect was found. These results are discussed in relation to the earlier findings and the theory of cognitive reserve.
 ...
PMID:Multilingualism (but not always bilingualism) delays the onset of Alzheimer disease: evidence from a bilingual community. 2050 29

Neurodegenerative diseases encompass a large group of neurological disorders. Clinical symptoms can include memory loss, cognitive impairment, loss of movement or loss of control of movement, and loss of sensation. Symptoms are typically adult onset (although severe cases can occur in adolescents) and are reflective of neuronal and glial cell loss in the central nervous system. Neurodegenerative diseases also are considered progressive, with increased severity of symptoms over time, also reflective of increased neuronal cell death. However, various neurodegenerative diseases differentially affect certain brain regions or neuronal or glial cell types. As an example, Alzheimer disease (AD) primarily affects the temporal lobe, whereas neuronal loss in Parkinson disease (PD) is largely (although not exclusively) confined to the nigrostriatal system. Neuronal loss is almost invariably accompanied by abnormal insoluble aggregates, either intra- or extracellular. Thus, neurodegenerative diseases are categorized by (a) the composite of clinical symptoms, (b) the brain regions or types of brain cells primarily affected, and (c) the types of protein aggregates found in the brain. Here we review the methods by which Drosophila melanogaster has been used to model aspects of polyglutamine diseases, Parkinson disease, and amyotrophic lateral sclerosis and key insights into that have been gained from these models; Alzheimer disease and the tauopathies are covered elsewhere in this special issue.
 ...
PMID:Neurodegenerative models in Drosophila: polyglutamine disorders, Parkinson disease, and amyotrophic lateral sclerosis. 2056 20

While animal experiments have contributed much to our understanding of the mechanisms of Alzheimer's disease (AD), their value in predicting the effectiveness of treatment strategies in clinical trials has remained controversial. The disparity between the results obtained in animal models and clinical trials may in part be explained by limitations of the models and species-specific differences. We propose that one trial passive avoidance in the day-old chick is a useful system to study AD because of the close sequence homologies of chick and human amyloid precursor protein (APP). In the chick, APP is essential for memory consolidation, and disrupting its synthesis or structure results in amnesia. RER, a tripeptide sequence corresponding to part of the growth domain of APP, can restore memory loss and act as a cognitive enhancer. We suggest that RER and its homologues may form the basis for potential pharmacological protection against memory loss in AD.
 ...
PMID:The chick as a model for the study of the cellular mechanisms and potential therapies for Alzheimer's disease. 2072 Dec 85


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>