The scientists from the University of California Irvine discovered that reducing the amount of protein TOM-1 in Alzheimer’s rodent models increased pathology, which included increased inflammation, and exacerbated cognitive problems associated with the disease and restoring TOM-1 levels reversed those effects.
This research is significant as it explores the molecular pathways underlying Alzheimer’s disease. It also provides information about the TOM-1 signaling pathway and its role in interleukin-1β mediated inflammation in the brain. This provides a new therapeutic target to treat Alzheimer’s disease
Researchers at the Complutense University of Madrid (UCM) have identified changes in retinal layer thickness, inflammation or thinning in patients with mild Alzheimer’s disease. These changes are identified with non invasive assessment using optical coherence tomography may be an important biomarker for early diagnosis.
Researchers observed that in some patients diagnosed with Alzheimer’s disease, the retinal layers presented neurodegeneration, whereas in others they presented neuroinflammation, the stage prior to neurodegeneration, a finding which can be used to diagnose the disease before other tests.
The study was conducted with a group of 19 patients selected from 2124 clinical histories at the San Carlos Hospital Clinic Geriatric Service in Madrid. These patients had very early stage Alzheimer’s disease and did not present any other disease that affected the retina. The study also included a control group comprising 24 volunteers similar in age and other characteristics but without any relevant disease. The results of this investigation has been published in Scientific Reports.
Early diagnosis of Alzheimer’s is important as treatments and interventions are more effective early in the course of the disease. However, early diagnosis has proven to be challenging. Research has linked the disease process to changes in metabolism, as shown by glucose uptake in certain regions of the brain, but these changes can be difficult to recognize.
Credit: Radiological Society of North America
“Differences in the pattern of glucose uptake in the brain are very subtle and diffuse,” said study co-author Jae Ho Sohn, M.D., from the Radiology & Biomedical Imaging Department at the University of California in San Francisco (UCSF). “People are good at finding specific biomarkers of disease, but metabolic changes represent a more global and subtle process.”
The researchers trained the deep learning algorithm on a special imaging technology known as 18-F-fluorodeoxyglucose positron emission tomography (FDG-PET). In an FDG-PET scan, FDG, a radioactive glucose compound, is injected into the blood. PET scans can then measure the uptake of FDG in brain cells, an indicator of metabolic activity.
The researchers had access to data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI), a major multi-site study focused on clinical trials to improve the prevention and treatment of this disease. The ADNI dataset included more than 2,100 FDG-PET brain images from 1,002 patients. Researchers trained the deep learning algorithm on 90 percent of the dataset and then tested it on the remaining 10 percent of the dataset. Through deep learning, the algorithm was able to teach itself metabolic patterns that corresponded to Alzheimer’s disease.
Finally, the researchers tested the algorithm on an independent set of 40 imaging exams from 40 patients that it had never studied. The algorithm achieved 100 percent sensitivity at detecting the disease an average of more than six years prior to the final diagnosis.
“We were very pleased with the algorithm’s performance,” Dr. Sohn said. “It was able to predict every single case that advanced to Alzheimer’s disease.”
Although he cautioned that their independent test set was small and needs further validation with a larger multi-institutional prospective study, Dr. Sohn said that the algorithm could be a useful tool to complement the work of radiologists especially in conjunction with other biochemical and imaging tests–in providing an opportunity for early therapeutic intervention.
Future research directions include training the deep learning algorithm to look for patterns associated with the accumulation of beta-amyloid and tau proteins, abnormal protein clumps and tangles in the brain that are markers specific to Alzheimer’s disease, according to UCSF’s Youngho Seo, Ph.D., who served as one of the faculty advisors of the study.
Citation: Yiming Ding, Jae Ho Sohn, Michael G. Kawczynski, Hari Trivedi, Roy Harnish, Nathaniel W. Jenkins, Dmytro Lituiev, Timothy P. Copeland, Mariam S. Aboian, Carina Mari Aparici, Spencer C. Behr, Robert R. Flavell, Shih-Ying Huang, Kelly A. Zalocusky, Lorenzo Nardo, Youngho Seo, Randall A. Hawkins, Miguel Hernandez Pampaloni, Dexter Hadley, and Benjamin L. Franc. “A Deep Learning Model to Predict a Diagnosis of Alzheimer Disease by Using 18F-FDG PET of the Brain.” Radiology, 2018, 180958. doi:10.1148/radiol.2018180958.
Researchers suggest that daily intake of nonsteroidal anti-inflammatory drugs like over the counter ibuprofen could prevent the onset of Alzheimer’s disease. This research is led by Dr. Patrick McGeer and is published in the Journal of Alzheimer’s Disease.
Alzheimer’s dementia affects those diagnosed and their family along with a significant financial burden on the society. It is estimated around 47 million people worldwide are affected by this and is the fifth leading cause of death in those aged 65 and above. The Alzheimer’s Association estimates that there are more than 5 million cases in the United States alone. The annual cost United States in 2017 is estimated to be around $259 billion and the projected for the costs go to 1.1 trillion by 2050.
According to the latest publication by Dr. Patrick McGeer diagnosis of people at risk of Alzheimer’s disease is possible with positron-electron microscopy for AD senile plaques, blood or saliva analysis for the elevation of the amyloid-β protein fragment terminating at position 42, and cerebrospinal fluid analysis showing a decrease in the content of this protein. The publication also suggests prevention strategies like self-treatment by consumption of non-steroidal anti-inflammatory drugs, adhering to a Mediterranean diet, and consuming antioxidants such as quercitin which is contained in coffee.
Reference: Mcgeer, Patrick L., and Edith Mcgeer. “Conquering Alzheimer’s Disease by Self Treatment.” Journal of Alzheimers Disease, 2018, 1-3. doi:10.3233/jad-179913.
Researchers from Gladstone Institute uncovered the therapeutic benefits of genetically improving interneurons with a voltage-gated sodium channel Nav1.1 and transplanting them into the brain of a mouse model of Alzheimer’s disease. This study is led by Jorge Palop, Ph.D., an assistant investigator at the Gladstone Institutes. The study findings are published in journal Neuron.
Inhibitory interneurons are essential for managing brain rhythms. They regulate the oscillatory rhythms and network synchrony that are required for cognitive functions. Network dysrhythmias in Alzheimer’s disease and multiple neuropsychiatric disorders are associated with hypofunction of Nav1.1, a voltage-gated sodium channel subunit predominantly expressed in interneurons in Alzheimer’s disease (AD).
Researchers found a way to re-engineer inhibitory interneurons genetically boosted by adding protein Nav1.1 to improve their function. They showed that these enhanced interneurons, when transplanted into the abnormal brain of Alzheimer mice, can properly control the activity of excitatory cells and restore brain rhythms.
The researchers then discovered that the interneurons with enhanced function were able to overcome the toxic disease environment and restore brain function. The findings could eventually lead to the development of new treatment options for patients with Alzheimer’s disease.
In addition to examining if the cell therapy could be translated from mice to humans, researchers are working on pharmaceutical drugs to enhance the function of inhibitory interneurons.
Citation: Martinez-Losa, Magdalena, Tara E. Tracy, Keran Ma, Laure Verret, Alexandra Clemente-Perez, Abdullah S. Khan, Inma Cobos, Kaitlyn Ho, Li Gan, Lennart Mucke, Manuel Alvarez-Dolado, and Jorge J. Palop. “Nav1.1-Overexpressing Interneuron Transplants Restore Brain Rhythms and Cognition in a Mouse Model of Alzheimer’s Disease.” Neuron, 2018. doi:10.1016/j.neuron.2018.02.029.
Research funding: National Institutes of Health, Alzheimer’s Association; S.D. Bechtel, Jr. Foundation.
A new study published in Diabetologia reveals that overweight and obese individuals with early stage type 2 diabetes (T2D) had more severe and progressive abnormalities in brain structure and cognition compared to normal-weight study participants.
The research conducted by Dr Sunjung Yoon and Dr In Kyoon Lyoo (Ewha Brain Institute, Ewha Womens University, Seoul, South Korea), Hanbyul Cho (The Brain Institute, University of Utah, Salt Lake City, UT, USA), and colleagues in Korea and the USA looked into the effects of being overweight or obese on the brains and cognitive functions of people with early stage type 2 diabetes.
The study found that grey matter was significantly thinner in clusters in the temporal, prefrontoparietal, motor and occipital cortices of the brains of diabetic study participants when compared to the non-diabetic control group. Further thinning of the temporal and motor cortices was also observed in the overweight/obese diabetic group, compared to normal-weight diabetics. The team also discovered region-specific changes which suggested that the temporal lobe has a particular vulnerability to the combined effects of having type 2 diabetes and being overweight or obese.
Citation: Yoon, Sujung, Hanbyul Cho, Jungyoon Kim, Do-Wan Lee, Geon Ha Kim, Young Sun Hong, Sohyeon Moon, Shinwon Park, Sunho Lee, Suji Lee, Sujin Bae, Donald C. Simonson, and In Kyoon Lyoo. “Brain changes in overweight/obese and normal-weight adults with type 2 diabetes mellitus.” Diabetologia, 2017. doi:10.1007/s00125-017-4266-7. Adapted from press release by Diabetologia.
In a study of mice and monkeys, NIH funded researchers showed that they could prevent and reverse some of the brain injury caused by the toxic form of a protein called tau.
Scientists used a designer compound to prevent and reverse brain damage caused by tau in mice. Credit: Miller lab, Washington University, St. Louis, MO
The results, published in Science Translational Medicine, suggest that the study of compounds, called tau antisense oligonucleotides, that are genetically engineered to block a cell’s assembly line production of tau, might be pursued as an effective treatment for a variety of disorders. Antisense oligonucleotides are short sequences of DNA or RNA that are programmed to turn genes on or off.
In several disorders, toxic forms of tau clump together inside dying brain cells and form neurofibrillary tangles, including Alzheimer’s disease, tau-associated frontotemporal dementia, chronic traumatic encephalopathy and progressive supranuclear palsy.
Researchers tested sequences designed to turn tau genes off in mice that are genetically engineered to produce abnormally high levels of a mutant form of the human protein. Tau clusters begin to appear in the brains of 6-month-old mice and accumulate with age. The mice develop neurologic problems and die earlier than control mice.
Injections of the tau antisense oligonucleotides into the fluid-filled spaces of the mice brains prevented tau clustering in 6-9-month-old mice and appeared to reverse clustering in older mice. The compound prevented the older mice from losing their ability to build nests. Further experiments on non-human primates suggested that the antisense oligonucleotides tested in mice could reach important areas of larger brains and turn off tau. In comparison with placebo, two spinal tap injections of the compound appeared to reduce tau protein levels in the brains and spinal cords of Cynomologus monkeys. As the researchers saw with the mice, injections of the compound caused almost no side effects.
Currently, researchers are conducting early phase clinical trials on the safety and effectiveness of antisense oligonucleotides designed to treat several neurological disorders, including Huntington’s disease and amyotrophic lateral sclerosis. The U.S. Food and Drug Administration recently approved the use of an antisense oligonucleotide for the treatment of spinal muscular atrophy, a hereditary disorder that weakens the muscles of infants and children.
Citation: DeVos, Sarah L., Rebecca L. Miller, Kathleen M. Schoch, Brandon B. Holmes, Carey S. Kebodeaux, Amy J. Wegener, Guo Chen et al. “Tau reduction prevents neuronal loss and reverses pathological tau deposition and seeding in mice with tauopathy.” Science Translational Medicine 9, no. 374 (2017): eaag0481. DOI: 10.1126/scitranslmed.aag0481 Research funding: National Institutes of Health, Tau Consortium, Cure PSP. Adapted from press release by National Institute of Neurological Disorders and Stroke.
Humans and other vertebrates depend on a portion of the brain called the hippocampus for learning, memory and their sense of location. Nerve cell structures in the adult hippocampus are sustained by factors whose identities have remained largely mysterious so far.
Now, research led by a Johns Hopkins University biologist Dr. Kuruvilla sheds light on the subject, potentially pointing the way to a better understanding of how the structure of nerve cells in the adult hippocampus may deteriorate, which can lead to Alzheimer’s disease and other neurological disorders.
In a paper in the journal Proceedings of the National Academy of Sciences, Kuruvilla and eight other scientists from two research institutions report that a protein that has primarily been studied for its role in early animal development also plays a surprising role in maintaining the structure of hippocampal neurons in adult mice.
The team studied a protein called Wnt5a, which belongs to a family of proteins that have been studied primarily for their functions during embryonic development and in nurturing neurons as the young brain forms. Using mice genetically altered to remove Wnt5a from the hippocampus, the team showed that the protein’s absence did not affect hippocampus development in young mice, but instead resulted in striking degradation of specific nerve cell structures called dendrites, which resemble clusters of tree branches, in adult mice. These findings suggest that the protein plays an important role in maintaining dendrite structures as the mouse ages.
The team went further by showing that when the Wnt5a protein was reintroduced after the dendrites had started to deteriorate in aged mice, the nerve cell structures were restored – to a degree the scientists did not expect.
The team also tested the ability of mice lacking Wnt5a in the hippocampus to perform learning and memory tasks. Behavior tests were run in a Morris Water Maze designed to show how well mice use spatial cues to navigate in a water pool and how long it takes them to learn to use a hidden platform to escape. They found that mutant mice – those without Wnt5a – were poor learners and had attenuated memory; their performance in behavioral tasks became progressively worse with age.
“Together, the findings from the Morris Water Maze test support an essential role for Wnt5a in the acquisition of spatial learning and memory storage in adult animals,” the authors wrote. In the brain, the hippocampus is the seat of short- and long-term memory and governs spatial orientation. Studies have shown that the brains of people with Alzheimer’s disease have structural alterations in dendrites, particularly in the hippocampus.
Kuruvilla said the experiments suggest avenues for further research on what may cause shrinkage of dendrites during neurological disorders. She emphasized, however, that it is premature to extrapolate these results in mice to humans.
While Kuruvilla was careful not to overstate the significance of the findings or how they may apply to cognitive disorders in humans, she said the results at least bring attention to the significance of studying molecular signals that maintain neurons in the adult brain. Compared to the wealth of information on signals that help in formation of neuronal connections in the developing brain, we know far less of how brain structure is sustained in adult life, she said.
Citation: Chih-Ming Chena, Lauren L. Oreficeb, Shu-Ling Chiuc, Tara A. LeGatesa, Samer Hattara, Richard L. Huganirc, Haiqing Zhaoa, Baoji Xub, and Rejji Kuruvillaa. “Wnt5a is essential for hippocampal dendritic maintenance and spatial learning and memory in adult mice.” PNAS 2017. DOI: 10.1073/pnas.1615792114 Research funding: National Institutes of Health. Adapted from press release by Johns Hopkins University.
New research has found concussions accelerate Alzheimer’s disease-related brain atrophy and cognitive decline in people who are at genetic risk for the condition. The findings, which appear in the journal Brain, show promise for detecting the influence of concussion on neurodegeneration.
Brain. Ashton University
Moderate-to-severe traumatic brain injury is one of the strongest environmental risk factors for developing neurodegenerative diseases such as late-onset Alzheimer’s disease, although it is unclear whether mild traumatic brain injury or concussion also increases this risk.
Researchers from Boston University School of Medicine (BUSM) studied 160 Iraq and Afghanistan war veterans, some who had suffered one or more concussions and some who had never had a concussion. Using MRI imaging, the thickness of their cerebral cortex was measured in seven regions that are the first to show atrophy in Alzheimer’s disease, as well as seven control regions.
“We found that having a concussion was associated with lower cortical thickness in brain regions that are the first to be affected in Alzheimer’s disease,” explained corresponding author Jasmeet Hayes, PhD, assistant professor of psychiatry at BUSM and research psychologist at the National Center for PTSD, VA Boston Healthcare System. “Our results suggest that when combined with genetic factors, concussions may be associated with accelerated cortical thickness and memory decline in Alzheimer’s disease relevant areas.”
Of particular note was that these brain abnormalities were found in a relatively young group, with the average age being 32 years old. “These findings show promise for detecting the influence of concussion on neurodegeneration early in one’s lifetime, thus it is important to document the occurrence and subsequent symptoms of a concussion, even if the person reports only having their “bell rung” and is able to shake it off fairly quickly, given that when combined with factors such as genetics, the concussion may produce negative long-term health consequences,” said Hayes.
The researchers hope that others can build upon these findings to find the precise concussion-related mechanisms that accelerate the onset of neurodegenerative diseases such as Alzheimer’s disease, chronic traumatic encephalopathy, Parkinson’s and others. “Treatments may then one day be developed to target those mechanisms and delay the onset of neurodegenerative pathology,” she added.
Citation: Hayes, Jasmeet P., Mark W. Logue, Naomi Sadeh, Jeffrey M. Spielberg, Mieke Verfaellie, Scott M. Hayes, Andrew Reagan, David H. Salat, Erika J. Wolf, Regina E. McGlinchey, William P. Milberg, Annjanette Stone, Steven A. Schichman and Mark W. Miller. ” Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer’s disease.” Brain 2017 vol: 83 pp: aww344. DOI: 10.1093/brain/aww344 Research funding: US Department of Veterans Affairs, NIH/National Institute of Mental Health. Adapted from press release by Boston University School of Medicine.
Researchers have pioneered the technology that detects pathological oligomeric forms of brain tau protein levels in platelets to diagnose Alzheimer’s disease (AD) and other neurodegenerative disorders. More importantly, the ratio between this anomalous tau and the normal tau protein can discriminate Alzheimer’s disease patients from normal controls, and are associated with decreased cognitive impairment. This discovery is published in Journal of Alzheimer’s Disease (JAD). The research findings stems from a fruitful collaboration between the neuroscience laboratory from the International Center for Biomedicine (ICC) under the leadership of Dr. Ricardo Maccioni and the research teams of Drs. Andrea Slachevsky, Faculty of Medicine, University of Chile, together with Drs. Oscar Lopez and James Becker from University of Pittsburgh, School of Medicine, USA.
Credit: IOS press.
These studies open a new avenue in the development of highly sensitive and efficient biomarkers for neurodegenerative disorders. The fact that pathological forms of tau proteins in platelets correlated with decreased brain volume in areas known to be associated with Alzheimer’s disease pathology in the brain is one step forward for the use of peripheral biomarkers, not only for clinical purposes, but also for research studies oriented to understand the complexity of Alzheimer’s disease pathology.
This article, highlighted by Journal of Alzheimer’s Disease, proved that the relationship between the pathological and normal variants of tau were associated with the reduction of cerebral volume in key structures linked with the disease. These structures included the left medial and right anterior cingulate gyri, right cerebellum, right thalamus (pulvinar), left frontal cortex, and right parahippocampal region, in agreement with MRI neuroimaging approaches.
In addition to the enormous utility of this non-invasive technology for the detection and progression of Alzheimer’s disease, the use of a tau biomarker could lead to the identification of Alzheimer’s disease pathology before the clinical symptoms are evident, and it could play an essential role in the development of preventive therapies. Moreover, the determination of peripheral tau markers in platelets can contribute to the understanding of the pathophysiology of multiple neurodegenerative processes where tau proteins play a critical role.
Citation: Slachevsky, Andrea, Leonardo Guzmán-Martínez, Carolina Delgado, Pablo Reyes, Gonzalo A. Farías, Carlos Muñoz-Neira, Eduardo Bravo et al. “Tau Platelets Correlate with Regional Brain Atrophy in Patients with Alzheimer’s Disease.” Journal of Alzheimer’s Disease vol. 55, no. 4, pp. 1595-1603, 2017. DOI: 10.3233/JAD-160652 Adapted from press release by IOS press.