Biomarker May Predict Early Alzheimer’s Disease

Researchers at Sanford Burnham Prebys Medical Discovery Institute (SBP) have identified a peptide that could lead to the early detection of Alzheimer’s disease (AD). The discovery, published in Nature Communications, may also provide a means of homing drugs to diseased areas of the brain to treat AD, Parkinson’s disease, as well as glioblastoma, brain injuries and stroke.

“Our goal was to find a new biomarker for AD,” says Aman Mann, Ph.D., research assistant professor at SBP who shares the lead authorship of the study with Pablo Scodeller, Ph.D., a postdoctoral researcher at SBP. “We have identified a peptide (DAG) that recognizes a protein that is elevated in the brain blood vessels of AD mice and human patients. The DAG target, connective tissue growth factor (CTGF) appears in the AD brain before amyloid plaques, the pathological hallmark of AD.”

“CTGF is a protein that is made in the brain in response to inflammation and tissue repair,” explains Mann. “Our finding that connects elevated levels of CTGF with AD is consistent with the growing body of evidence suggesting that inflammation plays an important role in the development of AD.”

The research team identified the DAG peptide using in vivo phage display screening at different stages of AD development in a mouse model. In young AD mice, DAG detected the earliest stage of the disease. If the early appearance of the DAG target holds true in humans, it would mean that DAG could be used as a tool to identify patients at early, pre-symptomatic stages of the disease when treatments already available may still be effective.

“Importantly, we showed that DAG binds to cells and brain from AD human patients in a CTGF-dependent manner” says Mann. “This is consistent with an earlier report of high CTGF expression in the brains of AD patients.”

“Our findings show that endothelial cells, the cells that form the inner lining of blood vessels, bind our DAG peptide in the parts of the mouse brain affected by the disease,” says Erkki Ruoslahti, M.D., Ph.D., distinguished professor at SBP and senior author of the paper. “This is very significant because the endothelial cells are readily accessible for probes injected into the blood stream, whereas other types of cells in the brain are behind a protective wall called the blood-brain barrier. The change in AD blood vessels gives us an opportunity to create a diagnostic method that can detect AD at the earliest stage possible.

“But first we need to develop an imaging platform for the technology, using MRI or PET scans to differentiate live AD mice from normal mice. Once that’s done successfully, we can focus on humans,” adds Ruoslahti.

“As our research progresses we also foresee CTGF as a potential therapeutic target that is unrelated to amyloid beta (Aβ), the toxic protein that creates brain plaques,” says Ruoslahti. “Given the number of failed clinical studies that have sought to treat AD patients by targeting Aβ, it’s clear that treatments will need to be given earlier—before amyloid plaques appear—or have to target entirely different pathways.

“DAG has the potential to fill both roles—identifying at risk individuals prior to overt signs of AD and targeted delivery of drugs to diseased areas of the brain. Perhaps CTGF itself can be a drug target in AD and other brain disorders linked to inflammation. We’ll just have to learn more about its role in these diseases”.

Stabilizing TREM2 — a potential strategy to combat Alzheimer’s disease

A gene called triggering receptor expressed on myeloid cells 2, or TREM2, has been associated with numerous neurodegenerative diseases, such as Alzheimer’s disease, Frontotemporal lobar degeneration, Parkinson’s disease, and Nasu-Hakola disease. Recently, a rare mutation in the gene has been shown to increase the risk for developing Alzheimer’s disease.

Independently from each other, two research groups have now revealed the molecular mechanism behind this mutation. Their research, published today in EMBO Molecular Medicine, sheds light on the role of TREM2 in normal brain function and suggests a new therapeutic target in Alzheimer’s disease treatment.

Alzheimer’s disease, just like other neurodegenerative diseases, is characterized by the accumulation of specific protein aggregates in the brain. Specialized brain immune cells called microglia strive to counter this process by engulfing the toxic buildup. But as the brain ages, microglia eventually lose out and fail to rid all the damaging material.

TREM2 is active on microglia and enables them to carry out their protective function. The protein spans the microglia cell membrane and uses its external region to detect dying cells or lipids associated with toxic protein aggregates. Subsequently, TREM2 is cut in two. The external part is shed from the protein and released, while the remaining part still present in the cell membrane is degraded. To better understand TREM2 function, the two research groups took a closer look at its cleavage. They were led by Christian Haass at the German Center for Neurodegenerative Diseases at the Ludwig-Maximilians-University in Munich, Germany, and Damian Crowther of AstraZeneca’s IMED Neuroscience group in Cambridge, UK together with colleagues at the Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto and the Cambridge Institute for Medical Research, University of Cambridge, UK.

Using different technological approaches, both groups first determined the exact site of protein shedding and found it to be at amino acid 157. Amino acid 157 was no unknown. Only recently, researchers from China had uncovered that a mutation at this exact position, referred to as p.H157Y, increased the risk of Alzheimer’s disease. Together, these observations indicate that protein cleavage is perturbed in the p.H157 mutant and that this alteration promotes disease development.

As a next step, Haass and Crowther’s groups investigated the biochemical properties of the p.H157Y mutant protein more closely. They found that the mutant was cleaved more rapidly than a healthy version of the protein. “Our results provide a detailed molecular mechanism for how this rare mutation alters the function of TREM2 and hence facilitates the progression of Alzheimer’s disease,” said Crowther.

While most TREM2 mutations affect protein production, the mechanism behind p.H157Y is somewhat different. The p.H157Y mutation allows the protein to be correctly manufactured and transported to the microglia cell surface, but then it is cleaved too quickly. “The end result is the same. In both cases, there is too little full-length TREM protein on microglia,” said Haass. “This suggests that stabilizing TREM2, by making it less susceptible to cleavage, may be a viable therapeutic strategy.”

Diagnostic biomarkers in saliva show promise in recognizing early Alzheimer’s disease

Your spit may hold a clue to future brain health. Investigators at the Beaumont Research Institute, part of Beaumont Health in Michigan, are hopeful that their study involving small molecules in saliva will help identify those at risk of developing Alzheimer’s disease – a neurologic condition predicted to reach epidemic proportions worldwide by 2050.

Their study, “Diagnostic Biomarkers of Alzheimer’s Disease as Identified in Saliva using 1H NMR-Based Metabolomics” was published in the Journal of Alzheimer’s Disease 58(2) on May 16.

Investigators found salivary molecules hold promise as reliable diagnostic biomarkers. The study exemplifies the quest by scientists to combat Alzheimer’s disease, a degenerative brain disorder with no cure and few reliable diagnostic tests. In the United States, Alzheimer’s is a health epidemic affecting more than 5 million Americans. Investigators seek to develop valid and reliable biomarkers, diagnosing the disease in its earliest stages before brain damage occurs and dementia begins.

Researcher Stewart Graham, Ph.D., said, “We used metabolomics, a newer technique to study molecules involved in metabolism. Our goal was to find unique patterns of molecules in the saliva of our study participants that could be used to diagnose Alzheimer’s disease in the earliest stages, when treatment is considered most effective. Presently, therapies for Alzheimer’s are initiated only after a patient is diagnosed and treatments offer modest benefits.”

Metabolomics is used in medicine and biology for the study of living organisms. It measures large numbers of naturally occurring small molecules, called metabolites, present in the blood, saliva and tissues. The pattern or fingerprint of metabolites in the biological sample can be used to learn about the health of the organism.

“Our team’s study demonstrates the potential for using metabolomics and saliva for the early diagnosis of Alzheimer’s disease,” explained Dr. Graham. “Given the ease and convenience of collecting saliva, the development of accurate and sensitive biomarkers would be ideal for screening those at greatest risk of developing Alzheimer’s. In fact, unlike blood or cerebrospinal fluid, saliva is one of the most noninvasive means of getting cellular samples and it’s also inexpensive.”

The study participants included 29 adults in three groups: mild cognitive impairment, Alzheimer’s disease and a control group. After specimens were collected, the researchers positively identified and accurately quantified 57 metabolites. Some of the observed variances in the biomarkers were significant. From their data, they were able to make predictions as to those at most risk of developing Alzheimer’s. Said Dr. Graham, “Worldwide, the development of valid and reliable biomarkers for Alzheimer’s disease is considered the No. 1 priority for most national dementia strategies. It’s a necessary first step to design prevention and early-intervention research studies.”

As Americans age, the number of people affected by Alzheimer’s is rising dramatically. According to the Alzheimer’s Association, by 2050, it’s estimated the number of Americans living with Alzheimer’s disease will triple to about 15-16 million.

Alzheimer’s disease is a type of dementia affecting a person’s ability to think, communicate and function. It greatly impacts their relationships, their independence and lifestyle. The condition’s toll not only affects millions of Americans, but in 2017, it could cost the nation $259 billion.

Georgetown Clinical Trial of Nilotinib in Alzheimer’s Disease Begins

 A clinical trial to examine the effect of nilotinib on clinical outcomes and biomarkers in people with mild to moderate Alzheimer’s disease has opened at Georgetown University Medical Center (GUMC).

The clinical trial is a phase II, randomized, double blinded, placebo-controlled study to evaluate the impact of low doses of the cancer drug(Tasigna®). GUMC is conducting the study with its clinical partner, MedStar Georgetown University Hospital.

The rationale for using nilotinib is based on laboratory and clinical research conducted by the Georgetown Translational Neurotherapeutics Program (TNP). Nilotinib appears to aid in the clearance of accumulated beta-amyloid (Abeta) plaques and Tau tangles in the brain. Both are hallmarks of Alzheimer’s disease. Nilotinib appears to penetrate the blood-brain barrier and turn on the “garbage disposal” machinery inside neurons (a process known as autophagy) to clear the Tau, Abeta and other toxic proteins.

“In a 2015 proof of concept study at Georgetown, patients with Parkinson’s disease or dementia with Lewy bodies were treated with nilotinib. As my colleagues reported, those who completed the study had a reversal in disease progression, observed both clinically and in key biomarkers—the same biomarkers seen in Alzheimer’s,” explains Scott Turner, MD, PhD, medical co-director of the TNP, who will serve as principal investigator for the study. “But even before the Parkinson’s study, research in the laboratory strongly supported studying this drug in people with Alzheimer’s. The promising results of the Parkinson’s study give an even stronger rationale.”

“When used in higher doses for chronic myelogenous leukemia (CML), nilotinib forces cancer cells into autophagy or cell death. The dose used in CML treatment is significantly higher than what we will use in our Alzheimer’s study,” says Charbel Moussa, MB, PhD, scientific and clinical research director for the Translational Neurotherapeutics Program. “When used in smaller doses once a day, as in this study, it appears nilotinib turns on autophagy for about four to eight hours—long enough to clean out the cells without causing cell death. Toxic proteins that build up again then appear to be cleared when the drug is given again the next day.”

Moussa initially conducted the preclinical research that led to the discovery of nilotinib for the potential treatment of neurodegenerative diseases.

Moussa is an inventor on a US patent owned by Georgetown University and on other pending US and foreign patent applications for use of nilotinib and other tyrosine kinase inhibitors for the treatment of neurodegenerative diseases.

The Alzheimer’s Drug Discovery Foundation is supporting this clinical trial through a $2.1 million grant to Turner. The study has also received private philanthropic support.

Turner conducts additional clinical research supported by funding to Georgetown University from Lilly, Biogen, Merck, Acadia, and Toyama as well as the National Institutes of Health and Department of Defense.

To learn more about this clinical trial, please click here. To learn about other Alzheimer’s clinical studies, please visit the Georgetown Memory Disorders Program website.

Dysfunction In Neuronal Transport Mechanism Linked To Alzheimer’s Disease

Researchers at University of California San Diego School of Medicine have confirmed that mutation-caused dysfunction in a process cells use to transport molecules within the cell plays a previously suspected but underappreciated role in promoting the heritable form of Alzheimer’s disease (AD), but also one that might be remedied with existing therapeutic enzyme inhibitors.

The findings published in the October 11 online issue of Cell Reports.

“Our results further illuminate the complex processes involved in the degradation and decline of neurons, which is, of course, the essential characteristic and cause of AD,” said the study’s senior author Larry Goldstein, PhD, Distinguished Professor in the Departments of Neuroscience and Cellular and Molecular Medicine at UC San Diego School of Medicine and director of both the UC San Diego Stem Cell Program and Sanford Stem Cell Clinical Center at UC San Diego Health. “But beyond that, they point to a new target and therapy for a condition that currently has no proven treatment or cure.”

Alzheimer’s disease is a neurodegenerative disorder characterized by progressive memory loss and cognitive dysfunction. It affects more than 30 million people worldwide, including an estimated 5.4 million Americans. One in 10 persons over the age of 65 has AD; one in three over the age of 85. There are currently no treatments proven to cure or reduce the progression of AD.

Genetically, AD is divided into two groups: the much more common sporadic (sAD) form of the disease in which the underlying primary cause is not known and the rarer familial (fAD) form, produced by inherited genetic mutations. In both forms, the brains of AD patients feature accumulations of protein plaques and neurofibrillary tangles that lead to neuronal impairment and eventual cell death.

The prevailing “amyloid cascade hypothesis” posits that these plaques and tangles are comprised, respectively, of amyloid precursor protein (APP) fragments and tau proteins that fuel cellular stress, neurotoxicity, loss of function and cell death. There has been some evidence, however, of another disease-driver: defects in endocytic trafficking — the process by which cells package large, external molecules into vesicles or membrane-bound sacs for transport into the cell for a variety of reasons or uses.

But previous research focused on non-neuronal cells and did not examine the effects of normal expression levels of AD-related proteins, leaving it unclear to what degree decreased endocytosis and other molecular movement within cells played a causative role.

Goldstein and colleagues analyzed neurons created from induced pluripotent stem cells in which they generated PS1 and APP mutations characteristic of fAD using the emerging genome editing technologies CRISPR and TALEN. In this “disease-in-a-dish” approach, they found that the mutated neurons displayed altered distribution and trafficking of APP and internalized lipoproteins (proteins that combine with or transport fat and other lipids in blood plasma). Specifically, there were elevated levels of APP in the soma or cell body while levels were reduced in the neuronal axons.

In previous work, Goldstein’s team had demonstrated that PS1 and APP mutations impaired the activity of specific cellular enzymes. In the latest work, they found that treating mutated fAD neurons with a beta-secretase inhibitor rescued both endocytosis and transcytosis (molecule movement within a cell) functions.

New Clinical Trial Will Test Cancer Drug As Alzheimer’S Treatment

The Alzheimer’s Drug Discovery Foundation (ADDF) announces a $2.1 million grant awarded to R. Scott Turner, MD, PhD, of Georgetown University Medical Center to conduct a phase II clinical trial of low-dose nilotinib (marketed as Tasigna® for use as a cancer therapy) in patients with Alzheimer’s disease.

Nilotinib is an FDA-approved drug for the treatment of adult chronic myeloid leukemia. In preclinical studies conducted by Georgetown researchers, nilotinib reduced cognitive impairment by targeting two of the underlying causes of Alzheimer’s—neuroinflammation and misfolded proteins. Nilotinib triggers a process (called autophagy) that removes the toxic proteins tau and beta-amyloid from the brain before they accumulate into plaques and tangles.

Dr. Turner, co-medical director of Georgetown University Medical Center’s Translational Neurotherapeutics Program (TNP) and director of the Georgetown Memory Disorders Program, says, “By stimulating the brain’s normal autophagic process, which clears out these misfolded proteins in cells, we hope to prevent or slow the progression of Alzheimer’s. In fact, nilotinib may be a first—a broad-spectrum anti-neurodegenerative drug that targets all misfolded protein aggregates that accumulate in the brain of Alzheimer’s patients. By targeting both amyloid and tau, this study may point the way to a new strategy in Alzheimer’s disease treatment.”

The preclinical research was conducted by Charbel Moussa, MD, PhD, scientific and clinical research director for Georgetown’s TNP, who explains, “Nilotinib seems to activate the cell’s garbage disposal machine, reduce plaques and tangles and reverse cognitive decline in animal models of Alzheimer’s disease. We hope that this trial will clarify the effects of nilotinib in Alzheimer’s patients.” Moussa will be a co-investigator on the Alzheimer’s trial.

The trial is expected to start this year and will include 42 patients, with half randomized to receive an escalating dose of nilotinib, while the other half receives a placebo. The primary objectives of the study will be to test the drug’s safety and tolerability and to measure whether nilotinib reduces inflammation and the presence of beta-amyloid and tau in spinal fluid. Dr. Turner and his colleagues in the Georgetown Memory Disorders Program will also perform cognitive and functional abilities tests.

Dr. Howard Fillit, Founding Executive Director and Chief Science Officer of the ADDF, says: “The ADDF is proud to support a clinical trial that holds such promise for Alzheimer’s patients. This funding is part of our wider initiative to use the knowledge gained from cancer research to advance effective treatments for Alzheimer’s.”

The ADDF’s initiative “Learning from Cancer to Advance Treatments for Neurodegenerative Diseases” launched in 2015 with a conference held in partnership with the New York Academy of Sciences. Its goal is both to develop new therapies and test existing cancer therapies for their potential in treating Alzheimer’s disease. In addition to the nilotinib trial at Georgetown, this initiative includes funding for drug development projects at Oryzon Genomics, Rodin Therapeutics, and Yuma Therapeutics.

Georgetown Receives FDA Clearance To Conduct Clinical Trial With Nilotinib In Alzheimer’s Disease

Georgetown University Medical Center (GUMC) today announces the U.S. Food and Drug Administration has completed its review of an investigational new drug application (IND) for the use of nilotinib in a phase II clinical trial for patients with mild to moderate Alzheimer’s disease.

The FDA also informed GUMC investigators that the study can proceed. The clinical trial is expected to begin this year at Georgetown University Medical Center with its clinical partner, MedStar Georgetown University Hospital.

The clinical trial is a phase II, randomized, double blinded, placebo-controlled study to evaluate the impact of low doses of nilotinib (sold as Tasigna®) on biomarkers and clinical outcomes in people with mild to moderate Alzheimer’s disease.

The rationale for using nilotinib is based on research conducted at Georgetown and involves clearing the brain of accumulated beta-amyloid (Abeta) plaques and Tau tangles. Both biomarkers are hallmarks of Alzheimer’s disease. Nilotinib appears to penetrate the blood-brain barrier and turn on the “garbage disposal” machinery inside neurons (a process known as autophagy) to clear Tau and Abeta and other toxic proteins.

“In a 2015 small study at Georgetown, patients with Parkinson’s and dementia with Lewy bodies were given nilotinib. As my colleagues reported, all who completed the study had a reversal in disease progression, observed both clinically and in key biomarkers — the same biomarkers seen in Alzheimer’s ,” explains Scott Turner, MD, PhD, co-medical director of Georgetown University Medical Center’s Translational Neurotherapeutics Program and director of the Georgetown Memory Disorders Program, who will lead the Alzheimer’s study. “But even before the Parkinson’s study, research in the laboratory strongly supported studying this drug in people with Alzheimer’s. The promising results of the Parkinson’s study gives an even stronger rationale.”

Charbel Moussa, MD, PhD, conducted the preclinical research that led to the discovery of nilotinib for the treatment of neurodegenerative diseases.

“When used in higher doses for chronic myelogenous leukemia (CML), nilotinib forces cancer cells into autophagy or cell death. The dose used in CML treatment is significantly higher than what we will use in our Alzheimer’s study,” says Moussa, scientific and clinical research director for the Georgetown Translational Neurotherapeutics Program. “When used in smaller doses once a day, as in this study, nilotinib turns on autophagy for about four to eight hours — long enough to clean out the cells without causing cell death. Toxic proteins that build up again will be cleared when the drug is given again the next day.”

Antibiotics Weaken Alzheimer’s Disease Progression Through Changes in the Gut Microbiome

Long-term treatment with broad spectrum antibiotics decreased levels of amyloid plaques, a hallmark of Alzheimer’s disease, and activated inflammatory microglial cells in the brains of mice in a new study by neuroscientists from the University of Chicago.

The study, published July 21, 2016, in Scientific Reports, also showed significant changes in the gut microbiome after antibiotic treatment, suggesting the composition and diversity of bacteria in the gut play an important role in regulating immune system activity that impacts progression of Alzheimer’s disease.

“We’re exploring very new territory in how the gut influences brain health,” said Sangram Sisodia, PhD, Thomas Reynolds Sr. Family Professor of Neurosciences at the University of Chicago and senior author of the study. “This is an area that people who work with neurodegenerative diseases are going to be increasingly interested in, because it could have an influence down the road on treatments.”

Two of the key features of Alzheimer’s disease are the development of amyloidosis, accumulation of amyloid-ß (Aß) peptides in the brain, and inflammation of the microglia, brain cells that perform immune system functions in the central nervous system. Buildup of Aß into plaques plays a central role in the onset of Alzheimer’s, while the severity of neuro-inflammation is believed to influence the rate of cognitive decline from the disease.

For this study, Sisodia and his team administered high doses of broad-spectrum antibiotics to mice over five to six months. At the end of this period, genetic analysis of gut bacteria from the antibiotic-treated mice showed that while the total mass of microbes present was roughly the same as in controls, the diversity of the community changed dramatically. The antibiotic-treated mice also showed more than a two-fold decrease in Aß plaques compared to controls, and a significant elevation in the inflammatory state of microglia in the brain. Levels of important signaling chemicals circulating in the blood were also elevated in the treated mice.

While the mechanisms linking these changes is unclear, the study points to the potential in further research on the gut microbiome’s influence on the brain and nervous system.

“We don’t propose that a long-term course of antibiotics is going to be a treatment—that’s just absurd for a whole number of reasons,” said Myles Minter, PhD, a postdoctoral scholar in the Department of Neurobiology at UChicago and lead author of the study. “But what this study does is allow us to explore further, now that we’re clearly changing the gut microbial population and have new bugs that are more prevalent in mice with altered amyloid deposition after antibiotics.”

The study is the result of one the first collaborations from the Microbiome Center, a joint effort by the University of Chicago, the Marine Biological Laboratory and Argonne National Laboratory to support scientists at all three institutions who are developing new applications and tools to understand and harness the capabilities of microbial systems across different fields. Sisodia, Minter and their team worked with Eugene B. Chang, Martin Boyer Professor of Medicine at UChicago, and Vanessa Leone, PhD, a postdoctoral scholar in Chang’s lab, to analyze the gut microbes of the mice in this study.

Minter said the collaboration was enabling, and highlighted the cross-disciplinary thinking necessary to tackle a seemingly intractable disease like Alzheimer’s. “Once you put ideas together from different fields that have largely long been believed to be segregated from one another, the possibilities are really amazing,” he said.

Sisodia cautioned that while the current study opens new possibilities for understanding the role of the gut microbiome in Alzheimer’s disease, it’s just a beginning step.

“There’s probably not going to be a cure for Alzheimer’s disease for several generations, because we know there are changes occurring in the brain and central nervous system 15 to 20 years before clinical onset,” he said. “We have to find ways to intervene when a patient starts showing clinical signs, and if we learn how changes in gut bacteria affect onset or progression, or how the molecules they produce interact with the nervous system, we could use that to create a new kind of personalized medicine.”

Estrogen Patch in Newly Postmenopausal Women May Reduce Alzheimer’s Risk

Can estrogen preserve brain function and decrease the risk of Alzheimer’s disease when given early in menopause? Newly postmenopausal women who received estrogen via a skin patch had reduced beta-amyloid deposits, the sticky plaques found in the brains of people with Alzheimer’s disease, a Mayo Clinic study published this month in the Journal of Alzheimer’s Disease found. Ultimately, these deposits harm neurons, leading to cognitive problems.

In the study, women with APOE e4 — one form of the most common gene associated with late-onset Alzheimer’s disease — had lower levels of amyloid deposits.

“This study showed, for the first time, that the brain amyloid deposition ─ a hallmark of Alzheimer’s disease ─ is reduced in newly postmenopausal women who received 17beta-Estradiol patch form of hormone therapy,” says lead author Kejal Kantarci, M.D., a Mayo Clinic radiologist. “Women with APOE e4, who have a greater genetic risk for Alzheimer’s disease, particularly benefited from this therapy.”

Menopause is defined as occurring 12 months after a woman’s last menstrual period and marks the end of menstrual cycles. In the U.S., the average age of menopause is 51. A rapid decline in estrogen with menopause may be associated with an increased risk of Alzheimer’s disease risk in women.

The Women’s Health Initiative study by the National Institutes of Health (NIH) reported that menopausal hormone therapy started in women 65 or older increased the risk of dementia. In contrast, the multicenter Kronos Early Estrogen Prevention Study tested the hypothesis that healthy and younger women would respond to menopausal hormone therapy more favorably.

The Mayo Clinic study used data from the Kronos study to determine the effects of menopausal hormone therapy shortly after menopause, during the critical window of rapid estrogen depletion — five to 36 months past menopause. Researchers investigated the brain amyloid deposition in 68 women ages 42 to 59 who participated in the Kronos trial during this critical window. The researchers used positron emission tomography, also known as a PET scan, to look for the brain amyloid deposits three years after the trial ended.

Of the 68 women, 21 received estrogen via a skin patch, 17 received estrogen orally and 30 received a placebo. Amyloid deposition was lower in women who received the patch, compared to the placebo, and the effect was most apparent in women with the APOE e4 genotype. The oral treatment was not associated with lower amyloid deposition.

The authors are seeking funding to perform amyloid PET imaging at eight more Kronos Early Estrogen Prevention study sites around the U.S.

“If our results are confirmed in the larger group of women, this finding has the potential to change the concepts for preventive interventions that drive the Alzheimer’s disease field today,” Dr. Kantarci says. “It also may have a significant impact on women making the decision to use hormone therapy in the early postmenopausal years.”

Sac to the future: Cellular vessels predict likelihood of developing dementia

Researchers at University of California San Diego School of Medicine say tiny micro-vesicle structures used by neurons and other cells to transport materials internally or dispose of them externally carry tell-tale proteins that may help to predict the likelihood of mild cognitive impairment (MCI) developing into full-blown Alzheimer’s disease (AD).

The findings, published online this week in the journal Alzheimer’s & Dementia, represent a quicker and less invasive way to identify impending cognitive decline and begin treatment before progression to established, irreversible dementia.

“MCI is often a transitional stage between normal aging and dementia,” said senior author Robert A. Rissman, PhD, associate professor in the Department of Neurosciences at UC San Diego School of Medicine, director of the Biomarker Core for the Alzheimer’s Disease Cooperative Study (ADCS) and director of the Neuropathology Core and Brain Bank for the UC San Diego Shiley-Marcos Alzheimer’s Disease Research Center. “It’s associated with more minor cognitive impairment and carries an increased risk of developing Alzheimer’s dementia.”

MCI patients progress to AD at rates as high as 10 to 15 percent per year, prompting an increased emphasis upon diagnosing MCI early and developing treatments that can delay or prevent conversion to AD. The need is underscored, write the authors, by the fact that clinical trials of treatments for established AD have thus far failed.

While clinically distinguishable from normal aging and AD, MCI remains nonetheless a complex condition with many and varied causes. “That has prompted great interest in pinpointing underlying biomarkers that can predict the conversion from MCI to AD dementia,” said Rissman. “Finding such biomarkers would also identify persons most likely to be responsive to preventive treatments.”

Currently, the accepted methods for diagnosing preclinical AD patients is to detect protein biomarkers found in cerebrospinal fluid (CSF), in combination with advanced neuroimaging and neuropsychological testing. But CSF sampling involves an invasive, often painful, process. Neuroimaging is expensive. Neuropsychological testing is time-consuming and can often vary from visit to visit.

The new method described in the Alzheimer’s & Dementia study evaluated the potential of exosomes – extremely small vesicles or sacs found in most cell types, including neurons. Exosomes are thought to move materials inside cells and are used to dump cellular trash into the bloodstream for disposal. In the case of disease, Rissman’s group predicted that neuronal derived exosomes (NDEs) would carry damaged or excess proteins and metabolites out of brain cells, among them amyloid and tau biomarker proteins that are strongly associated with AD.

The researchers harvested NDEs from human blood plasma of 60 patients who participated in an 18-month ADCS clinical trial that enrolled MCI patients only. Some of these MCI patients converted to AD over the course of the study and some did not. Rissman’s lab also gathered samples from control patients and samples from known AD patients. They enriched the NDE content of those originating from neurons. The samples represented patients with normal cognitive function, diagnoses of stable MCI and stable AD and patients who had recently transitioned from MCI to AD.

After characterizing NDEs by size, shape and concentration, the researchers compared that data with the different patient cohorts. They found that NDEs carried targeted biomarker proteins, which have previously been found to predict development of AD up to 10 years before onset of clinical symptoms, and correctly distinguished 100 percent of patients with AD from normal cohorts.

Moreover, the researchers showed for the first time that plasma NDEs from AD and MCI patients may propagate tau tangles in the brains of normal mice similar to what is seen in human AD brains. The fact that these NDEs could induce pathological-like structures in “naïve” mice (animals not previously subjected to experiments) suggests that the contents of NDEs are bioactive, said Rissman. It also suggests that released NDEs can be taken up by cells, raising the possibility of NDEs potential for drug delivery.

The development of blood-based biomarkers for AD (and other neurodegenerative diseases) diagnostics could significantly improve the effectiveness and reliability of patient care and future research, said the authors, who encouraged further studies to refine and validate the approach.

Case Western Reserve University Receives NIH Funding to Participate in Launch of Genomics Center on Alzheimer’s Disease

Case Western Reserve University School of Medicine is one of six recipients of a five-year, $10.8 million award from the National Institute on Aging, part of the National Institutes of Health, to establish the Coordinating Center for Genetics and Genomics of Alzheimer’s disease.

The hope is that discovering genetic risk and prevention factors will enable and accelerate development of prevention and treatments.

The project is a joint venture of researchers from the Perelman School of Medicine at the University of Pennsylvania in Philadelphia and five other institutions, including Case Western Reserve. The other four sites are Boston University, Columbia University, the University of Miami, and the Indiana University. It is part of the NIH Alzheimer’s Disease Sequencing Project, a project involving the same six institutions that began in 2012.

The Coordinating Center for Genetics and Genomics of Alzheimer’s disease will include genomic sequence data from thousands of people with Alzheimer’s disease as well as older cognitively normal subjects. Genome sequencing entails mapping out the order of chemical letters in a cell’s DNA. The goal is to identify genes that contribute to or help guard against Alzheimer’s disease. This work is done using highly sophisticated technology and statistical analysis.

“Understanding Alzheimer’s disease requires massive amounts of data,” said Jonathan Haines, PhD, chair of the department of epidemiology and biostatistics, and director of the Institute for Computational Biology at Case Western Reserve University School of Medicine, where much of the data analysis will occur. “By enabling us to create a common database to which potentially hundreds of researchers will have access, this funding will allow critical sharing of information and interpretation, which is essential for making progress against this insidious disease.”

William S. Bush, PhD, assistant professor of epidemiology and biostatistics at the School of Medicine, is participating in the project as well.

Haines and Bush will use their analytical and biomedical informatics expertise in this project in two ways. First, they will analyze the possible effects of multiple genes in helping cause or prevent Alzheimer’s. Second, they will provide guidance in connecting and interpreting the Alzheimer’s data with data from over 30 different databases of biological knowledge. This includes looking at correlations between the Alzheimer’s data and genes for: 1) other traits and medical conditions and 2) more basic biological mechanisms, such as determining if possible Alzheimer’s-related genes are even expressed — active — in the brain. “Placing our new statistical findings within the current understanding of Alzheimer’s disease biology is essential to move towards new therapies and preventions,” said Bush.

The Alzheimer’s Association defines Alzheimer’s as “a type of dementia that causes problems with memory, thinking and behavior. Symptoms usually develop slowly and get worse over time, becoming severe enough to interfere with daily tasks.” It affects as many as five million people age 65 and older in the United States.

Current drugs are only minimally effective in reducing the severity and progression of the disease. There are no known ways to prevent Alzheimer’s disease.

The new center comprises a major part of the NIH’s National Plan to Address Alzheimer’s Disease to prevent and effectively treat Alzheimer’s disease by 2025.

Researchers show the transmission of the genetic disorder HD in normal animals

Mice transplanted with cells grown from a patient suffering from Huntington’s disease (HD) develop the clinical features and brain pathology of that patient, suggests a study published in the latest issue of Acta Neuropathologica by CHA University in Korea, in collaboration with researchers at Université Laval in Québec City, Canada.

“Our findings shed a completely new light onto our current understanding of how HD begins and develops. We believe that they will also lead to the development of a whole new range of therapies for neurodegenerative diseases of the central nervous system”, explains corresponding author of the study Jihwan Song, professor and director of Neural Regeneration and Therapy Group at the CHA Stem Cell Institute of CHA University.

The researchers have now provided further evidence for this new theory by showing that the abnormal protein coded for this genetic disorder can be transmitted to normal animals by the injection of diseased cells into their brain. “This is the first demonstration that cells carrying a genetic disease are capable of spreading into the normal mammalian brain and lead to the manifestation of behavioral abnormalities associated with the disease”, says Francesca Cicchetti, professor at the Université Laval Faculty of Medecine and researcher at Centre de recherche du CHU de Québec-Université Laval.

HD is an inherited chronic degenerative disorder of the brain characterized by major thinking and motor problems as well as psychiatric disturbances. There is no cure for HD and current treatments are of very limited efficacy. It is caused by a single gene abnormality which leads to the production of a mutant form of a protein called huntingtin (mHtt). The production of this protein in a nerve cell eventually kills it but it has long been thought that this protein cannot spread out of the cell and infect and kill neighbouring ones.

However, in recent post mortem analyses of HD patients who received transplants of non-HD tissue in an attempt to repair their brain, the researchers showed that the mHtt can be found in the graft itself. This suggests that the patient with HD transmitted the mHtt from their brain into the transplant.

Genetic Variations that Boost PKC Enzyme Contribute to Alzheimer’s Disease

In Alzheimer’s disease, plaques of amyloid beta protein accumulate in the brain, damaging connections between neurons. Now, researchers at University of California San Diego School of Medicine and Harvard Medical School have found that the enzyme Protein Kinase C (PKC) alpha is necessary for amyloid beta to damage neuronal connections. They also identified genetic variations that enhance PKC alpha activity in patients with Alzheimer’s disease.

The study, published May 10 in Science Signaling, may present a new therapeutic target for the disease.

“Until recently, it was thought that PKC helped cells survive, and that too much PKC activity led to cancer. Based on that assumption, many companies tested PKC inhibitors as drugs to treat cancer, but they didn’t work,” said co-senior author Alexandra Newton, PhD, professor of pharmacology at UC San Diego School of Medicine.

“Instead, we recently found that the opposite is true. PKC serves as the brakes to cell growth and survival, so cancer cells benefit when PKC is inactivated. Now, our latest study reveals that too much PKC activity is also bad, driving neurodegeneration. This means that drugs that failed in clinical trials for cancer may provide a new therapeutic opportunity for Alzheimer’s disease.”

The study was a three-way collaboration between experts in PKC (Newton), neuroscience (Roberto Malinow, MD, PhD, Distinguished Professor of Neurosciences and Neurobiology and holder of the Shiley-Marcos Endowed Chair in Alzheimer’s Disease in Honor of Dr. Leon Thal at UC San Diego School of Medicine) and genomics (Rudolph Tanzi, PhD, professor of neurology at Harvard Medical School).

Malinow’s team found that when mice are missing the PKC alpha gene, neurons functioned normally, even when amyloid beta was present. Then, when they restored PKC alpha, amyloid beta once again impaired neuronal function. In other words, amyloid beta doesn’t inhibit brain function unless PKC alpha is active.

Enter the Tanzi team, which has a database of genetic information for 1,345 people in 410 families with late-onset Alzheimer’s disease. Tanzi and team use this database to look for rare variants — genetic mutations found only in family members with the disease. Here, the team found three variants in one form of the PKC enzyme, PKC alpha that were associated with the disease in five families.

The researchers replicated these three PKC alpha gene variants in laboratory cell lines. In each instance, PKC alpha activity was increased.

While this study surfaced only five families with these rare mutations in the PKC alpha gene, there are many ways to influence PKC alpha’s activity, Newton said. She believes there could be many other inherited genetic variations that indirectly boost or inhibit PKC activity, and therefore also influence a person’s likelihood of developing Alzheimer’s disease.

“Next we want to identify more molecules participating in the pathophysiology,” said Malinow. “The more steps in the mechanism we can understand, the more therapeutic targets we’ll find for Alzheimer’s disease.”

Dysfunctional Endosomes Are An Early Sign of Neurodegeneration

Writing in the April 11 issue of The Journal of Clinical Investigation, researchers at University of California, San Diego School of Medicine say abnormalities in a protein that helps transport and sort materials inside cells are linked to axonal dysfunction and degeneration of neurons in Alzheimer’s disease (AD) and Down syndrome (DS).

“Amyloid plaques and neurofibrillary tangles in the brain are hallmarks of AD patients and people with DS. However, these classical manifestations may only become detectable in late stages of the disease,” said Chengbiao Wu, PhD, associate professor in the Department of Neurosciences at UC San Diego School of Medicine, and director for cellular and molecular biology at the UC San Diego Down Syndrome Center for Research and Treatment. “Effective treatments will have to target earlier changes that take place in the nerve cells, eventually leading to their demise. Our current study highlights the significance of abnormally active Rab5 protein as a key contributor to early development of the disease. We believe this will open new possibilities for understanding the disease and for developing novel and effective therapies.”

The endosome/lysosome or endocytic pathway in cells moves molecules, such as signaling proteins, from the surface or distant regions of a cell into the cell’s body (via compartments called endosomes) or to another type of cell organelle (lysosomes) where they can be recycled. A small molecule called Rab5 plays a key role in regulating these vital processes.

But in AD and DS, the endocytic system does not work properly, though the precise nature of the underlying dysfunction was not understood. In their new paper, Wu and colleagues suggest a major reason is abnormally enlarged versions of Rab5-endosomes, which occur early and precede the onset of dementia and emergence of the amyloid plaques and neurofibrillary tangles that characterize AD and DS.

Specifically, the scientists determined that increased accumulation of amyloid precursor protein (APP) and/or a small portion of APP (β-carboxyl terminal fragment) in neurons, boosts activation of Rab5, causing enlargement of early endosomes and disruption of retrograde axonal transport of nerve growth factors (NGF) signals. As a result, impacted neurons do not function normally.

The findings were based on tests with cultured cells and rodent models.

Interestingly, when researchers introduced a dominant-negative Rab5 mutant in a fruit fly model, APP-induced axonal blockage was reduced.

Wu said the research underscores the fundamental importance of endosomal function in regulating retrograde axonal trafficking, which conveys materials from axon to cell body, and signaling of NGF. He said further studies will be needed to determine whether reducing Rab5 activation prevents or reverses neurodegeneration in AD and DS.