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BIDMC Researchers Identify Possible Biomarker for Parkinson’s Disease

Although Parkinson’s disease is the second most prevalent neurodegenerative disorder in the U.S., there are no standard clinical tests available to identify this widespread condition. As a result, Parkinson’s disease often goes unrecognized until late in its progression, when the brain’s affected neurons have already been destroyed and telltale motor symptoms such as tremor and rigidity have already appeared.

New Research from SRI Points to Biomarker that Could Track Huntington’s Disease Progression

A hallmark of neurodegenerative diseases such as Alzheimer’s, Parkinson’s and Huntington’s is that by the time symptoms appear, significant brain damage has already occurred—and currently there are no treatments that can reverse it. A team of SRI International researchers has demonstrated that measurements of electrical activity in the brains of mouse models of Huntington’s disease could indicate the presence of disease before the onset of major symptoms. The findings, “Longitudinal Analysis of the Electroencephalogram and Sleep Phenotype in the R6/2 Mouse Model of Huntington’s Disease,” are published in the July 2013 issue of the neurology journal Brain, published by Oxford University Press.

SRI researchers led by Stephen Morairty, Ph.D., a director in the Center for Neuroscience in SRI Biosciences, and Simon Fisher, Ph.D., a postdoctoral fellow at SRI, used electroencephalography (EEG), a noninvasive method commonly used in humans, to measure changes in neuronal electrical activity in a mouse model of Huntington’s disease. Identification of significant changes in the EEG prior to the onset of symptoms would add to evidence that the EEG can be used to identify biomarkers to screen for the presence of a neurodegenerative disease. Further research on such potential biomarkers might one day enable the tracking of disease progression in clinical trials and could facilitate drug development.

“EEG signals are composed of different frequency bands such as delta, theta and gamma, much as light is composed of different frequencies that result in the colors we call red, green and blue,” explained Thomas Kilduff, Ph.D., senior director, Center for Neuroscience, SRI Biosciences. “Our research identified abnormalities in all three of these bands in Huntington’s disease mice. Importantly, the activity in the theta and gamma bands slowed as the disease progressed, indicating that we may be tracking the underlying disease process.”

EEG has shown promise as an indicator of underlying brain dysfunction in neurodegenerative diseases, which otherwise occurs surreptitiously until symptoms appear. Until now, most investigations of EEG in patients with neurodegenerative diseases and in animal models of neurodegenerative diseases have shown significant changes in EEG patterns only after disease symptoms occurred.

“Our breakthrough is that we have found an EEG signature that appears to be a biomarker for the presence of disease in this mouse model of Huntington’s disease that can identify early changes in the brain prior to the onset of behavioral symptoms,” said Morairty, the paper’s senior author. “While the current study focused on Huntington’s disease, many neurodegenerative diseases produce changes in the EEG that are associated with the degenerative process. This is the first step in being able to use the EEG to predict both the presence and progression of neurodegenerative diseases.”

Although previous studies have shown there are distinct and extensive changes in EEG patterns in Alzheimer’s and Huntington’s disease patients, researchers are looking for changes that may occur decades before disease onset.

Huntington’s disease is an inherited disorder that causes certain nerve cells in the brain to die, resulting in motor dysfunction, cognitive decline and psychiatric symptoms. It is the only major neurodegenerative disease where the cause is known with certainty: a genetic mutation that produces a change in a protein that is toxic to neurons.

Study: Longitudinal Analysis of the Electroencephalogram and Sleep Phenotype in the R6/2 Mouse Model of Huntington’s Disease

Source: SRI International

Atrophy in Key Region of Brain Associated with Multiple Sclerosis

Magnetic resonance imaging (MRI) measurements of atrophy in an important area of the brain are an accurate predictor of multiple sclerosis (MS), according to a new study published online in the journal Radiology. According to the researchers, these atrophy measurements offer an improvement over current methods for evaluating patients at risk for MS.

MS develops as the body’s immune system attacks and damages myelin, the protective layer of fatty tissue that surrounds nerve cells within the brain and spinal cord. Symptoms include visual disturbances, muscle weakness and trouble with coordination and balance. People with severe cases can lose the ability to speak or walk.

Approximately 85 percent of people with MS suffer an initial, short-term neurological episode known as clinically isolated syndrome (CIS). A definitive MS diagnosis is based on a combination of factors, including medical history, neurological exams, development of a second clinical attack and detection of new and enlarging lesions with contrast-enhanced or T2-weighted MRI.

“For some time we’ve been trying to understand MRI biomarkers that predict MS development from the first onset of the disease,” said Robert Zivadinov, M.D., Ph.D., FAAN, from the Buffalo Neuroimaging Analysis Center of the University at Buffalo in Buffalo, N.Y. “In the last couple of years, research has become much more focused on the thalamus.”

The thalamus is a structure of gray matter deep within the brain that acts as a kind of relay center for nervous impulses. Recent studies found atrophy of the thalamus in all different MS disease types and detected thalamic volume loss in pediatric MS patients.

“Thalamic atrophy may become a hallmark of how we look at the disease and how we develop drugs to treat it,” Dr. Zivadinov said.

For this study, Dr. Zivadinov and colleagues investigated the association between the development of thalamic atrophy and conversion to clinically definite MS.

“One of the most important reasons for the study was to understand which regions of the brain are most predictive of a second clinical attack,” he said. “No one has really looked at this over the long term in a clinical trial.”

The researchers used contrast-enhanced MRI for initial assessment of 216 CIS patients. They performed follow-up scans at six months, one year and two years. Over two years, 92 of 216 patients, or 42.6 percent, converted to clinically definite MS. Decreases in thalamic volume and increase in lateral ventricle volumes were the only MRI measures independently associated with the development of clinically definite MS.

“First, these results show that atrophy of the thalamus is associated with MS,” Dr. Zivadinov said. “Second, they show that thalamic atrophy is a better predictor of clinically definite MS than accumulation of T2-weighted and contrast-enhanced lesions.”

The findings suggest that measurement of thalamic atrophy and increase in ventricular size may help identify patients at high risk for conversion to clinically definite MS in future clinical trials involving CIS patients.

“Thalamic atrophy is an ideal MRI biomarker because it’s detectable at very early stage,” Dr. Zivadinov said. “It has very good predictive value, and you will see it used more and more in the future.”

The research team continues to follow the study group, with plans to publish results from the four-year follow-up next summer. They are also trying to learn more about the physiology of the thalamic involvement in MS.

“The next step is to look at where the lesions develop over two years with respect to the location of the atrophy,” Dr. Zivadinov said. “Thalamic atrophy cannot be explained entirely by accumulation of lesions; there must be an independent component that leads to loss of thalamus.”

MS affects more than 2 million people worldwide, according to the Multiple Sclerosis International Foundation. There is no cure, but early diagnosis and treatment can slow development of the disease.

Source: Thalamic Atrophy is Associated with Development of Clinically Definite Multiple Sclerosis

Source: EurekAlert!

Biomarkers Could Give Early Warning of Late Heart Transplant Rejection

Researchers at Boston Children’s Hospital have found a combination of biomarkers related to blood vessel and tissue injury that, when measured together, could signal when a transplanted heart is becoming damaged to the point of failure, a process that is often undetected. The markers would give doctors an opportunity to intervene and save a recipient’s heart, and also provide a starting point for identifying long-term rejection biomarkers for several kinds of organ transplants.

Researchers Find Evidence that Brain Compensates after Traumatic Injury

Researchers at Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center have found that a special magnetic resonance imaging (MRI) technique may be able to predict which patients who have experienced concussions will improve. The results, which were presented this week at the annual meeting of the Radiological Society of North America (RSNA), suggest that, in some patients, the brain may change to compensate for the damage caused by the injury.