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Mayo Clinic Study: Blood Biomarker Could Mark Severe Cognitive Decline, Quicker Progression Among Parkinson’s Patients

A genetic mutation, known as GBA, that leads to early onset of Parkinson’s disease and severe cognitive impairment (in about 4 to 7 percent of all patients with the disease) also alters how specific lipids, ceramides and glucosylceramides are metabolized. Mayo Clinic researchers have found that Parkinson’s patients who do not carry the genetic mutation also have higher levels of these lipids in the blood. Further, those who had Parkinson’s and high blood levels were also more likely to have cognitive impairment and dementia. The research was recently published online in the journal PLOS ONE.

The discovery could be an important warning for those with Parkinson’s disease. Parkinson’s is the second most common neurodegenerative disease after Alzheimer’s disease. There is no biomarker to tell who is going to develop the disease — and who is going to develop cognitive impairment after developing Parkinson’s, says Michelle Mielke, Ph.D., a Mayo Clinic researcher and first author of the study.

Cognitive impairment is a frequent symptom in Parkinson’s disease and can be even more debilitating for patients and their caregivers than the characteristic motor symptoms. The early identification of Parkinson’s patients at greatest risk of developing dementia is important for preventing or delaying the onset and progression of cognitive symptoms. Changing these blood lipids could be a way to stop the progression of the disease, says Dr. Mielke.

There is a suggestion this blood lipid marker also could help to predict who will develop Parkinson’s disease and this research is ongoing.

“There is currently no cure for Parkinson’s, but the earlier we catch it — the better chance we have to fight it,” says Dr. Mielke. “It’s particularly important we find a biomarker and identify it in the preclinical phase of the disease, before the onset even begins.”

Dr. Mielke’s lab is researching blood-based biomarkers for Parkinson’s disease because blood tests are less invasive and cheaper than a brain scan or spinal tap — other tools used to research the disease.

This work was supported by grants from the National Institute on Aging (U01 AG37526) and from George P. Mitchell and the late Cynthia W. Mitchell. The DEMPARK study was being funded by an unrestricted grant from Novartis and a grant from the International Parkinson Fonds (Deutschland) gGmbH (IPD). The continuation of the study (LANDSCAPE) is part of the Competence Network Degenerative Dementias (KNDD), which is funded by the German Federal Ministry of Education and Research (project number 01GI1008C)).

Study: Plasma Ceramide and Glucosylceramide Metabolism Is Altered in Sporadic Parkinson’s Disease and Associated with Cognitive Impairment: A Pilot Study [PLOS ONE]

Source: Mayo Clinic

Path of Plaque Buildup in Brain Shows Promise as Early Biomarker for Alzheimer’s Disease

The trajectory of amyloid plaque buildup—clumps of abnormal proteins in the brain linked to Alzheimer’s disease—may serve as a more powerful biomarker for early detection of cognitive decline rather than using the total amount to gauge risk, researchers from Penn Medicine’s Department of Radiology suggest in a new study published online July 15 in Neurobiology of Aging.

Amyloid plaque that starts to accumulate relatively early in the temporal lobe, compared to other areas and in particular to the frontal lobe, was associated with cognitively declining participants, the study found. “Knowing that certain brain abnormality patterns are associated with cognitive performance could have pivotal importance for the early detection and management of Alzheimer’s,” said senior author Christos Davatzikos, PhD, professor in the Department of Radiology, the Center for Biomedical Image Computing and Analytics, at the Perelman School of Medicine at the University of Pennsylvania.

Today, memory decline and Alzheimer’s—which 5.4 million Americans live with today—is often assessed with a variety of tools, including physical and bio fluid tests and neuroimaging of total amyloid plaque in the brain. Past studies have linked higher amounts of the plaque in dementia-free people with greater risk for developing the disorder. However, it’s more recently been shown that nearly a third of people with plaque on their brains never showed signs of cognitive decline, raising questions about its specific role in the disease.

Now, Dr. Davatzikos and his Penn colleagues, in collaboration with a team led by Susan M. Resnick, PhD, Chief, Laboratory of Behavioral Neuroscience at the National Institute on Aging (NIA), used Pittsburgh compound B (PiB) brain scans from the Baltimore Longitudinal Study of Aging’s Imaging Study and discovered a stronger association between memory decline and spatial patterns of amyloid plaque progression than the total amyloid burden.

“It appears to be more about the spatial pattern of this plaque progression, and not so much about the total amount found in brains. We saw a difference in the spatial distribution of plaques among cognitive declining and stable patients whose cognitive function had been measured over a 12-year period. They had similar amounts of amyloid plaque, just in different spots,” Dr. Davatzikos said. “This is important because it potentially answers questions about the variability seen in clinical research among patients presenting plaque. It accumulates in different spatial patterns for different patients, and it’s that pattern growth that may determine whether your memory declines.”

The team, including first author Rachel A. Yotter, PhD, a postdoctoral researcher in the Section for Biomedical Image Analysis, retrospectively analyzed the PET PiB scans of 64 patients from the NIA’s Baltimore Longitudinal Study of Aging whose average age was 76 years old. For the study, researchers created a unique picture of patients’ brains by combining and analyzing PET images measuring the density and volume of amyloid plaque and their spatial distribution within the brain. The radiotracer PiB allowed investigators to see amyloid temporal changes in deposition.

Those images were then compared to California Verbal Learning Test (CLVT) scores, among other tests, from the participants to determine the longitudinal cognitive decline. The group was then broken up into two subgroups: the most stable and the most declining individuals (26 participants).

Despite lack of significant difference in the total amount of amyloid in the brain, the spatial patterns between the two groups (stable and declining) were different, with the former showing relatively early accumulation in the frontal lobes and the latter in the temporal lobes.

A particular area of the brain may be affected early or later depending on the amyloid trajectory, according to the authors, which in turn would affect cognitive impairment. Areas affected early with the plaque include the lateral temporal and parietal regions, with sparing of the occipital lobe and motor cortices until later in disease progression.

“This finding has broad implications for our understanding of the relationship between cognitive decline and resistance and amyloid plaque location, as well as the use of amyloid imaging as a biomarker in research and the clinic,” said Dr Davatzikos. “The next step is to investigate more individuals with mild cognitive impairment, and to further investigate the follow-up scans of these individuals via the BLSA study, which might shed further light on its relevance for early detection of Alzheimer’s.”

Study: Memory decline shows stronger associations with estimated spatial patterns of amyloid deposition progression than total amyloid burden

Source: EurekAlert!

Alzheimer’s Markers Predict Start of Mental Decline

Scientists at Washington University School of Medicine in St. Louis have helped identify many of the biomarkers for Alzheimer’s disease that could potentially predict which patients will develop the disorder later in life. Now, studying spinal fluid samples and health data from 201 research participants at the Charles F. and Joanne Knight Alzheimer’s Disease Research Center, the researchers have shown the markers are accurate predictors of Alzheimer’s years before symptoms develop.

“We wanted to see if one marker was better than the other in predicting which of our participants would get cognitive impairment and when they would get it,” said Catherine Roe, PhD, research assistant professor of neurology. “We found no differences in the accuracy of the biomarkers.”

The study, supported in part by the National Institute on Aging, appears in Neurology.

The researchers evaluated markers such as the buildup of amyloid plaques in the brain, newly visible thanks to an imaging agent developed in the last decade; levels of various proteins in the cerebrospinal fluid, such as the amyloid fragments that are the principal ingredient of brain plaques; and the ratios of one protein to another in the cerebrospinal fluid, such as different forms of the brain cell structural protein tau.

The markers were studied in volunteers whose ages ranged from 45 to 88. On average, the data available on study participants spanned four years, with the longest recorded over 7.5 years.

The researchers found that all of the markers were equally good at identifying subjects who were likely to develop cognitive problems and at predicting how soon they would become noticeably impaired.

Next, the scientists paired the biomarkers data with demographic information, testing to see if sex, age, race, education and other factors could improve their predictions.

“Sex, age and race all helped to predict who would develop cognitive impairment,” Roe said. “Older participants, men and African Americans were more likely to become cognitively impaired than those who were younger, female and Caucasian.”

Roe described the findings as providing more evidence that scientists can detect Alzheimer’s disease years before memory loss and cognitive decline become apparent.

“We can better predict future cognitive impairment when we combine biomarkers with patient characteristics,” she said. “Knowing how accurate biomarkers are is important if we are going to some day be able to treat Alzheimer’s before symptoms and slow or prevent the disease.”

Clinical trials are already underway at Washington University and elsewhere to determine if treatments prior to symptoms can prevent or delay inherited forms of Alzheimer’s disease. Reliable biomarkers for Alzheimer’s should one day make it possible to test the most successful treatments in the much more common sporadic forms of Alzheimer’s.

Study: Amyloid imaging and CSF biomarkers in predicting cognitive impairment up to 7.5 years later

Source: EurekAlert!

Emerging Biomarker Links Social Inequities to Poor Health

It is well known that socioeconomic factors such as poverty and low education play a role in health, but new research released last month at the American Public Health Association’s 140th Annual Meeting in San Francisco, Calif., shows this association is also seen in biomarkers of the blood.

Alzheimer’s Association Awards Largest Ever Research Grant to DIAN for Innovative Therapy Trials

The Alzheimer’s Association announced recently the awarding of its largest ever research grant – nearly $4.2 million over four years – to the Dominantly Inherited Alzheimer’s Network–Therapeutic Trials Unit (DIAN-TTU), based at Washington University School of Medicine in St. Louis, to enable the program to move forward more quickly with innovative drug and biomarker trials in people with genetically-based, young-onset Alzheimer’s disease.