Breaking News
April 22, 2019 - Hyaline fibromatosis syndrome – Genetics Home Reference
April 22, 2019 - Scientists use CRISPR for possible ‘bubble boy’ therapy
April 22, 2019 - Hematologist (and a mom, singer, actress and much more) stands up for diversity
April 22, 2019 - Novel AI voice tool can help diagnose PTSD
April 22, 2019 - Overlooked part of cell’s internal machinery may hold key to treating acute myeloid leukemia
April 22, 2019 - MIT scientists reverse some behavioral symptoms of rare neurodevelopmental disorder
April 22, 2019 - Scientists find new therapy target for drug-induced liver failure
April 22, 2019 - Opioid dose variability could lead to increased risk of overdose, study suggests
April 22, 2019 - Newly developed model predicts salmonella outbreaks several months in advance
April 22, 2019 - Deep-learning model better predicts survival outcomes for lung cancer
April 22, 2019 - One in Three U.S. Adults Aged 35 to 44 May Have Drinking Problem
April 22, 2019 - Why the measles virus is so contagious
April 22, 2019 - Magnet ‘Zap’ to the Brain Might Jumpstart Aging Memory
April 22, 2019 - Immune response to gut microbes may be early indicator of type 1 diabetes
April 22, 2019 - Destination Limbo: Health Suffers Among Asylum Seekers In Crowded Border Shelter
April 22, 2019 - Research shows how dopamine contributes to sex differences in worms
April 22, 2019 - Marijuana users weigh less compared to non-users
April 22, 2019 - Research uncovers critical RNA processing aberrations in ALS and FTD
April 22, 2019 - Many cancer patients use marijuana and prescription opioids, study reveals
April 22, 2019 - Frailty may up fracture risk in patients with type 2 diabetes
April 22, 2019 - Study provides new insight into how obesity, insulin resistance can affect cognition
April 22, 2019 - Study seeks to better understand the genetic causes for hypospadias
April 22, 2019 - FDA grants approval of first generic naloxone nasal spray to treat opioid overdose
April 22, 2019 - FDA authorizes marketing of first medical device to treat ADHD
April 22, 2019 - Vanderbilt researchers to develop and test ‘safe harbor’ standards of care
April 22, 2019 - You’re probably brushing your teeth wrong – here are four tips for better dental health
April 22, 2019 - Pharmacy closures contribute to medication non-adherence among heart patients
April 22, 2019 - Using Edge AI technology to observe behavior of cattle
April 22, 2019 - Bacteria play a role in the development of stomach ulcers in pigs
April 22, 2019 - Hand Hygiene Compliance Poor in Task Transitions
April 22, 2019 - smoking could harm your baby
April 22, 2019 - Scientists identify rare, paradoxical response to antiretroviral therapy
April 21, 2019 - More TV, Tablets, More Attention Issues at Age 5
April 21, 2019 - Drug reduces risk of kidney failure in people with diabetes, study finds
April 21, 2019 - New research identifies novel link between antibiotic resistance and climate change
April 21, 2019 - Simple intervention can provide lasting protection for teens against junk food marketing
April 21, 2019 - The protein p38-gamma identified as a new therapeutic target in liver cancer
April 21, 2019 - Novel system enables researchers to study bacteria within mini-tissues in a dish
April 21, 2019 - Discovery of oral cancer biomarkers could save thousands of lives
April 21, 2019 - Geneva Exhibition committee gives gold medals to two medications developed by Kazan
April 21, 2019 - Scientists aim to minimize or eliminate hair loss during cancer treatment
April 21, 2019 - WiFi interacts with signaling pathways in the human brain
April 21, 2019 - Stroke Hospitalizations Down in Black, White Medicare Enrollees
April 21, 2019 - First common risk genes discovered for autism
April 21, 2019 - Researchers map auditory sensory system of the mouse brain
April 21, 2019 - Scientists Bring Pig’s Brain, Dead 4 Hours, Back to ‘Cellular Activity’
April 21, 2019 - Virtual reality a promising tool for reducing fears and phobia in autism
April 21, 2019 - New analysis lists out opportunities for U.S. medical schools to advance population health
April 21, 2019 - More sleep may help teens with ADHD focus and organize
April 21, 2019 - Breakthrough antibody treatment suppresses HIV without antivirals
April 21, 2019 - AveXis Data Reinforce Effectiveness of Zolgensma in Treating Spinal Muscular Atrophy (SMA) Type 1
April 21, 2019 - Is your hand pain arthritis, carpal tunnel or something else?
April 21, 2019 - Measles outbreaks may become more frequent if vaccination rates continue to decline
April 21, 2019 - Researchers succeed in accelerating process of creating 3D images
April 21, 2019 - Tiny worm mimics key genetic risk for Alzheimer’s
April 21, 2019 - Angry dreams explained by brain waves
April 20, 2019 - Parenteral Antimicrobial Tx at Home Burdens Children’s Caregivers
April 20, 2019 - Diabetes treatment may keep dementia, Alzheimer’s at bay
April 20, 2019 - New bandage-like biosensor collects and analyzes sweat
April 20, 2019 - A comprehensive, centralized database of bovine milk compounds
April 20, 2019 - Two new epigenetic regulators maintain self-renewal of embryonic stem cells
April 20, 2019 - New Evidence That Veggies Beat Steak for Heart Health
April 20, 2019 - Study reveals genes associated with heavy drinking and alcoholism
April 20, 2019 - Texas A&M AgriLife becomes the newest member of NutriRECS international consortium
April 20, 2019 - In most states, insurance won’t cover addiction treatments
April 20, 2019 - Computer-based memory games may be beneficial for individuals with fragile X syndrome
April 20, 2019 - Timing of food intake influences molecular clock in the liver of mice
April 20, 2019 - Precise decoding of breast cancer cells paves way for new treatment option
April 20, 2019 - Scientists use 3D imaging to help model complex processes performed by placenta
April 20, 2019 - MediciNova Announces Plans to Move Forward with a Phase 3 Trial of MN-166 (ibudilast) in ALS
April 20, 2019 - Genetic variants that protect against obesity could aid new weight loss medicines
April 20, 2019 - New technology developed for microscopic imaging in living organisms
April 20, 2019 - when quitting cigarettes, consider using more nicotine, not less
April 20, 2019 - Key proteins can block Listeria without triggering the death of host cells
April 20, 2019 - Researchers create a working model of cerebral tract to study brain function
April 20, 2019 - New study shows that microbes can help break toxic chemical in dust
April 20, 2019 - Scientists use NIR light and injected DNA nanodevice to guide stem cells to injury
April 20, 2019 - Microbial Features ID’d for Pediatric Irritable Bowel Syndrome
April 20, 2019 - Study reveals patterns of drug intoxication deaths, organ donors across the US
April 20, 2019 - Scientists deploy CRISPR gene-editing tool to engineer multiple edits
Researchers measure brain metabolite levels in people with mild memory problems

Researchers measure brain metabolite levels in people with mild memory problems

image_pdfDownload PDFimage_print

Using strong and targeted but noninvasive magnets at specific sites in the brains of people with and without mild learning and memory problems, Johns Hopkins researchers report they were able to detect differences in the concentrations of brain chemicals that transmit messages between neurons. The strength of these magnetic fields allows the researchers to measure tiny amounts and compare multiple brain metabolite levels at the same time. These studies may ultimately help to reveal what initiates memory decline and may, perhaps, even predict dementia risk.

The researchers believe that measuring such data over time will allow them to more accurately detect and describe changes in metabolism in the brain as a person progresses from healthy to mild cognitive impairment and to dementia.

The findings were published in the January issue of Neurobiology of Aging.

“We hope one day to use this technology to understand the earliest changes in brain chemistry that are associated with cognitive and behavioral symptoms that could represent new targets for treatment,” says Gwenn S. Smith, Ph.D., the Richman Family Professor of Alzheimer’s and Related Diseases, Department of Psychiatry and Behavioral Sciences at the Johns Hopkins University School of Medicine and director of the Division of Geriatric Psychiatry and Neuropsychiatry. “Right now, we don’t know the biological mechanism in the brain that initiates memory impairment, and we believe that using this technique we may eventually be able to understand the chemical changes in the brain that trigger this damage, and perhaps one day intervene to prevent it.”

The researchers say they detected a decrease in two particular chemical messengers, GABA and glutamate, in people who have mild cognitive impairment, compared with those who do not have it.

Previous studies by the researchers showed that other kinds of brain imaging, notably PET scans, uniquely could detect the neurotransmitters–the brain’s chemical messengers–serotonin and dopamine. Both of these chemicals are involved in mood, memory and cognitive decline. But, each chemical measured this way requires its own PET scan.

The technology used in the new study, magnetic resonance spectroscopy (MRS), is very similar to magnetic resonance imaging (MRI), which uses strong magnetic fields and radio waves to create and project images of tissues and organs. Whereas MRI primarily measures the brain’s water, MRS has been long used to identify chemical breakdown products, or metabolites, in an unknown substance based on unique, or “signature” peaks of the substances generated in response to certain vibrations. MRS uses a combination of a strong magnet and radio waves to stimulate molecules in the brain to perform distinct, tiny tumbling movements. Computer analysis then identifies the chemical metabolites depending on where the spikes appear on a scale that ranks the chemicals by how fast the signals appear from these tumbling movements. How tall and wide the spikes are on the scale determines how much of the chemical is in the targeted brain area.

When using common, clinical MRI machines, however, the researchers say, the spikes bleed into one another, and chemicals with similar structures can’t be distinguished from one another. The researchers started using a device with a more powerful magnet, known as 7-Tesla. The magnetic field strength of this machine is more than 100,000 times the strength of the magnetic field of the Earth.

“We are looking at extremely small concentrations of chemicals in the brain, with concentrations about 50,000 times lower than water–essentially the proverbial needles in a haystack,” says Georg Oeltzschner, Ph.D., postdoctoral fellow in the Russell H. Morgan Department of Radiology and Radiological Science at the Johns Hopkins University School of Medicine. “The very low signals and sensitive technology is why this technique has not been widely used to measure the signals of the chemicals we are interested in. With the strong magnet, we’re able to improve the signal and resolution decisively.”

“These different chemicals can be measured in a single scan, and complement the brain chemicals we can measure with the PET scan,” says Smith.

Expecting to see differences in the chemical composition of the brain in people with mild cognitive impairment compared with healthy people, the researchers recruited 13 people with mild cognitive impairment and 13 healthy controls. Seven of the 26 participants were women and the participants were an average age of 67.

To confirm that the participants had mild cognitive impairment, they had to score at least one-and-a-half standard deviations below the normal range on the California Verbal Learning Test or the Brief Visuospatial Memory Test, standard tests of memory. Using a PET scan to measure the amyloid protein plaques that appear early on in the brains of people with the disease, they confirmed that each participant with mild cognitive impairment had evidence of these protein plaques.

The researchers wanted to measure neurotransmitters and brain metabolites found in parts of the brain known to show changes in people with Alzheimer’s disease: the anterior cingulate cortex and the posterior cingulate cortex. Both places fall in the part of the brain responsible for thinking and mood in the center midline that divides the brain into right and left hemispheres, with one location near the front of the head and the other near the back. Each MRS scan for a specific brain region with the 7-Tesla magnet took approximately 5-10 minutes to get sufficient resolution and signal strength of the chemical components in each of the brain locations.

The researchers identified and compared levels of the neurotransmitters GABA and glutamate, the metabolite N-acetylaspartylglutamate, the antioxidant glutathione, and the markers of neuronal health N-acetylaspartate and myo-inositol, which at higher levels indicates brain inflammation.

The most striking finding, Smith says, was a 16 percent decrease of GABA in the brains of people who have mild cognitive impairment compared with healthy people, using the chemical creatine as reference to standardize metabolite levels from person to person. For example, in the region toward the front of the brain, the ratio of GABA to creatine was 0.42 in healthy people compared with 0.34 in people with mild cognitive impairment. They also found decreases of about 6 percent in glutamate in the brains of people with mild cognitive impairment.

“This pilot study shows that we can use MRS to measure individual metabolites in the brain, and we can detect changes in brain chemicals between healthy folks and people at risk for Alzheimer’s disease,” says Smith. “Now we can gear-up to do a larger study with more people to get more meaningful results.”

Oeltzschner said he also plans to apply newly developed measurement techniques capable of measuring GABA and other low-concentration metabolites on the more common MRI machines with 3.0 Tesla strength magnets. These new techniques may enable more places to do these kinds of measurements, as 7-Tesla machines are expensive and still relatively rare.

Source:

https://www.hopkinsmedicine.org/news/newsroom/news-releases/measuring-differences-in-brain-chemicals-in-people-with-mild-memory-problems

Tagged with:

About author

Related Articles