Monthly Archives: November 2014

Diagnostic for Early Biomarker of Cognitive Decline

Arterial spin labeling (ASL), a promising magnetic resonance imaging (MRI) technique that doesn’t require injection of a contrast agent, can detect signs of cognitive decline in the brain even before symptoms appear, say researchers from the University of Geneva in Switzerland.

Sven Haller, MD, and colleagues studied 48 healthy elderly participants and 65 people with mild cognitive impairment (MCI). The participants underwent brain MRI and a neuropsychological assessment, a common battery of tests used to determine cognitive ability. At clinical follow-up 18-months later, of the 148 healthy individuals, 75 remained stable, while 73 deteriorated cognitively.

Those who deteriorated had shown reduced perfusion at their baseline ASL MRI exams, particularly in the posterior cingulate cortex, an area in the middle of the brain that is associated with the default mode network, the neural network that is active when the brain is not concentrating on a specific task.

Declines in this network are seen in patients with mild cognitive impairment (MCI) and are more pronounced in those with Alzheimer’s disease. “There is a known close link between neural activity and brain perfusion in the posterior cingulate cortex. Less perfusion indicates decreased neural activity,” Dr. Haller said. “ASL MRI is simple to perform, doesn’t require special equipment and only adds a few minutes to the exam.”

The results suggest that the technique has the potential to serve as a biomarker in very early diagnosis of preclinical dementia. Early detection of cognitive decline is vital, as treatments for Alzheimer’s disease, the most common type of dementia, are most effective in this early phase.

Xekardaki A, Rodriguez C, Montandon ML, et al. Arterial Spin Labeling May Contribute to the Prediction of Cognitive Deterioration in Healthy Elderly Individuals. Radiology. 2014, Oct 7. 

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Two Foods Boost Cell Processes For Longevity

The protein known as Nrf2 plays a key role in cell health. When Nrf2 is exposed to threats, it oscillates faster and activates an increase in the cell’s defense mechanism, including raising the levels of antioxidant.  Paul Thornalley, from the University of Warwick (United Kingdom), and colleagues have observed that sulforaphane in broccoli, and quercetin in onions, are capable of increasing Nrf2 movement.

Observing a continual movement cycle of Nrf2, which sees the protein oscillate in and out of the cell nucleus once every 129 minutes, the team found that sulforaphane and  quercetin sped the cycle up to 80 minutes.  Writing that: “We discovered cytoplasmic refresh rate of Nrf2 is important in maintaining and regulating the transcriptional response and links stress challenge to increased cytoplasmic surveillance,” the study authors aim to develop new food supplements – superfoods that stimulate Nrf2 activity.

Xue M, Momiji H, Rabbani N, Barker G, Bretschneider T, Shmygol A, Rand D, Thornalley PJ.  “Frequency modulated translocational oscillations of Nrf2 mediate the ARE cytoprotective transcriptional response.” Antioxid Redox Signal. 2014 Sep 2.

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Physical Activity Keeps White Matter in Shape

White matter tracts enable communication between areas of the brain, but like the rest of the body, they decline with age. However, research suggests that staying active may help to preserve the integrity of these tracts. Agnieszka Burzynska, a postdoctoral researcher at the University of Illinois, and colleagues used accelerometers to track physical activity in 88 healthy but “low-fit” participants aged 60 to 78. Results showed that older adults who engaged more often in light physical activity had greater structural integrity in the white-matter tracts of the temporal lobes, which play a key role in memory, language, and the processing of visual and auditory information. Conversely, those who spent more time sitting had lower structural integrity in the white-matter tracts connecting the hippocampus. “This relationship between the integrity of tracts connecting the hippocampus and sedentariness is significant even when we control for age, gender and aerobic fitness,” said Burzynska. “It suggests that the physiological effect of sitting too much, even if you still exercise at the end of the day for half an hour, will have a detrimental effect on your brain.”

Burzynska AZ, Chaddock-Heyman L, Voss MW, et al. Physical activity and cardiorespiratory fitness are beneficial for white matter in low-fit older adults. PLoS One. 2014 Sep 17;9(9):e107413.  For more visit http://www.eurekalert.org/pub_releases/2014-09/uoia-slp091614.php

 

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