[Sportschosun, Jang Jong-ho] A study has found that Alzheimer's disease (AD) may be predicted through a protein released during exercise.
A research team led by Professor Kang Seong-hoon of the Department of Neurology at Korea University Guro Hospital, including Professor Kang Seong-hoon of the Department of Neurology at Korea University Guro Hospital, Professor Jeong Young-hee of the Department of Neurology at Hallym University Pyeongchon Sacred Heart Hospital, Professor Lee Eun-seong of the Department of Nuclear Medicine at Korea University Guro Hospital, and Professor Kim Hyun-soo of the Department of Anatomy at Korea University College of Medicine, confirmed that irisin, a protein secreted by muscles during exercise, is closely linked to brain amyloid accumulation, a key pathology of AD.
AD is known to begin with amyloid buildup in the brain, which is the earliest pathological change. As nerve cell damage progresses, it leads to memory decline and dementia. Recent animal studies have suggested that irisin, a protein released from muscles during exercise, may promote the removal of amyloid from the brain. However, few studies have analyzed blood irisin levels and the extent of amyloid accumulation together in humans.
To address this, the research team conducted blood tests, amyloid PET scans, and neuropsychological tests on 100 older adults ranging from the preclinical stage of AD to the dementia stage. The participants were divided into four groups according to the stage of AD progression: an amyloid-negative cognitively normal group, an amyloid-positive asymptomatic group, an amyloid-positive mild cognitive impairment group, and an AD dementia group. The team then comprehensively analyzed the relationship between blood irisin levels, brain amyloid accumulation, and cognitive function.
The results showed that all three groups with amyloid accumulation had lower blood irisin levels than the group without amyloid buildup.
In particular, blood irisin levels began to decline significantly from the stage in which amyloid had accumulated in the brain but cognitive function remained normal, suggesting that irisin may reflect very early biological changes in AD.
Professor Kang Seong-hoon of the Department of Neurology at Korea University Guro Hospital said, "Current early diagnosis of AD mainly relies on tests such as amyloid PET or cerebrospinal fluid analysis, which are costly and have limited accessibility. This study is meaningful because it suggests the potential for irisin measurement in blood to develop into a blood-based biomarker that can help screen for AD risk at an early stage."
The study also found that higher blood irisin levels were associated with lower Centiloid values, which indicate the degree of brain amyloid accumulation. Furthermore, mediation analysis showed that a decrease in irisin was linked to increased amyloid accumulation in the brain, and that these changes could lead to cognitive decline. This suggests that irisin is an important biological link connecting the core pathology of AD and cognitive impairment.
Professor Kang said, "Through this study, we provided clinical evidence for the muscle-brain axis by linking blood biomarker analysis with amyloid PET imaging. We confirmed in humans that exercise-induced increases in irisin are closely connected not only to muscle health but also to the core pathology of AD. We expect that future development of blood-based biomarkers using irisin, as well as strategies to prevent dementia through exercise and improved muscle function, will be important outcomes of this research."
The findings were recently published in the Alzheimer's Association's international journal, Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring.
Jang Jong-ho, bellho@sportschosun.com
This article has been translated by GripLabs Mingo AI.
