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Influence of manganese exposure on cognitive function, plasma APP and Aβ levels in older men
Jie Zhang1, Yiping Yang2, Xiaobo Yang3
1Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, Guangxi, China.
Background:
Elevated manganese (Mn) exposure impairs cognition in adults and children, but the association between Mn and cognitive function in elderly people is unclear. Previous studies have linked Mn neurotoxicity in AD to Aβ-dependent mechanisms. However, the association between Mn and plasma APP and Aβ in the general elderly population remains unknown. This study aimed to investigate the association between Mn exposure and cognitive function, plasma APP and plasma Aβ in older adults.
Methods:
Cognitive abilities in 375 men aged 60 and older in Guangxi, China were assessed using the Mini-Mental State Examination (MMSE) and cognitive impairment were identified using education-stratified cut-off points of MMSE scores. Urinary Mn levels and plasma APP, and Aβ levels were measured using ICP-MS and ELISA, respectively.
Results:
A total of 109 (29.07 %) older men were identified as having cognitive impairment. The median urinary Mn level was 0.22 μg/g creatinine. Urinary Mn levels were negatively correlated with MMSE scores (β = -1.35, 95 % CI: -2.65 to -0.06; p = 0.041). In addition, higher concentrations of urinary manganese were associated with a greater risk of cognitive impairment (OR = 2.03, 95 % CI: 1.14-3.59; comparing the highest and lowest manganese; p = 0.025). Moreover, plasma APP levels were inversely associated with urinary Mn levels (r = -0.123, p = 0.020), and positively associated with MMSE scores (r = 0.158, p = 0.002). Surprisingly, no correlations were observed between plasma Aβ42, Aβ40, Aβ40/Aβ42, or Aβ42/Aβ40 and urinary Mn levels and MMSE scores.
Conclusion:
These results suggested that Mn exposure is negatively associated with older men's cognition and plasma APP levels, but not plasma Aβ levels.
Insights
Elevated manganese (Mn) exposure is linked to cognitive decline and lower plasma amyloid precursor protein (APP) levels in older men. This study highlights potential risks of manganese on cognitive health in aging populations.
Area of Science:
- Environmental Health
- Neuroscience
- Gerontology
Background:
- Manganese (Mn) exposure is known to impair cognition, but its effects on the elderly are not well understood.
- Previous research suggests Mn neurotoxicity in Alzheimer's disease (AD) involves amyloid-beta (Aβ) pathways.
- The association between Mn and plasma APP/Aβ in the general elderly population requires investigation.
Purpose of the Study:
- To examine the relationship between manganese exposure and cognitive function in older adults.
- To investigate the association between manganese exposure and plasma amyloid precursor protein (APP) and amyloid-beta (Aβ) levels in the elderly.
Main Methods:
- Cognitive function was assessed in 375 older men (≥60 years) using the Mini-Mental State Examination (MMSE).
- Urinary Mn levels and plasma APP and Aβ levels were measured using ICP-MS and ELISA.
- Cognitive impairment was identified using education-stratified MMSE score cut-offs.
Main Results:
- Higher urinary Mn levels were negatively correlated with MMSE scores (β = -1.35, p=0.041) and associated with increased risk of cognitive impairment (OR = 2.03, p=0.025).
- Plasma APP levels were inversely associated with urinary Mn (r = -0.123, p=0.020) and positively associated with MMSE scores (r = 0.158, p=0.002).
- No significant correlations were found between urinary Mn or MMSE scores and plasma Aβ42, Aβ40, or their ratios.
Conclusions:
- Manganese exposure is negatively associated with cognitive function in older men.
- Higher manganese exposure correlates with lower plasma APP levels.
- Manganese exposure was not associated with plasma Aβ levels in this elderly cohort.
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