A proton magnetic resonance spectroscopy study of the chronic lead effect on the Basal ganglion and frontal and occipital lobes in middle-age adults.
BACKGROUND
Lead is known to be a health hazard to the human brain and nervous system based on data from epidemiologic studies. However, few studies have examined the mechanism or biochemical changes caused by lead in the human brain, although recently some have used magnetic resonance spectroscopy (MRS) to test brain metabolism in vivo.


OBJECTIVE
In this study, we used 3-T MRS to investigate brain metabolism in workers chronically exposed to lead and matched nonexposed controls.


METHODS



METHODS
Twenty-two workers at a lead paint factory served as chronically exposed subjects of this study. These workers did not have any clinical syndromes. Eighteen age- and sex-matched nonexposed healthy volunteers served as controls. We measured blood and bone lead and used a 3-T MRS to measure their levels of brain N-acetyl aspartate (NAA), choline (Cho), and total creatine (tCr). A structural questionnaire was used to collect demographic, work, and health histories and information about their life habits.


RESULTS
All the MRS measures were lower in the lead-exposed group. Increased blood and bone lead levels correlated with declines in Cho:tCr ratios, especially in the occipital lobe, where changes in all gray, subcortical, and white matter were significant. Increases in blood and patella lead in every layer of the frontal lobe correlated with significant decreases in NAA:tCr ratios. One of the strongest regression coefficients was -0.023 (SE = 0.005, p < 0.001), which was found in the NAA:tCr ratio of frontal gray matter.


CONCLUSIONS
We conclude that chronic exposure to lead might upset brain metabolism, especially NAA:tCr and Cho:tCr ratios. Brain NAA and Cho are negatively correlated to blood and bone lead levels, suggesting that lead induces neuronal and axonal damage or loss. The most significant changes occurred in frontal and occipital lobes, areas in which previous neurobehavioral studies have shown memory and visual performance to be adversely affected by lead toxicity.
Hsieh
Tsyh-Jyi
TJ
Department of Medical Imaging, Kaohsiung Medical University Hospital, Kaohsiung City, Taiwan.
Chen
Yi-Chun
YC
Li
Chun-Wei
CW
Liu
Gin-Chang
GC
Chiu
Yu-Wen
YW
Chuang
Hung-Yi
HY
D000328:Adult; D001479:Basal Ganglia / Q000187:drug effects*; D004781:Environmental Exposure; D005260:Female; D005625:Frontal Lobe / Q000187:drug effects*; D006801:Humans; D007854:Lead / Q000633:toxicity*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D014874:Water Pollutants, Chemical; D007854:Lead