TY - JOUR

T1 - Quantitative measurement of [Na+] and [K+] in postmortem human brain tissue indicates disturbances in subjects with Alzheimer's Disease and dementia with Lewy bodies

AU - Graham, Stewart F.

AU - Nasarauddin, Muhammad Bin

AU - Carey, Manus

AU - McGuinness, Bernadette

AU - Holscher, Christian

AU - Kehoe, Patrick G.

AU - Love, Seth

AU - Passmore, Anthony P.

AU - Elliott, Christopher T.

AU - Meharg, Andrew

AU - Green, Brian D.

PY - 2015

Y1 - 2015

N2 - Alzheimer's disease (AD) is associated with significant disturbances in the homeostasis of Na+ and K+ ions as well as reduced levels of Na+/K+ ATPase in the brain. This study used ICP-MS to accurately quantify Na+ and K+ concentrations in human postmortem brain tissue. We analyzed parietal cortex (Brodmann area 7) from 28 cognitively normal age-matched controls, 15 cases of moderate AD, 30 severe AD, and 15 dementia with Lewy bodies (DLB). Associations were investigated between [Na+] and [K+] and a number of variables including diagnosis, age, gender, Braak tangle stage, amyloid-β (Aβ) plaque load, tau load, frontal tissue pH, and APOE genotype. Brains from patients with severe AD had significantly higher (26%; p < 0.001) [Na+] (mean 65.43 ± standard error 2.91 mmol/kg) than controls, but the concentration was not significantly altered in moderate AD or DLB. [Na+] correlated positively with Braak stage (r = 0.45; p < 0.0001), indicating association with disease severity. [K+] in tissue was 10% lower (p < 0.05) in moderate AD than controls. However, [K+] in severe AD and DLB (40.97 ± 1.31 mmol/kg) was not significantly different from controls. There was a significant positive correlation between [K+] and Aβ plaque load (r = 0.46; p = 0.035), and frontal tissue pH (r = 0.35; p = 0.008). [Na+] was not associated with [K+] across the groups, and neither ion was associated with tau load or APOE genotype. We have demonstrated disturbances of both [Na+] and [K+] in relation to the severity of AD and markers of AD pathology, although it is possible that these relate to late-stage secondary manifestations of the disease pathology.

AB - Alzheimer's disease (AD) is associated with significant disturbances in the homeostasis of Na+ and K+ ions as well as reduced levels of Na+/K+ ATPase in the brain. This study used ICP-MS to accurately quantify Na+ and K+ concentrations in human postmortem brain tissue. We analyzed parietal cortex (Brodmann area 7) from 28 cognitively normal age-matched controls, 15 cases of moderate AD, 30 severe AD, and 15 dementia with Lewy bodies (DLB). Associations were investigated between [Na+] and [K+] and a number of variables including diagnosis, age, gender, Braak tangle stage, amyloid-β (Aβ) plaque load, tau load, frontal tissue pH, and APOE genotype. Brains from patients with severe AD had significantly higher (26%; p < 0.001) [Na+] (mean 65.43 ± standard error 2.91 mmol/kg) than controls, but the concentration was not significantly altered in moderate AD or DLB. [Na+] correlated positively with Braak stage (r = 0.45; p < 0.0001), indicating association with disease severity. [K+] in tissue was 10% lower (p < 0.05) in moderate AD than controls. However, [K+] in severe AD and DLB (40.97 ± 1.31 mmol/kg) was not significantly different from controls. There was a significant positive correlation between [K+] and Aβ plaque load (r = 0.46; p = 0.035), and frontal tissue pH (r = 0.35; p = 0.008). [Na+] was not associated with [K+] across the groups, and neither ion was associated with tau load or APOE genotype. We have demonstrated disturbances of both [Na+] and [K+] in relation to the severity of AD and markers of AD pathology, although it is possible that these relate to late-stage secondary manifestations of the disease pathology.

KW - Alzheimer's disease

KW - dementia with Lewy bodies

KW - human brain

KW - ICP-MS

KW - potassium

KW - sodium

U2 - 10.3233/JAD-141869

DO - 10.3233/JAD-141869

M3 - Journal article

C2 - 25362038

VL - 44

SP - 851

EP - 857

JO - Journal of Alzheimer's Disease

JF - Journal of Alzheimer's Disease

SN - 1387-2877

IS - 3

ER -