Author
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FU, XUEYAN - Jean Mayer Human Nutrition Research Center On Aging At Tufts University |
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DOLNIKOWSKI, GREGORY - Jean Mayer Human Nutrition Research Center On Aging At Tufts University |
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PATTERSON, WILLIAM - Tufts University |
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DAWSON-HUGHES, BESS - Jean Mayer Human Nutrition Research Center On Aging At Tufts University |
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ZHENG, TONG - Jean Mayer Human Nutrition Research Center On Aging At Tufts University |
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MORRIS, MARTHA - Rush University |
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HOLLAND, THOMAS - Rush University |
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BOOTH, SARAH - Jean Mayer Human Nutrition Research Center On Aging At Tufts University |
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Submitted to: Current Developments in Nutrition
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/17/2019 Publication Date: 6/21/2019 Citation: Fu, X., Dolnikowski, G.G., Patterson, W.B., Dawson-Hughes, B., Zheng, T., Morris, M.C., Holland, T.M., Booth, S.L. 2019. Determination of vitamin D and its metabolites in human brain using an ultra pressure LC-tandem mass spectra method. Current Developments in Nutrition. 3(7):nzz074. https://doi.org/10.1093/cdn/nzz074. DOI: https://doi.org/10.1093/cdn/nzz074 Interpretive Summary: Low blood levels of vitamin D have been associated with cognitive impairment. However, it is unclear if blood levels of vitamin D are a valid indicator of the levels of vitamin D in the human brain. The objective of this study was to develop and validate a method to quantify vitamin D and its metabolites in the human brain. The mass spectrometry method was initially developed using pig brain samples, then it was validated using a whole human brain obtained from a tissue donor. Using the method, we were able to measure the levels of the three vitamin D forms in seven brain regions (the prefrontal cortex, middle frontal cortex, middle temporal cortex, cerebellum, corpus callosum, medulla, and pons of the human brain). To the best of our knowledge, is the first study to quantify the amount of different vitamin D forms in human brain. This validated method can be applied to post-mortem studies to obtain accurate information about the presence and amount of vitamin D forms in human brain, and their relation to neurodegenerative diseases. Technical Abstract: Background: Low serum total 25-hydroxyvitamin D3 [25(OH)D3] concentrations have been associated with cognitive impairment. However, it is unclear if serum 25(OH)D3 concentrations are a valid indicator of the concentrations of vitamin D and its metabolites in the human brain. Objective: To develop and validate a method to quantify vitamin D3, 25(OH)D3, and 1,25(OH)2D3 in the human brain. Methods: The assay developments were performed using porcine brains. Liquid extraction was used in homogenized samples (about 0.1 g each) prior to analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization following derivatization with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD). This method was then applied to the determination of vitamin D and its metabolites in a whole human brain obtained from the National Development and Research Institutes. Results: The method showed good linearity of vitamin D3, 25(OH)D3, and 1,25(OH)2D3 over the physiological range (R^2=0.9995, 0.9968 and 0.9970, respectively). The lowest detection limit for vitamin D3, 25(OH)D3, and 1,25(OH)2D3 in porcine brain was 25, 50 and 25 pg/g, respectively. The method was successfully applied to the determination of vitamin D3 and its metabolites in the prefrontal cortex, middle frontal cortex, middle temporal cortex, cerebellum, corpus callosum, medulla and pons of the human brain. All analyzed human brain regions contained 25(OH)D3, with corpus callosum containing 334 pg/g compared to 158 pg/g in cerebellum. 1,25(OH)2D3 was only detected in prefrontal and middle frontal cortex at a very low level. There was no vitamin D3 detected in any examined areas of this single human brain. Conclusions: To the best of our knowledge, this study is the first report of the measurement of concentrations of vitamin D metabolites in human brain. This validated method can be applied to post-mortem studies to obtain accurate information about the presence and role of vitamin D and metabolites in human brain and neurodegenerative diseases. |
