TY - JOUR
T1 - Testing competing path models linking the biochemical variables in red blood cells from Li+ -treated bipolar patients
AU - Williams, Nicole
AU - Layden, Brian T.
AU - Suhy, Joyce
AU - Metreger, Tabitha
AU - Foley, Kathleen
AU - Abukhdeir, Abde M.
AU - Borge, George
AU - Crayton, John
AU - Bryant, Fred B.
AU - Mota de Freitas, Duarte
PY - 2003/10
Y1 - 2003/10
N2 - Objectives: Red blood cells (RBCs) from Li+-treated bipolar patients have shown abnormalities in intracellular Li+ concentration ([Li+]i), Na+/Li+ exchange rates, and membrane phospholipid levels. Based on Li+-loaded RBC studies, we hypothesized that Li+-treated bipolar patients also have varied intracellular free Mg2+ concentrations ([Mg2+]f) as compared with normotensive patients. We addressed how these experimentally determined values are intercorrelated. Assuming that Li+ treatment alters these biochemical parameters, we provide hypothetical pathways based upon structural equation modeling statistics. Methods: In RBCs from 30 Li+-treated bipolar patients, we determined [Li+]i, serum [Li+] ([Li+]c), Na+/Li+ exchange parameters, membrane phospholipid levels, [Mg2+]f, and Li+ membrane binding affinities. Comprehensive statistical analyses assessed correlations among the biochemical data. We used path analysis statistics to propose potential pathways in which the data were correlated. Results: We found significant correlations within the three Na+/Li+ exchange parameters and percentage composition of the membrane phospholipids. Additional correlations existed between [Mg2+]f and Vstd, Km, or phospholipid composition, between [Li+]i and percentage of phosphatidylcholine, and between percentage of phosphatidylserine and Km. Based on these findings, we hypothesized and statistically determined the most probable pathway through which these parameters were intercorrelated. Conclusions: Significant correlations existed between the biochemical parameters that describe the cell membrane abnormality and the Li+/Mg2+ competition hypotheses. Using path analysis statistics, we identified a biochemical pathway by which Li+ may assert its cellular effects. This study serves as an illustrative example how path analysis is a Valuable tool in determining the direction of a certain biochemical pathway.
AB - Objectives: Red blood cells (RBCs) from Li+-treated bipolar patients have shown abnormalities in intracellular Li+ concentration ([Li+]i), Na+/Li+ exchange rates, and membrane phospholipid levels. Based on Li+-loaded RBC studies, we hypothesized that Li+-treated bipolar patients also have varied intracellular free Mg2+ concentrations ([Mg2+]f) as compared with normotensive patients. We addressed how these experimentally determined values are intercorrelated. Assuming that Li+ treatment alters these biochemical parameters, we provide hypothetical pathways based upon structural equation modeling statistics. Methods: In RBCs from 30 Li+-treated bipolar patients, we determined [Li+]i, serum [Li+] ([Li+]c), Na+/Li+ exchange parameters, membrane phospholipid levels, [Mg2+]f, and Li+ membrane binding affinities. Comprehensive statistical analyses assessed correlations among the biochemical data. We used path analysis statistics to propose potential pathways in which the data were correlated. Results: We found significant correlations within the three Na+/Li+ exchange parameters and percentage composition of the membrane phospholipids. Additional correlations existed between [Mg2+]f and Vstd, Km, or phospholipid composition, between [Li+]i and percentage of phosphatidylcholine, and between percentage of phosphatidylserine and Km. Based on these findings, we hypothesized and statistically determined the most probable pathway through which these parameters were intercorrelated. Conclusions: Significant correlations existed between the biochemical parameters that describe the cell membrane abnormality and the Li+/Mg2+ competition hypotheses. Using path analysis statistics, we identified a biochemical pathway by which Li+ may assert its cellular effects. This study serves as an illustrative example how path analysis is a Valuable tool in determining the direction of a certain biochemical pathway.
KW - Bipolar disorder
KW - Li transport
KW - Lithium
KW - Path analysis statistics
KW - Red blood cells
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U2 - 10.1034/j.1399-5618.2003.00054.x
DO - 10.1034/j.1399-5618.2003.00054.x
M3 - Article
C2 - 14525552
AN - SCOPUS:0242300765
SN - 1398-5647
VL - 5
SP - 320
EP - 329
JO - Bipolar Disorders
JF - Bipolar Disorders
IS - 5
ER -