Am J Psychiatry 1997; 154:976-982
Copyright © 1997 by American Psychiatric Association
High intracellular calcium concentrations in transformed lymphoblasts from subjects with bipolar I disorder
M Emamghoreishi, L Schlichter, PP Li, S Parikh, J Sen, A Kamble and JJ Warsh
Section of Biochemical Psychiatry, Clarke Institute of Psychiatry, Toronto, Ont.
OBJECTIVE: Higher basal concentrations of intracellular calcium Ca2+ in
platelets and lymphocytes from subjects with bipolar affective disorder
than in unipolar depressed and healthy subjects implicate abnormal
intracellular Ca2+ signaling in bipolar disorder. The purpose of this study
was to clarify whether these intracellular Ca2+ abnormalities are trait
related. METHOD: Basal Ca2+ concentration was measured by using ratiometric
fluorescence assay with fura-2 for T lymphocytes and
Epstein-Barr-virus-immortalized B lymphoblasts from physically healthy
subjects with DSM-IV diagnoses of bipolar mood disorder (bipolar I, N = 28;
bipolar II, N = 11) or major depressive disorder (N = 14), mixed
psychiatric patients with non-mood disorders (N = 14), and health subjects
(N = 20). Phytohemagglutinin-stimulated (10 micrograms/ml) intracellular
Ca2+ levels were also determined in T lymphocytes. RESULTS: The basal Ca2+
concentration was significantly higher in the B lymphoblasts from patients
with bipolar I disorder, but not bipolar II disorder or major depression,
than in healthy subjects or psychiatric patients with nonmood disorders.
There was a significant interaction between gender and diagnosis in the
effect on basal Ca2+ levels in T lymphocytes. Contrasts of diagnoses within
gender revealed significantly higher basal Ca2+ concentrations in T
lymphocytes in male bipolar I patients, but not mean with bipolar II
disorder or major depression, than in healthy male comparison subjects.
Phytohemagglutinin-stimulated Ca2+ concentrations did not differ among
groups, but the percent differences from basal Ca2+ levels were lower in
bipolar I and depressed patients than in healthy subjects. CONCLUSIONS:
These findings support the occurrence of abnormal calcium homeostasis in
bipolar disorder and suggest that trait-dependent factors account, at least
partly, for the higher basal lymphocyte Ca2+ concentration in bipolar I
subjects.
