High intracellular calcium concentrations in transformed lymphoblasts from subjects with bipolar I disorder.
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.


METHODS
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.
Emamghoreishi
M
M
Section of Biochemical Psychiatry, Clarke Institute of Psychiatry, Toronto, Ont.
Schlichter
L
L
Li
P P
PP
Parikh
S
S
Sen
J
J
Kamble
A
A
Warsh
J J
JJ
D000328:Adult; D001714:Bipolar Disorder / Q000097:blood* / Q000378:metabolism / Q000503:physiopathology; D001792:Blood Platelets / Q000737:chemistry; D002118:Calcium / Q000032:analysis* / Q000502:physiology; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral; D003866:Depressive Disorder / Q000097:blood / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000737:chemistry*; D008297:Male; D013601:T-Lymphocytes / Q000737:chemistry
D002118:Calcium