Anti-suppressor cell effects of lithium in vitro and in vivo

Review of lithium effects on brain and blood

Clinicians have long used lithium to treat manic depression. They have also observed that lithium causes granulocytosis and lymphopenia while it enhances immunological activities of monocytes and lymphocytes. In fact, clinicians have long used lithium to treat granulocytopenia resulting from radiation and chemotherapy, to boost immunoglobulins after vaccination, and to enhance natural killer activity. Recent studies revealed a mechanism that ties together these disparate effects of lithium. Lithium acts through multiple pathways to inhibit glycogen synthetase kinase-3beta (GSK3 beta). This enzyme phosphorylates and inhibits nuclear factors that turn on cell growth and protection programs, including the nuclear factor of activated T cells (NFAT) and WNT/beta-catenin. In animals, lithium upregulates neurotrophins, including brain-derived neurotrophic factor (BDNF), nerve growth factor, neurotrophin-3 (NT3), as well as receptors to these growth factors in brain. Lithium also stimulates proliferation of stem cells, including bone marrow and neural stem cells in the subventricular zone, striatum, and forebrain. The stimulation of endogenous neural stem cells may explain why lithium increases brain cell density and volume in patients with bipolar disorders. Lithium also increases brain concentrations of the neuronal markers n-acetyl-aspartate and myoinositol. Lithium also remarkably protects neurons against glutamate, seizures, and apoptosis due to a wide variety of neurotoxins. The effective dose range for lithium is 0.6-1.0 mM in serum and >1.5 mM may be toxic. Serum lithium levels of 1.5-2.0 mM may have mild and reversible toxic effects on kidney, liver, heart, and glands. Serum levels of >2 mM may be associated with neurological symptoms, including cerebellar dysfunction. Prolonged lithium intoxication >2 mM can cause permanent brain damage. Lithium has low mutagenic and carcinogenic risk. Lithium is still the most effective therapy for depression. It "cures" a third of the patients with manic depression, improves the lives of about a third, and is ineffective in about a third. Recent studies suggest that some anticonvulsants (i.e., valproate, carbamapazine, and lamotrigene) may be useful in patients that do not respond to lithium. Lithium has been reported to be beneficial in animal models of brain injury, stroke, Alzheimer's, Huntington's, and Parkinson's diseases, amyotrophic lateral sclerosis (ALS), spinal cord injury, and other conditions. Clinical trials assessing the effects of lithium are under way. A recent clinical trial suggests that lithium stops the progression of ALS.

Protective effect of lithium on the stress-induced depression of cell-mediated immunity in mice

The effect of lithium chloride (LiCl) administration on the stress-induced depression of cell-mediated immunity was studied in mice. Two models of stress-induced depression of immunity were used: (1) keeping the animals at a temperature of 4 degrees C twice for 24 h at a 24-h interval, and (2) keeping them in the dark for 96 h. Both kinds of stress significantly decreased the reactivity of cell donors in the graft-versus-host (GVH) reaction and recipients in the host-versus-graft (HVG) reaction. Treatment with LiCl of the cell donors in GVH reaction or the recipients in HVG reaction daily for three weeks before stress application completely abolished the immunosuppressive effect of "cooling" stress, but not "darkness" stress. The LiCl is thus shown as a potential immunomodulator protecting mice from some forms of the stress-induced depression of cell-mediated immunity.

Lithium-associated thyrotoxicosis

Primary hypothyroidism developed in a 57-year-old woman treated for eight years with lithium carbonate for manic-depressive illness, and nine months later she became thyrotoxic. Although autoimmune disease appeared to be responsible, lithium was suspected to play a contributory role in both phases of her illness. This is the first reported case of hyperthyroidism following hypothyroidism in a lithium-treated patient. The 24 reported cases of lithium-associated thyrotoxicosis and the possible mechanisms that may explain this poorly understood phenomenon are also reviewed.

A controlled study of cellular immune function in affective disorders before and during somatic therapy

Lymphocyte blastogenesis induced by lectins (PHA, Con A, and PWM) was assessed in 27 drug-free patients with unipolar (n = 21) or bipolar (n = 5) depression and 13 normal controls. Fifteen patients were restudied after clinical remission. Symptomatic patients did not differ from controls nor did endogenous and nonendogenous depressions differ in their lymphocyte blastogenesis response to any of the three lectins. However, a significant reduction in lymphocyte blastogenesis with both PHA and Con A stimulation was found following somatic treatment. Cellular immune function appears to be normal in depressed patients, although the somatic therapies are associated with a reduction in this function.

Circulating T-cell subpopulations in lithium-associated granulocytosis

Granulocytosis is a common feature in patients undergoing lithium therapy. With increasing evidence that T lymphocytes play a role in the control of granulopoiesis, we have investigated the effect of lithium administration on circulating levels of T helper and T suppressor cells, as identified by monoclonal antibodies, to determine whether lithium-induced granulocytosis is mediated through changes in peripheral blood T cell subsets. Lithium carbonate was administered to 10 subjects over a 2 week period. Differential leucocyte counts and T, B, T helper and T suppressor lymphocyte enumerations were performed prior to administration of lithium (Day 1) and on 2 occasions (Day 7 and 14) during ingestion of the drug. Ten healthy control subjects were similarly investigated. Small, but significant elevation (p less than 0.05) in neutrophil counts at 7 and 14 days were observed in subjects taking lithium, serum lithium levels at these times were 0.56 +/- 0.27 and 0.68 +/- 0.17 mmol/l, respectively; lymphocyte and monocyte levels were unaffected. The percentages and absolute numbers of circulating T, B, T helper and T suppressor lymphocytes were not significantly altered (p greater than 0.05) during lithium administration and did not differ significantly (p greater than 0.05) from those recorded for the control group. We were thus unable to demonstrate that short-term lithium administration induced changes in the circulating levels of T helper (OKT4+) or T suppressor (OKT8+) cells.

[Humoral autoimmune phenomena during long-term lithium treatment with special reference to thyroid autoantibodies]

In a retrospective study, 58 outpatients under long-term therapy with lithium were examined with regard to humoral autoantibodies. Fifty-five schizophrenic outpatients under neuroleptic treatment served as controls. We examined antithyroidal antibodies (TAK, MAK), smooth muscle antibodies (SMA), antimitochondrial antibodies (AMA), and antinuclear antibodies (ANA). In the lithium group there was a significant higher prevalence of antithyroidal antibodies (33%) as compared to the control group (9%). Ten patients out of 19 patients with antithyroidal antibodies showed MAK as well as TAK; moreover we found a characteristic pattern: MAK greater than or equal to TAK. All lithium-treated patients were euthyroid. Five patients out of the group with antithyroidal antibodies had goiter, three showed temporarily elevated serum concentrations of basal thyroid-stimulating hormone (TSH). We did not find such elevated levels of TSH in the group of eight patients with goiter but without antithyroidal antibodies. There was neither a correlation between the examined parameters and the lithium serum concentration nor the additional psychotropic medication. Our results indicate a significant higher prevalence of antithyroidal antibodies under long-term therapy with lithium as compared to a psychiatric control group. We do not consider these autoimmune phenomena as relevant pathogenetic factors.