Lithium Effects on Brain and Blood

Abstract

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.

Similar articles

• Lithium up-regulates the cytoprotective protein Bcl-2 in the CNS in vivo: a role for neurotrophic and neuroprotective effects in manic depressive illness.

• Manji HK, Moore GJ, Chen G.

• J Clin Psychiatry. 2000;61 Suppl 9:82-96.

• PMID: 10826666 Review.

• Molecular actions and therapeutic potential of lithium in preclinical and clinical studies of CNS disorders.

• Chiu CT, Chuang DM.

• Pharmacol Ther. 2010 Nov;128(2):281-304. doi: 10.1016/j.pharmthera.2010.07.006. Epub 2010 Aug 10.

• PMID: 20705090 Free PMC article. Review.

• Lithium neuroprotection: molecular mechanisms and clinical implications.

• Rowe MK, Chuang DM.

• Expert Rev Mol Med. 2004 Oct 18;6(21):1-18. doi: 10.1017/S1462399404008385.

• PMID: 15488156 Review.

• [Neuroprotective actions of lithium].

• Hashimoto R, Fujimaki K, Jeong MR, Senatorov VV, Christ L, Leeds P, Chuang DM, Takeda M.

• Seishin Shinkeigaku Zasshi. 2003;105(1):81-6.

• PMID: 12701214 Review. Japanese.

• The antiapoptotic actions of mood stabilizers: molecular mechanisms and therapeutic potentials.

• Chuang DM.

• Ann N Y Acad Sci. 2005 Aug;1053:195-204. doi: 10.1196/annals.1344.018.

• PMID: 16179524 Review.