Lithium and Stroke Recovery: A Systematic Review and Meta-Analysis of Stroke Models in Rodents and Human Data.

BACKGROUND: Lithium has neuroprotective effects in animal models of stroke, but benefits in humans remain uncertain. This article aims to systematically review the available evidence of the neuroprotective and regenerative effects of lithium in animal models of stroke, as well as in observational and trial stroke studies in humans. METHODS: This systematic review and meta-analysis was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched Medline, Embase, and PsycINFO for preclinical and clinical studies published between January 2000 and September 2021. A random-effects meta-analysis was conducted from observational studies. RESULTS: From 1625 retrieved studies, 42 were included in the systematic review. Of those, we identified 36 rodent models of stroke using preinsult or postinsult treatment with lithium, and 6 studies were conducted in human samples, of which 4 could be meta-analyzed. The review of animal models was stratified according to the type of stroke and outcomes. Human data were subdivided into observational and intervention studies. Treatment of rodents with lithium was associated with smaller stroke volumes, decreased apoptosis, and improved poststroke function. In humans, exposure to lithium was associated with a lower risk of stroke among adults with bipolar disorder in 2 of 4 studies. Two small trials showed equivocal clinical benefits of lithium poststroke. CONCLUSIONS: Animal models of stroke show consistent biological and functional evidence of benefits associated with lithium treatment, whereas human evidence remains sparse and inconclusive. The potential role of lithium in poststroke recovery is yet to be adequately tested in humans.

Demographic and clinical characteristics of lithium-treated older adults with bipolar disorder.

OBJECTIVES: There is limited information on the characteristics of older adults with bipolar disorder (OABD) treated with lithium, along with safety concerns about its use by older adults. The aim of the present study is to describe the demographic and clinical characteristics of OABD receiving lithium therapy, using data from the Global Ageing & Geriatric Experiments in Bipolar Disorder (GAGE-BD). EXPERIMENTAL PROCEDURES: Cross-sectional analysis of the GAGE-BD dataset to determine differences and similarities between lithium users and non-users. We analysed data from 986 participants aged 50 years or older (mean age 63.5 years; 57.5% females) from 12 study sites. Two subgroups ('Lithium'; 'Non-lithium') were defined according to the current prescription of lithium. We compared several outcomes between these groups, controlling for age, gender, and study site. RESULTS: OABD treated with lithium had lower scores on depression rating scales and were less likely to be categorised as with moderate or severe depression. There was a lower proportion of lithium users than non-users among those with evidence of rapid cycling and non-bipolar psychiatric diagnoses. Assessment of global cognitive state and functionality indicated better performance among lithium users. The current use of antipsychotics was less frequent among lithium users, who also reported fewer cardiovascular comorbidities than non-users. CONCLUSION: We found several potentially relevant differences in the clinical profile of OABD treated with lithium compared with those treated with other mood stabilisers. However, the interpretation of the present results must take into account the methodological limitations inherent to the cross-sectional approach and data harmonisation.

Antipsychotics preserve telomere length in peripheral blood mononuclear cells after acute oxidative stress injury.

Antipsychotics may prolong or retain telomere length, affect mitochondrial function, and then affect the metabolism of nerve cells. To validate the hypothesis that antipsychotics can prolong telomere length after oxidative stress injury, leukocytes from healthy volunteers were extracted using Ficoll-Histopaque density gradient. The mononuclear cells layer was resuspended in cell culture medium. Oxidative stress was induced with hydrogen peroxide in cultured leukocytes. Four days later, leukocytes were treated with aripiprazole, haloperidol or clozapine for 7 days. Real-time PCR revealed that treatments with aripiprazole and haloperidol increased the telomere length by 23% and 20% in peripheral blood mononuclear cells after acute oxidative stress injury. These results suggest that haloperidol and aripiprazole can reduce the damage to telomeres induced by oxidative stress. The experiment procedure was approved by the Ethics Committee of Faculty of Medicine of the University of São Paulo (FMUSP/CAAE approval No. 52622616.8.0000.0065).

Mitochondrial dysfunction in Alzheimer's disease: Therapeutic implications of lithium.

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases, characterized by the accumulation of abnormal tau proteins within neurons and amyloid plaques in the brain parenchyma, which leads to progressive loss of neurons in the brain. While the detailed mechanism of the pathogenesis of AD is still unknown, evidence suggests that mitochondrial dysfunction likely plays a fundamental role in the pathogenesis of this disease. Due to the relevance of mitochondrial alterations in AD, recent works have suggested the therapeutic potential of mitochondrial-targeted lithium. Lithium has been shown to possess neuroprotective and neurotrophic properties that could also be related to the upregulation of mitochondrial function. In the current work, we perform a comprehensive investigation of the significance of mitochondrial dysfunction in AD and pharmacological treatment with lithium as imperative in this pathology, through a brief review of the major findings on the effects of lithium as a therapeutic approach targeting mitochondria in the context of AD.

Acute and chronic lithium treatment increases Wnt/ß-catenin transcripts in cortical and hippocampal tissue at therapeutic concentrations in mice.

Lithium activates Wnt/ß-catenin signaling leading to stabilization of free cytosolic ß-catenin. The aim of the present study is to evaluate the in vivo effect of acute and chronic lithium treatment on the expression of ß-catenin target genes, addressing its transcripts HIG2, Bcl-xL, Cyclin D1, c-myc, in cortical and hippocampal tissue from adult mice. Lithium doses were established to yield therapeutic working concentrations. In acute treatment, mice received a 300µL of a 350 mg/kg solution of LiCl by gavage, and were euthanized after 2 h, 6 h and 12 h. To determine the effect of chronic treatment, animals were continuously fed either with chow supplemented with 2 g/kg Li2CO3, or regular chow (controls), being euthanized after 30 days. All animals had access to drinking water and 0.9% saline ad libitum. After acute and chronic treatments samples of peripheral blood were obtained from the tail vein for each animal, and serum concentrations of lithium were determined. All transcripts were up-regulated in cortical and hippocampal tissues of lithium-treated mice, both under acute and chronic treatments. There was a positive correlation between serum lithium concentrations and the increment in the expression of all transcripts. This effect was observed in all time points of the acute treatment (i.e., 2, 6 and 12 hours) and also after 30 days. We conclude that Wnt/ß-catenin transcriptional response (HIG2, Bcl-xL, Cyclin D1 and c-myc) is up-regulated in the mouse brain in response to acute and chronic lithium treatment at therapeutic concentrations.

Long-term lithium treatment increases intracellular and extracellular brain-derived neurotrophic factor (BDNF) in cortical and hippocampal neurons at subtherapeutic concentrations.

OBJECTIVES: The putative neuroprotective effects of lithium treatment rely on the fact that it modulates several homeostatic mechanisms involved in the neurotrophic response, autophagy, oxidative stress, inflammation, and mitochondrial function. Lithium is a well-established therapeutic option for the acute and long-term management of bipolar disorder and major depression. The aim of this study was to evaluate the effects of subtherapeutic and therapeutic concentrations of chronic lithium treatment on brain-derived neurotrophic factor (BDNF) synthesis and secretion. METHODS: Primary cultures of cortical and hippocampal neurons were treated with different subtherapeutic (0.02 and 0.2 mM) and therapeutic (2 mM) concentrations of chronic lithium treatment in cortical and hippocampal cell culture. RESULTS: Lithium treatment increased the intracellular protein expression of cortical neurons (10% at 0.02 mM) and hippocampal neurons (28% and 14% at 0.02 mM and 0.2 mM, respectively). Extracellular BDNF of cortical neurons increased 30% and 428% at 0.02 and 0.2 mM, respectively and in hippocampal neurons increased 44% at 0.02 mM. CONCLUSION: The present study indicates that chronic, low-dose lithium treatment up-regulates BDNF production in primary neuronal cell culture.

Lithium, a Therapy for AD: Current Evidence from Clinical Trials of Neurodegenerative Disorders.

BACKGROUND: Preclinical studies have shown that lithium modifies pathological cascades implicated in certain neurodegenerative disorders, such as Alzheimer's disease (AD), Huntigton`s disease (HD), multiple system atrophy (MSA) and amyotrophic lateral sclerosis (ALS). A critical question is whether these pharmacodynamic properties of lithium translate into neurodegenerative diseases modifying effects in human subjects. METHODS: We reviewed all English controlled clinical trials published in PubMed, PsycINFO, Embase, SCOPUS, ISI-Web with the use of lithium for the treatment of neurodegenerative disorders between July 2004 and July 2014. RESULTS: Lithium showed evidence for positive effects on cognitive functions and biomarkers in amnestic mild cognitive impairment (aMCI, 1 study) and AD (2 studies), even with doses lower than those used for mood stabilisation. Studies of Li in HD, MSA and CSI did not show benefits of lithium. However, due to methodological limitations and small sample size, these studies may be inconclusive. Studies in ALS showed consistently negative results and presented evidence against the use of lithium for the treatment of this disease. CONCLUSION: In absence of disease modifying treatments for any neurodegenerative disorders, the fact that at least 3 studies supported the effect of lithium in aMCI/AD is noteworthy. Future studies should focus on defining the dose range necessary for neuroprotective effects to occur.

Lithium Distinctly Modulates the Secretion of Pro- and Anti- Inflammatory Interleukins in Co-Cultures of Neurons and Glial Cells at Therapeutic and Sub-Therapeutic Concentrations.

Lithium is associated with various effects on immune functions, some of which are still poorly understood. The roles of many cytokines have been characterized in a variety of neurodevelopmental processes including neurogenesis, neuronal and glial cell migration, proliferation, differentiation, synaptic maturation and synaptic pruning. This work aims to evaluate the effects of different doses of lithium (0.02; 0.2 and 2mM) on the secretion of cytokines in co-cultures of cortical and hippocampal neurons with glial cells. Our results indicate that chronic treatment with lithium chloride at subtherapeutic concentrations are able to modify the secretion of pro- and anti-inflammatory interleukins in co-cultures of cortical and hippocampal neurons with glial cells.

Anti-dementia medications: current prescriptions in clinical practice and new agents in progress.

Almost three decades after the publication of the first clinical studies with tacrine, the pharmacological treatment of Alzheimer's disease (AD) remains a challenge. Randomized clinical trials have yielded evidence of significant - although modest and transient - benefit from cholinergic replacement therapy for people diagnosed with AD, and disease modification with antidementia compounds is still an urgent, unmet need. The natural history of AD is very long, and its pharmacological treatment must acknowledge different needs according to the stage of the disease process. Cognitive and functional deterioration evolves gradually since the onset of clinical symptoms, which may be preceded by several years or perhaps decades of silent, presymptomatic neurodegeneration. Therefore, the pharmacological treatment of AD must ideally comprise both a symptomatic effect to preserve or improve cognition and a disease-modifying effect to tackle the progression of the pathological process. Primary prevention is the ultimate goal, should these strategies be delivered to patients with preclinical AD. In this article, we briefly address the pharmaceutical compounds that are currently used for the symptomatic treatment of AD and discuss the ongoing strategies designed to modify its natural course.

Leukocyte telomerase activity and antidepressant efficacy in bipolar disorder.

Telomeres are DNA-protein complexes that cap linear DNA strands, protecting DNA from damage. Recently, shorten telomeres length has been reported in bipolar disorder (BD) and depression. The enzyme telomerase regulates telomeres׳ length, which has been associated with cellular viability; however it is not clear how telomerase may be involved in the pathophysiology and therapeutics of BD. In the present study, leukocyte telomerase activity was assessed in 28 medication-free BD depressed individuals (DSM-IV-TR criteria) at baseline and after 6 weeks of lithium therapy (n=21) also matching with 23 healthy controls. There was no difference between telomerase activity in subjects with BD depression (before or after lithium) and controls. Improvement of depressive symptoms was negatively associated with telomerase activity after 6 weeks of lithium therapy. This is the first study describing telomerase activity in BD research. Overall, telomerase activity seems not directly involved in the pathophysiology of short-term BD. Lithium׳s antidepressant effects may involve regulation at telomerase activity. Further studies with larger samples and long-term illness are also warranted.

Alzheimer's disease.

Alzheimer's disease (AD) is a chronic neurodegenerative disease with well-defined pathophysiological mechanisms, mostly affecting medial temporal lobe and associative neocortical structures. Neuritic plaques and neurofibrillary tangles represent the pathological hallmarks of AD, and are respectively related to the accumulation of the amyloid-beta peptide (Aß) in brain tissues, and to cytoskeletal changes that arise from the hyperphosphorylation of microtubule-associated Tau protein in neurons. According to the amyloid hypothesis of AD, the overproduction of Aß is a consequence of the disruption of homeostatic processes that regulate the proteolytic cleavage of the amyloid precursor protein (APP). Genetic, age-related and environmental factors contribute to a metabolic shift favoring the amyloidogenic processing of APP in detriment of the physiological, secretory pathway. Aß peptides are generated by the successive cleavage of APP by beta-secretase (BACE-1) and gamma-secretase, which has been recently characterized as part of the presenilin complex. Among several beta-amyloid isoforms that bear subtle differences depending on the number of C-terminal amino acids, Aß (1-42) plays a pivotal role in the pathogenesis of AD. The neurotoxic potential of the Aß peptide results from its biochemical properties that favor aggregation into insoluble oligomers and protofibrils. These further originate fibrillary Aß species that accumulate into senile and neuritic plaques. These processes, along with a reduction of Aß clearance from the brain, leads to the extracellular accumulation of Aß, and the subsequent activation of neurotoxic cascades that ultimately lead to cytoskeletal changes, neuronal dysfunction and cellular death. Intracerebral amyloidosis develops in AD patients in an age-dependent manner, but recent evidence indicate that it may be observed in some subjects as early as in the third or fourth decades of life, with increasing magnitude in late middle age, and highest estimates in old age. According to recent propositions, three clinical phases of Alzheimer's disease may be defined: (i) pre-symptomatic (or pre-clinical) AD, which may last for several years or decades until the overproduction and accumulation of Aß in the brain reaches a critical level that triggers the amyloid cascade; (ii) pre-dementia phase of AD (compatible with the definition of progressive, amnestic mild cognitive impairment), in which early-stage pathology is present, ranging from mild neuronal dystrophy to early-stage Braak pathology, and may last for several years according to individual resilience and brain reserve; (iii) clinically defined dementia phase of AD, in which cognitive and functional impairment is severe enough to surmount the dementia threshold; at this stage there is significant accumulation of neuritic plaques and neurofibrillary tangles in affected brain areas, bearing relationship with the magnitude of global impairment. New technologies based on structural and functional neuroimaging, and on the biochemical analysis of cerebrospinal fluid may depict correlates of intracerebral amyloidosis in individuals with mild, pre-dementia symptoms. These methods are commonly referred to as AD-related biomarkers, and the combination of clinical and biological information yields good diagnostic accuracy to identify individuals at high risk of AD. In other words, the characterization of pathogenic Aß by means of biochemical analysis of biological fluids or by molecular neuroimaging are presented as diagnostic tools to help identify AD cases at the earliest stages of the disease process. The relevance of this early diagnosis of AD relies on the hypothesis that pharmacological interventions with disease-modifying compounds are more likely to produce clinically relevant benefits if started early enough in the continuum towards dementia. Therapies targeting the modification of amyloid-related cascades may be viewed as promising strategies to attenuate or even to prevent dementia. Therefore, the cumulative knowledge on the pathogenesis of AD derived from basic science models will hopefully be translated into clinical practice in the forthcoming years.

Does lithium prevent Alzheimer's disease?

Lithium salts have a well-established role in the treatment of major affective disorders. More recently, experimental and clinical studies have provided evidence that lithium may also exert neuroprotective effects. In animal and cell culture models, lithium has been shown to increase neuronal viability through a combination of mechanisms that includes the inhibition of apoptosis, regulation of autophagy, increased mitochondrial function, and synthesis of neurotrophic factors. In humans, lithium treatment has been associated with humoral and structural evidence of neuroprotection, such as increased expression of anti-apoptotic genes, inhibition of cellular oxidative stress, synthesis of brain-derived neurotrophic factor (BDNF), cortical thickening, increased grey matter density, and hippocampal enlargement. Recent studies addressing the inhibition of glycogen synthase kinase-3 beta (GSK3B) by lithium have further suggested the modification of biological cascades that pertain to the pathophysiology of Alzheimer's disease (AD). A recent placebo-controlled clinical trial in patients with amnestic mild cognitive impairment (MCI) showed that long-term lithium treatment may actually slow the progression of cognitive and functional deficits, and also attenuate Tau hyperphosphorylation in the MCI-AD continuum. Therefore, lithium treatment may yield disease-modifying effects in AD, both by the specific modification of its pathophysiology via inhibition of overactive GSK3B, and by the unspecific provision of neurotrophic and neuroprotective support. Although the clinical evidence available so far is promising, further experimentation and replication of the evidence in large scale clinical trials is still required to assess the benefit of lithium in the treatment or prevention of cognitive decline in the elderly.

Inhibition of phospholipase A2 in rat brain decreases the levels of total Tau protein.

The microtubule-associated protein Tau promotes the assembly and stability of microtubules in neuronal cells. Six Tau isoforms are expressed in adult human brain. All six isoforms become abnormally hyperphosphorylated and form neurofibrillary tangles in Alzheimer disease (AD) brains. In AD, reduced activity of phospholipase A(2) (PLA(2)), specifically of calcium-dependent cytosolic PLA(2) (cPLA(2)) and calcium-independent intracellular PLA(2) (iPLA(2)), was reported in the cerebral cortex and hippocampus, which positively correlated with the density of neurofibrillary tangles. We previously demonstrated that treatment of cultured neurons with a dual cPLA(2) and iPLA(2) inhibitor, methyl arachidonyl fluorophosphonate (MAFP), decreased total Tau levels and increased Tau phosphorylation at Ser(214) site. The aim of this study was to conduct a preliminary investigation into the effects of in vivo infusion of MAFP into rat brain on PLA(2) activity and total Tau levels in the postmortem frontal cortex and dorsal hippocampus. PLA(2) activity was measured by radioenzymatic assay and Tau levels were determined by Western blotting using the anti-Tau 6 isoforms antibody. MAFP significantly inhibited PLA(2) activity in the frontal cortex and hippocampus. The reactivity to the antibody revealed three Tau protein bands with apparent molecular weight of close to 40, 43 and 46 kDa in both brain areas. MAFP decreased the 46 kDa band intensity in the frontal cortex, and the 43 and 46 kDa band intensities in the hippocampus. The results indicate that in vivo PLA(2) inhibition in rat brain decreases the levels of total (nonphosphorylated plus phosphorylated) Tau protein and corroborate our previous in vitro findings.

Increased platelet GSK3B activity in patients with mild cognitive impairment and Alzheimer's disease.

The disruption of glycogen synthase kinase 3-beta (GSK3B) homeostasis has implications in the pathophysiology of neuropsychiatric disorders, namely Alzheimer's disease (AD). GSK3B activity is increased within the AD brain, favoring the hyperphosphorylation of microtubule-associated protein Tau and the formation of neurofibrillary tangles. Such abnormality has also been detected in leukocytes of patients with cognitive disorders. The aim of the present study was to determine the expression of total and phosphorylated GSK3B at protein level in platelets of older adults with varying degrees of cognitive impairment, and to compare GSK3B activity in patients with AD, mild cognitive impairment (MCI) and healthy controls. Sixty-nine older adults were included (24 patients with mild to moderate AD, 22 patients with amnestic MCI and 23 elderly controls). The expression of platelet GSK3B (total- and Ser-9 phosphorylated GSK3B) was determined by Western blot. GSK3B activity was indirectly assessed by means of the proportion between phospho-GSK3B to total GSK3B (GSK3B ratio), the former representing the inactive form of the enzyme. Ser-9 phosphorylated GSK3B was significantly reduced in patients with MCI and AD as compared to controls (p=0.04). Platelet GSK3B ratio was significantly decreased in patients with MCI and AD (p=0.04), and positively correlated with scores on memory tests (r=0.298, p=0.01). In conclusion, we corroborate previous evidence of increased GSK activity in peripheral tissues of patients with MCI and AD, and further propose that platelet GSK may be an alternative peripheral biomarker of this abnormality, provided samples are adequately handled in order to preclude platelet activation.

Collybistin and gephyrin are novel components of the eukaryotic translation initiation factor 3 complex.

BACKGROUND: Collybistin (CB), a neuron-specific guanine nucleotide exchange factor, has been implicated in targeting gephyrin-GABAA receptors clusters to inhibitory postsynaptic sites. However, little is known about additional CB partners and functions. FINDINGS: Here, we identified the p40 subunit of the eukaryotic translation initiation factor 3 (eIF3H) as a novel binding partner of CB, documenting the interaction in yeast, non-neuronal cell lines, and the brain. In addition, we demonstrated that gephyrin also interacts with eIF3H in non-neuronal cells and forms a complex with eIF3 in the brain. CONCLUSIONS: Together, our results suggest, for the first time, that CB and gephyrin associate with the translation initiation machinery, and lend further support to the previous evidence that gephyrin may act as a regulator of synaptic protein synthesis.

Inhibition of phospholipase A2 increases tau phosphorylation at Ser214 in embryonic rat hippocampal neurons.

BACKGROUND: Arachidonic acid is released from cellular membranes by the action of phospholipase A(2) (PLA(2)) and is implicated in microtubule-associated protein Tau phosphorylation. Tau hyperphosphorylation affects its ability to stabilize microtubules. OBJECTIVE: To determine the effect of PLA(2) inhibition on the phosphorylation state of Tau phosphoepitopes in primary cultures of hippocampal neurons. METHODS: 4 DIC neurons were incubated at different concentrations of methyl-arachidonylfluorophosphonate (MAFP), an irreversible inhibitor of cPLA(2) and iPLA(2). Changes on Tau phosphorylation were determined by Western blotting with a panel of anti-Tau antibodies (C-terminal, Ser199/202, Ser202/205, Ser396 and Ser214). RESULTS: The Ser214 site was hyperphosphorylated upon MAFP treatment. Significant differences were observed with 10 microM (p=0.01), 50 microM (p=0.01) and 100 microM (p=0.05) of MAFP. Less-intense changes were found in other phosphoepitopes. CONCLUSION: The present findings indicate that the phosphorylation of Ser214 is regulated by c- and/or iPLA(2), whereas other phosphoepitopes primarily regulated by GKS3b were not affected.