Potential mechanisms involved in the prevention of neurodegenerative diseases by lithium

Round-window delivery of lithium chloride regenerates cochlear synapses damaged by noise-induced excitotoxic trauma via inhibition of the NMDA receptor in the rat

Noise exposure can destroy the synaptic connections between hair cells and auditory nerve fibers without damaging the hair cells, and this synaptic loss could contribute to difficult hearing in noisy environments. In this study, we investigated whether delivering lithium chloride to the round-window can regenerate synaptic loss of cochlea after acoustic overexposure. Our rat animal model of noise-induced cochlear synaptopathy caused about 50% loss of synapses in the cochlear basal region without damaging hair cells. We locally delivered a single treatment of poloxamer 407 (vehicle) containing lithium chloride (either 1 mM or 2 mM) to the round-window niche 24 hours after noise exposure. Controls included animals exposed to noise who received only the vehicle. Auditory brainstem responses were measured 3 days, 1 week, and 2 weeks post-exposure treatment, and cochleas were harvested 1 week and 2 weeks post-exposure treatment for histological analysis. As documented by confocal microscopy of immunostained ribbon synapses, local delivery of 2 mM lithium chloride produced synaptic regeneration coupled with corresponding functional recovery, as seen in the suprathreshold amplitude of auditory brainstem response wave 1. Western blot analyses revealed that 2 mM lithium chloride suppressed N-methyl-D-aspartate (NMDA) receptor expression 7 days after noise-exposure. Thus, round-window delivery of lithium chloride using poloxamer 407 reduces cochlear synaptic loss after acoustic overexposure by inhibiting NMDA receptor activity in rat model.

Is lithium neuroprotective? An updated mechanistic illustrated review

Neurodegeneration is a pathological process characterized by progressive neuronal impairment, dysfunction, and loss due to mitochondrial dysfunction, oxidative stress, inflammation, and apoptosis. Many studies have shown that lithium protects against neurodegeneration. Herein, we summarize recent clinical and laboratory studies on the neuroprotective effects of lithium against neurodegeneration and its potential to modulate mitochondrial dysfunction, oxidative stress, inflammation, and apoptosis. Recent findings indicate that lithium regulates critical intracellular pathways such as phosphatidylinositol-3 (PI3)/protein kinase B (Akt)/glycogen synthase kinase-3 (GSK3β) and PI3/Akt/response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF). We queried PubMed, Web of Science, Scopus, Elsevier, and other related databases using search terms related to lithium and its neuroprotective effect in various neurodegenerative diseases and events from January 2000 to May 2022. We reviewed the major findings and mechanisms proposed for the effects of lithium. Lithium's neuroprotective potential against neural cell degeneration is mediated by inducing anti-inflammatory factors, antioxidant enzymes, and free radical scavengers to prevent mitochondrial dysfunction. Lithium effects are regulated by two essential pathways: PI3/Akt/GSK3β and PI3/Akt/CREB/BDNF. Lithium acts as a neuroprotective agent against neurodegeneration by preventing inflammation, oxidative stress, apoptosis, and mitochondrial dysfunction using PI3/Akt/GSK3β and PI3/Akt/CREB/BDNF signaling pathways.

The Impact of Lithium on Brain Function in Bipolar Disorder: An Updated Review of Functional Magnetic Resonance Imaging Studies

Lithium remains a gold standard treatment for bipolar disorder (BD), and functional magnetic resonance imaging (fMRI) studies have contributed to clarifying its impact on neural circuitries in affected individuals. However, the specific neurobiological mechanisms through which lithium exerts its effects on brain function are not fully understood. In this review, we aimed to summarize the results of recent fMRI studies evaluating the impact of lithium on brain functional activity and connectivity in patients diagnosed with BD. We performed a literature search of available sources found in the PubMed database reported in English since 2016, when the last available review on this topic was published. Five fMRI studies in resting-state condition and six studies performed during the execution of emotional tasks met the inclusion criteria. Overall, the available evidence supports normalizing effects of lithium on brain activity and connectivity. Most of these studies reported a normalization in prefrontal regions and interconnected areas involved in emotion regulation and processing, regardless of the task employed. Importantly, lithium treatment showed distinct patterns of activity/connectivity changes compared with other treatments. Finally, lithium modulation of neural circuitries was found to be associated with clinical improvement in BD. These results are consistent with the hypothesis that selective abnormalities in neural circuitries supporting emotion processing and regulation improve during lithium treatment in BD. However, the heterogeneity of the examined studies regarding study design, sample selection, and analysis methods might limit the generalizability of the findings and lead to difficulties in comparing the results. Therefore, in future studies, larger cohorts and homogeneous experimental tasks are needed to further corroborate these findings.

Hormonal and biochemical changes in female Proechimys guyannensis, an animal model of resistance to pilocarpine-induced status epilepticus

The Amazon rodent Proechimys guyannensis is widely studied for hosting various pathogens, though rarely getting sick. Previous studies on male Proechimys have revealed an endogenous resistance to epilepsy. Here, we assess in female Proechimys, whether sex hormones and biochemical aspects can interfere with the induction of status epilepticus (SE). The lithium-pilocarpine ramp-up protocol was used to induce SE, and blood sera were collected at 30 and 90 min after SE, alongside brains, for biochemical, western blot and immunohistochemical analyses. Results from non-ovariectomised (NOVX) Proechimys were compared to ovariectomised (OVX) animals. Data from female Wistars were used as a positive control of SE inductions. SE latency was similar in NOVX, OVX, and female Wistars groups. However, the pilocarpine dose required to induce SE in Proechimys was higher (25- to 50-folds more). Despite a higher dose, Proechimys did not show strong SE like Wistars; they only reached stage 2 of the Racine scale. These data suggest that female Proechimys are resistant to SE induction. Glucose and progesterone levels increased at 30 min and returned to normal at 90 min after SE. A relevant fact because in humans and rodents, SE leads to hypoglycaemia after 30 min of SE and does not return to normal levels in a short time, a typical adverse effect of SE. In OVX animals, a decrease in GABAergic receptors within 90 min of SE may suggest that ovariectomy produces changes in the hippocampus, including a certain vulnerability to seizures. We speculate that progesterone and glucose increases form part of the compensatory mechanisms that provide resistance in Proechimys against SE induction.

Neuroprotective Effect of Intravitreal Single-Dose Lithium Chloride after Optic Nerve Injury in Rats

OBJECTIVE

Lithium is an old drug to control bipolar disorder. Moreover, it presents neuroprotective effects and supports neuronal plasticity. The aim of this study was to evaluate neuroprotective effect of intravitreal lithium after optic nerve injury.

METHODS

Three dosages of lithium chloride, including 2 pmol, 200 pmol, and 2 nmol, were injected intravitreally after rat optic nerve injury. Proteins expression were assessed by western blot. Nitric oxide (NO) metabolites were measured by Griess test. Visual evoked potential (VEP) and optical coherence tomography (OCT) measurement were performed after trauma induction, in addition to H & E and TUJ1 staining of ganglion cells.

RESULTS

Western blot depicted lithium can significantly increase antiapoptotic Bcl-2 protein level and reduce p-ERK, Toll-like receptor 4 (TLR4) and proapoptotic proteins such as Bax level in retinal tissue and Griess test reflected that NO metabolites level decreased in lithium treated eyes (P < .05). While, OCT showed no significant changes (P = .36 and P = .43 comparing treated group with trauma) in retinal ganglion cell layer thickness after lithium injection, VEP P2 wave amplitude increased significantly (P < .01) in lithium-treated eyes and its latency reduced (P < .05 for N1 wave and P < .01 for P2 wave). Tuj1 antibody-labeled retinal ganglion cells analyzing showed that the number of retinal ganglion cells were significantly higher in lithium treated eyes compared to untreated eyes with optic nerve injury.

CONCLUSION

It seems intravitreally lithium has optic nerve neuroprotective effects by various mechanisms like overexpression of antiapoptotic proteins, suppressing proinflammatory molecules and proapoptotic factors, and decreasing nitric oxide.

Beneficial effects of low-dose lithium on cognitive ability and pathological alteration of Alzheimer's disease transgenic mice model

Lithium has been shown to delay the progression of Alzheimer's disease to reduce the prevalence of dementia. However, its narrow therapeutic index and numerous toxic effects at conventional dosage limited its long-term use to older subjects. Here, we tested the effect of low-dose lithium on cognitive impairment and pathology alterations in a mouse model of Alzheimer's disease, the amyloid precursor protein/presenilin-1 (APP/PS1) transgenic mouse. We found that both chronic and acute administration of lithium dose-dependently increased in blood and brain tissues. Long-term administration of low-dose lithium does not affect the body weight of APP/PS1 mice, but can significantly improve spatial memory of APP/PS1 mice. Pathologically, it also reduced β-amyloid plague and p-tau levels. Therefore, our results show that long-term low-dose lithium can ameliorate cognitive dysfunction and pathological alterations of Alzheimer's disease transgenic mice, and provide a theoretical basis for the further application of low-dose lithium in Alzheimer's disease clinical treatment.

Chronic Lithium Treatment Increases Telomere Length in Parietal Cortex and Hippocampus of Triple-Transgenic Alzheimer's Disease Mice

Telomere length (TL) is a biomarker of cell aging, and its shortening has been linked to several age-related diseases. In Alzheimer's disease (AD), telomere shortening has been associated with neuroinflammation and oxidative stress. The majority of studies on TL in AD were based on leucocyte DNA, with little information about its status in the central nervous system. In addition to other neuroprotective effects, lithium has been implicated in the maintenance of TL. The present study aims to determine the effect of chronic lithium treatment on TL in different regions of the mouse brain, using a triple-transgenic mouse model (3xTg-AD). Eighteen transgenic and 22 wild-type (Wt) male mice were treated for eight months with chow containing 1.0 g (Li1) or 2.0 g (Li2) of lithium carbonate/kg, or standard chow (Li0). DNA was extracted from parietal cortex, hippocampus and olfactory epithelium and TL was quantified by real-time PCR. Chronic lithium treatment was associated with longer telomeres in the hippocampus (Li2, p = 0.0159) and in the parietal cortex (Li1, p = 0.0375) of 3xTg-AD compared to Wt. Our findings suggest that chronic lithium treatment does affect telomere maintenance, but the magnitude and nature of this effect depend on the working concentrations of lithium and characteristics of the tissue. This effect was observed when comparing 3xTg-AD with Wt mice, suggesting that the presence of AD pathology was required for the lithium modulation of TL.

Dual Role of Autophagy in Diseases of the Central Nervous System

Autophagy is a vital lysosomal degradation and recycling pathway in the eukaryotic cell, responsible for maintaining an intricate balance between cell survival and cell death, necessary for neuronal survival and function. This dual role played by autophagy raises the question whether this process is a protective or a destructive pathway, the contributor of neuronal cell death or a failed attempt to repair aberrant processes? Deregulated autophagy at different steps of the pathway, whether excessive or downregulated, has been proposed to be associated with neurodegenerative disorders such as Alzheimer's-, Huntington's-, and Parkinson's-disease, known for their intracellular accumulation of protein aggregates. Recent observations of impaired autophagy also appeared in psychiatric disorders such as schizophrenia and bipolar disorder suggesting an additional contribution to the pathophysiology of mental illness. Here we review the current understanding of autophagy's role in various neuropsychiatric disorders and, hitherto, the prevailing new potential autophagy-related therapeutic strategies for their treatment.

Cotinine improves visual recognition memory and decreases cortical Tau phosphorylation in the Tg6799 mice

Alzheimer's disease (AD) is associated with the progressive aggregation of hyperphosphorylated forms of the microtubule associated protein Tau in the central nervous system. Cotinine, the main metabolite of nicotine, reduced working memory deficits, synaptic loss, and amyloid β peptide aggregation into oligomers and plaques as well as inhibited the cerebral Tau kinase, glycogen synthase 3β (GSK3β) in the transgenic (Tg)6799 (5XFAD) mice. In this study, the effect of cotinine on visual recognition memory and cortical Tau phosphorylation at the GSK3β sites Serine (Ser)-396/Ser-404 and phospho-CREB were investigated in the Tg6799 and non-transgenic (NT) littermate mice. Tg mice showed short-term visual recognition memory impairment in the novel object recognition test, and higher levels of Tau phosphorylation when compared to NT mice. Cotinine significantly improved visual recognition memory performance increased CREB phosphorylation and reduced cortical Tau phosphorylation. Potential mechanisms underlying theses beneficial effects are discussed.

Lithium and memantine improve spatial memory impairment and neuroinflammation induced by β-amyloid 1-42 oligomers in rats

Alzheimer's disease (AD) is the most common cause of dementia in the elderly. The main hallmarks of this disease include progressive cognitive dysfunction and an accumulation of soluble oligomers of β-amyloid (Aβ) 1-42 peptide. In this research, we show the effects of lithium and memantine on spatial memory and neuroinflammation in an Aβ1-42 oligomers-induced animal model of dementia in rats. Aβ 1-42 oligomers were administered intrahippocampally to male wistar rats to induce dementia. Oral treatments with memantine (5mg/kg), lithium (5mg/kg), or both drugs in combination were performed over a period of 17days. 14days after the administration of the Aβ1-42 oligomers, the radial arm-maze task was performed. At the end of the test period, the animals were euthanized, and the frontal cortex and hippocampus were removed for use in our analysis. Our results showed that alone treatments with lithium or memantine ameliorate the spatial memory damage caused by Aβ1-42. The animals that received combined doses of lithium and memantine showed better cognitive performance in their latency time and total errors to find food when compared to the results from alone treatments. Moreover, in our study, lithium and/or memantine were able to reverse the decreases observed in the levels of interleukin (IL)-4 that were induced by Aβ1-42 in the frontal cortex. In the hippocampus, only memantine and the association of memantine and lithium were able to reverse this effect. Alone doses of lithium and memantine or the association of lithium and memantine caused reductions in the levels of IL-1β in the frontal cortex and hippocampus, and decreased the levels of TNF-α in the hippocampus. Taken together, these data suggest that lithium and memantine might be a potential therapy against cognitive impairment and neuroinflammation induced by Aβ1-42, and their association may be a promising alternative to be investigated in the treatment of AD-like dementia.

L-F001, a Multifunction ROCK Inhibitor Prevents 6-OHDA Induced Cell Death Through Activating Akt/GSK-3beta and Nrf2/HO-1 Signaling Pathway in PC12 Cells and Attenuates MPTP-Induced Dopamine Neuron Toxicity in Mice

Amounting evidences demonstrated that Rho/Rho-associated kinase (ROCK) might be a novel target for the therapy of Parkinson's disease (PD). Recently, we synthesized L-F001 and revealed it was a potent ROCK inhibitor with multifunctional effects. Here we investigated the effects of L-F001 in PD models. We found that L-F001 potently attenuated 6-OHDA-induced cytotoxicity in PC12 cells and significantly decreased intracellular reactive oxygen species (ROS), prevented the 6-OHDA-induced decline of mitochondrial membrane potential and intracellular GSH levels. In addition, L-F001 increased Akt and GSK-3beta phosphorylation and induced the nuclear Nrf2 and HO-1 expression in a time- and concentration-dependent manner. Moreover, L-F001 restored the levels of p-Akt and p-GSK-3beta (Ser9) as well as HO-1 expression reduced by 6-OHDA. Those effects were blocked by the specific PI3K inhibitor, LY294002, indicating the involvement of Akt/GSK-3beta pathway in the neuroprotective effect of L-F001. In addition, L-F001 significantly attenuated the tyrosinehydroxylase immunoreactive cell loss in 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine (MPTP)-induced mice PD model. Together, our findings suggest that L-F001 prevents 6-OHDA-induced cell death through activating Akt/GSK-3beta and Nrf2/HO-1 signaling pathway and attenuates MPTP-induced dopaminergic neuron toxicity in mice. L-F001 might be a promising drug candidate for PD.

Neuroprotective effect of lithium after pilocarpine-induced status epilepticus in mice

Status epilepticus is the most common serious neurological condition triggered by abnormal electrical activity, leading to severe and widespread cell loss in the brain. Lithium has been one of the main drugs used for the treatment of bipolar disorder for decades, and its anticonvulsant and neuroprotective properties have been described in several neurological disease models. However, the therapeutic mechanisms underlying lithium's actions remain poorly understood. The muscarinic receptor agonist pilocarpine is used to induce status epilepticus, which is followed by hippocampal damage. The present study was designed to investigate the effects of lithium post-treatment on seizure susceptibility and hippocampal neuropathological changes following pilocarpine-induced status epilepticus. Status epilepticus was induced by administration of pilocarpine hydrochloride (320 mg/kg, i.p.) in C57BL/6 mice at 8 weeks of age. Lithium (80 mg/kg, i.p.) was administered 15 minutes after the pilocarpine injection. After the lithium injection, status epilepticus onset time and mortality were recorded. Lithium significantly delayed the onset time of status epilepticus and reduced mortality compared to the vehicle-treated group. Moreover, lithium effectively blocked pilocarpine-induced neuronal death in the hippocampus as estimated by cresyl violet and Fluoro-Jade B staining. However, lithium did not reduce glial activation following pilocarpine-induced status epilepticus. These results suggest that lithium has a neuroprotective effect and would be useful in the treatment of neurological disorders, in particular status epilepticus.

A new look at an old drug: neuroprotective effects and therapeutic potentials of lithium salts

Increasing evidence highlights bipolar disorder as being associated with impaired neurogenesis, cellular plasticity, and resiliency, as well as with cell atrophy or loss in specific brain regions. This has led most recent research to focus on the possible neuroprotective effects of medications, and particularly interesting findings have emerged for lithium. A growing body of evidence from preclinical in vitro and in vivo studies has in fact documented its neuroprotective effects from different insults acting on cellular signaling pathways, both preventing apoptosis and increasing neurotrophins and cell-survival molecules. Furthermore, positive effects of lithium on neurogenesis, brain remodeling, angiogenesis, mesenchymal stem cells functioning, and inflammation have been revealed, with a key role played through the inhibition of the glycogen synthase kinase-3, a serine/threonine kinase implicated in the pathogenesis of many neuropsychiatric disorders. These recent evidences suggest the potential utility of lithium in the treatment of neurodegenerative diseases, neurodevelopmental disorders, and hypoxic-ischemic/traumatic brain injury, with positive results at even lower lithium doses than those traditionally considered to be antimanic. The aim of this review is to briefly summarize the potential benefits of lithium salts on neuroprotection and neuroregeneration, emphasizing preclinical and clinical evidence suggesting new therapeutic potentials of this drug beyond its mood stabilizing properties.

Long-Term Lithium Treatment Increases cPLA₂ and iPLA₂ Activity in Cultured Cortical and Hippocampal Neurons

Background: Experimental evidence supports the neuroprotective properties of lithium, with implications for the treatment and prevention of dementia and other neurodegenerative disorders. Lithium modulates critical intracellular pathways related to neurotrophic support, inflammatory response, autophagy and apoptosis. There is additional evidence indicating that lithium may also affect membrane homeostasis. Objective: To investigate the effect of lithium on cytosolic phospholipase A₂ (PLA₂) activity, a key player on membrane phospholipid turnover which has been found to be reduced in blood and brain tissue of patients with Alzheimer’s disease (AD). Methods: Primary cultures of cortical and hippocampal neurons were treated for 7 days with different concentrations of lithium chloride (0.02 mM, 0.2 mM and 2 mM). A radio-enzymatic assay was used to determine the total activity of PLA₂ and two PLA₂ subtypes: cytosolic calcium-dependent (cPLA₂); and calcium-independent (iPLA₂). Results: cPLA₂ activity increased by 82% (0.02 mM; p = 0.05) and 26% (0.2 mM; p = 0.04) in cortical neurons and by 61% (0.2 mM; p = 0.03) and 57% (2 mM; p = 0.04) in hippocampal neurons. iPLA₂ activity was increased by 7% (0.2 mM; p = 0.04) and 13% (2 mM; p = 0.05) in cortical neurons and by 141% (0.02 mM; p = 0.0198) in hippocampal neurons. Conclusion: long-term lithium treatment increases membrane phospholipid metabolism in neurons through the activation of total, c- and iPLA₂. This effect is more prominent at sub-therapeutic concentrations of lithium, and the activation of distinct cytosolic PLA₂ subtypes is tissue specific, i.e., iPLA₂ in hippocampal neurons, and cPLA₂ in cortical neurons. Because PLA₂ activities are reported to be reduced in Alzheimer’s disease (AD) and bipolar disorder (BD), the present findings provide a possible mechanism by which long-term lithium treatment may be useful in the prevention of the disease.

Indirubin-3-Oxime Effectively Prevents 6OHDA-Induced Neurotoxicity in PC12 Cells via Activating MEF2D Through the Inhibition of GSK3β

Indirubin-3-oxime (I3O), a synthetic derivative of indirubin, was originally designed as potent inhibitors of cyclin-dependent kinases (CDKs) and glycogen synthase kinase 3β (GSK3β) for leukemia therapy. In the current study, we have shown, for the first time, that I3O prevented 6-hydroxydopamine (6OHDA)-induced neuronal apoptosis and intracellular reactive oxygen species accumulation in PC12 cells in a concentration-dependent manner. GSK3β inhibitors but not CDK5 inhibitors reduced the neurotoxicity induced by 6OHDA. Moreover, the activation of GSK3β was observed after 6OHDA treatment. Furthermore, 6OHDA substantially decreased the transcriptional activity of myocyte enhancer factor 2D (MEF2D), a transcription factor that plays an important role in dopaminergic neuron survival, and reduced nuclear localized MEF2D expression. Interestingly, indirubin-3-oxime and GSK3β inhibitors prevented 6OHDA-induced dysregulation of MEF2D. In addition, short hairpin RNA-mediated decrease of MEF2D expression significantly abolished the neuroprotective effects of indirubin-3-oxime. Collectively, our results strongly suggested that indirubin-3-oxime prevented 6OHDA-induced neurotoxicity via activating MEF2D, possibly through the inhibition of GSK3β. In view of the capability of indirubin-3-oxime to cross the blood-brain barrier, our findings further indicated that indirubin-3-oxime might be a novel drug candidate for neurodegenerative disorders, including Parkinson's disease in particular.

Lithium protects against methamphetamine-induced neurotoxicity in PC12 cells via Akt/GSK3β/mTOR pathway

Methamphetamine (MA) is neurotoxic, especially in dopaminergic neurons. Long-lasting exposure to MA causes psychosis and increases the risk of Parkinson's disease. Lithium (Li) is a known mood stabilizer and has neuroprotective effects. Previous studies suggest that MA exposure decreases the phosphorylation of Akt/GSK3β pathway in vivo, whereas Li facilitates the phosphorylation of Akt/GSK3β pathway. Moreover, GSK3β and mTOR are implicated in the locomotor sensitization induced by psychostimulants and mTOR plays a critical role in MA induced toxicity. However, the effect of MA on Akt/GSK3β/mTOR pathway has not been fully investigated in vitro. Here, we found that MA exposure significantly dephosphorylated Akt/GSK3β/mTOR pathway in PC12 cells. In addition, Li remarkably attenuated the dephosphorylation effect of MA exposure on Akt/GSK3β/mTOR pathway. Furthermore, Li showed obvious protective effects against MA toxicity and LY294002 (Akt inhibitor) suppressed the protective effects of Li. Together, MA exposure dephosphorylates Akt/GSK3β/mTOR pathway in vitro, while lithium protects against MA-induced neurotoxicity via phosphorylation of Akt/GSK3β/mTOR pathway.

Calcium-dependent intracellular signal pathways in primary cultured adipocytes and ANK3 gene variation in patients with bipolar disorder and healthy controls

Bipolar disorder (BD) is a chronic psychiatric disorder of public health importance affecting >1% of the Swedish population. Despite progress, patients still suffer from chronic mood switches with potential severe consequences. Thus, early detection, diagnosis and initiation of correct treatment are critical. Cultured adipocytes from 35 patients with BD and 38 healthy controls were analysed using signal pathway reporter assays, that is, protein kinase C (PKC), protein kinase A (PKA), mitogen-activated protein kinases (extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK)), Myc, Wnt and p53. The levels of activated target transcriptional factors were measured in adipocytes before and after stimulation with lithium and escitalopram. Variations were analysed in the loci of 25 different single-nucleotide polymorphisms (SNPs). Activation of intracellular signals in several pathways analysed were significantly higher in patients than in healthy controls upon drug stimulation, especially with escitalopram stimulation of PKC, JNK and Myc, as well as lithium-stimulated PKC, whereas no meaningful difference was observed before stimulation. Univariate analyses of contingency tables for 80 categorical SNP results versus diagnoses showed a significant link with the ANK3 gene (rs10761482; likelihood ratio χ(2)=4.63; P=0.031). In a multivariate ordinal logistic fit for diagnosis, a backward stepwise procedure selected ANK3 as the remaining significant predictor. Comparison of the escitalopram-stimulated PKC activity and the ANK3 genotype showed them to add their share of the diagnostic variance, with no interaction (15% of variance explained, P<0.002). The study is cross-sectional with no longitudinal follow-up. Cohorts are relatively small with no medication-free patients, and there are no 'ill patient' controls. It takes 3 to 4 weeks of culture to expand adipocytes that may change epigenetic profiles but remove the possibility of medication effects. Abnormalities in the reactivity of intracellular signal pathways to stimulation and the ANK3 genotype may be associated with pathogenesis of BD. Algorithms using biological patterns such as pathway reactivity together with structural genetic SNP data may provide opportunities for earlier detection and effective treatment of BD.

The protective influence of selenium on oxidant disturbances in brain of rats exposed to lithium

For more than sixty years lithium carbonate has been used in medicine. However, during its administration different side effects including oxidative stress can occur. Selenium belongs to essential elements possessing antioxidant properties. This study aimed at evaluating if selenium could be used as a protective adjuvant in lithium therapy. The experiment was performed on four groups of Wistar rats: I (control), II (Li), III (Se), IV (Li + Se) treated with saline, lithium carbonate (2.7 mg Li/kg b.w.), sodium selenite (0.5 mg Se/kg b.w.) and lithium carbonate (2.7 mg Li/kg b.w.) + sodium selenite (0.5 mg Se/kg b.w.), respectively. All substances were administered as water solutions by stomach tube for 3 or 6 weeks. Catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) as well as malonyldialdehyde (MDA) were determined in brain homogenates. Lithium slightly enhanced MDA and depressed CAT and SOD after 6 weeks as well as GPx after 3 weeks. Selenium co-administration showed tendency to restore the disturbed parameters. Selenium alone and given with lithium significantly increased GPx vs. Li-treated group after 3 weeks. Having regarded the outcomes of this study, the research on application of selenium during lithium treatment seems to be worth continuation.

Glial pathology in bipolar disorder: potential therapeutic implications

Bipolar disorder (BD) is a chronic and severe mental disorder with recurrent episodes of mania and depression. In addition to neuronal alterations, accumulating evidences have revealed the importance of glial system in pathophysiology and phenotype of the illness. Postmortem studies have repeatedly demonstrated the alterations in glial cells and its functions in patients with BD. The activated microglia and inflammatory cytokines are proposed to be the potential biomarkers that may help to predict disease exacerbation in BD. On the other hand, anti-BD drugs have been shown to produce profound effects on glial activity, which not only contributes to the therapeutic efficacy, but may also provide a potential target for the drug development of BD. We will focus on the recent development of glial abnormalities and potential therapeutic benefits targeted to glial modulation in BD.

Review of lithium effects on immune cells

One of the remarkable discoveries in the field of psychopharmacology from late 1940s is Lithium (Li) that reminds of old but still gold. It continues to be a distinctive mood stabilizer that matches various standards recommended for mood stabilizers. Apart from this Li is also known to affect immune cell functions. Lithium response and regulations of different immune cells in bipolar patients, related immune disorders are not well defined. Here, we provide an overview of literature with regard to Li's effects on different immune cells. However, the use of Li is currently limited to bipolar disorders and there is no empirical evidence for immune cell disorders. The objective of this article is to provide the evaluations of Li responses towards the different immune cells based on the existing studies. Further, more studies are needed to understand the mechanistic basis and heterogeneous responses of Li's effect in bipolar, also unravel relative immune disorders.

Therapeutic benefits of delayed lithium administration in the neonatal rat after cerebral hypoxia-ischemia

Aim

We have previously shown that lithium treatment immediately after hypoxia-ischemia (HI) in neonatal rats affords both short- and long-term neuroprotection. The aim of this study was to evaluate possible therapeutic benefits when lithium treatment was delayed 5 days, a time point when most cell death is over.

Methods

Eight-day-old male rats were subjected to unilateral HI and 2 mmol/kg lithium chloride was injected intraperitoneally 5 days after the insult. Additional lithium injections of 1 mmol/kg were administered at 24 h intervals for the next 14 days. Brain injury was evaluated 12 weeks after HI. Serum cytokine measurements and behavioral analysis were performed before sacrificing the animals.

Results

Brain injury, as indicated by tissue loss, was reduced by 38.7%, from 276.5±27.4 mm³ in the vehicle-treated group to 169.3±25.9 mm³ in the lithium-treated group 12 weeks after HI (p<0.01). Motor hyperactivity and anxiety-like behavior after HI were normalized by lithium treatment. Lithium treatment increased neurogenesis in the dentate gyrus as indicated by doublecortin labeling. Serum cytokine levels, including IL-1α, IL-1β, and IL-6, were still elevated as late as 5 weeks after HI, but lithium treatment normalized these cytokine levels.

Conclusions

Delayed lithium treatment conferred long-term neuroprotection in neonatal rats after HI, and this opens a new avenue for future development of treatment strategies for neonatal brain injury that can be administered after the acute injury phase.

A review: treatment of Alzheimer's disease discovered in repurposed agents

BACKGROUND/AIMS

Many compounds that have already been approved for alternate diagnoses have been studied in relation to Alzheimer's disease (AD). The purpose of this review is to summarize these studies and discuss the rationale and benefits of repurposing drugs for AD treatment.

METHODS

Studies of drugs related to AD treatment that were relevant to a disease-modifying mechanism of action (MOA) and are already approved by the Food and Drug Administration for non-AD diagnoses were collected from PubMed.

RESULTS

Many drugs already approved for the treatment of other diseases have been studied in relation to AD treatment. Numerous drugs with known toxicity profiles have the potential to be repurposed as a treatment for AD.

CONCLUSION

Known MOA, toxicology, and pharmacodynamic profiles would accelerate the process and increase the odds of finding a more timely disease-modifying treatment for AD.

Lithium: a versatile tool for understanding renal physiology

By virtue of its unique interactions with kidney cells, lithium became an important research tool in renal physiology and pathophysiology. Investigators have uncovered the intricate relationships of lithium with the vasopressin and aldosterone systems, and the membrane channels or transporters regulated by them. While doing so, their work has also led to 1) questioning the role of adenylyl cyclase activity and prostaglandins in lithium-induced suppression of aquaporin-2 gene transcription; 2) unraveling the role of purinergic signaling in lithium-induced polyuria; and 3) highlighting the importance of the epithelial sodium channel (ENaC) in lithium-induced nephrogenic diabetes insipidus (NDI). Lithium-induced remodeling of the collecting duct has the potential to shed new light on collecting duct remodeling in disease conditions, such as diabetes insipidus. The finding that lithium inhibits glycogen synthase kinase-3β (GSK3β) has opened an avenue for studies on the role of GSK3β in urinary concentration, and GSK isoforms in renal development. Finally, proteomic and metabolomic profiling of the kidney and urine in rats treated with lithium is providing insights into how the kidney adapts its metabolism in conditions such as acquired NDI and the multifactorial nature of lithium-induced NDI. This review provides state-of-the-art knowledge of lithium as a versatile tool for understanding the molecular physiology of the kidney, and a comprehensive view of how this tool is challenging some of our long-standing concepts in renal physiology, often with paradigm shifts, and presenting paradoxical situations in renal pathophysiology. In addition, this review points to future directions in research where lithium can lead the renal community.

Potential mechanisms of action of lithium in bipolar disorder. Current understanding

Lithium has been used for over half a century for the treatment of bipolar disorder as the archetypal mood stabilizer, and has a wealth of empirical evidence supporting its efficacy in this role. Despite this, the specific mechanisms by which lithium exerts its mood-stabilizing effects are not well understood. Given the inherently complex nature of the pathophysiology of bipolar disorder, this paper aims to capture what is known about the actions of lithium ranging from macroscopic changes in mood, cognition and brain structure, to its effects at the microscopic level on neurotransmission and intracellular and molecular pathways. A comprehensive literature search of databases including MEDLINE, EMBASE and PsycINFO was conducted using relevant keywords and the findings from the literature were then reviewed and synthesized. Numerous studies report that lithium is effective in the treatment of acute mania and for the long-term maintenance of mood and prophylaxis; in comparison, evidence for its efficacy in depression is modest. However, lithium possesses unique anti-suicidal properties that set it apart from other agents. With respect to cognition, studies suggest that lithium may reduce cognitive decline in patients; however, these findings require further investigation using both neuropsychological and functional neuroimaging probes. Interestingly, lithium appears to preserve or increase the volume of brain structures involved in emotional regulation such as the prefrontal cortex, hippocampus and amygdala, possibly reflecting its neuroprotective effects. At a neuronal level, lithium reduces excitatory (dopamine and glutamate) but increases inhibitory (GABA) neurotransmission; however, these broad effects are underpinned by complex neurotransmitter systems that strive to achieve homeostasis by way of compensatory changes. For example, at an intracellular and molecular level, lithium targets second-messenger systems that further modulate neurotransmission. For instance, the effects of lithium on the adenyl cyclase and phospho-inositide pathways, as well as protein kinase C, may serve to dampen excessive excitatory neurotransmission. In addition to these many putative mechanisms, it has also been proposed that the neuroprotective effects of lithium are key to its therapeutic actions. In this regard, lithium has been shown to reduce the oxidative stress that occurs with multiple episodes of mania and depression. Further, it increases protective proteins such as brain-derived neurotrophic factor and B-cell lymphoma 2, and reduces apoptotic processes through inhibition of glycogen synthase kinase 3 and autophagy. Overall, it is clear that the processes which underpin the therapeutic actions of lithium are sophisticated and most likely inter-related.

Off label use of lithium in the treatment of Huntington's disease: A case series

Huntington's disease is characterized by choreic movements, psychiatric disorders, striatal atrophy with selective small neuronal loss, and autosomal dominant inheritance. The genetic abnormality is CAG expansion in Huntingtin gene. Newer therapeutic strategies are evolving to treat this progressive disorder. The neuroprotective agents are one such group of drugs being tried. Lithium has been used to treat Huntington's disease in the past due to its neuroprotective effects. Though the precise mechanism of action is not clear, Lithium can directly or indirectly modulate proteins involved in neuronal survival/differentiation which may account for its neuroprotective effects. We report three patients with Huntington's disease in whom Lithium prevented the progression of chorea and also helped stabilize mood.

Therapeutic targets of brain insulin resistance in sporadic Alzheimer's disease

Growing evidence supports roles for brain insulin and insulin-like growth factor (IGF) resistance and metabolic dysfunction in the pathogenesis of Alzheimer's disease (AD). Whether the underlying problem stems from a primary disorder of central nervous system (CNS) neurons and glia, or secondary effects of systemic diseases such as obesity, Type 2 diabetes, or metabolic syndrome, the end-results include impaired glucose utilization, mitochondrial dysfunction, increased oxidative stress, neuroinflammation, and the propagation of cascades that result in the accumulation of neurotoxic misfolded, aggregated, and ubiquitinated fibrillar proteins. This article reviews the roles of impaired insulin and IGF signaling to AD-associated neuronal loss, synaptic disconnection, tau hyperphosphorylation, amyloid-beta accumulation, and impaired energy metabolism, and discusses therapeutic strategies and lifestyle approaches that could be used to prevent, delay the onset, or reduce the severity of AD. Finally, it is critical to recognize that AD is heterogeneous and has a clinical course that fully develops over a period of several decades. Therefore, early and multi-modal preventive and treatment approaches should be regarded as essential.

Therapeutic targets of brain insulin resistance in sporadic Alzheimer's disease

Growing evidence supports roles for brain insulin and insulin-like growth factor (IGF) resistance and metabolic dysfunction in the pathogenesis of Alzheimer's disease (AD). Whether the underlying problem stems from a primary disorder of central nervous system (CNS) neurons and glia, or secondary effects of systemic diseases such as obesity, Type 2 diabetes, or metabolic syndrome, the end-results include impaired glucose utilization, mitochondrial dysfunction, increased oxidative stress, neuroinflammation, and the propagation of cascades that result in the accumulation of neurotoxic misfolded, aggregated, and ubiquitinated fibrillar proteins. This article reviews the roles of impaired insulin and IGF signaling to AD-associated neuronal loss, synaptic disconnection, tau hyperphosphorylation, amyloid-beta accumulation, and impaired energy metabolism, and discusses therapeutic strategies and lifestyle approaches that could be used to prevent, delay the onset, or reduce the severity of AD. Finally, it is critical to recognize that AD is heterogeneous and has a clinical course that fully develops over a period of several decades. Therefore, early and multi-modal preventive and treatment approaches should be regarded as essential.

Midlife predictors of Alzheimer's disease

Factors contributing to increased risk for Alzheimer's disease (AD) include age, sex, genes, and family history of AD. Several risk factors for AD are endogenous; however, accumulating evidence implicates modifiable risk factors in the pathogenesis of AD. Although the continued task of identifying new genes will be critical to learning more about the disease, several research findings suggest that potentially alterable environmental factors influence genetic contributions, providing targets for disease prevention and treatment. Here, we review midlife risk factors for AD, and address the potential for therapeutic intervention in midlife.