Neuroprotective effect of chronic lithium treatment against hypoxia in specific brain regions with upregulation of cAMP response element binding protein and brain-derived neurotrophic factor but not nerve growth factor: comparison with acute lithium treatment

Chronic REM sleep deprivation leads to manic- and OCD-related behaviors, and decreases hippocampal BDNF expression in female rats

BACKGROUND

Rapid-eye movement (REM) sleep deprivation (SD) can induce manic-like behaviors in rodents. On the other hand, lithium, as one of the oldest drugs used in neuropsychiatric disorders, is still one of the best drugs for the treatment and control of bipolar disorder. In this study, we aimed to investigate the role of chronic short-term REM SD in the induction of manic-like behaviors in female rats.

METHODS

The rats were exposed to REM SD for 14 days (6 hours/day). Lithium was intraperitoneally injected at the doses of 10, 50, and 100 mg/kg.

RESULTS

REM SD induced hyperactivity and OCD-like behavior, and decreased anxiety, depressive-like behavior, and pain subthreshold. REM SD also impaired passive avoidance memory and decreased hippocampal brain-derived neurotrophic factor (BDNF) expression level. Lithium at the doses of 50 and 100 mg/kg partly and completely abolished these effects, respectively. However, lithium (100 mg/kg) increased BDNF expression level in control and sham REM SD rats with no significant changes in behavior.

CONCLUSIONS

Chronic short-term REM SD may induce a mania-like model and lead to OCD-like behavior and irritability. In the present study, we demonstrated a putative rodent model of mania induced by chronic REM SD in female rats. We suggest that future studies should examine behavioral and mood changes following chronic REM SD in both sexes. Furthermore, the relationship between manic-like behaviors and chronic REM SD should be investigated.

Lithium treatment reverses irradiation-induced changes in rodent neural progenitors and rescues cognition

Cranial radiotherapy in children has detrimental effects on cognition, mood, and social competence in young cancer survivors. Treatments harnessing hippocampal neurogenesis are currently of great relevance in this context. Lithium, a well-known mood stabilizer, has both neuroprotective, pro-neurogenic as well as antitumor effects, and in the current study we introduced lithium treatment 4 weeks after irradiation. Female mice received a single 4 Gy whole-brain radiation dose on postnatal day (PND) 21 and were randomized to 0.24% Li2CO₃ chow or normal chow from PND 49 to 77. Hippocampal neurogenesis was assessed on PND 77, 91, and 105. We found that lithium treatment had a pro-proliferative effect on neural progenitors, but neuronal integration occurred only after it was discontinued. Also, the treatment ameliorated deficits in spatial learning and memory retention observed in irradiated mice. Gene expression profiling and DNA methylation analysis identified two novel factors related to the observed effects, Tppp, associated with microtubule stabilization, and GAD2/65, associated with neuronal signaling. Our results show that lithium treatment reverses irradiation-induced loss of hippocampal neurogenesis and cognitive impairment even when introduced long after the injury. We propose that lithium treatment should be intermittent in order to first make neural progenitors proliferate and then, upon discontinuation, allow them to differentiate. Our findings suggest that pharmacological treatment of cognitive so-called late effects in childhood cancer survivors is possible.

Molecular and Therapeutic Aspects of Hyperbaric Oxygen Therapy in Neurological Conditions

In hyperbaric oxygen therapy (HBOT), the subject is placed in a chamber containing 100% oxygen gas at a pressure of more than one atmosphere absolute. This treatment is used to hasten tissue recovery and improve its physiological aspects, by providing an increased supply of oxygen to the damaged tissue. In this review, we discuss the consequences of hypoxia, as well as the molecular and physiological processes that occur in subjects exposed to HBOT. We discuss the efficacy of HBOT in treating neurological conditions and neurodevelopmental disorders in both humans and animal models. We summarize by discussing the challenges in this field, and explore future directions that will allow the scientific community to better understand the molecular aspects and applications of HBOT for a wide variety of neurological conditions.

Effects of lithium and valproic acid on BDNF protein and gene expression in an in vitro human neuron-like model of degeneration

One of the common effects of lithium (Li) and valproic acid (VPA) is their ability to protect against excitotoxic insults. Neurodegenerative and neuropsychiatric diseases may be also associated with altered trophic support of brain-derived neurotrophic factor (BDNF), the most widely distributed neurotrophin in the central nervous system. However, despite these evidences, the effect of Li-VPA combination on BDNF after excitoxic insult has been inadequately investigated. We address this issue by exposing a human neuroblastoma cell line (SH-SY5Y) to neurotoxic concentration of L-glutamate and exploring whether the neuroprotective action of Li-VPA on these cells is associated with changes in BDNF protein and mRNA levels. The results showed that pre-incubation of Li-VPA abolished the toxic effect of glutamate on SH-SY5Y cell survival and this neuroprotective effect was associated with increased synthesis and mRNA expression of BDNF after 24 and 48 h of incubation. In conclusion, this study demonstrates that the neuroprotective effects of Li-VPA against glutamate-induced neurotoxicity in SH-SY5Y neuroblastoma cells is associated with increased synthesis and mRNA expression of BDNF. These data further support the idea that these two drugs can be used for prevention and/or treatment of glutamate-related neurodegenerative disorders.

Brain-derived neurotrophic factor levels and bipolar disorder in patients in their first depressive episode: 3-year prospective longitudinal study

BACKGROUND

Early identification of patients with bipolar disorder during their first depressive episode is beneficial to the outcome of the disorder and treatment, but traditionally this has been a great challenge to clinicians. Recently, brain-derived neurotrophic factor (BDNF) has been suggested to be involved in the pathophysiology of bipolar disorder and major depressive disorder (MDD), but it is not clear whether BDNF levels can be used to predict bipolar disorder among patients in their first major depressive episode.

AIMS

To explore whether BDNF levels can differentiate between MDD and bipolar disorder in the first depressive episode.

METHOD

A total of 203 patients with a first major depressive episode as well as 167 healthy controls were recruited. After 3 years of bi-annual follow-up, 164 patients with a major depressive episode completed the study, and of these, 21 were identified as having bipolar disorder and 143 patients were diagnosed as having MDD. BDNF gene expression and plasma levels at baseline were compared among the bipolar disorder, MDD and healthy control groups. Logistic regression and decision tree methods were applied to determine the best model for predicting bipolar disorder at the first depressive episode.

RESULTS

At baseline, patients in the bipolar disorder and MDD groups showed lower BDNF mRNA levels (P<0.001 and P = 0.02 respectively) and plasma levels (P = 0.002 and P = 0.01 respectively) compared with healthy controls. Similarly, BDNF levels in the bipolar disorder group were lower than those in the MDD group. These results showed that the best model for predicting bipolar disorder during a first depressive episode was a combination of BDNF mRNA levels with plasma BDNF levels (receiver operating characteristics (ROC) = 0.80, logistic regression; ROC = 0.84, decision tree).

CONCLUSIONS

Our findings suggest that BDNF levels may serve as a potential differential diagnostic biomarker for bipolar disorder in a patient's first depressive episode.

A new avenue for lithium: intervention in traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of disability and death from trauma to central nervous system (CNS) tissues. For patients who survive the initial injury, TBI can lead to neurodegeneration as well as cognitive and motor deficits, and is even a risk factor for the future development of neurodegenerative disorders such as Alzheimer's disease. Preclinical studies of multiple neuropathological and neurodegenerative disorders have shown that lithium, which is primarily used to treat bipolar disorder, has considerable neuroprotective effects. Indeed, emerging evidence now suggests that lithium can also mitigate neurological deficits incurred from TBI. Lithium exerts neuroprotective effects and stimulates neurogenesis via multiple signaling pathways; it inhibits glycogen synthase kinase-3 (GSK-3), upregulates neurotrophins and growth factors (e.g., brain-derived neurotrophic factor (BDNF)), modulates inflammatory molecules, upregulates neuroprotective factors (e.g., B-cell lymphoma-2 (Bcl-2), heat shock protein 70 (HSP-70)), and concomitantly downregulates pro-apoptotic factors. In various experimental TBI paradigms, lithium has been shown to reduce neuronal death, microglial activation, cyclooxygenase-2 induction, amyloid-β (Aβ), and hyperphosphorylated tau levels, to preserve blood-brain barrier integrity, to mitigate neurological deficits and psychiatric disturbance, and to improve learning and memory outcome. Given that lithium exerts multiple therapeutic effects across an array of CNS disorders, including promising results in preclinical models of TBI, additional clinical research is clearly warranted to determine its therapeutic attributes for combating TBI. Here, we review lithium's exciting potential in ameliorating physiological as well as cognitive deficits induced by TBI.

Molecular actions and clinical pharmacogenetics of lithium therapy

Mood disorders, including bipolar disorder and depression, are relatively common human diseases for which pharmacological treatment options are often not optimal. Among existing pharmacological agents and mood stabilizers used for the treatment of mood disorders, lithium has a unique clinical profile. Lithium has efficacy in the treatment of bipolar disorder generally, and in particular mania, while also being useful in the adjunct treatment of refractory depression. In addition to antimanic and adjunct antidepressant efficacy, lithium is also proven effective in the reduction of suicide and suicidal behaviors. However, only a subset of patients manifests beneficial responses to lithium therapy and the underlying genetic factors of response are not exactly known. Here we discuss preclinical research suggesting mechanisms likely to underlie lithium's therapeutic actions including direct targets inositol monophosphatase and glycogen synthase kinase-3 (GSK-3) among others, as well as indirect actions including modulation of neurotrophic and neurotransmitter systems and circadian function. We follow with a discussion of current knowledge related to the pharmacogenetic underpinnings of effective lithium therapy in patients within this context. Progress in elucidation of genetic factors that may be involved in human response to lithium pharmacology has been slow, and there is still limited conclusive evidence for the role of a particular genetic factor. However, the development of new approaches such as genome-wide association studies (GWAS), and increased use of genetic testing and improved identification of mood disorder patients sub-groups will lead to improved elucidation of relevant genetic factors in the future.

Four weeks lithium treatment alters neuronal dendrites in the rat hippocampus

A large body of evidence from molecular, cellular and human studies suggests that lithium may enhance synaptic plasticity, which may be associated with its therapeutic efficacy. However, only a small number of studies have directly assessed this. To determine whether lithium treatment alters structural synaptic plasticity, this study examined the effect of 4 wk lithium treatment on the amount and distribution of dendrites in the dentate gyrus (DG) and hippocampal area CA1 of young adult rats. Following 4 wk lithium or control chow feeding, animals were decapitated, the hippocampi were prepared and stained using a rapid Golgi staining technique and the amount and distribution of the dendritic branching was evaluated using Sholl analyses (method of concentric circles). In the DG, lithium treatment increased the amount and distribution of dendritic branches in the proximal half of dendritic trees of the granule cells and reduced branching in the distal half. In area CA1, the same treatment also increased the number of dendritic branches in the proximal half of apical dendritic trees of CA1 pyramidal cells and reduced branching in the distal half of apical dendritic trees but had no effect on basilar dendritic trees. The lithium treatment altered the total density of dendritic trees in neither the DG nor area CA1. These findings suggest that, in the DG and apical CA1, chronic lithium treatment rearranges neuronal morphology to increase dendritic branching and distribution to where major afferent input is received.

Therapeutic potential of mood stabilizers lithium and valproic acid: beyond bipolar disorder

The mood stabilizers lithium and valproic acid (VPA) are traditionally used to treat bipolar disorder (BD), a severe mental illness arising from complex interactions between genes and environment that drive deficits in cellular plasticity and resiliency. The therapeutic potential of these drugs in other central nervous system diseases is also gaining support. This article reviews the various mechanisms of action of lithium and VPA gleaned from cellular and animal models of neurologic, neurodegenerative, and neuropsychiatric disorders. Clinical evidence is included when available to provide a comprehensive perspective of the field and to acknowledge some of the limitations of these treatments. First, the review describes how action at these drugs' primary targets--glycogen synthase kinase-3 for lithium and histone deacetylases for VPA--induces the transcription and expression of neurotrophic, angiogenic, and neuroprotective proteins. Cell survival signaling cascades, oxidative stress pathways, and protein quality control mechanisms may further underlie lithium and VPA's beneficial actions. The ability of cotreatment to augment neuroprotection and enhance stem cell homing and migration is also discussed, as are microRNAs as new therapeutic targets. Finally, preclinical findings have shown that the neuroprotective benefits of these agents facilitate anti-inflammation, angiogenesis, neurogenesis, blood-brain barrier integrity, and disease-specific neuroprotection. These mechanisms can be compared with dysregulated disease mechanisms to suggest core cellular and molecular disturbances identifiable by specific risk biomarkers. Future clinical endeavors are warranted to determine the therapeutic potential of lithium and VPA across the spectrum of central nervous system diseases, with particular emphasis on a personalized medicine approach toward treating these disorders.

Blood oxygen level dependent angiography (BOLDangio) and its potential applications in cancer research

Clinically, development of anti-angiogenic drugs for cancer therapy is pivotal. Longitudinal monitoring of tumour angiogenesis can help clinicians determine the effectiveness of anti-angiogenic therapy. Blood oxygen level dependent (BOLD) effect has been widely used for functional imaging and tumour oxygenation assessment. In this study, the BOLD effect is investigated under different levels of oxygen inhalation for the development of a novel angiographic MRI technique, blood oxygen level dependent angiography (BOLDangio). Under short-term (<10 min) generalized hypoxia induced by inhalation of 8% oxygen, we measure BOLD contrast as high as 25% from vessels at 9.4T using a simple gradient echo (GRE) pulse sequence. This produces high-resolution 2D and 3D maps of normal and tumour brain vasculature in less than 10 minutes. Additionally, this technique reliably detects metastatic tumours and tumour-induced intracranial hemorrhage. BOLDangio provides a sensitive research tool for MRI of vasculature under normal and pathological conditions. Thus, it may be applied as a simple monitoring technique for measuring the effectiveness of anti-angiogenic drugs in a preclinical environment.

Valproate alters dopamine signaling in association with induction of Par-4 protein expression

Chromatin remodeling through histone modifications has emerged as a key mechanism in the pathophysiology of psychiatric disorders. Valproate (VPA), a first-line medication for bipolar disorder, is known to have histone deacetylase (HDAC) inhibitor activity, but the relationship between its efficacy as a mood stabilizer and HDAC inhibitory activity is unclear. Here we provide evidence that prostate apoptosis response-4 (Par-4), an intracellular binding partner of dopamine D2 receptors (DRD2), plays a role in mediating the effectiveness of VPA. We found that chronic VPA treatment enhanced the expression of Par-4 in cultured neurons and adult mouse brains. This Par-4 induction phenomenon occurred at the transcriptional level and was correlated with an increase in histone H3 and H4 acetylation of the Par-4 promoter regions. Furthermore, chronic VPA treatment potentiated the suppression of the cAMP signaling cascade upon dopamine stimulation, which was blocked by sulpiride treatment. These results indicate that VPA potentiates DRD2 activity by enhancing Par-4 expression via a chromatin remodeling mechanism.

Neuroprotective effects of lithium treatment following hypoxic-ischemic brain injury in neonatal rats

PURPOSE

Increasing evidence indicates that lithium is a neuroprotective agent against transient focal and global ischemic injury in the adult animal. In the developing brain, lithium has shown protective effects against neuroapoptosis induced by drugs. This study was designed to investigate the neuroprotective effects of lithium on hypoxic-ischemic brain injury in the neonatal rat.

METHODS

Seven-day-old Sprague-Dawley rats underwent hypoxic-ischemic injury (HII) induced by ligation of the common carotid artery followed by exposure to ~2.5 h of hypoxia (~7% oxygen). After HII, rat pups were randomly assigned into two groups: a control group (n = 21), which received a daily subcutaneous injection of 0.9% normal saline for 14 days following HII; and a lithium group (n = 32), treated with daily injection of lithium chloride. N-acetylaspartate/creatinine, choline/creatinine, lipid/creatinine ratios at 1.3 ppm (Lip(1.3)/Cr) and 0.9 ppm (Lip(0.9)/Cr) lipid peaks were evaluated by proton magnetic resonance spectroscopy on the day of HII and on days 7 and 14 after HII. Infarct ratios based on magnetic resonance images were also determined at the same time points.

RESULTS

Seven days after HII, the Lip(1.3)/Cr and Lip(0.9)/Cr ratios as well as the infarct ratio were significantly lower in the lithium group than in the control group. The Lip(1.3)/Cr and Lip(0.9)/Cr ratios were significantly correlated with infarct ratio.

CONCLUSION

This study showed that post-HII treatment with lithium may have a neuroprotective effect in the immature brain. Further studies are needed to elucidate the mechanism of neuroprotective properties of lithium against HII-induced neonatal brain damage.

Morphometric post-mortem studies in bipolar disorder: possible association with oxidative stress and apoptosis

Despite extensive research in the last decades, the pathophysiology of bipolar disorder (BD) remains unclear. Access to post-mortem brain tissue of subjects who had BD offers an opportunity to investigate neurobiology and this approach has led to some progress, particularly, due to the availability of more sophisticated molecular and cellular biological methodologies and well characterized brain collections over the past decade. Here we review the findings of morphometric post-mortem studies in BD and interpret them in the context of a potential physiopathological mechanism involving oxidative stress and apoptosis. A review of the literature was conducted to identify post-mortem studies that investigated cellular changes such as number, density and size of neurons and glia, in brains of subjects with BD. We found decreased density of neurons and glia and decreased size of neurons in frontal and subcortical areas of the brain. Based on recent studies that found evidence of increased apoptosis and oxidative stress in BD, we hypothesize that the cell abnormalities described are due to an increase in the apoptotic process that can be triggered, through its intrinsic pathway, by the existence of an exacerbated production of reactive oxygen species and oxidative damage in the disease.

Lentivirally mediated GSK-3β silencing in the hippocampal dentate gyrus induces antidepressant-like effects in stressed mice

Inhibition of glycogen synthase kinase-3 (GSK-3) by pharmacological tools can produce antidepressant-like effects in rodents. However, the GSK-3 isoform(s) and brain region(s) involved in regulating these behavioural effects remain elusive. We studied the effects of bilateral intra-hippocampal injections of lentivirus-expressing short-hairpin (sh)RNA targeting GSK-3β on behavioural performance in mice subjected to chronic stress. Pre-injection of lentivirus-expressing GSK-3β shRNA into the hippocampal dentate gyrus significantly decreased immobility time in both forced swim and tail suspension tests, while the locomotor activity of these mice was unchanged. These results suggest that lentiviral GSK-3β shRNA injection induces antidepressant-like effects in chronically stressed mice. Under these conditions, the expression levels of GSK-3β were persistently and markedly reduced in the hippocampus following GSK-3β shRNA injection. To our knowledge, this is the first demonstration that a single injection of lentivirus-expressing GSK-3β shRNA in the hippocampal dentate gyrus of chronically stressed mice has antidepressant-like effects elicited by gene silencing.

Impaired nerve growth factor homeostasis in patients with bipolar disorder

OBJECTIVE

Neuro-trophins are critically involved in neuro-plasticity, the impairment of which is a major role-player in bipolar disorder (BD), and their altered levels have been recently advocated in the patho-physiology of this affective malady. The aim of this study, therefore, was to evaluate the plasma levels of nerve growth factor (NGF) in BD patients in comparison with control subjects.

METHODS

Forty-nine BD type-I individuals (30 in mania and 19 in euthymia) and 36 healthy controls were assessed by Mini-plus, Young mania and Hamilton depression rating scales. NGF levels were detected by ELISA.

RESULTS

Plasma NGF concentrations were decreased in BD patients when compared to that seen with controls. BD individuals in mania had lower NGF levels than euthymic patients or controls. NGF levels were negatively correlated with the severity of mania.

CONCLUSIONS

This is the first study to evaluate NGF levels in BD patients, providing further support to the hypothesis of impaired neuro-plasticity in BD. These data also suggest that NGF measurement could be used for the biological marker for manic state.

Interaction networks of lithium and valproate molecular targets reveal a striking enrichment of apoptosis functional clusters and neurotrophin signaling

The overall neurobiological mechanisms by which lithium and valproate stabilize mood in bipolar disorder patients have yet to be fully defined. The therapeutic efficacy and dissimilar chemical structures of these medications suggest that they perturb both shared and disparate cellular processes. To investigate key pathways and functional clusters involved in the global action of lithium and valproate, we generated interaction networks formed by well-supported drug targets. Striking functional similarities emerged. Intersecting nodes in lithium and valproate networks highlighted a strong enrichment of apoptosis clusters and neurotrophin signaling. Other enriched pathways included MAPK, ErbB, insulin, VEGF, Wnt and long-term potentiation indicating a widespread effect of both drugs on diverse signaling systems. MAPK1/3 and AKT1/2 were the most preponderant nodes across pathways suggesting a central role in mediating pathway interactions. The convergence of biological responses unveils a functional signature for lithium and valproate that could be key modulators of their therapeutic efficacy.

Detoxified extract of Rhus verniciflua stokes inhibits rotenone-induced apoptosis in human dopaminergic cells, SH-SY5Y

Rhus verniciflua Stokes (RVS), traditionally used as a food supplement and in traditional herbal medicine for centuries in Korea, is known to possess various pharmacological properties. Environmental neurotoxins such as rotenone, a specific inhibitor of complex I provide models of Parkinson's disease (PD) both in vivo and in vitro. In this study, we investigated the neuroprotective effect of RVS against rotenone-induced toxicity in human dopaminergic cells, SH-SY5Y. Cells exposed to rotenone for 24 h-induced cellular injury and apoptotic cell death. Pretreatment of cells with RVS provided significant protection to SH-SY5Y cells. Further, RVS offered remarkable protection against rotenone-induced oxidative stress and markedly inhibited mitochondrial membrane potential (MMP) disruption. RVS also attenuated the up-regulation of Bax, Caspase-9 and Caspase-3 and down-regulation of Bcl-2. Moreover, pretreatment with RVS prevented the decrease in tyrosine hydroxylase (TH) levels in SH-SY5Y cells. Interestingly, RVS conferred profound protection to human dopaminergic cells by preventing the downregulation of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). These results suggest that RVS may protect dopaminergic neurons against rotenone-induced apoptosis by multiple functions and contribute to neuroprotection in neurodegenerative diseases, such as PD.

Pharmacogenomics of mood stabilizers in the treatment of bipolar disorder

Bipolar disorder (BD) is a chronic and often severe psychiatric illness characterized by manic and depressive episodes. Among the most effective treatments, mood stabilizers represent the keystone in acute mania, depression, and maintenance treatment of BD. However, treatment response is a highly heterogeneous trait, thus emphasizing the need for a structured informational framework of phenotypic and genetic predictors. In this paper, we present the current state of pharmacogenomic research on long-term treatment in BD, specifically focusing on mood stabilizers. While the results provided so far support the key role of genetic factors in modulating the response phenotype, strong evidence for genetic predictors is still lacking. In order to facilitate implementation of pharmacogenomics into clinical settings (i.e., the creation of personalized therapy), further research efforts are needed.

Early life stressors and genetic influences on the development of bipolar disorder: the roles of childhood abuse and brain-derived neurotrophic factor

OBJECTIVES

Although there is increasing research exploring the psychosocial influences and biological underpinnings of bipolar disorder, relatively few studies have specifically examined the interplay between these factors in the development of this illness. Social-biological models within a developmental psychopathology perspective are necessary to advance our understanding of the processes involved in the onset and course of bipolar disorder. This article presents a review of the empirical literature linking childhood abuse to bipolar disorder, the research to date on the possible role of brain-derived neurotrophic factor (BDNF) in the development of this disorder, followed by a discussion of how childhood abuse may interact with BDNF.

METHODS

A literature search was conducted using Psycinfo to identify relevant articles on childhood abuse, BDNF, and bipolar disorder.

RESULTS

The extant research implicates both childhood abuse and BDNF in the etiology of bipolar disorder. Specifically, there is growing evidence associating early abuse to the development of bipolar disorder. Similarly, the BDNF Val66 allele has been linked with increased susceptibility to bipolar disorder. Based on existing research, a genetic diathesis-transactional stress model is proposed incorporating childhood abuse and the BDNF gene in the pathogenesis of bipolar disorder.

CONCLUSIONS

Although there is some support for this model, the relatively modest amount of relevant literature highlights the need for further research. An integrative theoretical framework including both social and biological processes in bipolar disorder is important for the development of effective prevention and treatment strategies for this disorder.

The neurotrophic and neuroprotective effects of psychotropic agents

Accumulating evidence suggests that psychotropic agents such as mood stabilizers, antidepressants, and antipsychotics realize their neurotrophic/neuroprotective effects by activating the mitogen activated protein kinaselextracellular signal-related kinase, PI3-kinase, and winglesslglycogen synthase kinase (GSK) 3 signaling pathways. These agents also upregulate the expression of trophic/protective molecules such as brain-derived neurotrophic factor, nerve growth factor, B-cell lymphoma 2, serine-threonine kinase, and Bcl-2 associated athanogene 1, and inactivate proapoptotic molecules such as GSK-3, They also promote neurogenesis and are protective in models of neurodegenerative diseases and ischemia. Most if not all, of this evidence was collected from animal studies that used clinically relevant treatment regimens. Furthermore, human imaging studies have found that these agents increase the volume and density of brain tissue, as well as levels of N-acetyl aspartate and glutamate in selected brain regions. Taken together, these data suggest that the neurotrophic/neuroprotective effects of these agents have broad therapeutic potential in the treatment, not only of mood disorders and schizophrenia, but also neurodegenerative diseases and ischemia.

Serum brain-derived neurotrophic factor in bipolar and unipolar depression: a potential adjunctive tool for differential diagnosis

The differential diagnosis of Bipolar Disorder (BD) and Major Depressive Disorder (MDD) is a diagnostic challenge during depressive episodes. Noteworthy, the proper differentiation between BD depressive state and MDD has important treatment implications. BDNF levels may be valuable adjunctive tool for this differential diagnosis. Ten subjects with MDD, forty with BD type I and thirty healthy comparison subjects were recruited. All subjects had BDNF serum levels measured and, in patients, BDNF serum levels were assessed during acute depressive episode. Optimal sensitivity and specificity of serum BDNF for the differential diagnosis of unipolar and bipolar depression were determined by the receiver operating characteristic (ROC) curve analysis, using a nonparametric approach. Serum BDNF levels in depressive BD patients were lower compared to MDD patients and controls (0.15+/-0.08, 0.35+/-0.08, and 0.38+/-0.12, respectively, p<0.001). The area under the curve (AUC) of the ROC analysis in BD depression vs. MDD was 0.95 (ranged from 0.89 to 1.00). Overall, the AUC of the ROC analysis (BD depression vs. MDD and controls) was 0.94 (95% CI 0.89 to 0.99, p<0.001). A proposed "best" cutoff of 0.26 resulted in 88% sensitivity and 90% specificity. Serum BDNF levels appear as a promising tool to discriminate bipolar from unipolar depression. Our results suggest the role of BDNF as an adjunctive tool to promote prompt and accurate diagnosis of BD. However, further investigation and replication of these results are warranted.

The role of lithium in the treatment of bipolar disorder: convergent evidence for neurotrophic effects as a unifying hypothesis

Lithium has been and continues to be the mainstay of bipolar disorder (BD) pharmacotherapy for acute mood episodes, switch prevention, prophylactic treatment, and suicide prevention. Lithium is also the definitive proof-of-concept agent in BD, although it has recently been studied in other psychoses as well as diverse neurodegenerative disorders. Its neurotrophic effects can be viewed as a unifying model to explain several integrated aspects of the pathophysiology of mood disorders and putative therapeutics for those disorders. Enhancing neuroprotection (which directly involves neurotrophic effects) is a therapeutic strategy intended to slow or halt the progression of neuronal loss, thus producing long-term benefits by favorably influencing outcome and preventing either the onset of disease or clinical decline. The present article: (i) reviews what has been learned regarding lithium's neurotrophic effects since Cade's original studies with this compound; (ii) presents human data supporting the presence of cellular atrophy and death in BD as well as neurotrophic effects associated with lithium in human studies; (iii) describes key direct targets of lithium involved in these neurotrophic effects, including neurotrophins, glycogen synthase kinase 3 (GSK-3), and mitochondrial/endoplasmic reticulum key proteins; and (iv) discusses lithium's neurotrophic effects in models of apoptosis and excitotoxicity as well as its potential neurotrophic effects in models of neurological disorders. Taken together, the evidence reviewed here suggests that lithium's neurotrophic effects in BD are an example of an old molecule acting as a new proof-of-concept agent. Continued work to decipher lithium's molecular actions will likely lead to the development of not only improved therapeutics for BD, but to neurotrophic enhancers that could prove useful in the treatment of many other illnesses.

Lithium chloride protects retinal neurocytes from nutrient deprivation by promoting DNA non-homologous end-joining

Lithium chloride is a therapeutic agent for treatment of bipolar affective disorders. Increasing numbers of studies have indicated that lithium has neuroprotective effects. However, the molecular mechanisms underlying the actions of lithium have not been fully elucidated. This study aimed to investigate whether lithium chloride produces neuroprotective function by improving DNA repair pathway in retinal neurocyte. In vitro, the primary cultured retinal neurocytes (85.7% are MAP-2 positive cells) were treated with lithium chloride, then cultured with serum-free media to simulate the nutrient deprived state resulting from ischemic insult. The neurite outgrowth of the cultured cells increased significantly in a dose-dependent manner when exposed to different levels of lithium chloride. Genomic DNA electrophoresis demonstrated greater DNA integrity of retinal neurocytes when treated with lithium chloride as compared to the control. Moreover, mRNA and protein levels of Ligase IV (involved in DNA non-homologous end-joining (NHEJ) pathway) in retinal neurocytes increased with lithium chloride. The end joining activity assay was performed to determine the role of lithium on NHEJ in the presence of extract from retinal neurocytes. The rejoining levels in retinal neurocytes treated with lithium were significantly increased as compared to the control. Furthermore, XRCC4, the Ligase IV partner, and the transcriptional factor, CREB and CTCF, were up-regulated in retinal cells after treating with 1.0mM lithium chloride. Therefore, our data suggest that lithium chloride protects the retinal neural cells from nutrient deprivation in vitro, which may be similar to the mechanism of cell death in glaucoma. The improvement in DNA repair pathway involving in Ligase IV might have an important role in lithium neuroprotection. This study provides new insights into the neural protective mechanisms of lithium chloride.