A differential impact of lithium on endothelium-dependent but not on endothelium-independent vessel relaxation

New Advances in the Pharmacology and Toxicology of Lithium: A Neurobiologically Oriented Overview

Over the last six decades, lithium has been considered the gold standard treatment for the long-term management of bipolar disorder due to its efficacy in preventing both manic and depressive episodes as well as suicidal behaviors. Nevertheless, despite numerous observed effects on various cellular pathways and biologic systems, the precise mechanism through which lithium stabilizes mood remains elusive. Furthermore, there is recent support for the therapeutic potential of lithium in other brain diseases. This review offers a comprehensive examination of contemporary understanding and predominant theories concerning the diverse mechanisms underlying lithium's effects. These findings are based on investigations utilizing cellular and animal models of neurodegenerative and psychiatric disorders. Recent studies have provided additional support for the significance of glycogen synthase kinase-3 (GSK3) inhibition as a crucial mechanism. Furthermore, research has shed more light on the interconnections between GSK3-mediated neuroprotective, antioxidant, and neuroplasticity processes. Moreover, recent advancements in animal and human models have provided valuable insights into how lithium-induced modifications at the homeostatic synaptic plasticity level may play a pivotal role in its clinical effectiveness. We focused on findings from translational studies suggesting that lithium may interface with microRNA expression. Finally, we are exploring the repurposing potential of lithium beyond bipolar disorder. These recent findings on the therapeutic mechanisms of lithium have provided important clues toward developing predictive models of response to lithium treatment and identifying new biologic targets. SIGNIFICANCE STATEMENT: Lithium is the drug of choice for the treatment of bipolar disorder, but its mechanism of action in stabilizing mood remains elusive. This review presents the latest evidence on lithium's various mechanisms of action. Recent evidence has strengthened glycogen synthase kinase-3 (GSK3) inhibition, changes at the level of homeostatic synaptic plasticity, and regulation of microRNA expression as key mechanisms, providing an intriguing perspective that may help bridge the mechanistic gap between molecular functions and its clinical efficacy as a mood stabilizer.

Blood and Brain Metabolites after Cerebral Ischemia

The study of an organism's response to cerebral ischemia at different levels is essential to understanding the mechanism of the injury and protection. A great interest is devoted to finding the links between quantitative metabolic changes and post-ischemic damage. This work aims to summarize the outcomes of the most studied metabolites in brain tissue-lactate, glutamine, GABA (4-aminobutyric acid), glutamate, and NAA (N-acetyl aspartate)-regarding their biological function in physiological conditions and their role after cerebral ischemia/reperfusion. We focused on ischemic damage and post-ischemic recovery in both experimental-including our results-as well as clinical studies. We discuss the role of blood glucose in view of the diverse impact of hyperglycemia, whether experimentally induced, caused by insulin resistance, or developed as a stress response to the cerebral ischemic event. Additionally, based on our and other studies, we analyze and critically discuss post-ischemic alterations in energy metabolites and the elevation of blood ketone bodies observed in the studies on rodents. To complete the schema, we discuss alterations in blood plasma circulating amino acids after cerebral ischemia. So far, no fundamental brain or blood metabolite(s) has been recognized as a relevant biological marker with the feasibility to determine the post-ischemic outcome or extent of ischemic damage. However, studies from our group on rats subjected to protective ischemic preconditioning showed that these animals did not develop post-ischemic hyperglycemia and manifested a decreased metabolic infringement and faster metabolomic recovery. The metabolomic approach is an additional tool for understanding damaging and/or restorative processes within the affected brain region reflected in the blood to uncover the response of the whole organism via interorgan metabolic communications to the stressful cerebral ischemic challenge.

Cerebrolysin in Patients with Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

Subarachnoid Hemorrhage (SAH) is one of the acute neurological conditions that is associated with high mortality and recovery failure rates. In recent years, due to the development of endovascular and classical techniques, the mortality rate after SAH has decreased. Currently, more research is focused on understanding the molecular mechanisms underlying SAH. Methods of treatment are investigated in order to obtain the best treatment result, not only survival. One of the drugs used in stroke, including SAH, is Cerebrolysin. It is a mixture of neuropeptides that has similar properties to neurotrophic factors. Its positive impact on strokes has been analyzed; however, there are no meta-analyses concerning only the subpopulation of patients diagnosed with SAH in the current literature. Therefore, we conducted a meta-analysis of available clinical trials to evaluate the effect of Cerebrolysin on the treatment outcome. The data suggest a positive effect of Cerebrolysin on the mortality of SAH patients. However, further randomized clinical trials with larger groups of patients are needed to draw final conclusions.

Arterial Stiffness in Patients with Bipolar Disorder

Objective

Bipolar disorder (BD) is an inflammatory and metabolic disease. The disease and the drugs used to treat it may affect cardiovascular disease (CVD) risk. The aim of this study is to investigate arterial stiffness in patients with BD and compare them with healthy controls.

Methods

Thirty-nine patients with BD type I in remission and 39 healthy control subjects were included in the study. Carotid and femoral artery intima-media thickness (IMT) and arterial thickness parameters were measured by Doppler ultrasonography.

Results

The elastic modulus value of the carotid artery was significantly higher in the patients than in the control group (p = 0.015). Although the IMT of both carotid and femoral artery was thicker in patients than in healthy control subjects, this difference was not statistically significant (p = 0.105; p = 0.391). There was a significant positive correlation between chlorpromazine equivalent dose and femoral elastic modulus value (p = 0.021, r = 0.539). There was a positive correlation between lithium equivalent dose and carotid compliance; a significant negative correlation between lithium equivalent dose and carotid elastic modulus was also determined (both p = 0.007, r = 0.466; p = 0.027, r = -0.391, respectively). No predictor was observed between drug dose and arterial stiffness parameters.

Conclusion

Arterial stiffness might be investigated for its potential to reduce CVD risk in patients with BD. Given the established CVD complications in this patient population, further studies are needed to determine whether the results are specific to antipsychotic treatment or BD and to clarify the potential arterial protective effects of mood stabilizers.

Tocotrienol-Rich Fraction Ameliorates the Aluminium Chloride-Induced Neurovascular Dysfunction-Associated Vascular Dementia in Rats

Neurovascular dysfunction leads to the second most common type of dementia, i.e., vascular dementia (VaD). Toxic metals, such as aluminium, increase the risk of neurovascular dysfunction-associated VaD. Hence, we hypothesized that a natural antioxidant derived from palm oil, i.e., tocotrienol-rich fraction (TRF), can attenuate the aluminium chloride (AlCl₃)-induced VaD in rats. Rats were induced with AlCl₃ (150 mg/kg) intraperitoneally for seven days followed by TRF treatment for twenty-one days. The elevated plus maze test was performed for memory assessment. Serum nitrite and plasma myeloperoxidase (MPO) levels were measured as biomarkers for endothelial dysfunction and small vessel disease determination. Thiobarbituric acid reactive substance (TBARS) was determined as brain oxidative stress marker. Platelet-derived growth factor-C (PDGF-C) expression in the hippocampus was identified using immunohistochemistry for detecting the neovascularisation process. AlCl₃ showed a significant decrease in memory and serum nitrite levels, while MPO and TBARS levels were increased; moreover, PDGF-C was not expressed in the hippocampus. However, TRF treatment significantly improved memory, increased serum nitrite, decreased MPO and TBARS, and expressed PDGF-C in hippocampus. Thus, the results imply that TRF reduces brain oxidative stress, improves endothelial function, facilitates hippocampus PDGF-C expression for neovascularisation process, protects neurons, and improves memory in neurovascular dysfunction-associated VaD rats.

Beyond its Psychiatric Use: The Benefits of Low-dose Lithium Supplementation

Lithium is most well-known for its mood-stabilizing effects in the treatment of bipolar disorder. Due to its narrow therapeutic window (0.5-1.2 mM serum concentration), there is a stigma associated with lithium treatment and the adverse effects that can occur at therapeutic doses. However, several studies have indicated that doses of lithium under the predetermined therapeutic dose used in bipolar disorder treatment may have beneficial effects not only in the brain but across the body. Currently, literature shows that low-dose lithium (≤0.5 mM) may be beneficial for cardiovascular, musculoskeletal, metabolic, and cognitive function, as well as inflammatory and antioxidant processes of the aging body. There is also some evidence of low-dose lithium exerting a similar and sometimes synergistic effect on these systems. This review summarizes these findings with a focus on low-dose lithium's potential benefits on the aging process and age-related diseases of these systems, such as cardiovascular disease, osteoporosis, sarcopenia, obesity and type 2 diabetes, Alzheimer's disease, and the chronic low-grade inflammatory state known as inflammaging. Although lithium's actions have been widely studied in the brain, the study of the potential benefits of lithium, particularly at a low dose, is still relatively novel. Therefore, this review aims to provide possible mechanistic insights for future research in this field.

MicroRNA-223 Attenuates Stretch-Injury-Induced Apoptosis in Brain Microvascular Endothelial Cells by Regulating RhoB Expression

MiR-223 is a miRNA with important functions in apoptosis, carcinogenesis, and inflammation, and it was demonstrated to be over-expressed in brain tissue after traumatic brain injury (TBI). However, few studies have focused on its role in protecting brain microvascular endothelial cells (BMECs). This study evaluated the protective effect of miR-223 on BMECs after stretch injury (SI). bEnd.3 cells (BMECs of mouse) were transfected with overexpressing and blocking lentivirus of miR-223, then were subjected to SI. After immunofluorescence assay, it was demonstrated that miR-223 overexpression significantly rescued the SI-induced loss of ZO-1 (Zonula Occludens 1, tight junction protein) (p < 0.01), while miR-223 blocking exacerbated the loss of ZO-1 (p < 0.05). Flow cytometry confirmed a significant increase in the proportion of apoptotic bEnd.3 cells after SI, and miR-223 overexpression reduced this proportion (p < 0.001). The result of Western blot revealed that miR-223 overexpression significantly reduced the expression of cleaved caspase-3 (cl-caspase 3) (p < 0.05) and RhoB (p < 0.01), while miR-223 blocking increased the expression of these proteins (p < 0.05, p < 0.001). Additionally, knockdown of RhoB significantly reduced the expression of cl-caspase 3 (p < 0.001). These findings suggested that miR-223 can alleviate SI-induced apoptosis of BMECs, and this anti-apoptotic effect is at least partially achieved by inhibiting the expression of RhoB. Moreover, miR-223 may play a role in maintaining the integrity of BBB during TBI.

Electroacupuncture improves TBI dysfunction by targeting HDAC overexpression and BDNF-associated Akt/GSK-3β signaling

Background

Acupuncture or electroacupuncture (EA) appears to be a potential treatment in acute clinical traumatic brain injury (TBI); however, it remains uncertain whether acupuncture affects post-TBI histone deacetylase (HDAC) expression or impacts other biochemical/neurobiological events.

Materials and methods

We used behavioral testing, Western blot, and immunohistochemistry analysis to evaluate the cellular and molecular effects of EA at LI4 and LI11 in both weight drop-impact acceleration (WD)- and controlled cortical impact (CCI)-induced TBI models.

Results

Both WD- and CCI-induced TBI caused behavioral dysfunction, increased cortical levels of HDAC1 and HDAC3 isoforms, activated microglia and astrocytes, and decreased cortical levels of BDNF as well as its downstream mediators phosphorylated-Akt and phosphorylated-GSK-3β. Application of EA reversed motor, sensorimotor, and learning/memory deficits. EA also restored overexpression of HDAC1 and HDAC3, and recovered downregulation of BDNF-associated signaling in the cortex of TBI mice.

Conclusion

The results strongly suggest that acupuncture has multiple benefits against TBI-associated adverse behavioral and biochemical effects and that the underlying mechanisms are likely mediated by targeting HDAC overexpression and aberrant BDNF-associated Akt/GSK-3 signaling.

Phosphorylation of PI3K/Akt at Thr308, but not MAPK kinase, mediates lithium-induced neuroprotection against cerebral ischemia in mice

Lithium, in addition to its effect on acute and long-term bipolar disorder, is involved in neuroprotection after ischemic stroke. Yet, its mechanism of action is still poorly understood, which was only limited to its modulatory effect on GSK pathway. Therefore, we initially analyzed the dose-dependent effects of lithium on neurological deficits, infarct volume, brain edema and blood-brain barrier integrity, along with neuronal injury and survival in mice subjected to focal cerebral ischemia. Thereafter, we investigated the involvement of the PI3K/Akt and MEK signal transduction pathways and their components. Our observations revealed that 2 mmol/kg lithium significantly improved post-ischemic brain tissue survival. Although, 2 mmol/kg lithium had no negative effect on brain microcirculation, 5 and 20 mmol/kg lithium reduced brain perfusion. Furthermore, supratherapeutic dose of lithium in 20 mmol/kg lead to animal death. In addition, improvement of brain perfusion with L-arginine, did not change the effect of 5 mmol/kg lithium on brain injury. Additionally, post-stroke blood-brain barrier leakage, hemodynamic impairment and apoptosis have been reversed by lithium treatment. Interestingly, lithium-induced neuroprotection was associated with increased phosphorylation of Akt at Thr308 and suppressed GSK-3β phosphorylation at Ser9 residue. Lithium upregulated Erk-2 and downregulated JNK-2 phosphorylation. To distinguish whether neuroprotective effects of lithium are modulated by PI3K/Akt or MEK, we sequentially blocked these pathways and demonstrated that the neuroprotective activity of lithium persisted during MEK/ERK inhibition, whereas PI3K/Akt inhibition abolished neuroprotection. Collectively, we demonstrated lithium exerts its post-stroke neuroprotective activity via the PI3K/Akt pathway, specifically via Akt phosphorylation at Thr308, but not via MEK/ERK.

Lithium and Erectile Dysfunction: An Overview

Lithium has been a mainstay of therapy for patients with bipolar disorders for several decades. However, it may exert a variety of adverse effects that can affect patients' compliance. Sexual and erectile dysfunction has been reported in several studies by patients who take lithium as monotherapy or combined with other psychotherapeutic agents. The exact mechanisms underlying such side effects of lithium are not completely understood. It seems that both central and peripheral mechanisms are involved in the lithium-related sexual dysfunction. Here, we had an overview of the epidemiology of lithium-related sexual and erectile dysfunction in previous clinical studies as well as possible pathologic pathways that could be involved in this adverse effect of lithium based on the previous preclinical studies. Understanding such mechanisms could potentially open a new avenue for therapies that can overcome lithium-related sexual dysfunction and improve patients' adherence to the medication intake.

Over-Dose Lithium Toxicity as an Occlusive-like Syndrome in Rats and Gastric Pentadecapeptide BPC 157

Due to endothelial impairment, high-dose lithium may produce an occlusive-like syndrome, comparable to permanent occlusion of major vessel-induced syndromes in rats; intracranial, portal, and caval hypertension, and aortal hypotension; multi-organ dysfunction syndrome; brain, heart, lung, liver, kidney, and gastrointestinal lesions; arterial and venous thrombosis; and tissue oxidative stress. Stable gastric pentadecapeptide BPC 157 may be a means of therapy via activating loops (bypassing vessel occlusion) and counteracting major occlusion syndromes. Recently, BPC 157 counteracted the lithium sulfate regimen in rats (500 mg/kg/day, ip, for 3 days, with assessment at 210 min after each administration of lithium) and its severe syndrome (muscular weakness and prostration, reduced muscle fibers, myocardial infarction, and edema of various brain areas). Subsequently, BPC 157 also counteracted the lithium-induced occlusive-like syndrome; rapidly counteracted brain swelling and intracranial (superior sagittal sinus) hypertension, portal hypertension, and aortal hypotension, which otherwise would persist; counteracted vessel failure; abrogated congestion of the inferior caval and superior mesenteric veins; reversed azygos vein failure; and mitigated thrombosis (superior mesenteric vein and artery), congestion of the stomach, and major hemorrhagic lesions. Both regimens of BPC 157 administration also counteracted the previously described muscular weakness and prostration (as shown in microscopic and ECG recordings), myocardial congestion and infarction, in addition to edema and lesions in various brain areas; marked dilatation and central venous congestion in the liver; large areas of congestion and hemorrhage in the lung; and degeneration of proximal and distal tubules with cytoplasmic vacuolization in the kidney, attenuating oxidative stress. Thus, BPC 157 therapy overwhelmed high-dose lithium intoxication in rats.

Mechanism of Endoplasmic Reticulum Stress in Cerebral Ischemia

Endoplasmic reticulum (ER) is the main organelle for protein synthesis, trafficking and maintaining intracellular Ca²⁺ homeostasis. The stress response of ER results from the disruption of ER homeostasis in neurological disorders. Among these disorders, cerebral ischemia is a prevalent reason of death and disability in the world. ER stress stemed from ischemic injury initiates unfolded protein response (UPR) regarded as a protection mechanism. Important, disruption of Ca²⁺ homeostasis resulted from cytosolic Ca²⁺ overload and depletion of Ca²⁺ in the lumen of the ER could be a trigger of ER stress and the misfolded protein synthesis. Brain cells including neurons, glial cells and endothelial cells are involved in the complex pathophysiology of ischemic stroke. This is generally important for protein underfolding, but even more for cytosolic Ca²⁺ overload. Mild ER stress promotes cells to break away from danger signals and enter the adaptive procedure with the activation of pro-survival mechanism to rescue ischemic injury, while chronic ER stress generally serves as a detrimental role on nerve cells via triggering diverse pro-apoptotic mechanism. What’s more, the determination of some proteins in UPR during cerebral ischemia to cell fate may have two diametrically opposed results which involves in a specialized set of inflammatory and apoptotic signaling pathways. A reasonable understanding and exploration of the underlying molecular mechanism related to ER stress and cerebral ischemia is a prerequisite for a major breakthrough in stroke treatment in the future. This review focuses on recent findings of the ER stress as well as the progress research of mechanism in ischemic stroke prognosis provide a new treatment idea for recovery of cerebral ischemia.

Oxidative Stress and the Neurovascular Unit

The neurovascular unit (NVU) is a relatively recent concept that clearly describes the relationship between brain cells and their blood vessels. The components of the NVU, comprising different types of cells, are so interrelated and associated with each other that they are considered as a single functioning unit. For this reason, even slight disturbances in the NVU could severely affect brain homeostasis and health. In this review, we aim to describe the current state of knowledge concerning the role of oxidative stress on the neurovascular unit and the role of a single cell type in the NVU crosstalk.

The association between accelerated vascular aging and cyclothymic affective temperament in women

OBJECTIVE

Affective temperaments (depressive, anxious, irritable, hyperthymic, cyclothymic) are regarded as the biologically stable core of personality. Accumulating data suggest their relationship with cardiovascular diseases. However, there are currently limited data on the association of affective temperaments and accelerated vascular aging. The aim of our study was to evaluate the relationship between affective temperaments and vascular age, as assessed by coronary artery calcium scoring (CACS).

METHODS

In our cross-sectional study, 209 consecutive patients referred to coronary computed tomography angiography (CCTA) due to suspected coronary artery disease (CAD) were included. All patients completed the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A) and the Beck Depression Inventory (BDI). Vascular age was estimated using CACS and its difference from chronological age for each patient was calculated. Linear regression analysis was used to identify predictors of accelerated vascular aging in the entire cohort and in male and female sub-populations.

RESULTS

Besides traditional risk factors, cyclothymic temperament score proved to be an independent predictor of accelerated vascular aging in women (β = 0.89 [95%CI: 0.04-1.75]), while this association was absent in men.

CONCLUSIONS

Our results suggest that cyclothymic affective temperament is associated with accelerated vascular aging in women. Assessment of affective temperaments may potentiate more precise cardiovascular risk stratification of patients.

The role of brain barriers in the neurokinetics and pharmacodynamics of lithium

Lithium (Li) is the most widely used mood stabilizer in treating patients with bipolar disorder. However, more than half of the patients do not or partially respond to Li therapy, despite serum Li concentrations in the serum therapeutic range. The exact mechanisms underlying the pharmacokinetic-pharmacodynamic (PK-PD) relationships of lithium are still poorly understood and alteration in the brain pharmacokinetics of lithium may be one of the mechanisms explaining the variability in the clinical response to Li. Brain barriers such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) play a crucial role in controlling blood-to-brain and brain-to-blood exchanges of various molecules including central nervous system (CNS) drugs. Recent in vivo studies by nuclear resonance spectroscopy revealed heterogenous brain distribution of Li in human that were not always correlated with serum concentrations, suggesting regional and variable transport mechanisms of Li through the brain barriers. Moreover, alteration in the functionality and integrity of brain barriers is reported in various CNS diseases, as a cause or a consequence and in this regard, Li by itself is known to modulate BBB properties such as the expression and activity of various transporters, metabolizing enzymes, and the specialized tight junction proteins on BBB. In this review, we will focus on recent knowledge into the role of the brain barriers as key-element in the Li neuropharmacokinetics which might improve the understanding of PK-PD of Li and its interindividual variability in drug response.

Lithium beyond psychiatric indications: the reincarnation of a new old drug

Lithium has been used in the treatment of bipolar disorders for decades, but the exact mechanisms of action remain elusive to this day. Recent evidence suggests that lithium is critically involved in a variety of signaling pathways affecting apoptosis, inflammation, and neurogenesis, all of which contributing to the complex pathophysiology of various neurological diseases. As a matter of fact, preclinical work reports both acute and long-term neuroprotection in distinct neurological disease models such as Parkinson’s disease, traumatic brain injury, Alzheimer’s disease, and ischemic stroke. Lithium treatment reduces cell injury, decreases α-synuclein aggregation and Tau protein phosphorylation, modulates inflammation and even stimulates neuroregeneration under experimental conditions of Parkinson’s disease, traumatic brain injury, and Alzheimer’s disease. The therapeutic impact of lithium under conditions of ischemic stroke was also studied in numerous preclinical in vitro and in vivo studies, giving rise to a randomized double-blind clinical stroke trial. The preclinic data revealed a lithium-induced upregulation of anti-apoptotic proteins such as B-cell lymphoma 2, heat shock protein 70, and activated protein 1, resulting in decreased neuronal cell loss. Lithium, however, does not only yield postischemic neuroprotection but also enhances endogenous neuroregeneration by stimulating neural stem cell proliferation and by regulating distinct signaling pathways such as the RE1-silencing transcription factor. In line with this, lithium treatment has been shown to modulate postischemic cytokine secretion patterns, diminishing microglial activation and stabilizing blood-brain barrier integrity yielding reduced levels of neuroinflammation. The aforementioned observations culminated in a first clinical trial, which revealed an improved motor recovery in patients with cortical stroke after lithium treatment. Beside its well-known psychiatric indications, lithium is thus a promising neuroprotective candidate for the aforementioned neurological diseases. A detailed understanding of the lithium-induced mechanisms, however, is important for prospective clinical trials which may pave the way for a successful bench-to-bedside translation in the future. In this review, we will give an overview of lithium-induced neuroprotective mechanisms under various pathological conditions, with special emphasis on ischemic stroke.

Lithium enhances post-stroke blood-brain barrier integrity, activates the MAPK/ERK1/2 pathway and alters immune cell migration in mice

Lithium induces neuroprotection against cerebral ischemia, although the underlying mechanisms remain elusive. We have previously suggested a role for lithium in calcium regulation and (extra)cerebral vessel relaxation under non-ischemic conditions. Herein, we aimed to investigate whether or not lithium contributes to post-stroke stabilization of the blood-brain barrier (BBB) in mice. Using an oxygen-glucose-deprivation (OGD) model, we first analyzed the impact of lithium treatment on endothelial cells (EC) in vitro. Indeed, such treatment of EC exposed to OGD resulted in increased cell survival as well as in enhanced expression of tight junction proteins and P-glycoprotein. Additional in vivo studies demonstrated an increased stabilization of the BBB upon lithium treatment in stroke mice, as shown by a reduced Evans blue extravasation and an elevation of tight junction protein expression. Furthermore, stabilization of the BBB as a consequence of lithium treatment was associated with an inhibition of matrix metalloproteinase-9 activity, independent of calveolin-1 regulation. In line with this, flow cytometry analysis revealed that lithium treatment led to a decreased neutrophil invasion and an increased T cell extravasation from the blood compartment towards the brain parenchyma. We finally identified the pro-survival MAPK/ERK1/2 pathway as the key regulator of the impact of lithium on the BBB. In conclusion, we demonstrate for the first time that lithium is able to enhance post-stroke BBB integrity. Importantly, our work delivers novel insights into the exact mechanism of lithium-induced acute neuroprotection, providing critical information for future clinical trials involving lithium treatment in stroke patients.

Investigation of the impact of an ADCY2 polymorphism as a predictive biomarker in bipolar disorder, suicide tendency and response to lithium carbonate therapy: the first report from Iran

High rates of mortality due to both suicide and medical comorbidities in bipolar patients can be decreased through the administration of lithium, which affects the cerebral endothelium as well as neurons. To investigate the role of ADCY2 in risk of bipolar disorder, we genotyped the ADCY2 rs2290910 in bipolar patients and healthy controls using amplification refractory mutation system PCR. This polymorphism was associated with risk of bipolar disorder (odds ratio [OR]: 0.430; 95% CI: 0.296-0.624; p = 0.001). The C allele was more frequent in suicide ideation group compared other groups (OR: 2.7; 95% CI: 1.386-5.302; p = 0.004). The T allele was more frequent in suicide attempt group compared with suicide ideation group (OR: 0.238; 95% CI: 0.111-0.509; p = 0.001).

Lithium treatment mitigates white matter injury after intracerebral hemorrhage through brain-derived neurotrophic factor signaling in mice

Intracerebral hemorrhage (ICH), a subtype of stroke with high morbidity and mortality, occurs mainly in the basal ganglia and causes white matter injury (WMI), resulting in severe motor dysfunction and poor prognosis in patients. The preservation of the white matter around the hematoma is crucial for motor function recovery, but there is currently no effective treatment for WMI following ICH. Lithium has been widely used for the treatment of bipolar disorder for decades. Although the protective effects of lithium on neurodegenerative diseases and cerebral trauma have been studied in recent years, whether it can be used to alleviate WMI after ICH remains to be researched. The results of this study revealed that ICH caused significant functional and pathological abnormalities in mice. After LiCl was administered to mice with ICH, behavioural performance and electrophysiological functions were improved and ICH-induced white matter pathological injury, including myelin sheath and axonal degeneration, was ameliorated. Furthermore, LiCl treatment decreased the death of mature oligodendrocytes (OLGs) in ICH mice, which may have been attributed to the enhanced expression of brain-derived neurotrophic factor (BDNF) regulated by the LiCl-induced inhibition of glycogen synthase kinase-3β (GSK-3β). The decreased death of OLGs was closely associated with decreased destruction of the myelin sheath and alleviated degradation of the axons. In summary, this study suggests that the protective effect of lithium on WMI after ICH might be related to an increased level of BDNF and that LiCl treatment may be a potential therapeutic method to palliate WMI after ICH.

Impact of Mood on Endothelial Function and Arterial Stiffness in Bipolar Disorder

Background

Previous research in bipolar disorder demonstrates greater than expected vascular dysfunction later in the course of illness, proportionate to the cumulative burden of mood symptoms. However, little is known about the effect of acute mood states on vascular function. Here we examine the relation between vascular function and mood state in individuals with bipolar disorder.

Method

This prospective study followed 40 individuals with bipolar disorder for up to 6 months. Participants were assessed for mood state and vascular function at baseline, 2 weeks, and 6 months. Mood state was determined using clinician-administered Montgomery-Åsberg Depression Rating Scale and Young Mania Rating Scale. Vascular function was assessed by flow-mediated dilation (FMD) of the brachial artery, forearm vascular resistance (FVR), and arterial stiffness.

Results

Participants had a mean age of 30.1 years and 75% were male. Primary outcome measures FMD and nitroglycerine-mediated dilation were not found to have statistically significant associations with depressive or manic symptoms. In unadjusted models, higher manic symptoms were significantly associated with increased FVR nitroprusside-mediated dilation and diastolic blood pressure. In adjusted models, higher depressive symptoms were significantly associated with increases in augmentation index adjusted for heart rate of 75 bpm, and higher manic symptoms remained associated with increases in diastolic blood pressure.

Conclusion

FMD may have limited sensitivity as a biomarker for measuring short-term effects of mood state. Longer-term prospective studies are needed to clarify the temporal relation between chronic mood symptoms and vascular function in bipolar disorder.

Complex Clearance Mechanisms After Intraventricular Hemorrhage and rt-PA Treatment-a Review on Clinical Trials

Intracerebral hemorrhage in combination with intraventricular hemorrhage (IVH) is a severe type of stroke frequently leading to prolonged clinical care, continuous disability, shunt dependency, and high mortality. The molecular mechanisms induced by IVH are complex and not fully understood. Moreover, the treatment options for IVH are limited. Intraventricular recombinant tissue plasminogen activator (rt-PA) dissolves the blood clot in the ventricular system; however, whether the clinical outcome is thereby positively affected is still being debated. The mechanistic cascade induced by intraventricular rt-PA therapy may cure and harm in parallel. Despite the fact that intraventricular blood clots are thereby dissolved, blood derivatives enter the parenchyma and may still adversely affect functional structures of the brain: Smaller blood clots may obstruct the perivascular (Virchow-Robin) space and thereby the glymphatic system with detrimental consequences for cerebrospinal fluid (CSF)/interstitial fluid (ISF) flow. These clots, blood cells but also blood derivatives in the perivascular space, destabilize the blood-brain barrier from the brain parenchyma side, thereby also functionally weakening the neurovascular unit. This may lead to further accommodation of serum proteins in the ISF and particularly in the perivascular space further contributing to the adverse effects on the neuronal microenvironment. Finally, the arterial (Pacchionian) granulations have to cope with ISF containing this "blood, cell, and protein cocktail," resulting in obstruction and insufficient function of the arterial granulations, followed by a malresorptive hydrocephalus. Particularly in light of currently improved knowledge on the physiologic and pathophysiologic clearance of cerebrospinal fluid and interstitial fluid, a critical discussion and reevaluation of our current therapeutic strategies to treat intraventricular hemorrhages are needed to successfully treat patients suffering from this severe type of stroke. In this review, we therefore summarize and discuss recent clinical trials and future directions for the field of IVH with respect to the currently increased understanding of the glymphatic system and the neurovascular unit pathophysiology.

Endogenous acetylcholine regulates neuronal and astrocytic vascular endothelial growth factor expression levels via different acetylcholine receptor mechanisms

Vascular endothelial growth factor (VEGF), a signaling molecule involved in angiogenesis, plays an important role in neuroprotection and neurogenesis. In the present study, we aimed to elucidate the mechanisms underlying endogenous acetylcholine (ACh)-induced VEGF expression in neurons and astrocytes, and identify the neuronal cells contributing to its expression in the medial septal area, a nuclear origin of cholinergic neurons mainly projecting to the hippocampus. The mRNA expression and secretion of VEGF were measured by RT-PCR and ELISA using mouse primary cultured cortical neurons and astrocytes. VEGF expression in the medial septal area was assessed by RT-PCR and immunostaining using mice treated with tacrine [9-amino-1,2,3,4-tetrahydro-acridine HCl (THA); 2.5 mg/kg, i.p.] once daily for 7 days. The THA treatment increased VEGF mRNA expression in neurons in a manner that was reversed by mecamylamine, a nicotinic ACh receptor (AChR) antagonist, whereas in mouse primary cultured astrocytes, carbachol, but not THA dose-dependently increased VEGF mRNA expression and secretion in a manner that was inhibited by scopolamine, a muscarinic AChR inhibitor. In in vivo studies, the administration of THA significantly increased the expression of VEGF in medial septal cholinergic neurons and the effects of THA were significantly blocked by mecamylamine. THA also significantly increased the expression levels of a phosphorylated form of VEGF receptor 2 (p-VEGFR2), an activated form of VEGFR2. The present results suggest that endogenous ACh plays an up-regulatory role for VEGF expression in neurons and astrocytes via different mechanisms. Moreover, endogenous ACh-induced increases in VEGF levels appear to activate VEGFR2 on medial septal cholinergic neurons via an autocrine mechanism.

Low-Dose Lithium Stabilizes Human Endothelial Barrier by Decreasing MLC Phosphorylation and Universally Augments Cholinergic Vasorelaxation Capacity in a Direct Manner

Lithium at serum concentrations up to 1 mmol/L has been used in patients suffering from bipolar disorder for decades and has recently been shown to reduce the risk for ischemic stroke in these patients. The risk for stroke and thromboembolism depend not only on cerebral but also on general endothelial function and health; the entire endothelium as an organ is therefore pathophysiologically relevant. Regardless, the knowledge about the direct impact of lithium on endothelial function remains poor. We conducted an experimental study using lithium as pharmacologic pretreatment for murine, porcine and human vascular endothelium. We predominantly investigated endothelial vasorelaxation capacities in addition to human basal and dynamic (thrombin-/PAR-1 receptor agonist-impaired) barrier functioning including myosin light chain (MLC) phosphorylation (MLC-P). Low-dose therapeutic lithium concentrations (0.4 mmol/L) significantly augment the cholinergic endothelium-dependent vasorelaxation capacities of cerebral and thoracic arteries, independently of central and autonomic nerve system influences. Similar concentrations of lithium (0.2–0.4 mmol/L) significantly stabilized the dynamic thrombin-induced and PAR-1 receptor agonist-induced permeability of human endothelium, while even the basal permeability appeared to be stabilized. The lithium-attenuated dynamic permeability was mediated by a reduced endothelial MLC-P known to be followed by a lessening of endothelial cell contraction and paracellular gap formation. The well-known lithium-associated inhibition of inositol monophosphatase/glycogen synthase kinase-3-β signaling-pathways involving intracellular calcium concentrations in neurons seems to similarly occur in endothelial cells, too, but with different down-stream effects such as MLC-P reduction. This is the first study discovering low-dose lithium as a drug directly stabilizing human endothelium and ubiquitously augmenting cholinergic endothelium-mediated vasorelaxation. Our findings have translational and potentially clinical impact on cardiovascular and cerebrovascular disease associated with inflammation explaining why lithium can reduce, e.g., the risk for stroke. However, further clinical studies are warranted.