Association between lithium use and the incidence of dementia and its subtypes: A retrospective cohort study

Intracellular effects of lithium in aging neurons

Lithium therapy received approval during the 1970s, and it has been used for its antidepressant, antimanic, and anti-suicidal effects for acute and long-term prophylaxis and treatment of bipolar disorder (BPD). These properties have been well established; however, the molecular and cellular mechanisms remain controversial. In the past few years, many studies demonstrated that at the cellular level, lithium acts as a regulator of neurogenesis, aging, and Ca2+ homeostasis. At the molecular level, lithium modulates aging by inhibiting glycogen synthase kinase-3β (GSK-3β), and the phosphatidylinositol (PI) cycle; latter, lithium specifically inhibits inositol production, acting as a non-competitive inhibitor of inositol monophosphatase (IMPase). Mitochondria and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) have been related to lithium activity, and its regulation is mediated by GSK-3β degradation and inhibition. Lithium also impacts Ca2+ homeostasis in the mitochondria modulating the function of the lithium-permeable mitochondrial Na+-Ca2+exchanger (NCLX), affecting Ca2+ efflux from the mitochondrial matrix to the endoplasmic reticulum (ER). A close relationship between the protease Omi, GSK-3β, and PGC-1α has also been established. The purpose of this review is to summarize some of the intracellular mechanisms related to lithium activity and how, through them, neuronal aging could be controlled.

Lithium Exposure and Risk of Major Neurocognitive Disorders: A Systematic Review and Meta-analysis

BACKGROUND

Published studies on the association between lithium use and the decreased risk of major neurocognitive disorders (MNCDs) have shown disparities in their conclusions. We aimed to provide updated evidence of this association.

METHODS

A comprehensive literature search was performed in PubMed, EMBASE, and Cochrane Library from inception until August 31, 2023. All the observational studies evaluating the association between lithium use and MNCD risk were eligible for inclusion. Pooled odds ratios (ORs) and 95% prediction intervals were computed using random-effects models.

RESULTS

Eight studies with 377,060 subjects were included in the analysis. In the general population on the association between lithium use versus nonuse and dementia, the OR was 0.94 (95% confidence interval [CI] = 0.77-1.24). Further analysis also demonstrated that lithium use was not associated with an increased risk of Alzheimer's disease (OR = 0.69, 95% CI: 0.31-1.65). When the analysis was restricted to individuals with bipolar disorder to reduce the confounding by clinical indication, lithium exposure was also not associated with a decreased risk of MNCD (OR = 0.9, 95% CI = 0.71-1.15).

CONCLUSION

The results of this systematic review and meta-analysis do not support a significant association between lithium use and the risk of MNCD.

GSK3: A potential target and pending issues for treatment of Alzheimer's disease

Glycogen synthase kinase-3 (GSK3), consisting of GSK3α and GSK3β subtypes, is a complex protein kinase that regulates numerous substrates. Research has observed increased GSK3 expression in the brains of Alzheimer's disease (AD) patients and models. AD is a neurodegenerative disorder with diverse pathogenesis and notable cognitive impairments, characterized by Aβ aggregation and excessive tau phosphorylation. This article provides an overview of GSK3's structure and regulation, extensively analyzing its relationship with AD factors. GSK3 overactivation disrupts neural growth, development, and function. It directly promotes tau phosphorylation, regulates amyloid precursor protein (APP) cleavage, leading to Aβ formation, and directly or indirectly triggers neuroinflammation and oxidative damage. We also summarize preclinical research highlighting the inhibition of GSK3 activity as a primary therapeutic approach for AD. Finally, pending issues like the lack of highly specific and affinity-driven GSK3 inhibitors, are raised and expected to be addressed in future research. In conclusion, GSK3 represents a target in AD treatment, filled with hope, challenges, opportunities, and obstacles.

Temporal trends in population attributable fractions of modifiable risk factors for dementia: a time-series study of the English Longitudinal Study of Ageing (2004-2019)

BACKGROUND

Interest in modifiable risk factors (MRFs) for dementia is high, given the personal, social, and economic impact of the disorder, especially in ageing societies such as the United Kingdom. Exploring the population attributable fraction (PAF) of dementia attributable to MRFs and how this may have changed over time remains unclear. Unravelling the temporal dynamics of MRFs is crucial for informing the development of evidence-based and effective public health policies. This investigation examined the temporal trajectories of MRFs for dementia in England.

METHODS

We used data from the English Longitudinal Study of Ageing, a panel study over eight waves collected between 2004 and 2019 (76,904 interviews in total). We calculated the PAFs for twelve MRFs (including six early- to mid-life factors and six late-life factors), as recommended by the Lancet Commission, and the individual weighted PAFs (IW-PAFs) for each risk factor. Temporal trends were analysed to understand the changes in the overall PAF and IW-PAF over the study period. Subgroup analyses were conducted by sex and socioeconomic status (SES).

RESULTS

The overall PAF for dementia MRFs changed from 46.73% in 2004/2005 to 36.79% in 2018/2019, though this trend was not statistically significant. During 2004-2019, hypertension, with an average IW-PAF of 8.21%, was the primary modifiable determinant of dementia, followed by obesity (6.16%), social isolation (5.61%), hearing loss (4.81%), depression (4.72%), low education (4.63%), physical inactivity (3.26%), diabetes mellitus (2.49%), smoking (2.0%), excessive alcohol consumption (1.16%), air pollution (0.42%), and traumatic brain injury (TBI) (0.26%). During 2004-2019, only IW-PAFs of low education, social isolation, and smoking showed significant decreasing trends, while IW-PAFs of other factors either did not change significantly or increased (including TBI, diabetes mellitus, and air pollution). Upon sex-specific disaggregation, a higher overall PAF for MRFs was found among women, predominantly associated with later-life risk factors, most notably social isolation, depression, and physical inactivity. Additionally, hearing loss, classified as an early- to mid-life factor, played a supplementary role in the identified sex disparity. A comparable discrepancy was evident upon PAF evaluation by SES, with lower income groups experiencing a higher dementia risk, largely tied to later-life factors such as social isolation, physical inactivity, depression, and smoking. Early- to mid-life factors, in particular, low education and obesity, were also observed to contribute to the SES-associated divergence in dementia risk. Temporal PAF and IW-PAF trends, stratified by sex and SES, revealed that MRF PAF gaps across sex or SES categories have persisted or increased.

CONCLUSIONS

In England, there was little change over time in the proportion of dementia attributable to known modifiable risk factors. The observed trends underscore the continuing relevance of these risk factors and the need for targeted public health strategies to address them.

Temporal trends and disparities of population attributable fractions of modifiable risk factors for dementia in China: a time-series study of the China health and retirement longitudinal study (2011-2018)

Background

In China, dementia poses a significant public health challenge, exacerbated by an ageing population and lifestyle changes. This study assesses the temporal trends and disparities in the population-attributable fractions (PAFs) of modifiable risk factors (MRFs) for new-onset dementia from 2011 to 2018.

Methods

We used data from the China Health and Retirement Longitudinal Study (CHARLS), covering 75,214 person-waves. We calculated PAFs for 12 MRFs identified by the Lancet Commission (including six early-to mid-life factors and six late-life factors). We also determined the individual weighted PAFs (IW-PAFs) for each risk factor. Subgroup analyses were conducted by sex, socio-economic status (SES), and geographic location.

Findings

The overall PAF for dementia MRFs had a slight increase from 45.36% in 2011 to 52.46% in 2018, yet this change wasn't statistically significant. During 2011-2018, the most contributing modifiable risk was low education (average IW-PAF 11.3%), followed by depression, hypertension, smoking, and physical inactivity. Over the eight-year period, IW-PAFs for risk factors like low education, hypertension, hearing loss, smoking, and air pollution showed decreasing trends, while others increased, but none of these changes were statistically significant. Sex-specific analysis revealed higher IW-PAFs for traumatic brain injury (TBI), social isolation, and depression in women, and for alcohol and smoking in men. The decline in IW-PAF for men's hearing loss were significant. Lower-income individuals had higher overall MRF PAFs, largely due to later-life factors like depression. Early-life factors, such as TBI and low education, also contributed to SES disparities. Rural areas reported higher overall MRF PAFs, driven by factors like depression, low education, and hearing loss. The study also found that the gap in MRF PAFs across different SES groups or regions either remained constant or increased over the study period.

Interpretation

The study reveals a slight but non-significant increase in dementia's MRF PAF in China, underscoring the persistent relevance of these risk factors. The findings highlight the need for targeted public health strategies, considering the demographic and regional differences, to effectively tackle and reduce dementia risk in China's diverse population.

Funding

This work was supported by the PKU Young Scholarship in Global Health and Development.

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.

Lithium Therapy's Potential to Lower Dementia Risk and the Prevalence of Alzheimer's Disease: A Meta-Analysis

INTRODUCTION

Dementia is a neurodegenerative disease with insidious onset and progressive progression, of which the most common type is Alzheimer's disease (AD). Lithium, a trace element in the body, has neuroprotective properties. However, whether lithium can treat dementia or AD remains a highly controversial topic. Therefore, we conducted a meta-analysis.

METHODS

A systematic literature review was conducted on PubMed, Embase, and Web of Science. Comparison of the effects of lithium on AD or dementia in terms of use, duration, and dosage, and meta-analysis to test whether lithium therapy is beneficial in ameliorating the onset of dementia or AD. Sensitivity analyses were performed using a stepwise exclusion method. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of included studies. We determined the relative risk (RR) between patient groups using a random-effects model.

RESULTS

A total of seven studies were included. The forest plot results showed that taking lithium therapy reduced the risk of AD (RR 0.59, 95% confidence interval [CI]: 0.44-0.78) and is also protective in reducing the risk of dementia (RR 0.66, 95% CI: 0.56-0.77). The duration of lithium therapy was able to affect dementia incidence (RR 0.70, 95% CI: 0.55-0.88); however, it is unclear how this effect might manifest in AD. It is also uncertain how many prescriptions for lithium treatment lower the chance of dementia development.

CONCLUSION

The duration of treatment and the usage of lithium therapy seem to lower the risk of AD and postpone the onset of dementia.

Microdose lithium improves behavioral deficits and modulates molecular mechanisms of memory formation in female SAMP-8, a mouse model of accelerated aging

Alzheimer's disease (AD) is the most common neuronal disorder that leads to the development of dementia. Until nowadays, some therapies may alleviate the symptoms, but there is no pharmacological treatment. Microdosing lithium has been used to modify the pathological characteristics of the disease, with effects in both experimental and clinical conditions. The present work aimed to analyze the effects of this treatment on spatial memory, anxiety, and molecular mechanisms related to long-term memory formation during the aging process of a mouse model of accelerated aging (SAMP-8). Female SAMP-8 showed learning and memory impairments together with disruption of memory mechanisms, neuronal loss, and increased density of senile plaques compared to their natural control strain, the senescence-accelerated mouse resistant (SAMR-1). Chronic treatment with lithium promoted memory maintenance, reduction in anxiety, and maintenance of proteins related to memory formation and neuronal density. The density of senile plaques was also reduced. An increase in the density of gamma-aminobutyric acid A (GABAA) and α7 nicotinic cholinergic receptors was also observed and related to neuroprotection and anxiety reduction. In addition, this microdose of lithium inhibited the activation of glycogen synthase kinase-3beta (GSK-3β), the classical mechanism of lithium cell effects, which could contribute to the preservation of the memory mechanism and reduction in senile plaque formation. This work shows that lithium effects in neuroprotection along the aging process are not related to a unique cellular mechanism but produce multiple effects that slowly protect the brain along the aging process.

Osteocyte-derived sclerostin impairs cognitive function during ageing and Alzheimer's disease progression

Ageing increases susceptibility to neurodegenerative disorders, such as Alzheimer's disease (AD). Serum levels of sclerostin, an osteocyte-derived Wnt-β-catenin signalling antagonist, increase with age and inhibit osteoblastogenesis. As Wnt-β-catenin signalling acts as a protective mechanism for memory, we hypothesize that osteocyte-derived sclerostin can impact cognitive function under pathological conditions. Here we show that osteocyte-derived sclerostin can cross the blood-brain barrier of old mice, where it can dysregulate Wnt-β-catenin signalling. Gain-of-function and loss-of-function experiments show that abnormally elevated osteocyte-derived sclerostin impairs synaptic plasticity and memory in old mice of both sexes. Mechanistically, sclerostin increases amyloid β (Aβ) production through β-catenin-β-secretase 1 (BACE1) signalling, indicating a functional role for sclerostin in AD. Accordingly, high sclerostin levels in patients with AD of both sexes are associated with severe cognitive impairment, which is in line with the acceleration of Αβ production in an AD mouse model with bone-specific overexpression of sclerostin. Thus, we demonstrate osteocyte-derived sclerostin-mediated bone-brain crosstalk, which could serve as a target for developing therapeutic interventions against AD.

Low and very low lithium levels: Thyroid effects are small but still require monitoring

AIM

Low doses of lithium, as might be used for mood or dementia prevention, do not carry the same renal, toxicity, and tolerability problems of doses used for prophylaxis or treatment of mania. However, thyroid effects of low doses have not been investigated. Our goal in this study was to assess the changes in thyroid-stimulating hormone (TSH) associated with a broad range of lithium levels, including those well below the therapeutic range for bipolar disorders.

METHODS

This study was conducted in a small healthcare system with 19 associated primary care clinics served by a Collaborative Care program of psychiatric consultation. In this retrospective review of electronic records, we searched for patients who had received a lithium prescription and both pre- and post-lithium thyroid-stimulating hormone (TSH) levels.

RESULTS

Patients with low lithium levels (<0.5 mEq/L, N = 197) had a mean thyroid-stimulating hormone (TSH) increase of 0.52 mIU/L. Patients with maintenance lithium levels (0.5-0.8 mEq/L; N = 123) had a mean TSH increase of 1.01 mIU/L; and patients with antimanic lithium levels (>0.8 mEq/L; N = 79) had a mean TSH increase of 2.16 mIU/L. The probability of TSH exceeding the upper limit of normal in our laboratory (>4.2 mIU/L) was positively associated with pre-lithium TSH.

CONCLUSION

These results suggest that the risk of lithium-induced hypothyroidism is dose-related, and relatively small with very low doses, but thyroid monitoring, including a pre-lithium TSH, is still warranted.

Why is lithium [not] the drug of choice for bipolar disorder? a controversy between science and clinical practice

BACKGROUND

During over half a century, science has shown that lithium is the most efficacious treatment for bipolar disorder but despite this, its prescription has consistently declined internationally during recent decades to approximately 35% ever use or less of patients with bipolar disorder.

CONTENT

This narrative review provides an overview of the decreasing use of lithium in bipolar disorder internationally, shortly summarises the evidence for lithium's acute and prophylactic effects in bipolar disorder, discuss the challenges in relation to lithium including side effects, long-term risks and myths around lithium and provides two detailed examples on how specialised care models may result in successful increase of the use of lithium to 70% of patients with bipolar disorder largescale and improve care regionally and nationally.

CONCLUSIONS

Decades of scientific investigations and education and teaching of clinicians and the public has not increased the use of lithium on a population-based large scale. It is argued that lithium should be the drug of choice for maintenance therapy as the single first-line treatment and that organizational changes are needed with specialised care for bipolar disorder to systematically and long-term change the use of lithium on a large-scale population-level.

Mortality and Lithium-Protective Effects after First-Episode Mania Diagnosis in Bipolar Disorder: A Nationwide Retrospective Cohort Study in Taiwan

INTRODUCTION

This study aimed to estimate all-cause mortality in patients after a first-episode mania (FEM) and examine whether six guideline-recommended medications can reduce mortality.

METHODS

The cohort included population-based FEM samples and matched controls from Taiwan, spanning 2007 to 2018. The primary outcomes assessed were all-cause/suicide-related mortality, while the secondary outcome focused on mortality associated with pharmacological treatments. We compared mortality in post-FEM patients and age-/sex-matched controls without any diagnosed bipolar disorders and patients with and without psychopharmacological treatment using Cox regression analysis, respectively. Statistics were presented with time-to-event adjusted hazard ratios (AHRs) and 95% confidence intervals (CIs).

RESULTS

The study included 54,092 post-FEM patients and 270,460 controls, totaling 2,467,417 person-years of follow-up. Post-FEM patients had higher risks of all-cause mortality (AHR 2.38, 95% CI: 2.31-2.45) and suicide death (10.80, 5.88-19.84) than controls. Lithium (0.62, 0.55-0.70), divalproex (0.89, 0.83-0.95), and aripiprazole (0.81, 0.66-1.00) were associated with reduced all-cause mortality compared to non-users. There were no significant all-cause mortality differences for quetiapine (0.95, 0.89-1.01), risperidone (0.92, 0.82-1.02), and paliperidone (1.24, 0.88-1.76) users. When accounting for drug action onset times in sensitivity analyses, only lithium significantly reduced all-cause mortality (AHR range 0.65-0.72). There were 35 and 16 suicide deaths in post-FEM patients and controls, respectively. No drug had a significant effect on suicide deaths (lithium: 6; divalproex: 7; aripiprazole: 0; quetiapine: 10; risperidone: 4; paliperidone: 1).

CONCLUSION

Post-FEM patients had a higher risk of all-cause/suicide-related mortality, and lithium treatment might reduce all-cause mortality.

[Lithium treatment for affective disorders in old age]

BACKGROUND

Lithium is considered the gold standard for the treatment of bipolar affective disorder for the prevention of recurrence of manic and depressive episodes and for augmentation treatment in unipolar severe depressive episodes. The indications for treatment with lithium do not differ for older or younger patients. Nevertheless, there are a number of aspects to be considered with respect to drug safety in the group of old patients.

OBJECTIVE

The aim was to give an overview of the current literature on lithium treatment in old age and from this to derive recommendations for action.

MATERIAL AND METHODS

A selective literature review on lithium treatment in old age was conducted to answer questions on drug safety, monitoring (particularly with respect to comorbidities) and potential alternatives to lithium.

RESULTS AND DISCUSSION

Lithium is an effective and, if used correctly, safe drug also in old people; however, with respect to somatic comorbidities that increase with age, special caution is required when using lithium in order to prevent nephropathy and intoxication.

Low-dose lithium adjunct to quetiapine improves cognitive task performance in mice with MK801-induced long-term cognitive impairment: Evidence from a pilot study

BACKGROUND

Low-dose lithium (LD-Li) has been shown to rescue cognitive impairment in mouse models of short-term mild cognitive impairment, dementia, and schizophrenia. However, few studies have characterized the effects of LD-Li, alone or in conjunction with anti-psychotics, in the mouse model of MK801-induced long term cognitive impairment.

METHODS

The present study used in vivo Ca2+ imaging and a battery of cognitive function assessments to investigate the long-term effects of LD-Li on cognition in mice exposed to repeated injections of MK801. Prefrontal Ca2+ activity was visualized to estimate alterations in neural activity in the model mice. Pre-pulse inhibition (PPI), novel object recognition (NOR), Morris water maze (MWM), and fear conditioning (FC) tasks were used to characterize cognitive performance; open field activity (OFA) testing was used to observe psychotic symptoms. Two treatment strategies were tested: LD-Li [250 mg/d human equivalent dose (HED)] adjunct to quetiapine (QTP; 600 mg/d HED); and QTP-monotherapy (mt; 600 mg/d HED).

RESULTS

Compared to the QTP-mt group, the LD-Li + QTP group showed greatly improved cognitive performance on all measures between experimental days 29 and 85. QTP-mt improved behavioral measures compared to untreated controls, but the effects persisted only from day 29 to day 43. These data suggest that LD-Li + QTP is superior to QTP-mt for improving long-term cognitive impairments in the MK801 mouse model.

LIMITATIONS

There is no medical consensus regarding lithium use in patients with schizophrenia.

CONCLUSION

More pre-clinical and clinical studies are needed to further investigate effective treatment strategies for patients with long-term cognitive impairments, such as chronic schizophrenia.

Impact of psychotropic medications on cognition among older adults: a systematic review

OBJECTIVES

The aim of this systematic review is to examine the cognitive impact of psychotropic medications including benzodiazepines, antidepressants, mood stabilizers, antipsychotics, or a combination of these drugs on older adults.

DESIGN

Systematic review.

SETTING

We searched Medline, PsycINFO, and Embase through the Ovid platform, CINAHL through EBSCO, and Web of Science.

PARTICIPANTS AND INTERVENTIONS

Randomized control trials (RCTs) and cohort studies that used a validated scale to measure cognition with a follow-up period of at least six months were included.

MEASUREMENT

The primary outcome of interest was cognitive change associated with psychotropic medication use.

RESULTS

A total of 7551 articles were identified from the primary electronic literature search across the five databases after eliminating duplicates. Based on full-text analysis, 27 articles (two RCTs, 25 cohorts) met the inclusion criteria. Of these, nine each examined the impact of benzodiazepines and antidepressants, five examined psychotropic combinations, three on antipsychotic drugs, and one on the effects of mood stabilizers.

CONCLUSIONS

This is the first systematic review to examine the cognitive impact of multiple psychotropic drug classes in older adults over an extended follow-up period (six months or more) using robust sample sizes, drug-free control groups, and validated cognitive instruments. We found evidence to indicate cognitive decline with the cumulative use of benzodiazepines and the use of antidepressants, especially those with anticholinergic properties among older adults without cognitive impairment at baseline. Further, the use of antipsychotics and psychotropic combinations is also associated with cognitive decline in older adults.

Lithium and risk of cardiovascular disease, dementia and venous thromboembolism

OBJECTIVE

To determine if long-term lithium treatment is associated with protective effects or increased risk of vascular, neurological, and renal disorders.

METHODS

Using nationwide registers, we included all citizens of Finland with dispensations of lithium for three or more consecutive years between 1995 and 2016. We identified 9698 cases and matched 96,507 controls without lithium treatment. Studied outcomes were vascular, neurological, renal disorders, and suicide. Analyses were performed applying Cox proportional hazards modeling in full cohort and in further subcohort analysis of individuals with a comparable diagnosis of mood or psychotic disorder.

RESULTS

Lithium users had a significantly higher overall disease burden compared to matched population controls, including a higher risk of cardiovascular and cerebrovascular disorders and dementia. However, compared to individuals with a diagnosis of mood or psychotic disorders without lithium treatment, we observed a lower risk of cardiovascular and cerebrovascular disorders (HR = 0.80, 99% CI = 0.73-0.89), and no significant difference for dementia (HR = 1.15, 99% CI = 0.99-1.33), in lithium users. Pulmonary embolism was more common in the lithium-treated cases both in comparison to the general population (HR = 2.86, 99% CI = 2.42-3.37) and in comparison to the psychiatric subcohort (HR = 1.68, 99% CI = 1.31-2.17). Similarly, the risks of Parkinson's disease and kidney disease were higher in both comparisons.

CONCLUSIONS

We conclude that individuals prescribed lithium have a lower risk of cardiovascular and cerebrovascular disease, but no marked effect on dementia, compared to individuals with a mood or psychotic disorder not prescribed lithium. Venous thromboembolism, Parkinson's disease, and kidney disease were significantly more prevalent in individuals prescribed lithium.

The Synergistic Potential of Combining PD-1/PD-L1 Immune Checkpoint Inhibitors with NOD2 Agonists in Alzheimer's Disease Treatment

Our research over the past decade has compellingly demonstrated the potential of Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) receptor agonists in Alzheimer's disease (AD) treatment. These agonists facilitate the conversation of pro-inflammatory monocytes into patrolling monocytes, leading to the efficient clearance of amyloid-β (Aβ) in the AD-affected cerebrovascular system. This approach surpasses the efficacy of targeting Aβ formation, marking a significant shift in therapeutic strategies. Simultaneously, inhibitors of PD-1/PD-L1 immune check point or glycogen synthase kinase 3 beta (GSK3β), which modulates PD-1, have emerged as potent AD treatment modalities. PD-1 inhibitor exhibits a profound potential in monocytes' recruitment to the AD-afflicted brain. Recent evidence suggests that an integrated approach, combining the modulation of NOD2 and PD-1, could yield superior outcomes. This innovative combinatorial therapeutic approach leverages the potential of MDP to act as a catalyst for the conversion of inflammatory monocytes into patrolling monocytes, with the subsequent recruitment of these patrolling monocytes into the brain being stimulated by the PD-1 inhibitor. These therapeutic interventions are currently under preclinical investigation by pharmaceutical entities, underscoring the promise they hold. This research advocates for the modulation, rather than suppression, of the innate immune system as a promising pharmacological strategy in AD.

Determination by ICP-MS of Essential and Toxic Trace Elements in Gums and Carrageenans Used as Food Additives Commercially Available in the Portuguese Market

Gums and carrageenans are food additives widely used in food preparations to improve texture and as viscosifiers. Although they are typically added in small amounts, nowadays people tend to use more and more pre-prepared food. In this work, the content of a wide panel of trace elements in commercial products were analyzed. Carrageenans and gums (n = 13) were purchased in the Portuguese market and were from European suppliers. Samples were solubilized by closed-vessel microwave-assisted acid digestion and analyzed by ICP-MS. Globally, the content of essential trace elements decreased in the following order: Fe (on average, on the order of several tens of µg/g) > Mn > Zn > Cr > Cu > Co > Se > Mo (typically < 0.1 µg/g), while the content of non-essential/toxic trace elements decreased in the following order: Al > Sr > Rb > As > Li > Cd > Pb > Hg. The consumption of these food additives can significantly contribute to the daily requirements of some essential trace elements, namely Cr and Mo. The toxic trace elements Cd, As, Pb, and Hg were below the EU regulatory limits in all analyzed samples. Additional research is needed to define the potential risk of introducing toxic trace elements into food products through the use of these additives.

Neurostructural and neurocognitive correlates of APOE ε4 in youth bipolar disorder

BACKGROUND

Bipolar disorder (BD) is a clinical risk factor for Alzheimer's disease (AD). Apolipoprotein E ε4 (APOE ε4), a genetic risk factor for AD, has been associated with brain structure and neurocognition in healthy youth.

AIMS

We evaluated whether there was an association between APOE ε4 with neurostructure and neurocognition in youth with BD.

METHODS

Participants included 150 youth (78 BD:19 ε4-carriers, 72 controls:17 ε4-carriers). 3T-magnetic resonance imaging yielded measures of cortical thickness, surface area, and volume. Regions-of-interest (ROI) and vertex-wise analyses of the cortex were conducted. Neurocognitive tests of attention and working memory were examined.

RESULTS

Vertex-wise analyses revealed clusters with a diagnosis-by-APOE ε4 interaction effect for surface area (p = 0.002) and volume (p = 0.046) in pars triangularis (BD ε4-carriers > BD noncarriers), and surface area (p = 0.03) in superior frontal gyrus (controls ε4-carriers > other groups). ROI analyses were not significant. A significant interaction effect for working memory (p = 0.001) appeared to be driven by nominally poorer performance in BD ε4-carriers but not control ε4-carriers; however, post hoc contrasts were not significant.

CONCLUSIONS

APOE ε4 was associated with larger neurostructural metrics in BD and controls, however, the regional association of APOE ε4 with neurostructure differed between groups. The role of APOE ε4 on neurodevelopmental processes is a plausible explanation for the observed differences. Future studies should evaluate the association of APOE ε4 with pars triangularis and its neurofunctional implications among youth with BD.

[Effects of lithium, valproic acid, carbamazepine and antipsychotic agents on cognition in bipolar disorders-A systematic review]

BACKGROUND

Until now the long-term consequences of the medical treatment for bipolar disorder have barely been examined, especially the consequences with respect to cognitive impairment and dementia. Some studies show signs that some treatment options have a better effect on the brain than others. This review summarizes the current state of research.

OBJECTIVE

The effects of long-term consequences of lithium, valproic acid, carbamazepine and antipsychotic agents on the development of dementia or cognitive impairments in patients with bipolar disorder were investigated.

METHODS

A systematic literature search was carried out in the PubMed data base from May to July 2022.

RESULTS

The majority of studies showed that lithium has a neuroprotective effect and can lower the risk of developing dementia, whereas an increased risk was found in patients taking valproic acid. There are only very few studies that deal with antipsychotic medication and the long-term consequences concerning dementia.

CONCLUSION

Lithium should be recommended for the long-term treatment of bipolar disorder. Valproic acid should not or carefully be used as it can affect the risk of developing dementia. With respect to antipsychotics there is no recommendation as more studies are needed to evaluate the long-term consequences.

[Lithium treatment for affective disorders in old age]

BACKGROUND

Lithium is considered the gold standard for the treatment of bipolar affective disorder for the prevention of recurrence of manic and depressive episodes and for augmentation treatment in unipolar severe depressive episodes. The indications for treatment with lithium do not differ for older or younger patients. Nevertheless, there are a number of aspects to be considered with respect to drug safety in the group of old patients.

OBJECTIVE

The aim was to give an overview of the current literature on lithium treatment in old age and from this to derive recommendations for action.

MATERIAL AND METHODS

A selective literature review on lithium treatment in old age was conducted to answer questions on drug safety, monitoring (particularly with respect to comorbidities) and potential alternatives to lithium.

RESULTS AND DISCUSSION

Lithium is an effective and, if used correctly, safe drug also in old people; however, with respect to somatic comorbidities that increase with age, special caution is required when using lithium in order to prevent nephropathy and intoxication.

Effect of dietary patterns on cognitive functions of older adults: A systematic review and meta-analysis of randomized controlled trials: Dietary Patterns on Cognition of Older Adults

BACKGROUND

Dietary patterns are associated with cognitive benefits, but inconsistent findings have been reported concerning this association. This study aims to provide a more comprehensive review and higher evidence level by evaluating evidence from randomized controlled trials (RCTs) exploring effects of various dietary patterns on cognitive function outcomes in older adults.

METHODS

This systematic review and meta-analysis study followed the PRISMA guidelines. Twelves search engines and databases were searched for papers published up until March 2022. Random-effects models were used to calculate effect size (ES).

RESULTS

Twenty-two RCTs met our inclusion criteria. A wide range of cognitive measures were used across the included studies. To reduce heterogeneity and to ensure a sufficient number of studies for meaningful interpretation, we utilized global cognition as the outcome measure. Only nine studies used global cognition measures, including the Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), Cognitive Abilities Screening Instrument (CASI), or neuropsychological test battery. Additionally, seven dietary patterns were identified in these studies. The results demonstrated that dietary patterns achieved a significant improvement on cognitive function outcomes including the MMSE/CASI (ES = 0.303; 95% CI [0.045, 0.560]), the ADAS-Cog (ES = -0.277; 95% CI [-0.515, -0.039]), and the cognitive battery (ES = 0.132; 95% CI [0.010, 0.255]).

CONCLUSIONS

Multidisciplinary health-care professionals may use this information as a reference when planning elder care. More large-scale, high-quality studies are required to explore the long-term effects of healthy dietary patterns on global cognition, other cognitive domains, and life quality among older adults.

Low-Dose Lithium Supplementation Influences GSK3β Activity in a Brain Region Specific Manner in C57BL6 Male Mice

BACKGROUND

Lithium, a commonly used treatment for bipolar disorder, has been shown to have neuroprotective effects for other conditions including Alzheimer's disease via the inhibition of the enzyme glycogen synthase kinase-3 (GSK3). However, dose-dependent adverse effects of lithium are well-documented, highlighting the need to determine if low doses of lithium can reliably reduce GSK3 activity.

OBJECTIVE

The purpose of this study was to evaluate the effects of a low-dose lithium supplementation on GSK3 activity in the brain of an early, diet-induced Alzheimer's disease model.

METHODS

Male C57BL/6J mice were divided into either a 6-week or 12-week study. In the 6-week study, mice were fed a chow diet or a chow diet with lithium-supplemented drinking water (10 mg/kg/day) for 6 weeks. Alternatively, in the 12-week study, mice were fed a chow diet, a high-fat diet (HFD), or a HFD with lithium-supplemented drinking water for 12 weeks. Prefrontal cortex and hippocampal tissues were collected for analysis.

RESULTS

Results demonstrated reduced GSK3 activity in the prefrontal cortex as early as 6 weeks of lithium supplementation, in the absence of inhibitory phosphorylation changes. Further, lithium supplementation in an obese model reduced prefrontal cortex GSK3 activity as well as improved insulin sensitivity.

CONCLUSION

Collectively, these data provide evidence for low-dose lithium supplementation to inhibit GSK3 activity in the brain. Moreover, these results indicate that GSK3 activity can be inhibited despite any changes in phosphorylation. These findings contribute to an overall greater understanding of low-dose lithium's ability to influence GSK3 activity in the brain and its potential as an Alzheimer's disease prophylactic.

Long-Term Lithium Therapy: Side Effects and Interactions

Lithium remains the drug of first choice for prophylactic treatment of bipolar disorder, preventing the recurrences of manic and depressive episodes. The longitudinal experiences with lithium administration greatly exceed those with other mood stabilizers. Among the adverse side effects of lithium, renal, gastrointestinal, neurological, thyroid, metabolic, cognitive, dermatological, cardiologic, and sexual are listed. Probably, the most important negative effect of lithium, occurring mostly after 10-20 years of its administration, is interstitial nephropathy. Beneficial side-effects of long-term lithium therapy also occur such as anti-suicidal, antiviral, and anti-dementia ones. Pharmacokinetic and pharmacodynamic interactions of lithium, mostly those with other drugs, may have an impact on the success of long-term lithium treatment. This paper makes the narrative updated review of lithium-induced side-effects and interactions that may influence its prophylactic effect in bipolar disorder. Their description, mechanisms, and management strategies are provided. The papers appearing in recent years focused mainly on the long-term lithium treatment are reviewed in detail, including recent research performed at Department of Psychiatry, Poznan University of Medical Sciences, Poland. Their own observations on ultra-long lithium treatment of patients with bipolar disorder are also presented. The review can help psychiatrists to perform a successful lithium prophylaxis in bipolar patients.

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

OBJECTIVES

There is limited information on the characteristics of older adults with bipolar disorder (OABD) treated with lithium, along with safety concerns about its use by older adults. The aim of the present study is to describe the demographic and clinical characteristics of OABD receiving lithium therapy, using data from the Global Ageing & Geriatric Experiments in Bipolar Disorder (GAGE-BD).

EXPERIMENTAL PROCEDURES

Cross-sectional analysis of the GAGE-BD dataset to determine differences and similarities between lithium users and non-users. We analysed data from 986 participants aged 50 years or older (mean age 63.5 years; 57.5% females) from 12 study sites. Two subgroups ('Lithium'; 'Non-lithium') were defined according to the current prescription of lithium. We compared several outcomes between these groups, controlling for age, gender, and study site.

RESULTS

OABD treated with lithium had lower scores on depression rating scales and were less likely to be categorised as with moderate or severe depression. There was a lower proportion of lithium users than non-users among those with evidence of rapid cycling and non-bipolar psychiatric diagnoses. Assessment of global cognitive state and functionality indicated better performance among lithium users. The current use of antipsychotics was less frequent among lithium users, who also reported fewer cardiovascular comorbidities than non-users.

CONCLUSION

We found several potentially relevant differences in the clinical profile of OABD treated with lithium compared with those treated with other mood stabilisers. However, the interpretation of the present results must take into account the methodological limitations inherent to the cross-sectional approach and data harmonisation.

Lithium Biological Action Mechanisms after Ischemic Stroke

Lithium is a source of great scientific interest because although it has such a simple structure, relatively easy-to-analyze chemistry, and well-established physical properties, the plethora of effects on biological systems—which influence numerous cellular and molecular processes through not entirely explained mechanisms of action—generate a mystery that modern science is still trying to decipher. Lithium has multiple effects on neurotransmitter-mediated receptor signaling, ion transport, signaling cascades, hormonal regulation, circadian rhythm, and gene expression. The biochemical mechanisms of lithium action appear to be multifactorial and interrelated with the functioning of several enzymes, hormones, vitamins, and growth and transformation factors. The widespread and chaotic marketing of lithium salts in potions and mineral waters, always at inadequate concentrations for various diseases, has contributed to the general disillusionment with empirical medical hypotheses about the therapeutic role of lithium. Lithium salts were first used therapeutically in 1850 to relieve the symptoms of gout, rheumatism, and kidney stones. In 1949, Cade was credited with discovering the sedative effect of lithium salts in the state of manic agitation, but frequent cases of intoxication accompanied the therapy. In the 1960s, lithium was shown to prevent manic and also depressive recurrences. This prophylactic effect was first demonstrated in an open-label study using the “mirror” method and was later (after 1970) confirmed by several placebo-controlled double-blind studies. Lithium prophylaxis was similarly effective in bipolar and also unipolar patients. In 1967, the therapeutic value of lithemia was determined, included in the range of 0.5–1.5 mEq/L. Recently, new therapeutic perspectives on lithium are connected with improved neurological outcomes after ischemic stroke. The effects of lithium on the development and maintenance of neuroprotection can be divided into two categories: short-term effects and long-term effects. Unfortunately, the existing studies do not fully explain the lithium biological action mechanisms after ischemic stroke.

A Metallomic Approach to Assess Associations of Plasma Metal Levels with Amnestic Mild Cognitive Impairment and Alzheimer's Disease: An Exploratory Study

Alzheimer’s disease (AD) involves the abnormal activity of transition metals and metal ion dyshomeostasis; however, the potential of trace metal biomarkers in predicting cognitive decline has not been evaluated. This study aimed to assess the potential of 36 trace elements in predicting cognitive decline in patients with amnestic mild cognitive impairment (aMCI) or AD. Participants (9 controls, 23 aMCI due to AD, and 8 AD dementia) underwent comprehensive cognitive tests, including the Mini-Mental State Examination (MMSE) and trace metal analysis. The correlations between the plasma trace element levels and annual MMSE changes during follow-up were analyzed. We found that an increase in disease severity was linked to lower plasma levels of boron (B), bismuth (Bi), thorium (Th), and uranium (U) (adjusted p < 0.05). Higher baseline calcium levels (r = 0.50, p = 0.026) were associated with less annual cognitive decline; those of B (r = −0.70, p = 0.001), zirconium (r = −0.58, p = 0.007), and Th (r = −0.52, p = 0.020) with rapid annual cognitive decline in the aMCI group; and those of manganese (r = −0.91, p = 0.035) with rapid annual cognitive decline in the AD group. Overall, our exploratory study suggests that plasma metal levels have great potential as in vivo biomarkers for aMCI and AD. Larger sample studies are necessary to confirm these results.

Lithium bidirectionally regulates depression- and mania-related brain functional alterations without worsening cognitive function in patients with bipolar disorder

Lithium monotherapy has been proposed to have antidepressant and antimanic effects in patients with bipolar disorder (BP). However, so far, it is lack of evidence to support this proposition. The main aim of this study was to test the hypothesis that lithium bidirectionally regulates depression- and mania-related brain functional abnormalities in patients with BP. We also assessed the effects of lithium, alone and in combination with other pharmacological treatments, on patients' cognitive performance. We enrolled 149 drug-naïve patients with BP; 99 patients experiencing first depressive episodes were allocated randomly to four treatment groups [lithium (DP/Li), lithium with lamotrigine (LTG; DP/Li+LTG), LTG (DP/LTG), and valproate (VPA) with LTG (DP/VPA+LTG)], and 50 experiencing first hypo-manic episodes were allocated to two treatment groups (MA/Li and MA/VPA). For comparative analysis, 60 age-matched healthy individuals were also recruited. Whole-brain global and regional resting-state cerebral blood flow (rs-CBF) and cognitive alterations were examined before and after 12-week treatment. We have the following findings: DP/Li+LTG, and to a lesser extent DP/Li, alleviated the depression-related reduction in rs-CBF. MA/VPA and MA/Li reversed the mania-related elevation of rs-CBF completely and partially, respectively. Lithium alone improved cognitive performance during depressive and manic episodes; other tested treatments have no such effect or worsened cognitive ability. Our results showed that lithium bidirectionally regulates depression- and mania-associated brain functional abnormalities in patients with BP. Lithium monotherapy has a better antimanic effect than VPA, is superior to other tested treatments in improving cognition during the course of BP, and has satisfactory antidepressant effects in patients with BP.