Exploring the genetics of lithium response in bipolar disorders.

BACKGROUND: Lithium (Li) remains the treatment of choice for bipolar disorders (BP). Its mood-stabilizing effects help reduce the long-term burden of mania, depression and suicide risk in patients with BP. It also has been shown to have beneficial effects on disease-associated conditions, including sleep and cardiovascular disorders. However, the individual responses to Li treatment vary within and between diagnostic subtypes of BP (e.g. BP-I and BP-II) according to the clinical presentation. Moreover, long-term Li treatment has been linked to adverse side-effects that are a cause of concern and non-adherence, including the risk of developing chronic medical conditions such as thyroid and renal disease. In recent years, studies by the Consortium on Lithium Genetics (ConLiGen) have uncovered a number of genetic factors that contribute to the variability in Li treatment response in patients with BP. Here, we leveraged the ConLiGen cohort (N = 2064) to investigate the genetic basis of Li effects in BP. For this, we studied how Li response and linked genes associate with the psychiatric symptoms and polygenic load for medical comorbidities, placing particular emphasis on identifying differences between BP-I and BP-II. RESULTS: We found that clinical response to Li treatment, measured with the Alda scale, was associated with a diminished burden of mania, depression, substance and alcohol abuse, psychosis and suicidal ideation in patients with BP-I and, in patients with BP-II, of depression only. Our genetic analyses showed that a stronger clinical response to Li was modestly related to lower polygenic load for diabetes and hypertension in BP-I but not BP-II. Moreover, our results suggested that a number of genes that have been previously linked to Li response variability in BP differentially relate to the psychiatric symptomatology, particularly to the numbers of manic and depressive episodes, and to the polygenic load for comorbid conditions, including diabetes, hypertension and hypothyroidism. CONCLUSIONS: Taken together, our findings suggest that the effects of Li on symptomatology and comorbidity in BP are partially modulated by common genetic factors, with differential effects between BP-I and BP-II.

Exploring the genetics of lithium response in bipolar disorders.

Background: Lithium (Li) remains the treatment of choice for bipolar disorders (BP). Its mood-stabilizing effects help reduce the long-term burden of mania, depression and suicide risk in patients with BP. It also has been shown to have beneficial effects on disease-associated conditions, including sleep and cardiovascular disorders. However, the individual responses to Li treatment vary within and between diagnostic subtypes of BP (e.g. BP-I and BP-II) according to the clinical presentation. Moreover, long-term Li treatment has been linked to adverse side-effects that are a cause of concern and non-adherence, including the risk of developing chronic medical conditions such as thyroid and renal disease. In recent years, studies by the Consortium on Lithium Genetics (ConLiGen) have uncovered a number of genetic factors that contribute to the variability in Li treatment response in patients with BP. Here, we leveraged the ConLiGen cohort (N=2,064) to investigate the genetic basis of Li effects in BP. For this, we studied how Li response and linked genes associate with the psychiatric symptoms and polygenic load for medical comorbidities, placing particular emphasis on identifying differences between BP-I and BP-II. Results: We found that clinical response to Li treatment, measured with the Alda scale, was associated with a diminished burden of mania, depression, substance and alcohol abuse, psychosis and suicidal ideation in patients with BP-I and, in patients with BP-II, of depression only. Our genetic analyses showed that a stronger clinical response to Li was modestly related to lower polygenic load for diabetes and hypertension in BP-I but not BP-II. Moreover, our results suggested that a number of genes that have been previously linked to Li response variability in BP differentially relate to the psychiatric symptomatology, particularly to the numbers of manic and depressive episodes, and to the polygenic load for comorbid conditions, including diabetes, hypertension and hypothyroidism. Conclusions: Taken together, our findings suggest that the effects of Li on symptomatology and comorbidity in BP are partially modulated by common genetic factors, with differential effects between BP-I and BP-II.

The effects of lithium on human red blood cells studied using optical spectroscopy and laser trap.

Lithium has been the treatment of choice for patients with bipolar disorder. However, lithium overdose happens more frequently since it has a very narrow therapeutic range in blood, necessitating investigation of its adverse effects on blood cells. The possible changes that lithium exposure may have on functional and morphological characteristics of human red blood cells (RBCs) have been studied ex vivo using single-cell Raman spectroscopy, optical trapping, and membrane fluorescent probe. The Raman spectroscopy was performed with excitation at 532 nm light, which also results in simultaneous photoreduction of intracellular hemoglobin (Hb). The level of photoreduction of lithium-exposed RBCs was observed to decline with lithium concentration, indicating irreversible oxygenation of intracellular Hb from lithium exposure. The lithium exposure may also have an effect on RBC membrane, which was investigated via optical stretching in a laser trap and the results suggest lower membrane fluidity for the lithium-exposed RBCs. The membrane fluidity of RBCs was further studied using the Prodan generalized polarization method and the results verify the reduction of membrane fluidity upon lithium exposure.

In vitro gastrointestinal digestion and bioavailability of lithium from processed lithiated and nonlithiated white Agaricus bisporus mushrooms.

AIM: In order to avoid side effects of lithium doses in some patients, some commonly cultivated mushroom species including A. bisporus have been successfully lithiated, with the potential to provide more acceptable sources of Li. This study assessed the in vitro release (potential bioaccessibility) and possible intake of Li using the action of artificial gastrointestinal juices on lithiated and nonlithiated (control) button mushrooms (Agaricus bisporus) that were subjected to certain modes of culinary processing. METHODS: In the in vitro release study, mushrooms were processed using a number of routinely used domestic treatments including rehydrating dried mushrooms, blanching and blanching followed by pickling of fresh or frozen mushrooms. The in vitro digestion procedure used artificial gastrointestinal juices in a two-stage methodology that was adapted from 'The Bioaccessibility Research Group of Europe' method. The Li concentrations were determined using an inductively coupled argon plasma-dynamic reactive cell-mass spectrometer. RESULTS: Lithium was found to be more bioaccessible from caps of lithiated mushrooms compared with nonlithiated. Releases from the caps and stipes of blanched or blanched and then pickled mushrooms through gastric digestion ranged from 32 ± 2 to 50 ± 1% relative to the dried product and was lower for gastrointestinal digestion, which ranged from 16 ± 1 to 20 ± 1%. CONCLUSION: Losses of Li sustained through blanching or blanching followed by pickling of fresh mushrooms (41-87% wet weight) combined with limited accessibility during gastrointestinal release (16-55%) result in much lower bioavailability of the dose from lithiated products. A 300-g meal would provide <5% of the Li (6 mg) required for potential preventative treatments, such as reducing suicide rates and lowering dementia risk.

Divergent Directionality of Immune Cell-Specific Protein Expression between Bipolar Lithium Responders and Non-Responders Revealed by Enhanced Flow Cytometry.

Background and Objectives: There is no biomarker to predict lithium response. This study used CellPrint™ enhanced flow cytometry to study 28 proteins representing a spectrum of cellular pathways in monocytes and CD4+ lymphocytes before and after lithium treatment in patients with bipolar disorder (BD). Materials and Methods: Symptomatic patients with BD type I or II received lithium (serum level ≥ 0.6 mEq/L) for 16 weeks. Patients were assessed with standard rating scales and divided into two groups, responders (≥50% improvement from baseline) and non-responders. Twenty-eight intracellular proteins in CD4+ lymphocytes and monocytes were analyzed with CellPrint™, an enhanced flow cytometry procedure. Data were analyzed for differences in protein expression levels. Results: The intent-to-treat sample included 13 lithium-responders (12 blood samples before treatment and 9 after treatment) and 11 lithium-non-responders (11 blood samples before treatment and 4 after treatment). No significant differences in expression between the groups was observed prior to lithium treatment. After treatment, the majority of analytes increased expression in responders and decreased expression in non-responders. Significant increases were seen for PDEB4 and NR3C1 in responders. A significant decrease was seen for NR3C1 in non-responders. Conclusions: Lithium induced divergent directionality of protein expression depending on the whether the patient was a responder or non-responder, elucidating molecular characteristics of lithium responsiveness. A subsequent study with a larger sample size is warranted.

Risk factors for early recurrence after discontinuing lithium in bipolar disorder.

BACKGROUND: Time to a new episode of bipolar disorder (BD) is shorter after discontinuing lithium rapidly. We now address this and other factors associated with the risk of early illness after discontinuing lithium. METHODS: We compared factors for association with recurrences of BD within 12 months of discontinuing long-term lithium treatment, using bivariate and multivariable analyses, as well as survival analysis to evaluate latency to new episodes versus rate of lithium-discontinuation and prior treatment duration. RESULTS: Among 227 BD subjects who received lithium for 4.47 [CI: 3.89-5.04] years and then discontinued, rapid treatment-discontinuation, and stopping for medical reasons were strongly associated with new illness-episodes within 12 months, as were diagnosis (BD-I > BD-II), greater morbidity during lithium-treatment, and less education, but neither longer treatment nor serum lithium concentrations. Discontinuation rate was strongly associated with shorter median latency to a new episode (rapid: 3.50; gradual [≥2 weeks]: 10.6 months), even with very early recurrences excluded to avoid potential contributions of emerging illness to treatment-discontinuation. Early recurrence was not associated with treatment-duration of ≥2 or ≥5 years or less. In multivariable logistic regression, rapid discontinuation, stopping for medical reasons, and BD-I diagnosis remained significantly, independently associated with early illness after lithium-discontinuation, with no effect of treatment duration. CONCLUSIONS: Early recurrence risk was again much greater after rapid discontinuation of lithium and discontinuing for medical reasons, somewhat greater with BD-I than BD-II, and following greater morbidity during lithium-treatment, but not related to dose or duration of preceding treatment exposure.

Lithium: A therapeutic option in Alzheimer's disease and its prodromal stages?

Experimental data reveal that lithium is capable of attenuating Alzheimer's disease pathology and stimulating adult hippocampal neurogenesis. Clinical studies show procognitive effects in lithium-treated patients with amnestic MCI and Alzheimer's disease. These procognitive effects are associated with changes of CSF biomarkers of Alzheimer's disease. After 3 months of lithium treatment with low lithium levels, a slowing of cognitive decline is observed in patients with Alzheimer's disease. In patients with amnestic MCI with low-dose lithium treatment a trend of a reduced Alzheimer's disease conversion rate and longer cognitive stability was reported. Thus, lithium might be a therapeutic option in the treatment of Alzheimer's disease and its prodromal stages. But its therapeutic efficacy needs further evaluation. Further studies should include head-to-head comparisons with approved dementia treatment options. Due to lithium's therapeutic toxicity a thorough preselection of patients and a closely therapeutic monitoring is necessary. This manuscript is based on a literature review.

Inflammation-Related Changes in Mood Disorders and the Immunomodulatory Role of Lithium.

Mood disorders are chronic, recurrent diseases characterized by changes in mood and emotions. The most common are major depressive disorder (MDD) and bipolar disorder (BD). Molecular biology studies have indicated an involvement of the immune system in the pathogenesis of mood disorders, and showed their correlation with altered levels of inflammatory markers and energy metabolism. Previous reports, including meta-analyses, also suggested the role of microglia activation in the M1 polarized macrophages, reflecting the pro-inflammatory phenotype. Lithium is an effective mood stabilizer used to treat both manic and depressive episodes in bipolar disorder, and as an augmentation of the antidepressant treatment of depression with a multidimensional mode of action. This review aims to summarize the molecular studies regarding inflammation, microglia activation and energy metabolism changes in mood disorders. We also aimed to outline the impact of lithium on these changes and discuss its immunomodulatory effect in mood disorders.

[Analysis of risk factors, etiology and treatment standard of lithium poisoning]. / Analyse zu Risikofaktoren, Ätiologie und Behandlungsstandard der Lithiumintoxikation.

Despite unlimited access to therapeutic drug monitoring lithium poisoning is still a common and potentially life-threatening but in most cases preventable complication of lithium treatment; however, it is still considered to be the gold standard in the treatment of affective disorders. The necessity of drug monitoring and potential lithium toxicity substantiate the skepticism of many therapists with respect to this often very effective treatment. This therefore limits the use of lithium although the unique therapeutic effects and high efficiency are well known. This retrospective data analysis of risk factors and etiology of lithium poisoning cases identified 58 cases of lithium poisoning, which were treated internally in this hospital between 2010 and 2014. Of the patients 67.2% were female and the majority were classified as chronic poisoning (66.1%). The most relevant patient-related risk factor seemed to be insufficient self-management as 26% of cases of lithium poisoning occurred during febrile infections or exsiccosis. Regarding practitioner-related risk factors, an insufficient consideration of drug interactions, insufficient therapeutic drug monitoring after dose increase and a paucity of experience and knowledge concerning lithium treatment were most relevant. This study illustrates the most important risk factors for lithium poisoning and their frequencies and contributes to raise awareness for this highly relevant topic. These data can help to prevent further cases of lithium poisoning. Furthermore, the results enable a comparison between the actual treatment reality and currently available evidence for the treatment of lithium poisoning.

Co-crystallization of human inositol monophosphatase with the lithium mimetic L-690,330.

Lithium, which is still the gold standard in the treatment of bipolar disorder, has been proposed to inhibit inositol monophosphatase (IMPase) and is hypothesized to exert its therapeutic effects by attenuating phosphatidylinositol (PI) cell signalling. Drug-discovery efforts have focused on small-molecule lithium mimetics that would specifically inhibit IMPase without exhibiting the undesired side effects of lithium. L-690,330 is a potent bisphosphonate substrate-based inhibitor developed by Merck Sharp & Dohme. To aid future structure-based inhibitor design, determination of the exact binding mechanism of L-690,330 to IMPase was of interest. Here, the high-resolution X-ray structure of human IMPase in complex with L690,330 and manganese ions determined at 1.39 Šresolution is reported.

Changes in white matter microstructure predict lithium response in adolescents with bipolar disorder.

OBJECTIVES: To investigate whether response to lithium treatment in pediatric bipolar disorder can be predicted by changes in white matter microstructure in key cortico-limbic tracts involved in emotion regulation. METHODS: Eighteen clinically referred lithium-naive patients (mean age 15.5 years) were administered clinical rating scales and diffusion tensor imaging (DTI) examinations at baseline and following 4 weeks of lithium treatment. Clinical ratings were repeated following 8 weeks of treatment. Patients with Clinical Global Impressions (CGI) ratings of 1 ("very much improved") or 2 ("much improved") were classified as responders. Ten healthy volunteers received baseline and follow-up DTI examinations. Using the ENIGMA pipeline, we investigated the relationship between changes in fractional anisotropy (FA) in the cingulum hippocampus (CGH) and clinical response to lithium. RESULTS: Patients demonstrated significantly lower FA compared to healthy volunteers in the left and right CGH white matter at baseline. Following 4 weeks of lithium treatment, FA in the left CGH increased in patients, but no significant changes in FA were observed among the untreated healthy volunteers. Lithium responders had a significantly greater increase in FA compared to non-responders. Moreover, baseline (pre-treatment) FA in the left CGH white matter significantly predicted week 8 overall CGI severity score, with post hoc analyses indicating that these effects were evident for both severity of depression and mania. CONCLUSIONS: Our findings suggest that response to lithium treatment in pediatric bipolar disorder is associated with normalization of white matter microstructure in regions associated with emotion processing.

Thyroid autoimmunity in bipolar disorder: A systematic review.

BACKGROUND: Accumulating evidence points to the pathophysiological relevance between immune dysfunction and mood disorders. High rates of thyroid dysfunction have been found in patients with bipolar disorder (BD), compared to the general population. A systematic review of the relationship between BD and thyroid autoimmunity was performed. METHODS: Pubmed, EMBASE and PsycINFO databases were searched up till January 28th, 2017. This review has been conducted according to the PRISMA statements. Observational studies clearly reporting data among BD patients and the frequency of autoimmune thyroid pathologies were included. RESULTS: 11 original studies met inclusion criteria out of 340 titles first returned from the global search. There is evidence of increased prevalence of circulating thyroid autoantibodies in depressed and mixed BD patients, while there is no evidence showing a positive relationship between BD and specific autoimmune thyroid diseases. There is a controversy about the influence of lithium exposure on circulating thyroid autoantibodies, even if most of studies seem not to support this association. A study conducted on bipolar twins suggests that autoimmune thyroiditis is related to the genetic vulnerability to develop BD rather than to the disease process itself. Females are more likely to develop thyroid autoimmunity. LIMITATIONS: The samples, study design and outcomes were heterogeneous. CONCLUSION: Thyroid autoimmunity has been suggested to be an independent risk factor for bipolar disorder with no clear association with lithium exposure and it might serve as an endophenotype for BD.

Lithium alleviates neurotoxic prion peptide-induced synaptic damage and neuronal death partially by the upregulation of nuclear target REST and the restoration of Wnt signaling.

Prion diseases are a group of infectious neurodegenerative diseases characterized by multiple neuropathological hallmarks, including accumulation of PrPSc, synaptic damage, and neuronal death. We previously reported that the repressor element 1-silencing transcription factor (REST), a novel neuroprotective marker in neurodegeneration, protects neurons against neurotoxic peptide (PrP106-126)-induced neurotoxicity, but fails to maintain survival following prolonged exposure to PrP106-126. Because Wnt signaling partially induces REST and is activated by lithium, we investigated the effects of lithium on REST in prion diseases. Lithium restores nuclear expression of REST, which is essential for regulating survival proteins. Lithium also mimics neuroprotective functions when REST is blocked, and these beneficial effects are additive with REST overexpression under physiological conditions. Reciprocally, under PrP106-126-stimulated pathological conditions, REST plays a critical role in the neuroprotective mechanisms of lithium treatment. Although lithium recovers Wnt signaling by inhibiting glycogen synthase kinase-3ß and stabilizing ß-catenin, restores survival associated proteins after exposure to PrP106-126 in primary cortical neurons. Knockdown of REST significantly suppresses the neuroprotective function of lithium. Conversely, overexpression of REST partially recovers its actions. Notably, lithium directly alleviates PrP106-126-induced synaptic damage and neuronal cell death by preventing changes in presynaptic and postsynaptic marker proteins and promoting survival pathways also partially via the expression of REST. Our results suggest that REST acts as a novel and important nuclear target for lithium. We hypothesize that PrP106-126-stimulated neurotoxicity induces Wnt signaling dysfunction and lithium mimics this signaling cascade, suggesting that lithium should be considered as a potential therapeutic agent against prion diseases.

Pharmacogenetics of lithium effects on glomerular function in bipolar disorder patients under chronic lithium treatment: a pilot study.

Bipolar disorder (BD) is a psychiatric disease characterized by alternating episodes of mania and depression. Lithium (Li) represents the mainstay treatment for BD, although a significant proportion of patients shows insufficient or no response. Li is also associated with potentially severe side effects, including renal effects. Several studies reported that Li may induce reduction of glomerular filtration rate (GFR) in patients under long-term treatment. The biological systems and the genetic factors involved in susceptibility to Li-induced renal-side effects have been scarcely explored. The aim of our study was to test the contribution of putatively risk genetic variants in Li-induced reduction in estimated GFR (eGFR) in BD patients under long-term Li treatment. Tag SNPs, located in genes previously shown to be associated with kidney dysfunction or Li mechanism of action, were selected and genotyped in a sample of 70 BD patients of Sardinian origin. SNP rs378448, located in Acid Sensing Ion Channel Neurona-1 (ACCN1) gene, showed a significant interaction with duration of Li treatment on eGFR (F2=3.623, p=0.033). Our preliminary findings suggest that rs378448 could predispose BD subjects to a detrimental effect of chronic Li treatment on kidney functioning.

TCF7L2 mediates the cellular and behavioral response to chronic lithium treatment in animal models.

The mechanism of lithium's therapeutic action remains obscure, hindering the discovery of safer treatments for bipolar disorder. Lithium can act as an inhibitor of the kinase GSK3α/ß, which in turn negatively regulates ß-catenin, a co-activator of LEF1/TCF transcription factors. However, unclear is whether therapeutic levels of lithium activate ß-catenin in the brain, and whether this activation could have a therapeutic significance. To address this issue we chronically treated mice with lithium. Although the level of non-phospho-ß-catenin increased in all of the brain areas examined, ß-catenin translocated into cellular nuclei only in the thalamus. Similar results were obtained when thalamic and cortical neurons were treated with a therapeutically relevant concentration of lithium in vitro. We tested if TCF7L2, a member of LEF1/TCF family that is highly expressed in the thalamus, facilitated the activation of ß-catenin. Silencing of Tcf7l2 in thalamic neurons prevented ß-catenin from entering the nucleus, even when the cells were treated with lithium. Conversely, when Tcf7l2 was ectopically expressed in cortical neurons, ß-catenin shifted to the nucleus, and lithium augmented this process. Lastly, we silenced tcf7l2 in zebrafish and exposed them to lithium for 3 days, to evaluate whether TCF7L2 is involved in the behavioral response. Lithium decreased the dark-induced activity of control zebrafish, whereas the activity of zebrafish with tcf7l2 knockdown was unaltered. We conclude that therapeutic levels of lithium activate ß-catenin selectively in thalamic neurons. This effect is determined by the presence of TCF7L2, and potentially contributes to the therapeutic response.

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

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

Sex-specific effects of LiCl treatment on preservation of renal function and extended life-span in murine models of SLE: perspective on insights into the potential basis for survivorship in NZB/W female mice.

Considerable research effort has been invested in attempting to understand immune dysregulation leading to autoimmunity and target organ damage. In systemic lupus erythematosus (SLE), patients can develop a systemic disease with a number of organs involved. One of the major target organs is the kidney, but patients vary in the progression of the end-organ targeting of this organ. Some patients develop glomerulonephritis only, while others develop rapidly progressive end organ failure. In murine models of SLE, renal involvement can also occur. Studies performed over the past several years have indicated that treatment with LiCl of females, but not males of the NZB/W model, at an early age during the onset of disease, can prevent development of end-stage renal disease in a significant percentage of the animals. While on Li treatment, up to 80 % of the females can exhibit long-term survival with evidence of mild glomerulonephritis which does not progress to renal failure in spite of on-going autoimmunity. Stopping the treatment led to a reactivation of the disease and renal failure. Li treatment of other murine models of SLE was less effective and decreased survivorship in male BxSB mice, exhibited little effect on male MRL-lpr mice, and only modestly improved survivorship in female MRL-lpr mice. This perspective piece discusses the findings of several related studies which support the concept that protecting target organs such as the kidney, even in the face of continued immune insults and some inflammation, can lead to prolonged survival with retention of organ function. Some possible mechanisms for the effectiveness of Li treatment in this context are also discussed. However, the detailed mechanistic basis for the sex-specific effects of LiCl treatment particularly in the NZB/W model remains to be elucidated. Elucidating such details may provide important clues for development of effective treatment for patients with SLE, ~90 % of which are females.

Renal microcysts and lithium.

OBJECTIVE: To review the relationship between lithium-related renal dysfunction and microcysts. METHOD: Electronic databases (PubMed and Google Scholar) were queried. RESULTS: From a total of 12,425 publications, 76 were reviewed. DISCUSSION: Glomerular renal dysfunction occurs after an average of 20 years of continuous lithium treatment, and the severity is related to the total lithium load as measured by dose and duration. Recently, several reports have highlighted the relationship between renal microcyst formation and significant reductions in glomerular filtration rate. Radiologically visible lithium-related microcysts are usually 1-2 mm and occasionally 3 mm. Smaller cysts, which are impossible to resolve, are probably more common than the visible cysts, based on observations of renal needle biopsies. Increases in the number of microcysts and the space they occupy within kidney volume appear to be related to both the duration of lithium treatment and the reduction in kidney function. The proposed mechanism of microcyst formation is related to the antiapoptotic effect of lithium. Specifically, by preventing renal tubular epithelial cells from undergoing apoptosis as part of the process of normal renal maintenance, lithium may be allowing the inappropriate growth of the surface area of tubules to form invaginations and ultimately cysts. It is proposed that the physical space occupied by these cysts in the limited volume within the renal capsule compromises the function of otherwise healthy renal tissue. Monitoring of kidneys utilizing radiographic imaging may be more sensitive than monitoring laboratory values. Additional research is required to optimize this new monitoring tool.

No association of endocannabinoid genes with bipolar disorder or lithium response in a Sardinian sample.

Bipolar disorder (BD) is a chronic and severe psychiatric condition with an underlying component of genetic susceptibility. Mounting evidence suggests a potential role of the endogenous cannabinoid (eCB) system in the pathogenesis of BD. Here we investigated the role of genes encoding for key eCB elements on the risk of developing BD in a sample of 357BD patients and 422 healthy controls of Sardinian ancestry. Using the HapMap CEU population SNP database, we selected 25 tag Single Nucleotide Polymorphisms (tSNPs) in N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD), cannabinoid receptor 1 (CNR1) and fatty acid amide hydrolase (FAAH) genes. No significant association was reported for FAAH or CNR1. SNPs rs11487077 and rs6465903 in NAPE-PLD showed nominal association (p=0.033 and p=0.026, respectively) with BD, not significant after permutation testing. These SNPs were also tested for association with lithium response in 204 BD patients characterized for response to long-term lithium treatment, reporting no significant findings. As a whole, our results do not support a clear role of FAAH, CNR1 and NAPE-PLD in BD and lithium response. Additional studies on independent, larger samples are warranted to further explore the involvement of the eCB system in BD.

Xenopus dorsal pattern formation is lithium-sensitive.

Frog embryos that are treated with lithium during cleavage stages produce increased amounts of anterodorsal structures and decreased amounts of posterior and ventral structures. This alteration in pattern formation involves at least two changes in cell fate: the blastomeres that normally produce ventral structures populate anterodorsal structures, and the blastomeres that normally produce posterodorsal structures populate anterodorsal structures. The dorsalization of the ventral mesoderm has been shown to occur because Li alters the response to the ventral component of mesoderm induction. The posterior to anterior changes can be attributed to a reversal of embryonic polarity caused by a marked reduction in the dorsal involution of chordamesoderm. However, it is not known whether the reduction of chordamesodermal involution is produced secondarily by the abnormal migratory properties of the dorsalized ventral mesoderm, or whether it is caused by Li directly. In order to distinguish between these possibilities, chimeras of normal and Li-treated embryos were produced at the beginning of gastrulation. Chimeras with Li-treated ventral halves and normal dorsal halves developed into embryos with two heads and a single normal trunk, confirming the conclusion that the dorsalization of ventral mesoderm is produced directly by the Li. Chimeras with normal ventral halves and Li-treated dorsal halves developed into embryos that lacked postcephalic dorsal structures. These results indicate that the Li-produced lack of postcephalic dorsal structures does not depend on the altered ventral morphogenetic movements. The fate changes on the dorsal side of the embryo suggest that Li also alters the dorsal component of mesoderm induction.