Plasmatic endocannabinoids are decreased in subjects with ultra-high risk of psychosis.

The onset of frank psychosis is usually preceded by a prodromal phase characterized by attenuated psychotic symptoms. Currently, research on schizophrenia prodromal phase (ultra-high risk for psychosis [UHR]) has focused on the risk of developing psychosis, on the transition to full blown psychosis and on its prediction. Neurobiological differences between UHR individuals who fully recover (remitters) versus those who show persistent/progressive prodromal symptoms (nonremitters) have been little explored. The endocannabinoid system constitutes a neuromodulatory system that plays a major role in brain development, synaptic plasticity, emotional behaviours and cognition. It comprises two cannabinoid receptors (CB1/CB2), two endocannabinoid ligands, arachidonylethanolamide (AEA) and 2-arachidonoylglycerol (2AG) along with their inactivation enzymes. Despite much evidence that the endocannabinoid system is imbalanced during psychosis, very little is known about it in UHR. Therefore, we aimed to quantify the plasma endocannabinoid levels in UHR and healthy controls (HC) and verify if these metabolites could differentiate between remitters and nonremitters. Circulating concentrations of AEA (p = .003) and 2AG (p < .001) were lower in UHR when compared with HC, with no difference between remitters and nonremitters. Regarding clinical evolution, it was observed that out of 91 UHRs initially considered, 16 had psychiatric complaints (3 years of follow-up). Considering those subjects, there were weak correlations between clinical parameters and plasma concentrations of endocannabinoids. Our results suggest that the endocannabinoids are imbalanced before frank psychosis and that changes can be seen in plasma of UHR individuals. These molecules proved to be potential biomarkers to identify individuals in the prodromal phase of psychosis.

Genetic polymorphisms of the serotonin transporter are not related with depression in temporal lobe epilepsy caused by hippocampal sclerosis.

BACKGROUND: Mood disorders are the most frequent psychiatric disorders in patients with temporal lobe epilepsy caused by hippocampal sclerosis (TLE-HS). The pathophysiological mechanisms in common between TLE and mood disorders include abnormalities in the serotonergic pathway. We aimed to evaluate the association between serotonin transporter genetic polymorphisms - 5-HTTLPR and 5-HTTVNTR - and the presence of mood disorders in patients with TLE-HS. METHODS: We evaluated 119 patients with TLE-HS, with and without psychiatric disorder; 146 patients diagnosed with major depressive disorder (MDD), and 113 healthy volunteers. Individuals were genotyped for the 5-HTTLPR and 5-HTTVNTR polymorphisms. RESULTS: No difference was observed between the TLE-HS groups, healthy controls, and MDD without epilepsy. There was a correlation between the 12-allele of the 5-HTTVNTR and the family history of patients with epilepsy with TLE-HS (p = 0.013). CONCLUSIONS: In this study conducted in two Brazilian centers, the serotonin transporter polymorphisms evaluated cannot be associated with depressive disorder in patients with TLE-HS. Still, they do have some influence over some clinical characteristics of epilepsy in TLE-HS. These data may not be reproduced in other populations with distinct ethnic characteristics.

Increased PLA2 activity in individuals at ultra-high risk for psychosis.

Phospholipase A2 is the main enzyme in the metabolism of membrane phospholipids. It comprises a family of enzymes divided into iPLA2, cPLA2 and sPLA2. Studies have reported increased PLA2 activity in psychotic patients, which suggests an accelerated breakdown of membrane phospholipids. In the present study we investigated whether increased PLA2 activity is also present in individuals at ultra-high risk (UHR) for psychosis. One-hundred fifty adults were included in this study (85 UHR and 65 controls). UHR was assessed using the "structured interview for prodromal syndromes". PLA2 activity was determined in platelets by a radio-enzymatic assay. We found in UHR individuals increased activities of iPLA2 (p < 0.001) and cPLA2 (p = 0.012) as compared to controls. No correlations were found between socio-demographic and clinical parameters and PLA2 activity. Our findings suggest that increased PLA2 activities may be useful as a biological risk-marker for psychotic disorders.

Trial of Electrical Direct-Current Therapy versus Escitalopram for Depression.

BACKGROUND: We compared transcranial direct-current stimulation (tDCS) with a selective serotonin-reuptake inhibitor for the treatment of depression. METHODS: In a single-center, double-blind, noninferiority trial involving adults with unipolar depression, we randomly assigned patients to receive tDCS plus oral placebo, sham tDCS plus escitalopram, or sham tDCS plus oral placebo. The tDCS was administered in 30-minute, 2-mA prefrontal stimulation sessions for 15 consecutive weekdays, followed by 7 weekly treatments. Escitalopram was given at a dose of 10 mg per day for 3 weeks and 20 mg per day thereafter. The primary outcome measure was the change in the 17-item Hamilton Depression Rating Scale (HDRS-17) score (range, 0 to 52, with higher scores indicating more depression). Noninferiority of tDCS versus escitalopram was defined by a lower boundary of the confidence interval for the difference in the decreased score that was at least 50% of the difference in the scores with placebo versus escitalopram. RESULTS: A total of 245 patients underwent randomization, with 91 being assigned to escitalopram, 94 to tDCS, and 60 to placebo. In the intention-to-treat analysis, the mean (±SD) decrease in the score from baseline was 11.3±6.5 points in the escitalopram group, 9.0±7.1 points in the tDCS group, and 5.8±7.9 points in the placebo group. The lower boundary of the confidence interval for the difference in the decrease for tDCS versus escitalopram (difference, -2.3 points; 95% confidence interval [CI], -4.3 to -0.4; P=0.69) was lower than the noninferiority margin of -2.75 (50% of placebo minus escitalopram), so noninferiority could not be claimed. Escitalopram and tDCS were both superior to placebo (difference vs. placebo, 5.5 points [95% CI, 3.1 to 7.8; P<0.001] and 3.2 points [95% CI, 0.7 to 5.5; P=0.01], respectively). Patients receiving tDCS had higher rates of skin redness, tinnitus, and nervousness than did those in the other two groups, and new-onset mania developed in 2 patients in the tDCS group. Patients receiving escitalopram had more frequent sleepiness and obstipation than did those in the other two groups. CONCLUSIONS: In a single-center trial, tDCS for the treatment of depression did not show noninferiority to escitalopram over a 10-week period and was associated with more adverse events. (Funded by Fundação de Amparo à Pesquisa do Estado de São Paulo and others; ELECT-TDCS ClinicalTrials.gov number, NCT01894815 .).

Three plasma metabolites in elderly patients differentiate mild cognitive impairment and Alzheimer's disease: a pilot study.

The metabolomic profile of patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI) may suggest potential diagnostic biomarkers and provide information on the pathophysiology of dementia. Our aim was to quantify plasmatic metabolites of AD patients, MCI and controls. We investigated the metabolomic profile-using the AbsoluteIDQ®p180 assay-of 79 older adults with primary cognitive impairment (34 AD and 20 MCI) and 25 healthy elders (controls). A cluster analysis revealed that a combination C12-DC, C12 and PCaaC26:0 could differentiate the patients according to diagnostic. Future studies should combine metabolomic profiles with other biomarkers to identify diagnostic groups.

Reduced Annexin A3 in schizophrenia.

The cellular and molecular mechanisms underlying onset and development of schizophrenia have not yet been completely elucidated, but the association of disturbed neuroplasticity and inflammation has gained particular relevance recently. These mechanisms are linked to annexins functions. ANXA3, particularly, is associated to inflammation and membrane metabolism cascades. The aim was to determine the ANXA3 levels in first-onset drug-naïve psychotic patients. We investigated by western blot the protein expression of annexin A3 in platelets of first-onset, drug-naïve psychotic patients (diagnoses according to DSM-IV: 28 schizophrenia, 27 bipolar disorder) as compared to 30 age- and gender-matched healthy controls. Annexin A3 level was lower in schizophrenia patients as compared to healthy controls (p < 0.001) and to bipolar patients (p < 0.001). Twenty out of 28 schizophrenic patients had undetectable annexin A3 levels, as compared to none from the bipolar and none from the control subjects. ANXA3 was reduced in drug-naïve patients with schizophrenia. ANXA3 affects neuroplasticity, inflammation and apoptosis, as well as it modulates membrane phospholipid metabolism. All these processes have been discussed in regard to the biology of schizophrenia. In face of these data, we feel that further studies with larger samples are warranted to investigate the possible role of reduced ANXA3 as a possible risk marker for schizophrenia.

Clinical and biological effects of long-term lithium treatment in older adults with amnestic mild cognitive impairment: randomised clinical trial.

BACKGROUND: Experimental studies indicate that lithium may facilitate neurotrophic/protective responses in the brain. Epidemiological and imaging studies in bipolar disorder, in addition to a few trials in Alzheimer's disease support the clinical translation of these findings. Nonetheless, there is limited controlled data about potential use of lithium to treat or prevent dementia. AIMS: To determine the benefits of lithium treatment in patients with amnestic mild cognitive impairment (MCI), a clinical condition associated with high risk for Alzheimer's disease. METHOD: A total of 61 community-dwelling, physically healthy, older adults with MCI were randomised to receive lithium or placebo (1:1) for 2 years (double-blind phase), and followed-up for an additional 24 months (single-blinded phase) (trial registration at clinicaltrials.gov: NCT01055392). Lithium carbonate was prescribed to yield subtherapeutic concentrations (0.25-0.5 mEq/L). Primary outcome variables were the cognitive (Alzheimer's Disease Assessment Scale - cognitive subscale) and functional (Clinical Dementia Rating - Sum of Boxes) parameters obtained at baseline and after 12 and 24 months. Secondary outcomes were neuropsychological test scores; cerebrospinal fluid (CSF) concentrations of Alzheimer's disease-related biomarkers determined at 0, 12 and 36 months; conversion rate from MCI to dementia (0-48 months). RESULTS: Participants in the placebo group displayed cognitive and functional decline, whereas lithium-treated patients remained stable over 2 years. Lithium treatment was associated with better performance on memory and attention tests after 24 months, and with a significant increase in CSF amyloid-beta peptide (Aß1-42) after 36 months. CONCLUSIONS: Long-term lithium attenuates cognitive and functional decline in amnestic MCI, and modifies Alzheimer's disease-related CSF biomarkers. The present data reinforces the disease-modifying properties of lithium in the MCI-Alzheimer's disease continuum. DECLARATION OF INTEREST: None.

Transcranial direct current stimulation (tDCS) for preventing major depressive disorder relapse: Results of a 6-month follow-up.

BACKGROUND: The efficacy of transcranial direct current stimulation (tDCS) as a continuation therapy for the maintenance phase of the depressive episode is low and insufficiently investigated in literature. We investigated whether it could be enhanced by using a more intensive treatment regimen compared to previous reports. METHODS: Twenty-four patients (16 with unipolar depression and eight with bipolar depression) who presented acute tDCS response (≥50% depression improvement in the Hamilton Depression Rating Scale [HDRS]) after receiving 15 tDCS sessions were followed for up to 6 months or until relapse, defined as clinical worsening and/or HDRS > 15. Sessions were performed twice a week (maximum of 48 sessions) over 24 weeks. The anode and the cathode were positioned over the left and right dorsolateral prefrontal cortex (2 mA current, 30 min sessions were delivered). We performed Kaplan-Meier survival analysis and Cox proportional hazards ratios to evaluate predictors of relapse. RESULTS: Out of 24 patients, 18 completed the follow-up period. tDCS treatment was well tolerated. The mean survival duration was 17.5 weeks (122 days). The survival rate at the end of follow-up was 73.5% (95% confidence interval, 50-87). A trend (P = 0.09) was observed for lower relapse rates in nontreatment- vs. antidepressant treatment-resistant patients (7.7% vs. 45.5%, respectively). No differences in efficacy between unipolar and bipolar depression were observed. CONCLUSION: An intensive tDCS treatment regimen consisting of sessions twice a week achieved relatively low relapse rates after a 6-month follow up of tDCS responders, particularly for nontreatment-resistant patients.

Kynurenine is correlated with IL-1ß in plasma of schizophrenia patients.

The etiology of schizophrenia is still unclear. It is well-known that pro-inflammatory cytokines are higher in schizophrenia patients since the first episode psychosis comparing to healthy controls. Inflammatory downstream cascades influence different cellular pathways, like the displacement of the tryptophan (TRP) metabolism to the production of kynurenine (KYN) instead of serotonin, which results in the generation of several neuro and immunoactive metabolites. The aim of this study was to determine TRP, KYN and IL-1ß plasma levels in first-onset schizophrenia (n = 28) and healthy controls (n = 30). The plasmatic levels of TRP and KYN were decreased in schizophrenic patients (p = 0.004 and p = 0.002, respectively), but there was no difference in the ratio of KYN/TRP (p = 0.554) or either in IL-1ß (p = 0.101). Positive correlation was observed between KYN and IL-1ß only in the schizophrenia group (r = 0.461, p = 0.021). And, there was also positive correlation between KYN and Positive and Negative Symptoms Scale (PANSS) (r = 0.395, p = 0.037). There is no correlation between the other analytes and other parameters of PANSS. Although our results of KYN have been different than expected and there was no difference in the KYN/TRP ratio, we observed a positive correlation between IL-1ß and KYN, corroborating findings that pro-inflammatory agents hold up the KYN pathway.

Donepezil effects on cholesterol and oxysterol plasma levels of Alzheimer's disease patients.

Cholesterol is an essential component in the structure and function of cell membranes and has been associated with the major pathological signatures of Alzheimer's disease (AD). To maintain brain cholesterol homeostasis, it is converted into 24(S)-hydroxycholesterol (24OHC) which can be driven through the blood-brain barrier. Several studies have already described a decrease in 24OHC and an increase of 27(S)-hydroxycholesterol (27OHC) in AD, as a reflection of disease burden, the loss of metabolically active neurons and the degree of structural atrophy. It is also well known that peripheral cholesterol is altered in AD patients. However, there are no data regarding effects of AD treatment in this cholesterol pathway. Since a study from our group indicated a significant increase in membrane phospholipid metabolism by donepezil, the aim of this study was to evaluate the effect of short- and long-term donepezil treatment on cholesterol and metabolites 24OHC and 27OHC in plasma of AD patients and in healthy volunteers. At baseline, we found a decrease of 24OHC (p = 0.003) in AD patients. Cholesterol levels increased with donepezil treatment (p = 0.04) but no differences were observed regarding 24OHC and 27OHC. However, these results confirm and extend previous studies demonstrating disturbed cholesterol turnover in Alzheimer's disease.

Increased Brain Lactate During Depressive Episodes and Reversal Effects by Lithium Monotherapy in Drug-Naive Bipolar Disorder: A 3-T 1H-MRS Study.

OBJECTIVE: Mitochondrial dysfunction and energy metabolism impairment are key components in the pathophysiology of bipolar disorder (BD) and may involve a shift from aerobic to anaerobic metabolism. Measurement of brain lactate in vivo using proton magnetic resonance spectroscopy (H-MRS) represents an important tool to evaluate mitochondrial and metabolic dysfunction during mood episodes, as well as to monitor treatment response. To date, very few studies have quantified brain lactate in BD. In addition, no study has longitudinally evaluated lactate using H-MRS during depressive episodes or its association with mood stabilizer therapy. This study aimed to evaluate cingulate cortex (CC) lactate using 3-T H-MRS during acute depressive episodes in BD and the possible effects induced by lithium monotherapy. METHODS: Twenty medication-free outpatients with short length of BD (80% drug-naive) in a current major depressive episode were matched with control subjects. Patients were treated for 6 weeks with lithium monotherapy at therapeutic doses in an open-label trial (blood level, 0.48 ± 0.19 mmol/L). Cingulate cortex lactate was measured before (week 0) and after lithium therapy (week 6) using H-MRS. Antidepressant efficacy was assessed with the 21-item Hamilton Depression Rating Scale as the primary outcome. RESULTS: Subjects with BD depression showed a significantly higher CC lactate in comparison to control subjects. Furthermore, a significant decrease in CC lactate was observed after 6 weeks of lithium treatment compared with baseline (P = 0.002). CC Lactate levels was associated with family history of mood disorders and plasma lithium levels. CONCLUSIONS: This is the first report of increased CC lactate in patients with bipolar depression and lower levels after lithium monotherapy for 6 weeks. These findings indicate a shift to anaerobic metabolism and a role for lactate as a state marker during mood episodes. Energy and redox dysfunction may represent key targets for lithium's therapeutic actions.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of schizophrenia - a short version for primary care.

OBJECTIVE: Schizophrenia is a severe mental disorder and many patients are treated in primary care settings. Apart from the pharmacological management of disease-associated symptoms, the detection and treatment of side effects is of the utmost importance in clinical practice. The purpose of this publication is to offer relevant evidence-based recommendations for the biological treatment of schizophrenia in primary care. METHODS: This publication is a short and practice-oriented summary of Parts I-III of the World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for Biological Treatment of Schizophrenia. The recommendations were developed by the authors and consented by a task force of international experts. Guideline recommendations are based on randomized-controlled trials and supplemented with non-randomized trials and meta-analyses where necessary. RESULTS: Antipsychotics of different chemical classes are the first-line pharmacological treatments for schizophrenia. Specific circumstances (e.g., suicidality, depression, substance dependence) may need additional treatment options. The pharmacological and non-pharmacological management of side effects is of crucial importance for the long-term treatment in all settings of the healthcare system. CONCLUSIONS: This summary of the three available evidence-based guidelines has the potential to support clinical decisions and can improve treatment of schizophrenia in primary care settings.

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.

Glycogen synthase kinase-3ß in patients with bipolar I disorder: results from a prospective study.

OBJECTIVES: The enzyme glycogen synthase kinase-3ß (GSK3ß) is involved in the mechanisms of action of lithium and may play a role in relation to affective states in bipolar disorder. The objectives of the present study were to compare the activity of GSK-3ß (measured as levels of phosphorylated GSK-3ß [p-GSK-3ß]) between patients with bipolar disorder in the euthymic state and healthy control subjects, and to investigate whether GSK-3ß activity varies with affective states in patients with bipolar I disorder. METHODS: In a prospective 6-12-month follow-up study, we investigated state-specific, intraindividual alterations in the activity of GSK-3ß in 60 patients with bipolar I disorder with an acute severe manic index episode and in subsequent euthymic, depressive and manic states and compared this with repeated measurements in healthy control subjects. Data were analyzed using linear mixed-effects models. RESULTS: From baseline to the end of follow-up, blood samples were drawn from the 60 patients during 181 affective states, comprising 60 manic, 11 mixed, 23 depressive, and 87 states of euthymia. A total of 69 blood samples were drawn from 35 healthy control subjects, with two samples from the same subject taken three months apart. In mixed-model analysis, p-GSK-3ß was decreased in the euthymic state of subjects with bipolar disorder compared with healthy control subjects (b=0.63, 95% confidence interval [CI]: 0.42-0.96, P=.03). In addition, p-GSK-3ß varied with affective states, being increased in depressive (b=1.68, 95% CI: 1.08-2.62, P=.02) and mixed (b=2.07, 95% CI: 1.12-3.84, P=.02) states but not in mania compared with euthymia. CONCLUSIONS: The activity of GSK-3ß is altered in euthymic bipolar disorder compared with healthy control subjects and varies with affective states.

Cognitive impairment in late-life bipolar disorder is not associated with Alzheimer's disease pathological signature in the cerebrospinal fluid.

OBJECTIVES: Cognitive impairment is a common feature of late-life bipolar disorder (BD). Yet, there is limited information on the biological mechanisms associated with this process. It is uncertain whether cognitively impaired patients with BD may present the Alzheimer's disease (AD) bio-signature in the cerebrospinal fluid (CSF), defined as a combination of low concentrations of the amyloid-beta peptide (Aß1-42 ) and high concentrations of total tau (T-tau) and tau phosphorylated at threonine 181 (P-tau). In this study, we sought to determine whether cognitive impairment in elderly patients with BD is associated with the AD CSF bio-signature. METHODS: Seventy-two participants were enrolled in the study. The test group comprised older adults with BD and mild cognitive impairment (BD-MCI; n = 16) and the comparison groups comprised patients with dementia due to AD (n = 17), patients with amnestic MCI (aMCI; n = 14), and cognitively healthy older adults (control group; n = 25). CSF samples were obtained by lumbar puncture and concentrations of Aß1-42 , T-tau and P-tau were determined. RESULTS: CSF concentrations of all biomarkers were significantly different in the AD group compared to all other groups, but did not differentiate BD-MCI subjects from aMCI subjects and controls. BD-MCI patients had a non-significant reduction in CSF Aß1-42 compared to controls, but this was still higher than in the AD group. Concentrations of T-tau and P-tau in BD-MCI patients were similar to those in controls, and significantly lower than those in AD. CONCLUSIONS: Cognitively impaired patients with BD do not display the so-called AD bio-signature in the CSF. We therefore hypothesize that cognitive deterioration in BD is not associated with the classical pathophysiological mechanisms observed in AD, i.e., amyloid deposition and hyperphosphorylation of microtubule-associated tau protein.

Lithium activates brain phospholipase A2 and improves memory in rats: implications for Alzheimer's disease.

Phospholipase A2 (Pla2) is required for memory retrieval, and its inhibition in the hippocampus has been reported to impair memory acquisition in rats. Moreover, cognitive decline and memory deficits showed to be reduced in animal models after lithium treatment, prompting us to evaluate possible links between Pla2, lithium and memory. Here, we evaluated the possible modulation of Pla2 activity by a long-term treatment of rats with low doses of lithium and its impact in memory. Wistar rats were trained for the inhibitory avoidance task, treated with lithium for 100 days and tested for perdurability of long-term memory. Hippocampal samples were used for quantifying the expression of 19 brain-expressed Pla2 genes and for evaluating the enzymatic activity of Pla2 using group-specific radio-enzymatic assays. Our data pointed to a significant perdurability of long-term memory, which correlated with increased transcriptional and enzymatic activities of certain members of the Pla2 family (iPla2 and sPla2) after the chronic lithium treatment. Our data suggest new possible targets of lithium, add more information on its pharmacological activity and reinforce the possible use of low doses of lithium for the treatment of neurodegenerative conditions such as the Alzheimer's disease.

Reduced activities of phospholipases A2 in platelets of drug-naïve bipolar disorder patients.

OBJECTIVE: Phospholipases A2 (PLA2 ) comprise a family of hydrolytic enzymes that cleave membrane phospholipids and play a key role in cellular homeostasis. Alterations in enzymatic activity have been hypothesized in bipolar disorder (BD). Recent studies suggest that PLA2 activity in platelets may reflect PLA2 activity in the brain. The aim of this study was to determine PLA2 activity in platelets of BD patients. METHODS: We determined the activity of PLA2 subtypes [extracellular, calcium-dependent PLA2 (sPLA2 ), intracellular, calcium-dependent PLA2 (cPLA2 ), and intracellular, calcium-independent PLA2 (iPLA2 )] by a radioenzymatic method in platelets from 20 patients with BD (15 drug-naïve and five drug-free) and from 16 age- and gender-matched healthy controls. RESULTS: We found that iPLA2 , cPLA2 , and sPLA2 activities were lower in drug-naïve patients with BD when compared to the control group (p = 0.017, p < 0.001, and p < 0.001, respectively). CONCLUSIONS: Reduced PLA2 activity at the early stage of BD may disrupt brain function and increase the risk for the disease. Moreover, epidemiological studies show that patients with BD have a fivefold increased risk for developing Alzheimer's disease. Because patients with Alzheimer's disease also have reduced PLA2 activity, the present finding of reduced PLA2 in the BD group may be related to the risk factor for these individuals developing Alzheimer's disease in advanced age.

Chronic inhibition of brain phospholipase A2 in adult rats impairs the survival of newborn mature neurons in the hippocampus.

Adult neurogenesis occurs in the hippocampal dentate gyrus (DG) and lateral ventricles, and includes cell proliferation and neuronal differentiation, maturation and survival. In vitro studies suggest a role for phospholipase A2 (PLA2) in neuronal differentiation/maturation and survival. This study aimed to investigate the effect of in vivo chronic inhibition of brain PLA2 in adult rats on the number of newborn mature neurons in the DG. Male Wistar rats were injected with BrdU (cell proliferation marker) and 2 weeks later (beginning of neuronal maturation) sham-operated or infused intracerebroventricularly with either vehicle (DMSO in saline) or PLA2 inhibitor (MAFP dissolved in the vehicle) for 14 days via osmotic minipump. The animals were euthanised 28 days post-BrdU and their brains immunostained for BrdU and BrdU plus NeuN (mature neuronal marker) for analysis of surviving cells. MAFP reduced the number of BrdU(+) cells in the ventral DG (p < 0.05 vs. sham; p < 0.01 vs. DMSO) and the number of BrdU(+)NeuN(+) cells in the ventral (p < 0.01 vs. sham and DMSO) and whole DG (p < 0.02 vs. sham and DMSO). There was no effect of MAFP in the dorsal DG. These findings show that chronic PLA2 inhibition in adult rat hippocampus decreases the number of newborn mature neurons in the ventral DG (reflecting in the whole DG), perhaps by impairing neuronal maturation and survival, and suggest that PLA2 inhibition reported in the hippocampus of Alzheimer disease subjects might partly contribute to the neurogenic abnormalities found in the DG in this disease.

Conjugated linoleic acid-enriched butter improved memory and up-regulated phospholipase A2 encoding-genes in rat brain tissue.

Reduced phospholipase A2 (PLA2) activity has been reported in blood cells and in postmortem brains of patients with Alzheimer disease (AD), and there is evidence that conjugated linoleic acid (CLA) modulates the activity of PLA2 groups in non-brain tissues. As CLA isomers were shown to be actively incorporated and metabolized in the brains of rats, we hypothesized that feeding a diet naturally enriched in CLA would affect the activity and expression of Pla 2 -encoding genes in rat brain tissue, with possible implications for memory. To test this hypothesis, Wistar rats were trained for the inhibitory avoidance task and fed a commercial diet (control) or experimental diets containing either low CLA- or CLA-enriched butter for 4 weeks. After this period, the rats were tested for memory retrieval and killed for tissue collection. Hippocampal expression of 19 Pla 2 genes was evaluated by qPCR, and activities of PLA2 groups (cPLA2, iPLA2, and sPLA2) were determined by radioenzymatic assay. Rats fed the high CLA diet had increased hippocampal mRNA levels for specific PLA2 isoforms (iPla 2 g6γ; cPla 2 g4a, sPla 2 g3, sPla 2 g1b, and sPla 2 g12a) and higher enzymatic activity of all PLA2 groups as compared to those fed the control and the low CLA diet. The increment in PLA2 activities correlated significantly with memory enhancement, as assessed by increased latency in the step-down inhibitory avoidance task after 4 weeks of treatment (rs = 0.69 for iPLA2, P < 0.001; rs = 0.81 for cPLA2, P < 0.001; and rs = 0.69 for sPLA2, P < 0.001). In face of the previous reports showing reduced PLA2 activity in AD brains, the present findings suggest that dairy products enriched in cis-9, trans-11 CLA may be useful in the treatment of this disease.

Increased plasma levels of soluble TNF receptors 1 and 2 in bipolar depression and impact of lithium treatment.

OBJECTIVE: TNF system (TNF and its soluble receptors sTNFR1 and 2) has been investigated as a potential molecular target in bipolar disorder. The aim of the study was to compare plasma levels of these receptors in unmedicated bipolar depressed patients compared with healthy controls, and to evaluate the effects of a 6-week lithium treatment on sTNFR1 and sTNFR2 levels. METHODS: The study enrolled 29 patients with unmedicated bipolar disorder in a major depressive episode and 27 matched controls. Patients had blood collected at baseline and after 6 weeks of lithium treatment. The concentration of sTNFRs was measured by ELISA. RESULTS: sTNFR1 and sTNFR2 levels were significantly increased in bipolar depression in comparison with healthy subjects. Lithium treatment did not significantly change sTNFR1 and sTNFR2 levels from baseline to endpoint. There was no correlation between improvement in depressive symptoms and the change in sTNFR1 or sTNFR1 levels. CONCLUSION: These results reinforce the involvement of an activated immune response system in the pathophysiology of bipolar disorder, with no impact of lithium treatment on the related biomarkers.