Luis Valmor Cruz Portela

Decreased Plasma Brain Derived Neurotrophic Factor Levels in Unmedicated Bipolar Patients During Manic Episode

BACKGROUND Bipolar disorder (BD) has been increasingly associated with abnormalities in neuroplasticity and cellular resilience. Brain Derived Neurotrophic Factor (BDNF) gene has been considered an important candidate marker for the development of bipolar disorder and this neurotrophin seems involved in intracellular pathways modulated by mood stabilizers. Also, previous studies demonstrated a role for BDNF in the pathophysiology and clinical presentation of mood disorders. METHODS We investigated whether BDNF levels are altered during mania. Sixty subjects (14 M and 46 F) were selected and included in the study. Thirty patients meeting SCID-I criteria for manic episode were age and gender matched with thirty healthy controls. Young Mania Rating Scale (YMRS) evaluated the severity of manic episode and its possible association with the neurotrophin levels. RESULTS Mean BDNF levels were significantly decreased in drug free/naive (224.8 +/- 76.5 pg/ml) compared to healthy controls (318.5 +/- 114.2), p < .001]. Severity of the manic episode presented a significant negatively correlation to plasma BDNF levels (r= .78; p < .001; Pearson test). CONCLUSIONS Overall, these results suggest that the decreased plasma BDNF levels may be directly associated with the pathophysiology and severity of manic symptoms in BD. Further studies are necessary to clarify the role of BDNF as a putative biological marker in BD.

Neuron-Specific Enolase, S100B, and Glial Fibrillary Acidic Protein Levels as Outcome Predictors in Patients With Severe Traumatic Brain Injury

BACKGROUND:The availability of markers able to provide an early insight related to prognostic and functional outcome of patients with traumatic brain injury (TBI) are limited. OBJECTIVE:The relationship of clinical outcome with CSF neuron-specific enolase (NSE), S100B and glial fibrillary acidic protein (GFAP) levels in patients with severe TBI was investigated. METHODS:Twenty patients with severe TBI (7 days at unit care) and controls were studied. Patients were grouped according to the outcome: (1) nonsurvival (n = 5): patients who died; (2) survival A (n = 15): CSF sampled between 1st and 3rd day from patients who survived after hospital admission; and (3) survival B (n = 7): CSF sampled between 4th and 7th day from patients who survived after hospital admission and were maintained with intraventricular catheter up to 7 days. RESULTS:Up to 3 days, S100B and NSE levels (ng/mL) were significantly elevated in the nonsurvival compared with survival A group (S100: 12.45 ± 5.46 vs 5.64 ± 3.36; NSE: 313.20 ± 45.51 vs 107.80 ± 112.10). GFAP levels did not differ between groups. In the survival B group S100B, GFAP, and NSE levels were still elevated compared with control (4.59 ± 2.19, 2.48 ± 2.55, and 89.80 ± 131.10, respectively). To compare S100B and NSE for the prediction of nonsurvival and survival patients we performed receiver operating characteristic curves. At admission, CSF NSE level predicts brain death more accurately than S100B. CONCLUSION:Early elevations (up to 3 days) of S100B and NSE secondary to severe TBI predict deterioration to brain death. However, this feature was more prominently associated with NSE than S100B.

Lithium increases plasma brain-derived neurotrophic factor in acute bipolar mania: a preliminary 4-week study.

Several studies have suggested an important role for brain-derived neurotrophic factor (BDNF) in the pathophysiology and therapeutics of bipolar disorder (BPD). The mechanisms underlying the therapeutic effects of lithium in BPD seem to involve a direct regulation of neurotrophic cascades. However, no clinical study evaluated the specific effects of lithium on BDNF levels in subjects with BPD. This study aims to investigate the effects of lithium monotherapy on BDNF levels in acute mania. Ten subjects with bipolar I disorder in a manic episode were evaluated at baseline and after 28 days of lithium therapy. Changes in plasma BDNF levels and Young Mania Rating Scale (YMRS) scores were analyzed. A significant increase in plasma BDNF levels was observed after 28 days of therapy with lithium monotherapy (510.9±127.1pg/mL) compared to pre-treatment (406.3±69.5pg/mL) (p=0.03). Although it was not found a significant association between BDNF levels and clinical improvement (YMRS), 87% of responders presented an increase in BDNF levels after treatment with lithium. These preliminary data showed lithiums direct effects on BDNF levels in bipolar mania, suggesting that short-term lithium treatment may activate neurotrophic cascades. Further studies with larger samples and longer period may confirm whether this biological effect is involved in the therapeutic efficacy of lithium in BPD.

Serum levels of S100B and NSE proteins in Alzheimer's disease patients

BackgroundAlzheimers disease is the most common dementia in the elderly, and the potential of peripheral biochemical markers as complementary tools in the neuropsychiatric evaluation of these patients has claimed further attention.MethodsWe evaluated serum levels of S100B and neuron-specific enolase (NSE) in 54 mild, moderate and severe Alzheimers disease (AD) patients and in 66 community-dwelling elderly. AD patients met the probable NINCDS-ADRDA criteria. Severity of dementia was ascertained by the Clinical Dementia Rating (CDR) scale, cognitive function by the Mini Mental State Examination (MMSE), and neuroimage findings with magnetic resonance imaging. Serum was obtained from all individuals and frozen at -70°C until analysis.ResultsBy comparing both groups, serum S100B levels were lower in AD group, while serum NSE levels were the same both groups. In AD patients, S100B levels were positively correlated with CDR scores (rho = 0.269; p = 0.049) and negatively correlated with MMSE scores (rho = -0.33; P = 0.048). NSE levels decreased in AD patients with higher levels of brain atrophy.ConclusionsThe findings suggest that serum levels of S100B may be a marker for brain functional condition and serum NSE levels may be a marker for morphological status in AD.

Exercise affects glutamate receptors in postsynaptic densities from cortical mice brain

Physical activity has been proposed as a behavior intervention that promotes mental health and some of the benefits induced by exercise have been related to the glutamatergic system. Indeed, glutamate is the most abundant excitatory neurotransmitter in brain. Thus, we evaluated if voluntary exercise in mice could modulate glutamatergic synapses at level of postsynaptic density (PSD). Through Western blot, we found that exercise during 1 month increased glutamatergic-related protein content in PSD from cortex of mice. Exercise increased the immunocontent of GluR1 (129%), SAP-97 (179%), GRIP-1 (129%), and in less extent, GluR2/3 (118%) and PSD-95 (112%) proteins. The overall content of NMDA subunits R1, R2A and R2B were not altered in mice that had exercised, however, the phosphorylated NMDA subunits, phospho-NMDAR1 (150%), and phospho-NMDAR2B (183%) showed a strong increase. Because exercise increased the content of phosphorylated forms of NMDA receptors, we evaluated the binding of MK-801, a specific ligand that binds to open NMDA channel. Exercise increased the binding of MK-801 in cortical cellular membranes in 51%. Altogether, our results point to a modulation of glutamatergic synapses by exercise with likely implications in the exercise-induced mental health.

Decreased S100-beta protein in schizophrenia: preliminary evidence

The S100 proteins are a family of calcium-binding proteins found in the central and peripheral nervous systems of vertebrates. S100beta, the most abundant member of this family in the CNS, mediates calcium signal transduction, and shows neurotrophic, gliotrophic and mitogenic actions that influence the development and maintenance of the nervous system. Another member of the S100 family (S100A10) was found to modulate phospholipid turnover by inhibiting the activity of enzyme phospholipase A2 (PLA2). We determined the concentration of S100beta protein in the plasma of 23 medicated schizophrenic patients and 23 healthy controls. S100beta protein accounts for 96% of the total S100 in the brain. Schizophrenic patients showed reduced S100beta concentrations (p=0.003), and this finding was not related to clinical variables or to intake of antipsychotic medication. Decreased S100beta could be related to the findings of increased PLA2 activity and to brain maldevelopment in schizophrenia. These results are discussed further with respect to the role of adenosine in S100beta release.

Exercise Increases Insulin Signaling in the Hippocampus: Physiological Effects and Pharmacological Impact of Intracerebroventricular Insulin Administration in Mice

Increasing evidence indicates that physical exercise induces adaptations at the cellular, molecular, and systemic levels that positively affect the brain. Insulin plays important functional roles within the brain that are mediated by insulin‐receptor (IR) signaling. In the hippocampus, insulin improves synaptic plasticity, memory formation, and learning via direct modulation of GABAergic and glutamatergic receptors. Separately, physical exercise and central insulin administration exert relevant roles in cognitive function. We here use CF1 mice to investigate (i) the effects of voluntary exercise on hippocampal insulin signaling and memory performance and (ii) whether central insulin administration alters the effects of exercise on hippocampal insulin signaling and memory performance. Adult mice performed 30 days of voluntary exercise on running wheel and afterward both, sedentary and exercised groups, received intracerebroventricular (icv) injection of saline or insulin (0.5–5 mU). Memory performance was assessed using the inhibitory avoidance and water maze tasks. Hippocampal tissue was measured for [U‐14C] glucose oxidation and the immunocontent of insulin receptor/signaling (IR, pTyr, pAktser473). Additionally, the phosphorylation of the glutamate NMDA receptor NR2B subunit and the capacity of glutamate uptake were measured, and immunohistochemistry was used to determine glial reactivity. Exercise significantly increased insulin peripheral sensitivity, spatial learning, and hippocampal IR/pTyrIR/pAktser473 immunocontent. Glucose oxidation, glutamate uptake, and astrocyte number also increased relative to the sedentary group. In both memory tasks, 5 mU icv insulin produced amnesia but only in exercised animals. This amnesia was associated a rapid (15 min) and persistent (24 h) increase in hippocampal pNR2B immunocontent that paralleled the increase in glial reactivity. In conclusion, physical exercise thus increased hippocampal insulin signaling and improved water maze performance. Overstimulation of insulin signaling in exercised animals, however, via icv administration impaired behavioral performance. This effect was likely the result of aberrant phosphorylation of the NR2B subunit.

Effects of chronic administered guanosine on behavioral parameters and brain glutamate uptake in rats

Oral and intraperitoneal administration of the nucleoside guanosine have been shown to prevent quinolinic acid‐ (QA) and α‐dendrotoxin‐induced seizures, impair memory, and impair anxiety in rats and mice. We investigated the effect of 2‐weeks ad lib orally administered guanosine (0.5 mg/ml) on seizures induced by QA, inhibitory avoidance memory, and locomotor performance in rats. We also studied the mechanism of action of guanosine through the measurement of its concentration in the cerebrospinal fluid (CSF) and its effect on glutamate uptake in cortical slices of rats. QA produced seizures in 85% of rats, an effect partially prevented by guanosine (53% of seizures; P = 0.0208). Guanosine also impaired retention on the inhibitory avoidance task (P = 0.0278) and decreased locomotor activity on the open field test (P = 0.0101). The CSF guanosine concentration increased twofold in the treated group compared to that in the vehicle group (P = 0.0178). Additionally, QA promoted a 30% decrease in glutamate uptake as compared to that with intracerebroventricular saline administration, an effect prevented by guanosine in animals protected against QA‐induced seizures. Altogether, these findings suggest a potential role of guanosine for treating diseases involving glutamatergic excitotoxicity such as epilepsy. These effects seem to be related to modulation of glutamate uptake.

Developmental Changes in S100B Content in Brain Tissue, Cerebrospinal Fluid, and Astrocyte Cultures of Rats

Abstract1. We investigated the content of S100B protein by ELISA in three brain regions (hippocampus, cerebral cortex, and cerebellum) and in cerebrospinal fluid of rats during postnatal development as well as the content and secretion of S100B in pre- and postconfluent primary astrocyte cultures.2. An accumulation of S100B occurred in all brain regions with similar ontogenetic pattern between second and fourth postnatal weeks. However, we observed a decrease in the cerebrospinal fluid S100B after the critical period for synaptogenesis in rodents.3. A similar profile of cell accumulation and decrease in basal secretion was also observed during aging of astrocyte cultures.4. These data contribute to the proposal that S100B is an important glial-derived protein during brain development and that changes in extracellular levels of S100B may be related to glial proliferation and synaptogenesis.

Enriched environment effects on behavior, memory and BDNF in low and high exploratory mice.

Environmental enrichment (EE) has been largely used to investigate behavioral modifications and neuroplasticity in the adult brain both in normal and pathological conditions. The interaction between individual behavioral traits with EE responsiveness has not been investigated within the same strain. By using two extremes of CF1 mice that differ by their exploratory behavior in the Open Field (OF) task (Kazlauckas V, 2005), denominated as Low (LE) and High (HE) Exploratory Mice, the present study evaluated if EE during adulthood could modify the putative differences between LE and HE mice on exploratory behavior, memory performance and hippocampal BDNF levels. To this end, we investigated the effect of adult LE and HE mice after 2 months of enriched or standard housing conditions on the open field, on novel object recognition, on the inhibitory avoidance task and on hippocampal BDNF immunocontent. LE showed low exploratory behavior, less retention in the inhibitory avoidance and lower hippocampal BDNF levels. EE enhanced exploratory behavior, memory performance and hippocampal BDNF levels both in LE and HE mice. Importantly, the general profile of LE mice submitted to EE was similar to HE mice housed in standard conditions. These results show that internalized behavior of LE mice can be significantly modified by exposure to an enriched environment even during adulthood. These observations may contribute to investigate biological mechanisms and therapeutical interventions for individuals with internalized psychiatric disorders.