Cannabinoid receptor gene polymorphisms and cognitive performance in patients with schizophrenia and controls

Objective: To test the hypothesis that genetic variations of cannabinoid receptors contribute to the pathophysiology of cognitive deficits in schizophrenia. Methods: In this genetic association case-control study, cannabinoid receptor polymorphisms CNR1 rs12720071 and CNR2 rs2229579 were tested for association with neurocognitive performance in 69 patients with schizophrenia and 45 healthy controls. Neurocognition was assessed by the Brief Assessment of Cognition in Schizophrenia (BACS). Results: We found a consistent association between CNR1 rs12720071 polymorphism and the cognitive performance of patients in several cognitive domains. Patients with C/C polymorphism presented significantly worse performance in motor speed, verbal fluency, attention/processing speed and reasoning/problem solving. Conclusion: Although limited, our data support the hypothesis that CNR1 variations may be associated with the pathogenesis of cognitive deficits of schizophrenia.

Cannabinoid receptor gene polymorphisms and cognitive performance in patients with schizophrenia and controls.

OBJECTIVE: To test the hypothesis that genetic variations of cannabinoid receptors contribute to the pathophysiology of cognitive deficits in schizophrenia. METHODS: In this genetic association case-control study, cannabinoid receptor polymorphisms CNR1 rs12720071 and CNR2 rs2229579 were tested for association with neurocognitive performance in 69 patients with schizophrenia and 45 healthy controls. Neurocognition was assessed by the Brief Assessment of Cognition in Schizophrenia (BACS). RESULTS: We found a consistent association between CNR1 rs12720071 polymorphism and the cognitive performance of patients in several cognitive domains. Patients with C/C polymorphism presented significantly worse performance in motor speed, verbal fluency, attention/processing speed and reasoning/problem solving. CONCLUSION: Although limited, our data support the hypothesis that CNR1 variations may be associated with the pathogenesis of cognitive deficits of schizophrenia.

Cortical volume is inversely correlated with interleukin-6 serum levels in patients with schizophrenia

Introduction: It is well established that cortical volume are decreased in patients with schizophrenia. One possible explanation is that the increased pro-inflammatory status in schizophrenia is related to volumetric decrease of gray matter. The aim of this study was to correlate interleukin 6 (IL-6) with cortical volume in patients with schizophrenia and controls. Methods: We selected 36 patients with schizophrenia and 35 controls. Interleukin 6 (IL-6) was correlated with cortical volume in patients with schizophrenia and controls. Results: IL-6 was negatively correlated with cortical volume (p = 0.027; rho = −0.370) in patients, but not in controls (p = 0.235). Discussion: Our results are in line with previous studies suggesting that chronic inflammatory activation in patients with schizophrenia could be one plausible mechanism that could contribute for the cortical volumetric decrease often seen in this population. However, this cross-sectional study with a small number of patients does not allow us to establish causal relations. (AU)

Aleitamento materno e quimiocinas: diferenças entre esquizofrenia e controles / Breastfeeding and chemokines: differences in schizophrenia and controls

Introdução: Avaliar a associação entre níveis plasmáticos da quimiocina CCL11, coeficiente de inteligência e prática da amamentação em homens com esquizofrenia em condições psiquiátricas estáveis sob acompanhamento ambulatorial em um serviço de saúde pública. Métodos: Foi realizado estudo caso-controle com 60 indivíduos: 30 pacientes com esquizofrenia e 30 controles saudáveis, dos quais 15 de cada grupo foram expostos ao aleitamento materno e 15 não foram. Foi aplicado questionário abordando questões socioeconômicas, história ao nascer, dados clínicos e alimentação ao nascer. Foi dosada a quimiocina CCL11 e aplicados testes psicológicos para avaliar quociente de inteligência, funcionalidade, sintomas psiquiátricos, curso da doença e diagnóstico. Para os controles, foi utilizada uma escala para descartar doença psiquiátrica. Resultados: A quimiocina CCL11 apresentou valores significativamente mais altos (> 0,5) em pacientes com esquizofrenia quando comparados aos controles. No grupo de amamentados, os esquizofrênicos apresentaram valores significativamente mais altos a nível intermediário (entre 0.106 e 0.5). Não houve correlação da CCL11 com o número de hospitalizações, idade, tempo de diagnóstico e escolaridade. Não foi evidenciada correlação entre tempo de aleitamento materno em relação aos fatores do Brief Psychiatric Rating Scale. Houve uma tendência de correlação entre a idade de início da doença e o aleitamento materno. Foi encontrada correlação positiva do CCL11 com o tempo de aleitamento materno. Ao comparar os pacientes esquizofrênicos que foram aleitados com os que não foram, foi encontrada diferença estatisticamente significativa apenas para o quociente de inteligência. Conclusão: O aleitamento materno está associado a níveis mais baixos de CCL11, escores mais altos de quociente de inteligência e a esquizofrenia. A quimiocina CCL11 é mais alta em quem não amamentou, especialmente nos esquizofrênicos. (AU)

Introduction: To evaluate the association between plasma levels of chemokine CCL11, intelligence quotient, and exposure to breastfeeding in men with schizophrenia under stable psychiatric condition and monitored as outpatients in a public health care unit. Methods: A case-control study of 60 individuals, 30 patients with schizophrenia and 30 healthy controls; in each group, 15 were exposed to breastfeeding and 15 were not. A questionnaire addressing socioeconomic issues, history at birth, clinical data, and feeding at birth was administered. Chemokine CCL11 levels were measured, and psychological tests were applied to assess intelligence quotient, functional status, psychiatric symptoms, disease course, and diagnosis. A scale to rule psychiatric illness was used for the controls. Results: Chemokine CCL11 levels were significantly higher (> 0.5) in patients with schizophrenia than in controls. In the breastfed group, patients with schizophrenia also had significantly higher CCL11 levels, but at an intermediate level (between 0.106 and 0.5). There was no correlation between CCL11 and number of hospitalizations, age, time since diagnosis, or level of education, nor between duration of breastfeeding and the Brief Psychiatric Rating Scale factors. A trend toward a correlation was observed between age at disease onset and breastfeeding. There was a positive correlation between CCL11 and duration of breastfeeding. The comparison of patients with schizophrenia who were breastfed vs those who were not breastfed showed a statistically significant difference only in intelligence quotient. Conclusion: Breastfeeding is associated with lower CCL11 levels, higher intelligence quotient scores, and schizophrenia. Chemokine CCL11 levels are higher in those not exposed to breastfeeding, especially in patients with schizophrenia. (AU)

Reduction of hippocampal IL-6 levels in LPS-injected rats following acute exendin-4 treatment.

Preclinical evidence on the role of glucagon-like peptide-1 receptor (GLP-1r) agonists in the brain led to an increased interest in repurposing these compounds as a therapy for central nervous system (CNS) disorders and associated comorbidities. We aimed to investigate the neuroprotective effects of acute treatment with exendin (EX)-4, a GLP-1r agonist, in an animal model of inflammation. We evaluated the effect of different doses of EX-4 on inflammatory, neurotrophic, and oxidative stress parameters in the hippocampus and serum of lipopolysaccharide (LPS)-injected animals. Male Wistar rats were injected with LPS (0.25 mg/kg i.p.) and treated with different doses of EX-4 (0.1, 0.3, or 0.5 µg/kg i.p.). Sickness behavior was assessed by locomotor activity and body weight, and depressive-like behavior was also evaluated using forced swim test (FST). Brain-derived neurotrophic factor (BDNF), thiobarbituric acid reactive species (TBARS), and interleukin (IL)-6 were quantified in the serum and hippocampus. Glycemia was also analyzed pre- and post-EX-4 treatment. LPS groups exhibited decreased frequency of crossing and reduced body weight (p < 0.001), while alterations on FST were not observed. The higher dose of EX-4 reduced IL-6 in the hippocampus of LPS-injected animals (p = 0.018), and EX-4 per se reduced TBARS serum levels with a modest antioxidant effect in the LPS groups (p ≤ 0.005). BDNF hippocampal levels seemed to be increased in the LPS+EX-4 0.5 group compared with LPS+Saline (p > 0.05). Our study provides evidence on acute anti-inflammatory effects of EX-4 in the hippocampus of rats injected with LPS, contributing to future studies on repurposing compounds with potential neuroprotective properties.

Mediator effects of parameters of inflammation and neurogenesis from a N-acetyl cysteine clinical-trial for bipolar depression.

OBJECTIVE: This study aimed to explore effects of adjunctive treatment with N-acetyl cysteine (NAC) on markers of inflammation and neurogenesis in bipolar depression. METHODS: This is a secondary analysis of a placebo-controlled randomised trial. Serum samples were collected at baseline, week 8, and week 32 of the open-label and maintenance phases of the clinical trial to determine changes in interleukin (IL)-6, IL-8, IL-10, tumour necrosis factor-α (TNF-α), C-reactive protein (CRP) and brain-derived neurotrophic factor (BDNF) following adjunctive NAC treatment, and to explore mediation and moderator effects of the listed markers. RESULTS: Levels of brain-derived neurotrophic factor (BDNF), tumour necrosis factor-α (TNF-α), C-reactive protein (CRP), interleukins (IL) -6, 8, or 10 were not significantly changed during the course of the trial or specifically in the open-label and maintenance phases. There were no mediation or moderation effects of the biological factors on the clinical parameters. CONCLUSION: The results suggest that these particular biological parameters may not be directly involved in the therapeutic mechanism of action of adjunctive NAC in bipolar depression.

Telomere Length and CCL11 Levels are Associated With Gray Matter Volume and Episodic Memory Performance in Schizophrenia: Evidence of Pathological Accelerated Aging.

Schizophrenia (SZ) is associated with increased somatic morbidity and mortality, in addition to cognitive impairments similar to those seen in normal aging, which may suggest that pathological accelerated aging occurs in SZ. Therefore, we aim to evaluate the relationships of age, telomere length (TL), and CCL11 (aging and inflammatory biomarkers, respectively), gray matter (GM) volume and episodic memory performance in individuals with SZ compared to healthy controls (HC). One hundred twelve participants (48 SZ and 64 HC) underwent clinical and memory assessments, structural MRI, and had their peripheral blood drawn for biomarkers analysis. Comparisons of group means and correlations were performed. Participants with SZ had decreased TL and GM volume, increased CCL11, and worse memory performance compared to HC. In SZ, shorter TL was related to increased CCL11, and both biomarkers were related to reduced GM volume, all of which were related to worse memory performance. Older age was only associated with reduced GM, but longer duration of illness was related with all the aforementioned variables. Younger age of disease onset was associated with increased CCL11 levels and worse memory performance. In HC, there were no significant correlations except between memory and GM. Our results are consistent with the hypothesis of accelerated aging in SZ. These results may indicate that it is not age itself, but the impact of the disease associated with a pathological accelerated aging that leads to impaired outcomes in SZ.

Shortened telomere length in bipolar disorder: a comparison of the early and late stages of disease

Objective: Bipolar disorder (BD) has been associated with increased rates of age-related diseases, such as type II diabetes, metabolic syndrome, osteoporosis, and cardiovascular disorders. Several biological findings have been associated with age-related disorders, including increased oxidative stress, inflammation, and telomere shortening. The objective of this study was to compare telomere length among participants with BD at early and late stages and age- and gender-matched healthy controls. Methods: Twenty-six euthymic subjects with BD and 34 healthy controls were recruited. Genomic DNA was extracted from peripheral blood and mean telomere length was measured using real-time quantitative polymerase chain reaction. Results: Telomere length was significantly shorter in both the early and late subgroups of BD subjects when compared to the respective controls (p = 0.002 and p = 0.005, respectively). The sample size prevented additional subgroup analyses, including potential effects of medication, smoking status, and lifestyle. Conclusion: This study is concordant with previous evidence of telomere shortening in BD, in both early and late stages of the disorder, and supports the notion of accelerated aging in BD.

Shortened telomere length in bipolar disorder: a comparison of the early and late stages of disease.

OBJECTIVE:: Bipolar disorder (BD) has been associated with increased rates of age-related diseases, such as type II diabetes, metabolic syndrome, osteoporosis, and cardiovascular disorders. Several biological findings have been associated with age-related disorders, including increased oxidative stress, inflammation, and telomere shortening. The objective of this study was to compare telomere length among participants with BD at early and late stages and age- and gender-matched healthy controls. METHODS:: Twenty-six euthymic subjects with BD and 34 healthy controls were recruited. Genomic DNA was extracted from peripheral blood and mean telomere length was measured using real-time quantitative polymerase chain reaction. RESULTS:: Telomere length was significantly shorter in both the early and late subgroups of BD subjects when compared to the respective controls (p = 0.002 and p = 0.005, respectively). The sample size prevented additional subgroup analyses, including potential effects of medication, smoking status, and lifestyle. CONCLUSION:: This study is concordant with previous evidence of telomere shortening in BD, in both early and late stages of the disorder, and supports the notion of accelerated aging in BD.

Telomere length in subjects with schizophrenia, their unaffected siblings and healthy controls: Evidence of accelerated aging.

Schizophrenia (SZ) is associated with broad burden. The clinical manifestations of SZ are related to pathophysiological alterations similar to what is seen in normal aging. Our aim was to evaluate the differences in telomere length (TL), a biomarker of cellular aging, in subjects with SZ (n=36), unaffected siblings (SB, n=36) and healthy controls (HC, n=47). SZ had shorter TL compared to HC, but no difference was found in SB comparing to SZ. These findings indicate that a pathological accelerated aging profile could be present in the course of SZ and further studies are needed to confirm TL as potential endophenotype, especially in at risk populations.

Neurotrophins, inflammation and oxidative stress as illness activity biomarkers in bipolar disorder.

Recent studies highlight the presence of systemic toxicity as an integral dimension of bipolar disorder pathophysiology, possibly linking this mood disorder with other medical conditions and comorbidities. This review summarizes recent findings on possible peripheral biomarkers of illness activity, with a focus on neurotrophins, inflammation and oxidative stress. The possible mechanisms underlying the systemic toxicity associated with acute episodes in bipolar disorder are also discussed. Finally, the authors outline novel therapies that emerge from this new research and the assessment of multiple biomarkers as a potential approach to improving management strategies in bipolar disorder.

Mitochondrial activity and oxidative stress markers in peripheral blood mononuclear cells of patients with bipolar disorder, schizophrenia, and healthy subjects.

Evidence suggests that mitochondrial dysfunction is involved in the pathophysiology of psychiatric disorders such as schizophrenia (SZ) and bipolar disorder (BD). However, the exact mechanisms underlying this dysfunction are not well understood. Impaired activity of electron transport chain (ETC) complexes has been described in these disorders and may reflect changes in mitochondrial metabolism and oxidative stress markers. The objective of this study was to compare ETC complex activity and protein and lipid oxidation markers in 12 euthymic patients with BD type I, in 18 patients with stable chronic SZ, and in 30 matched healthy volunteers. Activity of complexes I, II, and III was determined by enzyme kinetics of mitochondria isolated from peripheral blood mononuclear cells (PBMCs). Protein oxidation was evaluated using the protein carbonyl content (PCC) method, and lipid peroxidation, the thiobarbituric acid reactive substances (TBARS) assay kit. A significant decrease in complex I activity was observed (p = 0.02), as well as an increase in plasma levels of TBARS (p = 0.00617) in patients with SZ when compared to matched controls. Conversely, no significant differences were found in complex I activity (p = 0.17) or in plasma TBARS levels (p = 0.26) in patients with BD vs. matched controls. Our results suggest that mitochondrial complex I dysfunction and oxidative stress play important roles in the pathophysiology of SZ and may be used in potential novel adjunctive therapy for SZ, focusing primarily on cognitive impairment and disorder progression.

Effects of omega-3 dietary supplement in prevention of positive, negative and cognitive symptoms: a study in adolescent rats with ketamine-induced model of schizophrenia.

Omega-3 has shown efficacy to prevent schizophrenia conversion in ultra-high risk population. We evaluated the efficacy of omega-3 in preventing ketamine-induced effects in an animal model of schizophrenia and its effect on brain-derived neurotrophic factor (BDNF). Omega-3 or vehicle was administered in Wistar male rats, both groups at the 30th day of life for 15days. Each group was split in two to receive along the following 7days ketamine or saline. Locomotor and exploratory activities, memory test and social interaction between pairs were evaluated at the 52nd day of life. Prefrontal-cortex, hippocampus and striatum tissues were extracted right after behavioral tasks for mRNA BDNF expression analysis. Bloods for serum BDNF were withdrawn 24h after the end of behavioral tasks. Locomotive was increased in ketamine-treated group compared to control, omega-3 and ketamine plus omega-3 groups. Ketamine group had fewer contacts and interaction compared to other groups. Working memory and short and long-term memories were significantly impaired in ketamine group compared to others. Serum BDNF levels were significantly higher in ketamine plus omega-3 group. There was no difference between groups in prefrontal-cortex, hippocampus and striatum for mRNA BDNF expression. Administration of omega-3 in adolescent rats prevents positive, negative and cognitive symptoms in a ketamine animal model of schizophrenia. Whether these findings are consequence of BDNF increase it is unclear. However, this study gives compelling evidence for larger clinical trials to confirm the use of omega-3 to prevent schizophrenia and for studies to reinforce the beneficial role of omega-3 in brain protection.

Olanzapine plus fluoxetine treatment increases Nt-3 protein levels in the rat prefrontal cortex.

Evidence is emerging for a role for neurotrophins in the treatment of mood disorders. In this study, we evaluated the effects of chronic administration of fluoxetine, olanzapine and the combination of fluoxetine/olanzapine on the brain-derived-neurotrophic factor (BDNF), nerve growth factor (NGF), and neurotrophin-3 (NT-3) in the rat brain. Wistar rats received daily injections of olanzapine (3 or 6 mg/kg) and/or fluoxetine (12.5 or 25mg/kg) for 28 days, and we evaluated for BDNF, NGF and NT-3 protein levels in the prefrontal cortex, hippocampus and amygdala. Our results showed that treatment with fluoxetine and olanzapine alone or in combination did not alter BDNF in the prefrontal cortex (p=0.37), hippocampus (p=0.98) and amygdala (p=0.57) or NGF protein levels in the prefrontal cortex (p=0.72), hippocampus (p=0.23) and amygdala (p=0.64), but NT-3 protein levels were increased by olanzapine 6 mg/kg/fluoxetine 25mg/kg combination in the prefrontal cortex (p=0.03), in the hippocampus (p=0.83) and amygdala (p=0.88) NT-3 protein levels did not alter. Finally, these findings further support the hypothesis that NT-3 could be involved in the effect of treatment with antipsychotic and antidepressant combination in mood disorders.

Maternal deprivation induces depressive-like behaviour and alters neurotrophin levels in the rat brain.

The present study was aimed to evaluate the behavioral and molecular effects of maternal deprivation in adult rats. To this aim, male rats deprived and non-deprived were assessed in the forced swimming and open-field tests in adult phase. In addition adrenocorticotrophin hormone (ACTH) levels was assessed in serum and brain-derived-neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and nerve growth factor (NGF) protein levels were assessed in prefrontal cortex, hippocampus and amygdala. We observed that maternal deprivation increased immobility time, and decreased climbing time, without affecting locomotor activity. ACTH circulating levels were increased in maternal deprived rats. Additionally, BDNF protein levels were reduced in the amygdala and NT-3 and NGF were reduced in both hippocampus and amygdala in maternal deprived rats, compared to control group. In conclusion, our results support the idea that behavioral, ACTH circulating levels and neurotrophins levels altered in maternal deprivation model could contribute to stress-related diseases, such as depression.