Decreased serum BDNF levels in chronic institutionalized schizophrenia on long-term treatment with typical and atypical antipsychotics

Accumulating evidence showed that brain-derived neurotrophic factor (BDNF) may be involved in the pathophysiology of schizophrenia. Decreased BDNF levels have been found in the serum of schizophrenic patients with mixed results. In the present study, we assessed serum BDNF levels in a large group of 364 schizophrenic patients (157 on clozapine, 89 on risperidone and 118 on typical antipsychotics), compared to 323 healthy control subjects matched for age and gender. The schizophrenia symptomatology was assessed by the Positive and Negative Syndrome Scale (PANSS), and serum BDNF levels were measured by sandwich ELISA. The results showed that BDNF levels were significantly lower in chronic patients with schizophrenia than in healthy control subjects (9.9 ± 2.0 ng/ml vs.11.9 ± 2.3 ng/ml, p < 0.0001). Lower BDNF levels were observed in patients treated with risperidone (9.3 ± 2.3 ng/ml) compared to those with clozapine (10.2 ± 2.0 ng/ml, p < 0.001) and typical antipsychotics (10.0 ± 2.1 ng/ml, p < 0.01). Furthermore, a stepwise multiple regression analysis identified types of antipsychotic drugs (beta = − 0.37, t = − 3.15, p = 0.001) and BDNF levels (beta = − 0.26, t = − 2.51, p = 0.014) as the influencing factor for the positive symptom subscore of PANSS. In addition, there was a sex difference in BDNF levels in patients with schizophrenia (9.7 ± 1.9 ng/ml for males vs.10.4 ± 2.1 ng/ml for female, p < 0.005), but not in normal controls. Our findings indicated decreased BDNF serum levels in chronic patients with schizophrenia, which may be related to clinical phenotypes, including gender, antipsychotic treatment and the severity of psychotic symptoms.     

Increased plasma levels of thioredoxin-1 in patients with first episode psychosis and long-term schizophrenia

Excessive level of radicals and/or dysfunctional antioxidant response, oxidative stress, is implicated in the pathogenesis of schizophrenia. A condition of oxidative stress has been detected in the brain, peripheral tissues and fluids including plasma. Plasma thioredoxin-1 (Trx1) is well characterized and a putative marker for oxidative stress and recently shown to be increased in plasma at the onset of schizophrenia.The present study aimed to explore whether Trx1 can be used as a marker to identify schizophrenic patients at the time-point when patients have their first episode of psychosis as compared to patients with long-term schizophrenia and mentally healthy patients, respectively.Plasma samples obtained from 18 patients at first episode of psychosis, from 49 long-term schizophrenic patients and from 20 mentally healthy controls (admitted with minor physical injury to the general ward) where analyzed by ELISA for Trx1. The patients with first episode of psychosis were diagnosed at least 6 months later and shown to constitute various psychotic syndromes, including schizophrenia, or affective disorder.The concentration of Trx1 in the patients with first episode of psychosis was 1.5 ± 1.0 ng/ml and 0.8 ± 0.6 ng/ml in controls. In the long-term schizophrenic patients the plasma concentration was 1.5 ± 0.7. The differences between the groups of acute psychotic or long-term schizophrenia patients to controls were significant (p < 0.016 and p < 0.001, respectively).Our data indicate that Trx1 may not be used as an early marker to identify schizophrenic patients in a mixed population of first episode psychotic patients. Further, Trx1 did not discriminate with reliable accuracy patients with psychotic disorder from mentally healthy controls on an individual basis due to overlap in levels of Trx1. However, our observations show that psychotic patients in general are in a significant long-term condition of oxidative stress, with possible implications for the profound morbidity and mortality found in this patient population.     

The effect of smoking status on the plasma concentration of prolactin already elevated by risperidone treatment in schizophrenia patients

Smoking prevalence for schizophrenic patients is higher than for the general population. Inter-individual variability in hyperprolactinemia induced antipsychotics particularly risperidone can be explained by smoking status to some extent. We therefore studied the effects of smoking status on the plasma concentration of prolactin. Subjects included 154 schizophrenia patients (61 males, 93 females) who had received 3 mg of risperidone twice daily for at least 4 weeks. Sample collections were conducted 12 h after the bedtime dosing. The plasma concentrations of prolactin in the females were significantly higher than in the males (117.6 ± 69.3 ng/ml vs. 52.9 ± 30.7 ng/ml, p < 0.001). The mean (± SD) plasma concentrations of prolactin did not differ between smokers and nonsmokers in the males (59.5 ± 31.2 ng/ml vs. 47.6 ± 29.3 ng/ml, not significant (ns)), but there was a significant difference in the females (100.2 ± 59.1 vs. 134.0 ± 74.6, ng/ml, p < 0.05). Multiple regression analyses including gender, plasma drug concentration and age revealed that the plasma concentration of prolactin positively correlated with gender (standardized beta = 0.452, p < 0.001) and negatively with age (standardized beta = −0.171, p < 0.05) and smoking status (standardized beta = −0.232, p < 0.01). These findings suggest that smoking status has an impact on prolactin concentration during risperidone treatment. However, further study is required to determine whether these findings have clinical implications.     

Adjunctive treatment of bimodal repetitive transcranial magnetic stimulation (rTMS) in pharmacologically non-responsive patients with schizophrenia: a preliminary study

Objectives

We evaluated the efficacy of bimodal repetitive transcranial magnetic stimulation (rTMS) in treating pharmacologically non-responsive patients with schizophrenia.

Methods

Ten patients with DSM-IV schizophrenia, unresponsive to pharmacological treatment, underwent treatment with 15 rTMS sessions, as an adjunctive therapy, for three weeks. Each session comprised 40 trains, beginning every 30 s: 20 trains of 10 Hz rTMS to the left dorsolateral prefrontal cortex (DLPFC) with a 3-s duration and 20 trains of 1 Hz rTMS to the left temporoparietal cortex (TPC) with a 30-s duration. We assessed patients via the Positive and Negative Syndrome Scale (PANSS) and Korean Version of the Calgary Depression Scale for Schizophrenia (K-CDSS), at five time points: baseline, Days 8, 15, and 22, and 1 week after final treatment (Day 29). Patients who agreed to take neurocognitive tests underwent neurocognitive function evaluations at baseline and 1 week after final treatment.

Results

At Day 29, all PANSS subscale scores in had decreased significantly compared to baseline (Z = − 2.214, p = 0.027, positive; Z = − 2.132, p = 0.033, negative; Z = − 2.023, p = 0.043, general pathology; Z = − 2.371, p = 0.018, total). Effect over time was significant for the PANSS positive and negative subscale scores and total score (χ² = 13.35, p = 0.010; χ² = 10.27, p = 0.036; and χ² = 16.50, p = 0.002, respectively) but not for the general pathology subscale. Among the neurocognitive tests, the fourth and fifth trials and total K-AVLT scores showed significant increases (Z = − 2.041, p = 0.041; Z = − 2.251, p = 0.024; and Z = − 2.201, p = 0.028, respectively), suggesting improvement in short-term auditory verbal memory.

Conclusions

Bimodal rTMS stimulation of left DLPFC and left TPC induced clinical improvement in pharmacologically non-responsive schizophrenia patients and may have improved their short-term verbal memories.     

Obsessive compulsive disorder and symptoms may have different effects on schizophrenia

The aim of this study is to investigate the possible different effects of obsessive compulsive disorder (OCD) and obsessive compulsive symptoms (OCS) on schizophrenia illness in regard to clinical characteristics such as severity of symptomatology.We included 184 patients with schizophrenia on monotherapy with a stable dose of antipsychotics for at least three months. Severity of clinical symptoms was evaluated by Positive and Negative Syndrome Scale. OCS was examined by Yale-Brown Obsessive Compulsive Scale (Y-BOCS) Checklist. We also assessed OCD by using Y-BOCS.Seventeen percent of the patients were diagnosed with current OCD, while 17.4% of the patients were found to have OCS without OCD. Age of onset for OCD group was earlier than non-OCS group (p = 0.007).The rate of occupation was higher (p = 0.001), prevalence of other comorbid psychiatric disorders was lower (p = 0.05), number of hospitalization was lower (p = 0.03), GAF score was higher (p = 0.03) and duration of education was longer (p = 0.02) in the OCS group than in the non-OCS group. The rate of occupation was higher (p = 0.04) and that rate of comorbid psychiatric disorders was lower (p = 0.01) in the OCS group than in the OCD group. We found more OCS in patients using atypical antipsychotics (p = 0.03).Our findings suggest that OCD and OCS might have different effects on schizophrenia.     

Higher serum clozapine level is associated with increased antiphospholipid antibodies in schizophrenia patients

Objectives

This study was to evaluate the relationship between clozapine and aPL in schizophrenia patients.

Methods

163 Participants were evaluated: 37 unmedicated schizophrenia patients, 50 clozapine-treated schizophrenia patients and 76 age- and sex-matched healthy controls. A fasting blood sample was taken for serum aPL and serum clozapine level. Serum aPL were measured by ELISA technique and HPLC method was used for the determination of serum clozapine level.

Results

The unmedicated schizophrenia patients showed higher IgG aCL level [mean ± SD: 1.51 ± 0.81 and 1.25 ± 0.13 U, respectively (t = 2.77, df=111, p<0.01)] and IgM aCL level [mean±SD: 1.53 ± 0.54. and 1.33 ± 0.15 U, respectively (t = −2.98, df = 111, p < 0.01)] compared with the healthy controls. The comparison of the clozapine-treated schizophrenia patients and the healthy controls showed significant difference in IgG aCL level [mean ± SD: 1.74 ± 0.90 and 1.25 ± 0.13 U, respectively (t = −4.77, df = 124, p < 0.01)] and IgM aCL level [mean ± SD: 1.62 ± 0.83 and1.33 ± 0.15 U, respectively (t = −4.35, df = 124, p < 0.01)]. In clozapine-treated schizophrenia patients, the results of Pearson correlation coefficients showed that there was a significant positive relationship between serum IgM aCL and serum clozapine level (r = 0.461, p < 0.01), and serum IgG aCL were significantly correlated with serum IgM aCL (r = 0.279, p < 0.05). Stepwise multiple regression analysis was performed with various characteristics, such as duration of medication, daily dose and serum clozapine level as candidate factors for serum aCL (IgG and IgM isotypes) in clozapine-treated schizophrenia patients. Only serum clozapine level was able to enter into the regression model of IgM aCL (Model R² = 0.212, p < 0.05).

Conclusions

A higher serum clozapine level is associated with an increased aPL in schizophrenia patients.     

Plasma total antioxidant status and cognitive impairments in schizophrenia

Oxidative stress-induced damage to neurons may contribute to cognitive deficits during aging and in neurodegenerative disorders. Schizophrenia has a range of cognitive deficits that may evolve from oxidative stress, and this study examines this association of oxidative stress with cognitive deficits in schizophrenia. We recruited 296 chronic schizophrenia patients and 181 healthy control subjects and examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and plasma total antioxidant status (TAS) in both groups. Schizophrenia symptoms were assessed using the positive and negative syndrome scale (PANSS). Our results showed that TAS levels were significantly lower in patients than controls (179.6 ± 81.0 U/ml vs. 194.8 ± 46.0 U/ml, p<0.05). Cognitive scores on the RBANS and nearly all of its five subscales (all p<0.001) except for the Visuospatial/Constructional index (p>0.05) were significantly lower in schizophrenia patients than normal controls. For the patients, TAS was inversely associated with some domains of cognitive deficits in schizophrenia, such as Attention and Immediate Memory. Our findings suggest that oxidative stress may be involved in the pathophysiology of schizophrenia, and its associated cognitive impairment.     

Elevated plasma superoxide dismutase in first-episode and drug naive patients with schizophrenia: inverse association with positive symptoms

Excessive free radical production or oxidative stress may be involved in the pathophysiology of schizophrenia as evidenced by increased superoxide dismutase (SOD) activities, a critical enzyme in the detoxification of superoxide radicals. This study compared plasma SOD activities in 78 never-medicated first-episode and 100 medicated chronic schizophrenia patients to 100 healthy control subjects and correlated these SOD activities with the Positive and Negative Syndrome Scale (PANSS) among the schizophrenic patients. We found that both first-episode and chronic patients had significantly increased plasma SOD activities compared to controls, and that chronic schizophrenic patients on antipsychotic medication had significantly higher SOD activities than first episode schizophrenic patients. Plasma SOD activities were also negatively correlated with positive symptoms of schizophrenia, but only in first-episode patients. Thus, oxidative stress appears to be greater in first episode schizophrenic patients with fewer positive symptoms and may become greater as schizophrenia becomes more chronic, although we cannot exclude the possibility that chronic antipsychotic treatment may increase SOD activities and presumed oxidative stress in schizophrenia.     

Dkk3 levels in patients with myeloproliferative neoplasms

Introduction

Dickkopf-3 (Dkk3) has been proposed as tumor suppressor gene and a marker for tumor blood vessels and has pro-angiogenic properties. Dkk3 is expressed in platelets and megakaryocytes from healthy controls and patients with BCR-ABL1-negative myeloproliferative neoplasms (MPN). The aim of this study is, to find out whether patients with MPN have higher Dkk3 serum levels than normal controls.

Material & methods

We analyzed Dkk3 serum levels with ELISA in patients with newly diagnosed and untreated MPN, including 10 essential thrombocythemia (ET), 10 polycythemia vera (PV), 10 primary meylofibrosis (PMF) and 10 healthy blood donors and correlated these findings with biological and clinical key data and the JAK2-V617F status. Dkk3 levels were corrected to platelet count, Dkk3c, as patients with MPN have higher platelet counts than controls.

Results

As expected, patients with MPN have higher platelet counts than normal controls. Dkk3 serum levels of patients with MPN (5.4 ± 6.1 ng/ml) showed no significant difference compared to normal controls (4.4 ± 3.8 ng/ml). Regarding Dkk3c, a significant difference to controls was found in PV (8.5 ± 8.7 ng/ml; p = 0.04), but not in ET and PMF (5.7 ± 3.8 ng/ml; p = 0.07 and 2.7 ± 3.6 ng/ml; p = 0.9; respectively. Dkk3c correlated with the JAK2-V617F mutational burden (p = 0.014, Rho = 0.445).

Conclusion

Dkk3 levels corrected to platelet count showed higher levels in PV than normal controls. Elevated Dkk3c level could possibly correlate to platelet activation in PV patients and increased Dkk3 release. Whether this remains a surrogate marker of platelet release or it contributes to the thrombophilic state through its pro-angiogenic properties remains to be shown.     

Activated protein C plasma levels in the fasting and postprandial states among patients with previous unprovoked venous thromboembolism

Introduction

The protein C anticoagulant system is of major importance in the regulation of thrombotic risk, but it is not known whether low plasma levels of activated protein C (APC) in vivo reflect a compromised anticoagulant situation with increased thrombotic risk. Previous studies have reported low, normal or increased plasma APC levels in unselected patients with venous thromboembolism (VTE).

Materials and methods

We performed a population-based, case-control study in patients with a previous history of unprovoked VTE and subjected the participants to a standard fat tolerance test (1 g fat/kg body weight) in order to promote physiological coagulation activation.

Results

VTE patients had higher BMI (28.3 ± 4.4 kg/m² versus 26.3 ± 3.9 kg/m², p = 0.045) and greater waist circumference (98.2 ± 12.5 cm versus 93.4 ± 13.4 cm, p = 0.041) than age and sex matched controls. APC levels were equal in fasting plasma (3.00 ± 0.74 ng/ml and 2.99 ± 0.60 ng/ml, p = 0.66) but higher in postprandial plasma (3.18 ± 0.57 ng/ml and 2.81 ± 0.38 ng/ml, p = 0.008) collected from VTE patients and controls, respectively. Endogenous thrombin generation in plasma following a standardized meal, assessed by thrombin-antithrombin complex (TAT), increased similarly in both groups, whereas APC increased only among the VTE patients during the postprandial state. Plasma levels of APC increased linearly with TAT in the postprandial state (p for linear trend = 0.012).

Conclusions

Our findings fail to support the hypothesis that low APC levels are linked to increased thrombotic risk in unprovoked VTE, and they suggest that plasma APC is a biomarker of thrombin generation.