Ziprasidone--not haloperidol--induces more de-novo neurogenesis of adult neural stem cells derived from murine hippocampus

Adult Neural Stem Cells as Promising Targets in Psychiatric Disorders

The development of new therapies for psychiatric disorders is of utmost importance, given the enormous toll these disorders pose to society nowadays. This should be based on the identification of neural substrates and mechanisms that underlie disease etiopathophysiology. Adult neural stem cells (NSCs) have been emerging as a promising platform to counteract brain damage. In this perspective article, we put forth a detailed view of how NSCs operate in the adult brain and influence brain homeostasis, having profound implications at both behavioral and functional levels. We appraise evidence suggesting that adult NSCs play important roles in regulating several forms of brain plasticity, particularly emotional and cognitive flexibility, and that NSC dynamics are altered upon brain pathology. Furthermore, we discuss the potential therapeutic value of utilizing adult endogenous NSCs as vessels for regeneration, highlighting their importance as targets for the treatment of multiple mental illnesses, such as affective disorders, schizophrenia, and addiction. Finally, we speculate on strategies to surpass current challenges in neuropsychiatric disease modeling and brain repair.

Type 17 Immune Response Facilitates Progression of Inflammation and Correlates with Cognition in Stable Schizophrenia

Dysregulation of the type 17 immune pathway has already been considered in schizophrenia and we previously measured decreased sera values of interleukin (IL)-17 in early stages. We further explored the possible correlation of IL-17 systemic levels with proinflammatory cytokines and cognitive scores and additionally analyzed the percentage of IL-17 producing lymphocytes in peripheral blood of patients with stable schizophrenia. We included 27 patients diagnosed with schizophrenia (F20), after a three-month stable depot antipsychotic therapy (risperidone or paliperidone) and 18 healthy control subjects. Positive and Negative Syndrome Scale of Schizophrenia and the Montreal-Cognitive Assessment (MoCA) were conducted. Sera concentrations of IL-17, IL-6, tumor necrosis factor alpha (TNF-α) and soluble ST2 receptor (sST2) were measured. Flow cytometry and Natural Killer (NK) and T cell analyses were done in 10 patients and 10 healthy controls. Moderate positive correlation was established between IL-17 and TNF-α (r = 0.640; p = 0.001), IL-17 and IL-6 (r = 0.514; p = 0.006), IL-17 and sST2 (r = 0.394; p = 0.042). Furthermore, a positive correlation between the serum levels of IL-17 and MoCA scores was observed, especially with visuospatial and executive functioning, as well as language functioning and delayed recall (p < 0.05). Significantly higher percentage of IL-17 producing CD56⁺ NK cells was measured in peripheral blood of patients with schizophrenia in remission vs. healthy individuals (p = 0.001). The percentage of CD4⁺ T cells and CD4⁺ T cells that produce IL-17 was significantly increased in patients (p = 0.001). This study revealed the involvement of innate type 17 immune response in the progression of inflammation and this could be related to cognitive functioning in stable schizophrenia.

Interleukine-17 Administration Modulates Adult Hippocampal Neurogenesis and Improves Spatial Learning in Mice

Adult hippocampal neurogenesis plays an important role in health and disease. Regulating neurogenesis may be a key mechanism in the pathophysiology and treatment of several neurobehavioral disorders such as schizophrenia, depression, autism spectrum disorders and Alzheimer's disease. Cytokines are known to affect adult neurogenesis, but conflicting studies have been reported with regard to their actual role. Interleukine-17 (IL-17), a potent pro-inflammatory cytokine, has been shown to inhibit proliferation of neuroprogenitors and thus reduce hippocampal neurogenesis, while other studies suggested it can promote neurite outgrowth. In the present study we sought to explore the possible effect of a single dose administration of IL-17 on neurogenesis related behavior, i.e. spatial learning. Surprisingly, ICR mice injected with IL-17 (8 μg) had a significant slight improvement in spatial learning in the Morris water maze paradigm, without any changes in general locomotion compared with control mice. Indeed, the expression of neurogenesis related genes was down regulated following IL-17 treatment. However, we detected an upregulation in the expression of FGF-13, a gene promoting microtubule polymerization and neurite outgrowth, thus supporting neuronal maturation. We thus suggest that IL-17 has a complex role in regulating adult neurogenesis: inhibiting neuroprogenitors proliferation on one hand, while promoting maturation of already formed neuroblasts on the other hand. Our findings suggest that these roles can potentially affect neurogenesis related behavior. Its actual role in health and disease is yet to be determined.

Therapy of Schizoaffective Disorder and Paranoid Schizophrenia with Episodic Course

Background. The use of atypical antipsychotics in schizophrenia contributes to the reduction of psychotic, affective, negative and cognitive disorders.

Aims. To evaluate the effectiveness of ziprasidone therapy in patients with schizoaffective disorder and paranoid schizophrenia with episodic course.

Materials and methods. In accordance with ICD-10 there were 14 (63.6 %) people with schizoaffective disorder (F25), 8 (36.4 %) people with paranoid schizophrenia, episodic course (F20.x1). Treatment with ziprasidone lasted 42 days. The dose of ziprasidone in 6 patients (27.3 %) was 80 mg, in 10 patients (45.5 %) – 120 mg, in 6 patients (27.3 %) – 160 mg. Evaluation of the effectiveness of ziprasidone therapy was carried out using psychometric scales (PANSS, General clinical impression scale to assess the effectiveness of therapy – CGI-S, CGI-I), adverse events were registered with the UKU scale.

Results. The number of respondents was 19 (86.3 %) (reduction of the total score on the PANSS scale > 20 % of the pre-treatment level). Ziprasidone was effective in patients with schizoaffective disorder with a significant decrease in total score on PANSS subscales to the 14 th day of therapy (p < 0.05), with paranoid schizophrenia with episodic course – by the 21st day (p < 0.01). According to the CGI-S scale at the end of therapy, “borderline condition” was observed in 10 patients (52.6 %), mild severity – in 3 (15.8 %), normal condition – in 6 (31.6 %). CGI-I scale showed a significant improvement in 10 patients (52.6 %), marked improvement – in 9 patients (47.4 %). Among the mild adverse events that do not require discontinuation of the drug, we noted: weakness – in 3 patients (15.8 %), drowsiness – in 3 (15.8 %), impaired concentration – in 2 (10.5 %), orthostatic dizziness – in 2 (10.5 %), galactorrhea – in 1 (5.3 %).

Conclusions. Ziprasidone is an effective antipsychotic drug that has a safe tolerability profile. It can be used in patients with schizoaffective disorders and paranoid schizophrenia with episodic course.

Recommendation on test readiness criteria for new approach methods in toxicology: Exemplified for developmental neurotoxicity

Multiple non-animal-based test methods have never been formally validated. In order to use such new approach methods (NAMs) in a regulatory context, criteria to define their readiness are necessary. The field of developmental neurotoxicity (DNT) testing is used to exemplify the application of readiness criteria. The costs and number of untested chemicals are overwhelming for in vivo DNT testing. Thus, there is a need for inexpensive, high-throughput NAMs, to obtain initial information on potential hazards, and to allow prioritization for further testing. A background on the regulatory and scientific status of DNT testing is provided showing different types of test readiness levels, depending on the intended use of data from NAMs. Readiness criteria, compiled during a stakeholder workshop, uniting scientists from academia, industry and regulatory authorities are presented. An important step beyond the listing of criteria, was the suggestion for a preliminary scoring scheme. On this basis a (semi)-quantitative analysis process was assembled on test readiness of 17 NAMs with respect to various uses (e.g. prioritization/screening, risk assessment). The scoring results suggest that several assays are currently at high readiness levels. Therefore, suggestions are made on how DNT NAMs may be assembled into an integrated approach to testing and assessment (IATA). In parallel, the testing state in these assays was compiled for more than 1000 compounds. Finally, a vision is presented on how further NAM development may be guided by knowledge of signaling pathways necessary for brain development, DNT pathophysiology, and relevant adverse outcome pathways (AOP).

The Role of Neural Plasticity in Depression: From Hippocampus to Prefrontal Cortex

Neural plasticity, a fundamental mechanism of neuronal adaptation, is disrupted in depression. The changes in neural plasticity induced by stress and other negative stimuli play a significant role in the onset and development of depression. Antidepressant treatments have also been found to exert their antidepressant effects through regulatory effects on neural plasticity. However, the detailed mechanisms of neural plasticity in depression still remain unclear. Therefore, in this review, we summarize the recent literature to elaborate the possible mechanistic role of neural plasticity in depression. Taken together, these findings may pave the way for future progress in neural plasticity studies.

The current state of the neurogenic theory of depression and anxiety

Newborn neurons are continuously added to the adult hippocampus. Early studies found that adult neurogenesis is impaired in models of depression and anxiety and accelerated by antidepressant treatment. This led to the theory that depression results from impaired adult neurogenesis and restoration of adult neurogenesis leads to recovery. Follow up studies yielded a complex body of often inconsistent results, and the veracity of this theory is uncertain. We propose five criteria for acceptance of this theory, we review the recent evidence for each criterion, and we draw the following conclusions: Diverse animal models of depression and anxiety have impaired neurogenesis. Neurogenesis is consistently boosted by antidepressants in animal models only when animals are stressed. Ablation of neurogenesis in animal models impairs cognitive functions relevant to depression, but only a minority of studies find that ablation causes depression or anxiety. Recent human neuroimaging and postmortem studies are consistent with the neurogenic theory, but they are indirect. Finally, a novel drug developed based on the neurogenic theory is promising in animal models.

Hypothalamic subependymal niche: a novel site of the adult neurogenesis

The discovery of undifferentiated, actively proliferating neural stem cells (NSCs) in the mature brain opened a brand new chapter in the contemporary neuroscience. Adult neurogenesis appears to occur in specific brain regions (including hypothalamus) throughout vertebrates’ life, being considered an important player in the processes of memory, learning, and neural plasticity. In the adult mammalian brain, NSCs are located mainly in the subgranular zone (SGZ) of the hippocampal dentate gyrus and in the subventricular zone (SVZ) of the lateral ventricle ependymal wall. Besides these classical regions, hypothalamic neurogenesis occurring mainly along and beneath the third ventricle wall seems to be especially well documented. Neurogenic zones in SGZ, SVZ, and in the hypothalamus share some particular common features like similar cellular cytoarchitecture, vascularization pattern, and extracellular matrix properties. Hypothalamic neurogenic niche is formed mainly by four special types of radial glia-like tanycytes. They are characterized by distinct expression of some neural progenitor and stem cell markers. Moreover, there are numerous suggestions that newborn hypothalamic neurons have a significant ability to integrate into the local neural pathways and to play important physiological roles, especially in the energy balance regulation. Newly formed neurons in the hypothalamus can synthesize and release food intake regulating neuropeptides and they are sensitive to the leptin. On the other hand, high-fat diet positively influences hypothalamic neurogenesis in rodents. The nature of this intriguing new site of adult neurogenesis is still so far poorly studied and requires further investigations.