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Background and Study Aims/Object Despite the relevance of molecular criteria for brain tumor diagnosis and prognosis, meningioma grading is still solely based on histologic features. Atypical meningiomas (AMs; WHO grade II) display a great histologic heterogeneity and individual courses of disease can differ significantly. This study aimed to identify clinically aggressive AMs that are prone to early recurrence after gross total resection (GTR) by assessing a specific histologic score. Patients and Methods A retrospective analysis of 28 consecutive patients (17 females and 11 males; mean age of 62 years [range: 35–88 years]) treated in our institution between January 2006 and December 2015 was performed. Basic demographic and clinical characteristics were assessed. A scoring scale was designed to address the histologic diversity by summing up the individual histologic features in every tumor sample. According to that, points were awarded as follows: major AM defining criterion (3 points) and minor criterion (1 point). Results The subclassification based on our specific histologic score revealed no significant difference in frequency of one (46.4%) or two (42.9%) AM defining features; three criteria were less frequently seen (10.7%). Mean follow-up was 61.89 ± 9.03 months. Local recurrence occurred in 35.7% after a mean time of 37.4 ± 22.6 months after primary surgery. Age > 60 years was significantly associated with a shorter progression-free survival (PFS). There was a trend toward shorter PFS with increasing scores, tantamount with the presence of several AM defining histologic criteria in one sample. No tumor relapse was seen when diagnosis was based only on minor criteria. Conclusion AMs display a histologic diversity. There is a trend toward shorter PFS with increasing numbers of AM defining histologic features. The inclusion of this score in the decision algorithm regarding further treatment for patients >60 years after GTR might be helpful and should be evaluated in further studies.

Obesity is associated with an increase prevalence of neuropsychiatric symptoms and diseases, such as depression. Based on the facts that pro-inflammatory cytokines are able to modulate behavior, and that obesity is characterized by a chronic low-grade inflammatory state, inflammation has been hypothesized to contribute to the neuropsychiatric comorbidity in obese individuals. However, a causal link between inflammation and the development of neuropsychiatric symptoms is hard to establish in humans. Here, we used an inflammatory stimulus, i.e. the intravenous injection of lipopolysaccharide (LPS), in a double-blind placebo-controlled design, to determine the vulnerability of obese individuals to inflammation-induced behavioral changes. The hypothesis was that obese individuals would show heightened behavioral response compared to normal-weight subjects for the same inflammatory stimulus, reflecting an increased sensitivity to the behavioral effects of pro-inflammatory cytokines. LPS (dose 0.8 ng/kg body weight, adjusted for estimated blood volume in obese subjects) and placebo (saline) were intravenously injected in 14 obese healthy subjects and 23 normal-weight healthy subjects in a within-subject, randomized, crossover design. LPS administration induced, in both groups, an acute increase in blood concentrations of cytokines (interleukin-6, tumor necrosis factor-α, and IL-10), as well as in body temperature, cortisol, norepinephrine, sickness symptoms, fatigue, negative mood, and state anxiety. There were little differences in the immune and behavioral responses to LPS between obese and normal-weight subjects, but the cortisol response to LPS was strongly attenuated in obese individuals. Higher percentage of body fat was related to a lower cortisol response to LPS. Taken together, the population of young and healthy obese individuals in this study did not exhibit an increased behavioral sensitivity to cytokines, but an attenuated cortisol response to the immune challenge. Future studies will need to determine whether additional physiological and psychological factors interact with the state of obesity to increase the risk for inflammation-induced neuropsychiatric symptoms.

Reliable prediction of outcomes of aneurysmal subarachnoid hemorrhage (aSAH) based on factors available at patient admission may support responsible allocation of resources as well as treatment decisions. Radiographic and clinical scoring systems may help clinicians estimate disease severity, but their predictive value is limited, especially in devising treatment strategies. In this study, we aimed to examine whether a machine learning (ML) approach using variables available on admission may improve outcome prediction in aSAH compared to established scoring systems. Combined clinical and radiographic features as well as standard scores (Hunt & Hess, WFNS, BNI, Fisher, and VASOGRADE) available on patient admission were analyzed using a consecutive single-center database of patients that presented with aSAH (n = 388). Different ML models (seven algorithms including three types of traditional generalized linear models, as well as a tree bosting algorithm, a support vector machine classifier (SVMC), a Naive Bayes (NB) classifier, and a multilayer perceptron (MLP) artificial neural net) were trained for single features, scores, and combined features with a random split into training and test sets (4:1 ratio), ten-fold cross-validation, and 50 shuffles. For combined features, feature importance was calculated. There was no difference in performance between traditional and other ML applications using traditional clinico-radiographic features. Also, no relevant difference was identified between a combined set of clinico-radiological features available on admission (highest AUC 0.78, tree boosting) and the best performing clinical score GCS (highest AUC 0.76, tree boosting). GCS and age were the most important variables for the feature combination. In this cohort of patients with aSAH, the performance of functional outcome prediction by machine learning techniques was comparable to traditional methods and established clinical scores. Future work is necessary to examine input variables other than traditional clinico-radiographic features and to evaluate whether a higher performance for outcome prediction in aSAH can be achieved. Supplementary Information The online version contains supplementary material available at 10.1007/s10143-020-01453-6.

Data from clinical and cross-sectional studies suggest that inflammation contributes to psychomotor slowing and attentional deficits found in depressive disorder. However, experimental evidence is still lacking. The aim of this study was to clarify the effect of inflammation on psychomotor slowing using an experimental and acute model of inflammation, in which twenty-two healthy volunteers received an intravenous injection of lipopolysaccharide (LPS, dose: 0.8 ​ng/kg body weight) and of placebo, in a randomized order following a double-blind within-subject crossover design. A reaction time test and a go/no-go test were conducted 3 ​h after the LPS/placebo injection and interleukin (IL)-6 and tumor necrosis factor (TNF)-α concentrations were assessed. No effect of experimental inflammation on reaction times or errors for either test was found. However, inflammation was related to worse self-rated performance and lower effort put in the tasks. Exploratory analyses indicated that reaction time fluctuated more over time during acute inflammation. These data indicate that acute inflammation has only modest effects on psychomotor speed and attention in healthy subjects objectively, but alters the subjective evaluation of test performance. Increased variability in reaction time might be the first objective sign of altered psychomotor ability and would merit further investigation., Highlights • The effect of experimental inflammation on psychomotor slowing was assessed. • Acute inflammation does not affect psychomotor speed in two reaction time tasks. • Inflammation altered the subjective evaluation of test performance. • In exploratory analyses, the variability of reaction time over time was affected.

Purpose The learned immunosuppressive placebo response has been demonstrated in experimental animals, healthy humans, and patients, and is suggested as a therapy for improving immunopharmacologic treatment. It remains unclear, however, whether potential adverse events induced by the drug are also behaviorally conditioned. Employing an established taste–immune learning paradigm in healthy humans using the calcineurin inhibitor and immunosuppressive drug cyclosporine A (CsA) as an unconditioned stimulus, we investigated whether and to what extent perceived adverse events induced by acute CsA administration are behaviorally conditioned. Methods A total of 68 healthy male subjects were exposed to the established taste–immune learning paradigm, receiving either placebo or CsA (10 mg/kg) as an unconditioned stimulus, and a novel-tasting drink as a conditioned stimulus. Findings Subjects repeatedly receiving CsA during acquisition reported significantly more adverse events than did placebo-receiving subjects. However, during reexposure to the conditioned stimulus, the reported adverse events did not differ from those in the placebo control condition. Implications These data indicate that acute adverse events are not behaviorally conditioned during the learned immunosuppressive response. Our results further strengthen the great potential clinical relevance of employing the learned immunosuppressive placebo response as a therapy to support immunopharmacologic regimens, ultimately aiming to reduce the medical dosages required, thereby minimizing adverse drug events while maximizing the therapeutic benefit in patients. German Clinical Trial Register ( www.drks.de ) identifier: DRKS00007693 .

Background: Clinical data indicate that therapy with small-molecule immunosuppressive drugs is frequently accompanied by an incidence rate of neuropsychiatric symptoms. In the current approach, we investigated in rats whether repeated administration of rapamycin, reflecting clinical conditions of patients undergoing therapy with this mammalian target of rapamycin inhibitor, precipitates changes in neurobehavioral functioning. Methods: Male adult Dark Agouti rats were daily treated with i.p. injections of rapamycin (1, 3 mg/kg) or vehicle for 8 days. On days 6 and 7, respectively, behavioral performance in the Elevated Plus-Maze and the Open-Field Test was evaluated. One day later, amygdala tissue and blood samples were taken to analyze protein expression ex vivo. Results: The results show that animals treated with rapamycin displayed alterations in Elevated Plus-Maze performance with more pronounced effects in the higher dose group. Besides, an increase in glucocorticoid receptor density in the amygdala was seen in both treatment groups even though p-p70 ribosomal S6 kinase alpha, a marker for mammalian target of rapamycin functioning, was not affected. Protein level of the neuronal activity marker c-Fos was again only elevated in the higher dose group. Importantly, effects occurred in the absence of acute peripheral neuroendocrine changes. Conclusions: Our findings indicate that anxiety-related behavior following rapamycin treatment was not directly attributed to mTOR-dependent mechanisms or stress but rather due to hyperexcitability of the amygdala together with glucocorticoid receptor-regulated mechanism(s) in this brain region. Together, the present results support the contention that subchronic treatment with rapamycin may induce neurobehavioral alterations in healthy, naive subjects. We here provide novel insights in central effects of systemic rapamycin in otherwise healthy subjects but also raise the question whether therapy with this drug may have detrimental effects on patients’ neuropsychological functioning during immune therapy. CA Hadamitzky

Pediatric posterior fossa ependymoma (PF) is one of the most common brain tumors in children. Recently, two subtypes of PF were identified. PF-A has a dismal prognosis and shows a hypermethylation phenotype, whereas PF-B shows a great genomic instability. The ten-eleven translocation methylcytosine dioxygenase 2 (TET2) gene (TET2) has been linked to the regulation of DNA methylation. We analyzed TET2 promotor methylation and protein expression to assess the role of TET2 in PF. Medical records of all PF cases treated in our institution between 1993 and 2015 were evaluated regarding tumor histology, grade, tumor location, gender, age, tumor recurrence, distant metastasis, survival and time to progression. Subsequently, we analyzed TET2 promotor methylation using methylation-specific polymerase chain reaction. TET2 protein expression was assessed using immunohistochemistry. Low TET2 expression was detected in seven of 17 cases. There was an association between low TET2 expression and tumor recurrence (P = 0.049). A TET2 promotor methylation was detected in five of 10 cases. There was no association between the TET2 promotor methylation with recurrence, tumor grade or gender. TET2 promotor methylation and low TET2 expression was detected in a subgroup of PF. Our data show an association between low TET2 expression and tumor recurrence in PF.

Psychiatric symptoms as seen in affective and anxiety disorders frequently appear during glioblastoma (GBM) treatment and disease progression, additionally deteriorate patient's daily life routine. These central comorbidities are difficult to recognize and the causes for these effects are unknown. Since overactivation of mechanistic target of rapamycin (mTOR)- signaling is one key driver in GBM growth, the present study aimed at examining in rats with experimentally induced GBM, neurobehavioral consequences during disease progression and therapy. Male Fisher 344 rats were implanted with syngeneic RG2 tumor cells in the right striatum and treated with the mTOR inhibitor rapamycin (3 mg/kg; once daily, for eight days) before behavioral performance, brain protein expression, and blood samples were analyzed. We could show that treatment with rapamycin diminished GBM tumor growth, confirming mTOR-signaling as one key driver for tumor growth. Importantly, in GBM animals' anxiety-like behavior was observed but only after treatment with rapamycin. These behavioral alterations were moreover accompanied by aberrant glucocorticoid receptor, phosphorylated p70 ribosomal S6 kinase alpha (p-p70s6k), and brain derived neurotrophic factor protein expression in the hippocampus and amygdala in the non-tumor-infiltrated hemisphere of the brain. Despite the beneficial effects on GBM tumor growth, our findings indicate that therapy with rapamycin impaired neurobehavioral functioning. This experimental approach has a high translational value. For one, it emphasizes aberrant mTOR functioning as a central feature mechanistically linking complex brain diseases and behavioral disturbances. For another, it highlights the importance of elaborating the cause of unwanted central effects of immunosuppressive and antiproliferative drugs used in transplantation medicine, immunotherapy, and oncology.

Suppression of immune functions can be elicited by behavioral conditioning using drugs such as cyclosporine A, cyclophosphamide, or opioids. Nevertheless, little is known regarding the conditioned actions of clinically approved immunosuppressive drugs with distinct cell signaling pathways. The present study tested the assumption to condition immunopharmacological properties of rapamycin (sirolimus), a small-molecule drug widely used as anti-tumor medication and to prevent graft rejection. For this purpose, a conditioned taste avoidance (CTA) paradigm was used, pairing the presentation of a novel taste (saccharin) as conditioned stimulus (CS) with injections of rapamycin as unconditioned stimulus (US). Subsequent re-exposure to the CS at a later time revealed that conditioning with rapamycin induced an only moderate CTA. However, pronounced conditioned immunopharmacological effects were observed, reflected by significantly reduced levels of IL-10 cytokine production and diminished proliferation of splenic CD4+ and CD8+ T cells in Dark Agouti and Fischer 344 rats. For one, these findings support earlier observations revealing that not a pronounced CTA but rather re-exposure to the CS or taste itself is essential for conditioned immunosuppression. Moreover, our results provide first evidence that the phenomenon of learned immune responses generalizes across many, if not all, small-molecule drugs with immunosuppressive properties, thereby providing the basis for employing learned immunopharmacological strategies in clinical contexts such as supportive therapy.

In a rat model of conditioned immunosuppression a novel taste (saccharin) as conditioned stimulus (CS) is paired with an injection of the immunosuppressive drug cyclosporine A (CsA) as unconditioned stimulus (US). Representation of the CS alone at a later time induces conditioned taste avoidance (CTA) towards the saccharin and concomitantly a marked suppression of IL-2 cytokine production in splenocytes. However, it is not known whether learned immune responses also work with other small-molecule immunosuppressive drugs. Therefore, we investigated the capability to behavioral condition anti-proliferative and anti-metabolic effects of rapamycin (RAPA), an inhibitor of the mTOR-signaling pathway, and methotrexate (MTX), an inhibitor of dihydrofolate reductase. Behavioral conditioning with RAPA CTA, a suppression of IL-10 cytokine production and CD4+ T-cell proliferation. Preliminary data of behavioral conditioning with MTX indicate CTA after five acquisition trials employing a high dose of this drug. These results provide first evidence that behavioral conditioning of immunomodulatory effects apply to different immuno-pharmacological drugs, crossing the blood brain barrier and targeting different cell signaling pathways.

Neuropsychiatric comorbidities, such as depression or anxiety, are frequently seen in glioblastoma (GBM)-patients restricting their quality of life. mTOR signaling has been implicated in the development of certain neurological disorders and is also a key driver for GBM tumor progression. Against this background, the present study analyzed effects of treatment with the mTOR inhibitor rapamycin on tumor growth, behavior, and brain protein expression in a rat model of GBM. Male Fisher 344 rats received intracranial implantation of RG2 rat-GBM cells. One week following surgery animals were treated with rapamycin (3 mg/kg) for 7 days. Subsequently, mood and anxiety-related behaviors were assessed and brain and blood samples were taken for biochemical analyses. Systemic treatment with rapamycin inhibited RG2-cell proliferation in vitro and tumor growth in vivo. Compared to SHAM operated controls GBM-rats displayed less coping strategies when exposed to the forced-swim test. This result, however, was not observed in GBM-rats treated with rapamycin. Importantly, this ”preventing” effect of rapamycin on stress-coping was accompanied by anxiety-related behavior assessed in the elevated plus-maze test. Correspondingly, in rapamycin treated GBM animals’ protein expression of glucocorticoid receptors was decreased in the hippocampus but increased in the amygdala. These findings for the first time show that, as seen in humans, that GBM disease progression in an experimental preclinical setting is associated with neurobehavioral alterations, partially mediated by central mTOR-dependent mechanisms.

The importance of placebo responses for the treatment of various medical conditions has increasingly been recognized, whereas knowledge and systematic application in clinical settings are still sparse. One possible application for placebo responses in pharmacotherapy is given by learning paradigms, such as behaviorally conditioned immunosuppression, aiming at drug dose reduction while maintaining therapeutic efficacy of drug treatment. In an established learning paradigm of conditioned taste aversion/avoidance (CTA) in both, rats and humans, respectively, a novel-tasting drinking solution (conditioned stimulus, CS) is paired with an injection of the immunosuppressive drug cyclosporine A (CsA) as unconditioned stimulus (US). The conditioned response, evoked by re-presenting the CS alone at a later time, is reflected by avoidance behavior of consuming the solution (conditioned taste aversion; CTA) and a diminished interleukin (IL)-2 and interferon (IFN)-γ cytokine production as well as mRNA expression of rat splenic T cells or human peripheral T lymphocytes, closely mimicking the immunosuppressive effects of CsA. However, due to unreinforced CS-re-exposure conditioned responses progressively decreases over time (extinction), reflecting a considerable challenge for potential clinical applications of this learned immunosuppression. The present article discusses and critically reviews actual approaches, applications but also limitations of learning paradigms in immune pharmacotherapy.