Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the central nervous system (CNS), prostaglandin (PG) and other bioactive lipids regulate vital aspects of neural membrane biology, including protein-lipid interactions, trans-membrane and trans-synaptic signaling. However, a series of highly reactive PGs, free fatty acids, lysophospolipids, eicosanoids, platelet-activating factor, and reactive oxygen species (ROS), all generated by enhanced phospholipase A2 (PLA2) activity and arachidonic acid (AA) release, participate in cellular injury, particularly in neurodegeneration. PLA2 activation and PG production are among the earliest initiating events in triggering brain-damage pathways, which can lead to long-term neurologic deficits. Altered membrane-associated PLA2 activities have been correlated with several forms of acute and chronic brain injury, including cerebral trauma, ischemic damage, induced seizures in the brain and epilepsy, schizophrenia, and in particular, Alzheimer's disease (AD). Biochemical mechanisms of PLA2 overactivation and its pathophysiological consequences on CNS structure and function have been extensively studied using animal models and brain cells in culture triggered with PLA2 inducers, PGs, cytokines, and related lipid mediators. Moreover, the expression of both COX-2 and PLA2 appears to be strongly activated during Alzheimer's disease (AD), indicating the importance of inflammatory gene pathways as a response to brain injury. This review addresses some current ideas concerning how brain PLA2 and brain PGs are early and key players in acute neural trauma and in brain-cell damage associated with chronic neurodegenerative diseases such as AD.
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PMID:Prostaglandins and other lipid mediators in Alzheimer's disease. 1243 19

Recent advances in immunological research regarding the differentiation between the type-1 and type-2 immune response are discussed. Increased levels of Interleukin-6 (IL-6) and the activation of the IL-6 system in schizophrenia might be the result of the activation of type-2 monocytes/macrophages, too. On the contrary, several parameters of the specific cellular immune system are blunted, e. g. the decreased type-1 related immune parameters in schizophrenic patients. This study was performed as a double-blind, placebo-controlled, randomized evaluation of risperidone and celecoxib versus risperidone and placebo. Fifty schizophrenic patients were included in the study: 25 patients received risperidone and placebo, and 25 patients received risperidone and celecoxib for 5 weeks after the wash-out period. The treatment effect was calculated by ANCOVA. In parallel, serum levels of sTNF-R1 and sIL- 2R, and the percentages of CD3(+)-, CD4(+)-, and CD19(+) lymphocytes were estimated. As expected, both groups of schizophrenic patients showed significant improvement. However, the celecoxib add-on therapy group showed a significant group effect in the PANSS total score. The cytokines and lymphocytes reflected the type-1/type-2 balancing effects of COX-2 inhibitors. Additional treatment with celecoxib has significant positive effects on the therapeutic action of risperidone with regard to the total schizophrenia psychopathology. Moreover, the fact that treatment with an immunomodulatory drug shows beneficial effects on the symptomatology of schizophrenia indicates that immune dysfunction in schizophrenia is not just an epiphenomenon, but related to the pathomechanism of the disorder.
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PMID:COX-2 inhibition as a treatment approach in schizophrenia: immunological considerations and clinical effects of celecoxib add-on therapy. 1499 74

Kynurenic acid (KYNA), an endogenous glutamate-receptor antagonist preferentially blocking NMDA-receptors, has analgesic properties and has also been implicated in the pathophysiology of schizophrenia. Recently, the non-steroid anti-inflammatory drug (NSAID) diclofenac was found to increase rat brain KYNA. Here, we analyze whether cyclooxygenase (COX)-1 or COX-2 modulate the levels of rat brain KYNA. The non-selective COX-inhibitor diclofenac (50 mg/kg, i.p.) or indomethacin (50 mg/kg, i.p.), a non-selective inhibitor with a preferential selectivity for COX-1, produced an elevation in brain KYNA. In contrast, the COX-2 selective inhibitors parecoxib (25 mg/kg, i.p.) or meloxicam (5 mg/kg, i.p.) decreased brain KYNA. Both elevation and lowering of brain KYNA by indomethacin or parecoxib, respectively, were prevented by the prostaglandin E1/E2 agonist misoprostol (1 mg/kg, s.c.). It is proposed that increased brain KYNA formation induced by NSAIDs displaying an inhibitory action on COX-1 contribute to their analgesic efficacy as well as to their psychiatric side effects.
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PMID:Prostaglandin-mediated control of rat brain kynurenic acid synthesis--opposite actions by COX-1 and COX-2 isoforms. 1551 27

Celecoxib augmentation therapy has been reported to enhance the rate of clinical response for patients with schizophrenia. This may be due in part to an effect of celecoxib in the immune dysfunction associated with schizophrenia. Given concerns about the safety of COX-2 inhibitors, studies investigating cytokine levels in medicated patients with schizophrenia are of public health importance. Twenty-eight schizophrenia subjects stabilized on olanzapine or risperidone were randomized to receive 8 wk of celecoxib (400 mg/d) or placebo. Serum soluble IL-2 receptor (sIL-2r) and in-vitro PHA-stimulated whole-blood cytokine production levels were measured at baseline, 1 wk, and 8 wk. Celecoxib augmentation did not alter any of the cytokine parameters measured for the overall study group. However, 1 wk of celecoxib augmentation increased TNF-alpha and IL-2 production levels in olanzapine-treated subjects. These elevations did not persist by week 8. Overall, celecoxib does not significantly modify cytokine levels in medicated schizophrenia subjects.
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PMID:The effects of celecoxib augmentation on cytokine levels in schizophrenia. 1603 56

A better understanding of the human immune system and its complex interactions has resulted in new insights into the pathoaetiological mechanisms of psychiatric disorders. As a result, new treatment options are being explored. Several findings suggest that an imbalanced immune response is involved in the pathophysiology of schizophrenia. COX-2 inhibitors are known to influence the immune system in a way that may redirect this imbalance. Based on these suggestions, the COX-2 inhibitor celecoxib has been tested as a possible adjunctive therapeutic approach in the treatment of schizophrenia. While the first trial using celecoxib as add-on therapy to an atypical antipsychotic showed a significant beneficial effect, recent studies demonstrated that this effect may be limited to patients with recent-onset schizophrenia.
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PMID:COX-2 inhibitors as adjunctive therapy in schizophrenia: rationale for use and evidence to date. 1618 91

The number of adults in the US affected by bipolar disorder, depression, or schizophrenia is approaching 15 million. Despite decades of research, etiologies of these illnesses remain elusive. Theories of aberrant brain morphology, neurotransmission, and signal conduction have provided the heuristic framework for a large body of literature, with attention focused upon hypotheses of monoamine signaling underlying psychiatric disease. More recently, attention has turned to potential contributions of other signaling pathways, including the arachidonic acid cascade and generation of prostaglandins (PG). To determine the potential involvement of the pathways leading to PGE2 synthesis in psychiatric disease, immunohistochemistry and immunoblotting were performed to measure regional expression of the cyclooxygenases (COX) and one of the terminal PGE2 synthases (PGES) in postmortem tissue provided by The Stanley Medical Research Institute. For normal, bipolar, depressed, and schizophrenic subjects, COX-1 and COX-2 protein levels did not differ across region and patient populations. In contrast, there was a significant effect of diagnosis on cytosolic PGES (cPGES) protein levels in the frontal cortex, with remarkable decreases observed in all psychiatric groups relative to normal tissue (P < 0.05). Significant reduction of cPGES expression was also found in the temporal cortex of bipolar subjects. Evaluation of medicated vs. non-medicated subjects revealed a significant effect of medication on cPGES expression in the frontal cortex of bipolar, but not depressed or schizophrenic subjects. These novel findings further support hypotheses of abnormalities in fatty acid and phospholipid metabolism in regions associated with psychiatric disease.
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PMID:Cytosolic prostaglandin E2 synthase (cPGES) expression is decreased in discrete cortical regions in psychiatric disease. 1680 20

Clozapine has a remarkable efficacy in treatment-resistant schizophrenia and is one of the most effective antipsychotic drugs used today. The clinical effects of clozapine are suggested to be related to a unique interaction with a variety of receptor systems, including the glutamatergic receptors. Kynurenic acid (KYNA) is an endogenous blocker of alpha7 nicotinic receptors and a glutamate-receptor antagonist, preferentially blocking N-methyl-D-aspartate (NMDA) receptors. In the present in vivo electrophysiological study, changes in endogenous concentration of brain KYNA were utilized to analyze an interaction between clozapine and the glycine site of NMDA receptors. In control rats intravenously administered clozapine (0.078-10 mg/kg) increased the firing rate and the burst firing activity of dopamine (DA) neurons in the ventral tegmental area (VTA). Pretreatment with indomethacin (50 mg/kg, i.p., 1-3.5 h), a cyclooxygenase (COX)-inhibitor with a preferential selectivity for COX-1, which produced a significant elevation in brain KYNA levels, reversed the excitatory action of clozapine into an inhibitory response. In contrast, pretreatment with the COX-2 selective inhibitor parecoxib (25 mg/kg, i.v., 1-1.5 h) decreased brain KYNA formation and furthermore, clearly potentiated the excitatory effect of clozapine. Our results show that endogenous levels of brain KYNA are of importance for the response of clozapine on VTA DA neurons. On the basis of the present data we propose that clozapine is able to interact with glutamatergic mechanisms, via actions at the NMDA/glycine receptor.
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PMID:Clozapine interacts with the glycine site of the NMDA receptor: electrophysiological studies of dopamine neurons in the rat ventral tegmental area. 1859 Jul 45

Antidepressant and antipsychotic drugs, predominantly serotonin and/or norepinephrine reuptake inhibitors and dopamine D2-antagonizing antipsychotic compounds, have several limitations. In addition, the exact pathophysiological mechanism leading to serotonergic, noradrenergic and dopaminergic dysfunction in psychotic disorders remains unclear. It has been postulated that an inflammatory mechanism may be involved in the pathogenesis of both depression and psychotic disorders. Furthermore, the differential activation of the enzyme indoleamine 2,3-dioxygenase (IDO) and of the tryptophan/kynurenine metabolic pathway, resulting in the increased production of kynurenic acid in schizophrenia, and a possible increase in quinolinic acid in depression, also may play a key role in these diseases. Such differences are associated with an imbalance in glutamatergic neurotransmission that may contribute to increased levels of NMDA agonism in depression and NMDA antagonism in schizophrenia. In addition, immunological imbalance results in the increased production of PGE2 in schizophrenia and depression, as well as increased COX-2 expression in schizophrenia. Although there is evidence supporting the hypothesis that interactions between immune system components, IDO, the serotonergic system and glutamatergic neurotransmission play a key role in schizophrenia and depression, several gaps in knowledge remain, such as regarding the role of genetics, disease course, gender and different psychopathological states. There is evidence indicating that anti-inflammatory therapy may have beneficial effects in schizophrenia and major depression (MD). COX-2 inhibitors have been tested in animal models and in preliminary clinical trials, demonstrating favorable activity compared with placebo, both in schizophrenia and MD. However, the effects of COX-2 inhibition in the CNS, as well as toward different components of the inflammatory system, kynurenine metabolism and glutamatergic neurotransmission, require further evaluation, which should include clinical trials with larger numbers of patients. The potential inflammatory mechanism in schizophrenia and MD, and the possible therapeutic advantages of targeting this mechanism in the treatment of these disorders is discussed in this review.
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PMID:COX-2 inhibitors as antidepressants and antipsychotics: clinical evidence. 2004 57

The non-steroidal anti-inflammatory drugs (NSAIDs) are diverse group of compounds used for the treatment of inflammation, since the introduction of acetylsalicylic acid in 1899. Traditional (first generation) NSAIDs exert antiinflammatory, analgesic, and antipyretic effects through the blockade of prostaglandin synthesis via non-selective inhibition of cyclooxygenase (COX-1 and COX-2) isozymes. Their use is associated with side effects such as gastrointestinal and renal toxicity. A number of selective (second generation) COX-2 inhibitors (rofecoxib, celecoxib, valdecoxib etc.) were developed as safer NSAIDs with improved gastric safety profile. Observation of increased cardiovascular risks in APPROVe (Adenomatous Polyp Prevention on Vioxx) study sent tremors and led to voluntary withdrawn of Vioxx (rofecoxib) by Merck from the market in September 2004 followed by Bextra (valdecoxib) in 2005 raising a question on the safety of selective COX-2 inhibitors. This leads to the belief that these effects are mechanism based and may be class effect. However, some studies suggested association of traditional NSAIDs with similar effects requiring a relook into the whole class of NSAIDs rather than simply victimizing the selective COX-2 inhibitors. Recognition of new avenues for selective COX-2 inhibitors such as cancer, Alzheimer's disease, Parkinson's disease, schizophrenia, major depression, ischemic brain injury and diabetic peripheral nephropathy has kindled the interest in these compounds. This review highlights the various structural classes of selective COX-2 inhibitors developed during past seven years (2003-2009) with special emphasis on diaryl-hetero/carbo-cyclic class of compounds. Molecular modeling aspects are also briefly discussed.
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PMID:Progress in COX-2 inhibitors: a journey so far. 2016 30

Reporting bias represents a major problem in the assessment of health care interventions. Several prominent cases have been described in the literature, for example, in the reporting of trials of antidepressants, Class I anti-arrhythmic drugs, and selective COX-2 inhibitors. The aim of this narrative review is to gain an overview of reporting bias in the medical literature, focussing on publication bias and selective outcome reporting. We explore whether these types of bias have been shown in areas beyond the well-known cases noted above, in order to gain an impression of how widespread the problem is. For this purpose, we screened relevant articles on reporting bias that had previously been obtained by the German Institute for Quality and Efficiency in Health Care in the context of its health technology assessment reports and other research work, together with the reference lists of these articles.We identified reporting bias in 40 indications comprising around 50 different pharmacological, surgical (e.g. vacuum-assisted closure therapy), diagnostic (e.g. ultrasound), and preventive (e.g. cancer vaccines) interventions. Regarding pharmacological interventions, cases of reporting bias were, for example, identified in the treatment of the following conditions: depression, bipolar disorder, schizophrenia, anxiety disorder, attention-deficit hyperactivity disorder, Alzheimer's disease, pain, migraine, cardiovascular disease, gastric ulcers, irritable bowel syndrome, urinary incontinence, atopic dermatitis, diabetes mellitus type 2, hypercholesterolaemia, thyroid disorders, menopausal symptoms, various types of cancer (e.g. ovarian cancer and melanoma), various types of infections (e.g. HIV, influenza and Hepatitis B), and acute trauma. Many cases involved the withholding of study data by manufacturers and regulatory agencies or the active attempt by manufacturers to suppress publication. The ascertained effects of reporting bias included the overestimation of efficacy and the underestimation of safety risks of interventions.In conclusion, reporting bias is a widespread phenomenon in the medical literature. Mandatory prospective registration of trials and public access to study data via results databases need to be introduced on a worldwide scale. This will allow for an independent review of research data, help fulfil ethical obligations towards patients, and ensure a basis for fully-informed decision making in the health care system.
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PMID:Reporting bias in medical research - a narrative review. 2038 11


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