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Tallarico M, Pisano M, Leo A, Russo E, Citraro R, De Sarro G. Antidepressant Drugs for Seizures and Epilepsy: Where do we Stand? Curr Neuropharmacol 2023; 21:1691-1713. [PMID: 35761500 PMCID: PMC10514547 DOI: 10.2174/1570159x20666220627160048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 06/13/2022] [Accepted: 06/18/2022] [Indexed: 11/22/2022] Open
Abstract
People with epilepsy (PWE) are more likely to develop depression and both these complex chronic diseases greatly affect health-related quality of life (QOL). This comorbidity contributes to the deterioration of the QOL further than increasing the severity of epilepsy worsening prognosis. Strong scientific evidence suggests the presence of shared pathogenic mechanisms. The correct identification and management of these factors are crucial in order to improve patients' QOL. This review article discusses recent original research on the most common pathogenic mechanisms of depression in PWE and highlights the effects of antidepressant drugs (ADs) against seizures in PWE and animal models of seizures and epilepsy. Newer ADs, such as selective serotonin reuptake inhibitors (SRRI) or serotonin-noradrenaline reuptake inhibitors (SNRI), particularly sertraline, citalopram, mirtazapine, reboxetine, paroxetine, fluoxetine, escitalopram, fluvoxamine, venlafaxine, duloxetine may lead to improvements in epilepsy severity whereas the use of older tricyclic antidepressant (TCAs) can increase the occurrence of seizures. Most of the data demonstrate the acute effects of ADs in animal models of epilepsy while there is a limited number of studies about the chronic antidepressant effects in epilepsy and epileptogenesis or on clinical efficacy. Much longer treatments are needed in order to validate the effectiveness of these new alternatives in the treatment and the development of epilepsy, while further clinical studies with appropriate protocols are warranted in order to understand the real potential contribution of these drugs in the management of PWE (besides their effects on mood).
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Affiliation(s)
- Martina Tallarico
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Maria Pisano
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Antonio Leo
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Emilio Russo
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Rita Citraro
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Giovambattista De Sarro
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
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Singh T, Mishra A, Goel RK. PTZ kindling model for epileptogenesis, refractory epilepsy, and associated comorbidities: relevance and reliability. Metab Brain Dis 2021; 36:1573-1590. [PMID: 34427842 DOI: 10.1007/s11011-021-00823-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 08/14/2021] [Indexed: 12/13/2022]
Abstract
Pentylenetetrazole (PTZ)-induced seizure is one of the gold standard mouse models for rapid evaluation of novel anticonvulsants. Synchronically, PTZ induced kindling in mice is also a simple and well accepted model of chronic epilepsy. PTZ kindling has been explored for studying epileptogenesis, epilepsy-associated comorbidities, and refractory epilepsy. This review summarizes the potential of PTZ kindling in mice and its modifications for its face, construct, and predictive validity to screen antiepileptogenic drugs, combined or add on novel and safe therapies for treatment of epilepsy-associated depression and cognitive impairment as well as effective interventions for pharmacoresistant epilepsy.
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Affiliation(s)
- Tanveer Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, 147002, India
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, 77807, USA
| | - Awanish Mishra
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, 147002, India
- Department of Pharmacology and Toxicology , National Institute of Pharmaceutical Education and Research , Guwahati , Changsari, Kamrup , 781101 , Assam , India
| | - Rajesh Kumar Goel
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, 147002, India.
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Singh T, Goel RK. Epilepsy Associated Depression: An Update on Current Scenario, Suggested Mechanisms, and Opportunities. Neurochem Res 2021; 46:1305-1321. [PMID: 33665775 DOI: 10.1007/s11064-021-03274-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/07/2021] [Accepted: 02/10/2021] [Indexed: 12/21/2022]
Abstract
Depression is one of the most frequent psychiatric comorbidities associated with epilepsy having a major impact on the patient's quality of life. Several screening tools are available to identify and follow up psychiatric disorders in epilepsy. Out of various psychiatric disorders, people with epilepsy (PWE) are at greater risk of developing depression. This bidirectional relationship further hinders pharmacotherapy of comorbid depression in PWE as some antiepileptic drugs (AEDs) worsen associated depression and coadministration of existing antidepressants (ADs) to alleviate comorbid depression has been reported to worsen seizures. Selective serotonin reuptake inhibitors (SSRIs) and selective serotonin and norepinephrine reuptake inhibitors (SNRIs) are first choice of ADs and are considered safe in PWE, but there are no high-quality evidences. Similar to observations in people with depression, PWE also showed pharmacoresistant to available SSRI/SNRIs, which further complicates the disease prognosis. Randomized double-blind placebo-controlled clinical trials are necessary to report efficacy and safety of available ADs in PWE. We should also move beyond ADs, and therefore, we reviewed common pathological mechanisms such as neuroinflammation, dysregulated hypothalamus pituitary adrenal (HPA) axis, altered neurogenesis, and altered tryptophan metabolism responsible for coexistent relationship of epilepsy and depression. Based on these common pertinent pathways involved in the genesis of epilepsy and depression, we suggested novel targets and therapeutic approaches for safe management of comorbid depression in epilepsy.
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Affiliation(s)
- Tanveer Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India
| | - Rajesh Kumar Goel
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India.
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Heischmann S, Gano LB, Quinn K, Liang LP, Klepacki J, Christians U, Reisdorph N, Patel M. Regulation of kynurenine metabolism by a ketogenic diet. J Lipid Res 2018; 59:958-966. [PMID: 29605816 PMCID: PMC5983405 DOI: 10.1194/jlr.m079251] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 03/08/2018] [Indexed: 11/20/2022] Open
Abstract
Ketogenic diets (KDs) are increasingly utilized as treatments for epilepsy, other neurological diseases, and cancer. Despite their long history in suppressing seizures, the distinct molecular mechanisms of action of KDs are still largely unknown. The goal of this study was to identify key metabolites and pathways altered in the hippocampus and plasma of rats fed a KD versus control diet (CD) either ad libitum or calorically restricted to 90% of the recommended intake. This was accomplished using a combination of targeted methods and untargeted MS-based metabolomics analyses. Various metabolites of and related to the tryptophan (TRP) degradation pathway, such as kynurenine (KYN), kynurenic acid as well as enzyme cofactors, showed significant changes between groups fed different diets and/or calorie amounts in plasma and/or the hippocampus. KYN was significantly downregulated in both matrices in animals of the CD-calorically restricted, KD-ad libitum, and KD-calorically restricted groups compared with the CD-ad libitum group. Our data suggest that the TRP degradation pathway is a key target of the KD.
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Affiliation(s)
- Svenja Heischmann
- Department of Pharmaceutical Sciences, School of Pharmacy University of Colorado Denver, Aurora, CO 80045
| | - Lindsey B Gano
- Department of Pharmaceutical Sciences, School of Pharmacy University of Colorado Denver, Aurora, CO 80045
| | - Kevin Quinn
- Department of Pharmaceutical Sciences, School of Pharmacy University of Colorado Denver, Aurora, CO 80045
| | - Li-Ping Liang
- Department of Pharmaceutical Sciences, School of Pharmacy University of Colorado Denver, Aurora, CO 80045
| | - Jacek Klepacki
- iC42 Clinical Research and Development, Anschutz Medical Campus, University of Colorado Denver, Aurora, CO 80045
| | - Uwe Christians
- iC42 Clinical Research and Development, Anschutz Medical Campus, University of Colorado Denver, Aurora, CO 80045
| | - Nichole Reisdorph
- Department of Pharmaceutical Sciences, School of Pharmacy University of Colorado Denver, Aurora, CO 80045
| | - Manisha Patel
- Department of Pharmaceutical Sciences, School of Pharmacy University of Colorado Denver, Aurora, CO 80045.
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Singh T, Bagga N, Kaur A, Kaur N, Gawande DY, Goel RK. Agmatine for combined treatment of epilepsy, depression and cognitive impairment in chronic epileptic animals. Biomed Pharmacother 2017; 92:720-725. [PMID: 28586743 DOI: 10.1016/j.biopha.2017.05.085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/17/2017] [Accepted: 05/17/2017] [Indexed: 12/17/2022] Open
Abstract
Epilepsy is fourth most common neurological disorders associated with depression and cognitive deficits. As per present scenario, none of the antiseizure drugs have been reported successful to have ameliorative effect on epilepsy associated depression and cognitive deficits. Thus, the study was envisioned to assess an ameliorative potential of agmatine on epilepsy and its efficacy and safety for management of associated depression and cognitive deficits. The animals were made epileptic employing pentylenetetrazole (35mg/kg i.p. every 48±2h) kindling model of epilepsy and subsequently were treated with vehicle, valproic acid (300mg/kg/day i.p.) and agmatine (2.5, 5, and 10mg/kg)/day/i.p. for 15days. Except naïve, all the groups were challenged with same pentylenetetrazole dose as employed during kindling on days 5, 10, and 15 to evaluate seizure severity. Two hours after seizure severity test, tail suspension test and passive shock avoidance paradigm was employed to evaluate depression and cognitive behavior respectively. Results suggested that epileptic animals were significantly associated with depression and cognitive impairment. Chronic valproate treatment significantly reduced seizure severity, but was found unable to mitigate depression and cognitive deficits. However, agmatine treatment dose dependently ameliorated seizure severity as well as associated depression and cognitive deficits. On 15th day, animals were euthanized and pertinent neurochemical estimations were carried out in cortical and hippocampal areas of the mice brain. Thus, study concluded that agmatine ameliorated seizure severity, depression and cognitive impairment in epileptic animals, possibly via restoring glutamate-GABA neurotransmission and serotonin synthesis with decreased nitrosative stress.
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Affiliation(s)
- Tanveer Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India
| | - Neetu Bagga
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India
| | - Anureet Kaur
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India
| | - Navjot Kaur
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India
| | - Dinesh Yugraj Gawande
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India; Division of Neuroscience, Department of Pharmacology, Smt. Kishoritai Bhoyar College of Pharmacy, Kamptee, Nagpur, Maharashtra, India
| | - Rajesh Kumar Goel
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India.
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Abstract
Tryptophan-2, 3-dioxygenase (TDO) is a heme-containing protein catalyzing the first reaction in the kynurenine pathway, which incorporates oxygen into the indole moiety of tryptophan and catalyzes it into kynurenine (KYN). The activation of TDO results in the depletion of tryptophan and the accumulation of kynurenine and its metabolites. These metabolites can affect the function of neurons and inhibit the proliferation of T cells. Increasing evidence demonstrates that TDO is a potential therapeutic target in the treatment of brain diseases as well as in the antitumor and transplant fields. Despite its growing popularity, there are few reviews only focusing on TDO. Hence, we herein review TDO by providing a comprehensive overview of TDO, including its biological functions as well as the evolution, structure and catalytic process of TDO. Additionally, this review will focus on the role of TDO in the pathology of three groups of brain diseases: Schizophrenia, Alzheimer's disease (AD) and Glioma. Finally, we will also provide an opinion regarding the future developmental directions of TDO in brain diseases, especially whether TDO has a potential role in other brain diseases as well as the development and applications of TDO inhibitors as treatments.
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Affiliation(s)
- Cheng-Peng Yu
- The Second Clinic Medical College, School of Medicine, Nanchang University, Nanchang, China
| | - Ze-Zheng Pan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanchang University, Nanchang, China
| | - Da-Ya Luo
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanchang University, Nanchang, China.
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Evidence in support of using a neurochemistry approach to identify therapy for both epilepsy and associated depression. Epilepsy Behav 2016; 61:248-257. [PMID: 27423076 DOI: 10.1016/j.yebeh.2016.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 05/04/2016] [Accepted: 05/04/2016] [Indexed: 12/19/2022]
Abstract
The present study aimed to develop a neurochemistry-based single or adjuvant therapy approach for comprehensive management of epilepsy and associated depression employing pentylenetetrazole-kindled animals. Kindling was induced in two-month-old male Swiss albino mice by administering a subconvulsant pentylenetetrazole dose (35mg/kg, i.p.) at an interval of 48±2h. These kindled animals were treated with saline and sodium valproate (300mg/kg/day, i.p.) for 15days. Except for the naïve group, all other groups were challenged with pentylenetetrazole (35mg/kg, i.p.) on days 5, 10, and 15 to evaluate the seizure severity. Depression was evaluated in all experimental groups after normalization of locomotor activity, using tail suspension and forced swim test on days 1, 5, 10, and 15. Four hours after behavioral evaluations on day 15, all animals were euthanized to collect their serum and discrete brain parts. Corticosterone levels were estimated in all the experimental groups as a marker of a dysregulated hypothalamus pituitary adrenal axis. Neurochemical alterations (norepinephrine, dopamine, tryptophan, kynurenine, serotonin, glutamate, GABA, and total nitrate levels) were also estimated in the cortical and hippocampal areas of the mouse brain. Results revealed that saline-treated kindled animals were associated with significant depression and altered neurochemical milieu in comparison with naïve animals. Chronic valproate treatment in kindled animals significantly reduced seizure severity score bud did not ameliorate associated depression or completely restore altered biochemical and neurochemical milieu. Based on the observation of neurochemical changes in all the groups, we propose that restoration of altered neurochemical milieu, elevated indoleamine 2,3-dioxygenase enzyme activity, and corticosterone levels using pharmacological tools with/out valproic acid may be explored for management of both epilepsy and comorbid depression.
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Singh T, Goel RK. Adjuvant indoleamine 2,3-dioxygenase enzyme inhibition for comprehensive management of epilepsy and comorbid depression. Eur J Pharmacol 2016; 784:111-20. [PMID: 27189423 DOI: 10.1016/j.ejphar.2016.05.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 01/22/2023]
Abstract
Epilepsy is one of the major neurological disorders frequently associated with psychiatric disorders such as depression. Alteration of tryptophan metabolism towards kynurenine pathway may be one of the plausible reasons for association of depression in epilepsy. Hence, this study was envisaged to evaluate the dose dependent inhibition of indoleamine 2,3-dioxygenase (IDO) enzyme (responsible for shifting tryptophan metabolism) employing minocycline with valproic acid for comprehensive management of epilepsy and comorbid depression. Kindling was induced in male swiss albino mice by administration of pentylenetetrazole subconvulsive dose (35mg/kg, i.p.) at an interval of 48±2h. Kindled animals were treated with saline, valproate (300mg/kg/day i.p.), valproate in combination with different doses of minocycline (10mg/kg; 20mg/kg; 40mg/kg)/day i.p. and minocycline per se (40mg/kg/day i.p.) for 15 days. Except naïve, all the groups were challenged with pentylenetetrazole (35mg/kg i.p.) on day 5, 10, and 15 to evaluate the seizure severity score. Depression was evaluated in all experimental groups using tail suspension and forced swim test on days 1, 5, 10 and 15, 2h after pentylenetetrazole challenge. Results suggested that saline treated kindled animals were significantly associated with depression. Chronic valproate treatment significantly reduced seizure severity score but unable to ameliorate the associated depression. Minocycline supplementation with valproic acid dose dependently ameliorated depression associated with epilepsy. Neurochemical and biochemical findings also supported the behavioural findings of the study. Thus, our results suggested that supplementation of IDO enzyme inhibitors with valproic acid could be explored further for comprehensive management of epilepsy and associated depression.
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Affiliation(s)
- Tanveer Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala 147002, Punjab, India
| | - Rajesh Kumar Goel
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala 147002, Punjab, India.
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Campbell BM, Charych E, Lee AW, Möller T. Kynurenines in CNS disease: regulation by inflammatory cytokines. Front Neurosci 2014; 8:12. [PMID: 24567701 PMCID: PMC3915289 DOI: 10.3389/fnins.2014.00012] [Citation(s) in RCA: 250] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 01/20/2014] [Indexed: 12/27/2022] Open
Abstract
The kynurenine pathway (KP) metabolizes the essential amino acid tryptophan and generates a number of neuroactive metabolites collectively called the kynurenines. Segregated into at least two distinct branches, often termed the “neurotoxic” and “neuroprotective” arms of the KP, they are regulated by the two enzymes kynurenine 3-monooxygenase and kynurenine aminotransferase, respectively. Interestingly, several enzymes in the pathway are under tight control of inflammatory mediators. Recent years have seen a tremendous increase in our understanding of neuroinflammation in CNS disease. This review will focus on the regulation of the KP by inflammatory mediators as it pertains to neurodegenerative and psychiatric disorders.
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Affiliation(s)
- Brian M Campbell
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
| | - Erik Charych
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
| | - Anna W Lee
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
| | - Thomas Möller
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
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The concentration of cell-free DNA in focal epilepsy. Epilepsy Res 2013; 105:292-8. [DOI: 10.1016/j.eplepsyres.2013.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 01/21/2013] [Accepted: 03/17/2013] [Indexed: 12/21/2022]
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Abstract
The lifetime risk of having epileptic seizures is profoundly increased in patients with cancer: about 20% of all patients with systemic cancer may develop brain metastases. These patients and those with primary brain tumours have a lifetime risk of epilepsy of 20-80%. Moreover, exposure to chemotherapy or radiotherapy to the brain, cancer-related metabolic disturbances, stroke, and infection can provoke seizures. The management of epilepsy in patients with cancer includes diagnosis and treatment of the underlying cerebral pathological changes, secondary prophylaxis with antiepileptic drugs, and limiting of the effect of epilepsy and its treatment on the efficacy and tolerability of anticancer treatments, cognitive function, and quality of life. Because of the concern of drug-drug interactions, the pharmacological approach to epilepsy requires a multidisciplinary approach, specifically in a setting of rapidly increasing choices of agents both to treat cancer and cancer-associated epilepsy.
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Affiliation(s)
- Michael Weller
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland.
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High concentration of immunoglobulin A is associated with temporal lobe epilepsy. Epilepsy Res 2012; 103:54-61. [PMID: 22749917 DOI: 10.1016/j.eplepsyres.2012.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 05/17/2012] [Accepted: 06/09/2012] [Indexed: 11/23/2022]
Abstract
INTRODUCTION Dysfunction of immunoglobulins (Igs) has been detected in association with antiepileptic drugs (AEDs) and in newly diagnosed epilepsy patients. The aim of this study was to evaluate the effect of clinical features and the current or past use of AEDs on serum Ig concentrations in a well-examined group of patients with refractory epilepsy. PATIENTS AND METHODS Using a nephelometric method, concentrations of IgA, IgG and IgM were analyzed in the sera of 257 patients with refractory epilepsy, 15 patients with controlled epilepsy and 584 healthy control subjects. RESULTS A low IgA concentration was found in 8.8% of the patients with epilepsy compared with 1.9% of the control subjects. High concentrations of IgA were associated with temporal lobe epilepsy (TLE) compared with other epilepsy types (p=0.042). The high concentrations of IgA (p=0.042), low concentrations of IgG (p=0.002), and high concentrations of IgG (p=0.008) were also associated with autoimmune diseases. The use of lamotrigine, nitrazepam, oxcarbazepine, topiramate and valproic acid was associated with alterations in Ig concentrations. Current use of topiramate was associated with high serum IgG and IgM concentrations (OR 10.39; 95% CI: 3.08-35.04 and OR 7.02; 95% CI: 1.25-39.55, respectively). DISCUSSION The finding of high serum IgA concentration in patients with TLE strengthens the previously found association of immunological activity in the epileptic temporal lobe rather than other brain regions. The newly observed immunological effects of topiramate are important to proper AED choice in patients with refractory epilepsy.
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Alkonyi B, Mittal S, Zitron I, Chugani DC, Kupsky WJ, Muzik O, Chugani HT, Sood S, Juhász C. Increased tryptophan transport in epileptogenic dysembryoplastic neuroepithelial tumors. J Neurooncol 2011; 107:365-72. [PMID: 22048879 DOI: 10.1007/s11060-011-0750-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 10/24/2011] [Indexed: 12/26/2022]
Abstract
Dysembryoplastic neuroepithelial tumors (DNTs) are typically hypometabolic but can show increased amino acid uptake on positron emission tomography (PET). To better understand mechanisms of amino acid accumulation in epileptogenic DNTs, we combined quantitative α-[(11)C]methyl-L: -tryptophan (AMT) PET with tumor immunohistochemistry. Standardized uptake values (SUVs) of AMT and glucose were measured in 11 children with temporal lobe DNT. Additional quantification for AMT transport and metabolism was performed in 9 DNTs. Tumor specimens were immunostained for the L: -type amino acid transporter 1 (LAT1) and indoleamine 2,3-dioxygenase (IDO), a key enzyme of the immunomodulatory kynurenine pathway. All 11 tumors showed glucose hypometabolism, while mean AMT SUVs were higher than normal cortex in eight DNTs. Further quantification showed increased AMT transport in seven and high AMT metabolic rates in three DNTs. Two patients showing extratumoral cortical increases of AMT SUV had persistent seizures despite complete tumor resection. Resected DNTs showed moderate to strong LAT1 and mild to moderate IDO immunoreactivity, with the strongest expression in tumor vessels. These results indicate that accumulation of tryptophan in DNTs is driven by high amino acid transport, mediated by LAT1, which can provide the substrate for tumoral tryptophan metabolism through the kynurenine pathway, that can produce epileptogenic metabolites. Increased AMT uptake can extend to extratumoral cortex, and presence of such cortical regions may increase the likelihood of recurrent seizures following surgical excision of DNTs.
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Affiliation(s)
- Bálint Alkonyi
- PET Center, Children's Hospital of Michigan, 3901 Beaubien Blvd, Detroit, MI 48201, USA
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