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Regazzoni L. State of the Art in the Development of Human Serum Carnosinase Inhibitors. Molecules 2024; 29:2488. [PMID: 38893364 PMCID: PMC11173852 DOI: 10.3390/molecules29112488] [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: 04/16/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/21/2024] Open
Abstract
Human serum carnosinase is an enzyme that operates the preferential hydrolysis of dipeptides with a C-terminus histidine. Only higher primates excrete such an enzyme in serum and cerebrospinal fluid. In humans, the serum hydrolytic rate has high interindividual variability owing to gene polymorphism, although age, gender, diet, and also diseases and surgical interventions can modify serum activity. Human genetic diseases with altered carnosinase activity have been identified and associated with neurological disorders and age-related cognitive decline. On the contrary, low peripheral carnosinase activity has been associated with kidney protection, especially in diabetic nephropathy. Therefore, serum carnosinase is a druggable target for the development of selective inhibitors. However, only one molecule (i.e., carnostatine) has been discovered with the purpose of developing serum carnosinase inhibitors. Bestatin is the only inhibitor reported other than carnostatine, although its activity is not selective towards serum carnosinase. Herein, we present a review of the most critical findings on human serum carnosinase, including enzyme expression, localization and substrate selectivity, along with factors affecting the hydrolytic activity, its implication in human diseases and the properties of known inhibitors of the enzyme.
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Affiliation(s)
- Luca Regazzoni
- Department of Pharmaceutical Sciences, University of Milan, Via Mangiagalli 25, 20133 Milan, Italy
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Landheer K, Prinsen H, Petroff OA, Rothman DL, Juchem C. Elevated homocarnosine and GABA in subject on isoniazid as assessed through 1H MRS at 7T. Anal Biochem 2020; 599:113738. [PMID: 32302606 DOI: 10.1016/j.ab.2020.113738] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/09/2020] [Accepted: 04/11/2020] [Indexed: 12/27/2022]
Abstract
Typical magnetic resonance spectroscopy J-editing methods designed to quantify GABA suffer from contamination of both overlapping macromolecules and homocarnosine signal, introducing potential confounds. The aim of this study was to develop a novel method to assess accurately both the relative concentrations of homocarnosine as well as GABA free from overlapping creatine, homocarnosine and macromolecule signal. A novel method which utilized the combination of echo time STEAM and MEGA-sLASER magnetic resonance spectroscopy experiments at 7T were used to quantify the concentration of GABA and homocarnsoine independently, which are typically quantified in tandem. The metabolites GABA and homocarnosine were measured in brain of 6 healthy control subjects, and in a single subject medicated with isoniazid. It was found that (16.6±10.2)% of the supposed GABA signal in the brain originated from homocarnosine, and that isoniazid caused significantly elevated concentration of GABA and homocarnosine in a single subject compared to controls.
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Affiliation(s)
- Karl Landheer
- Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, New York, NY, USA.
| | - Hetty Prinsen
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Ognen A Petroff
- Department of Neurology, Yale University, New Haven, CT, USA
| | - Douglas L Rothman
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Christoph Juchem
- Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, New York, NY, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Department of Neurology, Yale University, New Haven, CT, USA; Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
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Kumrungsee T, Arima T, Sato K, Komaru T, Sato M, Oishi Y, Egusa A, Yanaka N. Dietary GABA induces endogenous synthesis of a novel imidazole peptide homocarnosine in mouse skeletal muscles. Amino Acids 2020; 52:743-753. [PMID: 32361909 DOI: 10.1007/s00726-020-02848-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 04/29/2020] [Indexed: 10/24/2022]
Abstract
Carnosine (β-alanyl-L-histidine) is an imidazole dipeptide present at high concentrations in skeletal muscles, where it plays a beneficial role. However, oral intake of carnosine or β-alanine to increase skeletal muscle carnosine levels has disadvantages such as low efficiency and side effects. Therefore, we proposed homocarnosine (γ-aminobutyryl-L-histidine) as a novel alternative imidazole peptide for skeletal muscle based on its structural similarity to carnosine. To induce endogenous homocarnosine synthesis in skeletal muscles, mice were fed a basal diet mixed with 0, 0.5, 2, or 5% γ-aminobutyric acid (GABA) for 6 weeks. As expected, in the control group (0% GABA), GABA and homocarnosine were present in trace concentrations. Skeletal muscle homocarnosine levels were significantly increased in the 2% and 5% GABA intake groups (tenfold, P < 0.01 and 53-fold, P < 0.01; respectively) relative to those of the control group, whereas 0.5% GABA intake induced no such effect. GABA intake had no effect on the levels of carnosine, anserine, and β-alanine. Vigabatrin (inhibitor of GABA transaminase (GABA-T)) administration to mice receiving 2% GABA intake for 2 weeks led to GABA-T inhibition in the liver. Subsequently, a 43-fold increase in circulating GABA levels and a tendency increase in skeletal muscle homocarnosine levels were observed. Therefore, skeletal muscle homocarnosine synthesis can be induced by supplying its substrate GABA in tissues. As GABA availability is tightly regulated by GABA-T via GABA degradation, inhibitors of GABA or β-alanine degradation could be novel potential interventions for increasing skeletal muscle imidazole dipeptides.
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Affiliation(s)
- Thanutchaporn Kumrungsee
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, 1-4-4 Kagamiyama, Hiroshima, 739-8528, Japan.
| | - Takeshi Arima
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, 1-4-4 Kagamiyama, Hiroshima, 739-8528, Japan
| | - Kanako Sato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, 1-4-4 Kagamiyama, Hiroshima, 739-8528, Japan
| | - Takumi Komaru
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, 1-4-4 Kagamiyama, Hiroshima, 739-8528, Japan
| | - Mikako Sato
- NH Foods Ltd. R&D Center, Tsukuba, Ibaraki, 300-2646, Japan
| | - Yasuyuki Oishi
- NH Foods Ltd. R&D Center, Tsukuba, Ibaraki, 300-2646, Japan
| | - Ai Egusa
- Department of Food Science and Technology, Nippon Veterinary and Life Science University, Tokyo, 180-8602, Japan
| | - Noriyuki Yanaka
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, 1-4-4 Kagamiyama, Hiroshima, 739-8528, Japan.
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Chmielewska K, Dzierzbicka K, Inkielewicz-Stępniak I, Przybyłowska M. Therapeutic Potential of Carnosine and Its Derivatives in the Treatment of Human Diseases. Chem Res Toxicol 2020; 33:1561-1578. [PMID: 32202758 DOI: 10.1021/acs.chemrestox.0c00010] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Despite significant progress in the pathogenesis, diagnosis, treatment, and prevention of cancer and neurodegenerative diseases, their occurrence and mortality are still high around the world. The resistance of cancer cells to the drugs remains a significant problem in oncology today, while in the case of neuro-degenerative diseases, therapies reversing the process are still yet to be found. Furthermore, it is important to seek new chemotherapeutics reversing side effects of currently used drugs or helping them perform their function to inhibit progression of the disease. Carnosine, a dipeptide constisting of β-alanine and l-histidine, has a variety of functions to mention: antioxidant, antiglycation, and reducing the toxicity of metal ions. It has therefore been proposed to act as a therapeutic agent for many pathological states. The aim of this paper was to find if carnosine and its derivatives can be helpful in treating various diseases. Literature search presented in this review includes review and original papers found in SciFinder, PubMed, and Google Scholar. Searches were based on substantial keywords concerning therapeutic usage of carnosine and its derivatives in several diseases including neurodegenerative disorders and cancer. In this paper, we review articles and find that carnosine and its derivatives are potential therapeutic agents in many diseases including cancer, neurodegenerative diseases, diabetes, and schizophrenia. Carnosine and its derivatives can be used in treating neurodegenerative diseases, cancer, diabetes, or schizophrenia, although their usage is limited. Therefore, there's an urge to synthesize and analyze new substances, overcoming the limitation of carnosine itself.
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Affiliation(s)
- Klaudia Chmielewska
- Department of Organic Chemistry, Faculty of Chemistry, Gdansk University of Technology, Gdansk 80-233, Poland
| | - Krystyna Dzierzbicka
- Department of Organic Chemistry, Faculty of Chemistry, Gdansk University of Technology, Gdansk 80-233, Poland
| | - Iwona Inkielewicz-Stępniak
- Department of Medical Chemistry, Faculty of Medicine, Medical University of Gdansk, Gdansk 80-211, Poland
| | - Maja Przybyłowska
- Department of Organic Chemistry, Faculty of Chemistry, Gdansk University of Technology, Gdansk 80-233, Poland
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Huang J, Wang T, Yu D, Fang X, Fan H, Liu Q, Yi G, Yi X, Liu Q. l-Homocarnosine attenuates inflammation in cerebral ischemia-reperfusion injury through inhibition of nod-like receptor protein 3 inflammasome. Int J Biol Macromol 2018; 118:357-364. [PMID: 29890246 DOI: 10.1016/j.ijbiomac.2018.06.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 10/14/2022]
Abstract
We investigated the therapeutic effects of l-homocarnosine against inflammation in a rat model of cerebral ischemia-reperfusion injury. Rats were grouped into control, middle cerebral artery occlusion (MCAO), 0.5 mM l-homocarnosine + MCAO, and 1 mM l-homocarnosine + MCAO treatment groups. Superoxide dismutase (SOD), glutathione peroxidase (Gpx), catalase, lipid peroxidation, and reduced glutathione (GSH) levels were measured. Neurological scores were assessed, and histopathology, scanning electron microscopy (SEM), and fluorescence microscopy analyses were conducted. The mRNA expression levels of nod-like receptor protein 3 (NLRP3), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6) and protein expression levels of NLRP3 were assessed. l-Homocarnosine supplementation substantially increased SOD, catalase, Gpx, and GSH levels, whereas it reduced the levels of lipid peroxidation relative to MCAO rats. l-Homocarnosine significantly reduced the infarct area and neurological deficit score, as well as histopathological alteration, apoptosis, and necrosis in brain tissue. The mRNA expression levels of NLRP3, TNF-α, and IL-6 were increased in MCAO rats, whereas l-homocarnosine supplementation reduced mRNA expression by >40%, and NLRP3 protein expression was reduced by >30% in 1 mM l-homocarnosine-treated MCAO rats. We propose that l-homocarnosine exerts a protective effect in cerebral ischemia-reperfusion injury-induced rats by downregulating NLRP3 expression.
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Affiliation(s)
- Jing Huang
- Department of Pharmacology, Hainan Medical University, Haikou, Hainan 571199, China
| | - Tao Wang
- International Nursing School, Hainan Medical University, Haikou, Hainan 571199, China
| | - Daorui Yu
- Department of Pharmacology, Hainan Medical University, Haikou, Hainan 571199, China
| | - Xingyue Fang
- Department of Pharmacology, Hainan Medical University, Haikou, Hainan 571199, China
| | - Haofei Fan
- Department of Pharmacology, Hainan Medical University, Haikou, Hainan 571199, China
| | - Qiang Liu
- Department of Pharmacology, Hainan Medical University, Haikou, Hainan 571199, China
| | - Guohui Yi
- Department of Pharmacology, Hainan Medical University, Haikou, Hainan 571199, China
| | - Xinan Yi
- Department of Anatomy, School of Basic Medicine and Life Science, Hainan Medical University, Haikou, Hainan 571199, China
| | - Qibing Liu
- Department of Pharmacology, Hainan Medical University, Haikou, Hainan 571199, China.
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van Veenendaal TM, IJff DM, Aldenkamp AP, Hofman PAM, Vlooswijk MCG, Rouhl RPW, de Louw AJ, Backes WH, Jansen JFA. Metabolic and functional MR biomarkers of antiepileptic drug effectiveness: A review. Neurosci Biobehav Rev 2015; 59:92-9. [PMID: 26475992 DOI: 10.1016/j.neubiorev.2015.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 10/07/2015] [Accepted: 10/12/2015] [Indexed: 12/30/2022]
Abstract
As a large number of patients with epilepsy do not respond favorably to antiepileptic drugs (AEDs), a better understanding of treatment failure and the cause of adverse side effects is required. The working mechanisms of AEDs also alter neurotransmitter concentrations and brain activity, which can be measured using MR spectroscopy and functional MR imaging, respectively. This review presents an overview of clinical research of MR spectroscopy and functional MR imaging studies to the effects of AEDs on the brain. Despite the scarcity of studies associating MR findings to the effectiveness of AEDs, the current research shows clear potential regarding this matter. Several GABAergic AEDs have been shown to increase the GABA concentration, which was related to seizure reductions, while language problems due to topiramate have been associated with altered activation patterns measured with functional MR imaging. MR spectroscopy and functional MR imaging provide biomarkers that may predict individual treatment outcomes, and enable the assessment of mechanisms of treatment failure and cognitive side effects.
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Affiliation(s)
- Tamar M van Veenendaal
- Departments of Radiology and Nuclear Medicine, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Dominique M IJff
- School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Epilepsy Center Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands
| | - Albert P Aldenkamp
- School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Epilepsy Center Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands; Department of Neurology, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands; Department of Neurology, Gent University Hospital, De Pintelaan 185, 9000 Gent, Belgium; Faculty of Electrical Engineering, University of Technology Eindhoven, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Paul A M Hofman
- Departments of Radiology and Nuclear Medicine, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Epilepsy Center Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands
| | - Marielle C G Vlooswijk
- School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Epilepsy Center Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands; Department of Neurology, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands
| | - Rob P W Rouhl
- School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands; Epilepsy Center Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands; Department of Neurology, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands
| | - Anton J de Louw
- Epilepsy Center Kempenhaeghe, PO Box 61, 5590 AB Heeze, The Netherlands; Department of Neurology, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands; Faculty of Electrical Engineering, University of Technology Eindhoven, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Walter H Backes
- Departments of Radiology and Nuclear Medicine, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Jacobus F A Jansen
- Departments of Radiology and Nuclear Medicine, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands.
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Cai K, Nanga RPR, Lamprou L, Schinstine C, Elliott M, Hariharan H, Reddy R, Epperson CN. The impact of gabapentin administration on brain GABA and glutamate concentrations: a 7T ¹H-MRS study. Neuropsychopharmacology 2012; 37:2764-71. [PMID: 22871916 PMCID: PMC3499716 DOI: 10.1038/npp.2012.142] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Gamma-aminobutyric acid (GABA) and glutamate are implicated in numerous neuropsychiatric and substance abuse conditions, but their spectral overlap with other resonances makes them a challenge to quantify in humans. Gabapentin, marketed for the treatment of seizures and neuropathic pain, has been shown to increase in vivo GABA concentration in the brain of both rodents and humans. Gabapentin effects on glutamate are not known. We conducted a gabapentin (900 mg) challenge in healthy human subjects to confirm and explore its effects on GABA and glutamate concentrations, respectively, and to test the ability of single voxel localized proton magnetic resonance spectroscopy (¹H-MRS) to reliably measure GABA and glutamate in the visual cortex at the ultra-high magnetic field of 7 Tesla. Reproducibility of GABA and glutamate measurements was determined in a comparison group without drug twice within day and 2 weeks apart. Although GABA concentration changes were small both within day (average 5.6%) and between day (average 4.8%), gabapentin administration was associated with an average increase in GABA concentration of 55.7% (6.9-91.0%). Importantly, drug-induced change in GABA levels was inversely correlated to the individual's baseline GABA level (R²=0.72). Mean glutamate concentrations did not change significantly with or without drug administration. In conclusion, localized ¹H-MRS at 7 Tesla can be successfully applied to the measurement of GABA concentration and is sensitive to acute drug-induced changes in cortical GABA. Whether baseline GABA concentrations predict clinical efficacy of gabapentin is an area worthy of exploration.
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Affiliation(s)
- Kejia Cai
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi PR Nanga
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Lisa Lamprou
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Penn Center for Women's Behavioral Wellness, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Claudia Schinstine
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Penn Center for Women's Behavioral Wellness, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Mark Elliott
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Ravinder Reddy
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging (CMROI), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - C Neill Epperson
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Psychiatry, Penn Center for Women's Behavioral Wellness, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Department of Obstetrics and Gynecology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA,Penn Center for Women's Behavioral Wellness, 3535 Market Street, Room 3001, Philadelphia, PA 19104, USA, Tel: +1 215 573-8871, Fax: +1 215 573 8881, E-mail:
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Puts NA, Edden RA. In vivo magnetic resonance spectroscopy of GABA: a methodological review. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2012; 60:29-41. [PMID: 22293397 PMCID: PMC3383792 DOI: 10.1016/j.pnmrs.2011.06.001] [Citation(s) in RCA: 273] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 05/30/2011] [Indexed: 05/06/2023]
Affiliation(s)
- Nicolaas A.J. Puts
- Schools of Bioscience and Psychology, Cardiff University, Park Place, Cardiff, UK
| | - Richard A.E. Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- FM Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- Corresponding author. Address: Russell H. Morgan Department of Radiology and Radiological Science, 600 N Wolfe St., Park 367C, Baltimore, MD 21287, USA. Tel.: +1 410 614 3418. (R.A.E. Edden)
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Conte MM, Victor JD. VEP indices of cortical lateral interactions in epilepsy treatment. Vision Res 2009; 49:898-906. [PMID: 18572221 PMCID: PMC2873633 DOI: 10.1016/j.visres.2008.04.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Revised: 04/10/2008] [Accepted: 04/11/2008] [Indexed: 11/18/2022]
Abstract
We extend Spekreijse's strategy for analyzing lateral interactions in visual evoked potentials (VEPs) to clinical neurophysiologic testing of patients with epilepsy. Stimuli consisted of the radial windmill/dartboard pattern [Ratliff, F., & Zemon, V. (1982). Some new methods for the analysis of lateral interactions that influence the visual evoked potential. In: Bodis-Wollner (Ed.), Evoked potentials, Vol. 388. (pp. 113-124). New York: Annals of the New York Academy of Sciences.] and conventional checkerboards. The fundamental and 2nd-harmonic components of the steady-state responses were used to calculate indices reflecting facilitatory (FI) and suppressive (SI) cortical interactions. We carried out two studies. In the first, VEPs in 38 patients receiving antiepileptic drug (AED) therapy were compared to those of age-matched controls. For three AEDs (tiagabine, topiramate, and felbamate), addition of the drug did not change the FI and SI compared to baseline values or those of normal controls. However, the addition of gabapentin was associated with an increase of the FI, and this change was reversed when the medication was withdrawn. This suggested a medication-specific change in cortical lateral interactions. The second study focused on the effects of neurostimulation therapy. Eleven epilepsy patients receiving chronic vagus nerve stimulation (VNS) treatment were tested. By comparing VEPs recorded with the stimulator on (Stim-ON) and turned off (Stim-OFF) in the same session, we determined that VNS did not have a short-acting effect on lateral interactions. However, when compared with normal controls, the VNS patients had a significantly smaller SI (p<.05), but no difference in the FI, demonstrating the presence of a chronic effect. We conclude that with the appropriate stimuli, VEPs can be used as a measure of cortical lateral interactions in normals and epileptic patients, and demonstrate specific changes in these interactions associated with certain treatment modalities.
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Affiliation(s)
- Mary M Conte
- Department of Neurology and Neuroscience, Weill Cornell Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA.
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Hipkiss AR. Carnosine and its possible roles in nutrition and health. ADVANCES IN FOOD AND NUTRITION RESEARCH 2009; 57:87-154. [PMID: 19595386 DOI: 10.1016/s1043-4526(09)57003-9] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The dipeptide carnosine has been observed to exert antiaging activity at cellular and whole animal levels. This review discusses the possible mechanisms by which carnosine may exert antiaging action and considers whether the dipeptide could be beneficial to humans. Carnosine's possible biological activities include scavenger of reactive oxygen species (ROS) and reactive nitrogen species (RNS), chelator of zinc and copper ions, and antiglycating and anticross-linking activities. Carnosine's ability to react with deleterious aldehydes such as malondialdehyde, methylglyoxal, hydroxynonenal, and acetaldehyde may also contribute to its protective functions. Physiologically carnosine may help to suppress some secondary complications of diabetes, and the deleterious consequences of ischemic-reperfusion injury, most likely due to antioxidation and carbonyl-scavenging functions. Other, and much more speculative, possible functions of carnosine considered include transglutaminase inhibition, stimulation of proteolysis mediated via effects on proteasome activity or induction of protease and stress-protein gene expression, upregulation of corticosteroid synthesis, stimulation of protein repair, and effects on ADP-ribose metabolism associated with sirtuin and poly-ADP-ribose polymerase (PARP) activities. Evidence for carnosine's possible protective action against secondary diabetic complications, neurodegeneration, cancer, and other age-related pathologies is briefly discussed.
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Affiliation(s)
- Alan R Hipkiss
- School of Clinicial and Experimental Medicine, College of Medical and Dental Sciences, The Univeristy of Birmingham, Edgbaston, Birmingham, UK
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