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Uranga RM, Giusto NM, Salvador GA. Iron-Induced Oxidative Injury Differentially Regulates PI3K/Akt/GSK3β Pathway in Synaptic Endings from Adult and Aged Rats. Toxicol Sci 2009; 111:331-44. [DOI: 10.1093/toxsci/kfp152] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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103
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Aquino D, Bizzi A, Grisoli M, Garavaglia B, Bruzzone MG, Nardocci N, Savoiardo M, Chiapparini L. Age-related Iron Deposition in the Basal Ganglia: Quantitative Analysis in Healthy Subjects. Radiology 2009; 252:165-72. [DOI: 10.1148/radiol.2522081399] [Citation(s) in RCA: 217] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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104
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Kang JH. Ferritin enhances salsolinol-mediated DNA strand breakage: Protection by carnosine and related compounds. Toxicol Lett 2009; 188:20-5. [DOI: 10.1016/j.toxlet.2009.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 02/09/2009] [Accepted: 02/12/2009] [Indexed: 12/26/2022]
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105
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Khalil M, Enzinger C, Langkammer C, Tscherner M, Wallner-Blazek M, Jehna M, Ropele S, Fuchs S, Fazekas F. Quantitative assessment of brain iron by R2* relaxometry in patients with clinically isolated syndrome and relapsing–remitting multiple sclerosis. Mult Scler 2009; 15:1048-54. [DOI: 10.1177/1352458509106609] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Increased iron deposition has been implicated in the pathophysiology of multiple sclerosis (MS), based on visual analysis of signal reduction on T2-weighted images. R2* relaxometry allows to assess brain iron accumulation quantitatively. Objective To investigate regional brain iron deposition in patients with a clinically isolated syndrome (CIS) or relapsing–remitting MS (RRMS) and its associations with demographical, clinical, and conventional magnetic resonance imaging (MRI) parameters. Methods We studied 69 patients (CIS, n = 32; RRMS, n = 37) with 3T MRI and analyzed regional R2* relaxation rates and their correlations with age, disease duration, disability, T2 lesion load, and normalized brain volumes. Results Basal ganglia R2* relaxation rates increased in parallel with age ( r = 0.3–0.6; P < 0.01) and were significantly higher in RRMS than in CIS ( P < 0.05). Using multivariate linear regression analysis, the rate of putaminal iron deposition was independently predicted by the patients’ age, disease duration, and gray matter atrophy. Conclusions Quantitative assessment by R2* relaxometry suggests increased iron deposition in the basal ganglia of MS patients, which is associated with disease duration and brain atrophy. This technique together with long-term follow-up thus appears suited to clarify whether regional iron accumulation contributes to MS morbidity or merely reflects an epiphenomenon.
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Affiliation(s)
- M Khalil
- Department of Neurology and Department of Radiology (Division of Neuroradiology), Medical University of Graz, Graz, Austria
| | - C Enzinger
- Department of Neurology and Department of Radiology (Division of Neuroradiology), Medical University of Graz, Graz, Austria
| | - C Langkammer
- Department of Neurology and Department of Radiology (Division of Neuroradiology), Medical University of Graz, Graz, Austria
| | - M Tscherner
- Department of Neurology and Department of Radiology (Division of Neuroradiology), Medical University of Graz, Graz, Austria
| | - M Wallner-Blazek
- Department of Neurology and Department of Radiology (Division of Neuroradiology), Medical University of Graz, Graz, Austria
| | - M Jehna
- Department of Neurology and Department of Radiology (Division of Neuroradiology), Medical University of Graz, Graz, Austria
| | - S Ropele
- Department of Neurology and Department of Radiology (Division of Neuroradiology), Medical University of Graz, Graz, Austria
| | - S Fuchs
- Department of Neurology and Department of Radiology (Division of Neuroradiology), Medical University of Graz, Graz, Austria
| | - F Fazekas
- Department of Neurology and Department of Radiology (Division of Neuroradiology), Medical University of Graz, Graz, Austria
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Jellinger KA. Recent advances in our understanding of neurodegeneration. J Neural Transm (Vienna) 2009; 116:1111-62. [DOI: 10.1007/s00702-009-0240-y] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 05/05/2009] [Indexed: 12/12/2022]
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Trends in the molecular pathogenesis and clinical therapeutics of common neurodegenerative disorders. Int J Mol Sci 2009; 10:2510-2557. [PMID: 19582217 PMCID: PMC2705504 DOI: 10.3390/ijms10062510] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 04/28/2009] [Accepted: 05/05/2009] [Indexed: 12/11/2022] Open
Abstract
The term neurodegenerative disorders, encompasses a variety of underlying conditions, sporadic and/or familial and are characterized by the persistent loss of neuronal subtypes. These disorders can disrupt molecular pathways, synapses, neuronal subpopulations and local circuits in specific brain regions, as well as higher-order neural networks. Abnormal network activities may result in a vicious cycle, further impairing the integrity and functions of neurons and synapses, for example, through aberrant excitation or inhibition. The most common neurodegenerative disorders are Alzheimer’s disease, Parkinson’s disease, Amyotrophic Lateral Sclerosis and Huntington’s disease. The molecular features of these disorders have been extensively researched and various unique neurotherapeutic interventions have been developed. However, there is an enormous coercion to integrate the existing knowledge in order to intensify the reliability with which neurodegenerative disorders can be diagnosed and treated. The objective of this review article is therefore to assimilate these disorders’ in terms of their neuropathology, neurogenetics, etiology, trends in pharmacological treatment, clinical management, and the use of innovative neurotherapeutic interventions.
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Todorich B, Pasquini JM, Garcia CI, Paez PM, Connor JR. Oligodendrocytes and myelination: The role of iron. Glia 2009; 57:467-78. [PMID: 18837051 DOI: 10.1002/glia.20784] [Citation(s) in RCA: 424] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Bozho Todorich
- Department of Neurosurgery, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033-0850, USA
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109
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Lou M, Lieb K, Selim M. The relationship between hematoma iron content and perihematoma edema: an MRI study. Cerebrovasc Dis 2009; 27:266-71. [PMID: 19202331 DOI: 10.1159/000199464] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 10/26/2008] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Iron neurotoxicity has been linked to delayed neuronal injury and edema formation after intracerebral hemorrhage (ICH). We have previously shown that serum ferritin, an indicator of body iron load, correlates with the relative perihematoma edema volume (RPHEV) on days 3-4 after ICH. We undertook this study to directly examine the relationship between in vivo brain and hematoma iron content, measured by MRI, and RPHEV. METHODS We retrospectively reviewed prospectively collected clinical and laboratory data from 36 consecutive patients with acute spontaneous lobar ICH who had MRI performed within 2-4 days of ICH onset. We measured hematoma and edema volumes, and the signal intensity on T(2)-weighted images (T(2)SI), as an estimate of iron content, in the hematoma and contralateral globus pallidus (GP). We calculated the RPHEV and T(2)SI in the hematoma and GP, relative to T(2)SI in the frontal deep white matter which contains negligible iron, to estimate the hematoma and brain iron load. We used Spearman correlation coefficient to determine the association of relative T(2)SI of the hematoma and GP with RPHEV. RESULTS We found a significant inverse correlation between the relative T(2)SI in the hematoma (r = -0.75, p < 0.001) and to a lesser extent in the GP (r = -0.34, p = 0.04) and the RPHEV. CONCLUSIONS Our findings suggest that in vivo brain and hematoma iron content, as measured by MRI, is linked to perihematoma edema after ICH, and provide further support to existing preclinical evidence linking iron-mediated toxicity to delayed neuronal injury after ICH.
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Affiliation(s)
- Min Lou
- Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
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110
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Getting the iron out: phlebotomy for Alzheimer's disease? Med Hypotheses 2009; 72:504-9. [PMID: 19195795 DOI: 10.1016/j.mehy.2008.12.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 10/24/2008] [Accepted: 12/28/2008] [Indexed: 11/22/2022]
Abstract
This communication explores the temporal link between the age-associated increase in body iron stores and the age-related incidence of Alzheimer's disease (AD), the most prevalent cause of senile dementia. Body iron stores that increase with age could be pivotal to AD pathogenesis and progression. Increased stored iron is associated with common medical conditions such as diabetes and vascular disease that increase risk for development of AD. Increased stored iron could also promote oxidative stress/free radical damage in vulnerable neurons, a critical early change in AD. A ferrocentric model of AD described here forms the basis of a rational, easily testable experimental therapeutic approach for AD, which if successful, would be both widely applicable and inexpensive. Clinical studies have shown that calibrated phlebotomy is an effective way to reduce stored iron safely and predictably without causing anemia. We hypothesize that reducing stored iron by calibrated phlebotomy to avoid iron deficiency will improve cerebrovascular function, slow neurodegenerative change, and improve cognitive and behavioral functions in AD. The hypothesis is eminently testable as iron reduction therapy is useful for chronic diseases associated with iron excess such as nonalcoholic steatohepatitis (NASH), atherosclerosis, hereditary hemochromatosis and thalassemia. Testing this hypothesis could provide valuable insight into the causation of AD and suggest novel preventive and treatment strategies.
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111
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Rosen GD, Pung CJ, Owens CB, Caplow J, Kim H, Mozhui K, Lu L, Williams RW. Genetic modulation of striatal volume by loci on Chrs 6 and 17 in BXD recombinant inbred mice. GENES BRAIN AND BEHAVIOR 2009; 8:296-308. [PMID: 19191878 DOI: 10.1111/j.1601-183x.2009.00473.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Natural variation in the absolute and relative size of different parts of the human brain is substantial, with a range that often exceeds a factor of 2. Much of this variation is generated by the cumulative effects of sets of unknown gene variants that modulate the proliferation, growth and death of neurons and glial cells. Discovering and testing the functions of these genes should contribute significantly to our understanding of differences in brain development, behavior and disease susceptibility. We have exploited a large population of genetically well-characterized strains of mice (BXD recombinant inbred strains) to map gene variants that influence the volume of the dorsal striatum (caudate-putamen without nucleus accumbens). We used unbiased methods to estimate volumes bilaterally in a sex-balanced sample taken from the Mouse Brain Library (www.mbl.org). We generated a matched microarray data set to efficiently evaluate candidate genes (www.genenetwork.org). As in humans, volume of the striatum is highly heritable, with greater than twofold differences among strains. We mapped a locus that modulates striatal volume on chromosome (Chr) 6 at 88 +/- 5 Mb. We also uncovered an epistatic interaction between loci on Chr 6 and Chr 17 that modulates striatal volume. Using bioinformatic tools and the corresponding expression database, we have identified positional candidates in these quantitative trait locus intervals.
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Affiliation(s)
- G D Rosen
- Division of Behavioral Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
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113
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Snyder AM, Connor JR. Iron, the substantia nigra and related neurological disorders. Biochim Biophys Acta Gen Subj 2008; 1790:606-14. [PMID: 18778755 DOI: 10.1016/j.bbagen.2008.08.005] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 07/29/2008] [Accepted: 08/12/2008] [Indexed: 12/14/2022]
Abstract
BACKGROUND Iron status is higher in the substantia nigra than in other brain regions but can fluctuate as function of diet and genetics and disease. Of particular note is the compartmentalization of the iron-enrichment in this region; the pars reticulata contains higher levels of stainable iron as compared to the pars compacta. The latter area is where the dopaminergic neurons reside. How this compartmentalization impacts the interpretation of data that iron contributes to cell death as in Parkinson's disease or iron deficiency contributes to altered dopaminergic activity is unknown. Nonetheless, that iron can influence neuronal cell death and dopamine function is clear. METHODS The mechanisms by which iron may be managed in the substantia nigra, particularly in the neuromelanin cells where minimal levels of ferritin the iron storage protein have been detected are addressed. The current approaches to detect iron in the substantia nigra are also reviewed. In addition, the potential mechanisms by which iron enrichment may occur in the substantia nigra are explored. GENERAL SIGNIFICANCE This review attempts to provide a critical evaluation of the many avenues of exploration into the role of iron in one of the most iron-enriched and clinically investigated areas of the brain, the substantia nigra.
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Affiliation(s)
- Amanda M Snyder
- Department of Neurosurgery, Penn State University, M. S. Hershey Medical Center, Hershey, PA 17033, USA
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114
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Que EL, Domaille DW, Chang CJ. Metals in neurobiology: probing their chemistry and biology with molecular imaging. Chem Rev 2008; 108:1517-49. [PMID: 18426241 DOI: 10.1021/cr078203u] [Citation(s) in RCA: 1535] [Impact Index Per Article: 95.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Emily L Que
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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115
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Mehdiratta M, Kumar S, Hackney D, Schlaug G, Selim M. Association between serum ferritin level and perihematoma edema volume in patients with spontaneous intracerebral hemorrhage. Stroke 2008; 39:1165-70. [PMID: 18292378 DOI: 10.1161/strokeaha.107.501213] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Preclinical evidence indicates that iron plays a key role in mediating neuronal injury and edema formation after intracerebral hemorrhage (ICH). However, the clinical role of iron in patients with ICH has not been well studied. We undertook this exploratory study to investigate the association of serum ferritin, as an indicator of body iron load, with perihematoma edema after ICH. METHODS We retrospectively reviewed prospectively-collected clinical and laboratory data from 23 consecutive patients with acute spontaneous ICH who had a CT scan and serum ferritin checked on admission, and a follow-up CT scan 3 to 4 days afterward. We measured hematoma and edema volumes on admission and follow-up scans, and calculated the relative edema volume to correct for hematoma volume. We used Spearman correlation coefficient to determine the association of various variables with relative perihematoma edema volume. RESULTS Whereas the median hematoma volume increased by approximately 28% from baseline to day 3 to 4, the relative edema volume almost doubled during this time period. We observed a significant positive correlation between serum ferritin and relative perihematoma edema volume on day 3 to 4 (r=0.78; P=0.002), but not at baseline; and little correlation between the changes in hematoma volumes and corresponding relative edema volumes (r=0.14). There was a trend for a positive correlation between body temperature and relative edema volumes. CONCLUSIONS Our findings support the notion that delayed iron toxicity plays a role in causing brain injury and edema formation after ICH. These findings are preliminary and need to be further investigated in future studies.
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Affiliation(s)
- Manu Mehdiratta
- Department of Neurology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Mass. 02215, USA
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116
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Chua TC, Wen W, Slavin MJ, Sachdev PS. Diffusion tensor imaging in mild cognitive impairment and Alzheimerʼs disease: a review. Curr Opin Neurol 2008; 21:83-92. [DOI: 10.1097/wco.0b013e3282f4594b] [Citation(s) in RCA: 213] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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117
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Ge Y, Jensen JH, Lu H, Helpern JA, Miles L, Inglese M, Babb JS, Herbert J, Grossman RI. Quantitative assessment of iron accumulation in the deep gray matter of multiple sclerosis by magnetic field correlation imaging. AJNR Am J Neuroradiol 2007; 28:1639-44. [PMID: 17893225 PMCID: PMC8134218 DOI: 10.3174/ajnr.a0646] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Deposition of iron has been recognized recently as an important factor of pathophysiologic change including neurodegenerative processes in multiple sclerosis (MS). We propose that there is an excess accumulation of iron in the deep gray matter in patients with MS that can be measured with a newly developed quantitative MR technique--magnetic field correlation (MFC) imaging. MATERIALS AND METHODS With a 3T MR system, we studied 17 patients with relapsing-remitting MS and 14 age-matched healthy control subjects. We acquired MFC imaging using an asymmetric single-shot echo-planar imaging sequence. Regions of interest were selected in both deep gray matter and white matter regions, and the mean MFC values were compared between patients and controls. We also correlated the MFC data with lesion load and neuropsychologic tests in the patients. RESULTS MFC measured in the deep gray matter in patients with MS was significantly higher than that in the healthy controls (P < or = .03), with an average increase of 24% in the globus pallidus, 39.5% in the putamen, and 30.6% in the thalamus. The increased iron deposition measured with MFC in the deep gray matter in the patients correlated positively with the total number of MS lesions (thalamus: r = 0.61, P = .01; globus pallidus: r = 0.52, P = .02). A moderate but significant correlation between the MFC value in the deep gray matter and the neuropsychologic tests was also found. CONCLUSION Quantitative measurements of iron content with MFC demonstrate increased accumulation of iron in the deep gray matter in patients with MS, which may be associated with the disrupted iron outflow pathway by lesions. Such abnormal accumulation of iron may contribute to neuropsychologic impairment and have implications for neurodegenerative processes in MS.
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Affiliation(s)
- Y Ge
- Center for Biomedical Imaging, Department of Radiology, New York University Medical Center, New York, NY 10016, USA.
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118
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Kaushik P, Gorin F, Vali S. Dynamics of tyrosine hydroxylase mediated regulation of dopamine synthesis. J Comput Neurosci 2007; 22:147-60. [PMID: 17053993 DOI: 10.1007/s10827-006-0004-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Revised: 08/02/2006] [Accepted: 08/02/2006] [Indexed: 02/02/2023]
Abstract
Tyrosine hydroxylase's catalysis of tyrosine to dihydroxyphenylalanine (DOPA) is the highly regulated, rate-limiting step catalyzing the synthesis of the catecholamine neurotransmitter dopamine. Phosphorylation, cofactor-mediated regulation, and the cell's redox status, have been shown to regulate the enzyme's activity. This paper incorporates these regulatory mechanisms into an integrated dynamic model that is capable of demonstrating relative rates of dopamine synthesis under various physiological conditions. Most of the kinetic equations and substrate parameters used in the model correspond with published experimental data, while a few which were not available in literature have been optimized based on explicit assumptions. This kinetic pathway model permits a comparison of the relative regulatory contributions made by variations in substrate, phosphorylation, and redox status on enzymatic activity and permits predictions of potential disease states. For example, the model correctly predicts the recent observation that individuals with haemochromatosis and having excessive iron accumulation are at increased risk for acquiring Parkinsonism, a defect in neuronal dopamine synthesis (Bartzokis et al., 2004; Costello et al., 2004). Alpha synuclein mediated regulation of tyrosine hydroxylase has also been incorporated in the model, allowing an insight into the overexpression and aggregation of alpha synuclein in Parkinson's disease.
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Affiliation(s)
- Poorvi Kaushik
- Cellworks Group Inc., 13962 Pierce Road, Saratoga, CA 95070, USA
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119
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Ke Y, Qian ZM. Brain iron metabolism: neurobiology and neurochemistry. Prog Neurobiol 2007; 83:149-73. [PMID: 17870230 DOI: 10.1016/j.pneurobio.2007.07.009] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 04/10/2007] [Accepted: 07/26/2007] [Indexed: 01/09/2023]
Abstract
New findings obtained during the past years, especially the discovery of mutations in the genes associated with brain iron metabolism, have provided key insights into the homeostatic mechanisms of brain iron metabolism and the pathological mechanisms responsible for neurodegenerative diseases. The accumulated evidence demonstrates that misregulation in brain iron metabolism is one of the initial causes for neuronal death in some neurodegenerative disorders. The errors in brain iron metabolism found in these disorders have a multifactorial pathogenesis, including genetic and nongenetic factors. The disturbances of iron metabolism might occur at multiple levels, including iron uptake and release, storage, intracellular metabolism and regulation. It is the increased brain iron that triggers a cascade of deleterious events, leading to neuronal death in these diseases. In the article, the recent advances in studies on neurochemistry and neuropathophysiology of brain iron metabolism were reviewed.
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Affiliation(s)
- Ya Ke
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, NT, Hong Kong
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120
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Simmons DA, Casale M, Alcon B, Pham N, Narayan N, Lynch G. Ferritin accumulation in dystrophic microglia is an early event in the development of Huntington's disease. Glia 2007; 55:1074-84. [PMID: 17551926 DOI: 10.1002/glia.20526] [Citation(s) in RCA: 197] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Huntington's Disease (HD) is characterized primarily by neuropathological changes in the striatum, including loss of medium-spiny neurons, nuclear inclusions of the huntingtin protein, gliosis, and abnormally high iron levels. Information about how these conditions interact, or about the temporal order in which they appear, is lacking. This study investigated if, and when, iron-related changes occur in the R6/2 transgenic mouse model of HD and compared the results with those from HD patients. Relative to wild-type mice, R6/2 mice had increased immunostaining for ferritin, an iron storage protein, in the striatum beginning at 2-4 weeks postnatal and in cortex and hippocampus starting at 5-7 weeks. The ferritin staining was found primarily in microglia, and became more pronounced as the mice matured. Ferritin-labeled microglia in R6/2 mice appeared dystrophic in that they had thick, twisted processes with cytoplasmic breaks; some of these cells also contained the mutant huntingtin protein. Brains from HD patients (Vonsattel grades 0-4) also had increased numbers of ferritin-containing microglia, some of which were dystrophic. The cells were positive for Perl's stain, indicating that they contained abnormally high levels of iron. These results provide the first evidence that perturbations to iron metabolism in HD are predominately associated with microglia and occur early enough to be important contributors to HD progression.
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Affiliation(s)
- Danielle A Simmons
- Department of Psychiatry and Human Behavior, University of California, Irvine, California 92697-4292, USA.
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121
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Stankiewicz J, Panter SS, Neema M, Arora A, Batt CE, Bakshi R. Iron in chronic brain disorders: imaging and neurotherapeutic implications. Neurotherapeutics 2007; 4:371-86. [PMID: 17599703 PMCID: PMC1963417 DOI: 10.1016/j.nurt.2007.05.006] [Citation(s) in RCA: 214] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Iron is important for brain oxygen transport, electron transfer, neurotransmitter synthesis, and myelin production. Though iron deposition has been observed in the brain with normal aging, increased iron has also been shown in many chronic neurological disorders including Alzheimer's disease, Parkinson's disease, and multiple sclerosis. In vitro studies have demonstrated that excessive iron can lead to free radical production, which can promote neurotoxicity. However, the link between observed iron deposition and pathological processes underlying various diseases of the brain is not well understood. It is not known whether excessive in vivo iron directly contributes to tissue damage or is solely an epiphenomenon. In this article, we focus on the imaging of brain iron and the underlying physiology and metabolism relating to iron deposition. We conclude with a discussion of the potential implications of iron-related toxicity to neurotherapeutic development.
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Affiliation(s)
- James Stankiewicz
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, 02115 Boston, Massachusetts
| | - S. Scott Panter
- Department of Neurological Surgery, Veteran’s Administration Hospital, University of California, 94121 San Francisco, California
| | - Mohit Neema
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, 02115 Boston, Massachusetts
| | - Ashish Arora
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, 02115 Boston, Massachusetts
| | - Courtney E. Batt
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, 02115 Boston, Massachusetts
| | - Rohit Bakshi
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, 02115 Boston, Massachusetts
- Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, 02115 Boston, Massachusetts
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122
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Mandel S, Amit T, Bar-Am O, Youdim MBH. Iron dysregulation in Alzheimer's disease: multimodal brain permeable iron chelating drugs, possessing neuroprotective-neurorescue and amyloid precursor protein-processing regulatory activities as therapeutic agents. Prog Neurobiol 2007; 82:348-60. [PMID: 17659826 DOI: 10.1016/j.pneurobio.2007.06.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 04/11/2007] [Accepted: 06/11/2007] [Indexed: 10/23/2022]
Abstract
Considering the multi-etiological character of Alzheimer's disease (AD), the current pharmacological approaches using drugs oriented towards a single molecular target possess limited ability to modify the course of the disease and thus, offer a partial benefit to the patient. In line with this concept, novel strategies include the use of a cocktail of several drugs and/or the development of a single molecule, possessing two or more active neuroprotective-neurorescue moieties that simultaneously manipulate multiple targets involved in AD pathology. A consistent observation in AD is a dysregulation of metal ions (Fe(2+), Cu(2+) and Zn(2+)) homeostasis and consequential induction of oxidative stress, associated with beta-amyloid aggregation and neurite plaque formation. In particular, iron has been demonstrated to modulate the Alzheimer's amyloid precursor holo-protein expression by a pathway similar to that of ferritin L-and H-mRNA translation through iron-responsive elements in their 5'UTRs. This review will discuss two separate scenarios concerning multiple therapy targets in AD, sharing in common the implementation of iron chelation activity: (i) novel multimodal brain-permeable iron chelating drugs, possessing neuroprotective-neurorescue and amyloid precursor protein-processing regulatory activities; (ii) natural plant polyphenols (flavonoids), such as green tea epigallocatechin gallate (EGCG) and curcumin, reported to have access to the brain and to possess multifunctional activities, such as metal chelation-radical scavenging, anti-inflammation and neuroprotection.
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Affiliation(s)
- Silvia Mandel
- Eve Topf and USA NPF Centers of Excellence, Technion-Faculty of Medicine, Department of Pharmacology, Israel
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Bartzokis G, Lu PH, Tishler TA, Fong SM, Oluwadara B, Finn JP, Huang D, Bordelon Y, Mintz J, Perlman S. Myelin breakdown and iron changes in Huntington's disease: pathogenesis and treatment implications. Neurochem Res 2007; 32:1655-64. [PMID: 17484051 DOI: 10.1007/s11064-007-9352-7] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Accepted: 04/05/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND Postmortem and in vivo imaging data support the hypothesis that premature myelin breakdown and subsequent homeostatic remyelination attempts with increased oligodendrocyte and iron levels may contribute to Huntington's Disease (HD) pathogenesis and the symmetrical progress of neuronal loss from earlier-myelinating striatum to later-myelinating regions. A unique combination of in vivo tissue integrity and iron level assessments was used to examine the hypothesis. METHODS A method that uses two Magnetic resonance imaging (MRI) instruments operating at different field-strengths was used to quantify the iron content of ferritin molecules (ferritin iron) as well as tissue integrity in eight regions in 11 HD and a matched group of 27 healthy control subjects. Three white matter regions were selected based on their myelination pattern (early to later-myelinating) and fiber composition. These were frontal lobe white matter (Fwm) and splenium and genu of the corpus callosum (Swm and Gwm). In addition, gray matter structures were also chosen based on their myelination pattern and fiber composition. Three striatum structures were assessed [caudate, putamen, and globus pallidus (C, P, and G)] as well as two comparison gray matter regions that myelinate later in development and are relatively spared in HD [Hippocampus (Hipp) and Thalamus (Th)]. RESULTS Compared to healthy controls, HD ferritin iron levels were significantly increased in striatum C, P, and G, decreased in Fwm and Gwm, and were unchanged in Hipp, Th, and Swm. Loss of tissue integrity was observed in C, P, Fwm, and especially Swm but not Hipp, Th, G, or Gwm. This pattern of findings was largely preserved when a small subset of HD subjects early in the disease process was examined. CONCLUSIONS The data suggest early in the HD process, myelin breakdown and changes in ferritin iron distribution underlie the pattern of regional toxicity observed in HD. Prospective studies are needed to verify myelin breakdown and increased iron levels are causal factors in HD pathogenesis. Tracking the effects of novel interventions that reduce myelin breakdown and iron accumulation in preclinical stages of HD could hasten the development of preventive treatments.
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Affiliation(s)
- George Bartzokis
- Department of Neurology, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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124
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Koorts AM, Viljoen M. Ferritin and ferritin isoforms II: protection against uncontrolled cellular proliferation, oxidative damage and inflammatory processes. Arch Physiol Biochem 2007; 113:55-64. [PMID: 17558604 DOI: 10.1080/13813450701422575] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Ferritin is a major iron storage protein involved in the regulation of iron availability. Each ferritin molecule comprises 24 subunits. Various combinations of H-subunits and L-subunits make up the 24-subunit protein structure and these ferritin isoforms differ in their H-subunit to L-subunit ratio, as well as in their metabolic properties. Ferritin is an acute-phase protein and its expression is up-regulated in conditions such as uncontrolled cellular proliferation, in any condition marked by excessive production of toxic oxygen radicals, and by infectious and inflammatory processes. Under such conditions ferritin up-regulation is predominantly stimulated by increased reactive oxygen radical production and by cytokines. The major function of ferritin in these conditions is to reduce the bio-availability of iron in order to stem uncontrolled cellular proliferation and excessive production of reactive oxygen radicals. Ferritin is not, however, indiscriminately up-regulated in these conditions as a marked shift towards a predominance in H-subunit rich ferritins occurs. Preliminary indications are that, while the L-subunit primarily fulfils the conventional iron storage role, the H-subunit functions primarily as rapid regulator of iron availability, and perhaps indirectly as regulator of other cellular processes. It is suggested that the optimum differential expression of the two subunits differ for different cells and under different conditions and that the expression of appropriate isoferritins offers protection against uncontrolled cellular proliferation, oxidative stress and against side effects of infectious and inflammatory conditions.
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Affiliation(s)
- A M Koorts
- Department of Physiology, School of Medicine, University of Pretoria, Pretoria, South Africa.
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125
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Brem F, Hirt AM, Winklhofer M, Frei K, Yonekawa Y, Wieser HG, Dobson J. Magnetic iron compounds in the human brain: a comparison of tumour and hippocampal tissue. J R Soc Interface 2007; 3:833-41. [PMID: 17015303 PMCID: PMC1885366 DOI: 10.1098/rsif.2006.0133] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Iron is a central element in the metabolism of normal and malignant cells. Abnormalities in iron and ferritin expression have been observed in many types of cancer. Interest in characterizing iron compounds in the human brain has increased due to advances in determining a relationship between excess iron accumulation and neurological and neurodegenerative diseases. In this work, four different magnetic methods have been employed to characterize the iron phases and magnetic properties of brain tumour (meningiomas) tissues and non-tumour hippocampal tissues. Four main magnetic components can be distinguished: the diamagnetic matrix, nearly paramagnetic blood, antiferromagnetic ferrihydrite cores of ferritin and ferrimagnetic magnetite and/or maghemite. For the first time, open hysteresis loops have been observed on human brain tissue at room temperature. The hysteresis properties indicate the presence of magnetite and/or maghemite particles that exhibit stable single-domain (SD) behaviour at room temperature. A significantly higher concentration of magnetically ordered magnetite and/or maghemite and a higher estimated concentration of heme iron was found in the meningioma samples. First-order reversal curve diagrams on meningioma tissue further show that the stable SD particles are magnetostatically interacting, implying high-local concentrations (clustering) of these particles in brain tumours. These findings suggest that brain tumour tissue contains an elevated amount of remanent iron oxide phases.
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Affiliation(s)
- Franziska Brem
- Institute of GeophysicsETH-Hönggerberg, 8093 Zurich, Switzerland
| | - Ann M Hirt
- Institute of GeophysicsETH-Hönggerberg, 8093 Zurich, Switzerland
- Author for correspondence ()
| | - Michael Winklhofer
- Department of Earth and Environmental Science, University of Munich80333 München, Germany
| | - Karl Frei
- Department of Neurosurgery, University Hospital Zurich8091 Zurich, Switzerland
| | - Yasuhiro Yonekawa
- Department of Neurosurgery, University Hospital Zurich8091 Zurich, Switzerland
| | | | - Jon Dobson
- Institute for Science & Technology in Medicine, Keele UniversityStoke-on-Trent ST4 7QB, UK
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126
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127
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Friedman A, Galazka-Friedman J, Bauminger ER. Iron as a trigger of neurodegeneration in Parkinson's disease. HANDBOOK OF CLINICAL NEUROLOGY 2007; 83:493-505. [PMID: 18808930 DOI: 10.1016/s0072-9752(07)83023-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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128
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Péran P, Hagberg G, Luccichenti G, Cherubini A, Brainovich V, Celsis P, Caltagirone C, Sabatini U. Voxel-based analysis of R2* maps in the healthy human brain. J Magn Reson Imaging 2007; 26:1413-20. [DOI: 10.1002/jmri.21204] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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129
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Early detection of Parkinson's disease. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s0072-9752(07)83021-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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130
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Mani V, Briley-Saebo KC, Hyafil F, Fayad ZA. Feasibility of in vivo identification of endogenous ferritin with positive contrast MRI in rabbit carotid crush injury using GRASP. Magn Reson Med 2006; 56:1096-106. [PMID: 17036302 DOI: 10.1002/mrm.21060] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In vivo markers that allow for detection of ferritin within atheromatous plaque may be useful for identifying iron-catalyzed hydroxyl-radical formation and subsequent lipid peroxidation. Recently, a positive contrast MR technique--GRadient echo Acquisition for Superparamagnetic particles/suscePtibility (GRASP)--was used to identify the presence of magnetic entities in phantom models. The aim of the current study was to determine the feasibility of using GRASP in conjunction with conventional T(2) (*)-weighted (T(2) (*)W) gradient-echo (GRE) sequences for identifying ferritin/hemosiderin deposition using in vitro and in vivo models of thrombus. In vitro thrombi were prepared by incubating blood with ferritin. MRI was performed using conventional GRE sequences and GRASP. The results indicate that GRASP was able to verify ferritin deposition in in vitro thrombi. In vivo thrombi were created using a crush injury model in rabbits. The signal enhancement obtained using conventional GRE sequences and GRASP was compared with the location of iron deposition by histology. In all of the animals the GRASP signal correlated with signal loss by conventional GRE, and ferritin/hemosiderin deposition by histology. GRASP sequences in combination with conventional GRE sequences may be used to detect the presence of ferritin deposition in in vitro thrombi and in vivo crush-injured rabbit carotid arteries.
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Affiliation(s)
- Venkatesh Mani
- Imaging Science Laboratories, Mount Sinai School of Medicine, New York, New York 10029-6574, USA
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131
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Abstract
Brain iron uptake is regulated by the expression of transferrin receptor 1 in endothelial cells of the blood-brain barrier. Transferrin-bound iron in the systemic circulation is endocytosed by brain endothelial cells, and elemental iron is released to brain interstitial fluid, likely by the iron exporter, ferroportin. Transferrin synthesized by oligodendrocytes in the brain binds much of the iron that traverses the blood-brain barrier after oxidation of the iron, most likely by a glycophosphosinositide-linked ceruloplasmin found in astrocytic foot processes that ensheathe brain endothelial cells. Neurons acquire iron from diferric transferrin, but it is less clear how glial cells acquire iron. In aging mammals, iron accumulates in the basal ganglia, and iron accumulation is believed to contribute to neurodegenerative diseases, including Parkinson and Alzheimer disease. Here we consider the possibility that iron accumulations, which are often thought to facilitate free radical generation and oxidative damage, may contain insoluble iron that is unavailable for cellular use, and the pathology associated with iron accumulations may result from functional iron deficiency in some diseases.
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Affiliation(s)
- Tracey A Rouault
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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132
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Kaur D, Rajagopalan S, Chinta S, Kumar J, Di Monte D, Cherny RA, Andersen JK. Chronic ferritin expression within murine dopaminergic midbrain neurons results in a progressive age-related neurodegeneration. Brain Res 2006; 1140:188-94. [PMID: 16631136 DOI: 10.1016/j.brainres.2006.03.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2006] [Revised: 02/27/2006] [Accepted: 03/07/2006] [Indexed: 11/29/2022]
Abstract
Ferritin elevation has been reported by some laboratories to occur within the substantia nigra (SN), the area of the brain affected in Parkinson's disease (PD), but whether such an increase could be causatively involved in neurodegeneration associated with the disorder is unknown. Here, we report that chronic ferritin elevation in midbrain dopamine-containing neurons results in a progressive age-related neurodegeneration of these cells. This provides strong evidence that chronic ferritin overload could be directly involved in age-related neurodegeneration such as occurs in Parkinson's and other related diseases.
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Affiliation(s)
- Deepinder Kaur
- Buck Institute for Research in Aging, Novato, CA 94945, USA
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133
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Brass SD, Chen NK, Mulkern RV, Bakshi R. Magnetic resonance imaging of iron deposition in neurological disorders. Top Magn Reson Imaging 2006; 17:31-40. [PMID: 17179895 DOI: 10.1097/01.rmr.0000245459.82782.e4] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Deposition of iron in the brain is proposed to play a role in the pathophysiology of the normal aging process and neurodegenerative diseases. Whereas iron is required for normal neuronal metabolism, excessive levels can contribute to the formation of free radicals, leading to lipid peroxidation and neurotoxicity. Magnetic resonance imaging (MRI) is a powerful tool to detect excessive iron in the brain and longitudinally monitor changes in iron levels. Iron deposition is associated with a reduction in the T2 relaxation time, leading to hypointensity on spin-echo and gradient-echo T2-weighted images. The MRI changes associated with iron deposition have been observed both in normal aging and in various chronic neurological diseases, including multiple sclerosis, Alzheimer disease, and Parkinson disease. Magnetic resonance imaging metrics providing information about iron concentrations include R2, R2', and R2*. The purpose of this review is to discuss the role of iron and its detection by MRI in various neurological disorders. We will review the basic biochemical properties of iron and its influence on MRI signal. We will also summarize the sensitivity and specificity of MRI techniques in detecting iron. The MRI and pathological findings pertaining to brain iron will be reviewed with respect to normal aging and a variety of neurological disorders. Finally, the biochemistry and pathophysiology surrounding iron, oxidative stress, free radicals, and lipid peroxidation in the brain will be discussed, including therapeutic implications. The potential role of iron deposition and its assessment by MRI provides exciting potential applications to the diagnosis, longitudinal monitoring, and therapeutic development for disorders of the brain.
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Affiliation(s)
- Steven D Brass
- Center for Neurological Imaging, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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134
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Sehgal V, Delproposto Z, Haacke EM, Tong KA, Wycliffe N, Kido DK, Xu Y, Neelavalli J, Haddar D, Reichenbach JR. Clinical applications of neuroimaging with susceptibility-weighted imaging. J Magn Reson Imaging 2006; 22:439-50. [PMID: 16163700 DOI: 10.1002/jmri.20404] [Citation(s) in RCA: 360] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Susceptibility-weighted imaging (SWI) consists of using both magnitude and phase images from a high-resolution, three-dimensional, fully velocity compensated gradient-echo sequence. Postprocessing is applied to the magnitude image by means of a phase mask to increase the conspicuity of the veins and other sources of susceptibility effects. This article gives a background of the SWI technique and describes its role in clinical neuroimaging. SWI is currently being tested in a number of centers worldwide as an emerging technique to improve the diagnosis of neurological trauma, brain neoplasms, and neurovascular diseases because of its ability to reveal vascular abnormalities and microbleeds.
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Affiliation(s)
- Vivek Sehgal
- Department of Radiology, Harper University Hospital, Detroit, Michigan, USA
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135
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Quintana C, Bellefqih S, Laval JY, Guerquin-Kern JL, Wu TD, Avila J, Ferrer I, Arranz R, Patiño C. Study of the localization of iron, ferritin, and hemosiderin in Alzheimer’s disease hippocampus by analytical microscopy at the subcellular level. J Struct Biol 2006; 153:42-54. [PMID: 16364657 DOI: 10.1016/j.jsb.2005.11.001] [Citation(s) in RCA: 208] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Revised: 09/19/2005] [Accepted: 11/03/2005] [Indexed: 10/25/2022]
Abstract
Previous studies of the structure of core nanocrystals of ferritin (Ft) in the brains of patients with Alzheimer's disease (AD) have shown differences in the mineral compound in comparison with physiological Ft. Both Ft cores have a polyphasic composition but whereas the major phase in physiological Ft is hexagonal ferric iron oxide (ferrihydrite), the major phases in brain AD Ft are two cubic mixed ferric-ferrous iron oxides (magnetite and wüstite). One of these (wüstite) is similar to what is detected in hemosiderin (Hm) cores in primary hemochromatosis (Quintana, C., Cowley, J.M, Marhic, C., 2004. Electron nanodiffraction and high resolution electron microscopy studies of the structure and composition of physiological and pathological ferritin. J. Struct. Biol. 147, 166-178). We have studied, herein, the distribution of iron, Ft, and Hm in sections of AD hippocampus using analytical microscopy. Iron present in Ft cores was directly mapped in a nanoSIMS microscope and the iron distribution has been correlated with the constituent elements N, P, and S. Ft and Hm cores were visualized at an ultrastructural level in an analytical transmission electron microscope. In senile plaques, Ft was observed in the coronal region associated with a non-beta-amyloid component and in the periphery of plaques, together with Hm, in sulfur-rich dense bodies of dystrophic neurites. Hm was also found in lysosomes and siderosomes of glial cells. Ft was observed in the cytoplasm and nucleus of oligodendrocytes. Ft was particularly abundant in myelinated axons in association with oligodendrocyte processes. These findings provide new arguments to support the hypothesis of a dysfunction of Ft (with eventual degradation to Hm) in AD resulting in an increase of toxic brain ferrous ions that may contribute to the production of free radicals that induce both cellular oxidative stress and aged-related myelin breakdown associated with cognitive decline and AD (Bartzokis, G., 2004. Age-related myelin breakdown: a developmental model of cognitive decline and Alzheimer's disease. Neurobiol. Aging 25, 5-18).
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136
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Liu G, Garrett MR, Men P, Zhu X, Perry G, Smith MA. Nanoparticle and other metal chelation therapeutics in Alzheimer disease. Biochim Biophys Acta Mol Basis Dis 2005; 1741:246-52. [PMID: 16051470 DOI: 10.1016/j.bbadis.2005.06.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 06/21/2005] [Accepted: 06/29/2005] [Indexed: 11/16/2022]
Abstract
Current therapies for Alzheimer disease (AD) such as the anticholinesterase inhibitors and the latest NMDA receptor inhibitor, Namenda, provide moderate symptomatic delay at various stages of disease, but do not arrest disease progression or supply meaningful remission. As such, new approaches to disease management are urgently needed. Although the etiology of AD is largely unknown, oxidative damage mediated by metals is likely a significant contributor since metals such as iron, aluminum, zinc, and copper are dysregulated and/or increased in AD brain tissue and create a pro-oxidative environment. This role of metal ion-induced free radical formation in AD makes chelation therapy an attractive means of dampening the oxidative stress burden in neurons. The chelator desferioxamine, FDA approved for iron overload, has shown some benefit in AD, but like many chelators, it has a host of adverse effects and substantial obstacles for tissue-specific targeting. Other chelators are under development and have shown various strengths and weaknesses. In this review, we propose a novel system of chelation therapy through the use of nanoparticles. Nanoparticles conjugated to chelators show a unique ability to cross the blood-brain barrier (BBB), chelate metals, and exit through the BBB with their corresponding complexed metal ions. This method may prove to be a safe and effective means of reducing the metal load in neural tissue thus staving off the harmful effects of oxidative damage and its sequelae.
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Affiliation(s)
- Gang Liu
- Department of Radiology, University of Utah, Salt Lake City, UT 84102, USA
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137
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Collingwood JF, Mikhaylova A, Davidson MR, Batich C, Streit WJ, Eskin T, Terry J, Barrea R, Underhill RS, Dobson J. High-resolution x-ray absorption spectroscopy studies of metal compounds in neurodegenerative brain tissue. ACTA ACUST UNITED AC 2005. [DOI: 10.1088/1742-6596/17/1/009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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138
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Tjoa CW, Benedict RHB, Weinstock-Guttman B, Fabiano AJ, Bakshi R. MRI T2 hypointensity of the dentate nucleus is related to ambulatory impairment in multiple sclerosis. J Neurol Sci 2005; 234:17-24. [PMID: 15993137 DOI: 10.1016/j.jns.2005.02.009] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2004] [Revised: 01/24/2005] [Accepted: 02/18/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES MRI T2 hypointensity in multiple sclerosis (MS) gray matter, suggesting iron deposition, is associated with physical disability, disease course, lesion load, and brain atrophy. Ambulatory dysfunction limits quality of life; however correlation with conventional MRI remains poor. METHODS Normalized intensity on T2-weighted images was obtained in the basal ganglia, thalamus, red nucleus, and dentate nucleus in 47 MS patients and 15 healthy controls. Brain T1-hypointense and FLAIR-hyperintense lesion volume, third ventricle width, brain parenchymal fraction and timed 25 foot walk (T25FW) were measured in the MS group. RESULTS T2 hypointensity was present throughout gray matter in MS vs. controls (all p<0.01). Dentate T2 hypointensity was the only MRI variable significantly correlated with T25FW (Pearson r=-0.355, p=0.007) and was also the best MRI correlate of physical disability (EDSS) score in regression modeling (r=-0.463, R(2)=0.223, p=0.004). CONCLUSIONS T2 hypointensity is present in subcortical gray matter nuclei in patients with MS vs. normal controls. Dentate nucleus T2 hypointensity is independently related to ambulatory impairment and disability, accounting for more variance than conventional lesion and atrophy measures. This study adds more weight to the notion that T2 hypointensity is a clinically relevant marker of tissue damage in MS.
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Affiliation(s)
- C W Tjoa
- Department of Neurology, University at Buffalo, State University of New York, Buffalo, NY, USA
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139
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Abstract
The understanding of aging in our society with steadily increasing life expectancy is an important challenge in medical science since socioeconomic pressure increases in parallel. Magnetic resonance imaging is a most useful tool to explore age related changes in the central nervous system especially in the brain. This article will focus on current knowledge and importance of such changes. Special attention will paid to white matter hyperintensities in terms of occurrence and progression and cerebral microbleeds in terms of their association to various diseases and their possible influence on thrombolytic therapy. Furthermore the meaning of darkening of the basal ganglia will be discussed and, in more general terms, the occurrence of virchow robin spaces and changes in cerebral metabolites assessable by proton magnetic resonance spectroscopy.
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Affiliation(s)
- Peter Kapeller
- Department of Neurology, Medical University Graz, Graz, Austria.
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140
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Huang E, Ong WY. Distribution of ferritin in the rat hippocampus after kainate-induced neuronal injury. Exp Brain Res 2004; 161:502-11. [PMID: 15747160 DOI: 10.1007/s00221-004-2110-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2004] [Accepted: 08/28/2004] [Indexed: 11/25/2022]
Abstract
A gradual increase in iron occurs in the lesioned hippocampus after neuronal injury induced by the excitotoxin kainate, and the present study was carried out to investigate whether this increase in iron might be associated with changes in expression of the iron binding protein, ferritin. An increase in ferritin immunoreactivity was observed in glial cells of the hippocampus, as early as three days after intracerebroventricular injections of kainate. The number of ferritin positive cells peaked four weeks after the kainate injection, and decreased eight and twelve weeks after injection. They were found to be mostly microglia and oligodendrocytes by double immunofluorescence labeling with glial markers. A number of ferritin-labeled endothelial cells were also observed via electron microscopy. The decline in ferritin immunoreactivity four weeks after the injection of kainate is accompanied by an increase in the number of ferric and ferrous iron positive cells in the lesioned tissue. A substantial non-overlap between ferritin and iron-containing cells was observed. In particular, spherical ferric or ferrous iron-laden cells in the degenerating hippocampus were unlabeled for ferritin for long time periods after the kainate injection. An increase in iron, together with a reduced expression of iron binding proteins such as ferritin at long time intervals after kainate lesions, could result in a relative decrease in ferritin-induced ferroxidase activity and the presence of some of the iron in the ferrous form. It is postulated that this may contribute to chronic neuronal injury, following acute kainate-induced neurodegeneration.
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Affiliation(s)
- En Huang
- Department of Anatomy, National University of Singapore, 119260 Singapore
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