Leaching of Trace Elements from Biological Tissue by Formalin Fixation

Gellein, Kristin; Flaten, Trond Peder; Erikson, Keith M.; Aschner, Michael; Syversen, Tore

doi:10.1007/s12011-007-8051-1

Cited by 74 publications

(72 citation statements)

References 10 publications

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“…It has been reported that formalin leaches out iron from the brain and other tissues in a time-dependent manner (Smith et al, 1997). An experimental approach using atomic absorption spectroscopy revealed that a formalin fixation lasting 4 years leads to an average brain iron reduction of 43% (Schrag et al, 2010), although some studies have suggested a smaller effects (Chuaanusorn et al, 1997;Gellein et al, 2008). At the time of imaging, the brain of Case MS-1 had been stored in formalin for 3 years, compared with 3 months for Case MS-2 and 2 months for the non-multiple sclerosis donor.…”

Section: Subpial Iron Accumulation Was Present In Case Ms-1mentioning

confidence: 99%

Tracking iron in multiple sclerosis: a combined imaging and histopathological study at 7 Tesla

Bagnato

Hametner²,

Yao³

et al. 2011

Brain

311

346

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Previous authors have shown that the transverse relaxivity R 2 * and frequency shifts that characterize gradient echo signal decay in magnetic resonance imaging are closely associated with the distribution of iron and myelin in the brain's white matter. In multiple sclerosis, iron accumulation in brain tissue may reflect a multiplicity of pathological processes. Hence, iron may have the unique potential to serve as an in vivo magnetic resonance imaging tracer of disease pathology. To investigate the ability of iron in tracking multiple sclerosis-induced pathology by magnetic resonance imaging, we performed qualitative histopathological analysis of white matter lesions and normal-appearing white matter regions with variable appearance on gradient echo magnetic resonance imaging at 7 Tesla. The samples used for this study derive from two patients with multiple sclerosis and one non-multiple sclerosis donor. Magnetic resonance images were acquired using a whole body 7 Tesla magnetic resonance imaging scanner equipped with a 24-channel receive-only array designed for tissue imaging. A 3D multi-gradient echo sequence was obtained and quantitative R 2 * and phase maps were reconstructed. Immunohistochemical stainings for myelin and oligodendrocytes, microglia and macrophages, ferritin and ferritin light polypeptide were performed on 3-to 5-mm thick paraffin sections. Iron was detected with Perl's staining and 3,3 0 -diaminobenzidine-tetrahydrochloride enhanced Turnbull blue staining.In multiple sclerosis tissue, iron presence invariably matched with an increase in R 2 *. Conversely, R 2 * increase was not always associated with the presence of iron on histochemical staining. We interpret this finding as the effect of embedding, sectioning and staining procedures. These processes likely affected the histopathological analysis results but not the magnetic resonance imaging that was obtained before tissue manipulations. Several cellular sources of iron were identified. These sources included oligodendrocytes in normal-appearing white matter and activated macrophages/microglia at the edges of white matter lesions. Additionally, in white matter lesions, iron precipitation in aggregates typical of microbleeds was shown by the Perl's staining. Our combined imaging and pathological study shows that multi-gradient echo magnetic resonance imaging is a sensitive technique for the identification of iron in the brain tissue of patients with multiple sclerosis. However, magnetic resonance doi:10.1093/brain/awr278 imaging-identified iron does not necessarily reflect pathology and may also be seen in apparently normal tissue. Iron identification by multi-gradient echo magnetic resonance imaging in diseased tissues can shed light on the pathological processes when coupled with topographical information and patient disease history.

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Section: Subpial Iron Accumulation Was Present In Case Ms-1mentioning

confidence: 99%

Tracking iron in multiple sclerosis: a combined imaging and histopathological study at 7 Tesla

Bagnato

Hametner²,

Yao³

et al. 2011

Brain

311

346

View full text Add to dashboard Cite

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“…The degree of leaching is time dependent and very different for different elements. A study ( 37 ) that used highspatial-resolution inductively coupled plasma mass spectrometry to measure 19 metal elements in the human brain showed that there was moderate iron leaching after long-term storage (about 20 years), compared with other metal showed that in this area (high iron, normal myelin), both phase and R2* had a prominent contrast (high R2* values and negative frequency shift). However, in the inner part of the lesion, where iron and myelin were both preserved, an increased R2* but little frequency shift was observed.…”

Section: Neuroradiology: High-field-strength Mr Imaging Of Chronic Mumentioning

confidence: 99%

Chronic Multiple Sclerosis Lesions: Characterization with High-Field-Strength MR Imaging

Yao¹,

Bagnato²,

Matsuura³

et al. 2012

Radiology

120

124

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Purpose:To elucidate the mechanism of magnetic resonance (MR) imaging contrast in multiple sclerosis (MS) lesion appearance by using susceptibility-weighted imaging and to assess with histologic correlation the role of iron and myelin in generating this MR imaging contrast. Materials and Methods:Each patient provided written consent to a human subject protocol approved by an institutional review board. Highspatial-resolution susceptibility-weighted 7.0-T MR images were obtained in 21 patients with MS. Contrast patterns in quantitative phase and R2* images, derived from 7.0-T data, were investigated in 220 areas defi ned as chronic MS lesions on conventional T2-weighted fl uid-attenuated inversion recovery, T2-weighted, and T1-weighted spin-echo images. The presence of positive or negative phase shifts (ie, decreased or increased MR frequency, respectively) was assessed in each lesion. In addition, postmortem MR imaging was performed at 7.0 T and 11.7 T, and its results were correlated with those of immunohistochemical staining specifi c for myelin, iron, and ferritin. Results:The majority (133 [60.5%] of 220) of the identifi ed lesions had a normal phase and reduced R2*. A substantial fraction of the lesions (84 [38.2%] of 220) had negative phase shift, either uniformly or at their rim, and a variety of appearances on R2* maps. These two lesion contrast patterns were reproduced in the postmortem MR imaging study. Comparison with histologic fi ndings showed that, while R2* reduction corresponded to severe loss of both iron and myelin, negative phase shift corresponded to focal iron deposits with myelin loss. Conclusion:Combined analysis of 7.0-T R2* and phase data may help in characterizing the pathologic features of MS lesions. The observed R2* decreases suggest profound myelin loss, whereas negative phase shifts suggest a focal iron accumulation.q RSNA, 2011Supplemental material : http://radiology.rsna.org/lookup /suppl

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“…The lower iron content in the Perl stain of the PD sample found here may be due to the fixation time being longer for the PD sample compared to the HC samples (z2 vs 1 year). 21,22 The mismatch between the hypointensity observed on the T2*-weighted MRI and Perl stains is interesting. Since the Perl stain is sensitive only to iron (III), this could be due to higher iron (II) content in PD brains, which could relate to the fixation process, but would also be consistent with increased oxidative stress due to ferrous iron in PD.…”

mentioning

confidence: 99%

“…Third, the low iron content in the Perl stain of the PD sample was paradoxical and indicates that future studies should use PM samples with similar fixation times. 21,22,31 Finally, it was difficult to distinguish between the SNpc and VTA, as both contain dopaminergic, neuromelanin-pigmented cells, but they can be separated based on the anatomical location, cell density (which is lower in VTA), or using the issuing fibers of the third cranial nerve as landmarks for VTA. This study identifies the substructure of the SNpc that is visible on 7 T T2*-weighted images 12 as nigrosome 1.…”

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confidence: 99%

Visualization of nigrosome 1 and its loss in PD

Blazejewska

Schwarz²,

Pitiot³

et al. 2013

Neurology

221

255

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Objective: This study assessed whether high-resolution 7 T MRI allowed direct in vivo visualization of nigrosomes, substructures of the substantia nigra pars compacta (SNpc) undergoing the greatest and earliest dopaminergic cell loss in Parkinson disease (PD), and whether any disease-specific changes could be detected in patients with PD.Methods: Postmortem (PM) midbrains, 2 from healthy controls (HCs) and 1 from a patient with PD, were scanned with high-resolution T2*-weighted MRI scans, sectioned, and stained for iron and neuromelanin (Perl), TH, and calbindin. To confirm the identification of nigrosomes in vivo on 7 T T2*-weighted scans, we assessed colocalization with neuromelanin-sensitive T1-weighted scans. We then assessed the ability to depict PD pathology on in vivo T2*-weighted scans by comparing data from 10 patients with PD and 8 age-and sex-matched HCs.Results: A hyperintense, ovoid area within the dorsolateral border of the otherwise hypointense SNpc was identified in the HC brains on in vivo and PM T2*-weighted MRI. Location, size, shape, and staining characteristics conform to nigrosome 1. Blinded assessment by 2 neuroradiologists showed consistent bilateral absence of this nigrosome feature in all 10 patients with PD, and bilateral presence in 7/8 HC. Many MRI studies have reported Parkinson disease (PD)-associated changes in the substantia nigra (SN). 1 However, delineating the boundaries and assessing neurodegeneration in the SN remains challenging. 2 Recently developed ultra-high-field MRI systems produce very high spatial resolution T2*-weighted images providing detailed SN morphologic information. Correlation of high-resolution MRI data and histology 3 may enable a more precise definition of the boundaries and substructures of the SN in vivo, and hence a more accurate demonstration of PD pathology.The SN is divided into the pars compacta (SNpc), which is densely packed with neuromelanin-containing dopaminergic cells, and the pars reticulata (SNpr), which is formed by loose aggregations of GABAergic medium and large neurons. 4 The majority of neurons in the SNpc project to the neostriatum (putamen and caudate nucleus). Five distinct subgroups of dopaminecontaining neurons in calbindin-negative zones within the SNpc, nigrosomes, have been identified using immunostaining for calbindin D 28K . 5 The largest, nigrosome 1, is lens-shaped and situated along the rostral/caudal axis of the SN in its dorsal part, at caudal and intermediate levels ( figure 8 of Damier et al. 5 ; figure e-1 on the Neurology ® Web site at www.neurology.org). Postmortem (PM) studies have shown dopaminergic neuronal loss in PD to be higher in the

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Leaching of Trace Elements from Biological Tissue by Formalin Fixation

Cited by 74 publications

References 10 publications

Tracking iron in multiple sclerosis: a combined imaging and histopathological study at 7 Tesla

Tracking iron in multiple sclerosis: a combined imaging and histopathological study at 7 Tesla

Chronic Multiple Sclerosis Lesions: Characterization with High-Field-Strength MR Imaging

Visualization of nigrosome 1 and its loss in PD

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