Magnetite biomineralization in the human brain.

Kirschvink, Joseph L.; Kobayashi-Kirschvink, Atsuko; Woodford, Barbara J.

doi:10.1073/pnas.89.16.7683

Cited by 532 publications

(388 citation statements)

References 28 publications

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“…Biogenic magnetite has been reported in human brain tissue from studies dating back to 1992 and is present as an iron biomineral in many species [64][65][66]. However, in a recent SQUID magnetometry study, Hautot et al [67] reported elevated levels of biogenic magnetite in female AD subjects compared to both male and female controls.…”

Section: Iron-containing Compounds Related To Alzheimer Diseasementioning

confidence: 99%

Iron: The Redox-active Center of Oxidative Stress in Alzheimer Disease

et al. 2007

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Although iron is essential in maintaining the function of the central nervous system, it is a potent source of reactive oxygen species. Excessive iron accumulation occurs in many neurodegenerative diseases including Alzheimer disease (AD), Parkinson's disease, and Creutzfeldt-Jakob disease, raising the possibility that oxidative stress is intimately involved in the neurodegenerative process. AD in particular is associated with accumulation of numerous markers of oxidative stress; moreover, oxidative stress has been shown to precede hallmark neuropathological lesions early in the disease process, and such lesions, once present, further accumulate iron, among other markers of oxidative stress. In this review, we discuss the role of iron in the progression of AD.

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Section: Iron-containing Compounds Related To Alzheimer Diseasementioning

confidence: 99%

Iron: The Redox-active Center of Oxidative Stress in Alzheimer Disease

et al. 2007

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confidence: 99%

Magnetite pollution nanoparticles in the human brain

Maher

Ahmed

Karloukovski

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

817

627

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Biologically formed nanoparticles of the strongly magnetic mineral, magnetite, were first detected in the human brain over 20 y ago [Kirschvink JL, Kobayashi-Kirschvink A, Woodford BJ (1992) Proc Natl Acad Sci USA 89(16):7683-7687]. Magnetite can have potentially large impacts on the brain due to its unique combination of redox activity, surface charge, and strongly magnetic behavior. We used magnetic analyses and electron microscopy to identify the abundant presence in the brain of magnetite nanoparticles that are consistent with high-temperature formation, suggesting, therefore, an external, not internal, source. Comprising a separate nanoparticle population from the euhedral particles ascribed to endogenous sources, these brain magnetites are often found with other transition metal nanoparticles, and they display rounded crystal morphologies and fused surface textures, reflecting crystallization upon cooling from an initially heated, iron-bearing source material. Such high-temperature magnetite nanospheres are ubiquitous and abundant in airborne particulate matter pollution. They arise as combustion-derived, iron-rich particles, often associated with other transition metal particles, which condense and/ or oxidize upon airborne release. Those magnetite pollutant particles which are <∼200 nm in diameter can enter the brain directly via the olfactory bulb. Their presence proves that externally sourced iron-bearing nanoparticles, rather than their soluble compounds, can be transported directly into the brain, where they may pose hazard to human health.brain magnetite | magnetite pollution particles | Alzheimer's disease | combustion-derived nanoparticles | airborne particulate matter

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“…For example, ferritin-derived ferrihydrite in humans, with varying degrees of structural order, has been related to different neurodegenerative diseases (26). In this regard, biogenic ferrimagnetic crystals, identified as magnetite, that have been found in human brain tissues (27)(28)(29) may originate from biodegradation of a ferrihydrite precursor.…”

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confidence: 99%

Ordered ferrimagnetic form of ferrihydrite reveals links among structure, composition, and magnetism

Michel

Barrón

Torrent

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

340

393

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The natural nanomineral ferrihydrite is an important component of many environmental and soil systems and has been implicated as the inorganic core of ferritin in biological systems. Knowledge of its basic structure, composition, and extent of structural disorder is essential for understanding its reactivity, stability, and magnetic behavior, as well as changes in these properties during aging. Here we investigate compositional, structural, and magnetic changes that occur upon aging of "2-line" ferrihydrite in the presence of adsorbed citrate at elevated temperature. Whereas aging under these conditions ultimately results in the formation of hematite, analysis of the atomic pair distribution function and complementary physicochemical and magnetic data indicate formation of an intermediate ferrihydrite phase of larger particle size with few defects, more structural relaxation and electron spin ordering, and pronounced ferrimagnetism relative to its disordered ferrihydrite precursor. Our results represent an important conceptual advance in understanding the nature of structural disorder in ferrihydrite and its relation to the magnetic structure and also serve to validate a controversial, recently proposed structural model for this phase. In addition, the pathway we identify for forming ferrimagnetic ferrihydrite potentially explains the magnetic enhancement that typically precedes formation of hematite in aerobic soil and weathering environments. Such magnetic enhancement has been attributed to the formation of poorly understood, nano-sized ferrimagnets from a ferrihydrite precursor. Whereas elevated temperatures drive the transformation on timescales feasible for laboratory studies, our results also suggest that ferrimagnetic ferrihydrite could form naturally at ambient temperature given sufficient time.crystal structure | disorder | nano-sized ferrimagnets | soil formation | strain T he structural and physical properties of ferrihydrite, an exclusively nano-sized ferric oxyhydroxide, are of importance in explaining its chemical reactivity and wide variety of occurrences. In both pristine and contaminated soils and sediments, ferrihydrite acts as a natural filter of inorganic contaminants through sorption reactions, thus affecting their transport and fate in the environment. Biomineralization of ferrihydrite as the inorganic iron core in ferritin-the protein mainly involved in iron storage and homeostasis in the human body-also occurs in a vast number of organisms (1). Bloom-forming marine diatoms, for example, use ferritin for enhanced iron storage (2), which suggests that ferrihydrite may also have underlying importance in primary productivity in the world's oceans.A well-known example of a nanomineral (3), ferrihydrite has no known crystalline counterpart formed in the laboratory or found in nature. As such, the basic crystal structure (4-7) and physical properties of ferrihydrite [e.g., density, composition (7, 8), and magnetic properties (9-14)] have remained controversial. A variety of structural models ha...

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Magnetite biomineralization in the human brain.

Cited by 532 publications

References 28 publications

Iron: The Redox-active Center of Oxidative Stress in Alzheimer Disease

Iron: The Redox-active Center of Oxidative Stress in Alzheimer Disease

Magnetite pollution nanoparticles in the human brain

Ordered ferrimagnetic form of ferrihydrite reveals links among structure, composition, and magnetism

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