In vitro study of iron deposition in normal human brains: An Indian scenario

Abstract

Background: An increase in brain iron is a normal physiological process during brain development but excess accumulation is a risk factor for various neurodegenerative diseases. Thus, knowledge of the normal range of brain iron content is mandatory. The present study was planned to collect normative data on iron deposition in human brains by in vitro analysis.

Materials and Methods: Iron deposition in basal ganglia was determined by Perl's staining in 31 (18 males, 13 females) non-pathological postmortem brains aged from 18 to 80 years and by inductively coupled plasma mass spectrometry (ICP-MS) in 13 of them (seven males, six females). After conventional paraffin embedding, 5µm thick sections were prepared, fixed and stained with freshly prepared Perl's stain along with a control section. For ICP-MS analysis, approximately 12-13mg samples of tissue from each region of interest were dried, weighed and digested with 2ml of concentrated nitric acid. After digestion, the samples were dissolved in ICP grade water for trace analysis and the iron concentration was determined against standards using an ICP-MS analyzer and recorded in parts per billion (ppb).

Results: Nonheme iron deposits were observed in the globus pallidus in 16.13% of cases with no significant sex difference. Iron was deposited in the perivascular area, predominantly in the tunica media and tunica adventitia. ICP-MS analysis revealed the highest iron concentration of 595 ppb (0.595 µg/gm tissue) in the globus pallidus with no significant gender or age related differences.

Conclusion: The present study revealed a low (16%) incidence of brain iron deposition in normal adult postmortem brains. This article is protected by copyright. All rights reserved.

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