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Siderotic cerebral macrophages in the acquired immunodeficiency syndrome
B B Gelman1, M G Rodriguez-Wolf, J Wen
1Department of Pathology, University of Texas Medical Branch, Galveston 77550.
Abstract:
Excessive hemosiderin-laden perivascular macrophages have been described in the brains of patients with the acquired immunodeficiency syndrome (AIDS) who underwent autopsy; its meaning remains unclear. In the brains of 53 patients with AIDS who consecutively underwent autopsy, we quantified the abnormality, elucidated its relationship to the pathologic features of AIDS, and asked if there was some relationship to endogenous iron storage and transport proteins in brain macrophages and microglia. The number of perivascular siderotic macrophages was significantly increased in patients with AIDS compared with age-matched control subjects. Macrophage siderosis was strongly correlated with the presence of disseminated mycobacterial infection and vacuolar myelopathy at autopsy; a generalized wasting (cachexia) also was related significantly. Many other pathologic abnormalities were not related, including putative human immunodeficiency virus-specific neuropathologic changes such as multinucleated cells and myelin pallor. Activated macrophages and microglial cells in the central nervous system had dense intracytoplasmic accumulation of ferritin (iron storage protein) in AIDS and non-AIDS patients. These results suggest that siderosis of cerebral macrophages is related to an ill-defined nonspecific systemic imbalance associated with the breakdown of abundant stores of endogenous intracellular ferritin. Understanding chronic "secondary" effects of human immunodeficiency virus type 1 infection will become increasingly important as improved survival in patients with AIDS is realized.
Insights
Brain macrophages accumulate excess iron in patients with acquired immunodeficiency syndrome (AIDS). This iron buildup correlates with infections and wasting, suggesting a systemic imbalance rather than direct HIV effects.
Area of Science:
- Neuropathology
- Immunology
- Iron Metabolism
Background:
- Perivascular hemosiderin-laden macrophages are observed in acquired immunodeficiency syndrome (AIDS) brains, but their significance is unknown.
- Iron accumulation in the brain may contribute to neuropathology in various conditions.
Purpose of the Study:
- To quantify perivascular macrophage siderosis in AIDS patients.
- To correlate this abnormality with AIDS-related pathology and endogenous iron proteins.
- To investigate the relationship between brain iron deposition and human immunodeficiency virus (HIV) infection.
Main Methods:
- Autopsy brain tissue analysis from 53 AIDS patients and age-matched controls.
- Quantification of perivascular siderotic macrophages.
- Assessment of iron storage proteins (ferritin) in macrophages and microglia.
- Correlation analysis with clinical and pathological features.
Main Results:
- Significantly increased perivascular siderotic macrophages in AIDS patients compared to controls.
- Macrophage siderosis strongly correlated with disseminated mycobacterial infection and vacuolar myelopathy.
- No significant correlation with HIV-specific neuropathological changes like multinucleated cells.
- Activated macrophages and microglia showed intracytoplasmic ferritin accumulation in both AIDS and non-AIDS cases.
Conclusions:
- Cerebral macrophage siderosis in AIDS is linked to systemic imbalances and ferritin breakdown, not directly to HIV-specific neuropathology.
- This finding highlights the importance of understanding secondary effects of HIV infection with improved patient survival.