Brain iron in sickle cell disease?

In this issue of Blood, Miao et al have investigated the role of brain iron accumulation and silent cerebral infarction (SCI) in sickle cell disease (SCD), as well as considered whether these pathologies might be connected. Although iron deposition may play a crucial role in organ damage in SCD, the mechanisms involved are unclear, and there are few studies in the brain. To investigate further, Miao et al exploited the emerging technique of magnetic resonance imaging (MRI) quantitative susceptibility mapping (QSM), which provides a measure of tissue magnetic susceptibility that is strongly correlated with its iron content. They report QSM evidence for iron accumulation in the putamen, substantia nigra, and red nucleus in adolescent and young adult patients with SCD compared with controls. They also found significantly higher susceptibility in the globus pallidus and substantia nigra of SCD patients with SCI. When combining SCD patients with controls, they found a significant increase in susceptibility with age in the substantia nigra (see figure) and other deep gray matter regions, as originally documented histologically and confirmed in R2* and QSM MRI studies in healthy people