Regional brain iron mapping in obstructive sleep apnea adults

Area of Science:

• Neuroimaging
• Sleep Medicine
• Neurology

Background:

• Obstructive sleep apnea (OSA) is linked to white matter injury and neurodegeneration.
• Impaired glial cells in OSA may increase brain iron levels, but regional iron loads are not well understood.

Purpose of the Study:

• To investigate regional brain iron load in adults with OSA before and after continuous positive airway pressure (CPAP) treatment.
• To compare brain iron levels in OSA patients with healthy controls using T2∗-relaxometry.

Main Methods:

• T2∗-weighted MRI scans were performed on 35 OSA adults and 67 controls.
• R2∗ maps were calculated and analyzed to compare iron levels between groups and over time (3 and 9 months of CPAP treatment).
• Statistical analyses included ANCOVA and paired t-tests to assess differences in R2∗ values.

Main Results:

• Before CPAP, OSA patients showed higher R2∗ values (indicating more iron) in areas including the amygdala, insula, hippocampus, cerebellum, medulla, and pons compared to controls.
• After 3 months of CPAP, R2∗ values increased further in the cerebellum, thalamus, and cingulate.
• After 9 months of CPAP, R2∗ values in OSA patients returned to baseline levels, with no regions showing increased iron compared to controls.

Conclusions:

• OSA patients exhibit elevated brain iron content compared to controls.
• Iron accumulation in the brain progresses during the initial phase of CPAP treatment but begins to resolve after 9 months.
• Interfering with iron accumulation in OSA may offer a therapeutic strategy to mitigate brain injury.