Distribution of amyloid‐β precursor protein‐immunoreactive axons differs according to the severity of cerebral ischemia in autopsy brains

Amyloid‐β precursor protein (APP) immunohistochemistry has been used to detect axonal injury in forensic neuropathology. However, axonal injury caused by cerebral ischemia has not been investigated by APP immunohistochemistry in detail. In particular, it is unknown if there is a correlation between the prognosis of cerebral ischemia and the distribution of axonal injury detected by APP immunohistochemistry. To address this issue, we compared the distribution of APP‐immunoreactive axons in autopsy brains including lesions of acute phase of cerebral infarction in the territory of the middle cerebral artery (MCA) or internal carotid artery (ICA) with the degree of severity. The presence or absence of a midline shift was used as an indicator of the severity of cerebral ischemia. We identified a difference in the distribution of APP‐immunoreactive axons between cases with and without a midline shift. In both the groups, APP‐immunoreactive axons were detected at the margin of the ischemic lesions; however, only in cases with a midline shift, intense APP‐immunoreactive axons were also found in areas other than the MCA and ICA territories, including the white matter of the cerebral hemispheres ipsilateral and contralateral to the ischemic lesions. This distribution was different from that of acute global cerebral ischemia cases reported previously. Our results indicate that the distribution of APP‐immunoreactive axons differs according to the severity and type of cerebral ischemia, suggesting that the distribution of APP‐immunoreactive axons is associated with the prognosis of cerebral ischemia.