Amyloid Precursor Protein in Abusive Head Trauma Suspects.

Area of Science:

• Ophthalmology
• Neuropathology
• Forensic Medicine

Background:

• Abusive head trauma (AHT) is a severe form of inflicted traumatic brain injury in infants.
• Orthograde axonal transport is crucial for neuronal health, and its disruption can lead to cell death.
• Amyloid precursor protein (APP-A4) is a marker of axonal injury and transport deficits.

Purpose of the Study:

• To investigate orthograde axonal transport deficits in the retina and optic nerve of suspected abusive head trauma (AHT) cases.
• To utilize amyloid precursor protein (APP-A4) immunohistochemistry (IHC) as a biomarker for axonal transport disruption.
• To compare findings in AHT suspects with control cases of non-traumatized infants.

Main Methods:

• A retrospective case-control study involving 72 eyes from suspected AHT victims and control eyes.
• Immunohistochemistry (IHC) for APP-A4 was performed on retinal and optic nerve (lamina cribrosa - LC) tissues.
• Quantification of APP-A4 accumulation in the LC was assessed using specialized imaging software in cases with known survival.

Main Results:

• Accumulations of APP-A4 were observed in the retinal ganglion cells, nerve fiber layer, and LC axonal bundles of AHT suspects.
• 94% of AHT suspect eyes with available nerve heads showed positive LC APP-A4 accumulation.
• Most AHT cases with documented survival after injury (1-1588 days) exhibited LC APP-A4 accumulation.

Conclusions:

• The study confirms orthograde axonal transport block in the lamina cribrosa of children with AHT, as evidenced by APP-A4 IHC.
• These findings align with prior research demonstrating similar axonal transport deficits in AHT.
• It is recommended to record and manage intraocular pressure in infants diagnosed with or suspected of AHT.