Amyloid Precursor Protein in Abusive Head Trauma Suspects

circle PURPOSE: To study orthograde axonal transport with amyloid precursor protein (APP-A4) immunohistochem-istry (IHC) in the retina and lamina cribrosa (LC) portion of the optic nerve in abusive head trauma (AHT) suspects. circle DESIGN: Retrospective, case-control study. circle METHODS: Seventy-two eyes from suspected AHT vic-tims referred by the Los Angeles Coroner and control eyes from nontraumatized infants were included. IHC was conducted using University of California, Irvine (UCI), Lab Medicine Department's standard protocol and results analyzed by light microcopy after paraffin process-ing. Quantitation of LC APP-A4 block was estimated in 21 cases with known survival using MetaMorph, a pro-prietary biomicroscopy imaging software. circle RESULTS: The presence or absence of APP-A4 label ac-cumulations in retinal ganglion cells, nerve fiber layer at the disc margin, and in LC axonal bundles were compared to matching tissues from nontraumatized control eyes with only background staining. Among the globes from AHT suspects with nerve heads available for study, 94% were positive for LC accumulation of marker. Among suspect AHT cases with known survival after injury of 1 to 1588 days, most demonstrated LC APP-A4 accumula-tions. circle CONCLUSIONS: Our findings reinforce a recent publi-cation based on APP-A4 IHC that demonstrated simi-lar orthograde axonal transport block in the LC in chil-dren with AHT and recommend that intraocular pres-sures be recorded and addressed in these patients. (Am J Ophthalmol 2022;240: 58-66. (c) 2022 Elsevier Inc. All rights reserved.)

Automated summary

This study investigated orthograde axonal transport of amyloid precursor protein (APP-A4) in the retina and lamina cribrosa (LC) portion of the optic nerve in abusive head trauma (AHT) suspects using immunohistochemistry. The findings revealed the accumulation of APP-A4 in LC and suggested that intraocular pressures be recorded and addressed in these patients.