Postmortem Findings from the Wake Forest University Radiation Late Effects Cohort of Rhesus Monkeys (Macaca mulatta)

George W Schaaf ¹, John D Olson ¹, Brooke T Kahn ²

⁰Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina.

Radiation Research +

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July 18, 2025

View abstract on PubMed

Summary

Long-term survivors of total-body irradiation (TBI) in non-human primates (NHPs) showed increased neoplasia and multi-organ fibrosis. These findings suggest an accelerated-aging phenotype in radiation survivors, providing insights into late radiation effects.

Area Of Science

Radiation oncology
Veterinary pathology
Non-human primate research

Background

The Wake Forest Radiation Late Effects Cohort (RLEC) comprises rhesus non-human primates (NHPs) surviving total-body irradiation (TBI).
This cohort has been monitored for over 16 years, providing long-term data on radiation survivors.

Purpose Of The Study

To present postmortem findings from deceased RLEC members.
To analyze systemic, long-term pathology in NHPs years after TBI.
To identify potential accelerated-aging phenotypes in radiation survivors.

Main Methods

A comprehensive necropsy and histopathologic examination of 36 organs and tissues was performed on 104 deceased animals (87 irradiated, 17 controls).
Necropsy reports were reviewed by veterinary pathologists, and diagnoses were cataloged.
Statistical analysis (Fisher's exact test) was used to compare lesion prevalence between irradiated and control groups.

Main Results

Common findings in irradiated NHPs included multi-organ fibrosis and chronic inflammation.
An increased occurrence of neoplasia was observed in irradiated animals compared to controls.
Despite age differences, similar lesions appeared in both irradiated and control animals, suggesting accelerated aging.

Conclusions

Long-term TBI in NHPs leads to significant late effects, including fibrosis, inflammation, and neoplasia.
The observed pathologies suggest an accelerated-aging phenotype in radiation survivors.
These findings establish a foundation for molecular and translational studies on radiation late effects.