Hemosiderosis in St. Kitts African green monkeys (Chlorocebus sabaeus)

Abstract

Hepatic hemosiderosis has not been systematically studied in African green monkeys (Chlorocebus sabaeus). We aimed to determine the prevalence of histologic hepatic hemosiderosis in this species, demographic predictors of its presence and severity, and the quantitative relationship between histological grade and hepatic iron concentration. We evaluated liver samples of 155 African green monkeys from a research colony in St. Kitts (24 juveniles, 89 adults, 42 geriatrics) using histology (hematoxylin and eosin, Perls Prussian blue) to semiquantitatively grade (0-4) hemosiderin deposits. Quantitative hepatic iron was measured via coupled plasma mass spectrometry in 146 samples. Overall, 63.9% (99/155; P < .001 vs 50%) exhibited histological hemosiderin deposits. The grade distribution was 52 (33.5%) grade 0, 29 (18.7%) grade 1, 23 (14.8%) grade 2, 25 (16.1%) grade 3, and 26 (16.8%) grade 4. Wild-caught origin was protective (odds ratio (OR) = 0.10, 95% confidence interval (CI) = 0.04-0.29, P < .001), while geriatric age was associated with iron accumulation (OR = 8.92, 95% CI = 2.06-10.61, P = .003). Ordinal regression confirmed lower odds of higher grades in wild-caught (OR = 0.095, 95% CI = 0.047-0.193, P < .001) and higher odds of higher grades in adult monkeys (OR = 4.2, 95% CI = 1.43-12.35, P = .009). Trend tests (z = 9.81, P < .0001) and Spearman's ρ = 0.82 (P < .0001) confirmed a strong association between pathology and iron burden. Recommended iron requirements may be excessive for certain life stages in this species. Colony-born and younger animals are at highest risk, while adult males show protection. Histological grading correlates strongly with quantitative iron measures, validating its use as a semiquantitative surrogate.

Keywords: background lesion; hemochromatosis; hemosiderosis; iron accumulation; kidneys; liver; nonhuman primate; secondary hemosiderosis.