Outcomes in mice with abdominal angiostrongyliasis treated with enoxaparin

Abstract

Abdominal angiostrongyliasis (AA) is caused by the nematode Angiostrongylus costaricensis. Parasite-associated thrombosis of mesenteric vessels may lead to intestinal infarction, which might be prevented with anti-thrombotic agents. This study assessed the effect of enoxaparin on survival and pathological findings in Swiss mice with AA. In this experiment, 24 mice were infected with A. costaricensis (10 L3 per animal) followed by treatment with subcutaneous enoxaparin (40 mg/kg/day) or water (sham), starting from 15 days post-infection (dpi) and continued until animal death. Animals were monitored until death or sacrifice at the 50th dpi. Ten mice (42%) were dead after 36 ± 8 dpi. Of these, five (50%) were treated with enoxaparin. Animals treated with enoxaparin and sham did not differ in terms of weight loss (median, 1.3 vs. 4.2 g; P = 0.303) and macroscopical findings. Microscopically, no difference was found in regard to vascular granuloma (median grade, 2 vs. 3; P = 0.293) and presence of either vasculitis (75% vs. 100%; P = 0.217), mesenteric thrombosis (33% vs. 50%; P = 0.680), or bowel necrosis (25% vs. 50%; P = 0.400). Mice dead before the 50th dpi showed more pneumonia (90% vs. 21%; P = 0.002), bowel infarction (40% vs. 0%; P = 0.02), and purulent peritonitis (60% vs. 7%; P = 0.008) compared to survivors. Prophylactic enoxaparin in mice did not prevent tissue damage and mortality related with AA. The lower prevalence of mesenteric thrombosis and bowel infarction regardless of treatment were notorious. Frequent septic complications suggest the need of studies addressing the effect of antibiotics in AA.