Schistosomula, pre-adults and adults ofSchistosoma mansoniingest fluorescence-labelled albuminin vitroandin vivo: implication for a drug-targeting model

Abstract

SUMMARYObjective.Bilharziosis is one of the most important helminthal infections in humans and is caused by blood flukes of the genusSchistosoma.Three different life stages of the parasite occur within the mammalian host: schistosomula located in the skin, pre-adults located in the lung and adult worms located in the portal venous system. Erythrocytes are a major source of nutrient supply for adults. However, sources of nutrition for the developing stages are still unclear.Methods.To investigate whether schistosomula, pre-adults and adults ofSchistosoma mansoniingest human serum albumin (HSA)in vitro, these life stages were incubated with aminofluorescein-labelled human serum albumin (Afl-HSA) for 5 h. To test the uptake of albuminin vivo, the albumin conjugate was given intravenously toS. mansoniinfected NMRI mice 24 h before harvesting the 3 life stages.Results.In comparison to the control group schistosomula, pre-adults, and adults showed an accumulation of Afl-HSA within the oesophagus and intestinal caecumin vitroandin vivo.Conclusion.Our findings suggest that albumin seems to be a major source of energy supply for the early schistosomal life stages and an additive energy support for adult worms. Since albumin has been used successfully as a drug carrier for chemotherapeutic substances against malignant disorders, further studies will focus on albumin as a carrier for anthelminthics in a drug-targeting model.