Schistosomula, pre-adults and adults of Schistosoma mansoni ingest fluorescence-labelled albumin in vitro and in vivo: implication for a drug-targeting model.
OBJECTIVE
Bilharziosis is one of the most important helminthal infections in humans and is caused by blood flukes of the genus Schistosoma. 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 of Schistosoma mansoni ingest 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 albumin in vivo, the albumin conjugate was given intravenously to S. mansoni infected 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 caecum in vitro and in vivo.


CONCLUSIONS
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.
Holtfreter
M C
MC
Division of Tropical Medicine and Infectious Diseases, Department of Internal Medicine, University of Rostock, Ernst-Heydemann Strasse 6, 18057 Rostock, Germany.
Loebermann
M
M
Frei
E
E
Riebold
D
D
Wolff
D
D
Hartung
G
G
Kinzelbach
R
R
Reisinger
E C
EC
D000818:Animals; D021461:Animals, Outbred Strains; D000871:Anthelmintics / Q000494:pharmacology; D004195:Disease Models, Animal; D016503:Drug Delivery Systems; D005260:Female; D019793:Fluorescein / Q000378:metabolism*; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000469:parasitology; D051379:Mice; D008856:Microscopy, Fluorescence; D012550:Schistosoma mansoni / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D012555:Schistosomiasis mansoni / Q000469:parasitology*; D012709:Serum Albumin / Q000378:metabolism*; D012867:Skin / Q000378:metabolism / Q000469:parasitology
D000871:Anthelmintics; D012709:Serum Albumin; D019793:Fluorescein