title: In vitro and in vivo activities of arachidonic acid against Schistosoma mansoni and Schistosoma haematobium.
abstract: The development of arachidonic acid (ARA) for treatment of schistosomiasis is an entirely novel approach based on a breakthrough discovery in schistosome biology revealing that activation of parasite tegument-bound neutral sphingomyelinase (nSMase) by unsaturated fatty acids, such as ARA, induces exposure of parasite surface membrane antigens to antibody binding and eventual attrition of developing schistosomula and adult worms. Here, we demonstrate that 5 mM ARA leads to irreversible killing of ex vivo 1-, 3-, 4-, 5-, and 6-week-old Schistosoma mansoni and 9-, 10-, and 12-week-old Schistosoma haematobium worms within 3 to 4 h, depending on the parasite age, even when the worms were maintained in up to 50% fetal calf serum. ARA-mediated worm attrition was prevented by nSMase inhibitors, such as CaCl(2) and GW4869. Scanning and transmission electron microscopy revealed that ARA-mediated worm killing was associated with spine destruction, membrane blebbing, and disorganization of the apical membrane structure. ARA-mediated S. mansoni and S. haematobium worm attrition was reproduced in vivo in a series of 6 independent experiments using BALB/c or C57BL/6 mice, indicating that ARA in a pure form (Sigma) or included in infant formula (Nestle) consistently led to 40 to 80% decrease in the total worm burden. Arachidonic acid is already marketed for human use in the United States and Canada for proper development of newborns and muscle growth of athletes; thus, ARA has potential as a safe and cost-effective addition to antischistosomal therapy.
authors.affiliation: Zoology Department, Faculty of Science, Cairo University, Giza 12613, Egypt. rashika@mailer.eun.eg
authors.forename: Rashika
authors.initials: R
authors.lastname: El Ridi
authors.forename: Marwa
authors.initials: M
authors.lastname: Aboueldahab
authors.forename: Hatem
authors.initials: H
authors.lastname: Tallima
authors.forename: Mohamed
authors.initials: M
authors.lastname: Salah
authors.forename: Noha
authors.initials: N
authors.lastname: Mahana
authors.forename: Samia
authors.initials: S
authors.lastname: Fawzi
authors.forename: Shadia H
authors.initials: SH
authors.lastname: Mohamed
authors.forename: Omar M
authors.initials: OM
authors.lastname: Fahmy
mesh_terms: D000284:Administration, Oral; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology* / Q000627:therapeutic use*; D006224:Cricetinae; D005260:Female; D006801:Humans; D008297:Male; D008647:Mesocricetus; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D021261:Parasitic Sensitivity Tests; D012548:Schistosoma haematobium / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D012550:Schistosoma mansoni / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D012553:Schistosomiasis haematobia / Q000188:drug therapy* / Q000469:parasitology; D012555:Schistosomiasis mansoni / Q000188:drug therapy* / Q000469:parasitology; D016896:Treatment Outcome
chemical_list: D016718:Arachidonic Acid