A polysaccharide isolated from the brown seaweed Sargassum stenophyllum exerts antivasculogenic effects evidenced by modified morphogenesis.
A polysaccharide (Sarg) extracted from the brown marine alga Sargassum stenophyllum was studied for its antivasculogenic effects in both in vivo and in vitro assays, as well as for its capacity to modify embryonic morphogenetic processes endogenously regulated by bFGF, a well-known angiogenic stimulator. The antivasculogenic activity of Sarg (6-1500 microg/implant) was evaluated in a chick yolk sac membrane assay and the embryonic morphogenesis was measured as the percentage cephalic length. Sarg alone (96-1500 microg/implant) and co-administered with hydrocortisone (HC; 156 microg/implant) decreased the vitelline vessel number by 23-100% and 54-100% respectively. The polysaccharide potentiated the antivasculogenic effect of HC (42% inhibition). Basic fibroblast growth factor-stimulated vasculogenesis (141% of vessels as compared to control) was partially reversed by Sarg. The treatment with Sarg also decreased the percentage cephalic length of 3.5- and 4-day chick embryos (as cultured in vivo and in vitro, respectively), uncoupled from any impairment in the body shape or embryotoxic effect. Due to polyanionic characteristics of Sarg, which are similar to those seen in the heparin molecule, we suggest that this polysaccharide should modulate the activity of heparin-binding vascular growth factors (such as bFGF, which also acts as a morphogen) mimetically interfering with heparan sulfate proteoglycans during microvessel formation.
Dias
Paulo Fernando
PF
Department of Pharmacology, Biological Sciences Center (CCB), Block D, Federal University of Santa Catarina (UFSC), University Campus-Trindade, Florianópolis, 88.049-900, SC, Brazil. paulus@mbox1.ufsc.br
Siqueira
Jarbas Mota
JM
Maraschin
Marcelo
M
Ferreira
Antônio Gilberto
AG
Gagliardi
Antônio Ricardo
AR
Ribeiro-do-Valle
Rosa Maria
RM
D020533:Angiogenesis Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D001808:Blood Vessels / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000098:blood supply*; D004305:Dose-Response Relationship, Drug; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D006854:Hydrocortisone / Q000494:pharmacology; D015394:Molecular Structure; D009024:Morphogenesis / Q000187:drug effects; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D044647:Sargassum / Q000737:chemistry; D013997:Time Factors
D020533:Angiogenesis Inhibitors; D011134:Polysaccharides; D016222:Fibroblast Growth Factor 2; D006854:Hydrocortisone