title: Fucoidan interferes with Porphyromonas gingivalis-induced aneurysm enlargement by decreasing neutrophil activation.
abstract: OBJECTIVE
  Neutrophils have been shown to be involved in all stages of human and experimental abdominal aortic aneurysm (AAA) development. The initial processes of neutrophil rolling and trapping in the intraluminal thrombus (ILT) are mediated mainly by P-selectin expressed by activated platelets. In the present study, we propose to evaluate the beneficial effect of fucoidan, a competitive binding agent of P-selectin, on aneurysmal growth in a rat model of aortic aneurysm with neutrophil enrichment of the ILT induced by repeated episodes of weak bacteremia.
  
  
  METHODS
  Sixty Lewis rats with experimental AAAs, developed from decellularized aortic xenografts, were divided into four groups. Two groups were used as controls: group fucoidan control (FC) was treated with 200 mg of fucoidan (F) delivered by 2 mL, 4-week osmotic pumps placed intraperitoneally before closing the abdomen, and group C received saline instead of fucoidan. Two more groups were injected weekly with Porphyromonas gingivalis (P. gingivalis [Pg]): group F+Pg received 200 mg of intraperitoneal fucoidan and group Pg received saline. AAAs were harvested after 4 weeks and peripheral blood was sampled at that time. Cell-free DNA (cf-DNA) and myeloperoxydase (MPO) antigen concentrations were determined in plasma and in AAA-conditioned media. Histology and P-selectin immunostaining were performed on AAA tissue samples.
  
  
  RESULTS
  Comparing rats injected with Pg, those receiving fucoidan presented reduced aneurysmal diameter. Histologic analysis of AAAs showed that fucoidan reduced the ILT thickness in Pg-injected rats, with fewer trapped neutrophils, and with signs of a healing process, as observed in control group C. Immunohistological analysis revealed a substantial decrease in P-selectin immunostaining at the luminal surface of aneurysms in fucoidan-treated rats compared to the other groups, suggesting an interaction between fucoidan and P-selectin. A significant decrease in MPO concentrations in both plasma and conditioned medium was induced by fucoidan treatment in Pg-injected rats, reflecting a pacification of the ILT biological activity. This effect was associated with a reduction in neutrophil activation and apoptosis, reflected by a significant decrease in cf-DNA concentration in both plasma and conditioned medium of fucoidan-treated rats.
  
  
  CONCLUSIONS
  Our results suggest that fucoidan has a beneficial effect on experimental aneurysmal degeneration by decreasing neutrophil activation in the ILT enhanced by weak pathogen contamination. This effect seems to be related to its interaction with P-selectin, which may decrease the trapping of neutrophils into the ILT. Fucoidan could represent a therapeutic option in AAAs to decrease the neutrophil activation involved in the degenerative process of aneurysmal expansion and rupture.
authors.affiliation: Department of Cardiovascular Remodelling, 1UMR 698 Institut National de la Sante et de la recherche Medicale, Université Paris 7, Hôpital Xavier Bichat, Paris, France. jean-marc.alsac@egp.aphp.fr
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Alsac
authors.forename: Sandrine
authors.initials: S
authors.lastname: Delbosc
authors.forename: Martin
authors.initials: M
authors.lastname: Rouer
authors.forename: Clément
authors.initials: C
authors.lastname: Journé
authors.forename: Liliane
authors.initials: L
authors.lastname: Louedec
authors.forename: Olivier
authors.initials: O
authors.lastname: Meilhac
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Michel
mesh_terms: D000785:Aneurysm, Infected / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D017544:Aortic Aneurysm, Abdominal / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D017209:Apoptosis / Q000187:drug effects; D016866:Bacteroidaceae Infections / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D015415:Biomarkers / Q000097:blood; D004247:DNA / Q000097:blood; D004195:Disease Models, Animal; D006168:Guinea Pigs; D007150:Immunohistochemistry; D007263:Infusions, Parenteral; D018375:Neutrophil Activation / Q000187:drug effects*; D009504:Neutrophils / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D019007:P-Selectin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009195:Peroxidase / Q000097:blood; D011134:Polysaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D016966:Porphyromonas gingivalis / Q000302:isolation & purification*; D051381:Rats; D011917:Rats, Inbred Lew; D013997:Time Factors
chemical_list: D015415:Biomarkers; D019007:P-Selectin; D011134:Polysaccharides; D004247:DNA; C007789:fucoidan; D009195:Peroxidase