Bioactivités des Polysaccharides marins en Santé humaine et animale (Mise à jour)

National audienc

A randomized controlled double-blind clinical trial comparing versus placebo the effect of an edible algal extract (Ulva Lactuca) on the component of depression in healthy volunteers with anhedonia

Abstract Background The effects of the seaweed extract were evaluated on the animal model equivalent of depression compared with a control group treated with the carrier (spring water) and a reference group treated with Imipramine and showed significative effect. This clinical trial was intended to confirm in humans the potential efficacy identified in animals. The primary objective was to compare against a placebo the effect of Ulva L.L extract in healthy volunteers whose anhedonia was characterized by a component of depression. Methods Single-centre double-blind randomized placebo-controlled clinical trial on parallel arms of two groups of 45 subjects. The study could include men or women aged 18 to 65 years with anhedonia characterized by a Snaith Hamilton Pleasure Scale score (SHAPS) of ≥5 and feeling low morale for at least four weeks characterized by a component of depression evaluated on the Quick Inventory of Depressive Symptomatology – Self Report (QIDS–SR). Evaluation criteria: QIDS-SR; Patient Global Improvement Impression (PGII) and Clinical Global Improvement Impression (CGII). Results 86 subjects were included in the trial: 42 in the placebo group and 44 Ulva group. At D84, QIDS-SR significantly decreased more in the Ulva.L.L. group than in the placebo group (p: 0.0389). This difference is essentially linked to an improvement of the sleep disorders (p: 0.0219), of the psychomotor consequences (p: 0.002) and of the nutrition behaviour (p: 0.0694). 90.1% have the feeling of being improved in the Ulva group vs 72.5% in the placebo group (p: 0.0114) and in parallel 90.9% of the practitioners have the feeling that the subject has improved vs 70.8% (p: 0.0214). Conclusion This double-blind randomized placebo-controlled trial shows that daily intake for three months of a water-soluble extract of Ulva L.L. continues to significantly improve the component of depression of subjects presenting anhedonia compared with a placebo. Trial registration Trial retrospectively registred on ClinicalTrial.gov under ID: NCT03545399 Date: 05/22/2018

Stimulation de l’immunité innée par des polysaccharides sulfatés extraits d’algue : une alternative aux antibiotiques

International audienc

Ulvane, un polysaccharide sulfaté d’Ulva armoricana, stimule la réponse immunitaire intestinale par un mécanisme impliquant la voie de signalisation TLR4/Akt

Session : Santé animaleThe biological activities of water-soluble sulfated polysaccharides of green algae (Ulvans) are explored with the aim of their being used as bioactive molecules for human and animal health. A purified fraction of ulvans was prepared from the green algae Ulva armoricana harvested in the Brittany region (France) and tested for its capacity to stimulate the immune response of the gut using an in vitro system of porcine intestinal epithelial cells (IPEC-1). RT-qPCR and ELISA analysis showed a significant increase in mRNA and protein expression of cytokines such as CCL20, IL8, and TNFalpha. By using human embryonic kidney HEK293 reporter cell lines for pattern recognition receptors, ulvan was found to stimulate mostly TLR4. We also examined this fraction’s effect on different signaling pathways involved in activating cytokine gene expression. Western blot analysis of ulvan-treated HEK293-TLR4 cells showed an increase in Akt and the p65 subunit of the nuclear factor-κB (NFκB) phosphorylation. Inhibition of Akt phosphorylation with specific inhibitor abrogated ulvan enhancement of IL-8 secretion. The overall results showed that ulvan is an immunostimulator compound by itself, and furthermore, it could be used to encapsulate and deliver TLR ligands to relevant immune cells to strongly enhance adjuvanticity and immunity in vaccination strategies

Ulvan from <em>Ulva Armoricana</em> (Chlorophyta) Activates the PI3K/AKT Signalling Pathway via TLR4 to Induce Intestinal Cytokine Production

International audienc

Ulvan from Ulva armoricana (Chlorophyta) activates the PI3K/Akt signalling pathway via TLR4 to induce intestinal cytokine production

The authors wish to thank Christelle Gouin (Amadeite) for the production of the demineralized algal extracts and for her contribution to the proximate analyses and Dr. Nathalie Guriec (CHU Brest) for the LPS analysis. We also gratefully acknowledge Dr. Isabelle Oswald (Toxalim Unit, INRA center of Toulouse, France) for kindly providing the IPEC-1 cell line.International audienceThe biological activities of water-soluble sulfated polysaccharides of green algae (ulvans) have been explored for use as bioactive molecules for the benefit of human and animal health. A purified ulvan fraction was prepared from the green algae Ulva armoricana harvested in the Brittany (France) and tested for its capacity to stimulate the immune response of the gut using an in vitro system of porcine intestinal epithelial (IPEC-1) cells. RT-qPCR and ELISA analyses showed a significant increase in the mRNA and protein expression of cytokines such as CCL20, IL8, and TNFα. Using human embryonic kidney (HEK) 293 reporter cell lines for pattern recognition receptors, ulvan was found to primarily stimulate TLR4. We also examined the effect of the ulvan fraction on different signalling pathways involved in the activation of cytokine gene expression. Western blot analyses of ulvan-treated HEK293-TLR4 cells showed an increase in the phosphorylation of Akt and the p65 subunit of nuclear factor-κB. Inhibition of Akt phosphorylation with the specific inhibitor abrogated the ulvan-mediated enhancement of IL-8 secretion. The overall results showed that ulvan is an immunostimulatory compound by itself, and furthermore, it could be used to effectively complex and deliver TLR ligands to relevant immune cells in vaccination strategies

Marine Sulfated polysaccharide stimulates the expression of response mediators of the immune system

International audienc

Sulfated polysaccharides-rich extract of Ulva armoricana green algae exhibits an antimicrobial activity and stimulates cytokine expression by intestinal epithelial cells

National audienc

L'activité antibactérienne et immunomodulatrice d'un extrait d'algue verte riche en polysaccharides sulfatés

Session Santé AnimaleAntibiotics have been used for a long time in pig production to protect animals against pathogens. However, EU policy has been adopted to implement a sustainable production without adding antibiotics as growth promoters. Marine algae contain in their cell wall water-soluble sulfated polysaccharides with potential biological activities such as anticoagulant, antiviral, antibacterial and immunomodulating activities that are being explored to be used as an effective alternative to antibiotics. A crude extract containing sulfated polysaccharides was prepared from the green algae Ulva armoricana harvested in Brittany region (France) and tested for its antibacterial activity against five strains of bacterial pathogens: Salmonella Typhimurium, Staphylococcus aureus, Listeria monocytogenes, E. coli O78 and E. coli K88. The obtained results showed that this extract was more effective in inhibiting the growth of S. aureus than those of L. monocytogenes, E. coli K88 and E. coli O78. Furthermore, the ability of the extract to stimulate the expression of the immune response mediators was evaluated using an in vitro system of porcine differentiated intestinal epithelial cells IPEC-1. Analysis by RT-qPCR showed increased expression of several cytokines including TNF, IL-1, IL-6, IL-8 and CCL20. This stimulation of immune response factor expression involved the activation of TLR4 receptor. These results suggest that this extract could be used as a new prophylactic strategy to stimulate the immune response of animals and to protect mucosal tissues against pathogens