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With sadness we have been informed that in July our colleague Jean-François Savouret passed away. A former GREMI member for a long time, he resigned in 2012 for health problems. He actively participated in the organization of the 10th World Congress on Inflammation that we organized at the Palais des Congrès in 2011. A dedicated member, he always proposed short and pertinent names and themes for our scientific meetings. His former collaborators have organized a scientific meeting to be held on Friday January 30, 2015 in his honor. If you wish to attend this meeting, please find attached a pdf with all the pertinent information. Inscription


"Woman in Inflammation Science Award - 11th World Congress on Inflammation in Natal (Brazil)"
Nathalie Vergnolle, our GREMI colleague, has been the recipient on September 24, 2013, of the “Woman in Inflammation Science Award”. This prize is presented by the IAIS (International Association of Inflammation Societies) every two years to a man or women who has demonstrated scientific excellence and also has furthered the careers of woman in Inflammation science. Nominees must demonstrate significant scientific contributions in the field of Inflammation and have a substantial scientific reputation. 2013 will have been a fruitful year for Nathalie as on September 6, she was made a Chevalier de la Légion d’Honneur. All GREMI members are happy and proud and congratulate her for these national and international distinctions.


Last update December 2013

Eicosanoids

The classical features of inflammatory reactions are 1) an increase in blood flow, 2) an increase in vascular permeability with migration of cells into the tissue compartment, 3) the release of factors at the tissue sites and 4) resolution. These events are associated with a variety of locally released mediators which activate specific receptors. There is now considerable evidence to suggest that metabolites of the arachidonic acid cascade, namely, prostanoids, leukotrienes and lipoxins play a substantial role in the different phases of inflammation.

            The biological actions of arachidonic acid have essentially been attributed to the conversion of this substrate to a number of metabolites. The release of these lipid mediators varies considerably and depends to a large extent on the specific cell which is activated. Often several cells may interact to produce these lipid mediators by sharing the substrate and/or enzymes responsible for metabolite formation.

A series of enzymatic pathways, namely, cyclooxygenases (COX1, COX2) and lipoxygenases are responsible for the formation of numerous lipid mediators known as eicosanoids. The former enzymes are responsible for the formation of prostaglandins and thromboxane whereas the lipoxygenases transform arachidonic acid to the leukotrienes. The dual lipoxygenation of arachidonic acid by either the 15-lipoxygenase and the 5-lipoxygenase or the 12-lipoxygenase and the 5-lipoxygenase produce eicosanoids known as lipoxins. One of the oxoeicosanoids, the metabolite 5-oxo-6,8,11,14-eicosatetraenoic acid, which is derived from the activity of 5(S)-hydroxyeicosanoid dehydrogenase, has recently been shown to also be a potent mediator during inflammation. All of these endogenous lipid mediators are known to produce their biological effects by activation of specific cloned receptors.

            The evolution of eicosanoid receptors have now been phylogenically analyzed based on amino acid sequences. These receptors are located on a variety of cells, tissues, and organs and can be activated by either selective or non-selective ligands. Several of the receptors are known to play a role in different physiological conditions, for example: the control of the vascular tone. However, during chronic inflammation, such as, asthma, atherosclerosis, rheumatoid arthritis and gastrointestinal disease, their over-expression and role has yet to be fully elucidated. Of considerable interest are the number of compounds which have been developped and are known to selectively antagonized these receptors. In fact a few of the antagonists have been shown to be effective therapeutic agents.

 

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