• Permissive microbiome characterizes human subjects with a neurovascular disease cavernous angioma | Nature Communications
    https://www.nature.com/articles/s41467-020-16436-w

    Cavernous angiomas (CA) are common vascular anomalies causing brain hemorrhage. Based on mouse studies, roles of gram-negative bacteria and altered intestinal homeostasis have been implicated in CA pathogenesis, and pilot study had suggested potential microbiome differences between non-CA and CA individuals based on 16S rRNA gene sequencing. We here assess microbiome differences in a larger cohort of human subjects with and without CA, and among subjects with different clinical features, and conduct more definitive microbial analyses using metagenomic shotgun sequencing. Relative abundance of distinct bacterial species in CA patients is shown, consistent with postulated permissive microbiome driving CA lesion genesis via lipopolysaccharide signaling, in humans as in mice. Other microbiome differences are related to CA clinical behavior. Weighted combinations of microbiome signatures and plasma inflammatory biomarkers enhance associations with disease severity and hemorrhage. This is the first demonstration of a sensitive and specific diagnostic microbiome in a human neurovascular disease.

    AXE #INTESTIN-#CERVEAU : Désordre intestinal et hémorragie cérébrale ? | santé log
    https://www.santelog.com/actualites/axe-intestin-cerveau-desordre-intestinal-et-hemorragie-cerebrale

    C’est une « drôle » d’association, découverte par cette équipe de l’Université de Chicago : les patients atteints d’une maladie cérébrale hémorragique [angiome caverneux, héréditaire ou non] présentent aussi des #microbiomes intestinaux très désordonnés.

    [..,]

    En substance, l’analyse identifie [dans les selles de] ces patients une communauté bactérienne « très perturbée » : « Les patients atteints d’angiome [caverneux] cérébral présentent tous le même microbiome distinctif, qu’ils aient hérité de la mutation ou qu’ils aient développé une lésion sporadique. Ce déséquilibre bactérien produit des molécules de lipopolysaccharides (LPS), qui voyagent via le sang vers le cerveau et se fixent à la paroi des vaisseaux sanguins du cerveau, entraînant le développement de lésions »

    Le #microbiome est une cause de lésions plutôt qu’un effet, concluent les chercheurs.

  • How Burgers and Fries Are Killing Your Microbial Balance
    http://nautil.us/issue/30/identity/how-the-western-diet-has-derailed-our-evolution

    So a remarkable and somewhat quixotic effort has begun to catalog and possibly preserve, before they disappear, the #microbes of people who live in environments thought to resemble humanity’s past—people whose #microbiomes may approximate an ancestral state. Researchers are motoring down rivers in the Amazon, off-roading in the East African savanna, hiking into the mountain villages of Papua New Guinea. They see themselves as rushing to catalog an ecosystem that may soon disappear.

    “It’s really our last chance to harvest a lot of these microbes from around the world,” Rob Knight, a microbiologist at the University of California, San Diego, told me. “We have to do it before it’s too late—and it’s very nearly too late.”

    He and others suspect these populations won’t retain their traditional ways much longer. Antibiotics, thought to deplete microbes, are already used frequently in some communities. And as modernization and acculturation progresses—as these peoples move toward the sanitized, indoor-dwelling, junk food-eating reality that characterizes much life in developed nations today—some human microbes, or perhaps certain configurations of those microbes, may be lost forever.

    For now, scientists are careful to characterize the quest as purely descriptive; they want to know how these human microbiomes affect our bodies. Yet a kind of microbial ark—a storage vault for potentially endangered human microbes—is perhaps implied. Martin Blaser, a microbiologist at New York University and Dominguez-Bello’s husband, argues that because Westernized peoples may have lost important microbes, we may have to repopulate ourselves with microbes derived from more traditional-living populations—from, say, Amazonian Amerindians or African hunter-gatherers.

    #microbiote #alimentation