Var_dump

$sql = 'SELECT *
            FROM articles as art
            LEFT JOIN articles_focus as artf ON artf.articles_id=art.id
            LEFT JOIN articles_themes as artt ON artt.articles_id=art.id
            LEFT JOIN themes ON artt.themes_id=themes.id
            LEFT JOIN focus ON artf.focus_id=focus.id 
            WHERE art.id=4888  ';   
$req = $pdo->query($sql);
$req->setFetchMode(PDO::FETCH_OBJ);

while($donnees=$req->fetch()){
  
    echo $donnees-> titre. ' <br/>' ;

}

var_dump($donnees-> titre);