HSPA1A and serum lipopolysaccharide activity: The present study determined: (1) the basal levels of Klotho and HSP70 in aging mouse heart and the effect of endotoxemia on their levels, (2) whether augmented inflammatory responses and more severe cardiac dysfunction in aging endotoxemic mice are associated with relative Klotho deficiency, (3) the relationship between Klotho and HSP70 during endotoxemia in aging mice and (4) the therapeutic potential of recombinant Klotho for amelioration of aging-related inflammation and cardiac dysfunction.