EPAS1 and serum lipopolysaccharide activity: In experimental models, HIF1α plays an important role in the bactericidal capacity of macrophages to prevent systemic spreading of an infection (45–47), and conditional knock-out of HIF1α or HIF2α in myeloid cells protects mice against LPS-induced endotoxemia by reducing the pro-inflammatory cytokine production, hypothermia, and hypotension (35–37).