TNF and asthma: Metformin has been shown to inhibit autoreactive and proinflammatory cells and to restore immune homeostasis [126], as well as to reduce IL-6, TNFα and intracellular adhesion molecule-1 (ICAM-1) in women with polycystic ovary syndrome [127], and to lower asthma-related hospitalization and asthma exacerbation in diabetic patients [128].