TNF and obesity due to melanocortin 4 receptor deficiency: The results of a 1-year follow-up study on obesity patients with prediabetes indicated that metformin could obviously reduce the levels of inflammation markers, such as IL-6, C Reactive Protein (CRP), TNF-α, and nitrotyrosine, as well as inflammation-correlated microRNAs (miRs) such as miR 195 and miR 27 (44).