TNF and Parkinson disease: To further investigate the molecular interactions between gut microbial dysbiosis and gut inflammation in PD, we determined colon levels of tumor necrosis factor‐α (TNF‐α), interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6), and inducible nitric oxide synthase (iNOS) by quantitative real‐time polymerase chain reaction (qRT‐PCR) and western blot.