Bridge of imbalance: How does the brain-gut axis act as a catalyst for gastrointestinal tumors in aging

Figure 5 Disruption of circadian rhythms and gastrointestinal tumors. The aging process induces the aberrant expression of core biological clock genes (Per/Clock/Bmal1), resulting in disrupted circadian rhythm regulation and consequent abnormalities in lipid metabolism in the liver, diminished intestinal barrier function, and immunosuppression within the tumor microenvironment. At the molecular level, this is evidenced by abnormal H3K4me1 histone modifications, activation of oncogenes, and suppression of DNA repair mechanisms. MDSCs: Myeloid-derived suppressor cells; Treg: Regulatory T cell.