Bacterial translocation contributes to cachexia and its possible pathway in patients with colon cancer

There is increasing evidence that bacterial translocation (BT) might contribute to the occurrence and development of cancer cachexia, but the detailed mechanism remains unknown. Thus, we undertook further investigations into the association of BT with cancer cachexia and the possible pathway.

The colon cancer patients enrolled in this study were divided into cachectic and noncachectic. BT was analyzed by polymerase chain reaction and bacterial culture. Intestinal epithelial T-cell subsets and NK cells were evaluated using flow cytometry. Western blotting and immunofluorescence were used to check tight junction (TJ) proteins in intestinal epithelium. Fluorescence in situ hybridization and immunohistochemistry were used to detect the translocated bacteria and endotoxin.

Compared with noncachectic patients, cachectic patients had a significantly higher BT ratio (P<0.001). We observed the translocated bacteria in the intestinal mucus layer associated with lower levels of T-cell subsets and NK cells in the intestinal epithelium in BT-positive patients (P<0.05). Endotoxin was detected within the small intestinal wall and the concentration of endotoxin decreased from the mucosal side to serosal side gradually in these patients. These were associated with an altered composition of TJs.

This study suggests that BT may contribute to colon cancer in cachectic patients, and TJ could be the gateway to the possible pathway of BT.