In this experimental study, researchers investigated how H. pylori infection influences depression-like behavior and certain biological markers in mice, focusing especially on the hormone ghrelin.
Mice infected with the bacteria showed more anxiety- and depression-like behaviors in standard laboratory tests compared with healthy mice. They moved less, showed more signs of stress, and had lower preference for sweet solutions, a common indicator of loss of pleasure.
Biologically, H. pylori infection led to reduced circulating ghrelin levels and activation of the mTOR signaling pathway in the stomach. It was also associated with increased markers of brain inflammation and cell injury in the hippocampus, a brain region important for mood regulation. When mice were treated with rapamycin, an mTOR inhibitor, ghrelin levels increased and brain-inflammation markers were reduced.
Overall, the study suggests that H. pylori infection may contribute to anxiety- and depression-like behaviors by lowering ghrelin levels and increasing neuroinflammation, highlighting a potential biological link between gut infection and mental health.
Learn more about this study here: https://doi.org/10.1155/2022/2847672
Reference
Tian, Jiageng, Wang, Zeyu, Ren, Yadi, Jiang, Yong, Zhao, Ying, Li, Man, Zhang, Zhiguang, Rapamycin Attenuates Anxiety and Depressive Behavior Induced by Helicobacter pylori in Association with Reduced Circulating Levels of Ghrelin, Neural Plasticity, 2022, 2847672, 8 pages, 2022.