New Delhi: A new study has uncovered how chronic stress can exacerbate the progression of colorectal cancer (CRC) by disrupting the gut microbiota. This finding could open new avenues for treatment. Conducted by researchers at Sichuan University’s West China Hospital, the study shows that stress diminishes beneficial bacteria in the gut, particularly the Lactobacillus genus, which plays a critical role in the body’s immune defense against cancer.
Chronic stress has long been associated with a variety of health issues, but its specific impact on CRC has not been fully understood until now. The researchers used an antibiotic cocktail—comprising vancomycin, ampicillin, neomycin, and metronidazole—to eliminate gut bacteria in mice. They followed this with fecal microbiota transplantation to investigate whether gut bacteria are necessary for chronic stress to accelerate the progression of CRC.
The results showed that stress not only led to faster tumor growth but also significantly reduced levels of Lactobacillus, a type of bacteria essential for maintaining a healthy immune response. This depletion weakened the activity of CD8+ T cells, which are key to the body’s anti-tumor immunity. CD8+ T cells play a vital role in identifying and destroying cancer cells, and their reduced function under stress conditions provided a clear link between gut bacteria, stress, and tumor growth.
To further explore this connection, the researchers supplemented mice undergoing chronic stress with Lactobacillus. Remarkably, this intervention reduced tumor formation, indicating that restoring beneficial bacteria in the gut could help counteract the negative effects of stress on CRC progression. In particular, the team found that Lactobacillus plantarum (L. plantarum) regulated bile acid metabolism and boosted the function of CD8+ T cells, which in turn enhanced the body’s natural defense against cancer.
Dr. Qing Li, the lead researcher, highlighted the potential therapeutic implications of these findings. “Restoring beneficial bacteria in the gut, such as Lactobacillus, could strengthen the body’s natural defenses against colorectal cancer,” he said. The study suggests that Lactobacillus-based therapies could be particularly beneficial for CRC patients experiencing chronic stress.
The findings, presented at the 2024 United European Gastroenterology Week in Vienna, Austria, underscore the growing understanding of the gut microbiota’s influence on cancer progression and stress-related health issues. This research points to potential new treatment strategies that focus on restoring the balance of gut bacteria to support anti-tumor immunity.