Recent research has revealed a significant connection between gut aging and an increased risk of colon cancer. A study published in Nature Aging highlights how epigenetic changes in stem cells of the human gut can lead to altered gene expression, ultimately compromising the gut’s ability to repair itself. This international effort, led by Prof. Francesco Neri from the University of Turin in Italy, identifies a process termed ACCA (Aging- and Colon Cancer-Associated) drift, which intensifies with age.
The human gut is unique in its ability to replace cells rapidly; this renewal occurs every few days through specialized stem cells that maintain the integrity of the intestinal lining. However, as these stem cells age, they accumulate epigenetic modifications—chemical alterations that influence gene activity. Prof. Neri notes, “We observe an epigenetic pattern that becomes increasingly apparent with age,” indicating that these changes follow a systematic progression rather than occurring randomly.
Aging Patterns Linked to Cancer Risk
The study found that genes most affected by ACCA drift are crucial for maintaining normal tissue function, particularly those involved in the Wnt signaling pathway, which is essential for renewing the intestinal lining. Disruption in these genes diminishes the gut’s self-repair capabilities. The research team discovered that the same epigenetic patterns observed in aging tissues were prevalent in nearly all colon cancer samples analyzed. This overlap raises concerns that aging stem cells may create an environment conducive to cancer progression.
Another striking aspect of the findings is the uneven effect of aging on the intestine. The gut comprises numerous tiny structures known as crypts, each originating from a single stem cell. If a stem cell undergoes epigenetic changes, all cells within that crypt inherit these modifications. Dr. Anna Krepelova explains this phenomenon: “Over time, more and more areas with an older epigenetic profile develop in the tissue.” This division process leads to a patchwork of younger and older crypts, resulting in some regions being healthier while others become more susceptible to producing damaged cells, thereby increasing cancer risk.
Iron Imbalance and Inflammation Accelerate Aging
The research also uncovers the underlying mechanisms driving epigenetic drift. Aging intestinal cells tend to absorb less iron while excreting more, which decreases the availability of iron (II) in the cell nucleus. This iron is vital for the function of TET (ten-eleven translocation) enzymes, responsible for eliminating excess DNA methylations. As iron levels drop, these enzymes become less effective, leading to a buildup of harmful DNA markings. Dr. Krepelova states, “When there’s not enough iron in the cells, faulty markings remain on the DNA,” resulting in key genes becoming inactive.
Additionally, age-related inflammation exacerbates these issues. The research team demonstrated that even mild inflammatory signals can disrupt cellular iron balance and stress metabolism. Concurrently, Wnt signaling diminishes, impairing the activity and health of stem cells. The interplay of iron deficiency, inflammation, and weakened Wnt signaling accelerates epigenetic drift, suggesting that intestinal aging may progress more rapidly than previously understood.
Despite the intricate nature of these processes, the researchers suggest that there may be potential for intervention. In laboratory settings using organoid cultures—miniature models of the intestine derived from stem cells—scientists successfully slowed or partially reversed epigenetic drift. By enhancing iron uptake or directly stimulating Wnt signaling, they were able to reactivate TET enzymes and enable cells to clear excess DNA methylations. Dr. Krepelova concludes, “This means that epigenetic aging does not have to be a fixed, final state.” This groundbreaking research opens the door to new strategies for addressing gut aging and its associated cancer risks.
