For some time now, we’ve known of a connection between the brain and the gut. Known as the gut-brain axis , it shows that what happens in the brain can directly affect the gastrointestinal system, and vice versa. Recent research has shown this connection also extends to the gut microbiome , immune system , and endocrine system . Past studies show that certain mental health conditions, such as depression, anxiety, and psychological stress, can negatively impact the gut-brain axis. Now, a new study published in the journal Cell Stem Cell says there is also a gut-brain-bone marrow connection. In this interconnection, psychological stress may alter the gut microbiome, potentially accelerating the aging process in bone marrow stem cells , as shown in a mouse model. For this study, researchers used an animal model of psychological stress to examine how it might interact with the brain, intestines , and bone marrow.
For some time now, we’ve known of a connection between the brain and the gut. Known as the gut-brain axis , it shows that what happens in the brain can directly affect the gastrointestinal system, and vice versa.
Recent research has shown this connection also extends to the gut microbiome , immune system , and endocrine system .
Past studies show that certain mental health conditions, such as depression, anxiety, and psychological stress, can negatively impact the gut-brain axis.
Now, a new study published in the journal Cell Stem Cell says there is also a gut-brain-bone marrow connection. In this interconnection, psychological stress may alter the gut microbiome, potentially accelerating the aging process in bone marrow stem cells , as shown in a mouse model.
For this study, researchers used an animal model of psychological stress to examine how it might interact with the brain, intestines , and bone marrow.
“Many people have experienced becoming more susceptible to colds or other illnesses during periods of prolonged psychological stress,” Meng Zhao, PhD , professor and doctoral supervisor in the Zhongshan School of Medicine at Sun Yat-sen University in China, and senior author of this study, told Medical News Today .
“This common experience led us to ask whether psychological stress suppresses immunity by affecting hematopoietic stem cells (HSCs) , which generate the entire blood and immune system,” he said.
“Psychological stress is increasingly recognized as an important risk factor for many diseases, including cancer, cardiovascular disease, and age-related disorders. However, we still know relatively little about how emotional stress is translated into biological signals that affect distant organs.” — Meng Zhao, PhD
At the study’s conclusion, Zhao said he and his team found that stress impaired HSC self-renewal and reduced the production of lymphocytes , a type of white blood cell.
While investigating the underlying mechanism, they unexpectedly discovered that the brain communicates with the bone marrow through sympathetic regulation of the intestinal environment and gut microbiota, ultimately altering microbiota-derived spermidine — naturally occurring organic molecules believed to promote healthy aging — and HSC function.
“When the brain experiences psychological stress, it sends signals through the sympathetic nervous system to the intestine,” Zhao detailed. “These signals alter the intestinal environment and the gut microbiota, reducing the availability of beneficial metabolites such as spermidine. Without sufficient spermidine, HSC gradually lose their ability to maintain healthy blood and immune cell production.”
“In other words, emotional stress in the brain can indirectly influence the body’s immune system through the gut. Because spermidine is a metabolite with broad biological functions, this mechanism may also influence other organs beyond the bone marrow.” — Meng Zhao, PhD
Scientists also discovered that chronic stress reduced activity in two brain areas — the medial prefrontal cortex and the periaqueductal gray .
“To our knowledge, this is the first direct functional evidence that specific brain regions regulate HSC function in the bone marrow,” Zhao said. “We found that suppressing these two stress-responsive brain regions was sufficient to reproduce many of the hematopoietic and immune defects caused by psychological stress.”
“These findings demonstrate that specific neural circuits actively regulate immune stem cell function rather than simply responding to stress. More importantly, identifying these brain regions provides potential targets for developing new strategies to preserve immune function under chronic psychological stress.” — Meng Zhao, PhD
“Our next goal is to determine whether this brain–gut–bone marrow axis operates similarly in humans and whether it contributes to immune dysfunction in aging, cancer, and other chronic diseases,” Zhao added.
MNT spoke with Ashkan Farhadi, MD , a board certified gastroenterologist at MemorialCare Orange Coast Medical Center in Fountain Valley, CA, about this study, who commented it adds one more layer to our understanding about the role of stress and the whole body.
“We had some understanding regarding the brain-gut axis that we knew there is a strong bi-directional current connection between the brain and gut,” Farhadi, who was not involved in this study, explained. “This access has been recently extended into brain-gut microbiome access. And now we’re having this access extended into other organs, including bone marrow and the general health of the body.”