The human gut is more than a long tube for digesting food – it is one of our body’s largest and busiest borders, constantly deciding what may enter and what must stay out. Most of these decisions are made by a nervous system embedded within the gut wall, often called ‘the brain in the gut’, and supported by the local immune system. When this border becomes too permeable, often described as a ‘leaky gut’, problems can arise throughout the body. Researchers Vedrana Bali and Vladimir Grubišić, at the New York Institute of Technology College of Osteopathic Medicine, argue that this leaky-gut phenomenon may cause far more than stomach troubles. Read More
They highlight growing evidence that increased gut permeability can contribute to metabolic conditions, autoimmune diseases, and even disorders affecting the brain, including anxiety, depression, and neurodegeneration. Their recent work sheds light on an overlooked player in keeping this barrier intact: enteric glial cells.
Enteric glia are sometimes compared to the brain’s support cells. Once thought to be passive support cells, glia are now recognized as powerful regulators of gut health nestled alongside intestinal nerves and directly touching the cells that form the gut. This puts them in a perfect position to sense and integrate signals from neurons, immune cells, and the gut lining.
Bali and Grubišić explain how glia detect chemical changes in their environment and translate this information into actions that can strengthen or weaken the intestinal barrier. When glia are activated, they can directly influence how tightly the cells of the gut lining are sealed, how ions and fluids move across the tissue, and how immune cells behave in the neighbourhood.
The researchers emphasise that the condition of the barrier becomes especially important during inflammation. In inflammatory bowel disease, for instance, persistent gut barrier ‘leakiness’ can continue even when symptoms quieten down, increasing the likelihood of future flare-ups.
The researchers describe evidence that glia can play almost contradictory roles here. In some situations, they help repair damage by breaking down inflammatory signals, preventing further injury. In other cases, glia can inadvertently worsen barrier problems through activation of adenosine 2B receptors and promote further dysfunction. This dual nature – protector in some contexts, aggravator in others – is why the researchers playfully call glia both ‘friends and foes’.
Their paper also touches on the gut–brain connection. Because glia sit at the crossroads of nerves, hormones, and immune cells, they may help explain why disturbances in the gut barrier can ripple outward to affect mood, cognition, and behaviour. Research already shows changes in enteric glia in conditions like Parkinson’s disease and stress-related disorders.
For Bali and Grubišić, the takeaway is clear: a healthy gut barrier matters for whole-body health, and enteric glia are key regulators of that barrier. Understanding how to guide these glial cells toward their protective roles could eventually open the door to new treatments for a wide range of gut-related and even brain-related conditions.
