Could an imbalanced gut cause liver failure, lung injury, or pancreatitis in patients in intensive care? Though such events have historically been viewed in isolation, the importance of a properly functioning gut to overall well-being is becoming clearer. In a recent literature review, an international research team concluded that gastrointestinal failure is a potential cause of death in the critically ill – even in those without diseases originating from the gut.
The gut’s crucial role in well-being hinges on its ability to absorb nutrients from food while also preventing harmful agents from entering the bloodstream. The specialized cells that line the gut and the community of microorganisms living therein are key to maintaining this harmony. Major trauma, surgery, or critical illness can weaken the gut barrier and disturb the delicate balance of microbes, leaking gut contents into other parts of the body and allowing pathogens to take hold.
The contents of the gut enter the circulation through the liver and lymphatic vessels. The liver usually acts as a gatekeeper to the gut, preventing the escape of pathogens. In patients with liver disease, this function is lost, which allows the spread of potentially fatal infections. The cells lining the gut also produce inflammatory compounds that can pass through the lymphatic vessels lining the intestines. Experiments with mice have revealed that these toxic molecules travel this path to the lungs, creating dangerous inflammation and organ damage.
In addition to the gut’s capacity to damage other organs, diseases originating outside the gastrointestinal tract can injure the gut. Patients with severe pancreatitis secrete high levels of pancreatic enzymes that destroy the gut barrier. This destruction aggravates the original disease, which in turn further degrades the gut, generating a vicious feedback loop.
Fortunately, as understanding of the complex relationship between the gut and overall well-being improves, new methods for restoring inflammatory balance can potentially reduce the widespread damage of a failed gastrointestinal system -- and ultimately save the lives of patients in intensive care.