This "vampire" study reveals the limitations of common methods for diagnosing Crohn's disease and other diseases. This method needs to find a protein associated with intestinal inflammation in human feces. However, although this kind of protein, called calprotectin, does appear in cases of intestinal inflammation, it may also be a sign of simple gastrointestinal (GI) bleeding, and this difference is difficult to make. The researchers reported in the August issue of the European Joint Journal of Gastroenterology that this protein is still a good disease marker, said Dr. Stephen Wafrika, a gastroenterologist and the lead author of the study and director of the Center for Gastroenterology and Liver Diseases in Zurich. Face up to the health of your digestive system bravely
However, doctors should be aware that under special circumstances, high levels of calcineurin may be a sign of bleeding, not inflammation, Vavricka told Life Science:
Inflammatory inflammatory bowel disease (IBD)- including Crohn's disease and ulcerative colitis-is difficult to diagnose and treat, partly because intestinal inflammation is not always accompanied by patients' symptoms. For example, Vavrika and his colleagues wrote in their new paper that a person may continue to have symptoms such as diarrhea after intestinal inflammation basically disappears, and the severity of symptoms is naturally subjective.
Similarly, inflammation is not always accompanied by symptoms. Because of arthritis or other diseases such as simple virus infection, patients may show high immune activity. This is why endoscopy-an examination in which a long tube and a camera are inserted into the human intestine-is the best way to measure someone's inflammatory bowel disease activity.
But endoscopy is an invasive and uncomfortable process, so doctors often evaluate patients' diseases through stool samples. One of the main protein examined by doctors is calcineurin, which exists in immune cells called neutrophils. In a series of inflammatory processes, neutrophils flood into intestinal mucosa in large quantities.
Vavricka said that the problem is that neutrophils also exist in the blood. Therefore, if the patient has upper gastrointestinal bleeding-a common symptom of ——IBD-neutrophils, then calcium protectant will appear in stool samples. This confuses the question of whether this person is experiencing an inflammatory outbreak. According to the Mayo Clinic, the upper digestive tract refers to the upper part of the esophagus, stomach and small intestine. )
"Before we did this study, we were not sure how much blood would enter the intestine before your calcium protectant level was positive," said Wafrika.
The study "Drinking Blood for Science" found that Wafrika and his colleague Jean 16 healthy volunteers drank 3 ounces (100 ml) or 10 ounces (300 ml) of blood. Most of these volunteers were medical students at Triem Li Hospital in Zurich. A month later, the person who took the 3-ounce dose swallowed the 10-ounce dose again, and vice versa. For reference, American Airlines passengers can carry 3.4 ounces of liquid in containers on the plane. ) 7 human beings behave strangely like vampires.
Among the 12 women and 4 men who participated in the study, most of them only drank blood, although a few people chose nasogastric tubes to deliver blood directly to their stomachs. About half of the subjects complained about stomach discomfort, such as nausea, and one third to one quarter said they had diarrhea or constipation after eating.
All subjects noticed that their feces became extremely dark after drinking blood, which is a well-known side effect of blood in the digestive system. Participants were given fecal samples of G blood two days before drinking, once a day for the next seven days, and once again 14 days after drinking.
The researchers found that the level of calcium protectant in feces increased after blood intake. After a dose of 3 ounces, 46% of the fecal samples showed calcium protectant higher than 50 micrograms per gram, which means that half of the samples showed an increase in calcium protectant at some point. After taking the dose of 10 ounce, 63% of the samples increased at some point.
The researchers did not see the level as high as 200 μ g/g, which may exist in the onset of inflammatory bowel disease. This means that doctors need to consider the level of calcium protectant according to the specific situation, Vavrika said. A very high level may mean the diagnosis of IBD.
At a low level, other factors should be considered before diagnosing IBD. Vavricka said that patients with risk factors for upper gastrointestinal bleeding, such as high blood pressure or taking a lot of non-steroidal anti-inflammatory drugs such as aspirin, are likely to have higher levels due to bleeding. On the other hand, if the level of calcineurin increases, patients with massive abdominal pain or family history of IBD may indeed have inflammatory reaction.
Originally published in the journal Life Science.