Accurately Profiling the Changes and Functions of Key Microflora in the Whole Intestinal Microenvironment Based on the Visual Sampling Capsule Endoscopy in Patients With Inflammatory Bowel Disease

Inclusion Criteria

General Inclusion Criteria:

1. Male or female, aged 18 years or older and 80 years or younger;
2. Willing and able to complete the study assessments, including repeated capsule endoscopy examinations and daily records of diet, activity, and defecation;
3. Willing to provide fecal (stool), saliva, and intestinal fluid samples and to consent to long-term storage of the provided samples for research purposes;
4. Willing to avoid vigorous physical activity during participation in this clinical trial;
5. Willing to participate in this clinical trial and to sign the informed consent form.

Inclusion Criteria for Patients with Ulcerative Colitis (UC):

1. Confirmed diagnosis of ulcerative colitis (UC) for at least 3 months during the screening period (Day -14 to 0), confirmed by endoscopic and histological evidence, with a histopathology report (if no report is available, endoscopy and histological examination may be performed at screening);
2. Diagnosis established by at least one of the following clinically accepted methods: endoscopy (e.g., colonoscopy) showing typical UC manifestations; histopathological examination consistent with UC features; imaging studies (e.g., CTE, MRE) showing typical UC changes; or comprehensive assessment by a digestive specialist based on clinical presentation, laboratory tests (e.g., fecal calprotectin, inflammatory markers), and exclusion of infectious enteropathy.

Inclusion Criteria for Patients with Crohn's Disease (CD):

1\. Confirmed diagnosis of Crohn's disease (CD) by at least one of the following clinically accepted methods: endoscopy (e.g., colonoscopy) showing typical CD manifestations; histopathological examination consistent with CD features; imaging studies (e.g., CTE, MRE) showing typical CD changes; or comprehensive assessment by a digestive specialist based on clinical presentation, laboratory tests, and exclusion of infectious enteropathy.

Inclusion Criteria for Healthy Subjects:

1. No chronic gastrointestinal symptoms (e.g., abdominal pain, diarrhea, constipation, hematochezia, bloating);
2. No history of inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), celiac disease, or other chronic gastrointestinal disorders;
3. A normal colonoscopy within the past year, or a negative fecal occult blood test with no related symptoms if colonoscopy has not been performed.

If any of the above items is answered "No", the subject cannot enter the study.

Exclusion Criteria:

1. Other gastrointestinal diseases, including gastrointestinal cancer, indeterminate colitis, infectious colitis or colitis with a definite etiology, and toxic megacolon (for the UC cohort, Crohn's disease is also excluded; for the CD cohort, ulcerative colitis is also excluded);
2. Known or suspected gastrointestinal obstruction, stricture, diverticulum, fistula, or perforation;
3. Severe cardiac, pulmonary, or renal insufficiency, liver cirrhosis, hepatic insufficiency, or hematologic diseases;
4. Known or suspected malignant tumors, acute severe illness, or other end-stage diseases, or concomitant diseases with an expected survival of less than 12 months;
5. Any active infection caused by bacteria, viruses, fungi, or other pathogens, or recurrent or chronic infection;
6. Receipt of anti-infective treatment (including antibacterial, antifungal, or antiviral agents) within 3 months before enrollment;
7. Other medications (to be specified);
8. Inability to undergo or refusal to undergo any abdominal surgery (capsule retention cannot be surgically managed);
9. Planned magnetic resonance imaging (MRI) before the capsule endoscope is excreted;
10. Dysphagia;
11. Pregnant or lactating women;
12. Poor general condition and inability to tolerate sampling capsule endoscopy;
13. Any form of active substance abuse or dependence (including drug or alcohol abuse), any unstable physical or mental illness, or any chronic condition that the investigator considers may interfere with the conduct of the study;
14. Participation in another clinical trial within three months, or current participation in another clinical trial;
15. Any other factors that the investigator considers unsuitable for enrollment or that may affect the participant's participation in the study.