Inflammatory Bowel Disease (IBD), encompassing Ulcerative Colitis (UC) and Crohn's Disease (CD), significantly impairs patients' quality of life. Current monitoring of disease activity primarily relies on endoscopy combined with histological examination, which is associated with high costs, invasiveness, poor patient tolerance, and risks of complications. Additionally, disease activity indices and laboratory-based IBD staging metrics demonstrate limited utility and accuracy in clinical practice. This study aims to investigate the correlation between polyamine levels and their key enzymes in the polyamine metabolism pathway with IBD activity, thereby establishing a predictive model for IBD progression through polyamine and metabolite measurements; to estimate the efficacy of biologics via polyamine detection, providing a scientific basis for therapeutic selection; and to screen gut microbiota associated with polyamine metabolic alterations, offering evidence-based guidance for probiotic selection in IBD patients.

According to the inclusion and exclusion criteria, 91 patients with IBD diagnosed in the Department of Gastroenterology, the First Affiliated Hospital of Air Force Medical University from November 2024 to September 2025 were included, and the subjects were divided into remission group and active group according to the corresponding IBD scale scores; 46 healthy controls were generally included according to the number of patients; In addition, 47 patients in the first biologic treatment group were included according to the inclusion and exclusion criteria. The FFQ scale was used to calculate and evaluate the intake of polyamines in the enrolled patients, high performance liquid chromatography and mass spectrometry were used to measure the levels of polyamines in serum and fecal samples of patients, and immunohistochemical semi quantitative analysis of colon pathological sections was used to analyze the levels of key enzymes of polyamine metabolism.

Inclusion Criteria:

1. Age between 18 and 65 years;
2. Diagnosed with inflammatory (IBD) according to the Chinese Guidelines for the Diagnosis and Treatment of Ulcerative Colitis (2023, Xi'an) and the Chinese Guidelines for the Diagnosis and Treatment of Crohn's Disease (2023, Guangzhou);
3. Complete medical records available and written informed consent obtained from the participant.

Exclusion Criteria:

1. Presence of other metabolic disorders;
2. History of malignant tumors, severe organ dysfunction, or other severe systemic diseases affecting major organs, or hematological disorders;
3. Diagnosis of influenza, bacterial dysentery, or other infectious diseases within the past 2 weeks;
4. Presence of other diseases that may interfere with polyamine metabolism;
5. Use of antibiotics or probiotics within 8 weeks prior to the start of the study.

IBD patients aged 18-65 years were recruited from The First Affiliated Hospital of the Air Forth Medical University.