Ulcerative Colitis in the Modern Era: Pathogenesis, Evolving Therapies and Future Directions

Ulcerative colitis (UC) is a chronic, idiopathic inflammatory bowel disease characterized by continuous mucosal inflammation of the colon, usually starting in the rectum. Its complex pathogenesis arises from genetic predisposition, immune dysregulation, epithelial barrier defects and gut microbiota imbalance. Clinically, UC presents with relapsing-remitting episodes of bloody diarrhea, abdominal pain, and rectal urgency. Diagnosis requires a comprehensive approach using clinical evaluation, endoscopy, histopathology and imaging. Treatment is guided by disease severity and extent. 5-aminosalicylic acid (5-ASA) agents such as mesalazine, olsalazine and balsalazide remain first-line options for mild to moderate UC. Corticosteroids are effective but unsuitable for long-term use due to adverse effects. Immunomodulators like azathioprine and methotrexate support maintenance therapy and enhance biologic durability. Biologics including anti-TNF therapies, anti-integrin antibodies and IL-12/23 inhibitors have transformed management of moderate to severe UC. New oral small molecules such as JAK inhibitors and S1P receptor modulators further expand available options. Emerging interventions like granulocyte-monocyte apheresis, fecal microbiota transplantation and microbiota-based therapies (probiotics, postbiotics, symbiotics) offer personalized approaches. The future of UC management lies in precision medicine, incorporating biomarkers, pharmacogenomics and individualized algorithms to optimize outcomes and improve patient quality of life.