RESTOREGI Study: Regenerative Endoscopic Stromal Therapy: Outcomes and Risk Factor Evaluation in GI Fistulas

PROSPECTIVE RISK FACTOR ANALYSIS OF CLINICAL OUTCOMES FOLLOWING ENDOSCOPIC tSVF-em THERAPY FOR BENIGN GASTROINTESTINAL FISTULAS - RESTOREGI Study

RESTOREGI Study Benign gastrointestinal fistulas are abnormal communications between the gastrointestinal tract and adjacent organs or the skin. Chronic fistulas are often difficult to treat because of persistent inflammation, fibrosis, impaired vascularity, and defective tissue regeneration. Endoscopic regenerative therapy using mechanically processed autologous total stromal vascular fraction-enriched microfragmented adipose tissue (tSVF-EM) has emerged as a novel therapeutic approach that may promote tissue repair through angiogenesis, immunomodulation, and regenerative signaling.

Although early clinical experience suggests promising healing outcomes, factors predicting successful fistula closure remain poorly understood. The RESTOREGI study is a prospective, single-center observational cohort study designed to identify patient-related, fistula-related, and procedural factors associated with successful healing following endoscopic tSVF-EM therapy in benign gastrointestinal fistulas. The study will also evaluate treatment safety, time to healing, recurrence rates, and the impact of procedural variables on outcomes.

Benign gastrointestinal fistulas are abnormal communications between the gastrointestinal tract and adjacent organs or the skin that can result in significant morbidity, prolonged hospitalization, impaired quality of life, and repeated therapeutic interventions. Chronic fistulas are characterized by persistent inflammation, fibrosis, impaired perfusion, and defective tissue regeneration, all of which may contribute to failure of conventional closure techniques and recurrent disease.

Endoscopic regenerative therapy using autologous total stromal vascular fraction-enriched microfragmented adipose tissue (tSVF-EM) has emerged as a novel therapeutic approach for the management of complex gastrointestinal defects. Following adipose tissue harvest and mechanical processing, tSVF-EM contains a heterogeneous population of stromal and regenerative cells, extracellular matrix components, and bioactive factors that may promote angiogenesis, immunomodulation, tissue remodeling, and wound healing. Endoscopic delivery of this material directly into the fistula margins aims to create a biologically favorable environment for durable tissue repair.

Early clinical experience with regenerative endoscopic therapies has demonstrated technical feasibility and encouraging healing outcomes in selected patients with benign gastrointestinal fistulas. However, considerable variability in treatment response exists, and factors associated with successful healing remain poorly understood. Improved understanding of patient-related, fistula-related, and procedural determinants of treatment success may facilitate better patient selection, optimize procedural planning, guide the use of adjunctive therapies, and improve overall clinical outcomes.

The RESTOREGI study is a prospective, single-center, real-world cohort study designed to evaluate clinical outcomes following endoscopic tSVF-EM therapy in patients with benign gastrointestinal fistulas. Standardised data will be collected regarding patient characteristics, fistula anatomy and etiology, inflammatory and nutritional status, and procedural factors associated with regenerative endotherapy. The study is intended as an exploratory, hypothesis-generating investigation to identify clinically meaningful factors associated with fistula healing and to establish prospective safety and effectiveness data in this emerging field of regenerative endoscopy.

Findings from this study are expected to provide foundational evidence for future multicenter studies and contribute to the development of evidence-based patient selection and treatment strategies for regenerative management of benign gastrointestinal fistulas.

Inclusion Criteria:

• Age ≥18 years
• Confirmed benign gastrointestinal fistula involving the luminal gastrointestinal tract
• Fistula accessible for endoscopic evaluation and treatment
• Planned treatment with endoscopic tSVF-EM therapy, with or without adjunctive endoscopic therapies (argon plasma coagulation [APC], tract abrasion/curettage, clips, over-the-scope clips [OTSC], endoscopic suturing, or stent placement)
• Ability and willingness to provide written informed consent
• Willingness to comply with scheduled follow-up visits and study assessments

Exclusion Criteria:

• Perianal fistulas of any aetiology
• Inflammatory bowel disease-associated fistulas, including fistulas related to Crohn's disease or ulcerative colitis
• Malignancy-related fistulas
• Fistulas requiring primary oncologic surgical management
• Uncontrolled sepsis or undrained abscess at baseline (patients may become eligible following adequate drainage and clinical stabilisation)
• Contraindication to adipose tissue harvest, sedation, anaesthesia, or therapeutic endoscopy
• Pregnancy or lactation
• Severe coagulopathy not correctable prior to intervention
• Inability to provide informed consent
• Anticipated inability to complete study follow-up
• Participation in another interventional study that may influence fistula healing outcomes