The study is focused on evaluating the safety and efficacy of using vascular stromal tissue, derived from autologous adipose tissue, and subjected to microfragmentation and emulsification (Stromal Vascular Fraction Micro-Emulsion - tSVFem), in the treatment of chronic gastrointestinal fistulae (CGF). Tissue regeneration will be stimulated using 3D bio-printed scaffolds, enriched at implantation with mesenchymal stem cells derived from patients' adipose tissue; injection of tSVFem and scaffold placement will be performed endoscopically. The study proposes to use 3D bioprinting to create customized polymeric bioinks (gels) on supporting scaffolds that can serve as a framework for the growth and development of the patient's cells. This approach aims to promote tissue regeneration and integration, repair extensive CGF and restore the proper microbiota.

A small portion of the patient's tSVFem will be injected in a bioreactor into the scaffolds and used for evaluation of the ability of the scaffolds to support cell proliferation, migration, and differentiation, as well as secretion of cytokines and growth factors and the immunological response. Also, to analyze the effect on cells and microbial species, the intestinal microbiota will be analyzed in a bioreactor under different dynamic conditions on the growth and differentiation of the MSCs contained in tsVFem, on the bio-printed scaffolds and the immunological results.

Inclusion Criteria:

• patients with CGF at any level that can be approached endoscopically and for whom the possibility of conventional conservative treatment is ruled out, or all possible conservative or surgical treatments have already been performed without benefit, or in whom the reiteration of such treatments is contraindicated, because of life-threatening, and/or possible complications, and/or disabling outcomes.

Exclusion Criteria:

• patients who have not given informed consent to the procedure;
• patients with entero-enteral CGF,
• patients who have therapeutic options of other type.