Allogeneic Adipose Tissue-derived Mesenchymal Stem Cells for the Induction of Remission in Ulcerative Colitis

Inclusion Criteria: * Patients of either sex aged 18 years and older * Signed informed consent * Patients with ulcerative colitis diagnosed at least 6 months earlier in accordance with usual criteria * Left-sided colitis with moderate activity defined by a modified Truelove-Witts score between 11 and 21, and with no response to 4 weeks of treatment with oral and/or topical 5-aminosalicylates * Negative pregnancy test for women of childbearing potential (from menarche to menopause) using consistently and correctly highly effective (i.e. less than 1% failure rate per year) methods of birth control Exclusion Criteria: * Mental disability that impedes adequate understanding of the study and of the associated procedures * Extensive colitis * Patients with an impaired general state which requires, according to the investigator judgment, immediate treatment with corticosteroids and/or anti-Tumor Necrosis Factor (TNF) and/or surgery * Patients that fulfill criteria of corticodependency and in ongoing treatment with corticosteroids * Patients with previous colectomies * Known history of alcohol or other addictive substances abuse * History of malignant disease - Patients having participated in clinical trials with any investigational drug within 6 months prior to enrolment in this study * Patients with known allergies to penicillin, gentamicin, aminoglycosides, human serum albumin (HSA), Dulbecco's modified Eagle medium (DMEM), or materials of bovine origin * Pregnant or breastfeeding women * Presence of severe concomitant diseases * Patients with suspicion of Crohn?s enterocolitis, indeterminate colitis, ischaemic colitis, radiation colitis, diverticular disease associated colitis, or microscopic colitis