Stem cell therapy for Crohn's disease: systematic review and meta-analysis of preclinical and clinical studies

Background We explored whether stem cell therapy was effective for animal models and patients with Crohn's disease (CD). Methods We searched five online databases. The relative outcomes were analyzed with the aid of GetData Graph Digitizer 2.26 and Stata 16.0 software. The SYRCLE risk of bias tool and the MINORS tool were used to assess study quality. Results We evaluated 46 studies including 28 animal works (n = 567) and 18 human trials (n = 360). In the animal studies, the disease activity index dramatically decreased in the mesenchymal stem cell (MSC) treatment groups compared to the control group. Rats and mice receiving MSCs exhibited longer colons [mice: standardized mean difference (SMD) 2.84, P = 0.000; rats: SMD 1.44, P = 0.029], lower histopathological scores (mice: SMD - 4.58, p = 0.000; rats: SMD - 1.41, P = 0.000) and lower myeloperoxidase levels (SMD - 6.22, P = 0.000). In clinical trials, stem cell transplantation reduced the CD activity index (SMD - 2.10, P = 0.000), the CD endoscopic index of severity (SMD - 3.40, P = 0.000) and simplified endoscopy score for CD (SMD - 1.71, P = 0.000) and improved the inflammatory bowel disease questionnaire score (SMD 1.33, P = 0.305) compared to control values. CD patients maintained high remission rates for 3-24 months after transplantation. Conclusions Stem cell transplantation is a valuable supplementary therapy for CD.