Anorectal Transplantation: The First Long-term Success in a Canine Model

Microsurgical Technique and Results of Anorectal Transplantation in the Rat

Anorectal transplantation (ART) is an obvious therapeutic option for treating permanent colostomy and severe fecal incontinence. The rat is the best model for beginning studies of a new surgical procedure. In this article, we review ART techniques in rats.

METHODS

We reviewed articles on rat and ART keywords throughout Cochrane Library, MEDLINE, and EMBASE. Five articles were found, of which 2 used autotransplantations, 1 performed only transplantation of the anal canal and extraperitoneal rectum, and another performed transplantation of the entire intestine, including the anus, but only followed for 2 hours.

RESULTS

In 2016, we performed the first series of isoART (n = 6) and alloART (n = 9) of the entire anorectal segment and micro-anastomosis of the inferior mesenteric vessels. Two animals died due to surgical complications, and the others survived until the endpoint of the experiment. Five animals with alloART showed clinical signs of immunologic rejection 3 weeks after transplantation, and autopsy histology on postoperative day 30 revealed moderate to severe rejection in the allografts.

CONCLUSIONS

In this review, we observed that ART in rats is viable and may allow further physiologic and immunologic studies of this procedure, a potential treatment for severe incontinence and permanent colostomy.

Cell Therapy for Anal Sphincter Incontinence: Where Do We Stand?

Anal sphincter incontinence is a chronic disease, which dramatically impairs quality of life and induces high costs for the society. Surgery, considered as the best curative option, shows a disappointing success rate. Stem/progenitor cell therapy is pledging, for anal sphincter incontinence, a substitute to surgery with higher efficacy. However, the published literature is disparate. Our aim was to perform a review on the development of cell therapy for anal sphincter incontinence with critical analyses of its pitfalls. Animal models for anal sphincter incontinence were varied and tried to reproduce distinct clinical situations (acute injury or healed injury with or without surgical reconstruction) but were limited by anatomical considerations. Cell preparations used for treatment, originated, in order of frequency, from skeletal muscle, bone marrow or fat tissue. The characterization of these preparations was often incomplete and stemness not always addressed. Despite a lack of understanding of sphincter healing processes and the exact mechanism of action of cell preparations, this treatment was evaluated in 83 incontinent patients, reporting encouraging results. However, further development is necessary to establish the correct indications, to determine the most-suited cell type, to standardize the cell preparation method and to validate the route and number of cell delivery.