A potential anatomic subtype of short bowel syndrome: a matched case-control study

Small bowel transplant - novel indications and recent progress

INTRODUCTION

Advances in the management of intestinal failure have led to a reduction in the number of intestinal transplants. The number of bowel transplants has been mainly stable even though a slight increase has been observed in the last 5 years.

AREAS COVERED

Standard indication includes patients with a reasonable life expectancy. Recent progress can be deduced by the increased number of intestine transplants in adults: this is due to the continuous improvement of 1-year graft survival worldwide (without differences in 3- and 5-year) associated with better abdominal wall closure techniques. This review aims to provide an update on new indications and changes in trends of pediatric and adult intestine transplantation. This analysis, which stretches through the past 5 years, is based on a collection of related manuscripts from PubMed.

EXPERT COMMENTARY

Intestinal transplants should be solely intended for a group of individuals for whom indications for transplantation are clear and both medical and surgical rehabilitations have failed. Nevertheless, many protocols developed over the years have not yet solved the key question represented by the over-immunosuppression. Novel indications and recent progress in the bowel transplant field, minimal yet consistent, represent a pathway to be followed.

Generation of Porcine Ileum Through Spring-Mediated Mechanical Distraction

INTRODUCTION

Short bowel syndrome is a devastating gastrointestinal disorder in which decreased bowel length results in inadequate absorption causing nutritional deficiencies. Current treatment options are accompanied by significant morbidity. We have proposed spring-mediated distraction enterogenesis as a method to lengthen bowel with success seen in porcine jejunum. We hypothesize that spring-mediated distraction enterogenesis can be demonstrated in porcine ileum with preservation of ileal structure and function.

MATERIALS AND METHODS

Laparotomy was performed on juvenile female mini-Yucatan pigs and a gelatin-encapsulated compressed nitinol spring was inserted into the ileal lumen and affixed proximally and distally. A control segment distal to the spring segment was marked with sutures. Postoperatively, pigs were placed on a liquid diet and euthanized on postoperative day 7. Spring and control segments were measured and processed for immunohistochemistry to evaluate for the presence of vitamin B12-intrinsic factor cotransporter, chromogranin A-producing cells, and 5-HT producing cells.

RESULTS

All seven pigs survived to postoperative day 7 with no adverse effects. On average, pigs gained 84.3 ± 66.4 g/d. Spring segments lengthened 1.5 ± 0.7 cm with a relative lengthening by 128% ± 56%, which was statistically significant when compared to control (P < 0.01). The average density of chromogranin-A cells in control compared to spring segments was not significantly changed (2.9 ± 1.1 cells/mm versus 3.2 ± 1.2 cells/mm, P = 0.17). Both vitamin B12-intrinsic factor cotransporter and 5-HT producing cells were present in both control and lengthened ileum.

CONCLUSIONS

Intraluminal nitinol springs significantly lengthened porcine ileum. The increase in density of enteroendocrine cells may indicate enhanced endocrine function of the lengthened ileum.

Understanding short bowel syndrome: Current status and future perspectives

Short bowel syndrome (SBS) is a rare malabsorptive disorder as a result of the loss of bowel mass mostly secondary to surgical resection of the small intestine. Other causes are vascular diseases, neoplasms or inflammatory bowel disease. The spectrum of the disease is widely variable from single micronutrient malabsorption to complete intestinal failure, depending on the remaining length of the small intestine, the anatomical portion of intestine and the function of the remnant bowel. Over the last years, the management of affected patients has remarkably improved with the increase in patients' quality of life and survival, mainly thanks to advances in home-based parenteral nutrition (PN). In the last ten years new treatment strategies have become available together with increasing experience and the encouraging results with new drugs, such as teduglutide, have added a new dimension to the management of SBS. This review aims to summarize the knowledge available in the current literature on SBS epidemiology, pathophysiology, and its surgical (including intestinal lengthening procedures and intestinal transplantation) and medical management with emphasis on the recent advances. Moreover, this review attempts to provide the new understanding and recent approaches to SBS complications such as sepsis, catheter thrombosis, and intestinal failure-associated liver disease.

Short bowel syndrome in children and adults: from rehabilitation to transplantation

Short bowel syndrome (SBS) is a dramatic clinical condition in both children and adults; the residual bowel length is not sufficient to avoid intestinal failure, with subsequent malnutrition and growth retardation, and intravenous support is required to provide the nutrients normally coming from the intestine. Apart from the primary disease, the medical status can be worsened by complications of intestinal failure: if there are irreversible, the prognosis is poor unless a successful intestinal rehabilitation is achieved. Areas covered: The rescue of the remnant small bowel requires a multidisciplinary expertise to achieve digestive autonomy. The use of intestinal trophic factors has shown encouraging results in improving the intestinal adaptation process. Whenever the residual bowel length is inadequate, in a well-selected population weaning parenteral nutrition (PN) off could be attempted by surgery through lengthening procedures. A further subset of patients, with total and irreversible intestinal failure and severe complications on PN, may have an indication to intestinal transplantation. This procedure is still affected by poor long-term results. Expert commentary: Novel approaches developed through a multidisciplinary team work, such as manipulation of microbiota or tissue bioengineering, should be added to current therapies to treat successfully SBS.

Surgeon's perspective on short bowel syndrome: Where are we?

Short bowel syndrome (SBS) is due to a massive loss of small bowel: the reduction of gut function is below the minimum necessary to maintain health (in adults) and growth (in children) so intravenous supplementation is required. Parenteral nutrition represents the milestone of treatment and surgical attempts should be limited only when the residual bowel is sufficient to increase absorption, reducing diarrhea and slowing the transit time of nutrients, water and electrolytes. The surgical techniques lengthen the bowel (tapering it) or reverse a segment of it: developed in children, nowadays are popular also among adults. The issue is mainly represented by the residual length of the small bowel where ileum has shown increased adaptive function than jejunum, but colon should be considered because of its importance in the digestive process. These concepts have been translated also in intestinal transplantation, where a colonic graft is nowadays widely used and the terminal ileum is the selected segment for a living-related donation. The whole replacement by a bowel or multivisceral transplant is still affected by poor long term outcome and must be reserved to a select population of SBS patients, affected by intestinal failure associated with irreversible complications of parenteral nutrition.