Intestinal transplantation: an update

Nutrition Management of Small Bowel Transplant Patients

Nutrition therapy after small bowel or combined liver/small bowel transplantation is challenging. The objective is to restore enteral autonomy to a patient with a complex past surgical history and equally complex posttransplant immunosuppressive regimen in the context of a newly created surgical anatomy. Improved surgical techniques and immunosuppressive regimens have led to superior outcomes. Accompanying these advances is a range of nutrition issues that require specific management strategies. This review outlines the current clinical practice and decision making used to create individualized nutrition regimens for small bowel or combined liver/small bowel transplant recipients. Successful small bowel transplant outcomes require a coordinated effort from a transplant team to restore nutritional autonomy to transplant recipients and free them from parenteral nutrition.

Living Long With Short Bowel Syndrome: A Historical Case of Twenty-Nine Years of Living With Home Parenteral Nutrition

BACKGROUND

This paper traces the 29-year survival of Robert Thomas, who received home parenteral nutrition (PN), and contrasts his oral narrative with the clinical history of PN.

METHODS

Interviews, chart review, review of the literature, and historical analysis.

RESULTS

Bobby Thomas was part of an early group of patients scattered throughout the country who, with their medical team, provided the foundation for more successful survival with home PN. They learned together and taught numerous nutrition support clinicians the intricacies of patient management. The importance of the patient to the teaching function of new and experienced practitioners is highly critical. Patients like Robert Thomas gave practitioners firsthand evidence of both the tenacity of the human spirit and the complexity and difficulties of chronic illness and its treatments.

CONCLUSIONS

While Bobby struggled with the complications and difficulties that came with the disease and the treatment keeping him alive, his own experiences over 29 years, as told to his medical team during his treatment and to informed interviewers before he died, tell a story that is both intersecting and parallel to the medical history. Pioneering patients like Bobby Thomas confirm the possibility of survival. They also, through their own negotiations to maintain a sense of control, can live lives they themselves help define.

The Surgical Approach to Short Bowel Syndrome - Autologous Reconstruction versus Transplantation

BACKGROUND

Short bowel syndrome (SBS) is a state of malabsorption resulting from massive small bowel resection leading to parenteral nutrition (PN) dependency. Considerable advances have been achieved in the medical and surgical management of SBS over the last few decades.

METHODS

This review discusses in detail the surgical approach to SBS.

RESULTS

Widespread use of PN enables long-term survival in patients with intestinal failure but at the cost of PN-associated life-threatening complications including catheter-associated blood stream infection, venous thrombosis, and liver disease. The goal of management of intestinal failure due to SBS is to enable enteral autonomy and wean PN by means of a multi-disciplinary approach. Availability of modified enteral feeding formulas have simplified nutrition supplementation in SBS patients. Similarly, advances in the medical field have made medications like growth hormone and glucagon-like peptide (GLP2) available to improve water and nutrient absorption as well as to enable achieving enteral autonomy. Autologous gastrointestinal reconstruction (AGIR) includes various techniques which manipulate the bowel surgically to facilitate the bowel adaptation process and restoration of enteral nutrition. Ultimately, intestinal transplantation can serve as the last option for the cure of intestinal failure when selectively applied.

CONCLUSION

SBS continues to be a challenging medical problem. Best patient outcomes can be achieved through an individualized plan, using various AGIR techniques to complement each other, and intestinal transplantation as a last resort for cure. Maximum benefit and improved outcomes can be achieved by caring for SBS patients at highly specialized intestinal rehabilitation centers.

Where are we at with short bowel syndrome and small bowel transplant

Intestinal failure can be defined as the critical reduction of functional gut mass below the minimal amount necessary for adequate digestion and absorption to satisfy body nutrient and fluid requirements in adults or children. Short bowel syndrome (SBS) is characterized by a state of malabsorption following extensive resection of the small bowel. SBS may occur after resection of more than 50% and is certain after resection of more than 70% of the small intestine, or if less than 100 cm of small bowel is left. Several treatment modalities other than total parenteral nutrition, including hormones (recombinant human growth hormone, glucagon-like peptide-2) and tailoring surgeries (Bianchi procedure, serial transverse enteroplasty), had been proposed, however these were either experimental or inefficient. Small bowel transplant is a rather new approach for SBS. The once feared field of solid organ transplantation is nowadays becoming more and more popular, even in developing countries. This is partially secondary to the developments in immunosuppressive strategy. In this regard, alemtuzumab deserves special attention. There are more complex surgeries, such as multivisceral transplantation, for multi-organ involvement including small bowel. This latter technique is relatively new when compared to small bowel transplant, and is performed in certain centers worldwide. In this review, an attempt is made to give an insight into small bowel syndrome, small bowel transplantation, and related issues.

Chronic idiopathic intestinal pseudo-obstruction treated by near total small bowel resection: a 20-year experience

BACKGROUND

Patients suffering from chronic idiopathic intestinal pseudo-obstruction (CIIPO) clearly benefit from home parenteral nutrition (HPN) to maintain adequate nutritional status and general health. But intestinal dismotility can seriously disturb their quality of life (QOL) to the point of making it intolerable.

AIM

Report our clinical experience on the management of chronic severe occlusive symptoms in CIIPO by near total small bowel resection.

METHODS

A 20-year retrospective study of eight patients with end-stage CIIPO maintained on HPN and suffering of chronic occlusive symptoms refractory to medical treatment underwent extensive small bowel resection preserving less than 70 cm of total small bowel and less than 20 cm of ileum. The jejunum was anastomosed either to the ileum or to the colon.

RESULTS

Six patients were completely relieved from obstructive symptoms. Two patients needed a second operation to remove the residual ileum because of recurrent symptoms. Two were significantly improved. There was no post-operative death. All patients experienced a significant improvement in their QOL.

CONCLUSION

Near total small bowel resection appears to be a safe and effective procedure in end-stage CIIPO patients, refractory to optimal medical treatment.

Mouse embryonic stem cells give rise to gut-like morphogenesis, including intestinal stem cells, in the embryoid body model

Embryonic stem (ES) cells have been proposed as candidates for cell replacement therapy in patients with intestinal failure because these cells can be expanded indefinitely without losing their pluripotent phenotype. We investigated the differentiation capacity of mouse ES cells into gut-like structures, including intestinal stem cells, and defined culture conditions for efficient induction of formation of these structures. ES cell-derived gut-like structures (ES-guts) were reproducibly induced in developing embryoid bodies (EBs) by day 21 of differentiation culture. ES-guts contained an endodermal epithelium, a smooth muscle layer, interstitial cells of Cajal, and enteric neurons and showed spontaneous contraction. Transplantation of ES-guts under the kidney capsules of immunodeficient mice induced formation of highly differentiated epithelium composed of absorptive cells and goblet cells in the grafts. Immunoreactivity for Musashi-1 (Msi-1), a marker of intestinal stem cells, was detected in 1.9% of the columnar epithelial cells in the graft. Culture with 0.1% dimethyl sulfoxide increased the numbers of ES-guts in EBs, and serum-replacement (SR) culture, in comparison to standard ES culture containing 15% serum, increased the area ratio of ES-guts to EBs. SR culture also promoted maturation of epithelium to form a single layer of columnar epithelial cells, including absorptive cells and goblet cells. Expression of Msi-1 mRNA and protein was significantly enhanced when EBs were cultured under SR conditions. In conclusion, SR conditions efficiently induce formation of ES-guts and promote differentiation of epithelium, including intestinal stem cells. These results suggest the feasibility of cell-based therapy for intestinal failure based on ES cell culture systems.

Outcomes in children after intestinal transplant

OBJECTIVE

The survival rates after pediatric intestinal transplant according to underlying disease are unknown. The objective of our study was to describe the population of pediatric patients receiving an intestinal transplant and to evaluate survival according to specific disease condition.

PATIENTS

Pediatric patients (< or =21 years of age) with intestinal failure meeting criteria for intestinal transplant were included in the study.

METHODS

A retrospective review of the United Network for Organ Sharing intestinal transplant database (January 1, 1991, to May 16, 2008), including all pediatric transplant centers participating in the United Network for Organ Sharing, was conducted. The main outcome measures were survival and mortality.

RESULTS

Eight hundred fifty-two children received an intestinal transplant (54% male). Median age and weight at the time of transplant were 1 year (interquartile rage: 1-5) and 10.7 kg (interquartile rage: 7.8-21.7). Sixty-nine percent of patients also received a simultaneous liver transplant. The most common diagnoses among patients who received a transplant were gastroschisis (24%), necrotizing enterocolitis (15%), volvulus (14%), other causes of short-gut syndrome (19%), functional bowel syndrome (16%), and Hirschsprung disease (7%). The Kaplan-Meier curves demonstrated variation in patient survival according to diagnosis. Cox regression analysis confirmed a survival difference according to diagnosis (P < .001) and demonstrated a survival advantage for those patients listed with a diagnosis of volvulus (P < .01) compared with the reference gastroschisis. After adjusting for gender, recipient weight, and concomitant liver transplant, children with volvulus had a lower hazard ratio for survival and a lower risk of mortality.

CONCLUSIONS

Survival after intestinal transplant was associated with the underlying disease state. The explanation for these findings requires additional investigation into the differences in characteristics of the population of children with intestinal failure.

Outcomes in children with intestinal failure following listing for intestinal transplant

PURPOSE

The purpose of this study was to describe the population of pediatric patients waiting for intestinal transplant and to evaluate the risk of death or transplant by specific disease states.

METHODS

We studied the United Network for Organ Sharing (UNOS) database (Jan 1,1991 to 5/16/08) for patients 21 years old or younger at first listing for intestinal transplant and examined their age, sex, weight, and diagnoses. Time to list removal was summarized with cumulative incidence curves. Multinomial logistic regression was used to compare relative risk ratios for removal from the list for transplant, death, or other reasons.

RESULTS

We identified 1712 children listed for intestinal transplant (57% male, 51% <1 year, weight 8.1 kg [IQR, 6.1-14.1] at listing). Median age and weight at transplant (n = 852) were 1 year (IQR, 1-5) and 10 kg (IQR, 6.5-16.3). Regression analysis demonstrated significant differences in outcomes among disease conditions (P < .001). Compared to the gastroschisis group, the relative risk ratio for death versus transplant was higher in the necrotizing enterocolitis group (P = .015), lower in the short gut syndrome group (P = .001), and not different in the volvulus group (P = .94) after adjustment for weight and sex.

CONCLUSIONS

We conclude that the relative risk of transplant vs death varies significantly by the disease condition of the patient.

The reactions of specific neuron types to intestinal ischemia in the guinea pig enteric nervous system

Damage following ischemia and reperfusion (I/R) is common in the intestine and can be caused during abdominal surgery, in several disease states and following intestinal transplantation. Most studies have concentrated on damage to the mucosa, although published evidence also points to effects on neurons. Moreover, alterations of neuronally controlled functions of the intestine persist after I/R. The present study was designed to investigate the time course of damage to neurons and the selectivity of the effect of I/R damage for specific types of enteric neurons. A branch of the superior mesenteric artery supplying the distal ileum of anesthetised guinea pigs was occluded for 1 h and the animals were allowed to recover for 2 h to 4 weeks before tissue was taken for the immunohistochemical localization of markers of specific neuron types in tissues from sham and I/R animals. The dendrites of neurons with nitric oxide synthase (NOS) immunoreactivity, which are inhibitory motor neurons and interneurons, were distorted and swollen by 24 h after I/R and remained enlarged up to 28 days. The total neuron profile areas (cell body plus dendrites) increased by 25%, but the sizes of cell bodies did not change significantly. Neurons of type II morphology (intrinsic primary afferent neurons), revealed by NeuN immunoreactivity, were transiently reduced in cell size, at 24 h and 7 days. These neurons also showed signs of minor cell surface blebbing. Calretinin neurons, many of which are excitatory motor neurons, were unaffected. Thus, this study revealed a selective damage to NOS neurons that was observed at 24 h and persisted up to 4 weeks, without a significant change in the relative numbers of NOS neurons.

Present status and future perspectives of intestinal transplantation

Intestinal transplantation (ITx) is the only definitive therapy for irreversible intestinal failure. Owing to the limited short- and long-term graft survival over the years, ITx has been a complementary treatment to home parenteral nutrition. However, the development of intestinal and multivisceral transplantation has been significant over the past 15-20 years owing to the progress in immunosuppressive therapy, refinement of surgical techniques, post-transplant care, intestinal immunology, and immunological as well as anti-infectious monitoring. The improvement of patient- and graft survival over the last few years together with data on the cost effectiveness of ITx, following 2 years after transplantation, may require a redefinition of the indication for ITx.

Sequential observations show upregulation of TGF-beta1 at the early phase of chronic small bowel rejection in rats

Although TGF-beta1 is related to chronic rejection in various solid organs, its role remains controversial in the setting of small bowel transplantation. The aim of this study is to investigate the distinct role of TGF-beta1 and its receptors in the setting of chronic small bowel rejection. Sequential protocol biopsies were performed every 2 weeks from week 2 till week 8 after transplantation and recipients were sacrificed at week 16 as the end point. Gene expression was evaluated by SYBR Green I real-time polymerase chain reaction and protein was determined by immunohistochemistry. The gene expressions of TGF-beta1 and Type I receptor were upregulated and attained statistical significance at 4, 6 and 8 weeks in allografts. Dynamic expressions of TGF-beta1 and Type I receptor mRNA shown by sequential protocol biopsies support the view that TGF-beta1 signaling is involved in the pathogenesis of chronic small bowel rejection, especially at the early phase.

Short-Term Anti-CD4 Plus Anti-TNF-α Receptor Treatment in Allogeneic Small Bowel Transplantation Results in Long-Term Survival

BACKGROUND

Despite improved immunosuppression, intestinal transplantation is still complicated by severe rejection episodes. To further improve immunosuppressive concepts, we evaluated an anti-CD4 antibody and an anti-tumor necrosis factor (TNF)-alpha monoclonal antibody for their immunosuppressive efficacy in the standard rat model of intestinal transplantation.

METHODS

Intestinal transplantation was performed in the DA to Lewis combination, and recipients were treated perioperatively with either the anti-CD4 antibody RIB5/2 (day -1, 0, postoperative days 1, 2, 4, 7, 10, 14, 17, and 21), the anti-TNF antibody etanercept (60 min before reperfusion, postoperative days 3, 6, and 9) or a combination of both. Survival, histology and expression of immunologic mediator genes on days 3 and 4 after transplantation were investigated.

RESULTS

Treatment with anti-CD4 antibody alone (19.71+/-5.94) and the antibody combination (171.58+/-122.76) prolonged survival. The chemokine MIP-1alpha was significantly decreased in both anti-CD4 antibody treatment groups, possibly indicating an additional effect of the TNF-alpha blockade on the immune modulation by RIB5/2.

CONCLUSIONS

Our study demonstrated long-term graft survival in short-term treatment with a combination of an anti-CD4 antibody and a TNF-alpha antibody in more than 50% of the recipients of intestinal grafts. Such a combined approach could also be useful in clinical small bowel transplantation.

Role and significance of plasma citrulline in the early phase after small bowel transplantation in pigs

A reliable serological marker of acute cellular rejection (ACR) after small bowel transplantation (SBTx) is still missing. Plasma citrulline level (PCL) reflects the functional integrity of intestinal mucosa which is partially lost during ACR. The aim of our study was to investigate the role of PCL as marker of ACR after SBTx. Eighteen German landrace pigs were used and divided into three groups. Group 1 (G1), autologous SBTx (n = 4) as control; group 2 (G2), allogeneic SBTx without immunosuppression (IS) (n = 7) and group 3 (G3), allogeneic SBTx with IS (n = 7). IS consisted of tacrolimus and steroids without induction treatment. Observation period was 14 days. Mucosal biopsies were obtained intraoperatively and daily using a Thiry-Vella loop. ACR was differentiated into indeterminate, mild, moderate and severe using a standardized grading schema. PCL was measured daily. An ACR onset occurred generally from postoperative day 4 both in G2 and G3 as mild form and developed differently in the two groups: moderate to severe in G2 and indeterminate to mild in G3. A significant decline of PCL occurred only in cases of moderate and severe ACR, but not in cases of indeterminate and mild ACR. The PCL failed as a marker in the early diagnosis of ACR and became reliable only when advanced mucosal damage was present.

Determinants of quality of life in home parenteral nutrition

PURPOSE OF REVIEW

To highlight the most important and salient articles regarding home parenteral nutrition and quality of life published within the last 3 years.

RECENT FINDINGS

In recent years, quality of life research in home parenteral nutrition has highlighted the need for a therapy-specific validated questionnaire. Several papers suggest a greater psychological input is required to better understand and evaluate this patient population. Issues surrounding the use of home parenteral nutrition in malignancy have arisen, prompting discussion on ideal timing and candidacy for home parenteral nutrition. Intestinal transplantation is evolving and improving, making it a possible alternative to home parenteral nutrition. Earlier referral is suggested as late referral can result in poorer outcome.

SUMMARY

Home parenteral nutrition is a life-sustaining therapy for individuals with intestinal failure. There is now a relatively large amount of research into the quality of life in this population, but more focused measurements (in the form of validated therapy-specific questionnaires) are required to answer questions relating to cancer and intestinal transplantation.

La greffe intestinale

Even though surgical techniques for isolated intestine, liver-intestine, and multivisceral transplantations were developed in the 1960's, very few patients were transplanted before 1990 because initial immunosuppression regimens were insufficient, making intestine transplantation impossible. Intestine transplantation resulted in death in most patients within days or months. The discouraging results of the first clinical trials were due to technical complications, sepsis, and the failure of conventional immunosuppression to control rejection. By 1990 the development of tacrolimus-based immunosuppression and improved surgical techniques, the increased array of potent immunosuppressive medications, infection prophylaxis, and suitable patient selection helped improve actuarial graft and patient survival rates for all types of intestine transplantation. The aims of this review are to describe the current status of intestine transplantation including the underlying diseases and conditions that may be indications for intestine transplantation, to identify patient populations for this indication, to provide key steps for patient evaluation, to summarize current recommendations for immunosuppression, to list the most common postoperative complications, and to discuss the international experience of small bowel transplantation compiled and analyzed by the International Intestine Transplant Registry since 1985.

Short bowel syndrome: parenteral nutrition versus intestinal transplantation. Where are we today?

Current management of short bowel syndrome (SBS) revolves around the use of home TPN (HPN). Complications include liver disease, catheter-related infections or occlusions, venous thrombosis, and bone disease. Patient survival with SBS on TPN is 86% and 75% at 2 and 5 years, respectively. Surgical management of SBS includes nontransplant surgeries such as serial transverse enteroplasty and reanastomosis. Small bowel transplant has become increasingly popular for management of SBS and is usually indicated when TPN cannot be continued. Posttransplant complications include graft-versus-host reaction, infections in an immunocompromised patient, vascular and biliary diseases, and recurrence of the original disease. Following intestinal-only transplants, patient and graft survival rate is 77% and 66% after 1 year. After 5 years the survival figures are 49% and 34%, respectively. Future improvements in survival and quality of life will enhance small bowel transplant as a viable treatment option for patients with SBS.

Current status of transplantation of the small intestine

The evolution of small bowel transplantation has been significant over the past 20 years to the point at which it can now be considered a viable and often successful option in the treatment of many forms of short bowel syndrome. A refinement of surgical techniques, improved immunosuppression, enhanced understanding of gut immunology, and better treatment and prevention of complications have contributed to a marked improvement in graft and patient survival. Whereas this transplant population is still beset with many potential complications after isolated bowel or multivisceral transplantation and long-term graft survival (like with other solid organ transplants) remains a challenge, the future holds promise for a continuation of the current positive trend of improvement in several areas.

Metabolic bone disease in gastrointestinal illness

Metabolic bone disease is often silent, often undiagnosed, and occurs frequently in patients with chronic gastrointestinal illnesses. Potentially modifiable risk factors, such as malnutrition, malabsorption, prolonged use of glucocorticoids, and a sedentary lifestyle, can lead to low bone mass, an increased rate of bone loss, and debilitating bone disease. This article explores common gastrointestinal illnesses that place patients at risk for developing metabolic bone disease. Concepts are presented to assist the practitioner in identifying patients at risk; clinical evaluation and diagnostic test selection are discussed, and therapeutic options for the prevention and treatment of metabolic bone disease in gastrointestinal illness are presented.

Sustainability of mechanically lengthened bowel in rats

INTRODUCTION

It has been shown that the length of an intestinal segment may be doubled by applying gradual mechanical stretching. This study evaluated whether the lengthened intestinal segment retained the structure and function after the stretching device was removed.

METHODS

A 1.5-cm jejunal segment was separated from intestinal continuity in 20 rats. After advancing a screw into the isolated jejunal segment by 5 mm 3 times a week until it was stretched by 3 cm, the screw was removed. Three weeks later, the jejunal segments were retrieved for analyses. Comparisons were made between the lengthened jejunal segments.

RESULTS

The jejunal segment doubled its length after gradual stretching and retained this length 3 weeks after the screw removal (3.1 +/- 0.8 vs 3.2 +/- 0.4 cm, P > .05). The villous height, the muscular thickness, and the total alkaline phosphatase and lactase activities of the stretched jejunal segments were also unchanged 3 weeks after the screw removal.

CONCLUSIONS

Mechanical force induced the sustained lengthening of isolated jejunal segments in rats. The histologic and enzymatic alterations also persisted 3 weeks after the mechanical force was removed. This phenomenon may provide a novel method for the treatment of short bowel syndrome.