Small bowel transplantation: technical advances/updates

Perioperative alterations in the intestinal microbiota and functional changes mediate innate immune activation after small bowel transplantation

AIM

Small bowel transplantation (SBT) is the only therapy for end-stage short bowel syndrome. However, complicated pathological changes and an increased risk of postoperative infections in the perioperative period are major obstacles to patient survival, but the associated mechanisms remain unclear.

METHODS

To explore perioperative alterations in the intestinal microbiota and their functional changes after SBT, 16S rRNA sequencing of ileostomy effluents and plasma analysis were performed pre-SBT and periodically post-SBT.

RESULTS

The results suggested that the presence of Proteobacteria accelerated bacterial motility and chemotaxis during the first week in post-SBT recipients. Altered gut microbiota impaired intestinal barrier integrity and upregulated 16S rDNA, pathogen-associated molecular pattern (PAMP) and pattern-recognition molecule (PRM) levels in peripheral circulation. Importantly, the levels of neutrophils, monocytes, cytotoxic T lymphocytes, and natural killer cells and the expression of proinflammatory cytokines were increased in the peripheral blood and had potential roles in activating innate immune-mediated inflammatory injury after SBT.

CONCLUSION

Together, our results suggest that altered microbiota and functional changes are probably related to innate immune-mediated inflammatory injury and graft survival after SBT, suggesting that the monitoring and regulation of intestinal microbiota are necessary for SBT patients.

Megacystis Microcolon Intestinal Hypoperistalsis Syndrome: Case Reports and Discussion of the Literature

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare intestinal dysmotility condition that also involves a dilated urinary bladder. It was believed to be an autosomal recessive condition, but genetic studies have suggested possibly an autosomal dominant inheritance pattern. Prenatal diagnosis can be challenging, but MRI and amniotic fluid/digestive fluid studies may be complementary investigations to improve diagnostic accuracy. Prognosis of MMIHS is generally poor and treatment is mostly supportive. To date, bowel transplantation remains the only viable treatment to restore bowel motility. Here we present two additional cases to contribute towards the scant literature on this condition.

Liver, pancreas and small bowel transplantation: current ethical issues

We describe the medical state of the art in liver, pancreas and small bowel transplantation, and portray the ethical issues. Although most ethical questions related to these transplantations are not specific for liver, pancreas and small bowel, they do challenge ethical analysis as well as new policies and clinical procedures. Firstly, outcomes continue to be of utmost concern, as information is only limited available, is developing over time and is surrounded by many uncertainties. Secondly, characteristics of donors and recipients should be carefully evaluated. The question of what qualifies a donor and a recipient should be considered against the background of a quest for extended criteria, embracing marginal cases, and a judgment with regard to what counts as a good enough outcome. Thirdly, ethical principles of autonomy and fairness are pushed, given the circumstance of severe scarcity, towards limits that can easily be crossed.

The application of polymerized porcine hemoglobin (pPolyHb) in the rat small bowel preservation

Small bowel transplantation (SBTx) has become a standard clinical treatment for short bowel syndrome or irreversible intestinal function failure. Optimum preservation of the organ is essential for the success of transplantation. In this study, pPolyHb was used as an additive to hypertonic citrate adenine solution (HCA) to provide oxygen for rat small bowel transplant. Rat small bowels were preserved in HCA, HCA with pPolyHb, and University of Wisconsin solution (UW) for 12, 24, and 36 h, respectively. The results suggested that the preservation effect of HCA with pPolyHb was comparable with the UW solution, and more effective than the HCA solution.

Application of three-dimensional imaging to the intestinal crypt organoids and biopsied intestinal tissues

Two-dimensional (2D) histopathology is the standard analytical method for intestinal biopsied tissues; however, the role of 3-dimensional (3D) imaging system in the analysis of the intestinal tissues is unclear. The 3D structure of the crypt organoids from the intestinal stem cell culture and intestinal tissues from the donors and recipients after intestinal transplantation was observed using a 3D imaging system and compared with 2D histopathology and immunohistochemistry. The crypt organoids and intestinal tissues showed well-defined 3D structures. The 3D images of the intestinal tissues with acute rejection revealed absence of villi and few crypts, which were consistent with the histopathological features. In the intestinal transplant for megacystis microcolon intestinal hypoperistalsis syndrome, the donor's intestinal tissues had well-developed nerve networks and interstitial cells of Cajal (ICCs) in the muscle layer, while the recipient's intestinal tissues had distorted nerve network and the ICCs were few and sparsely distributed, relative to those of the donor. The 3D images showed a clear spatial relationship between the microstructures of the small bowel and the features of graft rejection. In conclusion, integration of the 3D imaging and 2D histopathology provided a global view of the intestinal tissues from the transplant patients.

Factors affecting the duration of mechanical ventilation in patients after intestinal transplantation: preliminary results

OBJECTIVE

Intestinal transplantation (ITx) is a definitive therapy for patients with intestinal failure. However, postoperative respiratory care in such patients remains a clinical challenge. In this study, we investigated the factors affecting the duration of mechanical ventilation in patients who underwent ITx.

METHODS

In this observational study, eight patients who underwent ITx between 2007 and 2013 were studied. They were divided into two groups, with Group E including three patients who could be successfully extubated within 72 hours and Group V including the remaining five, who could not be extubated. The differences in demographical and clinical data between the two groups were evaluated.

RESULTS

The surgery success rate, patient survival rate, and graft survival rate were 100%, 88%, and 75%, respectively. Compared with Group E, postoperative bleeding was significantly higher in Group V (700 ± 420.7 mL vs. 50.0 ± 2.0 mL, p = 0.021). In addition, postoperative respiratory complications including pleural effusion and pneumonia (p = 0.017 and p = 0.0714, respectively) were prone to occur in Group V. Other variables including demographic parameters and clinical data showed no significant differences between the two groups. It was not unexpected that the duration of ventilator use and the length of intensive care unit stay were significantly shorter in Group E.

CONCLUSION

Postoperative blood loss and postoperative respiratory complications might be the factors responsible for delayed extubation in ITx patients. Because the study had few examinees, further studies with a larger population are needed to verify these issues.

Isolated intestinal transplantation for megacystis microcolon intestinal hypoperistalsis syndrome: case report

MMIHS is a rare congenital disease. It is characterized by distended urinary bladder, small colon and intestinal hypoperistalsis, or aperistalsis with normal morphology. There is no specific treatment for MMIHS, and most patients have to be maintained by TPN, which frequently causes TPN-related liver failure, loss of venous access, or catheter-related sepsis. The prognosis of patients with MMIHS is poor, and most patients die early. Multivisceral transplantation including stomach, duodenum, intestine, and liver has been used for the treatment of patients with MMIHS because these patients often have liver failure. We report an eight-yr-old patient with MMIHS who was treated with isolated intestinal transplantation. She had completely oral intake during the four yr of follow-up. The experience in this case suggests isolated intestinal transplantation may be indicated in selected cases with MMIHS.

Waitlist characteristics of patients at a single-center intestinal and multivisceral transplant program

Intestinal transplantation (ITX) can be a successful treatment for patients with irreversible intestinal failure and associated severe complications. Because of long waiting periods and organ shortages, the precise identification of eligible patients and their early referral to centers that perform ITX is important. We retrospectively analyzed all patients who were referred to our center between 2000 and 2011 concerning their referral criteria, waitlist characteristics, and outcome. A total of 87 patients (47 male patients, 40 female patients; median age 39.8 ± 13.4 years) were referred to our center. All patients presented with intestinal failure caused by short bowel syndrome or motility disorders. About 80.5% of patients were evaluated for isolated ITX, modified multivisceral (mMVTX), or multivisceral transplantation (MVTX). About 56.3% were listed at EUROTRANSPLANT, 33.3% suffered from severe secondary organ failure requiring MVTX, and 34.5% were transplanted. 14.3% (all MVTX-candidates) died on the waitlist as a result of infectious complications. The high proportion of MVTX candidates underlines the need for early referral to specialized centers. MVTX-candidates have a high waitlist mortality for different reasons. However, the current allocation policy for MVTX does not mirror the severity of disease and may therefore contribute to high waitlist mortality.

Cambridge-Miami score for intestinal transplantation preoperative risk assessment: initial development and validation

INTRODUCTION

Preoperative quantification of survival after transplantation would assist in assessing patients. We have developed a preliminary preoperative scoring system, called the Cambridge-Miami (CaMi) score, for transplantation of the small intestine either alone or as a composite graft.

METHODS

The score combines putative risk factors for early-, medium-, and long-term survival. Factors included were loss of venous access and impairment of organs or systems not corrected by transplantation. Each factor was scored 0-3. A score of 3 indicated comorbidity approaching a contraindication for transplantation, that which might lead to but was not currently an adverse risk factor scored 1, and that presenting a definite but moderate increase in risk scored 2. The preoperative scores of 20 patients who had received intestinal transplants either isolated or as part of a cluster graft, who had either been followed up postoperatively for at least 10 years, or died within 10 years were compared with their survivals.

RESULTS

Postoperative survival and CaMi score inversely correlated when analysed using Spearman test (r(s) = -0.82; P = .0001). A score of <3 associated with survival > or =3 years (12/12 patients) and >3 with survival of <6 months (4/4). Patient Kaplan-Meier (KM) survival curves for patients grouped according to CaMi score became significantly different from group 0 to group 3. Using this as a threshold score patients grouped as either >2 or <3 had significantly different survival rates (log-rank; P = .0001), KM median survival hazard ratio (HR) = 6, and rate of death KM HR = 5. Receiver-operator characteristics indicate a high degree of accuracy for prediction of death with an area under the curve (C statistic) at 3 years of 0.98, at 5 years of 0.82, and at 10 years of 0.65.

CONCLUSION

This initial validation suggested that the preoperative CaMi score predicted postoperative survival.

Intestine transplantation in children: update 2010

This article reviews the current status of pediatric intestinal transplantation, focusing on referral and listing criteria, surgical techniques, patient management, monitoring, complications after transplant, and short- and long-term patient outcome. Intestine transplantation has become the standard of care for children who develop life-threatening complications associated with intestinal failure. The results of intestinal failure treatment have significantly improved in the last decade following the establishment of gut rehabilitation programs and advances in transplant immunosuppressive protocols, surgical techniques, and posttransplant monitoring. The 1-year patient survival is now 80% and more than 80% of the children who survive the transplant are weaned off parenteral nutrition. Early referral for pretransplant assessment and careful follow-up after transplant with prompt recognition and treatment of transplant-related complications are key factors contributing to superior patient outcomes and survival. The best results are being obtained at high-volume centers with survival rates of up to 75% at 5 years.

Esophageal varices in chronic intestinal insufficiency in absence of portal hypertension or liver cirrhosis: case report

We report the case of a 62-year-old man with short-bowel syndrome, referred for intestinal transplantation, who had esophageal varices (EV) due to superior vena cava (SVC) thrombosis. Pretransplantation work-up revealed protein S deficiency. Results of liver function tests were normal. Upper endoscopy showed grade II to III EV in the upper and middle segments of the esophagus. Computed tomography demonstrated thrombosis of the jugular, subclavian, and SVC veins and marked collateral vessels in the chest. Transient elastography yielded normal findings. A liver biopsy specimen showed a normal aspect of the liver, without fibrosis or liver cirrhosis. Presence of EV in a patient with chronic intestinal insufficiency may be related to collateral venous circulation associated with SVC thrombosis in the absence of portal hypertension. In this situation, an isolated intestinal graft is indicated.