Current status of intestinal transplantation

Improved Preservation of Rat Small Intestine Transplantation Graft by Introduction of Mesenchymal Stem Cell-Secreted Fractions

Segmental grafts from living donors have advantages over grafts from deceased donors when used for small intestine transplantation. However, storage time for small intestine grafts can be extremely short and optimal graft preservation conditions for short-term storage remain undetermined. Secreted factors from mesenchymal stem cells (MSCs) that allow direct activation of preserved small intestine grafts. Freshly excised Luc-Tg LEW rat tissues were incubated in preservation solutions containing MSC-conditioned medium (MSC-CM). Preserved Luc-Tg rat-derived grafts were then transplanted to wild-type recipients, after which survival, injury score, and tight junction protein expression were examined. Luminance for each graft was determined using in vivo imaging. The findings indicated that 30-100 and 3-10 kDa fractions of MSC-CM have superior activating effects for small intestine preservation. Expression of the tight-junction proteins claudin-3, and zonula occludens-1 preserved for 24 h in University of Wisconsin (UW) solution containing MSC-CM with 50-100 kDa, as shown by immunostaining, also indicated effectiveness. Reflecting the improved graft preservation, MSC-CM preloading of grafts increased survival rate from 0% to 87%. This is the first report of successful transplantation of small intestine grafts preserved for more than 24 h using a rodent model to evaluate graft preservation conditions that mimic clinical conditions.

A study of the mechanisms responsible for the action of new immunosuppressants and their effects on rat small intestinal transplantation

In a series of studies, using an identical rat intestinal transplantation model, we evaluated the effects of several drugs. FK-506 caused a significant attenuation in the proliferation of allogeneic CD4+ T cells and IFN-γ secreting effector functions. FYT720 resulted in a marked reduction in the numbers of lymphocytes, associated with a reduction of T cell recruitment, in grafts. An anti-MAdCAM antibody was next reported to significantly down-regulate CD4+ T cell infiltration in intestinal grafts by blocking the adhesion molecule, and could be useful as an induction therapy. Concerning TAK-779, this CCR5 and CXCR3 antagonist diminished the number of graft-infiltrating cells by suppressing the expression of their receptors in the graft. As a result, it reduced the total number of recipient T cells involved in graft rejection. As the next step, we focused on the participation of monocytes/ macrophages in this field. PQA-18 has been the focus of a novel immunosuppressant that attenuates not only the production of various cytokines, such as IL-2 & TNF-α, on T cells, but the differentiation of macrophages by inhibiting PAK2 as well. In this report, we summarize our previous studies not only regarding the above drugs, but on an anti-complement drug and a JAK inhibitor as well.

State-of-the-art colorectal disease: conservative surgical management of intestinal failure in adults

PURPOSE

Intestinal failure (IF) is defined by the reduction of gut function under the minimum necessary for adequate absorption of macronutrients and/or electrolytes, requiring home parenteral nutrition (HPN) to maintain health and/or growth. Among the different causes of IF, short bowel syndrome (SBS) is one of the main causes of IF in adults. Management of IF and SBS is complex and requires a multidisciplinary approach. The aim of this study was to review the place and the modalities of conservative surgical procedures performed for IF in adults.

RESULTS-CONCLUSION

HPN has drastically modified the poor prognosis of these patients, leading to an overall survival around 70-75% at 5 years in patients without cancer. However, HPN is associated with life-threatening long-term complications, including liver failure and catheter-related complications, main causes of deaths for these patients. Surgery can be proposed, in order to try to reduce SBS consequences with either conservative or non-conservative procedures. Simple bowel continuity restoration should be performed as often as possible in order to wean or at least to reduce HPN. Lengthening procedures are proposed to increase the absorption surface of the remnant bowel. These procedures can be only performed on a dilated small bowel. The slowing transit time procedure is represented by segmental reversal of the small bowel. Intestinal transplantation is the last surgical option for patients with IF but is still today associated with high mortality and failure rates. Thus, conservative procedures have a major role in the surgical armentarium for patients with IF.

Dlx1/2 mice have abnormal enteric nervous system function

Decades ago, investigators reported that mice lacking DLX1 and DLX2, transcription factors expressed in the enteric nervous system (ENS), die with possible bowel motility problems. These problems were never fully elucidated. We found that mice lacking DLX1 and DLX2 (Dlx1/2-/- mice) had slower small bowel transit and reduced or absent neurally mediated contraction complexes. In contrast, small bowel motility seemed normal in adult mice lacking DLX1 (Dlx1-/-). Even with detailed anatomic studies, we found no defects in ENS precursor migration, or neuronal and glial density in Dlx1/2-/- or Dlx1-/- mice. However, RNA sequencing of Dlx1/2-/- ENS revealed dysregulation of many genes, including vasoactive intestinal peptide (Vip). Using immunohistochemistry and reporter mice, we then found that Dlx1/2-/- mice have reduced VIP expression and fewer VIP-lineage neurons in their ENS. Our study reveals what we believe is a novel connection between Dlx genes and Vip and highlights the observation that dangerous bowel motility problems can occur in the absence of easily identifiable ENS structural defects. These findings may be relevant for disorders like chronic intestinal pseudo-obstruction (CIPO) syndrome.

Intra-abdominal infections among adult intestinal and multivisceral transplant recipients in the 2-year post-operative period

BACKGROUND

Intestinal and multivisceral transplantations are treatment options for patients with intestinal failure. Transplantation is often complicated by abdominal and/or bloodstream infections in the post-operative period.

METHODS

A retrospective chart review of all adults who underwent intestinal or multivisceral transplantation at our institution from 2003 to 2015 was performed. Data were collected for 2 years post transplant.

RESULTS

A total of 106 intestinal or multivisceral transplants were performed in 103 patients. The median age at the time of transplant was 44 (IQR: 34-52) with 55% (n = 58) male and 45% (n = 48) female. There were 46 (43%) intra-abdominal infections post transplant among the 103 patients, and six transplant recipients (13%) developed concurrent bloodstream infections. The median time to first intra-abdominal infection was 23 days (IQR: 10-48). For those with organisms isolated in culture, forty-seven percent of the isolates were gram negative, 39% gram positive, 7% anaerobes, and 7% yeast. The most common isolates were enterococci at 28%, E. coli at 14%, and Klebsiella spp at 13%. Sixty-three percent of the enterococci were vancomycin-resistant enterococci (VRE), and 22% of the gram-negative isolates were extended spectrum beta-lactamases (ESBLs). Patients with intra-abdominal infections had longer hospital post-transplant length of stays at a median of 35 days (IQR: 25-48) vs 23 days (IQR: 17-33) for those without infections, P = .0012. There was no difference in all-cause mortality in patients with or without intra-abdominal infections, P = .654.

CONCLUSIONS

Intra-abdominal infections are common in intestinal or multivisceral transplant recipients, but despite this complication, we found no increased risk of mortality. These transplant recipients are also at risk for infection with drug-resistant organisms.

Donor-Specific Antibodies in Pediatric Intestinal and Multivisceral Transplantation: The Role of Liver and Human Leukocyte Antigen Mismatching

Rejection is one of the most important drawbacks for graft and patient survival in intestinal and multivisceral transplantation. However, there is no consensus on the diagnostic criteria for humoral rejection, and the literature about the role of donor-specific antibodies (DSA) on allograft outcome and the risk factors that contribute to their development is scant with contradictory results. The present study analyzes the role of DSA exclusively in a pediatric cohort of 43 transplants. Among our patients, 11.6% showed preformed DSA, but they did not correlate with more rejection or less allograft survival. Having previous transplants was the main sensitization factor with an odds ratio (OR) = 44.85 (P = 0.001). In total, 16.3% of recipients developed de novo donor-specific antibodies (dnDSA), mostly directed against human leukocyte antigen (HLA) class II, polyspecific and complement fixing. Additionally, the presence of dnDSA had a deleterious effect on graft rejection (hazard ratio [HR] = 11.00; P = 0.01) and survival (HR = 66.52; P < 0.001) in an observational period of 5 years after transplantation. The inclusion of the liver emerged as the main protective factor against dnDSA development with an OR = 0.07 (P = 0.007). The analysis of HLA compatibility at the serological and epitope level with the computational tools HLAMatchmaker and PIRCHE revealed no association between HLA mismatching and dnDSA. In conclusion, this study performed in pediatric recipients shows the deleterious effect of dnDSA on intestinal transplantation supported by the complement-fixing activity observed. Additionally, the liver inclusion in the allografts showed to be a protective factor against dnDSA generation.

Living Donor Intestinal Transplantation

Living donor intestinal transplantation (LDIT) has been improved leading to results comparable to those obtained with deceased donors. LDIT should be limited to specific indications and patient selection. The best indication is combined living donor intestinal/liver transplantation in pediatric recipients with intestinal and hepatic failure; the virtual elimination of waiting time may avoid the high mortality experienced by candidates on the deceased waiting list. Potentially, LDIT could be used in highly sensitized recipients to allow the application of de-sensitization protocols. In the case of available identical twins or HLA-identical sibling, LDIT has a significant immunologic advantage and should be offered.

Intestinal transplantation: a review

PURPOSE OF REVIEW

The purpose of this article is to review the existing literature on the current indications, surgical techniques, immunosuppressive therapy and outcomes following intestinal transplantation (ITx).

RECENT FINDINGS

Over recent years, ITx has become a more common operation with approximately 2500 procedures carried out worldwide by 2014. It is reserved for patients with intestinal failure and who have developed complications of home parenteral nutrition or who have a high risk of dying from their underlying disease. Recent advances such as the improvement in survival rates, not only for isolated small bowel transplants but also following inclusion of a liver graft in combined liver-small bowel transplant, and the utility of citrulline as a noninvasive biomarker to appreciate acute rejection herald an exciting shift in the field of ITx.

SUMMARY

With advancements in immunosuppressive drugs, induction regimens, standardization of surgical techniques and improved postoperative care, survival is increasing. In due course, it will most likely become as good as remaining on home parenteral nutrition and as such could become a viable first-line option.

Current status of intestinal and multivisceral transplantation

Clinical-nutritional autonomy is the ultimate goal of patients with intestinal failure (IF). Traditionally, patients with IF have been relegated to lifelong parenteral nutrition (PN) once surgical and medical rehabilitation attempts at intestinal adaptation have failed. Over the past two decades, however, outcome improvements in intestinal transplantation have added another dimension to the therapeutic armamentarium in the field of gut rehabilitation. This has become possible through relentless efforts in the standardization of surgical techniques, advancements in immunosuppressive therapies and induction protocols and improvement in postoperative patient care. Four types of intestinal transplants include isolated small bowel transplant, liver-small bowel transplant, multivisceral transplant and modified multivisceral transplant. Current guidelines restrict intestinal transplantation to patients who have had significant complications from PN including liver failure and repeated infections. From an experimental stage to the currently established therapeutic modality for patients with advanced IF, outcome improvements have also been possible due to the introduction of tacrolimus in the early 1990s. Studies have shown that intestinal transplant is cost-effective within 1-3 years of graft survival compared with PN. Improved survival and quality of life as well as resumption of an oral diet should enable intestinal transplantation to be an important option for patients with IF in addition to continued rehabilitation. Future research should focus on detecting biomarkers of early rejection, enhanced immunosuppression protocols, improved postoperative care and early referral to transplant centers.

Evidence of Absorptive Function in vivo in a Neo-Formed Bio-Artificial Intestinal Segment Using a Rodent Model

A promising therapeutic approach for intestinal failure consists in elongating the intestine with a bio-engineered segment of neo-formed autologous intestine. Using an acellular biologic scaffold (ABS), we, and others, have previously developed an autologous bio-artificial intestinal segment (BIS) that is morphologically similar to normal bowel in rodents. This neo-formed BIS is constructed with the intervention of naïve stem cells that repopulate the scaffold in vivo, and over a period of time, are transformed in different cell populations typical of normal intestinal mucosa. However, no studies are available to demonstrate that such BIS possesses functional absorptive characteristics necessary to render this strategy a possible therapeutic application. The aim of this study was to demonstrate that the BIS generated has functional absorptive capacity. Twenty male August × Copenhagen-Irish (ACI) rats were used for the study. Two-centimeter sections of ABS were transplanted in the anti-mesenteric border of the small bowel. Animals were studied at 4, 8, and 12 weeks post-engraftment. Segments of intestine with preserved vascular supply and containing the BIS were isolated and compared to intestinal segments of same length in sham control animals (n = 10). D-Xylose solution was introduced in the lumen of the intestinal segments and after 2 h, urine and blood were collected to evaluate D-Xylose levels. Quantitative analysis was performed using ELISA. Morphologic, ultrastructural, and indirect functional absorption analyses were also performed. We observed neo-formed intestinal tissue with near-normal mucosa post-implantation as expected from our previously developed model. Functional characteristics such as morphologically normal enterocytes (and other cell types) with presence of brush borders and preserved microvilli by electron microscopy, preserved water, and ion transporters/channels (by aquaporin and cystic fibrosis transmembrane conductance regulator (CFTR)) were also observed. The capacity of BIS containing neo-formed mucosa to increase absorption of d-Xylose in the blood compared to normal intestine was also confirmed. With this study, we demonstrated for the first time that BIS obtained from ABS has functional characteristics of absorption confirming its potential for therapeutic interventions.

Innate Lymphoid Cells Groups 1 and 3 in the Epithelial Compartment of Functional Human Intestinal Allografts

We examined intraepithelial lymphocytes (IELs) in 213 ileal biopsies from 16 bowel grafts and compared them with 32 biopsies from native intestines. During the first year posttransplantation, grafts exhibited low levels of IELs (percentage of CD103(+) cells) principally due to reduced CD3(+) CD8(+) cells, while CD103(+) CD3(-) cell numbers became significantly higher. Changes in IEL subsets did not correlate with histology results, isolated intestine, or multivisceral transplants, but CD3(-) IELs were significantly higher in patients receiving corticosteroids. Compared with controls, more CD3(-) IELs of the grafts expressed CD56, NKp44, interleukin (IL)-23 receptor, retinoid-related orphan receptor gamma t (RORγt), and CCR6. No difference was observed in granzyme B, and CD3(-) CD127(+) cells were more abundant in native intestines. Ex vivo, and after in vitro activation, CD3(-) IELs in grafts produced significantly more interferon (IFN)-γ and IL-22, and a double IFNγ(+) IL-22(+) population was observed. Epithelial cell-depleted grafts IELs were cytotoxic, whereas this was not observed in controls. In conclusion, different from native intestines, a CD3(-) IEL subset predominates in grafts, showing features of natural killer cells and intraepithelial ILC1 (CD56(+) , NKp44(+) , CCR6(+) , CD127(-) , cytotoxicity, and IFNγ secretion), ILC3 (CD56(+) , NKp44(+) , IL-23R(+) , CCR6(+) , RORγt(+) , and IL-22 secretion), and intermediate ILC1-ILC3 phenotypes (IFNγ(+) IL-22(+) ). Viability of intestinal grafts may depend on the balance among proinflammatory and homeostatic roles of ILC subsets.

Luminescence-based assay to screen preservation solutions for optimal ability to maintain viability of rat intestinal grafts

BACKGROUND

Segmental intestinal transplantations from living, genetically related donors provide advantages compared with those from cadaveric subjects. However, successful preservation during ischemic cold storage is critical for living donor grafts. Thus, the development of preservation solutions that maintain graft viability is essential for success. Herein we have reported application of a cell-based viability assay in multiwell plates to assess the effectiveness of various solutions to preserve intestinal grafts.

METHODS

Freshly isolated intestinal chips from luciferase transgenic rats were placed in 96-well tissue culture plates for incubation at 4°C for 24 hours in various preservation solutions: ET-Kyoto (ET-K), University of Wisconsin (UW) solution, Euro-Collins (EC) solution, histidine-tryptophan-ketoglutarate (HTK) solution, lactated Ringer's (LR) solution, or saline.

RESULTS

As indicated by a higher level of luminescence, intestinal chips preserved in UW, HTK, or ET-K solution contained more viable cells, than those preserved in EC, LR, or saline solution. After exposure to the preservation solutions for 1 hour, the mucosal layer chips showed lower cell viability than the muscle layer chips.

CONCLUSION

Our data demonstrated that ET-K and UW solutions used together with intestinal chips of Luciferase transgenic rat and in vivo imaging provided optimal viability during ischemic cold storage prior to transplantation. Further development of preservation conditions to minimize the loss of viability of intestinal grafts before clinical transplantation is essential to improve outcomes.

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.

Adoptive infusion of tolerance dendritic cells prolongs survival of small intestine allografts in rats: systematic review and meta-analysis

BACKGROUND

Postoperative infections and rejection are the main limiting factors of small intestine allograft survival. In this study, we performed a systematic review and meta-analysis to review rat small intestine allograft survival following infusion of tolerance dendritic cells (Tol-DCs) induced by different methods.

METHODS

Relevant publications were searched from PubMed database and EMbase database. Meta-analysis was performed using RevMan 5.0 software. We chose allograft survival, mixed leukocyte reaction, Th1/Th2 differentiation, Treg induction, and cytotoxic T lymphocyte activity as the outcomes by which to examine possible mechanisms that promote survival.

RESULTS

Eleven suitable articles were identified and assessed. Tol-DCs induced by four methods all prolonged allograft survival. The difference in survival time between the Tol-DC group and the control group was indicated by SMD as follows: drug intervention (SMD = 3.02, 95% CI 1.16 to 4.88, P = 0.001), gene modification (SMD = 2.43, 95% CI 1.77 to 3.10, P < 0.00001), imDC (SMD = 1.76, 95% CI 0.90 to 2.62, P < 0.0001), cytokine induction (SMD = 1.68, 95% CI 0.40 to 2.96, P = 0.01). Tol-DCs were also synergistic with immunosuppressive drugs or costimulation inhibitors, but no immune tolerance was observed. A single-dose intravenous injection of 5×10(6) to 6×10(6) Tol-DCs showed the highest allograft survival. Possible mechanisms included donor-specific T-cell hyporesponsiveness and Th2 differentiation.

CONCLUSIONS

Our results demonstrated that Tol-DCs induced by four methods prolong rat small intestine allograft survival. Intravenous infusion of 5×10(6) to 6×10(6) Tol-DCs was the optimum dose in rat small intestine transplantation. Immunosuppressive or costimulatory blockade was synergistic with Tol-DC on graft survival. Additional high-quality studies with larger sample sizes are needed to better investigate small intestinal graft longer term survival.

Assessment of abnormal bowel perfusion using contrast-enhanced ultrasonography after small bowel transplantation: a case report

A 59-year-old man with short-bowel syndrome received a small bowel transplantation. Because the recipient complained of severe abdominal pain 40 hours after the surgery and was highly suspected of having mesenteric vascular thrombosis, contrast-enhanced sonography (CEUS) was performed at his bedside. CEUS demonstrated that the superior mesenteric artery was patent, but the bowel graft showed hypoenhancement, indicating severely inadequate perfusion of the graft. Due to this complication, the patient underwent an exploratory laporatomy, and the bowel graft was removed. The pathologic findings support the diagnosis of acute vascular rejection after intestinal transplantation. This case suggests that CEUS can be used to assess perfusion and vascular complications after intestinal transplantation, as it is noninvasive and easily performed at bedside.

Indications for intestinal transplantation: recognizing the scope and limits of total parenteral nutrition

Total parenteral nutrition (TPN) is currently the treatment of choice for patients with intestinal failure. Intestinal failure in adults is mostly due to short bowel syndrome, which is most often caused by ischemia and Crohn's disease. However, TPN fails in a substantial number of cases. For patients with TPN failure, intestinal transplantation (ITx) may be offered as a treatment. TPN failure is considered to be present either if nutrition itself is not possible or if complications of TPN occur. These complications can, for example, originate from recurrent line infections or thrombosis. As TPN is usually a lifelong therapy and is associated with substantial impairment of the quality of life, the tolerance of each patient to this procedure is another important consideration in the decision making about whether to perform transplantation. The survival rates of intestinal transplant recipients have now reached the same level as that of recipients of other solid organ transplants. A five-yr survival of up to 80% has been reported in specialized centers, whereas registry data show rates of <80%. Although in about one-third of patients, isolated ITx is sufficient, patients with concurrent liver disease (mostly due to TPN) benefit from combined intestinal and liver transplantation. In some cases, multivisceral transplantation is necessary. Here, we review the current indications for ITx with a special focus on TPN.

Function and expression of cystic fibrosis transmembrane conductance regulator after small intestinal transplantation in mice

The secretion function of intestinal graft is one of the most important factors for successful intestinal transplantation. Cystic fibrosis transmembrane conductance regulator (CFTR) mediates HCO₃^- and Cl^- secretions in intestinal epithelial cells. In this study, we made investigation on the expression and function of CFTR in an experimental model of murine small intestinal transplantation. Heterotopic intestinal transplantations were performed in syngeneic mice. The mRNA and protein expressions of CFTR were analyzed by real time PCR and western blot. Murine intestinal mucosal HCO₃^- and Cl^- secretions were examined in vitro in Ussing chambers by the pH stat and short circuit current (I_sc) techniques. The results showed that forskolin, an activator of CFTR, stimulated jejunal mucosal epithelial HCO₃^- and Cl^- secretions in mice, but forskolin-stimulated HCO₃^- and Cl^- secretions in donor and recipient jejunal mucosae of mice after heterotopic jejunal transplantation were markedly decreased, compared with controls (P<0.001). The mRNA and protein expression levels of CFTR in donor and recipient jejunal mucosae of mice were also markedly lower than those in controls (P<0.001), and the mRNA and protein expression levels of tumor necrosis factor α (TNFα) were markedly increased in donor jejunal mucosae of mice (P<0.001), compared with controls. Further experiments showed that TNFα down-regulated the expression of CFTR mRNA in murine jejunal mucosa. In conclusion, after intestinal transplantation, the function of CFTR was impaired, and its mRNA and protein expressions were down-regulated, which may be induced by TNFα.

Tissue engineering the small intestine

Short bowel syndrome (SBS) results from the loss of a highly specialized organ, the small intestine. SBS and its current treatments are associated with high morbidity and mortality. Production of tissue-engineered small intestine (TESI) from the patient's own cells could restore normal intestinal function via autologous transplantation. Improved understanding of intestinal stem cells and their niche have been coupled with advances in tissue engineering techniques. Originally described by Vacanti et al of Massachusetts General Hospital, TESI has been produced by in vivo implantation of organoid units. Organoid units are multicellular clusters of epithelium and mesenchyme that may be harvested from native intestine. These clusters are loaded onto a scaffold and implanted into the host omentum. The scaffold provides physical support that permits angiogenesis and vasculogenesis of the developing tissue. After a period of 4 weeks, histologic analyses confirm the similarity of TESI to native intestine. TESI contains a differentiated epithelium, mesenchyme, blood vessels, muscle, and nerve components. To date, similar experiments have proved successful in rat, mouse, and pig models. Additional experiments have shown clinical improvement and rescue of SBS rats after implantation of TESI. In comparison with the group that underwent massive enterectomy alone, rats that had surgical anastomosis of TESI to their shortened intestine showed improvement in postoperative weight gain and serum B12 values. Recently, organoid units have been harvested from human intestinal samples and successfully grown into TESI by using an immunodeficient mouse host. Current TESI production yields approximately 3 times the number of cells initially implanted, but improvements in the scaffold and blood supply are being developed in efforts to increase TESI size. Exciting new techniques in stem cell biology and directed cellular differentiation may generate additional sources of autologous intestinal tissue for direct translation to human therapy.

Segmental reversal of the small bowel can end permanent parenteral nutrition dependency: an experience of 38 adults with short bowel syndrome

OBJECTIVE

This study aimed to assess the results of segmental reversal of the small bowel (SRSB) in patients with short bowel syndrome (SBS) who were "permanently" dependent on parenteral nutrition (PN) and to identify possible prognostic factors for weaning.

SUMMARY BACKGROUND DATA

SRSB is a nontransplant surgical option for patients with SBS who require long-term PN. Few studies have reported outcomes in humans.

METHODS

: All patients who were permanently dependent on PN and underwent a SRSB between 1985 and 2010 for SBS were included. The data were retrospectively retrieved.

RESULTS

Thirty-eight patients underwent SRSB. The median age was 55.5 years (range, 18-76). The median length of the small bowel remnant was 49 cm (20-140), including a reversed segment of 10 cm (6-15). The median follow-up was 57.7 months (1-304). At the 5-year follow-up, 17 patients had been weaned from PN (45%). In the remaining patients, PN dependency had decreased from 7 ± 1 to 4 ± 1 days per week. The survival rate was 84%. The prognostic factors for weaning were a short time between subtotal enterectomy and SRSB (P = 0.036), a longer than typical stay in the nutrition unit (P = 0.035), and an SRSB longer than 10 cm (P = 0.024).

CONCLUSIONS

SRSB has a role as a conservative alternative to small bowel transplantation in patients with SBS permanently dependent on PN. With a segmental reversal of 10 to 12 cm, almost half of the patients can be expected to be weaned from PN.

Human tissue-engineered small intestine forms from postnatal progenitor cells

PURPOSE

Tissue-engineered small intestine (TESI) represents a potential cure for short bowel syndrome (SBS). We previously reported full-thickness intestine formation using an organoid units-on-scaffold approach in rodent and swine models. Transplanted intestinal xenografts have been documented to survive from human fetal tissue but not from postnatal tissue. We now present the first report of human TESI from postnatal tissue.

METHODS

Organoid units (OU) were prepared from human small bowel resection specimens, loaded onto biodegradable scaffolds and implanted into NOD/SCID gamma chain-deficient mice. After 4 weeks, TESI was harvested and immunostained for β2-microglobulin to identify human tissue, villin for enterocytes, lysozyme for Paneth cells, chromogranin-A for enteroendocrine cells, mucin-2 for goblet cells, smooth muscle actin and desmin to demonstrate muscularis, and S-100 for nerves.

RESULTS

All TESI was of human origin. Immunofluorescence staining of human TESI reveals the presence of all four differentiated cell types of mature human small intestine, in addition to the muscularis and the supporting intestinal subepithelial myofibroblasts. Nerve tissue is also present.

CONCLUSIONS

Our technique demonstrates survival, growth, and differentiation of postnatally derived human small intestinal OU into full thickness TESI in murine hosts. This regenerative medicine strategy may eventually assist in the treatment of SBS.

Intestinal transplantation: indications and prospects

Intestinal transplantation (IT) can involve small bowel transplantation alone, or be associated with liver or multivisceral transplantation. Although IT is the radical treatment for intestinal failure, home parenteral nutrition (PN) remains the treatment of choice for this disease. Indications for IT are still debated. A recent study showed that early referral for IT is recommended for patients with life-threatening combined liver and intestinal failure or for patients with invasive intra-abdominal desmoid tumors. In the same study, no survival benefit was shown for patients undergoing IT for ultra-short bowel or major complications related to the PN catheter; indications still need to be fully assessed. While short-term outcomes for IT have improved dramatically (one-year survival for small bowel-alone IT is now 80% versus 0-28% in the 1980s), long-term outcomes have not improved much since the introduction of Tacrolimus in the 1990s: five-year survival still does not exceed 60%. Some prospective developments could improve these results: the use of multivisceral grafts, the use of Sirolimus and Thymoglobulins in the immunosuppressive treatment, or the use of new biochemical markers for early diagnosis of graft rejection.

Portal hypertension after combined liver and intestinal transplantation, a diagnostic and therapeutic challenge?

A widely accepted technique to transplant the liver-bowel bloc is first to perform a piggyback anastomosis of the donor suprahepatic vena cava to the recipient vena cava; second to restore the arterial blood supply through an aortic interposition graft; and third to ensure venous drainage of the native foregut. The venous drainage of the native foregut can be restored through an end-to-end portocaval anastomosis between the donor infrahepatic vena cava and the recipient portal vein. Stenosis of this anastomosis can lead to portal hypertension presenting with upper GI congestion, bleeding, and hypersplenism. We report the successful treatment of this complication using an e-PTFE-covered stent inserted following balloon angioplasty.

The pig as a preclinical model for intestinal ischemia-reperfusion and transplantation studies

Small bowel transplantation has become an established procedure for treatment of irreversible intestinal failure. In this procedure, primary ischemia and reperfusion is inevitable and will lead to some level of tissue injury. Both clinical and experimental data demonstrate that events occurring at the time of transplantation, called ischemia reperfusion injury (IRI), may have deleterious short- and long-term effects, manifesting as increased episodes of acute rejection and chronic allograft dysfunction. Recently, the acute phase of IRI has been increasingly viewed as part of the innate immune response to the lack of vascular perfusion and oxygen. Research on intestinal IRI that aims to understand its mechanisms and the means to reduce its impact on morbidity and mortality related to intestinal transplantations is considered important because a link has been suggested between innate immunity, adaptive immune responses and organ regeneration, and thus long-term graft function. This article provides an overview of porcine models commonly used to study intestinal reperfusion injury and to evaluate intestinal transplant protocols. It also updates the current knowledge obtained from this model, establishing the pig as a reference standard in intestinal transplantation research.

Living donor intestinal transplant using a standardized technique: first report from India

AIM

We describe the first living donor intestinal transplant (LDIT) in India and discuss the indications and problems of this complex procedure.

METHODS

A 43-year-old male patient required massive bowel resection for gangrene due to thrombosis of the superior mesenteric artery. He was maintained on parenteral nutrition but developed cholestasis and well as repeated catheter related infections with progressive loss of venous access due to thrombosis of central veins. A LDIT was performed using 200 cm of small intestine from the patient's son. The graft was based on the continuation of the superior mesenteric vessels beyond the ileocolic branch. The artery was anastomosed directly to the aorta and the vein to the venacava.

RESULTS

The graft functioned well and he was weaned off parenteral nutrition. However, he later developed complications (wound dehiscence and enterocutaneous fistula) and developed sepsis. He succumbed to sepsis with a functioning graft 6 weeks after the transplant. The donor recovered uneventfully and was discharged on the 4th postoperative day.

CONCLUSIONS

LDIT can be life saving in patients with intestinal failure and failure of parenteral nutrition. There is a need to introduce this modality in India. In a setting of scarcity of deceased donor organs the living donor option has advantages.

Generating intestinal tissue from stem cells: potential for research and therapy

Intestinal resection and malformations in adult and pediatric patients result in devastating consequences. Unfortunately, allogeneic transplantation of intestinal tissue into patients has not been met with the same measure of success as the transplantation of other organs. Attempts to engineer intestinal tissue in vitro include disaggregation of adult rat intestine into subunits called organoids, harvesting native adult stem cells from mouse intestine and spontaneous generation of intestinal tissue from embryoid bodies. Recently, by utilizing principles gained from the study of developmental biology, human pluripotent stem cells have been demonstrated to be capable of directed differentiation into intestinal tissue in vitro. Pluripotent stem cells offer a unique and promising means to generate intestinal tissue for the purposes of modeling intestinal disease, understanding embryonic development and providing a source of material for therapeutic transplantation.

Progress in abdominal organ transplantation

The excellent results of vascularized organ transplantation have resulted in an increasing number of end-stage organ failure patients seeking such treatment. The results of organ transplantation depend on a number of factors – the quality of the donor (and an organ), living vs. deceased donation, magnitude of ischemic injury (and its prevention), and recipient-dependent factors. Ischemia/reperfusion injury in organ transplantation is a multifactorial process, which may lead to delayed graft function. In addition, surgical and preservation techniques, type of immunosuppressive regimens, complications after transplantation and post-transplant management may also have a significant impact on short- and long-term results of transplantation. In this paper we describe advances in transplantation in recent years, with particular emphasis on kidney, liver, intestines, whole pancreas and pancreatic islets.

Effect of polyethylene glycol in pig intestinal allotransplantation without immunosuppression

OBJECTIVES

We evaluated whether IGL-1, a graft preservation solution containing polyethylene glycol, improves the outcome of small bowel grafts in comparison to the University of Wisconsin (UW) solution in a pig allotransplantation model.

MATERIALS AND METHODS

Seventeen pigs were randomly allocated to group 1 (n = 10; intestinal allotransplantation with IGL-1) and group 2 (n = 7; allotransplantation with UW). Pigs received no immunosuppression and were sacrificed on postoperative d (POD) 8. Intestinal specimens were obtained from the animal immediately before cold flushing (T0), 2 h after graft reperfusion (T1), and at sacrifice (T2).

RESULTS

Survival rate to POD 8 was 50% in group 1 compared with 16% in group 2 (P < 0.05); 62% of pigs in group 1 did not present any acute cellular rejection (ACR) compared to 16% in group 2 (P < 0.05). Severe ACR rate was 25% in group 1 and 66% in group 2 (P < 0.05). iNOS activity and intestinal caspase 3 levels increased significantly between T0 and T1 in group 1 compared to group 2 (P < 0.05). Cell necrosis increased significantly between TO and T1 in group 2 compared with group 1 (P < 0.05) whereas cell apoptosis was significantly higher at T1 compared with T0 in group 1 in comparison to group 2.

CONCLUSIONS

Our results show that IGL-1 improves intestinal graft viability as compared to UW solution, possibly by reducing graft immunogenicity and by favoring intestinal epithelial repair.

Perioperative infliximab application has marginal effects on ischemia-reperfusion injury in experimental small bowel transplantation in rats

PURPOSE

Ischemia-reperfusion injury leads to impaired smooth muscle function and inflammatory reactions after intestinal transplantation. In previous studies, infliximab has been shown to effectively protect allogenic intestinal grafts in the early phase after transplantation with resulting improved contractility. This study was designed to reveal protective effects of infliximab on ischemia-reperfusion injury in isogenic transplantation.

METHODS

Isogenic, orthotopic small bowel transplantation was performed in Lewis rats (3 h cold ischemia). Five groups were defined: non-transplanted animals with no treatment (group 1), isogenic transplanted animals with vehicle treatment (groups 2/3) or with infliximab treatment (5 mg/kg body weight intravenously, directly after reperfusion; groups 4/5). The treated animals were sacrificed after 3 (group 2/4) or 24 h (group 3/5). Histological and immunohistochemical analysis, TUNEL staining, real-time RT-PCR, and contractility measurements in a standard organ bath were used for determination of ischemia-reperfusion injury.

RESULTS

All transplanted animals showed reduced smooth muscle function, while no significant advantage of infliximab treatment was observed. Reduced infiltration of neutrophils was noted in the early phase in animals treated with infliximab. The structural integrity of the bowel and infiltration of ED1-positive monocytes and macrophages did not improve with infliximab treatment. At 3 h after reperfusion, mRNA expression of interleukin (IL)-6, TNF-α, IL-10, and iNOS and MCP-1 displayed increased activation in the infliximab group.

CONCLUSION

The protective effects of infliximab in the early phase after experimental small bowel transplantation seem to be unrelated to ischemia-reperfusion injury. The promising effects in allogenic transplantation indicate the need for further experiments with infliximab as complementary treatment under standard immunosuppressive therapy. Further experiments should focus on additional infliximab treatment in the setting of acute rejection.