Increase in mortality rate of liver transplant candidates residing in specific geographic areas: analysis of UNOS data.

We sought to evaluate survival of liver transplant candidates living in geographic areas with limited access to specialized transplant centers (TxC). We analyzed survival outcome among candidates listed for liver transplant in United Network of Organ Sharing (UNOS) Region 4 from 2004 to 2010. Candidates were stratified into three groups according to the distance from the patient's residence to the closest hospital with a liver transplant program: Group 1 (Gr 1) <30 miles (m), Group 2 (Gr 2) 30-60 m and Group 3 (Gr 3) >60 m. Of the 5673 patients included in the study, 49% resided >30 m from a TxC. Eight percent of the cohort experienced death or dropped out of the list due to medical condition deterioration, with worse outcomes for Gr 2 and Gr 3 (8.5% and 9.9%, respectively, vs. 6.5% for Gr 1 [p < 0.001]). Among patients with a MELD score <20, mortality was higher in Gr 2 and Gr 3 compared to Gr 1 (p < 0.001). We conclude that for Region 4, the mortality risk in patients living >30 m from a TxC is higher. We suggest that the variable "distance from a TxC" should be used to improve the estimate of the mortality risk for patients on the waiting list.

Magnification endoscopy as a reliable tool for the early diagnosis of rejection in living related small bowel transplants: a case report.

The purpose was to determine whether magnification endoscopy (ME) accurately diagnosed rejection in living related small bowel transplants (LRSBTx) during initial morphological adaptation of segmental intestinal grafts. The small bowel recipient was a 44-year-old woman with short gut syndrome following multiple bowel surgeries for familial adenomatous polyposis. ME was enhanced by chromoendoscopy staining. Bowel mucosa was washed with acetic acid and stained with methylene blue for optimal visualization of mucosal villi and to improve the diagnostic yield of biopsies. The recipient underwent surveillance ME with biopsy 16 times through the ileostomy in the first 9 months following transplantation. The recipient developed diarrhea in the postoperative course, which led to the suspicion of rejection. ME findings of patchy villus blunting were consistent with biopsy samples that showed mild acute cellular rejection. Episodes of rejection were treated with high-dose immunosuppressants and steroids. Reversal of rejection was monitored by follow-up ME, which showed increased length of villi and normalization of morphology. Biopsy confirmed these findings. The first endoscopy, at 5 days posttransplant, showed no evidence of intestinal ischemia. LRSBTx involves early morphological adaptation of the recipient small bowel mucosa, characterized by an increased length of villi. ME is a reliable technique to follow adaptation and detect early rejection. The superior imaging of small bowel mucosa created by ME chromoendoscopy enables early diagnosis and delivery of more prompt antirejection therapy to prevent progression of rejection. ME also confirmed that segmental LRSBTx caused minimal ischemic injury to the recipient.

Intragraft gene expression profile during acute cellular rejection in clinical small bowel transplantation: a case report.

BACKGROUND: Acute cellular rejection (ACR) is a common complication of small bowel transplantation (SBTx) and the major cause of graft loss. However, little is known regarding the genetic graft response to ACR in clinical transplants. In this study, we have determined a genetic expression profile of intestinal graft response to ACR after living related (LR) SBTx. RESULTS: By identifying the expression profiles of reported markers of rejection we were able to identify 57 genes that had significantly increased (more than twofold) expression in response to ACR. Known markers of rejection identified: MMP-9, MMP-2, VIP, IFNgamma, IL-2R, MADCAM-1, HSP-60, and HSP-70 all had greater than twofold increased expression after ACR diagnosed (week 3 to week 6). The newly identified genes were: IFI27, EPST11, APAF1, LAP3, STK6, and MDK. CONCLUSION: Newly identified up-regulated genes in response to ACR in small bowel graft are involved in the immune response, cell adhesion, neurogenesis, cell division and proliferation, DNA replication/repair, protein ubiquitin/proteolysis, and apoptosis. TNFalpha up-regulated early at week 2 biopsy may be an early genetic marker of ACR in SBTx.

Gene expression profiles characterize early graft response in living donor small bowel transplantation: a case report.

BACKGROUND: The cellular and histological events that occur during the regeneration process in invertebrates have been studied in the field of visceral regeneration. We would like to explore the molecular aspects of the regeneration process in the small intestine. The aim of this study was to characterize the gene expression profiles of the intestinal graft to identify which genes may have a role in regeneration of graft tissue posttransplant. METHODS: In a patient undergoing living related small bowel transplantation (LRSBTx) in our institution, mucosal biopsies were obtained from the recipient intestine and donor graft at the time of transplant and at weeks 1, 2, 3, and 6 posttransplant. Total RNA was isolated from sample biopsies followed by gene expression profiles determined from the replicate samples (n = 3) for each biopsy using the Affymetrix U133 Plus 2.0 Human GeneChip set. RESULTS: Two profiles were obtained from the data. One profile showed rapid increase of 45 genes immediately after transplant by week 1 with significant changes (P < .05) greater than threefold including the chemokine CXC9 and glutathione-related stress factors, GPX2 and GSTA4. The second profile identified 133 genes that were significantly decreased by threefold or greater immediately after transplant week 1, including UCC1, the human homolog of the Ependymin gene. CONCLUSION: We have identified two gene expression profiles representing early graft responses to small bowel transplantation. These profiles will serve to identify and study those genes whose products may play a role in accelerating tissue regeneration following segmental LRSBTx.

Acellular dermal matrix provides a good option for abdominal wall closure following small bowel transplantation: a case report.

Following small bowel transplantation (SBTx), approximating the midline abdominal fascia can be problematic in patients with severely retracted abdominal cavities. We first report the use of acellular dermal matrix (ADM) for abdominal closure following living related SBTx. A 44-year-old woman with ultra-short gut syndrome secondary to multiple bowel resections received a 160-cm segmental intestinal graft from her daughter. The graft ileocolic vessels were anastomosed end to side to the inferior vena cava and distal aorta. A terminal ileostomy was fashioned because the patient had previous panproctocolectomy. The graft perfused well, and the laparotomy was primarily closed. On postoperative day 1, the patient required surgical exploration for evacuation of hematoma. Due to graft edema in a significantly retracted abdominal cavity, a 12x7 cm fascia defect was evident. Leaving the abdomen open or using a mesh was not entertained as options due to the high risk of infections. Primary closure under tension would also jeopardize the transplant, increasing the risk of thrombosis. The fascia defect was closed using a segment of ADM. The patient did well and went home on the postoperative day 11. At 2-year follow-up she is well and on oral diet without fascia defect or incisional hernia. This is the first report of the use of ADM for abdominal closure in patients receiving a SBTx. ADM is considered safe when used in contaminated sites and can allow primary closure of difficult wounds often seen in SBTx patients.

A novel approach for intestinal elongation using acellular dermal matrix: an experimental study in rats.

We tested the hypothesis that an anatomic scaffold placed in continuity with viable bowel might allow intestinal growth. Male ACI rats were used for the study. Acellular human dermis in the form of tubular scaffolds with an intraluminal diameter of approximately 0.3 cm was oriented with the luminal basement membrane and serosal dermal surface. The small bowel was transected approximately 2 cm distal to the ligament of Treitz. The graft was then anastomosed in continuity in group A (n = 5) or as a blind-ended pouch to a defunctionalized jejunal limb in group B (n = 8). The animals were sacrificed at various time points. Histology and immunohistochemistry were used to evaluate structural changes. Animals in group A developed peritonitis and were all sacrificed within the first week postoperatively. However, all animals in group B survived, increasing their body weight similarly to age-matched rats. Tissue samples obtained at sacrifice showed a progressively increasing amount of cellular infiltrate over time in the matrix. Epithelial regeneration, angioneogenesis, and myofibroblast infiltrate were seen at 2 weeks, while well-formed branching crypts were seen at 4 weeks. Intact mucosa extended across the anastomosis to the grafts at 6 months. This study demonstrated an anatomic scaffold of acellular matrix allowed mucosal regeneration from viable bowel placed in continuity. These findings set the basis for new intestinal elongation techniques.

Effect of perioperative antioxidant therapy on suboptimal islet transplantation in rats.

Islet transplantation success is limited by the posttransplant inflammatory response, and we are investigating the ability of antioxidants to neutralize this islet damage. We have shown that pyruvate can enhance the engraftment and functionality of a suboptimal islet mass in rats. The present study further investigated the effects of pyruvate, as well as the antioxidants vitamin E and vitamin C. In study A, 350 syngeneic islets were transplanted into the liver of chemically diabetic rats. Antioxidant treatment, or vehicle, was administered during the perioperative period and an intraperitoneal glucose tolerance test (IPGTT) was performed 2 months posttransplant. In study B, 500 syngeneic islets were transplanted under the kidney capsule of chemically diabetic rats. Antioxidant treatment was administered during the perioperative period. Islet-bearing kidney grafts were harvested 24, 48, and 96 hours posttransplant for histological study. Results revealed that pyruvate was the only significantly effective treatment in enhancing the engraftment and functionality of a suboptimal islet mass. Respectively, 56% and 80% of pyruvate-treated rats became normoglycemic after islet transplantation in study A and study B and had a normal insulin response to IPGTT. Histology results from the islet-bearing kidneys were inconclusive as to whether or not pyruvate has an antiapoptotic effect. We conclude that pyruvate, but not vitamin E or vitamin C, aids in the engraftment and functionality of a suboptimal islet mass with as much effectiveness as a full mass in this study. Further investigation into the mechanism of pyruvate protection is still warranted.

Successful incorporation of short-interfering RNA into islet cells by in situ perfusion.

UNLABELLED: Islet transplantation offers a potential cure for type I diabetes, although its success has been limited, due to loss of cells by apoptosis stimulated by the procurement, ischemia, and the isolation process itself. RNA interference (RNAi) as mediated by short interfering RNAs (siRNAs) has become a potent tool to manipulate gene expression in mammalian cells. We describe the first successful introduction of siRNA directly into pancreatic islet cells both during in situ perfusion and from intravenous tail vein injection (in vivo). METHODS: siRNA was targeted to the pancreatic islets of BALB/c mice by retrograde portal vein perfusion or tail vein injection. Cy3-labeled siRNA was dissolved in University of Wisconsin (UW) solution at 2 microg/mL. After delivery pancreata were placed in cold storage at 4 degrees C in UW solution for 24 hours, followed by processing for immunofluorescent staining for insulin. Fluorescent imaging was obtained using a Nikon DIAPHOT 300 Inverted Micoscope with a Zeiss AxioCam and OpenLab image capturing software. RESULTS: In situ delivery of siRNA was demonstrated by fluorescent imaging composites of (red) siRNA in and along (green) insulin stained islets from pancreas sections as compared with untreated control sections. The siRNA was detected mainly in and along venous structures throughout the pancreatic tissue. In vivo delivery of siRNA into islets was observed by fluorescent images taken of isolated islets in culture. CONCLUSIONS: We have described the successful delivery of siRNA to pancreatic islets via a novel in situ pancreas perfusion technique and in vivo delivery via tail vein injection.