Posttransplant complications in adult recipients of intestine grafts without bowel decontamination

Intestinal and Multivisceral Transplantation: Complications

Advancements in immunosuppression protocols, surgical techniques, and postoperative care in the last few decades have improved outcomes of intestinal transplant patients. Normal immediate postoperative imaging appearance can simulate pathology. Intestinal transplant recipients are prone for several postoperative complications due to the complex surgical technique, which involves multiple anastomoses, and immunogenic nature of the allograft intestine. Imaging plays a crucial role in detection of several major complications including infectious, immunologic, vascular, gastrointestinal, pancreaticobiliary, genitourinary, and neoplastic complications. The awareness of the posttransplant anatomy and normal imaging appearances helps radiologists anticipate and accurately detect posttransplant complications.

Intestinal Transplant Immunology and Intestinal Graft Rejection: From Basic Mechanisms to Potential Biomarkers

Intestinal transplantation (ITx) remains a lifesaving option for patients suffering from irreversible intestinal failure and complications from total parenteral nutrition. Since its inception, it became obvious that intestinal grafts are highly immunogenic, due to their high lymphoid load, the abundance in epithelial cells and constant exposure to external antigens and microbiota. This combination of factors and several redundant effector pathways makes ITx immunobiology unique. To this complex immunologic situation, which leads to the highest rate of rejection among solid organs (>40%), there is added the lack of reliable non-invasive biomarkers, which would allow for frequent, convenient and reliable rejection surveillance. Numerous assays, of which several were previously used in inflammatory bowel disease, have been tested after ITx, but none have shown sufficient sensibility and/or specificity to be used alone for diagnosing acute rejection. Herein, we review and integrate the mechanistic aspects of graft rejection with the current knowledge of ITx immunobiology and summarize the quest for a noninvasive biomarker of rejection.

Luminal polyethylene glycol solution delays the onset of preservation injury in the human intestine

The organ damage incurred during the cold storage (CS) of intestinal grafts has short and long-term consequences. Animal studies suggest that additional luminal preservation (LP) with polyethylene glycol (PEG) may alleviate this damage. This study aims to validate these findings using human intestines. Ileal segments, perfused intravascularly with IGL-1 solution, were procured from 32 multiorgan donors and divided into two parts: one containing a PEG 3350-based solution introduced luminally (LP group) and another one without luminal treatment (control). Sampling was performed after 4 h, 8 h, 14 h, and 24 h of CS. Histology was assessed using the Chiu/Park score. Tight junctions (TJ), several inflammatory markers, and transcription factors were examined by immunofluorescence, ddPCR, and western blot. Tissue water content (edema) was also measured. Apoptotic activity was assessed with caspase -2, -3, and -9 assays. LP significantly lowered mucosal injury at all time points. Redistribution of TJ proteins occurred earlier and more severely in the control group. After 24 h of CS, LP intestines showed an emerging unfolding protein response. Increased caspase-3 and -9 activity was found in the control group. The current results indicate that luminal PEG is safe and effective in reducing damage to the intestinal epithelium during CS.

Preemptive VAE-An Important Tool for Managing Blood Loss in MVT Candidates With PMT

Explantation of native viscera in multivisceral transplant candidates, particularly in those with extensive portomesenteric thrombosis (PMT), carries considerable morbidity due to extensive vascularized adhesions. Preemptive visceral angioembolization has been previously described as a technique to minimize excessive blood loss during mobilization of the native viscera but is not well described specifically in patients with extensive PMT.

Intestinal Preservation Injury: A Comparison Between Rat, Porcine and Human Intestines

Advanced preservation injury (PI) after intestinal transplantation has deleterious short- and long-term effects and constitutes a major research topic. Logistics and costs favor rodent studies, whereas clinical translation mandates studies in larger animals or using human material. Despite diverging reports, no direct comparison between the development of intestinal PI in rats, pigs, and humans is available. We compared the development of PI in rat, porcine, and human intestines. Intestinal procurement and cold storage (CS) using histidine-tryptophan-ketoglutarate solution was performed in rats, pigs, and humans. Tissue samples were obtained after 8, 14, and 24 h of CS), and PI was assessed morphologically and at the molecular level (cleaved caspase-3, zonula occludens, claudin-3 and 4, tricellulin, occludin, cytokeratin-8) using immunohistochemistry and Western blot. Intestinal PI developed slower in pigs compared to rats and humans. Tissue injury and apoptosis were significantly higher in rats. Tight junction proteins showed quantitative and qualitative changes differing between species. Significant interspecies differences exist between rats, pigs, and humans regarding intestinal PI progression at tissue and molecular levels. These differences should be taken into account both with regards to study design and the interpretation of findings when relating them to the clinical setting.

Post-intestine transplant graft-vs-host disease associated with inclusion of a liver graft and with a high mortality risk

INTRODUCTION

This study reports the incidence, anatomic location, and outcomes of graft-vs-host disease (GVHD) at a single active intestine transplant center.

METHODS

Records were reviewed for all patients receiving an intestine transplant from 2003 to 2015. Pathology reports and pharmacy records were reviewed to establish the diagnosis, location, and therapeutic interventions for GVHD.

RESULTS

A total of 236 intestine transplants were performed during the study period, with 37 patients (16%) developing GVHD. The median time to onset of disease was 83 days, with 89% of affected patients diagnosed in the first year post-transplant. Mortality for affected patients was 54% in the 1 year after GVHD diagnosis. Skin lesions were the most common manifestation of GVHD. Other sites of disease included lungs, bone marrow, oral mucosa, large intestine, and brain. The incidence of GVHD was 16% in adult patients, and slightly lower in pediatric recipients (13%). In adults, increasing graft volume (isolated vs multi-organ) and liver inclusion were associated with increasing risk of GVHD, though this was not seen in pediatric patients.

CONCLUSION

Overall, 16% of intestine transplant recipients developed GVHD. GVHD is associated with high mortality, and disease in the lungs, brain, and bone marrow was universally fatal.