Duodenal histology for monitoring treatment of acute rejection in pancreaticoduodenal allografts in rats

Banff 2022 pancreas transplantation multidisciplinary report: Refinement of guidelines for T cell-mediated rejection, antibody-mediated rejection and islet pathology. Assessment of duodenal cuff biopsies and noninvasive diagnostic methods

The Banff pancreas working schema for diagnosis and grading of rejection is widely used for treatment guidance and risk stratification in centers that perform pancreas allograft biopsies. Since the last update, various studies have provided additional insight regarding the application of the schema and enhanced our understanding of additional clinicopathologic entities. This update aims to clarify terminology and lesion description for T cell-mediated and antibody-mediated allograft rejections, in both active and chronic forms. In addition, morphologic and immunohistochemical tools are described to help distinguish rejection from nonrejection pathologies. For the first time, a clinicopathologic approach to islet pathology in the early and late posttransplant periods is discussed. This update also includes a discussion and recommendations on the utilization of endoscopic duodenal donor cuff biopsies as surrogates for pancreas biopsies in various clinical settings. Finally, an analysis and recommendations on the use of donor-derived cell-free DNA for monitoring pancreas graft recipients are provided. This multidisciplinary effort assesses the current role of pancreas allograft biopsies and offers practical guidelines that can be helpful to pancreas transplant practitioners as well as experienced pathologists and pathologists in training.

A comprehensive update of the metabolic and toxicological considerations for immunosuppressive drugs used during pancreas transplantation

INTRODUCTION

Despite significant advancements in immunosuppressive regimens and surgical techniques, the prevalence of adverse events related to immunosuppression remains a major challenge affecting the long-term survival rates of pancreas and kidney allografts.

AREAS COVERED

This article presents a comprehensive review of the literature and knowledge (Jan/2012-Feb/2023) concerning glucose metabolism disorders and nephrotoxicity associated with tacrolimus and mammalian target of rapamycin inhibitors (mTORi). Novel signaling pathways potentially implicated in these adverse events are discussed. Furthermore, we extensively examine the findings from clinical trials evaluating the efficacy and safety of tacrolimus, mTORi, and steroid minimization.

EXPERT OPINION

Tacrolimus-based regimens continue to be the standard treatment following pancreas transplants. However, prolonged use of tacrolimus and mTORi may lead to hyperglycemia and nephrotoxicity. Understanding and interpreting experimental data, particularly concerning novel signaling pathways beyond calcineurin-NFAT and mTOR pathways, can offer valuable insights for therapeutic interventions to mitigate hyperglycemia and nephrotoxicity. Additionally, critically analyzing clinical trial results can identify opportunities for personalized safety-based approaches to minimize side effects. It is imperative to conduct randomized-controlled studies to assess the impact of mTORi use and steroid-free protocols on pancreatic allograft survival. Such studies will aid in tailoring treatment strategies for improved transplant outcomes.

Endoscopic visualization of graft status in patients with pancreas transplantation

BACKGROUND

Enteric drainage into the recipient duodenum in pancreas transplantation (PT) can identify the graft duodenum by endoscopy. This study aimed to identify the characteristic endoscopic findings associated with graft failure or acute rejection in patients with PT.

METHODS

We reviewed the medical records of patients who underwent PT with duodenoduodenostomy (DD) between January 2015 and August 2019. During this period, there were 44 PTs with DD in 42 patients; 122 endoscopies were performed and analyzed.

RESULTS

Overall, pancreatic graft survival was 82% at a mean follow-up of 27 months (range 6-55 months). There were 8 graft failures and 10 acute rejections. In all 8 graft failures, a deep ulcer covered with fibrinous exudates of the graft duodenum was confirmed on endoscopy. Diffuse erythema inside the graft duodenum was observed in 8 of 10 acute rejections. The factors associated with acute rejection were elevated serum lipase level (OR 8.5, p = 0.02) and diffuse erythema inside the graft duodenum on endoscopy (OR 20.5, p < 0.01) in multivariate analysis.

CONCLUSIONS

In PT with DD patients, graft failure can be visualized by endoscopy, and diffuse erythema inside the graft duodenum may be a finding of acute rejection.

In vivo endomicroscopy of donor duodenum improves early detection of pancreas rejection in a recipient of simultaneous duodenum-drained pancreas-kidney transplantation: a case report

Confocal laser endomicroscopy (CLE) is a new technique, which allows subsurface histological diagnosis at a cellular and subcellular level in vivo and could provide histological diagnosis during endoscopic examination. Up to now histological examination of the tissue sample is the only definitive way of diagnosis and monitoring organ rejection after transplantation. In case of pancreas transplantation percutaneous pancreas biopsy under imaging control is still the method of choice for obtaining tissue samples. However in 73–89% of biopsy attempts, it was shown that the duodenal histology predicts the initial diagnosis of rejection of the pancreas, usefulness of transplanted duodenum biopsies for graft rejection monitoring was also described. The histology technique is time consuming, and the therapeutic decision could not be made quickly, in spite of clinical necessity. In this paper we described feasibility of visualization and biopsy of donor duodenum and detection of microscopic changes in 2 cases of transplanted duodenum, expressed as destruction of the villi and dispersed goblet cells in comparison to a microscopic view of their own healthy duodenum No or only small, endoscopically non-significant macroscopic changes in transplanted duodenum in those patients were observed. In both cases, the histological examination confirmed acute organ rejection. We demonstrated for the first time that CLE is promising and effective method to detect acute phase of organ rejection and also for follow up in those patients.

Enteroscopic biopsies in the management of pancreas transplants: a proof of concept study for a novel monitoring tool

BACKGROUND

Although percutaneous biopsies are considered to be the gold standard in diagnosing pancreas graft rejection, they are not performed routinely because of their association with severe complications. On the other hand, correct diagnosis of rejection is essential but may be difficult in cases of enteric drainage, particularly in patients with a pancreas transplant alone or a pancreas after kidney transplant.

METHODS

Pancreas recipients who underwent enteroscopy between May 2005 and September 2009 were included in this retrospective analysis. Biopsies were graded 0 to 4 for interstitial and vascular changes.

RESULTS

During the study period a total of 65 simultaneous pancreas-kidney transplants, 13 pancreas after kidney transplants and 4 pancreas transplants alone were performed. Sixty-three patients underwent a single enteroscopy, 10 had two, and 6 had three or more. Indications were protocol graft monitoring (n=73), graft dysfunction (n=17), enteric hemorrhage (n=9), or other (n=3). The duodenal segment was accessed in 76 instances (75%) with abnormal findings in 23. A total of 69 biopsies were obtained and revealed normal mucosa in 49 cases (71%). Histology showed signs of acute rejection in 11 cases. The upper gastrointestinal tract was also assessed, and, in 13 cases, additional pathologies were identified including gastroduodenitis (n=10), gastric/duodenal ulcer (n=2), and hemorrhagic esophagitis (n=1). No procedure-related complication occurred.

CONCLUSIONS

This series of enteroscopies demonstrates that the duodenal segment of a pancreatic graft is accessible using our implant technique, and thus permitting biopsies to be obtained and endoscopic interventions to be performed.