Effect of liver histopathology on islet cell engraftment in the model mimicking autologous islet cell transplantation

Nutrition support in the pediatric total pancreatectomy with islet autotransplantation recipient

For children with diminished quality of life and chronic pain caused by acute recurrent or chronic pancreatitis who are undergoing total pancreatectomy with islet autotransplantation, postoperative nutrition support has several unique characteristics. Surgical complications may lead to delays in nutrition support initiation or require modifications to the regimen. Early postoperative dysmotility requires the use of temporary enteral nutrition until this improves. The resultant complete exocrine pancreatic insufficiency necessitates lifelong pancreatic enzyme replacement therapy and fat-soluble vitamin supplementation. A low-oxalate diet is recommended to prevent kidney stones. Carbohydrate counting is needed for the provision of short-term insulin dosing and possibly long-term as well, depending on the transplanted islet yield. Children should have careful nutrition assessment and monitoring at several follow-up visits during the first year, then annually, and at any time with concerns.

Current practices in islet cell autotransplantation

INTRODUCTION

Chronic pancreatitis and recurrent acute pancreatitis comprise a spectrum of disease that results in complications related to exocrine and endocrine insufficiency and chronic pain with narcotic dependence and poor quality of life. The mainstay of therapy has been medical and endoscopic therapy; surgery, especially total pancreatectomy, was historically reserved for few select patients as the obligate exocrine insufficiency and pancreatogenic diabetes (type 3C) are challenging to manage. The addition of islet cell autotransplantation after total pancreatectomy helps to mitigate brittle type 3c diabetes and prevents mortality related to severe hypoglycemic episodes and hypoglycemic unawareness. There have been more recent data demonstrating the safety of surgery and the beneficial long-term outcomes.

AREAS COVERED

The purpose of this review is to describe the current practices in the field of islet cell autotransplantation including the selection and evaluation of patients for surgery, their preoperative work up and management, surgical approach, post-operative management and outcomes.

EXPERT OPINION

Total pancreatectomy and islet cell autotransplantation has the ability to drastically improve quality of life and prevent brittle diabetes for patients suffering with chronic pancreatitis.

Unlocking the post-transplant microenvironment for successful islet function and survival

Islet transplantation (IT) offers the potential to restore euglycemia for patients with type 1 diabetes mellitus (T1DM). Despite improvements in islet isolation techniques and immunosuppressive regimes, outcomes remain suboptimal with UK five-year graft survivals (5YGS) of 55% and most patients still requiring exogenous insulin after multiple islet infusions. Native islets have a significant non-endocrine component with dense extra-cellular matrix (ECM), important for islet development, cell survival and function. Collagenase isolation necessarily disrupts this complex islet microenvironment, leaving islets devoid of a supporting framework and increasing vulnerability of transplanted islets. Following portal venous transplantation, a liver injury response is potentially induced, which typically results in inflammation and ECM deposition from liver specific myofibroblasts. The impact of this response may have important impact on islet survival and function. A fibroblast response and ECM deposition at the kidney capsule and eye chamber alongside other implantation sites have been shown to be beneficial for survival and function. Investigating the implantation site microenvironment and the interactions of transplanted islets with ECM proteins may reveal therapeutic interventions to improve IT and stem-cell derived beta-cell therapy.

Minimizing Post-Infusion Portal Vein Bleeding during Intrahepatic Islet Transplantation in Mice

Although the liver is currently accepted as the primary transplantation site for human islets in clinical settings, islets are transplanted under the kidney capsule in most rodent preclinical islet transplantation studies. This model is commonly used because murine intrahepatic islet transplantation is technically challenging, and a high percentage of mice could die from surgical complications, especially bleeding from the injection site post-transplantation. In this study, two procedures that can minimize the incidence of post-infusion portal vein bleeding are demonstrated. The first method applies an absorbable hemostatic gelatin sponge to the injection site, and the second method involves penetrating the islet injection needle through the fat tissue first and then into the portal vein by using the fat tissue as a physical barrier to stop bleeding. Both methods could effectively prevent bleeding-induced mouse death. The whole liver section showing islet distribution and evidence of islet thrombosis post-transplantation, a typical feature for intrahepatic islet transplantation, were presented. These improved protocols refine the intrahepatic islet transplantation procedures and may help laboratories set up the procedure to study islet survival and function in pre-clinical settings.

miR-125b promotes the NF-κB-mediated inflammatory response in NAFLD via directly targeting TNFAIP3

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has a high incidence and mortality rate, and a rapid course of clinical development. Although miR-125b is closely associated with the pathogenesis of liver fibrosis and hepatocellular carcinoma, the role of miR-125b in NAFLD remains unknown.

METHODS

The levels of TNF-α, IL-6, and IL-1β expression were examined via ELISA assays. Real-time PCR was used to determine the levels of miR-125b and tumor necrosis factor alpha-induced protein 3 (TNFAIP3) expression. The related molecular mechanisms were examined by performing luciferase reporter, western blot, and immunofluorescence assays. Structural changes in the livers of mice with NAFLD were observed via H&E staining.

RESULTS

The levels of TNF-α, IL-6, and IL-1β in NAFLD patients were greatly increased, and miR-125b expression was significantly up-regulated. The phosphorylation of IκBα and p65, and secretion of inflammatory factors were all markedly decreased by miR-125b silencing, but greatly increased by miR-125b overexpression. We also demonstrated that downregulation of TNFAIP3 in NAFLD was negatively correlated with miR-125b. Interestingly, the influence of miR-125b inhibitors on nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-mediated inflammatory responses were greatly aggravated by co-treatment with TNFAIP siRNA; however, the opposite results were obtained after treatment with miR-125b mimics and TNFAIP plasmids. Furthermore, the HF-induced liver damage and inflammatory responses were greatly ameliorated by miR-125b inhibitors but further aggravated by co-treatment with TNFAIP3 siRNA.

CONCLUSION

MiR-125b promoted the NF-κB-mediated inflammatory response in NAFLD by directly targeting TNFAIP3, and that mechanism might be target for treating NAFLD.

Portal flow dynamics after total pancreatectomy and autologous islet cell transplantation

BACKGROUND

Portal vein thrombosis (PVT) is a serious complication of total pancreatectomy and autologous islet cell transplant (TPAIT); therefore, portal flow dynamics are monitored by Doppler ultrasound postoperatively. The practical value of scheduled Doppler ultrasound examinations and the relationship between portal vein velocity, liver function, and complications have not been clearly studied.

METHODS

A retrospective review of 16 TPAIT was performed. Correlation analysis of portal vein velocity with indices of liver function, portal pressure, and volume of islet cells infused was conducted.

RESULTS

There was no correlation between portal vein velocity and postoperative liver function tests (LFTs). Larger volume of islet cells infused and higher intraoperative portal pressure correlated with decreased postoperative portal flow. There was no significant difference in portal pressure, portal vein velocity, or LFTs between those with normal and abnormal pre-infusion liver histopathology. While no PVT occurred, there were two cases of postoperative bleeding related to anticoagulation.

CONCLUSION

Segmental portal vein velocities are low in the setting of high tissue volume and portal pressure, but are not associated with variation in LFTs. Therefore, patient management in response to changes in velocities without clinical symptoms may be unnecessary.

Change in Functional Beta Cell Capacity With Time Following Autologous Islet Transplantation

OBJECTIVES

Autologous islet transplantation (AIT) is performed to preserve insulin secretory function in chronic pancreatitis patients undergoing total pancreatectomy (TP). No data exist on the effect of time lapse on beta cell function post TP-AIT. We aimed to investigate the factor of time lapse on beta cell function following TP-AIT.

METHODS

Retrospectively, we identified 31 adult patients with chronic pancreatitis who underwent TP-AIT between 2008 and 2016. Changes in beta cell function were assessed using (1) BETA-2 scores and (2) analysis of posttransplant mixed-meal tolerance testing.

RESULTS

Significant decrease in functional beta cell capacity expressed by BETA-2 scores was seen in the first 2 years following TP-AIT, with an annual decrease of 6.3 points in median BETA-2 score (interquartile range, 4.6-11.6; P = 0.002). In the mixed-meal tolerance testing analysis, nonsignificant trends toward higher glucose, lower insulin, and lower C-peptide were seen with time lapse. Additionally, higher hemoglobin A1c values (P = 0.033) and higher insulin requirements (P = 0.04) were seen with longer follow-up after AIT.

CONCLUSIONS

A steady drop in functional beta cell capacity was observed in the 2 years following TP and AIT. To our knowledge, to date this is the first report of the BETA-2 score applicability in the AIT setting.

Islet Transplantation in Children

PURPOSE OF REVIEW

Transplantation of the islets of Langerhans or the pancreas aims to restore blood sugar control. We review both forms of transplantation in children.

RECENT FINDINGS

Allogenic islet transplantation typically in to the liver via the portal vein may be a potential alternative to pancreas transplantation in the future. Autologous islet transplantation after total pancreatectomy is effective for debilitating symptoms of recurrent and chronic pancreatitis. Chronic pancreatitis in children is most often related to genetic mutations but is otherwise similar to adults with eventual exocrine and endocrine failure. Removal of the pancreas ameliorates pain, and islet transplantation preserves endocrine function to the extent allowed by the damage sustained by the pancreas from chronic inflammation. Despite the complexity of the operative procedure, the outcome of total pancreatectomy and autologous islet transplantation in children has been excellent including quality of life.

Use of anti-inflammatory agents in clinical islet cell transplants: A qualitative systematic analysis

Immunologic and non-immunologic loss of islet cells upon their transplantation into the liver leads to suboptimal outcomes. Anti-inflammatory agents are used during autologous and allogeneic transplantation. The aim of this qualitative systematic literature review is to evaluate their clinical use and safety. Electronic databases Embase, PubMed, Cumulative Index for Nursing and Allied Health Literature, ClinicalTrials.gov, and EU Clinical Trials Register were searched. Of the 216 unique citations, 10 with tumor necrosis factor (TNF) blockers [etanercept (ETA) or infliximab] and 3 with both TNF blockers and an interluekin-1 receptor antagonist [anakinra (ANA)]) were included. Of these, 12 were in allogeneic and one in autologous transplant. Insulin independence with decreased islet cells and number of transfusions were reported with their use. One infection was reported in a group receiving ETA. Analysis suggested that the use of ETA ± ANA have the potential to improve outcomes in islet cell transplant.

Autoimmunity in Autologous Islet Transplantation

Total pancreatectomy (TP) is increasingly being utilized for definitive treatment in patients with debilitating chronic pancreatitis (CP). In an effort to prevent surgical diabetes, the procedure can be performed in conjunction with transplantation of islets of Langerhans recovered from the patients’ own resected pancreas (autologous islet transplantation, AIT). Given that patients undergoing TP and AIT are traditionally assumed not to be at risk for the development of beta-cell autoimmunity, it is possible that the presence of autoimmune islet graft failure has been overlooked and underreported in this patient population. Herein, we describe two cases who underwent TP and AIT and later developed new-onset beta-cell autoimmunity (as evidenced by de novo glutamic acid decarboxylase antibody positivity), accompanied by complete insulin-dependent states. These cases emphasize the need for considering a possible autoimmune phenomenon in the workup of TP and AIT patients who manifest with unexpected and rapid deterioration in their glycemic control.