Marie Felldin

Islet Surface Heparinization Prevents the Instant Blood-Mediated Inflammatory Reaction in Islet Transplantation

OBJECTIVE—In clinical islet transplantation, the instant blood-mediated inflammatory reaction (IBMIR) is a major factor contributing to the poor initial engraftment of the islets. This reaction is triggered by tissue factor and monocyte chemoattractant protein (MCP)-1, expressed by the transplanted pancreatic islets when the islets come in contact with blood in the portal vein. All currently identified systemic inhibitors of the IBMIR are associated with a significantly increased risk of bleeding or other side effects. To avoid systemic treatment, the aim of the present study was to render the islet graft blood biocompatible by applying a continuous heparin coating to the islet surface. RESEARCH DESIGN AND METHODS—A biotin/avidin technique was used to conjugate preformed heparin complexes to the surface of pancreatic islets. This endothelial-like coating was achieved by conjugating barely 40 IU heparin per full-size clinical islet transplant. RESULTS—Both in an in vitro loop model and in an allogeneic porcine model of clinical islet transplantation, this heparin coating provided protection against the IBMIR. Culturing heparinized islets for 24 h did not affect insulin release after glucose challenge, and heparin-coated islets cured diabetic mice in a manner similar to untreated islets. CONCLUSIONS—This novel pretreatment procedure prevents intraportal thrombosis and efficiently inhibits the IBMIR without increasing the bleeding risk and, unlike other pretreatment procedures (e.g., gene therapy), without inducing acute or chronic toxicity in the islets.

Optimising islet engraftment is critical for successful clinical islet transplantation

Clinical islet transplantation is currently being explored as a treatment for persons with type 1 diabetes and hypoglycaemia unawareness. Although ‘proof-of-principle’ has been established in recent clinical studies, the procedure suffers from low efficacy. At the time of transplantation, the isolated islets are allowed to embolise the liver after injection in the portal vein, a procedure that is unique in the area of transplantation. A novel view on the engraftment of intraportally transplanted islets is presented that could explain the low efficacy of the procedure.

Nicotinamide inhibits tissue factor expression in isolated human pancreatic islets: Implications for clinical islet transplantation

Background. Islet-produced tissue factor (TF) triggers an adverse clotting reaction, the instant blood-mediated inflammatory reaction (IBMIR), providing a likely explanation for the need of tissue from multiple donors in clinical islet transplantation. In this study, the authors investigated whether compounds previously shown to affect TF and macrophage chemoattractant protein (MCP)-1 expression in monocytes and endothelial cells have the same effect in human islet cells. Methods. Islets were cultured in the presence of l-arginine, cyclosporine A, enalapril, or nicotinamide for 48 hr, after which the TF content and MCP-1 expression were assessed. The effect of nicotinamide on IBMIR was evaluated by exposing the treated islets to fresh human ABO-compatible blood in an in vitro loop model. Results. Nicotinamide was the only compound that significantly reduced both TF and MCP-1. This reduction was dose-dependent. The level of MCP-1 was strongly correlated with TF expression (r2=0.98). In addition, the level of TF was also correlated with the ability of the islets to initiate IBMIR (r2=0.94). Conclusions. TF and MCP-1 expression in human islets can be decreased by adding nicotinamide to the culture medium. These observations indicate that the adverse effects of IBMIR in clinical islet transplantation could be reduced without endangering the recipient using antithrombotic drugs.

No beneficial effect of two-layer storage compared with UW-storage on human islet isolation and transplantation

Background. Shipment of pancreata between distant centers is frequently associated with prolonged cold ischemia time (CIT) that leads to poorer outcomes for islet transplantation. Clinical pilot trials have indicated that oxygenation of explanted human pancreata utilizing the two-layer method (TLM) allows the use of marginal donor pancreata for islet transplantation. The present study aimed to clarify whether TLM enhances the ischemic tolerance of human pancreata. Methods. We analyzed retrospectively the outcome of 200 human islet isolations performed after TLM preservation or storage in University of Wisconsin solution (UWS). Results. Donor characteristics and digestion parameters did not vary significantly between TLM-preserved and UWS-stored pancreata. No differences were observed between experimental groups with regard to islet yield, purity, or dynamic glucose stimulation index after either short or prolonged CIT. However, CIT and stimulation index were negatively correlated in each experimental group. The isolation outcome in donors aged ≥60 years was not increased after TLM preservation when compared to UWS storage. No effect was observed regarding islet posttransplant function in recipients with established kidney grafts. Conclusions. The present study suggests that the ischemic tolerance of human pancreata cannot be extended by TLM preservation. In addition, TLM does not seem to improve the isolation outcome for pancreata from elderly donors.

Rescue therapy with tacrolimus (FK 506) in renal transplant recipients--a Scandinavian multicenter analysis.

Abstract All renal allograft recipients (n= 32) in Sweden and Norway who were converted from cy‐closporin(CyA)‐based immunosuppression to FK 506 (tacrolimus) between October 1992 and June 1995 were analyzed retrospectively. The reasons for conversion were acute refractory rejection (n= 21), chronic rejection (n= 4), and suspected CyA toxicity (n= 6); one patient was converted for psychological reasons. The mean time from transplantation to conversion was 29 (range 1–243) weeks and there was a mean follow‐up of 46 (2–143) weeks. Overall graft survival was 59 %, with graft survival 52 % in patients converted because of acute rejection, 50 % in patients converted because of chronic rejection, and 83 % in patients converted because of CyA toxicity. There was no significant correlation between preconversion serum creatinine and outcome. Seventy‐two percent of the patients had significant side effects during FK 506 treatment, the most frequent ones being neurological and gastrointestinal symptoms. These improved after dose reduction. Two patients became overimmunosup‐pressed and developed lymphoma. One patient died of the primary kidney disease, hemolytic uraemic syndrome. We conclude that FK 506 therapy is able to salvage kidneys with acute refractory rejection and that it is an alternative in patients with CyA toxicity. However, the risk of overimmunosuppression must be considered.

Early renal function post-liver transplantation is predictive of progressive chronic kidney disease

Objective. With improvements in long-term results after liver transplantation, chronic kidney disease (CKD) has become a highly relevant problem. The early measurement of the glomerular filtration rate (GFR) can identify those patients who are at risk of developing CKD years after liver transplantation. The aims of this study were to describe the prevalence of CKD 5 years after liver transplantation, to study the correlation between measured GFR early after transplantation and late renal function and to identify patients at risk of developing late CKD after liver transplantation. Material and methods. A total of 152 patients who were at least 5 years post-liver transplantation were studied. Measured GFR with Chromium EDTA or iohexol clearance was followed-up for 5 years (n=152) and 10 years (n=41). Results. The overall decrease in measured GFR was 36% after 5 years and 42% after 10 years. Eight patients (5%) required renal replacement therapy. GFR levels pretransplantation showed a poor correlation with later renal function (at 5 years). The GFR measured at 3 months and 1 year post-transplantation correlated well with measured GFR at 5 years post-transplantation. Multivariate analysis showed that measured GFR of less than 30 ml at 3 months post-transplantation was significantly associated with CKD at 5 years post-transplantation. Conclusions. GFR levels below 30 ml/min/1.73 m2 at 3 months post-liver transplantation are associated with the development of later CKD Stage 4–5 long after liver transplantation. The importance of this finding is the possibility of identifying at an early stage those individuals that may benefit from early implementation of calcineurin sparing or a withdrawal regimen with the goal of preserving long-term renal function.

Conversion From Calcineurin Inhibitor to Either Mycophenolate Mofetil or Sirolimus Improves Renal Function in Liver Transplant Recipients With Chronic Kidney Disease : Results of a Prospective Randomized Trial

BACKGROUND Chronic kidney disease (CKD) has emerged as a significant cause of morbidity and a risk factor for mortality after orthotopic liver transplantation (OLT). The use of calcineurin inhibitor (CNI)-based immunosuppression is an important etiologic factor for developing CKD. CNI discontinuation or minimization protocols with replacement of the CNI with non-nephrotoxic drugs, such as mycophenolate mofetil (MMF) or sirolimus (SRL), may have the potential to preserve or recover renal function. PATIENTS AND METHODS In this prospective, randomized, single-center study with CNI discontinuation, OLT recipients with CKD (measured glomerular filtration rate [GFRm] 15-45 mL/min/1.73 m(2)) were randomized to either SRL or MMF-based immunosuppression. The main objective was to study the effect of CNI discontinuation on renal function. Secondary aims were to assess the frequency of biopsy-proven acute rejection episodes (BPAR) and adverse events (AE). Renal function was followed with GFRm using 51-Chromium EDTA clearance at baseline, 3 months, and 1 year. Patients were stratified according to baseline GFRm > versus <30 mL/min/1.73 m(2). The 25 patients were enrolled for MMF (n = 13) or SRL (n = 12). The median age at inclusion was 59 years (range, 25-66) and the median number of years after OLT was 4.4 (range, 1-13). Twenty-two patients were followed up for a year; MMF (n = 12) and SRL (n = 10). RESULTS Mean GFRm for the whole cohort (n = 25) was 31+/-8 mL/min/1.73 m(2) at baseline. After 3 months the GFRm (n = 23) increased to 40+/-10 mL/min/1.73 m(2) (P = .0001) and at 1 year 42 +/- 11 mL/min/1.73 m(2) (n = 22). There was not significant difference between the MMF and the SRL study arms. The cohort (n = 8) with baseline GFRm <30 mL showed a 63% (P = .003) increased filtration after 1 year. There was no significant difference in the frequency or severity of AE between the study arms with the exception of oral ulcerations and persistent hypertriglyceridemia in the SRL group. Two deaths occurred, 1 in each study arm, both probably unrelated to the change in immunosuppression. There were no BPAR episodes. CONCLUSION CNI discontinuation and replacement with either MMF or SRL resulted in a significant improvement in renal function even in those patients with severe CKD. The protocol was effective with no acute rejection episodes. The SRL arm showed a higher frequency of oral apthous ulcerations and hypertriglyceridemia. Future studies addressing long-term renal function after CNI discontinuation are needed.

Treatment with the molecular adsorbent recirculating system in patients with acute liver failure.

MOLECULAR adsorbent recirculating system (MARS) is a new treatment for liver failure based on the same principle as hemodialysis. However, the blood is dialyzed against an albumin-enriched dialyzate to facilitate the removal of albumin-bound toxins as well as bilirubin, aromatic amino acids and water-soluble substances. This method, which has been introduced clinically in recent years, is best used in patients with acute decompensation of chronic liver disease, but there are also some reports in patients with acute liver failure (ALF). We decided to use MARS in patients with ALF who also were considered to need a liver transplant.

The antibody response to pandemic H1N1 2009 influenza vaccine in adult organ transplant patients

Limited data are available regarding antibody response and the safety of the monovalent influenza A H1N1/09 vaccine for immunocompromised patients. In this study, the humoral response to this vaccine in solid organ transplant (SOT) recipients and healthy individuals was evaluated. Eighty‐two SOT recipients and 28 healthy individuals received two doses of the influenza A H1N1/09 AS03 adjuvanted vaccine containing 3.75 mg of haemagglutinin at a 3‐ to 4‐week interval. Serum samples were drawn at baseline and 3–4 weeks after the first and second vaccine doses. Seroprotective titres were measured with a haemagglutination inhibition. After the first dose seroprotective titres were observed in 69% of the SOT patients and in 96% of the healthy controls (P = 0.006), and increased after the second dose to 80% and 100%, respectively (P = 0.003). All controls and 77% of the SOT recipients achieved a ≥4‐fold titre rise after the first immunisation (P = 0.005). The vaccine was well tolerated and no acute rejection was observed. Influenza A H1N1/09 vaccine elicited a protective antibody response in the majority of SOT recipients, but the response was lower when compared with controls. A second dose significantly improved vaccine immunogenicity in SOT recipients. (ClinicalTrials.gov number: NCT01254955)

Transplanted Functional Islet Mass: Donor, Islet Preparation, and Recipient Factors Influence Early Graft Function in Islet-After-Kidney Patients

Background. The ability to predict clinical function of a specific islet batch released for clinical transplantation using standardized variables remains an elusive goal. Methods. Analysis of 10 donor, 7 islet isolation, 3 quality control, and 6 recipient variables was undertaken in 110 islet-after-kidney transplants and correlated to the pre- to 28-day posttransplant change in C-peptide to glucose and creatinine ratio (&Dgr;CP/GCr). Results. Univariate analysis yielded islet volume transplanted (Spearman r=0.360, P<0.001) and increment of insulin secretion (r=0.377, P<0.001) as variables positively associated to &Dgr;CP/GCr. A negative association to &Dgr;CP/GCr was cold ischemia time (r=−0.330, P<0.001). A linear, backward-selection multiple regression was used to obtain a model for the transplanted functional islet mass (TFIM). The TFIM model, composed of islet volume transplanted, increment of insulin secretion, cold ischemia time, and exocrine tissue volume transplanted, accounted for 43% of the variance of the clinical outcome in the islet-after-kidney data set. Conclusion. The TFIM provides a straightforward and potent tool to guide the decision to use a specific islet preparation for clinical transplantation.