Babak Movahedi

Correlation between beta cell mass and glycemic control in type 1 diabetic recipients of islet cell graft.

Islet grafts can induce insulin independence in type 1 diabetic patients, but their function is variable with only 10% insulin indepence after 5 years. We investigated whether cultured grafts with defined β cell number help standardize metabolic outcome. Nonuremic C-peptide-negative patients received an intraportal graft with 0.5–5.0 × 106 β cells per kilogram of body weight (kgBW) under antithymocyte globulin and mycophenolate mofetil plus tacrolimus. Metabolic outcome at posttransplant (PT) month 2 was used to decide on a second graft under maintenance mycophenolate mofetil/tacrolimus. Graft function was defined by C-peptide >0.5 ng/ml and reduced insulin needs, metabolic control by reductions in HbA1c, glycemia coefficient of variation, and hypoglycemia. At PT month 2, graft function was present in 16 of 17 recipients of >2 × 106 β cells per kgBW versus 0 of 5 with lower number. The nine patients with C-peptide >1 ng/ml and glycemia coefficient of variation of <25% did not receive a second graft; five of them were insulin-independent until PT month 12. The 12 others received a second implant; it achieved insulin-independence at PT month 12 when the first and second graft contained >2 × 106 β cells per kgBW. Of the 20 recipients of at least one graft with >2 × 106 β cells per kgBW, 17 maintained graft function and metabolic control up to PT month 12. At PT month 12, β cell function in insulin-independent patients ranged around 25% of age-matched control values. Thus, 1-year metabolic control can be reproducibly achieved and standardized by cultured islet cell grafts with defined β cell number.

Differences in Baseline Lymphocyte Counts and Autoreactivity Are Associated With Differences in Outcome of Islet Cell Transplantation in Type 1 Diabetic Patients

OBJECTIVE The metabolic outcome of islet cell transplants in type 1 diabetic patients is variable. This retrospective analysis examines whether differences in recipient characteristics at the time of transplantation are correlated with inadequate graft function. RESEARCH DESIGN AND METHODS Thirty nonuremic C-peptide–negative type 1 diabetic patients had received an intraportal islet cell graft of comparable size under an ATG-tacrolimus–mycophenolate mofetil regimen. Baseline patient characteristics were compared with outcome parameters during the first 6 posttransplant months (i.e., plasma C-peptide, glycemic variability, and gain of insulin independence). Correlations in univariate analysis were further examined in a multivariate model. RESULTS Patients that did not become insulin independent exhibited significantly higher counts of B-cells as well as a T-cell autoreactivity against insulinoma-associated protein 2 (IA2) and/or GAD. In one of them, a liver biopsy during posttransplant year 2 showed B-cell accumulations near insulin-positive β-cell aggregates. Higher baseline total lymphocytes and T-cell autoreactivity were also correlated with lower plasma C-peptide levels and higher glycemic variability. CONCLUSIONS Higher total and B-cell counts and presence of T-cell autoreactivity at baseline are independently associated with lower graft function in type 1 diabetic patients receiving intraportal islet cells under ATG-tacrolimus–mycophenolate mofetil therapy. Prospective studies are needed to assess whether control of these characteristics can help increase the function of islet cell grafts during the first year posttransplantation.

Pancreatic duct cells in human islet cell preparations are a source of angiogenic cytokines interleukin-8 and vascular endothelial growth factor

OBJECTIVE—Engraftment and function of human islet cell implants is considered to be dependent on their rapid and adequate revascularization. Studies with rodent islet grafts have shown that vascular endothelial growth factor (VEGF) expression by β-cells can promote this process. The present work examines whether human islet preparations produce VEGF as well as interleukin (IL)-8, another angiogenic protein, and assesses the role of contaminating duct cells in VEGF and IL-8–mediated angiogenesis. RESEARCH DESIGN AND METHODS—Human islet and pancreatic duct cell preparations are compared for their respective expression and production of VEGF and IL-8 during culture as well as following transplantation in nonobese diabetic (NOD)/scid mice. The associated angiogenic effects are measured in an in vitro aortic ring assay and in an in vivo chick embryo chorioallantoic membrane assay. RESULTS—Cultured pancreatic duct cells expressed 3- and 10-fold more VEGF and IL-8, respectively, than cultured human islet endocrine cells and released both proteins at angiogenic levels. The angiogenic effect of purified duct cells was higher than that of purified endocrine islet cells and was completely blocked by a combination of IL-8 and VEGF antibodies. Human duct cell implants under the kidney capsule of NOD/scid mice expressed higher levels of IL-8 and VEGF than human islet cell implants and induced circulating IL-8 and VEGF levels during the first day posttransplantation. CONCLUSIONS—Human duct cell–released IL-8 and VEGF may help revascularization of currently used human islet cell grafts. Further work should examine whether and when this effect can prevail over other inflammatory and immune influences of this cell type.

Alpha 1-antitrypsin reduces inflammation and enhances mouse pancreatic islet transplant survival

The promise of islet cell transplantation cannot be fully realized in the absence of improvements in engraftment of resilient islets. The marginal mass of islets surviving the serial peritransplant insults may lead to exhaustion and thereby contribute to an unacceptably high rate of intermediate and long-term graft loss. Hence, we have studied the effects of treatment with alpha 1-antitrypsin (AAT) in a syngeneic nonautoimmune islet graft model. A marginal number of syngeneic mouse islets were transplanted into nonautoimmune diabetic hosts and islet function was analyzed in control and AAT treated hosts. In untreated controls, marginal mass islet transplants did not restore euglycemia. Outcomes were dramatically improved by short-term AAT treatment. Transcriptional profiling identified 1,184 differentially expressed transcripts in AAT-treated hosts at 3 d posttransplantation. Systems-biology–based analysis revealed AAT down-regulated regulatory hubs formed by inflammation-related molecules (e.g., TNF-α, NF-κB). The conclusions yielded by the systems-biology analysis were rigorously confirmed by QRT-PCR and immunohistology. These data suggest that short-term AAT treatment of human islet transplant recipients may be worthy of a clinical trial.

CD40 expression on human pancreatic duct cells: role in nuclear factor-kappa B activation and production of pro-inflammatory cytokines.

Aims/hypothesisHuman pancreatic duct cells are closely associated with islet beta cells, and contaminate islet suspensions transplanted in Type 1 diabetes mellitus patients. Activated duct cells produce cytotoxic mediators and possibly contribute to the pathogenesis of Type 1 diabetes mellitus or islet graft rejection. As CD40 transduces activation signals involved in inflammatory and immune disorders, we investigated CD40 expression on duct cells and their response to CD40 engagement.MethodsCD40 expression on human pancreatic duct cells was analysed by flow cytometry and immunohistochemical analyses. To assess the function of CD40 expression on duct cells, activation of the transcription factor nuclear factor-kappa B was determined using electrophoretic mobility shift assay and ELISA. Cytokine mRNA levels were quantified by real-time RT-PCR, and protein levels by Luminex technology.ResultsIsolated human pancreatic duct cells and Capan-2 cell lines were found to express constitutively CD40. The expression of CD40 on duct cells was confirmed in vivo on human normal and pathological pancreatic specimens. CD40 ligation on Capan-2 cells induced rapid nuclear factor-kappa B activation, and supershift assays demonstrated that p50/p65 heterodimers and p50/p50 homodimers were present in the activated complexes in the nucleus. This activation was accompanied by tumour necrosis factor-α and interleukin-1β mRNA accumulation. Tumour necrosis factor-α protein secretion was confirmed in CD40-activated Capan-2 cells and in isolated human pancreatic duct cells.Conclusions/interpretationInteraction between activated T lymphocytes expressing CD40 ligand and duct cells expressing CD40 may contribute to the immune responses involved in Type 1 diabetes mellitus and islet graft rejection. Interfering with CD40-mediated duct cell activation could alleviate beta cell damage of immune origin.

Functional status predicts postoperative mortality after liver transplantation

Frail patients are more vulnerable to perioperative stressors of liver transplantation (LT). Program Specific Reports, used in transplant center auditing, risk‐adjust for frailty using the Karnofsky Performance Status (KPS) scale. We evaluate the extent to which functional impairment/disability is associated with increased risk of postoperative death.

Prevention of Nonimmunologic Loss of Transplanted Islets in Monkeys

The nonimmunologic loss of islets in the pre‐, peri‐, and early post‐islet transplant periods is profound. To determine the potential role that transplantation of only a marginal mass of functioning beta cells may play in triggering late nonimmunologic graft loss, we studied the effect of treatment with alpha‐1‐antitrypsin (AAT) in the autologous cynomolgus islet transplant model. A marginal mass of autologous islets, that is islets prepared from 70% to 80% of the pancreas, was transplanted at 1600–4100 IEQ/kg into subtotal pancreatectomized, streptozotocin‐treated and insulin‐deficient diabetic hosts. In this marginal mass islet transplant model, islet function is insidiously lost over time and diabetes recurs in all untreated monkeys by 180 days posttransplantation. Short‐term treatment with AAT, an acute phase reactant, in the peri‐transplant period serves to terminate inflammation through effects upon expression of TGFβ, NFκB and AKT and favorably altering expression of cell death and survival pathways, as detected by a system biology approach and histology. These effects enabled functional expansion of the islet mass in transplanted hosts such that graft function improves rather than deteriorating over time.

Liver Transplantation for Unresectable Colorectal Cancer Liver Metastases: A Paradigm Change?

To the Editor: H istorically, colorectal cancer liver metastases have been considered a terminal disease. In the last 20 years, despite dramatic improvements in treatment, especially neoadjuvant therapy and liver resection, the prognosis for patients with nonresectable colorectal carcinoma (NRCRC) liver metastases remains dismal. Colorectal cancer metastases are considered an absolute contraindication for liver transplant because historically results were very poor.1 Hagness et al2 challenged the status quo by revisiting the idea of liver transplantation for NRCRC liver metastases. The estimated overall 5-year survival rate after transplant in their study was 60% compared with only 18% in previous reports.3 This is a major achievement, considering that chemotherapy alone typically results in a 5-year survival rate of only 5% to 10%.4 Important ethical considerations must be addressed before the approach of Hagness et al can be applied in other parts of the world, due to the significant shortage of liver grafts. The survival benefit of liver transplantation for NRCRC liver metastasis should approximate the outcomes expected of conventional indications for liver transplantation. The scarcity of liver organs is the reason for limiting the allocation to patients with the greatest likelihood of survival. With this, liver transplantation for cancer has been restricted to selected tumors within defined stages to achieve outcomes similar to transplants for nonneoplastic end-stage liver disease.5 Hepatocellular carcinoma (HCC), as an indication for transplant, became acceptable only after multiple refinements in selection criteria rendered posttransplant survival comparable with non-HCC indications. Today, HCC comprises 35% of all transplant cases in the United States.5 Cholangiocarcinoma was once an absolute contraindication for transplantation; however, currently, neoadjuvant therapy followed by transplantation in selected patients can achieve 65% recurrent-free 5-year survival rate.6 Taking into consideration the limitations of a small study, Hagness

Single-Center Experience With Liver Transplant Using Donors With Very High Transaminase Levels

OBJECTIVES Elevation of transaminases has been used as a marker of hepatic ischemic injury and as a crucial parameter for liver graft assessment. However, analysis of serum transaminases has limitations regarding the quantitative assessment of liver necrosis and is not a reliable predictor of outcomes. MATERIALS AND METHODS We retrospectively reviewed the medical records of all liver transplants (N = 238) performed at the UMass Memorial Medical Center from 2009 to 2013. RESULTS Fourteen liver grafts showed high peak aminotransferases alanine aminotransferase (ALT) and aspartate aminotransferase (AST) at > 1000 U/L. This high aminotransferase group was compared with 224 donors with low transaminase levels (ALT/AST < 1000 U/L). The high transaminase donors had a median peak AST level of 3216 U/L (range, 1823-13?030 U/L) and ALT level of 2677 U/L (range, 812-7080 U/L). The high transaminase donors showed higher levels of lactate dehydrogenase, international normalized ratio, total bilirubin, and gamma-glutamyltransferase compared with low transaminase donors; however, only lactate dehydrogenase results reached statistical significance. None of the grafts from the high transaminase donors showed primary nonfunction. Three-year graft and patient survival rates were similar in both groups (75% vs 80% [P = .48] and 72% vs 82% [P = .33], respectively). In an analysis of the discard rate of livers over a 10-year period in the United States using the Scientific Registry of Transplant Recipients database, the discard rate of livers with high aminotransferase levels was 69.14% compared with 22.23% for livers with low transaminase levels. CONCLUSIONS Liver grafts from donors with high transaminase levels can lead to clinical results that are similar to liver grafts from donors who had lower peak transaminase levels.

Successful Renal Transplantation after Presumed Cyanide Toxicity Treated with Hydroxocobalamin and Review of the Literature

We report two cases of successful renal transplantation with allografts from donors who suffered anoxic brain injury as the primary cause of death from house fires. Each was treated prophylactically with hydroxocobalamin (Cyanokit) for suspected cyanide toxicity. During organ procurement, gross examination was notable for deep discoloration of the parenchymal tissues. Approximately 6 and 18 months after transplantation, both recipients have excellent renal graft function and remain independent from hemodialysis (HD). Hydroxocobalamin is the antidote for suspected acute cyanide toxicity. While largely tolerated by the recipient, there is concern over the potential functional implications of the associated side effects of dramatic tissue discoloration and development of oxalate crystals. Furthermore, difficulties performing hemodialysis in patients treated with hydroxocobalamin have been reported due to discoloration of the effluent fluid impacting the colorimetric sensor, causing false alarms and repetitive interruptions. As such, many transplant centers in the United States (US) continue to reject these organs. We seek to highlight two cases of successful transplantation following donor administration of hydroxocobalamin (Cyanokit) and present the first documented case of successful perioperative intermittent hemodialysis following transplantation of an allograft exposed to hydroxocobalamin. Furthermore, we emphasize the importance of optimal organ utilization and caution against unnecessary refusal.