Long-term graft function after allogeneic islet transplantation

Islet transplants are emerging as a viable option for the treatment of type 1 diabetes mellitus. From 1989 to 1995 we conducted a series of simultaneous islet-kidney transplants in six uremic type 1 diabetic patients. We report two of these patients who have shown persistent islet graft function over many years. Two female patients with duration of diabetes of 27 and 37 years underwent simultaneous islet-kidney transplant under steroid- and cyclosporine-based immunosuppression. Freshly isolated islets were supplemented with cryopreserved islets from our low-temperature bank of frozen islets. A total islet mass of 9,866 and 15,061 islet equivalents/kg body weight, respectively, was transplanted into the liver through portal vein. Reasonable blood glucose control has been achieved for up to 6 years posttransplant in one patient, but there was minimum clinical benefit from the islet graft at 10 years. In contrast, sustained insulin secretion with nearly normal HbA1c at 13 years follow-up was observed in another patient, providing hope for improving long-term graft outcomes for islet transplant recipient.     

Influence of degree of hepatic steatosis on graft function and postoperative complications of liver transplantation

The aim of this study was to evaluate the impact on initial graft function of the degree of steatosis detected in the back-table biopsy, and its repercussion on the clinical results of the transplant (early posttransplant mortality and morbidity). We undertook a retrospective analysis of 300 liver transplants performed at our center from 1997 to 2004. A wedge liver biopsy was done routinely during back-table surgery (available in 294 transplants). The degree of steatosis was classified as: S0-no steatosis, 201 transplants; S1-mild steatosis (<30%), 58 transplants; S2-moderate steatosis (30% to 60%), 18 transplants; and S3-severe steatosis (>60%), 17 transplants. The ischemia-reperfusion (I/R) injury, based on the maximum mean peak aspartate transferase in the first 72 posttransplant hours, tended to be greater as the degree of graft steatosis increased: S0, 1316; S1, 1985; S2, 2446; and S3, 2955 (P < .005 between S0 and S3). This greater initial hepatic dysfunction was correlated in the group with severe steatosis with a higher rate of severe renal failure requiring hemofiltration/hemodialysis: S0, 9%; S1, 15%; S2, 11%; and S3, 41% (P < .001); as well as with a higher early mortality (90 days): S0, 10%; S1, 21%; S2, 11%; and S3, 41% (P < .001). The Kaplan-Meier survival curve showed a significant difference (log-rank and Breslow) between the group with severe steatosis and the group with no steatosis (P = .002). We conclude that the degree of liver graft steatosis is an important determinant of I/R injury, although this progressive increase in the I/R injury with the degree of steatosis only had clinical repercussions in the case of severe steatosis.     

Effect of graft steatosis on liver function and organ survival after liver transplantation

BACKGROUND: It was the aim to determine the effect of graft steatosis on intraoperative organ blood flow, postoperative liver function, and organ survival. METHODS: A total of 225 consecutive liver transplants were reviewed. Liver blood flow, hepatic function (AST, ALT, prothrombin time), and organ survival were determined. Donor liver grafts were categorized into 2 subgroups: mild (<30%) (n = 175) and moderate to severe (>/=30%) (n = 50) macrovesicular steatosis. RESULTS: Moderate to severe steatosis was associated with significantly increased AST and ALT levels and significantly diminished prothrombin time on the first and second postoperative day. By day 7 differences in liver function were no longer evident. Organ blood flow was not affected by steatosis. After adjustment for potential confounders, organ survival did not depend on the degree of donor steatosis (5-year-survival rates: 68% and 58% with steatosis <30%, or >/= 30%, respectively) (hazard ratio .754, confidence interval .458-1.242, P = .268). CONCLUSION: Steatotic livers can be transplanted safely with good results for long-term organ survival if other contraindications are absent.     

Hyperlipidemia after renal transplantation and its relation to graft and patient survival

INTRODUCTION: Hyperlipidemia is a multifactorial event that frequently develops following renal transplantation and may worsen the patient's prognosis. The aim of this study was to evaluate the incidence and concomitant factors for hyperlipidemia. METHODS: We studied 687 renal transplant recipients from 1988 to 2004 using a cross-sectional design to determine the frequency of hypercholestrolemia and hypertriglyceridemia before and 1 month to 1 year after renal transplantation, to evaluate its relation to patient and graft prognosis in two medical centers in Iran. Cyclosporine was the constant part of immunosuppressive treatment in all study subjects. RESULTS: One and 5-year graft survival times were 94.23% and 81.34%, respectively. The prevalence of hypercholestrolemia after transplantation was 59.9%. Mean (+/- 2 SE) serum cholesterol levels before and after transplantation were 161.15 +/- 3.81 and 213.83 +/- 4.53 mg/dL respectively (P=.000). Triglycerides levels, were 159.99 +/- 13.08 and 196.28 +/- 19.6 mg/dL respectively. There was no significant correlation between cyclosporine dose, graft and patient survivals, and severity of hyperlipidemia (determined by cholesterol and triglyceride levels). CONCLUSIONS: Lipid metabolism abnormalities observed in this study were similar to other reports. There was no correlation with patient or graft survival. In addition, there may routes for development of hyperlipidemia other than adverse complications of immunosuppressive drugs.     

Cross-sectional and prospective association between proinsulin secretion and graft function after clinical islet transplantation

Proinsulin levels as a marker of beta-cell dysfunction have not been described after clinical islet transplantation. Proinsulin secretion was studied in 23 type 1 diabetic patients after islet allotransplantation and in 20 age-matched nondiabetic controls. Fasting serum insulin, total proinsulin (TP), intact proinsulin, proinsulin fragments (PFs) and their ratios to insulin were determined 1 and 12 months after patients became insulin independent. TP, PF, and proinsulin/insulin ratios were lower in transplant recipients compared with controls, in patients who retained long-term insulin independence. Insulin, C-peptide, and intact proinsulin values were similar in transplant recipients and controls. Hormone levels remained stable over time in the group of patients who retained long-term insulin independence, but the TP and PF levels were higher at 12 months compared with 1 month in the group of patients who resumed insulin therapy. TP and PF levels were reduced in transplant recipients compared with controls but increased over time if insulin independence was lost.     

Hepatic steatosis and its relationship to transplantation

Fatty infiltration of the liver is common in the brain-dead donor population and has a strong correlation with primary nonfunction after cold preservation, a condition that is catastrophic to liver transplant recipients. This literature review examines factors associated with the development, diagnosis, quantification, and clinical management of this difficult condition. (Liver Transpl 2002;8:415-423.)     

生物发光显像技术用于移植胰岛的在体监测

目的 探讨生物发光显像技术用于移植胰岛监测的优势和可行性.方法 成年雄性C57BL/6小鼠腹腔注射链佐星,制成糖尿病模型.取C57BL/6小鼠和Bclb/c小鼠胰腺,消化、分离、纯化,获得胰岛,再将荧光素酶基因转入胰岛.将糖尿病模型小鼠分为同系移植组(n=20)和同种移植组(n=7),同系移植组糖尿病模型小鼠移植不同数量(分别为10、50、100和200个,每个数量移植5只小鼠)的C57BL/6小鼠胰岛,同种移植组糖尿病模型小鼠移植Bclb/c小鼠胰岛,胰岛均移植至左后腿上方皮下脂肪内.在设计时间点对受者进行生物发光扫描成像,观察光密度强弱及变化规律,并监测同种移植组受者的随机血糖变化.结果 移植后第6天,扫描成像可见移植区光密度随移植胰岛数量增多而增高,光密度与植入胰岛数量呈正相关.同种移植组受者的随机血糖在移植后2 d内迅速下降至正常水平,平均于11 d后再度逐渐升高至糖尿病水平,扫描成像显示移植区光密度在移植后6～7 d达到峰值,随后迅速下降;光密度开始下降时间为移植后(6.14±0.90)d,而血糖升高时间发生在移植后(10.00±0.82)d,前者改变时间明显早于后者(P＜0.05).结论 胰岛生物发光显像技术可及时、直观、准确的反映移植胰岛在机体内的存活状况,其成像改变早于血糖变化.     

Caspase inhibitor therapy enhances marginal mass islet graft survival and preserves long-term function in islet transplantation

Islet transplantation can provide insulin independence in patients with type 1 diabetes, but islets derived from two or more donors are often required. A significant fraction of the functional islet mass is lost to apoptosis in the immediate posttransplant period. The caspase inhibitor N-benzyloxycabonyl-Val-Ala-Asp-fluoromethyl ketone (zVAD-FMK) has been used therapeutically to prevent apoptosis in experimental animal models of ischemic injury, autoimmunity, and degenerative disease. In the current study, zVAD-FMK therapy was examined in a syngeneic islet transplant model to determine whether caspase inhibition could improve survival of transplanted islets. zVAD-FMK therapy significantly improved marginal islet mass function in renal subcapsular transplantation, where 90% of zVAD-FMK-treated mice became euglycemic with 250 islets, versus 27% of the control animals (P < 0.001). The benefit of zVAD-FMK therapy was further demonstrated after intraportal transplantation, where 75% of zVAD-FMK-treated animals established euglycemia with only 500 islets, and all of the controls remained severely diabetic (P < 0.001). zVAD-FMK pretreatment of isolated islets in the absence of systemic therapy resulted in no significant benefit compared with controls. Long-term follow-up of transplanted animals beyond 1 year posttransplant using glucose tolerance tests confirmed that a short course of zVAD-FMK therapy could prevent metabolic dysfunction of islet grafts over time. In addition, short-term zVAD-FMK treatment significantly reduced posttransplant apoptosis in islet grafts and resulted in preservation of graft insulin reserve over time. Our data suggest that caspase inhibitor therapy will reduce the islet mass required in clinical islet transplantation, perhaps to a level that would routinely allow for insulin independence after single-donor infusion.     

Influence of early graft function after renal transplantation and its impact on long-term graft and patient survival

Objective

To determine whether early graft function after transplantation impacted graft and patient survivals.

Materials and methods

Between 1981 and 2008, we performed 1308 renal transplantations. Poor early graft function was defined as a Cockroft-Gault glomerular filtration rate < 60 mL/min or less at 1 and 3 months posttransplant. Patients who lost their kidney or died within the first 12 months after transplantation were excluded from the study. Multivariate statistical analysis used Cox proportional hazards models.

Results

Of the 1308 patients 994 (78.8%) displayed poor early graft function at 1 month after transplantation (glomerular filtration rate < 60 mL/min), while 268 (21.2%) showed normal function (glomerular filtration rate ≥ 60 mL/min). The 2- and 6-year graft survival rates among the poor early graft function group were 96.8% and 85.8%, respectively, while those among the control group were 97.0% and 88.3%, respectively. The 2- and 6-year patient survival rates in the poor early graft function were 98.5% and 89.8% versus 98.9% and 96.3% in the control group. Similar results were observed at 3 months posttransplant. Controlling for patient age, donor age, HLA-AB and -DR mismatches, cold ischemia time, acute rejection episodes, cyclosporine therapy, and waiting time for transplantation, we did not observe early graft function to be a risk factor for graft survival or patient survival. Glomerular filtration rate at 2, 5, and 6 years after kidney transplantation was significantly lower in the poor early graft function than in the control group.

Conclusion

This study suggested that the quality of early graft function had no significant effect on graft and patient survival rate, but did have a significant influence on long-term renal function.     

Minimal focal steatosis of liver after islet transplantation in humans: a long-term study

Several reports have been published on islet transplantation in humans, but few data are available on the effect of islet infusion on the hepatic structure. Our aim was to evaluate in a longitudinal study the impact on the liver of intrahepatic islet transplantation. Clinical outcome and liver imaging were evaluated in 31 cases of islet-kidney transplantation (follow-up 38 +/- 4 months, range 12-96 months). Patients were divided into three groups: full function (FF, 9 cases: established insulin independence); partial function (PF, 16 cases: transient insulin independence, prolonged C-peptide secretion): no function (NF, 6 cases: exhaustion of C-peptide secretion within the first year). Upper abdomen sonogram was regularly performed during the whole follow-up period. Percutaneous liver biopsy was performed in case of echographic abnormalities. Multiple small areas of focal hyperechogenicity were observed in nine cases after 6-12 months. These findings were observed only in FF (two) and in PF (seven) patients. Fasting C-peptide levels at the time of echography were higher in negative than in positive patients (2.42 +/- 0.16 vs. 1.51 +/- 0.10 ng/ml, p = 0,0001). Liver biopsies showed focal macrovesicular steatosis, surrounded by normal liver parenchyma. Normal liver function was maintained. In conclusion, our results indicate that islet transplantation can lead to structural changes of the liver parenchyma (focal steatosis). It is more often observed in patients with partial function. Sonogram can be considered a specific method to reveal liver changes after islet transplantation.     

Prediction of delayed graft function after renal transplantation

Introduction:

Delayed graft function (DGF), defined as the need for dialysis during the first week after renal transplantation, is an important adverse clinical outcome. A previous model relied on 16 variables to quantify the risk of DGF, thereby undermining its clinical usefulness. We explored the possibility of developing a simpler, equally accurate and more user-friendly paradigm for renal transplant recipients from deceased donors.

Methods:

Logistic regression analyses addressed the occurrence of DGF in 532 renal transplant recipients from deceased donors. Predictors consisted of recipient age, gender, race, weight, number of HLA-A, HLA-B and HLA-DR mismatches, maximum and last titre of panel reactive antibodies, donor age and cold ischemia time. Accuracy was quantified with the area under the curve. Two hundred bootstrap resamples were used for internal validation.

Results:

Delayed graft function occurred in 103 patients (19.4%). Recipient weight (p < 0.001), panel of reactive antibodies (p < 0.001), donor age (p < 0.001), cold ischemia time (p = 0.005) and HLA-DR mismatches (p = 0.05) represented independent predictors. The multivariable nomogram relying on 6 predictors was 74.3% accurate in predicting the probability of DGF.

Conclusion:

Our simple and user-friendly model requires 6 variables and is at least equally accurate (74%) to the previous nomogram (71%). We demonstrate that DGF can be accurately predicted in different populations with this new model.     

Reduction of early graft loss after intraportal porcine islet transplantation in monkeys

BACKGROUND: Pig islets constitute a possible resolution to the shortage of human islets for transplantation. After intraportal infusion of porcine islets in primates, many islets are lost through what has been termed the instant blood-mediated inflammatory reaction (IBMIR). We report on our experience with IBMIR. METHODS: Ten monkeys underwent intraportal porcine islet transplantation. Immunosuppressive therapy was with conventional agents (n=3) or based on costimulation blockade (n=7). Treatment specific for IBMIR was administered in eight monkeys; two additional monkeys received no such therapy (group 1). Cobra venom factor completely inhibited complement activity in four (group 2) and dextran sulfate provided anticoagulation in four (group 3). Islet graft function was monitored by following blood glucose, insulin requirement, and porcine C-peptide values. RESULTS: In monkeys that received neither cobra venom factor nor dextran sulfate (group 1), there was rapid destruction of islets indicated by severe hypoglycemia and the need for dextrose infusion; C-peptide levels were initially low and further reduction occurred within the first five days. In both groups 2 and 3, there was significantly less destruction of islets and some reversal of diabetes. However, when 40,000 IEQ/kg were infused, normoglycemia was lost within five days, but when 80,000 IEQ/kg were infused in one case, normoglycemia was more persistent. We observed that even when C-peptide levels were in the normal range for healthy nondiabetic pigs, these were not sufficient to maintain normoglycemia in the monkeys. CONCLUSIONS: Although pretransplantation complement depletion or anticoagulation reduces porcine islet xenograft loss significantly, neither alone is sufficient to prevent IBMIR.     

High-dosed nicotinamide decreases early graft failure after pig to nude rat intraportal islet transplantation.

BACKGROUND: Clinical and experimental data indicate that early failure of intraportally grafted islets is mediated by inflammation. Although nicotinamide (NA) has the potential to protect rodent islets it is unknown whether large mammalian islets can be protected in an inflammatory environment. Therefore, we investigated NA-mediated protection of pig islets intraportally transplanted into diabetic nude rats characterized by involvement of NO in intrahepatic graft failure. METHODS: Nonfasting serum glucose levels were evaluated after intraportal transplantation (TX) of 4000 pig islets or intraportal sham-TX in diabetic nude rats infused for 7 days with saline (0 mg), 500 mg, or 1000 mg NA/kg/day. The nitrate/nitrite serum levels were colorimetrically quantified 0, 24, and 48 hr posttransplant. RESULTS: Graft survival after 21 days was not improved (2/13) by 500 mg NA compared to 0 mg NA (1/22) and 500 mg sham-TX (0/7). A total of 1000 mg NA promoted sustained normoglycemia in transplanted rats (10/18, P<0.001 vs. 0 mg NA, P<0.05 vs. 500 mg NA) but deteriorated hyperglycemia in 1000 mg NA sham-TX (P<0.01 vs. 0 mg sham-TX). Regeneration of endogenous islets determined as pancreatic insulin content was only measured in islet recipients receiving 1000 mg NA (P<0.001). Posttransplant NO levels were not affected by NA and increased in all recipients two-fold (P<0.05 vs. day 0). CONCLUSIONS: Compared with efficient administration in syngeneic rodent models NA has to be applied in significant higher doses for protection of xenografted pig islets implying that protection of islets from large mammalians after transplantation into a proinflammatory organ seems feasible. In contrast to other observations graft survival was not mediated by interference of NA with hepatic NO generation.     

Quantitative in vivo islet potency assay in normoglycemic nude mice correlates with primary graft function after clinical transplantation

Reliable assays are critically needed to monitor graft potency in islet transplantation (IT). We tested a quantitative in vivo islet potency assay (QIVIPA) based on human C-peptide (hCP) measurements in normoglycemic nude mice after IT under the kidney capsule. QIVIPA was initially tested by transplanting incremental doses of human islets. hCP levels in mice were correlated with the number of transplanted islet equivalents (r(2) = 0.6, P<0.01). We subsequently evaluated QIVIPA in eight islet preparations transplanted in type 1 diabetic patients. Conversely to standard criteria including islet mass, viability, purity, adenosine triphosphate content, or glucose stimulated insulin secretion, hCP in mice receiving 1% of the final islet product was correlated to primary graft function (hCP increase) after IT (r(2)=0.85, P<0.01). QIVIPA appears as a reliable test to monitor islet graft potency, applicable to validate new methods to produce primary islets or other human insulin secreting cells.