Alpha-1-antitrypsin in cell and organ transplantation.

Limited availability of donor organs and risk of ischemia-reperfusion injury (IRI) seriously restrict organ transplantation. Therapeutics that can prevent or reduce IRI could potentially increase the number of transplants by increasing use of borderline organs and decreasing discards. Alpha-1 antitrypsin (AAT) is an acute phase reactant and serine protease inhibitor that limits inflammatory tissue damage. Purified plasma-derived AAT has been well tolerated in more than 30 years of use to prevent emphysema in AAT-deficient individuals. Accumulating evidence suggests that AAT has additional anti-inflammatory and tissue-protective effects including improving mitochondrial membrane stability, inhibiting apoptosis, inhibiting nuclear factor kappa B activation, modulating pro- vs anti-inflammatory cytokine balance, and promoting immunologic tolerance. Cell culture and animal studies have shown that AAT limits tissue injury and promotes cell and tissue survival. AAT can promote tolerance in animal models by downregulating early inflammation and favoring induction and stabilization of regulatory T cells. The diverse intracellular and immune-modulatory effects of AAT and its well-established tolerability in patients suggest that it might be useful in transplantation. Clinical trials, planned and/or in progress, should help determine whether the promise of the animal and cellular studies will be fulfilled by improving outcomes in human organ transplantation.

Nanofiltered C1-esterase inhibitor for the acute management and prevention of hereditary angioedema attacks due to C1-inhibitor deficiency in children.

OBJECTIVES: To evaluate the use of Cinryze (nanofiltered C1-esterase inhibitor [C1 INH-nf]) for the acute management and prevention of hereditary angioedema attacks in the subgroup of children and adolescents who participated in 2 placebo-controlled and 2 open-label extension studies. STUDY DESIGN: In the acute-attack treatment studies, the efficacy of 1000 U of C1 INH-nf (with an additional 1000 U given 1 hour later if needed) was assessed based on the time to the start of symptomatic relief and the proportion of patients experiencing relief within 4 hours of therapy. In the prophylaxis studies, C1 INH-nf 1000 U was given twice weekly, and efficacy was based on the frequency of attacks. RESULTS: Across 4 studies, 46 children received a total of 2237 C1 INH-nf infusions. The median time to the start of unequivocal relief in the acute-attack treatment study (n = 12) was 30 minutes with C1 INH-nf, compared with 2 hours for placebo. In the open-label extension (n = 22), clinical relief began within 4 hours of therapy in 89% of attacks. In the prophylaxis study (n = 4), the number of attacks was reduced by approximately 2-fold with C1 INH-nf compared with placebo. In the prophylaxis open-label extension (n = 23), the median monthly attack rate decreased from 3.0 before treatment to 0.39 with C1 INH-nf use. CONCLUSION: In children, C1 INH-nf was well tolerated, provided relief from symptoms of hereditary angioedema attacks, and reduced the rate of attacks.

Nanofiltered C1 esterase inhibitor (human) for hereditary angioedema attacks in pregnant women.

Data are limited on hereditary angioedema (HAE) in pregnant women and the safety and efficacy of therapies for treatment and prevention of HAE attacks during pregnancy. Prospective studies are unlikely given the rarity of HAE and ethical considerations regarding enrollment of pregnant female subjects in clinical trials. A retrospective analysis of clinical trial and compassionate-use data was conducted to identify subjects who received nanofiltered C1 esterase inhibitor (C1 INH-nf; human) during pregnancy. This study evaluates the efficacy and safety of human C1 INH-nf for treatment and prevention of HAE attacks in pregnant women. Data from pregnant subjects enrolled in either open-label extensions of two randomized, double-blind, placebo-controlled trials of C1 INH-nf or in a compassionate-use program were retrospectively analyzed for efficacy (e.g., total attacks, attack frequency during prophylaxis, and monthly attack rates) and safety (e.g., pregnancy outcomes and adverse events). C1 INH-nf was administered as acute treatment, preprocedural prophylaxis, or routine prophylaxis. C1 INH-nf prophylaxis substantially reduced monthly attack rates. Of 16 subjects, 13 delivered 14 healthy neonates (1 set of twins). Two adverse fetal outcomes were reported; neither was considered by the principal investigator to be related to C1 INH-nf. One subject's pregnancy outcome was unknown. This analysis shows a favorable risk-benefit profile for C1 INH-nf for managing HAE during pregnancy. NCT Identifier: NCT00438815; NCT00462709.

Preprocedural administration of nanofiltered C1 esterase inhibitor to prevent hereditary angioedema attacks.

Patients with hereditary angioedema (HAE) may have attacks triggered by dental, medical, or surgical procedures. This analysis evaluated the efficacy and safety of preprocedural administration of nanofiltered C1 esterase inhibitor (C1 INH-nf; human) for the prevention of HAE attacks during and after dental, medical, or surgical procedures. Data were reviewed retrospectively from two acute treatment trials in which at least 1000 U of C1 INH-nf was administered i.v. within 24 hours before an emergency or noncosmetic medical, surgical, or dental procedure. Dosing data, HAE attacks reported within 72 hours, and adverse events (AEs) reported within 7 days after a preprocedural dose of C1 INH-nf were analyzed to assess efficacy and safety. Forty-one unique subjects (8 children and 33 adults) received C1 INH-nf for 91 procedures (40 in children and 51 in adults). The majority of procedures (56%) involved dental work and 44% involved a variety of surgical or medical procedures. A single 1000-U dose of C1 INH-nf was administered for 96% of procedures. An HAE attack did not occur within 72 hours after C1 INH-nf dosing for 98% (89/91) of procedures. Two HAE attacks were reported after the procedure, and both were treated with C1 INH-nf and achieved relief. None of the reported AEs were judged to be related to C1 INH-nf or were associated with an HAE attack. This analysis supports the efficacy and safety of preprocedural administration of C1 INH-nf for the prevention of HAE attacks.

Oral ganciclovir versus low-dose valganciclovir for prevention of cytomegalovirus disease in recipients of kidney and pancreas transplants.

BACKGROUND: The optimal regimen for prophylaxis of cytomegalovirus (CMV) disease after kidney and/or pancreas transplantation remains unclear. We compared the effectiveness of three months of oral ganciclovir (3 g/day) versus low-dose valganciclovir (450 mg/day) for CMV prophylaxis. METHODS: We performed a retrospective cohort study of patients at our center who received kidney and/or pancreas transplants between January 2000 and April 2003. We used a Cox proportional hazards model to examine the relationship between baseline covariates, including type of CMV prophylaxis, and time to development of CMV disease. RESULTS: Of the 500 patients (295 ganciclovir, 205 valganciclovir), 22 patients (4.4%) developed CMV disease (mean time to CMV disease, 163+/-85 days). Sixteen of the ganciclovir patients (5.4%) and six of the valganciclovir patients (2.9%) developed CMV disease (P=0.18). By CMV serostatus, the incidence of CMV disease during the first posttransplant year was 8.5% among donor-seropositive, recipient-seronegative (D+/R-) patients, 8.6% among D+/R+ patients, 2.9% among D-/R+ patients, 1.0% among D-/R- patients, and 0.9% among patients for whom documentation of CMV serostatus was incomplete. In the unadjusted Cox proportional hazards analysis, race/ethnicity, type of transplant, type of antiviral prophylaxis, CMV serostatus, and use of mycophenolate mofetil were each associated with risk of developing CMV disease. In the adjusted, multivariable model, only CMV serostatus was associated with development of CMV disease. CONCLUSIONS: Three months of low-dose valganciclovir (450 mg/day) was as effective as ganciclovir (3 g/day) for prophylaxis of CMV disease after kidney and/or pancreas transplantation.

Prophylaxis of cytomegalovirus disease in transplant patients.

PURPOSE: A historical perspective and the epidemiology, pathogenesis, and typical patient presentation of cytomegalovirus (CMV) disease in transplant patients; the implications of clinical trials of prophylactic antiviral drug therapy; and unanswered questions about the optimal duration of prophylaxis and the risk of antiviral drug resistance are discussed. SUMMARY: CMV infection and disease are common in transplant patients. They often are the result of transplantation from a CMV-seropositive donor to a CMV-seronegative recipient or reactivation of latent virus in a CMV-seropositive recipient. Reactivation in transplant recipients may be the result of a blunted cytotoxic T-lymphocyte response and an imbalance in the release of pro-inflammatory and anti-inflammatory cytokines. CMV disease develops in many infected patients and frequently involves the graft. Antiviral drug therapies reduce the risk of and delay the onset of CMV disease in transplant recipients. They also reduce the risk of graft injury. CONCLUSION: The optimal duration of antiviral drug prophylaxis in transplant patients remains to be determined; however, it is clear that antiviral prophylaxis can prevent CMV disease as well as many of the complications associated with CMV disease.

Nanofiltered C1 esterase inhibitor for treatment of laryngeal attacks in patients with hereditary angioedema.

BACKGROUND: Laryngeal edema is a life-threatening manifestation of hereditary angioedema (HAE), an autosomal-dominant disorder caused by quantitative or functional C1 esterase inhibitor (C1 INH) deficiency. The preparation of nanofiltered C1 INH (C1 INH-nf) used in this study is indicated for routine prophylaxis against angioedema attacks in the United States and for treatment, preprocedure prevention, and routine prevention of HAE in Europe. The objective of this analysis was to evaluate the effectiveness and tolerability of C1 INH-nf when used for the treatment of laryngeal attacks. METHODS: A post hoc analysis of an open-label treatment study evaluated the effectiveness of C1 INH-nf in the treatment of laryngeal attacks in patients with HAE. Outcomes included unequivocal or clinical relief rates and time from treatment to onset of relief. Data were compiled from this and three other studies for post hoc dosing and tolerability analyses. In all studies, C1 INH-nf at 1000 U was administered i.v., with a second 1000-U dose given after 60 minutes if indicated. RESULTS: In the open-label treatment study, 60 (50/84) and 77% (65/84) of attacks achieved unequivocal relief within 1 and 4 hours, respectively, after treatment. Time to unequivocal relief was shorter with prompt treatment. When C1 INH-nf was administered within 4 hours of symptom onset, clinical relief was achieved in 94% (45/48) of attacks within 4 hours after treatment. Of 265 attacks from the four studies, 62% received two 1000-U doses of C1 INH-nf. No serious adverse events occurring within 7 days after treatment were attributed to study drug, and only one patient required intubation after receiving C1 INH-nf (14.5 hours after symptom onset). CONCLUSION: This analysis supports that C1 INH-nf is an effective and well-tolerated therapy for laryngeal angioedema attacks.

Gene expression profiling of the donor kidney at the time of transplantation predicts clinical outcomes 2 years after transplantation.

We have previously demonstrated that biomarkers of inflammation and immune activity detected within intraoperative renal transplant allograft biopsies are linked to adverse short-term post-transplantation clinical outcomes. Now we provide a post hoc analysis of our earlier data in the light of longer clinical follow-up. A total of 75 consecutively performed renal allografts were analyzed for gene expression of proinflammatory molecules, inflammation-induced adhesion molecules, and antiapoptotic genes expressed 15 minutes after vascular reperfusion to determine whether this analysis can aid in predicting long-term quality of renal function, proteinuria, graft loss, and death-censored graft. We have built predictive models for proteinuria (area under the curve = 0.859, p = 0.0001) and graft loss (area under the curve = 0.724, p = 0.027) 2 years post-transplantation using clinical variables in combination with intragraft gene expression data of tumor necrosis factor-alpha, interleukin-6, CD40, CD3, and tumor necrosis factor-alpha, Bcl-2, and interferon-gamma, respectively. This post hoc analysis demonstrates that hypothesis-driven, targeted polymerase chain reaction profiling of gene expression in the donor kidney at the time of engraftment can predict 2-year post-transplantation clinical outcomes.

Renal allograft failure predictors after PAK transplantation: results from the New England Collaborative Association of Pancreas Programs.

BACKGROUND: The reasons for kidney allograft failure subsequent to pancreas after kidney (PAK) are multifactorial; therefore, we examined these factors to identify a meaningful risk assessment that could assist in patient selection. METHODS: Five transplant centers in New England collaborated for this multiinstitutional retrospective study of 126 PAK transplantation recipients who had a functioning pancreas allograft 7 days after transplantation. Host factors (age at pancreas transplant, gender, body weight, glomerular filtration rate at 3 months pre-PAK and at 3-, 6-, 9-, and 12-month post-PAK, presence of proteinuria, pre- or post-PAK kidney rejection, pancreas rejection, cytomegalovirus disease, and HbA1C at 6-month post-PAK) and transplant factors (time to PAK, use of induction antibody therapy, and combinations of immunosuppressive medications) were assessed in both univariate and multivariate analyses for the primary outcome of kidney allograft failure. RESULTS: Of the variables assessed, factors associated with kidney allograft loss after PAK include impaired renal function in the 3 months before PAK, proteinuria, the occurrence of a post-PAK kidney rejection episode, and interval between kidney and pancreas transplantation more than 1 year. CONCLUSIONS: In our analysis, post-PAK kidney allograft loss was strongly associated with glomerular filtration rate less than 45 mL/min pre-PAK, K to P interval of over 1 year, pre-PAK kidney rejection episode, and pre-PAK proteinuria. Diabetic candidates for PAK with any of these conditions should be counseled regarding the risk of post-PAK renal transplant failure.

Cytomegalovirus in transplantation - challenging the status quo.

BACKGROUND: Cytomegalovirus (CMV) infection of solid organ transplant (SOT) recipients causes both ''direct'' and ''indirect'' effects including allograft rejection, decreased graft and patient survival, and predisposition to opportunistic infections and malignancies. Options for CMV prevention include pre-emptive therapy, whereby anti-CMV agents are administered based on sensitive viral assays, or universal prophylaxis of all at-risk patients. Each approach has advantages and disadvantages in terms of efficacy, costs, and side effects. Standards of care for prophylaxis have not been established. METHODS: A committee of international experts was convened to review the available data regarding CMV prophylaxis and to compare preventative strategies for CMV after transplantation from seropositive donors or in seropositive recipients. RESULTS: Pre-emptive therapy requires frequent monitoring with subsequent treatment of disease and associated costs, while universal prophylaxis results in greater exposure to potential toxicities and costs of drugs. The advantages of prophylaxis include suppressing asymptomatic viremia and prevention of both direct and indirect effects of CMV infection. Meta analyses reveal decreased in mortality for patients receiving CMV prophylaxis. Costs associated with prophylaxis are less than for routine monitoring and pre-emptive therapy. The optimal duration of antiviral prophylaxis remains undefined. Extended prophylaxis may improve clinical outcomes in the highest-risk patient populations including donor-seropositive/recipient-seronegative renal transplants and in CMV-infected lung and heart transplantation. CONCLUSIONS: Prophylaxis is beneficial in preventing direct and indirect effects of CMV infection in transplant recipients, affecting both allograft and patient survival. More studies are necessary to define optimal prophylaxis regimens.

Gene silencing in the endocrine pancreas mediated by short-interfering RNA.

OBJECTIVES: RNA interference as mediated by short-interfering RNA (siRNA) offers a nonviral means to silence genes in tissue; however, few data exist about gene therapy using siRNA in pancreas tissue. To determine if siRNA treatment could silence an endogenous gene in pancreatic islets, we developed a murine model using the endocrine pancreas. METHODS: The insulin 2 (Ins2) gene was targeted with siRNA, and quantitative RT-PCR, fluorescent microscopy, and FACS were used to measure transcript levels and siRNA cellular uptake and transfection efficiency. Isolated pancreatic islets were transfected with siRNA in vitro using a liposomal delivery method in a dose titration (50-400 nM) or pooled from BALB/c mice having received siRNA (100 microg) via hydrodynamic tail vein injection. RESULTS: The Ins2 transcript level was significantly reduced by 55% in vitro with FACS data showing a transfection efficiency over 45% with the 400 nM concentration. In vivo delivery of siRNA to pancreatic islets revealed a 33% reduction in Ins2 mRNA levels, although siRNA was able to be detected in 19% of isolated islet cells. CONCLUSION: We have successfully used RNA interference to silence an endogenous tissue-specific gene (Ins2) in pancreatic islets when transfected in vitro or administered in vivo.

On the intraoperative molecular status of renal allografts after vascular reperfusion and clinical outcomes.

Many hypothesize that subtle inflammation and immune activity detected in the intraoperative period are linked to adverse postkidney transplant clinical outcomes. To this end, renal allografts were analyzed for expression of pro-inflammatory, inflammation-induced adhesion molecules, immune activation as well as anti-apoptotic genes expressed 15 min after vascular reperfusion (zero-hour) to determine whether this analysis can aid in predicting the occurrence of delayed graft function (DGF), acute rejection (AR), and the quality of graft function at 6 mo. Intraoperative biopsies were obtained from 75 consecutively performed renal allografts in which consent was obtained 15 min after vascular reperfusion. These biopsies were analyzed by quantitative real-time PCR for transcription of 15 select genes and by standard histopathology. Posttransplant clinical outcomes were also analyzed in respect to intraoperative transcriptional profiles and clinical parameters available at the time of transplantation. This study demonstrates that a limited and hypothesis-driven PCR-based transcriptional profile of the zero-hour kidney biopsy predicts posttransplant clinical outcomes including DGF, early AR, and the quality of renal function 6 mo posttransplantation. For some clinical endpoints, the combined use of molecular analysis and established clinical indicators available at the time of transplantation further enhances the quality of prognosis. The transcriptional profiling data provide absolutely essential data to the predictive models, particularly with respect to AR and renal function 6 mo posttransplantation.

Enteric drainage of a pancreas allograft is safe for patients with celiac sprue.

Enteric drainage of exocrine secretions in whole organ pancreas transplantation is generally avoided in patients with pre-existing small bowel disease; however, bladder drainage is associated with a 20% rate of urinary tract-related complications. This is a case report of a type 1 diabetic patient with celiac sprue and renal failure. We performed a simultaneous cadaveric kidney pancreas transplant enterically draining the exocrine pancreas. There were no complications. The patient is now more than 6 months post-transplant with excellent function of both renal and pancreas allografts. We conclude that enteric drainage of pancreas allografts in patients with celiac sprue may be performed safely. Whole organ pancreas transplantation is being performed with greater success than ever before, mostly as a result of lessons learned from past experience (1). Enteric drainage of allograft exocrine secretions is preferred for simultaneous pancreas/kidney (SPK) recipients to avoid urinary tract complications associated with bladder drainage. However, most agree that diabetics with pre-existing bowel disease should have bladder drainage of allograft exocrine secretions, so as to prevent the devastating complication of a bowel leak. We describe here a successful case of enteric drainage of an SPK transplant in a patient with celiac sprue. We believe that, when carefully performed, enteric drainage of pancreas allografts is a safe approach for diabetic patients with celiac sprue, and may avert the serious complications associated with bladder drainage.