A Double-Blind, Double-Dummy, Flexible-Design Randomized Multicenter Trial: Early Safety of Single- Versus Divided-Dose Rabbit Anti-Thymocyte Globulin Induction in Renal Transplantation.

A previous nonblinded, randomized, single-center renal transplantation trial of single-dose rabbit anti-thymocyte globulin induction (SD-rATG) showed improved efficacy compared with conventional divided-dose (DD-rATG) administration. The present multicenter, double-blind/double-dummy STAT trial (Single dose vs. Traditional Administration of Thymoglobulin) evaluated SD-rATG versus DD-rATG induction for noninferiority in early (7-day) safety and tolerability. Ninety-five patients (randomized 1:1) received 6 mg/kg SD-rATG or 1.5 mg/kg/dose DD-rATG, with tacrolimus-mycophenolate maintenance immunosuppression. The primary end point was a composite of fever, hypoxia, hypotension, cardiac complications, and delayed graft function. Secondary end points included 12-month patient survival, graft survival, and rejection. Target enrollment was 165 patients with an interim analysis scheduled after 80 patients. Interim analysis showed primary end point noninferiority of SD-rATG induction (p = 0.6), and a conditional probability of <1.73% of continued enrollment producing a significant difference (futility analysis), leading to early trial termination. Final analysis (95 patients) showed no differences in occurrence of primary end point events (p = 0.58) or patients with no, one, or more than one event (p = 0.81), or rejection, graft, or patient survival (p = 0.78, 0.47, and 0.35, respectively). In this rigorously blinded trial in adult renal transplantation, we have shown SD-rATG induction to be noninferior to DD-rATG induction in early tolerability and equivalent in 12-month safety. (Clinical Trials.gov #NCT00906204.).

Apolipoprotein L1 gene variants in deceased organ donors are associated with renal allograft failure.

Apolipoprotein L1 gene (APOL1) nephropathy variants in African American deceased kidney donors were associated with shorter renal allograft survival in a prior single-center report. APOL1 G1 and G2 variants were genotyped in newly accrued DNA samples from African American deceased donors of kidneys recovered and/or transplanted in Alabama and North Carolina. APOL1 genotypes and allograft outcomes in subsequent transplants from 55 U.S. centers were linked, adjusting for age, sex and race/ethnicity of recipients, HLA match, cold ischemia time, panel reactive antibody levels, and donor type. For 221 transplantations from kidneys recovered in Alabama, there was a statistical trend toward shorter allograft survival in recipients of two-APOL1-nephropathy-variant kidneys (hazard ratio [HR] 2.71; p = 0.06). For all 675 kidneys transplanted from donors at both centers, APOL1 genotype (HR 2.26; p = 0.001) and African American recipient race/ethnicity (HR 1.60; p = 0.03) were associated with allograft failure. Kidneys from African American deceased donors with two APOL1 nephropathy variants reproducibly associate with higher risk for allograft failure after transplantation. These findings warrant consideration of rapidly genotyping deceased African American kidney donors for APOL1 risk variants at organ recovery and incorporation of results into allocation and informed-consent processes.

Similar results with solitary pancreas transplantation compared with simultaneous pancreas-kidney transplantation in the new millennium.

INTRODUCTION: The purpose of this study was to analyze our single-center outcomes according to pancreas transplant (PT) category in the new millennium by using standardized management protocols. PATIENTS AND METHODS: We retrospectively studied 202 consecutive PTs (179 with portal-enteric drainage) in 192 patients; all received either rabbit antithymocyte globulin or alemtuzumab induction in combination with tacrolimus, mycophenolate mofetil, and tapered corticosteroids or early steroid withdrawal. Unlike simultaneous pancreas/kidney (SPK) transplant, solitary PT (SPT) recipients were managed with routine perioperative anticoagulation and surveillance pancreas biopsies. RESULTS: From November 2001 to March 2013, we performed 162 SPK transplants, 35 pancreas after kidney transplants, and 5 pancreas-alone transplants (40 SPTs). Demographic characteristics were mostly comparable; however, the SPT group had younger donors, shorter waiting time, fewer HLA mismatches, and fewer African-American recipients but more retransplants (all, P < .05). With a mean follow-up of 5.5 versus 7.5 years, overall patient (86.4% SPK vs 86.8% SPT), kidney graft (74% SPK vs 80% SPT), and pancreas graft (both 65%) survival rates were comparable. Although mortality rates were similar, mortality patterns differed because no SPT recipients died early, whereas the 1-, 3-, and 5-year mortality rates after SPK transplant were 4%, 9% and 12%, respectively (P < .05). The most common causes of pancreas graft loss were death with functioning grafts in SPK recipients and acute/chronic rejection in SPT recipients. Rates of early thrombosis were 8.6% in SPK patients and 5% in SPT patients. Cumulative clinical acute rejection rates were similar between groups (SPK 29% vs SPT 27.5%; P = NS). CONCLUSIONS: In the setting of depleting antibody induction and tacrolimus-based therapy, HLA matching, careful donor and recipient selection, portal-enteric drainage, selective perioperative anticoagulation, and surveillance SPT biopsy monitoring, similar medium-term outcomes can be achieved in SPK transplants and SPTs in the new millennium.

5-year results of a prospective, randomized, single-center study of alemtuzumab compared with rabbit antithymocyte globulin induction in simultaneous kidney-pancreas transplantation.

INTRODUCTION: The study purpose was to analyze 5-year outcomes in a prospective, randomized trial of alemtuzumab (ALEM) versus rabbit antithymocyte globulin (rATG) induction in simultaneous kidney-pancreas transplantation (SKPT). PATIENTS AND METHODS: From February 2005 through October 2008, a total of 46 SKPTs (45 portal-enteric drainage) were prospectively randomized to receive either single-dose ALEM (30 mg intraoperatively) or multiple-dose rATG antibody induction (starting intraoperatively, minimum of 3 doses administered) with tacrolimus/mycophenolate and/or steroids. RESULTS: Of 222 kidney transplant patients enrolled in the study, 46 received SKPTs; 28 (61%) received ALEM and 18 (39%) received rATG induction. Follow-up ranged from 54 to 98 months (mean, 69 months). There were no significant differences between the 2 groups in 5-year patient (82% ALEM vs 89% rATG), kidney graft (79% ALEM vs 72% rATG), or pancreas graft (64% ALEM vs 56% rATG) survival rates. Death-censored kidney (90% ALEM vs 75% rATG) and pancreas (71% ALEM vs 56% rATG) graft survival rates were likewise comparable (both, P = NS). Acute rejection (21% ALEM vs 44% rATG; P = .11) and major infection (39% ALEM vs 67% rATG; P = .13) rates were slightly lower in the ALEM group; cytomegalovirus infections were significantly lower (0% ALEM vs 17% rATG; P = .05). The incidence of late acute rejection was low in both groups. There were no differences in early pancreas thromboses (3.6% ALEM vs 11% rATG), postoperative bleeding (11% ALEM vs 0% rATG), other surgical complications, or readmissions between groups. In patients with functioning grafts, 5-year mean serum creatinine (1.4 ALEM vs 1.6 mg/dL rATG), calculated abbreviated Modification of Diet in Renal Disease glomerular filtration rate (55 ALEM vs 52 mL/min/1.73 m(2) rATG), glycosylated hemoglobin (both 5.4%), and C-peptide (2.2 ALEM vs 2.3 ng/mL rATG) levels were similar. CONCLUSIONS: Single-dose ALEM and multiple dose rATG induction provided similar medium-term patient, kidney, and pancreas graft function and survival rates. ALEM induction may be associated with less acute rejection and major infection over the long term.

New alginate microcapsule system for angiogenic protein delivery and immunoisolation of islets for transplantation in the rat omentum pouch.

Severe hypoxia caused by a lack of vascular supply and an inability to retrieve encapsulated islets transplanted in the peritoneal cavity for biopsy and subsequent evaluation are obstacles to clinical application of encapsulation strategies for islet transplantation. We recently proposed an omentum pouch model as an alternative site of encapsulated islet transplantation and have also described a multi-layer microcapsule system suitable for coencapsulation of islets with angiogenic protein in which the latter could be encapsulated in an external layer to induce vascularization of the encapsulated islet graft. The purpose of the present study was to determine the angiogenic efficacy of fibroblast growth factor (FGF-1) released from the external layer of the new capsule system in the omentum pouch graft. We prepared 2 groups of alginate microspheres, each measuring ∼600 µm in diameter with a semipermeable poly-L-ornithine (PLO) membrane separating 2 alginate layers. While one group of microcapsules contained no protein (control), FGF-1 (1.794 µg/100 microcapsules) was encapsulated in the external layer of the other (test) group. From each of the 2 groups, 100 microcapsules were transplanted separately in an omentum pouch created in each normal Lewis rat and were retrieved after 14 days for analysis of vessel density using the technique of serial sample sections stained for CD31 with quantitative three-dimensional imaging. We found that FGF-1 released from the external layer of the test microcapsules induced a mean ± SD vessel density (mm(2)) of 198.8 ± 59.2 compared with a density of 128.9 ± 10.9 in pouches measured in control capsule implants (P = .03; n = 5 animals/group). We concluded that the external layer of our new alginate microcapsule system is an effective drug delivery device for enhancement of graft neovascularization in a retrievable omentum pouch.

Donor-recipient relationships in African American vs. Caucasian live kidney donors.

PURPOSE: The purpose of the study was to characterize differences in donor and recipient relationships between African American (AA) and Caucasian living kidney donors. METHODS: Data from all successful living kidney donors at a single institution between 1991 and 2009 were reviewed. Relationships between donor and recipient were categorized and between-group comparisons performed. RESULTS: The study sample consisted of 73 (18%) AA and 324 Caucasian living kidney donors. The distribution of donor-recipient relationships differed significantly between AA and Caucasians. AA donors were more likely to be related to the recipient (88% vs. 74%, p = 0.007) than Caucasians. AA donors were more likely to participate in child to parent donation and were less likely to participate in parent to child donation or to donate to unrelated individuals. Sibling and spousal donations were similar in both groups. Caucasian donors were more likely to be unrelated to the recipient than AA donors. CONCLUSIONS: Differences exist in donor-recipient relationships between AA and Caucasian living kidney donors. Future studies exploring cultural differences and family dynamics may provide targeted recruitment strategies for AA and Caucasian living kidney donors. Living unrelated kidney transplantation appears to be a potential growth area for living kidney donation in AA.

Renal allograft failure due to emphysematous pyelonephritis: successful non-operative management and proposed new classification scheme based on literature review.

Emphysematous pyelonephritis (EPN) is a rare necrotizing infection of the kidney caused by gas-forming organisms, usually occurs in diabetic patients, and often requires nephrectomy for effective therapy. EPN is rarely reported in renal allografts, with only 20 cases found in the English literature. We report herein a case of EPN in a transplanted kidney resulting in acute renal failure and sepsis. The patient was managed non-operatively with subsequent recovery of renal allograft function. Based on this experience and a review of the literature, we suggest an amended classification system for EPN in kidney transplantation to plan and guide treatment options accordingly. However, the scarcity of this disease process, coupled with the lack of prospective validation of the new classification scheme, prevents drawing definitive conclusions regarding optimal management strategies including the role and timing of allograft nephrectomy.

Short-term renal outcomes in African American and Caucasian donors following live kidney donation.

INTRODUCTION: Although African Americans (AA) are considered higher risk kidney donors than Caucasians, limited data are available regarding outcomes of AA donors. METHODS: We performed a single-center retrospective review of all kidney donors from 1993 to 2007 and evaluated race/ethnic differences in post-donation changes in renal function, incident proteinuria, and systolic blood pressure (SBP) using linear mixed models. RESULTS: A total of 336 kidney donors (63 AA, 263 Caucasian, 10 other) were evaluated. Before donation, AA had higher serum creatinine concentrations, estimated glomerular filtration rate (GFR) values, and SBP levels than Caucasians. No significant changes in SBP or renal function were observed between the two groups within the first year after donation, although results were limited by incomplete follow-up. CONCLUSION: AA had higher pre-donation serum creatinine, GFR, and SBP values compared to Caucasians; however, the degree of change in renal function and blood pressure did not differ between groups following kidney donation. Although long-term studies are needed, our study suggests that AA and Caucasians experience similar short-term consequences after donation. The incomplete data available on donor outcomes in our center and in prior publications also indicates a global need to implement systems for structured follow-up of live kidney donors.

Potential donor-recipient MYH9 genotype interactions in posttransplant nephrotic syndrome after pediatric kidney transplantation.

Recurrence of focal segmental glomerulosclerosis (FSGS) with nephrotic syndrome is relatively common after kidney transplantation in young recipients whose predialysis course consists of heavy proteinuria, hypertension and subacute loss of kidney function. The gene(s) mediating this effect remain unknown. We report an unusual circumstance where kidneys recovered from a deceased African American male donor with MYH9-related occult FSGS (risk variants in seven of eight MYH9 E1 haplotype single nucleotide polymorphisms) were transplanted into an African American male child with risk variants in four MYH9 E1 risk variants and a European American female teenager with two MYH9 E1 risk variants. Fulminant nephrotic syndrome rapidly developed in the African American recipient, whereas the European American had an uneventful posttransplant course. The kidney donor lacked significant proteinuria at the time of organ procurement. This scenario suggests that donor-recipient interactions in MYH9, as well as other gene-gene and gene-environment interactions, may lead to recurrent nephrotic syndrome after renal transplantation. The impact of transplanting kidneys from donors with multiple MYH9 risk alleles into recipients with similar genetic background at high risk for recurrent kidney disease needs to be determined.

Impact of race and gender on live kidney donation.

BACKGROUND: African Americans (AA) and women are less likely to receive a live kidney donor (LKD) transplant than Caucasians or men. Reasons for non-donation are poorly understood. METHODS: A retrospective review of 541 unsuccessful LKD was performed to explore reasons for non-donation and to assess for racial and/or gender differences. RESULTS: We identified 138 AA and 385 Caucasian subjects who volunteered but did not successfully donate. Females (58.2%) were more likely to be excluded than males due to reduced renal function (glomerular filtration rate < 85 mL/min, 7.9% vs. 0.9%, p < 0.0001) or failure to complete the evaluation (6.4% vs. 1.8%, p = 0.01). AA were more commonly excluded due to obesity (body mass index >or= 32 kg/m(2); 30.4% AA vs. 16.6% Caucasian, p = 0.0005) or failure to complete the evaluation (12.3% AA vs. 1.8% Caucasian, p < 0.0001) whereas Caucasians were more often excluded due to kidney stones (1.5% AA vs. 7.3% Caucasian, p = 0.01). CONCLUSIONS: Significantly different reasons for exclusion of LKD exist between potential Caucasian and AA LKD, particularly among women. Among the differences that we observed are potentially modifiable barriers to donation including obesity and failure to complete the donor evaluation. A further understanding of these barriers may help point to strategies for more effective recruitment and successful LKD.

Outcomes of extended donors in pancreatic transplantation with portal-enteric drainage.

OBJECTIVE: Limited data are available on extended (EX) donor criteria in pancreatic transplantation (PTX). METHODS: This retrospective study from February 2007 through April 2007 compared 2 cohorts of simultaneous kidney-pancreas transplantations (SKPT): the first from EX donors, which were defined as age <10 years or > or =45 years, or donation after cardiac death [DCD]), and the second from conventional (CONV) donors. RESULTS: Among 79 SKPT, 19 (24%) were from EX donors (12 older than age 45 [mean age, 50.2 years], 3 pediatric donors <10, and 4 DCD donors) and the remaining 60 SKPT from CONV donors. The mean donor age was higher in EX than CONV donors (38 vs 25 years, P < .05). There were no other differences between the 2 cohorts. With a similar median follow-up of 29 months, patient, kidney and pancreatic graft survival rates were 89%, 89%, and 79%, for the EX, whereas corresponding outcomes for CONV donors were 93%, 87%, and 80%, respectively (all P = NS). The incidences were similar for delayed kidney graft function (5% in each group), early pancreatic graft loss due to thrombosis (5% EX vs 8% CONV donors), acute rejection (16% EX vs 18% CONV donors), surgical complications, and infections. There were no significant differences in 1-year mean serum creatinine (1.4 mg/dL in each group) or glycohemoglobin (5.2% vs 5.5%) levels between the EX and CONV donor groups, respectively. CONCLUSION: Short-term outcomes among SKPT from selected EX donors were comparable to CONV donors. Donors at the extremes of age and DCD donors may represent underused resources in SKPT.

Analysis of bacteremia after pancreatic transplantation with enteric drainage.

OBJECTIVE: The objective of this study was to review the incidence, risk factors, and impact of bacteremia after pancreas transplantation (PTX). METHODS: We performed a retrospective analysis of consecutive simultaneous kidney-pancreas transplantations (SKPTs) and solitary PTXs from January 2002 through April 2007. Positive blood cultures were correlated with other coexisting infections and parameters. RESULTS: One hundred ten PTXs with enteric drainage included 80 SKPTs and 30 solitary PTXs. Mean follow-up was 32 months. Bacteremia occurred in 29 (26%) patients with 5 (17%) being recurrent; it was seen during the first month after transplantation in 13 (12%), between 1 and 3 months in 12 (11%), between 3 and 12 months in 3 (3%), and after the first year in 3 cases (3%). Typical organisms were as follows: MRSE, MSSE, Klebsiella, Escherichia coli, vancomycin-resistant enterococci (VRE), and Acinetobacteri. Bacteremia was associated with coexisting site infection in 20 cases (69%): deep abdominal wound (31%); line (31%); urinary tract (34%); and pulmonary (7%). Similar bacterial species in blood and a coexisting site occurred in 15 cases (52%). No correlation was seen with cytomegalovirus (CMV) infections. In the first year, bacteremia was associated with more acute rejection episodes (32% vs 17%; P = .09), surgical complications (54% vs 42%; P = .267), mortality (11% vs 4%; P = .15), and death-censored pancreatic (14% vs 9%; P = .39) and kidney (4% vs 0; P = .08) graft loss. Fewer patients with bacteremia received alemtuzumab compared with rATG induction (14% vs 39%; P = .04). CONCLUSIONS: Bacteremias were common within 3 months of PTX. A significant number (39%) were multidrug resistant. The majority were accompanied by abdominal, urinary, or line infections. Bacteremias were associated with slightly higher incidences of rejection, mortality, and graft loss.

Do pretransplant C-peptide levels influence outcomes in simultaneous kidney-pancreas transplantation?

OBJECTIVE: To analyze outcomes in simultaneous kidney-pancreas transplantation (SKPT) recipients who retain C-peptide production at the time of SKPT. METHODS: This retrospective analysis of SKPTs from January 2002 through January 2007 compared outcomes between patients with absent or low C-peptide levels (<2.0 ng/mL, group A) with those having levels > or =2.0 ng/mL (group B). RESULTS: Among 74 SKPTs, 67 were in group A and seven in group B (mean C-peptide level 5.7 ng/mL). During transplantation, group B subjects were older (mean age 51 vs 41 years, P = .006); showed a later age of onset of diabetes (median 35 vs 13 years, P = .0001); weighed more (median 77 vs 66 kg, P = .24); had a greater proportion of African-Americans (57% vs 13%, P = .004); and had a longer pretransplant duration of dialysis (median 40 vs 14 months, P = .14). With similar median follow-up of 40 months, death-censored kidney (95% group A vs 100% group B, P = NS) and pancreas (87% group A vs 100% group B, P = NS) graft survival rates were similar, but patient survival (94% group A vs 71% group B, P = .03) was greater in group A. At 1-year follow-up, there were no significant differences in rejection episodes, surgical complications, infections, readmissions, hemoglobin A1C or C-peptide levels, serum creatinine, or MDRD GFR levels. CONCLUSIONS: Diabetic patients with measurable C-peptide levels before transplant were older, overweight, more frequently African-American and had a later age of onset of diabetes, longer duration of pretransplant dialysis, and reduced patient survival compared to insulinopenic patients undergoing SKPT. The other outcomes were similar.

Successful simultaneous kidney-pancreas transplantation from extreme donors.

UNLABELLED: The purpose of this study was to retrospectively review our experience with "extreme" pancreas donors compared to conventional (CONV) donors. METHODS: "Extreme" (EX) pancreas donors were defined as deceased donors (DDs) age >50 years, <8 years, donation after cardiac death (DCD), and targeted for organ discard. RESULTS: From January 2002 through January 2005, we performed 40 simultaneous kidney-pancreas transplants (SKPT) with Thymoglobulin induction, including 9 (22.5%) from EX and 31 from CONV DDs. Mean DD age was higher in EX DD (41.2 years EX vs 26.0 CONV, P < .05), but mean recipient age and cold ischemia times did not differ between groups. With a mean follow-up of 16.8 months in the EX DD group, patient and kidney graft survival rates are both 100%, and the pancreas graft survival rate is 89%. With a mean follow-up of 21.7 months in the CONV DD group, patient and kidney graft survival rates are both 93.5% and the pancreas graft survival rate is 77.4%. All patients with surviving grafts exhibited good initial (1 case of delayed kidney graft function in a CONV DD) and stable long-term kidney and pancreas graft function. Mean length of initial hospital stay and the incidences of acute rejection, readmissions, operative complications, and infections were similar between groups. CONCLUSIONS: The results of this study suggest that the limits of donor acceptability continue to evolve as excellent outcomes can be achieved in SKPTs from selected EX DDs.

Experience with alternate-day thymoglobulin induction in pancreas transplantation with portal-enteric drainage.

The purpose of this study was to retrospectively review outcomes in patients undergoing pancreas transplantation (PTX) with a novel induction protocol of alternate-day thymoglobulin (rATG) in combination with tacrolimus (TAC), mycophenolate mofetil (MMF), and steroids. From January 2002 through January 2005, we performed 55 PTXs in 53 patients. The first dose of rATG (1.5 mg/kg) was given intraoperatively, and subsequent doses were given on alternate days until therapeutic TAC levels (>8 ng/mL) were achieved. All patients underwent PTX with enteric drainage, including 51 with portal and 4 with systemic venous drainage. Patients received a minimum of 2 and maximum of 6 doses of rATG induction (median 3 doses). The patient group had a mean age of 42.8 years and included 40 simultaneous kidney-PTX, 11 sequential PTX after kidney, and 4 PTX-alone transplant recipients. Patient, kidney, and pancreas graft survival rates are 96%, 96%, and 84%, respectively, with a mean follow-up of 21 months. The incidence of acute rejection was 18%; there were no graft losses due to isolated acute rejection. The incidence of infection was 60%, but there were no cases of polyomavirus or Epstein-Barr virus infection and only 6 cases (11%) of cytomegalovirus infection. The composite endpoint of no rejection, graft loss, or mortality was attained by 71% of patients. At present, 94% of surviving patients are both dialysis and insulin-free, including 5 successful PTX retransplants. These findings suggest that PTX with portal-enteric drainage and alternate day rATG induction may result in excellent intermediate-term outcomes.

Pilot study of rapid steroid elimination with alemtuzumab induction therapy in kidney and pancreas transplantation.

This study evaluates our initial experience using alemtuzumab induction with rapid corticosteroid elimination in kidney (KTX) and pancreas transplant (PTX) patients. Data were collected retrospectively for all patients who received single-dose alemtuzumab (30 mg IV intraoperatively) with steroid pretreatment and a control group who received alternate day rabbit antithymocyte globulin (rATG) induction with a steroid-based regimen. Patients in both groups received tacrolimus (TAC) and mycophenolate mofetil (MMF). There were 16 patients in each group, including 9 deceased donor KTXs, 5 living donor KTXs, 1 simultaneous K-PTX, and 1 sequential PTX after KTX. Demographic, immunologic, and transplant characteristics were similar between groups. Nine patients (56%) in the alemtuzumab group compared to five (25%) in the control group developed neutropenia requiring MMF or valganciclovir dose reduction (or both). Absolute lymphocyte counts at 3 months were 340 +/- 200/mm3 and 890 +/- 544/ mm3 in the alemtuzumab and control groups, respectively (P = .001). There were two biopsy-proven acute rejection episodes (12.5%) in each group, and no difference in the incidence of infection. Creatinine clearance at 6 months was 58 mL/min in each group. Patient and kidney graft survival rates were both 94% in the alemtuzumab group (one death from cardiac arrest), compared with 100% patient and kidney graft survival rates in the control group (P = NS), with a mean follow-up of 9 and 11 months, respectively. The results of this pilot study suggest that similar short-term outcomes can be achieved using a rapid steroid elimination protocol with alemtuzumab induction therapy compared to rATG with steroids in patients receiving TAC and MMF maintenance therapy.

Pulsatile pump perfusion of pancreata before human islet cell isolation.

Machine pulsatile perfusion for whole pancreas preservation might improve yield, viability, and function of human islets recovered after prolonged cold ischemia times. Four human pancreata were procured from cadaver donors (1 non-heart-beating donor) and stored in cold University of Wisconsin (UW) solution for a mean 13 hours prior to placement on a machine pulsatile perfusion device. The four pancreata were perfused for 4 hours with UW solution before undergoing islet isolation. Islets were quantified, viability was assessed, and insulin secretion was measured. Results were compared with nonpumped islet isolations stratified for cold ischemia time (CIT) <8 hours or cold ischemia time >8 hours. The islet yield for the four pumped pancreata was 3435 (+/-1951) islet equivalents/gram pancreas tissue (IEQ/g), compared with a mean yield of 5134 (+/-2700) IEQ/g and 2640 (+/-1000) IEQ/g from pancreas with <8 hours and >8 hours CIT, respectively. The mean viability after machine pulsatile perfusion was 86% (vs 74% and 74% for the <8 hour and >8 hour CIT groups). The mean viable yield (total yield x viability) was 2937 IEQ/g for machine perfusion, compared with 3799 IEQ/g and 1937 IEQ/g from pancreata with <8 hours and >8 hours CIT, respectively. The insulin secretion index of islets after machine perfusion was 6.4, compared with indices of 1.9 and 1.8 for the <8 hour and >8 hour CIT groups. This preliminary data indicates that low-flow machine pulsatile perfusion of pancreata with prolonged cold ischemia time can result in excellent yield, viability, and function.

Presence of nonhematopoietic side population cells in the adult human and nonhuman primate pancreas.

UNLABELLED: Side population (SP) cells defined by their ability to efflux Hoechst dye 33342 (Hst), demonstrate functional stem cell capabilities in adult murine tissues and may represent organ-specific stem cells. We examined adult human (Hu) and rhesus macaque (Rh) pancreatic tissue for the presence of SP cells. METHODS: Hu cadaver (n = 4) and Rh donor (n = 5) pancreata were dispersed with collagenase and separated by density gradient centrifugation to relatively enrich fractions for islet, ductal, and acinar tissue in human and islet and nonislet tissue in Rh. Single cell suspensions were incubated with varying Hst concentrations to determine optimal conditions for SP cell analysis. Cellular heterogeneity was assessed using a panel of monoclonal antibodies positive for hematopoietic and/or endothelial cells. RESULTS: Hu SP cells comprised approximately 0.12%, 0.08%, and 0.45% of the gated populations for Hu islet, ductal, and acinar fractions respectively. In Rh, 5.5% and 3.7% of the islet and nonislet fractions were identified as SP cells. FACS analysis of Hu pancreas-derived SP cells indicated that greater than 95% were CD45(-), and only 6% were CD34(+)CD45(-). A similar phenotype was detected in Rh pancreas-derived SP cell populations: greater than 70% were CD45(-) and less than 2% were endothelial lineage positive. CONCLUSIONS: SP cells are found in both islet- and nonislet-enriched fractions of the adult Hu and Rh pancreas. The majority of pancreatic SPs are CD45(-) and CD34(-), suggesting nonhematopoietic lineage. Further preclinical study is needed to establish the phenotype and functional role of adult tissue-specific versus tissue-resident stem cells.

Superiority of portal venous drainage over systemic venous drainage in pancreas transplantation: a retrospective study.

OBJECTIVE: To compare portal and systemic venous drainage of pancreas transplants and demonstrate an immunologic and survival superiority of portal venous drainage. SUMMARY BACKGROUND DATA: Traditionally, solitary pancreas transplants have been performed using systemic venous and bladder drainage, but more recently, the advantages of enteric drainage have been well documented. Although physiologic benefits for portal venous drainage have been described, the impact of portal venous drainage, especially with solitary pancreas transplants, has yet to be determined. METHODS: Since August 1995, 280 pancreas transplants with enteric duct drainage were analyzed. One hundred and seventeen were simultaneous pancreas and kidney (SPK), 63 with systemic venous drainage (SV) and 54 with portal venous drainage (PV). The remainder were solitary transplants; 97 pancreas after kidney (PAK; 42 SV and 55 PV) and 66 transplants alone (PTA; 26 SV and 40 PV). Immunosuppressive therapy was equivalent for both groups. RESULTS: The groups were similar with respect to recipient characteristics and HLA matching. Thirty-six month graft survival for all transplants was 79% for PV and 65% for SV (P =.008). By category, SPK graft survival was 74% for PV and 76% for SV, PAK graft survival was 70% for PV and 56% for SV, and PTA graft survival was 84% for PV and 50% for SV. The rate of at least one rejection episode was also significantly higher in the SV group. At 36 months, for all pancreas transplants, the rejection rate was 21% for PV and 52% for SV (P <.0001). For SPK, rejection rates were 9% for PV and 45% for SV. For PAK, rejection rates were 16% for PV and 65% for SV, and for PTA 36% for PV and 51% for SV. The rejection rates for kidneys following SPK were also lower in the PV group (26% versus 43% for SV). Furthermore, the grades of rejection were milder in PV for all transplants (P =.017). By multivariate analysis, portal venous drainage was the only parameter that significantly affected rejection. CONCLUSION: Graft survival and rejection is superior for PV. These clinical findings are consistent with published reports of experimentally induced portal tolerance and strongly argue that PV drainage should be the procedure of choice for pancreas transplantation.