Renal resistance thresholds during hypothermic machine perfusion and transplantation outcomes - a retrospective cohort study

Renal resistance (RR), of allografts undergoing hypothermic machine perfusion (HMP), is considered a measure of organ quality. We conducted a retrospective cohort study of adult deceased donor kidney transplant (KT) recipients whose grafts underwent HMP. Our aim was to evaluate whether RR is predictive of death-censored graft failure (DCGF). Of 274 KT eligible for analysis, 59% were from expanded criteria donor. RR was modeled as a categorical variable, using a previously identified terminal threshold of 0.4, and 0.2 mmHg/ml/min (median in our cohort). Hazard ratios (HR) of DCGF were 3.23 [95% confidence interval (CI): 1.12-9.34, P = 0.03] and 2.67 [95% CI: 1.14-6.31, P = 0.02] in univariable models, and 2.67 [95% CI: 0.91-7.86, P = 0.07] and 2.42 [95% CI: 1.02-5.72, P = 0.04] in multivariable models, when RR threshold was 0.4 and 0.2, respectively. Increasing risk of DCGF was observed when RR over the course of HMP was modeled using mixed linear regression models: HR of 1.31 [95% CI: 1.07-1.59, P < 0.01] and 1.25 [95% CI: 1.00-1.55, P = 0.05], in univariable and multivariable models, respectively. This suggests that RR during HMP is a predictor of long-term KT outcomes. Prospective studies are needed to assess the survival benefit of patients receiving KT with higher RR in comparison with staying wait-listed.

Magnitude of change in alpha-fetoprotein in response to transarterial chemoembolization predicts survival in patients undergoing liver transplantation for hepatocellular carcinoma

BACKGROUND

Downsizing strategies are often attempted for patients with hepatocellular carcinoma (hcc) before liver transplantation (lt). The objective of the present study was to determine clinical predictors of favourable survival outcomes after transarterial chemoembolization (tace) before lt for hcc outside the Milan criteria, so as to better select candidates for this strategy.

METHODS

In this retrospective study, patients with hcc tumours either beyond Milan criteria (single lesion > 5 cm, 3 lesions with 1 or more > 3 cm) or at the upper limit of Milan criteria (single lesions between 4.1 cm and 5.0 cm), with a predicted waiting time of more than 3 months, received carboplatin-based tace treatments. Exclusion criteria for tace included Child-Pugh C cirrhosis or the presence of portal vein invasion or extrahepatic disease on imaging. Only patients without tumour progression after tace underwent lt.

RESULTS

Of 160 hcc patients who received liver grafts between 1997 and 2010, 35 were treated with tace preoperatively. The median of the sum of tumour diameters was 6.7 cm (range: 4.8-8.5 cm), which decreased with tace to 5.0 cm (range: 3.3-7.0 cm) at transplantation (p < 0.0004). The percentage drop in alpha-fetoprotein (αfp) was a positive predictor (p = 0.0051) and the time from last tace treatment to transplantation was a negative predictor (p < 0.0001) for overall survival.

CONCLUSIONS

The percentage drop in αfp and a shorter time from the final tace treatment to transplantation significantly predicted improved overall survival after lt for hcc downsized with tace. As a serum marker, αfp should be followed when tace is used as a strategy to stabilize or downsize hcc lesions before lt.

Hepatitis C infection and hepatocellular carcinoma in liver transplantation: a 20-year experience

BACKGROUND

Hepatitis C infection (HCV) and hepatocellular carcinoma (HCC), the two main causes of liver transplantation (LT), have reduced survival post-LT. The impact of HCV, HCC and their coexistence on post-LT survival were assessed.

METHODOLOGY

All 601 LT patients from 1992 to 2011 were reviewed. Those deceased within 30 days (n = 69) and re-transplants (n = 49) were excluded. Recipients were divided into four groups: (a) HCC-/HCV-(n = 252) (b) HCC+/HCV- (n = 58), (c) HCC-/HCV+ (n = 106) and (d) HCC+/HCV+ (n = 67). Demographics, the donor risk index (DRI), Model for End-Stage Liver Disease (MELD) score, survival, complications and tumour characteristics were collected. Statistical analysis included anova, chi-square, Fisher's exact tests and Cox and Kaplan-Meier for overall survival.

RESULTS

Groups were comparable with regards to baseline characteristics, but HCC patients were older. After adjusting for age, MELD, gender and the donor risk index (DRI), survival was lower in the HCC+/HCV+ group (59.5% at 5 yrs) and the hazard ratio (HR) was 1.90 [95% confidence interval (CI),1.24-2.95, P = 0.003] and 1.45 (95% CI, 0.99-2.12, P = 0.054) for HCC-/HCV+. HCC survival was similar to controls (HR 1.18, 95% CI, 0.71-1.93, P = 0.508). HCC+/HCV- patients exceeded the Milan criteria (50% versus 31%, P < 0.04) and had more micro-vascular invasion (37.5% versus 20.6%, P = 0.042). HCC+/HCV+ versus HCC+/HCV- survival remained lower (HR 1.94, 95% CI, 1.06-3.81, P = 0.041) after correcting for tumour characteristics and treatment.

CONCLUSION

HCV patients had lower survival post-LT. HCC alone had no impact on survival. Patient survival decreased in the HCC+/HCV+ group and this appears to be as a consequence of HCV recurrence.

Transporting live donor kidneys for kidney paired donation: initial national results

Optimizing the possibilities for kidney-paired donation (KPD) requires the participation of donor-recipient pairs from wide geographic regions. Initially it was envisaged that donors would travel to the recipient center; however, to minimize barriers to participation and simplify logistics, recent trends have involved transporting the kidneys rather than the donors. The goal of this study was to review outcomes of this practice. KPD programs throughout the United States were directly queried about all transplants involving live donor kidney transport. Early graft function was assessed by urine output in the first 8 h, postoperative serum creatinine trend, and incidence of delayed graft function. Between April 27, 2007 and April 29, 2010, 56 live donor kidneys were transported among 30 transplant centers. Median CIT was 7.2 h (IQR 5.5-9.7, range 2.5-14.5). Early urine output was robust (>100 cc/h) in all but four patients. Creatinine nadir was <2.0 mg/dL in all (including the four with lower urine output) but one patient, occurring at a median of 3 days (IQR 2-5, range 1-49). No patients experienced delayed graft function as defined by the need for dialysis in the first week. Current evidence suggests that live donor kidney transport is safe and feasible.

The impact of thymoglobulin on renal function and calcineurin inhibitor initiation in recipients of orthotopic liver transplant: a retrospective analysis of 298 consecutive patients

BACKGROUND

Renal dysfunction remains the Achilles' heel of calcineurin inhibitor (CI)use. The purpose of this study was to assess our institutional, renal-sparing strategy using thymoglobulin (TMG) in recipients of orthotopic liver transplants.

METHODS

We performed a retrospective analysis of data from 298 adult recipients who were transplanted between 1991 and 2002. The patients were divided into two groups: those induced with TMG (group 1) and those that were not treated with this agent (group 2). A subgroup analysis was performed of patients with baseline serum creatinine values above 1.5 mg/dL (group 1A received TMG; group 2A did not). All patients received tacrolimus or cyclosporine (CyA) maintenance immunosuppression.

RESULTS

Indications and demographics were similar between the two groups. Although there was no difference in patient and graft survivals, there was a statistically significant benefit in the rejection-free graft survival at 1 year for group 1 (51% vs 39%; P =.02). Furthermore, serum creatinine at 6 months was lower for group 1, despite a similar baseline creatinine. Subgroup analysis for patients with baseline abnormal serum creatinines showed that group 1A displayed an improved rejection-free graft survival at 1 month but not at 1 year.

CONCLUSIONS

Thymoglobulin induction therapy may allow a delay in the initiation of CI therapy without compromising patient and graft survival, while preventing early rejection, even among patients with baseline renal dysfunction.

The impact of thymoglobulin on renal function and calcineurin inhibitor initiation in recipients of orthotopic liver transplant: a retrospective analysis of 298 consecutive patients

BACKGROUND

Renal dysfunction remains the Achilles' heel of calcineurin inhibitor (CI)use. The purpose of this study was to assess our institutional, renal-sparing strategy using thymoglobulin (TMG) in recipients of orthotopic liver transplants.

METHODS

We performed a retrospective analysis of data from 298 adult recipients who were transplanted between 1991 and 2002. The patients were divided into two groups: those induced with TMG (group 1) and those that were not treated with this agent (group 2). A subgroup analysis was performed of patients with baseline serum creatinine values above 1.5 mg/dL (group 1A received TMG; group 2A did not). All patients received tacrolimus or cyclosporine (CyA) maintenance immunosuppression.

RESULTS

Indications and demographics were similar between the two groups. Although there was no difference in patient and graft survivals, there was a statistically significant benefit in the rejection-free graft survival at 1 year for group 1 (51% vs 39%; P =.02). Furthermore, serum creatinine at 6 months was lower for group 1, despite a similar baseline creatinine. Subgroup analysis for patients with baseline abnormal serum creatinines showed that group 1A displayed an improved rejection-free graft survival at 1 month but not at 1 year.

CONCLUSIONS

Thymoglobulin induction therapy may allow a delay in the initiation of CI therapy without compromising patient and graft survival, while preventing early rejection, even among patients with baseline renal dysfunction.

A prospective 3-yr evaluation of tacrolimus-based immunosuppressive therapy in immunological high risk renal allograft recipients

BACKGROUND

There have been no published data on use of the the newer immunosuppressants tacrolimus and mycophenolate mofetil (MMF) in high immunological risk renal transplantation. We therefore undertook a prospective study to systematically assess outcomes using these agents as part of an aggressive immunosuppressive regimen.

METHODS

Fifty-nine high-risk renal allograft recipients were enrolled at 10 Canadian sites and given a regimen of: a biological induction agent, tacrolimus, MMF, and corticosteroids. Patients included 10 (17%) who had lost a previous graft to rejection <1 yr, 31 (53%) with a current panel reactive antibody (PRA) >30%, 47 (80%) with a historic PRA >50%, four (7%) who had a positive historical T-cell crossmatch with the current donor, and six (10%) with a current positive B-cell crossmatch. The mean peak PRA was 76 +/- 33%.

RESULTS

The estimated 3-yr Kaplan-Meier patient and graft survival estimates were 89% and 75%, respectively. There were nine graft losses other than deaths with a functioning graft, of which six were preceded by delayed graft function (p = 0.01, chi2). Sixteen (27%) recipients experienced at least one episode of biopsy-confirmed acute rejection. Infections included cytomegalovirus in 16 patients, eight of whom had tissue-invasive disease. Only one malignancy occurred.

CONCLUSIONS

The immunosuppressive strategy investigated is effective and displays a satisfactory safety profile in high immunological risk renal allograft recipients.

Leukoreduction and acute rejection in liver transplantation: An interim analysis

BACKGROUND

Little is known about the effect of blood transfusions and leukoreduction on acute rejection in liver transplantation. The purpose of this study was to assess the impact of leukoreduction on the occurrence of early rejection episodes in liver transplantation.

METHODS

In 1999, mandatory leukoreduction was implemented in our program. Data from 339 consecutive liver transplant recipients were analyzed with attention to the time period as a proxy for leukoreduction, the number of transfusions, the wait list status, the hepatitis B or C status, the recipient age, and the type of immunosuppression.

RESULTS

Using an early (6-month) rejection-free graft survival model, we observed that introduction of leukoreduction was independently associated with fewer rejection episodes (P =.001). Despite the lower rejection rate, due to a regimen of tacrolimus and antithymocyte globulin, the effect of implementation of leukoreduction remained significant (P =.021).

CONCLUSION

The use of leukoreduction is associated with fewer early rejections, irrespective of the type of immunosuppression. These data support an exploration of the immunomodulatory effect of leukoreduction.

Do biliary endoprostheses decrease biliary complications after liver transplantation?

AIM

Most technical complications after orthotopic liver transplantation (OLT) are related to the biliary tree. This report reviews the role of routine intraoperative placement of stents to reduce biliary complications.

METHODS

We retrospectively analyzed 396 consecutive OLTs. We reviewed rates of biliary complications after hepaticojejunostomy (HJA) as well as following choledochocholedochostomy (CCA) groups: "experimental" group (routine intraoperative biliary stenting, last 10 months), "recent" control group (nonstented, previous 10 months), "historical" control group (prior to that period of time).

RESULTS

All groups were matched for donor/recipient characteristics and for graft cold/warm ischemia time. The overall prevalence of biliary complications was 30.7% after CCA versus 35% after HJA. In the experimental group 21 patients had a 4.8% biliary complication rate compared to the recent control and historical groups, where biliary complication rates were 30% and 32.6%, respectively (P <.05).

CONCLUSIONS

The intraoperative use of biliary stents is feasible and appears to decrease the rate of biliary complications. These results support the need for a prospective randomized trial.

Ureteral implantation technique and urologic complications in adult kidney transplantion

AIM

To assess the incidence of urological complications and hematuria after adult kidney transplantation using the Lich-Gregoire (LG) versus the Taguchi (T) ureteral implantation technique.

METHODS

We performed a retrospective analysis of 212 consecutive kidney transplants from our institution using an access database.

RESULTS

Sixty four patients underwent ureteral implantation using the T technique, and the other 148, the LG implantation. Both groups were matched for donor/recipient characteristics and for cold/warm ischemia times. There were 23 urological complications in 17 patients. Twenty-seven patients developed complicated hematuria. The rates of urinary leak and ureteral stones were not different. There was a higher incidence of permanent ureteral strictures using the LG technique (P =.05). T technique was associated more frequently with hematuria, but there was no difference in the length of stay.

CONCLUSIONS

We identified an increased incidence of permanent strictures with the LG technique. The rate of hematuria was higher in the T group. Both techniques can be used interchangeably with acceptable rates of urological complications. The simplicity of the T technique has made it the technique of choice in our institution.

Aberrations in hemostasis and coagulation in untreated discordant hepatic xenotransplantation: studies in the dog-to-pig model

Discordant liver xenotransplantation is a poorly explored entity. Data from the few large animal studies of hepatic xenotransplantation suggest that severe hemorrhage is encountered. The purpose of the studies described here is to characterize the nature of the hemorrhage that accompanies liver xenotransplantation. Canine livers were transplanted into porcine recipients, and lethal hemorrhage was encountered. Analysis of recipient blood showed that factors V, IX, and X were present in adequate levels until after the hemorrhage appeared, suggesting that coagulation factor loss was the result and not the cause of hemorrhage. Platelet counts decreased dramatically in recipients within minutes of graft reperfusion. There also was no evidence of clotting activity in the blood of recipients of liver xenografts within minutes of graft reperfusion. This loss of clotting activity was specific to liver xenografts, was not seen in renal xenografts with or without venovenous bypass, and also was absent in pig-to-pig liver allografts. In brief, the hemorrhage that accompanies liver xenotransplantation occurs because of a decrease in the number and function of circulating platelets in the recipient.

Hepatic sinusoidal endothelium upregulates IL-1alpha, IFN-gamma, and iNOS in response to discordant xenogeneic islets in an in vitro model of xenoislet transplantation

BACKGROUND

Data indicate that early islet graft failure is due to nonspecific inflammatory mechanisms that occur prior to T-cell-mediated rejection. The role of the host hepatic endothelium in mediating this immediate islet injury has not been elucidated. The endothelial cell may be important in this process because it is essentially the first cellular barrier encountered by intraportally introduced islets. We have characterized the initial response of hepatic endothelium to xenogeneic islets by measuring the expression of Il-1alpha, TNF-alpha, IFN-gamma, and iNOS in an in vitro dog-to-pig model of xenoislet transplantation.

MATERIALS AND METHODS

Dog islets (500 islet equivalents) were cocultured with either porcine hepatic endothelium or porcine aortic endothelium over a 24-h period in serum-free medium. RNA was extracted at eight time points (0, 1, 2, 4, 6, 8, 12, and 24 h). Reverse-transcriptase polymerase chain reaction was performed on each sample. Polymerase chain reaction was done on the cDNA in order to visualize Il-1alpha, TNF-alpha, IFN-gamma, and iNOS expression. Bands were semiquantitated by comparison to an external standard (GAPDH) using band densitometry.

RESULTS

Hepatic endothelium had early (1 h) expression of IL-1alpha, IFN-gamma, and iNOS. IL-1alpha peaked at 2 h, IFN-gamma at 12 h, and iNOS at 1 and 12 h. Aortic endothelium expressed low levels of IL-1alpha and TNF-alpha, but not IFN-gamma or iNOS.

CONCLUSIONS

We have demonstrated that xenogeneic islets are able to activate host endothelial cells without serum or immune cells. The observed endothelial response corresponds with known islet toxic substances. Furthermore, the response differs between hepatic and aortic endothelial cells, suggesting that these differences may be important in choosing suitable implantation sites for islets. Our findings suggest that host endothelium may play an important part in early injury of islet xenotransplants.

Pseudoaneurysm of the superior mesenteric artery after pancreas transplantation treated by endovascular stenting

Pseudoaneurysm after pancreas transplantation can have serious consequences, including rupture, hemorrhage, and graft loss. We describe a 38-year-old patient who presented with a pseudoaneurysm of the donor superior mesenteric artery 1 month after pancreas transplantation. Selective arteriography was performed and the lesion was repaired with endovascular placement of a 28-mm covered stent. Laparotomy was avoided. The pancreatic graft was continuing to function well 9 months later. As far as we know, this minimally invasive approach was not previously reported. According to published series, pseudoaneurysms often occur secondary to infection and require operative intervention necessitating graft pancreatectomy. Patients can present with serious symptoms including hypotension and shock. Therefore, it is important to detect pseudoaneurysm in a timely manner. Computed tomography and Doppler ultrasound are important diagnostic tools in this regard. We demonstrated the utility of endovascular stenting in the treatment of pseudoaneurysm after pancreas transplantation. When used in a timely manner in well selected patients, endovascular stenting can abrogate the need for operative intervention and its attendant morbidity.

Successful outcome after transplantation of a donor liver with focal nodular hyperplasia

Because of the increasing gap in the number of patients awaiting organ transplantation and the supply of organ donors, reevaluation of donor criteria is an important issue in clinical transplantation. It has become necessary to make maximal use of the currently available donor pool. We describe a case of successful orthotopic liver transplantation in a 57-year-old man with Laënnec's cirrhosis using a liver containing an 8-cm focal nodular hyperplasia (FNH) lesion involving segments II and III and the caudate lobe. The donor liver was procured from a 46-year-old woman declared brain dead after a subarachnoid hemorrhage. Definitive pathological diagnosis was made at laparotomy by obtaining a Tru-cut (Allegiance Health Care Inc, Toronto, Ontario, Canada) core biopsy specimen. The recipient operation was performed uneventfully except for bleeding from the biopsy site. The patient did well postoperatively and was discharged on tacrolimus, mofetil mycophenolate, and prednisone therapy. He continues to thrive 2(1/2) years posttransplantation with no change in the size of the lesion. In well-selected donors, FNH should not be a contraindication for use in transplantation. However, FNH must be differentiated from hepatocellular adenoma. Although FNH has a benign course with little propensity for bleeding and almost no malignant potential, hepatic adenoma is reported to have a 15% to 33% chance of bleeding and rupture with a well-documented potential for neoplastic degeneration, making the liver unsuitable for donation.

Rejection of pig liver xenografts in patients with liver failure: implications for xenotransplantation

The pathophysiological state of rejection in liver xenotransplantation is poorly understood. Data from clinical pig liver perfusion suggest that pig livers might be rejected less vigorously than pig hearts or kidneys. Pig livers used in clinical xenoperfusions were exposed to blood from patients with liver failure. We have shown in an animal model that transplant recipients with liver failure are less capable of initiating hyperacute rejection of a xenografted liver than a healthy transplant recipient. The goal of this report is to examine the pathological characteristics of pig livers used in 2 clinical pig liver perfusions and combine this information with in vitro studies of pig-to-human liver xenotransplantation to determine whether the findings in the perfused pig livers could be explained in part by the diminished capacity of the patient with liver failure to respond to xenogeneic tissue. Pathological analysis of the perfused pig livers showed immunoglobulin M deposition in the sinusoids with little evidence of complement activation. Our in vitro studies showed that serum from patients with liver failure caused less injury to pig liver endothelium than serum from healthy subjects. Serum from patients with liver failure had similar levels of xenoreactive antibodies as serum from healthy humans. Incubation of serum from patients with liver failure with pig hepatic endothelial cells generated less iC3b, Bb fragment, and C5b-9 than serum from healthy subjects. We conclude that the altered injury in the perfused pig livers can be attributed to the relative complement deficiency that accompanies liver failure.

Comparison of neoral dose monitoring with cyclosporine through levels versus 2-hr postdose levels in stable liver transplant patients

BACKGROUND

We reported that cyclosporine 2-hr postdose levels (C2) correlate better with the AUC0-4 hr than trough levels (C0) in heart transplant patients receiving Neoral.

METHODS

We compared Neoral dose adjustment with C0 (group 1: 100-200 ng/ml) vs. C2 (group 2: 700-1000 ng/ml; group 3: 300-600 ng/ml) in 35 stable adult patients >1 year after liver transplantation. The AUC0-4hr was calculated, and simultaneous blood samples were obtained to measure calcineurin inhibition. Clinical benefit was defined as the absence of rejection and no increase in serum creatinine at the 7-month follow-up.

RESULTS

C2 correlated better with the AUC0-4 hr than C0 (r=0.92 vs. r=0.40). Neoral dose increased by 17% and 39% in groups 1 and 2, and decreased by 18% in group 3 (P=0.002 vs. group 1 and P=0.0004 vs. group 2). Serum creatinine increased by 2.1% and 16% in groups 1 and 2, and decreased by 5.1% in group 3 (P=0.006 vs. group 2). A clinical benefit was observed in 37.5%, 23%, and 82% of patients in groups 1, 2, and 3 (P=0.03 vs. group 1 and P=0.01 vs. group 2). Calcineurin inhibition was similar in all groups at 2-hr (44+/-17%, 39+/-30%, and 44+/-35%), in spite of different Neoral doses (2.9+/-0.9, 4.0+/-1.8, and 2.6+/-1.3 mg/kg/day) and C2 (857+/-226, 922+/-274, and 588+/-274 ng/ml).

CONCLUSIONS

C2 correlated better with the AUC0-4 hr than C0. Neoral dose monitoring with a C2 range of 300-600 ng/ml resulted in a lower dose and greater clinical benefit compared to C0 or a higher C2 in stable liver transplant patients. The correlation between calcineurin inhibition and clinical events deserves further research.

Complement activation in discordant hepatic xenotransplantation

Little is known about hyperacute rejection in hepatic xenotransplantation. Information from clinical xenoperfusions suggests that the liver may be rejected by a mechanism less vigorous than either kidney or heart xenografts. We used the in vitro model of porcine hepatic sinusoidal endothelial cells (PHEC) incubated with either complement replete or deficient human serum to determine the relative roles of the classical and alternate pathways of complement in the immediate response to hepatic xenotransplantation. Our results suggest that either the classical or alternate pathways are capable of independently activating the complement cascade upon exposure to the porcine hepatic sinusoidal endothelium. Our results also imply that either pathway alone is capable of initiating similar degrees of injury as the entire cascade.

Successful treatment of post-transplant lymphoproliferative disorder with interferon-alpha and intravenous immunoglobulin

We report on the use of interferon-alpha (INF-a) and high-dose non-specific intravenous immunoglobulin (IVIg) in 2 patients (a 60-yr-old female and a 65-yr-old male) who developed post-transplant lymphoproliferative disorder (PTLD) 2 and 8 months after heart and liver transplantation, respectively. Both patients had received immunosuppression with ATG, CsA, azathioprine, and prednisone. The first patient did not receive additional immunosuppression with biological agents. The second patient developed 3 steroid-resistant acute rejection episodes requiring OKT3 (cumulative dose 100 mg) and ATG (cumulative dose 3450 mg). The first patient presented with nodules involving the liver, spleen, lungs and nasophar, ynx. The second patient presented with subcutaneous and liver nodules, as well as pert-portal and para-aortic lymphadenopathies. The histological diagnosis was diffuse B-cell PTLD in both patients. Despite reduction of immunosuppression, a progression of lesions was observed in both patients over 5 months and 2 months, respectively. The first patient received INF-alpha (2 x 10(6) IU, s.c. 3 times/wk) and IVIg (0.5 g/kg i.v. every 15 d) for.4 months, while the second patient received the same therapy for 12 and 7 months, respectively. Complete disappearance of all lesions was observed after 3 months of therapy in the first patient and after 7 months of therapy in the second patient, as assessed by CT scan. PTLD remains in remission 47 and 33 months after therapy, respectively. Our preliminary results suggest that the combination of INF-alpha and IVIg can be an effective therapy for PTLD which does not respond to reduction of immunosuppression.

Pulmonary injury in recipients of discordant hepatic and renal xenografts in the dog-to-pig model

Work in our lab demonstrated that the early post-operative course of discordant hepatic and renal xenotransplantation is complicated by a pulmonary injury. The aim of this study was to characterize the nature of this injury, as well as to determine whether endothelin-1 (ET-1) and inducible-nitric oxide synthase (iNOS) are present in this form of pulmonary injury. Dog-to-pig orthotopic liver and kidney xenografts were performed. Pulmonary artery pressures were monitored throughout all procedures. The lungs were stained with monoclonal antibodies for ET-1, endothelin converting enzyme-1, and iNOS. The lungs from pig recipients of hepatic or renal xenografts were compared to lungs from untreated pigs. Pulmonary artery pressures were elevated in recipients of liver xenografts when the suprahepatic caval cross clamp was placed and continued to rise to systolic levels following unclamping. The mean pulmonary artery pressures in recipients of renal and hepatic xenografts rose significantly following revascularization. Pathology in lungs from kidney and liver recipients was similar, showing congestion with peribronchial and septal edema, with diffuse adhesion of PMN to alveolar endothelium. ET-1, endothelin converting enzyme-1 (ECE-1), and iNOS staining was widespread and intense in alveolar and pulmonary arterial endothelium. Discordant xenotransplantation of livers and kidneys is associated with a significant early pulmonary injury that is associated with early PMN infiltration and expression of ET-1 and iNOS.

[A comparative randomized prospective multicenter study of Sandimmune vs Neoral in liver transplantation]

Despite two decades of use, there are limited data on the best way to administer and monitor cyclosporine for orthotopic liver transplantation (OLT). The present study was undertaken: 1) to establish the safety of a new formulation of cyclosporine, Neoral, 2) to determine if treatment with Neoral will improve the results of liver transplantation and 3) to study the relationship between pharmacokinetic parameters and clinical outcomes after OLT. A double-blind, randomized, comparison of Sandimmune and Neoral was conducted at 5 Canadian centers in 188 consecutive adults undergoing OLT. Patients were induced with intravenous cyclosporine (CsA) then switched to Neoral or Sandimmune. Dose adjustments were made daily, or as needed, to reach a target trough CsA level (C0) of 350 ng/mL in both groups. Pharmacokinetic studies were performed on days 5, 10, 15 and 30 after transplantation. The Neoral group stopped intravenous CsA earlier (p < 0.0001), and these patients required a lower median daily oral dose (p < 0.01) to maintain comparable trough CsA levels. Five Sandimmune patients, but no Neoral patients discontinued the study because of the inability to reach target trough levels of CsA within the prescribed time (p < 0.05). At 4 months, there were no differences between the two groups with respect to patient survival, graft survival or rejection-free survival. The incidence of serious adverse events was also similar and did not correlate with CsA profiles. The Neoral group had a higher area under the drug concentration curve (AUC) and peak CsA levels (Cmax). There was a correlation between freedom from graft rejection and both AUC and Cmax at days 5 and 10 post-transplant. In contrast, there was a poor correlation between C0 and graft rejection. In summary, Neoral appears to be safe and well tolerated by patients. Cmax and/or AUC maybe better markers for monitoring cyclosporine based immunosuppression after liver transplantation.

Tacrine does not alter the potency of succinylcholine in the rat

PURPOSE

Tacrine is a cholinesterase inhibitor used to manage Alzheimer's dementia. Given iv, it prolongs succinylcholine blockade in humans but the effects of chronic oral tacrine are not known.

METHODS

Groups of adult rats were given 2.5 mg.kg-1 tacrine (chronic groups) or l ml saline (control) twice daily by gavage for one, two, four or eight weeks. An additional (acute) group received 2.5 mg.kg-1 tacrine iv. Twelve to 18 hr after the last gavage of tacrine or saline, and -20 min after iv tacrine, cumulative dose-response curves of succinylcholine were determined in the tibialis and soleus muscles in anaesthetized, ventilated rats during monitoring of evoked twitch response to indirect (nerve) train-of-four stimulation.

RESULTS

The ED50 and ED95 of succinylcholine in control rats were (mean +/- SD) 204 +/- 41 and 382 +/- 96 micrograms.kg-1, respectively in the tibialis muscle, and 280 +/- 52 and 629 +/- 168 micrograms.kg-1 in the soleus muscle (P < 0.05 between muscles). In the acute and chronic tacrine groups, the mean ED50 and ED95 ranged from 166-197 and 277-396 micrograms.kg-1., respectively, in the tibialis muscle, and 248-333 and 546-667 micrograms.kg-1, in the soleus muscle. Dose responses did not differ among acute and chronic tacrine groups and the control group.

CONCLUSION

Chronic oral tacrine does not alter muscle response to succinylcholine in the rat. This may not apply to Alzheimer patients receiving chronic tacrine since the interaction between acute tacrine and succinylcholine in the rat differs from that in humans.

Recurrence-free long-term survival after liver transplantation for hepatitis B using interferon-alpha pretransplant and hepatitis B immune globulin posttransplant

OBJECTIVE

The authors determined whether pretransplant reduction of hepatitis B virus (HBV) load using alpha-interferon-2b (IFN) and passive immunoprophylaxis using hepatitis B immunoglobulin (HBIg) posttransplantation can prevent HBV recurrence in patients undergoing liver transplantation (LT) for HBV cirrhosis.

SUMMARY BACKGROUND DATA

Liver transplantation in patients with HBV cirrhosis is associated with a high rate of recurrence and reduced survival. In patients with evidence of replicating virus (HBV-DNA or hepatitis B e antigen [HBeAg]-positive serum or both), recurrence is nearly universal. Passive immunoprophylaxis with HBIg alone is not effective in preventing HBV recurrence posttransplant, especially in patients with evidence of active viral replication pretransplant. Higher doses of HBIg posttransplant has reduced recurrence rates to 30% to 50%. Lamivudine, a nucleoside analogue that has shown early promise, also is associated with significant HBV recurrence. The authors report a reliable method of preventing viral recurrence in patients even with evidence for active HBV replication pretransplant.

METHODS

Pretransplant patients with evidence of replicating HBV were given IFN starting at 1 million IU 3 times per week subcutaneously. This dose was increased to 2 and then 3 million IU 3 times per week when patient's side effects permitted and was maintained until the patient underwent a LT. All patients were tested every 4 weeks for hepatitis B surface antigen (HBsAg), HBeAg, and HBV-DNA. When patients became negative for HBeAg and HBV-DNA, they were listed for LT. Patients that were only HBsAg positive were listed immediately and received a LT without prior IFN treatment. Post-LT, all patients began receiving HBIg 2000 IU (10 mL) daily from days 1 to 20 and then weekly for the first 2 years. After 2 years, all patients received 2000 IU (10 mL) monthly. Additional HBIg immunoprophylaxis was given during intense immunosuppression for rejection. Posttransplant serum was tested for HBsAg, HBeAg, and HBV-DNA in all patients 1 week, 1 month, and every 3 months thereafter. Liver biopsies were done at least yearly and when liver enzymes were abnormal and were always tested for HBsAg and HBcAg by immunoperoxidase.

RESULTS

Thirteen patients with decompensated HBV cirrhosis were transplanted. Pretransplant, eight patients had evidence of active viral replication at the initial assessment (HBeAg or HBV-DNA-positive serum or both). All eight were successfully treated with IFN (median duration, 24 weeks; range, 8-53) and converted to a negative status before transplantation. Side effects from IFN were minimal and well tolerated, except in one patient who required 6 million IU to convert to a nonreplicating status. The five patients that were only HBsAg positive were not treated with IFN pretransplant. After surgery, HBIg given as described achieved consistently serum levels greater than 1000 IU/L. Twelve of the 13 patients are alive with normal liver function and without serologic evidence of HBV recurrence at a median follow-up of 32 months (range, 9-56 months). None have evidence of HBV recurrence as measured by serum HBsAg/HBeAg/HBV-DNA at recent follow-up. The sera of the seven longest survivors has tested negative for HBV-DNA using the polymerase chain reaction method. In addition, a liver biopsy was obtained in six of these patients, the results of which also tested negative for HBV-DNA using polymerase chain reaction. Liver biopsy specimens have been negative for the presence of HBsAg and HBcAg by immunoperoxidase staining in all 12 patients.

CONCLUSION

A reduction of viral load pretransplant with IFN and posttransplant HBIg prevents recurrence of hepatitis B and permits LT for HBV cirrhosis, even in patients with evidence of replicating virus. The IFN pretransplant was well tolerated, and the small frequent dosing of HBIg posttransplant did not cause side effects while achieving serum levels > 1000 IU/L.

The effects of chronic tacrine therapy on d-tubocurarine blockade in the soleus and tibialis muscles of the rat

Tacrine (THA) is an anticholinesterase drug used to manage Alzheimer's dementia, but it is not clear how its chronic use might affect response to nondepolarizing muscle relaxants. We determined the magnitude and time course of the effects of chronic oral THA and of intravenous (IV) THA on d-tubocurarine (dTC) blockade at the soleus and tibialis muscles. Six groups of adult rats were given 10 mg/kg THA twice daily by gavage for 1, 2, 4, or 8 wk (chronic THA groups), or 1 mL of saline twice daily by gavage for 1-8 wk (control), or IV THA approximately 20 min before (acute), and the cumulative dose-response curves of dTC at the tibialis and soleus muscles were determined during indirect train-of-four stimulation in the anesthetized, mechanically ventilated rat. The 50% effective dose (ED50) and 95% effective dose (ED95) of dTC in control rats were (mean +/- SD) 30 +/- 10 and 61 +/- 18 microg/kg in the tibialis and 32 +/- 8 and 75 +/- 19 microg/kg in the soleus; respectively. IV THA increased the ED95 of dTC 2.5- to 3-fold (P < 0.05) but did not alter the ED50. Chronic THA increased both the ED50 and ED95 of dTC 1.5- to 2-fold (P > or = 0.05), and this effect tended to decrease with duration of THA therapy. We conclude that chronic THA therapy in rats causes resistance to dTC, with a tendency for the resistance to decrease with time, probably because of down-regulation of postsynaptic acetylcholine receptors. The same may apply to Alzheimer's patients taking THA chronically.

Indefinite allograft survival induced by the combination of multiple donor-specific transfusions, cyclosporine, and an anti-T cell monoclonal antibody in a protocol relevant to cadaveric organ transplantation. The importance of prolonged posttransplant cyclosporine coverage

A single donor specific transfusion (DST) 24 hr pretransplant and Cyclosporine (CsA) are synergistic in inducing prolongation of allograft survival. This synergy was further potentiated by giving 3 additional DSTs at weekly intervals posttransplant, or by the additional administration of a small dose of the anti-T cell monoclonal antibody OX-52 24 hr pretransplant to the above protocol. This study determined whether indefinite survival can be achieved in the ACI-to-Lewis heart allograft model by combining an anti-T cell monoclonal antibody, 4 DSTs given once 24 hr pretransplant and weekly 3 times posttransplant, and CsA. CsA was given daily for 28 days or 60 days posttransplant. The dose consisted of CsA 5 mg/kg/day starting 24 hr pretransplant and continuing until day 7 posttransplant and followed by 2.5 mg/kg/day for either 21 more days (total CsA days = 28 days) or 53 days (total CsA days = 60 days). The anti-T cell monoclonal antibody OX52 (200 micrograms i.v.) was given once 24 hr pretransplant. DST (1 ml) was given 24 hr pretransplant and on days 7, 14, and 21 posttransplant. Low-dose CsA for 28 days never induced indefinite allograft survival. CsA for 60 days, however, resulted in the occasional indefinite allograft survival (> 1 year) even in this difficult model. The addition of DST 24 hr pre- and posttransplant on days 7, 14, and 21 to both 28 days and 60 days of CsA further prolonged allograft survival. The best survival was seen in the group given DST 24 hr pre- and on days 7, 14, and 21 posttransplant and 60 days of CsA, with all the allografts surviving beyond 100 days of CsA, with all the allografts surviving beyond 100 days and more than 50% surviving indefinitely (> 1 year). The addition of a single dose of OX52 24 hr pretransplant to the multiple DSTs and 28 days of CsA protocol significantly improved indefinite allograft survival but its influence was less dramatic when given to the multiple DSTs and 60 days of CsA protocol. This beneficial interaction between CsA, DST, and an anti-T cell MoAb offers a clinically applicable protocol for both living donor and cadaveric organ transplantation in inducing donor-specific hyporesponsiveness, and further investigations are warranted.

Small bowel transplantation. The effect of intraportal donor-specific transfusion 24 hours pretransplant and low-dose cyclosporine

We tested the synergy of donor-specific transfusion (DST) and cyclosporine (CsA) in small bowel transplantation by comparing the systemic versus portal route of DST administration in a fully allogeneic rat model. The protocol is relevant to cadaveric transplantation by conditioning only 24 hr before allografting. A 1 ml intraportal DST day -1 and low-dose CsA significantly prolonged survival (MST 53.7 +/- 17.5 days) when compared with systemic DST day -1 and low-dose CsA (MST 18.4 +/- 5.6 days). This suggests that intraportal DST can be beneficial in cadaveric SBT, as only a 24-hr induction period is necessary. We speculate that antigen trapping in the liver and interaction of the DST with Kupffer cells is central to the portal DST effect.

Bacterial translocation: a potential source for infection in acute pancreatitis

Infections from enteric bacteria are a major cause of morbidity and mortality during acute pancreatitis (AP), but the pathways by which these organisms reach distant organs remains speculative. Experiments were conducted to determine if bacterial translocation could be a mechanism for infection during this disease. AP was induced in Lewis rats by i.v. infusion of caerulein (experiment I) or ligation of the head of the pancreas (experiment II). In a third experiment, rats were gavaged with 1 x 10(8) 14C-radiolabeled Escherichia coli and pancreatitis was induced with caerulein. Results in all three experiments showed that AP increased the number of viable bacteria recovered in peritoneal fluid, mesenteric lymph nodes (MLN), liver, lungs, and pancreas. Radionuclide counting indicated that AP enhanced the gut permeability to 14C E. coli. To estimate the impact of AP on the magnitude of translocation and on the ability of the host to clear bacteria, the nuclide and colony-forming units (CFU) ratios were calculated between animals with and without AP. Blood, peritoneal fluid, and MLN had the highest nuclide ratio. During AP, these tissues may be the principal routes for bacterial spreading from the gut lumen. Peritoneal fluid, pancreas, and lung were the tissues with the highest CFU ratio. Bacterial killing ability of these tissues is likely impaired during AP.

Effects of pre- and postengraftment donor-specific transfusions and cyclosporine on the enhancement of experimental allograft survival

The tolerogenic effects of immediate pretransplant donor-specific transfusion (DST) with cyclosporine (CsA) have been well described. The purpose of this study was to determine if these effects could be improved upon by the administration of post-transplant DSTs. When added to a 29-day course of CsA, a single DST given 24 hr pretransplant improved graft survival compared to CsA alone (84.9 +/- 12.3 vs 40.0 +/- 8.8 days; P less than 0.05). The administration of an additional DST on post-transplant Days 7, 14, and 21 further improved this survival to 152 +/- 28 days, with 45% of grafts surviving greater than 200 days, until sacrifice. The donor specificity of this effect was demonstrated by the increased survival of second ACI grafts transplanted into Lewis recipients with existing "tolerant" ACI allografts (long-term survivors, or LTS); third-party Buffalo rat hearts transplanted into LTS rats in a similar manner were rejected normally. Loss of graft antigenicity was not seen, as retransplanted ACI hearts obtained from LTS Lewis rats were rejected in a first-order manner. From this we conclude that (1) the addition of multiple post-transplant DSTs improve the enhancement seen with preoperative DST and CsA, (2) loss of graft antigenicity does not contribute to this improved enhancement, and (3) this effect appears to be donor antigen specific.

Enhancement of allograft survival by donor-specific transfusion one day prior to transplant. Importance of timing and specificity when DST is given with cyclosporine

Donor-specific transfusion effects were studied in the ACI-to-Lewis rat heterotopic heart allograft model using cyclosporine immunosuppression. Low-dose CsA for 1 week plus a single fresh or stored DST given 1 day before allografting significantly prolonged graft survival over CsA therapy alone (median survival time 23.5 days vs. 10 days, P less than 0.01), but third-party transfusion did not (11.5 vs. 10 days, NS). When CsA was started at the time of DST and continued for 2 weeks, maximal graft enhancement was achieved after just one DST. DST/CsA was equally efficacious if given on any day before transplantation, provided CsA was started on the same day as the transfusion. However, pretransplant DST given without CsA shortened subsequent graft survival of day -1 DST/CsA treatment (14.5 days, n = 6, vs. 60 days for controls, n = 10; P less than 0.01). The addition of methylprednisolone to the DST/CsA protocol had no effect on graft survival (51 vs. 53 days, P = NS), but extending the period of postoperative CsA therapy for 4 weeks at reduced dose (2.5 mg/kg/day) significantly prolonged median survival (111 days, n = 11) and resulted in 45% permanent engraftment (greater than 120 days survival). CsA permits graft enhancement with a single DST as early as 1 day before grafting. This avoids the risk of sensitization from DSTs and can extend DST use to cadaveric graft recipients.

Disseminated histoplasmosis in a renal transplant patient: a cause of renal failure several years following transplantation

A 49-year-old man developed disseminated histoplasmosis 6 1/2 years after transplantation. The organism was initially present in the urine and in a tongue lesion. Treatment with itraconazole was instituted. However, there was further dissemination of the disease and worsening of renal function. Allograft biopsy showed extensive involvement with the organism. Amphotericin B was started, resulting in a rapid resolution of the disease. However, renal function deteriorated, leading to permanent hemodialysis.

Segmental orthotopic hepatic transplantation as a means to improve patient survival and diminish waiting-list mortality

Pediatric liver transplantation continues to be limited by the availability of suitable liver donors, a factor that restricts programmatic development and ultimately contributes to death on the recipient waiting list. We report the application of segmental liver transplantation as a technique to address both these problems as well as improving the outcome of the child undergoing the transplant procedure. Since 1986, 37 children have undergone orthotopic liver transplantation. Twenty-three children have received whole-organ grafts; 81% survived. Of those receiving whole-organ grafts, 15% had arterial thrombotic complications and 23% required retransplantation. More importantly, 29% of those children listed for transplantation died while waiting for a donor organ to become available, with a mean interval of 1.7 months (range, 2 days to 4.5 months). Since July 1988, segmental liver transplantation has been a component of our therapeutic armamentarium, and of the past 20 liver recipients, 16 have received a left lobe segmental graft. The results of the segmental transplant series have shown striking improvements. First, no child has died while awaiting donor organ availability. Second, segmental liver recipient survival is equivalent to that of whole-organ graft recipients (81%). Third, hepatic arterial thrombosis, especially a problem in high-risk infant transplants, was reduced by this technique (5%). Retransplantation due to graft complications has not increased (21%). These data suggest a vital role for segmental liver transplantation not only as a remedial salvage procedure for the critically ill child, but also as a primary transplant option.

Increased gut permeability following burn trauma

Twenty female Hartley guinea pigs, weighing 350 to 400 g, were given a 30% full-thickness burn injury. Gastrointestinal permeability was assessed before burn and on postburn days 1 through 3, 7, and 14 by administering 5 mL of an isotonic mixture of 8% lactulose and 1.15% L-rhamnose by gavage and measuring the urinary excretion for the next 7 hours. In normal guinea pigs, lactulose (molecular weight, 342d) is mostly absorbed by the paracellular route, whereas L-rhamnose (molecular weight, 164 d) is mostly absorbed by the transcellular route. Gut permeability to L-rhamnose did not increase after burn injury (211 micrograms before burn vs 230, 260, 180, 238, and 221 micrograms on days 1, 2, 3, 7, and 14, respectively, after burn). By contrast, gut permeability to lactulose increased significantly and was greatest in the first 48 hours after burn injury (60 micrograms before burn vs 380, 354, 203, 364, and 279 micrograms on days 1, 2, 3, 7, and 14, respectively, after burn). Gut permeability to low-molecular-weight compounds increases immediately after burn trauma, and this may be by a paracellular rather than transcellular mechanism.

Selection criteria for liver transplant donors

As the number of successful liver transplants has increased, the demand for donors has outpaced the supply. Approximately 25% of patients die awaiting an appropriate donor. Current criteria for assessing potential donors need to be closely examined. Fifty-six potential donors were evaluated by our transplant team by utilizing standard liver function tests (LFT's)-SGOT, SGPT, bilirubin. Additionally, a lidocaine metabolism test was performed by giving a 1 mg/kg IV dose of lidocaine over 1 minute and measuring the accumulation of the major metabolite monoethylglycinxylidide (MEGX) at 15 minutes by fluorescent polarization immunoassay (Abbott Diagnostics, Abbott Park, IL). Previous work has suggested that a MEGX less than 50 ng/mL is associated with initial non-function. Thirty-four donors were transplanted (group I) and all had initial function (all MEGX values were greater than 50). Twenty-two donors (39%) were judged unacceptable (group II) by our transplant team and by outside centers based upon one of the following criteria: II A) elevated LFT's--8, 11 B) donor age--5, II C) donor instability--4, II D) no available recipient--3, II E) miscellaneous--2. Standard LFT's were not statistically different in the donors used and in those not used when excluding category II A. Six of seven donors excluded in group I had acceptable MEGX values indicating they may have been transplantable. Ten of 12 patients excluded in groups II B-D had normal LFT's and nine of 12 had acceptable MEGX values indicating they may have been transplantable also. In this era of organ shortage, a reevaluation of donor selection criteria utilizing new tests like MEGX may be necessary to meet the increased need.

The use of the hypogastric artery in the anastomosis of multiple renal arteries in the transplant patient

Alternative techniques for handling multiple renal vessels in living related kidney transplants by use of the hypogastric artery are presented. This vessel can be used either as a tubular vascular graft or as a Carrel patch graft. Details of these techniques are discussed.