Arterial flow regulator enables transplantation and growth of human fetal kidneys in rats.

Here we introduce a novel method of transplanting human fetal kidneys into adult rats. To overcome the technical challenges of fetal-to-adult organ transplantation, we devised an arterial flow regulator (AFR), consisting of a volume adjustable saline-filled cuff, which enables low-pressure human fetal kidneys to be transplanted into high-pressure adult rat hosts. By incrementally withdrawing saline from the AFR over time, blood flow entering the human fetal kidney was gradually increased until full blood flow was restored 30 days after transplantation. Human fetal kidneys were shown to dramatically increase in size and function. Moreover, rats which had all native renal mass removed 30 days after successful transplantation of the human fetal kidney were shown to have a mean survival time of 122 days compared to 3 days for control rats that underwent bilateral nephrectomy without a prior human fetal kidney transplant. These in vivo human fetal kidney models may serve as powerful platforms for drug testing and discovery.

Artificial liver support devices for fulminant liver failure.

Artificial liver-support devices attempt to bridge patients with fulminant hepatic failure until either a suitable liver allograft is obtained for transplantation or the patient's own liver regenerates sufficiently to resume normal function. It is thought that toxins contribute to the clinical picture of fulminant hepatic failure. The earliest reports of successful toxin removal were blood- and plasma-exchange transfusions. Given these successful case reports, mechanical liver-support devices were designed to filter toxins. These mechanical devices used hemodialysis, charcoal hemoperfusion, hemoperfusion through cation-exchange resins, hemodiabsorption, and combinations of all of these techniques as in the MARS liver-support device. Despite promising case reports and small series, no controlled studies of mechanical devices have ever showed a long-term survival benefit. Thus, the removal of presumed toxins seems to be insufficient to support patients with fulminant hepatic failure, and the biologic function of the liver must also be replaced. Attempts at replacing the biologic function have included extracorporeal liver perfusion, cross-circulation, and hepatocyte transplantation. Current technologies have combined mechanical and biologic support systems in hybrid liver-support devices. The mechanical component of these hybrid devices serves both to remove toxins and to create a barrier between the patient's serum and the biologic component of the liver-support device. The biologic component of these hybrid liver support devices may consist of liver slices, granulated liver, or hepatocytes from low-grade tumor cells or porcine hepatocytes. These biologic components are housed within bioreactors. Currently the most clinically studied bioreactors are those that use capillary hollow-fiber systems. Both the bioartificial liver by Demetrious and the extracorporeal liver-assist device by Sussman and Kelly are in clinical trials. Although the trials seemed to have yielded good survival data when the devices are used as a bridge to transplantation, the type and degree of liver support provided by these devices remains uncertain. Thus, despite decades of great progress in the field of artificial liver support, no one technique alone yet provides sufficient liver support. A hybrid system seems to be the best option at present. Still to be determined is the best tissue to use, how much liver tissue should be used, and the optimal design of the bioreactor.

Posttransplantation lymphoproliferative disorders in pediatric patients undergoing liver transplantation.

OBJECTIVES: To study the clinicopathologic and molecular genetic findings in posttransplantation lymphoproliferative disorders (PTLDs) following pediatric liver transplantation and to determine the applicability of a recently proposed consensus classification system. DESIGN: The clinical, pathologic, and molecular genetic findings of 11 PTLDs that occurred in 10 patients are presented. These 10 patients were derived from a group of 121 pediatric patients who underwent liver transplantation at the University of California, San Francisco. The PTLDs were classified using the proposed Society for Hematopathology scheme. Clonality was determined by immunohistochemical detection of monotypic immunoglobulin or by using polymerase chain reaction-based methods to detect monoclonal immunoglobulin heavy-chain gene rearrangements. Epstein-Barr virus (EBV) was detected by immunohistochemistry, in situ hybridization, or polymerase chain reaction. Epstein-Barr virus typing and the presence of LMP1 gene deletions were also analyzed by polymerase chain reaction. RESULTS: There were 3 early lesions, 4 polymorphic PTLDs, and 4 monomorphic PTLDs. Monoclonality was demonstrated in 8 of 9 cases assessed. Epstein-Barr virus was present in all cases; of 9 cases assessed by polymerase chain reaction, the virus was type A in 8 and type B in 1. No EBV LMP1 gene deletions were identified. The corresponding liver explants were negative for EBV in 8 cases and positive in 1 case. Greater than 3 foci of disease and monomorphic PTLD were associated with decreased actuarial survival (P <.05). CONCLUSIONS: The prognosis of pediatric patients with PTLD is favorable for early lesions and polymorphous PTLD, particularly in patients with localized disease. Multifocal disease and monomorphic PTLD are associated with an unfavorable prognosis.

Donor origin of neuroendocrine carcinoma in 2 transplant patients determined by molecular cytogenetics.

Organ transplant recipients have an increased tumor incidence owing to their immunocompromised state. The origin of such tumors, whether donor or recipient, will have a clinical impact on decision-making concerning immunosuppressive therapy, retransplantation, and for recipients of other organs from the same donors. We report molecular cytogenetic determination of donor origin in 2 cases of small-cell neuroendocrine carcinoma developing in sex-mismatched transplant recipients (kidney and liver). Fluorescence in situ hybridization (FISH) analysis was performed on liver core needle biopsy material from the liver transplant patient and on liver fine needle aspiration cytopreparations from the kidney transplant patient. The results for the liver transplant patient were confirmed with microsatellite allelic analysis and with comparative genomic hybridization. In both cases, FISH showed the presence of only X chromosomes within the tumor cells, indicating the donor origin of the neoplasms. FISH is an excellent method to determine neoplastic origin in sex-mismatched transplant patients. HUM PATHOL 31:1425-1429.

Flow cytometry crossmatching as a predictor of acute rejection in sensitized recipients of cadaveric renal transplants.

Flow cytometry crossmatching (FCXM) was developed as a more sensitive assay than the standard complement-dependent cytotoxicity crossmatch (CDCXM) for the detection of anti-donor antibodies, that mediate hyperacute rejection and graft loss in the early post-transplant period in renal transplant recipients. The role of FCXM in predicting long-term clinical outcome in renal allograft recipients is unclear. This study examines the role of FCXM in predicting long-term clinical outcome in highly sensitized recipients of cadaveric renal transplants. All patients (n = 100) with peak panel reactive antibody (PRA) levels > 30%, who received cadaveric renal transplants between 1/1/'90 and 12/31/'95 at our institution, were divided into FCXM + and FCXM - groups. The incidence of acute rejection was determined for each group during the first yr after transplant. Graft survival rates at 1, 2, and 3 yr, and creatinine levels were also compared between groups. FCXM + patients experienced a higher incidence of acute rejection during the first yr after transplant (69 vs. 45%), and a higher percentage of FCXM + patients had more than one episode of acute rejection during the first yr after transplant (34 vs. 8%) when compared to FCXM - patients. There was no statistically significant difference in 1-, 2-, or 3-yr graft survival between FCXM + and FCXM - patients (76 vs. 83, 62 vs. 80, 62 vs. 72%, respectively). These results suggest that sensitized FCXM + cadaveric renal transplant recipients have a higher incidence of acute rejection episodes in the first yr after transplant. Given the association of multiple rejection episodes with poor long-term allograft survival, FCXM may be a useful predictor of long-term clinical outcome in this sub-group of renal transplant recipients.

Experience with daclizumab in liver transplantation: renal transplant dosing without calcineurin inhibitors is insufficient to prevent acute rejection in liver transplantation.

BACKGROUND: Daclizumab is a monoclonal antibody directed against the alpha chain of the interleukin 2 receptor. We review our experience with the use of daclizumab in liver transplant recipients. METHODS: Thirty-two patients were given daclizumab as induction therapy in the setting of hepatic transplantation. Seven of these patients were enrolled in a pilot study to determine the efficacy of daclizumab in conjunction with corticosteroids and mycophenolate mofetil without the initial use of calcineurin inhibitors (CI). The remaining 25 patients received daclizumab, mycophenolate mofetil, and steroids, with the institution of CI generally within the first postoperative week. The majority of these patients (n = 17) had some degree of renal insufficiency. RESULTS: The pilot study was halted after the first seven patients were enrolled because of an unacceptably high rate of rejection (7/7 = 100%). The patients outside of this pilot study, however, had a much lower rate of rejection (36%). The incidence and severity of rejection correlated with the delay in institution of CI. The described dosing schedule resulted in subtherapeutic daclizumab levels in liver transplant recipients. CONCLUSIONS: Daclizumab used in liver transplant recipients without any CI was ineffective and can potentially lead to steroid-resistant rejection. The dosing regimen used in renal transplant recipients is most likely insufficient for liver transplant patients. However, daclizumab can be used safely in patients with preexisting or postoperative renal dysfunction in conjunction with low doses of CI given within the first week postoperatively.

Intramuscular hepatitis B immune globulin combined with lamivudine for prophylaxis against hepatitis B recurrence after liver transplantation.

Immunoprophylaxis using intravenous (IV) hepatitis B immune globulin (HBIG) decreases the recurrence of hepatitis B virus (HBV) infection after orthotopic liver transplantation (OLT). However, IV HBIG is expensive, has significant side effects, and is inconvenient to administer. An alternative approach for prophylaxis using intramuscular (IM) HBIG and oral lamivudine was prospectively evaluated in this study. Ten consecutive patients with cirrhosis with HBV infection who underwent OLT were included in this study. Nine of 10 patients received lamivudine, 150 mg/d, for an average duration of 8.6 months before OLT. Two of 10 patients with detectable HBV DNA at the time of OLT received 10,000 U (45 mL) of IV HBIG daily for 7 consecutive days, followed by 5 mL of IM HBIG weekly for the next 3 weeks, then every 3 weeks. The other 8 patients were HBV DNA negative at OLT and received one dose of IV HBIG (45 mL) during surgery, followed by 5 mL of IM HBIG weekly for 4 weeks, then every 3 weeks. All patients received lamivudine, 150 mg/d, after OLT. During a mean follow-up of 15.6 months, 9 of 10 patients achieved a protective hepatitis B surface antibody (HBsAb) titer greater than 200 IU/L and had no evidence of HBV recurrence. One patient failed to develop an adequate HBsAb titer and developed histological and virological evidence of recurrence. One patient died unrelated to HBV recurrence. Our preliminary data suggest that this combination prophylaxis with IM HBIG and lamivudine is effective and potentially cost saving.

Hepatic artery pseudoaneurysm with hemobilia following angioplasty after liver transplantation.

A 58-yr-old female with primary biliary cirrhosis underwent an uncomplicated orthotopic liver transplantation. Elevated liver function tests 2 months post-transplantation were evaluated with Doppler ultrasound and a hepatic artery stricture was documented. The hepatic artery stenosis was treated with angioplasty. She developed hemobilia 1 d after the procedure, which was confirmed by angiography. Emergent exploratory laparotomy revealed a pseudoaneurysm at the hepatic artery anastomosis. The pseudoaneurysm was resected and the proper hepatic artery of the graft was anastomosed to the splenic artery of the host using preserved homograft. Her post-operative course was uneventful and liver function tests returned to normal quickly after the surgery. This report will discuss the unusual nature of this complication, and review the problem of hemobilia and pseudoaneurysms in liver transplant recipients.

Ureteral obstructions and leaks after renal transplantation: outcome of percutaneous antegrade ureteral stent placement in 44 patients.

PURPOSE: To analyze the outcome of percutaneous antegrade ureteral stent placement for treatment of ureteral stenoses and leaks after renal transplantation. MATERIALS AND METHODS: Antegrade pyelography and percutaneous ureteral stent placement were performed in 45 patients with ureteral obstruction (n = 40), leak (n = 3), or both (n = 2). Obstructions were graded as mild, moderate, or complete, and as early (< or = 3 months after transplantation) or late (> 3 months). RESULTS: The outcome of stent placement was successful in 25 (57%) patients (average follow-up, 30 months). The ureteroneocystostomy (UNC) was the most common site of obstructions (22 of 41), leaks (four of five), and successful outcomes (16 of 22). Moderate obstructions were most common (29 of 41) and responded best to treatment (17 of 29). Eighteen (69%) of 26 early obstructions and five (33%) of 15 late obstructions were successfully managed percutaneously. All complications (12 of 45 patients) were minor, with infections the most common (n = 7). No mortality or allograft loss was attributable to stent placement. CONCLUSION: Ureteral stents are safe and effective for the treatment of obstructions and leaks and are particularly effective for early and UNC obstructions. These stents may also be useful for temporary drainage.

Posttransplant lymphoproliferative disorder presenting in the head and neck.

OBJECTIVE: To determine the incidence of focal head and neck posttransplant lymphoproliferative disorder (PTLD) in children, its clinical presentation, associated risk factors, and outcome following treatment. STUDY DESIGN: Retrospective. METHODS: The authors conducted a 5-year retrospective study of 61 children with liver transplants at the University of California, San Francisco. Suspected head and neck lesions were evaluated and biopsies were performed by an otolaryngologist. Diagnosis was made via histologic and immunohistochemical features and in situ Epstein-Barr virus (EBV) localization. RESULTS: Eight patients (13.1%) developed PTLD, five (8.2%) in the head and neck. Four patients had large tonsils, and one presented with airway obstruction from a supraglottic mass. Negative pretransplant EBV serology was a risk factor for PTLD. Treatment consisted of antiviral therapy and decreased immunosuppression. All patients with head and neck PTLD are disease free with excellent liver function. CONCLUSIONS: A high incidence of PTLD was found, with 63% presenting in the head and neck. While Waldeyer's ring is most commonly involved, PTLD may also present in the supraglottis. Adjunctive antiviral therapy and decreased immunosuppression are effective forms of treatment. Given the increasing number of pediatric liver transplants being performed, otolaryngologists should be familiar with PTLD and have a high index of suspicion in this at-risk population.

Immunologic and patient selection strategies for successful utilization of less than 15 kg pediatric donor kidneys--long term experiences with 40 transplants.

Renal transplantation using infant donors is associated with significantly less graft survival (GS) and increased morbidity, especially from very young and small donors. We report our results using specific strategies to determine which age and size donor require en bloc renal transplant reconstruction and associated immunologic protocols for optimization of subsequent GS. Forty cadaveric pediatric en bloc renal transplants were performed. Mean donor age was 23.6+/-18.4 months with subgroups: 2-12 months, n=14; 13-24 months, n=19; and 25-60 months, n=7. Mean donor weight was 14.4+/-4.5 kg. All kidneys were placed in primary, nonsensitized (peak PRA = 7.9+/-5.6%) adult (41.6+/-16 years) recipients. Low weight was preferred (62.4+/-12.8 kg). Mean cold ischemia time was 26.9+/-8.6 hr. Immunosuppression consisted of quadruple immunosuppression (QI) with OKT3 induction. All patients had ureteral stents placed intraoperatively. Mean follow-up was 16.9 months. Actuarial GS at 12, 24, and 33 months were 100% (n=13), 85% (n=20), and 71% (n=7), respectively. Total GS was 35/40=88%. All grafts functioned immediately and there were no technical losses. Biopsy proven rejections occurred in 12 (30%) patients, developing at 16-167 days postoperatively (mean = 50.3 days). Mean serum creatinine at one week and 1, 6, 12, and 18 months were 2.1+/-2.0, 1.5+/-0.8, 1.3+/-0.5, 1.1+/-0.4, and 0.9+/-0.4 mg/dl, respectively. Functional isotopic renography, as well as sonographic monitoring reflected rapid initial and continued growth in these kidneys. Mean BP at 12 and 24 months postoperatively were 145/83+/-18/13 and 122/76+/-20/10 mmHg, respectively, with no significant proteinuria noted. Excellent results with minimal complications utilizing very small and young infant donors can be achieved with QI immunosuppression, and selection of low immune reactive and noncomplicated adult recipients. Additionally, maximal renal dosing by minimizing recipient weight may prevent future hyperfiltration damage.

Increased efficacy of CSA following rearterialization in the rat OLTX model.

Many investigators presently use a rat orthotopic liver transplant (OLTX) model without rearterialization of the graft. Rearterialization has been demonstrated to have a variable effect on the rejection response in various strain combinations. However, there are little data on the effects in a model with immunosuppression. The influence of rearterialization on the efficacy of cyclosporine (CSA) in such a model was examined, with the hypothesis that rearterialization may alter the rejection response and efficacy of cyclosporine. OLTX was performed between adult male D Agouti rats and Lewis rats. Rearterialization was performed between the recipient and donor celiac axis, and CSA was delivered at 1 mg/kg/day by continuous infusion for 14 days postoperatively. Treatment groups consisted of no rearterialization/no CSA, rearterialization/no CSA, no rearterialization/CSA, and rearterialization/CSA. Survival time and histology of liver grafts were measured. Rearterialization itself did not prolong survival in this strain combination (median survival no rearterialization/no CSA is 11 days versus median survival rearterialization/no CSA is 10 days). The addition of CSA at this dose without rearterialization also did not prolong survival (median survival no rearterialization/CSA is 15.5 days). The combination of CSA with rearterialization did prolong survival significantly (median survival rearterialization/CSA is 22 days; P < 0.05 versus the other three groups). The mechanism of this increased efficacy is unknown, but may involve altered MHC antigen expression, altered metabolism of CSA, decreased toxicity of CSA, or decreased nonspecific inflammation in the rearterialized grafts.

Predicting recidivism after orthotopic liver transplantation for alcoholic liver disease.

With appropriate selection criteria, patients with end-stage alcoholic liver disease who undergo orthotopic liver transplantation have similar graft and patient survivals as patients undergoing transplantation for other causes. However, because of the possibility of recidivism after orthotopic liver transplantation there is still reluctance to transplant alcoholic patients. This study examined the association between pretransplant psychosocial variables and the risk of recidivism after orthotopic liver transplantation. At our institution, 43 patients received orthotopic liver transplantation for the referral diagnosis of alcoholic liver disease from February 1, 1988 to May 1, 1991. This represented 17% of all first transplants (43 of 257) performed during this period. Patients were interviewed before orthotopic liver transplantation by a single psychiatrist and responses to a defined set of questions were entered into a clinical database. All 43 patients diagnosed with alcoholic liver disease and a comparison group of patients transplanted for diagnoses other than alcoholic liver disease received a postoperative questionnaire regarding past and present alcohol use. Patients enrolled in the study all had at least 7 mo of follow-up, with the median follow-up being 21 mo. Eighty-six percent of alcoholic liver disease patients (37 of 43) and 86% of patients in the comparison group (37 of 43) of ALD patients agreed to participate in the study. Nineteen percent of alcoholic liver disease patients (7 of 37) and 24% of patients in the comparison group (9 of 37) admitted to having used alcohol after orthotopic liver transplantation, wtih 8% (3 of 37) and 11% (4 of 37) currently using alcohol, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolongation of in vivo mouse islet allograft survival by modulation of MHC class I antigen.

Major histocompatibility complex class I-deficient islets from beta-2 microglobulin-deficient mice have been shown to have prolonged in vivo islet allograft survival. Additionally in vitro studies using the mixed lymphocyte islet coculture system have demonstrated a reduction in cytotoxic T lymphocyte activity against alloislets that have been pretreated with an antibody directed against MHC class I antigen. The clinical applicability of these findings are examined in this study, which evaluates the ability of MHC class I blocking antibody to prevent the in vivo destruction of alloislets. Recipients of allogenic islet transplants treated with phosphate-buffered saline or control F(ab')2 fragments rejected the transplanted alloislets in median times of 11.5 days and 11 days, respectively. Recipient mice treated with a monoclonal antibody or F(ab')2 fragments specific to the donor MHC class I antigen had significant prolongation in allograft survival (median allograft survival for both groups was 21 days) when compared with mice treated with PBS or control F(ab')2 fragment. These results demonstrate that treating recipients of alloislets with donor-specific MHC class I monoclonal antibody or the respective F(ab')2 fragments prolongs islet allograft survival. This confirms the importance of MHC class I antigen in the rejection of pancreatic islet allografts and suggests that blocking different domains on the MHC class I molecule could be used therapeutically in the protection of allografts from the immune system.

The increased efficacy and decreased nephrotoxicity of a cyclosporine liposome.

A potential approach to avoid the complications of systemic immunosuppression is to deliver immunosuppressive agents locally to the site of the allograft. Liposomes are phospholipid particles that allow delivery of drugs preferentially to the reticuloendothelial system. Since the liver is a primary component of the RES, we hypothesized that liposome technology could be utilized to deliver immunosuppressive agents locally to a transplanted liver, thereby avoiding the complications of systemically delivered immunosuppression. We evaluated this hypothesis with a prototypic cyclosporine liposome in a rat model. Pharmacokinetic studies of this liposome indicated earlier clearance from the systemic circulation and increased hepatic uptake relative to the standard intravenous form of CsA. Decreased nephrotoxicity was also shown in an ischemic kidney model in the rat. The immunosuppressive efficacy of this liposome was also tested in a rat liver transplant model. There was a significant increase in survival compared with standard intravenous CsA when both drugs were administered at a dose of 1.75 mg/kg/day for seven days posttransplant (P < .05, CsA liposome-treated versus CsA/saline-treated). There were no demonstrable early toxic effects or late toxic effects observed with follow-up to 100 days. These data indicate that CsA liposomes have potential for use as an immunosuppressive agent with increased efficacy and decreased nephrotoxicity relative to the commercially available form of intravenous CsA. This improved therapeutic index of a locally targeted drug may lead to fewer complications attributed to systemic immunosuppression.

Major histocompatibility complex class I deficiency prolongs islet allograft survival.

Because of islet allograft rejection, nonimmunosuppressed pancreatic islet allotransplantation has been unsuccessful for the treatment of type I diabetes. The role of major histocompatibility complex class I antigen expression on islet allograft survival was evaluated with the use of mice homozygous for a beta 2-microglobulin gene disruption. These mice express little if any functional major histocompatibility complex class I antigen. When these major histocompatibility complex class I-deficient islets were used as donors in an allogenic murine transplantation model, islet allograft survival was markedly prolonged. These results demonstrate a major importance for the alloresponse directed against major histocompatibility complex class I antigen.

Nonoperative management of biliary leaks after orthotopic liver transplantation.

Specific therapy should be instituted expeditiously once the diagnosis of a biliary leak has been made in patients who have undergone orthotopic liver transplantation. Controversy exists over whether to use nonoperative or operative management. The results of 325 consecutive orthotopic liver transplants in 297 adult and pediatric recipients were reviewed. The biliary tract was reconstructed using a choledochocholedochostomy anastomosis (254/325 or 78%) or a Roux-en-Y choledochojejunostomy anastomosis (71/325 or 22%). The incidence of biliary leaks was 23% (74/325). Overall, only 3% (10/325) of the orthotopic liver transplant recipients required operative repair of a biliary leak. Biliary leaks occurring in patients with Roux-en-Y choledochojejunostomy anastomoses (9/71 or 13%) commonly required operative repair (6/9 or 67%), whereas leaks that occurred in patients with choledochocholedochostomy anastomoses (65/254 or 26%) seldom required operative repair (4/65 or 6%). All choledochojejunostomy leaks occurred at the anastomosis, whereas choledochocholedochostomy leaks occurred either at the anastomosis (17/254 or 7%) or the T-tube insertion site (45/254 or 18%). Our study confirms that in centers with proficient endoscopic and interventional radiologic support, resolution of biliary leaks in orthotopic liver transplant patients can be achieved with nonoperative management.