Use of grafts procured from organ transplant recipients

BACKGROUND

Massive intracerebral bleeding may cause brain stem death in transplant (Tx) recipients early or late postTx. We addressed the question as to whether Tx recipients may safely be used as organ donors. In particular, it is feared that exposure to immunosuppressive drugs may render those organs unsuitable for Tx.

METHODS

We reviewed two case reports of liver grafts procured from Tx patients. In addition, we conducted a survey within United Kingdom Transplant Support Service Authority (UKTSSA) to delineate the UK experience in that area.

RESULTS

Donor 1 was an 50-year-old heart Tx recipient who became brain stem dead due to cerebral bleeding 8 months postTx. His liver was used in an 55-year-old patient with PBC who is alive and well more than 22 months postTx. Donor 2 was a 22-year-old kidney Tx patient who developed cerebral bleeding 4 years postTx. His liver was used in a 65-year-old patient with PBC who is doing well more than 27 months postTx. During the study period of 1989-1995, 13 organs (9 kidneys, 3 hearts, 1 liver) were procured from 6 brain stem dead Tx patients (3 long, 2 heart, and 1 kidney Tx patients). Seven recipients are enjoying satisfactory graft function 1 to 7 years postTx; one kidney Tx recipient was relisted 4 years postTx due to chronic rejection; five functionning grafts were lost to patient death; primary nonfunction was seen in one heart Tx recipient.

CONCLUSIONS

Tx patients can be successfully used as organ donors. In particular, chronic exposure to immunosuppression is not per se a contraindication to donation. Tx physicians confronted with the rare and tragic event of brain stem death in a Tx patient should not a priori exclude these patients from donation.

High pre-treatment serum hepatitis B virus titre predicts failure of lamivudine prophylaxis and graft re-infection after liver transplantation

BACKGROUND/AIMS

Orthotopic liver transplantation has an established role for the treatment of patients with chronic liver failure secondary to hepatitis B virus (HBV) infection. Unfortunately, recurrent infection of the graft can be associated with aggressive disease, and with diminished graft and patient survival. Currently, the role of nucleoside analogues for prevention of graft re-infection is being evaluated. Preliminary results are encouraging, but treatment failure has been associated with emergence of drug-resistant virus.

METHODS

We have studied ten consecutive patients who received lamivudine prophylaxis for prevention of HBV graft reinfection. Sequential sera, collected prelamivudine then during treatment before and after liver transplantation, were examined. Conventional serological markers were measured, as were serum viral DNA levels with a sensitive quantitative polymerase chain reaction assay.

RESULTS

Lamivudine treatment effected a reduction in serum HBV levels, but six patients still had measurable viral DNA at the time of transplantation. Five patients developed graft re-infection with lamivudine-resistant virus. Resistant virus emerged 8 to 15 months post-transplant. The likelihood of emergence of resistant virus was related to the pre-treatment serum HBV titre. Persistent serum viral DNA positivity and evidence of graft re-infection during the early post-transplant period did not predict the subsequent emergence of resistant virus.

CONCLUSIONS

Our observations suggest that the resistant species may be present in the viral quasispecies in the serum and liver of patients with high-level replication prior to lamivudine exposure. The resistant species can persist during lamivudine treatment prior to transplantation, and emerge following transplantation. These observations suggest strategies which might prevent the emergence of drug-resistant species, and imply that graft re-infection may be a preventable phenomenon.

Energy storage and cytokine response in patients undergoing liver transplantation

Overproduction of pro-inflammatory cytokines during surgery has been known to exert tissue-damaging and lethal effects on the host. Hypermetabolism-associated malnutrition, a common feature of patients with end-stage liver diseases, is related to the presence of a systemic inflammatory response, as reflected by enhanced levels of proinflammatory cytokines. The present study was designed to evaluate energy status of 29 liver transplant recipients, and to assess the relation of energy storage to post-operative cytokine response. The glycogen contents of the graft, and the recipient's abdominal muscle and old liver were measured. The plasma concentrations of tumour necrosis factor alpha, interleukin 1beta, interleukin 6, lactate, pyruvate and total ketone bodies were determined during and after surgery. In undernourished patients, ketone bodies seemed to be the major fuel available to muscle. The concentration of ketone bodies decreased rapidly after the incision, and remained at a low level after reperfusion. These patients had higher plasma levels of lactate/pyruvate ratio and aromatic amino acids during the anhepatic phase, followed by an exaggerated response of cytokines. Depletion of energy storage of the recipients may be involved in the deterioration of peri-operative energy metabolism and the exaggerated post-operative cytokine response.

Effect of peritransplant FTY720 alone or in combination with post-transplant tacrolimus in a rat model of cardiac allotransplantation

FTY720 is a recently discovered compound that is derived from the fungus Isaria sinclairii. Using a DA donor-to-LEW recipient rat combination, we assessed the efficacy of peritransplant FTY720 alone or in combination with post-transplant tacrolimus on the survival of cardiac allografts. Peritransplant FTY720 given orally at a dose of 5 mg/kg on days-1 and 0 prolonged graft survival from 5 to 13 days (P < 0.05). Combining peritransplant FTY720 with post-transplant tacrolimus resulted in a further prolongation of allograft survival. The lymphocyte count in transplanted rats decreased within 24 h to 46.6%. Analysis of lymphocyte subsets by FACS revealed that FTY720 affected the total population of CD3-bearing T cells while the ratio of CD4 to CD8 cells remained unchanged. Kidney and liver biochemistry remained elevated for 2 weeks. In conclusion, FTY720 is a powerful immunosuppressive agent when used as induction therapy and may have an additive effect--perhaps a synergistic one--with post-transplant tacrolimus.

Hepatocellular cancer: resection or transplantation

Surgery remains the treatment of choice for hepatocellular carcinoma (HCC). For HCC without underlying cirrhosis resection remains the mainstay treatment option. Prognosis depends on the stage of the tumor. Survival appears to be better for small (less than 5 cm) solitary tumors with negative resection margins and absence of vascular invasion. At present, liver transplantation does not have an established role in the treatment of HCC in a non-cirrhotic liver. Because of the high recurrence rate, it should not be considered for more advanced disease which is not amenable to resection. The surgical approach in cirrhotics depends not only on the stage of the tumor but also on the liver functional reserve. Tumor size, presence of multifocal disease, and vascular invasion determine the risk of HCC recurrence after resection, and the functional stability of the liver determines both resectability and outcome. In societies in which transplantation is not available, small tumors will be treated with liver resection. The outcome in patients with well preserved liver function is relatively good, at least in the medium term. However, recurrent tumor and progressive hepatic decompensation have significant adverse effects on long-term survival. Poor functional reserve may be associated with significant perioperative mortality and lower survival due to progressive liver failure. In our opinion, for small cirrhosis-related HCCs, liver transplantation offers better long-term prospects than resection. Therefore, if liver transplantation is available as an option it should be considered as the treatment of choice, particularly for younger patients with otherwise good life expectancy.

Repeat orthotopic liver transplantation in the 1990s: is it justified?

Repeat orthotopic liver transplantation (ReOLT) is controversial because of limited donor organ availability and increasing health care costs. The purpose of this study is to analyse and compare the outcome of reOLT in the 1990s and the 1980s. Prospective data of 1077 adult OLT from the Liver Unit database were used for the study. The log-rank test was used for statistical analysis. Between January 1982 and December 1996, a total of 1077 adult OLTs were performed including 107 reOLTs. The proportion of retransplants decreased from 13% in the 1980s to 9% in the 1990s. There was a significant improvement in outcome; the overall 1-year graft and patient survival for reOLT was 60% and 74% in the 1990s compared to 29% (P < 0.0001) and 51% (P < 0.0001) in the 1980s. In the second half of the study between January 1990 and December 1996, 732 adult OLTs were undertaken including 70 (9%) reOLTs which consisted of 62 second, 7 third and 1 fourth grafts. The main indications for retransplantation were chronic rejection (31%), hepatic artery thrombosis (30%), primary non-function (16%), ischaemic injury (11%), recurrent disease (6%) and biliary complications (6%). During this period, the 1-year graft survival for all reOLTs was significantly lower than for primary OLTs (67% vs 78%, P < 0.001). The timing of reOLT was found to be associated with graft survival; 1-year graft survival for early reOLT (< 30 days) was 50% compared to 73% for late reOLT (P < 0.001). The worse outcome associated with early reOLT is explained by the poor preoperative medical condition of patients who were retransplanted from intensive care. Subgroup analysis of indications for reOLT revealed 1-year graft survival of 81% for late vascular complications, 75% for early vascular complications, 69% for chronic rejection and 30% for primary non-function. One-year graft survival rates for third and fourth grafts were 42% and 0%, respectively. Graft survival and resource utilisation in patients who received a late regraft for the first time is now comparable to that for primary OLT. The favourable overall results should not preclude this group of patients from consideration for reOLT.

Maintained function of primary human hepatocytes by cellular interactions in coculture: implications for liver support systems

The application of primary hepatocytes in hybrid artificial liver systems has been hampered by the gradual loss of differentiated morphology and function in vitro. Therefore, we have established a coculture model of autologous human hepatocytes and biliary epithelial cells (BEC) in collagen gel in the presence of hepatotrophic growth factors. Furthermore, we examined the effect of hepatocyte cell perfusion in a women multicompartment capillary membrane system. Normal hepatocytes isolated from human liver produced albumin for more than 2 weeks in serum-free media, and were further stimulated by conditioned medium. When cocultured with BEC, albumin secretion was greatly enhanced, suggesting that cellular interactions promote tissue-specific differentiation. When perfused in bioreactors, albumin levels were maintained at steady state for longer than 2 weeks. These data indicate that differentiation of primary hum hepatocytes can be maintained by coculture interactions and three-dimensional hybrid organ devices, providing appropriate growth factors and matrix for tissue regeneration.

Encouraging results of split-liver transplantation

BACKGROUND

Liver donor shortage presently accounts for a 10 per cent waiting list mortality rate. Split-liver transplantation (SLT) can improve utilization of this scarce resource.

METHODS

Twenty-four SLTs (11 left, 13 right grafts) from 13 livers were performed in 23 patients (nine adults, 14 children), comprising 4.5 per cent of all orthotopic liver transplants (14 urgent or emergency, ten elective). The left graft comprised segments II and III, whereas the right graft comprised segments V-VIII in eight cases, IV-VIII in three, and segments I, IV-VIII, and I, V-VIII in one case each. Additional arterial extension grafts were required in six of 24 cases, and portal venous interposition graft in one.

RESULTS

Twenty-one grafts showed good initial function, with one primary non-function and two initial poor function. The median peak aspartate aminotransferase level was 782 (range 94-2301) and 982 (range 382-2520) units/l for left and right grafts respectively. Five patients died (all urgent recipients), all within the first 30 days after surgery. Two SLT recipients underwent subsequent retransplantation. All ten elective recipients are alive. The 1-year actuarial patient and graft survival rates at a median follow-up of 20 months were 78 and 68 per cent respectively.

CONCLUSION

These encouraging results compare favourably with those of reduced-size and whole-liver transplantation and justify wider application of this technique, thereby optimizing donor resource use.

[Use of normal human hepatocytes in a hybrid organ system]

Using the bioreactor model developed by J. Gerlach, we examined the potential of normal human hepatocytes for application in bioartificial liver devices. From normal human donor livers 1.5 x 10(8) hepatocytes were isolated. Hepatocytes were perfused in a woven multi-compartment capillary system in serum-free culture medium containing ammoniachloride over a period of 2 weeks. These cells demonstrated a well differentiated ultrastructure with formation of junctional complexes and bile canaliculi between adjacent cells. During reactor run, a constant albumin synthesis with levels above 11 mg/ml and maintenance of urea production and lignocaine metabolism (MEGX-test) were detected. These initial results indicate that normal human hepatocytes express typical morphology and ultrastructure and are able to keep differentiated functions in suitable perfusion models. Combination of the distinct human liver cell populations might enable promotion of further specific functions (clotting factors) and induction of liver cell proliferation.

Postperfusion energy metabolism of steatotic graft and its relation to early graft viability following liver transplantation

The present study was designed to assess energy metabolism of steatotic grafts and to determine its relation to early graft viability. Graft biopsies were taken, and the triglyceride content was determined in 29 grafts for the assessment of steatosis. The peak aspartate aminotransferase level and the concentrations of lactate and pyruvate were strongly correlated with the triglyceride content, suggesting that steatotic grafts are more vulnerable to preservation or reperfusion injury and that glucose oxidation is inhibited postoperatively in the steatotic grafts. Ketogenesis, an alternative pathway to produce energy substrates, was not accelerated even when the steatotic grafts produced more free carnitine to enhance the beta-oxidation of fatty acids. The deterioration of energy metabolism was associated with the increase in prothrombin time ratio, hepatocyte growth factor, and hyaluronic acid that reflected graft viability. Deterioration of postperfusion energy metabolism in the steatotic grafts may be involved in the development of irreversible graft damage.

[Primary angiosarcoma of the liver]

Hepatic angiosarcoma (AS) is a rare tumor with a fatal course. It represents 1-2% of all primary hepatic tumors and it is the most frequent primary mesenchymal tumor of the liver. Recently its incidence is dramatically increased because of its epidemiological association with exposure to thorotrast, vinyl chloride and other carcinogens. We present the epidemiological, clinical, diagnostic and therapeutic features of 6 patients with primary hepatic AS. No apparent predisposing factors were present. At presentation symptoms, signs and liver function tests were not specific. Four patients presented with metastatic disease: lung (2), peritoneum (1), bone and spleen (1). At time of diagnosis tumor was bilobar in 4 cases and in 2 of whom was multifocal. Median tumor size was 10.5 cm (range: 4-20 cm). Four patients with extrahepatic disease were conservatively treated with chemotherapy (VAC) and the longest survival was 8 months and 2 with tumor confined to the liver were transplanted but both had an early recurrence at 3 and 5 months post-tx respectively and the longest survival was 10 months. These disappointing results confirm the aggressive nature of hepatic AS. An early diagnosis is needed and the radical resection of the tumor is still the best form of treatment.