Is the use of marginal donors justified in liver transplantation? Analysis of results and proposal of modern criteria

Lower expression of Nrf2 mRNA in older donor livers: a possible contributor to increased ischemia-reperfusion injury?

BACKGROUND

The cellular mechanisms involved in mediating cytoprotection against ischemia-reperfusion (IR) injury are not well understood. In animal models, NF-E2-related factor-2 (Nrf2) protects against IR injury by transcriptional activation of phase II antioxidants. Here, we investigate how the expression of Nrf2 mRNA in human donor livers in the setting of liver transplantation (LT) correlates with the histological damage associated with IR injury and whether or not this influences the outcome of LT.

METHODS

Pairs of biopsies were acquired from 14 donor livers; the first biopsy of each pair was taken at the start of the retrieval operation, prior to the IR phase of LT and the second at the end of transplantation. RNA was extracted from snap frozen tissue and cDNA was prepared. Nrf2 mRNA expression was determined using real-time polymerase chain reaction (PCR). The modified Suzuki scoring system was used for histological grading of IR injury and relevant donor, recipient, and after LT clinical data were compiled.

RESULTS

Nrf2 expression was observed in all biopsies, both before and after IR. Some donor organs had greater expression of Nrf2 mRNA before IR injury, and these organs had lower Suzuki scores and better liver functions (ALT) after LT. Donors of livers with greater Nrf2 levels were significantly younger (40.5 yrs, range 28-53 yrs) than those with low Nrf2 levels (55.5 yrs, range 48-61 yrs), P<0.05.

CONCLUSION

Livers from older donors have lower levels of Nrf2 perhaps exposing these organs to more IR-related damage.

Pharmacokinetics of cyclosporine in recipients of marginal versus standard liver transplants

In the field of transplants, the practice of using marginal donor livers has become widely accepted, yielding good clinical results. This study investigated and compared the pharmacokinetics of cyclosporine in marginal and standard liver transplant recipients. Twenty-four de novo liver transplant patients, 12 with marginal and 12 with standard (normal) grafts, were treated with a microemulsion formulation of cyclosporine (capsules 100 mg) as immunosuppressive therapy. Blood concentration profiles were measured, and pharmacokinetic calculations performed at days 3 and 10 after transplantation. Different sampling strategies to predict drug exposure (AUC(0-12 h)) were compared, and the best limited-sampling strategies to monitor the desired blood levels were determined. Marginal and standard patients showed a significant difference in blood concentration and pharmacokinetic profiles of cyclosporine at the day 10 post-transplantation. Blood concentration at 4h (C(4 h)) was the single best timepoint to estimate AUC(0-12 h) in marginal liver transplant (r(2)=0.700), while C(2h) was confirmed to be the optimal choice with standard graft (r2=0.720). Two blood samples at 2 and 6 h significantly improved the prediction model in both groups (r2=0.920). Our data suggest that patients receiving a marginal liver transplant present a different pharmacokinetic profile of cyclosporine from those receiving standard graft, which should be taken into account in dosing the patient to avoid subtherapeutic blood concentrations or toxic effects.

Does tacrolimus offer virtual freedom from chronic rejection after primary liver transplantation? Risk and prognostic factors in 1,048 liver transplantations with a mean follow-up of 6 years

Tacrolimus has proven to be a potent immunosuppressive agent in liver transplantation (LT). Its introduction has led to significantly less frequent and severe acute rejection. Little is known about the rate of chronic rejection (CR) in primary LT using tacrolimus therapy. The aim of the present study is to examine the long-term incidence of CR, risk factors, prognostic factors, and outcome after CR. The present study evaluated the development of CR in 1,048 consecutive adult primary liver allograft recipients initiated and mostly maintained on tacrolimus-based immunosuppressive therapy. They were evaluated with a mean follow-up of 77.3 +/- 14.7 months (range, 50.7 to 100.1 months). To assess the impact of primary diagnosis on the rate and outcome of CR, the population was divided into 3 groups. Group I included patients with hepatitis C virus (HCV)- or hepatitis B virus (HBV)-induced cirrhosis (n = 312); group II included patients diagnosed with primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), or autoimmune hepatitis (AIH; n = 217); and group III included patients with all other diagnoses (n = 519). Overall, 32 of 1,048 patients (3.1%) developed CR. This represented 13 (4.1%), 12 (5.5%), and 7 patients (1.3%) in groups I, II, and III, respectively. The relative risk for developing CR was 3.2 times greater for group I and 4.3 times greater for group II compared with group III. This difference was statistically significant (P =.004). The incidence of acute rejection and total number of acute rejection episodes were significantly greater in patients who developed CR compared with those who did not (P <.0001). Similarly, the mean donor age for CR was significantly older than for patients without CR (43.0 v 36.2 years; P =.02). Thirteen of the 32 patients (40.6%) who developed CR retained their original grafts for a mean period of 54 +/- 25 months after diagnosis. Seven patients (21.9%) underwent re-LT, and 12 patients (38.3%) died. Serum bilirubin levels and the presence of arteriopathy, arterial loss, and duct loss on liver biopsy at the time of diagnosis of CR were significantly greater among the 3 groups of patients. In addition, patient and graft survival for group I were significantly worse compared with groups II and III. We conclude that CR occurred rarely among patients maintained long term on tacrolimus-based immunosuppressive therapy. When steroid use is controlled, the incidence of acute rejection, mean donor age, HBV- and/or HCV-induced cirrhosis, or a diagnosis of PBC, PSC, or AIH were found to be predictors of CR. Greater values for serum bilirubin level, duct loss, arteriopathy, arteriolar loss, and presence of HCV or HBV were found to be poor prognostic factors for the 3 groups; greater total serum bilirubin value (P =.05) was the only factor found to be significant between patients who had graft loss versus those who recovered.

Outcome of transplantation of organs procured from bacteremic donors

BACKGROUND

Transplantation of organs from donors who are bacteremic is controversial. We examined the outcome of recipients of solid organs from donors with bacteremia and/or fungemia at the time of organ recovery.

METHODS

All organ donors from a single organ procurement organization between January 1990 and December 1996 were retrospectively analyzed. We calculated rates of transmission from bacteremic or fungemic donors to their recipients and compared the graft and patient survival rates for recipients of these organs with those for recipients of organs from non-bacteremic donors.

RESULTS

There were 95 (5.1%) bacteremic donors from a total of 1775, from whom 212 recipients received organs. Forty-six (48%) of the bacteremic donors had pathogens in their blood. Among the 101 recipients of organs from these, no evidence of transmission could be documented. (0% transmission rate, 95% CI 0-3). The remaining 49 donors had either Staphylococcus epidermidis or other unlikely pathogens recovered from the blood. Examination of the 111 recipients of organs from these donors also found no evidence for transmission (0% transmission rate, 95% CI 0-3). Of the 212 recipients, 193 (91%) received a mean of 3.8+/-2.5 days of antibiotics postoperatively. The 30-day graft and patient survival for recipients of organs from bacteremic donors was not significantly different from recipients of organs from nonbacteremic donors (P = 0.695 for patient survival, and P = 0.310 for graft survival).

CONCLUSIONS

Organs transplanted from bacteremic donors do not transmit bacterial infection or result in poorer outcomes. Use of organs from these donors could help increase organ availability.