Adrian H. Cotterell

Human complement regulatory proteins protect swine-to-primate cardiac xenografts from humoral injury

The susceptibility of xenografts to hyperacute rejection is postulated to reflect in part failure of complement regulatory proteins (CRPs) to control activation of heterologous complement on graft endothelium. To test this concept, transgenic swine expressing the human CRP decay accelerating factor and CD59 were developed using a novel expression system involving transfer of the proteins from erythrocytes to endothelial cells. Hearts from transgenic swine transplanted into baboons had markedly less vascular injury and functioned for prolonged periods compared to hearts from nontransgenic swine. These results indicate that expression of human CRPs in xenogeneic organs may contribute to successful xenografting and suggest that intercellular protein transfer might be a useful approach for expression of heterologous proteins in endothelial cells.

Effects of interferon treatment on liver histology and allograft rejection in patients with recurrent hepatitis C following liver transplantation

Recurrent hepatitis C after liver transplantation remains a significant cause of graft loss and retransplantation. Although treatment of recurrent hepatitis C with interferon‐based regimens has become widely accepted as safe and can lead to sustained virologic clearance of hepatitis C virus (HCV) RNA, long‐term histologic improvement and the risk of precipitating graft rejection remain controversial. The present study is a retrospective evaluation of the clinical and histological consequences of treating recurrent hepatitis C with interferon‐based therapy in a selected group of liver transplant recipients. Twenty‐three liver transplant recipients with recurrent hepatitis C and histologic evidence of progressive fibrosis completed at least 6 months of interferon, 83% of whom received pegylated‐interferon α‐2b; only 4 tolerated ribavirin. Overall, 11 patients (48%) had undetectable HCV RNA at the end of 6 months of treatment. Of these patients, 3 remained HCV RNA–negative on maintenance interferon monotherapy for 33 months, and the other 8 (35%) completed treatment and remained HCV RNA–undetectable 24 weeks after discontinuation of interferon. Overall necroinflammatory activity in liver biopsies obtained 2 years after HCV RNA became undetectable decreased significantly (7.73 ± 2.37 vs. 5.64 ± 2.94 units before and after treatment, respectively; P = .016). However, 5 of these 11 patients had no histologic improvement in follow‐up liver histology. Liver biopsies in the 12 nonresponders demonstrated disease progression. Of the 23 patients treated with interferon, 8 (35%) had evidence of acute or chronic rejection on posttreatment liver biopsy, most of whom had no previous history of rejection (P < .01 for comparison of pretreatment and posttreatment prevalence of histologic rejection), and 2 experienced graft loss from chronic rejection, requiring retransplantation. In conclusion, interferon treatment of recurrent hepatitis C does not consistently improve histologic disease after virologic response, and it may increase the risk of allograft rejection. (Liver Transpl 2004;10:850–858.)

Histologic recurrence of chronic hepatitis C virus in patients after living donor and deceased donor liver transplantation

Hepatitis C virus (HCV) recurs in nearly all patients after liver transplantation. This recurrence is associated with progressive fibrosis and graft loss. It remains unclear whether the natural course of HCV recurrence is altered in patients who undergo living donor liver transplantation (LDLT). We conducted a prospective, controlled trial using protocol liver biopsies to evaluate the histologic outcome of recurrent HCV in 23 patients who underwent LDLT and 53 patients who underwent transplantation with a deceased donor liver (DDLT) during the same period of time. Patients who did not survive at least 6 months after transplantation or who had hepatocellular carcinoma or any other coexistent liver disease were excluded from analysis. All patients underwent protocol liver biopsy at 6 months and at 12 months and at yearly intervals thereafter. The mean age, sex, racial distribution, and serum HCV RNA and the percentage of patients with genotype 1 were similar in the 2 groups of patients. The model for end‐stage liver disease score at the time of transplantation was slightly lower in patients who underwent LDLT, but this difference was not significant. The distribution of immunosuppression agents used, the mean doses of calcineurin agents, the use of mycophenolate mofetil, and the dose and tapering schedule for prednisone were similar in both groups of patients. The mean duration of follow‐up was 40 months. No significant difference in either graft or patient survival or the percentage of patients who developed acute rejection was noted in the 2 groups of patients. At 48 months, graft and patient survival were 82% and 82% and 75% and 79% for patients who underwent DDLT and LDLT, respectively. The degree of hepatic inflammation increased stepwise over 3 years but was not significantly different in the 2 patient groups. In contrast, the mean fibrosis score and the percentage of patients with fibrosis increased stepwise after DDLT but appeared to plateau 12 months after LDLT. At 36 months, fibrosis was present in 78% of DDLT patients, and mean fibrosis score was 1.9, compared with 59% with fibrosis and a mean score of .9 after LDLT. In conclusion, these data strongly suggest that fibrosis progression from recurrent HCV is not more severe in patients after LDLT. (Liver Transpl 2004;10:1248–1255.)

The humoral immune response in humans following cross-perfusion of porcine organs

A major question in xenotransplantation is the nature of the humoral response that would occur following the transplantation of a xenogeneic organ into an immunosuppressed recipient as such a response could mediate delayed types of injury to the graft. To begin to address this issue we characterized the changes in the properties of xenoreactive antibodies occurring in patients exposed to porcine organs under conditions simulating transplantation. In two patients whose blood had been cross-perfused through porcine livers as a treatment for hepatic failure, the titer of xenoreactive IgM increased by four-fold and the titer of xenoreactive IgG increased by sixty-fold within ten days after perfusion procedures. The xenoreactive IgM and IgG antibodies were specific for Galα1–3Gal based on binding to porcine endothelial cells and bovine thyroglobulin, which express this determinant, and on the decrease in binding following treatment of porcine endothelial cells or bovine thyroglobulin with α-galactosidase. The sequential addition to endothelial cells of amounts of serum known to saturate antibody-binding sites obtained before and ten days after perfusion of porcine organs revealed no increase in binding of IgM above the level observed with serum obtained before perfusion, suggesting that new determinants were not identified. Moreover, the functional avidity of binding to porcine endothelial cells of IgM in serum obtained before and ten days after perfusion of porcine organs was unchanged. Even at later times, the presence of newly elicited antibodies against porcine aortic endothelial cell targets was not detected. Thus, exposure to porcine antigens in a vascularized organ results in increases in the levels of xenoreactive IgM and IgG antibodies—however, these antibodies exhibit properties similar to natural antibodies.

MicroRNA profiles in allograft tissues and paired urines associate with chronic allograft dysfunction with IF/TA

Despite the advances in immunosuppression, renal allograft attrition over time remains unabated due to chronic allograft dysfunction (CAD) with interstitial fibrosis (IF) and tubular atrophy (TA). We aimed to evaluate microRNA (miRNA) signatures in CAD with IF/TA and appraise correlation with paired urine samples and potential utility in prospective evaluation of graft function. MiRNA signatures were established between CAD with IF/TA versus normal allografts by microarray. Validation of the microarray results and prospective evaluation of urine samples was performed using real‐time quantitative‐PCR (RT‐qPCR). Fifty‐six miRNAs were identified in samples with CAD‐IF/TA. Five miRNAs were selected for further validation based on array fold change, p‐value and in silico predicted mRNA targets. We confirmed the differential expression of these five miRNAs by RT‐qPCR using an independent set of samples. Differential expression was detected for miR‐142‐3p, miR‐204, miR‐107 and miR‐211 (p < 0.001) and miR‐32 (p < 0.05). Furthermore, differential expression of miR‐142‐3p (p < 0.01), miR‐204 (p < 0.01) and miR‐211 (p < 0.05) was also observed between patient groups in urine samples. A characteristic miRNA signature for IF/TA that correlates with paired urine samples was identified. These results support the potential use of miRNAs as noninvasive markers of IF/TA and for monitoring graft function.

Surveillance for Hepatocellular Carcinoma in Patients with Cirrhosis Improves Outcome

OBJECTIVE Liver transplantation has become an effective treatment for cirrhotic patients with early-stage hepatocellular carcinoma. We hypothesized that the quality of surveillance for hepatocellular carcinoma influences prognosis by affecting access to liver transplantation. METHODS A total of 269 patients with cirrhosis and hepatocellular carcinoma were retrospectively categorized into 3 groups according to quality of surveillance: standard-of-care (n=172) (group 1); substandard surveillance (n=48) (group 2); and absence of surveillance in patients not recognized to be cirrhotic (n=59) (group 3). RESULTS Three-year survival in the 60 patients who underwent liver transplantation was 81% versus 12% for patients who did not undergo transplantation (P<.001). The percentages of patients who underwent transplantation according to tumor stage at diagnosis (T1, T2, T3, and T4) were 58%, 35%, 10%, and 1%, respectively. Hepatocellular carcinoma was diagnosed at stages 1 and 2 in 70% of patients in group 1, 37% of patients in group 2, and only 18% of patients in group 3 (P <.001). Liver transplantation was performed in 32% of patients in group 1, 13% of patients in group 2, and 7% of patients in group 3 (P<.001). Three-year survival from cancer diagnosis in patients in group 3 (12%) was significantly worse than in patients in group 1 (39%) or group 2 (27%) (each P<.05). Eighty percent of patients in group 3 had subtle abnormalities of cirrhosis on routine laboratory tests. CONCLUSION The quality of surveillance has a direct impact on hepatocellular carcinoma stage at diagnosis, access to liver transplantation, and survival.

Adult Living Donor Versus Deceased Donor Liver Transplantation: A 6‐Year Single Center Experience

No long‐term (>3 years) prospective comparison of adult‐to‐adult living donor liver transplantation (A2ALLTx) to adult deceased donor liver transplantation (ADDLTx) has been reported.

Non-resective ablation therapy for hepatocellular carcinoma: effectiveness measured by intention-to-treat and dropout from liver transplant waiting list

Abstract:  Background:  Orthotopic liver transplantation (OLT) for patients with small hepatocellular carcinoma (HCC) is widely accepted, and the usefulness of local ablation techniques as a bridge for liver transplantation is still under investigation.

Establishing the molecular pathways involved in chronic allograft nephropathy for testing new noninvasive diagnostic markers.

Background. Chronic allograft nephropathy (CAN) is a cause of graft loss. The multistage processes that result in CAN are poorly understood. Noninvasive assays for detecting allograft dysfunction and predicting long-term outcomes are a priority in transplantation (Tx). Methods. Renal tissue from kidney transplant patients (KTP) with CAN (n=11) and normal kidneys (NK; n=7) were studied using microarrays. Markers resulting from the microarray analysis (transforming growth factor [TGF]-β, epidermal growth factor receptor [EGFR], angiotensinogen [AGT]) were tested in urine (Ur) and peripheral blood (PB) samples from the CAN patients (collected at the biopsy time) using reverse-transcriptase real-time polymerase chain reaction. Ur and PB samples from long-term KTP with stable renal function (SRF; n=20) were used as control. Results. Assuming unequal variances between CAN and NK, using a false discovery rate of 0.005, and running 1,000 of all possible permutations, 728 probe sets were differentially expressed. Genes related to fibrosis and extracellular matrix deposition (i.e., TGF-β, laminin, gamma 2, metalloproteinases-9, and collagen type IX alpha 3) were up-regulated. Genes related to immunoglobulins, B cells, T-cell receptor, nuclear factor of activated T cells, and cytokine and chemokines receptors were also upregulated. EGFR and growth factor receptor activity (FGFR)2 were downregulated in CAN samples. AGT, EGFR, and TGF-β levels were statistical different in urine but not in blood samples of CAN patients when compared to KTP with SRF (P<0.001, P=0.04, and P<0.001, respectively). Conclusions. Genes related to fibrosis, extracellular matrix deposition, and immune response were found up-regulated in CAN. Markers resulting from the microarray analysis were differentially expressed in Ur samples of the CAN patients and in concordance with the microarray profiles.

Hepatitis C virus infection and kidney transplantation : Predictors of patient and graft survival

Background. The effect of hepatitis C virus (HCV) infection on patients undergoing kidney transplantation (KTx) is uncertain. This study aimed to evaluate the outcomes of our HCV+/end-stage renal disease (ESRD) patient population based on the therapeutic option including KTx or continuation in dialysis. Methods. KTx performed at Virginia Commonwealth University Hospital between January 2000 and December 2004 were tracked prospectively. Forty-three out of a total of 394 KTx patients included in the analysis were HCV+. A group of 52 contemporaneous HCV+/ESRD patients listed, but never transplanted, was also analyzed. HCV-negative transplanted patients were used as the control group. Results. Patient survival posttransplantation was 81.4% and 68.5% at 1 and 3 years in the HCV+ group, and 97.1% and 92.9% at 1 and 3 years in the HCV- group, respectively (P=0.001). Graft survival was 81.2% and 64.1% at 1 and 3 years in the HCV+ group, and 93.2% and 84.1% at 1 and 3 years posttransplantation in the HCV- group (P=0.01). Univariate analysis identified Knodell score as a predictor of mortality in HCV+ patients (P=0.04). Cox proportional hazards multivariate analysis identified deceased donor (P=0.02), previous kidney transplant (P=0.007), pretransplant diabetes (P=0.05), and Knodell Score (P=0.012) as predictors of patient mortality. Patient survival was superior in HCV+ patients undergoing KTx versus remaining on dialysis. Conclusions. Patients with ESRD/HCV+ benefit from KTx without achieving the excellent survival of HCV-/ESRD patients. Liver biopsy is a useful tool to identify advanced liver disease at pretransplantation time.