Post-transplant Biopsies Research Articles

Predictors of De Novo Nonalcoholic Fatty Liver Disease After Liver Transplantation and Associated Fibrosis.

Nonalcoholic fatty liver disease (NAFLD) can occur de novo in patients undergoing liver transplantation (LT) for indications other than NAFLD, and it has been increasingly recognized as a complication in the post-LT setting. This study aims to better characterize de novo NAFLD after LT by identifying risk factors for its development, describing incidence and extent of fibrosis, assessing the diagnostic utility of noninvasive serum fibrosis algorithms, and comparing survival to those without NAFLD. This was a retrospective single-center analysis of de novo NAFLD in a post-LT cohort. Those whose primary indication for LT was nonalcoholic steatohepatitis (NASH) were excluded. Risk factors were analyzed by univariate and multivariate analyses. De novo NAFLD and fibrosis were assessed on posttransplant liver biopsies, and noninvasive fibrosis scores were calculated from concomitant blood tests. After applying the exclusion criteria, 430 for-cause post-LT biopsies were evaluated; 33.3% (n = 143) had evidence of de novo steatosis and/or NASH at a median of 3.0 years after transplant. On multivariate analysis, body mass index (BMI; odds ratio [OR], 1.12; P < 0.001), diabetes mellitus (OR, 3.01; P = 0.002), hepatitis C virus (OR, 4.61; P < 0.001), weight gain (OR, 1.03; P = 0.007), and sirolimus use (OR, 3.11; P = 0.02) were predictive of de novo NAFLD after LT. Significant fibrosis (≥F2) was present in almost 40% of the cohort. Noninvasive serum fibrosis scores were not useful diagnostic tests. There was no significant difference in the short-term or longterm survival of patients who developed de novo NAFLD. In conclusion, diabetes, BMI, weight gain after LT, and sirolimus-based immunosuppression, in keeping with insulin resistance, were the only modifiable factors associated with development of de novo NAFLD. A significant proportion of patients with de novo NAFLD had fibrosis and given the limited utility of noninvasive serum fibrosis algorithms, alternative noninvasive tools are required to screen for fibrosis in this population. There was no significant difference in the short-term or longterm survival of patients who developed de novo NAFLD.

Efficacy and Safety of Echocardiographic Guidance for Post-Transplant Endomyocardial Biopsy Sampling

Efficacy and Safety of Echocardiographic Guidance for Post-Transplant Endomyocardial Biopsy Sampling

Efficacy and Safety of Echocardiographic Guidance for Post-Transplant Endomyocardial Biopsy Sampling

Background: Endomyocardial biopsy is a very useful procedure to assess acute rejection in transplant patients, but it can causeseveral complications.Objective: The purpose of this study is to demonstrate the efficacy and safety of echocardiography as a guide for endomyocardialbiopsy sampling.Methods: A retrospective analysis of transplant patients undergoing endomyocardial biopsies was carried out between November2004 and November 2016. Demographic data and complications were analyzed with descriptive statistics.Results: A total of 200 patients underwent 2,665 endomyocardial biopsies, with an average of 13 procedures per patient. Complicationsoccurred in 5 patients: 2 pneumothorax (0.1%) and 3 transient alterations in the electrocardiogram (0.1%), and vascular accesscould not be achieved in 25 patients (0.9%). No patient died during the procedure or required emergency surgery to treat thecomplications.Conclusion: Endomyocardial biopsy guided by echocardiography is a safe procedure with a low rate of complications.

Histological picture of antibody-mediated rejection without donor-specific anti-HLA antibodies: Clinical presentation and implications for outcome.

In this cohort study (n=935 transplantations), we investigated the phenotype and risk of graft failure in patients with histological criteria for antibody-mediated rejection (ABMR) in the absence of circulating donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA), and compared this to patients with definite ABMR and HLA-DSA-positivity. The histological picture did not differ between HLA-DSA-positive (n=85) and HLA-DSA-negative (n=123) cases of ABMR histology, apart from increased complement split product 4d (C4d) deposition in the peritubular capillaries in HLA-DSA-positive cases. Histology of ABMR without HLA-DSA was more transient than DSA-positive ABMR, and patients with ABMR histology without HLA-DSA had graft survival superior to that of HLA-DSA-positive patients, independent of concomitant T cell-mediated rejection (38.2%) or borderline changes (17.9%). Multivariate analysis showed that the risk of graft failure was not higher in patients with histological picture of ABMR (ABMRh ) in the absence of HLA-DSA, compared to patients without ABMRh . Despite an association between C4d deposition and HLA-DSA-positivity, using C4d deposition as alternative for the DSA criterion in the diagnosis of ABMR, as proposed in Banff 2017, did not contribute to the prognosis of graft function and graft failure. We concluded that biopsies with ABMRh but without detectable HLA-DSA represent a distinct, often transient phenotype with superior allograft survival.

Short- and Long-Term Outcomes of Live Donor Renal Allografts From Older and Younger Donors

BackgroundThe rising demand for living renal donors has led to the recruitment of older donors. Findings vary, but these grafts appear to survive as long as grafts from standard criteria deceased and expanded criteria deceased donors. We investigated the effects of donor age ≥65 years and the presence or absence of donor antihypertensive therapy on patient condition 1 year after transplantation, and retrospectively examined 1-year (273 patients), 3-year (217 patients), and 5-year (140 patients) patient and graft survival. MethodsWe divided 273 donor-recipient pairs into Group Y (donor age <65 years, n = 224) and Group O (donor age ≥65 years, n = 49). Group O was subdivided into donors receiving treatment for hypertension (subgroup O-1, n = 16) and those not receiving treatment for hypertension (subgroup O-2, n = 33). We compared results of 1 hour post-transplant biopsies and looked at a small number of 1 year post-transplant biopsies. ResultsAlthough a significantly larger percentage of recipients from younger donors were undergoing preemptive transplantation, and the incidence of arteriosclerosis was significantly higher in the Group O kidneys, there were no significant differences between the 2 groups in terms of patient or graft survival at 1, 3, or 5 years; serum creatinine levels; or number of episodes of acute rejection. The presence or absence of donor antihypertensive treatment had no effect. ConclusionsWe found that donor age ≥65, with or without antihypertensive treatment, had no effect on graft or patient survival.

Patología del trasplante cardiaco en el Perú: Experiencia con 61 casos en un centro de referencia nacional

To describe the histopathological characteristics of explanted hearts and post-transplant biopsy specimens at a national reference center in Peru. A case series study of patients who underwent heart transplantation between March 2010 and February 2018. Sixty-one (61) transplanted patients with a mean age of 40.1 years (range: 9-66 years). Five cases (8.2%) initially diagnosed as dilated cardiomyopathy were reclassified after the histopathological study. The three leading causes of primary disease after transplantation were: idiopathic dilated cardiomyopathy (50.8%), ischemic cardiomyopathy (16.4%), and valvular cardiomyopathy (6.6%). The mean follow-up was 2.8 years. The post-transplant survival rate was 85.1% at 1 year and 82.8% at 5 years. Moderate/severe acute cellular rejection occurred in 12 patients (21.1%) and antibody-mediated rejection occurred in 3 patients (5.3%). Routine histopathological evaluation of the explanted heart is essential to confirm the etiology of heart failure, especially in cases clinically diagnosed as dilated cardiomyopathy. In addition, routine follow-up through endomyocardial biopsies shows that acute cellular rejection is still a frequent complication after a heart transplant, especially within the first year, and that antibody-mediated rejection has a low incidence in our population.

An Overview of Liver Transplant Pathology: Data from a Tertiary Referral Centre in Western India

Introduction and aim. 1. Study of liver explants - Etiologic types of end-stage chronic liver disease (ESCLD) and acute liver failure (ALF) in adults and children. 2. Assessment of donor steatosis and incidental granulomas. 3. Post-transplant liver biopsies.Material and methods. Specimens of 180 explant hepatectomies, 173 donor wedge and 30 core liver biopsies, and 58 post transplant liver biopsies received in our department from April 2013 to March 2017.Results. 1. Most common causes of ESCLD in adults were: alcohol related (30.32%), hepatitis virus related (18.71%) and non-alcoholic steatohepatitis related (18.06%); and in children < 12 years were: biliary atresia (27.27%), autoimmune disease (18.18%) and Wilson’s disease (18.18%). Most common causes of ALF in adults and children were anti-tubercular therapy induced and idiopathic, respectively. 2. Prevalence rate of moderate steatosis (between 30-60%) was 4.28%. Incidental granulomas were seen in 5 cases. 3. Most common diagnoses of post-transplant biopsies in adults included acute cellular rejection (ACR) (36.17%), recurrence of viral disease (8.51%) and moderate non-specific portal triaditis (8.51%). Among children < 12 years, most common diagnoses included unremarkable liver parenchyma, ACR and ischemia/reper fusion injury.Conclusion. 1. Alcohol- and hepatitis- virus related ESCLD, and biliary atresia are leading indications for liver transplantation in adults and children, respectively. 2. Prevalence of 4.28% of moderate steatosis, is much lower than that documented in western literature. Only 5 cases of incidental granulomas is unexpectedly low in a country endemic for tuberculosis. 3. Most common diagnoses of post-transplant liver biopsies in adults has been acute rejection, which is similar to the findings from much larger published series.

FRI-036 - Long-term post-transplant liver biopsies of children: central perivenulitis is associated with circulating donor-specific antibodies and tissue C4D deposition

FRI-036 - Long-term post-transplant liver biopsies of children: central perivenulitis is associated with circulating donor-specific antibodies and tissue C4D deposition

Post-Transplant Natural Antibodies Associate with Kidney Allograft Injury and Reduced Long-Term Survival.

Background The development of antibodies specific to HLA expressed on donor tissue (donor-specific antibodies [DSAs]) is a prominent risk factor for kidney graft loss. Non-HLA antibodies with pathogenic potential have also been described, including natural antibodies (Nabs). These IgG Nabs bind to immunogenic self-determinants, including oxidation-related antigens.Methods To examine the relationship of Nabs with graft outcomes, we assessed Nabs in blinded serum specimens collected from a retrospective cohort of 635 patients who received a transplant between 2005 and 2010 at Necker Hospital in Paris, France. Serum samples were obtained immediately before transplant and at the time of biopsy-proven rejection within the first year or 1 year after transplant. Nabs were detected by ELISA through reactivity to the generic oxidized epitope malondialdehyde.Results Univariate Cox regression analysis identified the development of post-transplant Nabs (defined as 50% increase in reactivity to malondialdehyde) as a significant risk factor for graft loss (hazard ratio, 2.68; 95% confidence interval, 1.49 to 4.82; P=0.001). Post-transplant Nabs also correlated with increased mean Banff scores for histologic signs of graft injury in post-transplant biopsy specimens. Multivariable Cox analyses confirmed Nabs development as a risk factor independent from anti-HLA DSAs (hazard ratio, 2.07; 95% confidence interval, 1.03 to 4.17; P=0.04). Moreover, patients with Nabs and DSAs had a further increased risk of kidney graft loss.Conclusions These findings reveal an association between Nabs, kidney graft injury, and eventual graft failure, suggesting the involvement of Nabs in immune mechanisms of rejection.

Recurrent IgA nephropathy after renal transplantation and steroid withdrawal.

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis; the reported recurrence rate of IgAN after renal transplantation is as high as 13%-50%. The impact of immunosuppressive therapy and steroid withdrawal on the risk of recurrence of IgAN is still under debate. We performed a retrospective single-center study, selecting 123 kidney transplants (rtx) in 120 patients, between January 1995 and December 2012, with IgAN on the native kidney. In 51 of 123 transplants, at least one post-transplantation biopsy for clinical indication was performed; in 28 of 51 transplants, IgAN recurrence (IgANr) was demonstrated. This group (G1; N=28) was compared with a group without IgANr (G2; N=23). In our study, clinically evident IgANr rate was 54.9% (28/51) on biopsied patients. At discharge, the use of the immunosuppressant drugs (tacrolimus, cyclosporine A, mycophenolate mofetil, azathioprine, mTor inhibitors) was not associated with an increased risk of IgANr (P=NS). At discharge, all patients were steroid treated. Neither the use of tacrolimus, mycophenolate mofetil, nor mTor inhibitors (mTori) at biopsy time were associated with IgANr. However, IgANr was significantly higher in patients who experienced steroid withdrawal at any post-transplantation time (OR 7.7 P=.03). The median time to recurrence after steroid withdrawal was 59months (min 4.18, max 113.2).

Impending relapse of myelodysplastic syndrome after allogeneic transplant is difficult to diagnose and requires a multi-modal approach

BackgroundThe only potentially curative therapy for myelodysplastic syndrome is allogeneic hematopoietic cell transplant; unfortunately, there is a high relapse rate. The objective of this study was to perform a detailed clinicopathologic study of patients with relapsed myeloid neoplasm following allogeneic hematopoietic cell transplant for myelodysplastic syndrome.MethodsPre-transplant, post-transplant, and relapse bone marrow and peripheral blood morphologic features (including dysplasia) were retrospectively evaluated by study authors. Clinical features and results of cytogenetic analysis and engraftment/chimerism studies were obtained from the medical record.ResultsOur study describes 21 patients with a median time to relapse of 6 months (range 2–82). Ten of the patients relapsed with higher grade disease, including six with overt acute myeloid leukemia. Pre-transplant megakaryocyte dysplasia was associated with dysplastic megakaryocytes in the relapse specimen; however, neither erythroid dysplasia nor granulocytic dysplasia were associated with their counterpart in the relapse specimen. Relapse specimens had a lower marrow cellularity and higher blast percentage than pre-transplant disease. Cytogenetic comparisons before and after transplant showed variety, including clonal evolution (22%), the same abnormal clone (33%), or a different abnormal clone (22%).ConclusionsOur detailed review of post-transplant marrow biopsies prior to relapse highlights the difficulty in diagnosing relapse and particularly impending relapse.

Negative Correlation Between Hepatitis C Virus (HCV) and Let-7 MicroRNA Family in Transplanted Livers: The Role of rs868 Single-Nucleotide Polymorphism

BackgroundGenetic alterations of TGF-β pathway members, including its transmembrane receptor, TGFBR1, may influence the course of HCV infection. Rs868 is a single-nucleotide polymorphism of the 3′UTR region of TGFBR1, located in a binding site for the conserved let-7/miR98 microRNA family. Previously, we demonstrated a favorable course of hepatitis C recurrence after liver transplantation in rs868 AG genotype of the transplanted liver when compared to rs868 AA. The aim of the present study was to confirm the biological effect of rs868.Material/MethodsHepG2 cell line was transfected with luciferase vectors cloned with 3′UTR of TGFBR1 gene encompassing different rs868 alleles. Post-transplant liver biopsies from 61 patients with HCV-related end-stage liver disease were evaluated histopathologically and analyzed for the expression of TGFBR1 mRNA, let-7/miR98 microRNAs, HCV RNA load, and rs868 genotype.ResultsLuciferase expression was significantly lower in the A allele-containing vector. TGFBR1 mRNA and HCV RNA load were correlated negatively with let-7/miR98 microRNAs and this correlation was significantly stronger for rs868 AG compared to AA genotype. A strong positive correlation was demonstrated between TGFBR1 and HCV in both genotypes. In AG heterozygotes, let-7/miR98 microRNAs showed a strong negative correlation with periportal or periseptal interface hepatitis (Ishak A score).ConclusionsThere is a negative correlation between let-7/miR98 microRNAs and HCV viral load and TGFBR1 mRNA after liver transplantation. In the rs868 AG heterozygotes, this correlation was stronger and there was a negative correlation between let-7/miR98 and Ishak A score, which is in concordance with the previously demonstrated protective role of this genotype in post-transplant hepatitis C recurrence.

Prolonged Delayed Renal Graft Function Secondary to Venous Hypertension.

The case of a 39-year-old highly sensitized woman who underwent second renal transplantation after being on warfarin because of a history of frequent thromboses of her left femoral arteriovenous graft (AVG) is reported here. The patient received a flow cytometric positive crossmatch kidney transplant from a deceased donor. Her posttransplant course was complicated by prolonged delayed graft function (DGF) lasting for 9 months. Antibody-mediated rejection occurred in the immediate postoperative period. This resolved after treatment, and resolution was confirmed by repeat biopsy. Despite this, she had persistent DGF and remained dialysis dependent. A computed tomography scan due to the development of perinephric hematoma after posttransplant biopsy demonstrated venous collateralization around the allograft. At 7 months posttransplant, a venogram during declotting of AVG revealed chronic thrombus in the inferior vena cava (IVC) above the level of native renal veins with a venous gradient of 26 mmHg. After declotting of the graft, iliac venoplasty, and subsequent IVC stent, her renal function continues to improve with a most recent creatinine of 1.4 mg/dL at 36 months posttransplant. Venous hypertension secondary to IVC thrombosis in presence of patent femoral AVG should be considered as a rare cause of prolonged DGF.

Utility of protocol kidney biopsies for de novo donor-specific antibodies.

There is limited information about the role of protocol kidney biopsies for de novo donor-specific antibodies (dnDSA) in kidney transplant recipients, especially in those with stable graft function. We initiated a routine posttransplant DSA monitoring and surveillance biopsy program for dnDSA since 2014. We identified 45 kidney transplant recipients with dnDSA detected between January 2014 and February 2017 who underwent kidney biopsy within 60days of detection of dnDSA. Twenty-nine (64%) had stable graft function and 16 (36%) had impaired graft function at the time of dnDSA detection. Even in the group with stable graft function, we found a high rate of rejection (53%) on biopsy. Eighty-eight percent of patients with impaired graft function had rejection. Those patients with impaired graft function had significantly lower estimated glomerular filtration rate at 12months postbiopsy and at last follow-up. Those with impaired graft function had more graft failures; however, this result was not statistically significant. The high rate of asymptomatic rejection, and the fact that outcomes in asymptomatic patients are poor, is in support of the utility of surveillance biopsies in patients with dnDSA.

EXPRESSION OF THE GROWTH HORMONE SECRETAGOGUE RECEPTOR AND GHRELIN IN HUMAN HEART FAILURE

Heart failure (HF) is defined as occurring when the heart is unable to provide adequate blood flow and oxygen to organs across the body. Currently, a diagnosis of HF is made using a combination of clinical features, cardiac imaging, and detection of certain biomarkers in the circulation, notably BNP. However, a biomarker specific to cardiac tissue and that reflects the heart’s contractile state is lacking. Our group is characterizing the growth hormone secretagogue receptor (GHSR) and its ligand ghrelin as possible cardiac-specific biomarkers for HF. We have previously developed a fluorescent analog of ghrelin, Ghrelin(1-18, Lys18(Cy5), to detect GHSR in cardiac tissue in situ. We hypothesize that GHSR and ghrelin are biomarkers for the early detection of HF. We obtained samples of cardiac tissue from 10 cardiac transplant patients at the time of organ harvesting and serial post-transplant biopsies. Samples from the LV and RA of the explanted hearts, and biopsies from the newly-transplanted hearts (weekly for 4 weeks, monthly for 6 months, and 1 year post-Tx). GHSR levels were measured using Ghrelin(1-18, Lys18(Cy5) and ghrelin and BNP were measured using fluorescent antibodies. All samples were quantified using fluorescence microscopy. Fibrotic tissue was detected using Masson’s trichrome stain. Levels of all markers were compared between the explanted heart and the healthy biopsies using two-tailed t-test, one-way ANOVA and Tukey’s test and Pearson’s correlation (p < 0.05). GHSR and fibrosis levels increased and were highly variable in explanted hearts when compared to the healthy biopsies which had a much lower level of variability. Within 3 individual patients, there were significant differences (p < 0.001, p < 0.05, p < 0.01 respectively) between the explanted heart (LV and RA) and the short-term biopsies of the healthy heart (weeks 1-4) of both GHSR and ghrelin but not BNP. Within the entire transplant patient cohort (n=10), there was a strong positive correlation between both ghrelin and BNP (r2=0.575, p < 0.0001) and ghrelin and GHSR (r2=0.7033, p < 0.0001). GHSR and ghrelin showed elevated expression and significant differences in 3 of the 10 patients with end stage HF where BNP showed no significant differences indicating the increased sensitivity of GHSR and ghrelin in HF detection. Correlation between ghrelin and BNP, and ghrelin and GHSR in cardiac tissue may show evidence of a ghrelin/GHSR system working independently in the myocardium. These results indicate the potential use of ghrelin and GHSR as new cardiac-specific biomarkers that can help with the detection of HF.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

P048 NGS performance on a transplanted liver biopsy sample: A case study

A male pediatric patient was diagnosed with biliary atresia and was transplanted with liver from a deceased donor. The surgery went well, but years later the patient developed antibodies to Cw12, DR14, DQ7 and DQA1∗04:01 and various DP alleles. The need for high resolution typing to determine the identity of de novo DSA and the lack of any remaining pre-transplant sample on a deceased donor led to the use of NGS to determine chimeric typing. Genomic DNA was extracted from a post-transplant liver biopsy from this patient by using Gentra Puregene Tissue kit. We used the Immucor NGS FLEX HLA typing system for amplification and sequencing of HLA genes HLA -A, B, C, DRB1, DRB3/4/5, DQA1, DQB1, DPA1, and DPB1 followed by analysis with MIA FORA software. The NGS methodology is a clonal sequencing approach which solves the phase ambiguity problems inherent with Sanger-based sequencing when alleles are amplified and sequenced together. The genomic DNA extracted from the transplanted liver biopsy is chimeric, with residual recipient DNA at very low but detectable levels. The presence of chimeric reads is the result of co-amplification of both donor and recipient HLA genes. The majority of sequencing reads with zero mismatches belonged to the donor and were concordant with the deceased donor HLA type provided by UNOS. Unclaimed sequencing reads appeared as grey background and derived from the recipient HLA type (previously obtained with pre-transplant samples). In this case and a few other chimeric cases examined in our laboratory, the MIA FORA NGS software detected the HLA type of donor as the called alleles and showed some unclaimed reads that did not align to the donor type but rather to the HLA type of recipient. We note that if the donor and recipient HLA genes are perfectly matched in one or both alleles then they are indistinguishable. The clonal sequencing nature of the NGS reveals PCR primer specificity by identifying the sequences of all co-amplified genomic regions within the intended target region in the same biopsy sample. This case demonstrates the clinical utility of high resolution HLA typing by NGS technology in the clinical setting to de convolute a solid organ biopsy admixture i.e. the ability to do chimeric typing.

Hepatic steatosis after pediatric liver transplant.

Hepatic steatosis develops after liver transplantation (LT) in 30% of adults, and nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in nontransplanted children. However, posttransplant steatosis has been minimally studied in pediatric LT recipients. We explored the prevalence, persistence, and association with chronic liver damage of hepatic steatosis in these children. In this single-center study of pediatric patients transplanted 1988-2015 (n = 318), 31% of those with any posttransplant biopsy (n = 271) had ≥ 1 biopsy with steatosis. Median time from transplant to first biopsy with steatosis was 0.8 months (interquartile range [IQR], 0.3-6.5 months) and to last biopsy with steatosis was 5.5 months (IQR, 1.0-24.5 months); 85% of patients with steatosis also had for-cause biopsies without steatosis. All available for-cause biopsies were re-evaluated (n = 104). Of 9 biopsies that could be interpreted as nonalcoholic steatohepatitis (NASH)/borderline NASH, with steatosis plus inflammation or ballooning, 8 also had features of cholestasis or rejection. Among 70 patients with surveillance biopsies 3.6-20.0 years after transplant, only 1 overweight adolescent had a biopsy with NAFLD (grade 1 steatosis, mild inflammation, no ballooning or fibrosis)-despite a 30% prevalence of overweight/obesity in the cohort and 27% with steatosis on previous for-cause biopsy. Steatosis on preceding for-cause biopsy was not associated with portal (P = 0.49) or perivenular fibrosis (P = 0.85) on surveillance biopsy. Hepatic steatosis commonly develops early after transplant in children and adolescents, but it rarely persists. Biopsies that did have steatosis with NASH characteristics were all for-cause, mostly in patients with NAFLD risk factors and/or confounding causes of liver damage. Prospective studies that follow children into adulthood will be needed to evaluate if and when hepatic steatosis presents a longterm risk for pediatric LT recipients. Liver Transplantation 23 957-967 2017 AASLD.

Retrospective analysis of post-transplant liver biopsies – From diagnosis to therapy – Can we guide further? Experience from a tertiary care center in India

Background and Aim: Post-transplant liver biopsies form a critical part of management of complications arising post-transplant. The objective of this study was to analyze the Indian experience in pathologic diagnosis of liver biopsies after orthotopic liver transplantation (OLT) with special emphasis on cases presenting with intrahepatic cholestasis (IHC). Type, incidence, and timing of major complications were analyzed. All cases with IHC were retrospectively analyzed with clinical inputs to look for cryptic clues in subclassifying such cases. Materials and Methods: Forty-five post-transplant liver biopsies from 39 OLT patients were retrospectively analyzed from May 2015 to May 2016. All biopsies were stained with hematoxylin and eosin and Masson's Trichrome, and other stains were performed as required. Results: The number of liver biopsies performed for each patient ranged from 1 to 3. The timing of these biopsies varied from 5 days to >4 years post-transplant. Of the 39 patients who underwent post-transplant liver biopsies, most common etiology of a liver transplant was hepatitis C virus (HCV)-related chronic liver disease in 66.6% cases. The common complications post-transplant were acute cellular rejection (ACR) (33.3%), biliary stricture (13.3%), HCV recurrence (11.1%), plasma cell hepatitis (4.4%), chronic hepatitis (4.4%), IHC (22.2%), and others. On analysis of post transplant biopsy cases with IHC, we found that patients with high baseline HCV RNA levels had recurrences presenting only with prominent IHC without fibrosis and ballooning of hepatocytes. These changes might represent early stages of fibrosing cholestatic hepatitis (FCH). Conclusions: This study evaluated the types, incidence, and timing of major complications occurring after OLT. ACR remains major complication following transplant. The presence of IHC on biopsy, especially in HCV-positive patients, should prompt anti-HCV therapy even if other features of FCH were not found.

Oval Cells Contribute to Fibrogenesis of Marginal Liver Grafts under Stepwise Regulation of Aldose Reductase and Notch Signaling.

Background and Aims: Expanded donor criteria poses increased risk for late phase complications such as fibrosis that lead to graft dysfunction in liver transplantation. There remains a need to elucidate the precise mechanisms of post-transplant liver damage in order to improve the long-term outcomes of marginal liver grafts. In this study, we aimed to examine the role of oval cells in fibrogenic development of marginal liver grafts and explore the underlying mechanisms.Methods: Using an orthotopic rat liver transplantation model and human post-transplant liver biopsy tissues, the dynamics of oval cells in marginal liver grafts was evaluated by the platform integrating immuno-labeling techniques and ultrastructure examination. Underlying mechanisms were further explored in oval cells and an Aldose reductase (AR) knockout mouse model simulating marginal graft injury.Results: We demonstrated that activation of aldose reductase initiated oval cell proliferation in small-for-size fatty grafts during ductular reaction at the early phase after transplantation. These proliferative oval cells subsequently showed prevailing biliary differentiation and exhibited features of mesenchymal transition including dynamically co-expressing epithelial and mesenchymal markers, developing microstructures for extra-cellular matrix degradation (podosomes) or cell migration (filopodia and blebs), and acquiring the capacity in collagen production. Mechanistic studies further indicated that transition of oval cell-derived biliary cells toward mesenchymal phenotype ensued fibrogenesis in marginal grafts under the regulation of notch signaling pathway.Conclusions: Oval cell activation and their subsequent lineage commitment contribute to post-transplant fibrogenesis of small-for-size fatty liver grafts. Interventions targeting oval cell dynamics may serve as potential strategies to refine current clinical management.

Host conditioning and rejection monitoring in hepatocyte transplantation in humans

Hepatocyte transplantation partially corrects genetic disorders and has been associated anecdotally with reversal of acute liver failure. Monitoring for graft function and rejection has been difficult, and has contributed to limited graft survival. Here we aimed to use preparative liver-directed radiation therapy, and continuous monitoring for possible rejection in an attempt to overcome these limitations. Preparative hepatic irradiation was examined in non-human primates as a strategy to improve engraftment of donor hepatocytes, and was then applied in human subjects. T cell immune monitoring was also examined in human subjects to assess adequacy of immunosuppression. Porcine hepatocyte transplants engrafted and expanded to comprise up to 15% of irradiated segments in immunosuppressed monkeys preconditioned with 10Gy liver-directed irradiation. Two patients with urea cycle deficiencies had early graft loss following hepatocyte transplantation; retrospective immune monitoring suggested the need for additional immunosuppression. Preparative radiation, anti-lymphocyte induction, and frequent immune monitoring were instituted for hepatocyte transplantation in a 27year old female with classical phenylketonuria. Post-transplant liver biopsies demonstrated multiple small clusters of transplanted cells, multiple mitoses, and Ki67+ hepatocytes. Mean peripheral blood phenylalanine (PHE) level fell from pre-transplant levels of 1343±48μM (normal 30-119μM) to 854±25μM (treatment goal ≤360μM) after transplant (36% decrease; p<0.0001), despite transplantation of only half the target number of donor hepatocytes. PHE levels remained below 900μM during supervised follow-up, but graft loss occurred after follow-up became inconsistent. Radiation preconditioning and serial rejection risk assessment may produce better engraftment and long-term survival of transplanted hepatocytes. Hepatocyte xenografts engraft for a period of months in non-human primates and may provide effective therapy for patients with acute liver failure. Hepatocyte transplantation can potentially be used to treat genetic liver disorders but its application in clinical practice has been impeded by inefficient hepatocyte engraftment and the inability to monitor rejection of transplanted liver cells. In this study, we first show in non-human primates that pretreatment of the host liver with radiation improves the engraftment of transplanted liver cells. We then used this knowledge in a series of clinical hepatocyte transplants in patients with genetic liver disorders to show that radiation pretreatment and rejection risk monitoring are safe and, if optimized, could improve engraftment and long-term survival of transplanted hepatocytes in patients.