Banff 2022 Liver Group Meeting report: Monitoring long-term allograft health.

The Banff Working Group on Liver Allograft Pathology met in September 2022. Participants included hepatologists, surgeons, pathologists, immunologists, and histocompatibility specialists. Presentations and discussions focused on the evaluation of long-term allograft health, including noninvasive and tissue monitoring, immunosuppression optimization, and long-term structural changes. Potential revision of the rejection classification scheme to better accommodate and communicate late T cell-mediated rejection patterns and related structural changes, such as nodular regenerative hyperplasia, were discussed. Improved stratification of long-term maintenance immunosuppression to match the heterogeneity of patient settings will be central to improving long-term patient survival. Such personalized therapeutics are in turn contingent on a better understanding and monitoring of allograft status within a rational decision-making approach, likely to be facilitated in implementation with emerging decision-support tools. Proposed revisions to rejection classification emerging from the meeting include the incorporation of interface hepatitis and fibrosis staging. These will be opened to online testing, modified accordingly, and subject to consensus discussion leading up to the next Banff conference.

Benefit of B7-1 staining and abatacept for treatment-resistant post-transplant focal segmental glomerulosclerosis in a predominantly pediatric cohort: time for a reappraisal.

BACKGROUND: Primary FSGS manifests with nephrotic syndrome and may recur following KT. Failure to respond to conventional therapy after recurrence results in poor outcomes. Evaluation of podocyte B7-1 expression and treatment with abatacept (a B7-1 antagonist) has shown promise but remains controversial. METHODS: From 2012 to 2020, twelve patients developed post-KT FSGS with nephrotic range proteinuria, failed conventional therapy, and were treated with abatacept. Nine/twelve (< 21 years old) experienced recurrent FSGS; three adults developed de novo FSGS, occurring from immediately, up to 8 years after KT. KT biopsies were stained for B7-1. RESULTS: Nine KTRs (75%) responded to abatacept. Seven of nine KTRs were B7-1 positive and responded with improvement/resolution of proteinuria. Two patients with rFSGS without biopsies resolved proteinuria after abatacept. Pre-treatment UPCR was 27.0 ± 20.4 (median 13, range 8-56); follow-up UPCR was 0.8 ± 1.3 (median 0.2, range 0.07-3.9, p < 0.004). Two patients who were B7-1 negative on multiple KT biopsies did not respond to abatacept and lost graft function. One patient developed proteinuria while receiving belatacept, stained B7-1 positive, but did not respond to abatacept. CONCLUSIONS: Podocyte B7-1 staining in biopsies of KTRs with post-transplant FSGS identifies a subset of patients who may benefit from abatacept. A higher resolution version of the Graphical abstract is available as Supplementary information.

Pilot study to determine the safety and feasibility of deceased donor liver natural killer cell infusion to liver transplant recipients with hepatocellular carcinoma.

Liver transplantation (LT) is a viable treatment option for cirrhosis patients with hepatocellular carcinoma (HCC). However, recurrence is the rate-limiting factor of long-term survival. To prevent this, we conducted the phase I study of the adoptive transfer of deceased donor liver-derived natural killer (NK) cells. Liver NK cells were extracted from donor liver graft perfusate and were stimulated in vitro with IL-2. The patient received an intravenous infusion of NK cells 3-5 days after LT. Eighteen LT recipients were treated. There were no severe cell infusion-related adverse events or acute rejection episodes. One patient withdrew from the study because the pathological observation revealed sarcoma instead of HCC. All patients who received this immunotherapy completed the follow-up for at least 2 years without evidence of HCC recurrence (median follow-up, 96 months [range, 17-121 months]). Considering that 9 (52.9%) of the 17 patients pathologically exceeded the Milan criteria, liver NK cell infusion is likely to be useful for preventing HCC recurrence after LT. This is the first-in-human immunotherapy study using deceased donor liver-derived NK cells to prevent HCC recurrence after LT. This treatment was well tolerated and resulted in no HCC recurrence after LT.Clinical trial registration www.clinicaltrials.gov ; NCT01147380; registration date: June 17, 2010.

Human SLE variant NCF1-R90H promotes kidney damage and murine lupus through enhanced Tfh2 responses induced by defective efferocytosis of macrophages.

OBJECTIVES: We previously identified a hypomorphic variant, p.Arg90His (p.R90H) of neutrophil cytosolic factor 1 (NCF1, a regulatory subunit of phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 complex), as an putative causal variant for systemic lupus erythematosus (SLE), and established a knock-in (KI) H90 variant in the C57BL/6 background to study how this variant promotes lupus development. METHODS: Wild type (WT) and KI littermates were assessed for immune profiles and lupus-like features. Disease activity and renal damage of patients with SLE were assessed by systemic lupus erythematosus disease activity index (SLEDAI) and renal items of systemic lupus international collaborating clinics (SLICC), respectively. RESULTS: Compared with WT littermates, 5-week-old homozygous KI mice had reduced oxidative burst, splenomegaly, elevated type I interferon (IFN-I) scores, increased ratios of splenic follicular T helper 2 (Tfh2) to either T follicular regulatory (Tfr) or Tfh1 cells, increased ANA+ follicular, germinal centre and plasma cells without spontaneous kidney disease up to 1 year of age. Pristane treatment exacerbated the immune dysregulation and induced IFN-I-dependent kidney disease in 36-week-old H90 KI female mice. Decreased efferocytosis of macrophages derived from KI mice and patients with homozygous H90 SLE promoted elevated ratios of Tfh2/Tfr and Tfh2/Tfh1 as well as dysregulated humoral responses due to reduced voltage-gated proton channel 1 (Hv1)-dependent acidification of phagosome pH to neutralise the decreased electrogenic effect of the H90 variant, resulting in impaired maturation and phagosome proteolysis, and increased autoantibody production and kidney damage in mice and patients with SLE of multiple ancestries. CONCLUSIONS: A lupus causal variant, NCF1-H90, reduces macrophage efferocytosis, enhances Tfh2 responses and promotes autoantibody production and kidney damage in both mice and patients with SLE.

GSTM1 Deletion Exaggerates Kidney Injury in Experimental Mouse Models and Confers the Protective Effect of Cruciferous Vegetables in Mice and Humans.

BACKGROUND: GSTM1 encodes glutathione S-transferase µ-1 (GSTM1), which belongs to a superfamily of phase 2 antioxidant enzymes. The highly prevalent GSTM1 deletion variant is associated with kidney disease progression in human cohorts: the African American Study of Kidney Disease and Hypertension and the Atherosclerosis Risk in Communities (ARIC) Study. METHODS: We generated a Gstm1 knockout mouse line to study its role in a CKD model (involving subtotal nephrectomy) and a hypertension model (induced by angiotensin II). We examined the effect of intake of cruciferous vegetables and GSTM1 genotypes on kidney disease in mice as well as in human ARIC study participants. We also examined the importance of superoxide in the mediating pathways and of hematopoietic GSTM1 on renal inflammation. RESULTS: Gstm1 knockout mice displayed increased oxidative stress, kidney injury, and inflammation in both models. The central mechanism for kidney injury is likely mediated by oxidative stress, because treatment with Tempol, an superoxide dismutase mimetic, rescued kidney injury in knockout mice without lowering BP. Bone marrow crosstransplantation revealed that Gstm1 deletion in the parenchyma, and not in bone marrow-derived cells, drives renal inflammation. Furthermore, supplementation with cruciferous broccoli powder rich in the precursor to antioxidant-activating sulforaphane significantly ameliorated kidney injury in Gstm1 knockout, but not wild-type mice. Similarly, among humans (ARIC study participants), high consumption of cruciferous vegetables was associated with fewer kidney failure events compared with low consumption, but this association was observed primarily in participants homozygous for the GSTM1 deletion variant. CONCLUSIONS: Our data support a role for the GSTM1 enzyme in the modulation of oxidative stress, inflammation, and protective metabolites in CKD.

Clostridium difficile infection mimics intestinal acute cellular rejection in pediatric multivisceral transplant-A case series.

Clostridium difficile infection (CDI) is the most common health care-associated infection in the United States. Thirty-nine percent of intestinal transplant recipients may develop CDI. Induction of rejection has been reported as a rare event. To our knowledge, this will be the second report of an association between CDI and rejection in the literature. We describe our experience with four pediatric MVT recipients, three of whom on treatment of their CDI alone had resolution of biopsy findings of intestinal ACR. Our patients were males aged 2-5 years old who had their first CDI post-MVT occurring from 2 months to 15 months post-transplant. All first episodes of CDI were treated with a 10-14 day course of metronidazole with one additionally receiving vancomycin. All four recipients had recurrent CDI, and two recipients had septic shock as a manifestation of their CDI. Three recipients had biopsies showing mild rejection during episodes of CDI, and treatment of the CDI resulted in resolution of biopsy findings of rejection. Our case series suggests CDI may mimic ACR on intestinal biopsy. Treatment of rejection during active CDI carries the risk of over-suppression and worsening of CDI. Our experience has taught us that surveillance endoscopy for rejection may be deceiving during an active CDI, and if mild acute rejection is noted during active CDI, treatment of rejection can be safely delayed and potentially avoided.

MYH9 E1841K Mutation Augments Proteinuria and Podocyte Injury and Migration.

Intronic variants of the MYH9 gene that encodes the nonmuscle myosin heavy chain IIA are associated with diabetic nephropathy in European Americans and with sickle cell disease-associated nephropathy. However, the causal functional variants of MYH9 have remained elusive. Rare missense mutations in MYH9 cause macrothrombocytopenia and are occasionally associated with development of nephropathy. The E1841K mutation is among the common MYH9 missense mutations and has been associated with nephropathy in some carriers. To determine the contribution of the E1841K mutation in kidney disease, we studied the effects of the E1841K mutation in mice subjected to high salt or angiotensin II (Ang II) as models of hypertension and in mice subjected to renal mass reduction as a model of CKD. Despite similar levels of BP among wild-type (MYH9+/+ ) mice and mice heterozygous (MYH9+/E1841K ) and homozygous (MYH9E1841K/E1841K ) for the mutation in each model, MYH9E1841K/E1841K mice exhibited mildly increased albuminuria in response to high salt; severe albuminuria, nephrinuria, FSGS, and podocyte foot effacement in Ang II-induced hypertension; and early mortality in the renal mass reduction model. Treatment with candesartan during Ang II-induced hypertension attenuated kidney disease development in MYH9E1841K/E1841K mice. In vitro, isolated primary podocytes from MYH9E1841K/E1841K mice exhibited increased lamellipodia formation and reorganization of F-actin stress fibers. Wound healing assays revealed that MYH9+/+ podocytes had the lowest migration rate, followed by MYH9+/E1841K then MYH9E1841K/E1841K podocytes. In conclusion, the MYH9 E1841K variant alters podocyte cytoskeletal structure and renders podocytes more susceptible to injury after a damaging stimulus.

Podocytes exhibit a specialized protein quality control employing derlin-2 in kidney disease.

Podocytes are terminally differentiated cells of the kidney filtration barrier with a limited proliferative capacity and are the primary glomerular target for various sources of cellular stress. Accordingly, it is particularly important for podocytes to cope with stress efficiently to circumvent cell death and avoid compromising renal function. Improperly folded proteins within the endoplasmic reticulum (ER) are associated with increased cellular injury and cell death. To relieve ER stress, protein quality control mechanisms like ER-associated degradation (ERAD) are initiated. Derlin-2 is an important dislocation channel component in the ERAD pathway, having an indispensable role in clearing misfolded glycoproteins from the ER lumen. With studies linking ER stress to kidney disease, we investigated the role of derlin-2 in the susceptibility of podocytes to injury due to protein misfolding. We show that podocytes employ derlin-2 to mediate the ER quality control system to maintain cellular homeostasis in both mouse and human glomeruli. Patients with focal segmental glomerulosclerosis (FSGS) or diabetic nephropathy (DN) upregulate derlin-2 expression in response to glomerular injury, as do corresponding mouse models. In derlin-2-deficient podocytes, compensatory responses were lost under adriamycin (ADR)-induced ER dysfunction, and severe cellular injury ensued via a caspase-12-dependent pathway. Moreover, derlin-2 overexpression in vitro attenuated ADR-induced podocyte injury. Thus derlin-2 is part of a protein quality control mechanism that can rescue glomerular injury attributable to impaired protein folding pathways in the ER. Induction of derlin-2 expression in vivo may have applications in prevention and treatment of glomerular diseases.

Antibody-mediated rejection implies a poor prognosis in kidney transplantation: Results from a single center.

Two major barriers to achieving long-term graft survival include patient nonadherence in taking the prescribed immunosuppression and antibody-mediated rejection(AMR). We were therefore interested in determining the prognostic impact of developing an AMR component to rejection in a prospective randomized trial of 200 kidney transplant recipients who received dual induction therapy (rATG combined with either daclizumab or alemtuzumab) and planned early corticosteroid withdrawal. With a median follow-up of 96 months post-transplant, 40/200 developed a first BPAR; 9/200 developed a second BPAR. An AMR component to rejection was observed in 70% (28/40) of cases. Percentages having C4d deposition, histopathologic evidence of acute AMR, and presence of DSAs/non-DSAs at the time of first developing the AMR component were 64.3% (18/28), 60.7% (17/28), and 53.6% (15/28), respectively. Development of an AMR component was associated with a significantly higher death-censored graft failure rate following rejection in comparison with the patient state of experiencing BPAR but without developing an AMR component (estimated hazard ratio: 4.52, P = 0.01). The observed percentage developing graft failure following development of an AMR component was 53.6% (15/28) vs only 20.0%(3/15) if it was not observed. Actuarial death-censored graft survival at 60 months following development of an AMR component was 28.3 ± 11.9%. In summary, it appears that more effective AMR prevention/treatment strategies are warranted.

Lower tacrolimus trough levels are associated with subsequently higher acute rejection risk during the first 12 months after kidney transplantation.

The premise that lower TAC trough levels are associated with subsequently higher first BPAR risk during the first 12 mo post-transplant was recently questioned. Using our prospectively followed cohort of 528 adult, primary kidney transplant recipients (pooled across four randomized trials) who received reduced TAC dosing plus an IMPDH inhibitor, TAC trough levels measured at seven time points, 7, 14 days, 1, 2, 3, 6 and 9 months post-transplant, were utilized along with Cox's model to determine the multivariable significance of TAC level(t) (a continuous time-dependent covariate equaling the most recently measured TAC level prior to time t) on the hazard rate of developing first BPAR during the first 12 months post-transplant. The percentage developing BPAR during the first 12 months post-transplant was 10.2% (54/528). In univariable analysis, lower TAC level(t) was associated with a significantly higher BPAR rate (P = 0.00006), and its significance was maintained even after controlling for 2 significant baseline predictors (African-American/Hispanic Recipient and Developed DGF) in Cox's model (multivariable P = 0.0003). Use of a cutpoint, TAC level(t) <4.0 vs. ≥4.0 ng/ml, yielded an even greater association with BPAR rate (univariable and multivariable P < 0.000001), with an estimated hazard ratio of 6.33. These results suggest that TAC levels <4.0 ng/ml should be avoided during the first 12 months post-transplant when TAC is used in combination with fixed-dose mycophenolate with or without corticosteroids and induction therapy.

Intrinsic self-DNA triggers inflammatory disease dependent on STING.

Inflammatory diseases such as Aicardi-Goutières syndrome and severe systemic lupus erythematosus are generally lethal disorders that have been traced to defects in the exonuclease TREX1 (DNase III). Mice lacking TREX1 similarly die at an early age through comparable symptoms, including inflammatory myocarditis, through chronic activation of the stimulator of IFN genes (STING) pathway. In this study, we demonstrate that phagocytes rather than myocytes are predominantly responsible for causing inflammation, an outcome that could be alleviated following adoptive transfer of normal bone marrow into TREX1(-/-) mice. TREX1(-/-) macrophages did not exhibit significant augmented ability to produce proinflammatory cytokines compared with normal macrophages following exposure to STING-dependent activators, but rather appeared chronically stimulated by genomic DNA. These results shed molecular insight into inflammation and provide concepts for the design of new therapies.

Differential efficacy of human mesenchymal stem cells based on source of origin.

Mesenchymal stem cells (MSCs) are useful in tissue repair but also possess immunomodulatory properties. Murine and uncontrolled human trials suggest efficacy of MSCs in treating lupus. Autologous cells are preferable; however, recent studies suggest that lupus-derived MSCs lack efficacy in treating disease. Thus, the optimum derivation of MSCs for use in lupus is unknown. It is also unknown which in vitro assays of MSC function predict in vivo efficacy. The objectives for this study were to provide insight into the optimum source of MSCs and to identify in vitro assays that predict in vivo efficacy. We derived MSCs from four umbilical cords, four healthy bone marrows (BMs), and four lupus BMs. In diseased MRL/lpr mice, MSCs from healthy BM and umbilical cords significantly decreased renal disease, whereas lupus BM MSCs only delayed disease. Current in vitro assays did not differentiate efficacy of the different MSCs. However, differences in MSC efficacy were observed in B cell proliferation assays. Our results suggest that autologous MSCs from lupus patients are not effective in treating disease. Furthermore, standard in vitro assays for MSC licensing are not predictive of in vivo efficacy, whereas inhibiting B cell proliferation appears to differentiate effective MSCs from ineffective MSCs.

Abdominal transplantation for unresectable tumors in children: the zooming out principle.

PURPOSE: To present our experience in abdominal transplantations to manage unresectable abdominal neoplasms in children and to describe the role of extensive surgeries in such cases. METHODS: This is a retrospective study of 22 abdominal transplantations in 21 patients for abdominal tumors over 16 years. Transplantation techniques included liver transplant (LT), multivisceral transplant (MVTx), and intestinal autotransplant (IA). Follow-up intervals ranged from 0.3 to 168 months (median 20 months). RESULTS: LT alone was performed in 15 patients for primary malignant (11) and benign (4) liver tumors. Pathological classification included HB hepatoblastoma (6), HCC hepatocellular cancer (3), hepatic epithelioid hemangioendothelioma HEH (1), angiosarcoma (1), benign vascular tumors (3), and adenoma (1). IA was performed in four patients for lesions involving the root of the mesentery; tumors of the head of pancreas (3) and mesenteric hemangioma (1). MVTx was performed in 2 patients for malignancies; pancreaticoblastoma (1), recurrent hepatoblastoma (1), and in one patient as a rescue procedure after IA failure. Four of the eleven patients who underwent LT for malignant liver tumor had metastatic disease at presentation. Six of them died of recurrent neoplasm (3), transplant-related complications (2), and underlying disease (1). All LT patients who had benign tumors are alive with functioning grafts. All IA patients survived and are on an oral diet, with one patient requiring TPN supplementation. One of the three patients who underwent MVTx died of metastatic disease. CONCLUSIONS: Allo/auto transplantation for abdominal tumors is a valuable modality when conventional treatments fail or are not feasible.

Single-centre study of 628 adult, primary kidney transplant recipients showing no unfavourable effect of new-onset diabetes after transplant.

AIMS/HYPOTHESIS: To better understand the implications of new-onset diabetes after transplant (NODAT), we used our prospectively followed cohort of 628 adult primary kidney transplant recipients to determine the prognostic impact of pretransplant diabetes and NODAT. METHODS: The study cohort consisted of all participants in four randomised immunosuppression trials performed at our centre since May 2000. For each cause-specific hazard analysed, Cox stepwise regression was used to determine a multivariable model of significant baseline predictors; the multivariable influence of having pretransplant diabetes and NODAT (t) (the latter defined as a zero-one, time-dependent covariate) was subsequently tested. Similar analyses of estimated glomerular filtration rate (eGFR) at 36 and 60 months post transplant were performed using stepwise linear regression. Finally, a repeated measures analysis of mean HbA1c as a function of diabetes category (pretransplant diabetes vs NODAT) and randomised trial (first to fourth) was performed. RESULTS: Median follow-up was 56 months post transplant. Patients with pretransplant diabetes comprised 23.4% (147/628), and 22.5% (108/481) of the remaining patients developed NODAT. Pretransplant diabetes had no prognostic influence on first biopsy-proven acute rejection and death-censored graft failure hazard rates, nor on eGFR, but was associated with significantly higher rates of death with a functioning graft (DWFG) (p = 0.003), DWFG due to a cardiovascular event (p = 0.005) and infection that required hospitalisation (p = 0.03). NODAT (t) had no unfavourable impact on any of these hazard rates nor on eGFR, with actuarial freedom from DWFG remaining at over 90% among patients in pre- and post-NODAT states at 72 months post transplant/NODAT. Mean HbA1c for patients in the first to fourth randomised trials, averaged across diabetes category, decreased by trial (7.28%, 6.92%, 6.87% and 6.64% [56.1, 52.1, 51.6 and 49.1 mmol/mol], respectively; p = 0.02). CONCLUSIONS/INTERPRETATION: Less-than-expected post-NODAT risk for graft loss and death may exist in the current climate of tighter glucose monitoring post transplant.

Lessons From Pancreas Transplantation in Type 1 Diabetes: Recurrence of Islet Autoimmunity.

Type 1 diabetes recurrence (T1DR) affecting pancreas transplants was first reported in recipients of living-related pancreas grafts from twins or HLA identical siblings; given HLA identity, recipients received no or minimal immunosuppression. This observation provided critical evidence that type 1 diabetes (T1D) is an autoimmune disease. However, T1DR is traditionally considered very rare in immunosuppressed recipients of pancreas grafts from organ donors, representing the majority of recipients, and immunological graft failures are ascribed to chronic rejection. We have been performing simultaneous pancreas-kidney (SPK) transplants for over 25 years and find that 6-8 % of our recipients develop T1DR, with symptoms usually becoming manifest on extended follow-up. T1DR is typically characterized by (1) variable degree of insulitis and loss of insulin staining, on pancreas transplant biopsy (with most often absent), minimal to moderate and rarely severe pancreas, and/or kidney transplant rejection; (2) the conversion of T1D-associated autoantibodies (to the autoantigens GAD65, IA-2, and ZnT8), preceding hyperglycemia by a variable length of time; and (3) the presence of autoreactive T cells in the peripheral blood, pancreas transplant, and/or peripancreatic transplant lymph nodes. There is no therapeutic regimen that so far has controlled the progression of islet autoimmunity, even when additional immunosuppression was added to the ongoing chronic regimens; we hope that further studies and, in particular, in-depth analysis of pancreas transplant biopsies with recurrent diabetes will help identify more effective therapeutic approaches.

Multivariable risk of developing new onset diabetes after transplant-results from a single-center study of 481 adult, primary kidney transplant recipients.

BACKGROUND: Understanding the relative contributions of baseline demographics and immunosuppressive therapy on NODAT risk may help in developing preventive strategies. METHODS: Using our prospectively followed cohort of 481 adult, primary kidney transplant recipients without pre-transplant diabetes, we determined the significant baseline predictors for the hazard rate of developing NODAT via Cox stepwise regression. The multivariable influence of first BPAR (defined as a time-dependent covariate) was also tested. RESULTS: Median follow-up was 57 mo post-transplant; the overall percentage who developed NODAT was 22.5% (108/481). Four baseline predictors of a greater NODAT hazard rate were found (by order of selection): higher BMI (p < 0.000001), planned maintenance with SRL (p = 0.0003), non-white recipient (p = 0.0004), and older recipient age (p = 0.0004). Approximately one-half of the 106 patients in the highest demographic risk category (BMI ≥25 kg/m(2) , non-white race, and age at transplant ≥40 yr) developed NODAT; actuarial NODAT risk ranged from 10% to 30% in the lower demographic risk categories. First BPAR was also associated with significantly higher NODAT in multivariable analysis (p = 0.02)-the highly elevated NODAT rate observed during the first few months post-transplant and following first BPAR appears to demonstrate the diabetogenic effect of using high-dose (intravenous) corticosteroids. CONCLUSIONS: The disturbingly high NODAT rate found among patients having multiple demographic risk factors is still an important problem that awaits a better solution.

Clinical significance of intragraft miR-122 and -155 expression after liver transplantation.

AIM: Recurrent hepatitis C (RHC) and acute cellular rejection (AR) remain critical problems following liver transplantation (LT) in hepatitis C virus (HCV) positive recipients because of the similar clinical features. Discrimination between these conditions can be problematic, and adjunctive biomarkers would be useful to discriminate these processes. The aim of our study was to investigate the possibility of the intragraft miR-122 and -155 expression as new biomarkers after LT. METHODS: A total of 29 HCV positive recipients were enrolled in this study. Intragraft expressions of miR-122 and -155 were studied between RHC predominant (n = 17) and AR predominant cases (n = 12) using quantitative reverse transcription polymerase chain reaction. Furthermore, we investigated the correlations between these expression levels and clinical serum parameters. RESULTS: Intragraft miR-122 expression had a good correlation with serum alkaline phosphatase (P = 0.02), but it was not correlated with the serum HCV viral load. The expression levels of miR-122 in the AR group were significantly higher than those in the RHC group (P = 0.0006) and, inversely, the expression levels of miR-155 in the AR group were significantly lower than those in the RHC group (P = 0.01). CONCLUSION: Our study emphasizes a useful pattern of miR-122 and -155 as ancillary markers to discriminate AR predominant cases from RHC in HCV positive patients after LT.

Transient receptor potential channel 6 (TRPC6) protects podocytes during complement-mediated glomerular disease.

Gain-of-function mutations in the calcium channel TRPC6 lead to autosomal dominant focal segmental glomerulosclerosis and podocyte expression of TRPC6 is increased in some acquired human glomerular diseases, particularly in membranous nephropathy. These observations led to the hypothesis that TRPC6 overactivation is deleterious to podocytes through pathological calcium signaling, both in genetic and acquired diseases. Here, we show that the effects of TRPC6 on podocyte function are context-dependent. Overexpression of TRPC6 alone did not directly affect podocyte morphology and cytoskeletal structure. Unexpectedly, however, overexpression of TRPC6 protected podocytes from complement-mediated injury, whereas genetic or pharmacological TRPC6 inactivation increased podocyte susceptibility to complement. Mechanistically, this effect was mediated by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) activation. Podocyte-specific TRPC6 transgenic mice showed stronger CaMKII activation, reduced podocyte foot process effacement and reduced levels of proteinuria during nephrotoxic serum nephritis, whereas TRPC6 null mice exhibited reduced CaMKII activation and higher levels of proteinuria compared with wild type littermates. Human membranous nephropathy biopsy samples showed podocyte staining for active CaMKII, which correlated with the degree of TRPC6 expression. Together, these data suggest a dual and context dependent role of TRPC6 in podocytes where acute activation protects from complement-mediated damage, but chronic overactivation leads to focal segmental glomerulosclerosis.

When and why portal vein thrombosis matters in liver transplantation: a critical audit of 174 cases.

OBJECTIVE: To identify complications associated with different techniques utilized to treat portal vein thrombosis (PVT) during primary liver transplantation and their impact on survival. BACKGROUND: PVT remains an intricate problem in liver transplantation, and the long-term outcomes of patients with PVT who undergo transplantation are not well defined. METHODS: We performed a retrospective cohort analysis of all consecutive adult patients who underwent primary isolated liver transplantation from 1998 to 2009 (median follow-up period, 89 months). The outcomes of patients with PVT were compared with those without PVT. RESULTS: Among 1379 recipients, 174 (12.6%) had PVT at the time of transplantation [83 (48%) complete and 91 (52%) partial]. Among PVT patients with reestablished physiological portal inflow (PVT: physiological group; n = 149), 123 underwent thrombectomies, 16 received interpositional vein grafts, and 10 received mesoportal jump grafts. In 25 patients, physiological portomesenteric venous circulation was not reconstituted (PVT: nonphysiological group; 18 underwent cavoportal hemitranspositions, 6 renoportal anastomoses, and 1 arterialization). The PVT: nonphysiological group suffered a significantly increased incidence of rethrombosis of the portomesenteric veins and gastrointestinal bleeding, with a marginal 10-year overall survival rate of 42% (no PVT, 61%; P = 0.002 and PVT: physiological, 55%; P = 0.043). The PVT: physiological and no PVT groups exhibited comparable survival rates (P = 0.13). No significant differences in survival were observed between complete and partial PVT as long as physiological portal flow was reestablished. CONCLUSIONS: The subset of PVT patients requiring nonphysiological portal vein reconstruction was associated with higher complication rates and suffered diminished long-term prognoses. For the most severe PVT cases, a comprehensive approach is critical to further improve outcomes.