Protein Signatures of Remodeled Airways in Transplanted Lungs with Bronchiolitis Obliterans Syndrome Obtained Using Laser-Capture Microdissection.

Bronchiolitis obliterans syndrome, a common form of chronic lung allograft dysfunction, is the major limitation to long-term survival after lung transplantation. The histologic correlate is progressive, fibrotic occlusion of small airways, obliterative bronchiolitis lesions, which ultimately lead to organ failure. The molecular composition of these lesions is unknown. In this sutdy, the protein composition of the lesions in explanted lungs from four end-stage bronchiolitis obliterans syndrome patients was analyzed using laser-capture microdissection and optimized sample preparation protocols for mass spectrometry. Immunohistochemistry and immunofluorescence were used to determine the spatial distribution of commonly identified proteins on the tissue level, and protein signatures for 14 obliterative bronchiolitis lesions were established. A set of 39 proteins, identified in >75% of lesions, included distinct structural proteins (collagen types IV and VI) and cellular components (actins, vimentin, and tryptase). Each respective lesion exhibited a unique composition of proteins (on average, n = 66 proteins), thereby mirroring the morphologic variation of the lesions. Antibody-based staining confirmed these mass spectrometry-based findings. The 14 analyzed obliterative bronchiolitis lesions showed variations in their protein content, but also common features. This study provides molecular and morphologic insights into the development of chronic rejection after lung transplantation. The protein patterns in the lesions were correlated to pathways of extracellular matrix organization, tissue development, and wound healing processes.

Differential IgG4-Producing Plasma Cell Infiltration in Non- and Post-Transplant Plasma Cell Hepatitis.

Autoimmune hepatitis (AIH), post-transplant recurrent AIH (rAIH), and plasma cell-rich rejection (PCR) are clinical diagnoses with the shared histopathologic hallmark of plasma cell hepatitis (PCH). As these histologically and serologically indistinguishable diagnoses are differentiated by clinical context, it remains uncertain whether they represent distinct immunologic phenomena. Improved understanding of immunoglobulin subclass 4-producing plasma cells (IgG4-PC) has brought attention to IgG4 as an immunophenotypic biomarker. To date, degree and clinical significance of IgG4-PC infiltration in PCH remain elusive. This retrospective, single-center study assessed IgG4-PC infiltration in AIH, rAIH, and PCR via standardized immunohistochemistry analysis. Identified cases from 2005 to 2020 (n = 47) included AIH (treatment-naïve AIH (tnAIH): n = 15 and AIH-flare on treatment (fAIH); n = 10), rAIH (n = 8), and PCR (n = 14) were analyzed and correlated with clinical characteristics. IgG4-Positivity (# IgG4-PC/# pan-IgG-expressing cells) distribution was heterogenous and overlapping [tnAIH: 0.060 (IQR 0.040-0.079), fAIH: 0.000 (0.000-0.033), rAIH: 0.000 (0.000-0.035), PCR: 0.228 (0.039-0.558)]. IgG4-Positivity was inversely correlated with corticosteroid use (p < 0.001). IgG4-Positivity ≥0.500 was associated with rapid AST improvement (p = 0.03). The variable IgG4-Positivity of AIH, rAIH and PCR suggests diverse and overlapping immunopathologic mechanisms and that current diagnostic schemes inadequately capture PCH immunopathology. We propose incorporation of IgG4-Positivity to refine current PCH classification and treatment strategies.

Donor-Specific Antibody Is Associated with Increased Expression of Rejection Transcripts in Renal Transplant Biopsies Classified as No Rejection.

BACKGROUND: Donor -specific HLA antibody (DSA) is present in many kidney transplant patients whose biopsies are classified as no rejection (NR). We explored whether in some NR kidneys DSA has subtle effects not currently being recognized. METHODS: We used microarrays to examine the relationship between standard-of-care DSA and rejection-related transcript increases in 1679 kidney transplant indication biopsies in the INTERCOMEX study (ClinicalTrials.gov NCT01299168), focusing on biopsies classified as NR by automatically assigned archetypal clustering. DSA testing results were available for 835 NR biopsies and were positive in 271 (32%). RESULTS: DSA positivity in NR biopsies was associated with mildly increased expression of antibody-mediated rejection (ABMR)-related transcripts, particularly IFNG-inducible and NK cell transcripts. We developed a machine learning DSA probability (DSAProb) classifier based on transcript expression in biopsies from DSA-positive versus DSA-negative patients, assigning scores using 10-fold cross-validation. This DSAProb classifier was very similar to a previously described "ABMR probability" classifier trained on histologic ABMR in transcript associations and prediction of molecular or histologic ABMR. Plotting the biopsies using Uniform Manifold Approximation and Projection revealed a gradient of increasing molecular ABMR-like transcript expression in NR biopsies, associated with increased DSA (P<2 × 10-16). In biopsies with no molecular or histologic rejection, increased DSAProb or ABMR probability scores were associated with increased risk of kidney failure over 3 years. CONCLUSIONS: Many biopsies currently considered to have no molecular or histologic rejection have mild increases in expression of ABMR-related transcripts, associated with increasing frequency of DSA. Thus, mild molecular ABMR-related pathology is more common than previously realized.

The clinical significance of receiving a kidney allograft from deceased donor with chronic histologic changes.

Allograft survival of deceased donor kidneys with suboptimal histology (DRTx/suboptimal histology: >10% glomerulosclerosis, >10% tubulointerstitial scarring, or >mild vascular sclerosis) is inferior to both DRTx with optimal histology (DRTx/optimal histology) and living donor kidneys irrespective of histologic changes (LRTx). In this report, we explored the reasons behind this guarded outcome with a special focus on the role of alloimmunity. We initially assessed gene expression in 39 time-zero allograft biopsies using the Nanostring 770 genes PanCancer Immune Profiling Panel. Subsequently, we studied 696 consecutive adult kidney allograft recipients that were grouped according to allograft type and histology at time-zero biopsy [DRTx/suboptimal histology (n = 194), DRTx/optimal histology (n = 166), and LRTx (n = 336)]. Part-1: Several immune pathways were upregulated in time-zero biopsies from DRTx/suboptimal histology (n = 11) compared to LRTx (n = 17) but not to DRTx/optimal histology (n = 11). Part-2: Amongst the three groups of recipients, DRTx/suboptimal histology had the highest incidence of acute rejection episodes, most of which occurred during the first year after transplantation (early rejection). This increase was mainly attributed to T cell mediated rejection, while the incidence of antibody-mediated rejection was similar amongst the three groups. Importantly, early acute T cell mediated rejection was a strong independent predictor for allograft failure in DRTx/suboptimal histology (adjusted HR: 2.13, P = 0.005) but not in DRTx/optimal histology nor in LRTx. Our data highlight an increased baseline immunogenicity in DRTx/suboptimal histology compared to LRTx but not to DRTx/optimal histology. However, our results suggest that donor chronic histologic changes in DRTx may help transfer such increased baseline immunogenicity into clinically relevant acute rejection episodes that have detrimental effects on allograft survival. These findings may provide a rationale for enhanced immunosuppression in recipients of DRTx with baseline chronic histologic changes to minimize subsequent acute rejection and to prolong allograft survival.

Detection of Bleeding Complications After Renal Transplant Biopsy.

OBJECTIVE. The purpose of this study was to analyze the timing of major bleeding complications after renal transplant biopsy in the context of a standardized 1-hour postprocedure observation protocol. MATERIALS AND METHODS. We retrospectively reviewed the electronic medical records for consecutive patients who underwent ultrasound-guided renal transplant biopsies between January 1, 2012, and December 31, 2017, and were observed according to a newly implemented 1-hour postprocedure observation protocol. The development of a major bleeding complication (Common Terminology Criteria for Adverse Events class 3 or higher) was recorded along with all available details regarding the time course of patient symptoms and presentation. Complications were grouped into one of four categories according to onset time after biopsy: 2 hours or less (timing category 1), more than 2 hours but 4 hours or less (timing category 2), more than 4 hours but 8 hours or less (timing category 3), and more than 8 hours (timing category 4). RESULTS. In 1824 patients (769 women, 1055 men) who underwent 4519 consecutive ultrasound-guided renal transplant biopsies during the study period, 11 class 3 complications were found (11/4519 [0.2%]). Four of the 11 patients (36.4%) had symptoms during the 1-hour observation period. Of these four patients, three (3/11 [27.3%]) had substantial symptoms related to major bleeding and were classified as timing category 1, and one (1/11 [9.1%]) had initially minor symptoms that increased in severity more than 2 hours but within 4 hours and was classified as timing category 2. Seven of the 11 patients (63.6%) did not have any symptoms at 1 hour of observation and were discharged; three (27.3%) were classified as timing category 3, and four (36.4%) were classified as category 4. CONCLUSION. Major bleeding complications following ultrasound-guided renal transplant biopsy are rare (0.2% of patients in this study). In our study, more than half were not clinically apparent within 4 hours of biopsy. A 1-hour postprocedure recovery period can be safely used after renal transplant biopsy.

Liver regeneration after performing associating liver partition and portal vein occlusion for staged hepatectomy (ALPPS) is histologically similar to that occurring after liver transplantation using a small-for-size graft.

PURPOSE: Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) can achieve marked future liver remnant (FLR) hypertrophy but this procedure is associated with a risk of mortality due to liver failure because of an insufficient FLR functional increase, a situation comparable to small-for-size syndrome (SFSS) after living-donor liver transplantation (LDLT). METHODS: The clinical data, morphologic volume changes, and histopathologic and immunohistochemical findings in hepatocytes and bile ductules were compared between ALPPS (n = 10) and LDLT with a risk for SFSS (n = 12). RESULTS: Although the patient characteristics and short-term outcome differed between the groups, the mean hypertrophy ratios with respect to liver volume for the FLR after performing the first-stage ALPPS procedures resembled those in small-for-size grafts after similar time intervals: 1.702 ± 0.407 in ALPPS vs. 1.948 ± 0.252 in LDLT (P = 0.205). The histologic grades for sinusoidal dilation (P = 0.896), congestion (P = 0.922), vacuolar change (P = 0.964), hepatocanalicular cholestasis (P = 0.969), and ductular reaction (P = 0.728) within the FLR at the second-stage operation during ALPPS or implanted graft were all similar between the groups. CONCLUSIONS: The hepatic regenerative process may be similar in ALPPS and LDLT using a small-for-size graft. Reducing the hepatic vascular inflow that may be excessive for the FLR volume during the first stage of ALPPS might enhance the functional recovery since measures with a similar effect appear to lessen the likelihood of SFSS.

Management of Renal Cell Carcinoma and Other Renal Masses in the Kidney Graft.

PURPOSE OF REVIEW: Renal masses in the kidney graft pose an important clinical dilemma, balancing graft function against the need for cancer control. RECENT FINDINGS: Donor origin cancers in the renal graft can be classified as 'donor transmitted' or 'donor derived'. The landmark TracerX Renal changed our understanding of renal cell carcinoma oncogenesis, demonstrating that key mutations in childhood lead to clinically apparent tumours in later life. Identified pre-operatively, contemporary evidence suggests that masses excised prior to transplantation result in acceptable oncologic safety and graft function. Identified post-operatively management mirrors that for a mass in a solitary kidney in the non-transplant population, with focus on a nephron-sparing approach. With growing number of kidney transplants each year, ageing donors, and increasing graft survival, masses in the renal graft are likely to become a more prevalent clinical conundrum.

Microvascular inflammation is a risk factor in kidney transplant recipients with very late conversion from calcineurin inhibitor-based regimens to belatacept.

BACKGROUND: In de novo kidney transplant recipients (KTR) treatment with belatacept has been established as a comparable option as maintenance immunosuppression, preferably as a strategy to convert from calcineurin inhibitor (CNI)- to belatacept-based immunosuppression. Switch to belatacept demonstrated improved renal function in patients with CNI-induced nephrotoxicity, but risk of transplant rejection and the development of donor-specific antibodies (DSA) are still a matter of debate. Only few data are available in patients at increased immunological risk and late after transplantation. METHODS: We analyzed 30 long-term KTR (including 2 combined pancreas-KTR) converted from CNI to belatacept > 60 months after transplantation with moderate to severe graft dysfunction (GFR ≤ 45 mL/min). Biopsies were classified according to the Banff 2015 criteria. Group differences were assessed in a univariate analysis using Mann Whitney U or Chi square test, respectively. Multivariate analysis of risk factors for treatment failure was performed using a binary logistic regression model including significant predictors from univariate analysis. Fifty-six KTR matched for donor and recipient characteristics were used as a control cohort remaining under CNI-treatment. RESULTS: Patient survival in belatacept cohort at 12/24 months was 96.7%/90%, overall graft survival was 76.7 and 60.0%, while graft survival censored for death was 79.3%/66.7%. In patients with functioning grafts, median GFR improved from 22.5 mL/min to 24.5 mL/min at 24 months. Positivity for DSA at conversion was 46.7%. From univariate analysis of risk factors for graft loss, GFR < 25 mL/min (p = 0.042) and Banff microvascular inflammation (MVI) sum score ≥ 2 (p = 0.023) at conversion were significant at 24 months. In the analysis of risk factors for treatment failure, a MVI sum score ≥ 2 was significant univariately (p = 0.023) and in a bivariate (p = 0.037) logistic regression at 12 months. DSA-positivity was neither associated with graft loss nor treatment failure. The control cohort had comparable graft survival outcomes at 24 months, albeit without increase of mean GFR in patients with functioning grafts (ΔGFR of - 3.6 ± 8.5 mL/min). CONCLUSION: Rescue therapy with conversion to belatacept is feasible in patients with worsening renal function, even many years after transplantation. The benefit in patients with MVI and severe GFR impairment remains to be investigated.

Increased CD200 expression in post-transplant lymphoproliferative disorders correlates with an increased frequency of FoxP3(+) regulatory T cells.

CD200 is a membrane protein with immunosuppressive function and is expressed in many hematopoietic neoplasms, including acute myeloid leukemia (AML), plasma cell myeloma (PCM), and B-cell lymphoproliferative disorders, but is mostly negative in diffuse large cell lymphoma (DLBCL). CD200 has been shown to be a poor prognostic marker in AML and PCM; in AML, its immunomodulatory effect was linked to its ability to induce FoxP3(+) regulatory T cells (Tregs). Post-transplant lymphoproliferative disorders (PTLDs) arise in the setting of immune dysregulation, and tumor-infiltrating T cells, including Tregs, have been shown to correlate with outcome in these disorders. Because there is no literature data and CD200 is a potentially useful diagnostic and prognostic marker, we studied the expression of CD200 in a series of 38 PTLDs by immunohistochemistry (ICH), and found that 23.7% PTLDs were CD200(+) and showed strong membrane and cytoplasmic positivity in the neoplastic cells. All CD200(+) monomorphic PTLDs were DLBCLs and the median FoxP3(+) Treg count/hpf was higher in CD200(+) than in CD200(-) PTLDs: 22.6 vs. 0.30 (p < 0.001). These results indicated that almost a quarter of PTLDs in our series are CD200(+) by IHC, and CD200 expression correlates with the frequency of immunosuppressive Tregs. This is novel data and supports a pathophysiologic link between CD200 activity and Tregs. In our series, the 5-year overall survival was shorter in CD200(+) PTLDs, compared to CD200(-) patients, although this difference did not reach statistical significance. In addition, we find a higher proportion of CD200(+) monomorphic PTLD-DLBCLs (31.0%), as compared to de novo DLBCLs (7-8%, as found here and in other studies). This may indicate differential expression of CD200 in B-cell lymphomas arising in the setting of immune dysregulation, and raises the possibility of anti-CD200 immunotherapy for these cases.

Macrophage Proinflammatory Responses to Microorganisms and Transplanted Organs.

Tissue-resident macrophages and those conscripted from the blood/bone marrow are professional phagocytes. They play a role in tissue homeostasis, replacement, and healing, and are the first-line responders to microbial (viral, bacterial, and fungi) infections. Intrinsic ameboid-type motility allows non-resident macrophages to move to the site of inflammation or injury, where, in response to the inflammatory milieu they perform the anti-microbial and/or tissue repair functions. Depending on the need and the signaling from the surrounding tissue and other immune cells, macrophages acquire morphologically and functionally different phenotypes, which allow them to play either pro-inflammatory or anti-inflammatory functions. As such, the macrophages are also the major players in the rejection of the transplanted organs making an excellent target for the novel anti-rejection therapies in clinical transplantation. In this review, we describe some of the less covered aspects of macrophage response to microbial infection and organ transplantation.

Precision transplant pathology.

PURPOSE OF REVIEW: Transplant pathology contributes substantially to personalized treatment of organ allograft recipients. Rapidly advancing next-generation human leukocyte antigen (HLA) sequencing and pathology are enhancing the abilities to improve donor/recipient matching and allograft monitoring. RECENT FINDINGS: The present review summarizes the workflow of a prototypical patient through a pathology practice, highlighting histocompatibility assessment and pathologic review of tissues as areas that are evolving to incorporate next-generation technologies while emphasizing critical needs of the field. SUMMARY: Successful organ transplantation starts with the most precise pratical donor-recipient histocompatibility matching. Next-generation sequencing provides the highest resolution donor-recipient matching and enables eplet mismatch scores and more precise monitoring of donor-specific antibodies (DSAs) that may arise after transplant. Multiplex labeling combined with hand-crafted machine learning is transforming traditional histopathology. The combination of traditional blood/body fluid laboratory tests, eplet and DSA analysis, traditional and next-generation histopathology, and -omics-based platforms enables risk stratification and identification of early subclinical molecular-based changes that precede a decline in allograft function. Needs include software integration of data derived from diverse platforms that can render the most accurate assessment of allograft health and needs for immunosuppression adjustments.

Dedicator of cytokinesis 2 silencing therapy inhibits neointima formation and improves blood flow in rat vein grafts.

OBJECTIVE: The high rate of vein graft failure due to neointimal hyperplasia is a major challenge for cardiovascular surgery. Finding novel approaches to prevent neointimal hyperplasia is important. Thus, the purpose of this study was to investigate whether dedicator of cytokinesis 2 (DOCK2) plays a role in the development of neointima formation in the vein grafts. METHODS AND RESULTS: We found that DOCK2 levels were significantly elevated in the vein grafts following grafting surgery. In addition, overexpression of DOCK2 promoted venous smooth muscle cell (SMC) proliferation and migration. Conversely, knocking-down endogenous DOCK2 expression in venous SMCs inhibited SMC proliferation and migration. Consistent with this, knocking-down DOCK2 expression in the grafted veins significantly reduced neointimal formation compared with the controls 28 days after vein transplantation. Moreover, DOCK2 silencing treatment improved hemodynamics in the vein grafts. Mechanistically, knockdown of DOCK2 significantly alleviated the vein graft-induced down regulation of SMC contractile protein expression and impeded the vein graft-induction of both Cyclin D1 and PCNA expression. In particular, to ensure high efficiency when transferring the DOCK2 short hairpin RNA (shDOCK2) into the grafted veins, a 30% poloxamer F-127 gel incorporated with 0.25% trypsin was smeared around the vein grafts to increase the adenovirus contact time and penetration. CONCLUSIONS: DOCK2 silencing gene therapy effectively attenuates neointimal hyperplasia in vein grafts. Knock-down of DOCK2 would be a potential therapeutic approach for the treatment of vein graft failure.

Impact of acute kidney injury in expanded criteria deceased donors on post-transplant clinical outcomes: multicenter cohort study.

BACKGROUND: The problem of organ shortage is an important issue in kidney transplantation, but the effect of kidney donation on AKI is unclear. The aim of this study was to investigate the impact of acute kidney injury (AKI) on post-transplant clinical outcomes for deceased donor kidney transplantation (DDKT) using standard criteria donors (SCDs) versus expanded criteria donors (ECDs). METHODS: Five-hundred nine KT recipients receiving kidneys from 386 deceased donors (DDs) were included from three transplant centers. Recipients were classified into the SCD-KT or ECD-KT group according to corresponding DDs and both groups were divided into the AKI-KT or non-AKI-KT subgroups according to AKI in donor. We compared the clinical outcomes among those four groups and investigated the interaction between AKI in donors and ECD on allograft outcome. RESULTS: The incidence of delayed allograft function was higher when the donors had AKI within SCD-KT and ECD-KT groups. In allograft biopsies within 3 months, chronic change was more significant in the AKI-ECD-KT subgroup than in the non-AKI-ECD-KT subgroup, but it did not differ between AKI-SCD-KT and non-AKI-SCD-KT group. AKI-ECD-KT showed higher risk for death-censored allograft failure than the other three groups and a significant interaction was observed between AKI in donors and ECD on the allograft outcome. CONCLUSIONS: The presence of AKI in ECDs significantly impacted the long-term allograft outcomes of kidney transplant recipients, but it did not in SCDs.

Renal vascular resistance is increased in patients with kidney transplant.

BACKGROUND: Despite improvement in short-term outcome of kidney transplants, the long-term survival of kidney transplants has not changed over past decades. Kidney biopsy is the gold standard of transplant pathology but it's invasive. Quantification of transplant blood flow could provide a novel non-invasive method to evaluate transplant pathology. The aim of this retrospective cross-sectional pilot study was to evaluate positron emission tomography (PET) as a method to measure kidney transplant perfusion and find out if there is correlation between transplant perfusion and histopathology. METHODS: Renal cortical perfusion of 19 kidney transplantation patients [average time from transplantation 33 (17-54) months; eGFR 55 (47-69) ml/min] and 10 healthy controls were studied by [15 O]H2O PET. Perfusion and Doppler resistance index (RI) of transplants were compared with histology of one-year protocol transplant biopsy. RESULTS: Renal cortical perfusion of healthy control subjects and transplant patients were 2.7 (2.4-4.0) ml min- 1 g- 1 and 2.2 (2.0-3.0) ml min- 1 g- 1, respectively (p = 0.1). Renal vascular resistance (RVR) of the patients was 47.0 (36.7-51.4) mmHg mL- 1min- 1g- 1 and that of the healthy 32.4 (24.6-39.6) mmHg mL- 1min-1g-1 (p = 0.01). There was a statistically significant correlation between Doppler RI and perfusion of transplants (r = - 0.51, p = 0.026). Transplant Doppler RI of the group of mild fibrotic changes [0.73 (0.70-0.76)] and the group of no fibrotic changes [0.66 (0.61-0.72)] differed statistically significantly (p = 0.03). No statistically significant correlation was found between cortical perfusion and fibrosis of transplants (p = 0.56). CONCLUSIONS: [15 O]H2O PET showed its capability as a method in measuring perfusion of kidney transplants. RVR of transplant patients with stage 2-3 chronic kidney disease was higher than that of the healthy, although kidney perfusion values didn't differ between the groups. Doppler based RI correlated with perfusion and fibrosis of transplants.

Treatment of Large Scars in Children Using Artificial Dermis and Scalp Skin Grafting.

BACKGROUND AND OBJECTIVES: Large scars formed after burns injury can seriously hamper appearance and function in children. Surgical resection of scars and secondary skin or flap grafting often brings severe damages to donor sites, which may lead to physiological and psychological development disorders in children. Here, we introduce the use of artificial dermis and skin grafts from scalps to treat large scars in children to minimize the donor site morbidity. METHODS: A retrospective char review was performed including 7 children with large scars between January 2016 and December 2017. First, the scars were resected, and artificial dermis was applied to the secondary wounds. Twelve days later, outer silicone membrane was removed. Another 2 days later, scalp skin grafts of 0.3 mm were transplanted to the wounds. Manchester Scar Scale and Visual Analog Scale were used to evaluate scar appearance before and after the treatment respectively. One special patient with extensive scars was treated twice at an interval of 1 year. The first therapy was performed with both conventional method of resection and skin grafting and the new method described above. In the second therapy, 4 samples were taken from 4 different sites-the normal skin, scars, the skin where artificial dermis and scalp skin grafting were performed, and the skin where only scalp skin grafting was performed. H-E staining, Masson staining, Aldehyde fuchsin staining, and scanning electron microscopy were used for histological observation. RESULTS: All skin grafts survived well. The Manchester Scar Scale score of the graft area was significantly reduced (P < 0.01) after the treatment. Histological examination showed obviously better dermis arrangement where artificial dermis and scalp grafting was performed. CONCLUSION: The therapy achieves better appearances and minimizes donor site morbidity. It is beneficial to physical and psychological development of children and provides an alternative to treat children with large scars.

Histopathology and Long-Term Outcome of Kidneys Transplanted From Donors With Severe Acute Kidney Injury.

BACKGROUND: Acute kidney injury is a treatable entity although difficult to recognize without diagnostic biopsy. We investigated the potential association between clinically defined deceased donors and acute kidney injury with preimplantation histological findings and recipient outcomes. METHODS: Kidney biopsies from donors were classified using the Acute Kidney Injury Network criteria and assessed for percentage glomerulosclerosis, tubular atrophy, interstitial fibrosis, and vascular narrowing with the Remuzzi score and for acute tubular necrosis. Differences in incidence rates of delayed graft function (DGF) and cumulative rejection episodes were compared between recipients transplanted with normal and 3 levels of acute kidney injury using the analysis of variance with Bonferroni correction ( P = .0012). RESULTS: Sixteen out of 335 donors showed a severe acute kidney injury level 3 with a median serum creatinine of 458 µmol/L. Fourteen (88%) had 0-3 Remuzzi score and were used for single kidney transplantation and 2 (12%) were used for dual kidney transplantation (score: 4-6). Recipients who received a kidney from a donor with level 3 acute kidney injury had a higher percentage of DGF (47%) without statistical significance ( P = .008). The rate of cumulative rejection (45%) at 2 years was not significantly increased ( P = .09). CONCLUSIONS: Recipients receiving level 3 acute kidney injury kidneys, selected with Remuzzi histopathological score and acute tubular necrosis assessment, had a greater incidence of DGF but a similar long-term cumulative rejection compared to no injury and level 1 and level 2 acute kidney injury donors. The application of the histopathological examination allowed expansion of the kidney donor pool.

The protective role of Toll-like receptor 3 and type-I interferons in the pathophysiology of vein graft disease.

BACKGROUND: Venous grafts are commonly used as conduits to bypass occluded arteries. Unfortunately, patency rates are limited by vein graft disease (VGD). Toll like receptors (TLRs) can be activated in vein grafts by endogenous ligands. This study aims to investigate the role of TLR3 in VGD. METHODS: Vein graft surgery was performed by donor caval vein interpositioning in the carotid artery of recipient Tlr2-/-, Tlr3-/-, Tlr4-/- and control mice. Vein grafts were harvested 7, 14 and 28d after surgery to perform immunohistochemical analysis. Expression of TLR-responsive genes in vein grafts was analysed using a RT2-profiler PCR Array. mRNA expression of type-I IFN inducible genes was measured with qPCR in bone marrow-derived macrophages (BMM). RESULTS: TLR2, TLR3 and TLR4 were observed on vein graft endothelial cells, smooth muscle cells and macrophages. Tlr3-/- vein grafts demonstrated no differences in vessel wall thickening after 7d, but after 14d a 2.0-fold increase (p = 0.02) and 28d a 1.8-fold increase (p = 0.009) compared to control vein grafts was observed, with an increased number of macrophages (p = 0.002) in the vein graft. Vessel wall thickening in Tlr4-/- decreased 0.6-fold (p = 0.04) and showed no differences in Tlr2-/- compared to control vein grafts. RT2-profiler array revealed a down-regulation of type-I IFN inducible genes in Tlr3-/- vein grafts. PolyI:C stimulated BMM of Tlr3-/- mice showed a reduction of Ifit1 (p = 0.003) and Mx1 (p < 0.0001) mRNA compared to control. CONCLUSIONS: We here demonstrate that TLR3 can play a protective role in VGD development, possibly regulated via type-I IFNs and a reduced inflammatory response.

Post-transplant cholangiopathy: Classification, pathogenesis, and preventive strategies.

Biliary complications are the most frequent cause of morbidity, re-transplantation, and even mortality after liver transplantation. In general, biliary leakage and anastomotic and non-anastomotic biliary strictures (NAS) can be recognized. There is no consensus on the exact definition of NAS and different names and criteria have been used in literature. We propose to use the term post-transplant cholangiopathy for the spectrum of abnormalities of large donor bile ducts, that includes NAS, but also intraductal casts and intrahepatic biloma formation, in the presence of a patent hepatic artery. Combinations of these manifestations of cholangiopathy are not infrequently found in the same liver and ischemia-reperfusion injury is generally considered the common underlying mechanism. Other factors that contribute to post-transplant cholangiopathy are biliary injury due to bile salt toxicity and immune-mediated injury. This review provides an overview of the various types of post-transplant cholangiopathy, the presumed pathogenesis, clinical implications, and preventive strategies.

Combined liver-kidney perfusion enhances protective effects of normothermic perfusion on liver grafts from donation after cardiac death.

It has been shown that combined liver-kidney normothermic machine perfusion (NMP) is able to better maintain the circuit's biochemical milieu. Nevertheless, whether the combined perfusion is superior to liver perfusion alone in protecting livers from donation after circulatory death (DCD) is unclear. We aimed to test the hypothesis and explored the mechanisms. Livers from 15 DCD pig donors were subjected to either static cold storage (group A), liver-alone NMP (group B), or combined liver-kidney NMP (group C). Livers were preserved for 6 hours and reperfused ex vivo for 2 hours to simulate transplantation or were transplanted in situ. During perfusion, group C showed an improved acid-base and biochemical environment in the circuit over group B. After reperfusion, the architecture of the liver grafts was best preserved in group C, followed by group B, then group A, as shown by the histology and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining of both hepatocytes and biliary epithelium. Ki-67 staining showed substantial hepatocyte proliferation and biliary epithelial regeneration after perfusion in group B and group C. Group C produced more bile in the reperfusion phase than those in group A and group B, with more physiological bile composition and less severe biliary epithelium injury. Von Willebrand factor-positive endothelial cells and E-selectin expression decreased in both group B and group C. Combined liver-kidney NMP not only produced more adenosine triphosphate, protected the nitric oxide signaling pathway, but also diminished oxidative stress (high mobility group box-1 protein and 8-hydroxy-2-deoxy guanosine levels) and inflammatory cytokine (IL6 and IL8) release when compared with liver-alone NMP and CS. In addition, the 7-day survival rate of liver transplant recipients was higher in group C than that in groups A and B. In conclusion, combined liver-kidney NMP can better protect DCD livers from warm ischemia and reperfusion injury probably by maintaining the stability of the internal environment and by abolishing oxidative stress injury. Liver Transplantation 24 67-79 2018 AASLD.

Management of portal hypertension before and after liver transplantation.

Orthotopic liver transplantation (OLT) represents a curative treatment option for end-stage liver disease (ESLD). Although epidemiology of ESLD has recently changed due to the rising prevalence of nonalcoholic fatty liver disease and the decreased burden of hepatitis C virus infections due to highly effective antiviral regimens, the management of portal hypertension (PHT) remains a clinical challenge in the pre- and post-OLT setting. The measurement of the hepatic venous pressure gradient represents the most reliable but invasive tool for assessment of the severity of PHT. Although novel liver ultrasound and magnetic resonance-based elastography methods have been developed, their value to screen for liver fibrosis and PHT in transplanted patients remains to be established. Nonselective beta-blockers represent the cornerstone of medical treatment of PHT, but more studies on their effects on clinical endpoints after OLT are needed. Statins are widely used to treat hyperlipidemia, which is a common condition after OLT. Although a growing body of evidence suggests that statins decrease portal pressure and PHT-related complications in ESLD, studies on potential benefits of statins after OLT are lacking. Finally, transjugular intrahepatic portosystemic shunts (TIPS) are effective in decreasing PHT and seem to decrease mortality on the OLT waiting list. Moreover, TIPS does not have an impact on liver function nor complicate the transplant surgical procedures. TIPS may also be used after OLT, but the evidence is limited. In conclusion, whereas the management of PHT in patients with ESLD is based on strong evidence, further data on the value of noninvasive monitoring tools as well as on medical and invasive treatment options in the post-OLT setting are needed to improve management strategies in patients with recurrent PHT after liver transplantation. Liver Transplantation 24 112-121 2018 AASLD.