Validating human and mouse tissues commonly used in atherosclerosis research with coronary and aortic reference tissue: similarities but profound differences in disease initiation and plaque stability.

Objective: Characterization of the atherosclerotic process fully relies on histological evaluation and staging through a consensus grading system. So far, a head-to-head comparison of atherosclerotic process in experimental models and tissue resources commonly applied in atherosclerosis research with the actual human atherosclerotic process is missing. Material and Methods: Aspects of the atherosclerotic process present in established murine atherosclerosis models and human carotid endarterectomy specimen were systematically graded using the modified American Heart Association histological classification (Virmani classification). Aspects were aligned with the atherosclerotic process observed in human coronary artery and aortic atherosclerosis reference tissues that were available through biobanks based on human tissue/organ donor material. Results: Apart from absent intraplaque hemorrhages in aortic lesions, the histological characteristics of the different stages of human coronary and aortic atherosclerosis are similar. Carotid endarterectomy samples all represent end-stage "fibrous calcified plaque" lesions, although secondary, progressive, and vulnerable lesions with gross morphologies similar to coronary/aortic lesions occasionally present along the primary lesions. For the murine lesions, clear histological parallels were observed for the intermediate lesion types ("pathological intimal thickening," and "early fibroatheroma"). However, none of the murine lesions studied progressed to an equivalent of late fibroatheroma or beyond. Notable contrasts were observed for disease initiation: whereas disease initiation in humans is characterized by a mesenchymal cell influx in the intima, the earliest murine lesions are exclusively intimal, with subendothelial accumulation foam cells. A mesenchymal (and medial) response are absent. In fact, it is concluded that the stage of "adaptive intimal thickening" is absent in all mouse models included in this study. Conclusions: The Virmani classification for coronary atherosclerosis can be applied for systematically grading experimental and clinical atherosclerosis. Application of this histological grading tool shows clear parallels for intermediate human and murine atherosclerotic lesions. However, clear contrasts are observed for disease initiation, and late stage atherosclerotic lesions. Carotid endarterectomy all represent end-stage fibrous calcified plaque lesions, although secondary earlier lesions may present in a subset of samples.

Quality assessment of donor liver procurement surgery using an unadjusted CUSUM prediction model. A practical nationwide evaluation.

BACKGROUND: The aim of this study was to analyze the value of the unadjusted CUSUM graph of liver surgical injury and discard rates in organ procurement in the Netherlands. METHODS: Unadjusted CUSUM graphs were plotted for surgical injury (C event) and discard rate (C2 event) from procured livers accepted for transplantation for each local procurement team compared with the total national cohort. The average incidence for each outcome was used as benchmark based on procurement quality forms (Sep 2010-Oct 2018). The data from the five Dutch procuring teams were blind-coded. RESULTS: The C and C2 event rate were 17% and 1.9%, respectively (n = 1265). A total of 12 CUSUM charts were plotted for the national cohort and the five local teams. National CUSUM charts showed an overlapping "alarm signal." This overlapping signal for both C and C2, albeit a different time period, was only found in one local team. The other CUSUM alarm signal went off for two separate local teams, but only for C events or C2 events respectively, and at different points in time. The other remaining CUSUM charts showed no alarm signaling. CONCLUSION: The unadjusted CUSUM chart is a simple and effective monitoring tool in following performance quality of organ procurement for liver transplantation. Both national and local recorded CUSUMs are useful to see the implication of national and local effects on organ procurement injury. Both procurement injury and organ discard are equally important in this analysis and need to be separately CUSUM charted.

A nationwide assessment of hepatocellular adenoma resection: Indications and pathological discordance.

Hepatocellular adenomas (HCAs) are benign liver tumors associated with bleeding or malignant transformation. Data on the indication for surgery are scarce. We analyzed indications and outcome of patients operated for HCAs < 50 mm compared to HCAs ≥ 50 mm. Changes in final postoperative diagnosis were assessed. We performed a retrospective study that included patients who underwent resection for (suspected) HCAs in the Netherlands from 2014 to 2019. Indication for resection was analyzed and stratified for small (<50 mm) and large (≥50 mm) tumors. Logistic regression analysis was performed on factors influencing change in tumor diagnosis. Out of 222 patients who underwent surgery, 44 (20%) patients had a tumor <50 mm. Median age was 46 (interquartile range [IQR], 33-56) years in patients with small tumors and 37 (IQR, 31-46) years in patients with large tumors ( p  = 0.016). Patients with small tumors were more frequently men (21% vs. 5%, p  = 0.002). Main indications for resection in patients with small tumors were suspicion of (pre)malignancy (55%), (previous) bleeding (14%), and male sex (11%). Patients with large tumors received operations because of tumor size >50 mm (52%), suspicion of (pre)malignancy (28%), and (previous) bleeding (5.1%). No difference was observed in HCA-subtype distribution between small and large tumors. Ninety-six (43%) patients had a postoperative change in diagnosis. Independent risk factors for change in diagnosis were tumor size <50 mm (adjusted odds ratio [aOR], 3.4; p  < 0.01), male sex (aOR, 3.7; p  = 0.03), and lack of hepatobiliary contrast-enhanced magnetic resonance imaging (CE-MRI) (aOR, 1.8; p  = 0.04). Resection for small (suspected) HCAs was mainly indicated by suspicion of (pre)malignancy, whereas for large (suspected) HCAs, tumor size was the most prevalent indication. Male sex, tumor size <50 mm, and lack of hepatobiliary CE-MRI were independent risk factors for postoperative change in tumor diagnosis.

Donor characteristics and their impact on kidney transplantation outcomes: Results from two nationwide instrumental variable analyses based on outcomes of donor kidney pairs accepted for transplantation.

Background: Donor-characteristics and donor characteristics-based decision algorithms are being progressively used in the decision process whether or not to accept an available donor kidney graft for transplantation. While this may improve outcomes, the performance characteristics of the algorithms remains moderate. To estimate the impact of donor factors of grafts accepted for transplantation on transplant outcomes, and to test whether implementation of donor-characteristics-based algorithms in clinical decision-making is justified, we applied an instrumental variable analysis to outcomes for kidney donor pairs transplanted in different individuals. Methods: This analysis used (dis)congruent outcomes of kidney donor pairs as an instrument and was based on national transplantation registry data for all donor kidney pairs transplanted in separate individuals in the Netherlands (1990-2018, 2,845 donor pairs), and the United Kingdom (UK, 2000-2018, 11,450 pairs). Incident early graft loss (EGL) was used as the primary discriminatory factor. It was reasoned that a scenario with a dominant impact of donor variables on transplantation outcomes would result in high concordance of EGL in both recipients, whilst dominance of asymmetrical outcomes could indicate a more complex scenario, involving an interaction of donor, procedural and recipient factors. Findings: Incidences of congruent EGL (Netherlands: 1·2%, UK: 0·7%) were slightly lower than the arithmetical (stochastic) incidences, suggesting that once a graft has been accepted for transplantation, donor factors minimally contribute to incident EGL. A long-term impact of donor factors was explored by comparing outcomes for functional grafts from donor pairs with asymmetrical vs. symmetrical outcomes. Recipient survival was similar for both groups, but a slightly compromised graft survival was observed for grafts with asymmetrical outcomes in the UK cohort: (10-years Hazard Ratio for graft loss: 1·18 [1·03-1·35] p<0·018); and 5 years eGFR (48·6 [48·3-49·0] vs. 46·0 [44·5-47·6] ml/min in the symmetrical outcome group, p<0·001). Interpretation: Our results suggest that donor factors for kidney grafts deemed acceptable for transplantation impact minimally on transplantation outcomes. A strong reliance on donor factors and/or donor-characteristics-based decision algorithms could result in unjustified rejection of grafts. Future efforts to optimize transplant outcomes should focus on a better understanding of the recipient factors underlying transplant outcomes. Funding: None.

Preclinical models versus clinical renal ischemia reperfusion injury: A systematic review based on metabolic signatures.

Despite decennia of research and numerous successful interventions in the preclinical setting, renal ischemia reperfusion (IR) injury remains a major problem in clinical practice, pointing toward a translational gap. Recently, two clinical studies on renal IR injury (manifested either as acute kidney injury or as delayed graft function) identified metabolic derailment as a key driver of renal IR injury. It was reasoned that these unambiguous metabolic findings enable direct alignment of clinical with preclinical data, thereby providing the opportunity to elaborate potential translational hurdles between preclinical research and the clinical context. A systematic review of studies that reported metabolic data in the context of renal IR was performed according to the PRISMA guidelines. The search (December 2020) identified 35 heterogeneous preclinical studies. The applied methodologies were compared, and metabolic outcomes were semi-quantified and aligned with the clinical data. This review identifies profound methodological challenges, such as the definition of IR injury, the follow-up time, and sampling techniques, as well as shortcomings in the reported metabolic information. In light of these findings, recommendations are provided in order to improve the translatability of preclinical models of renal IR injury.

Study protocol for a multicentre nationwide prospective cohort study to investigate the natural course and clinical outcome in benign liver tumours and cysts in the Netherlands: the BELIVER study.

INTRODUCTION: Benign liver tumours and cysts (BLTCs) comprise a heterogeneous group of cystic and solid lesions, including hepatic haemangioma, focal nodular hyperplasia and hepatocellular adenoma. Some BLTCs, for example, (large) hepatocellular adenoma, are at risk of complications. Incidence of malignant degeneration or haemorrhage is low in most other BLTCs. Nevertheless, the diagnosis BLTC may carry a substantial burden and patients may be symptomatic, necessitating treatment. The indications for interventions remain matter of debate. The primary study aim is to investigate patient-reported outcomes (PROs) of patients with BLTCs, with special regards to the influence of invasive treatment as compared with the natural course of the disease. METHODS AND ANALYSIS: A nationwide observational cohort study of patients with BLTC will be performed between October 2021 and October 2026, the minimal follow-up will be 2 years. During surveillance, a questionnaire regarding symptoms and their impact will be sent to participants on a biannual basis and more often in case of invasive intervention. The questionnaire was previously developed based on PROs considered relevant to patients with BLTCs and their caregivers. Most questionnaires will be administered by computerised adaptive testing through the Patient-Reported Outcomes Measurement Information System. Data, such as treatment outcomes, will be extracted from electronic patient files. Multivariable analysis will be performed to identify patient and tumour characteristics associated with significant improvement in PROs or a complicated postoperative course. ETHICS AND DISSEMINATION: The study was assessed by the Medical Ethics Committee of the University Medical Center Groningen and the Amsterdam UMC. Local consultants will provide information and informed consent will be asked of all patients. Results will be published in a peer-reviewed journal. STUDY REGISTRATION: NL8231-10 December 2019; Netherlands Trial Register.

Metabolic needs of the kidney graft undergoing normothermic machine perfusion.

Normothermic machine perfusion (NMP) is emerging as a novel preservation strategy. During NMP, the organ is maintained in a metabolically active state that may not only provide superior organ preservation, but that also facilitates viability testing before transplantation, and ex situ resuscitation of marginal kidney grafts. Although the prevailing perfusion protocols for renal NMP are refined from initial pioneering studies concerning short periods of NMP, it could be argued that these protocols are not optimally tailored to address the putatively compromised metabolic plasticity of marginal donor grafts (i.e., in the context of viability testing and/or preservation), or to meet the metabolic prerequisites associated with prolonged perfusions and the required anabolic state in the context of organ regeneration. Herein, we provide a theoretical framework for the metabolic requirements for renal NMP. Aspects are discussed along the lines of carbohydrates, fatty acids, amino acids, and micronutrients required for optimal NMP of an isolated kidney. In addition, considerations for monitoring aspects of metabolic status during NMP are discussed.

Circumventing the Crabtree effect in cell culture: A systematic review.

Metabolic reprogramming and mitochondrial dysfunction are central elements in a broad variety of physiological and pathological processes. While cell culture established itself as a versatile technique for the elaboration of physiology and disease, studying metabolism using standard cell culture protocols is profoundly interfered by the Crabtree effect. This phenomenon refers to the adaptation of cultured cells to a glycolytic phenotype, away from oxidative phosphorylation in glucose-containing medium, and questions the applicability of cell culture in certain fields of research. In this systematic review we aim to provide a comprehensive overview and critical appraisal of strategies reported to circumvent the Crabtree effect.

Donor diabetes mellitus is a risk factor for diminished outcome after liver transplantation: a nationwide retrospective cohort study.

With the growing incidence of diabetes mellitus (DM), an increasing number of organ donors with DM can be expected. We sought to investigate the association between donor DM with early post-transplant outcomes. From a national cohort of adult liver transplant recipients (1996-2016), all recipients transplanted with a liver from a DM donor (n = 69) were matched 1:2 with recipients of livers from non-DM donors (n = 138). The primary end-point included early post-transplant outcome, such as the incidence of primary nonfunction (PNF), hepatic artery thrombosis (HAT), and 90-day graft survival. Cox regression analysis was used to analyze the impact of donor DM on graft failure. PNF was observed in 5.8% of grafts from DM donors versus 2.9% of non-DM donor grafts (P = 0.31). Recipients of grafts derived from DM donors had a higher incidence of HAT (8.7% vs. 2.2%, P = 0.03) and decreased 90-day graft survival (88.4% [70.9-91.1] vs. 96.4% [89.6-97.8], P = 0.03) compared to recipients of grafts from non-DM donors. The adjusted hazard ratio for donor DM on graft survival was 2.21 (1.08-4.53, P = 0.03). In conclusion, donor DM is associated with diminished outcome early after liver transplantation. The increased incidence of HAT after transplantation of livers from DM donors requires further research.

Results of an explorative clinical evaluation suggest immediate and persistent post-reperfusion metabolic paralysis drives kidney ischemia reperfusion injury.

Delayed graft function is the manifestation of ischemia reperfusion injury in the context of kidney transplantation. While hundreds of interventions successfully reduce ischemia reperfusion injury in experimental models, all clinical interventions have failed. This explorative clinical evaluation examined possible metabolic origins of clinical ischemia reperfusion injury combining data from 18 pre- and post-reperfusion tissue biopsies with 36 sequential arteriovenous blood samplings over the graft in three study groups. These groups included living and deceased donor grafts with and without delayed graft function. Group allocation was based on clinical outcome. Magic angle NMR was used for tissue analysis and mass spectrometry-based platforms were used for plasma analysis. All kidneys were functional at one-year. Integration of metabolomic data identified a discriminatory profile to recognize future delayed graft function. This profile was characterized by post-reperfusion ATP/GTP catabolism (significantly impaired phosphocreatine recovery and significant persistent (hypo)xanthine production) and significant ongoing tissue damage. Failing high-energy phosphate recovery occurred despite activated glycolysis, fatty-acid oxidation, glutaminolysis and autophagia, and related to a defect at the level of the oxoglutarate dehydrogenase complex in the Krebs cycle. Clinical delayed graft function due to ischemia reperfusion injury associated with a post-reperfusion metabolic collapse. Thus, efforts to quench delayed graft function due to ischemia reperfusion injury should focus on conserving metabolic competence, either by preserving the integrity of the Krebs cycle and/or by recruiting metabolic salvage pathways.

Improving outcomes for donation after circulatory death kidney transplantation: Science of the times.

The use of kidneys donated after circulatory death (DCD) remains controversial due to concerns with regard to high incidences of early graft loss, delayed graft function (DGF), and impaired graft survival. As these concerns are mainly based on data from historical cohorts, they are prone to time-related effects and may therefore not apply to the current timeframe. To assess the impact of time on outcomes, we performed a time-dependent comparative analysis of outcomes of DCD and donation after brain death (DBD) kidney transplantations. Data of all 11,415 deceased-donor kidney transplantations performed in The Netherlands between 1990-2018 were collected. Based on the incidences of early graft loss, two eras were defined (1998-2008 [n = 3,499] and 2008-2018 [n = 3,781]), and potential time-related effects on outcomes evaluated. Multivariate analyses were applied to examine associations between donor type and outcomes. Interaction tests were used to explore presence of effect modification. Results show clear time-related effects on posttransplant outcomes. The 1998-2008 interval showed compromised outcomes for DCD procedures (higher incidences of DGF and early graft loss, impaired 1-year renal function, and inferior graft survival), whereas DBD and DCD outcome equivalence was observed for the 2008-2018 interval. This occurred despite persistently high incidences of DGF in DCD grafts, and more adverse recipient and donor risk profiles (recipients were 6 years older and the KDRI increased from 1.23 to 1.39 and from 1.35 to 1.49 for DBD and DCD donors). In contrast, the median cold ischaemic period decreased from 20 to 15 hours. This national study shows major improvements in outcomes of transplanted DCD kidneys over time. The time-dependent shift underpins that kidney transplantation has come of age and DCD results are nowadays comparable to DBD transplants. It also calls for careful interpretation of conclusions based on historical cohorts, and emphasises that retrospective studies should correct for time-related effects.

A nationwide evaluation of deceased donor kidney transplantation indicates detrimental consequences of early graft loss.

Early graft loss (EGL) is a feared outcome of kidney transplantation. Consequently, kidneys with an anticipated risk of EGL are declined for transplantation. In the most favorable scenario, with optimal use of available donor kidneys, the donor pool size is balanced by the risk of EGL, with a tradeoff dictated by the consequences of EGL. To gauge the consequence of EGL we systematically evaluated its impact in an observational study that included all 10,307 deceased-donor kidney transplantations performed in The Netherlands between 1990 and 2018. Incidence of EGL, defined as graft loss within 90 days, in primary transplantation was 8.2% (699/8,511). The main causes were graft rejection (30%), primary nonfunction (25%), and thrombosis or infarction (20%). EGL profoundly impacted short- and long-term patient survival (adjusted hazard ratio; 95% confidence interval: 8.2; 5.1-13.2 and 1.7; 1.3-2.1, respectively). Of the EGL recipients who survived 90 days after transplantation (617/699) only 440 of the 617 were relisted for re-transplantation. Of those relisted, only 298 were ultimately re-transplanted leading to an actual re-transplantation rate of 43%. Noticeably, re-transplantation was associated with a doubled incidence of EGL, but similar long-term graft survival (adjusted hazard ratio 1.1; 0.6-1.8). Thus, EGL after kidney transplantation is a medical catastrophe with high mortality rates, low relisting rates, and increased risk of recurrent EGL following re-transplantation. This implies that detrimental outcomes also involve convergence of risk factors in recipients with EGL. The 8.2% incidence of EGL minimally impacted population mortality, indicating this incidence is acceptable.

The Neglectable Impact of Delayed Graft Function on Long-term Graft Survival in Kidneys Donated After Circulatory Death Associates With Superior Organ Resilience.

OBJECTIVE: To explore putative different impacts of delayed graft function (DGF) on long-term graft survival in kidneys donated after brain death (DBD) and circulatory death (DCD). BACKGROUND: Despite a 3-fold higher incidence of DGF in DCD grafts, large studies show equivalent long-term graft survival for DBD and DCD grafts. This observation implies a differential impact of DGF on DBD and DCD graft survival. The contrasting impact is remarkable and yet unexplained. METHODS: The impact of DGF on DBD and DCD graft survival was evaluated in 6635 kidney transplants performed in The Netherlands. DGF severity and functional recovery dynamics were assessed for 599 kidney transplants performed at the Leiden Transplant Center. Immunohistochemical staining, gene expression profiling, and Ingenuity Pathway Analysis were used to identify differentially activated pathways in DBD and DCD grafts. RESULTS: While DGF severely impacted 10-year graft survival in DBD grafts (HR 1.67; P < 0.001), DGF did not impact graft survival in DCD grafts (HR 1.08; P = 0.63). Shorter dialysis periods and superior posttransplant eGFRs in DBD grafts show that the differential impact was not caused by a more severe DGF phenotype in DBD grafts. Immunohistochemical evaluation indicates that pathways associated with tissue resilience are present in kidney grafts. Molecular evaluation showed selective activation of resilience-associated pathways in DCD grafts. CONCLUSIONS: This study shows an absent impact of DGF on long-term graft survival in DCD kidneys. Molecular evaluation suggests that the differential impact of DGF between DBD and DCD grafts relates to donor-type specific activation of resilience pathways in DCD grafts.

Postponed or immediate drainage of infected necrotizing pancreatitis (POINTER trial): study protocol for a randomized controlled trial.

BACKGROUND: Infected necrosis complicates 10% of all acute pancreatitis episodes and is associated with 15-20% mortality. The current standard treatment for infected necrotizing pancreatitis is the step-up approach (catheter drainage, followed, if necessary, by minimally invasive necrosectomy). Catheter drainage is preferably postponed until the stage of walled-off necrosis, which usually takes 4 weeks. This delay stems from the time when open necrosectomy was the standard. It is unclear whether such delay is needed for catheter drainage or whether earlier intervention could actually be beneficial in the current step-up approach. The POINTER trial investigates if immediate catheter drainage in patients with infected necrotizing pancreatitis is superior to the current practice of postponed intervention. METHODS: POINTER is a randomized controlled multicenter superiority trial. All patients with necrotizing pancreatitis are screened for eligibility. In total, 104 adult patients with (suspected) infected necrotizing pancreatitis will be randomized to immediate (within 24 h) catheter drainage or current standard care involving postponed catheter drainage. Necrosectomy, if necessary, is preferably postponed until the stage of walled-off necrosis, in both treatment arms. The primary outcome is the Comprehensive Complication Index (CCI), which covers all complications between randomization and 6-month follow up. Secondary outcomes include mortality, complications, number of (repeat) interventions, hospital and intensive care unit (ICU) lengths of stay, quality-adjusted life years (QALYs) and direct and indirect costs. Standard follow-up is at 3 and 6 months after randomization. DISCUSSION: The POINTER trial investigates if immediate catheter drainage in infected necrotizing pancreatitis reduces the composite endpoint of complications, as compared with the current standard treatment strategy involving delay of intervention until the stage of walled-off necrosis. TRIAL REGISTRATION: ISRCTN, 33682933 . Registered on 6 August 2015. Retrospectively registered.

Superiority of Step-up Approach vs Open Necrosectomy in Long-term Follow-up of Patients With Necrotizing Pancreatitis.

BACKGROUND & AIMS: In a 2010 randomized trial (the PANTER trial), a surgical step-up approach for infected necrotizing pancreatitis was found to reduce the composite endpoint of death or major complications compared with open necrosectomy; 35% of patients were successfully treated with simple catheter drainage only. There is concern, however, that minimally invasive treatment increases the need for reinterventions for residual peripancreatic necrotic collections and other complications during the long term. We therefore performed a long-term follow-up study. METHODS: We reevaluated all the 73 patients (of the 88 patients randomly assigned to groups) who were still alive after the index admission, at a mean 86 months (±11 months) of follow-up. We collected data on all clinical and health care resource utilization endpoints through this follow-up period. The primary endpoint was death or major complications (the same as for the PANTER trial). We also measured exocrine insufficiency, quality of life (using the Short Form-36 and EuroQol 5 dimensions forms), and Izbicki pain scores. RESULTS: From index admission to long-term follow-up, 19 patients (44%) died or had major complications in the step-up group compared with 33 patients (73%) in the open-necrosectomy group (P = .005). Significantly lower proportions of patients in the step-up group had incisional hernias (23% vs 53%; P = .004), pancreatic exocrine insufficiency (29% vs 56%; P = .03), or endocrine insufficiency (40% vs 64%; P = .05). There were no significant differences between groups in proportions of patients requiring additional drainage procedures (11% vs 13%; P = .99) or pancreatic surgery (11% vs 5%; P = .43), or in recurrent acute pancreatitis, chronic pancreatitis, Izbicki pain scores, or medical costs. Quality of life increased during follow-up without a significant difference between groups. CONCLUSIONS: In an analysis of long-term outcomes of trial participants, we found the step-up approach for necrotizing pancreatitis to be superior to open necrosectomy, without increased risk of reinterventions.

Retrospective study on detection, treatment, and clinical outcome of graft thrombosis following pancreas transplantation.

Complete graft thrombosis is the leading cause of early graft loss following pancreas transplantation. Partial thrombosis is usually subclinical and discovered on routine imaging. Treatment options may vary in such cases. We describe the incidence and relevance of partial graft thrombosis in a large transplant center. All consecutive pancreas transplantation at our center (2004-2015) were included in this study. Radiological follow-up, type and quantity of thrombosis prophylaxis, complications and, graft and patient survival were collected. Partial thrombosis and follow-up were also studied. All 230 pancreas transplantations were included in the analysis. Computed tomography was performed in most cases (89.1%). Early graft failure occurred in 23 patients (13/23 due to graft thrombosis, 3/23 bleeding, 1/23 anastomotic leakage, 6/23 secondary to antibody mediated rejection). There was evidence of partial thrombosis in 59 cases (26%), of which the majority was treated with heparin and a vitamin K antagonist with graft preservation in 57/59 patients (97%). Thrombosis is the leading cause of early graft loss following pancreas transplantation. Computed tomography allows for early detection of partial thrombosis, which is usually subclinical. Partial graft thrombosis occurs in about 25% of all cases. In this series, treatment with anticoagulant therapy (heparin and vitamin K antagonist) resulted in graft preservation in almost all cases.

Qualitative evaluation of coronary atherosclerosis in a large cohort of young and middle-aged Dutch tissue donors implies that coronary thrombo-embolic manifestations are stochastic.

BACKGROUND AND AIMS: With the intention to gain support for the hypothesis that incident ischemic complications of atherosclerotic disease involve a stochastic aspect, we performed a histological, qualitative evaluation of the epidemiology of coronary atherosclerotic disease in a cohort of aortic valve donors. PATIENTS AND METHODS: Donors (n = 695, median age 54, range 11-65 years) were dichotomized into a non-cardiovascular (non-CVD) and a cardiovascular disease death (CVD) group. Consecutive 5 mm proximal left coronary artery segments were Movat stained, and the atherosclerotic burden for each segment was graded (revised AHA-classification). RESULTS: Non-CVD and CVD groups showed steep increase of atherosclerosis severity beyond the age of 40, resulting in an endemic presence of advanced atherosclerosis in men over 40 and women over 50 years. In fact, only 19% of the non-CVD and 6% of the CVD donors over 40 years were classified with a normal LCA or a so called non-progressive lesion type. Fibrous calcified plaques (FCP), the consolidated remnants of earlier ruptured lesions, dominated in both non-CVD and CVD donors. Estimates of the atherosclerosis burden (i.e. average lesion grade, proportion of FCPs, and average number of FCPs per cross-section) were all higher in the CVD group (p<1.10-16, p<0.0001, and p<0.05, respectively). CONCLUSIONS: Dominance of consolidated FCP lesions in males over 40 and females over 50 years, show that plaque ruptures in the left coronary artery are common. However, the majority of these ruptures remain asymptomatic. This implies that the atherosclerotic process is repetitive. A relative difference in disease burden between CVD and non-CVD donors supports the concept that complications of atherosclerotic disease involve a stochastic element.

No indications for platelet activation in acute clinical myocardial or renal ischemia/reperfusion injury.

The pathophysiology of ischemia/reperfusion (I/R) injury is complex and poorly understood. Animal studies imply platelet activation as an initiator of the inflammatory response upon reperfusion. However, it remains unclear whether and how these results translate to clinical I/R. This study evaluates putative platelet activation in the context of two forms of clinical I/R (heart valve surgery with aortic-cross clamping, n = 39 and kidney transplantation, n = 34). The technique of sequential selective arteriovenous (AV) measurements over the reperfused organs was applied to exclude the influence of systemic changes occurring during surgery while simultaneously maximizing sensitivity. Platelet activation and degranulation was evaluated by assessing the expression levels of established markers, i.e. RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted), ß-thromboglobulin (ß-TG), platelet-derived growth factor (PDGF)-BB and CXCL8 (known as interleukin-8), and by employing an in-vitro assay that specifically tests for platelet excitability. Moreover, a histological analysis was performed by means of CD41 staining. Results show stable RANTES, ß-TG, PDGF-BB and CXCL8 AV-concentrations within the first half hour over the reperfused organs, suggesting that myocardial and renal I/R are not associated with platelet activation. Results from the platelet excitability assay were in line with these findings and indicated reduced and stable platelet excitability following renal and myocardial reperfusion, respectively. Histological analysis yield evidence of platelet marginalization in the reperfused organs. In conclusion, results from this study do not support a role for platelet activation in early phases of clinical I/R injury.

CRIPTO promotes an aggressive tumour phenotype and resistance to treatment in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Despite increasing treatment options for this disease, prognosis remains poor. CRIPTO (TDGF1) protein is expressed at high levels in several human tumours and promotes oncogenic phenotype. Its expression has been correlated to poor prognosis in HCC. In this study, we aimed to elucidate the basis for the effects of CRIPTO in HCC. We investigated CRIPTO expression levels in three cohorts of clinical cirrhotic and HCC specimens. We addressed the role of CRIPTO in hepatic tumourigenesis using Cre-loxP-controlled lentiviral vectors expressing CRIPTO in cell line-derived xenografts. Responses to standard treatments (sorafenib, doxorubicin) were assessed directly on xenograft-derived ex vivo tumour slices. CRIPTO-overexpressing patient-derived xenografts were established and used for ex vivo drug response assays. The effects of sorafenib and doxorubicin treatment in combination with a CRIPTO pathway inhibitor were tested in ex vivo cultures of xenograft models and 3D cultures. CRIPTO protein was found highly expressed in human cirrhosis and hepatocellular carcinoma specimens but not in those of healthy participants. Stable overexpression of CRIPTO in human HepG2 cells caused epithelial-to-mesenchymal transition, increased expression of cancer stem cell markers, and enhanced cell proliferation and migration. HepG2-CRIPTO cells formed tumours when injected into immune-compromised mice, whereas HepG2 cells lacking stable CRIPTO overexpression did not. High-level CRIPTO expression in xenograft models was associated with resistance to sorafenib, which could be modulated using a CRIPTO pathway inhibitor in ex vivo tumour slices. Our data suggest that a subgroup of CRIPTO-expressing HCC patients may benefit from a combinatorial treatment scheme and that sorafenib resistance may be circumvented by inhibition of the CRIPTO pathway. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.