Fluorescence-guided surgery using cetuximab-800CW in patients with penile carcinoma.

OBJECTIVE: To investigate the feasibility of fluorescence molecular imaging (FMI), using cetuximab-800CW, as an intraoperative tool to determine surgical margins in penile squamous cell carcinoma (PSCC). PATIENTS AND METHODS: A total of 11 patients with PSCC received 75 mg cetuximab followed by 15 mg cetuximab-800CW 2 days before surgery. FMI of the whole excision specimen and tissue slices was performed. Fluorescence visualisation was correlated to histopathology. Based on tumour and healthy tissue regions of interest, mean fluorescence intensity was calculated for each individual patient. RESULTS: Significant differences between tumour and healthy mean fluorescence intensity were found with tumour-to-background ratios of a median (IQR) of 1.51 (0.99) and a mean (SD) of 1.51 (0.32) in the excision specimen and tissue slices, respectively. One patient showed a high relative fluorescence intensity with a signal-to-background ratio of 1.79, corresponding to a tumour-positive margin on fresh frozen sectioning. CONCLUSION: In this Phase I study we showed that cetuximab-800CW seems suitable to discriminate PSCC from background tissue. The tracer was well tolerated, and no false positive spots were seen.

Metabolic Dysfunction-Associated Steatotic Liver Disease in a Dish: Human Precision-Cut Liver Slices as a Platform for Drug Screening and Interventions.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a growing healthcare problem with limited therapeutic options. Progress in this field depends on the availability of reliable preclinical models. Human precision-cut liver slices (PCLSs) have been employed to replicate the initiation of MASLD, but a comprehensive investigation into MASLD progression is still missing. This study aimed to extend the current incubation time of human PCLSs to examine different stages in MASLD. Healthy human PCLSs were cultured for up to 96 h in a medium enriched with high sugar, high insulin, and high fatty acids to induce MASLD. PCLSs displayed hepatic steatosis, characterized by accumulated intracellular fat. The development of hepatic steatosis appeared to involve a time-dependent impact on lipid metabolism, with an initial increase in fatty acid uptake and storage, and a subsequent down-regulation of lipid oxidation and secretion. PCLSs also demonstrated liver inflammation, including increased pro-inflammatory gene expression and cytokine production. Additionally, liver fibrosis was also observed through the elevated production of pro-collagen 1a1 and tissue inhibitor of metalloproteinase-1 (TIMP1). RNA sequencing showed that the tumor necrosis factor alpha (TNFα) signaling pathway and transforming growth factor beta (TGFß) signaling pathway were consistently activated, potentially contributing to the development of inflammation and fibrosis. In conclusion, the prolonged incubation of human PCLSs can establish a robust ex vivo model for MASLD, facilitating the identification and evaluation of potential therapeutic interventions.

Intraductal papillary neoplasms of the bile ducts: a comparative study of a rare disease in Europe and Nagoya, Japan.

BACKGROUND: Intraductal papillary neoplasm of the bile ducts (IPNB) is a rare disease in Western countries. The aim of this study was to compare tumor characteristics, management strategies, and outcomes between Western and Eastern patients who underwent surgical resection for IPNB. METHODS: A multi-institutional retrospective series of patients with IPNB undergoing surgery between January 2010 and December 2020 was gathered under the auspices of the European-African Hepato-Pancreato-Biliary Association (E-AHPBA), and at Nagoya University Hospital, Japan. RESULTS: A total of 85 patients (51% male; median age 66 years) from 28 E-AHPBA centers were compared to 91 patients (64% male; median age 71 years) from Nagoya. Patients in Europe had more multiple lesions (23% vs 2%, P < .001), less invasive carcinoma (42% vs 85%, P < .001), and more intrahepatic tumors (52% vs 24%, P < .001) than in Nagoya. Patients in Europe experienced less 90-day grade >3 Clavien-Dindo complications (33% vs 68%, P < .001), but higher 90-day mortality rate (7.0% vs 0%, P = .03). R0 resections (81% vs 82%) were similar. Overall survival, excluding 90-day postoperative deaths, was similar in both regions. DISCUSSION: Despite performing more extensive resections, the low perioperative mortality rate observed in Nagoya was probably influenced by a combination of patient-, tumor-, and surgery-related factors.

Human precision-cut cystic duct and gallbladder slices: a novel method for studying cholangiopathies.

Background and aims: Precision-cut tissue slices (PCTS) are widely used as an ex vivo culture tissue culture technique to study pathogeneses of diseases and drug activities in organs in vitro. A novel application of the PCTS model may be in the field of translational research into cholangiopathies such as biliary atresia. Therefore, the aim of this study was to apply the precision-cut slice technique to human bile duct and gallbladder tissue. Methods: Cystic duct and gallbladder tissue derived from patients undergoing a cholecystectomy were collected, preserved and used for preparation of precision-cut cystic duct slices (PCCDS) and precision-cut gallbladder slices (PCGS). The PCCDS and PCGS were prepared using a mechanical tissue slicer and subsequently incubated for 24 and 48 h respectively in William's Medium E (WME) culture medium. Viability was assessed based on ATP/protein content and tissue morphology [hematoxylin and eosin (H&E) staining]. Results: It was shown that viability, assessed by the ATP/protein content and morphology, of the PCCDS (n = 8) and PCGS (n = 8) could be maintained over the 24 and 48 h incubation period respectively. ATP/protein content of the PCCDS increased significantly from 0.58 ± 0.13 pmol/µg at 0 h to 2.4 ± 0.29 pmol/µg after 24 h incubation (P = .0003). A similar significant increase from 0.94 ± 0.22 pmol/µg at 0 h to 3.7 ± 0.41 pmol/µg after 24 h (P = .0005) and 4.2 ± 0.47 pmol/µg after 48 h (P = .0002) was observed in the PCGS. Morphological assessment of the PCCDS and PCGS showed viable tissue at 0 h and after 24 and 48 h incubation respectively. Conclusion: This study is the first to report on the use of the PCTS model for human gallbladder and cystic duct tissue. PCCDS and PCGS remain viable for an incubation period of at least 24 h, which makes them suitable for research purposes in the field of cholangiopathies, including biliary atresia.

Loss of Endothelial Glycocalyx During Normothermic Machine Perfusion of Porcine Kidneys Irrespective of Pressure and Hematocrit.

Normothermic machine perfusion (NMP) is a promising modality for marginal donor kidneys. However, little is known about the effects of NMP on causing endothelial glycocalyx (eGC) injury. This study aims to evaluate the effects of NMP on eGC injury in marginal donor kidneys and whether this is affected by perfusion pressures and hematocrits. Methods: Porcine slaughterhouse kidneys (n = 6/group) underwent 35 min of warm ischemia. Thereafter, the kidneys were preserved with oxygenated hypothermic machine perfusion for 3 h. Subsequently, 4 h of NMP was applied using pressure-controlled perfusion with an autologous blood-based solution containing either 12%, 24%, or 36% hematocrit. Pressures of 55, 75, and 95 mm Hg were applied in the 24% group. Perfusate, urine, and biopsy samples were collected to determine both injury and functional parameters. Results: During NMP, hyaluronan levels in the perfusate increased significantly (P < 0.0001). In addition, the positivity of glyco-stained glycocalyx decreased significantly over time, both in the glomeruli (P = 0.024) and peritubular capillaries (P = 0.003). The number of endothelial cells did not change during NMP (P = 0.157), whereas glomerular endothelial expression of vascular endothelial growth factor receptor-2 decreased significantly (P < 0.001). Microthrombi formation was significantly increased after NMP. The use of different pressures and hematocrits did not affect functional parameters during perfusion. Conclusions: NMP is accompanied with eGC and vascular endothelial growth factor receptor-2 loss, without significant loss of endothelial cells. eGC loss was not affected by the different pressures and hematocrits used. It remains unclear whether endothelial injury during NMP has harmful consequences for the transplanted kidney.

The association of urinary epidermal growth factors with ADPKD disease severity and progression.

BACKGROUND: The epidermal growth factor receptor (EGFR) pathway is involved in kidney tissue repair and growth. Preclinical interventional data and scarce human data have suggested a role for this pathway in the pathophysiology of autosomal dominant polycystic kidney disease (ADPKD), while other data have suggested that its activation is causally linked to repair of damaged kidney tissue. We hypothesize that urinary EGFR ligands, as a reflection of EGFR activity, are associated with kidney function decline in ADPKD in the context of tissue repair following injury, and as the disease progresses as a sign of insufficient repair. METHODS: In the present study, we measured the EGFR ligands, EGF and heparin binding-EGF (HB-EGF), in 24-h urine samples of 301 ADPKD patients and 72 age- and sex-matched living kidney donors to dissect the role of the EGFR pathway in ADPKD. During a median follow-up of 2.5 years, the association of urinary EGFR ligand excretion with annual change in estimated glomerular filtration rate (eGFR) and height-adjusted total kidney volume in ADPKD patients was analyzed using mixed-models methods, and the expression of three closely related EGFR family receptors in ADPKD kidney tissue was investigated by immunohistochemistry. Additionally, the effect of reducing renal mass (after kidney donation), was assessed to investigate whether urinary EGF matches this reduction and thus reflects the amount of remaining healthy kidney tissue. RESULTS: At baseline, urinary HB-EGF did not differ between ADPKD patients and healthy controls (P = .6), whereas a lower urinary EGF excretion was observed in ADPKD patients [18.6 (11.8-27.8)] compared with healthy controls [51.0 (34.9-65.4) µg/24 h, P < .001]. Urinary EGF was positively associated with baseline eGFR (R = 0.54, P < .001) and a lower EGF was strongly associated with a more rapid GFR decline, even when adjusted for ADPKD severity markers (ß = 1.96, P < .001), whereas HB-EGF was not. Expression of the EGFR, but not other EGFR-related receptors, was observed in renal cysts but was absent in non-ADPKD kidney tissue. Finally, unilateral nephrectomy resulted in a decrease of 46.4 (-63.3 to -17.6) % in urinary EGF excretion, alongside a decrease of 35.2 ± 7.2% in eGFR and 36.8 ± 6.9% in measured GFR (mGFR), whereas maximal mGFR (measured after dopamine induced hyperperfusion) decreased by 46.1 ± 7.8% (all P < .001). CONCLUSIONS: Our data suggest that lower urinary EGF excretion may be a valuable novel predictor for kidney function decline in patients with ADPKD.

Intraductal papillary neoplasms of the bile duct: a European retrospective multicenter observational study (EUR-IPNB study).

BACKGROUND/PURPOSE: Intraductal papillary neoplasm of the bile duct (IPNB) is a rare disease in Western countries. The main aim of this study was to characterize current surgical strategies and outcomes in the mainly European participating centers. METHODS: A multi-institutional retrospective series of patients with a diagnosis of IPNB undergoing surgery between 1 January 2010 and 31 December 2020 was gathered under the auspices of the European-African Hepato-Pancreato-Biliary Association. The textbook outcome (TO) was defined as a non-prolonged length of hospital stay plus the absence of any Clavien-Dindo grade at least III complications, readmission, or mortality within 90 postoperative days. RESULTS: A total of 28 centers contributed 85 patients who underwent surgery for IPNB. The median age was 66 years (55-72), 49.4% were women, and 87.1% were Caucasian. Open surgery was performed in 72 patients (84.7%) and laparoscopic in 13 (15.3%). TO was achieved in 54.1% of patients, reaching 63.8% after liver resection and 32.0% after pancreas resection. Median overall survival was 5.72 years, with 5-year overall survival of 63% (95% CI: 50-82). Overall survival was better in patients with Charlson comorbidity score 4 or less versus more than 4 ( P =0.016), intrahepatic versus extrahepatic tumor ( P =0.027), single versus multiple tumors ( P =0.007), those who underwent hepatic versus pancreatic resection ( P =0.017), or achieved versus failed TO ( P =0.029). Multivariable Cox regression analysis showed that not achieving TO (HR: 4.20; 95% CI: 1.11-15.94; P =0.03) was an independent prognostic factor of poor overall survival. CONCLUSIONS: Patients undergoing liver resection for IPNB were more likely to achieve a TO outcome than those requiring a pancreatic resection. Comorbidity, tumor location, and tumor multiplicity influenced overall survival. TO was an independent prognostic factor of overall survival.

Restoration of Bile Duct Injury of Donor Livers During Ex Situ Normothermic Machine Perfusion.

BACKGROUND: End-ischemic ex situ normothermic machine perfusion (NMP) enables assessment of donor livers prior to transplantation. The objective of this study was to provide support for bile composition as a marker of biliary viability and to investigate whether bile ducts of high-risk human donor livers already undergo repair during NMP. METHODS: Forty-two livers that were initially declined for transplantation were included in our NMP clinical trial. After NMP, livers were either secondary declined (n = 17) or accepted for transplantation (n = 25) based on the chemical composition of bile and perfusate samples. Bile duct biopsies were taken before and after NMP and assessed using an established histological injury severity scoring system and a comprehensive immunohistochemical assessment focusing on peribiliary glands (PBGs), vascular damage, and regeneration. RESULTS: Bile ducts of livers that were transplanted after viability testing during NMP showed better preservation of PBGs, (micro)vasculature, and increased cholangiocyte proliferation, compared with declined livers. Biliary bicarbonate, glucose, and pH were confirmed as accurate biomarkers of bile duct vitality. In addition, we found evidence of PBG-based progenitor cell differentiation toward mature cholangiocytes during NMP. CONCLUSIONS: Favorable bile chemistry during NMP correlates well with better-preserved biliary microvasculature and PBGs, with a preserved capacity for biliary regeneration. During NMP, biliary tree progenitor cells start to differentiate toward mature cholangiocytes, facilitating restoration of the ischemically damaged surface epithelium.

Acute and chronic histopathological findings in renal biopsies in COVID-19.

The dominant ICU admission diagnosis of COVID-19 patients is respiratory insufficiency, but 32-57% of hospitalized COVID-19 patients develop acute kidney injury (COVID-AKI). The renal histopathological changes accompanying COVID-AKI are not yet fully described. To obtain a detailed insight into renal histopathological features of COVID-19, we conducted a review including all studies reporting histopathological findings of diagnostic and postmortem kidney biopsies from patients with COVID-19 published between January 1, 2020, and January 31, 2021. A total of 89 diagnostic and 194 postmortem renal biopsies from individual patients in 39 published studies were investigated and were included in the analysis. In the diagnostic biopsy group, mean age was 56 years and AKI incidence was 96%. In the postmortem biopsy group, mean age was 69 years and AKI incidence was 80%. In the diagnostic biopsy group, the prevalence of acute glomerular diseases was 74%. The most common glomerular lesions were collapsing focal segmental glomerulosclerosis (c-FSGS) in 54% and thrombotic microangiopathy (TMA) in 9% of patients. TMA was also found in 10% of patients in the postmortem biopsy group. The most common acute tubular lesions was acute tubular necrosis (ATN) which was present in 87% of patients in the diagnostic and in 77% of patients in the postmortem biopsy group. Additionally, we observed a high prevalence of preexisting chronic lesions in both groups such as atherosclerosis and glomerulosclerosis. Histopathological changes in renal biopsies of COVID-19 patients show a heterogeneous picture with acute glomerular lesions, predominantly c-FSGS and TMA, and acute tubular lesions, predominantly ATN. In many patients, these lesions were present on a background of chronic renal injury.

Weak Expression of Terminal Complement in Active Antibody-Mediated Rejection of the Kidney.

Background: The role of the complement system in antibody-mediated rejection (ABMR) is insufficiently understood. We aimed to investigate the role of local and systemic complement activation in active (aABMR). We quantified complement activation markers, C3, C3d, and C5b-9 in plasma of aABMR, and acute T-cell mediated rejection (aTCMR), and non-rejection kidney transplant recipients. Intra-renal complement markers were analyzed as C4d, C3d, C5b-9, and CD59 deposition. We examined in vitro complement activation and CD59 expression on renal endothelial cells upon incubation with human leukocyte antigen antibodies. Methods: We included 50 kidney transplant recipients, who we histopathologically classified as aABMR (n=17), aTCMR (n=18), and non-rejection patients (n=15). Results: Complement activation in plasma did not differ across groups. C3d and C4d deposition were discriminative for aABMR diagnosis. Particularly, C3d deposition was stronger in glomerular (P<0,01), and peritubular capillaries (P<0,05) comparing aABMR to aTCMR rejection and non-rejection biopsies. In contrast to C3d, C5b-9 was only mildly expressed across all groups. For C5b-9, no significant difference between aABMR and non-rejection biopsies regarding peritubular and glomerular C5b-9 deposition was evident. We replicated these findings in vitro using renal endothelial cells and found complement pathway activation with C4d and C3d, but without terminal C5b-9 deposition. Complement regulator CD59 was variably present in biopsies and constitutively expressed on renal endothelial cells in vitro. Conclusion: Our results indicate that terminal complement might only play a minor role in late aABMR, possibly indicating the need to re-evaluate the applicability of terminal complement inhibitors as treatment for aABMR.

Persistent biliary hypoxia and lack of regeneration are key mechanisms in the pathogenesis of posttransplant nonanastomotic strictures.

BACKGROUND AND AIMS: Nonanastomotic biliary strictures (NAS) are a major cause of morbidity after orthotopic liver transplantation (OLT). Although ischemic injury of peribiliary glands (PBGs) and peribiliary vascular plexus during OLT has been associated with the later development of NAS, the exact underlying mechanisms remain unclear. We hypothesized that bile ducts of patients with NAS suffer from ongoing biliary hypoxia and lack of regeneration from PBG stem/progenitor cells. APPROACH AND RESULTS: Forty-two patients, requiring retransplantation for either NAS (n = 18), hepatic artery thrombosis (HAT; n = 13), or nonbiliary graft failure (controls; n = 11), were included in this study. Histomorphological analysis of perihilar bile ducts was performed to assess differences in markers of cell proliferation and differentiation in PBGs, microvascular density (MVD), and hypoxia. In addition, isolated human biliary tree stem cells (hBTSCs) were used to examine exo-metabolomics during in vitro differentiation toward mature cholangiocytes. Bile ducts of patients with NAS or HAT had significantly reduced indices of PBG mass, cellular proliferation and differentiation (mucus production, secretin receptor expression, and primary cilia), reduced MVD, and increased PBG apoptosis and hypoxia marker expression, compared to controls. Metabolomics of hBTSCs during in vitro differentiation toward cholangiocytes revealed a switch from a glycolytic to oxidative metabolism, indicating the need for oxygen. CONCLUSIONS: NAS are characterized by a microscopic phenotype of chronic biliary hypoxia attributed to loss of microvasculature, resulting in reduced proliferation and differentiation of PBG stem/progenitor cells into mature cholangiocytes. These findings suggest that persistent biliary hypoxia is a key mechanism underlying the development of NAS after OLT.

Nonmalignant portal vein thrombi in patients with cirrhosis consist of intimal fibrosis with or without a fibrin-rich thrombus.

BACKGROUND AND AIM: Portal vein thrombosis (PVT) is a common complication of cirrhosis. The exact pathophysiology remains largely unknown, and treatment with anticoagulants does not lead to recanalization of the portal vein in all patients. A better insight into the structure and composition of portal vein thrombi may assist in developing strategies for the prevention and treatment of PVT. APPROACH AND RESULTS: Sixteen prospectively and 63 retrospectively collected nonmalignant portal vein thrombi from patients with cirrhosis who underwent liver transplantation were included. Histology, immunohistochemistry, and scanning electron microscopy were used to assess structure and composition of the thrombi. Most recent CT scans were reanalyzed for thrombus characteristics. Clinical characteristics were related to histological and radiological findings. All samples showed a thickened, fibrotic tunica intima. Fibrin-rich thrombi were present on top of the fibrotic intima in 9/16 prospective cases and in 21/63 retrospective cases. A minority of the fibrotic areas stained focally positive for fibrin/fibrinogen (16% of cases), von Willebrand factor (VWF; 10%), and CD61 (platelets, 21%), while most of the fibrin-rich areas stained positive for those markers (fibrin/fibrinogen, 100%; VWF, 77%; CD61, 100%). No associations were found between clinical characteristics including estimated thrombus age and use of anticoagulants and presence of fibrin-rich thrombi. CONCLUSION: We demonstrate that PVT in patients with cirrhosis consists of intimal fibrosis with an additional fibrin-rich thrombus in only one-third of cases. We hypothesize that our observations may explain why not all portal vein thrombi in patients with cirrhosis recanalize by anticoagulant therapy.

Aggravation of fibrin deposition and microthrombus formation within the graft during kidney transplantation.

In kidney transplantation, microthrombi and fibrin deposition may lead to local perfusion disorders and subsequently poor initial graft function. Microthrombi are often regarded as donor-derived. However, the incidence, time of development, and potential difference between living donor kidneys (LDK) and deceased donor kidneys(DDK), remains unclear. Two open-needle biopsies, taken at preimplantation and after reperfusion, were obtained from 17 LDK and 28 DDK transplanted between 2005 and 2008. Paraffin-embedded sections were immunohistochemically stained with anti-fibrinogen antibody. Fibrin deposition intensity in peritubular capillaries(PTC) and glomeruli was categorized as negative, weak, moderate or strong and the number of microthrombi/mm2 was quantified. Reperfusion biopsies showed more fibrin deposition (20% to 100% moderate/strong, p < 0.001) and more microthrombi/mm2 (0.97 ± 1.12 vs. 0.28 ± 0.53, p < 0.01) than preimplantation biopsies. In addition, more microthrombi/mm2 (0.38 ± 0.61 vs. 0.09 ± 0.22, p = 0.02) and stronger fibrin intensity in glomeruli (28% vs. 0%, p < 0.01) and PTC (14% vs. 0%, p = 0.02) were observed in preimplantation DDK than LDK biopsies. After reperfusion, microthrombi/mm2 were comparable (p = 0.23) for LDK (0.09 ± 0.22 to 0.76 ± 0.49, p = 0.03) and DDK (0.38 ± 0.61 to 0.90 ± 1.11, p = 0.07). Upon reperfusion, there is an aggravation of microthrombus formation and fibrin deposition within the graft. The prominent increase of microthrombi in LDK indicates that they are not merely donor-derived.

Magnetic resonance imaging assessment of renal flow distribution patterns during ex vivo normothermic machine perfusion in porcine and human kidneys.

Acceptance criteria of deceased donor organs have gradually been extended toward suboptimal quality, posing an urgent need for more objective pre-transplant organ assessment. Ex vivo normothermic machine perfusion (NMP) combined with magnetic resonance imaging (MRI) could assist clinicians in deciding whether a donor kidney is suitable for transplantation. Aim of this study was to characterize the regional distribution of perfusate flow during NMP, to better understand how ex vivo kidney assessment protocols should eventually be designed. Nine porcine and 4 human discarded kidneys underwent 3 h of NMP in an MRI-compatible perfusion setup. Arterial spin labeling scans were performed every 15 min, resulting in perfusion-weighted images that visualize intrarenal flow distribution. At the start of NMP, all kidneys were mainly centrally perfused and it took time for the outer cortex to reach its physiological dominant perfusion state. Calculated corticomedullary ratios based on the perfusion maps reached a physiological range comparable to in vivo observations, but only after 1 to 2 h after the start of NMP. Before that, the functionally important renal cortex appeared severely underperfused. Our findings suggest that early functional NMP quality assessment markers may not reflect actual physiology and should therefore be interpreted with caution.

Comparison of renal histopathology and gene expression profiles between severe COVID-19 and bacterial sepsis in critically ill patients.

BACKGROUND: The mechanisms driving acute kidney injury (AKI) in critically ill COVID-19 patients are unclear. We collected kidney biopsies from COVID-19 AKI patients within 30 min after death in order to examine the histopathology and perform mRNA expression analysis of genes associated with renal injury. METHODS: This study involved histopathology and mRNA analyses of postmortem kidney biopsies collected from patients with COVID-19 (n = 6) and bacterial sepsis (n = 27). Normal control renal tissue was obtained from patients undergoing total nephrectomy (n = 12). The mean length of ICU admission-to-biopsy was 30 days for COVID-19 and 3-4 days for bacterial sepsis patients. RESULTS: We did not detect SARS-CoV-2 RNA in kidney biopsies from COVID-19-AKI patients yet lung tissue from the same patients was PCR positive. Extensive acute tubular necrosis (ATN) and peritubular thrombi were distinct histopathology features of COVID-19-AKI compared to bacterial sepsis-AKI. ACE2 mRNA levels in both COVID-19 (fold change 0.42, p = 0.0002) and bacterial sepsis patients (fold change 0.24, p < 0.0001) were low compared to control. The mRNA levels of injury markers NGAL and KIM-1 were unaltered compared to control tissue but increased in sepsis-AKI patients. Markers for inflammation and endothelial activation were unaltered in COVID-19 suggesting a lack of renal inflammation. Renal mRNA levels of endothelial integrity markers CD31, PV-1 and VE-Cadherin did not differ from control individuals yet were increased in bacterial sepsis patients (CD31 fold change 2.3, p = 0.0006, PV-1 fold change 1.5, p = 0.008). Angiopoietin-1 mRNA levels were downregulated in renal tissue from both COVID-19 (fold change 0.27, p < 0.0001) and bacterial sepsis patients (fold change 0.67, p < 0.0001) compared to controls. Moreover, low Tie2 mRNA expression (fold change 0.33, p = 0.037) and a disturbed VEGFR2/VEGFR3 ratio (fold change 0.09, p < 0.0001) suggest decreased microvascular flow in COVID-19. CONCLUSIONS: In a small cohort of postmortem kidney biopsies from COVID-19 patients, we observed distinct histopathological and gene expression profiles between COVID-19-AKI and bacterial sepsis-AKI. COVID-19 was associated with more severe ATN and microvascular thrombosis coupled with decreased microvascular flow, yet minimal inflammation. Further studies are required to determine whether these observations are a result of true pathophysiological differences or related to the timing of biopsy after disease onset.

Prolonged ex-vivo normothermic kidney perfusion: The impact of perfusate composition.

Normothermic machine perfusion (NMP) of donor kidneys provides the opportunity for improved graft preservation and objective pre-transplant ex-vivo organ assessment. Currently, a multitude of perfusion solutions exist for renal NMP. This study aimed to evaluate four different perfusion solutions side-by-side and determine the influence of different perfusate compositions on measured renal perfusion parameters. Porcine kidneys and blood were obtained from a slaughterhouse. Kidneys underwent NMP at 37°C for 7 hours, with 4 different perfusion solutions (n = 5 per group). Group 1 consisted of red blood cells (RBCs) and a perfusion solution based on Williams' Medium E. Group 2 consisted of RBCs, albumin and a balanced electrolyte composition. Group 3 contained RBCs and a medium based on a British clinical NMP solution. Group 4 contained RBCs and a medium used in 24-hour perfusion experiments. NMP flow patterns for solutions 1 and 2 were similar, solutions 3 and 4 showed lower but more stable flow rates. Thiobarbituric acid reactive substances were significantly higher in solution 1 and 4 compared to the other groups. Levels of injury marker N-acetyl-ß-D glucosaminidase were significantly lower in solution 2 in comparison with solution 3 and 4. This study illustrates that the perfusate composition during NMP significantly impacts the measured perfusion and injury parameters and thus affects the interpretation of potential viability markers. Further research is required to investigate the individual influences of principal perfusate components to determine the most optimal conditions during NMP and eventually develop universal organ assessment criteria.

Intrahepatic cholangiocarcinoma in a non-cirrhotic liver in a patient with homozygous ZZ alpha-1 antitrypsin deficiency.

Alpha-1 antitrypsin (AAT) deficiency, which is an under-recognised metabolic genetic disorder, is known to cause severe lung disease and liver cirrhosis in about 10%-15% of cases. Patients with AAT deficiency are at a higher risk for developing hepatocellular carcinoma, both in cirrhotic and in non-cirrhotic livers. In this case report, a 48-year-old woman with homozygous ZZ AAT deficiency presented with abdominal pain, and by imaging, an abnormal area in the liver was found. The initial differential diagnosis consisted of benign abnormalities but a malignancy could not be ruled out. Finally, this abnormality turned out to be an intrahepatic cholangiocarcinoma (iCCA) in a non-cirrhotic liver. Since this type of tumour has been very infrequently described to be associated with AAT deficiency, the question remains whether alpha-1 trypsin accumulation in the hepatocytes was responsible for the development of iCCA. However, other associated factors for developing an iCCA were ruled out.