OBJECTIVE: Mechanisms and clinical impact of portal microthrombosis featuring severe COVID-19 are unknown. Intrapulmonary vascular dilation (IPVD)-related hypoxia has been described in severe liver diseases. We hypothesized that portal microthrombosis is associated with IPVD and fatal respiratory failure in COVID-19.
METHODS: Ninety-three patients who died from COVID-19, were analysed for portal microvascular damage (histology), IPVD (histology and chest-computed tomography, CT), and hypoxemia (arterial blood gas). Seventeen patients who died from COVID-19-unrelated pneumonia served as controls. Vascular lesions and microthrombi were phenotyped for endothelial (vWF) and pericyte (αSMA/PDGFR-β) markers, tissue factor (TF), viral spike-protein and nucleoprotein (SP, NP), fibrinogen, platelets (CD41a). Viral particles in vascular cells were assessed by transmission electron microscopy (TEM). Cultured pericytes were infected with SARS-CoV-2 to measure TF expression and tubulisation of human pulmonary microvascular endothelial cells (HPMEC) was assessed upon vWF treatment.
RESULTS: IPVD was present in 16/66 COVID-19 patients with both liver and lung histology, with a younger age (62 vs 78yo), longer illness (25 vs 14 days), worsening hypoxemia (PaO2/FiO2 from 209 to 89), and more ventilatory support (63 vs 22%) compared to COVID-19/Non-IPVD. IPVD, absent in controls, were confirmed by chest-CT. COVID-19/IPVD liver histology showed portal microthrombosis in >82.5% of portal areas, with a thicker wall of αSMA/PDGFR-β+/ SP+/NP+ pericytes compared with COVID-19/Non-IPVD. Thrombosed portal venules correlated with αSMA+ area, whereas infected SP+/NP+ pericytes expressed TF. SARS-CoV-2 viral particles were observed in portal pericytes. In-vitro SARS-CoV-2 infection of pericytes up-regulated TF and induced endothelial cells to overexpress vWF, which expanded HPMEC tubules.
CONCLUSIONS: SARS-CoV-2 infection of liver pericytes elicits a local procoagulant response associated with extensive portal microthrombosis, IPVD and worsening respiratory failure in fatal COVID-19.
UNASSIGNED: Vascular involvement of the liver represents a serious complication of COVID-19 infection that must be considered in the work-up of patients with long-lasting and progressively worsening respiratory failure, as it may associate with the development of intrapulmonary vascular dilations. This clinical picture is associated with a pro-coagulant phenotype of portal venule pericytes, which is induced by SARS-CoV-2 infection of pericytes. Both observations provide a model that may apply, at least in part, to other vascular disorders of the liver, featuring obliterative portal venopathy, similarly characterized at the clinical level by development of hypoxemia and at the histological level, by phlebosclerosis and reduced caliber of the portal vein branches in the absence of cirrhosis. Moreover, our findings bring light to an as yet overlooked player of thrombosis pathophysiology, i.e. pericytes, which may provide novel therapeutic tools to halt prothrombotic mechanisms.

Comparative assessments of immunogenicity following different COVID-19 vaccines in patients with distinct liver diseases are lacking. SARS-CoV-2-specific T-cell and antibody responses were evaluated longitudinally after one to three vaccine doses, with long-term follow-up for COVID-19-related clinical outcomes.
A total of 849 participants (355 with cirrhosis, 74 with autoimmune hepatitis [AIH], 36 with vascular liver disease [VLD], 257 liver transplant recipients [LTRs] and 127 healthy controls [HCs]) were recruited from four countries. Standardised immune assays were performed pre and post three vaccine doses (V1-3).
In the total cohort, there were incremental increases in antibody titres after each vaccine dose (p <0.0001). Factors associated with reduced antibody responses were age and LT, whereas heterologous vaccination, prior COVID-19 and mRNA platforms were associated with greater responses. Although antibody titres decreased between post-V2 and pre-V3 (p = 0.012), patients with AIH, VLD, and cirrhosis had equivalent antibody responses to HCs post-V3. LTRs had lower and more heterogenous antibody titres than other groups, including post-V3 where 9% had no detectable antibodies; this was heavily influenced by intensity of immunosuppression. Vaccination increased T-cell IFNγ responses in all groups except LTRs. Patients with liver disease had lower functional antibody responses against nine Omicron subvariants and reduced T-cell responses to Omicron BA.1-specific peptides compared to wild-type. 122 cases of breakthrough COVID-19 were reported of which 5/122 (4%) were severe. Of the severe cases, 4/5 (80%) occurred in LTRs and 2/5 (40%) had no serological response post-V2.
After three COVID-19 vaccines, patients with liver disease generally develop robust antibody and T-cell responses to vaccination and have mild COVID-19. However, LTRs have sustained no/low antibody titres and appear most vulnerable to severe disease.
Standardised assessments of the immune response to different COVID-19 vaccines in patients with liver disease are lacking. We performed antibody and T-cell assays at multiple timepoints following up to three vaccine doses in a large cohort of patients with a range of liver conditions. Overall, the three most widely available vaccine platforms were immunogenic and appeared to protect against severe breakthrough COVID-19. This will provide reassurance to patients with chronic liver disease who were deemed at high risk of severe COVID-19 during the pre-vaccination era, however, liver transplant recipients had the lowest antibody titres and remained vulnerable to severe breakthrough infection. We also characterise the immune response to multiple SARS-CoV-2 variants and describe the interaction between disease type, severity, and vaccine platform. These insights may prove useful in the event of future viral infections which also require rapid vaccine development and delivery to patients with liver disease.

Porto-sinusoidal vascular disease (PSVD) is a novel nomenclature to describe non-cirrhotic portal hypertension and characteristic histology without portal vein thrombosis (PVT). It is a more inclusive definition than the previously well-recognized entity idiopathic non-cirrhotic portal hypertension. There is a paucity of data on PSVD patients.
A total of 33 patients diagnosed with PSVD and portal hypertension (PH) between 2005 and 2021 were included. Data were retrieved from electronic medical record system and analyzed.
Of the 33 patients, 6 (18%) occurred in post-transplant allograft liver. After a median follow-up of 96 months (interquartile range, IQR [52, 139]), 14 deaths occurred (42%), 4 directly related to decompensated liver disease. The Kaplan-Meier survival estimates at 1, 5, and 10 years were 94%, 87% and 58%. PVT occurred in 10 patients (30%). The Nelson-Aalen cumulative risk estimate for PVT at 1, 5 and 10 years were 16%, 25% and 48%. The median model for end-stage liver disease and Child-Pugh score at initial presentation were 8 (IQR [7-12]) and 5 [5-6], and increased to 13 [8, 18] and 7 [5, 8], respectively, at the end of follow-up. Of the 11 patients who presented with splenomegaly and no specific sign of PH, 7 (64%) developed varices and 3 (27%) ascites at a median follow-up of 100 months.
PSVD with PH is not a benign entity. Mortality, PVT and hepatic decompensation are common. Patients with PSVD must be closely monitored, including those who only have non-specific clinical signs (e.g., splenomegaly) of PH.

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OBJECTIVE: Recent non-malignant non-cirrhotic portal venous system thrombosis (PVT) is a rare condition. Among risk factors for PVT, cytomegalovirus (CMV) disease is usually listed based on a small number of reported cases. The aim of this study was to determine the characteristics and outcomes of PVT associated with CMV disease.
METHODS: We conducted a French multicenter retrospective study comparing patients with recent PVT and CMV disease (\"CMV positive\"; n = 23) to patients with recent PVT for whom CMV testing was negative (\"CMV negative\"; n = 53) or unavailable (\"CMV unknown\"; n = 297).
RESULTS: Compared to patients from the \"CMV negative\" and \"CMV unknown\" groups, patients from the \"CMV positive\" group were younger, more frequently had fever, and had higher heart rate, lymphocyte count and serum ALT levels (p ≤0.01 for all). The prevalence of immunosuppression did not differ between the 3 groups (4%, 4% and 6%, respectively). Extension of PVT was similar between the 3 groups. Thirteen out of 23 \"CMV positive\" patients had another risk factor for thrombosis. Besides CMV disease, the number of risk factors for thrombosis was similar between the 3 groups. Heterozygosity for the prothrombin G20210A gene variant was more frequent in \"CMV positive\" patients (22%) than in the \"CMV negative\" (4%, p = 0.01) and \"CMV unknown\" (8%, p = 0.03) groups. Recanalization rate was not influenced by CMV status.
CONCLUSIONS: In patients with recent PVT, features of mononucleosis syndrome should raise suspicion of CMV disease. CMV disease does not influence thrombosis extension nor recanalization. More than half of \"CMV positive\" patients have another risk factor for thrombosis, with a particular link to the prothrombin G20210A gene variant.
UNASSIGNED: Patients with cytomegalovirus (CMV)-associated portal venous system thrombosis have similar thrombosis extension and evolution as patients without CMV disease. However, patients with CMV-associated portal venous system thrombosis more frequently have the prothrombin G20210A gene variant, suggesting that these entities act synergistically to promote thrombosis.

While direct oral anticoagulants (DOACs) are increasingly used in patients with liver disease, safety data especially in advanced chronic liver disease (ACLD) are limited.
Liver disease patients receiving DOAC treatment (ACLD: n = 104; vascular liver disease: n = 29) or vitamin K antagonists (VKA)/low-molecular-weight heparin (LMWH; ACLD: n = 45; vascular: n = 13) between January 2010 and September 2020 were retrospectively included. Invasive procedures and bleeding events were recorded. Calibrated anti-Xa peak levels and thrombomodulin-modified thrombin generation assays (TM-TGAs) were measured in a subgroup of 35/28 DOAC patients.
Among patients receiving DOAC, 55 (41.3%) had advanced liver dysfunction (Child-Pugh-stage [CPS] B/C) and 66 (49.6%) had experienced decompensation. Overall, 205 procedures were performed in 60 patients and procedure-related bleedings occurred in 7 (11.7%) patients. Additionally, 38 (28.6%) patients experienced spontaneous (15 minor, 23 major) bleedings during a median follow-up of 10.5 (IQR: 4.0-27.8) months. Spontaneous bleedings in ACLD patients were more common in CPS-B/C (at 12 months: 36.9% vs CPS-A: 15.9%, subdistribution hazard ratio [SHR]: 3.23 [95% CI: 1.59-6.58], P < .001), as were major bleedings (at 12 months: 22.0% vs 5.0%, SHR: 5.82 [95% CI: 2.00-16.90], P < .001). Importantly, CPS (adjusted SHR: 4.12 [91% CI: 1.82-9.37], P < .001), but not the presence of hepatocellular carcinoma or varices, was independently associated with major bleeding during DOAC treatment. Additionally, ACLD patients experiencing bleeding had worse overall survival (at 12 months: 88.9% vs 95.0% without bleeding; P < .001). Edoxaban anti-Xa peak levels were higher in patients with CPS-B/C (345 [95% CI: 169-395] vs CPS-A: 137 [95% CI: 96-248] ng/mL, P = .048) and were associated with lower TM-TGA. Importantly, spontaneous bleeding rates were comparable to VKA/LMWH patients.
Anticoagulants including DOACs should be used with caution in patients with advanced liver disease due to a significant rate of spontaneous bleeding events.

Porto-sinusoidal vascular disease (PSVD) is a rare vascular liver disease of unknown etiology that causes portal hypertension. It usually affects young individuals and shortens live expectancy. The deregulated pathways involved in PSVD development are unknown and therefore we lack curative treatments. The purpose of this study was to integrate transcriptomic and clinical data by comprehensive network-based modeling in order to uncover altered biological processes in patients with PSVD.
We obtained liver tissue samples from 20 consecutive patients with PSVD and 21 sex- and age-matched patients with cirrhosis and 13 histologically normal livers (HNL) (initial cohort) and performed transcriptomic analysis. Microarray data were analyzed using weighted gene correlation network analysis to identify clusters of highly correlated genes differently expressed in patients with PSVD. We next evaluated the molecular pathways enriched in patients with PSVD and the core-related genes from the most significantly enriched pathways in patients with PSVD. Our main findings were validated using RNA sequencing in a different cohort of PSVD, cirrhosis and HNL (n = 8 for each group).
Patients with PSVD have a distinctive genetic profile enriched mainly in canonical pathways involving hemostasis and coagulation but also lipid metabolism and oxidative phosphorylation. Serpin family (SERPINC1), the apolipoproteins (APOA, APOB, APOC), ATP synthases (ATP5G1, ATP5B), fibrinogen genes (FGB, FGA) and alpha-2-macroglobulin were identified as highly connective genes that may have an important role in PSVD pathogenesis.
PSVD has a unique transcriptomic profile and we have identified deregulation of pathways involved in vascular homeostasis as the main pathogenic event of disease development.
Porto-sinusoidal vascular disease is a rare but life-shortening disease that affects mainly young people. Knowledge of the disrupted pathways involved in its development will help to identify novel therapeutic targets and new treatments. Using a systems biology approach, we identify that pathways regulating endothelial function and tone may act as drivers of porto-sinusoidal vascular disease.

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OBJECTIVE: Hepatobiliary phase (HBP) images can discriminate between benign and malignant liver lesions, but it is unclear if this approach can be used in patients with Budd-Chiari syndrome (BCS). Thus, we aimed to assess the diagnostic utility of HBP images in patients with BCS.
METHODS: This retrospective study included all patients admitted to our institution with a diagnosis of BCS and focal liver lesions on hepatobiliary contrast agent-enhanced MR imaging (HBCA-MRI) from 2000 to 2019. MR images were reviewed by 2 radiologists blinded to the diagnosis of the lesions. Patient and lesion characteristics were recorded, focusing on HBP imaging features.
RESULTS: Twenty-six patients (mean 35 ± 11 years old [13-65]; 21 women [81%] 35 ± 12 years old [13-65]; 5 men [19%] 36 ± 10 years old [19-44]) with 99 benign liver lesions and 12 hepatocellular carcinomas (HCCs) were analyzed. Patients with HCC were significantly older than those with benign lesions (mean 50 ± 10 vs. 33 ± 9 years old, p = 0.003), with higher alpha-fetoprotein (AFP) levels (3/4 [75%] vs. 1/22 [5%] with AFP >15 ng/ml, p <0.001). Homogeneous hypointense signals were identified on HBP in 14 lesions, including 12/12 (100%) HCCs, and 2/99 (2%) benign lesions (p <0.001). Most benign liver lesions showed either peripheral (n = 52/99 [53%]) or homogeneous hyperintensity (n = 23/99 [23%]) on HBP. Lesions with signal hypointensity on HBP in patients with AFP serum levels >15 ng/ml were all HCCs.
CONCLUSIONS: Most benign lesions showed homogeneous or peripheral hyperintensity on HBP images while all HCCs were homogeneously hypointense. HBP images are helpful to differentiate between benign lesions and HCCs and outperform other sequences. They should be systematically acquired for the characterization of focal lesions in patients with BCS.
BACKGROUND: Hepatobiliary phase imaging is an approach that has recently been shown to discriminate between benign and malignant lesions in the liver. However, it was not known whether this imaging approach could be used effectively in patients with Budd-Chiari syndrome. Herein, we have shown that hepatobiliary phase imaging appears to be useful for differentiating between benign and malignant liver lesions in patients with Budd-Chiari syndrome.

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