Plasma from patients with cirrhosis increases tissue plasminogen activator release from vascular endothelial cells in vitro

Elevation of Plasminogen Activator Inhibitor-1 promotes differentiation of Cancer Stem-like Cell state by Hepatitis C Virus infection

Plasminogen activator inhibitor-1 (PAI-1) is a critical factor that regulates protein synthesis and degradation. The increased PAI-1 levels are detectable in the serum of patients with chronic hepatitis C virus (HCV) liver disease. The differentiation state and motility of HCV-induced cancer stem-like cells (CSC) play a major role in severe liver disease progression. However, the role of PAI-1 in the pathological process of chronic liver diseases remains unknown. In this study, we determined how PAI-1 affects the differentiation of CSC state in hepatocytes upon HCV infection. We found that HCV infection induced the expression of PAI-1 while decreasing miR-30c expression in Huh7.5.1 cells. Similar results were obtained from isolated hepatocytes from humanized liver mice after HCV infection. Moreover, decreased miR-30c expression in HCV-infected hepatocytes was associated with the increased levels of PAI-1 mRNA and protein. Notably, the increased PAI-1 levels resulted in the activation of Protein Kinase B/AKT, a major mediator of cell proliferation, in HCV-infected hepatocytes along with the increased expression of CSC markers such as Human Differentiated Protein (CD) 133, Epithelial cell adhesion molecule (EpCAM), Octamer 4 (Oct4), Nanog, Cyclin D1, and MYC. Moreover, blockade of PAI-1 activity by miR-30c mimic and anti-PAI-1 mAb abrogated the AKT activation with decreased expression of CSC markers. Our findings suggest that HCV infection induces the CSC state via PAI-1-mediated AKT activation in hepatocytes. It implicates that the manipulation of PAI-1 activity could provide potential therapeutics to prevent the development of HCV-associated chronic liver diseases.IMPORTANCEThe progression of chronic liver disease by HCV infection is considered a major risk factor for hepatocellular carcinoma (HCC), one of the major causes of death from cancer. Recent studies have demonstrated that increased CSC properties in HCV-infected hepatocytes are associated with the progression of HCC. Since proteins and miRNAs production by HCV-infected hepatocytes can play various roles in physiological processes, investigating these factors can potentially lead to new therapeutic targets. However, the mechanism of HCV associated progression of hepatocytes to CSC remains unclear. Here we identify the roles of PAI-1 and miR-30c in the progression of CSC during HCV infection in hepatocytes. Our data shows that increased secretion of PAI-1 following HCV infection promotes this CSC state and activation of AKT. We report that the inhibition of PAI-1 by miR-30c mimic reduces HCV associated CSC properties in hepatocytes. Taken together, targeting this interaction of secreted PAI-1 and miR-30c in HCV-infected hepatocytes may provide a potential therapeutic intervention against the progression to chronic liver diseases and HCC.

Fibrinolysis status in the Budd-Chiari syndrome in China

Pathogenesis and clinical characteristics of the Budd-Chiari syndrome (BCS) in Asia are somewhat different from the ones observed in Western countries. Obstruction of the inferior vena cava (IVC) or of the hepatic veins is caused to a greater extent by membranous webs than by thrombosis. Impaired fibrinolysis has been found in European patients with BCS, but its status in Chinese patients with this condition is still unknown. To explore the characteristics of fibrinolysis in BCS patients in this country, we measured the euglobulin lysis time (ELT) for overall fibrinolysis and the plasma levels of five fibrinolytic components in 65 Chinese patients with BCS and 43 healthy controls. In patients, ELTs were slightly shorter than in controls (mean, 293 vs. 357 min, P < 0.02), tissue type plasminogen activator levels were higher than in controls (mean, 239 vs. 185 pg/ml, P < 0.01), and plasminogen activator inhibitor 1 levels were lower than in controls (mean, 1.43 vs. 1.73 ng/ml, P < 0.001). To explore BCS in more detail, we subgrouped the cases according to age, type of venous occlusion, Child-Pugh score, and thrombosis. As a result of this analysis, we found that young patients (age <30 years) had a longer ELT (mean, 440 min) than the older patient groups (30 ≤ age ≤ 44, 45 ≤ age ≤ 54, age>54 years; mean ELT = 242, 198, and 289 min, respectively, all P < 0.05). The independent hepatic vein occlusion subgroup showed a longer ELT (mean, 367 min) than the combined hepatic vein and IVC or the independent IVC occlusion subgroup (mean ELT = 233 and 260 min, both P < 0.05). ELT did not show significant differences between Child-Pugh class A and B subgroups (mean, 267 vs. 333 min, P > 0.05). ELT in the subgroup without thrombosis was shorter than in controls (mean, 288 vs. 358 min, P < 0.05), and in the subgroup with thrombosis, it was also slightly shorter than in controls, without reaching statistical significance (mean, 306 vs. 358 min, P > 0.05). By and large, overall fibrinolytic potential was slightly increased in Chinese patients with BCS in this study, but fibrinolysis differed according to its baseline characteristics. Compared with the one seen in BCS patients from Western countries, BCS in China exhibits certain special changes in fibrinolysis and we were able to explain some of these changes.

Increase of plasminogen activator inhibitor-1 and decrease of transforming growth factor-b1 in children with dengue haemorrhagic fever in Indonesia

Mortality in children with severe dengue haemorrhagic fever (DHF) in Indonesia is high. The origin of the elevated plasminogen activator inhibitor-1 (PAI-1) levels in these children is unclear. We measured PAI-1, transforming growth factor-β1 (TGF-β1), platelet counts, plasma leakage and liver function in 71 children with DHF (3-15 years old) and in 30 healthy children. We found that PAI-1 concentrations in children with DHF were significantly higher on admission than on Day 2. Circulating TGF-β1 concentrations on admission were significantly lower in DHF than in controls, but on Day 2 increased towards levels in controls. TGF-β1 and PAI-1 concentrations were not correlated on either day. PAI-1 was correlated with platelet count and serum albumin on admission, and with degree of pleural effusion. Liver function tests were mildly elevated but not correlated with PAI-1. In conclusion, elevated PAI-1 concentrations in DHF were associated with platelet counts and plasma leakage.

Increased PAI-1 plasma levels and risk of death from dengue: no association with the 4G/5G promoter polymorphism

Background

Dengue virus infected patients have high plasminogen activator inhibitor type I (PAI-1) plasma concentrations. Whether the insertion/deletion (4G/5G) polymorphism in the promotor region of the PAI-1 gene is associated with increased PAI-1 plasma concentrations and with death from dengue is unknown. We, therefore, investigated the relationship between the 4G/5G polymorphism and PAI-1 plasma concentrations in dengue patients and risk of death from dengue.

Methods

A total of 194 patients admitted to the Dr. Kariadi Hospital in Semarang, Indonesia, with clinical suspected severe dengue virus infection were enrolled. Blood samples were obtained on day of admission, days 1, 2 and 7 after admission and at a 1-month follow-up visit. Plasma concentrations of PAI-1 were measured using a sandwich ELISA kit. The PAI-1 4G/5G polymorphism was typed by allele-specific PCR analysis.

Results

Concentrations of PAI-1 on admission and peak values of PAI-1 during admission were higher than the values measured in healthy controls. Survival was significantly worse in patients with PAI-1 concentrations in the highest tertile (at admission: OR 4.7 [95% CI 0.9–23.8], peak value during admission: OR 6.3 [95%CI 1.3–30.8]). No association was found between the PAI-1 4G/5G polymorphism, and PAI-1 plasma concentrations, dengue disease severity and mortality from dengue.

Conclusion

These data suggest that the 4G/5G polymorphism has no significant influence on PAI-1 concentrations in dengue virus infected patients and is not associated with the risk of death from dengue. Other factors contributing to the variability of PAI-1 plasma concentrations in patients with dengue need to be explored.

Profound imbalance of pro-fibrinolytic and anti-fibrinolytic factors (tissue plasminogen activator and plasminogen activator inhibitor type 1) and severe bleeding diathesis in a patient with cirrhosis

A 49-year-old male with alcoholic cirrhosis suffered several spontaneous, life-threatening, deep muscle bleeding episodes. Laboratory evaluation indicated excessive fibrinolysis with low plasminogen, low alpha2-antiplasmin, undetectable plasminogen activator inhibitor type 1 (PAI-1) activity, high tissue plasminogen activator (t-PA) activity and high t-PA antigen. Treatment with oral anti-fibrinolytic agents prevented further bleeding episodes. Decompensated cirrhosis eventually necessitated orthotopic liver transplantation. Post-operatively, the patient did not require oral anti-fibrinolytic agents, and there were no significant bleeding events. Circulating PAI-1 activity, t-PA activity and antigen normalized by 3 months post transplant. In short, the profound bleeding diathesis, as well as the imbalance in t-PA and PAI-1 levels, corrected after liver transplantation. Recognition of such patients is important, because the bleeding diathesis is an indication rather than a contraindication for orthotopic liver transplantation.

Hepatic clearance of tissue-type plasminogen activator and plasma kallikrein in experimental liver fibrosis

We have previously shown that tissue-type plasminogen activator (tPA) and rat plasma kallikrein (RPK) share a common, but not unique, pathway for liver clearance.

AIM

To evaluate the hepatic clearance of both proteases in experimental liver fibrosis.

METHODS

The hepatic clearance of these proteases was studied in porcine serum-induced liver fibrosis using the isolated and perfused rat liver model. To better interpret the results, we also studied four other experimental groups: the turpentine oil-induced acute-phase response (AP group), AP group followed by GdCl3 administration (AP/Gd group), CCl4-induced cirrhosis (CCl4 group) and normal group.

RESULTS

The tPA clearance decreased significantly by both fibrotic and cirrhotic rat livers whereas the RPK clearance was not altered by the fibrotic rat liver. The hepatic clearance of tPA was reduced in the AP and AP/Gd groups; on the other hand, RPK clearance was increased in the AP group and, interestingly, this effect was neutralized by concomitant GdCl3 administration.

CONCLUSIONS

We observed that tPA and RPK clearances were affected differently by fibrosis as well as by different stimuli of the acute-phase response, despite the fact that they share a common hepatic clearance mechanism in normal livers, and they were equally affected in cirrhosis.