Porto-pulmonary hypertension exacerbated by platelet transfusion in a patient with ADAMTS13 deficiency

Altered von Willebrand Factor and ADAMTS13 Levels in Children With Cirrhosis and Extrahepatic Portal Hypertension

BACKGROUND/AIM

This study was concerned with whether vWF (von Willebrand factor) and a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13) has altered in patients with cirrhosis and extrahepatic portal hypertension (EPH). We aimed to investigate changes to vWF and ADAMTS13 in children with cirrhosis and EPH.

PATIENTS AND METHODS

This study was conducted between January and October 2019 with both cirrhosis and EPH patients and with healthy volunteers. The von Willebrand factor antigen (vWF:Ag), von Willebrand Ristocetin cofactor (vWF:RCo), and ADAMTS13 antigen and activity were studied.

RESULTS

Twenty-eight children with cirrhosis, 16 children with EPH, and 20 healthy controls were included in the study. vWF:Ag and vWF:RCo levels were higher in patients with cirrhosis than in healthy controls (171.65±101.67 vs. 85.86±30.58, P<0.01 and 121.62±55.83 vs. 61.52±27.03, P<0.01, respectively). vWF:Ag and vWF:RCo levels were higher in patients with EPH than in healthy controls (133.93±80.13 vs. 85.86±30.58, P<0.01 and 103.18±58.55 vs. 61.52±27.03, P=0.02, respectively). The ADAMTS13 antigen and activity levels were lower in patients with cirrhosis than in healthy controls (0.58±0.23 vs. 0.97±0.15, P<0.01 and 49.91±22.43 vs. 86.51±22.07, P=0.02, respectively). The ADAMTS13 antigen and activity levels were lower in patients with EPH than in healthy controls (0.69±0.11 vs. 0.97±0.15, P=0.03; and 68.50±13.29 vs. 86.51±22.07, P=0.02, respectively). The increase in vWF and the decrease in ADAMTS13 were more pronounced in cirrhotic patients with autoimmune hepatitis (AIH) than in non-AIH patients.

CONCLUSIONS

While levels of vWF:Ag and vWF:RCo increased in children with cirrhosis and EPH, levels of the ADAMTS13 antigen and ADAMTS13 activity decreased. These alterations were more pronounced in patients with AIH-derived cirrhosis.

Plasma Von Willebrand Factor Levels Predict Survival in COVID-19 Patients Across the Entire Spectrum of Disease Severity

Background: Characterization of reticulo-endothelial activation in COVID-19 may guide treatment. Objectives: To assess reticulo-endothelial activation and its correlation with disease severity and death in patients across the entire spectrum of COVID-19 severity. Methods: Consecutive hospitalized COVID-19 patients were studied, with similar number of patients in each disease severity category. Baseline serum ferritin, sCD163 (macrophage activation markers) and plasma von Willebrand factor (VWF) antigen (endothelial activation marker) levels were studied. Clinical parameters and plasma D-dimer levels were also studied. The study parameters were correlated with COVID-19 severity and survival. Results: The 143 patients (104 males [80%], age 54 [42 – 65] years, median [inter-quartile range]) presented 4 (3—7) days after symptom onset. Thirty-four patients had mild disease, 36 had moderate disease, 36 had severe disease and 37 had critical disease at baseline. With increasing COVID-19 severity, ferritin, sCD163, VWF and D-dimer levels significantly increased at baseline, however, 139 patients had normal sCD163 levels. Of the reticulo-endothelial markers, VWF level independently correlated with COVID-19 severity and with survival. VWF level > 332.6 units/dl correlated with COVID-19 severity (odds ratio [OR]: 2.77 [95% confidence interval (C.I): 1.1 – 6.99], p value: 0.031) and in-hospital death (OR [95% CI]: 29.28 [5.2 – 165], p value < 0.001). Conclusions: Reticulo-endothelial activation markers increased incrementally with worsening COVID-19 severity. Baseline endothelial activation marker (VWF), and not macrophage activation markers, independently correlated with COVID-19 severity and death.

Impact of liver damage on blood-borne variables and pulmonary hemodynamic responses to hypoxia and hyperoxia in anesthetized rats

BACKGROUND

Liver disorders may be associated with normal pulmonary hemodynamic, hepatopulmonary syndrome (HPS), or portopulmonary hypertension (POPH). In this study, we aimed to investigate the effect of the severity of liver dysfunctions on blood-borne variables, and pulmonary hemodynamic during repeated ventilation with hyperoxic and hypoxic gases.

METHODS

Female Sprague Dawley rats were assigned into four groups of Sham (n = 7), portal vein ligation (PPVL, n = 7), common bile duct ligation (CBDL, n = 7), and combination of them (CBDL+ PPVL, n = 7). Twenty-eight days later, right ventricular systolic pressure (RVSP) and systemic blood pressure were recorded in anesthetized animals subjected to repeated maneuvers of hyperoxia (O₂ 50%) and hypoxia (O₂ 10%). Besides, we assessed blood parameters and liver histology.

RESULTS

Liver histology score, liver enzymes, WBC and plasma malondialdehyde in the CBDL+PPVL group were higher than those in the CBDL group. Also, the plasma platelet level in the CBDL+PPVL group was lower than those in the other groups. On the other hand, the serum estradiol in the CBDL group was higher than that in the CBDL+PPVL group. All the above parameters in the PPVL group were similar to those in the Sham group. During ventilation with hyperoxia gas, RVSP in the CBDL+PPVL group was higher than the ones in the other groups, and in the CBDL group, it was more than those in the PPVL and Sham groups. Hypoxic pulmonary vasoconstriction (HPV) was not detected in both CBDL+PPVL and CBDL groups, whereas, it retained in the PPVL group.

CONCLUSION

Severe liver damage increases RVSP in the CBDL+PPVL group linked to the high level of ROS, low levels of serum estradiol and platelets or a combination of them. Furthermore, the high RVSP at the noted group could present a reliable animal model for POPH in female rats.

Rodenticidal hepatotoxicity: Raised plasma Von Willebrand factor levels predict in-hospital survival and preliminary report of the outcome of Von Willebrand factor reducing management protocol

BACKGROUND

High Von Willebrand factor (VWF) levels may predispose to multi-organ failure in acute liver failure (ALF). In rodenticide-induced hepatotoxicity patients, we analyzed if plasma VWF levels predicted survival and also the outcome of VWF lowering by N-acetyl cysteine (NAC), fresh frozen plasma (FFP) infusions, and plasma exchange (PLEX).

METHODS

We retrospectively analyzed prospectively collected data. Hepatotoxicity was classified as uncomplicated acute hepatitis (UAH), acute liver injury (ALI), and ALF. ALF patients, if not opting for liver transplantation, had PLEX and NAC; ALI patients received NAC ± FFP (PLEX, if worsening); UAH patients had NAC. Plasma VWF antigen was measured (normal, 50% to 150%). In-hospital survival was analyzed as discharged alive or died/discharged in a terminal condition (poor outcome).

RESULTS

Twenty-four consecutive rodenticide-induced hepatotoxicity patients (UAH in 1, ALI in 20, ALF in 3) from December 2017 to January 2019 were studied. Baseline VWF levels were 153%, 423 (146-890)% median (range), and 448 (414-555)% in UAH, ALI, ALF patients; model for end-stage liver disease (MELD) scores were 11, 24 (12-38), 36 (32-37) and in-hospital survival rates were 100%, 85%, 67%, respectively. VWF levels were higher in patients with poor outcome (555 [512-890]%) than in those discharged alive (414 [146-617]%) (p-value = 0.04). The area under the receiver operating curve of the VWF level, MELD score, and sequential organ failure assessment score to predict survival was 0.92, 0.84, and 0.66, respectively. Of 4 patients meeting criteria for liver transplantation (none had transplantation), 3 (75%) survived.

CONCLUSIONS

High VWF levels predict poor outcome in rodenticide-induced hepatotoxicity. VWF reduction may be useful in such patients.

Systematic review: role of elevated plasma von-Willebrand factor as predictor of mortality in patients with chronic liver disease

In this systematic review, we aimed to assess role of plasma von-Willebrand factor (vWF), an endothelial activation marker, as prognostic marker in patients with chronc liver disease [cirrhosis and acute-on-chronic liver failure (ACLF)]. We searched published databases using predefined keywords to identify all studies up to June 2018, in which plasma vWF (antigen or activity assay) was used as prognostic marker predicting mortality in patients with chronic liver disease. Relevant extracted data from selected studies were narratively summarized. The individual study's area under ROC curve for plasma vWF as a predictor of mortality was pooled and meta-analyzed. Six studies (cirrhosis: 5; ACLF: 1) with an aggregate data of 765 patients (cirrhosis: 715 patients; ACLF: 50 patients) were included. Baseline plasma vWF-antigen was an independent predictor of medium-term mortality in patients with cirrhosis (summary area under the curve: 0.74; 95% confidence interval: 0.70-0.79) with an optimal cutoff of 318% (216-390%; median, range) over a period of 25.6 months (23.6-33 months). Plasma vWF also predicted short-term (over 7 days) mortality in patients with ACLF. Plasma vWF levels correlated with Child's score, model for end-stage liver disease (MELD) score and hepatic venous pressure gradient and performed as well as MELD score in predicting mortality in patients with cirrhosis and ACLF. Baseline plasma vWF level predicts mortality over a medium term (1-3 years) in cirrhosis and over a short term (1 week) in ACLF patients. The marked elevation of baseline plasma vWF levels in ACLF patients was associated with drastic truncation of survival when compared with cirrhosis patients.

Plasma von Willebrand factor levels predict in-hospital survival in patients with acute-on-chronic liver failure

BACKGROUND AND AIMS

Circulating levels of von Willebrand factor (vWF) predict mortality in patients with cirrhosis. We hypothesized that systemic inflammation in acute-on-chronic liver failure (ACLF) will stimulate endothelium, increase vWF levels, and promote platelet microthrombi causing organ failure.

METHODS

In this prospective study, we correlated plasma vWF levels with organ failure, liver disease severity, sepsis, and systemic inflammatory response syndrome (SIRS) and also analyzed if vWF levels predicted in-hospital composite poor outcome (i.e. death/discharged in terminal condition/liver transplantation) in consecutive ACLF patients.

RESULTS

Twenty-one of the 50 ACLF patients studied had composite poor outcome. ACLF patients had markedly elevated vWF antigen and activity (sevenfold and fivefold median increase, respectively) on days 1 and 3. Median ratio of vWF to a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13 (ADAMTS13) activity on day 1 was significantly higher in ACLF patients (11.2) compared to 20 compensated cirrhosis patients (3.3) and healthy volunteers (0.9). On day 1, area under ROC curve (AUROC) to predict composite poor outcome of hospital stay for ACLF patients for vWF antigen, vWF activity, and model for end-stage liver disease (MELD) score were 0.63, 0.68, and 0.74, respectively. vWF activity correlated better with liver disease severity (MELD score, ACLF grade) and organ failure (Sequential Organ Failure Assessment [SOFA] score) than vWF antigen; in contrast, neither vWF antigen nor activity correlated with platelet count, sepsis, or SIRS.

CONCLUSIONS

vWF levels are markedly elevated, correlate with organ failure, and predict in-hospital survival in ACLF patients. This data provides a mechanistic basis for postulating that vWF-reducing treatments such as plasma exchange may benefit ACLF patients.

Update on ADAMTS13 and VWF in cardiovascular and hematological disorders

Endothelial cells (EC) respond to injury by releasing numerous factors, including von Willebrand factor (VWF). High circulating levels of unusually large VWF multimers (UL-VWFM) have strong procoagulant activity and facilitate platelet adhesion and aggregation by interacting with platelets after an acute event superimposed on peripheral arterial disease and coronary artery disease. ADAMTS13-a disintegrin-like metalloproteinase with thrombospondin motif type 1 member 13-regulates a key physiological process of coagulation in the circulation by cleaving VWF multimers into small, inactive fragments. Low levels of ADAMTS13 in the blood may play a role in cardiovascular and hematological disorders, and clarifying its role may help improve disease management. The genetic, pharmacological, physiological, and pathological aspects related to ADAMTS13/VWF have been extensively investigated. Here, we provide an update on recent findings of the relationship between ADAMTS13 and hematological/cardiovascular disorders, including thrombotic thrombocytopenic purpura, arterial thrombosis, thrombotic microangiopathy, myocardial infarction, ischemic stroke, heart failure, and hypertension.

Relevance of ADAMTS13 to liver transplantation and surgery

A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) specifically cleaves unusually-large von Willebrand factor (VWF) multimers under high shear stress, and down-regulates VWF function to form platelet thrombi. Deficiency of plasma ADAMTS13 activity induces a life-threatening systemic disease, termed thrombotic microangiopathy (TMA) including thrombotic thrombocytopenic purpura (TTP). Children with advanced biliary cirrhosis due to congenital biliary atresia sometimes showed pathological features of TMA, with a concomitant decrease of plasma ADAMTS13 activity. Disappearance of their clinical findings of TTP after successful liver transplantation suggested that the liver is a major organ producing plasma ADAMTS13. In situ hybridization analysis showed that ADAMTS13 was produced by hepatic stellate cells. Subsequently, it was found that ADADTS13 was not merely responsible to development of TMA and TTP, but also related to some kinds of liver dysfunction after liver transplantation. Ischemia-reperfusion injury and acute rejection in liver transplant recipients were often associated with marked decrease of ADAMTS13 and concomitant formation of unusually large VWF multimers without findings of TMA/TTP. The similar phenomenon was observed also in patients who underwent hepatectomy for liver tumors. Imbalance between ADAMTS13 and VWF in the hepatic sinusoid might cause liver damage due to microcirculatory disturbance. It can be called as “local TTP like mechanism” which plays a crucial role in liver dysfunction after liver transplantation and surgery.

Idiopathic Non-Cirrhotic Intrahepatic Portal Hypertension (NCIPH)-Newer Insights into Pathogenesis and Emerging Newer Treatment Options

Chronic microangiopathy of portal venules results in idiopathic non-cirrhotic intrahepatic portal hypertension (NCIPH). Recent data suggest a role for vasoactive factors of portal venous origin in the pathogenesis of this 'pure' vasculopathy of the liver. Enteropathies (often silent), are an important 'driver' of this disease. NCIPH is under-recognized and often mis-labeled as cryptogenic cirrhosis. Liver biopsy is needed to prove the diagnosis of NCIPH. In these patients, with advancing disease and increased porto-systemic shunting, the portal venous vasoactive factors bypass the liver filter and contribute to the development of pulmonary vascular endothelial disorders-porto-pulmonary hypertension and hepato-pulmonary syndrome as well as mesangiocapillary glomerulonephritis. Prognosis in NCIPH patients is determined by presence, recognition and management of associated disorders. With better understanding of the pathogenesis of NCIPH, newer treatment options are being explored. Imbalance in ADAMTS 13 (a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13): vWF (von-Willebrand factor) ratio is documented in NCIPH patients and may have a pathogenic role. Therapeutic interventions to correct this imbalance may prove to be important in the management of NCIPH.

ADAMTS13 deficiency, despite well-compensated liver functions in patients with noncirrhotic portal hypertension

BACKGROUND

We have reported A disintegrin and metalloprotease with thrombospondin type 1 motif, member 13 (ADAMTS13) deficiency in noncirrhotic intrahepatic portal hypertension (NCIPH) patients of European origin with preserved liver function. We aimed to study ADAMTS13-von Willebrand factor (vWF) imbalance in Indian patients with NCIPH.

METHODS

Twenty-nine cases with NCIPH [22 males; 29 years (13-58); Child's A, 23; B, 6], 22 disease controls with cryptogenic chronic liver disease [15 males; 46 years (18-74); Child's A, 9; B, 9; C, 4] and 17 healthy controls [14 males; 32 years (27-45)] were enrolled in the study. We measured ADAMTS13 antigen and activity (by collagen binding assay (CBA) and by fluorescence resonance energy transfer [FRET] assay), and vWF antigen levels in plasma of study patients.

RESULTS

ADAMTS13 activity by CBA in NCIPH patients (32 %, 5 % to 100 %; median, range; p-value <0.001) and disease controls (36 %, 5 % to 144 %; p = 0.001) was significantly lower than in healthy controls (87 %; 60 % to 148 %). ADAMTS13 antigen and activity by FRET assay were also lower in cases and disease controls. ADAMTS13 activity (by CBA) to antigen ratio was lower in NCIPH and disease controls than in healthy controls. Of 29 NCIPH patients, 3 (all in Child's A) had severe ADAMTS13 deficiency (<10 % ADAMTS13 activity), and 8 (Child's A, 7; B, 1) had moderate ADAMTS13 deficiency (10 % to 25 % activity). Conversely, vWF antigen and vWF:ADAMTS13 ratio were higher in patients with NCIPH and in disease controls than in healthy controls.

CONCLUSIONS

This study validates the finding of ADAMTS13 deficiency in NCIPH despite preserved liver functions in an Indian population suggesting its involvement in pathogenesis of NCIPH.