Thrombospondin Type-1 Motif Research Articles

Adamts9 is required for the development of primary ovarian follicles and maintenance of female sex in zebrafish†.

Previous studies have suggested that adamts9 (a disintegrin and metalloprotease with thrombospondin type-1 motifs, member 9), an extracellular matrix (ECM) metalloprotease, participates in primordial germ cell (PGC) migration and is necessary for female fertility. In this study, we found that adamts9 knockout (KO) led to reduced body size, and female-to-male sex conversion in late juvenile or adult zebrafish; however, primary sex determination was not affected in early juveniles of adamts9 KO. Overfeeding and lowering the rearing density rescued growth defects in female adamts9 KO fish but did not rescue defects in ovarian development in adamts9 KO. Delayed PGC proliferation, significantly reduced number and size of Stage IB follicles (equivalent to primary follicles) in early juveniles of adamts9 KO, and arrested development at Stage IB follicles in mid- or late-juveniles of adamts9 KO are likely causes of female infertility and sex conversion. Via RNAseq, we found significant enrichment of differentially expressed genes involved in ECM organization during sexual maturation in ovaries of wildtype fish; and significant dysregulation of these genes in adamts9 KO ovaries. RNAseq analysis also showed enrichment of inflammatory transcriptomic signatures in adult ovaries of these adamts9 KO. Taken together, our results indicate that adamts9 is critical for development of primary ovarian follicles and maintenance of female sex, and loss of adamts9 leads to defects in ovarian follicle development, female infertility, and sex conversion in late juveniles and mature adults. These results show that the ECM and extracellular metalloproteases play major roles in maintaining ovarian follicle development in zebrafish.

Ratio of von Willebrand factor to ADAMTS13 is a useful predictor of esophagogastric varices progression after sustained virologic response in patients with hepatitis C virus-related liver cirrhosis.

Esophagogastric varices (EGV) are a serious complication of hepatitis C virus (HCV)-related liver cirrhosis (HCV-LC). In most cases, portal hypertension improves after a sustained virologic response (SVR) is achieved with direct-acting antiviral (DAA) treatment; however, in some cases, EGV exacerbation occurs after HCV elimination. We investigated whether von Willebrand factor (VWF) and a disintegrin-like metalloproteinase with thrombospondin type-1 motif 13 (ADAMTS13) can predict EGV progression with HCV-LC after SVR achievement. This retrospective study enrolled 47 patients with HCV-LC who achieved an SVR after DAA treatment. Eighteen patients experienced EGV progression after the SVR was achieved (EGV progression group). Twenty-nine patients did not experience EGV progression after the SVR was achieved (non-EGV progression group). Plasma VWF antigen levels and ADAMTS13 activity were measured the day before DAA treatment. The EGV progression group had significantly higher plasma VWF antigen levels (p=0.00331) and VWF-to-ADAMTS13 ratios (p=0.000249) than the non-EGV progression group. Multivariate logistic regression models found that a VWF-to-ADAMTS13 ratio >2.3 was the only risk factor for EGV progression after the SVR was achieved (hazard ratio [HR], 18.4; 95% confidence interval [CI], 3.08-109; p=0.00138). During the observation period, patients with a VWF-to-ADAMTS13 ratio >2.3 had a significantly higher cumulative incidence of EGV progression after SVR achievement than patients with a VWF-to-ADAMTS13 ratio ≤2.3 (HR, 6.4; 95% CI, 1.78-22.96; p=0.0044). The VWF-to-ADAMTS13 ratio before DAA treatment for HCV could predict EGV progression after SVR achievement.

ADAMTS-13: A Prognostic Biomarker for Portal Vein Thrombosis in Japanese Patients with Liver Cirrhosis.

Portal vein thrombosis (PVT), one of the most prevalent hepatic vascular conditions in patients with liver cirrhosis (LC), is associated with high mortality rates. An imbalance between a disintegrin-like metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS-13) enzyme and von Willebrand factor (VWF) is responsible for hypercoagulability, including spontaneous thrombus formation in blood vessels. Herein, we aimed to identify potential prognostic and diagnostic biomarkers in Japanese patients with LC and PVT. In total, 345 patients were divided into two groups: 40 patients who developed PVT (PVT group) and 305 who did not develop PVT (NPVT group). Among the 345 patients with LC, 81% (279/345) were deemed ineligible due to the presence of preventive comorbidities, active or recent malignancies, and organ dysfunction. The remaining 66 patients were divided into two groups: the PVT group (n = 33) and the NPVT group (n = 33). Plasma ADAMTS-13 activity (ADAMTS-13:AC) and the vWF antigen (VWF:Ag) were measured using enzyme-linked immunosorbent assays. Contrast-enhanced, three-dimensional helical computed tomography (CT) was used to detect and characterize PVT. ADAMTS-13:AC was significantly lower in the PVT group than in the NPVT group. No significant differences in plasma vWF:Ag or liver stiffness were observed between the two groups. ADAMTS-13:AC of <18.8 was an independent risk factor for PVT on multivariate analyses (odds ratio: 1.67, 95% confidence interval: 1.21-3.00, p < 0.002). The receiver operating characteristic analysis of ADAMTS-13:AC revealed an area under the curve of 0.913 in PVT detection. Patients with PVT having ADAMTS-13:AC ≥18.8 (n = 17) had higher albumin levels and better prognoses than those with ADAMTS-13:AC <18.8 (n = 16). No significant correlations of ADAMTS-13:AC levels with either fibrin degradation product or D-dimer levels were observed. ADAMTS-13:AC levels could be potential diagnostic and prognostic biomarkers for PVT in Japanese patients with LC.

Hemoperfusion and plasmapheresis in the intensive care unit

In addition to kidney replacement procedures, several other extracorporeal procedures are employed in the intensive care unit. Hemoperfusion with activated charcoal was the predominant treatment used for removal of toxins from the 1970s until the millennium. Nowadays, this treatment does no longer play aclinically meaningful role as even strongly protein-bound toxins can be removed by effective dialysis procedures in case poisoning. The concept of acytokine adsorber was introduced 10years ago, which is directed towards withstanding the cytokine storm. Despite negative data from prospective randomized controlled studies, its use is steadily increasing in Germany. Atotally different treatment concept is the biomimetic pathogen adsorber, which removes bacteria, viruses and fungi from the bloodstream by binding to immobilized heparin. Whether this rapid reduction of the pathogen load translates into an improvement of clinically relevant endpoints is unclear, as prospective randomized controlled studies are lacking. For the early hours of septic shock a very old procedure, plasmapheresis, has recently regained interest. The results of two large randomized controlled studies in this setting from Europe and Canada will become available in 2025/2026. The rationale to use plasma exchange in early sepsis is that this procedure not only removes cytokines but also replenishes reduced levels of protective factors, such as angiopoietin‑1, adisintegrin and metalloproteinase with a thrombospondin type1 motif, member13 (ADAMTS-13) and proteinC, if fresh plasma is used as exchange fluid. All afore mentioned procedures do not only have a different mode of action but are also used at seperate time points of bloodstream infections and/or sepsis.

The Ratio of von Willebrand Factor Antigen to ADAMTS13 Activity: Usefulness as a Prognostic Biomarker in Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) has a high risk of short-term mortality. A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) is a metalloproteinase that specifically cleaves multimeric von Willebrand factor (VWF). Imbalance between ADAMTS13 and VWF is associated with portal hypertension, which induces ACLF development. A previous study reported that ADAMTS13 activity (ADAMTS13:AC) and VWF antigen (VWF:Ag) are predictive biomarkers of ACLF development in patients with cirrhosis. This study investigated the changes in ADAMTS13:AC and VWF:Ag levels from before to after the development of ACLF to determine their usefulness as a prognostic biomarker in patients with ACLF. In total, 101 patients with cirrhosis were enrolled in this study. The level of ADAMTS13:AC and VWF:Ag was determined by an enzyme-linked immunosorbent assay. Cox proportional hazard regression analysis was conducted to determine independent prognostic factors for patients with liver cirrhosis in the post-ACLF group. ADAMTS13:AC levels gradually decreased in the order of non-ACLF group, pre-ACLF group, and finally post-ACLF group. VWF:Ag and the ratio of VWF:Ag to ADAMTS13:AC (VWF:Ag/ADAMTS13:AC) levels gradually increased in the order of non-ACLF group, pre-ACLF group, followed by post-ACLF group. VWF:Ag/ADAMTS13:AC and CLIF-C ACLF scores were associated with prognosis in the post-ACLF group in multivariate analysis. The cumulative survival of the post-ACLF group was significantly lower for patients with high VWF:Ag/ADAMTS13:AC (>9) compared with those with low VWF:Ag/ADAMTS13:AC (≤9) (HR: 10.72, 95% confidence interval: 1.39-82.78, p < 0.05). The VWF:Ag/ADAMTS13:AC increased according to the progression of ACLF in patients with cirrhosis and predicted prognosis in patients with cirrhosis with ACLF.

Plasma markers of COVID-19 severity: a pilot study

BackgroundSARS-CoV-2 infected patients show heterogeneous clinical presentations ranging from mild symptoms to severe respiratory failure and death. Consequently, various markers reflect this wide spectrum of disease presentations.MethodsOur pilot cohort included moderate (n = 10) and severe (n = 10) COVID-19 patients, and 10 healthy controls. We determined plasma levels of nine acute phase proteins (APPs) by nephelometry, and full-length (M65), caspase-cleaved (M30) cytokeratin 18, and ADAMTS13 (a disintegrin-like and metalloprotease with thrombospondin type-1 motif 13) by ELISA. In addition, we examined whole plasma N-glycosylation by capillary gel electrophoresis coupled to laser-induced fluorescence detection (CGE-LIF).ResultsWhen compared to controls, COVID-19 patients had significantly lower concentrations of ADAMTS13 and albumin (ALB) but higher M30, M65, α1-acid glycoprotein (AGP), α1-antitrypsin (AAT), ceruloplasmin (CP), haptoglobin (HP), and high-sensitivity C-reactive protein (hs-CRP). The concentrations of α1-antichymotrypsin (ACT), α2-macroglobulin (A2MG) and serum amyloid A (SAA) proteins did not differ. We found significantly higher levels of AAT and M65 but lower ALB in severe compared to moderate COVID-19 patients. N-glycan analysis of the serum proteome revealed increased levels of oligomannose- and sialylated di-antennary glycans and decreased non-sialylated di-antennary glycan A2G2 in COVID-19 patients compared to controls.ConclusionsCOVID-19-associated changes in levels and N-glycosylation of specific plasma proteins highlight complexity of inflammatory process and grant further investigations.

The role of thrombin in haemostasis.

Thrombin is a multifunctional serine protease generated in injured cells. The generation of thrombin in coagulation plays a central role in the functioning of haemostasis. The last enzyme in the coagulation cascade is thrombin, with the function of cleaving fibrinogen to fibrin, which forms the fibrin clot of a haemostatic plug. Although thrombin primarily converts fibrinogen to fibrin, it also has many other positive regulatory effects on coagulation. Thrombin has procoagulant, inflammatory, cellular proliferation and anticoagulant effects. In coagulation system, thrombin has two very distinct roles. Firstly, it acts as a procoagulant when it converts fibrinogen into an insoluble fibrin clot, activates factor (F) XIII, activates thrombin activatable fibrinolysis inhibitor (TAFI) and activates FV, FVIII and FXI. Thrombin also enhances platelet adhesion by inactivating a disintegrin and metalloprotease with thrombospondin type1 motif (ADAMTS13). However, when thrombin activates protein C, it acts as an anticoagulant. A natural anticoagulant pathway that supplies regulation of the blood coagulation system contains protein C, which is the key component. This is accomplished by the specific proteolytic inactivation of FV and FVIII. In this review, the multiple roles of thrombin in the haemostatic response to injury are studied in addition to the cofactors that determine thrombin activity and how thrombin activity is thought to be coordinated.

Comparison of VWF-ADAMTS13 axis involvement in atrial fibrillation and sinus rhythm in patients with ST-elevation myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: None. Background Previous studies have shown that von Willebrand factor (VWF) increases, and a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) decreases in myocardial infarction. Few studies have examined the involvement of the VWF-ADAMTS13 axis in ST-elevation myocardial infarction (STEMI) patients with atrial fibrillation (AF). Purpose Our aim was to investigate VWF-ADAMTS13 axis involvement in atrial fibrillation in STEMI. Methods The subjects of this study were participants in an observational study for investigating the difference in the pathology of thrombus retrieved from infarct-related artery between AF and sinus rhythm (SR). From June 2019 to August 2020, patients who underwent thrombus aspiration for STEMI at our hospital. Only subjects whose thrombus could be confirmed were enrolled. They were divided into two groups, the AF group, and the SR group. Serum biomarkers, including ADAMTS13 activity, and VWF were evaluated. Results 34 patients with STEMI who were able to aspirate thrombus were enrolled in the study. They were divided into two groups: 6 patients with AF (AF group, mean age 72.5 years, 100% male) and 28 patients with SR (SR group, mean age 63.0 years, 100% male). ADAMTS13 activity was significantly lower in AF group than SR group (AF: 0.63 ± 0.14 vs. SR: 0.77 ± 0.13 U / mL, p = 0.037). There was no significant difference in VWF antigen between the two groups (AF: 251 ± 56 vs. SR: 204 ± 69%, p = 0.170). VWF/ADAMTS13 activity in AF group were significantly higher than in SR group. Conclusion Our study suggests an association between the VWF-ADAMTS13 axis and atrial fibrillation in STEMI. Abstract Table. Comparison of serum biomarkers

Ratio of von Willebrand factor antigen to ADAMTS13 activity is a useful biomarker for acute-on-chronic liver failure development and prognosis in patients with liver cirrhosis.

Acute-on-chronic liver failure (ACLF) is associated with a high risk of short-term mortality after progression to multiple organ failure. A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) is a metalloproteinase that specifically cleaves multimeric von Willebrand factor (VWF). An imbalance between ADAMTS13 enzyme and VWF substrate is associated with liver cirrhosis progression that induces ACLF. This study examined the relationship between ADAMTS13 and VWF and ACLF development to determine whether ADAMTS13 and VWF are useful predictive biomarkers for ACLF development and prognosis of patients with liver cirrhosis. The study enrolled 67 patients with Child-Pugh class A and B liver cirrhosis. ADAMTS13 activity (ADAMTS13:AC) and VWF antigen (VWF:Ag) were measured using enzyme-linked immunosorbent assays. The ratio of VWF:Ag to ADAMTS13:AC (VWF:Ag/ADAMTS13:AC) was used to divide patients into two groups according to the classification and regression tree based on Gray model survival analysis. Compared with patients with Child-Pugh class A liver cirrhosis, class B patients had a higher VWF:Ag/ADAMTS13:AC and a higher risk of ACLF development. Cumulative incidence of ACLF was significantly higher in patients with high (>7.9) versus low (≤7.9) VWF:Ag/ADAMTS13:AC (hazard ratio [HR], 6.50; 95% CI, 2.31-18.29; p<0.001). Cumulative survival was significantly lower in cirrhotic patients with high versus low VWF:Ag/ADAMTS13:AC (HR 5.11; 95% CI, 1.85-14.14; p=0.002). For patients with liver cirrhosis, VWF:Ag/ADAMTS13:AC is associated with functional liver reserve and predicts the development of ACLF and the prognosis.

Abstract 10207: Association Between Age and the Von Willebrand Factor-ADAMTS13 Axis in Patients with ST-Elevation Myocardial Infarction

Introduction: The incidence of arterial thrombosis increases with age, but its underlying mechanisms are unclear. Myocardial infarction is associated with increased von Willebrand factor (VWF) and decreased a disintegrin-like and metalloproteinase with thrombospondin type-1 motif 13 (ADAMTS13) levels. We aimed to examine the relationship between the VWF-ADAMTS13 axis and age in ST-elevation myocardial infarction (STEMI). Methods: Patients who underwent endovascular arterial recanalization for STEMI or acute ischemic stroke (AIS) and had aspirated thrombi at our institute between June 2019 and August 2020 were enrolled. Seventy-one patients were divided into two age groups—&lt;65 years (n = 23) and ≥65 years (n = 48). The ADAMTS13 and VWF antigen levels were evaluated. Results: Among all patients (STEMI and AIS), ADAMTS13 levels were significantly lower in the ≥65 years group than in the &lt;65 years group (0.77 ± 0.16 vs. 0.67 ± 0.16 U/mL, p = 0.024). The VWF antigen/ADAMTS13 levels were significantly higher in the ≥65 years group (319 ± 223 vs. 359 ± 160, P = 0.032). Among patients with STEMI, compared to the &lt;65 years group, the ≥65 years group had significantly lower ADAMTS13 levels and a significantly higher VWF antigen-ADAMTS13 ratio. Among patients with AIS, there were no significant differences in ADAMTS13 and WVF antigen levels and VWF antigen-ADAMTS13 ratio between the &lt;65 and the ≥65 years groups. Conclusions: Our study demonstrated low ADAMTS13 levels in elderly patients with STEMI, but not in those with AIS. The VWF-ADAMTS13 axis may be more involved in the pathogenesis of STEMI than in that of AIS among elderly patients.

Optimization of anti-ADAMTS13 antibodies for the treatment of ADAMTS13-related bleeding disorder in patients receiving circulatory assist device support

ADAMTS13 (a disintegrin-like and metalloproteinase with thrombospondin type-1 motif 13)-related bleeding disorder has been frequently observed as a life-threatening clinical complication in patients carrying a circulatory assist device. Currently, treatment modalities for the bleeding disorder are very limited and not always successful. To address the unmet medical need, we constructed humanized antibodies of mouse anti-ADAMTS13 antibody A10 (mA10) by using complementarity-determining region (CDR) grafting techniques with human antibody frameworks, 8A7 and 16E8. The characteristics of the two humanized A10 antibodies, namely A10/8A7 and A10/16E8, were assessed in vitro and in silico. Among the two humanized A10 antibodies, the binding affinity of A10/16E8 to ADAMTS13 was comparable to that of mA10 and human-mouse chimeric A10. In addition, A10/16E8 largely inhibited the ADAMTS13 activity in vitro. The results indicated that A10/16E8 retained the binding affinity and inhibitory activity of mA10. To compare the antibody structures, we performed antibody structure modeling and structural similarity analysis in silico. As a result, A10/16E8 showed higher structural similarity to mA10, compared with A10/8A7, suggesting that A10/16E8 retains a native structure of mA10 as well as its antigen binding affinity and activity. A10/16E8 has great potential as a therapeutic agent for ADAMTS13-related bleeding disorder.

P18 Steroid-induced malignant hypertension causing cytopenia in a case of lupus nephritis

Case report - IntroductionProteinuria, hypertension and renal impairment are among the features of lupus nephritis, whereas seizure and cytopenia are part of systemic manifestations of active lupus. In these situations, high-dose steroid is usually considered and can lead to severe/malignant hypertension (MHT). We are reporting a case of lupus nephritis admitted with seizures and later developed thrombotic microangiopathy (TMA). Further evaluation revealed a diagnosis of steroid-induced malignant hypertension which was later improved after controlling blood pressure and reducing the dose of steroid. Case report - Case descriptionA 25-year-old lady who was previously diagnosed at 17 years old with systemic lupus erythematosus (SLE) based on clinical features of polyarthralgia, lymphadenopathy, fatigability and positive auto immune profile. She was lost to follow up since the diagnosis and had not been on relevant treatment. She was recently admitted with myalgia, polyarthralgia, pleural effusion and leg oedema. Blood test showed stage 2, acute kidney injury and urine analysis showed significant proteinuria (PCR 826mg/mmol). Renal biopsy showed class IV lupus nephritis and she was commenced on prednisolone 50 mg orally and was discharged home with outpatient follow up appointment.A few days later, she presented with generalized tonic clonic seizure. Physical examination revealed high blood pressure at 160/120 mmHg. MRI brain scan did not show features of ischaemia or thrombosis. She was treated with antiepileptic, antihypertensive medications and parenteral methylprednisolone 500 mg in view of lupus with neurological manifestation. While being on methylprednisolone, her blood pressure further rose with systolic 220/ diastolic 170 mmHg. Her blood parameter started deteriorating showing features of microangiopathic haemolytic anaemia (MAHA) with low haemoglobin of 56 and low platelets of 46. Blood test for anti-cardiolipin antibody, lupus anticoagulant were negative and marker for thrombotic thrombocytopenic purpura (TTP) Serum ADAMTS13 (A Disintegrin and Metalloprotease with a Thrombospondin type1 motif, member 13) was normal. Haematology team’s opinion was sought and TTP ruled out as a cause of her anaemia and thrombocytopenia. Repeat blood test did not show any features of worsening lupus and urine analysis showed improved proteinuria. Management plan was focused on controlling her blood pressure with optimization of antihypertensive medications. Parenteral steroid therapy was stopped. Within a few days of achieving good control of blood pressure, cytopenia improved. Antiepileptic treatment was stopped and she did not have any further episodes of seizure. Case report - DiscussionIn assessing a case of lupus nephritis who appeared to have MAHA and thrombocytopenia with severe HTN, clinicians need to consider possibility of TMA along with other common differentials such as active lupus, TTP and haemolytic uraemic syndrome (HUS). In this case lupus nephritis and neurological manifestation (seizure) diverted attention towards active lupus. Patient was treated with parenteral steroids in order to control active lupus which caused worsening haematological parameters. Steroid-induced malignant hypertension can be difficult to consider as a differential diagnosis in these situations and can be easily missed.TMA is a rare but serious condition which describes a specific pathological abnormality in the vessel wall of arterioles and capillaries leading to microvascular thrombosis. It is commonly manifested as MAHA and thrombocytopenia in blood film which indicates underlying endothelial injury. This case’s blood film showed thrombocytopenia and red blood cell fragmentation suggestive of MAHA. Malignant hypertension is one of the underlying causes of TMA where blood pressure control would be the most critical and may be the only management required to reverse the haematological abnormality as was evident in this case. Case report - Key learning pointsCytopenia in a case of SLE can be due to autoimmune process or drug-induced. However, malignant hypertension can also cause thrombotic microangiopathy which can lead to cytopenia. Thus, clinicians should be vigilant and relate this complication to the high dose of steroid.

Detection of two insertion/deletions (indels) within the ADAMTS9 gene and their associations with growth traits in goat

Abstract The “A Disintegrin and Metalloproteinase with Thrombospondin Type-1 motifs 9″ (ADAMTS9) is a Zn2+-dependent metalloproteinases of ADAMTSs family, and it regulates growth and development of mammals. Here, the aim of this study was to explore the genetic variations of ADAMTS9 gene and evaluate their effect on growth performance. Herein, two novel deletions (22-bp and 14-bp) were found and their significant associations were detected in Shaanbei white cashmere (SBWC) goats (n = 1006). Further analysis showed low linkage disequilibrium. The results indicated that the 22-bp deletion was related to chest width (CW; P = 0.002), chest width index (CWI; P = 1.18E-04) and chest circumference index (CCI; P = 0.022), and the individuals with II genotype had lower CW, CWI and CCI. Another 14-bp deletion was associated with height across the hip (P = 0.039) and the II genotype was the dominant genotype. Combination analysis revealed that there were five joint genotypes with relatively high combination frequency, and significant effects were found for them on chest width (CW; P ≤ 0.020), chest circumference (CC; P ≤ 0.015), chest circumference index (CCI; P ≤ 0.047) and chest width index (CWI; P ≤ 0.006). Individuals with joint genotypes IP2DP2IP3DP3 and IP2DP2IP3IP3 had higher values. Together, these findings hinted that the two novel indels within ADAMTS9 gene were related to growth traits in goat, which may provide functional genetic markers for improving economical traits in goat breeding.

Association between the ADAMTS proteinases and obstructive sleep apnea.

A disintegrin and metalloproteinase with thrombospondin type-1 motifs (ADAMTS) proteinases have important roles in degradation/repairing of extracellular matrix (ECM). They are thought to play a key role in pathogenesis of many diseases. We aimed to investigate the association between ADAMTS 2, 3, and 14 (procollagen) and obstructive sleep apnea (OSA). Eighty-six individuals who were suspected of OSA were included. All cases underwent polysomnography. Participants were divided into 3 groups according to apnea-hypopnea index (AHI): control (n = 22), mild-to-moderate OSA (n = 36), and severe OSA (n = 28). ADAMTS proteinases 2, 3, and 14 were analyzed in serum samples. When compared with other groups, patients with severe OSA showed significantly higher body mass index (BMI) (p = 0.001), whereas they showed significantly lower ADAMTS 3 levels (p = 0.016). No difference was found between groups with respect to the levels ADAMTS 2 and 14. There was a negative relation between the levels of ADAMTS 3 and the severity of OSA (Kendall's tau = - 0.19, p = 0.021). The levels of ADAMTS 3 were also found to be positively correlated with minimum SpO2 (r = 0.31, p = 0.004) and negatively correlated with BMI, AHI, oxygen desaturation index (ODI), time duration with oxygen saturation < 90% (T90), and CRP (r = - 0.31 to - 0.49, p < 0.05). Multivariable regression analysis revealed that BMI (p = 0.013) and CRP levels (p = 0.005) were significantly associated with the levels of ADAMTS 3. ADAMTS 3, one of the procollagen proteinases, was decreased in severe OSA. Lack of ADAMTS 3 proteinase may contribute to process of sleep apnea due to insufficient collagen syntheses.

Turbulent Flow Promotes Cleavage of VWF (von Willebrand Factor) by ADAMTS13 (A Disintegrin and Metalloproteinase With a Thrombospondin Type-1 Motif, Member 13).

Objective- Acquired von Willebrand syndrome is defined by excessive cleavage of the VWF (von Willebrand Factor) and is associated with impaired primary hemostasis and severe bleeding. It often develops when blood is exposed to nonphysiological flow such as in aortic stenosis or mechanical circulatory support. We evaluated the role of laminar, transitional, and turbulent flow on VWF cleavage and the effects on VWF function. Approach and Results- We used a vane rheometer to generate laminar, transitional, and turbulent flow and evaluate the effect of each on VWF cleavage in the presence of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type-1 motif, member 13). We performed functional assays to evaluate the effect of these flows on VWF structure and function. Computational fluid dynamics was used to estimate the flow fields and forces within the vane rheometer under each flow condition. Turbulent flow is required for excessive cleavage of VWF in an ADAMTS13-dependent manner. The assay was repeated with whole blood, and the turbulent flow had the same effect. Our computational fluid dynamics results show that under turbulent conditions, the Kolmogorov scale approaches the size of VWF. Finally, cleavage of VWF in this study has functional consequences under flow as the resulting VWF has decreased ability to bind platelets and collagen. Conclusions- Turbulent flow mediates VWF cleavage in the presence of ADAMTS13, decreasing the ability of VWF to sustain platelet adhesion. These findings impact the design of mechanical circulatory support devices and are relevant to pathological environments where turbulence is added to circulation.

ADAMTS13 and von Willebrand factor are useful biomarkers for sorafenib treatment efficiency in patients with hepatocellular carcinoma.

BACKGROUNDMany advanced hepatocellular carcinoma (HCC) patients are receiving sorafenib treatment. Sorafenib reportedly improves overall survival (OS) significantly in patients with HCC. Prediction of sorafenib response and prognosis in patients with HCC receiving sorafenib treatment are important due to the potentially serious side effects of sorafenib. A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) and von Willebrand factor (VWF) are associated with the pathophysiology of liver cirrhosis and HCC through their roles in hypercoagulability; they are also associated with angiogenesis via vascular endothelial growth factor (VEGF). The imbalance between ADAMTS13 and VWF was associated with prognosis of various cancers in patients undergoing chemotherapy.AIMTo investigate ADAMTS13 and VWF as potential biomarkers for sorafenib response and prognosis in patients with HCC receiving sorafenib treatment.METHODSForty-one patients with HCC receiving sorafenib treatment were included in this study. The initial daily sorafenib dose was 400 mg in all patients. ADAMTS13 activity (ADAMTS13:AC), VWF antigen (VWF:Ag), VEGF levels were determined by enzyme-linked immunosorbent assay. Univariate and multivariate analyses were used to determine predictive factors for sorafenib response and prognosis in patients with HCC receiving sorafenib treatment.RESULTSADAMTS13:AC was significantly higher in patients with stable disease (SD), partial response (PR), and complete response (CR) than in those with progressive disease (PD) (P < 0.05). In contrast, VWF:Ag and the VWF:Ag/ADAMTS13:AC ratio were significantly lower in patients with SD, PR, and CR than in those with PD (P < 0.05 for both). Multivariate analysis showed that the VWF:Ag/ADAMTS13:AC ratio was the only predictive factor for sorafenib response and ADAMTS13:AC was the only prognostic factor in patients with HCC receiving sorafenib treatment. The patients with a low ADAMTS13:AC (< 78.0) had significantly higher VEGF levels than those with a high ADAMTS13:AC (≥ 78.0) (P < 0.05).CONCLUSIONThe VWF:Ag/ADAMTS13:AC ratio and ADAMTS13:AC are potentially useful biomarkers for sorafenib response and prognosis, respectively, in patients with HCC receiving sorafenib treatment.

Adamts9 is necessary for ovarian development in zebrafish

Expression of adamts9 (A disintegrin and metalloprotease with thrombospondin type-1 motif, member 9) increases dramatically in the somatic cells surrounding oocytes during ovulation in vertebrates from zebrafish to human. However, the function of Adamts9 during ovulation has not been determined due to the embryonic lethality of knockouts in mice and Drosophila. To identify the role of Adamts9 during ovulation we generated knockout (adamts9−/−) zebrafish using CRISPR/Cas9 and characterized the effects of the mutation. From 1047 fish generated by crossing adamts9+/− pairs, we found significantly fewer adult adamts9−/− fish (4%) than predicted by Mendelian ratios (25%). Of the mutants found, there was a significant male bias (82%). Only 3 female mutants were identified (7%), and they had small ovaries with few stage III and IV oocytes compared to wildtype (wt) counterparts of comparable size and age. Astoundingly, the remaining mutants (11%) did not appear to have normal testis or ovaries. Instead there was a pair of transparent, ovarian-like membranous shells that filled the abdominal cavity. Histological examination confirmed that shells were largely empty with no internal structure. Surprisingly, seminiferous tubules and various spermatocytes including mature spermatozoa were observed on the periphery of these transparent shells. No female or female like knockouts were observed to release eggs, and no ovulated oocytes were observed in histological sections. To our knowledge, this is the first report of an adamts9 global knockout model in any adult vertebrates and the first description of how gonadal sex and structure are affected- highlighting the importance of Adamts9 during gonadal development and the value of zebrafish as a model organism.

Elevated ADAMTS13 Activity is Associated with Poor Postoperative Outcome in Patients Undergoing Liver Resection

Recently, von-Willebrand-Factor (vWF) has been shown to correlate with postoperative liver dysfunction (LD). Accordingly, “disintegrin-like metalloprotease with thrombospondin type1 motif” (ADAMTS13) is known to cleave vWF in less active fragments. Thus, we aimed to evaluate the diagnostic potential of ADAMTS13-activity (ADAMTS13-AC) to identify patients with postoperative LD after hepatectomy. Accordingly 37 patients undergoing hepatectomy for different neoplastic entities were included in this study. Plasma ADAMTS13-AC and vWF-Ag were measured 1 day prior to (preOP), 1 and 5 days (POD1/5) after hepatectomy. In accordance to the ISGLS-criteria LD was prospectively recorded. In this context, perioperative ADAMTS13-AC- and vWF-Ag/ADAMTS13-AC-ratio- levels revealed a significant increase after hepatectomy. Accordingly, elevated vWF-Ag/ADAMTS13-AC-ratio significantly predicted LD (preOP AUC: 0.75, p = 0.02; POD1 AUC: 0.80, p = 0.03). Patients who fulfilled our perioperative vWF-Ag/ADAMTS13-AC-ratio cut-off-levels (preOP: ≥116, POD1: ≥165) suffered from significantly higher incidences of LD (preOP: 70% vs. 30%, p = 0.01; POD1: 83% vs. 17%, p = 0.001). In conclusion, perioperative ADAMTS13-AC measurement may serve as a useful parameter to early detect high-risk patients developing postoperative LD prior to liver resection in patients suffering from hepatic malignancies. Indeed, further investigations have to be performed to consolidate its role as a predictive marker for LD.

Major Changes of von Willebrand Factor Multimer Distribution in Cirrhotic Patients with Stable Disease or Acute Decompensation.

Background There is an unstable balance between pro- and anti-haemostatic processes in patients with cirrhosis. We hypothesized, that in patients with acute decompensation (AD) the major alterations of von Willebrand factor (VWF) could contribute to the pro-thrombotic situation as compared to patients with stable (ST) cirrhosis. Patients and Methods We analysed different parameters of VWF, including detailed multimer distribution by densitometry and platelet adhesion, together with a d isintegrin-like a nd m etalloproteinase with t hrombo s pondin type-1 motifs 13 (ADAMTS13) activity and antigen and C-reactive protein (CRP) levels in patients with ST cirrhosis ( n = 99), with AD ( n = 54) and controls ( n = 92). Results VWF antigen, ristocetin co-factor as well as collagen-binding activities were elevated in both cirrhotic groups in a stepwise manner. There was a decrease in high and an increase in low molecular weight multimer ratios in the majority of ST cirrhosis. However, in 24 out of 54 AD patients, ultra-large VWF multimers (ultra-large molecular weight multimers [ULMWM]) were found. ADAMTS13 activity in ST and AD patients without ULMWM was similar to controls (median [interquartile range; IQR]%: 98 [67–132] and 91 [60–110] vs. 106 [88–117], respectively). The presence of ULMWM in AD patients was associated with low ADAMTS13 activity [33 (24–49)%] and high CRP level [23 (7.1–83.6) mg/L]. Adhesion of normal platelets showed a stepwise increase in the presence of cirrhotic plasmas, reaching the highest level in AD patients with ULMWM. Conclusion Characteristic changes of VWF parameters are seen in ST cirrhosis. In AD patients, highly increased VWF and reduced ADAMTS13 activity could be found, along with the presence of ULMWM, which are possible markers and contributors of the disease progression.

Insights into 3D Structure of ADAMTS13: A Stepping Stone towards Novel Therapeutic Treatment of Thrombotic Thrombocytopenic Purpura.

ADAMTS13 (A D: isintegrin A: nd M: etalloprotease with a T: hromboS: pondin type-1 motif, member 13: ) and von Willebrand factor (VWF) can be considered as scale weights which control platelet adhesion during primary haemostasis. In a very uncommon condition designated thrombotic thrombocytopenic purpura (TTP), functional absence of ADAMTS13 tips the balance toward VWF-mediated platelet adhesion in the microcirculation. TTP is associated with a high mortality and arises from either a congenital or acquired autoimmune deficiency of the plasma enzyme ADAMTS13. In case of acquired ADAMTS13 deficiency, autoantibodies bind to and inhibit the function of ADAMTS13. Currently available treatments of TTP aim to supply ADAMTS13 through plasma exchange or are aimed at B-cell depletion with rituximab. None of the available therapeutics, however, aims at protection of ADAMTS13 from circulating autoantibodies. In this review, our aim is to describe the structure-function relationship of ADAMTS13 employing homology models and previously published crystal structures. Structural bioinformatics investigation of ADAMTS13 reveals many insights and explains how mutations and autoantibodies may lead to the pathophysiology of TTP. The results of these studies provide a roadmap for the further development of rationally designed therapeutics for the treatment of patients with acquired TTP. In addition, we share our opinion on the state of the art of the open-closed conformations of ADAMTS13 which regulate the activity of this highly specific VWF cleaving protease.