Reduced ADAMTS13 activity is associated with an ADAMTS13 SNP, fever and microparticles in a malaria-like model

The Role of the von Willebrand Factor Collagen-Binding Assay (VWF:CB) in the Diagnosis and Treatment of von Willebrand Disease (VWD) and Way Beyond: A Comprehensive 36-Year History

The von Willebrand factor (VWF) collagen binding (VWF:CB) assay was first reported for use in von Willebrand diagnostics in 1986, by Brown and Bosak. Since then, the VWF:CB has continued to be used to help diagnose von Willebrand disease (VWD) (correctly) and also to help assign the correct subtype, as well as to assist in the monitoring of VWD therapy, especially desmopressin (DDAVP). However, it is important to recognize that the specific value of any VWF:CB is predicated on the use of an optimized VWF:CB, and that not all VWF:CB assays are so optimized. There are some good commercial assays available, but there are also some "not-so-good" commercial assays available, and these may continue to give the VWF:CB "a bad reputation." In addition to VWD diagnosis and management, the VWF:CB found purpose in a variety of other applications, from assessing ADAMTS13 activity, to investigation into acquired von Willebrand syndrome (especially as associated with use of mechanical circulatory support or cardiac assist devices), to assessment of VWF activity in disease states in where an excess of high-molecular-weight VWF may accumulate, and lead to increased (micro)thrombosis risk (e.g., coronavirus disease 2019, thrombotic thrombocytopenic purpura). The VWF:CB turns 37 in 2023. This review is a celebration of the utility of the VWF:CB over this nearly 40-year history.

Genetic Variation in ADAMTS13 is Related to VWF Levels, Atrial Fibrillation and Cerebral Ischemic Events

INTRODUCTION

ADAMTS13 cleaves von Willebrand factor (VWF) multimers into less active fragments. Both markers have been related to cardiovascular disease (CVD). We aimed to investigate the influence of ADAMTS13 single nucleotide polymorphisms (SNPs) on levels of ADAMTS13 and VWF, and CVD.

METHODS

The c.1342C>G, g.41635A>G and c.2699C>T polymorphisms were determined in patients with chronic coronary syndrome (n = 1000). VWF and ADAMTS13 were analyzed. Clinical endpoints after 2 years (n = 106) were unstable angina pectoris, myocardial infarction, non-hemorrhagic stroke and death.

RESULTS

The SNPs did not affect ADAMTS13 levels. The 41635A-allele associated with higher VWF levels (P < .001). Patients with the 1342G-allele had significantly higher frequency of previous atrial fibrillation (n = 26, P = .016) and cerebral ischemic events (n = 47, P = .030). Heterozygous of the 1342CG variant experienced more clinical endpoints compared to homozygous (CC and GG) (P = .028).

CONCLUSION

The association between the 41635A-allele and VWF indicates a role for this polymorphism in VWF regulation. ADAMTS13 has previously been linked to atrial fibrillation and ischemic stroke, and our findings suggest that the 1342G-allele may be of significance. The association between the 1342CG genotype and endpoints needs further investigations.Clinicaltrials.gov, ASCET, NCT00222261. https://clinicaltrials.gov/ct2/show/NCT00222261?term=NCT00222261&draw=2&rank=1.

Temperature-dependent irreversible conformational change of recombinant ADAMTS13 upon metal ion chelation

BACKGROUND

The catalytic domain of ADAMTS13 possesses one Zn2+ and up to three putative Ca2+ binding sites and can be inactivated by chelating agents. Although replenishment with an appropriate metallic cation is thought to restore the enzyme's proteolytic activity fully, ADAMTS13 stability in a metal ion-depleting environment has not been explored.

OBJECTIVES

To address the stability of ADAMTS13 in citrated human plasma.

METHODS

ADAMTS13 activity was measured using the FRETS-VWF73 fluorogenic assay. The molar ratio of metals bound to ADAMTS13 was determined by size exclusion chromatography inductively coupled plasma mass spectrometry (SEC-ICP-MS). Higher-order structural changes were analyzed using Fourier-transformed infrared spectroscopy and dynamic light scattering.

RESULTS

ADAMTS13 was stable at room temperature for up to 24 hours irrespective of the presence of citrate (0.38%). However, at 37°C, citrate caused a time-dependent activity decrease. No ADAMTS13 activity decrease was seen in heparinized plasma, but the addition of citrate again caused ADAMTS13 instability at 37°C. Scavenging of citrate by the addition of Ca2+ or Zn2+ prior to but not postincubation prevented the activity decrease of the enzyme. The SEC-ICP-MS analyses showed that ADAMTS13 only bound Zn2+ and that its reduced activity correlated with a gradual loss of bound Zn2+ . Concomitant higher-order structural analyses demonstrated structural changes in ADAMTS13 that are typical of less-ordered protein structures.

CONCLUSIONS

Zn2+ is required to stabilize ADAMTS13 structure at physiologic temperature, thereby preventing irreversible loss of enzyme activity. This finding is particularly important to consider when using citrated human plasma as a source of ADAMTS13 in clinical settings.

Association of a disintegrin and metalloproteinase with a thrombospondin type 1 motif member 13 polymorphisms with severity of coronary stenosis in type 2 diabetes mellitus

Background:

The imbalance of von Willebrand factor (vWF) and a disintegrin and metalloproteinase with a thrombospondin type 1 motif member 13 (ADAMTS13) has been associated with atherosclerosis progression. A high level of vWF which regulates thrombus formation is associated with diabetes mellitus (DM), and some ADAMTS13 and vWF polymorphisms have effects on their levels. Therefore, this study aimed to evaluate the associations of ADAMTS13 and vWF polymorphisms and their levels with DM and severity of coronary stenosis.

Materials and Methods:

Eighty-seven DM and 84 control individuals were recruited. vWF and ADAMTS13 activities as well as vWF antigen were measured by collagen-binding assay (CBA), residual-CBA, and in-house enzyme-linked immunosorbent assay, respectively. ADAMTS13 and vWF polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism.

Results:

The E and G alleles and AA genotype of ADAMTS13 Q448E, rs2073932, and rs652600, respectively, were independently associated with DM (odds ratio [OR] [95% confidence interval (CI)] = 2.5 [1.1, 5.6], 2.3 [1.0, 5.2], and 4.7 [1.2, 18.6], respectively). Moreover, E allele and AA genotype of Q448E and rs652600 were also significantly associated with multi-vessel disease (OR [95% CI] = 2.2 [1.0, 4.8] and 3.2 [1.0, 10.0], respectively), while the E and G allele of Q448E and rs2073932 were associated with high Gensini score (OR [95% CI] = 2.3 [1.1, 4.9] and 2.3 [1.1, 5.1], respectively).

Conclusion:

Association of ADAMTS13 polymorphisms with DM, number of vessel stenosis, and Gensini score may indicate the possible contribution of ADAMTS13 polymorphisms to atherosclerosis progression and severity of coronary stenosis in DM.

Effects of Polymorphisms in the SjSP-13 Gene of Schistosoma japonicum on Its Diagnostic Efficacy and Immunogenicity

Schistosomiasis japonica is one of the most prevalent parasitic diseases in China. The scarcity of effective diagnostic tools is a major factor that contributes to the high prevalence of schistosomiasis japonica. SjSP-13 is a promising serological diagnostic biomarker of the disease. However, it is unclear whether polymorphisms in SjSP-13 affect its diagnostic efficacy and immunogenicity. Here, we found the SjSP-13 gene was highly polymorphic, and all the alleles of the gene were clustered into two clades, clade A and B. SjSP-13.6 and SjSP-13.25, the representative alleles of clade A and B, were produced in Escherichia coli. The diagnostic value of SjSP-13.6 (AUC = 0.983 ± 0.006), was found to be similar to the SjSP-13.25 (AUC = 0.973 ± 0.009) by receiver operating characteristic (ROC) analysis. SjSP-13.6 and SjSP-13.25 have the same specificity (96.7%), while the sensitivity of SjSP-13.6 (90.4%) is slightly but not significantly higher than SjSP-13.25 (85.2%). The combination use of the two alleles (SjSP-13.6/25) didn’t increase the diagnostic performance of SjSP-13 as the AUC value of SjSP-13.6/25 is 0.977 ± 0.009, lower than individual SjSP-13.6 (AUC = 0.983 ± 0.006). In addition, we found the immunogenicity of clade A alleles is significantly higher than clade B in Schistosoma japonicum naturally infected animals and patients, as the mean antibody levels of SjSP-13.6 was significantly higher than SjSP-13.25. We conclude that polymorphisms of the SjSP-13 gene should not affect its diagnostic efficacy, and it is not necessary to combine the alleles of the two clades for diagnosis of schistosomiasis.

Protective effect of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 haplotype on coronary artery disease

: Genetic variations of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) and von Willebrand factor (vWF) were related to ADAMTS13 levels. Reduction of ADAMTS13 activity may affect atherosclerotic progression. However, the associations of polymorphisms of these genes with coronary artery disease (CAD) are still unclear. This study, therefore, aimed to investigate the relationship of genetic variations and haplotypes of ADAMTS13 and vWF with CAD risk in Thais. A case-control study was performed in 197 CAD and 135 non-CAD patients. Genetic polymorphisms of ADAMTS13 (P475S, Q448E, rs2073932, P618A, A900V, S903L, rs652600, and rs4962153) and vWF (V1565L and Y1584C) along with ADAMTS13 activity, vWF antigen and vWF activity were examined in the patients. The vWF V1565L polymorphism was associated with increased ADAMTS13 activity, whereas none of ADAMTS13 polymorphisms or haplotypes was associated with its activity. Interestingly, haplotype analysis indicated that the QAGA or H4 haplotype of ADAMTS13 gene had a protective effect on CAD after adjustment for ABO blood group [odds ratio (OR) = 0.3, 95% confidence interval (CI) = 0.1, 0.6] and major CAD risk factors (OR = 0.3, 95% CI = 0.1, 0.7). However, the combination of H4 haplotype and the L allele of V1565L was not associated with increased ADAMTS13 activity when compared with the V allele. ADAMTS13 haplotype had an independent protective effect on CAD and genetic variation of vWF V1565L polymorphism modulates ADAMTS13 activity.