| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Juto, A, et al.
(author)
-
MYELOPEROXIDASE (MPO) POSITIVE EXTRACELLULAR VESICLES (EVS) EXPRESSING COMPLEMENT SPLIT PRODUCTS IN ANTI-NEUTROPHIL CYTOPLASMIC ANTIBODY (ANCA)-ASSOCIATED VASCULITIS (AAV)
- 2022
-
In: ANNALS OF THE RHEUMATIC DISEASES. - : BMJ. - 0003-4967 .- 1468-2060. ; 81, s. 1434-1434
-
Conference paper (other academic/artistic)abstract
- Complement activation has a critical role for the development of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We have previously shown increased expression of complement split products C3a and C5a on myeloperoxidase (MPO) positive EVs (MPO+EVs) in plasma from AAV patients with kidney involvement compared to the patients with non-renal disease and the EV-levels correlated with disease activity (1).ObjectivesTo investigate the expression of a larger set of complement components on circulating MPO+EVs in relation to disease activity and kidney involvement in patients with AAV.MethodsEighty-nine patients with AAV and 23 healthy controls were included. The concentration of MPO+EVs expressing complement split products C3a, C4d, C5a, terminal complement complex-TCC (C5b-9) or complement factor B (CFB) were analyzed from citrate plasma by flow cytometry. The assessment of vasculitis disease activity was performed using the Birmingham Vasculitis Activity Score (BVAS).ResultsIn the AAV group, there were 47 males (52.8%), the median age was 56 years and 33 (37.1%) patients were anti-MPO-positive and 54 (60.7%) were anti-PR3-positive. Two patients were positive for both antibodies. Median disease duration for patients with active AAV (BVAS>0; n=81) was 4 days and for patients in remission (BVAS 0; n=8) 1259 days. 64% had kidney involvement (n=52). Highly active AAV (BVAS ≥12) was noted in 62 patients, of whom 49 patients had kidney involvement. Active disease (0<BVAS<12) was seen in 19 patients. AAV patients had significantly higher levels of MPO+, MPO+C3a+, MPO+C4d+ and MPO+TCC+ EVs compared to healthy controls (all p<0.001). Patients in remission had higher levels of MPO+, MPO+C4d+ and MPO+TCC+ EVs compared to healthy controls (all p≤0.001). There was a significant difference in levels of MPO+(p=0.02), MPO+C3a+(p<0.001), MPO+C4d+(p<0.001) and MPO+TCC+ EVs (p<0.001) in patients with kidney involvement compared with patients without (n=29) (Figure 1). For patients with BVAS>0 there was a weak correlation between MPO+, MPO+C3a+, MPO+C4d+, MPO+TCC+ EVs and BVAS. Kidney biopsies from 34 patients were classified according to histopathological class (2): crescentic (n=6), focal (n=18), mixed (n=6), sclerotic (n=4). The level of MPO+C4d+EVs was higher in the sclerotic type compared to focal (p=0.04, 95% CI [2.4–103.7]) and mixed (p=0.04, 95% CI [1.4–119.1]).ConclusionLevels of EVs expressing complement split products were generally increased in AAV patients and patients with kidney involvement had higher levels of total MPO+EVs exposing C3a, C4d or TCC compared with patients without suggesting a role in kidney AAV pathogenesis. Patients with sclerotic kidney histotype had higher levels of MPO+C4d EVs compared with focal and mixed subgroups pointing to that activation of the classical complement pathway may be of importance in severe forms of kidney AAV.References[1]Antovic A et al. J Rheumatol. 2020 May 1;47(5):714-721. doi: 10.3899/jrheum.181347. Epub 2019 Aug 1. PMID: 31371653.[2]Berden AE et al. J Am Soc Nephrol. 2010 Oct;21(10):1628-36. doi: 10.1681/ASN.2010050477. Epub 2010 Jul 8. PMID: 20616173.Disclosure of InterestsNone declared
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
- Pruner, I, et al.
(author)
-
The Silence Speaks, but We Do Not Listen: Synonymous c.1824C>T Gene Variant in the Last Exon of the Prothrombin Gene as a New Prothrombotic Risk Factor
- 2020
-
In: Clinical chemistry. - : Oxford University Press (OUP). - 1530-8561 .- 0009-9147. ; 66:2, s. 379-389
-
Journal article (peer-reviewed)abstract
- BackgroundThrombosis is a major global disease burden with almost 60% of cases related to underlying heredity and most cases still idiopathic. Synonymous single nucleotide polymorphisms (sSNPs) are considered silent and phenotypically neutral. Our previous study revealed a novel synonymous FII c.1824C>T variant as a potential risk factor for pregnancy loss, but it has not yet been associated with thrombotic diseases.MethodsTo determine the frequency of the FII c.1824C>T variant we have sequenced patients’ DNA. Prothrombin RNA expression was measured by quantitative PCR. Functional analyses included routine hemostasis tests, western blotting and ELISA to determine prothrombin levels in plasma, and global hemostasis assays for thrombin and fibrin generation in carriers of the FII c.1824C>T variant. Scanning electron microscopy was used to examine the structure of fibrin clots.ResultsFrequency of the FII c.1824C>T variant was significantly increased in patients with venous thromboembolism and cerebrovascular insult. Examination in vitro demonstrated increased expression of prothrombin mRNA in FII c.1824T transfected cells. Our ex vivo study of FII c.1824C>T carriers showed that the presence of this variant was associated with hyperprothrombinemia, hypofibrinolysis, and formation of densely packed fibrin clots resistant to fibrinolysis.ConclusionOur data indicate that FII c.1824C>T, although a synonymous variant, leads to the development of a prothrombotic phenotype and could represent a new prothrombotic risk factor. As a silent variant, FII c.1824C>T would probably be overlooked during genetic screening, and our results show that it could not be detected in routine laboratory tests.
|
|
| 12. |
- Zong, Y, et al.
(author)
-
Synergistic Effect of Bypassing Agents and Sequence Identical Analogue of Emicizumab and Fibrin Clot Structure in the In Vitro Model of Hemophilia A
- 2020
-
In: TH open : companion journal to thrombosis and haemostasis. - : Georg Thieme Verlag KG. - 2512-9465. ; 4:2, s. e94-e103
-
Journal article (peer-reviewed)abstract
- Development of inhibitors to factor VIII (FVIII) occurs in approximately 30% of severe hemophilia A (HA) patients. These patients are treated with bypassing agents (activated prothrombin complex concentrate [aPCC] and recombinant activated FVII-rFVIIa). Recently, a bispecific FIX/FIXa- and FX/FXa-directed antibody (emicizumab) has been approved for the treatment of HA patients with inhibitors. However, the data from clinical studies imply that coadministration of emicizumab and bypassing agents, especially aPCC, could have a thrombotic effect.This study was aimed to address the question of potential hypercoagulability of emicizumab and bypassing agents' coadministration, we have investigated fibrin clot formation and structure in the in vitro model of severe HA after adding sequence-identical analogue (SIA) of emicizumab and bypassing agents.Combined overall hemostasis potential (OHP) and fibrin clot turbidity assay was performed in FVIII-deficient plasma after addition of different concentrations of SIA, rFVIIa, and aPCC. Pooled normal plasma was used as control. The fibrin clots were analyzed by scanning electron microscopy (SEM).OHP and turbidity parameters improved with the addition of aPCC, while therapeutic concentrations of rFVIIa did not show substantial improvement. SIA alone and in combination with rFVIIa or low aPCC concentration improved OHP and turbidity parameters and stabilized fibrin network, while in combination with higher concentrations of aPCC expressed hypercoagulable pattern and generated denser clots.Our in vitro model suggests that combination of SIA and aPCC could potentially be prothrombotic, due to hypercoagulable changes in fibrin clot turbidity and morphology. Additionally, combination of SIA and rFVIIa leads to the formation of stable clots similar to normal fibrin clots.
|
|
