ARTICLE | doi:10.20944/preprints202305.1556.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: Heparin; heparin; hemocompatibility; activated carbon; adsorption
Online: 23 May 2023 (04:07:59 CEST)
Activated carbon (AC) is an effective adsorbent for creatinine removal in hemoperfusion. However, the hemocompatibility and adsorption capacity of AC was required to be improved furthermore. Heparin, a widely used anticoagulant biomacromolecule, could improve the hemocompatibility of the absorbents in different ways based on its molecular weight. Thus, it was necessary to study the surface modification with unfractionated heparin (UFH) or low molecular weight heparin (LMWH) on improvement of hemocompatibility and adsorption. In this study, UFH and LMWH were respectively grafted on AC through polyethyleneimine as an intermediate layer. The modification of AC about morphology, mechanical strength and pore structure was characterized by XPS, SEM, TA and BET. It was found that compared with AC, the morphology and mechanical strength AC-UFH and AC-LMWH could be well maintained, but the BET surface was decreased due to the grafting of macromolecules. Furthermore, AC-UFH and AC-LMWH showed the better hemocompatibility on protein adsorption, APTT and platelet activation compared with AC, in which AC-LMWH had lower fibrinogen adsorption and longer APTT than AC-UFH. Besides, it was found that AC, AC-UFH and AC-LMWH had no significant effect on blood cell composition. Finally, the adsorption capacity of adsorbents for creatinine was evaluated. Although there was no significant difference between AC-UFH and AC-LMWH, it was found that heparin could be interacted with creatinine to enhance the adsorption capacity when compared with AC-PEI. This study deepened the understanding of anticoagulation of heparinized surface and provided a theoretical basis for adsorbents in hemoperfusion.
ARTICLE | doi:10.20944/preprints202005.0020.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: COVID-19; , 2019-nCoV; Heparin; Ivermectin; Spike Shielding
Online: 2 May 2020 (16:21:32 CEST)
The disease of COVID-19 comprises the most serious against human health worldwide with a high rate of virulence and mortality. The disease is caused by the 2019-nCoV virus from the beta coronavirus family. The virus makes use of its surface glycoprotein named S protein or spike to enter the human cells. The virus attached to its receptor named angiotensin-converting enzyme 2 on host cells surface via its receptor-binding domain and its fusion is mediated by cleavage at S2' site that is carried out by surface protease. Vaccines or drugs interfering with S protein binding or cleavage sites could be considered as drugs to get rid of the infection. In the current work and though docking and molecular dynamic experiments we have checked more than 100 drugs with high enough molecular weights for their shielding potency toward S protein binding sites and processing S2' sites. Our results indicate the shielding potency of: fidaxomicin > ivermectin > heparin > azithromycin > clarithromycin > eryhthromycin > niclosamide > ritonavir. Considering affluent reports regarding the complex disturbance in the immune system and multi-organ involvement in the disease there is no single or binary drug regime for cure expectedly and instead, we claim the multi-drug regime should be the choice in this context. Accordingly, we suggest our extracted drugs as an adjuvant for clinical trials.
ARTICLE | doi:10.20944/preprints202006.0249.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: SARS-CoV-2; TMPRSS2; antibody epitopes; glycosylation sequons; heparin
Online: 21 June 2020 (10:12:34 CEST)
The 2019 novel SARS-like coronavirus (SARS-CoV-2) entry depends on the host membrane serine protease TMPRSS2, which can be blocked by some clinically-proven drugs. Here we analyzed spatial relevance between glycosylation sequons and antibody epitopes and found that, different from SARS-CoV S, most high-surface-accessible epitopes of SARS-CoV-2 S are blocked by the glycosylation, and the optimal epitope with the highest surface accessibility is covered by the S1 cap. TMPRSS2 inhibitor treatments may prevent unmasking of this epitope and therefore prolong virus clearance and may induce antibody-dependent enhancement. Interestingly, a heparin-binding sequence immediately upstream of the S1/S2 cleavage site has been found in SARS-CoV-2 S but not in SARS-CoV S. Binding of SARS-CoV-2 with heparins may lead to exposure of S686, which then facilitates the S1/S2 cleavage, induces exposure of the optimal epitope, and therefore increases the antibody titres. A combination of heparin and vaccine (or convalescent serum) treatments thus is recommended.
BRIEF REPORT | doi:10.20944/preprints202104.0312.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Tinzaparin; African swine fever; heparin shortage; fraxiparin; neurosurgery; perioperative anticoagulation
Online: 12 April 2021 (14:06:07 CEST)
Background An outbreak of African swine fever (ASF) in China in 2020 has led to an unprecedented shortage of fraxiparin. Most patients, especially those kept in hospital for surgery, are currently treated with prophylactic anticoagulation (AC). In search of alternatives for fraxiparin, we found no sufficient data on alternatives for neurosurgical patients, such as tinzaparin of European origin. We compared fraxiparin and tinzaparin concerning adverse events (bleeding versus thromboembolic events) in neurosurgical patients. Methods Between 2012 and 2018, 517 neurosurgical patients with benign and malignant brain tumors as well as 297 patients with subarachnoid hemorrhage (SAH) were treated in the Department of Neurosurgery, University Hospital Leipzig receiving prophylactic anticoagulation within 48 hours. In 2015, prophylactic anticoagulation was switched from fraxiparin to tinzaparin throughout the university hospital. In a retrospective manner, the frequency and occurrence of adverse events (rebleeding and thromboembolic events) in connection with the substance used was analyzed. Statistical analysis was performed using Fisher’s exact test and the chi-squared test. Results Rebleeding rates were similar in both fraxiparin and tinzaparin cohorts in patients being treated for meningioma, glioma, and SAH combined (8.8 vs 10.3%). Accordingly, the rates of overall thromboembolic events were not significantly different (5.5% vs 4.3%). The severity of rebleeding did not vary. There was no significant difference among subgroups when compared for deep vein thrombosis (DVT) or pulmonary embolism (PE). Conclusion In this retrospective study, tinzaparin seems to be a safe alternative to fraxiparin for AC in patients undergoing brain tumor surgery or suffering from SAH.
ARTICLE | doi:10.20944/preprints202305.1749.v1
Subject: Biology And Life Sciences, Virology Keywords: Marine sulfated glycans; SARS-CoV-2; Omicron XBB.1.5; Spike protein; Heparin
Online: 25 May 2023 (07:12:52 CEST)
Keywords: Marine sulfated glycans; SARS-CoV-2; Omicron XBB.1.5, Spike protein; Heparin
ARTICLE | doi:10.20944/preprints202007.0627.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: Erythrocytapheresis; red blood cell exchange; sickle cell disease; target HbS level; heparin locking
Online: 26 July 2020 (02:22:35 CEST)
The aim of our study was to describe our experience using a Spectra Optia® automated apheresis system in children with sickle cell disease (SCD). We used automated red blood cell exchange (RCE) to treat acute and chronic complications in 75 children with SCD who had a median age of 10 years [7-13]. We analysed 649 exchange sessions. Peripheral venous access was limited in a number of the children, thus requiring a femoral central double‐lumen venous catheter (CVC). We recommend the use of heparin locking, with 500 units in each lumen of a CVC. This method was well tolerated, with few complications during the procedures. For preoperative prevention, all of the patients had achieved a post-RCE HbS level of <30% since this is a mandatory condition imposed by the anaesthesiologist. With a post-RCE Hb level of approximately 10-11 g/dL, a blood exchange volume of ≥32 mL/kg, and an interval between each RCE procedure of ≤30 days, it was able to maintain the residual HbS level below 30%. Despite a target pre‐exchange HbS level of 47%, we did not encounter a single stroke recurrence. Erythrocytapheresis is useful and safe for children with SCD.
REVIEW | doi:10.20944/preprints202007.0516.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Megakaryocyte, IFITM3, VWF, ADAMTS13, emperipolesis, self-association, unfractionated heparin (UFH), histone, NETs, Thrombin
Online: 22 July 2020 (11:03:08 CEST)
COVID-19 thromboembolic disease has brought all of us back to the drawing board. In COVID-19, pre-existing activated endothelium with increased Von Willebrand factor (VWF), low density lipoprotein (LDL) promoting “self-association” and “sticking” of long VWF strings to the vascular endothelial wall, suppressed ADAMTS13 cleavage of VWF, hypoxia induced upregulation and activation of VWF, fibrous network from neutrophil extracellular traps (NETs) with free DNA and histone, all appear to be initiating the thrombogenesis. Worsening complement activation, cytokine storm and resulting endothelial destruction, unregulated thrombogenesis leads to vascular occlusions and hypoxia. At this stage, the presence of abundant extracellular DNA, histone and -defensins appears worse than the SARS-CoV-2 itself. Previously observed in vitro mechanisms like histone “auto-activating” prothrombin, histone activated platelets generating thrombin without FXII, thrombin and plasmin cleaving complement C5 appears highly likely in COVID-19. Megakaryocytes are actively producing platelets in the lungs and appear to play a major role in thrombogenesis of COVID-19 raising suspicion of emperipolesis. This focused review is a compilation of my observations in relation to the pathophysiology of the intravascular environment, mainly in COVID-19 lungs. Pathophysiology based clinical trials are paramount in reducing morbidity and mortality in COVID-19.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: COVID-19; vaccine; heparin; thrombocytopenia; thrombosis; platelet; endothelial cell; autoimmunity; proteoglycan; B cell; coagulation
Online: 9 April 2021 (10:13:14 CEST)
Prothrombotic thrombocytopathy mimicking heparin-induced thrombocytopenia has been observed in patients with severe COVID-19 and after immunisation with the Vaxzevria vaccine. Herein, we discuss the possible pathogenesis of this disorder focusing on the possible involvement of anti-platelet factor 4 (PFA) autoantibodies.