Heparin as a therapy for COVID-19: current evidence and future possibilities

Promising Drug Fondaparinux for the Treatment of COVID-19: an In Silico Analysis of Low Molecular Weight Heparin, Direct Oral Anticoagulant, and Antiplatelet Drug Interactions with Host Protease Furin

PURPOSE

As of July 2022, the COVID-19 pandemic has affected over 555 million worldwide confirmed cases and caused more than 6.3 million deaths. The studies showed that the D-dimer levels were increased in non-survivors compared to survivors and heparin treatment has begun to be administered to the patients in severe clinics. As we knew that the entrance of SARS-CoV-2 to the host cell needs to be facilitated by host proteases; we published our hypothesis that heparin as a serine protease inhibitor may block the interaction between spike protein receptor-binding domain and host proteases. In our study, we aimed to investigate the interactions between not only heparins but also other antiplatelet and anticoagulant drugs including fondaparinux.

METHODS

In this study, docking studies were carried out to evaluate the interactions between low molecular weight heparins (LMWHs) (enoxaparin, dalteparin, tinzaparin), direct oral anticoagulant, and antiplatelet drugs with host proteases. Molecular docking studies were performed by using Schrödinger molecular modeling software. 3D structures of the ligands were obtained from the 2D structures by assigning the OPLS-2005 force field using the Maestro 12.7. The 3D crystal structure of the furin complexed with an inhibitor, 2,5-dideoksistreptamin derivative, was extracted from the Protein Data Bank (PDB ID: 5MIM). Docking studies were carried out using the Grid-based Ligand Docking with Energetics module of the Schrödinger Software.

RESULTS

The docking studies revealed that fondaparinux was the most relevant molecule to interact with furin with a docking score of - 12.74. It showed better interaction than the natural ligand of furin with an increased score compared to the docking score of - 8.155 of the natural ligand. AnaGA*IsA structure representing LMWH structure has shown a docking score of - 11.562 which was also better than the score of the natural ligand of furin.

CONCLUSION

Our findings have shown that LMWHs and fondaparinux can be used for their possible antiviral effects in COVID-19 patients. Our results have shown that in accordance with heparin and LMWH, fondaparinux can also be a candidate for "drug repurposing" in COVID-19 therapy, not only because of their anticoagulant but also possible antiviral effects.

A systematic review of thromboembolic complications and outcomes in hospitalised COVID-19 patients

Thromboembolic (TE) complications [myocardial infarction (MI), stroke, deep vein thrombosis (DVT), and pulmonary embolism (PE)] are common causes of mortality in hospitalised COVID-19 patients. Therefore, this review was undertaken to explore the incidence of TE complications and mortality associated with TE complications in hospitalised COVID-19 patients from different studies. A literature search was performed using ScienceDirect and PubMed databases using the MeSH term search strategy of "COVID-19", "thromboembolic complication", "venous thromboembolism", "arterial thromboembolism", "deep vein thrombosis", "pulmonary embolism", "myocardial infarction", "stroke", and "mortality". There were 33 studies included in this review. Studies have revealed that COVID-19 patients tend to develop venous thromboembolism (PE:1.0-40.0% and DVT:0.4-84%) compared to arterial thromboembolism (stroke:0.5-15.2% and MI:0.8-8.7%). Lastly, the all-cause mortality of COVID-19 patients ranged from 4.8 to 63%, whereas the incidence of mortality associated with TE complications was between 5% and 48%. A wide range of incidences of TE complications and mortality associated with TE complications can be seen among hospitalized COVID-19 patients. Therefore, every patient should be assessed for the risk of thromboembolic complications and provided with an appropriate thromboprophylaxis management plan tailored to their individual needs.

Sulfated liposome-based artificial cell membrane glycocalyx nanodecoys for coronavirus inactivation by membrane fusion

As a broad-spectrum antiviral nanoparticle, the cell membrane nanodecoy is a promising strategy for preventing viral infections. However, most of the cell membrane nanodecoys can only catch virus and cannot induce inactivation, which may bring about a considerably high risk of re-infection owing to the possible viral escape from the nanodecoys. To tackle this challenge, sulfated liposomes are employed to mimic the cell membrane glycocalyx for constructing an artificial cell membrane glycocalyx nanodecoy that exhibits excellent anti-coronavirus activity against HCoV-OC43, wild-type SARS-CoV-2, Alpha and Delta variant SARS-CoV-2 pseudovirus. In addition, this nanodecoy, loaded with surface sulfate groups as SARS-CoV-2 receptor arrays, can enhance the antiviral capability to virus inactivation through destroying the virus membrane structure and transfer the spike protein to postfusion conformation. Integrating bio-inspired recognition and inactivation of viruses in a single supramolecular entity, the artificial cell membrane nanodecoy opens a new avenue for the development of theranostic antiviral nanosystems, whose mass production is favored due to the facile engineering of sulfated liposomes.

The Inhibition of Serine Proteases by Serpins Is Augmented by Negatively Charged Heparin: A Concise Review of Some Clinically Relevant Interactions

Serine proteases are members of a large family of hydrolytic enzymes in which a particular serine residue in the active site performs an essential role as a nucleophile, which is required for their proteolytic cleavage function. The array of functions performed by serine proteases is vast and includes, among others, the following: (i) the ability to fight infections; (ii) the activation of blood coagulation or blood clot lysis systems; (iii) the activation of digestive enzymes; and (iv) reproduction. Serine protease activity is highly regulated by multiple families of protease inhibitors, known collectively as the SERine Protease INhibitor (SERPIN). The serpins use a conformational change mechanism to inhibit proteases in an irreversible way. The unusual conformational change required for serpin function provides an elegant opportunity for allosteric regulation by the binding of cofactors, of which the most well-studied is heparin. The goal of this review is to discuss some of the clinically relevant serine protease-serpin interactions that may be enhanced by heparin or other negatively charged polysaccharides. The paired serine protease-serpin in the framework of heparin that we review includes the following: thrombin-antithrombin III, plasmin-anti-plasmin, C1 esterase/kallikrein-C1 esterase inhibitor, and furin/TMPRSS2 (serine protease Transmembrane Protease 2)-alpha-1-antitrypsin, with the latter in the context of COVID-19 and prostate cancer.

Control of tissue homeostasis by the extracellular matrix: Synthetic heparan sulfate as a promising therapeutic for periodontal health and bone regeneration

Proteoglycans are core proteins associated with carbohydrate/sugar moieties that are highly variable in disaccharide composition, which dictates their function. These carbohydrates are named glycosaminoglycans, and they can be attached to proteoglycans or found free in tissues or on cell surfaces. Glycosaminoglycans such as hyaluronan, chondroitin sulfate, dermatan sulfate, keratan sulfate, and heparin/heparan sulfate have multiple functions including involvement in inflammation, immunity and connective tissue structure, and integrity. Heparan sulfate is a highly sulfated polysaccharide that is abundant in the periodontium including alveolar bone. Recent evidence supports the contention that heparan sulfate is an important player in modulating interactions between damage associated molecular patterns and inflammatory receptors expressed by various cell types. The structure of heparan sulfate is reported to dictate its function, thus, the utilization of a homogenous and structurally defined heparan sulfate polysaccharide for modulation of cell function offers therapeutic potential. Recently, a chemoenzymatic approach was developed to allow production of many structurally defined heparan sulfate carbohydrates. These oligosaccharides have been studied in various pathological inflammatory conditions to better understand their function and their potential application in promoting tissue homeostasis. We have observed that specific size and sulfation patterns can modulate inflammation and promote tissue maintenance including an anabolic effect in alveolar bone. Thus, new evidence provides a strong impetus to explore heparan sulfate as a potential novel therapeutic agent to treat periodontitis, support alveolar bone maintenance, and promote bone formation.

Development and Validation of RP-HPLC Method for the Determination of Enoxaparin Sodium in Dry Injection Formulation

Enoxaparin sodium is an anticoagulant medication that is used as a blood thinning agent. It is mostly used for the treatment and prevention of deep vein thrombosis (DVT) and pulmonary embolism (PE). It is also used in certain surgeries and during pregnancy. For the treatment of acute coronary syndrome (ACS) and heart attacks, it may be used. Enoxaparin sodium was validated by the RP-HPLC method. A simple RP-HPLC method was developed in a single HPLC run in a dry powder injection formulation. All injections of HPLC sample were 20 μL volume. The chromatographic separation was completed in the isocratic mode. The used column was USP-L8 (250 mm × 4.6 mm) of BDS type of 10 μm meters in the same mobile phase throughout the analysis by using methanol and ultrapure water with a ratio of 7:93, respectively. The flow rate was 1.0 mL/min. The mobile phase was filtered through 0.45 μm filter paper, and isocratic elution was performed. The refractive index (RI) detector was used to analyze this sample. The specific peak of enoxaparin sodium was observed at 5:56 min. The calculated detection limit (LOD) was 0.351 ppm, and the calculated quantitation limit was 1.063 ppm. In repeatability of precision, the average calculated assay (%) was 100.85%, and the calculated RSD (%) was 0.01. In the accuracy test, the RSD (%) was 0.50, and the mean recovery (%) was 100.35. The system's suitability was within the limit. This newly developed method is proposed according to ICH guidelines, and rules and can be applied effectively for the exact estimation of enoxaparin sodium in injection formulation. This newly developed methodology is affordable in cost as long as less time is taken and the consumption of samples is in smaller quantities for every investigation. In medicinal chemistry, the USP (United States Pharmacopeia) and BP (British Pharmacopeia) are directly involved in production as well as in quality testing.

From bench to bedside: potential of translational research in COVID-19 and beyond

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease 2019 (COVID-19) have been around for more than 3 years now. However, due to constant viral evolution, novel variants are emerging, leaving old treatment protocols redundant. As treatment options dwindle, infection rates continue to rise and seasonal infection surges become progressively common across the world, rapid solutions are required. With genomic and proteomic methods generating enormous amounts of data to expand our understanding of SARS-CoV-2 biology, there is an urgent requirement for the development of novel therapeutic methods that can allow translational research to flourish. In this review, we highlight the current state of COVID-19 in the world and the effects of post-infection sequelae. We present the contribution of translational research in COVID-19, with various current and novel therapeutic approaches, including antivirals, monoclonal antibodies and vaccines, as well as alternate treatment methods such as immunomodulators, currently being studied and reiterate the importance of translational research in the development of various strategies to contain COVID-19.

Low dose aspirin and clinical outcomes in patients with SARS-CoV-2 pneumonia: a propensity score-matched cohort analysis from the National SIMI‑COVID‑19 Registry

BACKGROUND

SARS- CoV-2 virus has had dramatic consequences worldwide being able to cause acute respiratory distress syndrome (ARDS), massive thrombosis and pulmonary embolism and, finally, patients' death. In COVID-19 infection, platelets have a procoagulant phenotype that can cause thrombosis in the pulmonary and systemic vascular network. Aspirin is a well-known anti-platelet drug widely used for the prevention of cardiovascular events and systematic reviews suggest a possible benefit of low-dose aspirin (LDA) use in the prevention and treatment of ARDS in patients with COVID-19 infection. However, several studies are available in the literature which do not support any benefits and no association with the patients' outcome. Therefore, currently available data are inconclusive.

MATERIALS AND PATIENTS

Data from the nationwide cohort multicenter study of the Italian Society of Internal Medicine (SIMI) were analyzed. We conducted a propensity score-matched cohort analysis to investigate the impact of chronic assumption of LDA on mortality of adult COVID-19 patients admitted in Internal Medicine Units (IMU). Data from 3044 COVID-19 patients who referred to 41 Italian hospitals between February 3rd to May 8th 2020 were analyzed. A propensity score-matched analysis was conducted using the following variables: age, sex, hypertension, hyperlipidemia diabetes, atrial fibrillation, cerebrovascular disease, COPD, CKD and stratified upon LDA usage, excluding anticoagulant treatment. After matching, 380 patients were included in the final analysis (190 in LDA group and 190 in no-LDA group).

RESULTS

66.2% were male, median age was 77 [70-83]. 34.8% of the population died during the hospitalization. Cardiovascular diseases were not significantly different between the groups. After comparison of LDA and no-LDA subgroups, we didn't record a significant difference in mortality rate (35.7% vs 33.7%) duration of hospital stay and ICU admission. In a logistic regression model, age (OR 1.05; 95% CI 1.01-1.09), FiO2 (OR 1.024; 95% CI 1.03-1.04) and days between symptoms onset and hospitalization (OR 0.93; 95% CI 0.87-0.99) were the only variables independently associated with death.

Digital-like Enzyme Inhibition Mechanism-Based Strategy for the Digital Sensing of Heparin-Specific Biomarkers

A new microbead (MB)-based digital flow cytometric sensing system is proposed for the sensitive detection of heparin-specific biomarkers, including heparin-binding protein (HBP) and heparinase. This strategy takes advantage of the inherent space-confined enzymatic behavior of T4 polynucleotide kinase phosphatase (T4 PNKP) around a single MB and the heparin's digital-like inhibitory effect on T4 PNKP. By integrating with an on-bead terminal deoxynucleotidyl transferase (TdT)-catalyzed fluorescence signal amplification technology, the concentration of HBP and heparinase can be digitally determined by the number of fluorescence-positive/-negative MBs which can be easily counted by flow cytometry. This is not only the first test to expand the application scenario of T4 PNKP to the digital detection of different biomarkers but also pioneers a new direction for fabricating digital biosensing platforms based on the enzyme inhibition mechanism.

Early treatment with low-molecular-weight heparin reduces mortality rate in SARS-CoV-2 patients

BACKGROUND

Since the beginning of the SARS-CoV-2 pandemic, millions of people have been infected and died. Different therapeutic approaches have been recommended, but only a few have shown clinical advantages. Low-molecular-weight heparin (LMWH) has been recommended to prevent COVID-19-related thrombo-embolic events. We aimed to evaluate the impact of early treatment with LMWH on hospital admission and death in patients with SARS-CoV-2 infection.

METHODS

We conducted an observational monocentric retrospective study to evaluate the preventive role of LMWH on the mortality rate of COVID-19 patients. SARS-CoV-2 infected patients were recruited from the beginning of the Italian epidemic to March 31, 2021. We excluded patients with missing data and those chronically exposed to LMWH. Treatment prescription was based on international and national guidelines and modified depending on clinical presentation and drug-drug interactions.

RESULTS

Seven hundred thirty-four SARS-CoV-2 infected patients were recruited, with 357 (48.6%) males and a median (IQR) age of 77.9 (65-85.7) years. 77.5% of people developed SARS-CoV-2-related symptoms and 62.8% were admitted to the hospital, and 20.2% died. Four hundred ninety-two (67%) started LMWH. In particular, 296 (40.3%) were treated within five days since symptoms onset. At logistic regression, early LMWH therapy was associated with lower mortality. Furthermore, remdesivir treatment showed a lower risk of death. On the contrary, age, BMI>30 kg/m2, neurological diseases, fever or dyspnea were associated with an increased risk of death.

CONCLUSIONS

Early treatment with LMWH was associated with lower mortality in our cohort. Further studies are needed to better assess the role of wider LMWH administration in terms of timing and regimen dose.

Prophylactic anticoagulants for non-hospitalised people with COVID-19

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has impacted healthcare systems worldwide. Multiple reports on thromboembolic complications related to COVID-19 have been published, and researchers have described that people with COVID-19 are at high risk for developing venous thromboembolism (VTE). Anticoagulants have been used as pharmacological interventions to prevent arterial and venous thrombosis, and their use in the outpatient setting could potentially reduce the prevalence of vascular thrombosis and associated mortality in people with COVID-19. However, even lower doses used for a prophylactic purpose may result in adverse events such as bleeding. It is important to consider the evidence for anticoagulant use in non-hospitalised people with COVID-19.

OBJECTIVES

To evaluate the benefits and harms of prophylactic anticoagulants versus active comparators, placebo or no intervention, or non-pharmacological interventions in non-hospitalised people with COVID-19.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 18 April 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing prophylactic anticoagulants with placebo or no treatment, another active comparator, or non-pharmacological interventions in non-hospitalised people with COVID-19. We included studies that compared anticoagulants with a different dose of the same anticoagulant. We excluded studies with a duration of under two weeks.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. Our primary outcomes were all-cause mortality, VTE (deep vein thrombosis (DVT) or pulmonary embolism (PE)), and major bleeding. Our secondary outcomes were DVT, PE, need for hospitalisation, minor bleeding, adverse events, and quality of life. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included five RCTs with up to 90 days of follow-up (short term). Data were available for meta-analysis from 1777 participants. Anticoagulant compared to placebo or no treatment Five studies compared anticoagulants with placebo or no treatment and provided data for three of our outcomes of interest (all-cause mortality, major bleeding, and adverse events). The evidence suggests that prophylactic anticoagulants may lead to little or no difference in all-cause mortality (risk ratio (RR) 0.36, 95% confidence interval (CI) 0.04 to 3.61; 5 studies; 1777 participants; low-certainty evidence) and probably reduce VTE from 3% in the placebo group to 1% in the anticoagulant group (RR 0.36, 95% CI 0.16 to 0.85; 4 studies; 1259 participants; number needed to treat for an additional beneficial outcome (NNTB) = 50; moderate-certainty evidence). There may be little to no difference in major bleeding (RR 0.36, 95% CI 0.01 to 8.78; 5 studies; 1777 participants; low-certainty evidence). Anticoagulants probably result in little or no difference in DVT (RR 1.02, 95% CI 0.30 to 3.46; 3 studies; 1009 participants; moderate-certainty evidence), but probably reduce the risk of PE from 2.7% in the placebo group to 0.7% in the anticoagulant group (RR 0.25, 95% CI 0.08 to 0.79; 3 studies; 1009 participants; NNTB 50; moderate-certainty evidence). Anticoagulants probably lead to little or no difference in reducing hospitalisation (RR 1.01, 95% CI 0.59 to 1.75; 4 studies; 1459 participants; moderate-certainty evidence) and may lead to little or no difference in adverse events (minor bleeding, RR 2.46, 95% CI 0.90 to 6.72; 5 studies, 1777 participants; low-certainty evidence). Anticoagulant compared to a different dose of the same anticoagulant One study compared anticoagulant (higher-dose apixaban) with a different (standard) dose of the same anticoagulant and reported five relevant outcomes. No cases of all-cause mortality, VTE, or major bleeding occurred in either group during the 45-day follow-up (moderate-certainty evidence). Higher-dose apixaban compared to standard-dose apixaban may lead to little or no difference in reducing the need for hospitalisation (RR 1.89, 95% CI 0.17 to 20.58; 1 study; 278 participants; low-certainty evidence) or in the number of adverse events (minor bleeding, RR 0.47, 95% CI 0.09 to 2.54; 1 study; 278 participants; low-certainty evidence). Anticoagulant compared to antiplatelet agent One study compared anticoagulant (apixaban) with antiplatelet agent (aspirin) and reported five relevant outcomes. No cases of all-cause mortality or major bleeding occurred during the 45-day follow-up (moderate-certainty evidence). Apixaban may lead to little or no difference in VTE (RR 0.36, 95% CI 0.01 to 8.65; 1 study; 279 participants; low-certainty evidence), need for hospitalisation (RR 3.20, 95% CI 0.13 to 77.85; 1 study; 279 participants; low-certainty evidence), or adverse events (minor bleeding, RR 2.13, 95% CI 0.40 to 11.46; 1 study; 279 participants; low-certainty evidence). No included studies reported on quality of life or investigated anticoagulants compared to a different anticoagulant, or anticoagulants compared to non-pharmacological interventions.

AUTHORS' CONCLUSIONS

We found low- to moderate-certainty evidence from five RCTs that prophylactic anticoagulants result in little or no difference in major bleeding, DVT, need for hospitalisation, or adverse events when compared with placebo or no treatment in non-hospitalised people with COVID-19. Low-certainty evidence indicates that prophylactic anticoagulants may result in little or no difference in all-cause mortality when compared with placebo or no treatment, but moderate-certainty evidence indicates that prophylactic anticoagulants probably reduce the incidence of VTE and PE. Low-certainty evidence suggests that comparing different doses of the same prophylactic anticoagulant may result in little or no difference in need for hospitalisation or adverse events. Prophylactic anticoagulants may result in little or no difference in risk of VTE, hospitalisation, or adverse events when compared with antiplatelet agents (low-certainty evidence). Given that there were only short-term data from one study, these results should be interpreted with caution. Additional trials of sufficient duration are needed to clearly determine any effect on clinical outcomes.

Impact of thromboprophylaxis on hospital acquired thrombosis following discharge in patients admitted with COVID-19: Multicentre observational study in the UK

Post-discharge thromboprophylaxis in patients admitted with COVID-19 remains controversial. We aimed to determine the impact of thromboprophylaxis on hospital acquired thrombosis (HAT) in patients (≥18 years) discharged following admission for COVID-19 in an observational study across 26 NHS Trusts in the UK (01.04.2020-31.12.2021). Overall, 8895 patients were included to the study: 971 patients were discharged with thromboprophylaxis and propensity score matched (PSM) with a desired ratio of 1:1, from patients discharged without thromboprophylaxis. Patients with heparin induced thrombocytopenia, major bleeding during admission and pregnant women were excluded. As expected from 1:1 PSM, no difference was observed in parameters between the two groups, including duration of hospital stay, except the thromboprophylaxis group had a significantly higher proportion who had received therapeutic dose anticoagulation during admission. There were no differences in the laboratory parameters especially D-dimers between the two groups at admission or discharge. Median duration of thromboprophylaxis following discharge from hospital was 4 weeks (1-8 weeks). No difference was found in HAT in patients discharged with TP versus no TP (1.3% vs. 0.92%, p = 0.52). Increasing age and smoking significantly increased the risk of HAT. Many patients in both cohorts had raised D-dimer at discharge but D-dimer was not associated with increased risk of HAT.

Alpha-1-antitrypsin antagonizes COVID-19: a review of the epidemiology, molecular mechanisms, and clinical evidence

Alpha-1-antitrypsin (AAT), a serine protease inhibitor (serpin), is increasingly recognized to inhibit SARS-CoV-2 infection and counter many of the pathogenic mechanisms of COVID-19. Herein, we reviewed the epidemiologic evidence, the molecular mechanisms, and the clinical evidence that support this paradigm. As background to our discussion, we first examined the basic mechanism of SARS-CoV-2 infection and contend that despite the availability of vaccines and anti-viral agents, COVID-19 remains problematic due to viral evolution. We next underscored that measures to prevent severe COVID-19 currently exists but teeters on a balance and that current treatment for severe COVID-19 remains grossly suboptimal. We then reviewed the epidemiologic and clinical evidence that AAT deficiency increases risk of COVID-19 infection and of more severe disease, and the experimental evidence that AAT inhibits cell surface transmembrane protease 2 (TMPRSS2) - a host serine protease required for SARS-CoV-2 entry into cells - and that this inhibition may be augmented by heparin. We also elaborated on the panoply of other activities of AAT (and heparin) that could mitigate severity of COVID-19. Finally, we evaluated the available clinical evidence for AAT treatment of COVID-19.

Optimal dosing of heparin for prophylactic anticoagulation in critically ill COVID-19 patients a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The optimal amount of anticoagulation for critically ill COVID-19 patients is controversial. Therefore, we aimed to evaluate the efficacy and safety of escalated doses of anticoagulation in critically ill patients with severe COVID-19.

MATERIALS AND METHODS

We conducted a systematic search of three major databases, including PubMed, Cochrane Library, and Embase, from inception to May 2022. Randomized controlled trials (RCTs) were included comparing therapeutic or intermediate doses to standard prophylactic doses of anticoagulants in critically ill COVID-19 patients, with heparins as the only anticoagulation therapy considered.

RESULTS

Out of the six RCTs, 2130 patients were administered escalated dose anticoagulation (50.2%) and standard thromboprophylaxis therapy (49.8%). The escalated dose showed no significant impact on mortality (RR, 1.01; 95% CI, 0.90-1.13). Although there was no significant difference in DVT (RR, 0.81; 95% CI, 0.61-1.08), the risk of PE was significantly reduced in patients receiving escalated dose anticoagulation (RR, 0.35; 95% CI, 0.21-0.60), with an increased risk of bleeding events (RR, 1.65; 95% CI, 1.08-2.53).

CONCLUSION

This systematic review and meta-analysis fail to support escalated anticoagulation doses to reduce mortality in critically ill COVID-19 patients. However, higher doses of anticoagulants appear to reduce thrombotic events while increasing the risk of bleeding effectively.

Significance of heparin induced thrombocytopenia (HIT) in COVID-19: a systematic review and meta-analysis

Heparin-induced thrombocytopenia (HIT) occurs in approximately 3% of patients receiving heparinoids. About 30-75% of patients with type 2 of HIT develop thrombosis as a result of platelet activation. The most important clinical symptom is thrombocytopenia. Patients with severe COVID-19 are among those receiving heparinoids. This meta-analysis performed to picture the current knowledge and results of published studies in this field. Three search engines were searched and 575 papers were found. After evaluation, 37 articles were finally selected of which 13 studies were quantitatively analyzed. The pooled frequency rate of suspected cases with HIT in 13 studies with 11,241 patients was 1.7%. The frequency of HIT was 8.2% in the extracorporeal membrane oxygenation subgroup with 268 patients and 0.8% in the hospitalization subgroup with 10,887 patients. The coincidence of these two conditions may increase the risk of thrombosis. Of the 37 patients with COVID-19 and confirmed HIT, 30 patients (81%) were treated in the intensive care unit or had severe COVID-19. The most commonly used anticoagulants were UFH in 22 cases (59.4%). The median platelet count before treatment was 237 (176-290) x 10³/µl and the median nadir platelet count was 52 (31-90.5) x 10³/µl.

Well-Defined Heparin Mimetics Can Inhibit Binding of the Trimeric Spike of SARS-CoV-2 in a Length-Dependent Manner

The emergence of new SARS-CoV-2 variants and the dangers of long-covid necessitate the development of broad-acting therapeutics that can reduce viral burden. SARS-CoV-2 employs heparan sulfate (HS) as an initial cellular attachment factor, and therefore, there is interest in developing heparin as a therapeutic for SARS-CoV-2. Its use is, however, complicated by structural heterogeneity and the risk of causing bleeding and thrombocytopenia. Here, we describe the preparation of well-defined heparin mimetics by a controlled head-to-tail assembly of HS oligosaccharides having an alkyne or azide moiety by copper-catalyzed azide-alkyne cycloaddition (CuAAC). Alkyne- and azide-containing sulfated oligosaccharides were prepared from a common precursor by modifying an anomeric linker with 4-pentynoic acid and by enzymatic extension with an N-acetyl-glucosamine having an azide moiety at C-6 (GlcNAc6N₃), respectively, followed by CuAAC. The process of enzymatic extension with GlcNAc6N₃ followed by CuAAC with the desired alkyne-containing oligosaccharides could be repeated to give compounds composed of 20 and 27 monosaccharides, respectively. The heparin mimetics could inhibit the binding of the SARS-CoV-2 spike or RBD to immobilized heparin or to Vero E6 cells. The inhibitory potency increased with increasing chain length, and a compound composed of four sulfated hexasaccharides linked by triazoles had a similar potency as unfractionated heparin. Sequence analysis and HS microarray binding studies with a wide range of RBDs of variants of concern indicate that they have maintained HS-binding capabilities and selectivities. The heparin mimetics exhibit no or reduced binding to antithrombin-III and platelet factor 4, respectively, which are associated with side effects.

Low Molecular Weight Heparin, Anti-inflammatory/Immunoregulatory and Antiviral Effects, a Short Update

Low molecular weight heparin (LMWH) is a glycosaminoglycan long known for its anticoagulant properties. In recent times, recent evidence has associated this drug with extra pleiotropic anticoagulant effects that have also proven useful in the management of the treatment of COVID-19 infection indicating that heparin may play other roles in the management of the disease in addition to the prevention of thrombosis. Clinical observations and in vitro studies support that heparin has a potential multi-target effect. To date, the molecular mechanisms of these pleiotropic effects are not fully understood. This brief review presents some of the evidence from clinical and animal studies and describes the potential molecular mechanisms by which heparin may exert its anti-inflammatory/immunoregulatory and antiviral effects.

High-Dose Prophylactic Anticoagulation for COVID-19 Pneumonia: A Review of Benefits and Risks

The COVID-19 pandemic has had a devastating impact on a global scale, causing significant morbidity and mortality. The virus affects multiple organ systems, including the respiratory, cardiovascular, and coagulation systems, leading to severe pneumonia in some patients. Moreover, COVID-19 patients with severe pneumonia have a high incidence of thrombotic events, which can result in significant morbidity and mortality. Given the potential benefits of anticoagulation therapy in COVID-19 patients with thrombotic complications, recent studies have proposed high-dose prophylactic anticoagulation (HD-PA) therapy as a potential treatment option. In fact, some studies have suggested that HD-PA therapy may be more effective in reducing thrombotic events and mortality rates than other treatment options. This review aims to provide a comprehensive overview of the benefits and risks of HD-PA therapy for COVID-19 pneumonia patients. By synthesizing and analyzing the latest available research, we highlight patient selection criteria and discuss the optimal dosage, duration, and timing of therapy. Additionally, we review the potential risks associated with HD-PA therapy and provide recommendations for clinical practice. Ultimately, this review provides valuable insights into the use of HD-PA therapy in COVID-19 pneumonia patients and paves the way for further research in this critical area. By exploring the benefits and risks of this treatment option, we hope to provide healthcare professionals with the information they need to make informed decisions about the best course of treatment for their patients.

Clinical pathway of COVID-19 patients in primary health care in 30 European countries: Eurodata study

BACKGROUND

Most COVID-19 patients were treated in primary health care (PHC) in Europe.

OBJECTIVES

To demonstrate the scope of PHC workflow during the COVID-19 pandemic emphasising similarities and differences of patient's clinical pathways in Europe.

METHODS

Descriptive, cross-sectional study with data acquired through a semi-structured questionnaire in PHC in 30 European countries, created ad hoc and agreed upon among all researchers who participated in the study. GPs from each country answered the approved questionnaire. Main variable: PHC COVID-19 acute clinical pathway. All variables were collected from each country as of September 2020.

RESULTS

COVID-19 clinics in PHC facilities were organised in 8/30. Case detection and testing were performed in PHC in 27/30 countries. RT-PCR and lateral flow tests were performed in PHC in 23/30, free of charge with a medical prescription. Contact tracing was performed mainly by public health authorities. Mandatory isolation ranged from 5 to 14 days. Sick leave certification was given exclusively by GPs in 21/30 countries. Patient hotels or other resources to isolate patients were available in 12/30. Follow-up to monitor the symptoms and/or new complementary tests was made mainly by phone call (27/30). Chest X-ray and phlebotomy were performed in PHC in 18/30 and 23/30 countries, respectively. Oxygen and low-molecular-weight heparin were available in PHC (21/30).

CONCLUSION

In Europe PHC participated in many steps to diagnose, treat and monitor COVID-19 patients. Differences among countries might be addressed at European level for the management of future pandemics.

Cellular and molecular features of COVID-19 associated ARDS: therapeutic relevance

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection can be asymptomatic or cause a disease (COVID-19) characterized by different levels of severity. The main cause of severe COVID-19 and death is represented by acute (or acute on chronic) respiratory failure and acute respiratory distress syndrome (ARDS), often requiring hospital admission and ventilator support.The molecular pathogenesis of COVID-19-related ARDS (by now termed c-ARDS) is still poorly understood. In this review we will discuss the genetic susceptibility to COVID-19, the pathogenesis and the local and systemic biomarkers correlated with c-ARDS and the therapeutic options that target the cell signalling pathways of c-ARDS.

Heparin mimetics as potential intervention for COVID-19 and their bio-manufacturing

The COVID-19 pandemic has caused severe health problems worldwide and unprecedented decimation of the global economy. Moreover, after more than 2 years, many populations are still under pressure of infection. Thus, a broader perspective in developing antiviral strategies is still of great importance. Inspired by the observed multiple benefits of heparin in the treatment of thrombosis, the potential of low molecular weight heparin (LMWH) for the treatment of COVID-19 have been explored. Clinical applications found that LMWH decreased the level of inflammatory cytokines in COVID-19 patients, accordingly reducing lethality. Furthermore, several in vitro studies have demonstrated the important roles of heparan sulfate in SARS-CoV-2 infection and the inhibitory effects of heparin and heparin mimetics in viral infection. These clinical observations and designed studies argue for the potential to develop heparin mimetics as anti-SARS-CoV-2 drug candidates. In this review, we summarize the properties of heparin as an anticoagulant and the pharmaceutical possibilities for the treatment of virus infection, focusing on the perspectives of developing heparin mimetics via chemical synthesis, chemoenzymatic synthesis, and bioengineered production by microbial cell factories. The ultimate goal is to pave the eminent need for exploring novel compounds to treat coronavirus infection-caused diseases.

Case Report: Spontaneous Left Inferior Epigastric Artery Injury in a COVID-19 Female Patient Undergoing Anticoagulation Therapy

Since the beginning of the pandemic, a recommendation was made for the use of anticoagulants in high-risk hospitalized patients. This therapeutic approach has positive and negative effects regarding the outcome of the disease. Anticoagulant therapy prevents thromboembolic events, but it can also lead to spontaneous hematoma formation, or be accompanied by massive active bleeding. We present a 63-year-old COVID-19-positive female patient with a massive retroperitoneal hematoma and spontaneous left inferior epigastric artery injury.

[Advances in heparin structural analysis by chromatography technologies]

Heparin （Hp） is the most widely used anticoagulant drug in the clinics， with an annual global output of over 10 billion dollars. Hp， a member of the glycosaminoglycans （GAGs）， is prepared from porcine intestinal mucosa via extraction， separation， and purification. Hp is a linear polysaccharide with repeating disaccharide units. Low-molecular-weight heparins （LMWHs） are depolymerized from Hp via chemical or enzymatic degradation. Compared with Hp， LMWHs exhibit less bleeding side effect， milder immunogenicity， and higher bioavailability when injected subcutaneously. In general， Hps， including LMWHs， are high complex drugs with large molecular weights （MWs）， inhomogeneous MW distributions， and structural heterogeneity， including different degrees and locations of sulfonation， and unique residues generated from different production processes. Thus， developing efficient analytical methods to elucidate the structures of Hps and characterize or quantitate their properties is extremely challenging. Unfortunately， this problem limits their quality control， production optimization， clinical safety monitoring， and new applications. Research has constantly sought to elucidate the complicated structures of Hp drugs. Among the structural analysis and quality control methods of Hp currently available， chromatographic methods are the most widely studied and used. However， no literature thoroughly summarizes the specific applications of chromatographic methods in the structural analysis， manufacturing process， and quality control of Hp drugs. This paper systematically organizes and describes recent research progresses of the chromatographic methods used to analyze Hp drugs， including the identification and composition of monosaccharides， disaccharides， oligosaccharides， and polysaccharides. The applications， innovations， and limitations of these chromatographic methods are also summarized in this review. The insights obtained in this study will help production and quality control personnel， as well as drug researchers， obtain a deeper understanding of the complex structures of Hp drugs. This paper also provides a comprehensive reference for the structural analysis and quality control of Hps， proposes ideas for the development of new quality control methods， and lays a strong foundation for the in-depth structural elucidation of Hp drugs.

Alterations in platelet proteome signature and impaired platelet integrin αIIbβ3 activation in patients with COVID-19

BACKGROUND

Patients with COVID-19 are at increased risk of thrombosis, which is associated with altered platelet function and coagulopathy, contributing to excess mortality.

OBJECTIVES

To characterize the mechanism of altered platelet function in COVID-19 patients.

METHODS

The platelet proteome, platelet functional responses, and platelet-neutrophil aggregates were compared between patients hospitalized with COVID-19 and healthy control subjects using tandem mass tag proteomic analysis, Western blotting, and flow cytometry.

RESULTS

COVID-19 patients showed a different profile of platelet protein expression (858 altered of the 5773 quantified). Levels of COVID-19 plasma markers were enhanced in the platelets of COVID-19 patients. Gene ontology pathway analysis demonstrated that the levels of granule secretory proteins were raised, whereas those of platelet activation proteins, such as the thrombopoietin receptor and protein kinase Cα, were lowered. Basally, platelets of COVID-19 patients showed enhanced phosphatidylserine exposure, with unaltered integrin α_IIbβ₃ activation and P-selectin expression. Agonist-stimulated integrin α_IIbβ₃ activation and phosphatidylserine exposure, but not P-selectin expression, were decreased in COVID-19 patients. COVID-19 patients had high levels of platelet-neutrophil aggregates, even under basal conditions, compared to controls. This association was disrupted by blocking P-selectin, demonstrating that platelet P-selectin is critical for the interaction.

CONCLUSIONS

Overall, our data suggest the presence of 2 platelet populations in patients with COVID-19: one of circulating platelets with an altered proteome and reduced functional responses and another of P-selectin-expressing neutrophil-associated platelets. Platelet-driven thromboinflammation may therefore be one of the key factors enhancing the risk of thrombosis in COVID-19 patients.

Network pharmacology- and molecular simulation-based exploration of therapeutic targets and mechanisms of heparin for the treatment of sepsis/COVID-19

Critically infected patients with COVID-19 (coronavirus disease 2019) are prone to develop sepsis-related coagulopathy as a result of a robust immune response. The mechanism underlying the relationship between sepsis and COVID-19 is largely unknown. LMWH (low molecular weight heparin) exhibits both anti-inflammatory and anti-coagulating properties that result in a better prognosis of severely ill patients with COVID-19 co-associated with sepsis-induced coagulopathy or with a higher D-dimer value. Heparin-associated molecular targets and their mechanism of action in sepsis/COVID-19 are not well understood. In this work, we characterize the pharmacological targets, biological functions and therapeutic actions of heparin in sepsis/COVID-19 from the perspective of network pharmacology. A total of 38 potential targets for heparin action against sepsis/COVID-19 and 8 core pharmacological targets were identified, including IL6, KNG1, CXCL8, ALB, VEGFA, F2, IL10 and TNF. Moreover, enrichment analysis showed that heparin could help in treating sepsis/COVID-19 through immunomodulation, inhibition of the inflammatory response, regulation of angiogenesis and antiviral activity. The pharmacological effects of heparin against these targets were further confirmed by molecular docking and simulation analysis, suggesting that heparin exerts effective binding capacity by targeting the essential residues in sepsis/COVID-19. Prospective clinical practice evaluations may consider the use of these key prognostic indicators for the treatment of sepsis/COVID-19.Communicated by Ramaswamy H. Sarma.

Inhibition of platelet-surface-bound proteins during coagulation under flow II: Antithrombin and heparin

Blood coagulation is a self-repair process regulated by activated platelet surfaces, clotting factors, and inhibitors. Antithrombin (AT) is one such inhibitor that impedes coagulation by targeting and inactivating several key coagulation enzymes. The effect of AT is greatly enhanced in the presence of heparin, a common anticoagulant drug. When heparin binds to AT, it either bridges with the target enzyme or induces allosteric changes in AT leading to more favorable binding with the target enzyme. AT inhibition of fluid-phase enzymes caused little suppression of thrombin generation in our previous mathematical models of blood coagulation under flow. This is because in that model, flow itself was a greater inhibitor of the fluid-phase enzymes than AT. From clinical observations, it is clear that AT and heparin should have strong inhibitory effects on thrombin generation, and thus we hypothesized that AT could be inhibiting enzymes bound to activated platelet surfaces that are not subject to being washed away by flow. We extended our mathematical model to include the relevant reactions of AT inhibition at the activated platelet surfaces as well as those for unfractionated heparin and a low molecular weight heparin. Our results show that AT alone is only an effective inhibitor at low tissue factor densities, but in the presence of heparin, it can greatly alter, and in some cases shut down, thrombin generation. Additionally, we studied each target enzyme separately and found that inactivation of no single enzyme could substantially suppress thrombin generation.

Deep Survival Analysis With Clinical Variables for COVID-19

OBJECTIVE

Millions of people have been affected by coronavirus disease 2019 (COVID-19), which has caused millions of deaths around the world. Artificial intelligence (AI) plays an increasing role in all areas of patient care, including prognostics. This paper proposes a novel predictive model based on one dimensional convolutional neural networks (1D CNN) to use clinical variables in predicting the survival outcome of COVID-19 patients.

METHODS AND PROCEDURES

We have considered two scenarios for survival analysis, 1) uni-variate analysis using the Log-rank test and Kaplan-Meier estimator and 2) combining all clinical variables ([Formula: see text]=44) for predicting the short-term from long-term survival. We considered the random forest (RF) model as a baseline model, comparing to our proposed 1D CNN in predicting survival groups.

RESULTS

Our experiments using the univariate analysis show that nine clinical variables are significantly associated with the survival outcome with corrected p < 0.05. Our approach of 1D CNN shows a significant improvement in performance metrics compared to the RF and the state-of-the-art techniques (i.e., 1D CNN) in predicting the survival group of patients with COVID-19.

CONCLUSION

Our model has been tested using clinical variables, where the performance is found promising. The 1D CNN model could be a useful tool for detecting the risk of mortality and developing treatment plans in a timely manner.

CLINICAL IMPACT

The findings indicate that using both Heparin and Exnox for treatment is typically the most useful factor in predicting a patient's chances of survival from COVID-19. Moreover, our predictive model shows that the combination of AI and clinical data can be applied to point-of-care services through fast-learning healthcare systems.

Thromboprophylaxis in Hospitalized Non-Critically Ill Patients With Mild-to-Moderate COVID-19 Infection: A Systematic Review and Meta-Analysis

The prevalence of venous thromboembolism is high in patients with COVID-19, despite prophylactic anticoagulation. The evidence that supports the preferred thromboprophylaxis regimen in non-critically ill patients with mild to moderate COVID-19 is still limited. Therefore, this systematic review and meta-analysis aimed to compare the clinical outcomes of hospitalized patients with mild to moderate COVID-19 who received standard thromboprophylaxis anticoagulation with intermediate to high prophylaxis regimens. We systematically searched MEDLINE and Embase databases for published studies until August 17th, 2022. We included studies on patients with mild to moderate COVID-19 who received thromboprophylaxis during their hospital stay. Patients who received standard prophylaxis dose "control group" were compared to patients who received intermediate to high prophylaxis "intervention group". Random effect models were used when pooling crude numbers and adjusted effect estimates of study outcomes. A comprehensive analysis was conducted, encompassing seven studies involving a total of 1931 patients. The risk of all-cause thrombosis was not statistically different between the two groups (risk ratio [RR] 1.48, 95% confidence interval [CI] [0.11, 20.21]). The risk of minor bleeding was reported to be lower in patients who received intermediate to high prophylaxis (RR 0.64, 95% CI 0.21, 1.97), while had a higher risk of major bleeding compared with the standard prophylaxis (RR 1.40, 95% CI 0.43, 4.61); however, did not reach the statistical significance. The overall risk for all hospital mortality favored the utilization of intermediate to high doses over the standard thromboprophylaxis dosing (RR 0.47, 95%CI 0.29, 0.75). In medically ill patients with COVID-19, there is no difference between standard and intermediate to high prophylaxis dosing regarding thrombosis and bleeding. However, it appears that intermediate to high prophylaxis regimens are linked to additional survival benefits.

SARS-CoV-2 Infection Dysregulates Host Iron (Fe)-Redox Homeostasis (Fe-R-H): Role of Fe-Redox Regulators, Ferroptosis Inhibitors, Anticoagulants, and Iron-Chelators in COVID-19 Control

Severe imbalance in iron metabolism among SARS-CoV-2 infected patients is prominent in every symptomatic (mild, moderate to severe) clinical phase of COVID-19. Phase-I - Hypoxia correlates with reduced O₂ transport by erythrocytes, overexpression of HIF-1α, altered mitochondrial bioenergetics with host metabolic reprogramming (HMR). Phase-II - Hyperferritinemia results from an increased iron overload, which triggers a fulminant proinflammatory response - the acute cytokine release syndrome (CRS). Elevated cytokine levels (i.e. IL6, TNFα and CRP) strongly correlates with altered ferritin/TF ratios in COVID-19 patients. Phase-III - Thromboembolism is consequential to erythrocyte dysfunction with heme release, increased prothrombin time and elevated D-dimers, cumulatively linked to severe coagulopathies with life-threatening outcomes such as ARDS, and multi-organ failure. Taken together, Fe-R-H dysregulation is implicated in every symptomatic phase of COVID-19. Fe-R-H regulators such as lactoferrin (LF), hemoxygenase-1 (HO-1), erythropoietin (EPO) and hepcidin modulators are innate bio-replenishments that sequester iron, neutralize iron-mediated free radicals, reduce oxidative stress, and improve host defense by optimizing iron metabolism. Due to its pivotal role in 'cytokine storm', ferroptosis is a potential intervention target. Ferroptosis inhibitors such as ferrostatin-1, liproxstatin-1, quercetin, and melatonin could prevent mitochondrial lipid peroxidation, up-regulate antioxidant/GSH levels and abrogate iron overload-induced apoptosis through activation of Nrf2 and HO-1 signaling pathways. Iron chelators such as heparin, deferoxamine, caffeic acid, curcumin, α-lipoic acid, and phytic acid could protect against ferroptosis and restore mitochondrial function, iron-redox potential, and rebalance Fe-R-H status. Therefore, Fe-R-H restoration is a host biomarker-driven potential combat strategy for an effective clinical and post-recovery management of COVID-19.

Reduced risk of death in people with SARS-CoV-2 infection treated with remdesivir: a nested case-control study

INTRODUCTION

Since the start of the SARS-CoV-2 pandemic, several treatment options have been proposed (e.g. steroids, heparin, antivirals and monoclonal antibodies). Remdesivir was the first antiviral approved for the treatment of COVID-19, even though controversial evidence exists concerning the efficacy. Therefore, we aimed to conduct a study to evaluate whether the use of remdesivir was associated with lower mortality in patients with COVID-19.

METHODS

We conducted a nested case-control study of a retrospective cohort collecting medical records of people with SARS-CoV-2 infection admitted in the infectious Disease Unit of Sassari University Hospital (S.C. Clinica di Malattie Infettive, AOU di Sassari, Italy), or in the Infectious Disease Unit of Foggia (AOU "Ospedali Riuniti" Foggia), between 1 July 2020 and 10 November 2021. The outcome considered was death; thus, we matched death (cases) to survivors (controls) by sex and age (1:1).

RESULTS

We included in the study 342 patients, with 171 deaths (cases) and 171 survivors (controls). Remdesivir was administered to 60 people in the control group and to 18 people in the case group (35.1% vs. 10.5%, p < .0001). In the multivariate analysis, treatment with remdesivir and heparin was associated with lower mortality (OR: 0.19 [95% CI :0.10-0.38], p <.0001; OR: 0.39 [95% CI: 0.21-0.74] p = .004, respectively). On the contrary, diabetes, oxygen therapy and CPAP/NIV were associated with higher mortality.

CONCLUSION

Our study showed lower mortality in people with SARS-CoV-2 infection treated with remdesivir.

Not Just Anticoagulation—New and Old Applications of Heparin

In recent decades, heparin, as the most important anticoagulant drug, has been widely used in clinical settings to prevent and treat thrombosis in a variety of diseases. However, with in-depth research, the therapeutic potential of heparin is being explored beyond anticoagulation. To date, heparin and its derivatives have been tested in the protection against and repair of inflammatory, antitumor, and cardiovascular diseases. It has also been explored as an antiangiogenic, preventive, and antiviral agent for atherosclerosis. This review focused on the new and old applications of heparin and discussed the potential mechanisms explaining the biological diversity of heparin.

A natural heparinoid from mollusc Meretrix lusoria: Purification, structural characterization, and antithrombotic evaluation

Heparinoid, a sulfate polysaccharide derived from marine organisms was attracted largely attention due to its versatile activities. A naturally occurring heparinoid (M2) that was extracted from the mollusk Meretrix lusoria and used in this investigation shown strong antithrombotic action. UV-Vis, FT-IR, SAX-HPLC, and NMR were used to explore the structural characteristics of M2, results indicated that M2 similar with heparin, its average molecular weight was 22.58 kDa. Which was primarily made up of→4)-α-IdoA2S-(1→4)-α-GlcNS6S-(1→ (31.19%), →4)-β-GlcA-(1→4)-α-GlcNAc (1→ (23.21%), →4)-β-GlcA-(1→4)-α-GlcNS (1→ (13.87%), →4)-α-IdoA2S-(1→4)-α-GlcNS (1→ (8.95%), →4)-β-GlcA-(1→4)-α-GlcNAc6S (1→ (7.39%) and →4)-β-GlcA-(1→4)-α-GlcNS6S (1→ (7.63%). The antithrombotic activity of M2 was evaluated using measurements of the anticoagulant effect in vitro and the fibrinolytic capability in vitro and in vivo, and M2 has 122.4 U/mg of anticoagulant activity and 1.41 U/mg of fibrinolytic activity, respectively. Additionally, a mouse tail-cutting model was used to assess the bleeding effect in real time, it found that M2 had a reduced hemorrhagic risk than heparin. Consequently, M2 could be exploited to develop functional foods or medications with antithrombotic properties.

Efficacy and safety of intensified versus standard prophylactic anticoagulation therapy in patients with Covid-19: a systematic review and meta-analysis

Background

Randomized controlled trials (RCTs) have reported inconsistent effects from intensified anticoagulation on clinical outcomes in coronavirus disease 2019 (COVID-19). We performed an aggregate data meta-analysis from available trials to quantify effect on nonfatal and fatal outcomes and identify subgroups who may benefit.

Methods

We searched multiple databases for RCTs comparing intensified (intermediate or therapeutic dose) vs prophylactic anticoagulation in adults with laboratory-confirmed COVID-19 through 19 January 2022. We used random-effects meta-analysis to estimate pooled risk ratios for mortality, thrombotic, and bleeding events (at end of follow-up or discharge) and performed subgroup analysis for clinical setting and dose of intensified anticoagulation.

Results

Eleven RCTs were included (N = 5873). Intensified vs prophylactic anticoagulation was not associated with a mortality reduction up to 45 days (risk ratio [RR], 0.93 [95% confidence interval {CI}, .79–1.10]). There was a possible signal of mortality reduction for non–intensive care unit (ICU) patients, although with low precision and high heterogeneity (5 studies; RR, 0.84 [95% CI, .49–1.44]; I² = 75%). Risk of venous thromboembolism was reduced (RR, 0.53 [95% CI, .41–.69]; I² = 0%), with effect driven by therapeutic rather than intermediate dosing (interaction P = .04). Major bleeding was increased with intensified anticoagulation (RR, 1.73 [95% CI, 1.17–2.56]) with no interaction for dosing and clinical setting.

Conclusions

Intensified anticoagulation has no effect on mortality among hospitalized adults with COVID-19 and is associated with increased bleeding risk. The observed reduction in venous thromboembolism risk and trend toward reduced mortality in non-ICU settings requires exploration in additional RCTs.

Clinical Trials Registration. CRD42021273449 (PROSPERO).

Pharmacokinetic, Hemostatic, and Anticancer Properties of a Low-Anticoagulant Bovine Heparin

Heparin is a centennial anticoagulant drug broadly employed for treatment and prophylaxis of thromboembolic conditions. Although unfractionated heparin (UFH) has already been shown to have remarkable pharmacological potential for treating a variety of diseases unrelated with thromboembolism, including cancer, atherosclerosis, inflammation, and virus infections, its high anticoagulant potency makes the doses necessary to exert non-hemostatic effects unsafe due to an elevated bleeding risk. Our group recently developed a new low-anticoagulant bovine heparin (LABH) bearing the same disaccharide building blocks of the UFH gold standard sourced from porcine mucosa (HPI) but with anticoagulant potency approximately 85% lower (approximately 25 and 180 Heparin International Units [IU]/mg). In the present work, we investigated the pharmacokinetics profile, bleeding potential, and anticancer properties of LABH administered subcutaneous into mice. LABH showed pharmacokinetics profile similar to HPI but different from the low-molecular weight heparin (LMWH) enoxaparin and diminished bleeding potential, even at high doses. Subcutaneous treatment with LABH delays the early progression of Lewis lung carcinoma, improves survival, and brings beneficial health outcomes to the mice, without the advent of adverse effects (hemorrhage/mortality) seen in the animals treated with HPI. These results demonstrate that LABH is a promising candidate for prospecting new therapeutic uses for UFH.

Effects of low molecular weight heparin and fondaparinux on mortality, hemorrhagic and thrombotic complications in COVID-19 patients

Background:

Coronavirus disease 2019 (COVID-19) is associated with increased thrombosis prevalence. However, there are insufficient data supporting the appropriate anticoagulation dose in COVID-19.

Objective:

We aim to systematically assess the currently available data regarding the effects of different dosing regimens of low molecular weight heparin and/or fondaparinux (LMWH/F) on mortality risk as well as the risk of arterial/venous thrombotic events and hemorrhagic complications in confirmed COVID-19 cases.

Design:

We conducted a living systematic review and meta-analysis on the effects of different LMWH/F doses on mortality, thrombotic and hemorrhagic events in COVID-19 patients.

Data Sources and Methods:

MEDLINE, Scopus, Embase, Cochrane Library, Cochrane COVID-19 study register, European Union Drug Regulating Authorities Clinical Trials Database, and ClinicalTrials.gov were searched to detect observational cohort studies and randomized-controlled clinical trials (RCTs) comparing difference doses of LMWH/F among confirmed COVID-19 cases.

Results:

Thirty-one eligible studies (6 RCTs and 25 cohort studies) with 11,430 hospitalized patients were included. No association was found between LMWH/F and mortality during the following comparisons: (1) no LMWH/F versus any LMWH/F; (2) prophylactic versus higher than prophylactic LMWH/F; (3) prophylactic versus therapeutic LMWH/F; (4) intermediate versus therapeutic LMWH/F; and (5) lower than therapeutic versus therapeutic LMWH/F. Mortality was higher in patients receiving prophylactic versus intermediate LMWH/F (OR = 2.01; 95% CI: 1.19–3.39). However, this effect was mostly driven by observational data. No associations were detected between the intensity of LMWH/F and the risk of thrombotic and hemorrhagic events, except the lower risk for hemorrhage in patients on prophylactic compared to higher LMWH/F doses.

Conclusion:

The risk for all-cause mortality was higher in patients receiving prophylactic LMWH/F compared to those on an intermediate dose of LMWH/F, based on observational data. These results should be interpreted in light of the moderate quality and heterogeneity of the included studies.

Registration:

The study protocol has been registered in the International Prospective Register of Ongoing Systematic Reviews PROSPERO (Registration number: CRD42021229771).

COVID 19 pandemic challenges and their management: A review of medicines, vaccines, patents and clinical trials with emphasis on psychological health issues

The SARS‐CoV‐2 (COVID 19) paroxysm is a dominant health exigency that caused significant distress, affecting physical and mental health. Increased mortality, a stressed healthcare system, financial crisis, isolation, and new living and working styles enhanced societal commiseration leading to poor health outcomes. Though people try to maintain good physical health but unfortunately the mental affliction is still ignored. Poor psychological health has emerged as a burgeoning social issue and demands attention. Henceforth, the fundamental objective of this review article is to collate information about COVID-linked physical and psychological agony in diverse population groups with related symptoms and accessible diagnosis techniques. Recent studies have unraveled the fragile mental states of people who have either contracted COVID 19 or had near and dear ones falling prey to it. The impact of the epidemic on the human mind both in short and long-term, with possible risk and preventive factors together with suggested solutions for maintaining good health have also been discussed here. It also enlists the available medications, vaccines and investigational research in the form of patents and clinical trials. This article can be taken as an updated information sheet for COVID 19, accompanied by its management techniques with special emphasis on coping strategies for mental health. Further, it may also assist the policymakers to devise approaches that could enable the public to overcome the pandemic-driven adversity not only in the given situation but also futuristically.

High-mobility group box 1 (HMGB1) in COVID-19: extrapolation of dangerous liaisons

High-mobility group box 1 (HMGB1), a multifunctional nuclear protein, exists mainly within the nucleus of all mammal eukaryotic cells. It is actively secreted by the necrotic cells as a response to the inflammatory signaling pathway. HMGB1 binds to receptor ligands as RAGE, and TLR and becomes a pro-inflammatory cytokine with a robust capacity to trigger inflammatory response. It is a critical mediator of the pathogenesis of systemic inflammation in numerous inflammatory disorders. Release of HMGB1 is associated with different viral infections and strongly participates in the regulation of viral replication cycles. In COVID-19 era, high HMGB1 serum levels were observed in COVID-19 patients and linked with the disease severity, development of cytokine storm (CS), acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). SARS-CoV-2-induced cytolytic effect may encourage release of HMGB1 due to nuclear damage. Besides, HMGB1 activates release of pro-inflammatory cytokines from immune cells and up-regulation of angiotensin I-converting enzyme 2 (ACE2). Therefore, targeting of the HMGB1 pathway by anti-HMGB1 agents, such as heparin, resveratrol and metformin, may decrease COVID-19 severity. HMGB1 signaling pathway has noteworthy role in the pathogenesis of SARS-CoV-2 infections and linked with development of ALI and ARDS in COVID-19 patients. Different endogenous and exogenous agents may affect release and activation of HMGB1 pathway. Targeting of HMGB1-mediated TLR2/TLR4, RAGE and MAPK signaling, might be a new promising drug candidate against development of ALI and/or ARDS in severely affected COVID-19 patients.

Enoxaparin augments alpha-1-antitrypsin inhibition of TMPRSS2, a promising drug combination against COVID-19

The cell surface serine protease Transmembrane Protease 2 (TMPRSS2) is required to cleave the spike protein of SARS-CoV-2 for viral entry into cells. We determined whether negatively-charged heparin enhanced TMPRSS2 inhibition by alpha-1-antitrypsin (AAT). TMPRSS2 activity was determined in HEK293T cells overexpressing TMPRSS2. We quantified infection of primary human airway epithelial cells (hAEc) with human coronavirus 229E (HCoV-229E) by immunostaining for the nucleocapsid protein and by the plaque assay. Detailed molecular modeling was undertaken with the heparin-TMPRSS2-AAT ternary complex. Enoxaparin enhanced AAT inhibition of both TMPRSS2 activity and infection of hAEc with HCoV-229E. Underlying these findings, detailed molecular modeling revealed that: (i) the reactive center loop of AAT adopts an inhibitory-competent conformation compared with the crystal structure of TMPRSS2 bound to an exogenous (nafamostat) or endogenous (HAI-2) TMPRSS2 inhibitor and (ii) negatively-charged heparin bridges adjacent electropositive patches at the TMPRSS2-AAT interface, neutralizing otherwise repulsive forces. In conclusion, enoxaparin enhances AAT inhibition of both TMPRSS2 and coronavirus infection. Such host-directed therapy is less likely to be affected by SARS-CoV-2 mutations. Furthermore, given the known anti-inflammatory activities of both AAT and heparin, this form of treatment may target both the virus and the excessive inflammatory consequences of severe COVID-19.

Efficacy and safety of intensified versus standard prophylactic anticoagulation therapy in patients with Covid-19: a systematic review and meta-analysis

Background

Randomised controlled trials (RCTs) have reported inconsistent effects from intensified anticoagulation on clinical outcomes in Covid-19. We performed an aggregate data meta-analysis from available trials to quantify effect on non-fatal and fatal outcomes and identify subgroups who may benefit.

Methods

We searched multiple databases for RCTs comparing intensified (intermediate or therapeutic dose) versus standard prophylactic dose anticoagulation in adults with laboratory-confirmed Covid-19 through 19 January 2022. The primary efficacy outcome was all-cause mortality at end of follow-up or discharge. We used random effects meta-analysis to estimate pooled risk ratios for mortality, thrombotic, and bleeding events, and performed subgroup analysis for clinical setting and dose of intensified anticoagulation.

Results

Eleven RCTs were included (n = 5873). Intensified anticoagulation was not associated with a reduction in mortality for up to 45 days compared with prophylactic anticoagulation: 17.5% (501/2861) died in the intensified anticoagulation group and 18.8% (513/2734) died in the prophylactic anticoagulation group, relative risk (RR) 0.93; 95%CI, 0.79 - 1.10. On subgroup analysis, there was a possible signal of mortality reduction for inpatients admitted to general wards, although with low precision and high heterogeneity (5 studies; RR 0.84; 95% CI, 0.49 - 1.44; I ² = 75%) and not significantly different to studies performed in the ICU (interaction P = 0.51). Risk of venous thromboembolism was reduced with intensified anticoagulation compared with prophylaxis (8 studies; RR 0.53, 95%CI 0.41 - 0.69; I ² = 0%). This effect was driven by therapeutic rather than intermediate dosing on subgroup analysis (interaction P =0.04). Major bleeding was increased with use of intensified anticoagulation (RR 1.73, 95% CI 1.17 - 2.56) with no interaction for dosing and clinical setting.

Conclusion

Intensified anticoagulation has no effect on short term mortality among hospitalised adults with Covid-19 and is associated with increased risk of bleeding. The observed reduction in venous thromboembolism risk and trend towards reduced mortality in non-ICU hospitalised patients requires exploration in additional RCTs.

Summary

In this aggregate data meta-analysis, use of intensified anticoagulation had no effect on short term mortality among hospitalised adults with Covid-19 and was associated with increased risk of bleeding.

Low molecular weight heparin reduces arterial blood lactic acid content and increases estimated glomerular filtration rate in patients with moderate Covid-19 pneumonia

Background:

Coronavirus disease 2019 (Covid-19) remains a serious health threat worldwide. We aimed to investigate whether low molecular weight heparin (LMWH) can promote organ function recovery in moderate Covid-19 pneumonia patients.

Methods:

We initiated an LMWH protocol in Covid-19 patients with increased D-dimer, body mass index >30 kg/m² or a history of diabetes from January 18, 2020 at Shanghai Public Health Clinical Center. In this retrospective study, we assigned moderate Covid-19 pneumonia patients admitted between January 18th and April 18, 2020 receiving the LMWH protocol to the LMWH group. Moderate patients who met the inclusion criteria but did not receive LMWH protocol were included in the control group by 1:2 propensity score matching. General clinical information, indicators for renal function, arterial blood gas analyses, arterial blood lactic acid content (mmol/L), and coagulation indexes at 0 day, 3 days, 7 days, and 11 days after admission were recorded and compared between the two groups.

Results:

There were 41 patients in the LMWH group and 82 patients in the control group. General information in both groups were similar. Compared to the control group, the arterial blood lactic acid content (mmol/L) at day 11 (1.3 [1.1, 1.7] vs. 1.2 [0.9, 1.3], P = 0.016) was reduced in the LMWH group. The estimated glomerular filtration rate (eGFR) in the LMWH group was higher than that in the control group at day 7 (108.54 [89.11, 128.17] vs. 116.85 [103.39, 133.47], P = 0.039) and day 11 (113.74 [94.49, 126.34] vs. 128.31 [112.75, 144.12], P = 0.003). The serum creatinine levels (Scr) in the LMWH group were lower than that in the control group at day 7 (62.13 [51.47, 77.64] vs. 55.49 [49.50, 65.75], P = 0.038) and day 11 (63.35 [50.17, 75.73] vs. 51.62 [44.62, 61.24], P = 0.005).

Conclusions:

LMWH treatment can reduce arterial blood lactic acid levels and improve eGFR in moderate Covid-19 pneumonia patients. Randomized controlled trials are warranted to further investigate this issue.

Trial registration:

ChiCTR.org.cn, ChiCTR2000034796.

The Future of the COVID-19 Pandemic: How Good (or Bad) Can the SARS-CoV2 Spike Protein Get?

Severe acute respiratory syndrome virus 2 (SARS-CoV2) has infected an estimated 400 million people world-wide, causing approximately 6 million deaths from severe coronavirus disease 2019 (COVID-19). The SARS-CoV2 Spike protein plays a critical role in viral attachment and entry into host cells. The recent emergence of highly transmissible variants of SARS-CoV2 has been linked to mutations in Spike. This review provides an overview of the structure and function of Spike and describes the factors that impact Spike’s ability to mediate viral infection as well as the potential limits to how good (or bad) Spike protein can become. Proposed here is a framework that considers the processes of Spike-mediated SARS-CoV2 attachment, dissociation, and cell entry where the role of Spike, from the standpoint of the virus, is to maximize cell entry with each viral-cell collision. Key parameters are identified that will be needed to develop models to identify mechanisms that new Spike variants might exploit to enhance viral transmission. In particular, the importance of considering secondary co-receptors for Spike, such as heparan sulfate proteoglycans is discussed. Accurate models of Spike-cell interactions could contribute to the development of new therapies in advance of the emergence of new highly transmissible SARS-CoV2 variants.

[Potentially useful drugs in the treatment of COVID-19 in Primary Care]

The consequences of the SARS-CoV-2 pandemic have exceeded any forecast made. Today we know that the level of severity of the infection in its initial stages will correspond to the evolution and the presence of sequelae in the future. There are no specific treatments that have shown sufficient evidence to allow their recommendation, especially in the mild-moderate stages of the disease. The anti-Covid vaccination is showing clear benefits, both in the prevention of the disease and in its evolution, with the consequent improvement in the numbers of those affected by the pandemic. The use of different drugs used in other indications has been proposed as possible beneficial treatments for COVID-19 that, if used, will be prescribed individually taking into account the characteristics and situation of the patient, the evolutionary phase of the disease as well as well as the limitations of the lack of evidence in its administration.