Background: After the outbreak of a novel coronavirus (i.e. SARS COV2) in China and its diffusion around the world, great attentions was reserved to the increased incidence of venous thromboembolism in these patients. A specific antiviral action of heparins toward SARS COV2 has been reported in vitro such as a well know action of heparins to prevent VTE in inpatients with infective disease has already been reported since several years. Yet, because fondaparinux represent the pharmacological antithrombotic active sequence of all heparins and because its clinical indication o prevent VTE in inpatients is similar to heprains, we realized a retrospective analysis in inpatients with SARS COV2 on the incidence of VTE during pharmacological prophylaxis with enoxaparin or fondaparinux. This retrospective analysis was named FONDENOXAVID. Methods: We conducted a retrospective cohort study that used patients with SARS COV2 during the Italian outbreak from February 18, 2020 to April 30, 2020. Our aim was to compare the clinical characteristics, prophylactic treatment and outcomes in inpatients positive to SARS COV2 at risk to develop venous thromboembolism, in particular venous thrombosis with or without pulmonary embolism, during in-hospital primary thromboprophylaxis with enoxaparin (40 mg or 60 mg once daily) or fondaparinux (2.5 mg once daily). Statistical analysis was conducted with using MatLab R2016B and eventually ad hoc functions. Results: There were not significative differences in clinical characteristics between patients that used enoxaparin or fondaparinux as thromboprpophylaxis for SARS COV2. The cumulative incidence of thrombotic events was not different in patients that used enoxaparin or fondaparinux as thromboprpophylaxis. No differences were found also in d-dimer and fibrinogen levels test at the admission and after 3 weeks as markers of prolonged inflammation due to SARS COV2. Discussion: The increased incidence of VTE in vivo has been reported in several studies although prophylaxis with low molecular weight heparin was conducted in some of them. The clinical indication to prevent VTE was similar for heparins and fondaparinux. In our results a non-inferiority to prevent VTE was recorded when inpatients with SARS COV2 were treated with prophylactic doses of enoxaparin or fondaparinux according to international guidelines. The incidence of VTE in this retrospective analysis showed that Fondaparinux at fixed doses of 2.5 mg daily was not inferior to enoxaparin (4000 UI daily). Our results testify that fondaparinux and enoxaparin showed the same efficacy to reduce the incidence of VTE in inpatients with SARS COV2.

SARS-CoV-2 attachment and entry inside mammalian cells is mainly mediated by human angiotensin-converting enzyme 2 (ACE2) and its interaction with spike protein. However, it is well known that spike protein also interacts with other molecules like glycosaminoglycans (GAG), e.g., heparan sulfate (HS) or Enoxaparin (EX), which are linear, anionically charged polysaccharides known for their biological activities. The mode of action of these two polysaccharides is to bind spike protein to block the interaction with ACE2 receptors. This study aimed to assess a model capable of confirming the activity of these GAGs in both the wild-type strain of SARS-CoV-2 and its variants, such as the highly variable BA.2.86. This was achieved by combining in silico modeling with in vitro determination using BacMam technology. The results showed the antiviral activity of HS and EX both in vitro and through the in-silico analysis, reconciling conflicting findings from recent studies on the cellular entry of SARS-CoV-2. In conclusion, it is possible to highlight the ability of these molecules to circumvent the high variability of SARS-CoV-2, providing valuable insights into intervention strategies targeting cell entry mechanisms and establishing a safe in vitro model.

Abstract: This is a retrospective study of patients admitted to Jackson Hospital, Montgomery, Alabama with a diagnosis of COVID-19 from January 1, 2021, to February 15, 2022. The independent variable used in the models were patient sex, age, race, BMI category, daily D-dimer categories, categories of anticoagulation doses (Enoxaparin 40 mg VS. Enoxaparin 80 mg VS Enoxaparin 1mg/kg or equivalent), bleeding episodes, and vaccination status. The three different categories of anticoagulation doses were considered for the purpose of the study. Results: The study reviewed a total of one hundred (100) hospitalized patients. Intermediate-dose anticoagulation was found to be the optimal dose as only fourteen percent (14%) patients died compared to a thirty-six percent (36%) and fifty percent (57%) death rate among those treated with low-dose and high-dose anticoagulation, respectively. The multivariate linear regression model predicting patient oxygen requirements revealed D-Dimer and bleeding status to be statistically significant predictors with a p value of <0.01. For the patients who had a D-dimer value ≥ 2 µg/mL, the oxygenation requirement was predicted to be 31 L higher than those with a D-dimer <2 µg/mL (99% CI; p<0.01). When mean D-dimer and corresponding oxygen requirements were calculated per hospitalization days category, the D-dimer levels and oxygen requirements were noted to follow the same trends indicating both values tended to increase and decrease simultaneously. Conclusion: The study concludes daily D-dimer trends can predict COVID-19 patient survival or daily oxygen requirements indicating D-dimer can be the miracle molecule for COVID-19 prognosis.