Chloroquine and COVID-19 – a potential game changer?

The novel coronavirus SARS-CoV-2, causing the disease COVID-19, first emerged in Wuhan, China in December 2019 and has now spread to 203 countries or territories, infected over 2 million people and caused over 133,000 deaths. There is an urgent need for specific treatments. One potential treatment is chloroquine and its derivatives, including hydroxychloroquine, which have both antiviral and anti-inflammatory effects. These compounds are effective against SARS-CoV-2 in vitro, but in vivo data are lacking. Although some encouraging outcomes have been reported, and these results have been received enthusiastically, we recommend careful and critical evaluation of current evidence only when all methods and data are available for peer review. Chloroquine is safe and cheap. However, further evidence from coordinated multicentre trials is required before it can be confidently said whether it is effective against the current pandemic

The Renin-Angiotensin system – a therapeutic target in COVID-19?

COVID-19, caused by infection with SARS-CoV-2, is a disease characterised by cough, fever and fatigue, which progresses to life-threatening lung injury in approximately 5% of patients. The SARS-CoV-2 virus enters the cell via ACE2. ACE2 is a component of the renin–angiotensin system (RAS) which has an important counterregulatory effect on the classical ACE-dependent pathway. Several antihypertensives increase ACE2 expression or activity, leading to concern that this may facilitate SARS-CoV-2 entry and worsen COVID-19 disease. However, ACE2 is protective against lung injury while ANG II (which is catabolised by ACE2) is associated with lung injury both in mice and humans. We propose that medications which inhibit the RAS ACE-dependent pathway may be beneficial in treating COVID-19 and should be explored in animal models and clinical trials. Here we give an overview of the RAS pathway with respect to COVID-19 and argue that strategies which manipulate this pathway might reduce the destructive lung manifestations of COVID-19 and improve patient outcomes

Thrombotic risk in COVID-19: a case series and case-control study

Background: A possible association between COVID-19 infection and thrombosis, either as a direct consequence of the virus or as a complication of inflammation, is emerging in the literature. Data on the incidence of venous thromboembolism (VTE) is extremely limited. Methods: We describe 3 cases of thromboembolism refractory to heparin treatment, the incidence of VTE in an inpatient cohort, and a case-control study to identify risk factors associated with VTE. Results: We identified 274 confirmed (208) or probable (66) COVID-19 patients. 21 (7.7%) were diagnosed with VTE. D-dimer was elevated in both cases (confirmed VTE) and controls (no confirmed VTE) but higher levels were seen in confirmed VTE cases (4.1vs 1.2 µg/mL P <0.001). Conclusion: Incidence of VTE is high in patients hospitalised with COVID-19. Urgent clinical trials are needed to evaluate the role of anticoagulation in COVID-19. Monitoring of D-dimer and anti-factor Xa levels may be beneficial in guiding management

Letter to the editor: acute myeloid leukemia cells exhibit selective down-regulation of DNMT3A isoform 2

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A dynamic multi-compartmental model of DNA methylation with demonstrable predictive value in hematological malignancies

Recent advances have highlighted the central role of DNA methylation in leukemogenesis and have led to clinical trials of epigenetic therapy, notably hypomethylating agents, in myelodysplasia and acute myeloid leukemia. However, despite these advances, our understanding of the dynamic regulation of the methylome remains poor. We have attempted to address this shortcoming by producing a dynamic, six-compartmental model of DNA methylation levels based on the activity of the Dnmt methyltransferase proteins. In addition, the model incorporates the recently discovered Tet family proteins which enzymatically convert methylcytosine to hydroxymethylcytosine. A set of first order, partial differential equations comprise the model and were solved via numerical integration. The model is able to predict the relative abundances of unmethylated, hemimethylated, fully methylated, and hydroxymethylated CpG dyads in the DNA of cells with fully functional Dnmt and Tet proteins. In addition, the model accurately predicts the experimentally measured changes in these abundances with disruption of Dnmt function. Furthermore, the model reveals the mechanism whereby CpG islands are maintained in a hypomethylated state via local modulation of Dnmt and Tet activities without any requirement for active demethylation. We conclude that this model provides an accurate depiction of the major epigenetic processes involving modification of DNA

Haemolytic anaemia: don’t leave it out in the cold

This clinical case highlights the diagnostic odyssey of an adolescent girl presenting to A&E with non-specific headaches and chest pain. The case will describe the steps in decision making from admission to follow-up