Thursday, July 2, 2020

Evidence for the Role of Dramatically Increased Numbers of Megakaryocytes Associated with Blood Clots in COVID-19

Disturbing new evidence is emerging from the post-mortems of patients who have died from COVID-19 disease that demonstrates the presence of blood clots (thrombi). These thrombi have been shown in this extensive study to be present in major organs and systems including the lungs, heart, kidney, and brain. 

In addition, a particular cell type referred to as a megakaryocyte has also been found associated with these thrombi. Platelets (thrombocytes) are often associated with thrombi. Platelets, themselves, are generated from so-called progenitor, promegakaryocytes that reside and multiply within the bone marrow. Megakaryocytes are formed from promegakaryocytes and from these megakaryocytes are formed that ultimately break up to produce platelets (see diagram below) that are released into the blood and tissues. The fact that megakaryocytes are evidenced in higher than usual numbers in tissues such as lung, heart, kidney, and brain in patients with COVID-19 disease is a cause for concern.





According to an abstract published by Lancet – a prestigious medical publication – and authored by Amy V. Rapkiewicz, “In seven patients (four female), regardless of anticoagulation status, all autopsies demonstrated platelet-rich thrombi in the pulmonary, hepatic, renal, and cardiac microvasculature. Megakaryocytes were seen in higher than usual numbers in the lungs and heart. Two cases had thrombi in the large pulmonary arteries, where casts conformed to the anatomic location. Thrombi in the IVC were not found, but the deep leg veins were not dissected. Two cases had cardiac venous thrombosis with one case exhibiting septal myocardial infarction associated with intramyocardial venous thrombosis, without atherosclerosis.” In addition, The presence of circulating megakaryocytes on autopsy in various organs was also found and thoroughly studied.

The fact that thrombi have been found in the post-mortems of a significant number of patients who died of COVID-19 disease can account for systemic organ failure in vital organs such as lung, kidneys and heart and such a set of conditions could easily lead to subsequent death.

These data are exceedingly troubling and leaves researchers with a profound question – how does COVID-19 infection trigger such a disastrous response?

The Apparent Efficacy of the Steroid Drug Dexamethasone as Therapy for COVID-19 Patients

As medical professionals, epidemiologists, immunologists, and molecular biologists work in the midst of the COVID-19 pandemic, many aspects of the biology of this virus are being studied and as a result, new understandings are emerging.

It seems that patients with advanced disease that require intervention using a ventilator may be suffering from a hyper-active immune response. In such cases, the use of steroid-based anti-inflammatory drugs may prove efficacious.

An extremely encouraging report from the highly respected Science journal, Nature, has shown the results of a trial study using the proven steroid drug Dexamethasone.

According to the report, the results have indicated that, “An inexpensive and commonly used steroid can save the lives of people seriously ill with COVID-19, a randomized, controlled clinical trial in the United Kingdom has found. The drug, called dexamethasone, is the first shown to reduce deaths from the coronavirus that has killed more than 440,000 people globally. In the trial, it cut deaths by about one-third in patients who were on ventilators because of coronavirus infection.”

This study was expansive involving 2100 participants who received the drug at what is considered a low to moderate dose – 6 milligrams (mg.) per day for 10 consecutive days. The results from the patients were then compared to the results from 4300 patients who received standard care for COVID-19 infection.

Although the drug had no noticeable impact on patients showing no severe symptoms, the positive effect was most striking on patients on ventilators and even on those undergoing just oxygen therapy (not on ventilators) where the rate of death was reduced by 20%.

These are, indeed, encouraging results.