TeachableMedicalNews article 04182020

Teachable moment in classrooms:

  1. chemical basis of life chapter – nucleotides that make up RNA
  2. cellular basis of life chapter – RNA production for cellular uses
  3. microbiology – corona viruses are RNA viruses

The news item:  A recent article discussed clinical trial results of the drug remdesivir:

Report: Covid-19 patients recovering quickly after getting experimental drug | CNN

Covid-19 patients who are getting an experimental drug called remdesivir have been recovering quickly, with most going home in days, STAT News reported Thursday after it obtained a video of a conversation about the trial.

The news item mentions promising anecdotal information of the drug, and that it was found effective in animals against other coronavirus-based diseases.

So, Why Do I Care??  Have you been living under a rock in the last few months??? The coronavirus, SARS-CoV-2, responsible for the COVID 19 disease has so far infected over 2 million people, and caused over 154,000 deaths worldwide (on the date of this article). The virus attacks the respiratory system, and may cause pneumonia and respiratory failure.  The antiviral drug remdesivir holds promise as a possible treatment to lower the intensity, and perhaps, the lethality of the virus.

Plain English, Please!!! First, let’s talk about what remdesivir is. This drug is a relatively simple chemical; it is an adenosine nucleotide with some chemical changes made to it. In treated patients remdesivir is used instead of the natural adenosine for making new RNA strands, and the RNA making enzyme is slowed down by remdesivir. In addition, remdesivir in the cells shortens the RNA, and makes it difficult to degrade inside the cell.

Second, let’s talk about how could we disable this corona virus.  The SARS-CoV-2 virus has a life cycle, a series of events that need to happen to create new infectious viruses. It’s like operating your car. In order to go somewhere in your car, you have to go through a series of acts.  You have to open the car door, you have to put your key into the ignition switch, you have to turn your key to start the car, you have to release the hand brake, you have to put the transmission into gear, and then you have to push the gas pedal. The life cycle of the virus is made up of series of events; each event depends on the completion of the previous event, like driving your car. Antiviral drugs take aim at one such event in the life cycle, and by disabling one event, they prevent the completion of the rest of the cycle.

Third, let’s talk about where in the corona virus life cycle does remdesivir act. In order to make thousands of new infectious corona viruses, the genetic material (RNA) of the virus needs to be copied a thousand times. That copying is one step in the viral life cycle. Inside the remdesivir-treated cells that RNA copying is disrupted, because the RNA copier enzyme is slowed, the virus RNA is now shorter, and the misshapen RNA is hard to remove.  So, the new viruses with this abnormal RNA can’t hijack and damage other cells.  And, so the viral infection fizzles out.