I think what you've descibed would be classed as active content, not dynamic content. Dynamic content tends to be used as a concept in spam mailshots where a standard e-mail is fettled for individual users automatically based on held data - e.g. purchase history / enquiry history / address.....
Now to your query
In theory yes it should be possible, but what are you trying to achieve?
Most e-mails are rapidly lost in the noise when newer ones arrive. For your plan to work the recipients would have to be constantly searching for an old mail. However more fundamentally, any e-mail client worth using is going to block active content by default as a security measure. Active content in an e-mail is a security risk, and even if the e-mail client doesn't block it, the antivirus or firewall software will.
Conceptually none of your recipients are going to thank you for sending them an e-mail which is a very big security risk: active content = serious risk of malware