So far the mice seem to like the blood and have been described by the research team as “indifferent” to it. Hemerythrin is apparently the key, a protein derived from the blood of two marine invertebrates seen in the picture below. They are sipunculids seen on the left and brachiopods seen on the right. In these invertebrates the hemerythrin works like our hemoglobin to transfer and store oxygen, but it exhibits a lower stress-related reactivity than hemoglobin. This may be the reason it is working with mice as a blood substitute without causing rejection or other bad side effects. The big question is will it work on humans?

As a regular blood donor myself I have done research on this subject over the years and have seen many attempts fail. It will be interesting to see if this one turns out to be the real deal.

The researchers intend to do far more extensive testing on mice before considering human clinical trials. But how appropriate that this announcement comes out of Transylvania on the eve of Halloween.