Red blood cell replacement, or nanobiotherapeutics with enhanced red blood cell functions?

Abstract

Why is this important?

Under normal circumstances, donor blood is the best replacement for blood. However, there are exceptions:

• During natural epidemics (e.g., HIV, Ebola, etc.) or man-made epidemics (terrorism, war, etc.), there is a risk of donor blood being contaminated, and donors being disqualified because they have contracted disease. Unlike red blood cells (RBCs), blood substitutes can be sterilized to remove infective agents.

• Heart attack and stroke are usually caused by obstruction of arterial blood vessels. Unlike RBCs, which are particulate, blood substitutes are in the form of a solution that can perfuse through obstructed vessels with greater ease to reach the heart and brain, as has been demonstrated in animal studies.

• Severe blood loss from injuries sustained during accidents, disasters, or war may require urgent blood transfusion that cannot wait for transportation to the hospital for blood group testing. Unlike RBCs, blood substitutes do not have specific blood groups, and can be administered on the spot.

• RBCs have to be stored under refrigeration for up to 42 days, and are thus difficult to transport and store in times of disaster and at the battlefront. Blood substitutes can be stored at room temperature for more than 1 year, compared to the RBC shelf life of 1 day, at room temperature.

• In cases of very severe hemorrhagic shock, there is usually a safety window of 60 min for blood replacement, beyond which there could be problems related to irreversible shock. Animal studies show that a particular type of blood substitute, with enhanced RBC enzymes, may be able to prolong the duration of the safety window.

Keywords: :

• donor blood
• blood substitiute
• oxygen carrier
• antioxidant
• carbon dioxide transport
• hemoglobin
• catalase
• superoxide dismutase
• carbonic anhydrase
• irreversible hemorrhagic shock

Acknowledgements

This area of research at the author's laboratory is at present being supported by an operating grant of the Canada Blood Service/Canadian Institutes of Health Research that require the author to state that the opinions in this paper are those of the author and not necessarily of the grant-awarding agencies or the government of Canada. The author has no connection to any commercial organization.

Declaration of interest

The author reports no declaration of interest. The author alone is responsible for the content and writing of the paper.