For years researchers have tried to find the 'holy grail' of blood transfusion in the form of the ideal oxygen-carrying red cell substitute, a search that has eluded them to date.
- Blood substitutes (eMedicine, Medscape)
Not included in this blog is an early research pathway - chop 'em - whereby enzymes chop off A and B antigens and convert all red cells to group O cells. So far research has not led to practical use. Also see this paper from 21 years ago:
- Goldstein J. Conversion of ABO blood groups. Transfus Med Rev. 1989 Jul;3(3):206-12.
Scientists in many countries are working on developing synthetic blood from embryonic stem cells but Scotland has embarked on a project to produce blood on an industrial scale.
In 2009 the Scottish National Blood Transfusion Service in collaboration with several universities began a trial to provide an unlimited supply of group O Rh negative red cells for emergency transfusions. The project has just received a further injection of funds.
Research will require cross-disciplinary teams involving medicine, bioprocess technology, and engineering.
CONVERT 'EM
Researchers in Hamilton, Ontario, Canada demonstrated the ability to generate hematopoietic progenitor and mature blood cells directly from human skin fibroblasts. News reports:
- McMaster researchers beat world in blood race
- Cellular 'alchemy' converts skin into blood
- Skin into blood
- Szabo E, Rampalli S, Risueño RM, Schnerch A, Mitchell R, Fiebig-Comyn A, Levadoux-Martin M, Mickie Bhatia M. Direct conversion of human fibroblasts to multilineage blood progenitors. Nature 2010; Published online 7 Nov. 2010.
The McMaster team will also investigate converting excess, unwanted fat cells into blood using the same method. Can't you just see it?
- Blood supplier seeks donors at Golden Arches
- Background: Fast food outlets & obesity
Researchers in Montreal, Quebec, Canada investigated a novel way to develop a 'universal' red blood cell that involves encasing individual red blood cells within a shell formed from a biocompatible polymer. News items:
- Immunocamouflage system may advance research into blood transfusions that require no typing
- Bloody camouflage: NMR assists 'universal donor blood'
- Mark Scott of CBS explains findings & applications of "immunocamouflage" (NPR)
- Mansouri S, Merhi Y, Winnik FM, Tabrizian M. Investigation of layer-by-layer assembly of polyelectrolytes on fully functional human red blood cells in suspension for attenuated immune response. Biomacromolecules 2011 (Published 9 Feb. 2011)
The polymer hides A, B, and D antigens from their respective antibodies and acts as a chemical cloaking device by masking rbc surface antigens that would otherwise trigger an immune response. The red cells still function because oxygen can penetrate the shell, allowing the rbc to supply oxygen to body tissues and organs. Patients with encapsulated rbc would eventually produce their own red cells to replace camouflaged cells, which would ultimately be broken down and excreted.
The immunocamouflage' mimics a 'find me if you can' scenario seen many times in nature.
SUMMARY
A common thread of these research initiatives is the need for interdisciplinary teams, yet another reason to break down the silos that professionals live in.
All projects are in the early stages, at least 5-10 years from being implemented in the real world. Only time will tell if they go the way of the elusive blood substitute or come to fruition and make transfusion safer.
- Sweet dreams are made of this (Annie Lennox , Hyde Park, London: Live 8, 2005)
