Repoxygen
Encyclopedia
Repoxygen is the tradename for a type of gene therapy
that induces controlled release of erythropoietin
(EPO) in response to low oxygen concentration. It has been developed by Oxford Biomedica to treat anaemia. It has been developed in mice
, is still in preclinical development and has not been extensively tested in humans.
It is constructed as a viral gene delivery vector
carrying the human EPO gene under the control of a so-called "hypoxia control element" (“HRE”). The HRE is claimed to sense low oxygen concentrations and to switch a gene on in response. Repoxygen is designed to be delivered by injection into muscle and therefore to induce syntheses of EPO in the muscle tissue. Normally, EPO is synthesized in the liver
and kidney
s. It leads to increased production of red blood cell
s.
Use of recombinate EPO DNA in mice has shown protective effects for epithelial cells and is being investigated as a prophylatic treatment for lung tissue injury.
Excess EPO, the signalling hormone for more red blood cell production (increased erythrocytes), can lead to erythrocytosis—a condition of too many red blood cells. Erythrocytosis makes the blood thicker and more viscous, making pooling and clotting more likely, and represents an increased stress on the heart (due to the thicker blood). Erythrocytosis is potentially fatal, especially in endurance athletes who are frequently dehydrated during long events.
Repoxygen's delivery vector has triggered immune response in several cases and resulted in at least one confirmed death directly related to the body's immune response to the viral protein delivery vehicle.
Sports without doping tests or regulation hold the most allure for this product. EPO is up-regulated in anoxic environments such as high-altitude climbing; Repoxygen and other gene therapies may find "legal doping" applications in such sports. High-altitude mountain climbing (i.e. attempting to summit Death Zone mountain peaks without supplemental oxygen), or extreme deep diving (requiring ones to hold their breath for several minutes while diving 100+ feet) are but two examples.
Gene therapy
Gene therapy is the insertion, alteration, or removal of genes within an individual's cells and biological tissues to treat disease. It is a technique for correcting defective genes that are responsible for disease development...
that induces controlled release of erythropoietin
Erythropoietin
Erythropoietin, or its alternatives erythropoetin or erthropoyetin or EPO, is a glycoprotein hormone that controls erythropoiesis, or red blood cell production...
(EPO) in response to low oxygen concentration. It has been developed by Oxford Biomedica to treat anaemia. It has been developed in mice
House mouse
The house mouse is a small rodent, a mouse, one of the most numerous species of the genus Mus.As a wild animal the house mouse mainly lives associated with humans, causing damage to crops and stored food....
, is still in preclinical development and has not been extensively tested in humans.
It is constructed as a viral gene delivery vector
Viral vector
Viral vectors are a tool commonly used by molecular biologists to deliver genetic material into cells. This process can be performed inside a living organism or in cell culture . Viruses have evolved specialized molecular mechanisms to efficiently transport their genomes inside the cells they infect...
carrying the human EPO gene under the control of a so-called "hypoxia control element" (“HRE”). The HRE is claimed to sense low oxygen concentrations and to switch a gene on in response. Repoxygen is designed to be delivered by injection into muscle and therefore to induce syntheses of EPO in the muscle tissue. Normally, EPO is synthesized in the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
and kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s. It leads to increased production of red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
s.
Use of recombinate EPO DNA in mice has shown protective effects for epithelial cells and is being investigated as a prophylatic treatment for lung tissue injury.
Excess EPO, the signalling hormone for more red blood cell production (increased erythrocytes), can lead to erythrocytosis—a condition of too many red blood cells. Erythrocytosis makes the blood thicker and more viscous, making pooling and clotting more likely, and represents an increased stress on the heart (due to the thicker blood). Erythrocytosis is potentially fatal, especially in endurance athletes who are frequently dehydrated during long events.
Doping
Athletes could consider using Repoxygen as a means of increasing their number of red blood cells. Due to its alleged self-regulating properties it may be impossible to detect Repoxygen currently. Repoxygen is prohibited both in and out of competition under the World Anti-Doping Code 2006 Prohibited List.Repoxygen's delivery vector has triggered immune response in several cases and resulted in at least one confirmed death directly related to the body's immune response to the viral protein delivery vehicle.
Sports without doping tests or regulation hold the most allure for this product. EPO is up-regulated in anoxic environments such as high-altitude climbing; Repoxygen and other gene therapies may find "legal doping" applications in such sports. High-altitude mountain climbing (i.e. attempting to summit Death Zone mountain peaks without supplemental oxygen), or extreme deep diving (requiring ones to hold their breath for several minutes while diving 100+ feet) are but two examples.
External links
Additional reading
- Yoshimi M, Maeyama T, Yamada M, Hamada N, Fukumoto J, Kawaguchi T, Kuwano K, & Nakanishi Y. (2008). Recombinant human erythropoietin reduces epithelial cell apoptosis and attenuates bleomycin-induced pneumonitis in mice. Respirology 13(5). 639-645.
- Percy MJ. (2008). Familial erythrocytosis arising from a gain-of-function mutation in the HIF2A gene of the oxygen sensing pathway. Ulster Medical Journal 77(2). 86-88.