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Originally Posted by CosmicWon
This is an interesting discussion and while I stand more often than not with Halsey on most issues, I'd rather expand my knowledge of horsemanship than be obstinate in the face of science and thus wanted to seek more information on the effect of EPO in equine athletes in order to form a more confident position.
Long story short, much of the scientific research I found failed to reject the hypothesis that EPO has little to no positive effects on performance horses. In fact, I found numerous citations stating EPO "therapy" would have a detrimental effect on equine performance due to the splenic reaction that occurs naturally in horses during strenuous work.
While at rest, yes, it was found EPO does increase red blood cells and aid oxygenation in horses, and I assume this is the physiological reaction mimicked when we send weak foals and horses convalescing from rehab or open wounds to the hyperbaric chamber.
More importantly for our discussion, though, the opposite was found to be true when horses in regular exercise regimes where given EPO therapy: The blood was oxygenated to the point where circulation became too thick/viscous and therefore restricted blood flow to the point whereby it negatively affected the racing efforts of the horses in the study group.
And interestingly enough, the FEI which governs horsesports Worldwide and maintains a no-tolerance stance towards drugs recently suspended two endurance riders and horses when their mounts tested positive for EPO. The FEI spokeman explained the rationale was not centered on PEDs but rather that EPO in general are banned from sports worldwide.
The spokesman likewise cited the same scientific findings that EPO is not a performance enhancer in horses but rather a performance inhibitor due to the constricting physiologic response on circulation as a result of too many red blood cells in their system.
Citations: http://www.thehorse.com/articles/376...-for-human-epo and http://veterinarynews.dvm360.com/vet...ID=1&sk=&date=
Not sure if those findings will change any minds in those who "want to believe" but it helped me clarify where I stand and why. |
Did you actually read this article?
Here are some key passages
"We showed that rHuEPO causes an increase in red cell mass, hematocrit and aerobic capacity," McKeever says. "But at the same time, we also saw an increase in blood viscosity, measured at different shear rates representative of different points in the cardiovascular system (i.e. aorta versus capillaries).
The take-home message was that the recombinant human EPO worked in horses, as suspected. But our splenectomized study horses did not represent the intact racehorse."
McKeever, now at Rutgers Equine Science Center, did a followup study in standardbreds with intact spleens, following a similar protocol but with a higher dose of rHuEPO (50 IU/kg given three times a week for three weeks). The purpose: to show that rHuEPO increased red cell volume and aerobic capacity in an intact standardbred horse. But they also tried to detect antibodies to the compound.
"It was common for a certain number of horses to show a cross-reactivity problem, as if the horse was responding to a foreign protein," McKeever says. "After three injections of rHuEPO, the horses did show evidence of antibody production."
They also showed that the erythropoietin molecules were similar in humans and horses, that the erythropoietin is excreted fairly rapidly and that the red cells that develop stay in the system for quite a long time, as do the antibodies. (The antibody titer can therefore be used to detect rHuEPO, requiring horses to register a specific low level before they can race.)
"The horse has some protective mechanisms, but when we did our studies, we had a cutoff point for administering the rHuEPO," states McKeever. "We were worried about getting the blood too thick."
Thickening the blood could result in clotting, a reduction in cardiac output and the ability to transport oxygen since the horse is naturally losing fluids at exercise. Add the diuretic furosemide, which is commonly administered in racing horses, and you may exacerbate the problems.
"Not only do you have the cross-reactivity problem, but if the blood becomes too viscous, and you don't know where that occurs in the horse, you could potentially run into sludging problems—microvascular problems that could disrupt the function of very small vessels," McKeever says. "That is what they purportedly see in humans. With the thickening of fluid within small vessels and an increase in red blood cells, one may begin to develop blood clots. Then add the use of furosemide or aminocaproic acid, and you're asking for a disaster."
Despite rHuEPO's purported benefit, the horse's physiology remains extremely sensitive, fighting to maintain blood pressure, blood volume and blood tonicity.
"When we administered rHuEPO (as in some human studies), producing a short-term increase in red cell mass and blood volume, the body sensed that via its baroreceptors and signaled to get rid of some of that extra blood volume," McKeever says. "We actually saw a decrease in plasma volume. Therefore, although you've increased the red cell mass, you've maintained overall blood volume at the expense of plasma volume. This could have implications for normal regulation, since you no longer have the pool of water for sweat production."
It states that EPO does increase the amount of Red Blood cells but the danger is self-regulation with the horse's own body decreases the plasma volume to avoid the blood being too thick.
This is why when you administer EPO to horses you need to also use an anti coagulant like Warfarin to counter this natural effect.
One of the biggest reasons the California horse deaths investigation was BS was because many of the dead horses had Warfarin present and it was passed off that they got contaminated because of backstretch Rat control. Warfarin is also used in Rat poison as an effective way to kill rats.
As soon as you see a horse on an anti coagulant you are pretty guaranteed to see them also on EPO
