Iron and Erythropoietin

1
Iron and Erythropoietin

• Chapter 9

2
Overview

• EPO basics
• EPO effects on exercisers
• EPO effects on performance
• Risks/potential complications

3
EPO Basics

• Erythropoietin (EPO)
• Naturally occurring hormone which triggers RBC
  production
• Hemantinic agent
• Increases both of RBCs and amount of hemoglobin
  in them
• Epoetin alfa
• Bioengineered synthetic EPO

4
EPO Basics

• Commonly abused, particularly among cyclists and
  other endurance athletes
• Developed after discovery of blood doping
• Approved for human use in treating anemia in
  patients w/ kidney disease

5
EPO Basics

• Utilization may be justifiable in some, but not
  without concurrent renal failure
• Sports anemia
• Footstrike hemolysis
• Blood in stool after vigorous activity

6
EPO Basics

• Despite widespread utilization, very little is
  known about the impact of EPO on acute aerobic
  performance in healthy subjects
• Even less is known about long-term, systemic
  influence of prolonged use

7
EPO Basics

• Hematocrit
• Percentage of blood occupied by RBC
• EPO increases hematocrit by increasing number,
  not size of RBCs

8
EpO Effects on Exercisers
9
EpO Effects on Exercisers

• EPO abuse can increase hematocrit ( RBC in
  blood measures the O2-carrying capacity of
  blood)
• Test was basis for disqualification of cyclists
  from a 1998 international race
• Hematocrit not ideal to test for VO2-max effects
• Hemoglobin is the actual O2-carrying molecule
• Limited data
• Some show increased Hb content after EPO use
• Difficult to relate to performance effects

10
EpO Effects on Exercisers

• EPO decreases exercise HR in diseased subjects,
  normal subjects, and normal exercising subjects
• Decreases post-exercise lactate levels in
  diseased subjects

11
Effects on Performance

• Improves performance in anemic dialysis patients
• Aerobic capacity
• Muscular strength/endurance
• Elite athletes
• VO2 increased by 8 time to reach exhaustion
  delayed by 17
• Little scientific data has been generated,
  although EPO has been commercially available
  since 1989

12
Potential Complications

• Significant increase in SBP
• Increased blood viscosity
• Could lead to seizures or thrombosis
• Possible to start a race at 50 hematocrit and
  end it at 60, potentially very dangerous
• Anabolic steroids can potentiate effects of EPO

13
Banned Status

• Epoetin alfa banned by NCAA, USOC, IOC, as is
  blood doping with autologous reinfusion of RBC
• Abuse is difficult to detect, since it is rapidly
  cleared from bloodstream
• Hematocrit dependent on other factors, such as
  changes in plasma volume, and RBC size