Drug Reduces Deaths from Bleeding

A drug that prevents blood clots from breaking down has recently been shown to reduce deaths from uncontrolled bleeding following traumatic injury. In a study of over 20,000 patients, the drug (tranexamic acid, or TXA), reduced deaths due to bleeding after traumatic injury by 15%.

TXA has been used by doctors for some time. Surgeons sometimes administer it before surgery to prevent bleeding in surgical patients, and it has been prescribed for women with particularly heavy menstrual periods to prevent excessive blood loss during menstruation. But this is the first real evidence that the drug is also effective when given to patients after traumatic injury with blood loss. The drug seems to have no significant negative side effects.

Over three million people a year die of traumatic injury. Blood loss is usually a major factor in the patient’s death. This drug might save a lot of lives if it were available everywhere on short notice.

Beating the EPO Blood Doping Test

Synthetic erythropoietin, called EPO, was widely used by endurance athletes in the 1990s to boost red blood cell production and blood oxygen carrying capacity. The use of EPO declined after 2000 when the World Anti-Doping Agency (WADA) developed a test to detect EPO in urine.

But now, WADA believes that athletes could be beating the current EPO urine tests by “microdosing” – injecting very small (micro) doses of EPO at night. EPO is excreted so rapidly into the urine that most of an injected dose will be eliminated from the body within eight hours. Thus, microdosing is likely to go undetected as long as urine samples are not demanded in the middle of the night.

Microdosing works because the effects of the erythropoietin outlast the hormone itself. Researchers now know that even such small, intermittent doses of EPO will boost the body’s production of red blood cells significantly over time. They aren’t publishing their dosage information to avoid providing a recipe for blood-doping, but they suspect that athletes already know.

The Spleen Stores Monocytes

Shortly after severe tissue damage such as that caused by a heart attack or an infection, the number of monocytes, the white blood cells that eventually mature into macrophages, increases dramatically in the blood. These new monocytes appear too quickly to have been newly produced from stem cells in bone marrow. So where do they come from?

Apparently they come from the spleen. The spleen stores up to ten times as many monocytes as there are in the bloodstream at any one time. When a tissue is injured the spleen releases its stored monocytes, which then migrate to the site of injury, develop into macrophages, and participate in the cleanup and repair process. It’s a pretty efficient use of resources, when you think about it - a virtual army of monocytes is kept on standby, ready to be deployed when needed.

Cleansing Blood With Magnets

Researchers at Harvard University are working on an innovative method for treating blood infections - drawing the bacteria out of blood with magnets. They mix infected blood with tiny antibody-coated magnetic spheres only 1/8 the size of red blood cells. The antibodies on the spheres attach to bacteria in the blood, and then the spheres and the bacteria are drawn off together using a powerful magnetic field.

In initial experiments the method removed up to 80% of the bacteria in small samples (10-20 ml) of blood. However, several questions remain to be unanswered: 1) Can the method be tooled up to cleanse the larger volume of blood in human patients? 2) Will reducing the bacterial or fungal load in a patient’s blood actually improve the patient’s recovery? 3) What might happen to the patient if a few magnetic beads are not removed from the blood before it is returned to the patient?

It may be several years before we know if the method can be used safely and effectively to treat blood infections in human patients.

PRP Therapy for Connective Tissue Injuries

If you’ve ever injured a tendon or ligament you know how painful such injuries can be. You also know that injured connective tissue takes longer to heal than injured muscle tissue. That’s because there is generally very little blood flow to connective tissue, especially in areas in and around fluid-filled joints. As a result, very few blood platelets and white blood cells are delivered to the area to help with tissue repair.

Experts in sports medicine now think they have a potential solution. It’s called “platelet-rich plasma therapy”, or PRP for short. The method is surprisingly straightforward. A sample of the patient’s own blood is enriched in platelets by removal of the blood cells and most of the water and electrolytes. The remaining platelet-enriched plasma is then injected directly into the injured joint or connective tissue. The theory is that the platelets will release proteins involved in tissue repair and attract other tissue-repair cells to the area, speeding the healing process.

Does PRP therapy work for such common connective tissue injuries as rotator cuff strains, Achilles tendon injuries, and tennis elbow? Clinical trials are underway in several countries, including the U.S., to find out. Meanwhile, some professional athletes have already tried it, including Los Angeles Dodgers’ baseball pitcher Takashi Saito and Pittsburgh Steelers’ receiver Hines Ward. Ward has his answer already; he was able to play in the Superbowl just two weeks after a knee injury that generally sidelines players for 4-6 weeks.

FDA Approves a Genetically Engineered Drug

The first human drug produced by livestock genetically engineered to contain a human gene has now been approved by the Food and Drug Administration. A company called GTC Biotherapeutics developed a herd of goats (Figure 20.10 of Human Biology) that contain the human gene for antithrombin III, a protein used to prevent blood clots in people with hereditary antithrombin deficiency. One advantage of using farm animals is that larger quantities of human proteins can be obtained from the milk of genetically engineered animals than from human blood. One of GTC’s goats, for example, can produce as much antithrombin/year as the amount that can be extracted from 10,000 gallons of human blood!

How did GTC manage to get the antithrombin to be produced in milk, so they could harvest the protein by milking the goats instead of bleeding them? Simple concept, really - they linked the human gene for antithrombin to a goat gene for a milk protein.

Storing Umbilical Cord Blood

An article entitled “When Medicine Meets Marketing" (Newsweek Dec. 22, 2008, pp. 49-51) would be a good supplementary reading for when you cover the topic of blood in your human biology college course. The article describes how private blood storage companies are waging a fierce marketing campaign designed to convince young parents to bank their baby’s cord blood (for a hefty fee), just in case the stem cells in cord blood might be useful in the future. The scientific background for understanding the article is covered in Human Biology 5th ed., pp.154-155.

Based on what you have learned from the textbook and/or from the Newsweek article, are you more likely to; a) bank your baby's cord blood privately, b) donate your baby's cord blood to a public cord blood bank registry, or c) do neither? On what do you base your choice?