Artificial Blood

Nov. 7, 2014

By Medical Discovery News

Red blood cells

In the series “True Blood,” the invention of artificial blood allows vampires to live among humans without inciting fear. In the real world, however, artificial blood would have very different effects, as 85 million units of blood are donated worldwide and there is always a demand for more. An artificial blood substitute free of infectious agents that could be stored at room temperature and used on anyone regardless of blood type would be revolutionary.

That is exactly what a group of scientists at the University of Essex in England are working on, although the search for an artificial blood substitute started 80 years ago. All red blood cells contain a molecule called hemoglobin, which acquires oxygen from the lungs and distributes it to cells throughout the body. Their plan is to make an artificial hemoglobin-based oxygen carrier (HBOC) that could be used in place of blood.

HBOCs are created using hemoglobin molecules derived from a variety of sources, including expired human blood, human placentas, cow blood, and genetically engineered bacteria. The problem is that free hemoglobin, which exists outside the protective environment of red blood cells, breaks down quickly and is quite toxic. Therefore, HBOCs are not approved for use in most of the world due to their ineffectiveness and toxicity.

The active group in hemoglobin that binds to oxygen is called heme, which can actually be quite toxic. Scientists have found a variety of ways to modify hemoglobin to increase its stability but safety issues still remain. If the hemoglobin’s processing system is overwhelmed, a person may develop jaundice, which causes the skin and whites of the eyes to turn yellow. Too much free hemoglobin can also cause serious liver and kidney damage. When free hemoglobins, not whole red blood cells, are infused, the human body’s natural system for dealing and disposing of this molecule is overwhelmed, leading to toxicity. That is why blood substitutes consisting of free hemoglobin have been plagued with problems, such as an increase in deaths and heart attacks.

But scientists involved in this latest effort to produce a blood substitute have been reengineering the hemoglobin molecule. They are introducing specific amino acids, which are the building blocks of proteins, into hemoglobin in an effort to detoxify it. Preliminary results indicate that this approach may work. They have already created some hemoglobin molecules that are much less reactive and are predicted to be less toxic when used in animals or people.

If successful, this HBOC would be a universal product, meaning it could be used on everyone and there would be no need to waste time on testing for blood types. It would also be sterile, free of any of the infectious agents that donated blood must be tested for. Instead of refrigeration, it could have a long shelf life at room temperature, perhaps years, so it could be stockpiled in case of major emergencies. It could even be kept on board ambulances and at remote locations far from hospitals. The search for an effective and nontoxic blood substitute is one the medical field’s Holy Grails, and if proven successful, these scientists may have finally found it.

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Knocking Out Hepatitis C

March 7, 2014

By Medical Discovery News

Hepatitis C

Good news awaits Hepatitis C patients. In the next few years, new drugs that specifically target the Hepatitis C virus, curing a person more quickly without the severe side effects, will become available. Some physicians and patients are even opting to wait for these new drugs rather than endure the current therapy.

Today, this viral infection is most often acquired by drug users sharing needles. The Hepatitis C virus can cause a mild illness lasting a few weeks but in some people it can cause a serious lifelong illness. One major problem is that many people are unaware that they are infected until they have symptoms of liver damage. It is the leading cause of cirrhosis and liver cancer and the most common reason for liver transplantation in the United States.

An estimated three to four million Americans are infected, and deaths from Hepatitis C are expected to rise in the future as those unaware of their infections begin to have symptoms. There is no vaccine and the current drug regimens can cure about 70 percent of infected people but the serious side effects include anemia, insomnia, depression, fever, and severe rashes.

Hepatitis C is most commonly treated with a combination of interferon and ribavirin for 24 to 48 weeks. However, because of their side effects and the fact that the drugs do not work for everyone, drug companies have been working hard to develop new treatments.

These new drugs are predicted to wipe out Hepatitis C infections with one pill per day for as little as eight weeks, without severe side effects. The only downside is their predicted costs range from $60,000 to more than $100,000 for a course of treatment. The new drugs, much like those that are used to treat HIV infection, target enzymes the Hepatitis C virus requires to reproduce.  However, the Hepatitis C virus does not make its genetic information a permanent part of a cell’s genome like HIV does, so it can be eliminated, therefore curing the person. If the virus is eliminated the liver can heal itself to some extent, but people cured of Hepatitis C may still be at higher risk for liver cancer.

One of these new drugs, called sofosbuvir by Gilead Sciences, inhibits the enzyme that copies the virus’s genetic information, therefore blocking virus reproduction. The effectiveness of the drug depends on the type of Hepatitis virus. The majority of Hepatitis C patients in the U.S. would require the addition of interferon for 12 weeks. Gilead has a second drug nearly ready called ledipasvir, which in combination with ribavirin could eliminate the need for interferon, the source of the worst of the side effects of current treatments.

Several other companies are racing to introduce additional medications to treat Hepatitis C. Having tolerable therapies available will encourage people to get tested and treated earlier for Hepatitis C, before liver damage begins. This is a huge benefit to public health that will substantially reduce the need for liver transplants and the number of deaths from liver failure and liver cancer.

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