FAKE BLOOD Ready to Flow.

The rush is on to create artificial blood and save human lives.

On a snowy February morning in 1994, Linda Porter shoveled her driveway in Slatersville, Rhode Island, while her black mutt puppy Sam frolicked in the snow. Shortly after, Linda got a phone call from the local police. Tearing across a street, Sam had been struck by a car. Frantic, Linda rushed to claim her pet, and sped to the Tufts University Small Animal Hospital in Boston.

"Sam was in shock and bleeding internally," says former Tufts veterinarian Robert Murtaugh. The dog's pelvis was shattered. "We didn't know if he'd survive." By the time Sam arrived at the hospital, he'd lost so much blood that he'd become severely anemic, or dangerously short of red blood cells.

Sam badly needed a transfusion, or replacement of fresh blood, to save his life. Transfusions are common for humans, but most vets don't stock dog blood. Only 6 percent of dogs who need transfusions actually get them.

Fortunately, Murtaugh was able to give Sam an experimental artificial-blood substitute, called Oxyglobin. "A day later Sam was trying to stand up and walk around," says Linda. "I was amazed."

Luckily for Sam and his owner, Tufts was helping to test Oxyglobin. In June 1998, the U.S. Food and Drug Administration (FDA) gave Biopure Corporation in Cambridge, Massachusetts, the green light to sell Oxyglobin to all veterinarians in the U.S. It's the first blood substitute ever approved for use. "It's the biggest breakthrough in veterinary medicine in my lifetime," Murtaugh says.

Right now, dogs are the only animals that can legally receive transfusions of artificial blood. But the race is on to inject artificial blood in your veins, too. Half a dozen U.S. biotechnology companies (firms that use organisms to create products) are racing to be the first to produce a human-blood substitute. The winner could save countless lives and corner an estimated $10 billion global market for fake blood.

IS FAKE BETTER?

Artificial blood may be the most anxiously awaited liquid of all time. Why? You don't have to refrigerate manufactured blood (like human blood) to keep it fresh. Fake blood can be stored at room temperature and dispensed in ambulances, rescue helicopters, even on battlefields.

Doctors and nurses can drip the fake stuff into anyone's veins--unlike real blood. Everyone belongs to one of four blood groups (A, B, O, or AB), determined by genes, or hereditary material passed from parents to children. If a doctor injected you with a blood type different from your own, your immune system would attack the blood as a foreign substance and fight it off. The wrong blood would agglutinate, or lump together, to block your blood vessels and arteries--possibly killing you.

With fake blood, the expensive and time-consuming task of matching blood types will be history. The new blood mixes safely with any blood type.

What's more, fake blood is free of HIV, hepatitis, and other harmful viruses that infect the stockpile of donated human blood. No wonder the stakes are so high to get the fake red stuff right.

LIQUID HIGHWAY

What does blood do that's so important? Think of blood as your body's liquid highway. It ferries oxygen and nutrients digested from food to every cell. It carries away waste materials such as carbon dioxide. Blood also helps form disease-fighting cells to attack invading bacteria and viruses.

If you could look inside a single doughnut-shaped red blood cell, you'd see 280 million hemoglobin molecules. Hemoglobin is the protein responsible for absorbing oxygen when the red blood cell passes through the lungs. In mm, hemoglobin releases a constant supply of oxygen to other parts of the body as it floats down the 160,000 kilometers (100,000 miles) of veins inside you.

But the process of exactly how hemoglobin absorbs and releases oxygen has scientists stumped. "Mother Nature has developed the perfect solution to carry oxygen to various parts of your body," says Denis Bourke, a doctor at the Veterans Affairs Center in Baltimore. "I don't think we'll ever beat it, but we may equal it."

BLOOD DROUGHT

Right now, hospitals in many major U.S. cities face a critical shortage of fresh blood. In January 1999, the supply shrank to less than 24 hours' worth, prompting 40 hospitals around the country to postpone non-emergency surgery, like hip and knee replacements.

Considering that every 3.7 seconds an American somewhere receives a transfusion of two to three units (pints) of blood, that's one big blood drought.

What's taking so long to whip up a recipe for fake blood? Scientists have been on the quest for 40 years--a saga mostly of false leads and disappointing test results. "Blood is incredibly tricky stuff to copy," says Douglas Starr, author of Blood: An Epic History of Medicine and Commerce (Knopf, 1998). "But hopes are high. Fake blood may be just around the corner."

FAKE BLOOD: TWO RECIPES

Despite the awesome challenge of manufacturing fake blood, two companies seem headed down the home stretch. The race lost its third major player last year when a company just a year or so away from proclaiming a successful blood substitute halted tests abruptly--after 24 of 52 recipients died. No one knows what triggered the deaths, but doctors suspect the blood substitute caused vessels to constrict lethally.

Now two remaining rival companies are vying to get their "recipes" on the market as soon as possible.

Biopure Corporation, the company responsible for artificial dog blood, is testing a version for humans. Researchers are recycling hemoglobin from slaughtered cows. Sound icky? Hemoglobin is almost chemically identical among all mammals, so that's no problem.

But the researchers face one big challenge: Every hemoglobin molecule in the human body is enclosed by a protective membrane or covering of the red blood cell. Once a hemoglobin molecule is removed from that covering, the hemoglobin tends to break apart into particles called dimers. The particles are toxic and can cause severe damage to the lungs or kidneys.

Biopure's solution is a chemical called glutaraldehyde. The chemical binds, or polymerizes, hemoglobin molecules together, so they don't break apart in the bloodstream. So Biopure's fake blood is actually treated hemoglobin without the red blood cell's protective covering.

MORE OXYGEN FOR THE BUCK

The Biopure recipe may be even more efficient than your own red blood cells at delivering oxygen to body tissues. Because the fake blood molecules are so much smaller than natural red blood cells, "our hemoglobin squeezes into restricted capillaries and around blood clots," says Maria Gawryl, Biopure's vice president of research and development.

But there is one disadvantage: About half of Biopure's hemoglobin is absorbed and digested by the body after just 12 hours, compared to a lifespan of 40 to 60 days for natural red blood cells. So while Biopure's blood doesn't last long in your veins, it should deliver critical short-term oxygen. Meanwhile, your bone marrow churns out 100 million new red blood cells a minute to replace the cells you've lost.

DIFFERENT ROUTE

Researchers at Alliance Pharmaceutical Corporation in San Diego, California, have taken a totally different approach. They've dispensed with hemoglobin altogether. Their recipe, now in final testing: a compound of fluorine and carbon called perfluorocarbons (PFCs). In liquid form, PFCs dissolve more oxygen than any other liquid available.

Alliance hematologists, or blood scientists, claim that PFC particles (0.2 microns in diameter, or 40 times smaller than red blood cells) carry more than twice as much oxygen as hemoglobin and do it twice as fast. How? The PFCs form an emulsion (a mixture of incompatible liquids, like oil and vinegar). The emulsion is a super delivery system because the liquid absorbs oxygen rather than bonding to it as real hemoglobin does. "Think of the emulsion as a liquid sponge," says Alliance vice president Gwen Rosenberg.

If approved for general use, both products can save lives by delivering life-giving oxygen to cells. But neither qualifies as real blood because they lack two key ingredients: white blood cells, to fight infection, and platelets, to help blood clot. Finding a substitute that performs all of blood's vital functions still eludes researchers. The bloody race continues....

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Are Fake Vessels Next

Doctors may soon be able to grow you some new blood vessels. Last year, researchers at Laval University in Quebec, Canada, made the first blood vessels sculpted entirely from human cells. They did it by "growing" dermis (bottom layer of skin) cells in a bioreactor, a device that mimics conditions inside the human body. The cooked-up cells were then rolled into tubes up to I millimeter in diameter (about the size of a pin) and lined with endothelium, cells that coat the inside of blood vessels. Result: "The blood vessel has the look and feel of real tissue," says researcher Nicolas L'Heureux.

Blood vessels made from human cells, magnified 26 times.