There's an interesting article up at Science about developments in the search for a good blood substitute. It starts with this bit of history that I think is new to me:
In 19th century New York City, Theodore Gaillard Thomas enjoyed an unusual level of fame for a gynecologist. The reason, oddly enough, was milk. Between 1873 and 1880, the daring idea of transfusing milk into the body as a substitute for blood was being tested across the United States. Thomas was the most outspoken advocate of the practice.
At the time, severe bleeding was often a death sentence. Blood transfusion was practiced, but it was something of a crapshoot. Medical science was still 3 decades removed from discovering blood types. Patients who received mismatched blood suffered discolored urine, itching, and a sometimes-fatal complication: hemolytic shock, wherein their own immune systems attacked the transfused cells.
Doctors in the U.S. were looking for something less risky to stabilize a hemorrhaging patient. Thomas was sure milk was the answer. In 1875, he injected 175 milliliters of cow’s milk into a woman suffering from severe uterine bleeding after an operation to remove her cancerous ovaries. At first, he wrote, the patient “complained that her head felt like bursting.” She soon developed a high fever and an abnormally high heart rate, but recovered a week later. Thomas subsequently performed seven separate milk transfusions, publishing his results in several medical journals, and predicted their “brilliant and useful future.”
It was not to be: Saline solutions, still used today, were introduced the next decade as a much less dangerous, if imperfect, stopgap measure for emergency bleeding.
Gosh. They really did try any old idea in the hope it might work.
Anyway, the other curious thing in the article is that a new experimental blood substitute has been developed by a doctor with the surname "Doctor". Here's the reason why it could be useful:
Doctor is as fervent an advocate for hemoglobin-based oxygen carriers (HBOCs), as ErythroMer and its predecessors are more formally known, as Thomas was for lacteal transfusions. Donated blood has a shelf life of just 42 days. There’s also not enough, even in developed countries with well-organized blood donation systems: In January 2022, the American Red Cross, which distributes 40% of the country’s donor blood, declared the first-ever national blood crisis, as its supply—especially precious O-negative blood, the universal type—dipped dangerously low. Meanwhile, hemorrhagic shock caused by severe blood loss kills some 20,000 people in the U.S., and 2 million globally, every year.
An artificial “blood” could, perhaps, fill the void. In settings where fresh blood is hard to come by, such as battlefields and rural areas (where ambulance wait times are sometimes as high as 45 minutes), ErythroMer could be given on the fly to maintain the vital flow of oxygen to organs until someone reaches a hospital. It’s a freeze-dried powder that remains usable for years and can be reconstituted by simply mixing it with widely available saline. And ErythroMer should be safe for any blood type, because its membrane doesn’t include the red blood cell surface proteins that cause mismatches.
....
So far Doctor’s creation remains in animal testing, but it isn’t the only effort to package hemoglobin inside lipids to fashion a viable blood substitute. A rival product in Japan has already been tested in a few people and generally appears safe.
But the success of these new products is far from guaranteed. Barely 2 decades ago, earlier formulations of HBOCs were scuttled or sidelined after trial participants died. Subsequent attempts haven’t fared much better. The most advanced HBOC to date, approved for people in South Africa and Russia, has struggled amid concerns about side effects.
All very interesting...
No comments:
Post a Comment