Probing the hotdog’s secret
Preservative may be good medicine Researchers in ‘full court press’
Could the salt that preserves hotdogs also preserve your health?
Scientists at the U. S. National Institutes of Health think so. They’ve begun infusing sodium nitrite into volunteers in hopes it could prove a cheap but potent treatment for sickle cell anemia, heart attacks, brain aneurysms, even an illness that suffocates babies. Those ailments have something in common: they hinge on problems with low oxygen, problems the U. S. government’s research suggests nitrite can ease. Beyond repairing the reputation of this often maligned meat preservative, the work promises to rewrite scientific dogma about how blood flows and how the body tries to protect itself when that flow is blocked. Indeed, nitrite seems to guard tissues — in the heart, the lungs, the brain — against cellular death when they become starved of oxygen.
It doesn’t mean artery-clogging hot dogs are healthy. But the NIH researchers have filed for patents on this old, overlooked chemical and are hunting a major pharmaceutical company to help develop it as a therapy — even as doctors await the enrolment of sick patients into research studies in coming months. The scientists are so convinced of nitrite’s promise that lead researcher Dr. Mark Gladwin says the government will pursue drug development on its own if necessary.
“ We think we stumbled into an innate protection mechanism,” he says.
Dr. Christian Hunter of California’s Loma Linda University hopes by January to begin studies of nitrite treatment for babies with an often fatal disease called pulmonary hypertension. If the drug works, he says, it will be easy and inexpensive to use.
Gladwin and an NIH cardiologist, Dr. Richard Cannon III, discovered nitrite’s effect by accident while studying a related compound, nitric oxide, long known to improve blood flow by dilating blood vessels, but difficult to use as a drug.
Gladwin and Cannon injected sodium nitrite into healthy volunteers. Tiny doses almost tripled blood flow. Moreover, when people exercised, nitrite levels plummeted in the muscles being worked — the body was using it. The researchers were stunned. For 100 years, scientists thought nitrite had little medical relevance. High doses are an antidote for cyanide poisoning, but they’re also toxic. In 1944, 11 New Yorkers literally turned blue, their blood struggling for oxygen, after they accidentally ate the meat preservative instead of table salt. The low levels that naturally occur in the human body were thought to be inert, unimportant. Not anymore. “ This has led to an avalanche of work,” says Gladwin, who this week hosts an NIH meeting where scientists will compare nitrite research. The work done so far is “ sufficiently encouraging to warrant a full-court press,” says Dr. Franklin Bunn, a Harvard Medical School professor. When oxygen levels drop, the body’s natural stores of nitrite convert to nitric oxide, in turn dilating vessels so more blood — and more oxygen — gets through. Nitrite also seems to help preserve tissue — in the case of heart attacks, for example — by interrupting the chain reaction caused when harmful proteins spewed by dying cells in turn take out their neighbours. The first human patients to test nitrite have sickle cell disease; another piece of the nitrite puzzle is its connection to hemoglobin, the oxygen- carrying protein that makes blood red.
Doctors have long thought the bouts of crippling pain suffered by sickle cell patients resulted when their abnormally shaped red blood cells clumped together to block blood flow. But Gladwin found the patients’ blood vessels were constricted by an absence of nitric oxide — causing more pain as sickle- shaped blood cells push through.
At NIH’s hospital in Bethesda, Md., Gladwin has infused nitrite into six sickle- cell patients. This first- stage study is designed to test safety, not nitrite’s effect on pain, but it is dilating participants’ blood vessels, he says.