Good poison? Carbon monoxide may stifle multiple sclerosis.
Small amounts of carbon monoxide carbon monoxide, chemical compound, CO, a colorless, odorless, tasteless, extremely poisonous gas that is less dense than air under ordinary conditions. It is very slightly soluble in water and burns in air with a characteristic blue flame, producing carbon dioxide; might alleviate symptoms of multiple sclerosis, a study in mice suggests. The finding may offer a treatment for MS, which strikes when a person's immune system immune system
Cells, cell products, organs, and structures of the body involved in the detection and destruction of foreign invaders, such as bacteria, viruses, and cancer cells. Immunity is based on the system's ability to launch a defense against such invaders. damages the fatty sheaths that protect nerve fibers in the brain and spinal cord spinal cord, the part of the nervous system occupying the hollow interior (vertebral canal) of the series of vertebrae that form the spinal column, technically known as the vertebral column. .
At first glance, the approach seems fraught with problems. Carbon monoxide inhalation can be lethal. But the body makes the molecule naturally in small amounts when an enzyme called heme-oxygenase-1 (HO-1) breaks down a portion of the blood protein hemoglobin.
That enzyme might act as a brake to prevent inflammation from getting out of hand, says immunologist Miguel P. Soares of the Gulbenkian Institute of Science in Oeiras, Portugal. Previous studies showed that HO-1 is activated in the presence of inflammatory immune system cells and that carbon monoxide slows inflammation.
In patients with MS, inflammatory cells strip away myelin sheaths, and the subsequent nerve damage results in fatigue, poor balance, and loss of muscle control.
To find out whether the anti-inflammatory effect generated by HO-1 could limit myelin myelin /my·elin/ (mi´e-lin) the lipid-rich substance of the cell membrane of Schwann cells that coils to form the myelin sheath surrounding the axon of myelinated nerve fibers. damage in the brain and spinal cord, Soares and his team tested mice that had a disease similar to MS. Animals receiving a drug that revs up HO-1 production showed far less myelin damage than did the other mice. Among mice paralyzed par·a·lyze
tr.v. par·a·lyzed, par·a·lyz·ing, par·a·lyz·es
1. To affect with paralysis; cause to be paralytic.
2. To make unable to move or act: paralyzed by fear. by the disease, most of those receiving the drug recovered movement. Mice given inert treatments failed to improve.
Furthermore, a group of mice with boosted HO-1 activity and another group that directly inhaled carbon monoxide had substantially fewer inflammation-causing immune T cells T cells
A type of white blood cell produced in the thymus gland. T cells are an important part of the immune system. Infants born with an underdeveloped or absent thymus do not have a normal level of T cells in their blood. in their brains than did mice getting a placebo. The researchers report their findings in the February Journal of Clinical Investigation The Journal of Clinical Investigation (JCI or J Clin Invest) is a leading biomedical journal, which is radically different from many of its peers in having a high impact factor (in 2006, 15.754) and offering all its contents entirely free. .
The study also showed that boosting HO-1 activity reduces the accumulation of inflammatory T cells on myelin sheaths. Further tests indicated that HO-1 and carbon monoxide keep other immune cells from activating the myelin-targeting T cells.
MS patients often have periods of remission, followed by a recurrence of symptoms. "These relapses probably occur because of a lack of sustained HO-1 [production], Soares says.
However, neuropathologist Cedric S. Raine of the Albert Einstein College of Medicine
The Albert Einstein College of Medicine (AECOM) is a graduate school of Yeshiva University. It is a private medical school located in the Jack and Pearl Resnick Campus of Yeshiva University in the Morris Park in New York City New York City: see New York, city.
New York City
City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. says that the new study, while extensive, falls short of establishing a clear link between carbon monoxide and a dampened immune response. For example, he says, carbon monoxide toxicity might simply cause stress and induce the release of steroids, which suppress inflammation.
Meanwhile, research on carbon monoxide treatment "has become a very hot Soares says. Other studies of laboratory animals suggest that carbon monoxide eases inflammation in intestines, lungs, and blood vessels (SN: 2/22/03, p. 126). Last year, U.S. scientists began recruiting participants for a study to gauge the effects of small doses of inhaled carbon monoxide on lung inflammation. But the best delivery method might be carbon monoxide-releasing drugs, which could be targeted to specific tissues, Soares says.