Small amounts of carbon monoxide 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 damages the fatty sheaths that protect nerve fibers in the brain and spinal cord.
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.