The administration of iodine after a heart attack can significantly reduce damage to the heart muscle, reports New Scientist.
A heart attack is caused by blockage of the coronary vessels which carry blood to the heart muscle. This can be the cause of death, but the greatest damage paradoxically occurs when the vessels are restored, when oxygen-rich blood enters the tissues. Cells adapt their metabolism to an oxygen-poor environment, which, if it is suddenly available, leads to damage. For reasons not fully understood, the re-inflow of blood (reperfusion) causes the intensity of metabolism and oxygen consumption by heart cells to increase to a level several times higher than under normal conditions. The resulting abnormal compounds cause the cells to be attacked by the immune system and destroyed. If many cells are damaged, the heart may stop beating.
Mark Roth of the Fred Hutchinson Cancer Research Center in Seattle caused heart attacks in mice by ligating their vessels. Five minutes before removing the ligature and opening the vessel, he administered an injection of iodine compound or – for the control group – saline, i.e. 0,9 percent. NaCl. As a later section showed, the hearts of mice given iodine were damaged by 75 percent. Roth believes that iodine may inhibit the production or secretion of metabolism-stimulating hormones by the thyroid gland. Post-infarction clinical trials of iodine should begin within a year or two.
However, as Malcolm Bell of the Mayo Clinic College of Medicine in Rochester (Minnesota) warns, specialists have been working on the problem of reperfusion for years. Many treatments that have shown promising results in animals have not worked well in humans.
Graham Nichol of the University of Washington in Seattle admits that most of the measures taken to prevent the effects of reperfusion so far have failed in humans, but is impressed with the results obtained by Roth. In his opinion, the chances of success are increased by the fact that iodine acts in multiple ways, not just by one specific mechanism. 75% reducing tissue damage would improve heart function, so survivors of a heart attack would be less likely to experience problems in the future – including death from heart failure. Many sick people could be saved.
It is not known whether taking iodine tablets daily would prevent a heart attack, but Roth says it is unlikely – the body would probably get used to constantly elevated levels of this element. It does not rule out, however, that taking iodine before bypass surgery could be beneficial and should be investigated. (PAP)