Toxic substances present in the environment or resulting from the use of medication release chemical compounds which can quickly react with human tissue, thereby causing damage. Up to now, it was not easy to identify this damage at an early stage. Recently, however, toxicologists at Amsterdam Vrije Universiteit have discovered substances formed during this reaction of free radicals with the tissue which are excreted in the urine within only a few days. This discovery has made it easier to determine the damaging effects of chemotherapy in cancer patients, and to do so at an earlier stage. The research was funded by the NWO's Technology Foundation (STW).
The toxicologists carried out tests on rats to see whether the presence of such substances as acetone and aldehydes indicates damage caused by free radicals. These substances are created when free radicals react with lipids in the membranes of cells. The body thinks they are waste products and excretes them in the urine. The rats received doses of toxic chemicals which led to free radicals being released in the kidneys or the liver. Higher doses of these toxic chemicals mean increased excretion of acetone and aldehydes. The concentrations of these substances in the urine give an earlier indication of the damage caused by the free radicals than can be done using other techniques.
The toxicologists then examined whether acetone or aldehydes can also be used as indicators of physical damage in patients receiving chemotherapy for cancer. Chemotherapy makes use of a variety of substances including cytostatics, which may result in the production of free radicals in the body. Depending on the type of chemotherapy, the amount of acetone and aldehydes excreted during the first three days after treatment was between two and twelve times higher than normal. By administering anti-oxidants, it was possible to restrict excretion of these products. Anti-oxidants react with the free radicals, making them harmless to the body.
Doctors believe that arteriosclerosis, cancer, Alzheimer's disease and chronic infections are related to damage by free radicals, but whether these are the cause or the result is as yet unclear.
Further information:
Professor Vermeulen
31-20-444-7590, Fax: 31-20-444-7610
vermeule@chem.vu.nl