Antibiotics destroy mitochondria
Antibiotics have saved a huge number of lives of patients with bacterial infections, but these valuable drugs also have a dark side. Like most medicines, many antibiotics can have undesirable side effects, which is manifested by more or less severe symptoms.
Not an exception are the drugs of the fluoroquinolone class, the most popular of which is known as ciprofloxacin. Fluoroquinolones are among the most widely used broad-spectrum antibiotics and are usually prescribed for the treatment of infections of the respiratory organs, ear and genitourinary tract. While drugs of this class are generally well tolerated by patients, in some people they cause serious health problems, including tendon ruptures, irreversible nerve damage or depression. The reasons for the development of these pathologies are currently unclear.
Researchers at the University of Eastern Finland have studied the effect of ciprofloxacin on mitochondria – important cellular organelles that produce energy for the needs of the cell. Mitochondria have their own genome in the form of a circular DNA chain, to maintain the integrity of which topoisomerase enzymes are necessary. These enzymes regulate DNA topology by untangling knots and twisted fragments of the genome, cutting and reconnecting the DNA chain. The mechanism of action of fluoroquinolones is the inhibition of a bacterial enzyme of the topoisomerase family – DNA gyrase - which leads to the death of bacteria. However, a side effect of the action in this case is the inhibition of topoisomerase-2 of human cells.
The authors found that topoisomerase-2 is particularly important for mitochondrial genome replication, as it regulates the twisting of this small DNA molecule during transcription. Ciprofloxacin interferes with the normal course of this process by changing the topology of mitochondrial DNA. This disrupts the synthesis of energy in the mitochondria and blocks the processes of cell growth and differentiation. Most likely, it is this disastrous effect on mitochondria that is the cause of the adverse events experienced by patients, and the reason why fluoroquinolone drugs should be prescribed with great caution.
Article by Anu Hangas et al. Ciprofloxacin impairs mitochondrial DNA replication initiation through inhibition of Topoisomerase 2 is published in the journal Nuclear Acids Research.
Evgenia Ryabtseva, portal "Eternal Youth" http://vechnayamolodost.ru according to the University of Eastern Finland: Ciprofloxacin has dramatic effects on the mitochondrial genome — antibiotics should be used cautiously.