Rare side effects of prescription drugs have always been annoyingly
and rapidly advertised at the end of media commercials. Even prescribed
antibiotics give the warning labels of such effects but never did I think these
side effects occurred at the molecular level! Recently, I came across an article from the Wyss Institute for Biological Inspired Engineering at Harvard
University where two methods to avert the harmful side effects of long-term
antibiotic treatment were discussed after biochemical tests confirmed the
damage antibodies cause to human cells.
Antibiotics cause oxidative stress in cells, which leads to cellular damage. For example, in healthy cells (left), mitochondria, which are labeled yellow here, are long and highly branched. But in cells treated with the antibiotic ciprofloxacin (right), mitochondria are abnormally short and unbranched, and they do not function as well. Image credit: Sameer Kalghatgi and Catherine S. Spina [1].
Doctors usually prescribe antibiotics with the false
impression that it will kill bacteria and leave the human cells and tissues unharmed.
However, over the years continual occurrences of people experiencing these commonly
warned side effects led scientists to analyze the underlying factor of such
effects. A group of scientists led by Jim Collins from the Wyss Institute had
already determined that antibiotics kill by bacteria by a process called
oxidative stress. This is “a condition in which cells reproduce chemically
reactive oxygen molecules that damage the bacteria’s DNA and enzymes, as well
as the membrane that encloses the cell [1].” However, after several biochemical tests,
this oxidative stress was found to damage the DNA, proteins, lipids and
mitochondrial functionality in human cultured cells after pro-longed use of
antibiotics. Clinically, this gives a desperate call for a way to counteract
the effects of oxidative stress but this team of scientists has found it! The
scientists suggest that using an antibiotic that stops the reproduction of
bacteria will reduce the need for a huge amount of reactive oxygen production
therefore lessening the effects of oxidative stress. Also, they indicate that
using antioxidants would be a good way to flush out already produced reactive oxygen.
Since the two methods they have indicated include FDA-approved reagents this
solution is eagerly awaiting clinical use.
Do you believe more trials other than the ones mentioned in
this article need to be produced in order to analyze the effectiveness of the
suggested solution before putting it out in the clinical market? I think that because the pharmaceutical
industry hasn't done enough to do away with all the common health side effects
of antibiotics and/or medicines, this method of reducing oxidative stress
should be put to use immediately. However, I ponder if after all the
mitochondrial damage has occurred, there are effective methods of retroactively
alleviating the damage. I would love to hear your thoughts about this topic!
Here's is the link to the article:
[1] Dodging antibiotic side effects. Ferber, Dan. Wyss Institute for Biologically Inspired Engineering at Harvard University. July3, 2013. http://wyss.harvard.edu/
I remember learning in school about oxidative damage as a byproduct of our immune response during phagocytosis. The neutrophils and monocytes would undergo an oxidative burst. This sudden gigantic uptake of oxygen results in the formation of a superoxide free radical that then is used to make toxic substances to kill bacteria. Antioxidants are helpful to mitigate damage from the radicals. I did not know that antibiotics could create oxidative stress as well.
ReplyDeleteThis is the first time I hear about oxidative stress triggered by antibiotics. But most serious and common side effects are usually hypersensitivity reactions and the destruction of the normal gastrointestinal microbial flora. For example, vancomycin, a commonly used antibiotic in the hospitals, destroys the bacterial flora in our small intestine and increase the chance of intestinal infection by another bacteria: Clostridim difficile. Or using penicillin can trigger in 10% of people a hypersensitivity reaction. So in clinical terms many of the the antibiotics side effect are well know of their origin and oxidative stress can explain some of the alien side effects.
ReplyDeleteOne explanation of the result that you report is that people who are treated repeatedly with antibiotics are sicker than people who aren't. Repeated infection would by itself cause bursts of oxidation from the immune system...but in that case, it wouldn't be the antibiotic that was causing damage, but the response to infection. How did researchers control for that possibility?
ReplyDeleteI tried obtaining the actual scientific article through the campus library but that was not possible since they did not have the subscription with the specific journal. At one point, however, the post writer mentioned that the first tests were run on human cultured cells by one scientists and then the study was duplicated and resulted in damage to the cells. Specifically, I learned that antibiotics caused side effects by triggering oxidative stress in the mitochondria.I believe however that this post was mainly about finding a way to do away with antiboitic-induced oxidative stress and find remedies that can lower the stress while it is occurring.I am not much of a biologist but rather chemists and the things that Lori and Mustapha posted were rather important to my learning/remembering of this topic.
ReplyDelete