Teenagers with acne may need to think twice before starting a common antibiotic treatment meant to resolve skin issues. A new study has found that antibiotic treatment may alter the skeletal system with long-lasting effects.

The study, published in the Journal of Clinical Investigation (JCI) Insight, showed that long-term topical use of a systemic antibiotic, minocycline, may have unintended effects during adolescent bone development.

Minocycline treatment can last for up to two years. This antibiotic alters the gut microbiome—the population of microorganisms that live in the gut.

Researchers from the Medical University of South Carolina (MUSC) found a strong correlation between the composition of the gut microbiome and healthy skeletal maturation.

For the study, the research team gave an appropriate dose of minocycline to mice during the pubertal/postpubertal growth stage, which is the equivalent age of adolescence in humans.

It was found in the study that though minocycline therapy did not cause any cytotoxic effects or induce a pro-inflammatory response, it did change the composition of the gut microbiome which led to decreased bone mass accrual and inefficient skeletal maturation.

"There are sustained changes to the gut microbiome following long-term systemic minocycline therapy that leads to reduced bone maturation," first author, Matthew Carson, Novince lab, said, reported SciTechDaily.

"From a clinical perspective, not only is minocycline treatment causing changes to the maturing skeleton, the microbiome and the skeleton aren't able to recover fully after antibiotic therapy," Chad Novince, principal investigator and associate professor in the Department of Oral Health Sciences in the College of Dental Medicine added.

Minocycline belongs to the tetracycline class of antibiotics. This group also includes antibiotics such as tetracycline, doxycycline, and sarecycline. These antibiotics work by obstructing the growth and spread of bacteria. In the case of acne, they kill the bacteria that infect pores and reduce certain acne-causing natural oily substances.

"What's really interesting is if you cause changes to the microbiome during this adolescent phase when your microbiota is still progressing toward a stable adult state, you're going to have profound effects on the maturing skeleton," Carson said, as per the outlet.

Interestingly, the team found that the changes in the gut microbiome due to minocycline also affected the communication between the liver and the small intestine, which takes place through molecules called bile acids.

"Bile acids had not previously been considered as important communication molecules between the gut and the skeleton," Novince said, according to the outlet. "By changing the gut microbiome, the makeup of the bile acids is altered, which influences host physiology, including skeletal maturation."

The altered gut microbiome created a different pool of bile acids. These different types of bile acids could not activate bone-forming cells called osteoblasts, which, in turn, decreased bone formation and mineralization by more than 30%.

"This was truly collaborative science, which is where I think we're at today," Novince said. "To drive high-impact science, you need to bring in experts from different professions and disciplines. We were fortunate to have a really strong team. It was fun – the whole thing was exciting!"

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