Gut flora could explain why cholesterol lowering medicines work sometimes
Bacteria in the gut have been found to influence the way people respond to cholesterol lowering drugs, known as statins. The finding is important for understanding why statins work for some people and not for others. It also highlights how digestion and metabolism influence the effect of drugs.
For the study, researchers looked a data from a sub group of participants enrolled in the Cholesterol and Pharmacogenetics (CAP) study, led by co-author Ronald M. Krauss, M.D., of Children's Hospital Oakland Research Institute.
In a smaller study that examined individual gut flora, Kaddurah-Daouk, Krauss and their team, found 100 people whose ‘bad’ LDL (low density lipoprotein) cholesterol dropped dramatically from taking the drug Zocor, generically known as simvastatin. There were 24 people who had a moderate response and 24 whose cholesterol didn’t respond to the statin.
Next, the researchers analyzed blood work of the study participants before they had been given simvastatin, finding three bile acids produced by gut bacteria that were important for allowing cholesterol medications to work.
Five different bile acids manufactured by gut flora were associated with people who took the cholesterol lowering drugs, but didn’t respond. Bile acids and sterols (fatty substances) break down cholesterol in the body.
Rima Kaddurah-Daouk, Ph.D. who is an associate professor in Duke's Department of Psychiatry and leader of the Pharmacometabolomics Network said, "We found that the benefit of statins could be partly related to the type of bacteria that lives in our guts. The reason we respond differently is not only our genetic makeup, but also our gut microbiome."
The finding suggests gut bacteria are important in the way people respond to drugs. Kaddurah-Daouk said. "It's no doubt that metabolites from bacteria are playing an important role in regulating our systems.”
The researchers say probiotics might boost the effect of certain drugs. It might also be possible to develop a blood test for doctors that would tell them who would benefit from cholesterol lowering drugs and who would not.
The finding explains why cholesterol lowering medications don’t work for everyone. The authors say we are just beginning to understand how microbes in the gut influence health.
Kaddurah-Daouk R, Baillie RA, Zhu H, Zeng Z-B, Wiest MM, et al. (2011) Enteric Microbiome Metabolites Correlate with Response to Simvastatin Treatment. PLoS ONE 6(10): e25482. doi:10.1371/journal.pone.0025482