This
article is a truncated version of the original. Essentially, it is saying that
a bug (which goes by the name of Eggerthella Lanta or E. Lanta) can alter the structure of a drug
(digoxin) which is used to treat heart failure and irregular heartbeats. The
bug which resides in our guts causes a chemical change of the drug (digoxin) to
dihydrodigixon and instead of "treating" the patient's heart
problems, it is is quickly excreted out. The researcher (Mr Tambaugh from Havard University) believes that his
discovery has provided an insight into that can lead to improvement of the
delivery of cardiac drugs.
"Bacteria in the human gut, which are
present in the billions, can change the effect of medicine. This has been
demonstrated for at least 40 drugs. But until now, nobody knew exactly how.
"New
research, published in “Science” (http://www.sciencemag.org) by Peter Turnbaugh
at Harvard University, helps solve this riddle, at least for one drug. The team
looked at digoxin, which is used to
treat heart failure and arrhythmia (irregular beats). Digoxin
is only effective within a narrow range of concentrations. This makes getting
the right digoxin dose very tricky—a challenge made more difficult by the gut
bacteria.
The drugs don’t work
"Digoxin
is inactivated by a bacterium (called Eggerthella lenta) found in the gut. The
bug changes the drug’s structure so it cannot interact normally with its
target. This inactive form, called dihydrodigoxin, is also quickly excreted by
the patient. Turnbaugh aimed to find out how the bacterium inactivated the drug
and how to prevent it from doing so.
"To
do this, he and his colleagues used a technique called RNA sequencing.
The effect of diet on drugs
"Turnbaugh
found that the bacteria grew better if fed the amino acid arginine, which is a
component of most proteins. However, too much arginine led to reduced
expression of the two cytochrome genes that inactivated digoxin.
"So
Turnbaugh’s team predicted that eating
more protein would increase the arginine in the gut, which would limit the
inactivation of digoxin by the bacterium (E. lenta). They tested this by
colonizing two sets of mice with the inactivating E. lenta strain and feeding
them different amounts of protein. The mice with higher protein intake had higher
levels of active digoxin in their blood.
"Turnbaugh
believes that the work may show a way to improve the delivery of cardiac drugs.
He feels that the findings demonstrate the importance of understanding how
drugs are inactivated. One day, he suggests, patients may find that their
prescriptions are accompanied by recommended diets or supplements, such as
arginine, that improve the effectiveness of the drugs."
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