Recently, I came across
an article on the web that piqued my curiosity. The article was titled “The
effects of metformin and letrozole on endometriosis and comparison of the two
treatment agents in a rat model.” I was interested in the article because the
researchers were using Metformin, an antidiabetic agent in two of the treatment
groups. The fact that Metformin was being tested as a possible treatment for
endometriosis was new and unexpected. I was also interested in the model that
they used, because this is the first that I have personally read about it.
Please allow me to
explain. In order to produce a suitable model in which to study endometriosis,
the researchers had to surgically implant endometriotic tissue into the abdomen
of rats, which produced several small implants or growths in each rat. The rats
were divided into four treatment groups. The treatments were designed to remove
or attenuate the endometrial growths that had been surgically implanted. Group
1 was given water with no medication, Group 2 was given 100 mg/Kg/day of Metformin,
Group 3 was given 200 mg/Kg/day of Metformin, and Group 4 was given 0.1 mg/Kg/day
of Letrozole, an aromatase inhibitor. Aromatase Inhibitors are designed to
block the production of estrogen in vivo. Basically, endometriosis
feeds on estrogen.
The rats were given
their respective medical treatments for four weeks, and at the end of four
weeks the rats were surgically re-examined. The implants were then scored based
on their severity.
All three of the groups
that were receiving medication had a statistically significant reduction in the
extent of their surgically-induced endometriosis. Group 2 had the best
treatment outcome when both the surface area of the implants and the amount of
adhesion formation was taken into account. Adhesions are a type of scar tissue
that can form in the abdominal cavity due to endometriosis, surgery or
infection/inflammation.
So how does Metformin,
an antidiabetic agent reduce the size/severity of endometriotic implants and adhesions?
The authors of the article believe that Metformin can reduce inflammation and
inhibit some estrogen production. Metformin seems like a medical multitasker,
indeed.
Why were the doses of medication so high?
The normal human dose of Letrozole is 2.5 mg per day, and the maximum dose of
Metformin is 2,550 mg per day divided into three doses of 850 mg. In a
relatively small person of 50 Kg (110 lbs.), a 100 mg/Kg/day dosing of Metformin
would be 5,000 mg daily, and the dosage of 0.1 mg/Kg/day of Letrozole in a 50
Kg person would be 5.0 mg daily. This is twice the amount of medication
normally given, and the doses would be even higher in a heavier person.
In conclusion, I am curious about
the details of this article, but I would be remiss if I did not also mention
that this article does contribute in an important way to the body of research on
endometriosis. I would be excited to read more research about Metformin and endometriosis in
the future. From the details provided in the article, Metformin seems like it may have potential as a treatment for endometriosis. The free full text of this article is available online from the
publisher.
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