Here's a rather bizarre thing. Apparently, the vast majority of medical research and new drug testing that makes use of mice and rats actually makes use specifically of MALE mice and rats.
Rodents and humans have a lot of physiology in common, and, as rodents are considered infinitely expendable, they are used in a huge amount of medical research. For reasons that are not immediately apparent, male mice and rats have traditionally been used much more than females, possibly based on the assumption that the hormonal cycles of female animals could make the data less consistent. According to McGill University neuroscientist Jeffrey Mogil, though, data collected from female animal testing is actually no more variable than that collected from male animals (in fact the exact opposite may often be true). Despite increasing awareness of this disparity in medical research , the culture appears very slow to change.
The extent to which this is happening is also not quite clear, particularly as many studies do not even mention the gender of the test subjects. In pain research, though, it is known that 80% of published studies use male mice or rats, even though 70% of people with chronic pain are actually women. According to Mogil, this is probably similar in other fields of medical research, with the rather bizarre exception of immunology, which apparently only uses female animals!
The problem is, men and women respond differently to different drugs and treatments, and so do mice and rats. For example, in male mice, blocking immune cells called glial cells can block pain, but this does not seem to be the case with females. This can then lead to drugs and treatments reaching the market that are ineffective, or even potentially dangerous, for women.
A couple of prominent examples are a stomach drug called cisapride (sold in Canada in the 1990s under the name Prepulsid), which was shown to sometimes cause irregular heartbeat and even sudden death in women only, and sleeping pills containing the drug zolpidem (sold under the brand-name Ambien) which, even given the recommendation that women take half the dose prescribed to men, has been shown to leave women with dangerously high levels the following day. These examples alone are reason to suspect that there may well be gender differences in all kinds of drugs and treatments, both those under development and those already on the market.
Not using both genders in animal testing may also slow down the development of treatments and drugs that are safe and effective for everyone (as is required under Canadian law), because treatments tested on male rodents only may well fail when the much more expensive clinical trials in humans are carried out. This can cause unnecessary delays in new drug treatments, but also substantial wasted money in a field where grant money is hard to come by.
New rules are being apparently being introduced in the US this year requiring both male and female animals to be used in studies in order to qualify for funding (similar rules already exist in Canada, and have done since 2009). However, there is still no requirement, even in Canada, for drug testers to analyze how effective their product is on women and men separately, only an average. So, a drug may actually fail clinical trials (on average) and never be developed, even though it works perfectly well for men. Or, alternatively, a drug may work so well on men that its passes the clinical trials on average, even though it is not effective (and may even be dangerous) for women.
Listen to the interview on CBC's The Current and decide for yourself if this is a big deal or not.
No comments:
Post a Comment